Issue published October 1, 2014 Previous issue | Next issue
- Volume 124, Issue 10
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On the cover: Celebrating 90 years of publishing scientific discoveries in medicine
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Reviews
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Abstract
The past decade has been one of rapid innovation in genome-editing technology. The opportunity now exists for investigators to manipulate virtually any gene in a diverse range of cell types and organisms with targeted nucleases designed with sequence-specific DNA-binding domains. The rapid development of the field has allowed for highly efficient, precise, and now cost-effective means by which to generate human and animal models of disease using these technologies. This review will outline the recent development of genome-editing technology, culminating with the use of CRISPR-Cas9 to generate novel mammalian models of disease. While the road to using this same technology for treatment of human disease is long, the pace of innovation over the past five years and early successes in model systems build anticipation for this prospect.
Authors
Rajat M. Gupta, Kiran Musunuru
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The collection of bacteria, viruses, and fungi that live in and on the human body, collectively known as the microbiome, has recently emerged as an important factor in human physiology and disease. The gut in particular is a biological niche that is home to a diverse array of microbes that influence nearly all aspects of human biology through their interactions with their host; new technologies are beginning to reveal important aspects of host-microbe interactions. Articles in this Review series address how perturbations of the microbiota, such as through antibiotic use, influence its overall structure and function; how our microbiome influences the impact of infectious agents, such as
C. difficile ; how our microbiome mediates metabolism of xenobiotics; how the microbiota contribute to immunity as well as to metabolic and inflammatory diseases; and the role of commensal microbes in oncogenesis.Authors
Martin J. Blaser
×Abstract
The human body comprises fewer host cells than bacterial cells, most of which are obligate anaerobes residing in the gut. The symbiont
Bacteroides fragilis constitutes a relatively small proportion (up to 1%–2%) of cultured fecal bacteria, but colonizes most humans. There are 2 classes ofB .fragilis distinguished by their ability to secrete a zinc-dependent metalloprotease toxin,B .fragilis toxin (BFT). Strains that do not secrete BFT are nontoxigenicB .fragilis (NTBF), and those that do are called enterotoxigenicB .fragilis (ETBF). ETBF can induce clinical pathology, including inflammatory diarrhea, although asymptomatic colonization may be common. Intestinal inflammation is mediated by BFT, as yet the only known virulence factor of ETBF. Recent experimental evidence demonstrating that ETBF-driven colitis promotes colon tumorigenesis has generated interest in the potential contribution of ETBF to human colon carcinogenesis. Critical questions about the epidemiology of chronic, subclinical human colonization with ETBF and its impact on the biology of the colon need to be addressed.Authors
Cynthia L. Sears, Abby L. Geis, Franck Housseau
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Our associated microbial communities play a critical role in human health and predisposition to disease, but the degree to which they also shape therapeutic interventions is not well understood. Here, we integrate results from classic and current studies of the direct and indirect impacts of the gut microbiome on the metabolism of therapeutic drugs and diet-derived bioactive compounds. We pay particular attention to microbial influences on host responses to xenobiotics, adding to the growing consensus that treatment outcomes reflect our intimate partnership with the microbial world, and providing an initial framework from which to consider a more comprehensive view of pharmacology and nutrition.
Authors
Rachel N. Carmody, Peter J. Turnbaugh
×Abstract
Clostridium difficile infection (CDI) is the leading health care–associated illness. Both human and animal models have demonstrated the importance of the gut microbiota’s capability of providing colonization resistance againstC. difficile . Risk factors for disease development include antibiotic use, which disrupts the gut microbiota, leading to the loss of colonization resistance and subsequent CDI. Identification of the specific microbes capable of restoring this function remains elusive. Future studies directed at how microbial communities influence the metabolic environment may help elucidate the role of the microbiota in disease development. These findings will improve current biotherapeutics for patients with CDI, particularly those with recurrent disease.Authors
Anna M. Seekatz, Vincent B. Young
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Inflammatory bowel diseases (IBD) are chronic, progressive diseases characterized by aberrant immune responses to environmental and gut microbial triggers in genetically susceptible hosts. Clinical, genetic, and experimental data support the role of gut microbes in causing and sustaining these diseases. Our understanding of IBD has changed dramatically as the result of advances in cultivation-independent approaches and computational platforms for the analysis of large data sets. However, investigations relevant to clinical observations and the natural history of the diseases will be essential for the development of microbial, genetic, and biological metrics that may be used to individualize assessment of risk and improve clinical outcomes in IBD.
Authors
Sushila R. Dalal, Eugene B. Chang
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The past decade has witnessed an explosion in studies — both clinical and basic science — examining the relationship between the microbiota and human health, and it is now clear that the effects of commensal organisms are much broader than previously believed. Among the microbiota’s major contributions to host physiology is regulation of the development and maintenance of the immune system. There are now a handful of examples of intestinal commensal bacteria with defined immunomodulatory properties, but our mechanistic understanding of how microbes influence the immune system is still in its infancy. Nevertheless, several themes have emerged that provide a framework for appreciating microbe-induced immunoregulation. In this Review, we discuss the current state of knowledge regarding the role of the intestinal microbiota in immunologic development, highlighting mechanistic principles that can guide future work.
Authors
Neeraj K. Surana, Dennis L. Kasper
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Our group recently discovered that certain dietary nutrients possessing a trimethylamine (TMA) moiety, namely choline/phosphatidylcholine and L-carnitine, participate in the development of atherosclerotic heart disease. A meta-organismal pathway was elucidated involving gut microbiota–dependent formation of TMA and host hepatic flavin monooxygenase 3–dependent (FMO3-dependent) formation of TMA–N-oxide (TMAO), a metabolite shown to be both mechanistically linked to atherosclerosis and whose levels are strongly linked to cardiovascular disease (CVD) risks. Collectively, these studies reveal that nutrient precursors, gut microbiota, and host participants along the meta-organismal pathway elucidated may serve as new targets for the prevention and treatment of CVD.
Authors
W.H. Wilson Tang, Stanley L. Hazen
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Antibiotics have been a cornerstone of innovation in the fields of public health, agriculture, and medicine. However, recent studies have shed new light on the collateral damage they impart on the indigenous host-associated communities. These drugs have been found to alter the taxonomic, genomic, and functional capacity of the human gut microbiota, with effects that are rapid and sometimes persistent. Broad-spectrum antibiotics reduce bacterial diversity while expanding and collapsing membership of specific indigenous taxa. Furthermore, antibiotic treatment selects for resistant bacteria, increases opportunities for horizontal gene transfer, and enables intrusion of pathogenic organisms through depletion of occupied natural niches, with profound implications for the emergence of resistance. Because these pervasive alterations can be viewed as an uncoupling of mutualistic host-microbe relationships, it is valuable to reconsider antimicrobial therapies in the context of an ecological framework. Understanding the biology of competitive exclusion, interspecies protection, and gene flow of adaptive functions in the gut environment may inform the design of new strategies that treat infections while preserving the ecology of our beneficial constituents.
