Oxidative stress impairs energy metabolism in primary cells and synovial tissue of patients with rheumatoid arthritis

Mitochondrial destabilization in tendinopathy and potential therapeutic strategies

Tendinopathy is a prevalent aging-related disorder characterized by pain, swelling, and impaired function, often resulting from micro-scarring and degeneration caused by overuse or trauma. Current interventions for tendinopathy have limited efficacy, highlighting the need for innovative therapies. Mitochondria play an underappreciated and yet crucial role in tenocytes function, including energy production, redox homeostasis, autophagy, and calcium regulation. Abnormalities in mitochondrial function may lead to cellular senescence. Within this context, this review provides an overview of the physiological functions of mitochondria in tendons and presents current insights into mitochondrial dysfunction in tendinopathy. It also proposes potential therapeutic strategies that focus on targeting mitochondrial health in tenocytes. These strategies include: (1) utilizing reactive oxygen species (ROS) scavengers to mitigate the detrimental effects of aberrant mitochondria, (2) employing mitochondria-protecting agents to reduce the production of dysfunctional mitochondria, and (3) supplementing with exogenous normal mitochondria. In conclusion, mitochondria-targeted therapies hold great promise for restoring mitochondrial function and improving outcomes in patients with tendinopathy. The translational potential of this article: Tendinopathy is challenging to treat effectively due to its poorly understood pathogenesis. This review thoroughly analyzes the role of mitochondria in tenocytes and proposes potential strategies for the mitochondrial treatment of tendinopathy. These findings establish a theoretical basis for future research and the clinical translation of mitochondrial therapy for tendinopathy.

Sera from Rheumatoid Arthritis Patients Induce Oxidative Stress and Pro-Angiogenic and Profibrotic Phenotypes in Human Endothelial Cells

Background: Rheumatoid arthritis (RA) is a long-term autoimmune condition marked by persistent inflammation of the joints and various systemic complications, including endothelial dysfunction, atherosclerosis, and pulmonary fibrosis. Oxidative stress is a key contributor to the pathogenesis of RA, potentially exacerbating vascular damage and promoting pro-angiogenic and profibrotic processes. Objective: This study aims to investigate the effects of sera from RA patients on human umbilical vein endothelial cells (HUVECs), focusing on the induction of oxidative stress, endothelial cell proliferation, migration, and collagen type I synthesis. Methods: Twenty-eight serum samples were collected from RA patients and healthy donors (HDs). HUVECs were exposed to these sera, and intracellular reactive oxygen species (ROS) levels were fluorescently detected using H2DCF-DA. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell migration was evaluated through a scratch wound assay, and collagen type I synthesis was measured using a lentiviral vector expressing the green fluorescent protein (GFP) under the control of the human COL1A1 gene promoter. Results: Exposure to RA sera resulted in a significant increase in intracellular ROS levels in HUVECs compared to HD sera, indicating an elevated state of oxidative stress. RA sera also promoted endothelial cell proliferation and migration, suggesting a pro-angiogenic stimulus. Additionally, RA sera significantly increased collagen type I synthesis in HUVECs, implicating a potential role in profibrotic processes associated with RA. Conclusion: The results of this study emphasize the importance of circulating factors in RA sera in promoting oxidative stress, endothelial dysfunction, and pro-angiogenic and profibrotic phenotypes in endothelial cells. These processes may contribute to the vascular and fibrotic complications observed in RA, highlighting the necessity for additional research into focused therapeutic approaches to alleviate these effects.

Environmental and Genetic Determinants of Ankylosing Spondylitis

Exposure to heavy metals and lifestyle factors like smoking contribute to the production of free oxygen radicals. This fact, combined with a lowered total antioxidant status, can induce even more damage in the development of ankylosing spondylitis (AS). Despite the fact that some researchers are looking for more genetic factors underlying AS, most studies focus on polymorphisms within the genes encoding the human leukocyte antigen (HLA) system. The biggest challenge is finding the effective treatment of the disease. Genetic factors and the influence of oxidative stress, mineral metabolism disorders, microbiota, and tobacco smoking seem to be of great importance for the development of AS. The data contained in this review constitute valuable information and encourage the initiation and development of research in this area, showing connections between inflammatory disorders leading to the pathogenesis of AS and selected environmental and genetic factors.

Relevance of real-time analyzers to determine mitochondrial quality in endothelial cells and oxidative stress in preeclampsia

Oxidative stress and mitochondrial dysfunction are important elements for the pathophysiology of preeclampsia (PE), a multisystemic hypertensive syndrome of pregnancy, characterized by endothelial dysfunction and responsible for a large part of maternal and fetal morbidity and mortality worldwide. Researchers have dedicated their efforts to unraveling the intricate ways in which certain molecules influence both energy metabolism and oxidative stress. Exploring established methodologies from existing literature, shows that these investigations predominantly focus on the placenta, identified as a pivotal source that drives the changes observed in the disease. In this review, we discuss the role of oxidative stress in pathophysiology of PE, as well as metabolic/endothelial dysfunction. We further discuss the use of seahorse analyzers to study real-time bioenergetics of endothelial cells. Although the benefits are clear, few studies have presented results using this method to assess mitochondrial metabolism in these cells. We performed a search on MEDLINE/PubMed using the terms "Seahorse assay and endothelial dysfunction in HUVEC" as well as "Seahorse assay and preeclampsia". From our research, we selected 16 original peer-review papers for discussion. Notably, the first search retrieved studies involving Human Umbilical Vein Endothelial Cells (HUVECs) but none investigating bioenergetics in PE while the second search retrieved studies exploring the technique in PE but none of the studies used HUVECs. Additional studies are required to investigate real-time mitochondrial bioenergetics in PE. Clearly, there is a need for more complete studies to examine the nuances of mitochondrial bioenergetics, focusing on the contributions of HUVECs in the context of PE.

Unraveling hallmark suitability for staging pre- and post-implantation stem cell models

The advent of novel 2D and 3D models for human development, including trophoblast stem cells and blastoids, has expanded opportunities for investigating early developmental events, gradually illuminating the enigmatic realm of human development. While these innovations have ushered in new prospects, it has become essential to establish well-defined benchmarks for the cell sources of these models. We aimed to propose a comprehensive characterization of pluripotent and trophoblastic stem cell models by employing a combination of transcriptomic, proteomic, epigenetic, and metabolic approaches. Our findings reveal that extended pluripotent stem cells share many characteristics with primed pluripotent stem cells, with the exception of metabolic activity. Furthermore, our research demonstrates that DNA hypomethylation and high metabolic activity define trophoblast stem cells. These results underscore the necessity of considering multiple hallmarks of pluripotency rather than relying on a single criterion. Multiplying hallmarks alleviate stage-matching bias.

Mitochondrial functioning in Rheumatoid arthritis modulated by estrogen: Evidence-based insight into the sex-based influence on mitochondria and disease

Alteration of immune response and synovium microvasculature in Rheumatoid arthritis (RA) progression has been suggested to be associated with mitochondrial functioning. Mitochondria, with maternally inherited DNA, exhibit differential response to the female hormone estrogen. Various epidemiological evidence has also shown the prominence of RA in the female population, depicting the role of estrogen in modulating the pathogenesis of RA. As estrogen regulates the expression of differential proteins and associated signaling pathways of RA, its influence on mitochondrial functioning seems evident. Thus, in this review, the studies related to mitochondria and their relation with estrogen and Rheumatoid arthritis were retrieved. We analyzed the different mitochondrial activities that are altered in RA and the possibility of their estrogenic control. The study expands to in silico analysis, revealing the differential mitochondrial proteins expressed in RA and examining these proteins as potential estrogenic targets. It was found that ALDH2, CASP3, and SOD2 are the major mitochondrial proteins involved in RA progression and are also potent estradiol targets. The analysis establishes the role of mitochondrial proteins in RA progression, which were found to be direct or indirect targets of estrogen, depicting its potential for regulating mitochondrial functions in RA.

Bacterial muropeptides promote OXPHOS and suppress mitochondrial stress in mammals

Mitochondrial dysfunction critically contributes to many major human diseases. The impact of specific gut microbial metabolites on mitochondrial functions of animals and the underlying mechanisms remain to be uncovered. Here, we report a profound role of bacterial peptidoglycan muropeptides in promoting mitochondrial functions in multiple mammalian models. Muropeptide addition to human intestinal epithelial cells (IECs) leads to increased oxidative respiration and ATP production and decreased oxidative stress. Strikingly, muropeptide treatment recovers mitochondrial structure and functions and inhibits several pathological phenotypes of fibroblast cells derived from patients with mitochondrial disease. In mice, muropeptides accumulate in mitochondria of IECs and promote small intestinal homeostasis and nutrient absorption by modulating energy metabolism. Muropeptides directly bind to ATP synthase, stabilize the complex, and promote its enzymatic activity in vitro, supporting the hypothesis that muropeptides promote mitochondria homeostasis at least in part by acting as ATP synthase agonists. This study reveals a potential treatment for human mitochondrial diseases.

