Integrative transcriptome- and DNA methylation analysis of brain tissue from the temporal pole in suicide decedents and their controls.

Suicide rates have increased steadily world-wide over the past two decades, constituting a serious public health crisis that creates a significant burden to affected families and the society as a whole. Suicidal behavior involves a multi-factorial etiology, including psychological, social and biological factors. Since the molecular neural mechanisms of suicide remain vastly uncharacterized, we examined transcriptional- and methylation profiles of postmortem brain tissue from subjects who died from suicide as well as their neurotypical healthy controls. We analyzed temporal pole tissue from 61 subjects, largely free from antidepressant and antipsychotic medication, using RNA-sequencing and DNA-methylation profiling using an array that targets over 850,000 CpG sites. Expression of NPAS4, a key regulator of inflammation and neuroprotection, was significantly downregulated in the suicide decedent group. Moreover, we identified a total of 40 differentially methylated regions in the suicide decedent group, mapping to seven genes with inflammatory function. There was a significant association between NPAS4 DNA methylation and NPAS4 expression in the control group that was absent in the suicide decedent group, confirming its dysregulation. NPAS4 expression was significantly associated with the expression of multiple inflammatory factors in the brain tissue. Overall, gene sets and pathways closely linked to inflammation were significantly upregulated, while specific pathways linked to neuronal development were suppressed in the suicide decedent group. Excitotoxicity as well as suppressed oligodendrocyte function were also implicated in the suicide decedents. In summary, we have identified central nervous system inflammatory mechanisms that may be active during suicidal behavior, along with oligodendrocyte dysfunction and altered glutamate neurotransmission. In these processes, NPAS4 might be a master regulator, warranting further studies to validate its role as a potential biomarker or therapeutic target in suicidality.

A Stress Protein-Based Suicide Prediction Score and Relationship to Reported Early-Life Adversity and Recent Life Stress.

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.

Lipocalin-2 is an anorexigenic signal in primates.

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 blood-brain 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.

Obesity has reached epidemic proportions worldwide and affects more than 40% of adults in the United States. People with obesity have a greater likelihood of developing type 2 diabetes, cardiovascular disease or chronic kidney disease. Changes in diet and exercise can be difficult to follow and result in minimal weight loss that is rarely sustained overtime. In fact, in people with obesity, weight loss can lower the metabolism leading to increased weight gain. New drugs may help some individuals achieve 5 to 10% weight loss but have side effects that prevent long-term use. Previous studies in mice show that a hormone called Lipocalin-2 (LCN2) suppresses appetite. It also reduces body weight and improves sugar metabolism in the animals. But whether this hormone has the same effects in humans or other primates is unclear. If it does, LCN2 might be a potential obesity treatment. Now, Petropoulou et al. show that LCN2 suppressed appetite in humans and monkeys. In human studies, LCN2 levels increased after a meal in individuals with normal weight or overweight, but not in individuals with obesity. Higher levels of LCN2 in a person's blood were also associated with a feeling of reduced hunger. Using brain scans, Petropoulou et al. showed that LCN2 crossed the blood-brain barrier in monkeys and bound to the hypothalamus, the brain center regulating appetite and energy balance. LCN2 also bound to human and monkey hypothalamus tissue in laboratory experiments. When injected into monkeys, the hormone suppressed food intake and lowered body weight without toxic effects in short-term studies. The experiments lay the initial groundwork for testing whether LCN2 might be a useful treatment for obesity. More studies in animals will help scientists understand how LCN2 works, which patients might benefit, how it would be given to patients and for how long. Clinical trials would also be needed to verify whether it is an effective and safe treatment for obesity.

Less NMDA Receptor Binding in Dorsolateral Prefrontal Cortex and Anterior Cingulate Cortex Associated With Reported Early-Life Adversity but Not Suicide.

