Matheson S, Larjava H, Häkkinen L
Department of Oral Biological and Medical Sciences, Laboratory of Periodontal Biology, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada.
J Periodontal Res. 2005 Aug;40(4):312-24. doi: 10.1111/j.1600-0765.2005.00800.x.
Small leucine-rich proteoglycans (SLRPs) decorin, biglycan, fibromodulin and lumican are secreted extracellular matrix molecules that associate with fibrillar collagens and regulate collagen fibrillogenesis. Collagens are the major extracellular matrix components of periodontal connective tissues where they provide mechanical attachment of the tooth to the bone and gingiva and mediate signals that regulate cell functions, including remodeling of the periodontal ligament and bone. Structural organization of collagen may also be important for the defense against periodontal disease, because in certain conditions abnormal collagen fibrils associate with increased susceptibility to periodontal disease.
The purpose of this study was to find out the role of SLRPs to regulate collagen fibril and fibril bundle formation in periodontal tissues.
The localization of SLRPs in human and mouse periodontal tissues was studied using immunohistochemical methods. To assess the function of SLRPs we studied periodontal tissues of mice harboring targeted deletions of decorin, fibromodulin or lumican genes and lumican and fibromodulin double knockout mice using histological and electronmicroscopical methods.
The SLRPs were coexpressed in human and mouse gingival and periodontal ligament connective tissues where they colocalized with collagen fibril bundles. Teeth in the knockout animals were fully erupted and showed normal gross morphology. Targeted deletion of decorin, fibromodulin, lumican or both lumican and fibromodulin resulted in abnormal collagen fibril and fibril bundle morphology that was most evident in the periodontal ligament. Each of the gene deletions resulted in a unique fibril and fibril bundle phenotype.
These findings indicate that decorin, fibromodulin and lumican coordinately regulate the fibrillar and suprafibrillar organization of collagen in the periodontal ligament.
富含亮氨酸的小分子蛋白聚糖（SLRPs），包括核心蛋白聚糖、双糖链蛋白聚糖、纤调蛋白和光蛋白聚糖，是分泌型细胞外基质分子，它们与纤维状胶原结合并调节胶原纤维形成。胶原是牙周结缔组织的主要细胞外基质成分，在牙周结缔组织中，胶原提供牙齿与骨和牙龈的机械附着，并介导调节细胞功能的信号，包括牙周韧带和骨的重塑。胶原的结构组织对于抵御牙周疾病可能也很重要，因为在某些情况下，异常的胶原纤维与牙周疾病易感性增加有关。
本研究旨在探究SLRPs在调节牙周组织中胶原纤维和纤维束形成方面的作用。
采用免疫组织化学方法研究SLRPs在人和小鼠牙周组织中的定位。为评估SLRPs的功能，我们使用组织学和电子显微镜方法研究了缺失核心蛋白聚糖、纤调蛋白或光蛋白聚糖基因的小鼠以及光蛋白聚糖和纤调蛋白双敲除小鼠的牙周组织。
SLRPs在人和小鼠牙龈及牙周韧带结缔组织中共同表达，并与胶原纤维束共定位。基因敲除动物的牙齿完全萌出，外观形态正常。核心蛋白聚糖、纤调蛋白、光蛋白聚糖或光蛋白聚糖与纤调蛋白两者的靶向缺失均导致胶原纤维和纤维束形态异常，这在牙周韧带中最为明显。每个基因缺失都导致了独特的纤维和纤维束表型。
这些发现表明，核心蛋白聚糖、纤调蛋白和光蛋白聚糖协同调节牙周韧带中胶原的纤维和超纤维组织。