Mechanisms of vascular invasion after cartilage injury and potential engineering cartilage treatment strategies

Articular cartilage injury is one of the most common diseases in orthopedic clinics. Following an articular cartilage injury, an inability to resist vascular invasion can result in cartilage calcification by newly formed blood vessels. This process ultimately leads to the loss of joint function, significantly impacting the patient's quality of life. As a result, developing anti-angiogenic methods to repair damaged cartilage has become a popular research topic. Despite this, tissue engineering, as an anti-angiogenic strategy in cartilage injury repair, has not yet been adequately investigated. This exhaustive literature review mainly focused on the process and mechanism of vascular invasion in articular cartilage injury repair and summarized the major regulatory factors and signaling pathways affecting angiogenesis in the process of cartilage injury. We aimed to discuss several potential methods for engineering cartilage repair with anti-angiogenic strategies. Three anti-angiogenic tissue engineering methods were identified, including administering angiogenesis inhibitors, applying scaffolds to manage angiogenesis, and utilizing in vitro bioreactors to enhance the therapeutic properties of cultured chondrocytes. The advantages and disadvantages of each strategy were also analyzed. By exploring these anti-angiogenic tissue engineering methods, we hope to provide guidance for researchers in related fields for future research and development in cartilage repair.

The association between dietary intake of branched-chain amino acids and odds and severity of rheumatoid arthritis

This case-control study investigated the link between dietary branched-chain amino acids (BCAAs) and the risk and severity of rheumatoid arthritis (RA). We assessed dietary BCAA intake in 95 RA patients and 190 matched controls using a food frequency questionnaire. We also assessed the disease severity using the disease activity score 28 (DAS-28), ESR, VAS, morning stiffness, and tender and swollen joints. Higher BCAA intake, expressed as a percentage of total protein, was significantly associated with increased risk of RA for total BCAAs (OR 2.14, 95% CI 1.53-3.00, P < 0.001), leucine (OR 2.40, 95% CI 1.70-3.38, P < 0.001), isoleucine (OR 2.04, 95% CI 1.46-2.85, P < 0.001), and valine (OR 1.87, 95% CI 1.35-2.59, P < 0.001). These associations remained significant even after adjusting for potential confounders (P < 0.001). However, BCAA intake did not show any significant association with RA severity in either crude or multivariate models (P > 0.05). Our findings suggest that higher dietary BCAA intake may contribute to the development of RA, but further research is needed to confirm these observations and explore the underlying mechanisms.

A Systematic Review and Meta-analysis on the Impact of Infertility on Men's General Health

CONTEXT

Male infertility has been associated with increased morbidity and mortality.

OBJECTIVE

To perform a systematic review and meta-analysis to provide the most critical evidence on the association between infertility and the risk of incident comorbidities in males.

EVIDENCE ACQUISITION

A systematic review and meta-analysis was performed according to the Meta-analysis of Observational Studies in Epidemiology and Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, and registered on PROSPERO. All published studies on infertile versus fertile men regarding overall mortality and risks of cancer, diabetes, and cardiovascular events were selected from a database search on PubMed, EMBASE, Google Scholar, and Cochrane. Forest plot and quasi-individual patient data meta-analysis were used for pooled analyses. A risk of bias was assessed using the ROBINS-E tool.

EVIDENCE SYNTHESIS

Overall, an increased risk of death from any cause was found for infertile men (hazard risk [HR] 1.37, [95% confidence interval {CI} 1.04-1.81], p = 0.027), and a 30-yr survival probability of 91.0% (95% CI 89.6-92.4%) was found for infertile versus 95.9% (95% CI 95.3-96.4%) for fertile men (p < 0.001). An increased risk emerged of being diagnosed with testis cancer (relative risk [RR] 1.86 [95% CI 1.41-2.45], p < 0.001), melanoma (RR 1.30 [95% CI 1.08-1.56], p = 0.006), and prostate cancer (RR 1.66 [95% CI 1.06-2.61], p < 0.001). As well, an increased risk of diabetes (HR 1.39 [95% CI 1.09-1.71], p = 0.008), with a 30-yr probability of diabetes of 25.0% (95% CI 21.1-26.9%) for infertile versus 17.1% (95% CI 16.1-18.1%) for fertile men (p < 0.001), and an increased risk of cardiovascular events (HR 1.20 [95% CI 1.00-1.44], p = 0.049), with a probability of major cardiovascular events of 13.9% (95% CI 13.3-14.6%) for fertile versus 15.7% (95% CI 14.3-16.9%) for infertile men (p = 0.008), emerged.

CONCLUSIONS

There is statistical evidence that a diagnosis of male infertility is associated with increased risks of death and incident comorbidities. Owing to the overall high risk of bias, results should be interpreted carefully.

PATIENT SUMMARY

Male fertility is a proxy of general men's health and as such should be seen as an opportunity to improve preventive strategies for overall men's health beyond the immediate reproductive goals.

JAK inhibitors improve ATP production and mitochondrial function in rheumatoid arthritis: a pilot study

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease associated by inflammation of the synovial tissue and autoantibody production. Oxidative stress and free radicals are known to be indirectly implicated in joint damage and cartilage destruction in RA. Several studies describe the presence of mitochondrial dysfunction in RA, but few of them follow the dynamics in energy parameters after therapy. The aim of our investigation is to evaluate the direct effect of JAK inhibitors on cellular metabolism (and under induced oxidative stress) in RA patients. Ten newly diagnosed RA patients were included in the study. Peripheral blood mononuclear cells (PBMCs) and plasma were isolated before and 6 months after therapy with JAK inhibitors. A real-time metabolic analysis was performed to assess mitochondrial function and cell metabolism in PBMCs. Sonographic examination, DAS28 and conventional clinical laboratory parameters were determined also prior and post therapy. A significant decrease in proton leak after therapy with JAK inhibitors was found. The increased production of ATP indicates improvement of cellular bioenergetics status. These findings could be related to the catalytic action of JAK inhibitors on oxidative phosphorylation which corresponds to the amelioration of clinical and ultra-sonographic parameters after treatment. Our study is the first to establish the dynamics of mitochondrial parameters in PBMCs from RA patients before and after in vivo therapy with JAK inhibitors.

Anti-inflammatory and anti-oxidant activities of mesenchymal stem cells in chemically induced arthritic rats

BACKGROUND

Mesenchymal stem cells (MSCs) have been extensively used as cell-based treatments for decades due to their anti-inflammatory, immunomodulatory, and healing abilities. The intent of our study was to determine the efficacy of MSCs in alleviating rheumatoid arthritis (RA) induced by Complete Freund's adjuvant (CFA) and to investigate the anti-inflammatory and antioxidant characteristics of MSCs.

METHODS AND RESULTS

Intrapedally injecting 0.1 ml of CFA directly into the footpad of the right hind paw daily for 2 days was used to induce RA. Arthritic rats received four doses of MSCs (1 × 106 cells/rat/dose) intravenously through the lateral tail vein. Our results showed that arthritic rats treated with MSCs exhibited reduced levels of paw edema. Furthermore, arthritic rats treated with MSCs exhibited a significant decrease in the levels of RF, CRP, IL-1β, TNF-α, IL-17 and ADAMTS-5, along with a significant increase in the levels of IL-4 and TIMP-3. Additionally, MSCs significantly reduced the expression of TGF-β. Both the glutathione (GSH) content and antioxidant activity of GST were enhanced by MSCs, while LPO levels were suppressed.

CONCLUSION

These findings provide further evidence that MSCs are valuable in treating RA, possibly due to their anti-inflammatory and anti-oxidative properties. Thus, MSCs have potential as a more effective therapeutic strategy for treating RA.

BRD3 Regulates the Inflammatory and Stress Response in Rheumatoid Arthritis Synovial Fibroblasts

BACKGROUND

Individual functions of members of the bromodomain (BRD) and extra-terminal (BET) protein family underlying the anti-inflammatory effects of BET inhibitors in rheumatoid arthritis (RA) are incompletely understood. Here, we aimed to analyze the regulatory functions of BRD3, an understudied member of the BET protein family, in RA synovial fibroblasts (FLS).

METHODS

BRD3 was silenced in FLS prior to stimulation with TNF. Alternatively, FLS were treated with I-BET. Transcriptomes were analyzed by RNA sequencing (RNAseq), followed by pathway enrichment analysis. We confirmed results for selective target genes by real-time PCR, ELISA, and Western blotting.

RESULTS

BRD3 regulates the expression of several cytokines and chemokines in FLS, and positively correlates with inflammatory scores in the RA synovium. In addition, RNAseq pointed to a profound role of BRD3 in regulating FLS proliferation, metabolic adaption, and response to stress, including oxidative stress, and autophagy.

CONCLUSIONS

BRD3 acts as an upstream regulatory factor that integrates the response to inflammatory stimuli and stress conditions in FLS and executes many functions of BET proteins that have previously been identified using pan-BET inhibitors.

