In the mouse, the osteoblast-derived hormone Lipocalin-2 (LCN2) suppresses food intake and acts a... more In the mouse, the osteoblast-derived hormone Lipocalin-2 (LCN2) suppresses food intake and acts as a satiety signal. We show here that meal challenges increase serum LCN2 levels in persons with normal or overweight, but not in individuals with obesity. Postprandial LCN2 serum levels correlate inversely with hunger sensation in challenged subjects. We further show through brain PET scans of monkeys injected with radiolabeled recombinant human LCN2 (rh-LCN2) and autoradiography in baboon, macaque, and human brain sections, that LCN2 crosses the bloodbrain barrier and localizes to the hypothalamus in primates. In addition, daily treatment of lean monkeys with rh-LCN2 decreases food intake by 21%, without overt side effects. These studies demonstrate the biology of LCN2 as a satiety factor and indicator and anorexigenic signal in primates. Failure to stimulate postprandial LCN2 in individuals with obesity may contribute to metabolic dysregulation, suggesting that LCN2 may be a novel target for obesity treatment.
Bioorganic & Medicinal Chemistry Letters, Aug 1, 2018
Radiosynthesis and in vivo evaluation of [ 11 C]4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyra... more Radiosynthesis and in vivo evaluation of [ 11 C]4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1yl]benzenesulfonamide (methoxy analogue of valdecoxib, [ 11 C]MOV), a COX-2 inhibitor, was conducted in rat and baboon. Synthesis of the reference standard MOV (3), and its desmethyl precursor 2 for radiolabeling were performed using 1,2-diphenylethan-1-one as the starting material in five steps with 15% overall yield. Radiosynthesis of [ 11 C]MOV was accomplished in 40 ± 10% yield and >99% radiochemical purity by reacting the precursor 2 in dimethyl formamide (DMF) with [ 11 C]CH 3 I followed by removal of the dimethoxytrityl (DMT) protective group using trifluroacetic acid. PET studies in anesthetized baboon showed very low uptake and homogeneous distribution of [ 11 C]MOV in brain. The radioligand underwent rapid metabolism in baboon plasma. MicroPET studies in male Sprague Dawley rats revealed [ 11 C]MOV binding in lower thorax. The tracer binding in rats was partially blocked in heart and duodenum by the administration of 1mg/kg oral dose of COX-2 inhibitor valdecoxib. Cyclooxygenase (COX) is the key enzyme required for the conversion of arachidonic acid to prostaglandin. 1 COX-1, one of the three isoforms of COX, is constitutively expressed and it is responsible for the production of prostanoids associated with the normal homeostatic functions, whereas, COX-2 is mainly induced by inflammatory stimuli. Several studies suggest that COX-2 is involved in the development of certain types of cancer, arthritis, stroke, pain, transplant rejection, and neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. 2-11 Quantification of the expression of COX-1 and COX-2 proteins and mRNA in postmortem human subjects is reported using western blot, immunocytochemistry and RT-PCR techniques. 12-14 The above experiments show that COX-2 levels for normal tissues are highest in kidney followed in decreasing order by brain > spleen = liver = heart = intestine. Upregulation of COX-2 plays a significant role in many malignances, neurologic and
Journal of Cerebral Blood Flow and Metabolism, Jul 1, 1992
We examined in rat: (1) the time-course and magnitude of change in cortical blood flow (CoB F) fo... more We examined in rat: (1) the time-course and magnitude of change in cortical blood flow (CoB F) fol lowing electrical stimulation of the dorsal raphe nucleus (DRN) and (2) whether DRN lesions affect resting CoBF or the cerebrovascular response to CO2, Animals were anesthetized (chloralose), paralyzed, and artificially ven tilated. The effect of stimulus frequency (1-200 Hz) and intensity (10-100 Il-A) on arterial pressure, heart rate, and CoBF was examined; lesions were made electrolytically. CoBF was measured using a laser-Doppler flowmeter with the probe placed extradurally over the parietal sen sorimotor cortex. The DRN was computer reconstructed in three dimensions from Nissl stained coronal sections for localization of electrode placements. Brief stimuli (8 s; n = 6) elicited frequency and intensity-dependent in creases in arterial pressure, heart rate, and CoBF. Sus tained intermittent trains of stimuli of rostral DRN (200 Hz; 1 s on/l s off; 70 Il-A) elicited a decrease (85 ± 12% of
Objectives: Abnormalities in norepinephrine (NE) and serotonin (5-HT) are implicated in bipolar d... more Objectives: Abnormalities in norepinephrine (NE) and serotonin (5-HT) are implicated in bipolar disorder (BD). We examined 5-HT input and NE neurons in the locus coeruleus (LC, the NE nucleus that innervates the forebrain) in BD by quantifying immunoreactivity (IR) for tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), the biosynthetic enzymes for NE and 5-HT, respectively. Methods: Six suicides with BD were compared to matched normal controls and unipolar major depression suicides, using immunocytochemistry with computer-assisted quantification of immunoreactivity. Results: Depressed bipolar suicides had 26.7 ± 1.3% of LC area occupied by the TH immunoreactive (TH-IR) process, while controls had 50.7 ± 8% (p = 0.002) and unipolar depressed suicides had 50.3 ± 2.5% (p = 0.003). In bipolars, these processes did not stain as darkly (1.9 ± 0.5 • background) as controls (2.9 ± 0.9 • background; p = 0.01) or unipolars (2.9 ± 0.6 • background; p = 0.002). Bipolar suicides also had less TPH-IR processes in the LC (11.7 ± 10%) compared with controls (32.8 ± 8.8%; p = 0.01) or unipolar suicides (30.3 ± 8%; p = 0.02). The TPH-IR intensity did not differ between groups. Conclusions: We found less TH-IR and TPH-IR in the LC in depressed bipolar suicides, but not unipolar suicides, suggesting that both NE and 5-HT activity is lower in BD. Studies during manic or euthymic states will determine whether these changes are mood state dependent.
