Limits...
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.

Show MeSH

Related in: MedlinePlus

CD55 colocalizes with collagen I and collagen III, but not with ER-TR7 or CD90 in rheumatoid arthritis (RA) synovial tissue. Sections of RA synovial tissue were costained for CD55 (green) and (A) collagen I, (B) collagen III (C) CD90, or (D) ER-TR7 (all red, overlay yellow) and analyzed by confocal microscopy. Shown are representative stainings, magnification 63 x.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig4: CD55 colocalizes with collagen I and collagen III, but not with ER-TR7 or CD90 in rheumatoid arthritis (RA) synovial tissue. Sections of RA synovial tissue were costained for CD55 (green) and (A) collagen I, (B) collagen III (C) CD90, or (D) ER-TR7 (all red, overlay yellow) and analyzed by confocal microscopy. Shown are representative stainings, magnification 63 x.

Mentions: Silver impregnation techniques, like Gomori’s method, are widely used to detect reticular fibers. However, they have no biochemical definition and cannot be used as staining techniques for reticulin or different types of collagen [29]. We therefore performed immunofluorescent double staining of CD55 together with collagen I and III, CD90, and ER-TR7 on RA synovial tissue sections. We detected a clear colocalization of CD55 with collagen I and collagen III in the intimal lining layer, but not the vasculature, localized in the synovial sublining (Figure 4A/B and Figure S4A/C in Additional file 1). The latter was confirmed by costaining CD55 with CD90, a marker expressed by endothelial cells (Figure 4C).Figure 4


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)

CD55 colocalizes with collagen I and collagen III, but not with ER-TR7 or CD90 in rheumatoid arthritis (RA) synovial tissue. Sections of RA synovial tissue were costained for CD55 (green) and (A) collagen I, (B) collagen III (C) CD90, or (D) ER-TR7 (all red, overlay yellow) and analyzed by confocal microscopy. Shown are representative stainings, magnification 63 x.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig4: CD55 colocalizes with collagen I and collagen III, but not with ER-TR7 or CD90 in rheumatoid arthritis (RA) synovial tissue. Sections of RA synovial tissue were costained for CD55 (green) and (A) collagen I, (B) collagen III (C) CD90, or (D) ER-TR7 (all red, overlay yellow) and analyzed by confocal microscopy. Shown are representative stainings, magnification 63 x.
Mentions: Silver impregnation techniques, like Gomori’s method, are widely used to detect reticular fibers. However, they have no biochemical definition and cannot be used as staining techniques for reticulin or different types of collagen [29]. We therefore performed immunofluorescent double staining of CD55 together with collagen I and III, CD90, and ER-TR7 on RA synovial tissue sections. We detected a clear colocalization of CD55 with collagen I and collagen III in the intimal lining layer, but not the vasculature, localized in the synovial sublining (Figure 4A/B and Figure S4A/C in Additional file 1). The latter was confirmed by costaining CD55 with CD90, a marker expressed by endothelial cells (Figure 4C).Figure 4

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