BACKGROUND: Glutamate is an excitatory neurotransmitter binding to 3 classes of receptors, including the N-methyl, D-aspartate (NMDA) receptor. NMDA receptor binding is lower in major depression disorder and suicide. NMDA receptor blocking with ketamine can have antidepressant and anti-suicide effects. Early-life adversity (ELA) may cause glutamate-mediated excitotoxicity and is more common with major depression disorder and in suicide decedents. We sought to determine whether NMDA-receptor binding is altered with suicide and ELA. METHODS: A total 52 postmortem cases were organized as 13 quadruplets of suicide and non-suicide decedents matched for age, sex, and postmortem interval, with or without reported ELA (≤16 years). Tissue blocks containing dorsal prefrontal (BA8), dorsolateral prefrontal (BA9), or anterior cingulate (BA24) cortex were collected at autopsy. Psychiatrically healthy controls and suicide decedents underwent psychological autopsy to determine psychiatric diagnoses and details of childhood adversity. NMDA receptor binding was determined by quantitative autoradiography of [3H]MK-801 binding (displaced by unlabeled MK-801) in 20-µm-thick sections. RESULTS: [3H]MK-801 binding was not associated with suicide in BA8, BA9, or BA24. However, [3H]MK-801 binding with ELA was less in BA8, BA9, and BA24 independent of suicide (P < .05). [3H]MK-801 binding was not associated with age or postmortem interval in any brain region or group. CONCLUSIONS: Less NMDA receptor binding with ELA is consistent with the hypothesis that stress can cause excitotoxicity via excessive glutamate, causing either NMDA receptor downregulation or less receptor binding due to neuron loss consequent to the excitotoxicity.

GAD mRNA in Orbital Prefrontal Cortex and Anterior Cingulate Cortex in Alcoholics Compared with Nonpsychiatric Controls: A Negative Postmortem Study.

Alcohol increases inhibitory neurotransmission, an effect mediated through GABA receptors. With chronic alcohol exposure, the inhibitory effects diminish. Glutamic acid decarboxylase (GAD) catalyzes glutamate in the synthesis of GABA. We sought to determine the amount of GAD65/67 mRNA in anterior cingulate cortex (BA24) and orbital prefrontal cortex (BA45) of medication-free alcoholics and nonpsychiatric controls postmortem. Studies were performed in 16 pairs of nonpsychiatric controls and alcoholics, matched for age, sex and PMI. DSM-IV diagnosis of alcohol use disorder (AUD) was made by the SCID I in a psychological autopsy. Frozen blocks of BA24 or BA45 were sectioned (10 µm) for in situ hybridization of 35S-labelled riboprobe for GAD65/67 mRNA and autoradiograms were analyzed by quantitative densitometry. Three isodensity bands of labeling were evident, with different relative amounts of GAD65 and GAD67 (outer and inner, predominantly GAD65, intermediate predominantly GAD67), and the isodensity bands were analyzed separately. GAD65/67 mRNA levels were not different between alcoholics and controls in the gray matter of BA24 (p = 0.53) or BA45 (p = 0.84) or in any of the three isodensity bands in which the GAD65/67 mRNA was distributed. GAD65/67 mRNA in white matter underlying either region was also not different in alcoholics (p > 0.05). GAD65/67 mRNA levels did not correlate with age, sex or duration of alcoholism in either BA24 or BA45. Effects on inhibitory neurotransmission in alcoholics do not appear to be associated with change in the levels of GAD65 or GAD67 mRNA.

5-HT1A receptor, 5-HT2A receptor and serotonin transporter binding in the human auditory cortex in depression

Background: Serotonergic system abnormalities are implicated in many psychiatric disorders, including major depression. The temporal lobe receives a high density of serotonergic afferent projections, and responses in the primary auditory cortex to sound are modulated by serotonergic tone. However, the associations between changes in serotonergic tone, disease state and changes in auditory cortical function remain to be clarified. Methods: We quantified serotonin 1A (5-HT1A) receptor binding, serotonin 2A (5-HT2A) receptor binding, and serotonin transporter (SERT) binding in Brodmann areas (BA) 41/42, 22, 9 and 4 from postmortem brain sections of 40 psychiatrically healthy controls and 39 individuals who had a history of a major depressive episode (MDE). Results: There was 33% lower 5-HT2A receptor binding in BA 41/42 in individuals who had an MDE than in controls (p = 0.0069). Neither 5-HT1A nor SERT binding in BA 41/42 differed between individuals who had an MDE and controls. We also found 14% higher 5-HT1A receptor binding (p = 0.045) and 21% lower SERT binding in BA 9 of individuals who had an MDE (p = 0.045). Limitations: The study was limited by the small number of postmortem brain samples including BA 41/42 available for binding assays and the large overlap between suicide and depression in the MDE sample. Conclusion: Depression may be associated with altered serotonergic function in the auditory cortex involving the 5-HT2A receptor and is part of a wider view of the pathophysiology of mood disorders extending beyond psychopathology.

