P2X7 receptor blockade reduces pyroptotic inflammation and promotes
phagocytosis in Vibrio vulnificus infection
Abstract
Background and Purpose Vibrio vulnificus (V. vulnificus),
a gram-negative bacterium, causes serious wound infections and
septicemia. Once it develops into early-phase sepsis, hyperinflammatory
immune responses result in poor prognosis in patients. The present study
aimed to examine the possible underlying pathogenic mechanism and
explore potential agents that could protect against V.
vulnificus cytotoxicity. Experimental Approach The anti-pyroptotic
effects of P2X7 receptor (P2X7R) antagonists were assessed in an
experimental murine V vulnificus infection. In vitro, the effects
of P2X7R antagonists on V vulnificus-induced anti-phagocytosis
and pyroptosis in murine macrophages were examined. Key Results Here, we
report that infection of mouse macrophages with V. vulnificus
triggers anti-phagocytic effects and pyroptotic inflammation via
ATP-mediated purinergic P2X7R signaling. V. vulnificus promoted
P2X7-dependent NF-κB p65 translocation, modulating the expression of the
inflammasome sensor NLRP3, adaptor ASC, and pyroptotic protein gasdermin
D (GSDMD) in mouse macrophages. V. vulnificus induced the
NLRP3/caspase-1 inflammasome signaling complex expression that drives
GSDMD transmembrane pore formation and secretion of IL-1β, IL-18, and
MIP-2. This effect was blocked by P2X7R antagonists, indicating that the
P2X7R mediates GSDMD-related pyroptotic inflammation in macrophages
through the NF-κB/NLRP3/caspase-1 signaling pathway. Furthermore,
blockade of P2X7R reduced V. vulnificus-colony-forming units in
the spleen, immune cell infiltration into the skin and lung tissues, and
serum concentrations of IL-1β, IL-18, and MIP-2 in mice. Conclusions and
Implications These results indicate that P2X7R plays a vital role in
mediating phagocytosis by macrophages and pyroptotic inflammation during
V. vulnificus infection and provides new opportunities for
therapeutic intervention in bacterial infections.