Vibrio vulnificus VvhA induces autophagy-related cell death through the lipid raft-dependent c-Src/NOX signaling pathway

Abstract

VvhA, a virulent factor of Vibrio (V.) vulnificus, induces acute cell death in a destructive manner. Autophagy plays an important role in cell death, but the functional role of VvhA in autophagy-related cell death has not been elucidated yet. We found that rVvhA significantly increased LC3 puncta formation and autophagic flux in promoting the cell death of human intestinal epithelial Caco-2 cells. The cell death induced by rVvhA was independent of lysosomal permeabilizaton and caspase activation. rVvhA induced rapid phosphorylation of c-Src in the membrane lipid raft, which resulted in an increased interaction between lipid raft molecule caveolin-1 and NADPH oxidase (NOX) complex Rac1 for ROS production. NOX-mediated ROS signaling induced by rVvhA increased the phosphorylation of extracellular signal-regulated kinase (ERK) and eukaryotic translation initiation factor 2α (eIF2α) which are required for mRNA expression of Atg5 and Atg16L1 involved in autophagosome formation. In an in vivo model, VvhA increased autophagy activation and paracellular permeabilization in intestinal epithelium. Collectively, the results here show that VvhA plays a pivotal role in the pathogenesis and dissemination of V. vulnificus by autophagy upregulation, through the lipid raft-mediated c-Src/NOX signaling pathway and ERK/eIF2α activation.

High Glucose-Induced Reactive Oxygen Species Stimulates Human Mesenchymal Stem Cell Migration Through Snail and EZH2-Dependent E-Cadherin Repression

“…Intracellular ROS detection was described in previous reports [39]. ROS was detected by using DCF-DA, which is a fluorescence-based probe for ROS detection.…”

Nanosphere Loaded With Curcumin Inhibits the Gastrointestinal Cell Death Signaling Pathway Induced by the Foodborne Pathogen Vibrio vulnificus

“…Vibrio (V.) vulnificus is a pathogenic marine bacterium associated with foodborne illnesses, often causing gastroenteritis, septicemia, and diarrhea [1]. Infection with V. vulnificus is cytotoxic to host cells, and its virulence is mediated by secreted cytotoxins and enzymes, such as VvhA, MARTX, VvpE, and VvpM [1][2][3][4][5][6]. VvhA is one of the most potent pore-forming cytotoxins capable of killing mice at sub-µg levels, and it plays a crucial role in the pathogenesis and dissemination of V. vulnificus by facilitating intestinal paracellular permeabilization [2].…”

“…Infection with V. vulnificus is cytotoxic to host cells, and its virulence is mediated by secreted cytotoxins and enzymes, such as VvhA, MARTX, VvpE, and VvpM [1][2][3][4][5][6]. VvhA is one of the most potent pore-forming cytotoxins capable of killing mice at sub-µg levels, and it plays a crucial role in the pathogenesis and dissemination of V. vulnificus by facilitating intestinal paracellular permeabilization [2]. Recent studies have suggested that recombinant (r) VvhA stimulates the mitochondrial apoptotic machinery through the production of intracellular reactive oxygen species (ROS) derived from NADPH oxidase 2 (NOX2) located on membrane lipid rafts, thereby governing the PKC, MAPK, and NF-κB signaling pathways during the infection of host cells [7].…”

Correlation of Total Bacterial and Vibrio spp. Populations between Fish and Water in the Aquaculture System

“…V. parahaemolyticus O1:Kuk strain may potentially cause human illness, because this strain is closely related with strain O3:K6 which was associated with quite a number of Asian outbreaks (Depaola et al, 2003). V. vulnificus MLT1009 has VvhA (virulent factor of V. vulnificus) gene that induces autophagy-related cell death (Song et al, 2016). Each was cultivated overnight in Tryptic Soy Broth, (TSB, Carolina Biological Supply Co.) supplemented with 2% additional NaCl at 37 • C, and washed twice with normal saline (0.85% NaCl) buffer.…”