A cardinal symptom of Major Depressive Disorder (MDD) is the disruption of circadian patterns. Yet, to date, there is no direct evidence of circadian clock dysregulation in the brains of MDD patients. Circadian rhythmicity of gene expression has been observed in animals and peripheral human tissues, but its presence and variability in the human brain was difficult to characterize. Here we applied time-of-death analysis to gene expression data from high-quality postmortem brains, examining 24-hour cyclic patterns in six cortical and limbic regions of 55 subjects with no history of psychiatric or neurological illnesses ('Controls') and 34 MDD patients. Our dataset covered ~12,000 transcripts in the dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (AnCg), hippocampus (HC), amygdala (AMY), nucleus accumbens (NAcc) and cerebellum (CB). Several hundred transcripts in each region showed 24-hour cyclic patterns in Controls, and >100 transcripts exhibited consistent rhythmicity and phase-synchrony across regions. Among the top ranked rhythmic genes were the canonical clock genes BMAL1(ARNTL), PER1-2-3, NR1D1(REV-ERB), DBP, BHLHE40(DEC1), and BHLHE41(DEC2). The phasing of known circadian genes was consistent with data derived from other diurnal mammals. Cyclic patterns were much weaker in MDD brains, due to shifted peak timing and potentially disrupted phase relationships between individual circadian genes. This is the first transcriptome-wide analysis of cyclic patterns in the human brain and demonstrates a rhythmic rise and fall of gene expression in regions outside of the suprachiasmatic nucleus in control subjects. The description of its breakdown in MDD suggest novel molecular targets for treatment of mood disorders.
Circadian patterns of gene expression in the human brain and disruption in major depressive disorder.
Subject
View SamplesRNA-seq profiling was conducted on clinically-annotated human post-mortem brain tissues Overall design: We measured the transcriptome in 281 clinically-annotated human post-mortem brain tissues
Post-mortem molecular profiling of three psychiatric disorders.
Sex, Specimen part, Race, Subject
View SamplesGender differences in brain development and in the prevalence of neuropsychiatric disorders such as depression have been reported. Gender differences in human brain might be related to patterns of gene expression. Microarray technology is one useful method for investigation of gene expression in brain. We investigated gene expression, cell types, and regional expression patterns of differentially expressed sex chromosome genes in brain. We profiled gene expression in male and female dorsolateral prefrontal cortex, anterior cingulate cortex, and cerebellum using the Affymetrix oligonucleotide microarray platform. Differentially expressed genes between males and females on the Y chromosome (DBY, SMCY, UTY, RPS4Y, and USP9Y) and X chromosome (XIST) were confirmed using real-time PCR measurements. In situ hybridization confirmed the differential expression of gender-specific genes and neuronal expression of XIST, RPS4Y, SMCY, and UTY in three brain regions examined. The XIST gene, which silences gene expression on regions of the X chromosome, is expressed in a subset of neurons. Since a subset of neurons express gender-specific genes, neural subpopulations may exhibit a subtle sexual dimorphism at the level of differences in gene regulation and function. The distinctive pattern of neuronal expression of XIST, RPS4Y, SMCY, and UTY and other sex chromosome genes in neuronal subpopulations may possibly contribute to gender differences in prevalence noted for some neuropsychiatric disorders. Studies of the protein expression of these sex-chromosome-linked genes in brain tissue are required to address the functional consequences of the observed gene expression differences.
Gender-specific gene expression in post-mortem human brain: localization to sex chromosomes.
No sample metadata fields
View SamplesNeonicotinoid insecticides control crop pests based on their action as agonists at the insect nicotinic acetylcholine receptor which accepts chloropyridinyl- and chlorothiazolyl- analogs almost equally well. In some cases, these compounds have also been reported to enhance plant vigor and (a)biotic stress tolerance, independent of their insecticidal function. However, this mode of action has not been specifically defined. Using Arabidopsis thaliana, we show that the neonicotinoid compounds, imidacloprid (IMI) and clothianidin (CLO), via their 6-chloropyridinyl-3-carboxylic acid and 2-chlorothiazolyl-5-carboxylic acid metabolites, respectively, induce salicylic acid (SA) associated plant responses. SA is a phytohormone best known for its role in plant defense against pathogens and as an inducer of systemic acquired resistance; however, it can also modulate abiotic stress responses. These neonicotinoids effect a similar global transcriptional response to that of SA including genes involved in (a)biotic stress response. Furthermore, similar to SA, IMI and CLO induce systemic acquired resistance resulting in reduced growth of a powdery mildew pathogen. The action of CLO induces the endogenous synthesis of SA via the SA biosynthetic enzyme ICS1, with ICS1 required for CLO-induced accumulation of SA, expression of the SA marker PR1, and fully enhanced resistance to powdery mildew. In contrast, the action of IMI does not induce endogenous synthesis of SA. Instead, IMI is further bioactivated to 6-chloro-2-hydroxypyridinyl-3-carboxylic acid, which is shown here to be a potent inducer of PR1 and inhibitor of SA-sensitive enzymes. Thus, via different mechanisms, these chloropyridinyl- and chlorothiazolyl- neonicotinoids induce SA responses associated with enhanced stress tolerance.
