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Pathogenic role of basic calcium phosphate crystals in destructive arthropathies.

Ea HK, Chobaz V, Nguyen C, Nasi S, van Lent P, Daudon M, Dessombz A, Bazin D, McCarthy G, Jolles-Haeberli B, Ives A, Van Linthoudt D, So A, Lioté F, Busso N - PLoS ONE (2013)

Bottom Line: BCP crystal-induced synovitis was totally independent of IL-1α and IL-1β signalling and no alterations of inflammation were observed in mice deficient for components of the NLRP3-inflammasome, IL-1α or IL-1β.Similarly, treatment with anakinra did not prevent BCP crystal effects.The effects are independent of IL-1 and NLRP3 inflammasome.

View Article: PubMed Central - PubMed

Affiliation: INSERM, UMR-S 606, Hospital Lariboisière, Paris, France.

ABSTRACT

Background: basic calcium phosphate (BCP) crystals are commonly found in osteoarthritis (OA) and are associated with cartilage destruction. BCP crystals induce in vitro catabolic responses with the production of metalloproteases and inflammatory cytokines such as interleukin-1 (IL-1). In vivo, IL-1 production induced by BCP crystals is both dependant and independent of NLRP3 inflammasome. We aimed to clarify 1/ the role of BCP crystals in cartilage destruction and 2/ the role of IL-1 and NLRP3 inflammasome in cartilage degradation related to BCP crystals.

Methodology principal findings: synovial membranes isolated from OA knees were analysed by alizarin Red and FTIR. Pyrogen free BCP crystals were injected into right knees of WT, NLRP3 -/-, ASC -/-, IL-1α -/- and IL-1β-/- mice and PBS was injected into left knees. To assess the role of IL-1, WT mice were treated by intra-peritoneal injections of anakinra, the IL-1Ra recombinant protein, or PBS. Articular destruction was studied at d4, d17 and d30 assessing synovial inflammation, proteoglycan loss and chondrocyte apoptosis. BCP crystals were frequently found in OA synovial membranes including low grade OA. BCP crystals injected into murine knee joints provoked synovial inflammation characterized by synovial macrophage infiltration that persisted at day 30, cartilage degradation as evidenced by loss of proteoglycan staining by Safranin-O and concomitant expression of VDIPEN epitopes, and increased chondrocyte apoptosis. BCP crystal-induced synovitis was totally independent of IL-1α and IL-1β signalling and no alterations of inflammation were observed in mice deficient for components of the NLRP3-inflammasome, IL-1α or IL-1β. Similarly, treatment with anakinra did not prevent BCP crystal effects. In vitro, BCP crystals elicited enhanced transcription of matrix degrading and pro-inflammatory genes in macrophages.

Conclusions significance: intra-articular BCP crystals can elicit synovial inflammation and cartilage degradation suggesting that BCP crystals have a direct pathogenic role in OA. The effects are independent of IL-1 and NLRP3 inflammasome.

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Related in: MedlinePlus

OCP crystals induce macrophage expression of genes involved in inflammation and cartilage degradation.Bone marrow derived macrophages were stimulated in vitro with 500 µg/ml of OCP crystals for 4 hours. RNA was extracted, reverse transcribed and qRT-PCR performed using gene specific primers with Tbp, and Gapdh as reference genes. Results are expressed as the fold induction of OCP treated over unstimulated macrophages, using the mean ± S.E.M of triplicate samples.
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pone-0057352-g004: OCP crystals induce macrophage expression of genes involved in inflammation and cartilage degradation.Bone marrow derived macrophages were stimulated in vitro with 500 µg/ml of OCP crystals for 4 hours. RNA was extracted, reverse transcribed and qRT-PCR performed using gene specific primers with Tbp, and Gapdh as reference genes. Results are expressed as the fold induction of OCP treated over unstimulated macrophages, using the mean ± S.E.M of triplicate samples.

Mentions: In view of the predominant macrophage infiltrate within the synovium of OCP injected mice, we hypothesized that crystals induce the expression of macrophage genes that lead to cartilage damage. We stimulated bone marrow derived macrophages from mice with OCP crystals, and analysed by qRT-PCR the expression of inflammatory cytokine and matrix modifying genes (Figure 4).We found dramatically increased expression (>10x compared to control) of ADAMTS4, syndecan 1 (SDC1), MMP3 and 9, CXCL1 and CXCL2, as well as the cytokines ILA, IL1B, IL6 and TNFA. The alarmins S100A8 and A9 were also upregulated significantly (Figure 4).


