The advances of methotrexate resistance in rheumatoid arthritis

Synthesized pyrrole ester ameliorates adjuvant‑induced arthritis in Wistar rats by alleviating inflammation and downregulating the pro‑inflammatory cytokines

Piperine is an amide alkaloid responsible for producing the pungent smell that comes from black pepper. Piperine has been explained to exhibit significant properties such as anti-rheumatic, anti-inflammatory, and antihypertensive effects. The aim of the study was to synthesize pyrrole ester from piperine and evaluate its anti-arthritis effects in adjuvant-induced arthritis female Wistar rats. In this study, pyrrole ester (AU-5) was designed, synthesized and evaluated for ant-arthritic activity in adjuvant-induced arthritis Wistar rats. The synthesized pyrrole ester (AU-5) was administered in three selected doses (20, 10 and 5 mg/kg) to the arthritic-induced model. The administered ester significantly inhibited the increase in arthritis index, paw and ankle joint swelling compared to the arthritic control group. Similarly, the treated rats exhibited a remarkable increase in body weight increase, improved haematological, biochemical, histopathological and radiological parameters. Moreover, the excess production of rheumatoid factor (RF), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) was noticeably attenuated in all AU-5-treated rats. However, the spleen index, tumour necrosis factor (TNF-α) and interleukin-6 (IL-6) were distinctly lowered compared to arthritic control rats. Moreover, AU-5 showed promising liver protection by lowering the level of liver function markers Serum glutamic pyruvic transaminase (SGPT), Serum glutamic-oxaloacetic transaminase (SGOT) and alkaline phosphatase (ALP) in serum. Henceforth, it might be concluded that AU-5 has an anti-arthritic effect which can be credited to the down regulation of inflammatory markers and the pro-inflammatory cytokines.

Nanotechnology-empowered combination therapy for rheumatoid arthritis: principles, strategies, and challenges

Rheumatoid arthritis (RA) is an autoimmune disease with multifactorial etiology and intricate pathogenesis. In RA, repeated monotherapy is frequently associated with inadequate efficacy, drug resistance, and severe side effects. Therefore, a shift has occurred in clinical practice toward combination therapy. However, conventional combination therapy encounters several hindrances, including low selectivity to arthritic joints, short half-lives, and varying pharmacokinetics among coupled drugs. Emerging nanotechnology offers an incomparable opportunity for developing advanced combination therapy against RA. First, it allows for co-delivering multiple drugs with augmented physicochemical properties, targeted delivery capabilities, and controlled release profiles. Second, it enables therapeutic nanomaterials development, thereby expanding combination regimens to include multifunctional nanomedicines. Lastly, it facilitates the construction of all-in-one nanoplatforms assembled with multiple modalities, such as phototherapy, sonodynamic therapy, and imaging. Thus, nanotechnology offers a promising solution to the current bottleneck in both RA treatment and diagnosis. This review summarizes the rationale, advantages, and recent advances in nano-empowered combination therapy for RA. It also discusses safety considerations, drug-drug interactions, and the potential for clinical translation. Additionally, it provides design tips and an outlook on future developments in nano-empowered combination therapy. The objective of this review is to achieve a comprehensive understanding of the mechanisms underlying combination therapy for RA and unlock the maximum potential of nanotechnology, thereby facilitating the smooth transition of research findings from the laboratory to clinical practice.

Proteomics analyses of human plasma reveal triosephosphate isomerase as a potential blood marker of methotrexate resistance in rheumatoid arthritis

OBJECTIVE

The objective of this study was to assess differentially expressed blood proteins between patients with active RA and patients in remission after MTX treatment, with the aim of identifying a biomarker of MTX resistance (MTXR).

METHODS

Two populations of RA patients treated with a stable dose of s.c. MTX for at least 3 months were constituted according to the DAS28: remission (DAS28 < 2.6; n = 24) and active disease (DAS28 > 3.2; n = 32). The two groups of RA patients were homogeneous regarding their epidemiological characteristics, except for the duration of treatment, which was longer in the remission group. After collection of a blood sample, plasma protein digestion was performed, followed by untargeted proteomics analysis. Then, a targeted analysis was performed to confirm the results of the untargeted approach.

RESULTS

Untargeted proteomics analysis revealed eight plasma proteins that were differentially expressed between the two groups of patients. Among them, triosephosphate isomerase (TPI-1) and glucose-6-phosphate isomerase (GPI), which are main actors in glycolysis, were found down-regulated in the active group. This result was confirmed for TPI-1 in the targeted proteomics analysis.

CONCLUSION

A first step was achieved in the search for biomarkers of MTXR, with the identification of two actors in glycolysis (TPI-1 and GPI). The next step will be to confirm these results in a larger cohort, including samples from treatment-naive patients, to assess the predictive potential of these protein markers.