Correction: Brain region-specific alterations of RNA editing in PDE8A mRNA in suicide decedents.

Author forgot to attach a supplementary doc file which includes the supplementary methods and supplementary figure legends.

Early-Life Adversity, but Not Suicide, Is Associated With Less Prefrontal Cortex Gray Matter in Adulthood.

BACKGROUND: Suicide and major depression are prevalent in individuals reporting early-life adversity. Prefrontal cortex volume is reduced by stress acutely and progressively, and changes in neuron and glia density are reported in depressed suicide decedents. We previously found reduced neurotrophic factor brain-derived neurotrophic factor in suicide decedents and with early-life adversity, and we sought to determine whether cortex thickness or neuron or glia density in the dorsolateral prefrontal and anterior cingulate cortex are associated with early-life adversity or suicide. METHODS: A total of 52 brains, constituting 13 quadruplets of nonpsychiatric controls and major depressive disorder suicide decedents with and without early-life adversity, were matched for age, sex, race, and postmortem interval. Brains were collected at autopsy and frozen, and dorsolateral prefrontal cortex and anterior cingulate cortex were later dissected, postfixed, and sectioned. Sections were immunostained for neuron-specific nuclear protein (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 early-life adversity in dorsolateral prefrontal cortex and 12% less in anterior cingulate cortex (P < .05), but not in depressed suicide decedents in either region. Neuron density was not different in early-life adversity or with suicide, but glial density was 17% greater with early-life adversity in dorsolateral prefrontal cortex and 15% greater in anterior cingulate cortex, but not in suicides. Neuron volume was not different with early-life adversity or suicide. CONCLUSIONS: Reported early-life adversity, but not the stress associated with suicide, is associated with thinner prefrontal cortex and greater glia density in adulthood. Early-life adversity may alter normal neurodevelopment and contribute to suicide risk.

Brain region-specific alterations of RNA editing in PDE8A mRNA in suicide decedents.

Phosphodiesterases (PDE) are key modulators of signal transduction and are involved in inflammatory cell activation, memory and cognition. There is a two-fold 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 non-psychiatric 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.

Serotonin receptors and suicide, major depression, alcohol use disorder and reported early life adversity.

Serotonin neurotransmitter deficits are reported in suicide, major depressive disorder (MDD) and alcohol use disorder (AUD). To compare pathophysiology in these disorders, we mapped brain serotonin transporter (SERT), 5-HT1A, and 5-HT2A receptor binding throughout prefrontal cortex and in anterior cingulate cortex postmortem. Cases and controls died suddenly minimizing agonal effects and had a postmortem interval ≤24 h to avoid compromised brain integrity. Neuropathology and toxicology confirmed absence of neuropathology and psychotropic medications. For most subjects (167 of 232), a DSM-IV Axis I diagnosis was made by psychological autopsy. Autoradiography was performed in right hemisphere coronal sections at a pre-genual level. Linear model analyses included sex and age with group and Brodmann area as interaction terms. SERT binding was lower in suicides (p = 0.004) independent of sex (females < males, p < 0.0001), however, the lower SERT binding was dependent on MDD diagnosis (p = 0.014). Higher SERT binding was associated with diagnosis of alcoholism (p = 0.012). 5-HT1A binding was greater in suicides (p < 0.001), independent of MDD (p = 0.168). Alcoholism was associated with higher 5-HT1A binding (p < 0.001) but only in suicides (p < 0.001). 5-HT2A binding was greater in suicides (p < 0.001) only when including MDD (p = 0.117) and alcoholism (p = 0.148) in the model. Reported childhood adversity was associated with higher SERT and 5-HT1A binding (p = 0.004) in nonsuicides and higher 5-HT2A binding (p < 0.001). Low SERT and more 5-HT1A and 5-HT2A binding in the neocortex in depressed suicides is dependent on Axis I diagnosis and reported childhood adversity. Findings in alcoholism differed from those in depression and suicide indicating a distinct serotonin system pathophysiology.

Association of BDNF Val66Met Polymorphism and Brain BDNF Levels with Major Depression and Suicide.