Authors
Sheetal R. Modi, James J. Collins, David A. Relman
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Commentaries
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Abstract
Male germline or spermatogonial stem cells (SSCs) are conserved across many species and essential for uninterrupted production of sperm over long periods of reproductive life span. A better understanding of SSC biology provides limitless opportunities in male reproductive health, fertility preservation, and regenerative medicine. Although several potential markers define SSCs, not many definitive markers exist that are specific for a rare subset of SSCs that self-renew and have the ability to give rise to other progenitors, eventually contributing to all stages of spermatogenesis. In the September 2014 issue of the
JCI , Aloisio and colleagues report that PAX7 is a new marker expressed uniquely in a rare subset of SSCs in mouse testes. PAX7+ cells fulfill all the criteria required for bona fide SSCs. Surprisingly, male germline-specific deletion ofPax7 indicates that it is dispensable for spermatogenesis.Authors
T. Rajendra Kumar
×Abstract
The peptide hormone glucagon-like peptide-1 (GLP-1) enhances glucose-induced insulin secretion and inhibits both gastric emptying and glucagon secretion. GLP-1 receptor (GLP-1R) agonists control glycemia via glucose-dependent mechanisms of action and promote weight loss in obese and diabetic individuals. Nevertheless, the mechanisms and cellular targets transducing the weight loss effects remain unclear. Two recent studies in the
JCI provide insight into the neurons responsible for this effect. Sisley et al. reveal that GLP-1R agonist–induced weight loss requires GLP-1Rs in the CNS, while Secher et al. reveal that a small peptide GLP-1R agonist penetrates the brain and activates a subset of GLP-1R–expressing neurons in the arcuate nucleus to produce weight loss. Together, these two studies elucidate pathways that inform strategies coupling GLP-1R signaling to control of body weight in patients with diabetes or obesity.Authors
Laurie L. Baggio, Daniel J. Drucker
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Paroxysmal nocturnal hemoglobinuria (PNH) is a disorder of hematopoietic stem cells that has largely been considered a monogenic disorder due to acquisition of mutations in the gene encoding PIGA, which is required for glycosylphosphatidylinositol (GPI) anchor biosynthesis. In this issue of the
JCI , Shen et al. discovered that PNH is in fact a complex genetic disorder orchestrated by many genetic alterations in addition toPIGA mutations. Some of these mutations predate the acquisition ofPIGA mutations, while others occur later. Surprisingly, this work indicates that PNH has a clonal evolution and architecture strikingly similar to that of other myeloid neoplasms, highlighting a potentially broader mechanism of disease pathogenesis in this disorder.Authors
Stanley Chun-Wei Lee, Omar Abdel-Wahab
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Details of the pathophysiologic mechanisms that underlie complex disorders, such as the thrombo-occlusive events associated with myocardial infarction, stroke, and venous thromboembolism, are challenging to address. Recent advances have been made through the application of genome-wide association studies (GWAS) to identify genetic loci associated with plasma levels of procoagulant proteins and risk of thrombotic disease. GWAS have consistently identified the gene encoding syntaxin-binding protein 5 (STXBP5) in this context. STXBP5 is expressed in both endothelium and platelets, and SNPs within the
STXBP5 locus have been associated with plasma levels of vWF and increased venous thrombosis risk. In this issue of theJCI , two complementary reports from the laboratories of Charles Lowenstein and Sidney Whiteheart describe studies that highlight the complexity of the function of STXBP5 in control of storage granule development and exocytosis in platelets and endothelium. Together, these studies demonstrate that STXBP5 differentially regulates exocytosis in these two cell types. While STXBP5 facilitates granule release from platelets, it inhibits secretion from the Weibel-Palade bodies (WPBs) of endothelial cells.Authors
David Lillicrap
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T cells are required for significant blood pressure elevation in mouse models of hypertension. Recent evidence suggests that the treatments that raise blood pressure in these animal models also cause oxidation within DCs, resulting in formation of isoketal adducts of self-proteins, which activate antigen-presenting functions of these cells and serve as a source of modified self-antigens. T cells specific for these modified self-antigens then produce cytokines that promote blood pressure elevation, consistent with the idea that hypertension is an autoimmune response to altered self. Here, I will review the new evidence for this idea put forth by Kirabo and colleagues in this issue of the
JCI , identify a number of as yet unanswered questions, and discuss some of the therapeutic implications.Authors
Jordan S. Pober
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Neutrophils exert potent antimicrobial activities in their role as first-line cellular defenders against infection. The synergistic and collective actions of oxidants and granule proteins, including serine proteases, support the microbial killing in phagosomes, where most neutrophil-mediated antimicrobial action occurs. In addition to phagocytosis, specific stimuli prompt neutrophils to extrude a matrix of DNA, histones, and granule proteins to produce neutrophil extracellular traps (NETs), which can trap microbes. Mice lacking the serine proteases necessary for NET production are more susceptible to infection, an observation suggesting that functional NETs are required for host protection. In this issue of the
JCI , Sørensen and colleagues characterize neutrophils from a patient with Papillon-Lefèvre syndrome. The patient has an inactivating mutation in the gene encoding dipeptidyl peptidase I, resulting in neutrophils lacking elastase, a serine protease required for NET production. Despite the inability to form NETS, neutrophils from this patient killed pathogens in vitro, and the patient did not exhibit evidence of an increased propensity toward bacterial infections. Together, these results suggest that proteases in human neutrophils are dispensable for protection against bacterial infection and that the ability to generate NETs in vitro does not compromise host defense.Authors
William M. Nauseef
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Research Articles
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Abstract
We previously positionally cloned
Sorcs1 as a diabetes quantitative trait locus.Sorcs1 belongs to the Vacuolar protein sorting-10 (Vps10) gene family. In yeast, Vps10 transports enzymes from thetrans -Golgi network (TGN) to the vacuole. Whole-bodySorcs1 KO mice, when made obese with theleptinob mutation (ob/ob ), developed diabetes. β Cells from these mice had a severe deficiency of secretory granules (SGs) and insulin. Interestingly, a single secretagogue challenge failed to consistently elicit an insulin secretory dysfunction. However, multiple challenges of theSorcs1 KOob/ob islets consistently revealed an insulin secretion defect. The luminal domain of SORCS1 (Lum-Sorcs1 ), when expressed in a β cell line, acted as a dominant-negative, leading to SG and insulin deficiency. Using syncollin-dsRed5TIMER adenovirus, we found that the loss ofSorcs1 function greatly impairs the rapid replenishment of SGs following secretagogue challenge. Chronic exposure of islets from leanSorcs1 KO mice to high glucose and palmitate depleted insulin content and evoked an insulin secretion defect. Thus, in metabolically stressed mice,Sorcs1 is important for SG replenishment, and under chronic challenge by insulin secretagogues, loss ofSorcs1 leads to diabetes. Overexpression of full-length SORCS1 led to a 2-fold increase in SG content, suggesting that SORCS1 is sufficient to promote SG biogenesis.Authors
Melkam A. Kebede, Angie T. Oler, Trillian Gregg, Allison J. Balloon, Adam Johnson, Kelly Mitok, Mary Rabaglia, Kathryn Schueler, Donald Stapleton, Candice Thorstenson, Lindsay Wrighton, Brendan J. Floyd, Oliver Richards, Summer Raines, Kevin Eliceiri, Nabil G. Seidah, Christopher Rhodes, Mark P. Keller, Joshua L. Coon, Anjon Audhya, Alan D. Attie
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Muscle satellite cells promote regeneration and could potentially improve gene delivery for treating muscular dystrophies. Human satellite cells are scarce; therefore, clinical investigation has been limited. We obtained muscle fiber fragments from skeletal muscle biopsy specimens from adult donors aged 20 to 80 years. Fiber fragments were manually dissected, cultured, and evaluated for expression of myogenesis regulator PAX7. PAX7+ satellite cells were activated and proliferated efficiently in culture. Independent of donor age, as few as 2 to 4 PAX7+ satellite cells gave rise to several thousand myoblasts. Transplantation of human muscle fiber fragments into irradiated muscle of immunodeficient mice resulted in robust engraftment, muscle regeneration, and proper homing of human PAX7+ satellite cells to the stem cell niche. Further, we determined that subjecting the human muscle fiber fragments to hypothermic treatment successfully enriches the cultures for PAX7+ cells and improves the efficacy of the transplantation and muscle regeneration. Finally, we successfully altered gene expression in cultured human PAX7+ satellite cells with Sleeping Beauty transposon–mediated nonviral gene transfer, highlighting the potential of this system for use in gene therapy. Together, these results demonstrate the ability to culture and manipulate a rare population of human tissue-specific stem cells and suggest that these PAX7+ satellite cells have potential to restore gene function in muscular dystrophies.