Oxidative Stress Mediated Therapy in Patients with Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this meta-analysis is to explore all the available literature to obtain updated data about the potential use of antioxidants in the treatment of rheumatoid arthritis (RA) and its ability to reduce disease progression and cardiovascular risk.

METHODS

This systematic review and meta-analysis was performed strictly in accordance with the PRISMA guidelines. English and Chinese databases were searched with a retrieval time up to March 2023. These databases included the PubMed, Embase, Medline Complete, Web of Sciences and Cochrane Collaboration, Wanfang, China National Knowledge Infrastructure, and VIP databases. This literature search was formulated by the two researchers independently. The search strategy consists of reading, collecting the literature, and conducting the preliminary screening. After that, they provide the final selection of the literature according to the inclusion criteria and data extraction. Also, for all studies, the risk bias was assessed to evaluate the quality of the included references. The content of the risk assessment of bias included the following criteria: random allocation method, allocation plan hiding, blind method, completeness of result data, and selectivity of reporting of results, as well as other biases. The main outcomes were clinical efficiency of antioxidant therapy (C-reactive protein, DAS28 score, HAQ, Number of tender joints, etc.) and oxidative stress indicators (catalase, superoxide dismutase, or total antioxidant capacity).

RESULTS

We observed, in most of the studies, the small or moderate effects of antioxidant treatment. The mean effect size is 0.525, and that means that moderate effects were observed in 30 selected RCTs. Also, this effect is confirmed in the 1652 patients with RA with the mean confidence interval of 0.276 (lower limit) and 0.983 (upper limit). Cohen coefficient was calculated at 0.05.

CONCLUSION

The existing evidence is that antioxidants can reduce systemic and local oxidative stress and can reduce damage as the main agent involved in autoimmune diseases such as rheumatoid arthritis.

The histone acetyl transferases CBP and p300 regulate stress response pathways in synovial fibroblasts at transcriptional and functional levels

The activation of stress response pathways in synovial fibroblasts (SF) is a hallmark of rheumatoid arthritis (RA). CBP and p300 are two highly homologous histone acetyl transferases and writers of activating histone 3 lysine 27 acetylation (H3K27ac) marks. Furthermore, they serve as co-factors for transcription factors and acetylate many non-histone proteins. Here we showed that p300 but not CBP protein expression was down regulated by TNF and 4-hydroxynonenal, two factors that mimic inflammation and oxidative stress in the synovial microenvironment. We used existing RNA-sequencing data sets as a basis for a further in-depth investigation of individual functions of CBP and p300 in regulating different stress response pathways in SF. Pathway enrichment analysis pointed to a profound role of CBP and/ or p300 in regulating stress response-related gene expression, with an enrichment of pathways associated with oxidative stress, hypoxia, autophagy and proteasome function. We silenced CBP or p300, and performed confirmatory experiments on transcriptome, protein and functional levels. We have identified some overlap of CBP and p300 target genes in the oxidative stress response pathway, however, with several genes being regulated in opposite directions. The majority of stress response genes was regulated by p300, with a specific function of p300 in regulating hypoxia response genes and genes encoding proteasome subunits. Silencing of p300 suppressed proteasome enzymatic activities. CBP and p300 regulated autophagy on transcriptome and functional levels. Whereas CBP was indispensable for autophagy synthesis, silencing of p300 affected late-stage autophagy. In line with impaired autophagy and proteasome function, poly-ubiquitinated proteins accumulated after silencing of p300.

Global scientific trends update on macrophage polarization in rheumatoid arthritis: A bibliometric and visualized analysis from 2000 to 2022

The goal of this work was to use bibliometric analysis to help guide future research on macrophage polarization in RA. We looked for studies on macrophage polarization in RA published between January 1, 2000, and December 31, 2022, in the WoSCC database. Research trends and hotspots were shown and assessed using VOSviewer and CiteSpace. A total of 181 articles were gathered. Belgium was among the early adopters of the field. Chinese institutes have produced the most research. Researchers such as Angel Luis Corb, Amaya Puig-Kröger, and Lizbeth Estrada-Capetillo have made major contributions to the field. Frontiers in Immunology has published the most study findings. According to VOSviewer, the most investigated immune cells, biomarkers, and signaling pathways in the previous three years have been "T cells", "gm-csf", and "nf-κb" in that order. We discovered that the most often used terms in the previous three years were "pathway", "oxidative stress", "extracellular capsule" and "nlrp3 inflammasome" using Citespace. We emphasize these concepts in our findings, presenting the exact mechanisms of pathophysiology related to macrophage polarization in RA, as well as current breakthroughs in therapy strategies.

Therapeutic effects of columbianadin from Angelicae Pubescentis radix on the progression of collagen-induced rheumatoid aarthritis by regulating inflammation and oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Angelicae pubescentis radix (APR) has a long history in the treatment of rheumatoid arthritis (RA) in China. It has the effects of dispelling wind to eliminate dampness, removing arthralgia and stopping pain in the Chinese Pharmacopeia, but its mechanisms was remained unclear. Columbianadin (CBN), one of the main bioactive compounds of APR, was reported that it has many pharmacological effects including anti-inflammatory and immunosuppression. However, little study has been investigated therapeutic effect of CBN on RA.

AIM OF THE STUDY

A comprehensive strategy via incorporating pharmacodynamics, microbiomics, metabolomics, and multiple molecular biological methods was adopted to evaluated the therapeutic effects of CBN on collagen-induced arthritis (CIA) mice and explored the potential mechanisms.

MATERIALS AND METHODS

A variety of pharmacodynamic methods were used to evaluate the therapeutic effect of CBN on CIA mice. The microbial and metabolic characteristics of CBN anti-RA were obtained by metabolomics and 16S rRNA sequencing technology. The potential mechanism of CBN anti-RA was predicted through bioinformatics network analysis, and verified by a variety of molecular biology methods.

RESULTS

CBN effectively improve symptoms of rheumatoid arthritis in CIA mice, including paw swelling and arthritic scores. The inflammatory factors and oxidative stress markers were effectively regulated by the treatment of CBN. The fecal microbial communities and serum and urine metabolic compositions were significantly altered in CIA mice, CBN ameliorated the CIA-associated gut microbiota dysbiosis, and regulated the disturbance of serum and urine metabolome and reversed the changes of key CIA and gut microbiota-related metabolites. The acute toxicity test, results showed that the LD50 of CBN is greater than 2000 mg kg^-1, which confirmed the security of CBN.

CONCLUSIONS

CBN exert anti-RA effects from four perspectives: inhibiting inflammatory response, regulating oxidative stress, and improving changes in gut microbiota and metabolites. The JAK1/STAT3, NF-κB and Keap1/Nrf2 pathway may be an important mechanism for CBN's inflammatory response and oxidative stress activity. CBN could be considered as a potential anti-RA drug for further study.

Polymorphisms in microRNA binding site of SET8 regulate the risk of rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex, heterogeneous, progressive and long-term autoimmune disease characterized by symmetrical joint inflammation and bone erosion. The etiology of RA is unclear, but its pathogenesis is associated with oxidative stress and inflammatory cytokines. Single nucleotide polymorphisms (SNPs) in the microRNA (miRNA)-binding sites modify the development of rheumatic disease by regulating the expression of target genes. The present study investigated whether SNPs in the miRNA binding site in the 3' untranslated region (3'-UTR) of SET domain containing (lysine methyltransferase) 8 (SET8) and Keratin 81 (KRT81), namely rs16917496 and rs3660, respectively, were associated with the occurrence of RA. The polymerase chain reaction-ligase detection reaction assay showed that the distribution frequencies of the CC genotype (P=0.025) of SNP rs16917496 in SET8 were significantly higher in patients with RA than in healthy controls, which indicated that the CC genotype was associated with an increased risk of RA. SET8 expression in the blood samples of CC genotype carriers was lower than that of TT genotype carriers. Moreover, the CC genotype carriers exhibited higher reactive oxygen species (ROS) levels (1011.500±536.426 vs. 548.616±190.508, P=0.032) and lower interleukin-10 (IL-10) levels (P<0.001). The present study demonstrated that SNP rs16917496 in the 3'-UTR of SET8 was a predictor of RA risk and may regulate RA development by mediating expression of SET8, thereby regulating the levels of ROS and IL-10.

