Cartilage Oligomeric Matrix Protein Levels in Type 2 Diabetes Associated with Primary Knee Osteoarthritis Patients.

AIMS: (1) To evaluate the association between type 2 diabetes mellitus (T2D) and primary knee osteoarthritis (KOA); and (2) to compare synovial fluid (SF) cartilage oligomeric matrix protein (COMP) concentrations and glycemic control parameters in patients with T2D, with and without primary KOA. METHODS: A total of 231 individuals were included in this study. Primary KOA was confirmed according to the criteria established by the American College of Rheumatology. The presence of T2D was determined by medical history. In addition, fasting plasma glucose and glycated hemoglobin were analyzed to confirm diabetic and nondiabetic status. RESULTS: Our results showed an association between T2D and primary KOA after covariate adjustments (OR = 3.755, p = 0.000024, 95% CI: 2.033-6.934). In addition, SF COMP levels were significantly higher in T2D groups with and without primary KOA (p = 0.00035; p = 0.001 respectively) when compared to nonT2D controls. CONCLUSION: This study suggests a strong association between T2D and primary KOA; in addition, the presence of T2D may have an influence in SF COMP levels in subjects with and without primary KOA. The glycemic control parameters and duration of diabetes may be useful as an indirect indicator of SF COMP levels to prevent the effects of chronic exposure to hyperglycemia and subsequent damage to the articular cartilage.

The role of complement inhibitors beyond controlling inflammation.

The complement system is an arm of innate immunity that aids in the removal of pathogens and dying cells. Due to its harmful, pro-inflammatory potential, complement is controlled by several soluble and membrane-bound inhibitors. This family of complement regulators has been recently extended by the discovery of several new members, and it is becoming apparent that these proteins harbour additional functions. In this review, the current state of knowledge of the physiological functions of four complement regulators will be described: cartilage oligomeric matrix protein (COMP), CUB and sushi multiple domains 1 (CSMD1), sushi domain-containing protein 4 (SUSD4) and CD59. Complement activation is involved in both the development of and defence against cancer. COMP expression is pro-oncogenic, whereas CSMD1 and SUSD4 act as tumour suppressors. These effects may be related in part to the complex influence of complement on cancer but also depend on unrelated functions such as the protection of cells from endoplasmic reticulum stress conveyed by intracellular COMP. CD59 is the main inhibitor of the membrane attack complex, and its deficiency leads to complement attack on erythrocytes and severe haemolytic anaemia, which is now amenable to treatment with an inhibitor of C5 cleavage. Unexpectedly, the intracellular pool of CD59 is crucial for insulin secretion from pancreatic ß-cells. This finding is one of several relating to the intracellular functions of complement proteins, which until recently were only considered to be present in the extracellular space. Understanding the alternative functions of complement inhibitors may unravel unexpected links between complement and other physiological systems, but is also important for better design of therapeutic complement inhibition.

Thrombospondin-1, -2 and -5 have differential effects on vascular smooth muscle cell physiology.

