Open Access

Uric acid enhances PKC-dependent eNOS phosphorylation and mediates cellular ER stress: A mechanism for uric acid-induced endothelial dysfunction

  • Authors:
    • Peng Li
    • Lina Zhang
    • Mei Zhang
    • Changyong Zhou
    • Nan Lin
  • View Affiliations

  • Published online on: February 18, 2016     https://doi.org/10.3892/ijmm.2016.2491
  • Pages: 989-997
  • Copyright: © Li et al. This is an open access article distributed under the terms of Creative Commons Attribution License.

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Abstract

The mechanism by which hyperuricemia induced-endothelial dysfunction contributes to cardiovascular diseases (CVDs) is not yet fully understood. In the present study, we used uric acid (UA) to trigger endothelial dysfunction in cultured endothelial cells, and investigated the effects of induced reactive oxygen species (ROS) generation, endoplasmic reticulum (ER) stress induction, and the protein kinase C (PKC)-dependent endothelial nitric oxide synthase (eNOS) signaling pathway. Human umbilical vein endothelial cells (HUVECs) were incubated with 6, 9 or 12 mg/dl UA, ROS scavenger polyethylene glycol-superoxide dismutase (PEG‑SOD), ER stress inhibitor 4-phenylbutyric acid (4-PBA), and PKC inhibitor polymyxin B for 6-48 h. Nitric oxide (NO) production, eNOS activity, intracellular ROS, ER stress levels, and the interaction between eNOS and calmodulin (CaM) and cytosolic calcium levels were assessed using fluorescence microscopy and western blot analysis. Apoptosis was assessed by annexin V staining. UA increased HUVEC apoptosis and reduced eNOS activity and NO production in a dose- and time-dependent manner. Intracellular ROS was elevated after 3 h, while ER stress level increased after 6 h. UA did not alter intracellular Ca2+, CaM, or eNOS concentration, or eNOS Ser1177 phosphorylation. However, PKC-dependent eNOS phosphorylation at Thr495 was greatly enhanced, and consequently interaction between eNOS and CaM was reduced. Cellular ROS depletion, ER stress inhibition and PKC activity reduction inhibited the effect of UA on eNOS activity, NO release and apoptosis in HUVECs. Thus, we concluded that UA induced HUVEC apoptosis and endothelial dysfunction by triggering oxidative and ER stress through PKC/eNOS-mediated eNOS activity and NO production.

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April-2016
Volume 37 Issue 4

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Li P, Zhang L, Zhang M, Zhou C and Lin N: Uric acid enhances PKC-dependent eNOS phosphorylation and mediates cellular ER stress: A mechanism for uric acid-induced endothelial dysfunction. Int J Mol Med 37: 989-997, 2016
APA
Li, P., Zhang, L., Zhang, M., Zhou, C., & Lin, N. (2016). Uric acid enhances PKC-dependent eNOS phosphorylation and mediates cellular ER stress: A mechanism for uric acid-induced endothelial dysfunction. International Journal of Molecular Medicine, 37, 989-997. https://doi.org/10.3892/ijmm.2016.2491
MLA
Li, P., Zhang, L., Zhang, M., Zhou, C., Lin, N."Uric acid enhances PKC-dependent eNOS phosphorylation and mediates cellular ER stress: A mechanism for uric acid-induced endothelial dysfunction". International Journal of Molecular Medicine 37.4 (2016): 989-997.
Chicago
Li, P., Zhang, L., Zhang, M., Zhou, C., Lin, N."Uric acid enhances PKC-dependent eNOS phosphorylation and mediates cellular ER stress: A mechanism for uric acid-induced endothelial dysfunction". International Journal of Molecular Medicine 37, no. 4 (2016): 989-997. https://doi.org/10.3892/ijmm.2016.2491