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CD55 deposited on synovial collagen fibers protects from immune complex-mediated arthritis.

Karpus ON, Kiener HP, Niederreiter B, Yilmaz-Elis AS, van der Kaa J, Ramaglia V, Arens R, Smolen JS, Botto M, Tak PP, Verbeek JS, Hamann J - Arthritis Res. Ther. (2015)

Bottom Line: Abundant CD55 expression seen in FLS of the intimal lining layer was associated with linearly oriented reticular fibers and was resistant to phospholipase C treatment.Expression of CD55 colocalized with collagen type I and III as well as with complement C3.A comparable distribution of CD55 was established in three-dimensional micromasses after ≥3 weeks of culture together with the ECM.

View Article: PubMed Central - PubMed

Affiliation: Departments of Experimental Immunology, Internal Medicine, and Genetics, Room K0-140, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. o.karpus@amc.uva.nl.

ABSTRACT

Introduction: CD55, a glycosylphosphatidylinositol-anchored, complement-regulating protein (decay-accelerating factor), is expressed by fibroblast-like synoviocytes (FLS) with high local abundance in the intimal lining layer. We here explored the basis and consequences of this uncommon presence.

Methods: Synovial tissue, primary FLS cultures, and three-dimensional FLS micromasses were analyzed. CD55 expression was assessed by quantitative polymerase chain reaction (PCR), in situ hybridization, flow cytometry, and immunohistochemistry. Reticular fibers were visualized by Gomori staining and colocalization of CD55 with extracellular matrix (ECM) proteins by confocal microscopy. Membrane-bound CD55 was released from synovial tissue with phospholipase C. Functional consequences of CD55 expression were studied in the K/BxN serum transfer model of arthritis using mice that in addition to CD55 also lack FcγRIIB (CD32), increasing susceptibility for immune complex-mediated pathology.

Results: Abundant CD55 expression seen in FLS of the intimal lining layer was associated with linearly oriented reticular fibers and was resistant to phospholipase C treatment. Expression of CD55 colocalized with collagen type I and III as well as with complement C3. A comparable distribution of CD55 was established in three-dimensional micromasses after ≥3 weeks of culture together with the ECM. CD55 deficiency did not enhance K/BxN serum-induced arthritis, but further exaggerated disease activity in Fcgr2b (-/-) mice.

Conclusions: CD55 is produced by FLS and deposited on the local collagen fiber meshwork, where it protects the synovial tissue against immune complex-mediated arthritis.

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Expression pattern of CD55 coincides with collagenous structures in three-dimensional fibroblast-like synoviocytes (FLS) micromasses. (A, B, E, F) Sections of three-dimensional FLS micromasses were stained with anti-CD55 antibody at day 14 (A) and day 28 (E), and then processed to Gomori silver impregnation (B and F, respectively). (C, D, G, H) Sections of three-dimensional FLS micromasses, which were cultured with 10 ng/ml tumor necrosis factor (TNF), were stained with anti-CD55 antibody at day 14 (C) and day 28 (G), and then processed to Gomori silver impregnation (D and H, respectively). Red arrowheads indicate a similar distribution of CD55 and collagenous fibers. Shown are representative stainings derived by light microscopy; magnification 40 x.
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Fig3: Expression pattern of CD55 coincides with collagenous structures in three-dimensional fibroblast-like synoviocytes (FLS) micromasses. (A, B, E, F) Sections of three-dimensional FLS micromasses were stained with anti-CD55 antibody at day 14 (A) and day 28 (E), and then processed to Gomori silver impregnation (B and F, respectively). (C, D, G, H) Sections of three-dimensional FLS micromasses, which were cultured with 10 ng/ml tumor necrosis factor (TNF), were stained with anti-CD55 antibody at day 14 (C) and day 28 (G), and then processed to Gomori silver impregnation (D and H, respectively). Red arrowheads indicate a similar distribution of CD55 and collagenous fibers. Shown are representative stainings derived by light microscopy; magnification 40 x.

Mentions: Three-dimensional micromasses, grown from FLS, mimic phenotypic characteristics of the normal and the hyperplastic intimal lining layer [5]. When staining three-dimensional micromasses, we detected a CD55 signal after about 3 to 4 weeks of culture that was not visible at earlier time points (Figure 3A/E). As in synovial tissue, CD55 staining appeared as a fibrillar pattern within and at the basis of the intimal lining layer. Gomori silver staining of micromasses confirmed the development of reticular fibers within time (Figure 3B/F). Addition of TNF caused hyperplasia of the lining [5], coinciding with an intensified CD55 signal (Figure 3C/G) and more refined collagenous fibers visualized by Gomori silver staining and collagen III immunohistochemistry (Figure 3D/H and Figure S2 in Additional file 1). Thus, three-dimensional FLS micromasses develop over time the characteristic fibrillar CD55 expression pattern found in the intimal lining layer and, in parallel, a collagenous meshwork.Figure 3


CD55 deposited on synovial collagen fibers protects from immune complex-mediated arthritis.

