Epithelial Cell Junction Regulation by the Stress-Associated miR-150, miR-335, and miR-142-3p in the Absence or Presence of Chronic Dexamethasone

Authors

• SK Abey
• J Robinson
• NH Fourie
• NK Kenea
• D Wang
• T Vishnyakova
• W Henderson

Abstract

Differential expression of miR-150, miR-335, and miR-142-3p is found in circulating RNA of patients with chronic gastrointestinal dysfunction and high perceived psychological stress. This patient group also exhibited altered gut epithelial permeability in experiments in which patients ingested a sugar-based test solution and then tested for absorbed metabolites. In a rat model system, gut epithelial barrier dysfunction is shown to be mediated by systemic release of endogenous corticosterone during a psychological stress response. miR-150, miR-335, and miR-142-3p are known for targeting cytoskeletal regulators ROCK and RAC. Together, these previous findings indicate that gut epithelial permeability during stress may be related to regulation of actin cytoskeletal dynamics through the activity of microRNA (miRNA) gene regulation, however their effects on colonic barrier function and tight junction protein dynamics are not known. To test this, we used a colon epithelial cell culture, grown as adherent monolayer on a permeable membrane, to test the cellular effects of miRNA over-expression. We also exposed the monolayers to prolonged Dexamethasone exposure, to simulate chronic exposure to stress hormone. Measurements of trans-epithelial electrical resistance (TEER) were taken to quantify trans-epithelial barrier function, and immunofluorescence microscopy (IF) was used to detect localization of key proteins of the epithelial tight junction, Zona Occludens-1 (ZO1) and Occludin (OCLN). Our findings indicate that miR-142-3p overexpression has an overall negative effect on epithelial barrier function, while miR-150 and miR-335 may have complementary and positive effects which counteract the negative effects of miR-142-3p in a putative regulatory loop.

Scientific Focus Area: Cell Biology

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