ODC1 loss upon KLF6 upregulation promotes macrophage pyroptosis and acute kidney injury in sepsis

The excessive inflammatory cascade in sepsis represents a major cause of multiorgan injuries, including sepsis-associated acute kidney injury (SAKI). Following the bioinformatics prediction, this study aims to investigate the role of ornithine decarboxylase 1 (ODC1) in macrophage phenotype in SAKI. C57BL/6 J mice and mouse bone marrow-derived macrophages or THP-1 cells were subjected to lipopolysaccharide (LPS) treatments to generate septic models. RT-qPCR and western blot assays revealed a reduced expression pattern of ODC1 in the kidney of mice and the BMDMs following LPS challenges. Upregulation of ODC1 ameliorated kidney injury, reduced M1 polarization of macrophages, and alleviated inflammatory cytokine secretion. Moreover, this upregulation inactivated the nuclear factor-kappa B signaling and enhanced macrophage Autophagy while reducing Pyroptosis. KLF6, highly expressed in septic mice, was found to repress ODC1 transcription by binding to its promoter. Silencing of KLF6 similarly promoted macrophage Autophagy and inhibited Pyroptosis, ameliorating kidney injury and inflammation in mice. These effects were, however, negated by the additional ODC1 silencing. Collectively, this study suggests that KLF6-mediated ODC1 loss inhibits macrophage Autophagy while promoting Pyroptosis, thus resulting in inflammation and progression of SAKI.

Autophagy; KLF6; Macrophages; ODC1; Pyroptosis; Sepsis-associated acute kidney injury.