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Gottron's papules exhibit dermal accumulation of CD44 variant 7 (CD44v7) and its binding partner osteopontin: a unique molecular signature.

Kim JS, Bashir MM, Werth VP - J. Invest. Dermatol. (2012)

Bottom Line: Mechanically stretching cultured fibroblasts for 6 hours induced CD44v7 mRNA and protein, whereas IFN-γ treatment induced OPN mRNA and protein.OPN alone did not induce CD44v7, but stretching dermal fibroblasts in the presence of OPN increased human acute monocytic leukemia cell line (THP-1) monocyte binding, which is blunted by anti-CD44v7 blocking antibody.C4S, CD44v7, and OPN are three molecules uniquely present in Gottron's papules that contribute to inflammation individually and in association with one another.

View Article: PubMed Central - PubMed

Affiliation: New York University School of Medicine, New York, New York, USA.

ABSTRACT
The accumulated mucin in non-Gottron's dermatomyositis (DM) lesions is primarily chondroitin-4-sulfate (C4S), which is immunomodulatory in vitro. Gottron's papules are a particularly resistant manifestation of DM that often persist after other lesions have resolved with therapy. We examined non-Gottron's DM lesions and Gottron's papule skin biopsies for C4S, CD44 variant 7 (CD44v7), a chondroitin sulfate-binding isoform causally implicated in autoimmunity, and osteopontin (OPN), a CD44v7 ligand implicated in chronic inflammation. Gottron's papule dermis contained more C4S and CD44v7 than non-Gottron's lesions. Normal skin showed less CD44v7 over joints relative to Gottron's lesions. All DM dermis had increased OPN compared with healthy skin. Mechanically stretching cultured fibroblasts for 6 hours induced CD44v7 mRNA and protein, whereas IFN-γ treatment induced OPN mRNA and protein. OPN alone did not induce CD44v7, but stretching dermal fibroblasts in the presence of OPN increased human acute monocytic leukemia cell line (THP-1) monocyte binding, which is blunted by anti-CD44v7 blocking antibody. C4S, CD44v7, and OPN are three molecules uniquely present in Gottron's papules that contribute to inflammation individually and in association with one another. We propose that stretch-induced CD44v7 over joints, in concert with dysregulated OPN levels in the skin of DM patients, increases local inflammatory cell recruitment and contributes to the pathogenesis and resistance of Gottron's papules.

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Interferon-γ, but not interferon-α or interleukin-1α, induces osteopontin in cultured dermal fibroblastsConfluent cultured human dermal fibroblasts were incubated for 6h in control medium or in medium supplemented with IFNγ (10ng/mL), IFNα (100U/ml), or IL-1α (20ng/ml), after which RNA or conditioned media for ELISA were harvested; data from representative experiments are displayed. a. Osteopontin (OPN) mRNA levels were assayed by qRT-PCR, normalized to PPIA mRNA levels, and expressed relative to control; points denote mean OPN/PPIA mRNA for each well (sampled in triplicate), wide and short horizontal bars represent mean and SEM of triplicate conditions, respectively. P<0.0001 by ANOVA (***, P<0.001; n.s., not significant); b. Osteopontin protein in control and conditioned media was quantitated by ELISA; mean osteopontin protein detected (ng/ml) is indicated, horizontal bar represents SEM of triplicate conditions. P=0.0003 by ANOVA; (***, P<0.001; n.s., not significant).
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Figure 5: Interferon-γ, but not interferon-α or interleukin-1α, induces osteopontin in cultured dermal fibroblastsConfluent cultured human dermal fibroblasts were incubated for 6h in control medium or in medium supplemented with IFNγ (10ng/mL), IFNα (100U/ml), or IL-1α (20ng/ml), after which RNA or conditioned media for ELISA were harvested; data from representative experiments are displayed. a. Osteopontin (OPN) mRNA levels were assayed by qRT-PCR, normalized to PPIA mRNA levels, and expressed relative to control; points denote mean OPN/PPIA mRNA for each well (sampled in triplicate), wide and short horizontal bars represent mean and SEM of triplicate conditions, respectively. P<0.0001 by ANOVA (***, P<0.001; n.s., not significant); b. Osteopontin protein in control and conditioned media was quantitated by ELISA; mean osteopontin protein detected (ng/ml) is indicated, horizontal bar represents SEM of triplicate conditions. P=0.0003 by ANOVA; (***, P<0.001; n.s., not significant).

Mentions: Interferon-γ has been reported to stimulate osteopontin expression in monocytes (Li et al., 2003), but this induction has not been studied in dermal fibroblasts. Because interferon-γ is present in the skin of DM patients (Caproni et al., 2005; Wenzel et al., 2005) and mutations in the interferon-γ pathway have been associated with DM (Chinoy et al., 2007), we hypothesized a role for interferon-γ in the dysregulation of osteopontin expression in the skin. Treatment of human primary dermal fibroblasts with interferon-γ (10ng/mL) induced a 4.4-fold mean OPN mRNA expression compared to untreated control cells in vitro (p<0.001) (Figure 5a). Interferon-γ (10ng/mL) induced an 8.1-fold increase in OPN protein in fibroblast supernatant (p<0.001) (Figure 5b). Osteopontin mRNA and protein in the fibroblast supernatant were not induced by the pro-inflammatory cytokines IL-1α or interferon-α, indicating specificity (Figure 5a, 5b). Neither interferon-γ nor osteopontin treatment had a significant effect on fibroblast CD44v7 mRNA expression (data not shown).


