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New Insights for RANKL as a Proinflammatory Modulator in Modeled Inflammatory Arthritis.

New Insights for RANKL as a Proinflammatory Modulator in Modeled Inflammatory Arthritis.

Authors :
Papadaki M
Rinotas V
Violitzi F
Thireou T
Panayotou G
Samiotaki M
Douni E
Source :
Frontiers in immunology [Front Immunol] 2019 Feb 05; Vol. 10, pp. 97. Date of Electronic Publication: 2019 Feb 05 (Print Publication: 2019).
Publication Year :
2019

Abstract

Receptor activator of nuclear factor-κB ligand (RANKL), a member of the Tumor Necrosis Factor (TNF) superfamily, constitutes the master regulator of osteoclast formation and bone resorption, whereas its involvement in inflammatory diseases remains unclear. Here, we used the human TNF transgenic mouse model of erosive inflammatory arthritis to determine if the progression of inflammation is affected by either genetic inactivation or overexpression of RANKL in transgenic mouse models. TNF-mediated inflammatory arthritis was significantly attenuated in the absence of functional RANKL. Notably, TNF overexpression could not compensate for RANKL-mediated osteopetrosis, but promoted osteoclastogenesis between the pannus and bone interface, suggesting RANKL-independent mechanisms of osteoclastogenesis in inflamed joints. On the other hand, simultaneous overexpression of RANKL and TNF in double transgenic mice accelerated disease onset and led to severe arthritis characterized by significantly elevated clinical and histological scores as shown by aggressive pannus formation, extended bone resorption, and massive accumulation of inflammatory cells, mainly of myeloid origin. RANKL and TNF cooperated not only in local bone loss identified in the inflamed calcaneous bone, but also systemically in distal femurs as shown by microCT analysis. Proteomic analysis in inflamed ankles from double transgenic mice overexpressing human TNF and RANKL showed an abundance of proteins involved in osteoclastogenesis, pro-inflammatory processes, gene expression regulation, and cell proliferation, while proteins participating in basic metabolic processes were downregulated compared to TNF and RANKL single transgenic mice. Collectively, these results suggest that RANKL modulates modeled inflammatory arthritis not only as a mediator of osteoclastogenesis and bone resorption but also as a disease modifier affecting inflammation and immune activation.

Details

Language :
English
ISSN :
1664-3224
Volume :
10
Database :
MEDLINE
Journal :
Frontiers in immunology
Publication Type :
Academic Journal
Accession number :
30804932
Full Text :
https://doi.org/10.3389/fimmu.2019.00097