Mitochondrial dysfunction in rheumatoid arthritis: A comprehensive analysis by integrating gene expression, protein-protein interactions and gene ontology data

Urinary total superoxide dismutase activity is low in rheumatoid patients, and its low levels are associated with higher DAS28 scores

AIM

Rheumatoid factor and anti-citrullinated peptide antibodies are generally used to diagnose rheumatoid arthritis (RA). However, these antibodies are negative in 15-20 % of RA cases. This study aimed to investigate new biomarkers that can be used in diagnosing RA and evaluating disease activity.

METHODS

This study included 99 RA patients and 94 healthy volunteers. Modified Disease Activity Score28 (DAS28) erythrocyte sedimentation rate (ESR) was used for disease activity score. Thiol/disulfide molecules were measured using an automatic spectrophotometric method, and ischemia-modified albumin was measured using an albumin-cobalt binding test. A spectrophotometer calculated urinary and serum total superoxide dismutase (SOD) activities at 420 nm wavelength.

RESULTS

In the RA group, serum IMA level was higher (unstandardized beta [B]: 5.552, Odds Ratio [OR]: 250.1, CI 95 %: 1.29-48219.1, p: .040), and urinary total SOD activities were significantly lower (B: 2.640 OR: .071, CI 95 %: .027-.192, p < 0.0001) than in the control group. A cut-off value of 5.06 for urinary total SOD was found to have a sensitivity of 97.9 % and a specificity of 97 % in distinguishing RA patients from healthy controls (AUC [95 %Cl] = .986 [.967-1.000], p < 0.001). Urinary total SOD activity was significantly lower in the RA subgroup with high disease activity compared to the groups with moderate disease activity (B: .954, OR: 2.596, CI 95 %: 1.104-6.103, p: .029) and low disease activity (B: 1.251, OR: 3.494, CI 95 %: 1.143-10.678, p: .028).

CONCLUSION

This study showed that urinary total SOD activity has high sensitivity and specificity in distinguishing RA patients from healthy controls and that RA patients with higher DAS28 ESR activity scores have lower urinary total SOD activity.

Synovial fluid o-tyrosine is a potential biomarker for autoimmune-driven rheumatoid arthritis

INTRODUCTION/OBJECTIVES

The aim of the present study was to identify key amino acid (AA) pathways in osteoarthritis (OA) and autoimmune-driven rheumatoid arthritis (RA), as AAs have emerged as potential biomarkers for the detection of degenerative joint diseases. It was hypothesized that we would detect distinct metabolic pathways activated in OA and RA due to different degrees of inflammation.

METHOD

Samples of synovial fluid (SF) and infrapatellar Hoffa's fat pad (IFP) were collected from end-stage knee OA (n = 10) and RA patients (n = 10), and from non-inflammatory controls (n = 5). Metabolites were analyzed utilizing a liquid chromatography high-resolution mass spectrometry approach, followed by univariate and multivariate statistical testing and pathway analysis by MetaboAnalyst. Receiver operating characteristic analysis was used to examine diagnostic values.

RESULTS

SF results identified o-tyrosine as a promising biomarker for distinguishing RA patients from OA patients and controls, and cystine, cysteine, and methionine separating OA patients from controls. Regarding IFPs, β-alanine could have diagnostic value to discriminate RA and OA. The present data indicate alterations in metabolic pathways, such as cysteine and methionine metabolism in RA and OA SFs compared to control SF, selenocompound metabolism in RA vs. OA SFs, and pyrimidine metabolism in RA vs. OA IFPs.

CONCLUSIONS

The identified nitrogen compounds, particularly o-tyrosine, and AA metabolism pathways have potential as novel diagnostic and therapeutic targets for degenerative joint diseases. Key Points • Synovial fluid o-tyrosine can distinguish rheumatoid arthritis from osteoarthritis and control. • Synovial fluid cystine, cysteine, and methionine separate osteoarthritis from control. • β-Alanine in intra-articular fat has diagnostic value between rheumatoid arthritis and osteoarthritis. • A routine measurement of o-tyrosine would be useful in the future as an indicator of rheumatoid arthritis.

