Rapamycin inhibits LOC102553434-mediated pyroptosis to improve lung injury induced by limb ischemia–reperfusion

Abstract

Limb ischemia reperfusion (I/R) triggers local or systemic injury, and whether the process is mediated by pyroptosis remains unclear, we aimed to explore whether pyroptosis was involved in the process of rapamycin alleviating lung injury induced by I/R and investigate the molecular mechanisms. The histopathology of lung injury induced by I/R was confirmed by hematoxylin–eosin (HE) staining, and malondialdehyde (MDA), superoxide dismutase (SOD), and the expression of pyroptosis related molecules were detected. RNA sequencing was used to mine key long non-coding RNAs (lncRNAs). The model of lipopolysaccharide (LPS)-induced L2 cell damage was also used to explore the effect and mechanism of rapamycin on lncRNA. Rapamycin treatment alleviated I/R—induced lung histopathologically injury and increased the concentration of MDA while decreased activity of SOD and expression of NLRP3, Caspase-1, interleukin-1β (IL-1β), and IL-18 in rat. A total of 63 differentially expressed lncRNAs (DElncRNAs) were identified from IR + Rap group compared with IR group, and these DElncRNAs were mainly involved in cell adhesion molecules (CAMs) and endocytosis pathway. The lncRNA LOC102553434 and its target gene MMP9 were most significantly up-regulated in I/R-injured rat. In vitro experiments showed that LPS induction caused a significant increase in LOC102553434, MMP9, IL-1β, and IL-18 in L2 cells, but rapamycin treatment significantly reversed the effects. After interfering with the expression of LOC102553434 in the LPS-injured cells pretreated with rapamycin, cell proliferation significantly increased, and the expression of MMP, NLRP3 and caspase-1 were significantly decreased. Rapamycin protects the lung from limb I/R injury by regulating LOC102553434 expression and inhibiting pyroptosis pathway. LOC102553434 plays a role in promoting pyroptosis and thus provides a target for clinical treatment of I/R-induced lung injury.