Loss of interleukin-21 receptor activation in hypoxic endothelial cells impairs perfusion recovery after hindlimb ischemia.
Loss of interleukin-21 receptor activation in hypoxic endothelial cells impairs perfusion recovery after hindlimb ischemia.
复制标题
缺氧内皮细胞中白介素-21受体激活的丧失会损害后肢缺血后的灌注恢复。
DOI：
10.1161/atvbaha.115.305476
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发表时间：
2015-05
期刊：
影响因子：
--
通讯作者：
Annex BH
中科院分区：
文献类型：
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作者：
Wang T;Cunningham A;Dokun AO;Hazarika S;Houston K;Chen L;Lye RJ;Spolski R;Leonard WJ;Annex BH
手术后小鼠后肢缺血（HLI）已成为研究外周动脉疾病（PAD）有价值的临床前模型。我们之前已经发现，近交系小鼠HLI的不同表型结果与小鼠7号染色体短臂上的一个区域有关。编码白介素-21受体（IL-21R）的基因位于该区域的关联高峰。通过定量RT-PCR，我们发现HLI后IL-21R上调能力较大的小鼠品系比HLI后IL-21R未上调的品系有更好的灌注恢复。C57BL/6小鼠后肢缺血组织免疫荧光染色显示内皮细胞（EC）表达IL-21R。从缺血后肢肌肉中分离的ec富集部分比从非缺血肢体中分离的ec富集部分显示更高的Il-21R水平。体外实验表明，人脐静脉EC （HUVEC）在缺氧和血清饥饿后IL-21R表达升高。在这些条件下，IL-21处理增加了细胞活力，减少了细胞凋亡，增加了管的形成。在体内，在C57BL/6小鼠中，敲除Il21r或通过IL-21R-Fc（阻断IL-21与其受体结合的融合蛋白）处理阻断IL-21信号传导都会导致HLI后灌注恢复减少。体外和体内在缺氧条件下对IL-21/IL-21R轴的调节导致stat3磷酸化增加，BCL-2/BAX比值随之增加。我们的数据表明，在缺氧的内皮细胞中，IL-21R上调和配体激活可能通过STAT3通路限制/阻止细胞凋亡和/或促进细胞存活和血管生成，从而帮助灌注恢复。
Surgical hindlimb ischemia (HLI) in mice has become a valuable preclinical model to study peripheral arterial disease (PAD). We previously identified that the different phenotypical outcomes following HLI across inbred mouse strains is related a region on the short arm of mouse chromosome 7. The gene coding the interleukin-21 receptor (IL-21R) lies at the peak of association in this region. With quantitative RT-PCR, we found that a mouse strain with a greater ability to up-regulate IL-21R following HLI had better perfusion recovery than a strain with no up-regulation after HLI. Immunofluorescent staining of ischemic hind-limb tissue showed IL-21R expression on endothelial cells (EC) from these C57BL/6 mice. An EC-enriched fraction isolated from ischemic hind-limb muscle showed higher Il-21R levels than an EC-enriched fraction from non-ischemic limbs. In-vitro, human umbilical vein EC (HUVEC) showed elevated IL-21R expression after hypoxia and serum starvation. Under these conditions, IL-21 treatment increased cell viability, decreased cell apoptosis, and augmented tube formation. In-vivo, either knockout Il21r or blocking IL-21 signaling by treating with IL-21R-Fc (fusion protein that blocks IL-21 binding to its receptor) in C57BL/6 mice resulted in less perfusion recovery after HLI. Both in-vitro and in-vivo modulation of the IL-21/IL-21R axis under hypoxic conditions resulted in increasedSTAT3 phosphorylation and a subsequent increase in the BCL-2/BAX ratio. Our data indicate that IL-21R up-regulation and ligand activation in hypoxic endothelial cells may help perfusion recovery by limiting/preventing apoptosis and/or favoring cell survival and angiogenesis through the STAT3 pathway.