Background: Brain-derived neurotrophic factor is implicated in the pathophysiology of major depressive disorder and suicide. Both are partly caused by early life adversity, which reduces brain-derived neurotrophic factor protein levels. This study examines the association of brain-derived neurotrophic factor Val66Met polymorphism and brain brain-derived neurotrophic factor levels with depression and suicide. We hypothesized that both major depressive disorder and early life adversity would be associated with the Met allele and lower brain brain-derived neurotrophic factor levels. Such an association would be consistent with low brain-derived neurotrophic factor mediating the effect of early life adversity on adulthood suicide and major depressive disorder. Methods: Brain-derived neurotrophic factor Val66Met polymorphism was genotyped in postmortem brains of 37 suicide decedents and 53 nonsuicides. Additionally, brain-derived neurotrophic factor protein levels were determined by Western blot in dorsolateral prefrontal cortex (Brodmann area 9), anterior cingulate cortex (Brodmann area 24), caudal brainstem, and rostral brainstem. The relationships between these measures and major depressive disorder, death by suicide, and reported early life adversity were examined. Results: Subjects with the Met allele had an increased risk for depression. Depressed patients also have lower brain-derived neurotrophic factor levels in anterior cingulate cortex and caudal brainstem compared with nondepressed subjects. No effect of history of suicide death or early life adversity was observed with genotype, but lower brain-derived neurotrophic factor levels in the anterior cingulate cortex were found in subjects who had been exposed to early life adversity and/or died by suicide compared with nonsuicide decedents and no reported early life adversity. Conclusions: This study provides further evidence implicating low brain brain-derived neurotrophic factor and the brain-derived neurotrophic factor Met allele in major depression risk. Future studies should seek to determine how altered brain-derived neurotrophic factor expression contributes to depression and suicide.

Dysregulation of Striatal Dopamine Receptor Binding in Suicide.

Inconsistent evidence implicates disruptions of striatal dopaminergic indices in suicide and major depression. To determine whether there are alterations in the striatal dopamine system in suicide, we conducted a quantitative autoradiographic survey of dopamine transporter (DAT; [3H]mazindol), D1 receptor ([3H]SCH23390), and D2 receptor ([3H]sulpiride) binding in the dorsal striatum postmortem from matched suicides and controls. Axis I and axis II psychiatric diagnosis, recent treatment history, and early life adversity (ELA) were determined by psychological autopsy. Mean DAT, D2, and D1 receptor binding did not differ in suicide. However, there was a positive correlation between D1 and D2 receptor binding in the dorsal striatum of control subjects (R2=0.31, p<0.05) that was not present in suicides (R2=0.00, p=0.97). In suicides and controls with reported ELA, there was no correlation between striatal DAT and D1 receptor binding (R2=0.07, p=0.33), although DAT and D1 receptor binding was positively correlated in subjects with no report of ELA (R2=0.32, p<0.05). After controlling for age, there were no significant ELA-related mean differences. Binding of D1 receptors and DAT throughout the striatum correlated negatively with age (D1 receptor: R2=0.12, p<0.05; DAT: R2=0.36, p<0.001). There appears to be an imbalance in dopaminergic receptor and transporter expression related to suicide that differs from that associated with ELA or age.

Autoradiographic Evaluation of [(18)F]FECUMI-101, a High Affinity 5-HT1AR Ligand in Human Brain.

[(18)F]FECUMI-101 ([(18)F]1) is a 5HT1AR ligand demonstrating specific binding in brain regions corresponding to the distribution of 5-HT1AR in baboons. However, we detected moderate uptake of [(18)F]1 in baboon thalamus, a brain region lacking 5-HT1AR. We sought to investigate the relative binding of [(18)F]1 to 5-HT1AR, α1R, and 5-HT7R in vitro. Using autoradiography in human brain sections, specific binding of [(18)F]1 to 5-HT1AR was confirmed. However, [(18)F]1 also showed 26% binding to α1R in PFC. The hippocampal formation exhibited 51% and 92% binding of [(18)F]1 to α1R and 5-HT1AR, respectively. Thalamus and cerebellum showed very little binding. There is no measurable specific binding of [(18)F]1 to 5-HT7R and no effect of temperature on [(18)F]1 specific binding to 5-HT1AR or α1R. These results indicate that, while [(18)F]FECUMI-101 is not a completely selective 5-HT1AR ligand for receptor quantification, it may be useful for occupancy measurements of drugs acting at 5-HT1AR in vivo.

Cigarette Smoking and Tryptophan Hydroxylase 2 mRNA in the Dorsal Raphe Nucleus in Suicides.

