Effect of Pharmacogenomic Testing for Drug-Gene Interactions on Medication Selection and Remission of Symptoms in Major Depressive Disorder: The PRIME Care Randomized Clinical Trial.

Importance: Selecting effective antidepressants for the treatment of major depressive disorder (MDD) is an imprecise practice, with remission rates of about 30% at the initial treatment. Objective: To determine whether pharmacogenomic testing affects antidepressant medication selection and whether such testing leads to better clinical outcomes. Design, Setting, and Participants: A pragmatic, randomized clinical trial that compared treatment guided by pharmacogenomic testing vs usual care. Participants included 676 clinicians and 1944 patients. Participants were enrolled from 22 Department of Veterans Affairs medical centers from July 2017 through February 2021, with follow-up ending November 2021. Eligible patients were those with MDD who were initiating or switching treatment with a single antidepressant. Exclusion criteria included an active substance use disorder, mania, psychosis, or concurrent treatment with a specified list of medications. Interventions: Results from a commercial pharmacogenomic test were given to clinicians in the pharmacogenomic-guided group (n = 966). The comparison group received usual care and access to pharmacogenomic results after 24 weeks (n = 978). Main Outcomes and Measures: The co-primary outcomes were the proportion of prescriptions with a predicted drug-gene interaction written in the 30 days after randomization and remission of depressive symptoms as measured by the Patient Health Questionnaire-9 (PHQ-9) (remission was defined as PHQ-9 ≤ 5). Remission was analyzed as a repeated measure across 24 weeks by blinded raters. Results: Among 1944 patients who were randomized (mean age, 48 years; 491 women [25%]), 1541 (79%) completed the 24-week assessment. The estimated risks for receiving an antidepressant with none, moderate, and substantial drug-gene interactions for the pharmacogenomic-guided group were 59.3%, 30.0%, and 10.7% compared with 25.7%, 54.6%, and 19.7% in the usual care group. The pharmacogenomic-guided group was more likely to receive a medication with a lower potential drug-gene interaction for no drug-gene vs moderate/substantial interaction (odds ratio [OR], 4.32 [95% CI, 3.47 to 5.39]; P < .001) and no/moderate vs substantial interaction (OR, 2.08 [95% CI, 1.52 to 2.84]; P = .005) (P < .001 for overall comparison). Remission rates over 24 weeks were higher among patients whose care was guided by pharmacogenomic testing than those in usual care (OR, 1.28 [95% CI, 1.05 to 1.57]; P = .02; risk difference, 2.8% [95% CI, 0.6% to 5.1%]) but were not significantly higher at week 24 when 130 patients in the pharmacogenomic-guided group and 126 patients in the usual care group were in remission (estimated risk difference, 1.5% [95% CI, -2.4% to 5.3%]; P = .45). Conclusions and Relevance: Among patients with MDD, provision of pharmacogenomic testing for drug-gene interactions reduced prescription of medications with predicted drug-gene interactions compared with usual care. Provision of test results had small nonpersistent effects on symptom remission. Trial Registration: ClinicalTrials.gov Identifier: NCT03170362.

Genome-wide DNA methylomic differences between dorsolateral prefrontal and temporal pole cortices of bipolar disorder.

