Impaired ATM Activation in B Cells Promotes Osteoclastogenic Cytokine Production and Bone Erosion in Patients with Rheumatoid Arthritis
Ontology highlight
ABSTRACT: Rheumatoid arthritis (RA) patients may display atypical CD21-/lo B cells in their blood but the significance of this observation remains unclear. We report here that the group of RA patients with elevated frequencies of CD21-/lo B cells shows decreased ataxia-telangiectasia mutated (ATM) expression and activation in B cells compared with other RA patients and healthy donor controls. In agreement with ATM involvement in the regulation of V(D)J recombination, RA patients with defective ATM function displayed a skewed B cell receptor (BCR) Igk repertoire, which resembled that of ataxia-telangiectasia (AT) patients. This repertoire was characterized by increased Jk1 and decreased upstream Vk gene segment usage, suggesting improper secondary recombination processes and selection. In addition, altered ATM function in B cells was associated with decreased osteoprotegerin (OPG) and increased RANKL production. These changes favor bone loss and correlated with a higher prevalence of erosive disease in RA patients with impaired ATM function. Using a humanized mouse model, we also show that ATM inhibition in vivo induces an altered Igk repertoire and RANKL production by immature B cells in the bone marrow, leading to decreased bone density. We conclude that dysregulated ATM function in B cells promotes bone erosion and the emergence of circulating CD21-/lo B cells, thereby contributing to RA pathophysiology.
ORGANISM(S): Homo sapiens
PROVIDER: GSE132832 | GEO | 2019/11/23
REPOSITORIES: GEO
ACCESS DATA