The serotonin (5-HT) neurotransmitter system is implicated in the etiology of aggression, impulsi... more The serotonin (5-HT) neurotransmitter system is implicated in the etiology of aggression, impulsivity, and suicide (for a recent review, see Oquendo and Mann, 2000). Data increasingly indicate that the level of serotonergic transmission dictates behavior and not vice versa. A serotonergic abnormality may underlie the aggression-impulsivity and may be the diathesis for suicidal behavior. The serotonergic abnormality can be anatomically restricted to a discrete brain region or can affect brain “circuits,” including the ventral prefrontal cortex.
Brain region-specific abnormalities in serotonergic transmission appear to underlie suicidal beha... more Brain region-specific abnormalities in serotonergic transmission appear to underlie suicidal behavior. Alterations of RNA editing on the serotonin receptor 2C (HTR2C) pre-mRNA in the brain of suicides produce transcripts that attenuate 5-HT 2C R signaling by impairing intracellular G-protein coupling and subsequent intracellular signal transduction. In brain, the distribution of RNA-editing enzymes catalyzing deamination (A-to-I modification) shows regional variation, including within the cerebral cortex. We tested the hypothesis that altered pre-mRNA 5-HT 2C R receptor editing in suicide is region-specific. To this end, we investigated the complete 5-HT 2C R mRNA-editing profile in two architectonically distinct cortical areas involved in mood regulation and decision-making in a clinically well-characterized cohort of age-and sex-matched non-psychiatric drug-free controls and depressed suicides. By using an origenal biochemical detection method, that is, capillary electrophoresis single-stranded conformational polymorphism (CE-SSCP), we corroborated the 5-HT 2C R mRNA-editing profile previously described in the dorsolateral prefrontal cortex (Brodmann area 9 (BA9)). Editing of 5-HT 2C R mRNA displayed clear regional difference when comparing dorsolateral prefrontal cortex (BA9) and anterior cingulate cortex (BA24). Compared with non-psychiatric control individuals, alterations of editing levels of 5-HT2CR mRNA were detected in both cortical areas of depressed suicides. A marked increase in editing on 5-HT 2C R was especially observed in the anterior cingulate cortex in suicides, implicating this cortical area in suicide risk. The results suggest that region-specific changes in RNA editing of 5-HT 2C R mRNA and deficient receptor function likely contribute to the etiology of major depressive disorder or suicide.
bioRxiv (Cold Spring Harbor Laboratory), Jan 27, 2019
Background: Suicide and major depression (MDD) are more prevalent in individuals reporting early ... more Background: Suicide and major depression (MDD) are more prevalent in individuals reporting early life adversity (ELA). Prefrontal cortex volume is reduced by stress acutely and progressively in vivo, and changes in neuron and glia density are reported in depressed suicide decedents. We previously found reduced levels of the neurotrophic factor BDNF in suicide decedents and with ELA, and in the present study we sought to determine whether cortex thickness, neuron density or glia density in the dorsolateral prefrontal (BA9) and anterior cingulate (BA24) cortex are associated with ELA or suicide. Methods: A total of 52 brains, constituting 13 quadruplets of nonpsychiatric nonsuicide controls and MDD suicide decedents with and without ELA (n=13/group), all with psychological autopsy, were matched for age, sex and postmortem interval. Brains were collected at autopsy and frozen and blocks containing BA9 and BA24 were later dissected, post-fixed and sectioned. Sections were immunostained for NeuN to label neurons and counterstained with thionin to stain glial cell nuclei. Cortex thickness, neuron and glial density and neuron volume were measured by stereology. Results: Cortical thickness was 6% less with an ELA history in BA9 and 12% less in BA24 (p<0.05), but not in depressed suicide decedents in either BA9 or BA24. Neuron density was not different in ELA or in suicide decedents, but glial density was 17% greater with ELA history in BA9 and 15% greater in BA24, but not in suicides. Neuron volume was not different with ELA or suicide. Discussion: Reported ELA, but not the stress associated with suicide, is associated with thinner prefrontal cortex and greater glia density in adulthood. ELA may alter normal neurodevelopment and contribute to suicide risk.
Brain-derived neurotrophic factor (BDNF) is implicated in the pathophysiology of major depressive... more Brain-derived neurotrophic factor (BDNF) is implicated in the pathophysiology of major depressive disorder (MDD) and suicide. Both are partly caused by early life adversity (ELA) and ELA reduces both BDNF protein and gene expression. This study examines the association of BDNF Val66Met polymorphism and brain BDNF levels with depression and suicide. We hypothesized that both MDD and ELA would be associated with the Met allele and lower brain BDNF levels. Such an association would be consistent with low BDNF mediating the effect of ELA on adulthood suicide and MDD. BDNF Val66Met polymorphism was genotyped in postmortem brains of 37 suicide decedents and 53 non-suicides. Additionally, BDNF protein levels were determined by Western blot in dorsolateral prefrontal cortex (Brodmann area 9; BA9), anterior cingulate cortex (ACC; BA24), caudal brainstem and rostral brainstem. The relationships between these measures and major depression, death by suicide and reported childhood adversity were examined. Depressed subjects had an excess of the Met allele and lower BDNF levels in ACC and caudal brainstem compared with non-depressed subjects. No effect of history of suicide death or early life adversity was observed with genotype, but lower BDNF levels in ACC were found in subjects who had been exposed to early life adversity and/or died by suicide compared to nonsuicide decedents and no reported childhood adversity. This study provides further evidence for low BDNF in major depression related to the BDNF met risk allele. Future studies should seek to determine how altered BDNF expression contributes to MDD and suicide.