Fractionated whole body γ-irradiation aggravates arthritic severity via boosting NLRP3 and RANKL expression in adjuvant-induced arthritis model: the mitigative potential of ebselen

Rheumatoid arthritis (RA) is an autoimmune chronic inflammatory disease associated with oxidative stress that causes excruciating pain, discomfort, and joint destruction. Ebselen (EB), a synthesized versatile organo-selenium compound, protects cells from reactive oxygen species (ROS)-induced injury by mimicking glutathione peroxidase (GPx) action. This study aimed to investigate the antioxidant and anti-inflammatory effects of EB in an arthritic irradiated model. This goal was achieved by subjecting adjuvant-induced arthritis (AIA) rats to fractionated whole body γ-irradiation (2 Gy/fraction once per week for 3 consecutive weeks, for a total dose of 6 Gy) and treating them with EB (20 mg/kg/day, p.o) or methotrexate (MTX; 0.05 mg/kg; twice/week, i.p) as a reference anti-RA drug. The arthritic clinical signs, oxidative stress and antioxidant biomarkers, inflammatory response, expression of NOD-like receptor protein-3 (NLRP-3) inflammasome, receptor activator of nuclear factor κB ligand (RANKL), nuclear factor-κB (NF-κB), apoptotic indicators (caspase 1 and caspase 3), cartilage integrity marker (collagen-II), and histopathological examination of ankle joints were assessed. EB notably improved the severity of arthritic clinical signs, alleviated joint histopathological lesions, modulated oxidative stress and inflammation in serum and synovium, as well as reduced NLRP-3, RANKL, and caspase3 expression while boosting collagen-II expression in the ankle joints of arthritic and arthritic irradiated rats with comparable potency to MTX. Our findings suggest that EB, through its antioxidant and anti-inflammatory properties, has anti-arthritic and radioprotective properties in an arthritic irradiated model.

Role of reactive oxygen species and mitochondrial damage in rheumatoid arthritis and targeted drugs

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation, pannus formation, and bone and cartilage damage. It has a high disability rate. The hypoxic microenvironment of RA joints can cause reactive oxygen species (ROS) accumulation and mitochondrial damage, which not only affect the metabolic processes of immune cells and pathological changes in fibroblastic synovial cells but also upregulate the expression of several inflammatory pathways, ultimately promoting inflammation. Additionally, ROS and mitochondrial damage are involved in angiogenesis and bone destruction, thereby accelerating RA progression. In this review, we highlighted the effects of ROS accumulation and mitochondrial damage on inflammatory response, angiogenesis, bone and cartilage damage in RA. Additionally, we summarized therapies that target ROS or mitochondria to relieve RA symptoms and discuss the gaps in research and existing controversies, hoping to provide new ideas for research in this area and insights for targeted drug development in RA.

The mammalian target of rapamycin contributes to synovial fibroblast pathogenicity in rheumatoid arthritis

Objectives

The mammalian target of Rapamycin (mTOR) is a metabolic master regulator of both innate and adaptive immunity; however, its exact role in stromal cell biology is unknown. In this study we explored the role of the mTOR pathway on Rheumatoid Arthritis synovial fibroblast (RASF) metabolism and activation and determined if crosstalk with the Hippo-YAP pathway mediates their effects.

Methods

Primary RA synovial fibroblasts (RASF) were cultured with TNFα alone or in combination with the mTOR inhibitor Rapamycin or YAP inhibitor Verteporfin. Chemokine production, matrix metalloproteinase (MMP) production, and adhesion marker expression were quantified by real-time PCR, ELISA, and/or Flow Cytometry. Invasion assays were performed using Transwell invasion chambers, while wound repair assays were used to assess RASF migration. Cellular bioenergetics was assessed using the Seahorse XFe96 Analyzer. Key metabolic genes (GLUT-1, HK2, G6PD) were measured using real-time PCR. Reanalysis of RNA-Seq analysis was performed on RA (n = 151) and healthy control (HC) (n = 28) synovial tissue biopsies to detect differential gene and pathway expression. The expression of YAP was measured by Western Blot.

Results

Transcriptomic analysis of healthy donor and RA synovial tissue revealed dysregulated expression of several key components of the mTOR pathway in RA. Moreover, the expression of phospho-ribosomal protein S6 (pS6), the major downstream target of mTOR is specifically increased in RA synovial fibroblasts compared to healthy tissue. In the presence of TNFα, RASF display heightened phosphorylation of S6 and are responsive to mTOR inhibition via Rapamycin. Rapamycin effectively alters RASF cellular bioenergetics by inhibiting glycolysis and the expression of rate limiting glycolytic enzymes. Furthermore, we demonstrate a key role for mTOR signaling in uniquely mediating RASF migratory and invasive mechanisms, which are significantly abrogated in the presence of Rapamycin. Finally, we report a significant upregulation in several genes involved in the Hippo-YAP pathway in RA synovial tissue, which are predicted to converge with the mTOR pathway. We demonstrate crosstalk between the mTOR and YAP pathways in mediating RASF invasive mechanism whereby Rapamycin significantly abrogates YAP expression and YAP inhibition significantly inhibits RASF invasiveness.

Conclusion

mTOR drives pathogenic mechanisms in RASF an effect which is in part mediated via crosstalk with the Hippo-YAP pathway.

Polyene phosphatidylcholine ameliorates synovial inflammation: involvement of PTEN elevation and glycolysis suppression

BACKGROUND

Synovial inflammation, characterized by the activation of synovial fibroblasts (SFs), is a crucial factor to drive the progression of rheumatoid arthritis (RA). Polyene phosphatidylcholine (PPC), the classic hepatoprotective drug, has been reported to ameliorate arthritis in animals. However, the molecular mechanism remains poorly understood. METHODS AND RESULTS: Using in vitro primary synovial fibroblast (SFs) culture system, we revealed that phosphatase and tension homolog deleted on chromosome 10 (PTEN), a tumor suppressor, mediates the anti-inflammatory effect of PPC in lipopolysaccharide (LPS)-stimulated primary SFs. PPC decreased the production of TNF-α and IL-6 production while elevating the level of IL-10 and TGF-β. Furthermore, PPC up-regulated the expression of PTEN, but inhibited the expression of p-AKT (ser473) and PI3K-p85α. Moreover, pre-treatment of SF1670 (the inhibitor of PTEN) or 740Y-P (the agonist of AKT/PI3K pathways) partially abrogated the anti-inflammatory effect of PPC. In addition, PPC could inhibit the expression of GLUT4, a key transporter of glucose that fuels the glycolysis, which is accompanied by the expression downregualtion of glycolytic enzymes PFKFB3 and PKM2. Furthermore, PPC could reduce ROS production and mitochondrial membrane potential in LPS-stimulated SFs and MH7A cell line.

CONCLUSION

The present study supported that PPC can alleviate synovial inflammation, which involves in the elevation of PTEN and blockage of glycolysis.

LncRNA RNA XIST binding to GATA1 contributes to rheumatoid arthritis through its effects on proliferation of synovial fibroblasts and angiogenesis via regulation of CCN6

This study explored the role of the long non-coding RNA (lncRNA) XIST (X-inactive specific transcript) as a driver of RA pathogenesis, with a particular focus on the ability of this lncRNA to interact with GATA1 and CCN6. The GSE83147and GSE181614 datasets were downloaded for analysis. XIST and CCN6 expression were assessed in synovial fibroblasts (SFs) and in both normal cartilage samples and those from RA patients, with the relationship between XIST and CCN6 additionally being examined. XIST and CCN6 were respectively knocked down or overexpressed in SFs to establish their regulatory roles in these cells in the context of RA. Further studies of the regulatory interplay between XIST, GATA1, and CCN6 were then performed through RNA immunoprecipitation, RNA pull-down, gain-of-function, loss-of-function, and luciferase reporter assays. In addition, RA model rats were established and used to measure the production of TNF-α, IL-6, and IL-8 and to subject tissues from these animals to histopathological examination. RA patient synovial tissues and SFs exhibited XIST and CCN6 upregulation. The knockdown of XIST suppressed SF migratory, proliferative, invasive, and angiogenic activity, while CCN6 knockdown partially reversed the ability of XIST to influence these phenotypic outcomes in vitro and in vivo. XIST bound to GATA1 within SFs, thus promoting enhanced CCN6 transcription. Knocking down XIST alleviated RA-related pathological damage, synovial injury, and inflammatory response induction in rats. The binding of XIST to GATA1 leads to CCN6 upregulation, driving RA pathogenesis by altering SF proliferation and angiogenic activity, suggesting that this pathway may represent a viable target for therapeutic intervention.

Male infertility and somatic health - insights into lipid damage as a mechanistic link

Over the past decade, mounting evidence has shown an alarming association between male subfertility and poor somatic health, with substantial evidence supporting the increased incidence of oncological disease, cardiovascular disease, metabolic disorders and autoimmune diseases in men who have previously received a subfertility diagnosis. This paradigm is concerning, but might also provide a novel window for a crucial health reform in which the infertile phenotype could serve as an indication of potential pathological conditions. One of the major limiting factors in this association is the poor understanding of the molecular features that link infertility with comorbidities across the life course. Enzymes involved in the lipid oxidation process might provide novel clues to reconcile the mechanistic basis of infertility with incident pathological conditions. Building research capacity in this area is essential to enhance the early detection of disease states and provide crucial information about the disease risk of offspring conceived through assisted reproduction.

