Research progress on serological indices and their clinical application in rheumatoid arthritis

Sinomenine ameliorates fibroblast-like synoviocytes dysfunction by promoting phosphorylation and nuclear translocation of CRMP2

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial inflammation and arthritic pain. Sinomenine (SIN), derived from the rhizome of Chinese medical herb Qing Teng (scientific name: Sinomenium acutum (Thunb.) Rehd. Et Wils), has a longstanding use in Chinese traditional medicine for treating rheumatoid arthritis. It has been shown to possess anti-inflammatory, analgesic, and immunosuppressive effects with minimal side-effects clinically. However, the mechanisms governing its effects in treatment of joint pathology, especially on fibroblast-like synoviocytes (FLSs) dysfunction, and arthritic pain remains unclear.

AIM

This study aimed to investigate the effect and underlying mechanism of SIN on arthritic joint inflammation and joint FLSs dysfunctions.

MATERIALS AND METHODS

Collagen-induced arthritis (CIA) was induced in rats and the therapeutic effects of SIN on joint pathology were evaluated histopathologically. Next, we conducted a series of experiments using LPS-induced FLSs, which were divided into five groups (Naïve, LPS, SIN 10, 20, 50 μg/ml). The expression of inflammatory factors was measured by qPCR and ELISA. The invasive ability of cells was detected by modified Transwell assay and qPCR. Transwell migration and cell scratch assays were used to assess the migration ability of cells. The distribution and content of relevant proteins were observed by immunofluorescence and laser confocal microscopy, as well as Western Blot and qPCR. FLSs were transfected with plasmids (CRMP2 T514A/D) to directly modulate the post-translational modification of CRMP2 protein and downstream effects on FLSs function was monitored.

RESULTS

SIN alleviated joint inflammation in rats with CIA, as evidenced by improvement of synovial hyperplasia, inflammatory cell infiltration and cartilage damage, as well as inhibition of pro-inflammatory cytokines release from FLSs induced by LPS. In vitro studies revealed a concentration-dependent suppression of SIN on the invasion and migration of FLSs induced by LPS. In addition, SIN downregulated the expression of cellular CRMP2 that was induced by LPS in FLSs, but increased its phosphorylation at residue T514. Moreover, regulation of pCRMP2 T514 by plasmids transfection (CRMP2 T514A/D) significantly influenced the migration and invasion of FLSs. Finally, SIN promoted nuclear translocation of pCRMP2 T514 in FLSs.

CONCLUSIONS

SIN may exert its anti-inflammatory and analgesic effects by modulating CRMP2 T514 phosphorylation and its nuclear translocation of FLSs, inhibiting pro-inflammatory cytokine release, and suppressing abnormal invasion and migration. Phosphorylation of CRMP2 at the T514 site in FLSs may present a new therapeutic target for treating inflammatory joint's destruction and arthritic pain in RA.

Manganese-Based Immunomodulatory Nanocomposite with Catalase-Like Activity and Microwave-Enhanced ROS Elimination Ability for Efficient Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a chronic autoimmune disease commonly associated with the accumulation of hyperactive immune cells (HICs), particularly macrophages of pro-inflammatory (M1) phenotype, accompanied by the elevated level of reactive oxygen species (ROS), decreased pH and O2 content in joint synovium. In this work, an immunomodulatory nanosystem (IMN) is developed for RA therapy by modulating and restoring the function of HICs in inflamed tissues. Manganese tetraoxide nanoparticles (Mn3 O4 ) nanoparticles anchored on UiO-66-NH2 are designed, and then the hybrid is coated with Mn-EGCG film, further wrapped with HA to obtain the final nanocomposite of UiO-66-NH2 @Mn3 O4 /Mn-EGCG@HA (termed as UMnEH). When UMnEH diffuses to the inflammatory site of RA synovium, the stimulation of microwave (MW) irradiation and low pH trigger the slow dissociation of Mn-EGCG film. Then the endogenously overexpressed hydrogen peroxide (H2 O2 ) disintegrates the exposed Mn3 O4 NPs to promote ROS scavenging and O2 generation. Assisted by MW irradiation, the elevated O2 content in the RA microenvironment down-regulates the expression of hypoxia-inducible factor-1α (HIF-1α). Coupled with the clearance of ROS, it promotes the re-polarization of M1 phenotype macrophages into anti-inflammatory (M2) phenotype macrophages. Therefore, the multifunctional UMnEH nanoplatform, as the IMN, exhibits a promising potential to modulate and restore the function of HICs and has an exciting prospect in the treatment of RA.

