Geldanamycin induces apoptosis and inhibits inflammation in fibroblast‐like synoviocytes isolated from rheumatoid arthritis patients

Daptomycin alleviates collagen-induced arthritis via suppressing inflammatory cytokines and NF-κB pathway

Rheumatoid arthritis (RA) is a chronic autoimmune disease, and its pathogenic factors include bacterial infection and immune inflammation. Daptomycin (DAP) is a cyclic lipopeptide that has been approved to treat skin infections, bacteremia and right-sided endocarditis due to its effective antibacterial effects against most Gram-positive pathogenic bacteria. Herein, we focus on whether DAP exerts anti-inflammatory activity on RA to expand DAP drug indications. Our studies are first time to evaluate anti-inflammatory effect and reveal its molecular pharmacological mechanism of DAP on lipopolysaccharide-activated macrophage and collagen-induced arthritis (CIA) mice. In vitro cytological studies show that 10 µg/mL DAP inhibits secretion of IL-1β, IL-6 and TNF-α to alleviate cell inflammation, and the phosphorylation level of p65 (p-p65) of RAW 264.7 cells is decreased under DAP exposure. Administration with 10 mg/kg/2d DAP via intravenous injection on CIA mice significantly reduces arthritis symptom by inhibiting p-p65 level and decreasing serum level of IL-6, IL-1β and TNF-α. Moreover, our study is the first time to reveal new immunomodulatory effects of DAP on RA, which provides a pharmacological basis for new clinical applications of DAP for other immune-related diseases except to bacterial infections.

Introducing Molecular Chaperones into the Causality and Prospective Management of Autoimmune Hepatitis

Molecular chaperones influence the immunogenicity of peptides and the activation of effector T cells, and their pathogenic roles in autoimmune hepatitis are unclear. Heat shock proteins are pivotal in the processing and presentation of peptides that activate CD8+ T cells. They can also induce regulatory B and T cells and promote immune tolerance. Tapasin and the transporter associated with antigen processing-binding protein influence the editing and loading of high-affinity peptides for presentation by class I molecules of the major histocompatibility complex. Their over-expression could enhance the autoimmune response, and their deficiency could weaken it. The lysosome-associated membrane protein-2a isoform in conjunction with heat shock cognate 70 supports the importation of cytosolic proteins into lysosomes. Chaperone-mediated autophagy can then process the peptides for activation of CD4+ T cells. Over-expression of autophagy in T cells may also eliminate negative regulators of their activity. The human leukocyte antigen B-associated transcript three facilitates the expression of class II peptide receptors, inhibits T cell apoptosis, prevents T cell exhaustion, and sustains the immune response. Immunization with heat shock proteins has induced immune tolerance in experimental models and humans with autoimmune disease by inducing regulatory T cells. Therapeutic manipulation of other molecular chaperones may promote T cell exhaustion and induce tolerogenic dendritic cells. In conclusion, molecular chaperones constitute an under-evaluated family of ancillary proteins that could affect the occurrence, severity, and outcome of autoimmune hepatitis. Clarification of their contributions to the immune mechanisms and clinical activity of autoimmune hepatitis could have therapeutic implications.

Danggui Niantong granules ameliorate rheumatoid arthritis by regulating intestinal flora and promoting mitochondrial apoptosis

CONTEXT

Danggui Niantong Granules (DGNTG) are a valid and reliable traditional herbal formula, commonly used in clinical practice to treat rheumatoid arthritis (RA). However, the mechanism of its effect on RA remains unclear.

OBJECTIVE

An investigation of the therapeutic effects of DGNTG on RA.

MATERIALS AND METHODS

Twenty-four male Sprague-Dawley (SD) rats were divided into four groups: control, model, DGNTG (2.16 g/kg, gavage), methotrexate (MTX) (1.35 mg/kg, gavage) for 28 days. The morphology of synovial and ankle tissues was observed by haematoxylin-eosin staining. The responses of mitochondrial apoptosis were assessed by qPCR, Western blotting and immunohistochemical staining. Rat faeces were analysed by 16S rRNA sequencing.

RESULTS

Our results showed that DGNTG treatment reduced AI scores (7.83 ± 0.37 vs. 4.67 ± 0.47, p < 0.01) and paw volumes (7.63 ± 0.17 vs. 6.13 ± 0.11, p < 0.01) compared with the model group. DGNTG also increased the expression of Bax (0.34 ± 0.03 vs. 0.73 ± 0.03, p < 0.01), cytochrome c (CYTC) (0.24 ± 0.02 vs. 0.64 ± 0.01, p < 0.01) and cleaved caspase-9 (0.24 ± 0.04 vs. 0.83 ± 0.08, p < 0.01), and decreased bcl-2 (1.70 ± 0.11 vs. 0.60 ± 0.09, p < 0.01) expression. DGNTG treatment regulated the structure of gut microbiota.

DISCUSSION AND CONCLUSIONS

DGNTG ameliorated RA by promoting mitochondrial apoptosis, which may be associated with regulating gut microbiota structure. DGNTG can be used as a supplement and alternative drug for the treatment of RA; its ability to prevent RA deserves further study.

