Nrf2–Keap1 pathway–mediated effects of resveratrol on oxidative stress and apoptosis in hydrogen peroxide–treated rheumatoid arthritis fibroblast‐like synoviocytes

Nrf2-mediated ferroptosis inhibition: a novel approach for managing inflammatory diseases

Inflammatory diseases, including psoriasis, atherosclerosis, rheumatoid arthritis, and ulcerative colitis, are characterized by persistent inflammation. Moreover, the existing treatments for inflammatory diseases only provide temporary relief by controlling symptoms, and treatments of unstable and expensive. Therefore, new therapeutic solutions are urgently needed to address the underlying causes or symptoms of inflammatory diseases. Inflammation frequently coincides with a high level of (reactive oxygen species) ROS activation, serving as a fundamental element in numerous physiological and pathological phenotypes that can result in serious harm to the organism. Given its pivotal role in inflammation, oxidative stress, and ferroptosis, ROS represents a focal node for investigating the (nuclear factor E2-related factor 2) Nrf2 pathway and ferroptosis, both of which are intricately linked to ROS. Ferroptosis is mainly triggered by oxidative stress and involves iron-dependent lipid peroxidation. The transcription factor Nrf2 targets several genes within the ferroptosis pathway. Recent studies have shown that Nrf2 plays a significant role in three key ferroptosis-related routes, including the synthesis and metabolism of glutathione/glutathione peroxidase 4, iron metabolism, and lipid processes. As a result, ferroptosis-related treatments for inflammatory diseases have attracted much attention. Moreover, drugs targeting Nrf2 can be used to manage inflammatory conditions. This review aimed to assess ferroptosis regulation mechanism and the role of Nrf2 in ferroptosis inhibition. Therefore, this review article may provide the basis for more research regarding the treatment of inflammatory diseases through Nrf2-inhibited ferroptosis.

Lung decellularized matrix-derived 3D spheroids: Exploring silicosis through the impact of the Nrf2/Bax pathway on myofibroblast dynamics

Silicosis is an occupational respiratory disease caused by long-term inhalation of high concentrations of free silica particles. Studies suggest that oxidative stress is a crucial initiator of silicosis fibrosis, and previous studies have linked the antioxidative stress transcription factor known as Nrf2 to fibrosis antagonism. Myofibroblasts play a pivotal role in tissue damage repair due to oxidative stress. Unlike physiological repair, myofibroblasts in fibrosis exhibit an apoptosis-resistant phenotype, continuously synthesising and secreting significant amounts of collagen and other extracellular matrices, which could be a direct cause of silicosis fibrosis. However, the relationship and mechanism of action between oxidative stress and myofibroblast apoptosis resistance remain unclear. In this study, a new 3D cell culture model using mice lung decellularised matrix particles and fibroblasts was developed, simulating the changes in myofibroblasts during the development of silicotic nodules. Western Blot results indicate that silica stimulation leads to increased collagen deposition and decreased apoptosis-related protein Bax and oxidative stress-related protein Nrf2 in the 3D spheroid model. Immunofluorescence experiments reveal co-localisation in their expression. In Nrf2 overexpressing spheroids, Bax exhibits significant upregulation. In the Nrf2 knockout spheroids, Bax is also significantly downregulated; after intervention with Bax inhibitors, a significant downregulation of Bax-induced apoptosis was also detected in the Nrf2-overexpressed spheroids. In contrast, Bax-induced apoptosis showed a significant upregulation trend in Nrf2-overexpressed spheroids after intervention with Bax agonists. The results demonstrate that the spheroid model can mimic the development process of silicotic nodules, and silica stimulation leads to an apoptosis-resistant phenotype in myofibroblasts in the model, acting through the Nrf2/Bax pathway. This research establishes a new methodology for silicosis study, identifies therapeutic targets for silicosis, and opens new avenues for studying the mechanisms of silicosis fibrosis.

Potential Role of Dietary Phenolic Compounds in the Prevention and Treatment of Rheumatoid Arthritis: Current Reports

Rheumatoid arthritis (RA) is a complex illness with both hereditary and environmental components. Globally, in 2019, 18 million people had RA. RA is characterized by persistent inflammation of the synovial membrane that lines the joints, cartilage loss, and bone erosion. Phenolic molecules are the most prevalent secondary metabolites in plants, with a diverse spectrum of biological actions that benefit functional meals and nutraceuticals. These compounds have received a lot of attention recently because they have antioxidant, anti-inflammatory, immunomodulatory, and anti-rheumatoid activity by modulating tumor necrosis factor, mitogen-activated protein kinase, nuclear factor kappa-light-chain-enhancer of activated B cells, and c-Jun N-terminal kinases, as well as other preventative properties. This article discusses dietary polyphenols, their pharmacological properties, and innovative delivery technologies for the treatment of RA, with a focus on their possible biological activities. Nonetheless, commercialization of polyphenols may be achievable only after confirming their safety profile and completing successful clinical trials.

Maternal exposure to hyperbaric oxygen at the preimplantation stages increases apoptosis and ectopic Cdx2 expression and decreases Oct4 expression in mouse blastocysts via Nrf2-Notch1 upregulation and Nf2 downregulation

BACKGROUND

The environmental oxygen tension has been reported to impact the blastocyst quality and cell numbers in the inner cell mass (ICM) during human and murine embryogenesis. While the molecular mechanisms leading to increased ICM cell numbers and pluripotency gene expression under hypoxia have been deciphered, it remains unknown which regulatory pathways caused the underweight fetal body and overweight placenta after maternal exposure to hyperbaric oxygen (HBO).