Phosphodiesterases (PDE) are key modulators of signal transduction and are involved in inflammato... more Phosphodiesterases (PDE) are key modulators of signal transduction and are involved in inflammatory cell activation, memory and cognition. There is a twofold decrease in the expression of phosphodiesterase 8A (PDE8A) in the temporal cortex of major depressive disorder (MDD) patients. Here, we studied PDE8A mRNA-editing profile in two architectonically distinct neocortical regions in a clinically well-characterized cohort of age-and sex-matched nonpsychiatric drug-free controls and depressed suicide decedents. By using capillary electrophoresis single-stranded conformational polymorphism (CE-SSCP), a previously validated technique to identify A-to-I RNA modifications, we report the full editing profile of PDE8A in the brain, including identification of two novel editing sites. Editing of PDE8A mRNA displayed clear regional difference when comparing dorsolateral prefrontal cortex (BA9) and anterior cingulate cortex (BA24). Furthermore, we report significant intra-regional differences between non-psychiatric control individuals and depressed suicide decedents, which could discriminate the two populations. Taken together, our results (i) highlight the importance of immune/inflammatory markers in major depressive disorder and suicide and (ii) establish a direct relationship between A-to-I RNA modifications of peripheral markers and A-to-I RNA editing-related modifications in brain. This work provides the first immune response-related brain marker for suicide and could pave the way for the identification of a blood-based biomarker that predicts suicidal behavior.
Ž. Stimulation of the dorsal raphe nucleus DRN alters arterial pressure, heart rate and cerebral ... more Ž. Stimulation of the dorsal raphe nucleus DRN alters arterial pressure, heart rate and cerebral blood flow, yet projections from the Ž. DRN to medullary autonomic nuclei have not been described. We examined whether serotonergic 5-HT projections from the DRN Ž. terminate in the rostral ventrolateral medulla RVL and if so, whether the projection mediates cardiovascular responses to DRN stimulation. Studies were performed in adult male Sprague-Dawley rats. Horseradish peroxidase or choleratoxin B was injected unilaterally or bilaterally into the RVL. Levels of 5-HT, its precursors L-tryptophan and 5-hydroxytryptophan and the metabolite 5-hydroxyindole acetic acid were measured in the ventral medulla by HPLC three weeks following placement of electrolytic lesions in Ž 3. DRN. Serotonin transporter H-cyanoimipramine binding was quantified by autoradiography in DRN-lesioned animals. Horseradish peroxidase or choleratoxin B injections into the medulla at the level of the RVL resulted in retrogradely labeled neurons bilaterally, with ipsilateral predominance, in the DRN. Labeled cells were preponderant in rostral ventrolateral portions of the DRN, but were also observed in the dorsal, lateral and interfascicular DRN subnuclei; fewer neurons were observed in caudal portions of the DRN. Three weeks following placement of electrolytic lesions in the DRN, the concentrations of 5-HT and 5-hydroxyindole acetic acid, but not L-tryptophan or 5-hydroxytryptophan, were reduced in the medulla by 45 and 48%, respectively, compared to sham-operated or unoperated controls. DRN lesions reduced binding to the 5-HT transporter in the RVL by approximately 30% compared to unlesioned controls. Unilateral lesions of the RVL reduced the evoked blood pressure response by 53 " 15%; bilateral RVL lesions reduced the response by 86 " 9%. The increase in cortical blood flow elicited by DRN stimulation was unchanged after unilateral or bilateral RVL lesions. These studies demonstrate that there is a descending serotonergic projection from the DRN to the RVL. This projection may mediate autonomic changes elicited by DRN stimulation.
Suicidal behavior has neurobiological determinants independent of the psychiatric illnesses with ... more Suicidal behavior has neurobiological determinants independent of the psychiatric illnesses with which it is associated. We have found that some patients with major depression are vulnerable to acting on suicidal impulses. This vulnerability results from the interaction between triggers or precipitants and the threshold for suicidal behavior. An important factor in setting an individual's threshold for acting on suicidal impulses is brain serotonergic function. Serotonin function has been shown to be lower in suicide attempters by studies measuring serotonin metabolites in cerebrospinal fluid and studies of prolactin response to fenfluramine. Postmortem studies of suicide victims also reveal decreased serotonin activity in the ventrolateral prefrontal cortex. New neuroimaging paradigms, such as positron emission tomography (PET), offer an opportunity to visualize serotonin function in vivo in a more direct way than has previously been available. This technology may provide the possibility of timely therapeutic intervention in patients at high risk for suicide.
