Low-dose ethanol consumption inhibits neutrophil extracellular traps formation to alleviate rheumatoid arthritis

Immune-Enhancing Effects of Two Potential Probiotic Strains Latilactobacillus curvatus WiKim0169 and Pediococcus acidilactici WiKim0170 in a Cyclophosphamide-Induced Immunosuppression Rat Model

Emerging evidence suggests that probiotics are beneficial for immunity and play a crucial role in regulating gut microbiota. However, the immune-enhancing effects of specific bacterial species remain uncertain. This study investigated the effects of two potential probiotic strains, Latilactobacillus curvatus WiKim0169 (Wilac L004, W4) and Pediococcus acidilactici WiKim0170 (Wilac L002, W2) isolated from fermented cabbage, on immune enhancement and gut microbiota changes in a cyclophosphamide-induced immunosuppression rat model. The results revealed that W4 and W2 improved natural killer cell activity, serum nitrite, and immunoglobulin levels. They also increased cytokine levels and activated the nuclear factor-κB pathway, substantiating the underlying mechanism of the immune-enhancing effects. Additionally, both strains altered gut microbiota composition by increasing bacteria that are being studied for their potential association with immune function. Taken together, both strains improved immune-related biomarkers and the gut microbiota. These findings suggest W4 and W2 as promising probiotics with immune-enhancing properties.

Flavonoid-rich extract of Paederia scandens (Lour.) Merrill improves hyperuricemia by regulating uric acid metabolism and gut microbiota

Paederia scandens (Lour.) Merrill flavonoid-rich extract (PSMF) has shown excellent xanthine oxidase (XOD) inhibitory activity in our previous study. However, the efficacy of PSMF in mitigating hyperuricemia (HUA) remains to be elucidated. In this study, we investigated the effects and mechanisms of PSMF on alleviating in HUA mice. The results showed that PSMF intervention reduced serum levels of uric acid (UA), creatinine (CRE), and blood urea nitrogen (BUN), and inhibited the activities of XOD and adenosine deaminase (ADA). In addition, PSMF treatment not only attenuated the inflammatory response and renal damage but also regulated the expression of UA synthesis genes and UA excretion genes. Finally, PSMF ameliorated gut microbiota dysbiosis in HUA mice by enriching the abundance of short-chain fatty acid (SCFA)-producing bacteria. In summary, PSMF appears to be a promising natural source for the prevention and treatment of HUA.

Resolution of inflammation during rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes synovial joint inflammation as well as bone destruction and erosion, typically characterized by joint pain, swelling, and stiffness, with complications and persistent pain after remission posing a significant health burden for RA patients. The etiology of RA has not yet been fully elucidated, but a large number of studies have shown that the initiation of inflammation in RA is closely related to T-cell activation, the production of a variety of pro-inflammatory cytokines, macrophage M1/M2 imbalance, homeostatic imbalance of the intestinal flora, fibroblast-like synoviocytes (FLSs) and synovial tissue macrophages (STMs) in the synovial lumen of joints that exhibit an aggressive phenotype. While the resolution of RA is less discussed, therefore, we provided a systematic review of the relevant remission mechanisms including blocking T cell activation, regulating macrophage polarization status, modulating the signaling pathway of FLSs, modulating the subpopulation of STMs, and inhibiting the relevant inflammatory factors, as well as the probable causes of persistent arthritis pain after the remission of RA and its pain management methods. Achieving resolution in RA is crucial for improving the quality of life and long-term prognosis of patients. Thus, understanding these mechanisms provide novel potential for further drug development and treatment of RA.

Jingfang Granules alleviates the lipid peroxidation induced ferroptosis in rheumatoid arthritis rats by regulating gut microbiota and metabolism of short chain fatty acids

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation, bone and cartilage damage, musculoskeletal pain, swelling, and stiffness. Inflammation is one of the key factors that induce RA. Jingfang Granule (JFG) is a traditional Chinese medicine (TCM) with significant anti-inflammatory effects. Clinical studies have confirmed that JFG can be used to treat RA, but the mechanism is still vague.

