Project description:Alcohol consumption is known to lead to gene expression changes in the brain. After performing gene co-expression network analysis (WGCNA) of genome-wide mRNA and microRNA expressions in the Nucleus Accumbens (NAc) from subjects with alcohol dependence (AD) and matched controls six mRNA and three miRNA modules significantly correlated with AD after Bonferroni correction (adj. p≤ 0.05) were identified. Cell-type-specific transcriptome analysis revealed two of the mRNA modules to be enriched for neuronal specific marker genes and downregulated in AD, whereas the remaining four were enriched for astrocyte and microglial specific marker genes and were upregulated in AD. Using gene set enrichment analysis, the neuronal specific modules were enriched for genes involved in oxidative phosphorylation, mitochondrial dysfunction and MAPK signaling, while the glial-specific modules were enriched mostly for genes involved in processes related to immune functions, i.e. reactome cytokine signaling in immune system (all adj. p≤ 0.05). In the mRNA and miRNA modules, 461 and 25 candidate hub genes were identified, respectively. In contrast to the expected miRNAs’ biological functions, the correlation analyses between mRNA and miRNA hub genes revealed a significantly higher number of positive than negative correlations (chi-square p≤ 0.0001). At FDR≤ 0.1, integration of the mRNA and miRNA hubs genes expression with genome-wide genotypic data identified 591 cis-eQTLs and 62 cis-eQTLs for the mRNA and miRNA hubs, respectively. Adjusting for the number of tests, the mRNA cis-eQTLs were significantly enriched for AD GWAS signals in the Collaborative Study on Genetics of Alcohol (COGA) sample (adj. p=0.024), providing a novel biological role for these association signals. In conclusion, our study identified coordinated mRNA and miRNA co-expression changes in the NAc of AD subjects, and our genetic (cis-eQTL) analysis provides novel insights into the etiological mechanisms of AD.

Project description:Alcohol consumption is known to lead to gene expression changes in the brain. After performing gene co-expression network analysis (WGCNA) of genome-wide mRNA and microRNA expressions in the Nucleus Accumbens (NAc) from subjects with alcohol dependence (AD) and matched controls six mRNA and three miRNA modules significantly correlated with AD after Bonferroni correction (adj. p? 0.05) were identified. Cell-type-specific transcriptome analysis revealed two of the mRNA modules to be enriched for neuronal specific marker genes and downregulated in AD, whereas the remaining four were enriched for astrocyte and microglial specific marker genes and were upregulated in AD. Using gene set enrichment analysis, the neuronal specific modules were enriched for genes involved in oxidative phosphorylation, mitochondrial dysfunction and MAPK signaling, while the glial-specific modules were enriched mostly for genes involved in processes related to immune functions, i.e. reactome cytokine signaling in immune system (all adj. p? 0.05). In the mRNA and miRNA modules, 461 and 25 candidate hub genes were identified, respectively. In contrast to the expected miRNAs’ biological functions, the correlation analyses between mRNA and miRNA hub genes revealed a significantly higher number of positive than negative correlations (chi-square p? 0.0001). At FDR? 0.1, integration of the mRNA and miRNA hubs genes expression with genome-wide genotypic data identified 591 cis-eQTLs and 62 cis-eQTLs for the mRNA and miRNA hubs, respectively. Adjusting for the number of tests, the mRNA cis-eQTLs were significantly enriched for AD GWAS signals in the Collaborative Study on Genetics of Alcohol (COGA) sample (adj. p=0.024), providing a novel biological role for these association signals. In conclusion, our study identified coordinated mRNA and miRNA co-expression changes in the NAc of AD subjects, and our genetic (cis-eQTL) analysis provides novel insights into the etiological mechanisms of AD. Tissue samples were received from the Australian Brain Donor Programs New South Wales Tissue Resource Centre, which is supported by The University of Sydney, National Health and Medical Research Council of Australia, Schizophrenia Research Institute, National Institute of Alcohol Abuse and Alcoholism, and the New South Wales Department of Health. Cases were excluded if they had an infectious disease (i.e. HIV/AIDS, hepatitis B or C, or Creutzfeldt-Jakob disease), an unsatisfactory agonal status determined from the circumstances surrounding the death, post-mortem delays >48 hours, or significant head injury. In addition to case status, age, sex, ethnicity, brain weight, brain pH, post-mortem interval (PMI), tissue hemisphere, clinical cause of death, blood toxicology at time of death, smoking status, neuropathology and liver pathology were also provided for each subject. MiRNA and mRNA expression in 18 matched case-control pairs (N=36) with sample RINs ?6 were assessed on the Affymetrix GeneChip® Human Genome U133A 2.0 (HG-U133A 2.0) and Affymetrix GeneChip miRNA 3.0 microarray.

Project description:Gut dysbiosis and host genetics are implicated as causative factors in inflammatory bowel disease, yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically-created blind self-filling (SFL) and self-emptying (SEL) ileal loops. SFL exhibit fecal stasis due to directional peristalsis motility oriented towards away from the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL, develop pouch-like microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. Germ-free IL10-/- mice conventionalized with wild type SFL, but not SEL, microbiota, develop severe colitis. These data demonstrate an essential role for fecal stasis, gut dysbiosis, and genetic susceptibility and offer insights into human pouchitis and ulcerative colitis. All animal protocols were approved by IACUC at the University of Chicago. All animals were C57Bl/6 mice that were bred and housed under standard 12:12 light/dark conditions at the University of Chicago. Female mice aged 6-8 weeks were fed ad libitum gel diet 76A (Cat# 72-07-5022, Clear H20, Portland, ME) for 5-days prior to surgery to prevent obstruction at the anastomosis. Animals were anesthetized with ketamine/xylazine. Aseptic surgery was performed to resect 2.5cm of ileum 3cm proximal to the ileal-cecal value with anastomosis to the ileum using 8-0 suture (Figure 1a). The abdominal wall was closed with interrupted 4-0 silk suture and skin was closed with staples. Analgesics (betanorphine mg/kg BW) were provided post-operatively. After 5 weeks, mice were humanely euthanized. Intestinal loops were collected for RNA, protein, and histology. Loop, sham ileum, and sham colon contents were collected and snap frozen at −80°C for microbiota analysis. Human biopsies and stool samples were obtained under IRB approval and privacy protocols were followed. Our initial work demonstrated up regulation of TLR4 signaling in the mucosa of self-filling ileal loops. We hypothesized that TLR4 may be in-part responsible for mediating the metaplasia and inflammatory responses observed. Therefore, TLR4 KO mice were used to test this hypothesis and subsequently demonstrated attenuated responses in these parameters.

Dataset Information

Identification of cis-eQTLs in six immune cell types CD4, CD8, CD14,CD15, CD19, PLA and ileal, colonic and rectal biopsies in 323 healthy European individuals (CEDAR cohort).

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