Project description:Hyperglycemia is a hallmark in prediabetes and type 2 diabetes mellitus (T2DM) which increases risk of micro and macrovascular complications such as diabetic retinopathy, diabetic nephropathy (microvascular complications), and peripheral vascular disease, cerebrovascular disease and cardiovascular diseases (macrovascular complications). Endothelial cells are affected in both cases. In this study, we investigated the miRNA expression changes in HUVECs during different glucose treatment (5mM, 10mM, 25mM and 40mM glucose) at various time intervals (6, 12, 24 and 48hrs). The results of miRNA microarray showed there is a correlation between hyperglycemia induced endothelial dysfunction and miRNA expression. In silico prediction showed that the following pathways: Regulation of actin cytoskeleton, PI3K-Akt signaling pathway, Apoptosis, Neurotrophin signaling pathway, and Insulin signaling pathway, were dysregulated during hyperglycemia. Majority of the pathways are related to apoptosis. 10 miRNAs (miR-26a-5p, -26b-5p, 29b-3p, 29c-3p, 125b-1-3p, -130b-3p, - 140-5p, -221-3p, -192-5p, and -320a,) showed increased expression with increasing concentration of glucose treatment. miR-26a-5p, -29b-3p, - 140-5p, -221-3p, and -192-5p are involves in endothelial apoptosis. Our study revealed miRNAs (miR-29b-3p and – 192-5p) with known mRNA targets (BCL2 and MCL1) showed expression pattern inversely correlating with their respective target mRNAs. Therefore these miRNAs could involve in the endothelial dysfunction due to hyperglycemia.
Project description:Cystic Fibrosis Related Diabetes (CFRD), the main co-morbidity in Cystic Fibrosis (CF), is associated with higher rates of lung function decline. We hypothesize that airway epithelial barrier function is impaired in CF and is further exacerbated under hyperglycemia, worsening pulmonary outcomes. Using 16HBE cells as a model cell line, we studied the effects of hyperglycemia in airway epithelial barrier function. Results show increased paracellular dye flux in CF cells in response to insulin treatment under hyperglycemia, suggesting impaired barrier integrity. Gene expression experiments identified Claudin-4 (CLDN4) as a key tight junction protein dysregulated in CF cells. Further investigation into CLDN4 protein localization by confocal microscopy showed that CLDN4 was tightly localized at tight junctions in WT cells and localization did not change under hyperglycemia. ln contrast, CLDN4 was less well-localized in CF cells at normal glucose and localization was worsened in CF cells conditioned to hyperglycemia. Treatment with highly effective modulator compounds (ETI) reversed this trend, and CFTR rescue by ETI in CF cells was not affected by insulin treatment or hyperglycemia. Bulk RNA sequencing showed differences in transcriptional responses in CF compared to WT cells under normal or high glucose, highlighting PTPRG as a promising target for further investigation.
Project description:Using DropSeq single cell RNA sequencing, we report that neuronal derived-IL-18 is required for goblet cell expression of intestinal antimicrobial protein expression Mucosal barrier immunity is essential for the maintenance of the commensal microflora and combating invasive bacterial infection. Although immune and epithelial cells are thought to be the canonical orchestrators of this complex equilibrium, here we show that the enteric nervous system (ENS) plays an essential and non-redundant role in governing the anti-microbial protein (AMP) response. Using confocal microscopy and single-molecule fluorescence in situ mRNA-hybridization (smFISH) studies, we observed that intestinal neurons produce the pleiotropic cytokine IL-18. Strikingly, deletion of IL-18 from the enteric neurons alone, but not immune or epithelial cells, rendered mice susceptible to invasive Salmonella typhimurium (S.t.) infection. Mechanistically, unbiased RNA sequencing and single cell sequencing revealed that enteric neuronal IL-18 is specifically required for homeostatic goblet cell AMP production. Together, we show that neuron derived IL-18 signaling controls tissue wide intestinal immunity and has profound consequences on the mucosal barrier and invasive bacterial killing.
Project description:Using RNA sequencing, we report that neuron derived-IL-18 is required for intestinal antimicrobial protein expression Mucosal barrier immunity is essential for the maintenance of the commensal microflora and combating invasive bacterial infection. Although immune and epithelial cells are thought to be the canonical orchestrators of this complex equilibrium, here we show that the enteric nervous system (ENS) plays an essential and non-redundant role in governing the anti-microbial protein (AMP) response. Using confocal microscopy and single-molecule fluorescence in situ mRNA-hybridization (smFISH) studies, we observed that intestinal neurons produce the pleiotropic cytokine IL-18. Strikingly, deletion of IL-18 from the enteric neurons alone, but not immune or epithelial cells, rendered mice susceptible to invasive Salmonella typhimurium (S.t.) infection. Mechanistically, unbiased RNA sequencing and single cell sequencing revealed that enteric neuronal IL-18 is specifically required for homeostatic goblet cell AMP production. Together, we show that neuron derived IL-18 signaling controls tissue wide intestinal immunity and has profound consequences on the mucosal barrier and invasive bacterial killing.
