CFTR and sphingolipids mediate hypoxic pulmonary vasoconstriction

Christoph Tabeling, Hanpo Yu, Liming Wang, Hannes Ranke, Neil M. Goldenberg, Diana Zabini, Elena Noe, Adrienn Krauszman, Birgitt Gutbier, Jun Yin, Michael Schaefer, Christoph Arenz (+5 others)
2015 Proceedings of the National Academy of Sciences of the United States of America  
Hypoxic pulmonary vasoconstriction (HPV) optimizes pulmonary ventilation-perfusion matching in regional hypoxia, but promotes pulmonary hypertension in global hypoxia. Ventilation-perfusion mismatch is a major cause of hypoxemia in cystic fibrosis. We hypothesized that cystic fibrosis transmembrane conductance regulator (CFTR) may be critical in HPV, potentially by modulating the response to sphingolipids as mediators of HPV. HPV and ventilation-perfusion mismatch were analyzed in isolated
more » ... lungs or in vivo. Ca 2+ mobilization and transient receptor potential canonical 6 (TRPC6) translocation were studied in human pulmonary (PASMCs) or coronary (CASMCs) artery smooth muscle cells. CFTR inhibition or deficiency diminished HPV and aggravated ventilation-perfusion mismatch. In PASMCs, hypoxia caused CFTR to interact with TRPC6, whereas CFTR inhibition attenuated hypoxiainduced TRPC6 translocation to caveolae and Ca 2+ mobilization. Ca 2+ mobilization by sphingosine-1-phosphate (S1P) was also attenuated by CFTR inhibition in PASMCs, but amplified in CASMCs. Inhibition of neutral sphingomyelinase (nSMase) blocked HPV, whereas exogenous nSMase caused TRPC6 translocation and vasoconstriction that were blocked by CFTR inhibition. nSMase-and hypoxia-induced vasoconstriction, yet not TRPC6 translocation, were blocked by inhibition or deficiency of sphingosine kinase 1 (SphK1) or antagonism of S1P receptors 2 and 4 (S1P 2/4 ). S1P and nSMase had synergistic effects on pulmonary vasoconstriction that involved TRPC6, phospholipase C, and rho kinase. Our findings demonstrate a central role of CFTR and sphingolipids in HPV. Upon hypoxia, nSMase triggers TRPC6 translocation, which requires its interaction with CFTR. Concomitant SphK1-dependent formation of S1P and activation of S1P 2/4 result in phospholipase C-mediated TRPC6 and rho kinase activation, which conjointly trigger vasoconstriction. pulmonary hypertension | neutral sphingomyelinase | ceramide | transient receptor potential canonical 6
doi:10.1073/pnas.1421190112 pmid:25829545 pmcid:PMC4386337 fatcat:p5rsvgvwzrhlfohmknbqzy5pja