Genetic causal relationship between gut microbiome and psoriatic arthritis: a bidirectional two-sample Mendelian randomization study.

Background: Several observational studies have suggested a potential relationship between gut microbiome and psoriatic arthritis (PsA). However, the causality of this relationship still remains unclear. We aim to explore if the specific gut microbiome is causally associated with PsA at the genetic level and offer valuable insights into the etiology of PsA. Methods: In this study, we employed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal effects of the gut microbiome on PsA. Publicly accessible genome-wide association study summary data of gut microbiome were obtained from the MiBioGen consortium (n = 14,306), while the summary statistics of psoriatic arthropathies were sourced from the FinnGen consortium R8 release data (2,776 cases and 221,323 controls). The primary analytical method employed was inverse variance weighted (IVW), complemented by supplementary methods including MR-Egger, weighted median, weighted mode, maximum likelihood, MR-PRESSO, and cML-MA. Reverse MR analysis was performed on the bacteria that were found to be causally associated with PsA in forward MR analysis. Cochran's IVW Q statistic was utilized to assess the heterogeneity of instrumental variables among the selected single nucleotide polymorphisms. Results: IVW estimates revealed that Ruminococcaceae_UCG-002 (odds ratio (OR) = 0.792, 95% confidence interval (CI), 0.643-0.977, p = 0.029) exhibited a protective effect on PsA. Conversely, Blautia (OR = 1.362, 95% CI, 1.008-1.842, p = 0.044), Eubacterium_fissicatena_group (OR = 1.28, 95% CI, 1.075-1.524, p = 0.006), and Methanobrevibacter (OR = 1.31, 95% CI, 1.059-1.621, p = 0.013) showed a positive correlation with the risk of PsA. No significant heterogeneity, horizontal pleiotropy, or outliers were observed, and the results of the MR analysis remained unaffected by any single nucleotide polymorphisms. According to the results of reverse MR analysis, no significant causal effect of PsA was found on gut microbiome. Conclusion: This study establishes for the first time a causal relationship between the gut microbiome and PsA, providing potential valuable strategies for the prevention and treatment of PsA. Further randomized controlled trials are urgently warranted to support the targeted protective mechanisms of probiotics on PsA.

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.

Long non-coding RNA PANDAR promoted radiation and cisplatin-induced DNA damage repair through ATR/CHK1 in NSCLC.

BACKGROUND: DNA-damaging agents, including radiation and platinum-based chemotherapy, are indispensable treatments for non-small cell lung cancer (NSCLC) patients. However, cancer cells tend to be resistant to both radiation and chemotherapy, thus resulting in treatment failure or recurrence. The purpose of this study was to explore the effect and mechanism of long non-coding RNA (lncRNA) PANDAR (promoter of CDKN1A antisense DNA damage-activated RNA) on NSCLC sensitivity to radiation and chemotherapy. METHODS: Cell counting kit (CCK-8), colony formation and flow cytometry were respectively performed to determine the cell cycle and apoptosis of NSCLC cells treated with γ-ray radiation and cisplatin. The extent of DNA damage was evaluated using a comet assay and immunofluorescence staining against γH2AX. In addition, we explored the role of PANDAR in DNA damage response pathways through western blot analysis. Finally, a nude mouse subcutaneous xenograft model was established to assess the sensitivity to radiation and chemotherapy in vivo. RESULTS: In cell experiments, PANDAR knockdown can increase the sensitivity of NSCLC cells to radiation and cisplatin. The CCK-8 results showed that cell viability was significantly increased in the overexpression group after radiation and cisplatin treatments. The overexpression group also showed more colonies, less apoptosis and DNA damage, and G2/M phase arrest was aggravated to provide the time necessary for DNA repair. Contrary to PANDAR overexpression, the trends were reversed in the PANDAR knockdown group. Furthermore, PANDAR knockdown inhibited radiation and cisplatin-activated phosphorylation levels of ATR and CHK1 in NSCLC cells. Finally, our in vivo model showed that targeting PANDAR significantly sensitized NSCLC to radiation and cisplatin. CONCLUSION: Our study showed that PANDAR knockdown promoted sensitivity to radiation and cisplatin in NSCLC by regulating the ATR/CHK1 pathway, thus providing a novel understanding as well as a therapeutic target for NSCLC treatment. In NSCLC cells, lncRNA PANDAR negatively regulates sensitivity to radiation and cisplatin. PANDAR can promote the repair of radiation and cisplatin-induced DNA damage and activation of the G2/M checkpoint through the ATR/CHK1 pathway. PANDAR knockdown results in defects in DNA damage repair accompanied by more cell apoptosis.

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.