RESULTS

The blastocysts from the HBO-exposed pregnant mice revealed significantly increased signals of reactive oxygen species (ROS) and nuclear Nrf2 staining, decreased Nf2 and Oct4 expression, increased nuclear Tp53bp1 and active caspase-3 staining, and ectopic nuclear signals of Cdx2, Yap, and the Notch1 intracellular domain (N1ICD) in the ICM. In the ICM of the HBO-exposed blastocysts, both Nf2 cDNA microinjection and Nrf2 shRNA microinjection significantly decreased the ectopic nuclear expression of Cdx2, Tp53bp1, and Yap whereas increased Oct4 expression, while Nrf2 shRNA microinjection also significantly decreased Notch1 mRNA levels and nuclear expression of N1ICD and active caspase-3.

CONCLUSION

We show for the first time that maternal exposure to HBO at the preimplantation stage induces apoptosis and impairs ICM cell specification via upregulating Nrf2-Notch1-Cdx2 expression and downregulating Nf2-Oct4 expression.

Amelioration of inflammation through reduction of oxidative stress in rheumatoid arthritis by treating fibroblast-like synoviocytes (FLS) with DMF-loaded PLGA nanoparticles

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory condition, and Dimethyl fumarate (DMF) is known for inducing antioxidant enzymes and reducing reactive oxygen species (ROS). Fibroblast-like synoviocytes (FLS) contribute to joint damage by releasing interleukins (IL-1β, IL-6, and IL-8) in response to ROS. Given ROS's impact on FLS acquiring an invasive phenotype, our study explored the effects of poly lactic-co-glycolic acid (PLGA) nanoparticles containing DMF on the expression of the HO-1 enzyme and the inflammatory cytokines IL-1β, IL-6, and IL-8 in FLS cells.

METHODS

In this study, we evaluated and compared the impact of Free-DMF and PLGA-DMF, on the gene expression of the HO-1 and inflammatory cytokines (IL-1β, IL-6, and IL-8) in FLS cells derived from 13 patients with rheumatoid arthritis. qRT-PCR method was used to quantify the gene expression levels.

RESULTS

PLGA-DMF nanoparticles demonstrated a significant increase in HO-1 expression and a significant decrease in IL-1β gene expression. Also, a significant decrease in IL-6 gene expression was seen under the effect of Free-DMF. These results indicate the potential effectiveness of PLGA-DMF nanoparticles in reducing inflammation and improving rheumatoid arthritis symptoms.

DISCUSSION

According to the findings, PLGA-DMF nanoparticles are expected to be effective in reducing inflammation and improving the symptoms of rheumatoid arthritis. Also, further studies on other factors affected by oxidative stress such as cell invasion factors and survival factors after the effect of PLGA-DMF nanoparticle are recommended.

Astaxanthin-loaded alginate-chitosan gel beads activate Nrf2 and pro-apoptotic signalling pathways against oxidative stress

Oxidative stress (OS) plays a crucial role in disease development. Astaxanthin (ATX), a valuable natural compound, may reduce OS and serve as a treatment for diseases like neurodegenerative disorders and cancer. Nuclear factor-erythroid 2-related factor 2 (Nrf2) regulates antioxidant enzymes and OS management. We evaluated ATX's antioxidant activity via Alg-CS/ATX gel beads in vitro. ATX-encapsulated alginate-chitosan (Alg-CS/ATX) gel beads were synthesized and structurally/morphologically characterized by SEM, FT-IR, and XRD. Their biological effects were examined in human umbilical vein endothelial cells (HUVECs) treated with H2O2 through MTT assay, Annexin V/PI, cell cycle studies, and western blotting. Alg-CS effectively carried ATX, with high capacity and reduced pore size. Alg-CS/ATX displayed an 84% encapsulation efficiency, maintaining stability for 30 days. In vitro studies showed a 1.4-fold faster release at pH 5.4 than at neutral pH, improving ATX's therapeutic potential. HUVECs treated with Alg-CS/ATX showed enhanced viability via increased Nrf2 expression. Alg-CS gel beads exhibit significant potential as a biocompatible vehicle for delivering ATX to combat OS with considerable opportunity for clinical applications.

E-Stilbenes: General Chemical and Biological Aspects, Potential Pharmacological Activity Based on the Nrf2 Pathway

Stilbenes are phytoalexins, and their biosynthesis can occur through a natural route (shikimate precursor) or an alternative route (in microorganism cultures). The latter is a metabolic engineering strategy to enhance production due to stilbenes recognized pharmacological and medicinal potential. It is believed that in the human body, these potential activities can be modulated by the regulation of the nuclear factor erythroid derived 2 (Nrf2), which increases the expression of antioxidant enzymes. Given this, our review aims to critically analyze evidence regarding E-stilbenes in human metabolism and the Nrf2 activation pathway, with an emphasis on inflammatory and oxidative stress aspects related to the pathophysiology of chronic and metabolic diseases. In this comprehensive literature review, it can be observed that despite the broad number of stilbenes, those most frequently explored in clinical trials and preclinical studies (in vitro and in vivo) were resveratrol, piceatannol, pterostilbene, polydatin, stilbestrol, and pinosylvin. In some cases, depending on the dose/concentration and chemical nature of the stilbene, it was possible to identify activation of the Nrf2 pathway. Furthermore, the use of some experimental models presented a challenge in comparing results. In view of the above, it can be suggested that E-stilbenes have a relationship with the Nrf2 pathway, whether directly or indirectly, through different biological pathways, and in different diseases or conditions that are mainly related to inflammation and oxidative stress.

