Analysis of the expression of chondroadherin in mouse ocular andnon-ocular tissues

[摘要] Purpose: Chondroadherin (Chad) is a unique member of the smallleucine rich repeat proteoglycan gene family. It is expressed at highlevels in certain zones of cartilage and also has been detected in bone,tendon, bone marrow, and chondrosarcoma cells. Recently, we demonstratedthat Chad is expressed in human and mouse lens and that its expressionis decreased in the absence of mimecan/osteoglycin. This findingprompted us to explore the expression of Chad in other ocular andnon-ocular tissues.Methods: Reverse transcription-polymerase chain reactionamplification (RT-PCR), in situ hybridization (ISH), andimmunohistochemistry (IHC) were used to determine the expression of Chadin human and mouse tissues.Results: RT-PCR analysis showed strong expression of Chad in mousebrain, heart, lung, and embryo. Moderate expression was detected inmouse thymus, spleen, testis, and ovary, and very low expression inkidney and liver. Chad was highly expressed in human cornea, brain, andskeletal muscle, and moderately in human retina and lens. By ISH, ChadmRNA was detected in cornea, lens, and retina of postnatal day 21 mouseeyes. By IHC, immunostaining for Chad was seen in epithelial andendothelial layers of the cornea, as well as in lens, ciliary body, andretina of the adult mouse eye. Strong immunostaining was noted inretinal rod, cone, and plexiform layers. IHC analysis of tissuemicroarray demonstrated presence of Chad in brain (cerebellum), skeletaland cardiac muscles, lung, gastrointestinal tract, ovary, and cartilage.In most tissues, Chad expression was associated with either peripheralnerves and/or blood vessels. In the stomach and intestines, positiveimmunostaining was observed in Meissner's plexus and enteroendocrinecells. Intriguingly, positive immunostaining also was observed inPurkinje cells of the cerebellum and pancreatic islets.Conclusions: The present work establishes the expression andlocalization of Chad in several new locations including cornea, lens,ciliary body, retina, cerebellum, pancreatic islet, blood vessels, andperipheral nerves. The surprisingly broad expression pattern of Chadsuggests potential roles for this protein in cell specific and/ortissues specific function(s). The results reported here are an essentialprerequisite for future studies aimed at understanding the biologicalroles of Chad in health and disease.

[学科分类] 生物化学/生物物理