Large chondroitin sulfate proteoglycans were first identified in hyaline cartilage, where they specifically interact with hyaluronan and
form large supramolecular complexes. Together with other matrix glycoproteins, they provide mechanical support and a fixed
negative charge. The core protein of fibroblast chondroitin
sulfate proteoglycan was designated versican in recognition of its versatile modular structure. Decorin (125255) and biglycan
(301870) are 2 other soft tissue proteoglycans. Decorin and biglycan (301870) are related but distinct small proteoglycans found in many connective tissues.
The protein encoded by this gene is a small cellular or pericellular matrix proteoglycan that is closely related in structure to biglycan protein. The encoded protein and biglycan are thought to be the result of a gene duplication. This protein is a component of connective tissue, binds to type I collagen fibrils, and plays a role in matrix assembly. It contains one attached glycosaminoglycan chain. This protein is capable of suppressing the growth of various tumor cell lines. There are multiple alternatively spliced transcript variants known for this gene. This gene is a candidate gene for Marfan syndrome. [provided by RefSeq, Jul 2008]
Decorin is a part of the ovarian extracellular matrix in primates and may act as a signaling molecule. Adam M et al. STUDY QUESTIONIs decorin (DCN), a putative modulator of growth factor (GF) signaling, expressed in the primate ovary and does it play a role in ovarian biology?SUMMARY ANSWERDCN expression in the theca, the corpus luteum (CL), its presence in the follicular fluid (FF) and its actions revealed in human IVF-derived granulosa cells (GCs), suggest that it plays multiple roles in the ovary including folliculogenesis, ovulation and survival of the CL.WHAT IS KNOWN ALREADYDCN is a secreted proteoglycan, which has a structural role in the extracellular matrix (ECM) and also interferes with the signaling of multiple GF/GF receptors (GFRs). However, DCN expression and action in the primate ovary has yet to be determined.STUDY DESIGN, SIZE, DURATIONArchival human and monkey ovarian samples were analyzed. Studies were conducted using FF and GC samples collected from IVF patients.PARTICIPANTS/MATERIALS, SETTING, METHODSImmunohistochemistry, western blotting, RT-PCR, quantitative RT-PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA) studies were complemented by cellular studies, including the measurements of intracellular Ca(2+), reactive oxygen species (ROS), epidermal GF receptor (EGFR) phosphorylation by DCN and caspase activity.MAIN RESULTS AND THE ROLE OF CHANCEImmunohistochemistry revealed strong DCN staining in the connective tissue and follicular thecal compartments, but not in GCs of pre-antral and antral follicles. Pre-ovulatory follicles could not be studied, but DCN was associated with connective tissue of CL samples and the cytoplasm of luteal cells. DCN expression in monkey CL doubled (P < 0.05) towards the end of the luteal lifespan. DCN was found in human FF obtained from IVF patients (mean: 12.9 ng/ml; n = 20) as determined by ELISA. DCN mRNA and/or protein were detected in freshly isolated and cultured, luteinized human GCs. In the latter, exogenous human recombinant DCN increased intracellular Ca(2+) levels and induced the production of ROS in a concentration-dependent manner. DCN, like epidermal GF, phosphorylated EGFR significantly (P < 0.05) and reduced the activity of caspase 3/7 in cultured GCs. The data indicate the expression of DCN in the theca of growing follicles, in FF of ovulatory follicles and in the CL. Therefore, DCN may exert paracrine actions via GF/GFR systems in multiple ovarian compartments.LIMITATIONS, REASONS FOR CAUTIONFunctional studies were performed in cultures of human luteinized GCs, which are an apt model but may not fully mirror the pre-ovulatory GC compartment or the CL. Other human ovarian cells, including the thecal cells, were not available.WIDER IMPLICATIONS OF THE FINDINGSIn accordance with its evolving roles in other organs, ovarian DCN is an ECM-associated component, which acts as a multifunctional regulator of GF signaling in the primate ovary. DCN may thus be involved in folliculogenesis, ovulation and the regulation of the CL survival in primates.STUDY FUNDING/COMPETING INTEREST(S)This study was supported by Deutsche Forschungsgemeinschaft (DFG) MA1080/17-3 and in part DFG MA1080/21-1 (to AM), NIH grants HD24870 (S.R.O. and R.L.S.), the Eunice Kennedy Shriver NICHD/NIH through cooperative agreement HD18185 as part of the Specialized Cooperative Centers Program in Reproduction and Infertility Research (S.R.O.) and 8P51OD011092-53 for the operation of the Oregon National Primate Research Center (G.A.D., J.D.H., S.R.O. and R.L.S).