PURPOSE

This study was designed to evaluate the protective function and the mechanism of JFG on rats with RA.

STUDY DESIGN AND METHODS

Complete Freud's Adjuvant (CFA) was used to establish a rat RA model, and JFG or Diclofenac Sodium (Dic) was orally administered. Foot swelling and hematoxylin eosin (H&E) staining were used to test the therapeutic effect of JFG on RA treatment, while ELISA kits were used to detect serum cytokines. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and reactive oxygen species (ROS) were used to evaluate oxidative stress levels. The integration of label-free proteomics, fecal short chain fatty acid (SCFA) targeted metabolomics, peripheral blood SCFA, medium and long chain fatty acid targeted metabolomics, and 16S rDNA sequencing of gut microbiota were used to screen the mechanism. Western blot technology was used to validate the results of multiple omics studies. Serum D-Lactic acid, lipopolysaccharide specific IgA antibody (LPS IgA), diamine oxidase (DAO), and colon Claudin 5 and ZO-1 were used to evaluate the intestinal barrier.

RESULTS

The results confirmed that JFG effectively protected rats from RA injury, which was confirmed by improved foot swelling and synovial pathology. At the same time, JFG reduced the levels of TNF-α, IL-1β, and IL-6 in serum by inhibiting the NLRP3 inflammasome signaling pathway and TLR4/NF-κB signaling pathway in synovial tissue. Multiple omics studies indicated that JFG increased the abundance of gut microbiota and regulated the number of gut bacteria, thereby increased the levels of Acetic acid, Propionic acid, and Butyric acid in the gut and serum of RA rats, which activated AMPK to regulate fatty acid metabolism and fatty acid biosynthesis, thereby inhibited lipid oxidative stress induced ferroptosis to improve tissue damage caused by RA. Meanwhile, JFG improved the intestinal barrier by upregulating the expresses of Claudin 5 and ZO-1, which was confirmed by low concentrations of D-Lactic acid, LPS-SIgA and DAO in serum.

CONCLUSIONS

This study confirmed that JFG improved the disturbance of fatty acid metabolism by modulating gut microbiota and the production of fecal SCFAs to activate AMPK, and then inhibited ferroptosis caused by lipid oxidative stress in synovium tissue and prevented AR injury. This study proposes for the first time to investigate the mechanism of JFG treatment for RA from the perspective of the "Gut-joint" axis, and provides a promising approach for the treatment of RA.

Nanoscopy reveals integrin clustering reliant on kindlin-3 but not talin-1

BACKGROUND

Neutrophils are the most abundant leukocytes in human blood, and their recruitment is essential for innate immunity and inflammatory responses. The initial and critical step of neutrophil recruitment is their adhesion to vascular endothelium, which depends on G protein-coupled receptor (GPCR) triggered integrin inside-out signaling that induces β2 integrin activation and clustering on neutrophils. Kindlin-3 and talin-1 are essential regulators for the inside-out signaling induced β2 integrin activation. However, their contribution in the inside-out signaling induced β2 integrin clustering is unclear because conventional assays on integrin clustering are usually performed on adhered cells, where integrin-ligand binding concomitantly induces integrin outside-in signaling.

METHODS

We used flow cytometry and quantitative super-resolution stochastic optical reconstruction microscopy (STORM) to quantify β2 integrin activation and clustering, respectively, in kindlin-3 and talin-1 knockout leukocytes. We also tested whether wildtype or Pleckstrin homology (PH) domain deleted kindlin-3 can rescue the kindlin-3 knockout phenotypes.

RESULTS

GPCR-triggered inside-out signaling alone can induce β2 integrin clustering. As expected, both kindlin-3 and talin-1 knockout decreases integrin activation. Interestingly, only kindlin-3 but not talin-1 contributes to integrin clustering in the scenario of inside-out-signaling, wherein a critical role of the PH domain of kindlin-3 was highlighted.

