RhoA Promotes Synovial Proliferation and Bone Erosion in Rheumatoid Arthritis through Wnt/PCP Pathway.

Ras homolog gene family member A (RhoA) plays a major role in the Wnt/planar cell polarity (PCP) pathway, which is significantly activated in patients with rheumatoid arthritis (RA). The function of RhoA in RA synovitis and bone erosion is still elusive. Here, we not only explored the impact of RhoA on the proliferation and invasion of RA fibroblast-like synoviocytes (FLSs) but also elucidated its effect on mouse osteoclast and a mouse model of collagen-induced arthritis (CIA). Results showed that RhoA was overexpressed in RA and CIA synovial tissues. Lentivirus-mediated silencing of RhoA increased apoptosis, attenuated invasion, and dramatically upregulated osteoprotegerin/receptor activator of nuclear factor-κB ligand (OPG/RANKL) ratio in RA-FLSs. Additionally, the silencing of RhoA inhibited mouse osteoclast differentiation in vitro and alleviated synovial hyperplasia and bone erosion in the CIA mouse model. These effects in RA-FLSs and osteoclasts were all regulated by RhoA/Rho-associated protein kinase 2 (ROCK2) and might interact with Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways.

Risk factors for the progression of rheumatoid arthritis-related interstitial lung disease: Clinical features, biomarkers, and treatment options.

OBJECTIVES: The clinical heterogeneity of the progression of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is high, and there is a lack of consensus on the clinical relevance and medical protocols. The purpose of this study is to explore the impact of clinical characteristics, new biomarkers and treatment options on the prognosis of RA-ILD patients and to explore whether these factors can predict the progression and death of these patients. METHODS: We retrospectively collected case data on RA-ILD patients who visited or were admitted to Changhai Hospital between October 2010 and September 2021. We followed up and finally included 75 patients. The main outcome indicator of disease progression was pulmonary functional impairment, which was assessed by changes of high-resolution computed tomography (HRCT) score or pulmonary function test before and after treatment. The demographics, clinical characteristics, laboratory tests, and treatment plans of RA-ILD patients in the progressive and stable groups were compared and analyzed. Clinically relevant variables were identified, and the incidence of pulmonary dysfunction and adverse events was recorded. Cox regression analysis was used to determine factors related to the progression of ILD. RESULTS: The mean age of RA-ILD onset was 64.0 years (SD 10.3), and 53 (70.7%) patients were female. Thirty-two (42.7%) patients had lung dysfunction, who were classified as the progressive group, and 13 (40.6%) of them died. In univariate analyses, male, smoking, high HRCT scores at baseline, RF-IgA>200 RU/ml, diffusing capacity of the lungs for carbon monoxide (DLCO), and usual interstitial pneumonia (UIP) pattern were significant risk factors for disease progression; while use of Leflunomide (LEF) was associated with better prognosis. The multivariate analysis revealed that RF-IgA>200 RU/ml (hazard ratio [HR] 3.17 [95% confidence interval (CI) 1.29, 7.81], P = 0.012), UIP pattern (HR 3.94 [95% CI 1.68, 9.26], P = 0.002), and male (HR 2.52 [95% CI 1.16, 5.46], P = 0.019) were significantly correlated with unfavorable outcomes in patients with RA-ILD. LEF (HR 0.25 [95% CI 0.10, 0.61], P = 0.002) was related to a better prognosis. However, it might be related to investigating medications changes after baseline. CONCLUSION: Our data suggests that male, UIP pattern, and increased RF-IgA may be potential predicting factors for poor prognosis of RA-ILD patients. We report a significant association between high titer of RF-IgA at baseline and RA-ILD progression for the first time, which might be a potentially important biomarker for the prognosis of RA-ILD.