Small leucine rich repeat proteoglycans (SLRPs) in the humansclera: Identification of abundant levels of PRELP

[摘要] Purpose: The small leucine rich proteoglycan (SLRP) family is madeup of several members which are thought to guide matrix assembly andorganization through protein:protein and/or protein:carbohydrateinteractions. In order to better characterize the composition of thescleral extracellular matrix, gene and protein expression of severalmembers of the SLRP family were evaluated in the human sclera fromdonors aged 2-93 years of age.Methods: Semi-quantitative and quantitative RT-PCR analyses wereperformed on RNA isolated from human donor sclera using primers fordecorin, fibromodulin, PRELP (proline arginine rich end leucine-richprotein), biglycan, chondroadherin, and lumican. Additionally, theprotein expression and distribution of the SLRP family member, PRELP,was determined in the human sclera through western blot detection andimmunohistochemistry.Results: Semi-quantitative and quantitative PCR analysis showed thatall six SLRPs were expressed in the human sclera, with PRELP exhibitingthe highest steady state mRNA levels, relative to that of the otherSLRPs (p<0.001, ANOVA). Further analysis of PRELP in the human scleraby western blot analysis indicated that PRELP contained a 45 kDa coreprotein with short unsulfated keratan sulfate side chains and appearedin greatest abundance in sclera during the fourth decade of life.Conclusions: These results suggest that several SLRP proteoglycansare expressed in the human sclera and provide the first description ofthe PRELP protein in the human sclera. The relative abundance of PRELPmRNA and protein in the human sclera, and the observed age-relatedvariation in scleral PRELP expression suggests that PRELP may play acritical role in regulating the biomechanical properties of scleralextracellular matrix.

[学科分类] 生物化学/生物物理