Authors
Andreas Marg, Helena Escobar, Sina Gloy, Markus Kufeld, Joseph Zacher, Andreas Spuler, Carmen Birchmeier, Zsuzsanna Izsvák, Simone Spuler
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Chronic GVHD (cGVHD) is the major cause of late, nonrelapse death following stem cell transplantation and characteristically develops in organs such as skin and lung. Here, we used multiple murine models of cGVHD to investigate the contribution of macrophage populations in the development of cGVHD. Using an established IL-17–dependent sclerodermatous cGVHD model, we confirmed that macrophages infiltrating the skin are derived from donor bone marrow (F4/80+CSF-1R+CD206+iNOS–). Cutaneous cGVHD developed in a CSF-1/CSF-1R–dependent manner, as treatment of recipients after transplantation with CSF-1 exacerbated macrophage infiltration and cutaneous pathology. Additionally, recipients of grafts from
Csf1r–/– mice had substantially less macrophage infiltration and cutaneous pathology as compared with those receiving wild-type grafts. Neither CCL2/CCR2 nor GM-CSF/GM-CSFR signaling pathways were required for macrophage infiltration or development of cGVHD. In a different cGVHD model, in which bronchiolitis obliterans is a prominent manifestation, F4/80+ macrophage infiltration was similarly noted in the lungs of recipients after transplantation, and lung cGVHD was also IL-17 and CSF-1/CSF-1R dependent. Importantly, depletion of macrophages using an anti–CSF-1R mAb markedly reduced cutaneous and pulmonary cGVHD. Taken together, these data indicate that donor macrophages mediate the development of cGVHD and suggest that targeting CSF-1 signaling after transplantation may prevent and treat cGVHD.Authors
Kylie A. Alexander, Ryan Flynn, Katie E. Lineburg, Rachel D. Kuns, Bianca E. Teal, Stuart D. Olver, Mary Lor, Neil C. Raffelt, Motoko Koyama, Lucie Leveque, Laetitia Le Texier, Michelle Melino, Kate A. Markey, Antiopi Varelias, Christian Engwerda, Jonathan S. Serody, Baptiste Janela, Florent Ginhoux, Andrew D. Clouston, Bruce R. Blazar, Geoffrey R. Hill, Kelli P.A. MacDonald
×Abstract
Plasma fibronectin (pFn) has long been suspected to be involved in hemostasis; however, direct evidence has been lacking. Here, we demonstrated that pFn is vital to control bleeding in fibrinogen-deficient mice and in WT mice given anticoagulants. At the site of vessel injury, pFn was rapidly deposited and initiated hemostasis, even before platelet accumulation, which is considered the first wave of hemostasis. This pFn deposition was independent of fibrinogen, von Willebrand factor, β3 integrin, and platelets. Confocal and scanning electron microscopy revealed pFn integration into fibrin, which increased fibrin fiber diameter and enhanced the mechanical strength of clots, as determined by thromboelastography. Interestingly, pFn promoted platelet aggregation when linked with fibrin but inhibited this process when fibrin was absent. Therefore, pFn may gradually switch from supporting hemostasis to inhibiting thrombosis and vessel occlusion following the fibrin gradient that decreases farther from the injured endothelium. Our data indicate that pFn is a supportive factor in hemostasis, which is vital under both genetic and therapeutic conditions of coagulation deficiency. By interacting with fibrin and platelet β3 integrin, pFn plays a self-limiting regulatory role in thrombosis, suggesting pFn transfusion may be a potential therapy for bleeding disorders, particularly in association with anticoagulant therapy.
Authors
Yiming Wang, Adili Reheman, Christopher M. Spring, Jalil Kalantari, Alexandra H. Marshall, Alisa S. Wolberg, Peter L. Gross, Jeffrey I. Weitz, Margaret L. Rand, Deane F. Mosher, John Freedman, Heyu Ni
×Abstract
The transport and intracellular trafficking of heme biosynthesis intermediates are crucial for hemoglobin production, which is a critical process in developing red cells. Here, we profiled gene expression in terminally differentiating murine fetal liver-derived erythroid cells to identify regulators of heme metabolism. We determined that TMEM14C, an inner mitochondrial membrane protein that is enriched in vertebrate hematopoietic tissues, is essential for erythropoiesis and heme synthesis in vivo and in cultured erythroid cells. In mice, TMEM14C deficiency resulted in porphyrin accumulation in the fetal liver, erythroid maturation arrest, and embryonic lethality due to profound anemia. Protoporphyrin IX synthesis in TMEM14C-deficient erythroid cells was blocked, leading to an accumulation of porphyrin precursors. The heme synthesis defect in TMEM14C-deficient cells was ameliorated with a protoporphyrin IX analog, indicating that TMEM14C primarily functions in the terminal steps of the heme synthesis pathway. Together, our data demonstrate that TMEM14C facilitates the import of protoporphyrinogen IX into the mitochondrial matrix for heme synthesis and subsequent hemoglobin production. Furthermore, the identification of TMEM14C as a protoporphyrinogen IX importer provides a genetic tool for further exploring erythropoiesis and congenital anemias.
Authors
Yvette Y. Yien, Raymond F. Robledo, Iman J. Schultz, Naoko Takahashi-Makise, Babette Gwynn, Daniel E. Bauer, Abhishek Dass, Gloria Yi, Liangtao Li, Gordon J. Hildick-Smith, Jeffrey D. Cooney, Eric L. Pierce, Kyla Mohler, Tamara A. Dailey, Non Miyata, Paul D. Kingsley, Caterina Garone, Shilpa M. Hattangadi, Hui Huang, Wen Chen, Ellen M. Keenan, Dhvanit I. Shah, Thorsten M. Schlaeger, Salvatore DiMauro, Stuart H. Orkin, Alan B. Cantor, James Palis, Carla M. Koehler, Harvey F. Lodish, Jerry Kaplan, Diane M. Ward, Harry A. Dailey, John D. Phillips, Luanne L. Peters, Barry H. Paw
×Abstract
Metastasis causes most cancer deaths, but is incompletely understood. MicroRNAs can regulate metastasis, but it is not known whether a single miRNA can regulate metastasis in primary cancer models in vivo. We compared the expression of miRNAs in metastatic and nonmetastatic primary mouse sarcomas and found that microRNA-182 (miR-182) was markedly overexpressed in some tumors that metastasized to the lungs. By utilizing genetically engineered mice with either deletion of or overexpression of miR-182 in primary sarcomas, we discovered that deletion of miR-182 substantially decreased, while overexpression of miR-182 considerably increased, the rate of lung metastasis after amputation of the tumor-bearing limb. Additionally, deletion of miR-182 decreased circulating tumor cells (CTCs), while overexpression of miR-182 increased CTCs, suggesting that miR-182 regulates intravasation of cancer cells into the circulation. We identified 4 miR-182 targets that inhibit either the migration of tumor cells or the degradation of the extracellular matrix. Notably, restoration of any of these targets in isolation did not alter the metastatic potential of sarcoma cells injected orthotopically, but the simultaneous restoration of all 4 targets together substantially decreased the number of metastases. These results demonstrate that a single miRNA can regulate metastasis of primary tumors in vivo by coordinated regulation of multiple genes.
Authors
Mohit Sachdeva, Jeffrey K. Mito, Chang-Lung Lee, Minsi Zhang, Zhizhong Li, Rebecca D. Dodd, David Cason, Lixia Luo, Yan Ma, David Van Mater, Rebecca Gladdy, Dina C. Lev, Diana M. Cardona, David G. Kirsch
×Abstract
Glaucoma is a leading cause of blindness, afflicting more than 60 million people worldwide. Increased intraocular pressure (IOP) due to impaired aqueous humor drainage is a major risk factor for the development of glaucoma. Here, we demonstrated that genetic disruption of the angiopoietin/TIE2 (ANGPT/TIE2) signaling pathway results in high IOP, buphthalmos, and classic features of glaucoma, including retinal ganglion degeneration and vision loss. Eyes from mice with induced deletion of
Angpt1 andAngpt2 (A1A2FloxWB mice) lacked drainage pathways in the corneal limbus, including Schlemm’s canal and lymphatic capillaries, which share expression of the PROX1, VEGFR3, and FOXC family of transcription factors. VEGFR3 and FOXCs have been linked to lymphatic disorders in patients, and FOXC1 has been linked to glaucoma. In contrast to blood endothelium, in which ANGPT2 is an antagonist of ANGPT1, we have shown that both ligands cooperate to regulate TIE2 in the lymphatic network of the eye. While A1A2FloxWB mice developed high IOP and glaucoma, expression of ANGPT1 or ANGPT2 alone was sufficient for ocular drainage. Furthermore, we demonstrated that loss of FOXC2 from lymphatics results in TIE2 downregulation, suggesting a mechanism for ocular defects in patients with FOXC mutations. These data reveal a pathogenetic and molecular basis for glaucoma and demonstrate the importance of angiopoietin ligand cooperation in the lymphatic endothelium.Authors
Benjamin R. Thomson, Stefan Heinen, Marie Jeansson, Asish K. Ghosh, Anees Fatima, Hoon-Ki Sung, Tuncer Onay, Hui Chen, Shinji Yamaguchi, Aris N. Economides, Ann Flenniken, Nicholas W. Gale, Young-Kwon Hong, Amani Fawzi, Xiaorong Liu, Tsutomu Kume, Susan E. Quaggin
×Abstract
Millions of patients worldwide are affected by craniofacial deformations caused by congenital defects or trauma. Current surgical interventions have limited therapeutic outcomes; therefore, methods that would allow cartilage restoration are of great interest. A number of studies on embryonic limb development have shown that chondrogenesis is initiated by cellular condensation, during which mesenchymal progenitors aggregate and form 3D structures. Here, we demonstrated efficient regeneration of avascular elastic cartilage from in vitro–grown mesenchymal condensation, which recapitulated the early stages of chondrogenesis, including transient vascularization. After transplantation of vascularized condensed progenitors into immunodeficient mice, we used an intravital imaging approach to follow cartilage maturation. We determined that endothelial cells are present inside rudimentary cartilage (mesenchymal condensation) prior to cartilage maturation. Recreation of endothelial interactions in culture enabled a recently identified population of adult elastic cartilage progenitors to generate mesenchymal condensation in a self-driven manner, without requiring the support of exogenous inductive factors or scaffold materials. Moreover, the culture-grown 3D condensed adult–derived progenitors were amenable to storage via simple freezing methods and efficiently reconstructed 3D elastic cartilage upon transplantation. Together, our results indicate that transplantation of endothelialized and condensed progenitors represents a promising approach to realizing a regenerative medicine treatment for craniofacial deformations.