Synovial Fluid as a Crucial Component of the Joint Microenvironment in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease closely associated with synovial tissue proliferation, pannus formation in small joints such as the hands, wrists, and feet, cartilage destruction, and systemic complications such as pulmonary, cardiovascular, neurological, and skeletal muscle lesions, glucocorticoid-induced osteoporosis and infections. The importance of confirming the diagnosis and determining local activity is given to the study of synovial fluid. A deep understanding of the pathological process in the joint in RA, characterized by changes in autoreactive CD4+ T cells, B cells, macrophages, inflammatory cytokines, chemokines, and autoantibodies, has now been achieved, although much remains to be explored. This article provides an updated overview of the pathogenesis of RA, revealing even more therapeutic targets for the intra-articular pathological process.

Regulation of reactive oxygen species and the role of mitochondrial apoptotic-related genes in rheumatoid arthritis

Previous research suggests mitochondrial apoptosis alleviates rheumatoid arthritis (RA), but the role of mitochondrial apoptosis-related genes (MARGs) is unclear. Urgent exploration of RA-related mitochondrial apoptosis biomarkers is needed. Gene Expression Ontology (GEO)-derived RA datasets were used to identify differentially expressed genes (DEGs) compared to normal controls, intersected with MARGs to obtain differentially expressed mitochondrial apoptosis-related genes (DE-MARGs). Three ML algorithms screened diagnostic biomarkers. A nomogram was built and validated by receiver operating characteristic (ROC) analysis. Gene Set Enrichment Analysis (GSEA), regulatory network, and drug prediction explored biomarker mechanisms. Finally, key cells analysis included clustering, type annotation, pseudo-temporal study, and interaction, focusing on validated biomarker expression in those cells. A total of 147 DE-MARGs linked to energy & ROS metabolism were identified. Four validated biomarkers (MRPS10, EEF2, HSPA9, TUFM) formed a new RA diagnostic model. Moreover, GSEA linked them to oxidative phosphorylation. YY1 regulates EEF2, HSPA9, MRPS10; FOXO3 regulates EEF2, TUFM. Drugs like Nonoxynol-9, Nedocromil, Gadobutrol target these biomarkers. In addition, biomarkers are expressed in plasmablasts, with CD74 as a key receptor binding multiple ligands. RA biomarkers (MRPS10, EEF2, HSPA9, TUFM) linked to energy & ROS, progression tied to AMPK/mTOR, CD74-MIF crucial. Study advances RA pathogenesis knowledge, supporting clinical diagnosis.

Mitochondrial dysfunction in platelets from severe trauma patients - A prospective case-control study

INTRODUCTION

Trauma-induced coagulopathy (TIC) refers to an abnormal coagulation process, an imbalance between coagulation and fibrinolysis due to several pathological factors, such as haemorrhage and tissue injury. Platelet activation and subsequent clot formation are associated with mitochondrial activity, suggesting a possible role for mitochondria in TIC. Comprehensive studies of mitochondrial dysfunction in platelets from severe trauma patients have not yet been performed.

METHODS

In this prospective case-control study, patients with severe trauma (ISS≥16) had venous blood samples taken at arrival to the Emergency Unit of a Level 1 Trauma Centre. Mitochondrial functional measurements (Oxygraph-2k, Oroboros) were performed to determine oxygen consumption in different respiratory states, the H2O2 production and extramitochondrial Ca2+ movements. In addition, standard laboratory and coagulation tests, viscoelastometry (ClotPro) and aggregometry (Multiplate) were performed. Measurements data were compared with age and sex matched healthy control patients.

RESULTS

Severe trauma patients (n = 113) with a median age of 38 years (IQR, 20-51), a median ISS of 28 (IQR, 20-48) met our inclusion criteria. Oxidative phosphorylation in platelet mitochondria from severe trauma patients significantly decreased compared to controls (34.7 ± 8.8 pmol/s/mL vs. 48.0 ± 19.7 pmol/s/mL). The mitochondrial H2O2 production significantly increased and greater endogenous Ca2+ release was found in the polytrauma group. Consistent with these results, clotting time (CT) increased while maximum clot firmness (MCF) decreased with the EX-test and FIB-test in severe trauma samples. Multiplate aggregometry showed significantly decreased ADP-test (38 ± 12 AUC vs. 112 ± 14 AUC) and ASPI test (78 ± 22 AUC vs. 84 ± 28 AUC) also tended to decrease in mitochondria of polytrauma patients as compared with controls. Significant strong correlation has been demonstrated between mitochondrial OxPhos and MCF while it was negatively correlated with ISS (R2=0.448, P˂0.05), INR, CT and lactate level of patients.