CONCLUSIONS

Since talin was known to facilitate integrin clustering in outside-in-signaling-involved cells, our finding provides a paradigm shift by suggesting that the molecular mechanisms of integrin clustering upon inside-out signaling and outside-in signaling are different. Our data also contradict the conventional assumption that integrin activation and clustering are tightly inter-connected by showing separated regulation of the two during inside-out signaling. Our study provides a new mechanism that shows kindlin-3 regulates β2 integrin clustering and suggests that integrin clustering should be assessed independently, aside from integrin activation, when studying leukocyte adhesion in inflammatory diseases.

The role of neutrophil extracellular traps in inflammatory rheumatic diseases

PURPOSE OF REVIEW

Dysregulation in neutrophil extracellular trap (NET) formation and degradation has been reported in several inflammatory rheumatic diseases. This review summarizes the recent advances in the understanding the role of NETs in the context of inflammatory rheumatic diseases.

RECENT FINDINGS

NET formation is enhanced in peripheral blood of patients with large vessel vasculitis and polymyalgia rheumatica. NETs are detected in affected organs in autoimmune conditions, and they might play pathological roles in tissues. Several understudied medications and supplements suppress NET formation and ameliorate animal models of inflammatory rheumatic diseases. NETs and anti-NET antibodies have potential utility as disease biomarkers.

SUMMARY

Growing evidence has suggested the contribution of NET dysregulation to the pathogenesis of several inflammatory rheumatic diseases. Further research is warranted in regard to clinical impact of modulating aberrant NET formation and clearance in inflammatory rheumatic diseases.

Gut Microbiota Modulation: A Novel Strategy for Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a chronic autoimmune disease that leads to joint inflammation, progressive tissue damage and significant disability, severely impacting patients' quality of life. While the exact mechanisms underlying RA remain elusive, growing evidence suggests a strong link between intestinal microbiota dysbiosis and the disease's development and progression. Differences in microbial composition between healthy individuals and RA patients point to the role of gut microbiota in modulating immune responses and promoting inflammation. Therapies targeting microbiota restoration have demonstrated promise in improving treatment efficacy, enhancing patient outcomes and slowing disease progression. However, the complex interplay between gut microbiota and autoimmune pathways in RA requires further investigation to establish causative relationships and mechanisms. Here, we review the current understanding of the gut microbiota's role in RA pathogenesis and its potential as a therapeutic target.

The Role of Neutrophil Extracellular Traps in the Outcome of Malignant Epitheliomas: Significance of CA215 Involvement

Neutrophil extracellular traps (NETs) were originally discovered as a part of the innate immune response of the host to bacteria. They form a web-like structure that can immobilize microorganisms or exhibit direct antimicrobial properties, such as releasing reactive oxygen species (ROS). NETs are established when neutrophils undergo a sort of cellular death following exposure to ROS, chemokines, cytokines, or other soluble factors. This process results in the release of the neutrophil's DNA in a web-like form, which is decorated with citrullinated histones (H3/H4-cit), neutrophil elastase (NE), and myeloperoxidase (MPO). Emerging studies have put into perspective that NETs play an important role in oncology as they were shown to influence tumor growth, malignant initiation, and proliferation, mediate the transition from endothelial to mesenchymal tissue, stimulate angiogenesis or metastasis, and can even help cancer cells evade the immune response. The role of NETs in cancer therapy resides in their ability to form and act as a mechanical barrier that will provide the primary tumor with a reduced response to irradiation or pharmaceutical penetration. Subsequently, cancer cells are shown to internalize NETs and use them as a strong antioxidant when pharmaceutical treatment is administered. In this review, we explored the role of NETs as part of the tumor microenvironment (TME), in the context of malignant epitheliomas, which are capable of an autonomous production of CA215, a subvariant of IgG, and part of the carcinoembryonic antigen (CEA) superfamily. Studies have shown that CA215 has a functional Fc subdivision able to activate the Fc-gamma-RS receptor on the surface of neutrophils. This activation may afterward stimulate the production of NETs, thus indicating CA215 as a potential factor in cancer therapy surveillance.