Dorsolateral prefrontal cortex (DLPFC) and temporal pole (TP) are brain regions that display abnormalities in bipolar disorder (BD) patients. DNA methylation - an epigenetic mechanism both heritable and sensitive to the environment - may be involved in the pathophysiology of BD. To study BD-associated DNA methylomic differences in these brain regions, we extracted genomic DNA from the postmortem tissues of Brodmann Area (BA) 9 (DLPFC) and BA38 (TP) gray matter from 20 BD, ten major depression (MDD), and ten control age-and-sex-matched subjects. Genome-wide methylation levels were measured using the 850 K Illumina MethylationEPIC BeadChip. We detected striking differences between cortical regions, with greater numbers of between-brain-region differentially methylated positions (DMPs; i.e., CpG sites) in all groups, most pronounced in the BD group, and with substantial overlap across groups. The genes of DMPs common to both BD and MDD (hypothetically associated with their common features such as depression) and those distinct to BD (hypothetically associated with BD-specific features such as mania) were enriched in pathways involved in neurodevelopment including axon guidance. Pathways enriched only in the BD-MDD shared list pointed to GABAergic dysregulation, while those enriched in the BD-only list suggested glutamatergic dysregulation and greater impact on synaptogenesis and synaptic plasticity. We further detected group-specific between-brain-region gene expression differences in ODC1, CALY, GALNT2, and GABRD, which contained significant between-brain-region DMPs. In each brain region, no significant DMPs or differentially methylated regions (DMRs) were found between diagnostic groups. In summary, the methylation differences between DLPFC and TP may provide molecular targets for further investigations of genetic and environmental vulnerabilities associated with both unique and common features of various mood disorders and suggest directions of future development of individualized treatment strategies.

Basolateral amygdala volume and cell numbers in major depressive disorder: a postmortem stereological study.

Functional imaging studies consistently report abnormal amygdala activity in major depressive disorder (MDD). Neuroanatomical correlates are less clear: imaging studies have produced mixed results on amygdala volume, and postmortem neuroanatomic studies have only examined cell densities in portions of the amygdala or its subregions in MDD. Here, we present a stereological analysis of the volume of, and the total number of, neurons, glia, and neurovascular (pericyte and endothelial) cells in the basolateral amygdala in MDD. Postmortem tissues from 13 subjects with MDD and 10 controls were examined. Sections (~15/subject) taken throughout the rostral-caudal extent of the basolateral amygdala (BLA) were stained for Nissl substance and utilized for stereological estimation of volume and cell numbers. Results indicate that depressed subjects had a larger lateral nucleus than controls and a greater number of total BLA neurovascular cells than controls. There were no differences in the number or density of neurons or glia between depressed and control subjects. These findings present a more detailed picture of BLA cellular anatomy in depression than has previously been available. Further studies are needed to determine whether the greater number of neurovascular cells in depressed subjects may be related to increased amygdala activity in depression.

Altered expression of synapse and glutamate related genes in post-mortem hippocampus of depressed subjects.

Major depressive disorder (MDD) has been linked to changes in function and activity of the hippocampus, one of the central limbic regions involved in regulation of emotions and mood. The exact cellular and molecular mechanisms underlying hippocampal plasticity in response to stress are yet to be fully characterized. In this study, we examined the genetic profile of micro-dissected subfields of post-mortem hippocampus from subjects diagnosed with MDD and comparison subjects matched for sex, race and age. Gene expression profiles of the dentate gyrus and CA1 were assessed by 48K human HEEBO whole genome microarrays and a subgroup of identified genes was confirmed by real-time polymerase chain reaction (qPCR). Pathway analysis revealed altered expression of several gene families, including cytoskeletal proteins involved in rearrangement of neuronal processes. Based on this and evidence of hippocampal neuronal atrophy in MDD, we focused on the expression of cytoskeletal, synaptic and glutamate receptor genes. Our findings demonstrate significant dysregulation of synaptic function/structure related genes SNAP25, DLG2 (SAP93), and MAP1A, and 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid receptor subunit genes GLUR1 and GLUR3. Several of these human target genes were similarly dysregulated in a rat model of chronic unpredictable stress and the effects reversed by antidepressant treatment. Together, these studies provide new evidence that disruption of synaptic and glutamatergic signalling pathways contribute to the pathophysiology underlying MDD and provide interesting targets for novel therapeutic interventions.

Hippocampal volume and total cell numbers in major depressive disorder.

