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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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Related in: MedlinePlus

CD55 is expressed in the intimal lining layer of rheumatoid arthritis (RA) synovial tissue. (A) Sections of RA synovial tissue were stained with a fluorescein isothiocyanate (FITC)-labeled CD55 antibody (clone IA10) and analyzed by confocal microscopy. Note the fibrillar appearance of the fluorescent signal; magnification 20 x. (B) RA synovial tissue sections were stained with a CD55 antibody (clone 143–30) and visualized by immunohistochemistry and light microscopy; magnification 20 x. (C)In situ hybridization, using an antisense locked nucleic acid (LNA) oligomer, detects CD55 transcripts primarily in the synovial lining. Representative images are shown; magnification 10 x.
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Fig1: CD55 is expressed in the intimal lining layer of rheumatoid arthritis (RA) synovial tissue. (A) Sections of RA synovial tissue were stained with a fluorescein isothiocyanate (FITC)-labeled CD55 antibody (clone IA10) and analyzed by confocal microscopy. Note the fibrillar appearance of the fluorescent signal; magnification 20 x. (B) RA synovial tissue sections were stained with a CD55 antibody (clone 143–30) and visualized by immunohistochemistry and light microscopy; magnification 20 x. (C)In situ hybridization, using an antisense locked nucleic acid (LNA) oligomer, detects CD55 transcripts primarily in the synovial lining. Representative images are shown; magnification 10 x.

Mentions: Immunofluorescence staining of RA synovial tissue revealed the characteristic, marked presence of CD55 in the intimal lining layer (Figure 1A). A strong staining was obtained with a FITC-labeled CD55 antibody without further signal amplification, closely matching results obtained with immunohistochemistry (Figure 1B). In situ hybridization with a CD55-specific antisense LNA oligomer generated a corresponding pattern, confirming that lining cells, previously identified as FLS [7], are the primary source of CD55 gene expression in synovial tissue (Figure 1C). The hybridization signal of CD55 in the synovial sublining was weaker, yet detectable, which fits its wide cellular distribution, including most immune cells [21].Figure 1


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 is expressed in the intimal lining layer of rheumatoid arthritis (RA) synovial tissue. (A) Sections of RA synovial tissue were stained with a fluorescein isothiocyanate (FITC)-labeled CD55 antibody (clone IA10) and analyzed by confocal microscopy. Note the fibrillar appearance of the fluorescent signal; magnification 20 x. (B) RA synovial tissue sections were stained with a CD55 antibody (clone 143–30) and visualized by immunohistochemistry and light microscopy; magnification 20 x. (C)In situ hybridization, using an antisense locked nucleic acid (LNA) oligomer, detects CD55 transcripts primarily in the synovial lining. Representative images are shown; magnification 10 x.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig1: CD55 is expressed in the intimal lining layer of rheumatoid arthritis (RA) synovial tissue. (A) Sections of RA synovial tissue were stained with a fluorescein isothiocyanate (FITC)-labeled CD55 antibody (clone IA10) and analyzed by confocal microscopy. Note the fibrillar appearance of the fluorescent signal; magnification 20 x. (B) RA synovial tissue sections were stained with a CD55 antibody (clone 143–30) and visualized by immunohistochemistry and light microscopy; magnification 20 x. (C)In situ hybridization, using an antisense locked nucleic acid (LNA) oligomer, detects CD55 transcripts primarily in the synovial lining. Representative images are shown; magnification 10 x.
Mentions: Immunofluorescence staining of RA synovial tissue revealed the characteristic, marked presence of CD55 in the intimal lining layer (Figure 1A). A strong staining was obtained with a FITC-labeled CD55 antibody without further signal amplification, closely matching results obtained with immunohistochemistry (Figure 1B). In situ hybridization with a CD55-specific antisense LNA oligomer generated a corresponding pattern, confirming that lining cells, previously identified as FLS [7], are the primary source of CD55 gene expression in synovial tissue (Figure 1C). The hybridization signal of CD55 in the synovial sublining was weaker, yet detectable, which fits its wide cellular distribution, including most immune cells [21].Figure 1

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