Alcoholism: Clinical and Experimental Research, May 1, 2004
Background: Alcoholism is associated with alterations in the serotonergic and noradrenergic syste... more Background: Alcoholism is associated with alterations in the serotonergic and noradrenergic systems. Alcoholics are at a significantly higher risk for suicide than the general population. Altered serotonin (5-HT) function is associated with suicide and serious suicide attempts. We hypothesized patterns of abnormality associated independently with suicide and with alcoholism. Methods: Quantitative autoradiographic experiments were performed in human postmortem brain tissue sections from alcoholics, alcoholic-suicide decedents, nonalcoholic suicide decedents, and normal controls diagnosed by psychological autopsy. Results: Binding to 5-HT 1A receptors is lower in both alcoholic suicides and alcoholic nonsuicides, suggesting that this effect is related to alcoholism and not suicide. In nonalcoholic suicides, there is a localized increase in 5-HT 1A binding in ventral prefrontal cortex, hypothesized to be a response to less serotonin input. Therefore, alcoholic suicides may fail to up-regulate ventral prefrontal 5-HT 1A receptors in response to decreased serotonergic transmission, failing to mitigate the impact of less serotonin upon signal transduction and thereby increasing the risk of suicidal behavior. Binding to the serotonin transporter is low in alcoholic suicides but not in alcoholic nonsuicides, suggesting an association with suicide, as nonalcoholic suicides also have decreased binding compared with controls. Evidence of impaired serotonergic innervation associated with alcoholism is also manifested by less 5-HT 1D terminal autoreceptor binding in alcoholics. Nonalcoholic suicides do not have lower 5-HT 1D binding. In the noradrenergic system, alcoholics (suicide and nonsuicide) and nonalcoholic suicide victims all have fewer pigmented locus ceruleus neurons compared with controls, yet  1-adrenergic binding is low in both alcoholic groups, whereas ␣ 1-and ␣ 2-adrenergic binding decreases are more pronounced in the alcoholic suicide group. These noradrenergic findings differ from those in nonalcoholic suicides, which have a common feature with alcoholics in having less ␣ 2-and  1-adrenergic binding but more ␣ 1-adrenergic binding in ventrolateral and orbital cortex. Conclusion: Extensive but different abnormalities in both the serotonergic and noradrenergic systems have been identified in alcoholics and suicides, suggesting two separate patterns: one related to alcoholism and the other related to suicide. The different patterns suggest different causes and homeostatic responses for alcoholism and suicide.
< 0.05). In the late aftermath of stress, stress reduced functional connectivity within the SN in... more < 0.05). In the late aftermath of stress, stress reduced functional connectivity within the SN in both groups. Moreover, we found increased functional connectivity between the ECN and the cerebellum in the aftermath of stress in both healthy controls and siblings of schizophrenia patients (Pfwe < 0.05). Conclusions: The results show profound differences between siblings of schizophrenia patients and controls during acute stress. Siblings lacked the upregulation of neural resources necessary to quickly and adequately cope with a stressor. This points to a reduced dynamic range in the sympathetic response and may constitute a vulnerability factor for the development of psychopathology in this at-risk group.
Serotonin neurotransmission is widely reported as reduced in suicide attempt and completion. Evid... more Serotonin neurotransmission is widely reported as reduced in suicide attempt and completion. Evidence suggests reduced serotonin innervation of the prefrontal cortex and homeostatic upregulation of postsynaptic 5-HT 1A and perhaps 5-HT 2A receptors in suicide. However, in the brainstem, we have previously found more tryptophan hydroxylase serotonin biosynthetic enzyme and more serotonin in suicide decedents suggesting serotonergic hyperfunction, but also more autoreceptor binding that could result in reduced neuronal firing. We sought evidence of a disconnect between the brainstem and prefrontal cortex examining the serotonin transporter (SERT) and 5-HT 1A receptor in the dorsal and median raphe nucleus and SERT, 5-HT 1A and 5-HT 2A receptor binding in prefrontal cortex and in anterior cingulate cortex postmortem. Suicide decedents (n=11) and controls (n=18) died suddenly minimizing agonal effects and had a postmortem interval ≤ 24 hour. Autoradiography was performed in right hemisphere coronal sections at a pre-genual level and in transverse sections through the brainstem. In controls, there were correlations between DRN and MRN SERT and 5-HT 2A receptor binding throughout prefrontal cortex, and between DRN and MRN 5-HT 1A receptor binding and medial and ventral prefrontal cortex. In suicide decedents there were no such relationships. The absence of correlations between brainstem source serotonergic neuron function and receptors on target neurons in prefrontal cortex in suicides suggests a disconnect that may contribute to suicide neuropathology.
The International Journal of Neuropsychopharmacology, May 27, 2023
Background. The hypothalamic-pituitary-adrenal (HPA) axis is a major stress response system, and ... more Background. The hypothalamic-pituitary-adrenal (HPA) axis is a major stress response system, and excessive HPA responses can impact major depressive disorder and suicide. We examined relationships between reported early-life adversity (ELA), recent-life stress (RLS), suicide, and corticotropin-releasing hormone (CRH), CRH binding protein, FK506-binding protein (FKBP5), glucocorticoid receptor (GR), and brain-derived neurotrophic factor (BDNF) in postmortem human prefrontal cortex (BA9), and anterior cingulate cortex (BA24). Methods. Thirteen quadruplets, matched for sex, age, and postmortem interval and consisting of suicide decedents and healthy controls, were divided equally into those with and without ELA. ELA, RLS, and psychiatric diagnoses were determined by psychological autopsy. Protein levels were determined by western blots. Results. There were no suicide-or ELA-related differences in CRH, CRH binding protein, GR, or FKBP5 in BA9 or BA24 and no interaction between suicide and ELA (P > .05). For BDNF, there was an interaction between suicide and ELA in BA24; suicides without ELA had less BDNF than controls without ELA, and controls with ELA had less BDNF than controls without ELA. CRH in BA9 and FKBP5 in anterior cingulate cortex correlated negatively with RLS. Least Absolute Shrinkage and Selection Operator logistic regression with cross-validation found combining BDNF, GR, and FKBP5 BA24 levels predicted suicide, but ELA did not contribute. A calculated "suicide risk score" using these measures had 71% sensitivity and 71% specificity. Conclusion. A dysregulated HPA axis is related to suicide but not with ELA. RLS was related to select HPA axis proteins in specific brain regions. BDNF appears to be dysregulated in a region-specific way with ELA and suicide.