The possible role of nuclear factor erythroid-2-related factor 2 activators in the management of Covid-19

COVID-19 is caused by a novel SARS-CoV-2 leading to pulmonary and extra-pulmonary manifestations due to oxidative stress (OS) development and hyperinflammation. COVID-19 is primarily asymptomatic though it may cause acute lung injury (ALI), acute respiratory distress syndrome (ARDS), systemic inflammation, and thrombotic events in severe cases. SARS-CoV-2-induced OS triggers the activation of different signaling pathways, which counterbalances this complication. One of these pathways is nuclear factor erythroid 2-related factor 2 (Nrf2), which induces a series of cellular interactions to mitigate SARS-CoV-2-mediated viral toxicity and OS-induced cellular injury. Nrf2 pathway inhibits the expression of pro-inflammatory cytokines and the development of cytokine storm in COVID-19. Therefore, Nrf2 activators may play an essential role in reducing SARS-CoV-2 infection-induced inflammation by suppressing NLRP3 inflammasome in COVID-19. Furthermore, Nrf2 activators can attenuate endothelial dysfunction (ED), renin-angiotensin system (RAS) dysregulation, immune thrombosis, and coagulopathy. Thus this mini-review tries to clarify the possible role of the Nrf2 activators in the management of COVID-19. Nrf2 activators could be an effective therapeutic strategy in the management of Covid-19. Preclinical and clinical studies are recommended in this regard.

Ferroptosis as an emerging target in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology. Due to the rise in the incidence rate of RA and the limitations of existing therapies, the search for new treatment strategies for RA has become a global focus. Ferroptosis is a novel programmed cell death characterized by iron-dependent lipid peroxidation, with distinct differences from apoptosis, autophagy, and necrosis. Under the conditions of iron accumulation and the glutathione peroxidase 4 (GPX4) activity loss, the lethal accumulation of lipid peroxide is the direct cause of ferroptosis. Ferroptosis mediates inflammation, oxidative stress, and lipid oxidative damage processes, and also participates in the occurrence and pathological progression of inflammatory joint diseases including RA. This review provides insight into the role and mechanism of ferroptosis in RA and discusses the potential and challenges of ferroptosis as a new therapeutic strategy for RA, with an effort to provide new targets for RA prevention and treatment.

CRISPR/Cas9-Based Screening of FDA-Approved Drugs for NRF2 Activation: A Novel Approach to Discover Therapeutics for Non-Alcoholic Fatty Liver Disease

With the rising prevalence of obesity, non-alcoholic fatty liver disease (NAFLD) now affects 20-25% of the global population. NAFLD, a progressive condition associated with oxidative stress, can result in cirrhosis and liver cancer in 10% and 3% of patients suffering NAFLD, respectively. Therapeutic options are currently limited, emphasizing the need for novel treatments. In this study, we examined the potential of activating the transcription factor NRF2, a crucial player in combating oxidative stress, as an innovative approach to treating NAFLD. Utilizing a CRISPR/Cas9-engineered human HEK293T cell line, we were able to monitor the expression of heme oxygenase-1 (HMOX1), an NRF2 target, using a Nanoluc luciferase tag. Our model was validated using a known NRF2 activator, after which we screened 1200 FDA-approved drugs, unearthing six compounds (Disulfiram, Thiostrepton, Auranofin, Thimerosal, Halofantrine, and Vorinostat) that enhanced NRF2 activity and antioxidant response. These compounds demonstrated protective effects against oxidative stress induced by hydrogen peroxide and lipid droplets accumulation in vitro with hepatoma HUH-7 cells. Our study underscores the utility of CRISPR/Cas9 tagging with Nanoluc luciferase in identifying potential NRF2 activators, paving the way for potential NAFLD therapeutics.

The protective effect of resveratrol on largemouth bass (Micropterus salmoides) during out-of-season spawning

In aquaculture production, out-of-season spawning is beneficial to solve the seasonal shortage of fry that are normally produced once annually by species such as largemouth bass (Micropterus salmoides), thereby implementing year-round fry production. Maintaining low temperature over a period of several months can delay largemouth bass ovarian development, but it can cause severe stress to their reproductive function, leading to decreased fertility during out-of-season spawning. Feeding with antioxidants is one of the most effective methods to alleviate the negative effects of low temperature stress. Therefore, the purpose of this study is to: (a) evaluate the changes in oocyte morphology, antioxidant capacity, reproductive hormone-related index, cell apoptosis and autophagy during the out-of-season spawning of largemouth bass, and (b) to investigate the protective effect of the antioxidant resveratrol on this fish during out-of-season spawning from May through August. The study was divided into two groups (three replicates per group, 2000 fish per replicate): control group (Control) (exposure to water temperature of 12-17 °C) and resveratrol supplementation group (Res) (exposure to water temperature of 12-17 °C and fed with 200 mg/kg resveratrol). The results show that: (1) The serum hormones LH and E2 increased first and then remained unchanged, and the ovarian section showed that the ovary remained in stage IV. (2) In the process of off-season reproduction, a large number of follicles experienced follicular atresia, accompanied by endoplasmic reticulum expansion, nuclear chromatin condensation and mitochondrial swelling, which was relieved after feeding resveratrol. (3) Resveratrol decreased the ovarian ROS content and improved the activities of CAT and other antioxidant enzymes in the ovary and liver to some extent. (4) Resveratrol reduced the level of pro-apoptotic (Bax, Caspase3, Caspase8, Caspase9) and autophagy-related components (LC3-B, Beclin-1) while increasing the transcription level of anti-apoptotic (Bcl-2) factors. These findings suggest that resveratrol alleviates some adverse effects of largemouth bass during out-of-season spawning to some extent and provide a model for efficient and high-quality out-of-season spawning.