Authors
Takanori Takebe, Shinji Kobayashi, Hiromu Suzuki, Mitsuru Mizuno, Yu-Min Chang, Emi Yoshizawa, Masaki Kimura, Ayaka Hori, Jun Asano, Jiro Maegawa, Hideki Taniguchi
×Abstract
While tumor blood vessels share many characteristics with normal vasculature, they also exhibit morphological and functional aberrancies. For example, the neural adhesion molecule L1, which mediates neurite outgrowth, fasciculation, and pathfinding, is expressed on tumor vasculature. Here, using an orthotopic mouse model of pancreatic carcinoma, we evaluated L1 functionality in cancer vessels. Tumor-bearing mice specifically lacking L1 in endothelial cells or treated with anti-L1 antibodies exhibited decreased angiogenesis and improved vascular stabilization, leading to reduced tumor growth and metastasis. In line with these dramatic effects of L1 on tumor vasculature, the ectopic expression of L1 in cultured endothelial cells (ECs) promoted phenotypical and functional alterations, including proliferation, migration, tubulogenesis, enhanced vascular permeability, and endothelial-to-mesenchymal transition. L1 induced global changes in the EC transcriptome, altering several regulatory networks that underlie endothelial pathophysiology, including JAK/STAT-mediated pathways. In particular, L1 induced IL-6–mediated STAT3 phosphorylation, and inhibition of the IL-6/JAK/STAT signaling axis prevented L1-induced EC proliferation and migration. Evaluation of patient samples revealed that, compared with that in noncancerous tissue, L1 expression is specifically enhanced in blood vessels of human pancreatic carcinomas and in vessels of other tumor types. Together, these data indicate that endothelial L1 orchestrates multiple cancer vessel functions and represents a potential target for tumor vascular-specific therapies.
Authors
Elena Magrini, Alessandra Villa, Francesca Angiolini, Andrea Doni, Giovanni Mazzarol, Noemi Rudini, Luigi Maddaluno, Mina Komuta, Baki Topal, Hans Prenen, Melitta Schachner, Stefano Confalonieri, Elisabetta Dejana, Fabrizio Bianchi, Massimiliano Mazzone, Ugo Cavallaro
×Abstract
Binge eating afflicts approximately 5% of US adults, though effective treatments are limited. Here, we showed that estrogen replacement substantially suppresses binge-like eating behavior in ovariectomized female mice. Estrogen-dependent inhibition of binge-like eating was blocked in female mice specifically lacking estrogen receptor-α (ERα) in serotonin (5-HT) neurons in the dorsal raphe nuclei (DRN). Administration of a recently developed glucagon-like peptide-1–estrogen (GLP-1–estrogen) conjugate designed to deliver estrogen to GLP1 receptor–enhanced regions effectively targeted bioactive estrogens to the DRN and substantially suppressed binge-like eating in ovariectomized female mice. Administration of GLP-1 alone reduced binge-like eating, but not to the same extent as the GLP-1–estrogen conjugate. Administration of ERα-selective agonist propylpyrazole triol (PPT) to murine DRN 5-HT neurons activated these neurons in an ERα-dependent manner. PPT also inhibited a small conductance Ca2+-activated K+ (SK) current; blockade of the SK current prevented PPT-induced activation of DRN 5-HT neurons. Furthermore, local inhibition of the SK current in the DRN markedly suppressed binge-like eating in female mice. Together, our data indicate that estrogens act upon ERα to inhibit the SK current in DRN 5-HT neurons, thereby activating these neurons to suppress binge-like eating behavior and suggest ERα and/or SK current in DRN 5-HT neurons as potential targets for anti-binge therapies.
Authors
Xuehong Cao, Pingwen Xu, Mario G. Oyola, Yan Xia, Xiaofeng Yan, Kenji Saito, Fang Zou, Chunmei Wang, Yongjie Yang, Antentor Hinton Jr., Chunling Yan, Hongfang Ding, Liangru Zhu, Likai Yu, Bin Yang, Yuxin Feng, Deborah J. Clegg, Sohaib Khan, Richard DiMarchi, Shaila K. Mani, Qingchun Tong, Yong Xu
×Abstract
The NF-κB signaling pathway is implicated in various inflammatory diseases, including rheumatoid arthritis (RA); therefore, inhibition of this pathway has the potential to ameliorate an array of inflammatory diseases. Given that NF-κB signaling is critical for many immune cell functions, systemic blockade of this pathway may lead to detrimental side effects. siRNAs coupled with a safe and effective delivery nanoplatform may afford the specificity lacking in systemic administration of small-molecule inhibitors. Here we demonstrated that a melittin-derived cationic amphipathic peptide combined with siRNA targeting the p65 subunit of NF-κB (p5RHH-p65) noncovalently self-assemble into stable nanocomplexes that home to the inflamed joints in a murine model of RA. Specifically, administration of p5RHH-p65 siRNA nanocomplexes abrogated inflammatory cytokine expression and cellular influx into the joints, protected against bone erosions, and preserved cartilage integrity. The p5RHH-p65 siRNA nanocomplexes potently suppressed early inflammatory arthritis without affecting p65 expression in off-target organs or eliciting a humoral response after serial injections. These data suggest that this self-assembling, largely nontoxic platform may have broad utility for the specific delivery of siRNA to target and limit inflammatory processes for the treatment of a variety of diseases.
Authors
Hui-fang Zhou, Huimin Yan, Hua Pan, Kirk K. Hou, Antonina Akk, Luke E. Springer, Ying Hu, J. Stacy Allen, Samuel A. Wickline, Christine T.N. Pham
×Abstract
T follicular helper (Tfh) cells contribute to the establishment of humoral immunity by controlling the delivery of helper signals to activated B cells; however, Tfh development must be restrained, as aberrant accumulation of these cells is associated with positive selection of self-reactive germinal center B cells and autoimmunity in both humans and mice. Here, we show that TGF-β signaling in T cells prevented Tfh cell accumulation, self-reactive B cell activation, and autoantibody production. Using mice with either T cell–specific loss or constitutive activation of TGF-β signaling, we demonstrated that TGF-β signaling is required for the thymic maturation of CD44+CD122+Ly49+CD8+ regulatory T cells (Tregs), which induce Tfh apoptosis and thus regulate this cell population. Moreover, peripheral Tfh cells escaping TGF-β control were resistant to apoptosis, exhibited high levels of the antiapoptotic protein BCL2, and remained refractory to regulation by CD8+ Tregs. The unrestrained accumulation of Tfh cells in the absence of TGF-β was dependent on T cell receptor engagement and required B cells. Together, these data indicate that TGF-β signaling restrains Tfh cell accumulation and B cell–associated autoimmunity and thereby controls self-tolerance.