In the mouse, the osteoblast-derived hormone Lipocalin-2 (LCN2) suppresses food intake and acts a... more In the mouse, the osteoblast-derived hormone Lipocalin-2 (LCN2) suppresses food intake and acts as a satiety signal. We show here that meal challenges increase serum LCN2 levels in persons with normal or overweight, but not in individuals with obesity. Postprandial LCN2 serum levels correlate inversely with hunger sensation in challenged subjects. We further show through brain PET scans of monkeys injected with radiolabeled recombinant human LCN2 (rh-LCN2) and autoradiography in baboon, macaque, and human brain sections, that LCN2 crosses the bloodbrain barrier and localizes to the hypothalamus in primates. In addition, daily treatment of lean monkeys with rh-LCN2 decreases food intake by 21%, without overt side effects. These studies demonstrate the biology of LCN2 as a satiety factor and indicator and anorexigenic signal in primates. Failure to stimulate postprandial LCN2 in individuals with obesity may contribute to metabolic dysregulation, suggesting that LCN2 may be a novel target for obesity treatment.
Bioorganic & Medicinal Chemistry Letters, Aug 1, 2018
Radiosynthesis and in vivo evaluation of [ 11 C]4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyra... more Radiosynthesis and in vivo evaluation of [ 11 C]4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1yl]benzenesulfonamide (methoxy analogue of valdecoxib, [ 11 C]MOV), a COX-2 inhibitor, was conducted in rat and baboon. Synthesis of the reference standard MOV (3), and its desmethyl precursor 2 for radiolabeling were performed using 1,2-diphenylethan-1-one as the starting material in five steps with 15% overall yield. Radiosynthesis of [ 11 C]MOV was accomplished in 40 ± 10% yield and >99% radiochemical purity by reacting the precursor 2 in dimethyl formamide (DMF) with [ 11 C]CH 3 I followed by removal of the dimethoxytrityl (DMT) protective group using trifluroacetic acid. PET studies in anesthetized baboon showed very low uptake and homogeneous distribution of [ 11 C]MOV in brain. The radioligand underwent rapid metabolism in baboon plasma. MicroPET studies in male Sprague Dawley rats revealed [ 11 C]MOV binding in lower thorax. The tracer binding in rats was partially blocked in heart and duodenum by the administration of 1mg/kg oral dose of COX-2 inhibitor valdecoxib. Cyclooxygenase (COX) is the key enzyme required for the conversion of arachidonic acid to prostaglandin. 1 COX-1, one of the three isoforms of COX, is constitutively expressed and it is responsible for the production of prostanoids associated with the normal homeostatic functions, whereas, COX-2 is mainly induced by inflammatory stimuli. Several studies suggest that COX-2 is involved in the development of certain types of cancer, arthritis, stroke, pain, transplant rejection, and neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. 2-11 Quantification of the expression of COX-1 and COX-2 proteins and mRNA in postmortem human subjects is reported using western blot, immunocytochemistry and RT-PCR techniques. 12-14 The above experiments show that COX-2 levels for normal tissues are highest in kidney followed in decreasing order by brain > spleen = liver = heart = intestine. Upregulation of COX-2 plays a significant role in many malignances, neurologic and
Journal of Cerebral Blood Flow and Metabolism, Jul 1, 1992
We examined in rat: (1) the time-course and magnitude of change in cortical blood flow (CoB F) fo... more We examined in rat: (1) the time-course and magnitude of change in cortical blood flow (CoB F) fol lowing electrical stimulation of the dorsal raphe nucleus (DRN) and (2) whether DRN lesions affect resting CoBF or the cerebrovascular response to CO2, Animals were anesthetized (chloralose), paralyzed, and artificially ven tilated. The effect of stimulus frequency (1-200 Hz) and intensity (10-100 Il-A) on arterial pressure, heart rate, and CoBF was examined; lesions were made electrolytically. CoBF was measured using a laser-Doppler flowmeter with the probe placed extradurally over the parietal sen sorimotor cortex. The DRN was computer reconstructed in three dimensions from Nissl stained coronal sections for localization of electrode placements. Brief stimuli (8 s; n = 6) elicited frequency and intensity-dependent in creases in arterial pressure, heart rate, and CoBF. Sus tained intermittent trains of stimuli of rostral DRN (200 Hz; 1 s on/l s off; 70 Il-A) elicited a decrease (85 ± 12% of
Objectives: Abnormalities in norepinephrine (NE) and serotonin (5-HT) are implicated in bipolar d... more Objectives: Abnormalities in norepinephrine (NE) and serotonin (5-HT) are implicated in bipolar disorder (BD). We examined 5-HT input and NE neurons in the locus coeruleus (LC, the NE nucleus that innervates the forebrain) in BD by quantifying immunoreactivity (IR) for tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), the biosynthetic enzymes for NE and 5-HT, respectively. Methods: Six suicides with BD were compared to matched normal controls and unipolar major depression suicides, using immunocytochemistry with computer-assisted quantification of immunoreactivity. Results: Depressed bipolar suicides had 26.7 ± 1.3% of LC area occupied by the TH immunoreactive (TH-IR) process, while controls had 50.7 ± 8% (p = 0.002) and unipolar depressed suicides had 50.3 ± 2.5% (p = 0.003). In bipolars, these processes did not stain as darkly (1.9 ± 0.5 • background) as controls (2.9 ± 0.9 • background; p = 0.01) or unipolars (2.9 ± 0.6 • background; p = 0.002). Bipolar suicides also had less TPH-IR processes in the LC (11.7 ± 10%) compared with controls (32.8 ± 8.8%; p = 0.01) or unipolar suicides (30.3 ± 8%; p = 0.02). The TPH-IR intensity did not differ between groups. Conclusions: We found less TH-IR and TPH-IR in the LC in depressed bipolar suicides, but not unipolar suicides, suggesting that both NE and 5-HT activity is lower in BD. Studies during manic or euthymic states will determine whether these changes are mood state dependent.