New Targets and Strategies for Rheumatoid Arthritis: From Signal Transduction to Epigenetic Aspect

Rheumatoid arthritis (RA) is a chronic autoimmune disease that can lead to joint damage and even permanent disability, seriously affecting patients' quality of life. At present, the complete cure for RA is not achievable, only to relieve the symptoms to reduce the pain of patients. Factors such as environment, genes, and sex can induce RA. Presently, non-steroidal anti-inflammatory drugs, DRMADs, and glucocorticoids are commonly used in treating RA. In recent years, some biological agents have also been applied in clinical practice, but most have side effects. Therefore, finding new mechanisms and targets for treating RA is necessary. This review summarizes some potential targets discovered from the perspective of epigenetics and RA mechanisms.

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.

Anti-Arthritic and Anti-Cancer Activities of Polyphenols: A Review of the Most Recent In Vitro Assays

Polyphenols have gained widespread attention as they are effective in the prevention and management of various diseases, including cancer diseases (CD) and rheumatoid arthritis (RA). They are natural organic substances present in fruits, vegetables, and spices. Polyphenols interact with various kinds of receptors and membranes. They modulate different signal cascades and interact with the enzymes responsible for CD and RA. These interactions involve cellular machinery, from cell membranes to major nuclear components, and provide information on their beneficial effects on health. These actions provide evidence for their pharmaceutical exploitation in the treatment of CD and RA. In this review, we discuss different pathways, modulated by polyphenols, which are involved in CD and RA. A search of the most recent relevant publications was carried out with the following criteria: publication date, 2012-2022; language, English; study design, in vitro; and the investigation of polyphenols present in extra virgin olive, grapes, and spices in the context of RA and CD, including, when available, the underlying molecular mechanisms. This review is valuable for clarifying the mechanisms of polyphenols targeting the pathways of senescence and leading to the development of CD and RA treatments. Herein, we focus on research reports that emphasize antioxidant properties.

Protocatechuic acid reduces H2O2-induced migration and oxidative stress of fibroblast-like synoviocytes in rheumatoid arthritis by activating Nrf2-Keap1 signaling pathway

Honeycomb (Nidus vespae) is traditional Chinese medicine and can treat rheumatoid arthritis (RA), and protocatechuic acid (PCA) is a bioactive component of honeycomb. This study aimed to investigate whether PCA could reduce the H₂O₂-induced migration and oxidative stress of RA fibroblast-like synoviocytes (RA-FLSs). H₂O₂-induced RA-FLSs were used to simulate the in vitro model of RA. The viability, apoptosis, migration, invasion, and oxidative stress of RA-FLSs were detected by Cell Counting Kit-8 (CCK-8), terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, wound healing, transwell assays, DCFDA staining, and malonaldehyde and superoxide dismutase enzyme-linked immunosorbent assay kits. The expression of migration and invasion-related proteins and Nrf2/Keap1 signaling pathway-related proteins was analyzed by western blotting. As a result, PCA suppressed the viability, migration, invasion, and oxidative and promoted apoptosis of H₂O₂-induced RA-FLSs by activating the Nrf2/Keap1 signaling pathway. ML-385, an Nrf2 inhibitor, could enhance the viability, migration, invasion, and oxidative and inhibited apoptosis of H₂O₂-induced RA-FLSs. In conclusion, PCA reduced H₂O₂-induced migration and oxidative stress of RA-FLSs by activating the Nrf2-Keap1 signaling pathway.

Activation of the Nrf2 Antioxidant Pathway by Longjing Green Tea Polyphenols in Mice Livers

Previous studies have revealed that green tea polyphenol (GTP) could protect against liver injury due to oxidative stress. However, the mechanism underlying the bioactive actions of GTP in the liver has not been systematically evaluated. This study aimed to investigate the effect of GTP on the activation of the nuclear factor erythroid-2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (keap1) pathway, using in silico and in vivo methods. Furthermore, the regulation of Nrf2 downstream target antioxidant response element (ARE) was also evaluated. The high-performance liquid chromatography analysis indicated that GTP includes 9 major compounds, and molecule docking analysis demonstrated that most of these polyphenols have a strong binding affinity with the keap1 Kelch domain, where keap1 binds to the Neh2 domain of Nrf2. Remarkably, the predominant compound of GTP, that is, epigallocatechin gallate, displayed the best binding affinity score, which can fully occupy all 3 polar subpockets of the keap1 Kelch domain. The Nrf2, keap1, and Nrf2 downstream target gene expression levels were changed in the livers compared to the control group. It showed that the Nrf2 expression level was significantly upregulated in GTP-induced mice liver across most treatments, while the keap1 expression level remained unchanged. Subsequently, we observed a significant increasing trend in the expression of the downstream ARE, including antioxidative enzymes, liver phase II enzymes, and liver efflux transporters in mice livers. The present study demonstrated that GTP could activate the Nrf2 signaling pathway by interrupting the Nrf2-keap1 protein–protein interaction

Ageing and Osteoarthritis Synergically Affect Human Synoviocyte Cells: An In Vitro Study on Sex Differences