Cigarette smoking is associated with suicide and mood disorders and stimulates serotonin release. Tryptophan hydroxylase (TPH2) synthesizes serotonin and is over-expressed in suicides. We determined whether smoking is associated with TPH2 mRNA in suicides and controls. TPH2 mRNA was measured postmortem in the dorsal raphe nucleus (DRN) of controls (N = 26, 17 nonsmokers and nine smokers) and suicides (N = 23, 5 nonsmokers and 18 smokers). Psychiatric history was obtained by psychological autopsy. TPH2 mRNA was greater in suicide nonsmokers than suicide smokers, control smokers and control nonsmokers (p = 0.006). There was more TPH2 mRNA throughout the DRN. Smoking interferes with the TPH2 mRNA increase observed in suicide nonsmokers. The absence of altered TPH2 expression in non-suicide smokers suggests no pharmacological effect of smoking.

Synthesis and in vitro evaluation of [18F]FECIMBI-36: A potential agonist PET ligand for 5-HT2A/2C receptors.

Radiosynthesis and in vitro evaluation of [(18)F]-2-(4-bromo-2,5-dimethoxyphenyl)-N-(2-(2-fluoroethoxy)benzyl)ethanamine, ([(18)F]FECIMBI-36) or ([(18)F]1), a potential agonist PET imaging agent for 5-HT2A/2C receptors is described. Syntheses of reference standard 1 and the corresponding des-fluoroethyl radiolabeling precursor (2) were achieved with 75% and 65% yields, respectively. In vitro pharmacology assay of FECIMBI-36 by [(3)H]-ketanserin competition binding assay obtained from NIMH-PDSP showed high affinities to 5-HT2AR (Ki = 1nM) and 5-HT2CR (Ki=1.7 nM). Radiolabeling of FECIMBI-36 was achieved from the boc-protected precursor 2 using [(18)F]-fluoroethyltosylate in presence of Cs2CO3 in DMSO followed by removal of the protective group. [(18)F]1 was isolated using RP-HPLC in 25 ± 5% yield, purity > 95% and specific activity 1-2Ci/µmol (N = 6). In vitro autoradiography studies demonstrate that [(18)F]1 selectively label 5-HT2A and 5-HT2C receptors in slide-mounted sections of postmortem human brain using phosphor imaging. Our results indicate the potential of [(18)F]1 for imaging 5-HT2A/2C receptors in the high affinity state in vivo using PET imaging.

Alcoholics have more tryptophan hydroxylase 2 mRNA and protein in the dorsal and median raphe nuclei.

BACKGROUND: Chronic alcohol use depletes brain serotonin (5-hydroxytryptamine [5-HT]), yet we previously found more tryptophan hydroxylase 2 (TPH2), the rate-limiting biosynthetic enzyme for 5-HT, in the dorsal raphe nucleus (DRN) of alcoholics. We sought to determine whether the increase in amount of TPH2 enzyme is associated with more TPH2 mRNA gene expression in the DRN of a new cohort of alcoholics and controls. METHODS: TPH2 mRNA and protein were measured by in situ hybridization and immunoautoradiography, respectively, in the DRN and median raphe nucleus (MRN) of age- and sex-matched pairs (n = 16) of alcoholics and nonpsychiatric controls. Alcohol use disorder diagnosis and medical, psychiatric, and family histories were obtained by psychological autopsy. Age and sex were covariates in the analyses. RESULTS: TPH2 mRNA in alcoholics was greater in the DRN and MRN compared to controls (DRN: controls: 3.6 ± 1.6, alcoholics: 4.8 ± 1.8 nCi/mg of tissue, F = 4.106, p = 0.02; MRN: controls: 2.6 ± 1.2, alcoholics: 3.5 ± 1.1 nCi/mg of tissue, F = 3.96, p = 0.024). The difference in TPH2 mRNA was present in all DRN subnuclei (dorsal [DRd]: 135%, interfascicular [DRif]: 139%, ventral [DRv]: 135%, ventrolateral [DRvl]: 136% of control p < 0.05) except the caudal subnucleus. Alcoholics also had more TPH2 protein in the DRN and MRN than controls (DRN: controls: 265 ± 47, alcoholics: 318 ± 47 µCi/g, F = 8.72, p = 0.001; MRN: controls: 250 ± 33, alcoholics: 345 ± 39 µCi/g, F = 7.78, p = 0.001). There is a positive correlation between TPH2 protein and mRNA expression in the DRN (r = 0.815, p < 0.001), suggesting that the higher amount of TPH2 protein is due to an increase in TPH2 gene expression. CONCLUSIONS: These findings suggest that greater TPH2 gene expression is the basis for more TPH2 protein in the DRN and MRN in alcoholics.