Rheumatoid arthritis and mitochondrial homeostasis: The crossroads of metabolism and immunity

Rheumatoid arthritis is an autoimmune disease characterized by chronic symmetric synovial inflammation and erosive bone destruction. Mitochondria are the main site of cellular energy supply and play a key role in the process of energy metabolism. They possess certain self-regulatory and repair capabilities. Mitochondria maintain relative stability in number, morphology, and spatial structure through biological processes, such as biogenesis, fission, fusion, and autophagy, which are collectively called mitochondrial homeostasis. An imbalance in the mitochondrial homeostatic environment will affect immune cell energy metabolism, synovial cell proliferation, apoptosis, and inflammatory signaling. These biological processes are involved in the onset and development of rheumatoid arthritis. In this review, we found that in rheumatoid arthritis, abnormal mitochondrial homeostasis can mediate various immune cell metabolic disorders, and the reprogramming of immune cell metabolism is closely related to their inflammatory activation. In turn, mitochondrial damage and homeostatic imbalance can lead to mtDNA leakage and increased mtROS production. mtDNA and mtROS are active substances mediating multiple inflammatory pathways. Several rheumatoid arthritis therapeutic agents regulate mitochondrial homeostasis and repair mitochondrial damage. Therefore, modulation of mitochondrial homeostasis would be one of the most attractive targets for the treatment of rheumatoid arthritis.

The role of oxidative stress in the development of knee osteoarthritis: A comprehensive research review

Knee osteoarthritis (KOA) is one of the most common degenerative diseases, and its core feature is the degeneration and damage of articular cartilage. The cartilage degeneration of KOA is due to the destruction of dynamic balance caused by the activation of chondrocytes by various factors, with oxidative stress playing an important role in the pathogenesis of KOA. The overproduction of reactive oxygen species (ROS) is a result of oxidative stress, which is caused by a redox process that goes awry in the inherent antioxidant defence system of the human body. Superoxide dismutase (SOD) inside and outside chondrocytes plays a key role in regulating ROS in cartilage. Additionally, synovitis is a key factor in the development of KOA. In an inflammatory environment, hypoxia in synovial cells leads to mitochondrial damage, which leads to an increase in ROS levels, which further aggravates synovitis. In addition, oxidative stress significantly accelerates the telomere shortening and ageing of chondrocytes, while ageing promotes the development of KOA, damages the regulation of redox of mitochondria in cartilage, and stimulates ROS production to further aggravate KOA. At present, there are many drugs to regulate the level of ROS, but these drugs still need to be developed and verified in animal models of KOA. We discuss mainly how oxidative stress plays a part in the development of KOA. Although the current research has achieved some results, more research is needed.

Inflammatory markers S100A8/A9 and metabolic alteration for evaluating signs of early phase toxicity of anticancer agent treatment

Anticancer agents can cause various side effects, including tissue damages/inflammatory reactions. Drug-responsive biomarkers are essential for evaluating drug toxicity in disease processes. S100 calcium-binding proteins A8/A9 (S100A8/A9) are highly expressed in neutrophils and monocytes/macrophages accumulated at inflammatory sites and are known to be related to tissue damage/inflammation; however, their response to drug toxicity has not been reported. Herein, we investigated the effects of anticancer agents (doxorubicin, cisplatin, and docetaxel) on S100A8/A9 gene expression profiles in four representative tissues (heart, kidney, liver, and lung) in normal C57BL/6J mice. Both S100A8/A9 expression was transiently or time-dependently elevated in four tissues within 48 h after dosing of the three anticancer agents under toxicity-inducing conditions. S100A8/A9 patterns differed among agents and tissues. This result suggests that S100A8/A9 is useful for evaluating anticancer agent-induced tissue damage. Metabolomic analysis revealed that some metabolites showed temporal patterns similar to that of S100A8/A9 expression. The amounts of fumarate (doxorubicin-treated heart), tyrosine (cisplatin-treated kidney), acetylcarnosine (doxorubicin-treated liver), and 2-phosphoglycerate (docetaxel-treated lung) showed similar patterns to that of S100A8/A9 expression. Although these metabolites showed different behaviors between tissues and serum, they may be useful marker candidates for evaluating anticancer agent-induced tissue damage at an earlier stage after dosing.

Interplay of Environmental, Individual and Genetic Factors in Rheumatoid Arthritis Provocation

In this review, we explore systemization of knowledge about the triggering effects of non-genetic factors in pathogenic mechanisms that contribute to the development of rheumatoid arthritis (RA). Possible mechanisms involving environmental and individual factors in RA pathogenesis were analyzed, namely, infections, mental stress, sleep deprivation ecology, age, perinatal and gender factors, eating habits, obesity and smoking. The non-genetic factors modulate basic processes in the body with the impact of these factors being non-specific, but these common challenges may be decisive for advancement of the disease in the predisposed body at risk for RA. The provocation of this particular disease is associated with the presence of congenital loci minoris resistentia. The more frequent non-genetic factors form tangles of interdependent relationships and, thereby, several interdependent external factors hit one vulnerable basic process at once, either provoking or reinforcing each other. Understanding the specific mechanisms by which environmental and individual factors impact an individual under RA risk in the preclinical stages can contribute to early disease diagnosis and, if the factor is modifiable, might be useful for the prevention or delay of its development.

CLP1 is a Prognosis-Related Biomarker and Correlates With Immune Infiltrates in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, heterogeneous autoimmune disease with a high disability rate that seriously affects society and individuals. However, there is a lack of effective and reliable diagnostic markers and therapeutic targets. In this study, we identified diagnostic markers of RA based on RNA modification and explored its role as well as degree of immune cell infiltration. We used the gene expression profile data of three synovial tissues (GSE55235, GSE55457, GSE77298) from the Gene Expression Omnibus (GEO) database and the gene of 5 RNA modification genes (including m6A, m1A, m5C, APA, A-1), combined with cluster analysis, identified four RNA modifiers closely related to RA (YTHDC1, LRPPRC, NOP2, and CLP1) and five immune cells namely T cell CD8, CD4 memory resting, T cells regulatory (Tregs) Macrophages M0, and Neutrophils. Based on the LASSO regression algorithm, hub genes and immune cell prediction models were established respectively in RA and a nomogram based on the immune cell model was built. Around 4 key RNA modification regulator genes, miRNA-mRNA, mRNA-TF networks have been established, and GSEA-GO, KEGG-GSEA enrichment analysis has been carried out. Finally, CLP1 was established as an effective RA diagnostic marker, and was highly positively correlated with T cells follicular helper (Tfh) infiltration. On the other hand, highly negatively correlated with the expression of mast cells. In short, CLP1 may play a non-negligible role in the onset and development of RA by altering immune cell infiltration, and it is predicted to represent a novel target for RA clinical diagnosis and therapy.

The Role of Reactive Oxygen Species in the Rheumatoid Arthritis-Associated Synovial Microenvironment

Rheumatoid arthritis (RA) is an inflammatory disease that begins with a loss of tolerance to modified self-antigens and immune system abnormalities, eventually leading to synovitis and bone and cartilage degradation. Reactive oxygen species (ROS) are commonly used as destructive or modifying agents of cellular components or they act as signaling molecules in the immune system. During the development of RA, a hypoxic and inflammatory situation in the synovium maintains ROS generation, which can be sustained by increased DNA damage and malfunctioning mitochondria in a feedback loop. Oxidative stress caused by abundant ROS production has also been shown to be associated with synovitis in RA. The goal of this review is to examine the functions of ROS and related molecular mechanisms in diverse cells in the synovial microenvironment of RA. The strategies relying on regulating ROS to treat RA are also reviewed.

Mitochondrial Dysfunction and Oxidative Stress in Rheumatoid Arthritis

Control of excessive mitochondrial oxidative stress could provide new targets for both preventive and therapeutic interventions in the treatment of chronic inflammation or any pathology that develops under an inflammatory scenario, such as rheumatoid arthritis (RA). Increasing evidence has demonstrated the role of mitochondrial alterations in autoimmune diseases mainly due to the interplay between metabolism and innate immunity, but also in the modulation of inflammatory response of resident cells, such as synoviocytes. Thus, mitochondrial dysfunction derived from several danger signals could activate tricarboxylic acid (TCA) disruption, thereby favoring a vicious cycle of oxidative/mitochondrial stress. Mitochondrial dysfunction can act through modulating innate immunity via redox-sensitive inflammatory pathways or direct activation of the inflammasome. Besides, mitochondria also have a central role in regulating cell death, which is deeply altered in RA. Additionally, multiple evidence suggests that pathological processes in RA can be shaped by epigenetic mechanisms and that in turn, mitochondria are involved in epigenetic regulation. Finally, we will discuss about the involvement of some dietary components in the onset and progression of RA.

