Polycystin-2 Plays an Essential Role in Glucose Starvation-Induced Autophagy in Human Embryonic Stem Cell-Derived Cardiomyocytes

Abstract

Autophagy is a process essential for cell survival under stress condition. The patients with autosomal dominant polycystic kidney disease, which is caused by polycystin-1 or polycystin-2 (PKD2) mutation, display cardiovascular abnormalities and dysregulation in autophagy. However, it is unclear whether PKD2 plays a role in autophagy. In the present study, we explored the functional role of PKD2 in autophagy and apoptosis in human embryonic stem cell-derived cardiomyocytes. HES2 hESC line-derived cardiomyocytes (HES2-CMs) were transduced with adenoviral-based PKD2-shRNAs (Ad-PKD2-shRNAs), and then cultured with normal or glucose-free medium for 3 hours. Autophagy was upregulated in HES2-CMs under glucose starvation, as indicated by increased microtubule-associated protein 1 light chain 3-II level in immunoblots and increased autophagosome and autolysosome formation. Knockdown of PKD2 reduced the autophagic flux and increased apoptosis under glucose starvation. In Ca measurement, Ad-PKD2-shRNAs reduced caffeine-induced cytosolic Ca rise. Co-immunoprecipitation and in situ proximity ligation assay demonstrated an increased physical interaction of PKD2 with ryanodine receptor 2 (RyR2) under glucose starvation condition. Furthermore, Ad-PKD2-shRNAs substantially attenuated the starvation-induced activation of AMP-activated protein kinase (AMPK) and inactivation of mammalian target of rapamycin (mTOR). The present study for the first time demonstrates that PKD2 functions to promote autophagy under glucose starvation, thereby protects cardiomyocytes from apoptotic cell death. The mechanism may involve PKD2 interaction with RyR2 to alter Ca release from sarcoplasmic reticulum, consequently modulating the activity of AMPK and mTOR, resulting in alteration of autophagy and apoptosis. Stem Cells 2018;36:501-513.

Effect of Trehalose Supplementation on Autophagy and Cystogenesis in a Mouse Model of Polycystic Kidney Disease

“…Autophagy impairment has been proposed to play a crucial role in the pathogenesis of ADPKD by modulating cell proliferation [42]. A defect in autophagy may predispose cyst lining cells to apoptosis and promote cyst formation in ADPKD [43]. However, the degree of autophagy impairment in different stages of cyst development, such as early versus late, could be different [13].…”

TMEM33 regulates intracellular calcium homeostasis in renal tubular epithelial cells

“…Recent studies indicate that PC2 stimulates autophagy in a variety of cell types, including renal epithelial cells, as well as cardiomyocytes, involving both the primary cilium and intracellular calcium stores 28–31 . LC3 is the most widely used autophagosome marker because the amount of LC3 II (conjugated to phosphatidylethanolamine) reflects the number of autophagosomes 32 .…”

Endoplasmic reticulum stress is involved in lipopolysaccharide‐induced inflammatory response and apoptosis in goat endometrial stromal cells

“…Previous studies have shown that there is evidence for the link between ER stress and the inflammatory cytokine activation that IL‐1β decreased significantly when pretreated human cells were treated with 4‐PBA or TUDCA under LPS treatment (Liong & Lappas, ). Previous studies reported that activated autophagy in the cell can lead to several responses, such as a covered self‐degradative catabolic process to degrade and recycle damaged organelles, and that activated autophagy coordinates programmed cell death but also has a protective role against apoptosis under stress conditions (Lu et al, ; Wang et al, ). LC3 plays a critical role in autophagosomes and is a marker of autophagy activation (Tanida, Ueno & Kominami, ).…”