Elevated serotonin and 5-HIAA in the brainstem and lower serotonin turnover in the prefrontal cortex of suicides.

Using high pressure liquid chromatography, we find more brainstem 5-HT and 5-HIAA in suicides compared with nonpsychiatric, sudden death controls throughout the rostrocaudal extent of the brainstem DRN and MRN. This suggests that 5-HT synthesis in suicides is greater within all DRN subnuclei and the MRN compared with controls.

Identifying novel phenotypes of vulnerability and resistance to activity-based anorexia in adolescent female rats.

OBJECTIVE: Activity-based anorexia is a translational rodent model that results in severe weight loss, hyperactivity, and voluntary self-starvation. The goal of our investigation was to identify vulnerable and resistant phenotypes of activity-based anorexia in adolescent female rats. METHOD: Sprague-Dawley rats were maintained under conditions of restricted access to food (N = 64; or unlimited access, N = 16) until experimental exit, predefined as a target weight loss of 30-35% or meeting predefined criteria for animal health. Nonlinear mixed effects statistical modeling was used to describe wheel running behavior, time to event analysis was used to assess experimental exit, and a regressive partitioning algorithm was used to classify phenotypes. RESULTS: Objective criteria were identified for distinguishing novel phenotypes of activity-based anorexia, including a vulnerable phenotype that conferred maximal hyperactivity, minimal food intake, and the shortest time to experimental exit, and a resistant phenotype that conferred minimal activity and the longest time to experimental exit. DISCUSSION: The identification of objective criteria for defining vulnerable and resistant phenotypes of activity-based anorexia in adolescent female rats provides an important framework for studying the neural mechanisms that promote vulnerability to or protection against the development of self-starvation and hyperactivity during adolescence. Ultimately, future studies using these novel phenotypes may provide important translational insights into the mechanisms that promote these maladaptive behaviors characteristic of anorexia nervosa.

Synthesis and in vitro evaluation of [18F]BMS-754807: a potential PET ligand for IGF-1R.

Radiosynthesis and in vitro evaluation of [(18)F](S)-1-(4-((5-cyclopropyl-1H-pyrazol-3-yl)amino)pyrrolo[2,1-f][1,2,4]triazin-2-yl)-N-(6-fluoropyridin-3-yl)-2-methylpyrrolidine-2-carboxamide ([(18)F]BMS-754807 or [(18)F]1) a specific IGF-1R inhibitor was performed. [(18)F]1 demonstrated specific binding in vitro to human cancer tissues. Synthesis of reference standard 1 and corresponding bromo derivative (1a), the precursor for radiolabeling were achieved from 2,4-dichloropyrrolo[2,1-f][1,2,4]triazine (4) in three steps with 50% overall yield. The radioproduct was obtained in 8% yield by reacting 1a with [(18)F]TBAF in DMSO at 170°C at high radiochemical purity and specific activity (1-2Ci/µmol, N=10). The proof of concept of IGF-IR imaging with [(18)F]1 was demonstrated by in vitro autoradiography studies using pathologically identified surgically removed grade IV glioblastoma, breast cancer and pancreatic tumor tissues. These studies indicate that [(18)F]1 can be a potential PET tracer for monitoring IGF-1R.

Autoradiographic evaluation of [3H]CUMI-101, a novel, selective 5-HT1AR ligand in human and baboon brain.

[11C]CUMI-101 is the first selective serotonin receptor (5-HT1AR) partial agonist radiotracer for positron emission tomography (PET) tested in vivo in nonhuman primates and humans. We evaluated specific binding of [3H]CUMI-101 by quantitative autoradiography studies in postmortem baboon and human brain sections using the 5-HT1AR antagonist WAY-100635 as a displacer. The regional and laminar distributions of [3H]CUMI-101 binding in baboon and human brain sections matched the known distribution of [3H]8-OH-DPAT and [3H]WAY-100635. Prazosin did not measurably displace [3H]CUMI-101 binding in baboon or human brain sections, thereby ruling out [3H]CUMI-101 binding to α1-adrenergic receptors. This study demonstrates that [11C]CUMI-101 is a selective 5-HT1AR ligand for in vivo and in vitro studies in baboon and human brain.