Efficacy of adalimumab combined with Tripterygium wilfordii Hook F in the treatment of patient with rheumatoid arthritis: A multicenter, open-label, randomized-controlled trial

OBJECTIVES

To evaluate the efficacy and safety of adalimumab (ADA) combined with Tripterygium wilfordii Hook F (TwHF) in the treatment of methotrexate (MTX)-inadequate response patients with rheumatoid arthritis (RA).

METHODS

In this multicenter, open-label, randomized controlled clinical trial, 64 RA patients with inadequate response to MTX were 1:1 randomly assigned into treatment or control groups. The treatment group was treated with ADA in combination with TwHF, and the control group was treated with ADA in combination with MTX for 24 weeks. The primary endpoint was the percentage of patients having low disease activity (2.6 ≤ DAS28-ESR < 3.2) and remission rates (DAS28-ESR < 2.6) at week 24.

RESULTS

In total, 53 of the 64 patients (82.8%) completed this 24-week clinical trial. By intent-to-treat (ITT) analysis, a comparable outcome was observed between the two groups. The percentage of patients achieving low disease activity in the treatment group and control group were 43.8% and 46.9% (95% CI, 21.28 to 27.48, p = .802). Percentage of patients achieving low disease activity rates were respectively 28.1% and 31.3% in the treatment group and control group (95% CI, 19.18 to 25.58, p = .784). In per-protocol (PP) analysis, the results were consistent with the ITT model. The incidence of adverse events was comparable between the two groups.

CONCLUSIONS

There were no significant differences in efficacy and safety between ADA combined with TwHF versus ADA combined with MTX in the treatment of RA. TwHF might be an alternative treatment for RA patients who are intolerant to MTX.

A pH-Responsive DNA Tetrahedron/Methotrexate Drug Delivery System Used for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is a chronic autoimmune disorder that leads to progressive and aggressive joint inflammation. The disease process is characterized by the activation of macrophages, which then release tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), accelerating tissue damage. Tackling tissue damage is a crucial target in the treatment of RA. In this study, a macrophage-targeted and pH-response DNA tetrahedron/methotrexate drug delivery system was constructed by loading methotrexate (MTX) onto a DNA duplex. MTX was used as a drug model, and a pH-response DNA tetrahedron (TET) was used as the drug carrier, which was modified with hyaluronic acid (HA) to target macrophages. The aim of this study was to evaluate the potential of TET as an effective drug carrier for the treatment of RA. On this basis, we successfully prepared TETs loaded with MTX, and in vitro assays showed that the MTX-TET treatment could successfully target macrophages and induce macrophages to polarize to M1 phenotype. At the same time, we also injected MTX-TET intravenously into collagen-induced arthritis (CIA) model mice, and the redness and swelling of the paws of mice were significantly alleviated, proving that the MTX-TET could successfully target inflamed joints and release MTX to treat joint swelling. In addition, the histochemical results showed that the MTX-TET could reduce synovitis and joint swelling in CIA mice, reduce the level of inflammatory factors in vivo, and improve the disease status while maintaining a good biosafety profile. This study showed that the MTX-TET treatment has beneficial therapeutic effects on RA, providing a new strategy for the clinical treatment of RA.

Intra-articular delivery system of methotrexate for rheumatoid arthritis therapy: An in-suit thermosensitive comprehensive gel of polysaccharide from Aconitum carmichaelii Debx

The polysaccharides (FP) extracted from the lateral roots of Aconitum carmichaelii Debx. (Fuzi) are natural compounds, which have effective therapy for rheumatoid arthritis (RA). Methotrexate (MTX) is the first-line drug for RA, but its application is greatly limited to the toxicity in liver and kidney and drug resistance. In this study, an attempt is made to apply oxidized FP (OFP) as a polymer carrier based on intra-articular delivery system loaded MTX. The FP could be developed and used as comprehensive gel carriers with biocompatibility and degradability for therapy of RA. Firstly, OFP-chitosan-poloxamer 407 (OFP-CS-F407-MTX) gel was prepared by natural non-toxic cross-linking agents. Physicochemical characterization was performed by using ¹H NMR and FTIR spectroscopic techniques to assess the successful functionalization of OFP. TGA, SEM and rheological experiment of OFP-CS-F407-MTX gel were investigated. Notably, we loaded MTX into OFP-CS-F407-MTX gel which had remarkable therapeutic efficacy and biosafety for RA. Based on advantages of intra-articular injection of OFP-CS-F407-MTX gel releasing MTX, it modulated proinflammatory cytokines by down-regulating TNF-α, IL-6 and IL-1β expression. Therefore, OFP-CS-F407-MTX in situ gel delivery system can potentially reduce systemic toxicity and irritation of oral administration of MTX but give a controlled release of drug for a long period of time.