Cellular metabolic adaptations in rheumatoid arthritis and their therapeutic implications

Activation of endothelium and immune cells is fundamental to the initiation of autoimmune diseases such as rheumatoid arthritis (RA), and it results in trans-endothelial cell migration and synovial fibroblast proliferation, leading to joint destruction. In RA, the synovial microvasculature is highly dysregulated, resulting in inefficient oxygen perfusion to the synovium, which, along with the high metabolic demands of activated immune and stromal cells, leads to a profoundly hypoxic microenvironment. In inflamed joints, infiltrating immune cells and synovial resident cells have great requirements for energy and nutrients, and they adapt their metabolic profiles to generate sufficient energy to support their highly activated inflammatory states. This shift in metabolic capacity of synovial cells enables them to produce the essential building blocks to support their proliferation, activation and invasiveness. Furthermore, it results in the accumulation of metabolic intermediates and alteration of redox-sensitive pathways, affecting signalling pathways that further potentiate the inflammatory response. Importantly, the inflamed synovium is a multicellular tissue, with cells differing in their metabolic requirements depending on complex cell-cell interactions, nutrient supply, metabolic intermediates and transcriptional regulation. Therefore, understanding the complex interplay between metabolic and inflammatory pathways in synovial cells in RA will provide insight into the underlying mechanisms of disease pathogenesis.

Oxidative Stress and 4-hydroxy-2-nonenal (4-HNE): Implications in the Pathogenesis and Treatment of Aging-related Diseases

Oxidative stress plays an important role in the development of aging-related diseases by accelerating the lipid peroxidation of polyunsaturated fatty acids in the cell membrane, resulting in the production of aldehydes, such as malondialdehyde and 4-hydroxy-2-nonenal (4-HNE) and other toxic substances. The compound 4-HNE forms adducts with DNA or proteins, disrupting many cell signaling pathways including the regulation of apoptosis signal transduction pathways. The binding of proteins to 4-HNE (4-HNE-protein) acts as an important marker of lipid peroxidation, and its increasing concentration in brain tissues and fluids because of aging, ultimately gives rise to some hallmark disorders, such as neurodegenerative diseases (Alzheimer's and Parkinson's diseases), ophthalmic diseases (dry eye, macular degeneration), hearing loss, and cancer. This review aims to describe the physiological origin of 4-HNE, elucidate its toxicity in aging-related diseases, and discuss the detoxifying effect of aldehyde dehydrogenase and glutathione in 4-HNE-driven aging-related diseases.

The Pathophysiology of The Antiphospholipid Syndrome: A Perspective From The Blood Coagulation System

The antiphospholipid syndrome (APS), a systemic autoimmune disease characterized by a hypercoagulability associated to vascular thrombosis and/or obstetric morbidity, is caused by the presence of antiphospholipid antibodies such as lupus anticoagulant, anti-β-2-glycoprotein 1, and/or anticardiolipin antibodies. In the obstetrical APS, antiphospholipid antibodies induce the production of proinflammatory cytokines and tissue factor by placental tissues and recruited neutrophils. Moreover, antiphospholipid antibodies activate the complement system which, in turn, induces a positive feedback leading to recruitment of neutrophils as well as activation of the placenta. Activation of these cells triggers myometrial contractions and cervical ripening provoking the induction of labor. In thrombotic and obstetrical APS, antiphospholipid antibodies activate endothelial cells, platelets, and neutrophils and they may alter the multimeric pattern and concentration of von Willebrand factor, increase the concentration of thrombospondin 1, reduce the inactivation of factor XI by antithrombin, increase the activation of factor XII, and reduce the activity of tissue plasminogen activator with the subsequent production of plasmin. All these effects result in less permeable clots, denser, thinner, and with more branched fibrin fibers which are more difficult to lysate. As a consequence, thrombosis, the defining clinical criterion of APS, complicates the clinical course of the patient.

Role of Mitochondria in Physiology of Chondrocytes and Diseases of Osteoarthritis and Rheumatoid Arthritis

PURPOSE OF REVIEW

Mitochondria are recognized to be one of the most important organelles in chondrocytes for their role in triphosphate (ATP) generation through aerobic phosphorylation. Mitochondria also participate in many intracellular processes involving modulating reactive oxygen species (ROS), responding to instantaneous hypoxia stress, regulating cytoplasmic transport of calcium ion, and directing mitophagy to maintain the homeostasis of individual chondrocytes.

DESIGNS

To summarize the specific role of mitochondria in chondrocytes, we screened related papers in PubMed database and the search strategy is ((mitochondria) AND (chondrocyte)) AND (English [Language]). The articles published in the past 5 years were included and 130 papers were studied.

RESULTS

In recent years, the integrity of mitochondrial structure has been regarded as a prerequisite for normal chondrocyte survival and defect in mitochondrial function has been found in cartilage-related diseases, such as osteoarthritis (OA) and rheumatoid arthritis (RA). However, the understanding of mitochondria in cartilage is still largely limited. The mechanism on how the changes in mitochondrial structure and function directly lead to the occurrence and development of cartilage-related diseases remains to be elusive.

CONCLUSION

This review aims to summarize the role of mitochondria in chondrocytes under the physiological and pathological changes from ATP generation, calcium homeostasis, redox regulation, mitophagy modulation, mitochondria biogenesis to immune response activation. The enhanced understanding of molecular mechanisms in mitochondria might offer some new cues for cartilage remodeling and pathological intervention.

Treatment with coenzyme Q10, omega-3-polyunsaturated fatty acids and their combination improved bioenergetics and levels of coenzyme Q9 and Q10 in skeletal muscle mitochondria in experimental model of arthritis

Rheumatoid arthritis (RA) and its animal model adjuvant arthritis (AA) are inflammatory diseases characterized by chronic inflammation, systemic oxidative stress and disturbed mitochondrial bioenergetics of skeletal muscle. The present study aimed to evaluate the effects of coenzyme Q10 - CoQ10 (100 mg/kg b.w.), omega-3-polyunsaturated fatty acids - omega-3-PUFA (400 mg/kg b.w.) and their combined treatment in AA on impaired skeletal muscle mitochondrial bioenergetics, inflammation and changes in levels CoQ9 and CoQ10 in plasma. Markers of inflammation (C-reactive protein, monocyte-chemotactic protein-1), antioxidant capacity of plasma, respiratory chain parameters of skeletal muscle mitochondria and concentrations of CoQ9 and CoQ10 in plasma and in muscle tissue were estimated. Treatment of the arthritic rats with CoQ10, omega-3-PUFA alone and in combination partially reduced markers of inflammation and increased antioxidant capacity of plasma, significantly increased concentrations of coenzyme Q in mitochondria and improved mitochondrial function in the skeletal muscle. Combined treatment has similar effect on the mitochondrial function as monotherapies; however, it has affected inflammation and antioxidant status more intensively than monotherapies. Long-term supplementary administration of coenzyme Q10 and omega-3-PUFA and especially their combination is able to restore the impaired mitochondrial bioenergetics and antioxidant status in AA.

New potential therapeutic approaches targeting synovial fibroblasts in rheumatoid arthritis

Synovial cells play a key role in joint destruction during chronic inflammation. In particular, activated synovial fibroblasts (SFs) undergo intrinsic alterations leading to an aggressive phenotype mediating cartilage destruction and bone erosion in rheumatoid arthritis (RA). Recent research has revealed a number of targets to control arthritogenic changes in SFs. Therefore, identification of SF phenotypes, control of epigenetic changes, modulation of cellular functions, or regulation of the activity of cation channels and different signaling pathways has been investigated. Although many of these approaches have shown efficacy in vitro and in animal models of RA, further research is needed to select the most relevant targets for drug development. This review is focused on the role of SFs as a potential strategy to discover novel therapeutic targets in RA aimed at preserving joint architecture and function.

The Efficacy of Antioxidative Stress Therapy on Oxidative Stress Levels in Rheumatoid Arthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Objective

To explore the efficacy of antioxidative stress therapy on oxidative stress levels in rheumatoid arthritis (RA) by a systematic review and meta-analysis of randomized controlled trials.

Methods

Chinese and English databases such as PubMed, Embase, China National Knowledge Infrastructure (CNKI), and China Biomedical Literature were searched, mainly searching for clinical randomized controlled trials of antioxidant therapy for rheumatoid arthritis. The search time is from the establishment of the database to July 2021. Two researchers independently carried out literature search, screening, and data extraction. The bias risk tool provided by the Cochrane Collaboration was used to evaluate the bias risk of all the included literature, and the RevMan 5.3 software was used for meta-analysis.

Results

A total of 24 RCTs (28 records) and 1277 participants were included. The time span of randomized controlled trials (RCTs) is from 1986 to 2020. These RCTs involve 14 types of antioxidants or antioxidant therapies, and these therapies have varying degrees of improvement on oxidative stress in RA patients. The summary results showed that the MDA in the experiment group is lower (SMD -0.82, 95% CI -1.35 to -0.28, P = 0.003). The difference of TAC, SOD, NO, GPx, CAT, and GSH between two groups was of no statistical significance (TAC (SMD 0.27, 95% CI -0.21 to 0.75, P = 0.27), SOD (SMD 0.12, 95% CI -0.16 to 0.40, P = 0.41), NO (SMD -2.03, 95% CI -4.22 to 0.16, P = 0.07), GPx (SMD 0.24, 95% CI -0.07 to 0.54, P = 0.13), CAT (SMD 2.95, 95% CI -2.6 to 8.51, P = 0.30), and GSH (SMD 2.46, 95% CI -0.06 to 4.98, P = 0.06)). For adverse events, the summary results showed that the difference was of no statistical significance (RR 1.16, 95% CI 0.79 to 1.71, P = 0.45). In addition, antioxidant therapy has also shown improvement in clinical efficacy indexes (number of tender joints, number of swollen joints, DAS28, VAS, and HAQ) and inflammation indexes (ESR, CRP, TNF-α, and IL6) for RA patients.