CONCLUSIONS

The present study revealed that severe trauma is associated with platelet mitochondrial dysfunction resulting in reduced ATP synthesis and impaired extramitochondrial Ca2+ movement. These factors are required for platelet activation, recruitment and clot stability likely thus, platelet mitochondrial dysfunction contributes to the development of TIC.

The chemical composition of Diwu YangGan capsule and its potential inhibitory roles on hepatocellular carcinoma by microarray-based transcriptomics

The Traditional Chinese Medicine compound preparation known as Diwu Yanggan capsule (DWYG) can effectively hinder the onset and progression of hepatocellular carcinoma (HCC), which is recognized worldwide as a significant contributor to fatalities associated with cancer. Nevertheless, the precise mechanisms implicated have remained ambiguous. In present study, the model of HCC was set up by the 2-acetylaminofluorene (2-AAF)/partial hepatectomy (PH) in rats. To confirm the differentially expressed genes (DEGs) identified in the microarray analysis, real-time quantitative reverse transcription PCR (qRT-PCR) was conducted. In the meantime, the liquid chromatography-quadrupole time of flight mass spectrometry (LC-QTOF-MS/MS) was employed to characterize the component profile of DWYG. Consequently, the DWYG treatment exhibited the ability to reverse 51 variation genes induced by 2-AAF/PH. Additionally, there was an overlap of 54 variation genes between the normal and model groups. Upon conducting RT-qPCR analysis, it was observed that the expression levels of all genes were increased by 2-AAF/PH and subsequently reversed after DWYG treatment. Notably, the fold change of expression levels for all genes was below 0.5, with 3 genes falling below 0.25. Moreover, an investigation was conducted to determine the signaling pathway that was activated/inhibited in the HCC group and subsequently reversed in the DWYG group. Moreover, the component profile of DWYG encompassed a comprehensive compilation of 206 compounds that were identified or characterized. The findings of this study elucidated the potential alleviative mechanisms of DWYG in the context of HCC, thereby holding significant implications for its future clinical utilization and widespread adoption.

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.

A cellular overview of immunometabolism in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease, characterized by a breakdown of immune tolerance and the development of autoantibodies against nucleic self-antigens. Immunometabolism is a rapidly expanding scientific field investigating the metabolic programming of cells of the immune system. During the normal immune response, extensive reprogramming of cellular metabolism occurs, both to generate adenosine triphosphate and facilitate protein synthesis, and also to manage cellular stress. Major pathways upregulated include glycolysis, oxidative phosphorylation, the tricarboxylic acid cycle and the pentose phosphate pathway, among others. Metabolic reprogramming also occurs to aid resolution of inflammation. Immune cells of both patients with SLE and lupus-prone mice are characterized by metabolic abnormalities resulting in an altered functional and inflammatory state. Recent studies have described how metabolic reprogramming occurs in many cell populations in SLE, particularly CD4+ T cells, e.g. favouring a glycolytic profile by overactivation of the mechanistic target of rapamycin pathway. These advances have led to an increased understanding of the metabolic changes affecting the inflammatory profile of T and B cells, monocytes, dendritic cells and neutrophils, and how they contribute to autoimmunity and SLE pathogenesis. In the current review, we aim to summarize recent advances in the field of immunometabolism involved in SLE and how these could potentially lead to new therapeutic strategies in the future.

Increased n-6 Polyunsaturated Fatty Acids Indicate Pro- and Anti-Inflammatory Lipid Modifications in Synovial Membranes with Rheumatoid Arthritis