Osthole regulates N6-methyladenosine-modified TGM2 to inhibit the progression of rheumatoid arthritis and associated interstitial lung disease

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease, and RA interstitial lung disease (ILD) is a severe complication of RA. This investigation aims to determine the effect and underlying mechanism of osthole (OS), which could be extracted from Cnidium, Angelica, and Citrus plants and evaluate the role of transglutaminase 2 (TGM2) in RA and RA-ILD. In this work, OS downregulated TGM2 to exert its additive effect with methotrexate and suppress the proliferation, migration, and invasion of RA-fibroblast-like synoviocytes (FLS) by attenuating NF-κB signaling, resulting in the suppression of RA progression. Interestingly, WTAP-mediated N6-methyladenosine modification of TGM2 and Myc-mediated WTAP transcription cooperatively contributed to the formation of a TGM2/Myc/WTAP-positive feedback loop through upregulating NF-κB signaling. Moreover, OS could downregulate the activation of the TGM2/Myc/WTAP-positive feedback circuit. Furthermore, OS restrained the proliferation and polarization of M2 macrophages to inhibit the aggregation of lung interstitial CD11b⁺ macrophages, and the effectiveness and non-toxicity of OS in suppressing RA and RA-ILD progression were verified in vivo. Finally, bioinformatics analyses validated the importance and the clinical significance of the OS-regulated molecular network. Taken together, our work emphasized OS as an effective drug candidate and TGM2 as a promising target for RA and RA-ILD treatment.

Pharmacokinetics and bioequivalence evaluation of 2 oral formulations of methotrexate tablets in healthy Chinese volunteers under fasting and fed conditions

Methotrexate is an anti-metabolite drug that is frequently used for rheumatoid arthritis treatment. This study is aimed at evaluating the bioequivalence of 2 methotrexate tablets (2.5 mg) under fasting and fed conditions in healthy Chinese volunteers. A single-center, randomized, open-label, two-drug, two-period, crossover, single-dose trial protocol was designed. Fifty-two healthy Chinese participants were enrolled and randomly classified into fasting (n = 26) and fed (n = 26) group. Fifty of them participated in the whole trial course. Blood samples for pharmacokinetic (PK) analysis were collected 1 h before and up to 24 h after drug administration. To evaluate the bioequivalence of test and reference tablets, PK parameters including maximum plasma drug concentration (C_max), time to reach maximum concentration (T_max), area under the plasma concentration-time curve from time 0 to the last measurable concentration (AUC_0-t), and area under the plasma concentration-time curve from time 0 to infinity (AUC_0-∞) were calculated. Our data revealed that 90% CIs of geometric mean ratio of the test or reference drugs for C_max, AUC_0-t, and AUC_0-∞ fell within the acceptance range for bioequivalence (80-125%). Besides, it is worthwhile to mention that C_max and T_max in the fed group were lower than those in the fasting group. Interestingly, the absorption, measured by AUC, did not have significant difference in both groups. There were no suspected serious adverse reactions or serious adverse events over the entire trial. Our results demonstrated that the test and reference tablets were bioequivalent under fasting and fed conditions.

Reestablish immune tolerance in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease. Despite the wide use of conventional synthetic, targeted and biologic disease modifying anti-rheumatic drugs (DMARDs) to control its radiological progress, nearly all DMARDs are immunologically non-selective and do not address the underlying immunological mechanisms of RA. Patients with RA often need to take various DMARDs long-term or even lifelong and thus, face increased risks of infection, tumor and other adverse reactions. It is logical to modulate the immune disorders and restore immune balance in patients with RA by restoring immune tolerance. Indeed, approaches based on stem cell transplantation, tolerogenic dendritic cells (tolDCs), and antigen-based tolerogenic vaccination are under active investigation, and some have already transformed from wet bench research to clinical investigation during the last decade. Among them, clinical trials on stem cell therapy, especially mesenchymal stem cells (MSCs) transplantation are most investigated and followed by tolDCs in RA patients. On the other hand, despite active laboratory investigations on the use of RA-specific peptide-/protein-based tolerogenic vaccines for T cell, clinical studies on RA patients are much limited. Overall, the preliminary results of these clinical studies are promising and encouraging, demonstrating their safety and effectiveness in the rebalancing of T cell subsets; particular, the recovery of RA-specific Treg with increasing anti-inflammatory cytokines and reduced proinflammatory cytokines. Future studies should focus on the optimization of transplanted stem cells, the preparation of tolDCs, and tolerogenic vaccines with RA-specific protein or peptide, including their dosage, course, and route of administration with well-coordinated multi-center randomized clinical control researches. With the progress of experimental and clinical studies, generating and restoring RA-specific immune tolerance may bring revolutionary changes to the clinical management of RA in the near future.

