Acid-sensitive ion channel 1a regulates TNF-? expression in LPS-induced acute lung injury via ERS-CHOP-C/EBP? signaling pathway

Background: Acute lung injury (ALI) is the local inflammatory response of the lungs involved in a variety of inflammatory cells. Macrophages are immune cells and inflammatory cells widely distributed in the body. Acid -sensitive ion channel 1a (ASIC1a) is involved in the occurrence of ALI, but the mechanism is still unclear.Methods: Kunming mouse were stimulated by Lipopolysaccharides (LPS) to establish ALI model in vivo, and RAW264.7 cells were stimulated by LPS to establish inflammatory model in vitro. Amiloride was used as a blocker of ASIC1a to treat mice, and dexamethasone was used as a positive drug for ALI. After blockers and RNAi blocked or silenced the expression of ASIC1a, the expressions of ASIC1a, endoplasmic reticulum-related proteins GRP78, CHOP, C/EBP alpha and TNF-alpha were detected. The Ca2+ concentration was measured by a laser confocal microscope. The interaction between CHOP and C/EBP alpha and the effect of C/EBP alpha on the activity of TNF-alpha promoter were detected by immunoprecipitation and luciferase reporter.Results: The expressions of ASIC1a and TNF-alpha were increased significantly in LPS group. After the blocker and RNAi blocked or silenced ASIC1a, the expressions of TNF-alpha, GRP78, CHOP were reduced, and the intracellular Ca2+ influx was weakened. The results of immunoprecipitation showed that CHOP and C/EBP alpha interacted in the macrophages. After silencing CHOP, C/EBP alpha expression was increased, and TNF-alpha expression was decreased. The results of the luciferase reporter indicated that C/EBP alpha directly binds to TNF-alpha.Conclusion: ASIC1a regulates the expression of TNF-alpha in LPS-induced acute lung injury via ERS-CHOP-C/EBP alpha signaling pathway.

Automated summary

This study found that ASIC1a regulates TNF-alpha expression in LPS-induced ALI through the ERS-CHOP-C/EBP alpha signaling pathway. The results showed that blocking or silencing ASIC1a can reduce the expression of TNF-alpha, GRP78, and CHOP, and weaken intracellular Ca2+ influx. Immunoprecipitation results indicated that CHOP and C/EBP alpha interact in macrophages. Silencing CHOP increased C/EBP alpha expression and decreased TNF-alpha expression. Luciferase reporter results indicated that C/EBP alpha directly binds to TNF-alpha.