Emerging evidence suggests that fatty acids (FAs) and their lipid mediator derivatives can induce both beneficial and detrimental effects on inflammatory processes and joint degradation in osteoarthritis (OA) and autoimmune-driven rheumatoid arthritis (RA). The present study characterized the detailed FA signatures of synovial membranes collected during knee replacement surgery of age- and gender-matched OA and RA patients (n = 8/diagnosis). The FA composition of total lipids was determined by gas chromatography and analyzed with univariate and multivariate methods supplemented with hierarchical clustering (HC), random forest (RF)-based classification of FA signatures, and FA metabolism pathway analysis. RA synovium lipids were characterized by reduced proportions of shorter-chain saturated FAs (SFAs) and elevated percentages of longer-chain SFAs and monounsaturated FAs, alkenyl chains, and C20 n-6 polyunsaturated FAs compared to OA synovium lipids. In HC, FAs and FA-derived variables clustered into distinct groups, which preserved the discriminatory power of the individual variables in predicting the RA and OA inflammatory states. In RF classification, SFAs and 20:3n-6 were among the most important FAs distinguishing RA and OA. Pathway analysis suggested that elongation reactions of particular long-chain FAs would have increased relevance in RA. The present study was able to determine the individual FAs, FA groups, and pathways that distinguished the more inflammatory RA from OA. The findings suggest modifications of FA elongation and metabolism of 20:4n-6, glycerophospholipids, sphingolipids, and plasmalogens in the chronically inflamed RA synovium. These FA alterations could have implications in lipid mediator synthesis and potential as novel diagnostic and therapeutic tools.

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 Involvement of Glucose and Lipid Metabolism Alteration in Rheumatoid Arthritis and Its Clinical Implication

Obviously, immune cells like T cells and macrophages play a major role in rheumatoid arthritis (RA). On one hand, the breakdown of immune homeostasis directly induces systemic inflammation; on the other hand, these cells initiate and perpetuate synovitis and tissue damages through the interaction with fibroblast-like synoviocytes (FLS). In recent years, the pathological link between metabolic disorders and immune imbalance has received increasing attention. High energy demand of immune cells leads to the accumulation of metabolic byproducts and inflammatory mediators. They act on various metabolism-sensitive signal pathways as well as relevant transcription factors, such as HIF-1α, and STATs. These molecular events will impact RA-related effectors like circulating immune cells and joint-resident cells in return, allowing the continuous progression of systemic inflammation, arthritic manifestations, and life-threatening complications. In other words, metabolic complications are secondary pathological factors for the progression of RA. Therefore, the status of energy metabolism may be an important indicator to evaluate RA severity, and in-depth explorations of the mechanisms underlying the mystery of how RA-related metabolic disorders develop will provide useful clues to further clarify the etiology of RA, and inspire the discovery of new anti-rheumatic targets. This article reviews the latest research progress on the interactions between immune and metabolism systems in the context of RA. Great importance is attached to the changes in certain pathways controlling both immune and metabolism functions during RA progression.

Mitochondria and sensory processing in inflammatory and neuropathic pain

Rheumatic diseases, such as osteoarthritis and rheumatoid arthritis, affect over 750 million people worldwide and contribute to approximately 40% of chronic pain cases. Inflammation and tissue damage contribute to pain in rheumatic diseases, but pain often persists even when inflammation/damage is resolved. Mechanisms that cause this persistent pain are still unclear. Mitochondria are essential for a myriad of cellular processes and regulate neuronal functions. Mitochondrial dysfunction has been implicated in multiple neurological disorders, but its role in sensory processing and pain in rheumatic diseases is relatively unexplored. This review provides a comprehensive understanding of how mitochondrial dysfunction connects inflammation and damage-associated pathways to neuronal sensitization and persistent pain. To provide an overall framework on how mitochondria control pain, we explored recent evidence in inflammatory and neuropathic pain conditions. Mitochondria have intrinsic quality control mechanisms to prevent functional deficits and cellular damage. We will discuss the link between neuronal activity, mitochondrial dysfunction and chronic pain. Lastly, pharmacological strategies aimed at reestablishing mitochondrial functions or boosting mitochondrial dynamics as therapeutic interventions for chronic pain are discussed. The evidence presented in this review shows that mitochondria dysfunction may play a role in rheumatic pain. The dysfunction is not restricted to neuronal cells in the peripheral and central nervous system, but also includes blood cells and cells at the joint level that may affect pain pathways indirectly. Pre-clinical and clinical data suggest that modulation of mitochondrial functions can be used to attenuate or eliminate pain, which could be beneficial for multiple rheumatic diseases.