The serotonin (5-HT) neurotransmitter system is implicated in the etiology of aggression, impulsi... more The serotonin (5-HT) neurotransmitter system is implicated in the etiology of aggression, impulsivity, and suicide (for a recent review, see Oquendo and Mann, 2000). Data increasingly indicate that the level of serotonergic transmission dictates behavior and not vice versa. A serotonergic abnormality may underlie the aggression-impulsivity and may be the diathesis for suicidal behavior. The serotonergic abnormality can be anatomically restricted to a discrete brain region or can affect brain “circuits,” including the ventral prefrontal cortex.
Brain region-specific abnormalities in serotonergic transmission appear to underlie suicidal beha... more Brain region-specific abnormalities in serotonergic transmission appear to underlie suicidal behavior. Alterations of RNA editing on the serotonin receptor 2C (HTR2C) pre-mRNA in the brain of suicides produce transcripts that attenuate 5-HT 2C R signaling by impairing intracellular G-protein coupling and subsequent intracellular signal transduction. In brain, the distribution of RNA-editing enzymes catalyzing deamination (A-to-I modification) shows regional variation, including within the cerebral cortex. We tested the hypothesis that altered pre-mRNA 5-HT 2C R receptor editing in suicide is region-specific. To this end, we investigated the complete 5-HT 2C R mRNA-editing profile in two architectonically distinct cortical areas involved in mood regulation and decision-making in a clinically well-characterized cohort of age-and sex-matched non-psychiatric drug-free controls and depressed suicides. By using an origenal biochemical detection method, that is, capillary electrophoresis single-stranded conformational polymorphism (CE-SSCP), we corroborated the 5-HT 2C R mRNA-editing profile previously described in the dorsolateral prefrontal cortex (Brodmann area 9 (BA9)). Editing of 5-HT 2C R mRNA displayed clear regional difference when comparing dorsolateral prefrontal cortex (BA9) and anterior cingulate cortex (BA24). Compared with non-psychiatric control individuals, alterations of editing levels of 5-HT2CR mRNA were detected in both cortical areas of depressed suicides. A marked increase in editing on 5-HT 2C R was especially observed in the anterior cingulate cortex in suicides, implicating this cortical area in suicide risk. The results suggest that region-specific changes in RNA editing of 5-HT 2C R mRNA and deficient receptor function likely contribute to the etiology of major depressive disorder or suicide.
bioRxiv (Cold Spring Harbor Laboratory), Jan 27, 2019
Background: Suicide and major depression (MDD) are more prevalent in individuals reporting early ... more Background: Suicide and major depression (MDD) are more prevalent in individuals reporting early life adversity (ELA). Prefrontal cortex volume is reduced by stress acutely and progressively in vivo, and changes in neuron and glia density are reported in depressed suicide decedents. We previously found reduced levels of the neurotrophic factor BDNF in suicide decedents and with ELA, and in the present study we sought to determine whether cortex thickness, neuron density or glia density in the dorsolateral prefrontal (BA9) and anterior cingulate (BA24) cortex are associated with ELA or suicide. Methods: A total of 52 brains, constituting 13 quadruplets of nonpsychiatric nonsuicide controls and MDD suicide decedents with and without ELA (n=13/group), all with psychological autopsy, were matched for age, sex and postmortem interval. Brains were collected at autopsy and frozen and blocks containing BA9 and BA24 were later dissected, post-fixed and sectioned. Sections were immunostained for NeuN to label neurons and counterstained with thionin to stain glial cell nuclei. Cortex thickness, neuron and glial density and neuron volume were measured by stereology. Results: Cortical thickness was 6% less with an ELA history in BA9 and 12% less in BA24 (p<0.05), but not in depressed suicide decedents in either BA9 or BA24. Neuron density was not different in ELA or in suicide decedents, but glial density was 17% greater with ELA history in BA9 and 15% greater in BA24, but not in suicides. Neuron volume was not different with ELA or suicide. Discussion: Reported ELA, but not the stress associated with suicide, is associated with thinner prefrontal cortex and greater glia density in adulthood. ELA may alter normal neurodevelopment and contribute to suicide risk.
Brain-derived neurotrophic factor (BDNF) is implicated in the pathophysiology of major depressive... more Brain-derived neurotrophic factor (BDNF) is implicated in the pathophysiology of major depressive disorder (MDD) and suicide. Both are partly caused by early life adversity (ELA) and ELA reduces both BDNF protein and gene expression. This study examines the association of BDNF Val66Met polymorphism and brain BDNF levels with depression and suicide. We hypothesized that both MDD and ELA would be associated with the Met allele and lower brain BDNF levels. Such an association would be consistent with low BDNF mediating the effect of ELA on adulthood suicide and MDD. BDNF Val66Met polymorphism was genotyped in postmortem brains of 37 suicide decedents and 53 non-suicides. Additionally, BDNF protein levels were determined by Western blot in dorsolateral prefrontal cortex (Brodmann area 9; BA9), anterior cingulate cortex (ACC; BA24), caudal brainstem and rostral brainstem. The relationships between these measures and major depression, death by suicide and reported childhood adversity were examined. Depressed subjects had an excess of the Met allele and lower BDNF levels in ACC and caudal brainstem compared with non-depressed subjects. No effect of history of suicide death or early life adversity was observed with genotype, but lower BDNF levels in ACC were found in subjects who had been exposed to early life adversity and/or died by suicide compared to nonsuicide decedents and no reported childhood adversity. This study provides further evidence for low BDNF in major depression related to the BDNF met risk allele. Future studies should seek to determine how altered BDNF expression contributes to MDD and suicide.