Conclusion

The existing evidence shows potential benefits, mainly in reducing MDA and increasing TAC and GSH in some subgroups. However, more large samples and higher quality RCTs are needed to provide high-quality evidence, so as to provide more clinical reference information for the antioxidant treatment of RA.

Platelet mitochondrial respiration and coenzyme Q10 could be used as new diagnostic strategy for mitochondrial dysfunction in rheumatoid diseases

Introduction

Rheumatoid arthritis (RA) is a chronic inflammatory autoimunne disorder affecting both small and large synovial joints, leading to their destruction. Platelet biomarkers are involved in inflammation in RA patients. Increased circulating platelet counts in RA patients may contribute to platelet hyperactivity and thrombosis. In this pilot study we evaluated platelet mitochondrial bioenergy function, CoQ₁₀ levels and oxidative stress in RA patients.

Methods

Twenty-one RA patients and 19 healthy volunteers participated in the study. High resolution respirometry (HRR) was used for analysis of platelet mitochondrial bioenergetics. CoQ₁₀ was determined by HPLC method; TBARS were detected spectrophotometrically.

Results

Slight dysfunction in platelet mitochondrial respiration and reduced platelet CoQ₁₀ levels were observed in RA patients compared with normal controls.

Conclusions

The observed decrease in platelet CoQ₁₀ levels may lead to platelet mitochondrial dysfunction in RA diseases. Determination of platelet mitochondrial function and platelet CoQ₁₀ levels could be used as new diagnostic strategies for mitochondrial bioenergetics in rheumatoid diseases.

Sinapic Acid Attenuates Rheumatoid Arthritis Through Reducing Inflammation and Oxidative Stress by Downregulating IκB Kinase

Sinapic acid (SA) was reported to protect against inflammation in various types of diseases. However, the role of SA in rheumatoid arthritis remains unclear. This study was designed to investigate the role of SA on rheumatoid arthritis. Rheumatoid arthritis mouse model was established by collagen immunization [collagen-induced arthritis (CIA)]. Histological analysis of articular cartilage tissue was carried out by hematoxylin and eosin (H&E) staining. Serum concentrations of tumor necrosis factor alpha and interleukin 6 were determined through enzyme-linked immunosorbent assay (ELISA). Oxidative damage indexes such as superoxide dismutase activity, malondialdehyde detection, glutathione detection, and catalase were determined by biochemical analysis. The protein levels of related genes were determined using Western blot. In CIA model, SA treatment attenuated paw swelling and clinical score of arthritis, attenuated articular cartilage tissues edema and infiltration of inflammatory cells, suppressed inflammatory cytokines release, and attenuated oxidative damage indexes. Mechanically, SA suppressed immune responses through inhibiting the IκB kinase (IKKs). SA attenuates rheumatoid arthritis through reducing inflammation and oxidative stress by downregulating IKKs.

Developmental Angiogenesis Requires the Mitochondrial Phenylalanyl-tRNA Synthetase

Background: Mitochondrial aminoacyl-tRNA synthetases (mtARSs) catalyze the binding of specific amino acids to their cognate tRNAs and play an essential role in the synthesis of proteins encoded by mitochondrial DNA. Defects in mtARSs have been linked to human diseases, but their tissue-specific pathophysiology remains elusive. Here we examined the role of mitochondrial phenylalanyl-tRNA synthetase (FARS2) in developmental angiogenesis and its potential contribution to the pathogenesis of cardiovascular disease.

Methods: Morpholinos were injected into fertilized zebrafish ova to establish an in vivo fars2 knock-down model. A visualization of the vasculature was achieved by using Tg (fli1: EGFP)^y1 transgenic zebrafish. In addition, small interference RNAs (siRNAs) were transferred into human umbilical vein endothelial cells (HUVECs) to establish an in vitro FARS2 knock-down model. Cell motility, proliferation, and tubulogenesis were determined using scratch-wound CCK8, transwell-based migration, and tube formation assays. In addition, mitochondria- and non-mitochondria-related respiration were evaluated using a Seahorse XF24 analyzer and flow cytometry assays. Analyses of the expression levels of transcripts and proteins were performed using qRT-PCR and western blotting, respectively.

Results: The knock-down of fars2 hampered the embryonic development in zebrafish and delayed the formation of the vasculature in Tg (fli1: EGFP)^y1 transgenic zebrafish. In addition, the siRNA-mediated knock-down of FARS2 impaired angiogenesis in HUVECs as indicated by decreased cell motility and tube formation capacity. The knock-down of FARS2 also produced variable decreases in mitochondrial- and non-mitochondrial respiration in HUVECs and disrupted the regulatory pathways of angiogenesis in both HUVECs and zebrafish.

Conclusion: Our current work offers novel insights into angiogenesis defects and cardiovascular diseases induced by FARS2 deficiency.

Does membrane curvature elastic energy play a role in mediating oxidative stress in lipid membranes?

The effects of oxidative stress on cells are associated with a wide range of pathologies. Oxidative stress is predominantly initiated by the action of reactive oxygen species and/or lipoxygenases on polyunsaturated fatty acid containing lipids. The downstream products are oxidised phospholipids, bioactive aldehydes and a range of Schiff base by-products between aldehydes and lipids, or other biomacromolecules. In this review we assess the impact of oxidative stress on lipid membranes, focusing on the changes that occur to the curvature preference (lipid spontaneous curvature) and elastic properties of membranes, since these biophysical properties modulate phospholipid homeostasis. Studies show that the lipid products of oxidative stress reduce stored curvature elastic energy in membranes. Based upon this observation, we hypothesize that the effects of oxidative stress on lipid membranes will be reduced by compounds that increase stored curvature elastic energy. We find a strong correlation appears across literature studies that we have reviewed, such that many compounds like vitamin E, Curcumin, Coenzyme Q10 and vitamin A show behaviour consistent with this hypothesis. Finally, we consider whether age-related changes in lipid composition represent the homeostatic response of cells to compensate for the accumulation of in vivo lipid oxidation products.

Repurposing metformin for covid-19 complications in patients with type 2 diabetes and insulin resistance

Understanding the exact role of current drugs in Covid-19 disease is essential in the era of global pandemics. Metformin which prescribed as the first-line treatment of type 2 diabetes has beneficial effects on Sars-cov2 infection. These effects are including regulation of immune system, Renin-Angiotensin System and Dipeptidyl Peptidase 4 function in Covid-19 infection. It also activates ACE2, the main receptor of Sars-cov2, in the epithelial cells of respiratory tissue through AMPK signaling and subsequently decreases the rate of viral adhesion. Metformin also declines the adherence of Sars-cov2 to DPP4 (the other receptor of the virus) on T cells. Hence, regulatory effects of metformin on membranous ACE2, and DPP4 can modulate immune reaction against Sars-cov2. Also, immunometabolic effects of metformin on inflammatory cells impair hyper-reactive immune response against the virus through reduction of glycolysis and propagation of mitochondrial oxidation. Metformin also decreases platelet aggravation and risk of thrombosis. In this article, we argue that metformin has beneficial effects on Covid-19 infection in patients with type 2 diabetes and insulin resistance. This opinion should be investigated in future clinical trials.

Efficacy of berberine in treatment of rheumatoid arthritis: From multiple targets to therapeutic potential

Rheumatoid arthritis is a systemic autoimmune disorder involved in persistent synovial inflammation. Berberine is a nature-derived alkaloid compound with multiple pharmacological activities in different pathologies, including RA. Recent experimental studies have clarified several determinant cellular and molecular targets of BBR in RA, and provided novel evidence supporting the promising therapeutic potential of BBR to combat RA. In this review, we recapitulate the therapeutic potential of BBR and its mechanism of action in ameliorating RA, and discuss the modulation of gut microbiota by BBR during RA. Collectively, BBR might be a promising lead drug with multi-functional activities for the therapeutic strategy of RA.

Yoga improves mitochondrial health and reduces severity of autoimmune inflammatory arthritis: A randomized controlled trial

BACKGROUND

Oxidative stress (OS) and mitochondrial alterations have been implicated in the pathogenesis of rheumatoid arthritis (RA). Various environmental triggers like air pollutants, smoking, unhealthy social habits and sedentary lifestyle induce OS, which may compromise mitochondrial integrity. This trial was designed to explore the effect of 8-weeks yoga practice on mitochondrial health and disease severity in an active RA group compared with a usual-care control group.

