TFAM-Associated Mitochondrial Dynamics and Metabolic Reprogramming Regulate Microglial Polarization: Temporal and Causal Perspectives

The polarization state of microglia exerts an influence on neuroinflammation and neural tissue repair after injury. Modulating microglial polarization is emerging as a potential therapeutic strategy for various types of neural injuries and neurodegenerative diseases. However, the causal relationship between microglial polarization and mitochondrial dynamics, which include mitochondrial fusion and fission, remains to be fully clarified. Our study demonstrates that mitochondrial fusion promoter M1 promotes mitochondrial fusion in mouse microglial cells, leading to reduced glycolysis and increased fatty acid oxidation, and this metabolic reprogramming impacts microglial polarization. Additionally, in both cellular and animal experiments, it was observed that knocking down mitochondrial transcription factor A (TFAM) results in increased mitochondrial fission, decreased fatty acid β-oxidation, enhanced glycolysis, and promotes the polarization of microglia toward the pro-inflammatory M1 phenotype. In conclusion, our study has, for the first time, provided evidence that TFAM may play a role in the regulation of mitochondrial dynamics. Furthermore, we provide a detailed elucidation of the chronological sequence and underlying causal relationships among mitochondrial dynamics, mitochondrial metabolic reprogramming, and microglial polarization. These findings offer novel targets and strategies for the treatment of various neural injuries and neurodegenerative diseases. Graphical The balance between mitochondrial fusion and fission meets the energy demands of resting BV2 microglia. TFAM promotes mitochondrial fusion, which suppresses glycolysis and enhances fatty acid β-oxidation in BV2 cells, and thereby drives resting microglia towards the M2 phenotype.