Autophagy gene ATG5 knockdown upregulates apoptotic cell death during Candida albicans infection in human vaginal epithelial cells

Abstract

Problem Candida albicans infection induces damage in host cells that results in the activation of cell death pathways such as apoptosis and necrosis. Autophagy acts as a pro‐survival mechanism during various infections and has cross talks with apoptosis. The objective of our study was to delineate the effect of autophagy knockdown in human vaginal epithelial cells (VECs) during Candida infection‐induced apoptosis. Method of study We overexpressed wild‐type or mutant form of autophagy‐related gene 5 (ATG5) in human VECs and determined the levels of autophagy and lysosome marker genes upon C. albicans infection. We analyzed the expression of apoptosis and necrosis markers using confocal microscopy and flow cytometry. Results Mutant ATG5 overexpressing VECs were unable to form Atg5‐Atg12 complex, which is required for functional autophagy pathway. Upon Candida albicans infection, wild‐type ATG5 overexpressing cells showed upregulation of autophagy marker genes, ATG5, LC3‐I, LC3‐II, and LAMP‐1. Mutant ATG5 overexpressing cells could not upregulate LC3‐II and LAMP‐1 expression, indicating a defective autophagy pathway. Confocal microscopy and flow cytometry results revealed that wild‐type ATG5 overexpressing VECs showed significantly lower number of apoptotic and necrotic cells as compared to mutant ATG5 overexpressing cells. Conclusion Vaginal epithelial cells with active autophagy were able to survive the damage caused by C. albicans infection, whereas those with defective autophagy succumbed to the infection. This suggests that autophagy plays a critical role in human VECs survival during C. albicans infection.

Membrane protective role of autophagic machinery during infection of epithelial cells by Candida albicans

“…Indeed, only two studies described autophagy activation during the infection of vaginal epithelial cells by C. albicans , an event that improved vaginal cell survival upon infection. 22 , 23 Mucosal epithelial cells are at the frontline of host-microbe interactions and represent initial sentinels and responders to pathogens, thereby contributing to the efficiency of the innate immune response. 24 In the gut, a single layer of epithelial cells confers a physical ( e.g .…”

Overexpression of miR‑30c‑5p reduces cellular cytotoxicity and inhibits the formation of kidney stones through ATG5

“…Previous studies have also demonstrated that ATG5 promoted cell apoptosis by activating caspase-8 (37), and that ATG5 is involved in the apoptosis of human cardiomyocytes (38) and colorectal cancer cells (39). The knockdown of ATG5 upregulates the apoptotic cell death of human vaginal epithelial cells (40); moreover, ATG5 suppresses cellular proliferation and induces the apoptosis of dF-1 cells (41). In addition, the inhibition of ATG5 can decrease oxidative stress-based cytotoxicity in osteosarcoma cells (42).…”

Ethyl Extract of Blaps rynchopetera Fairmaire Ameliorates Experimental Aerobic Vaginitis by Inhibiting Autophagy Activation

“…Autophagy remained low in normal rats, implying that probiotics do not need to upregulate autophagy in vaginal mucosa when confronted with inflammatory response and pathogen invasion in the physiological state. Vaginal epithelial cells (VECs) with active autophagy survived the damage caused by C. albicans invasion, indicating that autophagy plays a critical role in the survival of human VECs during infection [16]. Infection with S. aureus, E. coli, or S. agalactiae can activate autophagy in VECs, is not limited to degradation, but instead "hijacks" autophagy, and accelerates proliferation to induce autophagy-dependent host cell death.…”