Chiarelli Nicola, Carini Giulia, Zoppi Nicoletta, Ritelli Marco, Colombi Marina
Department of Molecular and Translational Medicine, Division of Biology and Genetics, University of Brescia, Brescia, Italy.
PLoS One. 2018 Jan 18;13(1):e0191220. doi: 10.1371/journal.pone.0191220. eCollection 2018.
Vascular Ehlers-Danlos syndrome (vEDS) is a dominantly inherited connective tissue disorder caused by mutations in the COL3A1 gene that encodes type III collagen (COLLIII), which is the major expressed collagen in blood vessels and hollow organs. The majority of disease-causing variants in COL3A1 are glycine substitutions and in-frame splice mutations in the triple helix domain that through a dominant negative effect are associated with the severe clinical spectrum potentially lethal of vEDS, characterized by fragility of soft connective tissues with arterial and organ ruptures. To shed lights into molecular mechanisms underlying vEDS, we performed gene expression profiling in cultured skin fibroblasts from three patients with different structural COL3A1 mutations. Transcriptome analysis revealed significant changes in the expression levels of several genes involved in maintenance of cell redox and endoplasmic reticulum (ER) homeostasis, COLLs folding and extracellular matrix (ECM) organization, formation of the proteasome complex, and cell cycle regulation. Protein analyses showed that aberrant COLLIII expression is associated with the disassembly of many structural ECM constituents, such as fibrillins, EMILINs, and elastin, as well as with the reduction of the proteoglycans perlecan, decorin, and versican, all playing an important role in the vascular system. Furthermore, the altered distribution of the ER marker protein disulfide isomerase PDI and the strong reduction of the COLLs-modifying enzyme FKBP22 are consistent with the disturbance of ER-related homeostasis and COLLs biosynthesis and post-translational modifications, indicated by microarray analysis. Our findings add new insights into the pathophysiology of this severe vascular disorder, since they provide a picture of the gene expression changes in vEDS skin fibroblasts and highlight that dominant negative mutations in COL3A1 also affect post-translational modifications and deposition into the ECM of several structural proteins crucial to the integrity of soft connective tissues.
血管型埃勒斯-当洛综合征（vEDS）是一种常染色体显性遗传的结缔组织疾病，由编码III型胶原蛋白（COLLIII）的COL3A1基因突变引起，III型胶原蛋白是血管和中空器官中主要表达的胶原蛋白。COL3A1基因中大多数致病变体是甘氨酸替代和三螺旋结构域中的框内剪接突变，这些突变通过显性负效应与vEDS潜在致命的严重临床谱相关，其特征是软结缔组织脆弱并伴有动脉和器官破裂。为了深入了解vEDS潜在的分子机制，我们对三名具有不同COL3A1结构突变的患者的培养皮肤成纤维细胞进行了基因表达谱分析。转录组分析显示，参与维持细胞氧化还原和内质网（ER）稳态、胶原蛋白折叠和细胞外基质（ECM）组织、蛋白酶体复合物形成以及细胞周期调控的几个基因的表达水平发生了显著变化。蛋白质分析表明，异常的COLLIII表达与许多结构性ECM成分的分解有关，如原纤维蛋白、表皮微丝蛋白和弹性蛋白，也与蛋白聚糖（基底膜聚糖、核心蛋白聚糖和多功能蛋白聚糖）的减少有关，这些成分在血管系统中都起着重要作用。此外，ER标记蛋白二硫键异构酶PDI分布的改变以及胶原蛋白修饰酶FKBP22的显著减少与ER相关稳态以及胶原蛋白生物合成和翻译后修饰的紊乱一致，这一点通过微阵列分析得到了证实。我们的研究结果为这种严重血管疾病的病理生理学提供了新的见解，因为它们描绘了vEDS皮肤成纤维细胞中的基因表达变化，并突出了COL3A1中的显性负突变也会影响翻译后修饰以及几种对软结缔组织完整性至关重要的结构蛋白向ECM的沉积。
