The Effect of Viral RNA-Mimetics on Microglia Cell Cultures and Mitochondrial Network Formation

The main causes of development of neurodegenerative diseases, such as Parkinson‘s and Alzheimer‘s are neuronal damage and loss, often associated with neuroinflammatory processes. Neuroinflammation can be caused by various factors, including bacterial and viral infections, leading to activation of cells of the brain immune system, including microglial cells, which play a crucial role in the development of neurodegenerative diseases and can have a negative effect on neurons. Viral components can activate microglial cells via pattern recognition receptors, such as TLR3 and TLR7, modulating inflammatory processes. Some research papers suggest that changes in mitochondrial metabolism and dynamics can modulate neuroinflammatory responses in microglia, however, this is under investigated and poorly understood. In this study, using various methods including fluorescence microscopy, BrdU assay, polymerase chain reaction (PCR), we investigated effects of viral RNA-mimetics Loxoribine and Poly (I:C) on microglial BV-2 cells and mitochondrial dynamics. We found that Loxoribine and Poly (I:C) significantly increased expression of mitochondrial fission factor (Mff) fission marker compared to the control group but had no effect on expression of fusion marker mitofusin 1 (Mfn1) in BV-2 cell cultures. Loxoribine and Poly (I:C) had no effect on microglial viability, proliferation or mitochondrial content. Our results suggest that viral RNA-mimetics may affect structures of mitochondrial networks in microglial cells through increased expression of fission proteins.