title: P2X7 receptors mediate NADH transport across the plasma membranes of astrocytes.
abstract: NADH plays critical roles in mitochondrial functions and energy metabolism. There has been no study demonstrating that NADH can be transported across the plasma membranes of cells. In this study we tested our hypothesis that NADH can be transported across the plasma membranes of astrocytes by a P2X7 receptor (P2X7R)-mediated mechanism. We found that treatment of astrocytes with NADH led to increases in both intracellular NADH and NAD+. Three lines of studies suggest that P2X7R mediates the NADH transport into astrocytes: the P2X receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) blocked the NADH transport; RNAi knockdown of P2X7R led to decreased NADH transport; and transfection of HEK293 cells with mouse P2X7R cDNA led to increased NADH transport. Collectively, our study provides the first direct evidence demonstrating that NADH can be transported across the plasma membranes of astrocytes by a P2X7R-mediated mechanism. Our study also suggests a novel approach for manipulating intracellular NADH and NAD+ levels.
authors.affiliation: Department of Neurology, Veterans Affairs Medical Center and the University of California at San Francisco, 4150 Clement Street, San Francisco, CA 94121, USA.
authors.forename: Huafei
authors.initials: H
authors.lastname: Lu
authors.forename: David
authors.initials: D
authors.lastname: Burns
authors.forename: Philippe
authors.initials: P
authors.lastname: Garnier
authors.forename: Guangwei
authors.initials: G
authors.lastname: Wei
authors.forename: Keqing
authors.initials: K
authors.lastname: Zhu
authors.forename: Weihai
authors.initials: W
authors.lastname: Ying
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001693:Biological Transport, Active / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D051379:Mice; D009243:NAD / Q000493:pharmacokinetics*; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7