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WNK1 Protein Kinase Regulates Embryonic Cardiovascular Development through the OSR1 Signaling Cascade
Journal article   Open access   Peer reviewed

WNK1 Protein Kinase Regulates Embryonic Cardiovascular Development through the OSR1 Signaling Cascade

Jian Xie, Joonho Yoon, Sung-Sen Yang, Shih-Hua Lin and Chou-Long Huang
The Journal of biological chemistry, Vol.288(12), pp.8566-8574
03/22/2013
DOI: 10.1074/jbc.M113.451575
PMCID: PMC3605675
PMID: 23386621
url
https://doi.org/10.1074/jbc.M113.451575View
Published (Version of record) Open Access

Abstract

WNK1 is a widely expressed serine/threonine protein kinase that regulates multiple cellular and organ functions via diverse mechanisms. We previously reported that endothelial-specific deletion of Wnk1 in mice results in embryonic lethality, with angiogenesis and cardiac defects beginning at embryonic day ∼10.5. Here, we further investigated the signaling mechanism by which WNK1 regulates embryonic cardiovascular development. We found that mice with a global deletion of Osr1, which encodes oxidative stress-responsive kinase-1, a protein kinase activated by WNK1, died in utero beginning at embryonic day ∼11. The defects in Osr1-null yolk sacs and embryos were virtually identical to those observed in Wnk1-knock-out mice: no mature large vessels in yolk sacs, defective angiogenesis in the brain and intersomitic vessels, and smaller chambers and reduced myocardial trabeculation in mutant hearts. Endothelial-specific deletion of Osr1 generated by crossing Osr1flox/flox mice with Tie2-Cre mice phenocopied defects caused by global Osr1 deletion. To investigate whether OSR1 acts downstream of WNK1 in embryonic angiogenesis, we generated a mouse line that carries a catalytically and constitutively active human OSR1 transgene in the ROSA26 locus under the control of a cassette of floxed transcription stop codons. We found that endothelial-specific expression of the constitutively active mutant OSR1, generated by Tie2-Cre-mediated excision of floxed stop codons in the mutated ROSA26 locus, rescued angiogenesis and cardiac defects in global Wnk1-null embryos. These results indicate that WNK1 activation of the OSR1 signaling cascade is an essential pathway that regulates angiogenesis and cardiac formation during mouse embryo development. Background: WNK1 is critical for embryonic cardiovascular development. Results: A global deletion of Osr1 in mice phenocopies the Wnk1 deletion; expression of the constitutively active mutant OSR1 rescues developmental defects in Wnk1-null embryos. Conclusion: WNK1 activation of OSR1 is essential for mouse embryo development. Significance: The WNK1-OSR1 signaling cascade is a novel pathway that regulates embryonic angiogenesis and cardiac formation.
Angiogenesis Transgenic Mice Protein Kinases WNK1 OSR1 Development Cardiac Development

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