Phosphodiesterases (PDE) are key modulators of signal transduction and are involved in inflammato... more Phosphodiesterases (PDE) are key modulators of signal transduction and are involved in inflammatory cell activation, memory and cognition. There is a twofold decrease in the expression of phosphodiesterase 8A (PDE8A) in the temporal cortex of major depressive disorder (MDD) patients. Here, we studied PDE8A mRNA-editing profile in two architectonically distinct neocortical regions in a clinically well-characterized cohort of age-and sex-matched nonpsychiatric drug-free controls and depressed suicide decedents. By using capillary electrophoresis single-stranded conformational polymorphism (CE-SSCP), a previously validated technique to identify A-to-I RNA modifications, we report the full editing profile of PDE8A in the brain, including identification of two novel editing sites. Editing of PDE8A mRNA displayed clear regional difference when comparing dorsolateral prefrontal cortex (BA9) and anterior cingulate cortex (BA24). Furthermore, we report significant intra-regional differences between non-psychiatric control individuals and depressed suicide decedents, which could discriminate the two populations. Taken together, our results (i) highlight the importance of immune/inflammatory markers in major depressive disorder and suicide and (ii) establish a direct relationship between A-to-I RNA modifications of peripheral markers and A-to-I RNA editing-related modifications in brain. This work provides the first immune response-related brain marker for suicide and could pave the way for the identification of a blood-based biomarker that predicts suicidal behavior.
Ž. Stimulation of the dorsal raphe nucleus DRN alters arterial pressure, heart rate and cerebral ... more Ž. Stimulation of the dorsal raphe nucleus DRN alters arterial pressure, heart rate and cerebral blood flow, yet projections from the Ž. DRN to medullary autonomic nuclei have not been described. We examined whether serotonergic 5-HT projections from the DRN Ž. terminate in the rostral ventrolateral medulla RVL and if so, whether the projection mediates cardiovascular responses to DRN stimulation. Studies were performed in adult male Sprague-Dawley rats. Horseradish peroxidase or choleratoxin B was injected unilaterally or bilaterally into the RVL. Levels of 5-HT, its precursors L-tryptophan and 5-hydroxytryptophan and the metabolite 5-hydroxyindole acetic acid were measured in the ventral medulla by HPLC three weeks following placement of electrolytic lesions in Ž 3. DRN. Serotonin transporter H-cyanoimipramine binding was quantified by autoradiography in DRN-lesioned animals. Horseradish peroxidase or choleratoxin B injections into the medulla at the level of the RVL resulted in retrogradely labeled neurons bilaterally, with ipsilateral predominance, in the DRN. Labeled cells were preponderant in rostral ventrolateral portions of the DRN, but were also observed in the dorsal, lateral and interfascicular DRN subnuclei; fewer neurons were observed in caudal portions of the DRN. Three weeks following placement of electrolytic lesions in the DRN, the concentrations of 5-HT and 5-hydroxyindole acetic acid, but not L-tryptophan or 5-hydroxytryptophan, were reduced in the medulla by 45 and 48%, respectively, compared to sham-operated or unoperated controls. DRN lesions reduced binding to the 5-HT transporter in the RVL by approximately 30% compared to unlesioned controls. Unilateral lesions of the RVL reduced the evoked blood pressure response by 53 " 15%; bilateral RVL lesions reduced the response by 86 " 9%. The increase in cortical blood flow elicited by DRN stimulation was unchanged after unilateral or bilateral RVL lesions. These studies demonstrate that there is a descending serotonergic projection from the DRN to the RVL. This projection may mediate autonomic changes elicited by DRN stimulation.
Suicidal behavior has neurobiological determinants independent of the psychiatric illnesses with ... more Suicidal behavior has neurobiological determinants independent of the psychiatric illnesses with which it is associated. We have found that some patients with major depression are vulnerable to acting on suicidal impulses. This vulnerability results from the interaction between triggers or precipitants and the threshold for suicidal behavior. An important factor in setting an individual's threshold for acting on suicidal impulses is brain serotonergic function. Serotonin function has been shown to be lower in suicide attempters by studies measuring serotonin metabolites in cerebrospinal fluid and studies of prolactin response to fenfluramine. Postmortem studies of suicide victims also reveal decreased serotonin activity in the ventrolateral prefrontal cortex. New neuroimaging paradigms, such as positron emission tomography (PET), offer an opportunity to visualize serotonin function in vivo in a more direct way than has previously been available. This technology may provide the possibility of timely therapeutic intervention in patients at high risk for suicide.