Curcumin Co-Encapsulation Potentiates Anti-Arthritic Efficacy of Meloxicam Biodegradable Nanoparticles in Adjuvant-Induced Arthritis Animal Model

This study aimed to evaluate the anti-arthritic activity of curcumin and meloxicam co-loaded PLGA nanoparticles in adjuvant-induced arthritic rats. PLGA nanoparticles encapsulating curcumin (nCur) and meloxicam (nMlx) alone and in combination (nCur/Mlx) were used to characterize zeta size and potential, polydispersity index, encapsulation efficiency (%), compound-polymer interactions (FT-IR analysis), and surface morphology (SEM imaging). In vivo, Complete Freund's adjuvant-induced arthritic rats were intraperitoneally (i.p.) administered with curcumin, meloxicam, curcumin plus meloxicam, nCur, nMlx, and nCur/Mlx for 28 consecutive days. Results showed that nCur, nMlx, and nCur/Mlx significantly (p ≤ 0.05) reduced paw swelling and arthritic score, restored body weight and the immune organ index (thymus and spleen), as well as attenuated serum inflammatory markers (RF, CRP, and PGE2) and oxidative stress parameters (MDA, SOD, and CAT) in adjuvant-induced arthritic rats compared to free compounds. In addition, mono- and dual-compound-loaded nanoparticles significantly (p ≤ 0.05) down-regulated pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), up-regulated anti-inflammatory cytokines (IL-4, IL-10, and IFN-γ), and modulated OPG and RANKL expressions in paw tissue. The aforementioned results were further confirmed through radiological and histopathological examinations. Furthermore, the anti-arthritic effect of nCur/Mlx was notably (p ≤ 0.05) enhanced compared to nCur or nMlx alone. In conclusion, the co-nanoencapsulation of curcumin could potentiate the anti-arthritic activity of meloxicam and could provide a novel therapeutic approach for the formulation of nanocarrier pharmaceutical products for the management of arthritis.

SPARC: a potential target for functional nanomaterials and drugs

Secreted protein acidic and rich in cysteine (SPARC), also termed osteonectin or BM-40, is a matricellular protein which regulates cell adhesion, extracellular matrix production, growth factor activity, and cell cycle. Although SPARC does not perform a structural function, it, however, modulates interactions between cells and the surrounding extracellular matrix due to its anti-proliferative and anti-adhesion properties. The overexpression of SPARC at sites, including injury, regeneration, obesity, cancer, and inflammation, reveals its application as a prospective target and therapeutic indicator in the treatment and assessment of disease. This article comprehensively summarizes the mechanism of SPARC overexpression in inflammation and tumors as well as the latest research progress of functional nanomaterials in the therapy of rheumatoid arthritis and tumors by manipulating SPARC as a new target. This article provides ideas for using functional nanomaterials to treat inflammatory diseases through the SPARC target. The purpose of this article is to provide a reference for ongoing disease research based on SPARC-targeted therapy.

LKB1 Regulates Inflammation of Fibroblast-like Synoviocytes from Patients with Rheumatoid Arthritis via AMPK-Dependent SLC7A11-NOX4-ROS Signaling

Fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) patients have increased reactive oxygen species (ROS) levels and an impaired redox balance compared with FLS from control patients. Liver kinase B1 (LKB1) plays a key role in ROS scavenging and cellular metabolism in various cancers. Here, we aimed to determine the specific mechanism of LKB1 in RA pathogenesis. FLS were obtained from RA patients (n = 10). siRNA-induced LKB1 deficiency in RA FLS increased ROS levels via NADPH oxidase 4 (NOX4) upregulation. RA FLS migration and expression of inflammatory factors, including interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-alpha (TNF-α), and vascular endothelial growth factor (VEGF), were enhanced by LKB1 deficiency. LKB1-deficient RA FLS showed increased sensitivity to oxidative stress damage caused by hydrogen peroxidase exposure. siRNA-induced solute carrier family 7 member 11 (SLC7A11) deficiency in RA FLS enhanced NOX4 and ROS expression and increased cell migration. When LKB1-deficient RA FLS were stimulated with an AMP-activated protein kinase (AMPK) activator, the LKB1-inhibition-induced cell migration significantly decreased through the restoration of SLC7A11/NOX4 expression. LKB1 regulates the AMPK-mediated SLC7A11-NOX4-ROS pathway to control cell migration and inflammation. Our data indicate that LKB1 is a key regulator of redox homeostasis in RA FLS.

Targeting matrix metalloproteases: A promising strategy for herbal medicines to treat rheumatoid arthritis

As a type of metalloproteinase, matrix metalloproteinases (MMPs) can be divided into collagenase, gelatinase, stromelysins, membrane-type (MT)-MMPs and heterogeneous subgroups according to their structure and function. MMP contents in the human body are strictly regulated, and their synthesis, activation and inhibition processes should be kept in a certain balance; otherwise, this would result in the occurrence of various diseases. Rheumatoid arthritis (RA) is a known immune-mediated systemic inflammatory disease that is affected by a variety of endogenous and exogenous factors. In RA development, MMPs act as important mediators of inflammation and participate in the degradation of extracellular matrix substrates and digestion of fibrillar collagens, leading to the destruction of joint structures. Interestingly, increasing evidence has suggested that herbal medicines have many advantages in RA due to their multitarget properties. In this paper, literature was obtained through electronic databases, including the Web of Science, PubMed, Google Scholar, Springer, and CNKI (Chinese). After classification and analysis, herbal medicines were found to inhibit the inflammatory process of RA by regulating MMPs and protecting joint structures. However, further preclinical and clinical studies are needed to support this view before these herbal medicines can be developed into drugs with actual application to the disease.