Project description:MicroRNA (miRNA)-mediated mRNA regulation directs many homeostatic and pathological processes, but how miRNAs coordinate aberrant esophageal inflammation during eosinophilic esophagitis (EoE) is poorly understood. Here, we report a deregulatory axis where microRNA-155 (miR-155) regulates epithelial barrier dysfunction by selectively constraining tight junction CLDN7 (claudin-7). MiR-155 is elevated in the esophageal epithelium of biopsies from patients with active EoE and in cell culture models. miR-155 localisation using in situ hybridisation (ISH) in patient biopsies, and intra-epithelial compartmentalisation of miR-155 shows expression predominantly within the basal epithelia. Epithelial miR-155 activity was evident through diminished target gene expression in 3D organotypic cultures, particularly in relatively undifferentiated basal cell states. Mechanistically, generation of a novel cell line with enhanced epithelial miR-155 stable overexpression induced a functionally deficient epithelial barrier in 3D air-liquid interface epithelial cultures measured by transepithelial electrical resistance (TEER). Histological assessment of 3D esophageal organoid cultures overexpressing miR-155 showed notable dilated intra-epithelial spaces. Unbiased RNA-sequencing analysis and immunofluorescence determined a defect in epithelial barrier tight junctions and revealed a selective reduction in the expression of critical esophageal tight junction molecule, claudin-7. Together, our data reveal a previously unappreciated role for miR-155 in mediating epithelial barrier dysfunction in esophageal inflammation.
Project description:Over-expression of miR-155 induces changes in the pattern of gene expression of hCMEC/D3 cells. hypothesis tested in the present study was that miR-155 constitute an important regulatory control of the brain endothelial response to inflammatory cytokines. To identify miR-155 target genes in brain endothelim that might be implicated in BBB dysfunction relevant to human disease, we then analysed changes in mRNA expression of hCMEC/D3 cells that overexpress miR-155 and results were contrasted to cells transfected with scrambled miR. To ectopically express miR-155 in hCMEC/D3 cells, 30 nM of pre-miR-155 and the siPORT Amine transfection agent (Applied Biosystems, Warrington, UK) were combined following the manufacturerM-bM-^@M-^Ys instructions.
Project description:Intracerebral hemorrhage (ICH) induces alterations in the gut microbiota composition, significantly impacting neuroinflammation post-ICH. However, the impact of gut microbiota absence on neuroinflammation following ICH-induced brain injury remain unexplored. Here, we observed that the gut microbiota absence was associated with reduced neuroinflammation, alleviated neurological dysfunction, and mitigated gut barrier dysfunction post-ICH. In contrast, recolonization of microbiota from ICH-induced SPF mice by transplantation of fecal microbiota (FMT) exacerbated brain injury and gut impairment post-ICH. Additionally, microglia with transcriptional changes mediated the protective effects of gut microbiota absence on brain injury, with Apoe emerging as a hub gene. Subsequently, Apoe deficiency in peri-hematomal microglia was associated with improved brain injury. Finally, we revealed that gut microbiota influence brain injury and gut impairment via gut-derived short-chain fatty acids (SCFA).
Project description:The cellular microRNA, miR-155 has been shown to be involved in lymphocyte activation and is expressed in EBV infected cells displaying type III latency gene expression but not type I latency gene expression. We show here that the elevated levels of miR-155 in type III latency cells is due to EBV gene expression and not epigenetic differences in cell lines tested and we show that expression in EBV infected cells requires a conserved AP-1 element in the miR-155 promoter. Gene expression analysis was carried out in a type I latency cell line transduced with a miR-155 expressing retrovirus. This analysis identified both miR-155 suppressed and induced cellular mRNAs and suggested that in addition to direct targeting of 3’ UTRs, miR-155 alters gene expression in part through the alteration of signal transduction pathways. 3’ UTR reporter analysis of predicted miR-155 target genes identified the transcriptional regulatory genes, BACH1, ZIC3, HIVEP2, CEBPB, ZNF652, ARID2, and SMAD5 as miR-155 targets. Western blot analysis of the most highly suppressed of these, BACH1, showed lower expression in cells transduced with a miR-155 retrovirus. Inspection of the promoters from genes regulated in EBV infected cells and in cells infected with a miR-155 retrovirus identified potential binding sequences for BACH1 and ZIC3. Together, these experiments suggest that the induction of miR-155 by EBV contributes to EBV mediated signaling in part through the modulation of transcriptional regulatory factors. Keywords: Differential expression of miR-155 vs cntl expressing cells
Project description:Dysfunction of vascular endothelium is characteristic of many aging-related diseases, including Alzheimers disease (AD) and AD-related dementias (ADRD). While it is widely posited that endothelial cell dysfunction contributes to the pathogenesis and/or progression of AD/ADRD, it is not clear how. A plausible hypothesis is that intercellular trafficking of extracellular vesicles (EVs) from senescent vascular endothelial cells promotes vascular endothelial cell dysfunction. To test this hypothesis, we compared the expression of proteins and miRNAs in EVs isolated from early passage (EP) vs. senescent (SEN) primary human coronary artery endothelial cells (HCAECs) from the same donor. Proteomics and miRNA libraries constructed from these EV isolates were evaluated using FunRich gene ontology analysis to compare functional enrichment between EP and SEN endothelial cell EVs (ECEVs). Replicative senescence was associated with altered EV abundance and contents independent of changes in EV size. Unique sets of miRNAs and proteins were differentially expressed in SEN-ECEVs, including molecules related to cell adhesion, barrier integrity, receptor signaling, endothelial-mesenchymal transition and cell senescence. miR-181a-5p was the most upregulated miRNA in SEN-ECEVs, increasing >5-fold. SEN-ECEV proteomes supported involvement in several pro-inflammatory pathways consistent with senescence and the senescence-associated secretory phenotype (SASP). These data indicate that SEN-ECEVs are enriched in bioactive molecules implicated in senescence-associated vascular dysfunction, blood-brain barrier impairment, and AD/ADRD pathology. These observations suggest involvement of SEN-ECEVs in the pathogenesis of vascular dysfunction associated with AD/ADRD.
Project description:The cellular microRNA, miR-155 has been shown to be involved in lymphocyte activation and is expressed in EBV infected cells displaying type III latency gene expression but not type I latency gene expression. We show here that the elevated levels of miR-155 in type III latency cells is due to EBV gene expression and not epigenetic differences in cell lines tested and we show that expression in EBV infected cells requires a conserved AP-1 element in the miR-155 promoter. Gene expression analysis was carried out in a type I latency cell line transduced with a miR-155 expressing retrovirus. This analysis identified both miR-155 suppressed and induced cellular mRNAs and suggested that in addition to direct targeting of 3’ UTRs, miR-155 alters gene expression in part through the alteration of signal transduction pathways. 3’ UTR reporter analysis of predicted miR-155 target genes identified the transcriptional regulatory genes, BACH1, ZIC3, HIVEP2, CEBPB, ZNF652, ARID2, and SMAD5 as miR-155 targets. Western blot analysis of the most highly suppressed of these, BACH1, showed lower expression in cells transduced with a miR-155 retrovirus. Inspection of the promoters from genes regulated in EBV infected cells and in cells infected with a miR-155 retrovirus identified potential binding sequences for BACH1 and ZIC3. Together, these experiments suggest that the induction of miR-155 by EBV contributes to EBV mediated signaling in part through the modulation of transcriptional regulatory factors. Keywords: Gene expression analysis in EBV positive vs EBV negative cells