Osteoarthritis is a chronic inflammatory disease that affects all of the joints, especially those of the elderly. Aging is a natural and irreversible biological process implicated in the pathophysiology of many chronic diseases, such as osteoarthritis. Inflammation and oxidative stress are the main factors involved in osteoarthritis and aging, respectively, with the production of several pro-inflammatory cytokines such as Interleukin 1β (IL1β) and reactive oxygen species. The aim of the study was to set-up an in vitro model of osteoarthritis and aging, focusing on the sex differences by culturing male and female fibroblast-like synoviocytes (FLSs) with IL1β, hydrogen peroxide (H₂O₂), IL1β+H₂O₂ or a growth medium (control). IL1β+H₂O₂ reduced the cell viability and microwound healing potential, increased Caspase-3 expression and reactive oxygen species and IL6 production; IL1β increased IL6 production more than the other conditions did; H₂O₂ increased Caspase-3 expression and reactive oxygen species production; Klotho expression showed no differences among the treatments. The FLSs from female donors demonstrated a better response capacity in unfavorable conditions of inflammation and oxidative stress than those from the male donors did. This study developed culture conditions to mimic the aging and osteoarthritis microenvironment to evaluate the behavior of the FLSs which play a fundamental role in joint homeostasis, focusing on the sex-related aspects that are relevant in the osteoarthritis pathophysiology.

Triacetyl Resveratrol Inhibits PEDV by Inducing the Early Apoptosis In Vitro

PEDV represents an ancient Coronavirus still causing huge economic losses to the porcine breeding industry. Resveratrol has excellent antiviral effects. Triacetyl resveratrol (TCRV), a novel natural derivative of resveratrol, has been recently discovered, and its pharmacological effects need to be explored further. This paper aims to explore the relationship between PEDV and TCRV, which offers a novel strategy in the research of antivirals. In our study, Vero cells and IPEC-J2 cells were used as an in vitro model. First, we proved that TCRV had an obvious anti-PEDV effect and a strong inhibitory effect at different time points. Then, we explored the mechanism of inhibition of PEDV infection by TCRV. Our results showed that TCRV could induce the early apoptosis of PEDV-infected cells, in contrast to PEDV-induced apoptosis. Moreover, we observed that TCRV could promote the expression and activation of apoptosis-related proteins and release mitochondrial cytochrome C into cytoplasm. Based on these results, we hypothesized that TCRV induced the early apoptosis of PEDV-infected cells and inhibited PEDV infection by activating the mitochondria-related caspase pathway. Furthermore, we used the inhibitors Z-DEVD-FMK and Pifithrin-α (PFT-α) to support our hypothesis. In conclusion, the TCRV-activated caspase pathway triggered early apoptosis of PEDV-infected cells, thereby inhibiting PEDV infections.

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 resveratrol on rheumatoid arthritis: From bench to bedside

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by symmetrical polyarthritis as its main clinical manifestation. Uncontrolled RA eventually leads to joint deformities and loss of function. Currently, the pathogenesis of RA remains under discussion, and RA treatment is still at the bottleneck stage. Resveratrol has long been regarded as a potential antioxidant drug for RA treatment. Currently, resveratrol is considered to exert therapeutic effects on RA by activating silent information regulator 1 (SIRT1) and its downstream pathways. There is notable crosstalk between the SIRT1 and NF-κB pathways, and these pathways, which play an essential role in the development of RA, are unexpectedly linked to the influence of resveratrol. Based on recent studies of almost all the pathways that resveratrol can affect, this review summarizes a regulatory chain of core components that cover multiple tracks. We also list the effects of resveratrol on immune cells and other subtle controls, which can help clinicians understand the known mechanism of resveratrol and better treat patients with RA.

Insights into the Anti-inflammatory and Antiviral Mechanisms of Resveratrol

Resveratrol is a naturally occurring stilbene phytoalexin phenolic compound, which has been extensively studied on its biological activity. It has been widely accepted that resveratrol possesses anti-inflammatory and antiviral activities. In this review, we summarize the anti-inflammatory dosages and mechanism and antiviral mechanism of resveratrol. Since viral infections are often accompanied by inflammation, we propose that the NF-κB signaling pathway is a key and common molecular mechanism of resveratrol to exert anti-inflammatory and antiviral effects. For future studies, we believe that resveratrol's anti-inflammatory and antiviral mechanisms can consider the upstream signaling molecules of the NF-κB signaling pathway. For resveratrol antivirus, future studies can be conducted on the interaction of resveratrol with key proteins or important enzymes of the virus. In addition, we also think that the clinical application of resveratrol is very important. In short, resveratrol is a promising anti-inflammatory and antiviral drug, and research on it needs to be expanded.

Ferroptosis in inflammatory arthritis: A promising future

Ferroptosis is a kind of regulatory cell death (RCD) caused by iron accumulation and lipid peroxidation, which is characterized by mitochondrial morphological changes and has a complex regulatory network. Ferroptosis has been gradually emphasized in the pathogenesis of inflammatory arthritis. In this review, we summarized the relevant research on ferroptosis in various inflammatory arthritis including rheumatoid arthritis (RA), osteoarthritis, gout arthritis, and ankylosing spondylitis, and focused on the relationship between RA and ferroptosis. In patients with RA and animal models of RA, there was evidence of iron overload and lipid peroxidation, as well as mitochondrial dysfunction that may be associated with ferroptosis. Ferroptosis inducers have shown good application prospects in tumor therapy, and some anti-rheumatic drugs such as methotrexate and sulfasalazine have been shown to have ferroptosis modulating effects. These phenomena suggest that the role of ferroptosis in the pathogenesis of inflammatory arthritis will be worth further study. The development of therapeutic strategies targeting ferroptosis for patients with inflammatory arthritis may be a promising future.

Grape seed proanthocyanidin extract induces apoptotic and autophagic cell death in rheumatoid arthritis fibroblast-like synoviocytes

Objectives

In this study, we aimed to evaluate the association between grape seed proanthocyanidin extract (GSPE) and rheumatoid arthritis-fibroblast-like synoviocytes (RA-FLSs) and to investigate whether GSPE induces cell death in RA-FLSs.

