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Loss of Jak2 impairs endothelial function by attenuating Raf-1/MEK1/Sp-1 signaling along with altered eNOS activities

Ping Yang1, Yawen Zhang, Junfeng Pang

  • 1Center for Biomedical Research, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

The American Journal of Pathology
|June 11, 2013
PubMed

Insights

Janus kinase 2 (Jak2) is crucial for adult blood vessel function. Loss of Jak2 impairs blood vessel relaxation, growth, and repair after injury, impacting endothelial homeostasis and recovery.

Area of Science:

  • Vascular Biology
  • Molecular Medicine
  • Physiology

Background:

  • The precise role of Janus kinase 2 (Jak2) in maintaining adult endothelial homeostasis remains unclear due to conflicting results from inhibitor studies.
  • Jak2 deficiency causes embryonic lethality, necessitating models to study its postnatal functions in endothelial cells.

Purpose of the Study:

  • To elucidate the specific role of Jak2 in regulating postnatal endothelial function and homeostasis.
  • To investigate the impact of Jak2 deficiency on vascular responses, angiogenesis, and ischemic injury recovery.

Main Methods:

  • Generation of a tamoxifen-inducible Jak2-deficient adult mouse model.
  • Assessment of endothelium-dependent vasodilation, in vivo angiogenesis using Matrigel plug assays, and hindlimb ischemia models.
  • Analysis of perfusion recovery, neovascularization, and expression of key proteins like eNOS via antibody arrays and signaling pathway analysis.

Main Results:

  • Jak2 deficiency significantly impaired endothelium-dependent vasodilation and reduced angiogenic capacity.
  • Loss of Jak2 delayed perfusion recovery in a hindlimb ischemia model, with decreased capillary and arteriole formation.
  • Jak2 deficiency repressed eNOS expression by attenuating the Raf-1/MEK1/Sp-1 signaling pathway.

Conclusions:

  • Jak2 is essential for normal postnatal endothelial function, including vasodilation, angiogenesis, and ischemic repair.
  • The Jak2-eNOS pathway, involving Raf-1/MEK1/Sp-1 signaling, is critical for endothelial homeostasis and vascular recovery.
  • Targeting Jak2 may offer therapeutic potential for conditions involving vascular dysfunction.

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