Authors
Mark J. McCarron, Julien C. Marie
×Abstract
BACKGROUND. Anemia, or low blood hemoglobin (Hgb) levels, afflicts 2 billion people worldwide. Currently, Hgb levels are typically measured from blood samples using hematology analyzers, which are housed in hospitals, clinics, or commercial laboratories and require skilled technicians to operate. A reliable, inexpensive point-of-care (POC) Hgb test would enable cost-effective anemia screening and chronically anemic patients to self-monitor their disease. We present a rapid, stand-alone, and disposable POC anemia test that, via a single drop of blood, outputs color-based visual results that correlate with Hgb levels.METHODS. We tested blood from 238 pediatric and adult patients with anemia of varying degrees and etiologies and compared hematology analyzer Hgb levels with POC Hgb levels, which were estimated via visual interpretation using a color scale and an optional smartphone app for automated analysis.RESULTS. POC Hgb levels correlated with hematology analyzer Hgb levels (r = 0.864 andr = 0.856 for visual interpretation and smartphone app, respectively), and both POC test methods yielded comparable sensitivity and specificity for detecting any anemia (n = 178) (<11 g/dl) (sensitivity: 90.2% and 91.1%, specificity: 83.7% and 79.2%, respectively) and severe anemia (n = 10) (<7 g/dl) (sensitivity: 90.0% and 100%, specificity: 94.6% and 93.9%, respectively).CONCLUSIONS. These results demonstrate the feasibility of this POC color-based diagnostic test for self-screening/self-monitoring of anemia.TRIAL REGISTRATION. Not applicable.FUNDING. This work was funded by the FDA-funded Atlantic Pediatric Device Consortium, the Georgia Research Alliance, Children’s Healthcare of Atlanta, the Georgia Center of Innovation for Manufacturing, and the InVenture Prize and Ideas to Serve competitions at the Georgia Institute of Technology.Authors
Erika A. Tyburski, Scott E. Gillespie, William A. Stoy, Robert G. Mannino, Alexander J. Weiss, Alexa F. Siu, Rayford H. Bulloch, Karthik Thota, Anyela Cardenas, Wilena Session, Hanna J. Khoury, Siobhán O’Connor, Silvia T. Bunting, Jeanne Boudreaux, Craig R. Forest, Manila Gaddh, Traci Leong, L. Andrew Lyon, Wilbur A. Lam
×Abstract
A maternal diet that is low in protein increases the susceptibility of offspring to type 2 diabetes by inducing long-term alterations in β cell mass and function. Nutrients and growth factor signaling converge through mTOR, suggesting that this pathway participates in β cell programming during fetal development. Here, we revealed that newborns of dams exposed to low-protein diet (LP0.5) throughout pregnancy exhibited decreased insulin levels, a lower β cell fraction, and reduced mTOR signaling. Adult offspring of LP0.5-exposed mothers exhibited glucose intolerance as a result of an insulin secretory defect and not β cell mass reduction. The β cell insulin secretory defect was distal to glucose-dependent Ca2+ influx and resulted from reduced proinsulin biosynthesis and insulin content. Islets from offspring of LP0.5-fed dams exhibited reduced mTOR and increased expression of a subset of microRNAs, and blockade of microRNA-199a-3p and -342 in these islets restored mTOR and insulin secretion to normal. Finally, transient β cell activation of mTORC1 signaling in offspring during the last week of pregnancy of mothers fed a LP0.5 rescued the defect in the neonatal β cell fraction and metabolic abnormalities in the adult. Together, these findings indicate that a maternal low-protein diet alters microRNA and mTOR expression in the offspring, influencing insulin secretion and glucose homeostasis.
Authors
Emilyn U. Alejandro, Brigid Gregg, Taylor Wallen, Doga Kumusoglu, Daniel Meister, Angela Chen, Matthew J. Merrins, Leslie S. Satin, Ming Liu, Peter Arvan, Ernesto Bernal-Mizrachi
×Abstract
Learning and memory deficits are early clinical manifestations of Huntington’s disease (HD). These cognitive impairments have been mainly associated with frontostriatal HD pathology; however, compelling evidence provided by several HD murine models suggests that the hippocampus may contribute to synaptic deficits and memory dysfunction in HD. The neurotrophin receptor p75NTR negatively regulates spine density, which is associated with learning and memory; therefore, we explored whether disturbed p75NTR function in the hippocampus could contribute to synaptic dysfunction and memory deficits in HD. Here, we determined that levels of p75NTR are markedly increased in the hippocampus of 2 distinct mouse models of HD and in HD patients. Normalization of p75NTR levels in HD mutant mice heterozygous for
p75NTR prevented memory and synaptic plasticity deficits and ameliorated dendritic spine abnormalities, likely through normalization of the activity of the GTPase RhoA. Moreover, viral-mediated overexpression of p75NTR in the hippocampus of WT mice reproduced HD learning and memory deficits, while knockdown of p75NTR in the hippocampus of HD mice prevented cognitive decline. Together, these findings provide evidence of hippocampus-associated memory deficits in HD and demonstrate that p75NTR mediates synaptic, learning, and memory dysfunction in HD.Authors
Verónica Brito, Albert Giralt, Lilian Enriquez-Barreto, Mar Puigdellívol, Nuria Suelves, Alfonsa Zamora-Moratalla, Jesús J. Ballesteros, Eduardo D. Martín, Nuria Dominguez-Iturza, Miguel Morales, Jordi Alberch, Sílvia Ginés
×Abstract
Ticks are notorious hematophagous ectoparasites and vectors of many deadly pathogens. As an effective vector, ticks must break the strong barrier provided by the skin of their host during feeding, and their saliva contains a complex mixture of bioactive molecules that paralyze host defenses. The receptor for advanced glycation end products (RAGE) mediates immune cell activation at inflammatory sites and is constitutively and highly expressed in skin. Here, we demonstrate that longistatin secreted with saliva of the tick
Haemaphysalis longicornis binds RAGE and modulates the host immune response. Similar to other RAGE ligands, longistatin specifically bound the RAGE V domain, and stimulated cultured HUVECs adhered to a longistatin-coated surface; this binding was dramatically inhibited by soluble RAGE or RAGE siRNA. Treatment of HUVECs with longistatin prior to stimulation substantially attenuated cellular oxidative stress and prevented NF-κB translocation, thereby reducing adhesion molecule and cytokine production. Recombinant longistatin inhibited RAGE-mediated migration of mouse peritoneal resident cells (mPRCs) and ameliorated inflammation in mouse footpad edema and pneumonia models. Importantly, tick bite upregulated RAGE ligands in skin, and endogenous longistatin attenuated RAGE-mediated inflammation during tick feeding. Our results suggest that longistatin is a RAGE antagonist that suppresses tick bite–associated inflammation, allowing successful blood-meal acquisition from hosts.Authors
Anisuzzaman, Takeshi Hatta, Takeharu Miyoshi, Makoto Matsubayashi, M. Khyrul Islam, M. Abdul Alim, M. Abu Anas, M. Mehedi Hasan, Yasunobu Matsumoto, Yasuhiko Yamamoto, Hiroshi Yamamoto, Kozo Fujisaki, Naotoshi Tsuji
×Abstract
Caspase-3–mediated spontaneous death in neutrophils is a prototype of programmed cell death and is critical for modulating physiopathological inflammatory responses; however, the underlying regulatory pathways remain ill defined. Here we determined that in aging neutrophils, the cleavage and activation of caspase-3 is independent of the canonical caspase-8– or caspase-9–mediated pathway. Instead, caspase-3 activation was mediated by serine protease proteinase 3 (PR3), which is present in the cytosol of aging neutrophils. Specifically, PR3 cleaved procaspase-3 at a site upstream of the canonical caspase-9 cleavage site. In mature neutrophils, PR3 was sequestered in granules and released during aging via lysosomal membrane permeabilization (LMP), leading to procaspase-3 cleavage and apoptosis. Pharmacological inhibition or knockdown of PR3 delayed neutrophil death in vitro and consistently delayed neutrophil death and augmented neutrophil accumulation at sites of inflammation in a murine model of peritonitis. Adoptive transfer of both WT and PR3-deficient neutrophils revealed that the delayed death of neutrophils lacking PR3 is due to an altered intrinsic apoptosis/survival pathway, rather than the inflammatory microenvironment. The presence of the suicide protease inhibitor SERPINB1 counterbalanced the protease activity of PR3 in aging neutrophils, and deletion of
Serpinb1 accelerated neutrophil death. Taken together, our results reveal that PR3-mediated caspase-3 activation controls neutrophil spontaneous death.Authors
Fabien Loison, Haiyan Zhu, Kutay Karatepe, Anongnard Kasorn, Peng Liu, Keqiang Ye, Jiaxi Zhou, Shannan Cao, Haiyan Gong, Dieter E. Jenne, Eileen Remold-O’Donnell, Yuanfu Xu, Hongbo R. Luo
×Heme oxygenase-1 deficiency accompanies neuropathogenesis of HIV-associated neurocognitive disorders
Abstract
Heme oxygenase-1 (HO-1) is an inducible, detoxifying enzyme that is critical for limiting oxidative stress, inflammation, and cellular injury within the CNS and other tissues. Here, we demonstrate a deficiency of HO-1 expression in the brains of HIV-infected individuals. This HO-1 deficiency correlated with cognitive dysfunction, HIV replication in the CNS, and neuroimmune activation. In vitro analysis of HO-1 expression in HIV-infected macrophages, a primary CNS HIV reservoir along with microglia, demonstrated a decrease in HO-1 as HIV replication increased. HO-1 deficiency correlated with increased culture supernatant glutamate and neurotoxicity, suggesting a link among HIV infection, macrophage HO-1 deficiency, and neurodegeneration. HO-1 siRNA knockdown and HO enzymatic inhibition in HIV-infected macrophages increased supernatant glutamate and neurotoxicity. In contrast, increasing HO-1 expression through siRNA derepression or with nonselective pharmacologic inducers, including the CNS-penetrating drug dimethyl fumarate (DMF), decreased supernatant glutamate and neurotoxicity. Furthermore, IFN-γ, which is increased in CNS HIV infection, reduced HO-1 expression in cultured human astrocytes and macrophages. These findings indicate that HO-1 is a protective host factor against HIV-mediated neurodegeneration and suggest that HO-1 deficiency contributes to this degeneration. Furthermore, these results suggest that HO-1 induction in the CNS of HIV-infected patients on antiretroviral therapy could potentially protect against neurodegeneration and associated cognitive dysfunction.