Materials and methods

The FLSs were isolated from RA synovial tissues. Cell viability and cell cycle staging were analyzed using a hemocytometer and flow cytometry. Caspase 3 and poly (ADP-ribose) polymerase (PARP) proteins were analyzed using Western blotting with z-VAD-fmk. Protein LC3 and polyubiquitin-binding protein p62 that were degraded by autophagy were evaluated using Western blotting with 3-methyladenine and chloroquine. Reactive oxygen species (ROS) were also evaluated.

Results

When RA-FLSs were treated with GSPE, cell viability decreased, the number of cells in sub-G1 and G2/M phases increased, and the expression of pro-PARP and pro-caspase 3 proteins decreased in a concentration-dependent manner. This result was offset, when the cells were co-treated with the pan-caspase inhibitor z-VAD-fmk. The reduced cell viability, increased expression of LC3-II protein, and reduced expression of p62 protein with GSPE treatment were offset, when RA-FLSs were co-treated with GSPE and autophagy inhibitors 3-methyladenine and chloroquine. The level of ROS in RA-FLSs treated with GSPE was significantly lower than treatment with N-acetyl-cysteine, a ROS inhibitor.

Conclusion

Our study results show that GSPE induces apoptotic and autophagic cell death and inhibites reactive oxygen species in RA-FLSs.

Resveratrol Alleviating the Ovarian Function Under Oxidative Stress by Alternating Microbiota Related Tryptophan-Kynurenine Pathway

Oxidative stress (OS) is a key factor regulating the systemic pathophysiological effects and one of the fundamental mechanisms associated with aging and fertility deterioration. Previous studies revealed that resveratrol (RV) exhibits a preventive effect against oxidative stress in the ovary. However, it remains unknown whether gut microbiota respond to resveratrol during an OS challenge. In Exp. 1, layers received intraperitoneal injection of tert-butyl hydroperoxide (tBHP) (0 or 800 μmol/kg BW) or received resveratrol diets (0 or 600 mg/kg) for 28 days. In Exp. 2, the role of intestinal microbiota on the effects of resveratrol on tBHP-induced oxidative stress was assessed through fecal microbiota transplantation (FMT). The OS challenge reduced the egg-laying rate and exhibited lower pre-hierarchical follicles and higher atretic follicles. Oral RV supplementation ameliorated the egg-laying rate reduction and gut microbiota dysbiosis. RV also reversed the tryptphan-kynurenine pathway, upregulated nuclear factor E2-related factor 2 (Nrf2) and silent information regulator 1(SIRT1) levels, and decreased the expression of forkhead box O1 (FoxO1) and P53. These findings indicated that the intestinal microbiota-related tryptophan-kynurenine pathway is involved in the resveratrol-induced amelioration of ovary oxidative stress induced by tBHP in the layer model, while SIRT1-P53/FoxO1 and Nrf2-ARE signaling pathway were involved in this process.

An update of Nrf2 activators and inhibitors in cancer prevention/promotion

NF-E2-related factor 2 (Nrf2) protein is a basic-region leucine zipper transcription factor that defends against endogenous or exogenous stressors. By inducing several cytoprotective and detoxifying gene expressions, Nrf2 can increase the sensitivity of the cells to oxidants and electrophiles. Transient Nrf2 activation, by its specific activators, has protective roles against carcinogenesis and cancer development. However, permanent activation of Nrf2 promotes various cancer properties, comprising malignant progression, chemo/radio resistance, and poor patient prognosis. Taken together, these findings suggest that reaching an optimal balance between paradoxical functions of Nrf2 in malignancy may render a selective improvement to identify therapeutic strategies in cancer treatment. In this review, we describe lately discovered Nrf2 inducers and inhibitors, and their chemopreventive and/or anticancer activities.

The Nrf2 pathway signifies one of the most significant cell defense procedures against exogenous or endogenous stressors. Certainly, by increasing the expression of several cytoprotective genes, the transcription factor Nrf2 can shelter cells and tissues from multiple sources of damage including electrophilic, xenobiotic, metabolic, and oxidative stress. Notably, the aberrant activation or accumulation of Nrf2, a common event in many tumors, confers a selective advantage to cancer cells and is connected to malignant progression, therapy resistance, and poor prognosis. Therefore, lately, Nrf2 has arisen as a hopeful target in treatment of cancer, and many struggles have been made to detect therapeutic strategies intended at disrupting its pro-oncogenic role. By summarizing the outcomes from past and recent studies, this review provided an overview concerning the Nrf2 pathway and the molecular mechanisms causing Nrf2 hyperactivation in cancer cells. Finally, this paper also described some of the most promising therapeutic approaches that have been successfully employed to counteract Nrf2 activity in tumors, with a particular emphasis on the development of natural compounds and the adoption of drug repurposing strategies.

A comprehensive insight into effects of resveratrol on molecular mechanism in rheumatoid arthritis: A literature systematic review

AIM

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease, which is characterized by massive pain and destruction of synovial joints, leads to bone erosion, damage to cartilage, and disability. Several studies suggested that resveratrol supplementation may be effective in the prevention and management of RA. Therefore, a systematic review was conducted to summarize published studies that assess the effect of resveratrol supplementation on the complications of RA.

METHODS

A comprehensive search to identify in vitro, animal, and human studies investigating the impact of resveratrol on the complications of RA was performed up to February 2022. Two independent reviewers evaluated studies based on inclusion/exclusion criteria and performed data extraction.

