Caesalpinia sappan extract inhibits IL1ß-mediated overexpression of matrix metalloproteinases in human chondrocytes.

Exacerbated production of matrix metalloproteinases (MMPs) is a key event in the progression of osteoarthritis (OA) and represents a promising target for the management of OA with nutraceuticals. In this study, we sought to determine the MMP-inhibitory activity of an ethanolic Caesalpinia sappan extract (CSE) in human OA chondrocytes. Thus, human articular chondrocytes isolated from OA cartilage and SW1353 chondrocytes were stimulated with Interleukin-1beta (IL1ß), without or with pretreatment with CSE. Following viability assays, the production of MMP-2 and MMP-13 was assessed using ELISA, whereas mRNA levels of MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-13 and TIMP-1, TIMP-2, TIMP-3 were quantified using RT-qPCR assays. Chondrocytes were co-transfected with a MMP-13 luciferase reporter construct and NF-kB p50 and p65 expression vectors in the presence or absence of CSE. In addition, the direct effect of CSE on the proteolytic activities of MMP-2 was evaluated using gelatin zymography. We found that CSE significantly suppressed IL1ß-mediated upregulation of MMP-13 mRNA and protein levels via abrogation of the NF-kB(p65/p50)-driven MMP-13 promoter activation. We further observed that the levels of IL1ß-induced MMP-1, MMP-3, MMP-7, and MMP-9 mRNA, but not TIMP mRNA levels, were down-regulated in chondrocytes in response to CSE. Zymographic results suggested that CSE did not directly interfere with the proteolytic activity of MMP-2. In summary, this study provides evidence for the MMP-inhibitory potential of CSE or CSE-derived compounds in human OA chondrocytes. The data indicate that the mechanism of this inhibition might, at least in part, involve targeting of NF-kB-mediated promoter activation.

Anti-inflammatory activity of an ethanolic Caesalpinia sappan extract in human chondrocytes and macrophages.

ETHNOPHARMACOLOGICAL RELEVANCE: Caesalpinia sappan is a common remedy in Traditional Chinese Medicine and possesses diverse biological activities including anti-inflammatory properties. Osteoarthritis (OA) is a degenerative joint disease with an inflammatory component that drives the degradation of cartilage extracellular matrix. In order to provide a scientific basis for the applicability of Caesalpinia sappan in arthritic diseases, the present study aimed to assess the effects of an ethanolic Caesalpinia sappan extract (CSE) on human chondrocytes and macrophages. MATERIALS AND METHODS: Primary human chondrocytes were isolated from cartilage specimens of OA patients. Primary cells, SW1353 chondrocytes and THP-1 macrophages were serum-starved and pretreated with different concentrations of CSE prior to stimulation with 10 ng/ml of interleukin-1beta (IL-1ß) or lipopolysaccharide (LPS). Following viability tests, nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α) were evaluated by Griess assay and ELISA, respectively. Using validated real-time PCR assays, mRNA levels of IL-1ß, TNF-α, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) were quantified. SW1353 cells were cotransfected with a COX-2 luciferase reporter plasmid and nuclear factor-kappa-B (NF-κB) p50 and p65 expression vectors in the presence or absence of CSE. RESULTS: CSE dose-dependently inhibited the expression of pro-inflammatory cytokines IL-1ß and TNF-α in IL-1ß-stimulated chondrocytes and LPS-stimulated THP-1 macrophages. CSE further suppressed the synthesis of NO in primary OA chondrocytes by blocking iNOS mRNA expression. The inhibition of COX-2 transcription was found to be related with the CSE inhibition of the p65/p50-driven transactivation of the COX-2 promoter. CONCLUSIONS: The present report is first to demonstrate the anti-inflammatory activity of CSE in an in vitro cell model of joint inflammation. CSE can effectively abrogate the IL-1ß-induced over-expression of inflammatory mediators at the transcriptional level in human chondrocytes and macrophages, most likely by inhibiting NF-κB (p65/p50) signaling. Blockade of IL-1ß-induced NF-κB signaling and its downstream pro-inflammatory targets by CSE may be beneficial for reducing cartilage breakdown in arthritis.

IL-1beta and TNF-alpha alter the glycophenotype of primary human chondrocytes in vitro.

Despite the significance of glycoproteins for extracellular matrix assembly in cartilage tissue, little is known about the regulation of the chondrocyte glycophenotype under inflammatory conditions. The present study aimed to assess the effect of IL-1beta and TNF-alpha on specific features of the glycophenotype of primary human chondrocytes in vitro. Using LC-MS, we found that both cytokines increased overall sialylation of N- and O-glycans and induced a shift towards alpha-(2-->3)-linked sialic acid residues in chondrocyte glycoproteins. These results were supported by quantitative PCR showing increased expression of alpha-(2-->3) sialyltransferases in treated cells. Moreover, we found that both IL-1beta and TNF-alpha induced a considerable shift from oligomannosidic glycans towards complex-type N-glycans. In contrast, core alpha-(1-->6)-fucosylation of chondrocyte N-glycans was found to be reduced particularly by TNF-alpha. In summary, inflammatory conditions induce specific alterations of the chondrocyte glycophenotype which might affect cell-matrix interactions or the function of endogenous lectins.