Authors
Alexander J. Gill, Colleen E. Kovacsics, Stephanie A. Cross, Patricia J. Vance, Lorraine L. Kolson, Kelly L. Jordan-Sciutto, Benjamin B. Gelman, Dennis L. Kolson
×Abstract
Liraglutide is a glucagon-like peptide-1 (GLP-1) analog marketed for the treatment of type 2 diabetes. Besides lowering blood glucose, liraglutide also reduces body weight. It is not fully understood how liraglutide induces weight loss or to what degree liraglutide acts directly in the brain. Here, we determined that liraglutide does not activate GLP-1–producing neurons in the hindbrain, and liraglutide-dependent body weight reduction in rats was independent of GLP-1 receptors (GLP-1Rs) in the vagus nerve, area postrema, and paraventricular nucleus. Peripheral injection of fluorescently labeled liraglutide in mice revealed the presence of the drug in the circumventricular organs. Moreover, labeled liraglutide bound neurons within the arcuate nucleus (ARC) and other discrete sites in the hypothalamus. GLP-1R was necessary for liraglutide uptake in the brain, as liraglutide binding was not seen in
Glp1r–/– mice. In the ARC, liraglutide was internalized in neurons expressing proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART). Electrophysiological measurements of murine brain slices revealed that GLP-1 directly stimulates POMC/CART neurons and indirectly inhibits neurotransmission in neurons expressing neuropeptide Y (NPY) and agouti-related peptide (AgRP) via GABA-dependent signaling. Collectively, our findings indicate that the GLP-1R on POMC/CART-expressing ARC neurons likely mediates liraglutide-induced weight loss.Authors
Anna Secher, Jacob Jelsing, Arian F. Baquero, Jacob Hecksher-Sørensen, Michael A. Cowley, Louise S. Dalbøge, Gitte Hansen, Kevin L. Grove, Charles Pyke, Kirsten Raun, Lauge Schäffer, Mads Tang-Christensen, Saurabh Verma, Brent M. Witgen, Niels Vrang, Lotte Bjerre Knudsen
×Abstract
Glioblastoma (GBM) is the most common and lethal brain tumor in adults. Glioma-initiating cells (GICs) are stem-like cells that have been implicated in glioblastoma progression and recurrence; however, the distinct properties of GICs and non-GICs within GBM tumors are largely uncharacterized. Here, we evaluated stem cell–associated microRNA (miR) expression in GICs from GBM patients and GICs derived from xenografted human glioma cell lines and determined that miR-33a promotes GIC growth and self-renewal. Moreover, evaluation of a GBM tissue array revealed that higher miR-33a expression was associated with poor prognosis of GBM patients. Antagonizing miR-33a function in GICs reduced self-renewal and tumor progression in immune-compromised mice, whereas overexpression of miR-33a in non-GICs promoted the display of features associated with GICs. We identified the mRNAs encoding phosphodiesterase 8A (PDE8A) and UV radiation resistance–associated gene (UVRAG) as direct miR-33a targets. PDE8A and UVRAG negatively regulated the cAMP/PKA and NOTCH pathways, respectively; therefore, miR-33a–dependent reduction of these proteins promoted growth and self-renewal of GICs by enhancing PKA and NOTCH activity. Furthermore, in GBM specimens, there was an inverse correlation between the expression levels of miR-33a and
PDE8A andUVRAG expression. These findings reveal a miR-33a–centered signaling network that promotes GIC maintenance and has potential as a therapeutic target for GBM treatment.Authors
Hui Wang, Tao Sun, Jing Hu, Rui Zhang, Yanhua Rao, Shuai Wang, Rui Chen, Roger E. McLendon, Allan H. Friedman, Stephen T. Keir, Darell D. Bigner, Qi-Jing Li, Huibo Wang, Xiao-Fan Wang
×Abstract
In humans, vWF levels predict the risk of myocardial infarction and thrombosis; however, the factors that influence vWF levels are not completely understood. Recent genome-wide association studies (GWAS) have identified syntaxin-binding protein 5 (
STXBP5 ) as a candidate gene linked to changes in vWF plasma levels, though the functional relationship betweenSTXBP5 and vWF is unknown. We hypothesized that STXBP5 inhibits endothelial cell exocytosis. We found that STXBP5 is expressed in human endothelial cells and colocalizes with and interacts with syntaxin 4. In human endothelial cells reduction of STXBP5 increased exocytosis of vWF and P-selectin. Mice lackingStxbp5 had higher levels of vWF in the plasma, increased P-selectin translocation, and more platelet-endothelial interactions, which suggests that STXBP5 inhibits endothelial exocytosis. However,Stxbp5 KO mice also displayed hemostasis defects, including prolonged tail bleeding times and impaired mesenteric arteriole and carotid artery thrombosis. Furthermore, platelets fromStxbp5 KO mice had defects in platelet secretion and activation; thus, STXBP5 inhibits endothelial exocytosis but promotes platelet secretion. Our study reveals a vascular function for STXBP5, validates the functional relevance of a candidate gene identified by GWAS, and suggests that variation withinSTXBP5 is a genetic risk for venous thromboembolic disease.Authors
Qiuyu Zhu, Munekazu Yamakuchi, Sara Ture, Maria de la Luz Garcia-Hernandez, Kyung Ae Ko, Kristina L. Modjeski, Michael B. LoMonaco, Andrew D. Johnson, Christopher J. O’Donnell, Yoshimi Takai, Craig N. Morrell, Charles J. Lowenstein
×Abstract
Genome-wide association studies (GWAS) have linked genes encoding several soluble NSF attachment protein receptor (SNARE) regulators to cardiovascular disease risk factors. Because these regulatory proteins may directly affect platelet secretion, we used SNARE-containing complexes to affinity purify potential regulators from human platelet extracts. Syntaxin-binding protein 5 (STXBP5; also known as tomosyn-1) was identified by mass spectrometry, and its expression in isolated platelets was confirmed by RT-PCR analysis. Coimmunoprecipitation studies showed that STXBP5 interacts with core secretion machinery complexes, such as syntaxin-11/SNAP23 heterodimers, and fractionation studies suggested that STXBP5 also interacts with the platelet cytoskeleton. Platelets from
Stxbp5 KO mice had normal expression of other key secretory components; however, stimulation-dependent secretion from each of the 3 granule types was markedly defective. Secretion defects in STXBP5-deficient platelets were confirmed via lumi-aggregometry and FACS analysis for P-selectin and LAMP-1 exposure. Interestingly, STXBP5-deficient platelets had altered granule cargo levels, despite having normal morphology and granule numbers. Consistent with secretion and cargo deficiencies,Stxbp5 KO mice showed dramatic bleeding in the tail transection model and defective hemostasis in the FeCl3-induced carotid injury model. Transplantation experiments indicated that these defects were due to loss of STXBP5 in BM-derived cells. Our data demonstrate that STXBP5 is required for normal arterial hemostasis, due to its contributions to platelet granule cargo packaging and secretion.Authors
Shaojing Ye, Yunjie Huang, Smita Joshi, Jinchao Zhang, Fanmuyi Yang, Guoying Zhang, Susan S. Smyth, Zhenyu Li, Yoshimi Takai, Sidney W. Whiteheart
×Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a nonmalignant clonal disease of hematopoietic stem cells that is associated with hemolysis, marrow failure, and thrombophilia. PNH has been considered a monogenic disease that results from somatic mutations in the gene encoding PIGA, which is required for biosynthesis of glycosylphosphatidylinisotol-anchored (GPI-anchored) proteins. The loss of certain GPI-anchored proteins is hypothesized to provide the mutant clone with an extrinsic growth advantage, but some features of PNH argue that there are intrinsic drivers of clonal expansion. Here, we performed whole-exome sequencing of paired PNH+ and PNH– fractions on samples taken from 12 patients as well as targeted deep sequencing of an additional 36 PNH patients. We identified additional somatic mutations that resulted in a complex hierarchical clonal architecture, similar to that observed in myeloid neoplasms. In addition to mutations in
PIGA , mutations were found in genes known to be involved in myeloid neoplasm pathogenesis, includingTET2 ,SUZ12 ,U2AF1 , andJAK2 . Clonal analysis indicated that these additional mutations arose either as a subclone within thePIGA -mutant population, or prior toPIGA mutation. Together, our data indicate that in addition toPIGA mutations, accessory genetic events are frequent in PNH, suggesting a stepwise clonal evolution derived from a singular stem cell clone.Authors