Mitochondrial Dysfunction Affects the Synovium of Patients with Rheumatoid Arthritis and Osteoarthritis Differently

There is growing evidence regarding the role of mitochondrial dysfunction in osteoarthritis (OA) and rheumatoid arthritis (RA). However, quantitative comparison of synovial mitochondrial derangements in these main arthritis forms is missing. A prospective clinical study was conducted on adult patients undergoing knee surgery. Patients were allocated into RA and OA groups based on disease-specific clinical scores, while patients without arthritis served as controls. Synovial samples were subjected to high-resolution respirometry to analyze mitochondrial functions. From the total of 814 patients, 109 cases were enrolled into the study (24 RA, 47 OA, and 38 control patients) between 1 September 2019 and 31 December 2021. The decrease in complex I-linked respiration and dyscoupling of mitochondria were characteristics of RA patients, while both arthritis groups displayed reduced OxPhos activity compared to the control group. However, no significant difference was found in complex II-related activity between the OA and RA groups. The cytochrome C release and H₂O₂ formation were increased in both arthritis groups. Mitochondrial dysfunction was present in both arthritis groups; however, to a different extent. Consequently, mitochondrial protective agents may have major benefits for arthritis patients. Based on our current study, we recommend focusing on respiratory complex I in rheumatoid arthritis research.

Ameliorative effect of cerium oxide nanoparticles against Freund's complete adjuvant-induced arthritis

Aim: To assess the mechanistic effects of cerium oxide nanoparticles (CONPs) on Freund's complete adjuvant (FCA)-induced rheumatoid arthritis in rats. Methods: CONPs were characterized and evaluated in vitro (RAW 264.7 macrophages) and in vivo (FCA-induced rheumatoid arthritis model). Results:In vitro treatment with CONPs significantly reduced lipopolysaccharide-induced oxidative stress (as evident from dichlorodihydrofluorescein diacetate staining), diminished mitochondrial stress (as observed with tetraethylbenzimidazolylcarbocyanine iodide staining) and reduced superoxide radicals. In vivo, CONPs exhibited anti-rheumatoid arthritis activity, as evident from results of paw volume, x-ray, clinical scoring, levels of cytokines (IL-17, IL-1β, TNF-α and TGF-β1) and histology. Conclusion: We provide preclinical proof that CONPs may be a novel futuristic nanoparticle-based approach for therapy of rheumatoid arthritis.

Mitochondrial dysfunction in trauma-related coagulopathy - Is there causality? - Study protocol for a prospective observational study

Hemorrhage control often poses a great challenge for clinicians due to trauma-induced coagulopathy (TIC). The pathogenesis of TIC is not completely revealed; however, growing evidence attributes a central role to altered platelet biology. The activation of thrombocytes and subsequent clot formation are highly energetic processes being tied to mitochondrial activity, and the inhibition of the electron transport chain (ETC) impedes on thrombogenesis, suggesting the potential role of mitochondria in TIC. Our present study protocol provides a guide to quantitatively characterize the derangements of mitochondrial functions in TIC. One hundred eleven severely injured (Injury Severity Score ≥16), bleeding trauma patients with an age of 18 or greater will be included in this prospective observational study. Patients receiving oral antiplatelet agents including cyclooxygenase-1 or adenosine diphosphate receptor inhibitors (aspirin, clopidogrel, prasugrel, and ticagrelor) will be excluded from the final analysis. Hemorrhage will be confirmed and assessed with computer tomography. Conventional laboratory markers of hemostasis such as prothrombin time and international normalized ratio (INR) will be measured and rotational thromboelastometry (ROTEM) will be performed directly upon patient arrival. Platelets will be isolated from venous blood samples and subjected to high-resolution fluororespirometry (Oxygraph-2k, Oroboros Instruments, Innsbruck, Austria) to evaluate the efficacy of mitochondrial respiration. Oxidative phosphorylation (OxPhos), coupling of the ETC, mitochondrial superoxide formation, mitochondrial membrane potential changes and extramitochondrial Ca2+-movement will be recorded. The association between OxPhos capacity of platelet mitochondria and numerical parameters of ROTEM aggregometry will constitute our primary outcome. The relation between OxPhos capacity and results of viscoelastic assays and conventional markers of hemostasis will serve as secondary outcomes. The association of the OxPhos capacity of platelet mitochondria upon patient arrival to the need for massive blood transfusion (MBT) and 24-hour mortality will constitute our tertiary outcomes. Mitochondrial dysfunction and its importance in TIC in are yet to be assessed for the deeper understanding of this common, life-threatening condition. Disclosure of mitochondria-mediated processes in thrombocytes may reveal new therapeutic targets in the management of hemorrhaging trauma patients, thereby leading to a reduction of potentially preventable mortality. The present protocol was registered to ClinicalTrials.gov on 12 August 2021, under the reference number NCT05004844.