Neuroimaging consistently reveals smaller hippocampal volume in recurrent or chronic major depressive disorder (MDD). The underlying cellular correlates of the smaller volume are not clearly known. Postmortem tissues from 17 pairs of depressed and control subjects were obtained at autopsy, and informant-based retrospective psychiatric assessment was performed. Formalin-fixed left temporal lobes were sectioned (40 µm), stained for Nissl substance, and every 60th section selected throughout the entire hippocampus. Total volume of the hippocampal formation was calculated, and total numbers of pyramidal neurons (in hippocampal fields CA1, CA2/3, hilus), dentate gyrus (DG) granule cells, and glial cells were estimated stereologically. While hippocampal volume in all MDD subjects was not significantly smaller versus control subjects, in recurrent/chronic MDD, total volume decreased with duration of depressive illness (r = -0.696, p < 0.026). There was no significant difference between MDD and controls in total number or density of pyramidal neurons/granule cells or glial cells in CA1, CA2/3, hilus, or DG. However, CA1 pyramidal neuron density increased with duration of illness in recurrent/chronic MDD (r = 0.840, p < 0.002). Granule cell (r = 0.971, p < 0.002) and glial cell numbers (r = 0.980, p < 0.001) increased with age in those taking antidepressant medication (n = 6). Increasing DG granule cell and glial cell numbers with age in antidepressant-treated subjects may reflect proliferative effects of antidepressant medications. Decreasing total volume and increasing CA1 pyramidal neuron density with duration of illness in recurrent/chronic MDD lends support to the neuropil hypothesis of MDD.

Morphometric analysis of vascular pathology in the orbitofrontal cortex of older subjects with major depression.

OBJECTIVE: Late-life depression has been associated with risk for cerebrovascular pathology, as demonstrated in neuroimaging studies of older depressed patients, as well as mood disorder following cerebrovascular accidents. However, more research is needed on neuroanatomical changes in late-life depression, where there has been no clearly documented link to brain injury. Such studies should examine morphological changes in medium and small sized vessels that supply the cortical gray and white matter. METHODS: The present study used a non-specific histological Nissl staining and a more vessel-specific immunolabeling with endothelial marker von Willebrand Factor (vWF) to estimate density and size of blood vessel segments in the orbitofrontal cortex of 16 older subjects with major depressive disorder (MDD) and 9 non-psychiatric comparison subjects. RESULTS: The density of Nissl-stained vessel segments and of segments with perivascular spaces was higher in subjects with MDD than in comparison subjects in gray (GM) and white matter (WM). In GM, the density of vWF-immunoreactive segments with cross-sectional areas greater than 800 µm2 was higher in MDD. In WM, only the density of vWF-immunoreactive segments with patent perivascular spaces and diameters larger than 60 µm was higher in subjects with MDD. Also in the WM, only subjects with late-onset MDD presented a significantly higher density of vWF-positive segments than comparison subjects. CONCLUSIONS: In older subjects with MDD, there appear to be morphological changes that increase visibility of medium-sized vessel segments with some labeling techniques, and this increased visibility may be related to increased patency of perivascular spaces around arterioles.

Quantitative analysis of focused a-to-I RNA editing sites by ultra-high-throughput sequencing in psychiatric disorders.

A-to-I RNA editing is a post-transcriptional modification of single nucleotides in RNA by adenosine deamination, which thereby diversifies the gene products encoded in the genome. Thousands of potential RNA editing sites have been identified by recent studies (e.g. see Li et al, Science 2009); however, only a handful of these sites have been independently confirmed. Here, we systematically and quantitatively examined 109 putative coding region A-to-I RNA editing sites in three sets of normal human brain samples by ultra-high-throughput sequencing (uHTS). Forty of 109 putative sites, including 25 previously confirmed sites, were validated as truly edited in our brain samples, suggesting an overestimation of A-to-I RNA editing in these putative sites by Li et al (2009). To evaluate RNA editing in human disease, we analyzed 29 of the confirmed sites in subjects with major depressive disorder and schizophrenia using uHTS. In striking contrast to many prior studies, we did not find significant alterations in the frequency of RNA editing at any of the editing sites in samples from these patients, including within the 5HT(2C) serotonin receptor (HTR2C). Our results indicate that uHTS is a fast, quantitative and high-throughput method to assess RNA editing in human physiology and disease and that many prior studies of RNA editing may overestimate both the extent and disease-related variability of RNA editing at the sites we examined in the human brain.

