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Role of PTEN in Hypoxic Pulmonary Vasoconstriction
Author(s) -
Krauszman Adrienn,
Mak Tak,
Sheppard Dean,
Szaszi Katalin,
Kuebler Wolfgang
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.986.6
Subject(s) - pten , hypoxic pulmonary vasoconstriction , caveolae , tensin , phosphatase , trpc6 , hypoxia (environmental) , trpc , microbiology and biotechnology , pi3k/akt/mtor pathway , chemistry , biology , cancer research , phosphorylation , transient receptor potential channel , signal transduction , endocrinology , vasoconstriction , receptor , biochemistry , organic chemistry , oxygen
Rationale Hypoxic pulmonary vasoconstricition (HPV) optimizes ventilation/perfusion matching in the lung, and critically depends on transient receptor potential canonical (TRPC) 6 activation and trafficking to caveolae. In endothelial cells, phosphatase and tensin homolog (PTEN) has been shown to serve as a scaffold for TRPC6, enabling cell surface expression of the channel and subsequent Ca 2+ entry. Moreover, Rho kinase (ROCK) is known to phosphorylate PTEN and play a role in its localization in chemotaxing neutrophils. Hence, we hypothesized that the interaction between PTEN and TRPC6 in PASMC may be required for TRPC6 translocation to caveolae and an intact HPV response in a ROCK‐dependent manner. Methods Interaction between PTEN and TRPC6 was tested by co‐immunoprecipitation in whole lung lysates, and by proximity ligation assay in pulmonary artery smooth muscle cells (PASMC). Caveolar recruitment of proteins was assessed in PASMC by sucrose density gradient ultracentrifugation. HPV was analyzed in isolated perfused lungs as hypoxia‐induced increase in perfusion pressure. Calcium entry to PASMC was measured by Fura2 imaging. Results SMC specific PTEN KO mice had a lower HPV response compared to WT mice. Similarly, PTEN knock down in PASMC blunted Ca 2+ influx in response to hypoxia. Hypoxia induced protein‐protein interaction between PTEN and TRPC6 in both whole lungs and PASMC, and translocated PTEN to caveolae (caveolin 1‐rich membrane fraction). Inhibition of ROCK (Y27632; 10 μM) prevented both effects and attenuated the HPV response in intact lungs. Conclusion Hypoxia induces PTEN interaction with TRPC6 in PASMC, and PTEN translocation to caveolae in a ROCK‐dependent manner. Our findings identify an important role for PTEN in TRPC6 recruitment and activation downstream of ROCK and thus, in triggering HPV in a manner that is independent of its phosphatase activity. Support or Funding Information Funded by a CIHR operational grant to WMK