Background:Synovial fibrosis is a pathological process observed in several musculoskeletal disorders that contributes to articular pain and stiffness. It is characterized by the excessive deposition of extracellular matrix, as well as cell migration and proliferation, being TGF-β main inductor of these processes. Fucoidans are sulfated polysaccharide obtained mainly from various species of brown algae and brown seaweed such as Fucus vesiculosus, Undaria pinnatifida, or Macrocystis pyrifera. Recent studies show that fucoidans are promising candidates to address the symptoms of OA. Although a wide spectrum of biological activities has been registered in these polysaccharides, their properties vary between fucoidans from different species.Objectives:Our aim was to evaluate and to compare the anti-fibrotic effects of different fucoidans on fibroblast-like synoviocytes (FLS).Methods:FLS were isolated from OA patients. Primary cultured cells were treated with fucoidans from Fucus vesiculosus (FF), Undaria pinnatifida (FU) and Macrocystis pyrifera (FM) at 5, 30. To activate pro-fibrotic pathways, cells were stimulated with TGF-β and cell viability and proliferation were analyzed by MTT and BrdU assay, respectively. Then gene expression of extracellular matrix proteins, collagen I and III and fibronectin, as well as plod2b, gene coding for alterative splice-variant of lysyl hydroxylases LDH2b, were evaluated by RT-qPCR. The presence of fibrotic maker, alpha smooth muscle actin (α-sma), was analyzed by immunocytochemistry and intracellular collagen levels were assessed by picrosirius red staining. Wound-clousure and transwell cell invasion assay were also performed to evaluate the capacity of cell motility and invasiveness.Figure 1.Measurement of expression of pro-fibrotic markersResults:TGF-β induced a clear pro-fibrotic response (Figure 1). Cell proliferation induced by TGF-β was attenuated in the presence of all tested fucoidans. These polysaccharides also reduced the gene expression of TGF-β-elicited collagen I and III (p< 0.05), although FF failed to downregulate fibronectin levels and none of them showed modulation of plod2b expression. Results were confirmed at protein level. FF30 and FM5 reduced intracellular collagen accumulation induced by TGF-β (p< 0.05). Likewise, the expression of a-sma in TGFb-activated FLS was significantly diminished in the presence of all fucoidans (p< 0.05). By scratch wound assay, we observed that TGF-b induced cell mobility to close the scratch, which was inhibited by all fucoidans. Similarly, FU and FM were also able to attenuated cell invasion after TGF stimulation. Additionally, we also detected that fucoidans showed anti-inflammatory effects in FLS as they reduced the NO production and IL-6 expression induced by IL-1.Conclusion:Our results indicate a protective effect of fucoidans against activated pro-fibrotic pathways in fibroblast-like synoviocytes. However, we detected that these beneficial activities vary between fucoidans from different species and further studies are warranted.Disclosure of Interests:Carlos Vaamonde García: None declared, Herminia Domínguez: None declared, Francisco J. Blanco Grant/research support from: Sanofi-Aventis, Lilly, Bristol MS, Amgen, Pfizer, Abbvie, TRB Chemedica International, Glaxo SmithKline, Archigen Biotech Limited, Novartis, Nichi-iko pharmaceutical Co, Genentech, Jannsen Research & Development, UCB Biopharma, Centrexion Theurapeutics, Celgene, Roche, Regeneron Pharmaceuticals Inc, Biohope, Corbus Pharmaceutical, Tedec Meiji Pharma, Kiniksa Pharmaceuticals, Ltd, Gilead Sciences Inc, Consultant of: Lilly, Bristol MS, Pfizer, Rosa Meijide Failde: None declared
Carbocatalysed hydrolytic cleaving of the glycosidic bond in fucoidan under microwave irradiation