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.

SARS-CoV-2 spike promotes inflammation and apoptosis through autophagy by ROS-suppressed PI3K/AKT/mTOR signaling

Background

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection-induced inflammatory responses are largely responsible for the death of novel coronavirus disease 2019 (COVID-19) patients. However, the mechanism by which SARS-CoV-2 triggers inflammatory responses remains unclear. Here, we aimed to explore the regulatory role of SARS-CoV-2 spike protein in infected cells and attempted to elucidate the molecular mechanism of SARS-CoV-2-induced inflammation.

Methods

SARS-CoV-2 spike pseudovirions (SCV-2-S) were generated using the spike-expressing virus packaging system. Western blot, mCherry-GFP-LC3 labeling, immunofluorescence, and RNA-seq were performed to examine the regulatory mechanism of SCV-2-S in autophagic response. The effects of SCV-2-S on apoptosis were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Western blot, and flow cytometry analysis. Enzyme-linked immunosorbent assay (ELISA) was carried out to examine the mechanism of SCV-2-S in inflammatory responses.

Results

Angiotensin-converting enzyme 2 (ACE2)-mediated SCV-2-S infection induced autophagy and apoptosis in human bronchial epithelial and microvascular endothelial cells. Mechanistically, SCV-2-S inhibited the PI3K/AKT/mTOR pathway by upregulating intracellular reactive oxygen species (ROS) levels, thus promoting the autophagic response. Ultimately, SCV-2-S-induced autophagy triggered inflammatory responses and apoptosis in infected cells. These findings not only improve our understanding of the mechanism underlying SARS-CoV-2 infection-induced pathogenic inflammation but also have important implications for developing anti-inflammatory therapies, such as ROS and autophagy inhibitors, for COVID-19 patients.

The Role of Cell Organelles in Rheumatoid Arthritis with Focus on Exosomes

Auto-immune diseases involved at least 25% of the population in wealthy countries. Several factors including genetic, epigenetic, and environmental elements are implicated in development of Rheumatoid Arthritis as an autoimmune disease. Autoantibodies cause synovial inflammation and arthritis, if left untreated or being under continual external stimulation, could result in chronic inflammation, joint injury, and disability. T- and B-cells, signaling molecules, proinflammatory mediators, and synovium-specific targets are among the new therapeutic targets. Exosomes could be employed as therapeutic vectors in the treatment of autoimmune diseases. Herein, the role of cell organelle particularly exosomes in Rheumatoid Arthritis had discussed and some therapeutic applications of exosome highlighted.

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.

Targeting Mitochondrial-Derived Reactive Oxygen Species in T Cell-Mediated Autoimmune Diseases

Mitochondrial dysfunction resulting in oxidative stress could be associated with tissue and cell damage common in many T cell-mediated autoimmune diseases. Autoreactive CD4 T cell effector subsets (Th1,Th17) driving these diseases require increased glycolytic metabolism to upregulate key transcription factors (TF) like T-bet and RORγt that drive differentiation and proinflammatory responses. However, research in immunometabolism has demonstrated that mitochondrial-derived reactive oxygen species (ROS) act as signaling molecules contributing to T cell fate and function. Eliminating autoreactive T cells by targeting glycolysis or ROS production is a potential strategy to inhibit autoreactive T cell activation without compromising systemic immune function. Additionally, increasing self-tolerance by promoting functional immunosuppressive CD4 T regulatory (Treg) cells is another alternative therapeutic for autoimmune disease. Tregs require increased ROS and oxidative phosphorylation (OxPhos) for Foxp3 TF expression, differentiation, and anti-inflammatory IL-10 cytokine synthesis. Decreasing glycolytic activity or increasing glutathione and superoxide dismutase antioxidant activity can also be beneficial in inhibiting cytotoxic CD8 T cell effector responses. Current treatment options for T cell-mediated autoimmune diseases such as Type 1 diabetes (T1D), multiple sclerosis (MS), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE) include global immunosuppression, antibodies to deplete immune cells, and anti-cytokine therapy. While effective in diminishing autoreactive T cells, they can also compromise other immune responses resulting in increased susceptibility to other diseases and complications. The impact of mitochondrial-derived ROS and immunometabolism reprogramming in autoreactive T cell differentiation could be a potential target for T cell-mediated autoimmune diseases. Exploiting these pathways may delay autoimmune responses in T1D.

