Agmatine protects mitochondria in LPS-stimulated microglia

Abstract

Mitochondria play a key role in energy metabolism and regulate some of the principal cellular processes such as the production of ATP and reactive oxygen species, as well as a regulation of apoptotic cell death. Mitochondrial dysfunction and oxidative stress are common threads in most neurodegenerative disorders, which are also accompanied by chronic microglial activation. Agmatine, neuromodulatory polyamine, was shown to exhibit neuroprotective effects in oxidative stress conditions. Therefore, the goal of this study was to determine the ability of agmatine to preserve mitochondrial function and prevent apoptosis during neuroinflammation. The effects of 100 µM agmatine on cellular energy status and cell death were examined in LPS-stimulated BV2 microglial cell line. To detect changes in mitochondrial membrane potential, TMRE fluorescent assay was performed, while the changes in intracellular ATP concentration were determined by bioluminescent assay, 6h, and 24h after LPS stimulation. The expression of apoptosis regulators Bax and Bcl2 was assessed by Western blot analysis and the Bax/Bcl2 ratio was determined. Agmatine increases mitochondrial membrane potential, indicating its protective role during mitochondrial insult caused by LPS stimulation. LPS and agmatine administrated separately, increase intracellular ATP levels, however, agmatine treatment followed by LPS stimulation enhances ATP production even further, at both time points. Moreover, agmatine shows an antiapoptotic effect by reduction of Bax/Bcl2 ratio in comparison to LPS stimulation. We conclude that the results of this study indicate the capacity of agmatine to protect mitochondrial function and suppress apoptosis, which may be beneficial in neurodegenerative disorders and neuroinflammation.