Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: Anti citrullinated modified vimentin antibodies isolated from peripheral blood (PB) of RA patients induce osteoclasts (OC) formation from PB derived monocytes of healthy individuals. Recently dendritic cells have been proposed as potent precursor of osteoclasts. We aimed to characterize dendritic cells derived osteoclastogenesis in ACPA+ RA and to explore the effect of anti-CCP2 antibodies containing a large array of anti-citrulline specificities on dendritic cells mediated osteoclastogenesis.
Methods: SF (n=26) samples were collected from RA patients. Total IgG were isolated first on Protein G and than on CCP2 affinity columns. CD14+ monocytes were isolated from (PB) of ACPA+ RA patients and cultured in the presence of GM-CSF and IL-4 to generate dendritic cells (DC) or M-CSF to generate macrophages (MΦ). DC’s and MΦ were further differentiated to OC in the presence of RANKL and M-CSF, with or without ACPA IgG or flow through control IgG (at a final concentration of 100 ng/ml). OC were counted as multinucleated (more than 3 nuclei) TRAP+ cells. In parallel cultures were grown on osteoassay surfaces and resorbed area was quantified by computer assisted image analysis. Proteomic analysis and western blot to identify citrullinated proteins were performed on different stages of differentiation of dendritic cells derived osteoclasts.
Results: Osteoclastogenesis from DC was as efficient as osteoclastogenesis from MΦ of ACPA+ RA patients. ACPA IgG increased RANKL-driven osteoclastogenesis from both DC (from a median of 193 OC/well, interquartile variation of 86-308 in controls to a median of 418 OC/well, IQR 317-447) and MΦ (from a median of 238 OC/well, IQR 55.5-378.5 to a median of 333.5, IQR 88.8-489.3). These changes were paralleled by an increase of bone resorption areas by ACPA IgG in both the dendritic assay (from a median of 6.8%, IRQ 1.6-18.9 to a median of 10.3%, IQR 2.3-38.4) and the monocyte assay (from a median of 4.9%, IRQ 1.9-8.5 to a median of 6.9, IQR 2.7-10) No significant increase in either osteoclasts numbers or resorption areas was observed with the control flow through IgG. Interestingly when OC precursors were obtained from healthy donors, ACPA were only able to promote dendritic driven but not monocyte driven osteoclastogenesis. Similar to our previous findings in monocytes-derived osteoclasts we found a significant time dependent increase in native vimentin levels during dendritic-derived osteoclast maturation with identification of citrullinated vimentin peptides in the matured but not immature osteoclasts. Western Blotting using ACPA IgG also confirmed presence of citrullinated proteins in matured osteoclasts.
Conclusion: SF derived ACPA IgG with broad specificities enhance RANKL-driven osteoclastogenesis. While citrullinated vimentin is a potential target in mature osteoclasts, the exact contributions of each distinct ACPA specificities remains to be determined.
Disclosure:
A. Krishnamurthy,
None;
H. Wähämaa,
None;
V. Joshua,
None;
C. Cerqueira,
None;
E. Ossipova,
None;
N. Vivar Pomiano,
None;
K. Lundberg,
None;
V. Malmström,
None;
P. J. Jakobsson,
None;
L. Klareskog,
None;
G. Schett,
None;
J. Ytterberg,
None;
A. I. Catrina,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/osteoclastogenesis-is-enhanced-by-synovial-fluid-derived-anti-citrullinated-proteins-antibodies-in-rheumatoid-arthritis/