Objectives: We investigated the relationships among M1 monocytes, M2 monocytes, osteoclast (OC) differentiation ability, and clinical characteristics in patients with rheumatoid arthritis (RA). Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from RA patients and healthy donors, and we then investigated the number of M1 monocytes or M2 monocytes by fluorescence-activated cell sorting. We also obtained and cultured CD14-positive cells from PBMCs from RA patients and healthy donors to investigate OC differentiation in vitro. Results: Forty RA patients and 20 healthy donors were included. Twenty-two patients (55%) were anticitrullinated protein antibody (ACPA) positive. The median M1/M2 ratio was 0.59 (0.31–1.11, interquartile range). There were no significant differences between the RA patients and healthy donors. There was a positive correlation between the M1/M2 ratio and the differentiated OC number in vitro in RA patients (ρ = 0.81, p < 0.001). The ACPA-positive patients had significantly higher M1/M2 ratios in vivo (p = 0.028) and significantly greater numbers of OCs in vitro (p = 0.005) than the ACPA-negative patients. Multivariable regression analysis revealed that the M1/M2 ratio was the sole significant contribution factor to in vitro osteoclastogenesis. RA patients with M1/M2 ratios >1 (having relatively more M1 monocytes) had higher C-reactive protein and erythrocyte sedimentation rates than RA patients with M1/M2 ratios ≤1. M1-dominant monocytes in vitro produced higher concentrations of interleukin-6 upon stimulation with lipopolysaccharide than M2 monocytes. Conclusion: M1/M2 monocytes imbalance strongly contributes to osteoclastogenesis of RA patients. Our findings cast M1 and M2 monocyte subsets in a new light as a new target of treatments for RA to prevent progression of osteoclastic bone destruction.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint inflammation leading to joint destruction and deformity. The crucial role of osteoclasts in the bone erosion in RA has been demonstrated. Deregulated osteoclastogenesis which is affected by environmental factors including the inflammatory state, as well as genetic and epigenetic factors, is one of hallmarks of RA pathogenesis. An enhanced-monocyte-to-osteoclast transition plays an important role in osteoclast upregulation in RA because under specific stimuli, circulating monocytes might migrate to a specific location in the bones and fuse with each other to become mature multinucleated osteoclasts. To understand the mechanism of bone damage in RA and to develop novel treatments targeting osteoclast upregulation, it is important to clarify our understanding of the monocyte-to-osteoclast transition in RA. Several potential targets which inhibit both inflammation and osteoclastogenesis, as well as regulators that affect the monocyte-to-osteoclast transition have been revealed by recent studies. Here, we review the factors affecting osteoclastogenesis in RA, summarize the anti-osteoclastogenic effects of current RA treatments, and identify promising therapeutic targets relating to both inflammation and osteoclastogenesis.

Fibroblast-like synovial cells (FLS) have multilineage differentiation potential including osteoblasts. We aimed to investigate the role of microRNAs during the osteogenic differentiation of rheumatoid arthritis (RA)-FLS. RA-FLS were differentiated in osteogenic medium for 21 days. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) staining and Alizarin Red staining. MicroRNA (miRNA) array analysis was performed to investigate the differentially expressed miRNAs during osteogenic differentiation. Expression of miR-218-5p (miR-218) during the osteogenic differentiation was determined by quantitative real-time PCR. Transfections with an miR-218 precursor and inhibitor were used to confirm the targets of miR-218 and to analyze the ability of miR-218 to induce osteogenic differentiation. Secreted Dickkopf-1 (DKK1) from FLS transfected with miR-218 precursor/inhibitor or roundabout 1 (ROBO1) knockdown FLS established using ROBO1-small interfering RNA (siRNA) were measured by ELISA. The miRNA array revealed that 12 miRNAs were upregulated and 24 miRNAs were downregulated after osteogenic differentiation. We observed that the level of miR-218 rose in the early phase of osteogenic differentiation and then decreased. Pro-inflammatory cytokines modified the expression of miR-218. The induction of miR-218 in RA-FLS decreased ROBO1 expression, and promoted osteogenic differentiation. Both the overexpression of miR-218 and the knockdown of ROBO1 in RA-FLS decreased DKK1 secretion. We identified miR-218 as a crucial inducer of the osteogenic differentiation of RA-FLS. MiR-218 modulates the osteogenic differentiation of RA-FLS through the ROBO1/DKK-1 axis. The induction of the osteogenic differentiation of proliferating RA-FLS through the provision of miR-218 into RA-FLS or by boosting the cellular reservoir of miR-218 might thus become a therapeutic strategy for RA.