Inhibitory Effects of Cold Atmospheric Plasma on Inflammation and Tumor-Like Feature of Fibroblast-Like Synoviocytes from Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, debilitating systemic disease characterized by chronic inflammation and progressive joint destruction. Fibroblast-like synoviocytes (FLSs) are one of the most important players in the pathophysiology of RA, acting like tumor cells and secreting inflammatory cytokines. Previous research has shown that cold atmospheric plasma (CAP) inhibits cancer cells and may have anti-inflammatory properties. This study examined the effects of argon plasma jet-produced CAP on the suppression of invasion and inflammation caused by cultured RA-FLS. The findings revealed that CAP reduced cell viability and elevated the percentage of apoptotic RA-FLS by producing reactive oxygen species. Carboxyfluorescein diacetate succinimidyl ester (CFSE) staining confirmed that CAP could decrease the proliferation of RA-FLS. Furthermore, CAP effectively reduced the production of inflammatory factors (e.g., NF-κB and IL-6) as well as destructive factors like receptor activator of nuclear factor kappa-B ligand (RANKL) and matrix metalloproteinases-3 (MMP-3). These data suggest that CAP could be a promising treatment for slowing the progression of RA by reducing tumor-like features and inflammation in RA-FLS.

Apoptosis, Autophagy, NETosis, Necroptosis, and Pyroptosis Mediated Programmed Cell Death as Targets for Innovative Therapy in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that can lead to clinical manifestations of systemic diseases. Its leading features include chronic synovial inflammation and degeneration of the bones and joints. In the past decades, multiple susceptibilities for rheumatoid arthritis have been identified along with the development of a remarkable variety of drugs for its treatment; which include analgesics, glucocorticoids, nonsteroidal anti-inflammatory medications (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), and biologic response modifiers (bDMARDs). Despite the existence of many clinical treatment options, the prognosis of some patients remains poor due to complex mechanism of the disease. Programmed cell death (PCD) has been extensively studied and ascertained to be one of the essential pathological mechanisms of RA. Its dysregulation in various associated cell types contributes to the development of RA. In this review, we summarize the role of apoptosis, cell death-associated neutrophil extracellular trap formation, necroptosis, pyroptosis, and autophagy in the pathophysiology of RA to provide a theoretical reference and insightful direction to the discovery and development of novel therapeutic targets for RA.

Effect of Acupuncture Stimulation on Improving the Immunity of Synovial Tissue in Rheumatoid Joints via MAPK Pathway

Purpose: Acupuncture treatment of rheumatoid arthritis (RA) has a long history and has been widely recognized in the medical community. However, its mechanism of action still is rarely uncovered. In the present study, the effects of acupuncture on the immune function and MAPK pathway in synovial tissue of rats with RA were investigated; it aimed to explore the effect and mechanism of acupuncture on alleviating RA. Methods: Rats were randomly divided into control, model and acupuncture groups, 15 rats each group, and RA rat model was induced via bovine type II collagen in complete Freund’s adjuvant. The acupuncture group received "Zusanli" and "Shenshu" warm acupuncture treatment on the first day after modeling, acupuncture stimulation once a day for 21 days. The rat weight and degree of joint swelling were recorded and calculated. The ankle joint histopathology was observed by H&E staining. Serum inflammatory cytokines were detected using ELISA. An automatic biochemical analyzer was used to test serum IgG, IgM and IgA levels. Transcription factors T-bet, GATA3, RORγT, Foxp3 mRNA were monitored through RT-qPCR technology. Further, the expression of key targets of MAPK signal or phosphorylation in synovial tissue were determined using Western blotting. Results: Acupuncture relieved the joint swelling and weight loss of RA rats, ameliorated the pathological damage of the ankle joint, significantly increased the serum IgG, IgM, IgA and T-bet, and Foxp3 levels, and reduced the levels of IL-1β, IL-6, TNF-α, GATA3, and RORγT; down-regulated synovial tissue p-p38MAPK, p-JNK, and p-ERK1/2 levels and protein phosphorylation ratio (P<0.05). Conclusion: Acupuncture stimulation can improve the joint damage and promote the immune function of RA rats, possibly via blocking the expression of MAPK pathway in synovial tissue. This study provides a scientific and promising reference for acupuncture further in the clinical strategy of RA.

Natural heat shock protein 90 inhibitors in cancer and inflammation

Heat shock protein (HSP)90 is the most abundant HSPs, which are chaperone molecules whose major roles are cell protection and maintenance by means of aiding the folding, the stabilization and the remodeling of a wide range of proteins. A few hundreds of proteins depend on HSP90 chaperone activity, including kinases and transcriptional factors that play essential roles in cancer and inflammation, so that HSP90-targeted therapies have been considered as a potential strategy for the treatment of cancer and inflammatory-associated diseases. HSP90 inhibition by natural, semi-synthetic and synthetic compounds have yield promising results in pre-clinical studies and clinical trials for different types of cancers and inflammation. Natural products are a huge source of biologically active compounds widely used in drug development due to the great diversity of their metabolites which are capable to modulate several protein functions. HSP90 inhibitors have been isolated from bacteria, fungi and vegetal species. These natural compounds have a noteworthy ability to modulate HSP90 activity as well as serve as scaffolds for the development of novel synthetic or semi-synthetic inhibitors. Over a hundred clinical trials have evaluated the effect of HSP90 inhibitors as adjuvant treatment against different types of tumors and, currently, new studies are being developed to gain sight on novel promising and more effective approaches for cancer treatment. In this review, we present the naturally occurring HSP90 inhibitors and analogues, discussing their anti-cancer and anti-inflammatory effects.