Exosomes and exosomal miRNAs: A new avenue for the future treatment of rheumatoid arthritis

Rheumatoid arthritis is a chronic systemic autoimmune disease that involves mainly synovitis and joint injury and is one of the main causes of disability. The pathogenesis of rheumatoid arthritis is complicated, and the treatment cycle is long. The traditional methods of inhibiting inflammation and immunosuppression are no longer sufficient for treatment of the disease, so there is an urgent need to seek new treatments. The exocrine microenvironment is a kind of microvesicle with a lipid bilayer membrane structure that can be secreted by most cells in the body. This structure contains cell-specific proteins, lipids and nucleic acids that can transmit this information from one cell to another. To achieve cell-to-cell communication. Exocrine microRNAs can be contained in exocrine cells and can be selectively transferred to target receptor cells via exocrine signaling, thus regulating the physiological function of target cells. This article focuses on the pathological changes that occur during the development of rheumatoid arthritis and the biological regulation of exocrine and exocrine microRNAs in rheumatoid joints. Research on the roles of exocrine and exocrine microRNAs in regulating the inflammatory response, cell proliferation/apoptosis, autophagy, effects on fibroblast-like synoviocytes and immune regulation in rheumatoid arthritis was reviewed. In addition, the challenges faced by this new treatment are discussed.

Recent progress in therapeutic strategies and biomimetic nanomedicines for rheumatoid arthritis treatment

INTRODUCTION

Rheumatoid arthritis (RA) is an autoimmune systemic disease in which inflammatory and immune cells accumulate in inflamed joints. Researchers aimed at the characteristics of RA to achieve the effect of treating RA through different therapeutic strategies, and have used various endogenous materials to design drug-loaded nanoparticles that can target RA by binding to cell adhesion molecules or chemokines. In some cases, the nanoparticles can respond to the characteristics of the microenvironment.

AREAS COVERED

This article reviews the recent advances in the treatment of RA from two aspects of therapeutic strategies and delivery strategies. Therapeutic strategies mainly include neutralization of inflammatory factors, promotion of inflammatory cell apoptosis, ROS scavenger, immunosuppression, and bone tissue repair. The drug delivery strategy is mainly described from two aspects: chemically functionalized biomimetic nanoparticles and endogenous nanoparticles.

EXPERT OPINION

Biomimetic NPs may be effective drug carriers for targeted RA treatment. NPs can reduce the clearance of mononuclear phagocytes, prolong the blood circulation time, and improve the targeting ability. With the deepening of research, more and more biomimetic NPs have entered the clinical trial stage. However, safe and scalable preparation methods are needed to improve their clinical applicability.

Licochalcone A activates Keap1-Nrf2 signaling to suppress arthritis via phosphorylation of p62 at serine 349

Licochalcone A (LCA) is derived from glycyrrhizae radix with antimicrobial, antitumor and anti-inflammatory activities. However, the anti-arthritic function of LCA and underlying mechanism has not been yet explored. The current study investigated the anti-arthritic effect of LCA and elucidated the underlying mechanism. The results showed that LCA significantly suppressed arthritis via the activation of SQSTM1 (p62)/nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling in the collagen-induced arthritis (CIA) model of DBA mice. In coincided with the results, this anti-arthritic effect of LCA was remarkably diminished in the collagen antibody-induced arthritis (CAIA) model of Nrf2-/- mice. These findings indicate that p62/Nrf2 signaling is a crucial pathway for the induction and treatment of arthritis. To further validate the effect of LCA on the arthritis, rheumatoid arthritis synovial fibroblasts (RASFs) isolated from the synovium of RA patients were employed in the study. In coincided with in vivo results, LCA inhibited the cell proliferation and arrested the cell cycle, induced apoptosis, suppressed pro-inflammatory cytokine secretion and increased expression of antioxidant enzymes via the activation of Keap1-Nrf2 signaling by enhancing p62 phosphorylation and expression, Nrf2 accumulation and Nrf2 nucleus translocation. Findings in the current study provide evidence that p62-Keap1-Nrf2 axis is a pivotal signaling pathway in development of arthritis and therapeutic efficacy of drugs, and LCA activates of Keap1-Nrf2 signaling to suppress arthritis by phosphorylation of p62 at Ser349. Collectively, LCA is valuable to be further investigated as a lead compound for application in anti-arthritis, and interference with the interaction between Nrf2 and Keap1 by phosphorylation of p62 may be a promising strategy for the discovery of anti-arthritic agents.

Patterns of interstitial lung disease and mortality in rheumatoid arthritis

Objective

To characterize a cohort of patients with RA who have interstitial lung disease (ILD) and to assess the utility of previously developed mortality staging systems [gender, age, lung physiology (GAP) and ILD-GAP].

Methods

All patients with RA and ILD seen at the Mayo Clinic from 1998 to 2014 were identified and manually screened for study inclusion. RA disease characteristics and pulmonary findings including high-resolution CT and pulmonary function testing were evaluated. Survival was estimated using Kaplan-Meier methods. GAP and ILD-GAP models were evaluated using c-statistics and standardized incidence ratios.

Results

The study included 181 patients with RA-associated ILD (96% Caucasian; 48% females; 37% never-smokers). The mean age at ILD diagnosis was 67.4 years ( s . d . 9.9). The median time from RA diagnosis to ILD was 4.9 years (range -10.9-48.1). The median follow-up was 3.1 years (range 0.01-14.8). Age, RA disease duration and low initial diffusing capacity for carbon monoxide were predictive of premature mortality in multivariate modelling. Sex, smoking status, obstructive lung disease, seropositivity and erosive disease were not associated with mortality. The 5-year survival rate was 59.7% (95% CI 51.5, 69.2). Survival did not differ between usual interstitial pneumonia, non-specific interstitial pneumonia and organizing pneumonia ( P = 0.42). The GAP model performed well in this cohort for both discrimination and calibration (c-statistic 0.71, standardized incidence ratio 0.97).

Conclusion

In this large single-centre cohort of patients with RA-ILD, most patients were seropositive and had a history of smoking. ILD most commonly occurred after the RA diagnosis. Mortality was high and did not differ among the types. The GAP model may be useful in assessing mortality risk.

Opioid use in patients with rheumatoid arthritis 2005-2014: a population-based comparative study

Opioid prescriptions have seen an increase across the USA, Canada, Europe, and the UK. In the USA, they have quadrupled from 1999 to 2010. Opioid use among patients with rheumatoid arthritis (RA) over time is not well described. This study examined trends of opioid use in patients with RA. Retrospective prescription data was examined from 2005 to 2014 in a population-based incidence cohort of patients with RA by 1987 ACR criteria and comparable non-RA subjects. Differences in opioid use were examined with Poisson models. A total of 501 patients with RA (71 % female) and 532 non-RA subjects (70 % female) were included in the study. Total and chronic opioid use in 2014 was substantial in both cohorts 40 % RA vs 24 % non-RA and 12 % RA vs. 4 % non-RA, respectively. Opioid use increased by 19 % per year in both cohorts during the study period (95 % confidence interval [CI] 1.15, 1.25). Relative risk (RR) of chronic opiate use for RA patients compared to non-RA subjects was highest in adults aged 50-64 years (RR 2.82; 95 % CI 1.43-6.23). RA disease characteristics, biologic use at index, treated depression/fibromyalgia, education, and smoking status were not significantly associated with chronic opiate use. Over a third of patients with RA use opioids in some form, and in more than a tenth use is chronic. Use has increased in recent years. Patients aged 50-64 with RA use substantially more opioids than their non-RA counterparts.