Mitochondrial nanomedicine: Subcellular organelle-specific delivery of molecular medicines

As mitochondria network together to act as the master sensors and effectors of apoptosis, ATP production, reactive oxygen species management, mitophagy/autophagy, and homeostasis; this organelle is an ideal target for pharmaceutical manipulation. Mitochondrial dysfunction contributes to many diseases, for example, β-amyloid has been shown to interfere with mitochondrial protein import and induce apoptosis in Alzheimer's Disease while some forms of Parkinson's Disease are associated with dysfunctional mitochondrial PINK1 and Parkin proteins. Mitochondrial medicine has applications in the treatment of an array of pathologies from cancer to cardiovascular disease. A challenge of mitochondrial medicine is directing therapies to a subcellular target. Nanotechnology based approaches combined with mitochondrial targeting strategies can greatly improve the clinical translation and effectiveness of mitochondrial medicine. This review discusses mitochondrial drug delivery approaches and applications of mitochondrial nanomedicines. Nanomedicine approaches have the potential to drive the success of mitochondrial therapies into the clinic.

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.

Lipid, fatty acid, carnitine- and choline derivative profiles in rheumatoid arthritis outpatients with different degrees of periodontal inflammation

Rheumatoid arthritis (RA) and periodontitis are chronic inflammatory diseases with several pathogenic pathways in common. Evidence supports an association between the diseases, but the exact underlying mechanisms behind the connection are still under investigation. Lipid, fatty acid (FA) and metabolic profile alterations have been associated with several chronic inflammatory diseases, including RA and periodontitis. Mitochondria have a central role in regulating cellular bioenergetic and whole-body metabolic homeostasis, and mitochondrial dysfunction has been proposed as a possible link between the two disorders. The aim of this cross-sectional study was to explore whole-blood FA, serum lipid composition, and carnitine- and choline derivatives in 78 RA outpatients with different degrees of periodontal inflammation. The main findings were alterations in lipid, FA, and carnitine- and choline derivative profiles. More specifically, higher total FA and total cholesterol concentrations were found in active RA. Elevated phospholipid concentrations with concomitant lower choline, elevated medium-chain acylcarnitines (MC-AC), and decreased ratios of MC-AC and long-chain (LC)-AC were associated with prednisolone medication. This may indicate an altered mitochondrial function in relation to the increased inflammatory status in RA disease. Our findings may support the need for interdisciplinary collaboration within the field of medicine and dentistry in patient stratification to improve personalized treatment. Longitudinal studies should be conducted to further assess the potential impact of mitochondrial dysfunction on RA and periodontitis.

An original biomarker for the risk of developing cardiovascular diseases and their complications: Telomere length

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We studied a sample of patients with coronary heart disease.

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We analyzed the telomere length in this sample.

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We compared telomere length in patients and conventionally healthy study participants.

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Patients with coronary heart disease had shorter telomerestelomeres.

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These patients had an increased risk of cardiovascular complication.

Aim

The aim of this work was to study the effect of telomere length in the chromosomes of nuclear blood cells in individuals with coronary heart disease (CHD) on the development of cardiovascular complications (CVC).

Materials and methods

DNA was isolated from nuclear blood cells of 498 study participants. The telomere length was determined by real-time polymerase chain reaction. The investigation of each sample was repeated three times. Five years after the end of this study, a telephone survey of 119 patients with CHD was conducted in order to obtain data on the presence of CVC.

Results

According to the results obtained, a decrease in telomere length in patients with coronary heart disease increases the risk of subsequent development of cardiovascular complications.

Conclusion

Patients with coronary heart disease with shorter telomeres compared with conventionally healthy study participants had an increased risk of cardiovascular complications within 5 years after telomere analysis.

