Genetic studies in the mouse have highlighted essential roles for several growth factors in skin repair and have offered a rationale for their use in therapy. The present study shows that the plasminogen-related growth factor HGF/SF (hepatocyte growth factor/scatter factor) promotes wound repair in homozygous diabetic db/db mice by recruiting neutrophils, monocytes, and mast cells to the wound; by promoting the migration of endothelial cells to the injured area; and by enhancing keratinocyte migration and proliferation. As a result, granulation tissue formation, wound angiogenesis, and re-epithelialization are all increased. The results demonstrate that HGF/SF affects and sustains all key cellular processes responsible for wound repair and point to a unique potential of this molecule for the therapy of chronic skin wounds.
A number of studies have shown elevated matrix metalloproteinase expression in chronic wound fluid compared to an acute wound; however, little has been done to characterize animal models in a similar manner and thus determine their usefulness. The diabetes mouse is an animal model of type II diabetes that shows impaired dermal wound healing and has been proposed as a model of human impaired wound healing. In this study we have determined the mRNA and protein expression profiles of matrix metalloproteinases 2, 3, and 9 during the first 10 d of dermal healing for the diabetes mouse and its normally healing littermate. Additionally, human wound fluid from diabetic chronic wounds and acute surgical wounds were studied to enable a comparison of the model to the human condition. We show that during the early stages of wound healing the diabetes mouse possesses significantly reduced protein levels of pro-matrix metalloproteinases 2 and 9 within the wound tissue and active matrix metalloproteinase 3 within the fluid. Pro-matrix metalloproteinase 3 levels are also significantly reduced in the diabetes mouse during the later stages of healing. These differences may be contributing to the impaired healing of the diabetes mouse; however, they differ from the human data presented here, which show elevated matrix metalloproteinase 2 and reduced matrix metalloproteinase 9 in human diabetic chronic wound fluid compared to acute wound fluid. Therefore, although clearly showing the importance of appropriate matrix metalloproteinase regulation for normal acute wound healing to occur, the diabetes mouse may not be an ideal model for study of matrix metalloproteinase involvement in human chronic wound healing.
Objectives WISP3/CCN6 is mutated in progressive pseudorheumatoid dysplasia and may have effects on cartilage homeostasis. In order to uncover further roles for WISP3/CCN6 its expression was explored in osteoarthritic cartilage. Effects of WISP3/CCN6 on cartilage-relevant metalloproteinase expression were investigated in immortalised (C-28/I2) and primary chondrocytes. Methods Cartilage steady state levels of WISP3/CCN6 mRNA and protein production were determined by quantitative RT-PCR and immunohistochemistry respectively. WISP3/CCN6 was over-expressed in C-28/I2 cells and resultant stable clones analysed by real time RT-PCR for metalloproteinase expression and signalling pathways involved explored with pharmacological inhibition. Effects of WISP3/CCN6 on metalloproteinase expression in primary chondrocytes were investigated by an siRNA approach. Results WISP3/CCN6 was highly expressed in osteoarthritic cartilage compared to undamaged cartilage at RNA and protein levels. WISP3/CCN6 over-expression in C-28/I2 cells resulted in unexpected dual regulation of metalloproteinases: the expression of the potent aggrecanase, ADAMTS5, was down-regulated 9-fold, whilst MMP10 was up-regulated 14-fold, responses accentuated by suspension culture. MMP10 up-regulation was dependent on several MAP kinases but WISP3/CCN6-mediated ADAMTS5 repression was independent of these pathways and partially relieved by activation of β-catenin signalling. WISP3/CCN6 also suppressed ADAMTS5 expression in C-28/I2 cells treated with cytokines. In cytokine-treated primary chondrocytes gene silencing of WISP3/CCN6 resulted in enhanced ADAMTS5 expression whilst MMP10 expression was suppressed. Conclusion WISP3/CCN6 was highly expressed in end-stage osteoarthritic cartilage suggesting a role for this growth factor in cartilage homeostasis. WISP3/CCN6 repression of ADAMTS5 expression and regulation of MMP10 expression suggests complex and context-dependent roles for WISP3/CCN6 in cartilage biology.
Non-alcoholic fatty liver disease (NAFLD) affects 25% of adults and at present no licensed medication has been approved. Despite its complex patho-physiology, dietary strategies aiming at delaying or preventing NAFLD have taken a reductionist approach, examining the impact of single components. Accumulating evidence suggests that n-3 LC-PUFAs are efficacious in regulating lipogenesis and fatty acid oxidation. In addition, plant derived flavonoids are also emerging as a dietary strategy for NAFLD prevention, with efficacy attributed to their insulin sensitising and indirect antioxidant effects. Based on knowledge of their complementary molecular targets, we aimed to demonstrate that the combination of n-3 LC-PUFA (n-3) and flavan-3-ols (FLAV) prevents NAFLD. In a high-fat high-fructose (HF/HFr) fed C57Bl/6J mouse model, the independent and interactive impact of n-3 and FLAV on histologically defined NAFLD, insulin sensitivity, weight gain, intestinal and hepatic gene expression, intestinal bile acids were examined. Only the combination of FLAV and n-3 (FLAVn-3) prevented steatosis as evidenced by a strong reduction in hepatocyte ballooning. While FLAV reduced body (-28-30%), adipose tissue (-45-50%) weights and serum insulin (-22-25%) as observed following an intra-peritoneal glucose tolerance test, n-3 downregulated the expression of Srebf1 and the lipogenic genes (Acaca, Fasn). Significant impacts of interventions on intestinal bile acid metabolism, farnesoid X receptor (Fxr) signalling in the intestine and liver, and hepatic expression of fatty acid transporters (Fabp4, Vldlr, Cd36) were also evident. FLAVn-3 may be a novel intervention for NAFLD. Future research should aim to demonstrate its efficacy in the prevention and treatment of human NAFLD.
Matrix metalloproteinases (MMP) are a family of more than 25 zinc‐dependent enzymes that are centrally involved in cellular migration, tissue remodeling, cancer invasion and metastasis. Besides degrading extracellular matrix proteins, MMPs are crucial for growth factor and cytokine release and activation. At the same time, they can inactivate inflammatory mediators and enzymes themselves through protein degradation. Subclasses of MMPs include collagenases, gelatinases, stromelysins, membrane‐bound MMPs, and others. With regard to the stromelysin subfamily, three members exist, e.g., stromelysin‐1 (MMP‐3), stromelysin‐2 (MMP‐10), and stromelysin‐3 (MMP‐11). MMP‐3, and MMP‐10 share extensive similarities at the amino acid level that made it difficult to develop specific antibodies distinguishing between MMP‐3 and MMP‐10. Scrutinizing published data on and performing different analyses with detection of both stromelysins with commercially available or lab‐made antibodies showed ambiguous results with regard to specificity of antibodies used to date. We developed new specific antibodies against the most divergent parts of the active forms of both proteins. We assessed the specificity of our novel specific anti‐human and anti‐mouse MMP‐3 and MMP‐10 antibodies in cell lysates and different human and murine skin tissues. Tests analyzing specificity of the novel antibodies included Western immunoblotting, immunofluorescence, and immunohistochemistry on paraffin sections. Analyses demonstrated specific detection of respective protein for human or mouse samples except for the anti‐human MMP‐3 antibody. The aim of this summary was to call attention the MMP research community to distinguish clearly between both enzymes. Our new specific anti‐mouse MMP‐3 and both MMP‐10 antibodies allow us to address this detection problem and to enable comparative studies between both stromelysins with regard to their respective location and function in the tissue.
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