Inhibition of FOXO1/3 promotes vascular calcification.
Inhibition of FOXO1/3 promotes vascular calcification.
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DOI：
10.1161/atvbaha.114.304786
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发表时间：
2015-01
期刊：
影响因子：
--
通讯作者：
Chen Y
中科院分区：
文献类型：
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作者：
Deng L;Huang L;Sun Y;Heath JM;Wu H;Chen Y
血管钙化是动脉粥样硬化、糖尿病和终末期肾病的特征。我们已经证明，AKT的激活上调Runx 2，这是一个关键的成骨转录因子，对血管平滑肌细胞（VSMC）的钙化至关重要。使用SMC特异性缺失PTEN（AKT的主要负调节因子）的小鼠，本研究揭示了一种新的潜在的分子机制，该机制是PTEN/AKT/FOXO介导的Runx 2上调和VSMC钙化。通过将PTEN floxed小鼠与SM 22 α-Cre转基因小鼠杂交产生SMC特异性PTEN缺失小鼠。PTEN的缺失导致AKT的持续激活，其上调Runx 2并促进体外VSMC钙化和离体动脉钙化。Runx 2基因敲除不影响增殖，但阻断了PTEN缺陷型VSMC的钙化，这表明PTEN缺失促进了Runx 2依赖型VSMC的钙化，而这种钙化与增殖无关。在分子水平上，PTEN缺陷通过抑制Runx 2泛素化而在转录后增加Runx 2的量。AKT激活增加FOXO 1/3的磷酸化，导致FOXO 1/3的核排斥。FOXO 1/3基因敲低可模拟PTEN缺陷，提示FOXO 1/3作为PTEN/AKT的下游信号通路，在调节Runx 2泛素化和VSMC钙化中具有新的功能。使用杂合子SMC特异性PTEN缺陷小鼠和致动脉粥样硬化ApoE−/−小鼠，我们进一步证明了体内血管钙化中的AKT激活，FOXO磷酸化和Runx 2泛素化。我们的研究已经确定了SMC特异性PTEN缺陷对血管钙化的新的致病作用，并证明FOXO 1/3在PTEN/AKT调节的Runx 2泛素化和VSMC钙化中起着至关重要的作用。
Vascular calcification is a characteristic feature of atherosclerosis, diabetes and end-stage renal disease. We have demonstrated that activation of AKT upregulates Runx2, a key osteogenic transcription factor that is crucial for calcification of vascular smooth muscle cells (VSMC). Using mice with SMC-specific deletion of PTEN, a major negative regulator of AKT, the present studies uncovered a novel molecular mechanism underlying PTEN/AKT/FOXO-mediated Runx2 upregulation and VSMC calcification. SMC-specific PTEN deletion mice were generated by crossing PTEN floxed mice with SM22α-Cre transgenic mice. The PTEN deletion resulted in sustained activation of AKT that upregulated Runx2 and promoted VSMC calcification in vitro and arterial calcification ex vivo. Runx2 knockdown did not affect proliferation but blocked calcification of the PTEN deficient VSMC, suggesting that PTEN deletion promotes Runx2-depedent VSMC calcification that is independent of proliferation. At the molecular level, PTEN deficiency increased the amount of Runx2 post-transcriptionally by inhibiting Runx2 ubiquitination. AKT activation increased phosphorylation of FOXO1/3 that led to nuclear exclusion of FOXO1/3. FOXO1/3 knockdown in VSMC phenocopied the PTEN deficiency, demonstrating a novel function of FOXO1/3, as a downstream signaling of PTEN/AKT, in regulating Runx2 ubiquitination and VSMC calcification. Using heterozygous SMC-specific PTEN deficient mice and atherogenic ApoE−/− mice, we further demonstrated AKT activation, FOXO phosphorylation and Runx2 ubiquitination in vascular calcification in vivo. Our studies have determined a new causative effect of SMC-specific PTEN deficiency on vascular calcification, and demonstrated that FOXO1/3 plays a crucial role in PTEN/AKT-modulated Runx2 ubiquitination and VSMC calcification.