Label-Free Quantitative Proteomics Reveals Survival Mechanisms Developed by Hypertrophic Chondrocytes under ER Stress
Label-Free Quantitative Proteomics Reveals Survival Mechanisms Developed by Hypertrophic Chondrocytes under ER Stress
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DOI：
10.1021/acs.jproteome.5b00537
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发表时间：
2016-01-01
影响因子：
4.4
通讯作者：
Chan, Danny
中科院分区：
文献类型：
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作者：
Kudelko, Mateusz;Chan, Cecilia W. L.;Chan, Danny
新出现的证据表明，软骨细胞中未折叠的突变蛋白引起的ER应激是软骨发育不良的潜在病理学。ER应激在由错误折叠的突变型胶原X蛋白引起的Schmid型干骺端软骨发育不良（MODS）的小鼠模型（13 del）中的肥大软骨细胞（HC）中被触发，但HC不经历凋亡;相反，软骨细胞分化被改变，引起骨骼异常。目前尚不清楚13 del HC如何逃避细胞凋亡并在ER应激中生存。在这里，我们比较了从13 del生长板分离的HC与正常HC的蛋白质组，使用无标记的定量质谱方法。差异表达蛋白的途径富集分析显示，在13 del HC以及表达wt和13 del胶原X的ATDCS细胞系中，糖酵解和ER-线粒体途径发生了显著变化。在体内，我们发现线粒体钙通道的表达减少，而线粒体膜极性保持在13 del软骨细胞，而在体外，葡萄糖摄取保持。我们提出13 del HC的生存机制，即在ER-线粒体通讯的变化减少进口的钙耦合到线粒体膜极性的维护。这些发现为我们理解软骨发育不良发病机制中蛋白质错误折叠引起的生长板变化提供了初步见解。
Emerging evidence implicates ER stress caused by unfolded mutant proteins in chondrocytes as the underlying pathology of chondrodysplasias. ER stress is triggered in hypertrophic chondrocytes (HCs) in a mouse model (13del) of metaphyseal chondrodysplasia type Schmid (MODS) caused by misfolded mutant collagen X proteins, but the HCs do not undergo apoptosis; rather chondrocyte differentiation is altered, causing skeletal abnormality. How 13del HCs can escape from apoptosis and survive ER stress is not understood. Here we compared the proteomes of HCs isolated from 13del growth plates with normal HCs using a label-free quantitative mass spectrometry approach. Pathway enrichment analyses of differentially expressed proteins showed significant changes in glycolysis and ER-mitochondria pathways in 13del HCs as well as in ATDCS cell lines expressing wt and 13del collagen X. In vivo, we showed expression of mitochondrial calcium channels was reduced while mitochondrial membrane polarity was maintained in 13del chondrocytes, while in vitro, glucose uptake was maintained. We propose 13del HCs survive by a mechanism whereby changes in ER-mitochondria communication reduce import of calcium coupled to maintenance of mitochondrial membrane polarity. These findings provide the initial insights into our understanding of growth plate changes caused by protein misfolding in the pathogenesis of chondrodysplasias.