Kantorow M, Huang Q, Yang X J, Sage E H, Magabo K S, Miller K M, Horwitz J
Department of Biology, West Virginia University, Morgantown, WV 26505, USA.
Mol Vis. 2000 Apr 5;6:24-9.
We have previously reported increased levels of Osteonectin/SPARC transcript in age-related cataractous compared to normal human lenses. The purpose of the present study was to evaluate the corresponding levels of osteonectin/SPARC protein in age-related cataractous relative to normal lenses and to evaluate the levels of osteonectin/SPARC transcript in specific types of age-related human cataracts. The spatial expression of osteonectin/SPARC was also evaluated in normal human lenses.
Specific types of age-related cataracts were collected and graded. Normal human lenses were microdissected into epithelia and fibers. Osteonectin/SPARC protein levels were monitored by Western immunoblotting, and transcript levels were evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). Osteonectin/SPARC expression patterns were examined by RT-PCR and by immunostaining.
Higher levels of osteonectin/SPARC protein were detected in age-related cataractous relative to normal human lenses. Increased levels of osteonectin/SPARC transcript were also detected in posterior-subcapsular and nuclear cataractous lenses relative to normal lenses. Osteonectin/SPARC transcripts were detected in the lens epithelium but not fibers. Osteonectin/SPARC protein levels were highest in the peripheral lens epithelium.
Consistent with our previous studies on osteonectin/SPARC mRNA levels, osteonectin/SPARC protein levels were also elevated in cataractous compared to normal human lenses. Increased levels of osteonectin/SPARC mRNA were also found in nuclear and posterior-subcapsular cataracts relative to normal lenses. Osteonectin/SPARC expression is confined to the lens epithelium, and osteonectin/SPARC levels are highest in the peripheral lens epithelium.
我们之前报道过，与正常人类晶状体相比，年龄相关性白内障中骨连接蛋白/富含半胱氨酸的酸性分泌蛋白（Osteonectin/SPARC）转录水平升高。本研究的目的是评估年龄相关性白内障相对于正常晶状体中骨连接蛋白/SPARC蛋白的相应水平，并评估特定类型的年龄相关性人类白内障中骨连接蛋白/SPARC转录水平。还评估了骨连接蛋白/SPARC在正常人类晶状体中的空间表达。
收集特定类型的年龄相关性白内障并进行分级。将正常人类晶状体显微切割为上皮和纤维。通过蛋白质免疫印迹法监测骨连接蛋白/SPARC蛋白水平，通过逆转录聚合酶链反应（RT-PCR）评估转录水平。通过RT-PCR和免疫染色检查骨连接蛋白/SPARC的表达模式。
相对于正常人类晶状体，在年龄相关性白内障中检测到更高水平的骨连接蛋白/SPARC蛋白。相对于正常晶状体，在后囊下和核性白内障晶状体中也检测到骨连接蛋白/SPARC转录水平升高。在晶状体上皮中检测到骨连接蛋白/SPARC转录本，但在纤维中未检测到。骨连接蛋白/SPARC蛋白水平在晶状体周边上皮中最高。
与我们之前关于骨连接蛋白/SPARC mRNA水平的研究一致，与正常人类晶状体相比，白内障中骨连接蛋白/SPARC蛋白水平也升高。相对于正常晶状体，在核性和后囊下白内障中也发现骨连接蛋白/SPARC mRNA水平升高。骨连接蛋白/SPARC表达局限于晶状体上皮，且骨连接蛋白/SPARC水平在晶状体周边上皮中最高。