Karpus ON, Kiener HP, Niederreiter B, Yilmaz-Elis AS, van der Kaa J, Ramaglia V, Arens R, Smolen JS, Botto M, Tak PP, Verbeek JS, Hamann J - Arthritis Res. Ther. (2015)

Expression pattern of CD55 coincides with collagenous structures in three-dimensional fibroblast-like synoviocytes (FLS) micromasses. (A, B, E, F) Sections of three-dimensional FLS micromasses were stained with anti-CD55 antibody at day 14 (A) and day 28 (E), and then processed to Gomori silver impregnation (B and F, respectively). (C, D, G, H) Sections of three-dimensional FLS micromasses, which were cultured with 10 ng/ml tumor necrosis factor (TNF), were stained with anti-CD55 antibody at day 14 (C) and day 28 (G), and then processed to Gomori silver impregnation (D and H, respectively). Red arrowheads indicate a similar distribution of CD55 and collagenous fibers. Shown are representative stainings derived by light microscopy; magnification 40 x.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4325944&req=5

Fig3: Expression pattern of CD55 coincides with collagenous structures in three-dimensional fibroblast-like synoviocytes (FLS) micromasses. (A, B, E, F) Sections of three-dimensional FLS micromasses were stained with anti-CD55 antibody at day 14 (A) and day 28 (E), and then processed to Gomori silver impregnation (B and F, respectively). (C, D, G, H) Sections of three-dimensional FLS micromasses, which were cultured with 10 ng/ml tumor necrosis factor (TNF), were stained with anti-CD55 antibody at day 14 (C) and day 28 (G), and then processed to Gomori silver impregnation (D and H, respectively). Red arrowheads indicate a similar distribution of CD55 and collagenous fibers. Shown are representative stainings derived by light microscopy; magnification 40 x.
Mentions: Three-dimensional micromasses, grown from FLS, mimic phenotypic characteristics of the normal and the hyperplastic intimal lining layer [5]. When staining three-dimensional micromasses, we detected a CD55 signal after about 3 to 4 weeks of culture that was not visible at earlier time points (Figure 3A/E). As in synovial tissue, CD55 staining appeared as a fibrillar pattern within and at the basis of the intimal lining layer. Gomori silver staining of micromasses confirmed the development of reticular fibers within time (Figure 3B/F). Addition of TNF caused hyperplasia of the lining [5], coinciding with an intensified CD55 signal (Figure 3C/G) and more refined collagenous fibers visualized by Gomori silver staining and collagen III immunohistochemistry (Figure 3D/H and Figure S2 in Additional file 1). Thus, three-dimensional FLS micromasses develop over time the characteristic fibrillar CD55 expression pattern found in the intimal lining layer and, in parallel, a collagenous meshwork.Figure 3

Bottom Line: Abundant CD55 expression seen in FLS of the intimal lining layer was associated with linearly oriented reticular fibers and was resistant to phospholipase C treatment.Expression of CD55 colocalized with collagen type I and III as well as with complement C3.A comparable distribution of CD55 was established in three-dimensional micromasses after ≥3 weeks of culture together with the ECM.

View Article: PubMed Central - PubMed

Affiliation: Departments of Experimental Immunology, Internal Medicine, and Genetics, Room K0-140, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. o.karpus@amc.uva.nl.

ABSTRACT

Introduction: CD55, a glycosylphosphatidylinositol-anchored, complement-regulating protein (decay-accelerating factor), is expressed by fibroblast-like synoviocytes (FLS) with high local abundance in the intimal lining layer. We here explored the basis and consequences of this uncommon presence.

Methods: Synovial tissue, primary FLS cultures, and three-dimensional FLS micromasses were analyzed. CD55 expression was assessed by quantitative polymerase chain reaction (PCR), in situ hybridization, flow cytometry, and immunohistochemistry. Reticular fibers were visualized by Gomori staining and colocalization of CD55 with extracellular matrix (ECM) proteins by confocal microscopy. Membrane-bound CD55 was released from synovial tissue with phospholipase C. Functional consequences of CD55 expression were studied in the K/BxN serum transfer model of arthritis using mice that in addition to CD55 also lack FcγRIIB (CD32), increasing susceptibility for immune complex-mediated pathology.

Results: Abundant CD55 expression seen in FLS of the intimal lining layer was associated with linearly oriented reticular fibers and was resistant to phospholipase C treatment. Expression of CD55 colocalized with collagen type I and III as well as with complement C3. A comparable distribution of CD55 was established in three-dimensional micromasses after ≥3 weeks of culture together with the ECM. CD55 deficiency did not enhance K/BxN serum-induced arthritis, but further exaggerated disease activity in Fcgr2b (-/-) mice.

Conclusions: CD55 is produced by FLS and deposited on the local collagen fiber meshwork, where it protects the synovial tissue against immune complex-mediated arthritis.

Show MeSH
Related in: MedlinePlus