Inhibition of vascular calcification by block of intermediate conductance calcium-activated potassium channels with TRAM-34

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• 作者：Christian Freise^a ; ^{christian.freise@charite.de" class="auth_mail} ; Uwe Querfeld^a ; ^b ; ^{uwe.querfeld@charite.de" class="auth_mail}
• 关键词：ALP ; alkaline phosphatase ; CKD ; chronic kidney disease ; KCa ; Ca2+-activated K+-channels ; KCa3.1 ; intermediate conductance Ca2+-activated K+-channels ; MMP ; matrix-metalloproteinase ; NF-魏B ; nuclear factor-kappa B ; TGF-尾1 ; transforming growth factor beta 1 ; TNF-伪 ; tumor necrosis factor alpha ; TRAM-34 ; 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole ; specific KCa3.1 inhibitor ; VOCC ; voltage-operated Ca2+ channels ; VSMC ; vascular smooth muscle cell
• 刊名：Pharmacological Research
• 出版年：July 2014
• 年：2014
• 卷：85
• 期：Complete
• 页码：6-14
• 全文大小：2162 K

文摘

Vascular calcifications are a hallmark of advanced cardiovascular disease in patients with chronic kidney disease. A key event is the transition of contractile vascular smooth muscle cells (VSMC) into an osteoblast-like phenotype, promoting a coordinated process of vascular remodeling resembling bone mineralization. Intermediate-conductance calcium-activated potassium channels (KCa3.1) are expressed in various tissues including VSMC. Aiming for novel therapeutic targets in vascular calcification, we here studied effects of KCa3.1-inhibition on VSMC calcification by the specific KCa3.1 inhibitor TRAM-34.

15">Calcification in the murine VSMC cell line MOVAS-1 and primary rat VSMC was induced by calcification medium (CM) containing elevated levels of PO₄³⁻ and Ca²⁺. Cell signaling, calcification markers, and release of nitric oxide and alkaline phosphatase were assessed by luciferase reporter plasmids, RT-PCR and specific enzymatic assays, respectively. KCa3.1 gene silencing was achieved by siRNA experiments.

TRAM-34 at 10 nmol/l, decreased CM-induced calcification and induced NO release of VSMC accompanied by decreased TGF-尾 signaling. The CM-induced mRNA expressions of osterix, osteocalcin, matrix-metalloproteinases (MMP)-2/-9 were reduced by TRAM-34 while osteopontin expression was increased. Further, TRAM-34 attenuated the CM- and TNF-伪-induced activation of NF-魏B and reduced the release of MMP-2/-9 by VSMC. Finally, TRAM-34 abrogated CM-induced apoptosis and KCa3.1 gene silencing protected VSMC from CM-induced onset of calcification.

In summary, TRAM-34 interferes with calcification relevant signaling of NF-魏B and TGF-尾 thereby blocking the phenotypic transition/calcification of VSMC.

We conclude that the results provide a rationale for further studies regarding a possible therapeutic role of KCa3.1 inhibition by TRAM-34 or other inhibitors in vascular calcification.