Computational algorithmic and molecular dynamics study of functional and structural impacts of non-synonymous single nucleotide polymorphisms in human DHFR gene

Human dihydrofolate reductase (DHFR) is a conserved enzyme that is central to folate metabolism and is widely targeted in pathogenic diseases as well as cancers. Although studies have reported the fact that genetic mutations in DHFR leads to a rare autosomal recessive inborn error of folate metabolism and drug resistance, there is a lack of an extensive study on how the deleterious non-synonymous SNPs (nsSNPs) disrupt its phenotypic effects. In this study, we aim at discovering the structural and functional consequences of nsSNPs in DHFR by employing a combined computational approach consisting of ten recently developed in silico tools for identification of damaging nsSNPs and molecular dynamics (MD) simulation for getting deeper insights into the magnitudes of damaging effects. Our study revealed the presence of 12 most deleterious nsSNPs affecting the native phenotypic effects, with three (R71T, G118D, Y122D) identified in the co-factor and ligand binding active sites. MD simulations also suggested that these three SNPs particularly Y122D, alter the overall structural flexibility and dynamics of the native DHFR protein which can provide more understandings into the crucial roles of these mutants in influencing the loss of DHFR function.

Targeting Folate Metabolism Is Selectively Cytotoxic to Glioma Stem Cells and Effectively Cooperates with Differentiation Therapy to Eliminate Tumor-Initiating Cells in Glioma Xenografts

Glioblastoma (GBM) is one of the deadliest of all human cancers. Developing therapies targeting GBM cancer stem cells or glioma stem cells (GSCs), which are deemed responsible for the malignancy of GBM due to their therapy resistance and tumor-initiating capacity, is considered key to improving the dismal prognosis of GBM patients. In this study, we found that folate antagonists, such as methotrexate (MTX) and pemetrexed, are selectively cytotoxic to GSCs, but not to their differentiated counterparts, normal fibroblasts, or neural stem cells in vitro, and that the high sensitivity of GCSs to anti-folates may be due to the increased expression of RFC-1/SLC19A1, the reduced folate carrier that transports MTX into cells, in GSCs. Of note, in an in vivo serial transplantation model, MTX alone failed to exhibit anti-GSC effects but promoted the anti-GSC effects of CEP1347, an inducer of GSC differentiation. This suggests that folate metabolism, which plays an essential role specifically in GSCs, is a promising target of anti-GSC therapy, and that the combination of cytotoxic and differentiation therapies may be a novel and promising approach to effectively eliminate cancer stem cells.

Recent advances on signaling pathways and their inhibitors in rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by systemic synovitis leading to joint destruction in which imbalances in pro-inflammatory and anti-inflammatory cytokines promote the induction of autoimmunity. Some pro-inflammatory cytokines can trigger the signaling pathways which responsible for immune-mediated inflammation in RA, and the activated signaling pathways produce pro-inflammatory cytokines, resulting in aggravation of RA. Hence, understanding of the signaling pathways and their inhibitors might be advantageous in the development of therapeutic targets and new drugs for RA. In the current review, we summarize the signaling pathways involved in the pathogenesis of RA as well as the potential role of specific inhibitors in its management. We hope this paper may serve a reference for future studies on signaling pathways implicated in the pathogenesis of RA and benefit the treatment of RA.

Anti-inflammatory and Hepatoprotective Effects of Quercetin in an Experimental Model of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation in the joints. Although methotrexate (MX) is the first-line treatment, side effects are common. This study aimed to investigate the effects of quercetin (QT) and/or MX on inflammation and systemic toxicity in a rat model of RA. Male Wistar rats were divided into control (C), RA, QT, MX, and QT + MX groups (n=6). The RA induction consisted of three intra-articular injections of methylated bovine serum albumin (1×/week) in the temporomandibular joint (TMJ). QT (25 mg/kg) and/or MX (0.75 mg) administration occurred by oral gavage daily. We performed mechanical hyperalgesia in TMJ, leukocyte recruitment in synovial fluid, histopathology, and immunohistochemistry (TNF-α, IL-17, and IL-10) in synovial membrane and toxicity parameters. The RA showed a reduction in the nociceptive threshold (p<0.001), increase in leukocyte recruitment in synovial fluid (p<0.001), intense inflammatory infiltrate (p<0.001), and intense immunoexpression of TNF-α, IL-17, and IL-10 in the synovial membrane (p<0.001) compared to C (p<0.001). QT and/or MX therapy reduced inflammatory parameters (p<0.001). However, downregulation of IL-10 was observed only in the groups that received MX (p<0.001). Leukocytosis was seen in RA (p<0.05), but QT and/or MX reversed it (p<0.05). MX was associated with pathological changes in the liver and higher levels of transaminases when compared to the other groups (p<0.05). QT co-administered with MX reversed this hepatotoxicity (p<0.05). There were no alterations in the kidney between the groups (p>0.05). QT has potential to support MX therapy, showing anti-inflammatory and hepatoprotective effects in this model.