Syndecans and Enzymes for Heparan Sulfate Biosynthesis and Modification Differentially Correlate With Presence of Inflammatory Infiltrate in Periodontitis

Abstract

Periodontitis is a common degenerative disease initiated by the bacteria in subgingival biofilm. The exposure to bacterial biofilm triggers host inflammatory response whose dysregulation is ultimately responsible for the destruction of hard and soft periodontal tissues resulting in tooth loss. To date, significant effort has been invested in the research of the involvement of host cells and inflammatory mediators in regulation of inflammatory response in periodontitis. Syndecans (Sdcs) belong to a four-member family of heparan sulfate proteoglycans (HSPGs). Sdcs are compound molecules comprised of the core protein to which several heparan sulfate (HS) glycosaminoglycan (GAG) chains are attached. The role of Sdcs in pathogenesis of periodontitis is poorly investigated despite the numerous reports from experimental studies about the critical involvement of these factors in modulation of various aspects of inflammatory response, such as the formation of inflammatory mediators gradients, leukocyte recruitment and extracellular matrix remodeling in resolution of inflammation. Most of these functions of Sdcs are HS-related and, thus, dependent upon the structure of HS. This, in turn, is determined by the combinatorial action of enzymes for biosynthesis and modification of HS such as exostosis (EXTs), sulfotransferases (NDSTs), and heparanase 1 (HPSE1). The data presented in this study clearly indicate that some Sdcs display different expression profiles in healthy and diseased periodontal tissue. Additionally, the differences in expression profiles of HS GAG biosynthesis and modification enzymes (EXTs, NDSTs, and HPSE1) in healthy and diseased periodontal tissue imply that changes in HS GAG content and structure might also take place during periodontitis. Most notably, expression profiles of Sdcs, EXTs, NDSTs, and HPSE1 differentially correlate with the presence of inflammatory infiltrate in healthy and diseased periodontal tissue, which might imply that these factors could also be involved in modulation of inflammatory response in periodontitis.

Correlation of the expression of hyaluronan and CD44 with the presence of gingival inflammatory infiltrate in advanced generalized periodontitis

“…However, the analysis of signal distribution in tissue compartments (epithelial and stromal expression domains) found a slightly reduced HA and CD44 expression in the epithelium of the diseased gingiva (this reduction was not statistically significant) and, simultaneously, a statistically significant increase of HA and CD44 expression in the subepithelial stroma in diseased gingiva when compared to the healthy gingiva. Accordingly, based on results from our previous study, cumulative changes in the stromal expression of HA and CD44 in the subepithelial stroma of the gingiva of subjects with advanced generalized periodontitis occur simultaneously with the increased presence of inflammatory infiltrate [15]. On the other hand, no correlation was found between the overall spatial distribution of either HA or CD44 and the presence of inflammatory infiltrate in the diseased gingiva, which can be explained by the fact that HA and CD44 are ubiquitously expressed in both gingival tissue compartments -along with inflammatory cells, other gingival cell populations (epithelial cells, vascular endothelial cells, fibrocytes) express these factors as well ( Figure 5).…”

“…Based on an analysis of the general inflammatory cell marker CD45 expression from a previous study, the presence of stromal inflammatory infiltrate was significantly higher in gingival samples collected from subjects with advanced generalized periodontitis when compared to that of the healthy gingiva, where inflammatory infiltrate was scarce and narrowly limited to the perivascular tissue [15]. Since HA and CD44 play a regulatory role in the formation and maintenance of inflammatory infiltrate, the correlation between the spatial gradients of total HA and CD44 expression and the spatial gradient of total CD45…”

“…The Alcian Blue sections were used in a preliminary histo-morphometric analysis of the ratio of epithelial and stromal tissue sections in the whole-section area of individual sections. Based on the results of this analysis, the selection of samples was confirmed for further processing under the criteria listed above [15].…”

“…Panoramic images were edited, rotated, and resized in Adobe Photoshop® CC (2019) on a high-resolution (600 dpi) background, as previously described, to preserve data resolution when reducing the image size [15]. Jolla, CA, USA).…”

Novel approach for quantification of multiple immunofluorescent signals using histograms and 2D plot profiling of whole-section panoramic images

“…Gingiva samples were obtained from patients diagnosed with general destructive periodontitis. Patient screening and recruitment were done in accordance with the guidelines for classification of periodontal and peri-implant diseases as described previously 26 , 27 . The sampled tissue was free gingiva which is a part of masticatory gingiva that spans from the gingival margin to the ridge of the alveolar bone.…”