Carnosol Inhibits Pro-Inflammatory and Catabolic Mediators of Cartilage Breakdown in Human Osteoarthritic Chondrocytes and Mediates Cross-Talk between Subchondral Bone Osteoblasts and Chondrocytes

PLoS One. 2015 Aug 20;10(8):e0136118. doi: 10.1371/journal.pone.0136118. eCollection 2015.

Abstract

Aim: The aim of this work was to evaluate the effects of carnosol, a rosemary polyphenol, on pro-inflammatory and catabolic mediators of cartilage breakdown in chondrocytes and via bone-cartilage crosstalk.

Materials and methods: Osteoarthritic (OA) human chondrocytes were cultured in alginate beads for 4 days in presence or absence of carnosol (6 nM to 9 μM). The production of aggrecan, matrix metalloproteinase (MMP)-3, tissue inhibitor of metalloproteinase (TIMP)-1, interleukin (IL)-6 and nitric oxide (NO) and the expression of type II collagen and ADAMTS-4 and -5 were analyzed. Human osteoblasts from sclerotic (SC) or non-sclerotic (NSC) subchondral bone were cultured for 3 days in presence or absence of carnosol before co-culture with chondrocytes. Chondrocyte gene expression was analyzed after 4 days of co-culture.

Results: In chondrocytes, type II collagen expression was significantly enhanced in the presence of 3 μM carnosol (p = 0.008). MMP-3, IL-6, NO production and ADAMTS-4 expression were down-regulated in a concentration-dependent manner by carnosol (p<0.01). TIMP-1 production was slightly increased at 3 μM (p = 0.02) and ADAMTS-5 expression was decreased from 0.2 to 9 μM carnosol (p<0.05). IL-6 and PGE2 production was reduced in the presence of carnosol in both SC and NSC osteoblasts while alkaline phosphatase activity was not changed. In co-culture experiments preincubation of NSC and SC osteoblasts wih carnosol resulted in similar effects to incubation with anti-IL-6 antibody, namely a significant increase in aggrecan and decrease in MMP-3, ADAMTS-4 and -5 gene expression by chondrocytes.

Conclusions: Carnosol showed potent inhibition of pro-inflammatory and catabolic mediators of cartilage breakdown in chondrocytes. Inhibition of matrix degradation and enhancement of formation was observed in chondrocytes cocultured with subchondral osteoblasts preincubated with carnosol indicating a cross-talk between these two cellular compartments, potentially mediated via inhibition of IL-6 in osteoblasts as similar results were obtained with anti-IL-6 antibody.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abietanes / pharmacology*
  • Aggrecans / immunology
  • Anti-Inflammatory Agents / pharmacology*
  • Cell Survival / drug effects
  • Cells, Cultured
  • Chondrocytes / drug effects*
  • Chondrocytes / immunology
  • Chondrocytes / pathology*
  • Coculture Techniques
  • Dinoprostone / immunology
  • Humans
  • Interleukin-6 / immunology
  • Matrix Metalloproteinase 3 / immunology
  • Osteoarthritis / drug therapy*
  • Osteoarthritis / immunology*
  • Osteoarthritis / pathology
  • Osteoblasts / drug effects
  • Osteoblasts / immunology
  • Osteoblasts / pathology
  • Tissue Inhibitor of Metalloproteinase-1 / immunology

Substances

  • Abietanes
  • Aggrecans
  • Anti-Inflammatory Agents
  • Interleukin-6
  • Tissue Inhibitor of Metalloproteinase-1
  • carnosol
  • MMP3 protein, human
  • Matrix Metalloproteinase 3
  • Dinoprostone

Grants and funding

This project received a grant from Nestec. Nestec chose the compounds and doses evaluated in this study. Yves Henrotin who is the head of BCRU, received the funding. The funders also participated in study design, decision to publish and preparation of the manuscript preparation. Nestle provided support in the form of salaries for authors MNH, FMS, LA and EO, but did not have role in the data collection and analysis.