This study highlights a novel approach to upregulate mitochondrial biogenesis in neuronal cells. RNS60 is a 0.9% saline solution containing oxygenated nanobubbles that is generated by subjecting normal saline to Taylor-Couette-Poiseuille (TCP) flow under elevated oxygen pressure. RNS60, but not NS (normal saline), PNS60 (saline containing a comparable level of oxygen without the TCP modification), or RNS10.3 (TCP-modified normal saline without excess oxygen), increased the expression of Nrf1, Tfam, Mcu, and Tom20 (genes associated with mitochondrial biogenesis) and upregulated mitochondrial biogenesis in MN9D dopaminergic neuronal cells. Similarly RNS60 also increased mitochondrial biogenesis in primary dopaminergic neurons and in the nigra of MPTP-intoxicated mice. However, RNS60 had no effect on lysosomal biogenesis. Interestingly, we found that RNS60 upregulated PGC1α and siRNA knockdown of PGC1α abrogated the ability of RNS60 to increase mitochondrial biogenesis. Furthermore, we delineated that RNS60 increased the transcription of Pgc1a via type IA phosphatidylinositol (PI) 3-kinase-mediated activation of cAMP-response element-binding protein (CREB). Accordingly, knockdown of the PI3K - CREB pathway suppressed RNS60-mediated mitochondrial biogenesis. These results describe a novel property of RNS60 of enhancing mitochondrial biogenesis via PI 3-kinase-CREB-mediated up-regulation of PGC1α, which may be of therapeutic benefit in different neurodegenerative disorders.
Keywords: Mitochondrial biogenesis; Modified saline; Nanobubbles; Neurons; PGC1α; PI3 kinase.