METHODS

A total of 70 subjects were randomized into two groups: yoga group and non-yoga group. Mitochondrial health was assessed by calculation of mitochondrial DNA copy number (mtDNA-CN), OS markers, mitochondrial activity, mitochondrial membrane potential (ΔΨm), circadian rhythm markers and transcripts associated with mitochondrial integrity: AMPK, TIMP-1, KLOTHO, SIRT-1, and TFAM. Parameters of disease activity and disability quotient were also assessed by disease activity score - erythrocyte sedimentation rate (DAS28-ESR) and health assessment questionnaire-disability index (HAQ-DI), respectively.

RESULTS

In yoga group, there was a significant upregulation of mtDNA-CN, mitochondrial activity markers, ΔΨm, and transcripts that maintain mitochondrial integrity after 8-weeks of yoga. There was optimization of OS markers, and circadian rhythm markers post 8-weeks practice of yoga. Yoga group participants showed significant improvements in DAS28-ESR (p < 0.05) and HAQ-DI (p < 0.05) over the non-yoga group.

CONCLUSION

Adoption of yoga by RA patients holds the key to enhance mitochondrial health, improve circadian rhythm markers, OS marker regulation, upregulation of transcripts that maintain mitochondrial integrity, reduce disease activity and its associated consequences on health outcome and hence can be beneficial as an adjunct therapy.

Reactive Oxygen Species in Autoimmune Cells: Function, Differentiation, and Metabolism

Accumulated reactive oxygen species (ROS) directly contribute to biomacromolecule damage and influence various inflammatory responses. Reactive oxygen species act as mediator between innate and adaptive immune cells, thereby influencing the antigen-presenting process that results in T cell activation. Evidence from patients with chronic granulomatous disease and mouse models support the function of ROS in preventing abnormal autoimmunity; for example, by supporting maintenance of macrophage efferocytosis and T helper 1/T helper 2 and T helper 17/ regulatory T cell balance. The failure of many anti-oxidation treatments indicates that ROS cannot be considered entirely harmful. Indeed, enhancement of ROS may sometimes be required. In a mouse model of rheumatoid arthritis (RA), absence of NOX2-derived ROS led to higher prevalence and more severe symptoms. In patients with RA, naïve CD4⁺ T cells exhibit inhibited glycolysis and enhanced pentose phosphate pathway (PPP) activity, leading to ROS exhaustion. In this "reductive" state, CD4⁺ T cell immune homeostasis is disrupted, triggering joint destruction, together with oxidative stress in the synovium.

Evaluation of Oxidative Stress before and after Using Laser and Photoactivation Therapy as Adjuvant of Non-Surgical Periodontal Treatment in Patients with Rheumatoid Arthritis

(1) Background: The aim of this split-mouth design study was to analyze the clinical periodontal indexes and oxidative stress markers in gingival crevicular fluid modifications after three periodontal disease treatment possibilities (scaling and root planning-SRP; SRP and diode laser-L; SRP and photodynamic therapy-PDT). (2) Methods: The study was conducted on 52 patients: systemically healthy subjects with periodontal disease-non-RA (n = 26); and test group (n = 26) subjects with rheumatoid arthritis and periodontal disease-RA. Clinical periodontal measurements (probing depth-PD; Löe and Silness gingival index-GI; papillary bleeding index-PBI; and periodontal community index of treatment needs-CPITN) and oxidative stress markers (8-hydroxy-2'-deoxyguanosine (8-OHdG) and 4 hydroxynonenal (4-HNE)) were analyzed at baseline (T0), after three sessions of periodontal treatment (T1), and 6 months after treatment (T2). (3) Results: Periodontal therapy improved clinical periodontal measurements and oxidative stress markers in both analyzed groups, with supplementary benefits for laser- and PDT-treated periodontal pockets. (4) Conclusions: The analyzed oxidative stress markers decreased significantly following non-surgical periodontal therapy in both rheumatoid arthritis and systemically healthy patients. All the periodontal disease treatment possibilities analyzed in this study offered clinical and paraclinical improvements; however, the association of laser with SRP and photodisinfection with SRP yielded the best clinical and paraclinical outcomes when compared to SRP alone.

Transcriptome-wide association study identifies susceptibility genes for rheumatoid arthritis

Objective

To identify rheumatoid arthritis (RA)-associated susceptibility genes and pathways through integrating genome-wide association study (GWAS) and gene expression profile data.

Methods

A transcriptome-wide association study (TWAS) was conducted by the FUSION software for RA considering EBV-transformed lymphocytes (EL), transformed fibroblasts (TF), peripheral blood (NBL), and whole blood (YBL). GWAS summary data was driven from a large-scale GWAS, involving 5539 autoantibody-positive RA patients and 20,169 controls. The TWAS-identified genes were further validated using the mRNA expression profiles and made a functional exploration.

Results

TWAS identified 692 genes with P_TWAS values < 0.05 for RA. CRIPAK (P^EL = 0.01293, P^TF = 0.00038, P^NBL = 0.02839, P^YBL = 0.0978), MUT (P^EL = 0.00377, P^TF = 0.00076, P^NBL = 0.00778, P^YBL = 0.00096), FOXRED1 (P^EL = 0.03834, P^TF = 0.01120, P^NBL = 0.01280, P^YBL = 0.00583), and EBPL (P^EL = 0.00806, P^TF = 0.03761, P^NBL = 0.03540, P^YBL = 0.04254) were collectively expressed in all the four tissues/cells. Eighteen genes, including ANXA5, AP4B1, ATIC (P_TWAS = 0.0113, downregulated expression), C12orf65, CMAH, PDHB, RUNX3 (P_TWAS = 0.0346, downregulated expression), SBF1, SH2B3, STK38, TMEM43, XPNPEP1, KIAA1530, NUFIP2, PPP2R3C, RAB24, STX6, and TLR5 (P_TWAS = 0.04665, upregulated expression), were validated with integrative analysis of TWAS and mRNA expression profiles. TWAS-identified genes functionally involved in endoplasmic reticulum organization, regulation of cytokine production, TNF signaling pathway, immune response-regulating signaling pathway, regulation of autophagy, etc.

Conclusion

We identified multiple candidate genes and pathways, providing novel clues for the genetic mechanism of RA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02419-9.

Human mesenchymal stromal cell source and culture conditions influence extracellular vesicle angiogenic and metabolic effects on human endothelial cells in vitro

BACKGROUND

Mesenchymal stem/stromal cell (MSC)-derived extracellular vesicles (EVs) are a possible cell-free alternative to MSCs because they retain the regenerative potential of MSCs, while still mitigating some of their limitations (such as the possible elicitation of host immune responses). The promotion and restoration of angiogenesis, however, is an important component in treating trauma-related injuries, and has not been fully explored with EVs. Herein, we describe the effects of monolayer adipose-derived EVs, spheroid adipose-derived EVs (SAd-EVs), monolayer bone marrow-derived EVs (MBM-EVs), and spheroid bone marrow-derived EVs (SBM-EVs) on human umbilical vein endothelial cell (HUVEC) tube formation and mitochondrial respiration.

METHODS

The successful isolation of EVs derived from adipose MSCs or bone marrow MSCs in monolayer or spheroid cultures was confirmed by NanoSight (particle size distribution) and Western blot (surface marker expression). The EV angiogenic potential was measured using a 24-hour HUVEC tube formation assay. The EV effects on HUVEC mitochondrial function were evaluated using the Seahorse respirometer machine.

RESULTS

The number of junctions, branches, and the average length of branches formed at 24 hours of tube formation were significantly affected by cell and culture type; overall adipose-derived EVs outperformed bone marrow-derived EVs, and spheroid-derived EVs outperformed monolayer-derived EVs. Additionally, adipose-derived EVs resulted in significantly increased HUVEC mitochondrial maximal respiration and adenosine triphosphate (ATP) production, while only MBM-EVs negatively impacted HUVEC proton leak.

CONCLUSION

Adipose-derived EVs promoted HUVEC tube formation significantly more than bone marrow-derived EVs, while also maximizing HUVEC mitochondria function. Results demonstrate that, as with MSC therapies, it is possible to tailor EV culture and production to optimize therapeutic potential.

LEVEL OF EVIDENCE

Basic or Foundational Research.

Gene expression signatures of target tissues in type 1 diabetes, lupus erythematosus, multiple sclerosis, and rheumatoid arthritis

Autoimmune diseases are typically studied with a focus on the immune system, and less attention is paid to responses of target tissues exposed to the immune assault. We presently evaluated, based on available RNA sequencing data, whether inflammation induces similar molecular signatures at the target tissues in type 1 diabetes, systemic lupus erythematosus, multiple sclerosis, and rheumatoid arthritis. We identified confluent signatures, many related to interferon signaling, indicating pathways that may be targeted for therapy, and observed a high (>80%) expression of candidate genes for the different diseases at the target tissue level. These observations suggest that future research on autoimmune diseases should focus on both the immune system and the target tissues, and on their dialog. Discovering similar disease-specific signatures may allow the identification of key pathways that could be targeted for therapy, including the repurposing of drugs already in clinical use for other diseases.