Scorpion venom heat-resistant peptide alleviates mitochondrial dynamics imbalance induced by PM 2.5 exposure by downregulating the PGC-1α/SIRT3 signaling pathway

Epidemiological inquiry reveals that neuroinflammation and mitochondrial dysfunction caused by PM exposure are associated with Alzheimer's disease. Nevertheless, the molecular mechanisms of mitochondrial dynamics and neuroinflammation induced by PM exposure remain elusive. In this study, our objective was to explore the impact of PM on mitochondrial dynamics and neuroinflammation, while also examining the reparative potential of scorpion venom heat-resistant synthetic peptide (SVHRSP). Western blot and quantitative reverse transcription polymerase chain reaction (RT-qPCR) were employed to ascertain the protein and gene levels of IL-1β, IL-6, and TNF-α in BV2 cells. The concentration of IL-6 in the supernatant of the BV2 cell culture was measured by enzyme-linked immunosorbent assay. For the assessment of mitochondrial homeostasis, western blot, RT-qPCR, and cellular immunohistochemistry methods were utilized to investigate the protein and gene levels of DRP1 and MFN-2 in HT22 cells. In the context of signal pathway analyses, western blot, RT-qPCR, and immunofluorescence techniques were employed to detect the protein and gene expressions of PGC-1α and SIRT3 in HT22 cells, respectively. Following the transfection with siPGC-1αRNA, downstream proteins of PGC-1α/SIRT3 pathway in HT22 cells were investigated by Western blot and RT-qPCR. The experimental findings demonstrated that exposure to PM exacerbated neuroinflammation, resulting in elevated levels of IL-1β, IL-6, and TNF-α. Furthermore, it perturbed mitochondrial dynamics, as evidenced by increased DRP1 expression and decreased MFN-2 expression. Additionally, dysfunction was observed in the PGC-1α/SIRT3 signal pathway. However, intervention with SVHRSP ameliorated the cellular damage induced by PM exposure. SVHRSP alleviated neuroinflammation and mitochondrial dynamics imbalance induced by PM exposure by downregulating the PGC-1α/SIRT3 signaling pathway.