Neonicotinoid insecticides induce salicylate-associated plant defense responses.
Age, Specimen part
View SamplesGene expression patterns in the brain are strongly influenced by the severity of physiological stress at death. This agonal effect, if not well controlled, can lead to spurious findings in case-control comparisons. While many recent studies match samples by tissue pH and clinically recorded agonal conditions, we found that these commonly used indicators were sometimes at odds with observed stress-related patterns of gene expression, and that matching by these criteria still sometimes results in identifying differences between cases and controls that are primarily driven by residual agonal effects. This problem is analogous to the one in genetic studies, where race and ethnicity are often imprecise proxies for complex environmental and genetic factors.
Sample matching by inferred agonal stress in gene expression analyses of the brain.
Subject
View SamplesAnalysis of baseline gene expression in bone marrow derived dendritic cells (BMDC) from female CBA/J (CBA) and C57BL/6 (BL/6) mice. Results provide insight into strain-dependent differences in gene expression.
CD209a expression on dendritic cells is critical for the development of pathogenic Th17 cell responses in murine schistosomiasis.
Specimen part
View SamplesPro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNFalpha) and interleukin-1beta/alpha (IL1beta/alpha) modulate catecholamine secretion, and long-term gene regulation, in chromaffin cells of the adrenal medulla. Interleukin-6 (IL6), also released during inflammation, affects transcriptional responses in primary chromaffin cells, and may coordinate immune and autonomic adrenomedullary responses via an autocrine mechanism, as TNFalpha itself strongly induces IL6 expression in chromaffin cells, which in turn express receptors responsive to IL6. We have examined the signaling mechanisms employed by IL6 to affect tyrosine hydroxylase (TH) enzymatic activation, and adrenomedullary gene transcription, in cultured bovine chromaffin cells. IL6 caused acute tyrosine/threonine phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), and serine phosphorylation of signal transducer and activator of transcription 3 (STAT3), as do several other first messengers acting on the chromaffin cell, including histamine, nicotine and angiotensin II. IL6 uniquely activated tyrosine phosphorylation of STAT3. Consistent with a short-term ERK1/2 activation, IL6 treatment caused prompt regulation of TH phosphorylation, and up-regulation of genes encoding secreted proteins of the adrenal medulla including galanin, vasoactive intestinal peptide (VIP), gastrin releasing peptide (GRP) and parathyroid hormone-like hormone (PTHLH). We further examined the effects of IL6 treatment on the entire bovine chromaffin cell transcriptome. Of 90 genes up-regulated by IL6, only 16 of which are known targets of IL6 in the immune system. The remaining genes likely represent a combination of novel IL6/STAT3 targets, targets of ERK1/2 shared by other first messengers, and, potentially, IL6-dependent genes activated in a secondary cascade via transcription mediated by IL6-induced transcription factors, such as HIF-1alpha. Notably, genes induced by IL6 represent a cohort with a profile that includes both neuroendocrine-specific genes, including several that are activated by G-protein couple receptor (GPCR) signaling pathways initiated by histamine and pituitary adenylate cyclase-activating polypeptide (PACAP), and some transcripts also activated by cytokines including interferon-alpha (INFalpha and TNFalpha. These results suggest an integrative role for IL6 in overall fine-tuning of the chromaffin cell response to a wide range of physiological and paraphysiological stressors, particularly when immune and endocrine stimuli converge in the adrenal medulla.
Interleukin-6-mediated signaling in adrenal medullary chromaffin cells.
Specimen part
View SamplesEleven NSCLC cell lines with widely divergent gefitinib sensitivities were compared using gene expression. Genes associated with gefitinib response were used to classify additional NSCLC lines with unknown gefitnib sensitivity.
Baseline gene expression predicts sensitivity to gefitinib in non-small cell lung cancer cell lines.
No sample metadata fields
View SamplesThe targeting of oncogenic ‘driver’ kinases with small molecule inhibitors has proven to be a highly effective therapeutic strategy in selected non-small cell lung cancer (NSCLC) patients. However, acquired resistance to targeted therapies invariably arises and is a major limitation to patient care. ROS1 fusion proteins are a recently described class of oncogenic driver, and NSCLC patients that express these fusions generally respond well to ROS1-targeted therapy. In this study, we sought to determine mechanisms of acquired resistance to ROS1 inhibition. To accomplish this, we generated a ROS1 inhibition-resistant derivative of the initially sensitive NSCLC cell line HCC78.
Resistance to ROS1 inhibition mediated by EGFR pathway activation in non-small cell lung cancer.
No sample metadata fields
View SamplesLung tumors
Analysis of orthologous gene expression between human pulmonary adenocarcinoma and a carcinogen-induced murine model.
No sample metadata fields
View Samples