Differential mitochondrial genome in patients with Rheumatoid Arthritis

BACKGROUND

Mitochondria play an important role in cell survival, function and lineage differentiation. Changes in mitochondrial DNA (mtDNA) may control mitochondrial functions and thus may impart an alternative cellular state thereby leading to a disease condition in the body. Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease wherein immune cells become self-reactive causing joint inflammation, swelling and pain in patients. The changes in mtDNA may alter cellular functions thereby directing the immune cells towards an inflammatory phenotype in RA. Therefore, it becomes pertinent to identify changes in mtDNA sequence in immune cells of RA patients to understand the pathogenesis and progression of RA.

METHODS

mtDNA from peripheral blood mono-nuclear cells (PBMCs) of 23 RA patients and 17 healthy controls (HCs) were sequenced using next-generation sequencing (NGS). Further, single nucleotide polymorphisms (SNPs) and other variable changes in mtDNA hypervariable and coding regions, amino acid changes with a putative impact on disease, levels of heteroplasmy, copy number variations and haplogroup analysis in RA patients and HCs were analysed and compared to identify any association of mtDNA changes and RA disease.

RESULTS

A total of 382 single nucleotide mtDNA variants were observed, 91 (23.82%) were present in hypervariable region and 291 (76.18%) in coding region of patients and HC. The variant 513 GCA > ACA, with G present in HVR-III, known to control the mitochondrial translation function, was significantly present in RA patients. The CYTB gene had larger number of SNPs in HC samples while RNR2 was more variable in RA patients. A non-synonymous heteroplasmy in ND1 gene was found at a single nucleotide position 3533 in an increased number of RA patients as compared to the controls. A significant increase in mtDNA duplication and a higher frequency of the haplogroup U was also characteristic of RA. Also, the presence of SNPs in mitochondrial tRNA genes at two positions 12308 A > G and 15924 A > G were found to be pathogenic.

CONCLUSION

We herein observed an altered mtDNA sequence in immune cells of RA patients and thus a possible role of mitochondrial genome in the development of RA. The observed nucleotide changes in mtDNA control region, RNR2 gene, increased heteroplasmy and mtDNA duplication in RA patients may alter sites for transcription factor binding thereby influencing mtDNA gene expression, as well as copy numbers thereby affecting the mitochondrial proteins and their functions. These changes in mtDNA could be one of the probable reasons among many leading to the progression of RA.

[Danggui Niantong decoction induces apoptosis by activating Fas/caspase-8 pathway in rheumatoid arthritis fibroblast-like synoviocytes]

OBJECTIVE

To explore the effect of Danggui Niantong decoction (DGNTD) on cell apoptosis and TNF receptor super family 6 (Fas)/caspase-8 pathway in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS).

METHODS

FLS isolated from the synovial tissue of RA patients were cultured and identified using immunofluorescence staining. The cells were treated with 10% blank serum (blank control group), 10% sera containing low, moderate or high doses of DGNTD, or 20 μmol/mL KR-33493 (a Fas inhibitor) combined with 10% serum containing high-dose DGNTD. MTT assay was used to detect the proliferation of the cells after the treatments. Apoptosis of the cells was detected at 48 h in each group using Hoechst 33342 staining and flow cytometry with annexin V-FITC/PI staining. The mRNA and protein expressions of Fas, FADD, caspase-8 and caspase-3 in the cells at 48 h were detected using qPCR and Western blotting.

RESULTS

Immunofluorescence staining identified the cultured cells as FLS. Treatment with DGNTD-containing sera significantly inhibited the proliferation of FLS, and the inhibitory effects were enhanced as the dose and intervention time increased (P < 0.05). Hoechst 33342 staining and flow cytometry showed that the sera containing different doses of DGNTD significantly promoted apoptosis of FLS (P < 0.05). The expression levels of Fas, FADD, caspase-8, and caspase-3 at both mRNA and protein levels were significantly increased in the cells after treatment with different doses of DGNTD-containing sera (P < 0.05). The application of KR-33493 obviously reversed the effects of DGNTD on the FLS (P < 0.05).

CONCLUSIONS

DGNTD can induce apoptosis of the FLS by activating Fas/caspase-8 signaling pathway.