Wenyi Shen, Michael J. Clemente, Naoko Hosono, Kenichi Yoshida, Bartlomiej Przychodzen, Tetsuichi Yoshizato, Yuichi Shiraishi, Satoru Miyano, Seishi Ogawa, Jaroslaw P. Maciejewski, Hideki Makishima
×Abstract
Papillon-Lefèvre syndrome (PLS) results from mutations that inactivate cysteine protease cathepsin C (CTSC), which processes a variety of serine proteases considered essential for antimicrobial defense. Despite serine protease–deficient immune cell populations, PLS patients do not exhibit marked immunodeficiency. Here, we characterized a 24-year-old woman who had suffered from severe juvenile periodontal disease, but was otherwise healthy, and identified a homozygous missense mutation in
CTSC indicative of PLS. Proteome analysis of patient neutrophil granules revealed that several proteins that normally localize to azurophil granules, including the major serine proteases, elastase, cathepsin G, and proteinase 3, were absent. Accordingly, neutrophils from this patient were incapable of producing neutrophil extracellular traps (NETs) in response to ROS and were unable to process endogenous cathelicidin hCAP-18 into the antibacterial peptide LL-37 in response to ionomycin. In immature myeloid cells from patient bone marrow, biosynthesis of CTSC and neutrophil serine proteases appeared normal along with initial processing and sorting to cellular storage. In contrast, these proteins were completely absent in mature neutrophils, indicating thatCTSC mutation promotes protease degradation in more mature hematopoietic subsets, but does not affect protease production in progenitor cells. Together, these data indicate CTSC protects serine proteases from degradation in mature immune cells and suggest that neutrophil serine proteases are dispensable for human immunoprotection.Authors
Ole E. Sørensen, Stine N. Clemmensen, Sara L. Dahl, Ole Østergaard, Niels H. Heegaard, Andreas Glenthøj, Finn Cilius Nielsen, Niels Borregaard
×Abstract
Calcium signaling is critical for lymphocyte function, and intracellular Ca2+ concentrations are regulated by store-operated Ca2+ entry (SOCE) through Ca2+ release–activated Ca2+ (CRAC) channels. In patients, loss-of-function mutations in CRAC channel components
ORAI1 andSTIM1 abolish SOCE and are associated with recurrent and chronic viral infections. Here, using mice with conditional deletion ofStim1 and its homologStim2 in T cells, we determined that both components are required for the maintenance of virus-specific memory CD8+ T cells and recall responses following secondary infection. In the absence of STIM1 and STIM2, acute viral infections became chronic. Early during infection, STIM1 and STIM2 were required for the differentiation of naive CD8+ T cells into fully functional cytolytic effector cells and mediated the production of cytokines and prevented cellular exhaustion in viral-specific CD8+ effector T cells. Importantly, memory and recall responses by CD8+ T cells required expression of STIM1 and STIM2 in CD4+ T cells. CD4+ T cells lacking STIM1 and STIM2 were unable to provide “help” to CD8+ T cells due to aberrant regulation of CD40L expression. Together, our data indicate that STIM1, STIM2, and CRAC channel function play distinct but synergistic roles in CD4+ and CD8+ T cells during antiviral immunity.Authors
Patrick J. Shaw, Carl Weidinger, Martin Vaeth, Kevin Luethy, Susan M. Kaech, Stefan Feske
×Abstract
Retinal and choroidal neovascularization (NV) and vascular leakage contribute to visual impairment in several common ocular diseases. The angiopoietin/TIE2 (ANG/TIE2) pathway maintains vascular integrity, and negative regulators of this pathway are potential therapeutic targets for these diseases. Here, we demonstrated that vascular endothelial-protein tyrosine phosphatase (VE-PTP), which negatively regulates TIE2 activation, is upregulated in hypoxic vascular endothelial cells, particularly in retinal NV. Intraocular injection of an anti–VE-PTP antibody previously shown to activate TIE2 suppressed ocular NV. Furthermore, a small-molecule inhibitor of VE-PTP catalytic activity (AKB-9778) activated TIE2, enhanced ANG1-induced TIE2 activation, and stimulated phosphorylation of signaling molecules in the TIE2 pathway, including AKT, eNOS, and ERK. In mouse models of neovascular age-related macular degeneration, AKB-9778 induced phosphorylation of TIE2 and strongly suppressed NV. Ischemia-induced retinal NV, which is relevant to diabetic retinopathy, was accentuated by the induction of ANG2 but inhibited by AKB-9778, even in the presence of high levels of ANG2. AKB-9778 also blocked VEGF-induced leakage from dermal and retinal vessels and prevented exudative retinal detachments in double-transgenic mice with high expression of VEGF in photoreceptors. These data support targeting VE-PTP to stabilize retinal and choroidal blood vessels and suggest that this strategy has potential for patients with a wide variety of retinal and choroidal vascular diseases
Authors
Jikui Shen, Maike Frye, Bonnie L. Lee, Jessica L. Reinardy, Joseph M. McClung, Kun Ding, Masashi Kojima, Huiming Xia, Christopher Seidel, Raquel Lima e Silva, Aling Dong, Sean F. Hackett, Jiangxia Wang, Brian W. Howard, Dietmar Vestweber, Christopher D. Kontos, Kevin G. Peters, Peter A. Campochiaro
×Abstract
Controlling the overwhelming inflammatory reaction associated with polymicrobial sepsis remains a prevalent clinical challenge with few treatment options. In septic peritonitis, blood neutrophils and monocytes are rapidly recruited into the peritoneal cavity to control infection, but the role of resident sentinel cells during the early phase of infection is less clear. In particular, the influence of mast cells on other tissue-resident cells remains poorly understood. Here, we developed a mouse model that allows both visualization and conditional ablation of mast cells and basophils to investigate the role of mast cells in severe septic peritonitis. Specific depletion of mast cells led to increased survival rates in mice with acute sepsis. Furthermore, we determined that mast cells impair the phagocytic action of resident macrophages, thereby allowing local and systemic bacterial proliferation. Mast cells did not influence local recruitment of neutrophils and monocytes or the release of inflammatory cytokines. Phagocytosis inhibition by mast cells involved their ability to release prestored IL-4 within 15 minutes after bacterial encounter, and treatment with an IL-4–neutralizing antibody prevented this inhibitory effect and improved survival of septic mice. Our study uncovers a local crosstalk between mast cells and macrophages during the early phase of sepsis development that aggravates the outcome of severe bacterial infection.
Authors
Albert Dahdah, Gregory Gautier, Tarik Attout, Frédéric Fiore, Emeline Lebourdais, Rasha Msallam, Marc Daëron, Renato C. Monteiro, Marc Benhamou, Nicolas Charles, Jean Davoust, Ulrich Blank, Bernard Malissen, Pierre Launay
×Abstract
After internalization, transmembrane receptors (TMRs) are typically recycled back to the cell surface or targeted for degradation. Efficient TMR trafficking is critical for regulation of several processes, including signal transduction pathways, development, and disease. Here, we determined that trafficking of the angiogenic receptor neuropilin-1 (NRP-1) is abrogated by the liver kinase B1 (LKB1), a serine-threonine kinase of the calcium calmodulin family. We found that aberrant NRP-1 expression in tumor cells from patients with lung adenocarcinoma is associated with decreased levels of LKB1. In cultured lung cells, LKB1 accentuated formation of a complex between NRP-1 and RAB7 in late endosomes. LKB1 specifically bound GTP-bound RAB7, but not a dominant-negative GDP-bound form of RAB7, promoting rapid transfer and lysosome degradation of NRP-1. siRNA-mediated depletion of RAB7 disrupted the transfer of NRP-1 to the lysosome, resulting in recovery of the receptor as well as increased tumor growth and angiogenesis. Together, our findings indicate that LKB1 functions as a RAB7 effector and suppresses angiogenesis by promoting the cellular trafficking of NRP-1 from RAB7 vesicles to the lysosome for degradation. Furthermore, these data suggest that LKB1 and NRP-1 have potential as therapeutic targets for limiting tumorigenesis.