Vascular and extravascular immunoreactivity for intercellular adhesion molecule 1 in the orbitofrontal cortex of subjects with major depression: age-dependent changes.

BACKGROUND: Vascular and immune alterations in the prefrontal cortex may contribute to major depression in elderly subjects. Intercellular adhesion molecule-1 (ICAM-1), major inflammatory mediator in vessels and astrocytes, could be altered in geriatric depression, but little is known about its age-dependent expression in subjects with depression and its relationship to astrocytes identified by the marker glial fibrillary acidic protein (GFAP), found to be reduced in depression. METHODS: We measured the percentage of gray matter area fraction covered by ICAM-1 immunoreactivity in blood vessels and in extravascular accumulations of ICAM-1 immunoreactivity in 19 non-psychiatric comparison subjects and 18 subjects with major depression, all characterized by postmortem psychological diagnosis. Association of extravascular ICAM-1 to GFAP-positive astrocytes was investigated by double-labeling immunofluorescence. RESULTS: Vascular and extravascular fractions of ICAM-1 immunoreactivity were lower in subjects with MDD than in non-psychiatric comparison subjects. Non-psychiatric comparison subjects older than 60 experienced dramatic increase in extravascular ICAM-1 immunoreactivity, but this increase was attenuated in elderly subjects with MDD, particularly in those dying by suicide. Most extracellular ICAM-1 immunoreactivity was coextensive with GFAP-immunoreactive astrocytes in both groups. LIMITATIONS: Heterogeneity in type and dosage of antidepressant medication. Difficulty in determining the exact onset of depression in subjects older than 60 at the time of death. Routine cerebrovascular pathological screening may miss subtle subcellular and molecular changes. CONCLUSIONS: There is significant attenuation of extravascular and vascular ICAM-1 immunoreactivity in elderly subjects with major depression suggesting an astrocyte-associated alteration in immune function in the aging orbitofrontal cortex of subjects with MDD.

A novel role for glyceraldehyde-3-phosphate dehydrogenase and monoamine oxidase B cascade in ethanol-induced cellular damage.

BACKGROUND: Alcoholism is a major psychiatric condition at least partly associated with ethanol (EtOH)-induced cell damage. Although brain cell loss has been reported in subjects with alcoholism, the molecular mechanism is unclear. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and monoamine oxidase B (MAO B) reportedly play a role in cellular dysfunction under stressful conditions and might contribute to EtOH-induced cell damage. METHODS: Expression of GAPDH and MAO B protein was studied in human glioblastoma and neuroblastoma cell lines exposed to physiological concentrations of EtOH. Expression of these proteins was also examined in the prefrontal cortex from human subjects with alcohol dependence and in rats fed with an EtOH diet. Coimmunoprecipitation, subcellular fractionation, and luciferase assay were used to address nuclear GAPDH-mediated MAO B activation. To test the effects of inactivation, RNA interference and pharmacological intervention were used, and cell damage was assessed by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP Nick End Labeling (TUNEL) and hydrogen peroxide measurements. RESULTS: Ethanol significantly increases levels of GAPDH, especially nuclear GAPDH, and MAO B in neuronal cells as well as in human and rat brains. Nuclear GAPDH interacts with the transcriptional activator, transforming growth factor-beta-inducible early gene 2 (TIEG2), and augments TIEG2-mediated MAO B transactivation, which results in cell damage in neuronal cells exposed to EtOH. Knockdown expression of GAPDH or treatment with MAO B inhibitors selegiline (deprenyl) and rasagiline (Azilect) can block this cascade. CONCLUSIONS: Ethanol-elicited nuclear GAPDH augments TIEG2-mediated MAO B, which might play a role in brain damage in subjects with alcoholism. Compounds that block this cascade are potential candidates for therapeutic strategies.