Gottron's papules exhibit dermal accumulation of CD44 variant 7 (CD44v7) and its binding partner osteopontin: a unique molecular signature.

Kim JS, Bashir MM, Werth VP - J. Invest. Dermatol. (2012)

Interferon-γ, but not interferon-α or interleukin-1α, induces osteopontin in cultured dermal fibroblastsConfluent cultured human dermal fibroblasts were incubated for 6h in control medium or in medium supplemented with IFNγ (10ng/mL), IFNα (100U/ml), or IL-1α (20ng/ml), after which RNA or conditioned media for ELISA were harvested; data from representative experiments are displayed. a. Osteopontin (OPN) mRNA levels were assayed by qRT-PCR, normalized to PPIA mRNA levels, and expressed relative to control; points denote mean OPN/PPIA mRNA for each well (sampled in triplicate), wide and short horizontal bars represent mean and SEM of triplicate conditions, respectively. P<0.0001 by ANOVA (***, P<0.001; n.s., not significant); b. Osteopontin protein in control and conditioned media was quantitated by ELISA; mean osteopontin protein detected (ng/ml) is indicated, horizontal bar represents SEM of triplicate conditions. P=0.0003 by ANOVA; (***, P<0.001; n.s., not significant).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3375388&req=5

Figure 5: Interferon-γ, but not interferon-α or interleukin-1α, induces osteopontin in cultured dermal fibroblastsConfluent cultured human dermal fibroblasts were incubated for 6h in control medium or in medium supplemented with IFNγ (10ng/mL), IFNα (100U/ml), or IL-1α (20ng/ml), after which RNA or conditioned media for ELISA were harvested; data from representative experiments are displayed. a. Osteopontin (OPN) mRNA levels were assayed by qRT-PCR, normalized to PPIA mRNA levels, and expressed relative to control; points denote mean OPN/PPIA mRNA for each well (sampled in triplicate), wide and short horizontal bars represent mean and SEM of triplicate conditions, respectively. P<0.0001 by ANOVA (***, P<0.001; n.s., not significant); b. Osteopontin protein in control and conditioned media was quantitated by ELISA; mean osteopontin protein detected (ng/ml) is indicated, horizontal bar represents SEM of triplicate conditions. P=0.0003 by ANOVA; (***, P<0.001; n.s., not significant).
Mentions: Interferon-γ has been reported to stimulate osteopontin expression in monocytes (Li et al., 2003), but this induction has not been studied in dermal fibroblasts. Because interferon-γ is present in the skin of DM patients (Caproni et al., 2005; Wenzel et al., 2005) and mutations in the interferon-γ pathway have been associated with DM (Chinoy et al., 2007), we hypothesized a role for interferon-γ in the dysregulation of osteopontin expression in the skin. Treatment of human primary dermal fibroblasts with interferon-γ (10ng/mL) induced a 4.4-fold mean OPN mRNA expression compared to untreated control cells in vitro (p<0.001) (Figure 5a). Interferon-γ (10ng/mL) induced an 8.1-fold increase in OPN protein in fibroblast supernatant (p<0.001) (Figure 5b). Osteopontin mRNA and protein in the fibroblast supernatant were not induced by the pro-inflammatory cytokines IL-1α or interferon-α, indicating specificity (Figure 5a, 5b). Neither interferon-γ nor osteopontin treatment had a significant effect on fibroblast CD44v7 mRNA expression (data not shown).

Bottom Line: Mechanically stretching cultured fibroblasts for 6 hours induced CD44v7 mRNA and protein, whereas IFN-γ treatment induced OPN mRNA and protein.OPN alone did not induce CD44v7, but stretching dermal fibroblasts in the presence of OPN increased human acute monocytic leukemia cell line (THP-1) monocyte binding, which is blunted by anti-CD44v7 blocking antibody.C4S, CD44v7, and OPN are three molecules uniquely present in Gottron's papules that contribute to inflammation individually and in association with one another.

View Article: PubMed Central - PubMed

Affiliation: New York University School of Medicine, New York, New York, USA.

ABSTRACT
The accumulated mucin in non-Gottron's dermatomyositis (DM) lesions is primarily chondroitin-4-sulfate (C4S), which is immunomodulatory in vitro. Gottron's papules are a particularly resistant manifestation of DM that often persist after other lesions have resolved with therapy. We examined non-Gottron's DM lesions and Gottron's papule skin biopsies for C4S, CD44 variant 7 (CD44v7), a chondroitin sulfate-binding isoform causally implicated in autoimmunity, and osteopontin (OPN), a CD44v7 ligand implicated in chronic inflammation. Gottron's papule dermis contained more C4S and CD44v7 than non-Gottron's lesions. Normal skin showed less CD44v7 over joints relative to Gottron's lesions. All DM dermis had increased OPN compared with healthy skin. Mechanically stretching cultured fibroblasts for 6 hours induced CD44v7 mRNA and protein, whereas IFN-γ treatment induced OPN mRNA and protein. OPN alone did not induce CD44v7, but stretching dermal fibroblasts in the presence of OPN increased human acute monocytic leukemia cell line (THP-1) monocyte binding, which is blunted by anti-CD44v7 blocking antibody. C4S, CD44v7, and OPN are three molecules uniquely present in Gottron's papules that contribute to inflammation individually and in association with one another. We propose that stretch-induced CD44v7 over joints, in concert with dysregulated OPN levels in the skin of DM patients, increases local inflammatory cell recruitment and contributes to the pathogenesis and resistance of Gottron's papules.

Show MeSH
Related in: MedlinePlus