Authors
Imoh S. Okon, Kathleen A. Coughlan, Cheng Zhang, Cate Moriasi, Ye Ding, Ping Song, Wencheng Zhang, Guangpu Li, Ming-Hui Zou
×Abstract
Regulatory T cells (Tregs), which express CD4 and FOXP3, are critical for modulating the immune response and promoting immune tolerance. Consequently, methods to expand Tregs for therapeutic use are of great interest. While transfer of Tregs after massive ex vivo expansion can be achieved, in vivo expansion of Tregs would be more practical. Here, we demonstrate that targeting the CD45 tyrosine phosphatase with a tolerogenic anti-CD45RB mAb acutely increases Treg numbers in WT mice, even in absence of exogenous antigen. Treg expansion occurred through substantial augmentation of homeostatic proliferation in the preexisting Treg population. Moreover, anti-CD45RB specifically increased Treg proliferation in response to cognate antigen. Compared with conventional T cells, Tregs differentially regulate their conjugation with DCs. Therefore, we determined whether CD45 ligation could alter interactions between Tregs and DCs. Live imaging showed that CD45 ligation specifically reduced Treg motility in an integrin-dependent manner, resulting in enhanced interactions between Tregs and DCs in vivo. Increased conjugate formation, in turn, augmented nuclear translocation of nuclear factor of activated T cells (NFAT) and Treg proliferation. Together, these results demonstrate that Treg peripheral homeostasis can be specifically modulated in vivo to promote Treg expansion and tolerance by increasing conjugation between Tregs and DCs.
Authors
Geoffrey Camirand, Ying Wang, Yuning Lu, Yisong Y. Wan, Yan Lin, Songyan Deng, Galip Guz, David L. Perkins, Patricia W. Finn, Donna L. Farber, Richard A. Flavell, Warren D. Shlomchik, Fadi G. Lakkis, Christopher E. Rudd, David M. Rothstein
×Abstract
Ovarian cancer (OvCa) metastasizes to organs in the abdominal cavity, such as the omentum, which are covered by a single layer of mesothelial cells. Mesothelial cells are generally thought to be “bystanders” to the metastatic process and simply displaced by OvCa cells to access the submesothelial extracellular matrix. Here, using organotypic 3D cultures, we found that primary human mesothelial cells secrete fibronectin in the presence of OvCa cells. Moreover, we evaluated the tumor stroma of 108 human omental metastases and determined that fibronectin was consistently overexpressed in these patients. Blocking fibronectin production in primary mesothelial cells in vitro or in murine models, either genetically (fibronectin 1 floxed mouse model) or via siRNA, decreased adhesion, invasion, proliferation, and metastasis of OvCa cells. Using a coculture model, we determined that OvCa cells secrete TGF-β1, which in turn activates a TGF-β receptor/RAC1/SMAD-dependent signaling pathway in the mesothelial cells that promotes a mesenchymal phenotype and transcriptional upregulation of fibronectin. Additionally, blocking α5 or β1 integrin function with antibodies reduced metastasis in an orthotopic preclinical model of OvCa metastasis. These findings indicate that cancer-associated mesothelial cells promote colonization during the initial steps of OvCa metastasis and suggest that mesothelial cells actively contribute to metastasis.
Authors
Hilary A. Kenny, Chun-Yi Chiang, Erin A. White, Elizabeth M. Schryver, Mohammed Habis, Iris L. Romero, Andras Ladanyi, Carla V. Penicka, Joshy George, Karl Matlin, Anthony Montag, Kristen Wroblewski, S. Diane Yamada, Andrew P. Mazar, David Bowtell, Ernst Lengyel
×Abstract
Parkinson’s disease (PD) is the most prevalent hypokinetic movement disorder, and symptomatic PD pathogenesis has been ascribed to imbalances between the direct and indirect pathways in the basal ganglia circuitry. Here, we applied glutamate receptor blockers to the subthalamic nucleus (STN) of parkinsonian rats and evaluated locomotor behaviors via single-unit and local-field recordings. Using this model, we found that inhibition of NMDAergic cortico-subthalamic transmission ameliorates parkinsonian motor deficits without eliciting any vivid turning behavior and abolishes electrophysiological abnormalities, including excessive subthalamic bursts, cortico-subthalamic synchronization, and in situ beta synchronization in both the motor cortex and STN. Premotor cortex stimulation revealed that cortico-subthalamic transmission is deranged in PD and directly responsible for the excessive stimulation-dependent bursts and time-locked spikes in the STN, explaining the genesis of PD-associated pathological bursts and synchronization, respectively. Moreover, application of a dopaminergic agent via a microinfusion cannula localized the therapeutic effect to the STN, without correcting striatal dopamine deficiency. Finally, optogenetic overactivation and synchronization of cortico-subthalamic transmission alone sufficiently and instantaneously induced parkinsonian-associated locomotor dysfunction in normal mice. In addition to the classic theory emphasizing the direct-indirect pathways, our data suggest that deranged cortico-subthalamic transmission via the NMDA receptor also plays a central role in the pathophysiology of parkinsonian motor deficits.
Authors
Ming-Kai Pan, Chun-Hwei Tai, Wen-Chuan Liu, Ju-Chun Pei, Wen-Sung Lai, Chung-Chin Kuo
×Abstract
Oxidative damage and inflammation are both implicated in the genesis of hypertension; however, the mechanisms by which these stimuli promote hypertension are not fully understood. Here, we have described a pathway in which hypertensive stimuli promote dendritic cell (DC) activation of T cells, ultimately leading to hypertension. Using multiple murine models of hypertension, we determined that proteins oxidatively modified by highly reactive γ-ketoaldehydes (isoketals) are formed in hypertension and accumulate in DCs. Isoketal accumulation was associated with DC production of IL-6, IL-1β, and IL-23 and an increase in costimulatory proteins CD80 and CD86. These activated DCs promoted T cell, particularly CD8+ T cell, proliferation; production of IFN-γ and IL-17A; and hypertension. Moreover, isoketal scavengers prevented these hypertension-associated events. Plasma F2-isoprostanes, which are formed in concert with isoketals, were found to be elevated in humans with treated hypertension and were markedly elevated in patients with resistant hypertension. Isoketal-modified proteins were also markedly elevated in circulating monocytes and DCs from humans with hypertension. Our data reveal that hypertension activates DCs, in large part by promoting the formation of isoketals, and suggest that reducing isoketals has potential as a treatment strategy for this disease.
Authors
Annet Kirabo, Vanessa Fontana, Ana P.C. de Faria, Roxana Loperena, Cristi L. Galindo, Jing Wu, Alfiya T. Bikineyeva, Sergey Dikalov, Liang Xiao, Wei Chen, Mohamed A. Saleh, Daniel W. Trott, Hana A. Itani, Antony Vinh, Venkataraman Amarnath, Kalyani Amarnath, Tomasz J. Guzik, Kenneth E. Bernstein, Xiao Z. Shen, Yu Shyr, Sheau-chiann Chen, Raymond L. Mernaugh, Cheryl L. Laffer, Fernando Elijovich, Sean S. Davies, Heitor Moreno, Meena S. Madhur, Jackson Roberts II, David G. Harrison
×Abstract
Classical IL-22–producing T helper cells (Th22 cells) mediate inflammatory responses independently of IFN-γ and IL-17; however, nonclassical Th22 cells have been recently identified and coexpress IFN-γ and/or IL-17 along with IL-22. Little is known about how classical and nonclassical Th22 subsets in human diseases are regulated. Here, we used samples of human blood, normal and peritumoral liver, and hepatocellular carcinoma (HCC) to delineate the phenotype, distribution, generation, and functional relevance of various Th22 subsets. Three nonclassical Th22 subsets constituted the majority of all Th22 cells in human liver and HCC tissues, although the classical Th22 subset was predominant in blood. Monocytes activated by TLR2 and TLR4 agonists served as the antigen-presenting cells (APCs) that most efficiently triggered the expansion of nonclassical Th22 subsets from memory T cells and classical Th22 subsets from naive T cells. Moreover, B7-H1–expressing monocytes skewed Th22 polarization away from IFN-γ and toward IL-17 through interaction with programmed death 1 (PD-1), an effect that can create favorable conditions for in vivo aggressive cancer growth and angiogenesis. Our results provide insight into the selective modulation of Th22 subsets and suggest that strategies to influence functional activities of inflammatory cells may benefit anticancer therapy.
Authors
Dong-Ming Kuang, Xiao Xiao, Qiyi Zhao, Min-Min Chen, Xue-Feng Li, Rui-Xian Liu, Yuan Wei, Fang-Zhu Ouyang, Dong-Ping Chen, Yan Wu, Xiang-Ming Lao, Hong Deng, Limin Zheng
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)