Pathogenic role of basic calcium phosphate crystals in destructive arthropathies.

Ea HK, Chobaz V, Nguyen C, Nasi S, van Lent P, Daudon M, Dessombz A, Bazin D, McCarthy G, Jolles-Haeberli B, Ives A, Van Linthoudt D, So A, Lioté F, Busso N - PLoS ONE (2013)

OCP crystals induce macrophage expression of genes involved in inflammation and cartilage degradation.Bone marrow derived macrophages were stimulated in vitro with 500 µg/ml of OCP crystals for 4 hours. RNA was extracted, reverse transcribed and qRT-PCR performed using gene specific primers with Tbp, and Gapdh as reference genes. Results are expressed as the fold induction of OCP treated over unstimulated macrophages, using the mean ± S.E.M of triplicate samples.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585350&req=5

pone-0057352-g004: OCP crystals induce macrophage expression of genes involved in inflammation and cartilage degradation.Bone marrow derived macrophages were stimulated in vitro with 500 µg/ml of OCP crystals for 4 hours. RNA was extracted, reverse transcribed and qRT-PCR performed using gene specific primers with Tbp, and Gapdh as reference genes. Results are expressed as the fold induction of OCP treated over unstimulated macrophages, using the mean ± S.E.M of triplicate samples.
Mentions: In view of the predominant macrophage infiltrate within the synovium of OCP injected mice, we hypothesized that crystals induce the expression of macrophage genes that lead to cartilage damage. We stimulated bone marrow derived macrophages from mice with OCP crystals, and analysed by qRT-PCR the expression of inflammatory cytokine and matrix modifying genes (Figure 4).We found dramatically increased expression (>10x compared to control) of ADAMTS4, syndecan 1 (SDC1), MMP3 and 9, CXCL1 and CXCL2, as well as the cytokines ILA, IL1B, IL6 and TNFA. The alarmins S100A8 and A9 were also upregulated significantly (Figure 4).

Bottom Line: BCP crystal-induced synovitis was totally independent of IL-1α and IL-1β signalling and no alterations of inflammation were observed in mice deficient for components of the NLRP3-inflammasome, IL-1α or IL-1β.Similarly, treatment with anakinra did not prevent BCP crystal effects.The effects are independent of IL-1 and NLRP3 inflammasome.

View Article: PubMed Central - PubMed

Affiliation: INSERM, UMR-S 606, Hospital Lariboisière, Paris, France.

ABSTRACT

Background: basic calcium phosphate (BCP) crystals are commonly found in osteoarthritis (OA) and are associated with cartilage destruction. BCP crystals induce in vitro catabolic responses with the production of metalloproteases and inflammatory cytokines such as interleukin-1 (IL-1). In vivo, IL-1 production induced by BCP crystals is both dependant and independent of NLRP3 inflammasome. We aimed to clarify 1/ the role of BCP crystals in cartilage destruction and 2/ the role of IL-1 and NLRP3 inflammasome in cartilage degradation related to BCP crystals.

Methodology principal findings: synovial membranes isolated from OA knees were analysed by alizarin Red and FTIR. Pyrogen free BCP crystals were injected into right knees of WT, NLRP3 -/-, ASC -/-, IL-1α -/- and IL-1β-/- mice and PBS was injected into left knees. To assess the role of IL-1, WT mice were treated by intra-peritoneal injections of anakinra, the IL-1Ra recombinant protein, or PBS. Articular destruction was studied at d4, d17 and d30 assessing synovial inflammation, proteoglycan loss and chondrocyte apoptosis. BCP crystals were frequently found in OA synovial membranes including low grade OA. BCP crystals injected into murine knee joints provoked synovial inflammation characterized by synovial macrophage infiltration that persisted at day 30, cartilage degradation as evidenced by loss of proteoglycan staining by Safranin-O and concomitant expression of VDIPEN epitopes, and increased chondrocyte apoptosis. BCP crystal-induced synovitis was totally independent of IL-1α and IL-1β signalling and no alterations of inflammation were observed in mice deficient for components of the NLRP3-inflammasome, IL-1α or IL-1β. Similarly, treatment with anakinra did not prevent BCP crystal effects. In vitro, BCP crystals elicited enhanced transcription of matrix degrading and pro-inflammatory genes in macrophages.

Conclusions significance: intra-articular BCP crystals can elicit synovial inflammation and cartilage degradation suggesting that BCP crystals have a direct pathogenic role in OA. The effects are independent of IL-1 and NLRP3 inflammasome.

Show MeSH
Related in: MedlinePlus