Gender-specific decrease in NUDR and 5-HT1A receptor proteins in the prefrontal cortex of subjects with major depressive disorder.

A variety of studies have documented alterations in 5-HT1A receptor binding sites in the brain of subjects with major depressive disorder (MDD). The recently identified transcription factor, nuclear deformed epidermal autoregulatory factor (NUDR/Deaf-1) has been shown to function as a transcriptional modulator of the human 5-HT1A receptor gene. The present study was undertaken to document the regional and cellular localization of NUDR in the human prefrontal cortex and to examine the levels of NUDR and 5-HT1A receptor protein in prefrontal cortex of female and male depressed and control subjects. NUDR immunoreactivity was present in neurons and glia across cortical layers and was co-localized with 5-HT1A receptor immunoreactive neurons. NUDR immunoreactivity as measured by Western blot was significantly decreased in the prefrontal cortex of female depressed subjects (42%, p=0.02) and unchanged in male depressed subjects relative to gender-matched control subjects. Similarly, 5-HT1A receptor protein level was significantly reduced in the prefrontal cortex of female depressed subjects (46%, p=0.03) and unchanged in male depressed subjects compared to gender-matched control subjects. Reduced protein expression of NUDR in the prefrontal cortex of female subjects with MDD may reflect a functional alteration in this transcription factor, which may contribute to the decrease in 5-HT1A receptors observed in the same female subjects with MDD. In addition, the gender-specific alterations in cortical NUDR and 5-HT1A receptor proteins could represent an underlying biological mechanism associated with the higher incidence of depression in women.

Gene expression profiling in postmortem prefrontal cortex of major depressive disorder.

Investigations of the molecular mechanisms underlying major depressive disorder (MDD) have been hampered by the complexity of brain tissue and sensitivity of gene expression profiling approaches. To address these issues, we used discrete microdissections of postmortem dorsolateral prefrontal cortex (DLPFC) (area 9) and an oligonucleotide (60mer) microarray hybridization procedure that increases sensitivity without RNA amplification. Mixed-effects statistical methods were used to rigorously control for medication usage in the subset of medicated depressed subjects. These analyses yielded a rich profile of dysregulated genes. Two of the most highly dysregulated genes of interest were stresscopin, a neuropeptide involved in stress responses, and Forkhead box D3 (FOXD3), a transcription factor. Secondary cell-based analysis demonstrated that stresscopin and FoxD3 are increased in neurons of DLPFC gray matter of MDD subjects. These findings identify abnormal gene expression in a discrete region of MDD subjects and contribute to further elucidation of the molecular alterations of this complex mood disorder.

Cellular changes in the postmortem hippocampus in major depression.

BACKGROUND: Imaging studies report that hippocampal volume is decreased in major depressive disorder (MDD). A cellular basis for reduced hippocampal volume in MDD has not been identified. METHODS: Sections of right hippocampus were collected in 19 subjects with MDD and 21 normal control subjects. The density of pyramidal neurons, dentate granule cell neurons, glia, and the size of the neuronal somal area were measured in systematic, randomly placed three-dimensional optical disector counting boxes. RESULTS: In MDD, cryostat-cut hippocampal sections shrink in depth a significant 18% greater amount than in control subjects. The density of granule cells and glia in the dentate gyrus and pyramidal neurons and glia in all cornv ammonis (CA)/hippocampal subfields is significantly increased by 30%-35% in MDD. The average soma size of pyramidal neurons is significantly decreased in MDD. CONCLUSION: In MDD, the packing density of glia, pyramidal neurons, and granule cell neurons is significantly increased in all hippocampal subfields and the dentate gyrus, and pyramidal neuron soma size is significantly decreased as well. It is suggested that a significant reduction in neuropil in MDD may account for decreased hippocampal volume detected by neuroimaging. In addition, differential shrinkage of frozen sections of the hippocampus suggests differential water content in hippocampus in MDD.