Absence of SPARC in murine lens epithelium leads to increased deposition of laminin-1 in lens capsule.
Absence of SPARC in murine lens epithelium leads to increased deposition of laminin-1 in lens capsule.
复制标题
小鼠晶状体上皮中 SPARC 的缺失导致晶状体囊中层粘连蛋白-1 的沉积增加。
DOI：
10.1167/iovs.05-0460
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Sage,EHelene
中科院分区：
文献类型：
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作者：
Yan,Qi;Perdue,Nikole;Blake,David;Sage,EHelene
目的.研究透镜囊中细胞外基质（ECM）蛋白的表达和沉积的调节作用。对胚胎日龄（E）14至3月龄的野生型（SP+/+）和SPARC-无效（SP-/-）小鼠进行了检查。半定量RT-PCR检测透镜上皮细胞mRNA表达水平，分析透镜基底膜（BM）组分的转录水平。免疫组化和Western blot分析透镜囊和透镜上皮细胞中ECM蛋白的表达。通过透镜上皮外植体培养评估细胞附着。进行免疫共沉淀，以确定细胞内的蛋白质相互作用。免疫组化和免疫印迹分析显示，出生后5天至3个月龄，SPARC-null透镜囊相对于野生型晶状体囊表现出更高水平的层粘连蛋白-1沉积。层粘连蛋白-1蛋白的不均匀和聚集分布在无SPARC的透镜囊的前部区域中是明显的。在透镜上皮细胞的内质网（ER）中有丰富的层粘连蛋白-1（laminin-1，LN-1）表达。免疫共沉淀法鉴定，在层粘连蛋白分泌之前，cDNA 3与层粘连蛋白-1结合。此外，增加层粘连蛋白-1在透镜囊促进附着的透镜上皮外植体在文化。晶状体上皮细胞层粘连蛋白-1蛋白的分泌和沉积受晶状体上皮细胞的影响。由于层粘连蛋白-1在透镜BM中的异常沉积可能会影响透镜上皮细胞粘附和纤维细胞分化，因此作者提出SPARC通过调节透镜BM基质组织而对透镜稳态很重要。
purpose. To investigate the role of SPARC in the regulation of the expression and deposition of extracellular matrix (ECM) proteins in the lens capsule.methods. Wild-type (SP+/+) and SPARC-null (SP−/−) mice of embryonic day (E) 14 to 3 months of age were examined. Transcript levels of lens basement membrane (BM) components were analyzed by semiquantitative RT-PCR with mRNA from lens epithelia. Expression of ECM proteins in lens capsule and lens epithelium was analyzed by immunohistochemistry and Western blot analysis. Cell attachment was assessed by lens epithelial explant culture. Coimmunoprecipitation was performed to identify intracellular protein interactions.results. From postnatal day 5 to 3 months of age, SPARC-null lens capsules exhibited higher levels of laminin-1 deposition relative to their wild-type counterparts, as revealed by immunohistochemistry and immunoblot analysis. An uneven and aggregated distribution of laminin-1 protein was apparent in the anterior region of SPARC-null lens capsules. SPARC and laminin-1 were expressed abundantly in the endoplasmic reticulum (ER) of lens epithelial cells. Coimmunoprecipitation identified that SPARC associates with laminin-1 before laminin secretion. Furthermore, increased laminin-1 in lens capsule promoted the attachment of lens epithelial explants in culture.conclusions. SPARC affects the secretion and deposition of laminin-1 protein in lens epithelial cells. Because abnormal deposition of laminin-1 in the lens BM could influence lens epithelial cell adhesion and fiber cell differentiation, the authors propose that SPARC is important to lens homeostasis through its regulation of lens BM matrix organization.