RESULTS

All studies examining the effects of resveratrol supplementation on the complications of RA were included. From a total of 571 retrieved articles, 32 studies were eligible for the current systematic review. The evidence reviewed here indicates that resveratrol supplementation may exert beneficial effects on the complications of RA by attenuating inflammation and oxidative stress, modulating the immune response, and down-regulating the messenger RNA expression of genes related to inflammatory pathways.

CONCLUSION

Due to the promising therapeutic effects of resveratrol on RA complications and limited number of human studies in this subject, further clinical trials are suggested.

Applications of resveratrol in the treatment of gastrointestinal cancer

Natural product compounds have lately attracted interest in the scientific community as a possible treatment for gastrointestinal (GI) cancer, due to their anti-inflammatory and anticancer properties. There are many preclinical, clinical, and epidemiological studies, suggesting that the consumption of polyphenol compounds, which are abundant in vegetables, grains, fruits, and pulses, may help to prevent various illnesses and disorders from developing, including several GI cancers. The development of GI malignancies follows a well-known path, in which normal gastrointestinal cells acquire abnormalities in their genetic composition, causing the cells to continuously proliferate, and metastasize to other sites, especially the brain and liver. Natural compounds with the ability to affect oncogenic pathways might be possible treatments for GI malignancies, and could easily be tested in clinical trials. Resveratrol is a non-flavonoid polyphenol and a natural stilbene, acting as a phytoestrogen with anti-cancer, cardioprotective, anti-oxidant, and anti-inflammatory properties. Resveratrol has been shown to overcome resistance mechanisms in cancer cells, and when combined with conventional anticancer drugs, could sensitize cancer cells to chemotherapy. Several new resveratrol analogs and nanostructured delivery vehicles with improved anti-GI cancer efficacy, absorption, and pharmacokinetic profiles have already been developed. This present review focuses on the in vitro and in vivo effects of resveratrol on GI cancers, as well as the underlying molecular mechanisms of action.

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.

Resveratrol mitigates diclofenac-induced hepatorenal toxicity in rats via modulation of miR-144/Nrf2/GSH axis

Despite the extensive therapeutic uses of diclofenac, it may cause several adverse effects, including hepatorenal injury. The antioxidant and anti-inflammatory properties of resveratrol, a polyphenolic compound, make the agent effective in ameliorating a variety of drug-induced injuries. This study investigated the potential beneficial effects of resveratrol on diclofenac-induced hepatorenal toxicity and explored the role of miR-144 and its relationship to oxidative stress and inflammation triggered by diclofenac. Rats were divided into four groups: control; diclofenac group received diclofenac (10 mg/kg/day, intraperitoneal [ip]) for 7 days; prevention group received resveratrol concomitantly with diclofenac for 7 days; and the treatment group received diclofenac for 7 days followed by resveratrol (20 mg/kg/day, per oral) for another 7 days. Diclofenac administration induced a significant increase in serum hepatorenal biomarkers and histopathological aberrations. In addition, diclofenac upregulated miR-144 while reducing nuclear factor erythroid 2-related factor 2 (Nrf2) protein levels and glutathione (GSH) content. Moreover, diclofenac induced tissue inflammation and apoptosis as evidenced by increased protein expression of nuclear factor kappa B (NF-κB), tumor necrosis factor α (TNF-α), and caspase-3. Intriguingly, resveratrol prevention or treatment significantly mitigated the toxic effects of diclofenac as manifested by normalization of the hepatorenal functions and amelioration of the histopathological changes. Resveratrol also triggered miR-144 downregulation with Nrf2 upregulation. Consequently, resveratrol showed hepatorenal antioxidant, anti-inflammatory, and antiapoptotic activities as manifested by improvement in the antioxidant markers along with a decline in NF-κB, TNF-α, and caspase-3 expressions. In conclusion, this study demonstrates a potential therapeutic role of resveratrol in mitigating diclofenac-induced hepatorenal insult, possibly via modulating miR-144/Nrf2/GSH axis.

Adipose-Derived Mesenchymal Stem Cells Combined With Extracellular Vesicles May Improve Amyotrophic Lateral Sclerosis

The complexity of central nervous system diseases together with their intricate pathogenesis complicate the establishment of effective treatment strategies. Presently, the superiority of adipose-derived mesenchymal stem cells (ADSCs) on neuronal injuries has attracted significant attention. Similarly, extracellular vesicles (EVs) are potential interventional agents that could identify and treat nerve injuries. Herein, we reviewed the potential effects of ADSCs and EVs on amyotrophic lateral sclerosis (ALS) injured nerves, and expound on their practical application in the clinic setting. This article predominantly focused on the therapeutic role of ADSCs concerning the pathogenesis of ALS, the protective and reparative effects of EVs on nerve injury, as well as the impact following the combined usage of ADSCs and EVs in ALS.

Dietary polyphenols for management of rheumatoid arthritis: Pharmacotherapy and novel delivery systems

Rheumatoid arthritis (RA) is a chronic, complex, systemic autoimmune disease causing chronic inflammation, swelling, and pain. It affects pulmonary and ocular physiology, gastrointestinal disturbance, skeletal disorders, and renal malfunctioning. Although conventional and biological drugs available to treat RA are potent and effective, they lead to life-threatening side effects and patient discomfort. Hence, alternative therapies are explored for their treatment which is safe, effective, and economical. Herbal drugs are widely used as an alternative therapy and some medicinal plants, especially dietary polyphenols proved their efficacy in treating RA. Polyphenols are secondary metabolites of plants possessing several pharmacological actions. They exert anti-inflammatory, immunomodulatory and anti-rheumatoid activity by modulating tumor necrosis factor, mitogen-activated protein kinase, nuclear factor kappa-light-chain-enhancer of activated B cells, and c-Jun N-terminal kinases. Thus, polyphenols could be a promising option for the management of RA. Unfortunately, polyphenols suffer from poor bioavailability due to their physicochemical properties and incorporation into novel delivery systems such as liposomes, nanoparticles, nanoemulsions, micelles improved their oral bioavailability. This review article summarizes dietary polyphenols, their pharmacological actions and novel delivery systems for the treatment of RA. Nevertheless, the commercial translation of polyphenols could be only possible after establishing their safety profile and successful clinical trials.

