Seye, C. I. | Search bioRxiv

bioRxiv2021

Endothelial Pannexin 1-TRPV4 channel signaling lowers pulmonary arterial pressure

Pannexin 1 (Panx1) is an ATP-efflux channel that controls endothelial function in the systemic circulation. However, the roles of endothelial Panx1 in resistance-sized pulmonary arteries (PAs) are unknown. Extracellular ATP dilates PAs through activation of endothelial TRPV4 (transient receptor potential vanilloid 4) ion channels. We hypothesized that endothelial Panx1-ATP- TRPV4 channel signaling promotes vasodilation and lowers pulmonary arterial pressure (PAP). Endothelial, but not smooth muscle, knockout of Panx1 or TRPV4 increased PA contractility and raised PAP. Panx1-effluxed extracellular ATP signaled through purinergic P2Y2 receptor (P2Y2R) to activate protein kinase C (PKC), which in turn activated endothelial TRPV4 channels. Finally, caveolin-1 provided a signaling scaffold for endothelial Panx1, P2Y2R, PKC, and TRPV4 channels in PAs, promoting their spatial proximity and enabling signaling interactions. These results indicate that endothelial Panx1-P2Y2R-TRPV4 channel signaling, facilitated by caveolin-1, reduces PA contractility and lowers PAP.

biochemistry↗

bioRxiv2018

TLR3 deficiency exacerbates the loss of epithelial barrier function during genital tract Chlamydia muridarum infection

ProblemChlamydia trachomatis infections are often associated with acute syndromes including cervicitis, urethritis, and endometritis, which can lead to chronic sequalae such as pelvic inflammatory disease (PID), chronic pelvic pain, ectopic pregnancy, and tubal infertility. As epithelial cells are the major cell type productively infected during genital tract Chlamydia infections, we investigated whether Chlamydia has any impact on the integrity of the host epithelial barrier as a possible mechanism to facilitate the dissemination of infection, and examined whether TLR3 function modulates its impact.\n\nMethod of StudyWe used wild-type and TLR3-deficient murine oviduct epithelial (OE) cells to ascertain whether C. muridarum infection had any effect on the epithelial barrier integrity of these cells as measured by transepithelial resistance (TER) and cell permeability assays. We next assessed whether infection impacted the transcription and protein function of the cellular tight-junction (TJ) genes for claudins1-4, ZO-1, JAM1 and occludin via quantitative real-time PCR (qPCR) and western blot.\n\nResultsqPCR, immunoblotting, transwell permeability assays, and TER studies show that Chlamydia compromises cellular TJ function throughout the course of infection in murine OE cells, and that TLR3 deficiency significantly exacerbates this effect.\n\nConclusionOur data show that TLR3 plays a role in modulating epithelial barrier function during Chlamydia infection of epithelial cells lining the genital tract. This proposes a role for TLR3 signaling in maintaining the integrity of epithelial barrier function during genital tract Chlamydia infection, a function that we hypothesize is important in helping limit the chlamydial spread and subsequent genital tract pathology.

immunology↗