Vibrio vulnificus VvpE Stimulates IL-1β Production by the Hypomethylation of the IL-1β Promoter and NF-κB Activation via Lipid Raft–Dependent ANXA2 Recruitment and Reactive Oxygen Species Signaling in Intestinal Epithelial Cells

Abstract

An inflammatory response is a hallmark of necrosis evoked by bacterial pathogens. Vibrio vulnificus, VvpE, is an elastase that is responsible for tissue necrosis and inflammation; however, the molecular mechanism by which it regulates host cell death has not been characterized. In the present study, we investigate the cellular mechanism of VvpE with regard to host cell death and the inflammatory response of human intestinal epithelial (INT-407) cells. The recombinant protein (r)VvpE (50 pg/ml) caused cytotoxicity mainly via necrosis coupled with IL-1β production. The necrotic cell death induced by rVvpE is highly susceptible to the knockdown of annexin A (ANXA)2 and the sequestration of membrane cholesterol. We found that rVvpE induces the recruitment of NADPH oxidase 2 and neutrophil cytosolic factor 1 into membrane lipid rafts coupled with ANXA2 to facilitate the production of reactive oxygen species (ROS). The bacterial signaling of rVvpE through ROS production is uniquely mediated by the phosphorylation of redox-sensitive transcription factor NF-κB. The silencing of NF-κB inhibited IL-1β production during necrosis. rVvpE induced hypomethylation and region-specific transcriptional occupancy by NF-κB in the IL-1β promoter and has the ability to induce pyroptosis via NOD-, LRR-, and pyrin domain–containing 3 inflammasome. In a mouse model of V. vulnificus infection, the mutation of the vvpE gene from V. vulnificus negated the proinflammatory responses and maintained the physiological levels of the proliferation and migration of enterocytes. These results demonstrate that VvpE induces the hypomethylation of the IL-1β promoter and the transcriptional regulation of NF-κB through lipid raft–dependent ANXA2 recruitment and ROS signaling to promote IL-1β production in intestinal epithelial cells.

Study of the Antimicrobial Activity of Tilapia Piscidin 3 (TP3) and TP4 and Their Effects on Immune Functions in Hybrid Tilapia (Oreochromis spp.)

“…The V . vulnificus VvpE stimulates IL-1β production via hypomethylation of the IL-1β promoter and NF-κB activation in the intestinal epithelial cells [35], but whether TP3 or TP4 are involved in IL-1β promoter and NF-κB activation in tilapia after V . vulnificus infection requires further investigation.…”

Vibrio vulnificus induces mTOR activation and inflammatory responses in macrophages

“…Extensive work has linked various virulence factors of V . vulnificus to cell death and modulation of innate immune responses to this pathogen [30, 33–37]. Patients with liver diseases such as cirrhosis are more susceptible to developing V .…”

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].…”