[Effects and mechanisms of total flavones of Abelmoschus manihot combined with empagliflozin in attenuating diabetic tubulopathy through multiple targets based on mitochondrial homeostasis and ZBP1-mediated PANoptosis].

Abstract

This study aimed to explore the mechanisms and molecular targets of total flavones of Abelmoschus manihot(TFA) plus empagliflozin(EM) in attenuating diabetic tubulopathy(DT) by targeting mitochondrial homeostasis and pyroptosis-apoptosis-necroptosis(PANoptosis). In the in vivo study, the authors established the DT rat models through a combination of uninephrectomy, administration of streptozotocin via intraperitoneal injections, and exposure to a high-fat diet. Following modeling successfully, the DT rat models received either TFA, EM, TFA+EM, or saline(as a vehicle) by gavage for eight weeks, respectively. In the in vitro study, the authors subjected the NRK52E cells with or without knock-down Z-DNA binding protein 1(ZBP1) to a high-glucose(HG) environment and various treatments including TFA, EM, and TFA+EM. In the in vivo and in vitro studies, The authors investigated the relative characteristics of renal tubular injury and renal tubular epithelial cells damage induced by reactive oxygen species(ROS), analyzed the relative characteristics of renal tubular PANoptosis and ZBP1-mediatted PANoptosis in renal tubular epithelial cells, and compared the relative characteristics of the protein expression levels of marked molecules of mitochondrial fission in the kidneys and mitochondrial homeostasis in renal tubular epithelial cells, respectively. Furthermore, in the network pharmacology study, the authors predicted and screened targets of TFA and EM using HERB and SwissTargetPrediction databases; The screened chemical constituents and targets of TFA and EM were constructed the relative network using Cytoscape 3.7.2 network graphics software; The relative targets of DT were integrated using OMIM and GeneCards databases; The intersecting targets of TFA, EM, and DT were enriched and analyzed signaling pathways by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG) software using DAVID database. In vivo study results showed that TFA+EM could improve renal tubular injury, the protein expression levels and characteristics of key signaling molecules in PANoptosis pathway in the kidneys, and the protein expression levels of marked molecules of mitochondrial fission in the kidneys. And that, the ameliorative effects in vivo of TFA+EM were both superior to TFA or EM. Network pharmacology study results showed that TFA+EM treated DT by regulating the PANoptosis signaling pathway. In vitro study results showed that TFA+EM could improve ROS-induced cell injury, ZBP1-mediatted PANoptosis, and mitochondrial homeostasis in renal tubular epithelial cells under a state of HG, including the protein expression levels of marked molecules of mitochondrial fission, mitochondrial ultrastructure, and membrane potential level. And that, the ameliorative effects in vitro of TFA+EM were both superior to TFA or EM. More importantly, using the NRK52E cells with knock-down ZBP1, the authors found that, indeed, ZBP1 was mediated PANoptosis in renal tubular epithelial cells as an upstream factor. In addition, TFA+EM could regulate the protein expression levels of marked signaling molecules of PANoptosis by targeting ZBP1. In summary, this study clarified that TFA+EM, different from TFA or EM, could attenuate DT with multiple targets by ameliorating mitochondrial homeostasis and inhibiting ZBP1-mediated PANoptosis. These findings provide the clear pharmacological evidence for the clinical treatment of DT with a novel strategy of TFA+EM, which is named "coordinated traditional Chinese and western medicine".