Leptin alone and in combination with interleukin-1-beta induced cartilage degradation potentially inhibited by EPA and DHA

Osteoarthritis (OA) is the most common form of arthritis. Obesity has been believed to be an important risk factor for OA development and the progression of not only load-bearing joints, but low-load-bearing joints as well. Increased leptin has been the focus of a link between obesity and OA. In this study, the effects of pathological (100ng/ml) or supra-pathological (10μg/ml) concentrations of leptin alone or in combination with IL1β on cartilage metabolisms were studied in porcine cartilage explant. The involved mechanisms were examined in human articular chondrocytes (HACs). Moreover, the protective effect of omega-3 polyunsaturated acids, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) was also investigated. Leptin (10μg/ml) alone or in combination with IL1β could induce cartilage destruction, although lower concentrations had no effect. Leptin activated NFκB, ERK, JNK and p38 in HACs, which led to the induction of MMP3, MMP13 and ADAMTS4 secretions. The combined effect could further induce those enzymes through the additive effect on activation of NFκB and JNK. Interestingly, both EPA and DHA could inhibit cartilage damage induced by leptin plus IL1β by reducing the activation of NFκB and JNK, which led to the decrease of ADAMTS4 secretion. Altogether, only a supra-pathological concentration of leptin alone or in combination with IL1β could induce cartilage destruction, whereas a pathological one could not. This effect could be inhibited by EPA and DHA. To gain greater understanding of the link between leptin and OA, the effect of different levels of leptin on several states of OA cartilage requires further investigation.

Ex vivo model exhibits protective effects of sesamin against destruction of cartilage induced with a combination of tumor necrosis factor-alpha and oncostatin M

Background

Rheumatoid arthritis (RA) is an autoimmune disease associated with chronic inflammatory arthritis. TNF-α and OSM are pro-inflammatory cytokines that play a key role in RA progression. Thus, reducing the effects of both cytokines is practical in order to relieve the progression of the disease. This current study is interested in sesamin, an active compound in sesame seeds. Sesamin has been shown to be a chondroprotective agent in osteoarthritis models. Here, we have evaluated a porcine cartilage explant as a cartilage degradation model related to RA induced by TNF-α and/or OSM in order to investigate the effects of sesamin on TNF-α and OSM in the cartilage degradation model.

Methods

A porcine cartilage explant was induced with a combination of TNF-α and OSM (test group) or IL-1β and OSM (control group) followed by a co-treatment of sesamin over a long-term period (35 days). After which, the tested explants were analyzed for indications of both the remaining and the degradation aspects using glycosaminoglycan and collagen as an indicator.

Results

The combination of TNF-α and OSM promoted cartilage degradation more than either TNF-α or OSM alone and was comparable with the combination of IL-1β and OSM. Sesamin could be offering protection against cartilage degradation by reducing GAGs and collagen turnover in the generated model.

Conclusions

Sesamin might be a promising agent as an alternative treatment for RA patients. Furthermore, the generated model revealed itself to be an impressive test model for the analysis of phytochemical substances against the cartilage degradation model for RA. The model could be used to test for the prevention of cartilage degradation in other biological agents induced with TNF-α and OSM as well.

Sesamin stimulates osteoblast differentiation through p38 and ERK1/2 MAPK signaling pathways

BACKGROUND

Osteoporosis is a worldwide health problem predominantly affecting post-menopausal women. Therapies aimed at increasing bone mass in osteoporetic patients lag behind comparable investigation of therapeutic strategies focusing on the bone resorption process. Sesamin, a major lignan compound found in Sesamun indicum Linn., has a variety of pharmacological effects, though its activity on bone cell function is unclear. Herein we examine the effect of this lignan on osteoblast differentiation and function.

METHOD

Cell cytotoxicity and proliferative in hFOB1.19 were examined by MTT and alamar blue assay up to 96 h of treatment. Gene expression of COL1, ALP, BMP-2, Runx2, OC, RANKL and OPG were detected after 24 h of sesamin treatment. ALP activity was measured at day 7, 14 and 21 of cultured. For mineralized assay, ADSCs were cultured in the presence of osteogenic media supplement with or without sesamin for 21 days and then stained with Alizarin Red S. MAPK signaling pathway activation was observed by using western blotting.

RESULTS

Sesamin promoted the gene expression of COL1, ALP, OCN, BMP-2 and Runx2 in hFOB1.19. On the other hand, sesamin was able to up-regulate OPG and down-regulate RANKL gene expression. ALP activity also significantly increased after sesamin treatment. Interestingly, sesamin induced formation of mineralized nodules in adipose derived stem cells (ADSCs) as observed by Alizarin Red S staining; this implies that sesamin has anabolic effects both on progenitor and committed cell stages of osteoblasts. Western blotting data showed that sesamin activated phosphorylation of p38 and ERK1/2 in hFOB1.19.

CONCLUSIONS

The data suggest that sesamin has the ability to trigger osteoblast differentiation by activation of the p38 and ERK MAPK signaling pathway and possibly indirectly regulate osteoclast development via the expression of OPG and RANKL in osteoblasts. Therefore, sesamin may be a promising phytochemical that could be developed for supplementation of osteoporotic therapy.