INTRODUCTION: The thrombospondins (TSPs) are matricellular proteins that exert multifunctional effects by binding cytokines, cell-surface receptors and other proteins. TSPs play important roles in vascular pathobiology and are all expressed in arterial lesions. The differential effects of TSP-1, -2, and -5 represent a gap in knowledge in vascular smooth muscle cell (VSMC) physiology. Our objective is to determine if structural differences of the TSPs imparted different effects on VSMC functions critical to the formation of neointimal hyperplasia. We hypothesize that TSP-1 and -2 induce similar patterns of migration, proliferation and gene expression, while the effects of TSP-5 are different. METHODS: Human aortic VSMC chemotaxis was tested for TSP-2 and TSP-5 (1-40 µg/mL), and compared to TSP-1 and serum-free media (SFM) using a modified Boyden chamber. Next, VSMCs were exposed to TSP-1, TSP-2 or TSP-5 (0.2-40 µg/mL). Proliferation was assessed by MTS assay. Finally, VSMCs were exposed to TSP-1, TSP-2, TSP-5 or SFM for 3, 6 or 24 h. Quantitative real-time PCR was performed on 96 genes using a microfluidic card. Statistical analysis was performed by ANOVA or t-test, with p < 0.05 being significant. RESULTS: TSP-1, TSP-2 and TSP-5 at 20 µg/mL all induce chemotaxis 3.1 fold compared to serum-free media. TSP-1 and TSP-2 induced proliferation 53% and 54% respectively, whereas TSP-5 did not. In the gene analysis, overall, cardiovascular system development and function is the canonical pathway most influenced by TSP treatment, and includes multiple growth factors, cytokines and proteases implicated in cellular migration, proliferation, vasculogenesis, apoptosis and inflammation pathways. CONCLUSIONS AND RELEVANCE: The results of this study indicate TSP-1, -2, and -5 play active roles in VSMC physiology and gene expression. Similarly to TSP-1, VSMC chemotaxis to TSP-2 and -5 is dose-dependent. TSP-1 and -2 induces VSMC proliferation, but TSP-5 does not, likely due conservation of N-terminal domains in TSP-1 and -2. In addition, TSP-1, -2 and -5 significantly affect VSMC gene expression; however, little overlap exists in the specific genes altered. This study further delineates TSP-1, -2 and -5's contributions to processes related to VSMC physiology.

Cartilage oligomeric matrix protein (COMP)-mediated cell differentiation to proteolysis mechanism networks from human normal adjacent tissues to lung adenocarcinoma.

BACKGROUND: To understand cartilage oligomeric matrix protein (COMP) mechanism network from human normal adjacent tissues to lung adenocarcinoma. METHODS: COMP complete different activated (all no positive correlation, Pearson CC < 0.25) and uncomplete (partly no positive correlation except COMP, Pearson CC < 0.25) network were identified in higher lung adenocarcinoma compared with lower human normal adjacent tissues from the corresponding COMP-stimulated (≥0.25) or inhibited (Pearson CC ≤ -0.25) overlapping molecules of Pearson correlation coefficient (CC) and GRNInfer, respectively. COMP complete different activated and inhibited (all no positive correlation, Pearson CC < 0.25) mechanisms networks of higher lung adenocarcinoma and lower human normal adjacent tissues were constructed by integration of Pearson CC, GRNInfer and GO. As visualized by integration of GO, KEGG, GenMAPP, BioCarta and Disease, we deduced COMP complete different activated and inhibited network in higher lung adenocarcinoma and lower human normal adjacent tissues. RESULTS: As visualized by GO, KEGG, GenMAPP, BioCarta and disease database integration, we proposed mainly that the mechanism and function of COMP complete different activated network in higher lung adenocarcinoma was involved in COMP activation with matrix-localized insulin-like factor coupling carboxypeptidase to metallopeptidase-induced proteolysis, whereas the corresponding inhibited network in lower human normal adjacent tissues participated in COMP inhibition with nucleus-localized vasculogenesis, B and T cell differentiation and neural endocrine factors coupling pyrophosphatase-mediated proteolysis. However, COMP complete different inhibited network in higher lung adenocarcinoma included COMP inhibition with nucleus-localized chromatin maintenance, licensing and assembly factors coupling phosphatase-inhibitor to cytokinesis regulators-mediated cell differentiation, whereas the corresponding activated network in lower human normal adjacent tissues contained COMP activation with cytolplasm-localized translation elongation factor coupling fucosyltransferase to ubiquitin-protein ligase-induced cell differentiation. CONCLUSION: COMP different networks were verified not only by complete and uncomplete COMP activated or inhibited networks within human normal adjacent tissues or lung adenocarcinoma, but also by COMP activated and inhibited network between human normal adjacent tissues and lung adenocarcinoma.