Desmoglein-3 acts as a pro-survival protein by suppressing reactive oxygen species and doming whilst augmenting the tight junctions in MDCK cells

Xiao Li,Usama Sharif Ahmad,Yunying Huang,Jutamas Uttagomol,Ambreen Rehman,Ke Zhou,Gary Warnes,Simon Mcarthur,Eric Kenneth Parkinson,H Wan

doi:10.1016/j.mad.2019.111174

Abstract

Kidney disease prevalence increases with age, with a common feature of the disease being defects in the epithelial tight junctions. Emerging evidence suggests that the desmosomal adhesion protein Desmoglein-3 (Dsg3) functions beyond the desmosomal adhesion and plays a role in regulating the fundamental pathways that govern cell fate decisions in response to environmental chemical and mechanical stresses. In this study, we explored the role of Dsg3 on dome formation, reactive oxygen species (ROS) production and transepithelial electrical resistance (TER) in MDCK cells, a kidney epithelial cell model widely used to study cell differentiation and tight junction formation and integrity. We show that overexpression of Dsg3 constrained nuclear ROS production and cellular doming in confluent cell cultures and these features coincided with augmented TER and enhanced tight junction integrity. Conversely, cells expressing dominant-negative Dsg3ΔC mutants exhibited heightened ROS production and accelerated doming, accompanied by increased apoptosis, as well as cell proliferation, with massive disruption in F-actin organization and accumulation, and alterations in tight junctions. Inhibition of actin polymerization and protein synthesis was able to sufficiently block dome formation in mutant populations. Taken together, these findings underscore that Dsg3 has a role in controlling cellular viability and differentiation as well as the functional integrity of tight junctions in MDCK cells.

Highlights

The prevalence of end-stage renal disease increases almost exponentially in parallel with chronological age (Stewart et al, 2006)
We provide the first evidence that the desmosomal cadherin Dsg3 acts as a prosurvival protein, playing a role in maintaining cellular longevity by suppressing reactive oxygen species (ROS) production, apoptosis and cell differentiation as indicated by the inhibition of domes in Madin-Darby Canine Kidney (MDCK) cells
This conclusion is further supported by the observed phenotype of Dsg3∆C mutant cells that exhibit premature doming, elevated ROS levels, and apoptosis with defects in tight junction (TJ) and the actin cytoskeleton

Summary

Introduction

The prevalence of end-stage renal disease increases almost exponentially in parallel with chronological age (Stewart et al, 2006). It has been reported that domes can be induced by compounds such as hexamethylene bis acetamide (HMBA) and dimethylformamide (DMF) that are known to induce cell differentiation (Kennedy and Lever, 1984,Leighton et al, 1970,Oberleithner et al, 1990), and dome formation is regarded as a feature of ageing or differentiation Ion transporters such as Na+/K+-ATPase and cAMP which are involved in regulating epithelial transmembrane transport, and Stat signaling that induces NHE3 expression, are independently implicated in promoting dome formation in MDCK cell lines (Su et al, 2007,Sugahara et al, 1984,Lever, 1979b,Lever, 1979a). While the former exhibits the “tight” junction phenotype with high TER values (>1000 Ω·cm2), the latter, i.e. MDCK II cell line possesses a ‘leaky’ phenotype with much lower TER values (

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Conclusion