Metformin enhances ATP-stimulated inflammasomeactivation in LPS-primed peritoneal macrophages / 中国药理学通报

ABSTRACT

Aim To explore the influence of metformin(a first-line drug for type 2 diabetes) on ATP-induced inflammasome activation and the release of interleukin-1β(IL-1β) by LPS-activated peritoneal macrophages, a commonly-used inflammatory cell model.Methods Peritoneal macrophages were elicited by intraperitoneal injection of 30 g·L-1 thioglycollate into C57BL/6 mice.Inflammasome was activated and cell pyroptosis was induced by LPS plus ATP treatment, and the pyroptotic cells were calculated after propidium iodide(PI) staining.The protein levels of IL-1β and caspase-1 expressed in the cells and released from them into the supernatant were evaluated by Western blot.Immunofluorescent microscopy was recruited to detect the subcellular distribution and fluorescent intensity of the purinergic P2X7 receptor(P2X7R).Results Metformin per se did not induce pyroptosis in LPS-activated peritoneal macrophages, but it significantly and dose-dependently increased cell pyroptosis induced by ATP treatment.At protein levels, maturated IL-1β(17 ku) could not be released from the cells upon single LPS or LPS plus metformin stimulation;but after ATP was added, maturated IL-1β was released into the supernatants of the cells.Moreover, metformin dose-dependently increased the protein levels of both maturated IL-1β and active caspase-1 released by the LPS-activated peritoneal macrophages upon ATP stimulation.Conclusion Metformin intensifies the activation of inflammasome and increases the release of active caspase-1 and maturated IL-1β upon ATP stimulation in the LPS-activated peritoneal macrophages, which should promote inflammatory responses.