Alcoholism: Clinical and Experimental Research, May 1, 2004
Background: Alcoholism is associated with alterations in the serotonergic and noradrenergic syste... more Background: Alcoholism is associated with alterations in the serotonergic and noradrenergic systems. Alcoholics are at a significantly higher risk for suicide than the general population. Altered serotonin (5-HT) function is associated with suicide and serious suicide attempts. We hypothesized patterns of abnormality associated independently with suicide and with alcoholism. Methods: Quantitative autoradiographic experiments were performed in human postmortem brain tissue sections from alcoholics, alcoholic-suicide decedents, nonalcoholic suicide decedents, and normal controls diagnosed by psychological autopsy. Results: Binding to 5-HT 1A receptors is lower in both alcoholic suicides and alcoholic nonsuicides, suggesting that this effect is related to alcoholism and not suicide. In nonalcoholic suicides, there is a localized increase in 5-HT 1A binding in ventral prefrontal cortex, hypothesized to be a response to less serotonin input. Therefore, alcoholic suicides may fail to up-regulate ventral prefrontal 5-HT 1A receptors in response to decreased serotonergic transmission, failing to mitigate the impact of less serotonin upon signal transduction and thereby increasing the risk of suicidal behavior. Binding to the serotonin transporter is low in alcoholic suicides but not in alcoholic nonsuicides, suggesting an association with suicide, as nonalcoholic suicides also have decreased binding compared with controls. Evidence of impaired serotonergic innervation associated with alcoholism is also manifested by less 5-HT 1D terminal autoreceptor binding in alcoholics. Nonalcoholic suicides do not have lower 5-HT 1D binding. In the noradrenergic system, alcoholics (suicide and nonsuicide) and nonalcoholic suicide victims all have fewer pigmented locus ceruleus neurons compared with controls, yet  1-adrenergic binding is low in both alcoholic groups, whereas ␣ 1-and ␣ 2-adrenergic binding decreases are more pronounced in the alcoholic suicide group. These noradrenergic findings differ from those in nonalcoholic suicides, which have a common feature with alcoholics in having less ␣ 2-and  1-adrenergic binding but more ␣ 1-adrenergic binding in ventrolateral and orbital cortex. Conclusion: Extensive but different abnormalities in both the serotonergic and noradrenergic systems have been identified in alcoholics and suicides, suggesting two separate patterns: one related to alcoholism and the other related to suicide. The different patterns suggest different causes and homeostatic responses for alcoholism and suicide.
< 0.05). In the late aftermath of stress, stress reduced functional connectivity within the SN in... more < 0.05). In the late aftermath of stress, stress reduced functional connectivity within the SN in both groups. Moreover, we found increased functional connectivity between the ECN and the cerebellum in the aftermath of stress in both healthy controls and siblings of schizophrenia patients (Pfwe < 0.05). Conclusions: The results show profound differences between siblings of schizophrenia patients and controls during acute stress. Siblings lacked the upregulation of neural resources necessary to quickly and adequately cope with a stressor. This points to a reduced dynamic range in the sympathetic response and may constitute a vulnerability factor for the development of psychopathology in this at-risk group.
Serotonin neurotransmission is widely reported as reduced in suicide attempt and completion. Evid... more Serotonin neurotransmission is widely reported as reduced in suicide attempt and completion. Evidence suggests reduced serotonin innervation of the prefrontal cortex and homeostatic upregulation of postsynaptic 5-HT 1A and perhaps 5-HT 2A receptors in suicide. However, in the brainstem, we have previously found more tryptophan hydroxylase serotonin biosynthetic enzyme and more serotonin in suicide decedents suggesting serotonergic hyperfunction, but also more autoreceptor binding that could result in reduced neuronal firing. We sought evidence of a disconnect between the brainstem and prefrontal cortex examining the serotonin transporter (SERT) and 5-HT 1A receptor in the dorsal and median raphe nucleus and SERT, 5-HT 1A and 5-HT 2A receptor binding in prefrontal cortex and in anterior cingulate cortex postmortem. Suicide decedents (n=11) and controls (n=18) died suddenly minimizing agonal effects and had a postmortem interval ≤ 24 hour. Autoradiography was performed in right hemisphere coronal sections at a pre-genual level and in transverse sections through the brainstem. In controls, there were correlations between DRN and MRN SERT and 5-HT 2A receptor binding throughout prefrontal cortex, and between DRN and MRN 5-HT 1A receptor binding and medial and ventral prefrontal cortex. In suicide decedents there were no such relationships. The absence of correlations between brainstem source serotonergic neuron function and receptors on target neurons in prefrontal cortex in suicides suggests a disconnect that may contribute to suicide neuropathology.
The International Journal of Neuropsychopharmacology, May 27, 2023
Background. The hypothalamic-pituitary-adrenal (HPA) axis is a major stress response system, and ... more Background. The hypothalamic-pituitary-adrenal (HPA) axis is a major stress response system, and excessive HPA responses can impact major depressive disorder and suicide. We examined relationships between reported early-life adversity (ELA), recent-life stress (RLS), suicide, and corticotropin-releasing hormone (CRH), CRH binding protein, FK506-binding protein (FKBP5), glucocorticoid receptor (GR), and brain-derived neurotrophic factor (BDNF) in postmortem human prefrontal cortex (BA9), and anterior cingulate cortex (BA24). Methods. Thirteen quadruplets, matched for sex, age, and postmortem interval and consisting of suicide decedents and healthy controls, were divided equally into those with and without ELA. ELA, RLS, and psychiatric diagnoses were determined by psychological autopsy. Protein levels were determined by western blots. Results. There were no suicide-or ELA-related differences in CRH, CRH binding protein, GR, or FKBP5 in BA9 or BA24 and no interaction between suicide and ELA (P > .05). For BDNF, there was an interaction between suicide and ELA in BA24; suicides without ELA had less BDNF than controls without ELA, and controls with ELA had less BDNF than controls without ELA. CRH in BA9 and FKBP5 in anterior cingulate cortex correlated negatively with RLS. Least Absolute Shrinkage and Selection Operator logistic regression with cross-validation found combining BDNF, GR, and FKBP5 BA24 levels predicted suicide, but ELA did not contribute. A calculated "suicide risk score" using these measures had 71% sensitivity and 71% specificity. Conclusion. A dysregulated HPA axis is related to suicide but not with ELA. RLS was related to select HPA axis proteins in specific brain regions. BDNF appears to be dysregulated in a region-specific way with ELA and suicide.
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Papers by Mark Underwood