BMAL1 alleviates myocardial damage in sepsis by activating SIRT1 signaling and promoting mitochondrial autophagy.

BACKGROUND: Brain and muscle arnt-like protein-1 (BMAL1) deficiency is associated with myocardial dysfunction and suppressed sirtuin 1 (SIRT1). However, whether BMAL1 promotes mitophagy via SIRT1 to alleviate myocardial injury in sepsis remains unknown. METHODS: An in vitro myocardial injury model was established using lipopolysaccharide (LPS)-treated H9C2 cells. Knockdown or overexpression of genes was performed using plasmid transfection. Gene and protein expression was assessed by qRT-PCR and Western blot, respectively. Cell proliferation was evaluated using cell counting kit-8, and cellular apoptosis and reactive oxygen species (ROS) levels were analyzed using flow cytometry. An in vivo myocardial injury model of sepsis was established by cecal ligation and puncture in rats. Myocardial function was characterized by analyzing the damage-associated proteins, inflammatory factors, ejection fraction, and fraction shortening. RESULTS: sgBMAL1 significantly decreased BMAL1 levels and remarkably increased the sensitivity of H9C2 cells to LPS stimulation, consequently enhancing LPS-induced apoptosis, inflammation, and ROS levels. These effects were further attenuated by BMAL1 overexpression. BMAL1 knockdown inhibited the expression of SIRT1 and mitophagy-associated proteins. SIRT1 overexpression reversed the enhancement of shBMAL1 on cell proliferation and inflammation. In the rat model of sepsis, BMAL1 overexpression decreased the myocardial injury-associated proteins to recover the myocardial function and suppressed inflammatory activities by promoting mitophagy via SIRT1. CONCLUSION: BMAL1 enhances mitophagy dependent on SIRT1, thereby alleviating myocardial injury in sepsis.

Immunological responses of septic rats to combination therapy with thymosin α1 and vitamin C.

This study investigated the effect of combined thymosin α1 and vitamin C (Tα1 + VitC) on the immunological responses of septic rats. Five groups were designed. The septic model was established by the cecal ligation puncture (CLP) method. The sham group did not undergo CLP, the model group was given normal saline solution, the Tα1 group was given Tα1 (200 µg/kg), the VitC group was given VitC (200 mg/kg), and the Tα1 + VitC group was given Tα1 + VitC. Specimens for immunological analyses were collected at 6, 12, 24, and 48 h posttreatment in each group except for the sham group (only at 48 h). CD4 + CD25 + T cells in the peripheral blood and dendritic cell (DC) proportions in the spleen were analyzed by flow cytometry. Tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), transforming growth factor-ß (TGF-ß1), and nuclear factor kappa-B (NF-κB) were measured by ELISA. CD4 + CD25 + T cells and OX62 + DCs levels significantly increased in the model group and decreased in the Tα1 and/or VitC treatment groups. Similarly, the levels of TNF-α, IL-6, TGF-ß1, and NF-κB significantly increased in the model group and decreased in the Tα1, VitC, and Tα1 + VitC groups, indicating that combined Tα1 and VitC therapy may help regulate the immunological state of patients with sepsis, thereby improving prognosis.