Project description:Environmental enteric dysfunction (EED), a chronic diffuse inflammation of the small intestine, is associated with stunting in children in the developing world. The pathobiology of EED is poorly understood because of the lack of a method to elucidate the host response. This study utilized a novel microarray method to interrogate the host transcriptome in feces in Malawian children with EED. Our data showed that the children studied had a range of %L values, consistent a spectrum of EED from normal to severe. We identified 12 transcripts associated with the severity of EED, including chemokines that stimulate T-cell proliferation, Fc fragments of multiple immunoglobulin families, interferon-induced proteins, activators of neutrophils and B-cells, and mediators that dampen cellular responses to hormones. EED associated transcripts mapped to pathways related to cell adhesion, and responses to a broad spectrum of viral, bacterial and parasitic microbes and enhanced phagocytosis. Several mucins, regulatory factors and protein kinases associated with the maintenance of the mucous layer were expressed less in children with EED than normal children. In conclusion, EED represents the focused activation of elements of the immune system and is associated with widespread intestinal barrier disruption. The differentially expressed transcripts may be explored as potential biomarkers. In 259 children, EED was measured by lactulose permeability (%L) in the small intestine. After isolating low copy numbers of mRNA, the transcriptome was reliably and reproducibly profiled. mRNA copy number was correlated with %L using analyses of covariance. The transcripts identified were mapped to biological pathways and processes.
Project description:Probiotics have become promising strategies for treating intestinal barrier dysfunction. However, the mechanisms by which probiotic bacteria interact with host cells to elicit beneficial effects remain unclear. Herein, we demonstrate that administration of E. coli Nissle 1917 (EcN) before Salmonella Typhimurium (STm) infection significantly suppressed STm pathogenesis in a mouse model. To address how bacterial interactions with intestinal epithelium affect STm infectivity, we developed a human gut-on-chip model coupled with computational fluid dynamics simulations, which recapitulated in vivo intestinal barrier protective phenotypes under physiologically relevant flow conditions. Using quantitative proteomics, we discovered that EcN-derived outer membrane protein MipA mediates protection by directly binding to intestinal epithelial integrin, inducing upregulation of integrin-linked kinase (ILK) to strengthen tight junctions and block STm invasion. Notably, expression of MipA in non-pathogenic STm conferred comparable barrier protection, establishing its pivotal role as a barrier enhancer. Our finding uncovers a novel mechanism whereby the bacterial membrane protein acts as a molecular trigger to enhance intestinal epithelial integrity, providing a significant framework for probiotic interventions against enteric infections.
Project description:Malnutrition is a major global health challenge that increases intestinal permeability and susceptibility to sepsis, yet the mechanisms driving barrier dysfunction remain poorly defined. We aimed to identify how the gut microbiome and microbiota-derived metabolites regulate intestinal barrier integrity during malnutrition. We used a low-protein, low-fat diet (LPLFD) to induce malnutrition in specific pathogen-free (SPF) and germ-free (GF) mice. Colonic permeability and mucus thickness were quantified. Metabolomics identified microbiota-derived metabolites altered by malnutrition. Human colonoids were used to test mechanistic effects of candidate metabolites. Barrier restoration was evaluated following colonic administration of isovalerate or oral supplementation with its precursor amino acid, leucine. LPLFD-induced malnutrition increased colonic permeability and reduced mucus thickness in male, but not female, SPF mice. These defects were absent in malnourished GF mice, indicating a microbiota-dependent and sexually dimorphic mechanism of barrier disruption. Metabolomic analysis revealed reduced colonic levels of branched-chain fatty acids (BCFAs) in malnourished mice. Supplementation of human colonoids with the BCFA isovalerate improved barrier function and altered expression of genes associated with epithelial junctional complexes. Restoring isovalerate levels, either directly via colonic administration or indirectly through oral leucine supplementation, partially rescued barrier defects in malnourished male mice. These findings identify BCFAs, particularly isovalerate, as essential microbiota-derived regulators of intestinal barrier integrity during malnutrition. This work reveals a sex-specific, microbiota-dependent pathway of barrier dysfunction and highlights microbial metabolites as promising therapeutic targets for mitigating sepsis risk in undernourished populations.
Project description:Proteomic study on the protective effect of black wolfberry polysaccharide extract on high blood glucose induced damage to enteric glial cells