Objective: To compare the efficacy and safety of tofacitinib and baricitinib in patients with RA in a real-world setting.Methods: A total of 242 patients with RA who were treated with tofacitinib (n= 161) or baricitinib (n= 81) were enrolled. We evaluated efficacy and safety between tofacitinib and baricitinib using multivariable analyses to avoid confounding. Their clinical disease activity and AEs were evaluated for 24 weeks.Results: The mean (SD) DAS28-ESR change from baseline to 24 weeks was 1.57 (1.55) (tofacitinib) and 1.46 (1.36) (baricitinib). There was no significant difference in the clinical response between the two groups (adjusted mean difference, 0.04; 95% CI, −0.35 to 0.28). The efficacy was not significantly changed in the patients without concomitant MTX use in both groups, but the concomitant MTX use showed better clinical efficacy in the cases of baricitinib treatment. In both groups, the most common AE was herpes zoster infection, and the AE rates were similar between the two groups. However, the predictive factors contributing to clinical response as revealed by a multivariable logistic analysis differed. The concomitant oral steroid use was independently associated with the achievement of DAS-low disease activity in the tofacitinib group, whereas in the baricitinib group, the number of biological and/or targeted synthetic DMARDs previously used was associated.Conclusions: Our findings indicate that tofacitinib and baricitinib had comparable continuing efficacies and safety profiles. However, there is a possibility that the influence of clinical characteristics on the treatment response differs. The comparison provides useful information to the optimal use of JAK inhibitors in real-world settings.

To compare the incidence rates (IRs) of infectious diseases, major adverse cardiovascular events (MACEs), and malignancies in RA patients treated with tofacitinib, baricitinib or a TNF inhibitor. We retrospectively analyzed the cases of 499 RA patients treated with tofacitinib (n = 192), baricitinib (n = 104), or a TNF inhibitor (n = 203). We determined the IRs of infectious diseases and the standardized incidence ratio (SIR) of malignancies and investigated factors related to infectious diseases. After adjusting the clinical characteristic imbalance by propensity score weighting, we compared the incidence of adverse events between the JAK-inhibitor and TNF-inhibitor groups. Observational period: 961.9 patient-years (PY); median observational period: 1.3 years. The IRs in the JAK-inhibitor treatment were: serious infectious diseases other than herpes zoster (HZ), 8.36/100PY; HZ, 13.00/100PY. Multivariable Cox regression analyses revealed independent risk factors: the glucocorticoid dose in serious infectious diseases other than HZ and older age in HZ. Two MACEs and 11 malignancies were identified in JAK-inhibitor patients. The overall malignancy SIR was (non-significantly) higher compared with the general population (1.61/100PY, 95%CI: 0.80–2.88). The IR of HZ in JAK-inhibitor treatment was significantly higher, but there were no significant differences in other adverse events’ IRs between the JAK-inhibitor and TNF-inhibitor treatment, or between the two JAK inhibitors. The infectious disease IR in RA was comparable between tofacitinib and baricitinib, but the HZ rate was high compared with TNF inhibitors. The malignancy rate in JAK-inhibitor treatment was high but not significantly different from those of a general population and TNF-inhibitor users.

Purpose: Antisense oligonucleotides have been under investigation as potential therapeutics for many diseases, including inherited retinal diseases. Chemical modifications, such as chiral phosphorothioate (PS) backbone modification, are often used to improve stability and pharmacokinetic properties of these molecules. We aimed to generate a stereopure MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) antisense oligonucleotide as a tool to assess the impact stereochemistry has on potency, efficacy, and durability of oligonucleotide activity when delivered by intravitreal injection to eye. Methods: We generated a stereopure oligonucleotide (MALAT1-200) and assessed the potency, efficacy, and durability of its MALAT1 RNA-depleting activity compared with a stereorandom mixture, MALAT1-181, and other controls in in vitro assays, in vivo mouse and nonhuman primate (NHP) eyes, and ex vivo human retina cultures. Results: The activity of the stereopure oligonucleotide is superior to its stereorandom mixture counterpart with the same sequence and chemical modification pattern in in vitro assays, in vivo mouse and NHP eyes, and ex vivo human retina cultures. Findings in NHPs showed durable activity of the stereopure oligonucleotide in the retina, with nearly 95% reduction of MALAT1 RNA maintained for 4 months postinjection. Conclusions: An optimized, stereopure antisense oligonucleotide shows enhanced potency, efficacy, and durability of MALAT1 RNA depletion in the eye compared with its stereorandom counterpart in multiple preclinical models. Translational Relevance: As novel therapeutics, stereopure oligonucleotides have the potential to enable infrequent administration and low-dose regimens for patients with genetic diseases of the eye.