BMAL1 alleviates sepsis-induced acute kidney injury by inhibiting apoptosis, ferroptosis and inflammation.

Background: Sepsis is a life-threatening syndrome characterized by organ dysfunction. The kidney is one of the earliest organs to be injured during sepsis. Basic Helix-Loop-Helix ARNT Like 1 (BMAL1) was shown to play a critical role in immune responses. BMAL1 deregulation is related to sepsis-induced injury. Thus, correct understanding of the molecular mechanism of BMAL1 in sepsis-induced acute kidney injury (AKI) may be importance for seeking effective targeted therapy.

Methods: Lipopolysaccharide (LPS)-induced renal tubular epithelial cells (HK-2 cells) and a sepsis-AKI model established in C57BL/6 mice using cecal ligation and puncture (CLP) were used for functional analyses. In vitro analyses were conducted using EdU assay, flow cytometry, MTT assay and ELISA, respectively. Levels of mRNA and protein expression were using qRT-PCR and western blotting. Cellular ubiquitination analyzed the ubiquitination effect of USP10 on BMAL1. The binding of HOXA5 to BMAL1 promoter was verified using Chromatin immunoprecipitation and Luciferase reporter assays.

Results: BMAL1 overexpression reversed LPS-induced apoptosis, inflammation and ferroptosis in HK-2 cells, as well as attenuated sepsis-induced AKI in mouse models. Mechanistically, USP10 bound to BMAL1 and positively modulated BMAL1 expression by reducing BMAL1 ubiquitination. In addition, HOXA5 induced BMAL1 transcription. Moreover, USP10 or HOXA5 overexpression reversed LPS-induced apoptosis, inflammation and ferroptosis in HK-2 cells, which could be rescued by BMAL1 decrease.

Conclusion: BMAL1 overexpression mediated by USP10-induced deubiquitination or HOXA5-induced transcription can attenuate sepsis-induced acute kidney injury, recommending a novel insight for the prevention of sepsis-induced AKI.