Recent Advances in Understanding Nrf2 Agonism and Its Potential Clinical Application to Metabolic and Inflammatory Diseases

Oxidative stress is a major component of cell damage and cell fat, and as such, it occupies a central position in the pathogenesis of metabolic disease. Nuclear factor-erythroid-derived 2-related factor 2 (Nrf2), a key transcription factor that coordinates expression of genes encoding antioxidant and detoxifying enzymes, is regulated primarily by Kelch-like ECH-associated protein 1 (Keap1). However, involvement of the Keap1–Nrf2 pathway in tissue and organism homeostasis goes far beyond protection from cellular stress. In this review, we focus on evidence for Nrf2 pathway dysfunction during development of several metabolic/inflammatory disorders, including diabetes and diabetic complications, obesity, inflammatory bowel disease, and autoimmune diseases. We also review the beneficial role of current molecular Nrf2 agonists and summarize their use in ongoing clinical trials. We conclude that Nrf2 is a promising target for regulation of numerous diseases associated with oxidative stress and inflammation. However, more studies are needed to explore the role of Nrf2 in the pathogenesis of metabolic/inflammatory diseases and to review safety implications before therapeutic use in clinical practice.

Ferroptosis in Rheumatoid Arthritis: A Potential Therapeutic Strategy

Ferroptosis is one of the newly discovered forms of cell-regulated death characterized by iron-dependent lipid peroxidation. Extensive research has focused on the roles of ferroptosis in tumors, blood diseases, and neurological diseases. Some recent findings have indicated that ferroptosis may also be related to the occurrence and development of inflammatory arthritis. Ferroptosis may be a potential therapeutic target, and few studies in vitro and animal models have shown implications in the pathogenesis of inflammatory arthritis. This mini review discussed the common features between ferroptosis and the pathogenesis of rheumatoid arthritis (RA), and evaluated therapeutic applications of ferroptosis regulators in preclinical and clinical research. Some critical issues worth paying attention to were also raised to guide future research efforts.

Antioxidant Effects and Potential Molecular Mechanism of Action of Limonium aureum Extract Based on Systematic Network Pharmacology

Oxidative stress is the redox imbalance state of organisms that involves in a variety of biological processes of diseases. Limonium aureum (L.) Hill. is an excellent wild plant resource in northern China, which has potential application value for treating oxidative stress. However, there are few studies that focused on the antioxidant effect and related mechanism of L. aureum. Thus, the present study combining systematic network pharmacology and molecular biology aimed to investigate the antioxidant effects of L. aureum and explore its underlying anti-oxidation mechanisms. First, the antioxidant activity of L. aureum extracts was confirmed by in vitro and intracellular antioxidant assays. Then, a total of 11 bioactive compounds, 102 predicted targets, and 70 antioxidant-related targets were obtained from open source databases. For elucidating the molecular mechanisms of L. aureum, the PPI network and integrated visualization network based on bioinformatics assays were constructed to preliminarily understand the active compounds and related targets. The subsequent enrichment analysis results showed that L. aureum mainly affect the biological processes involving oxidation-reduction process, response to drug, etc., and the interference with these biological processes might be due to the simultaneous influence on multiple signaling pathways, including the HIF-1 and ERBB signaling pathways. Moreover, the mRNA levels of predicted hub genes were measured by qRT-PCR to verify the regulatory effect of L. aureum on them. Collectively, this finding lays a foundation for further elucidating the anti-oxidative damage mechanism of L. aureum and promotes the development of therapeutic drugs for oxidative stress.

Andrographolide emeliorates maltol aluminium-induced neurotoxicity via regulating p62-mediated Keap1-Nrf2 pathways in PC12 cells

CONTEXT

Andrographolide (Andro) has a neuroprotective effect and a potential for treating Alzheimer's disease (AD), but the mechanism has not been elucidated.

OBJECTIVE

The efficacy of Andro on p62-mediated Kelch-like ECH-associated protein 1(Keap1)-Nuclear factor E2 related factor 2 (Nrf2) pathways in the aluminium maltolate (Al(mal)₃)-induced neurotoxicity in PC12 cell was explored.

MATERIALS AND METHODS

PC12 cells were induced by Al(mal)₃ (700 μM) to establish a neurotoxicity model. Following Andro (1.25, 2.5, 5, 10, 20, 40 μM) co-treatment with Al(Mal)₃, cell viability was detected with MTT, protein expression levels of β-amyloid precursor protein (APP), β-site APP cleaving enzyme 1 (BACE1), Tau, Nrf2, Keap1, p62 and LC3 were measured via western blotting or immunofluorescence analyses. Nrf2, Keap1, p62 and LC3 mRNA, were detected by reverse transcription-quantitative PCR.

RESULTS

Compared with the 700 μM Al(mal)₃ group, Andro (5, 10 μM) significantly increased Al(mal)3-induced cell viability from 67.4% to 91.9% and 91.2%, respectively, and decreased the expression of APP, BACE1 and Keap1 proteins and the ratio of P-Tau to Tau (from 2.75- fold to 1.94- and 1.70-fold, 2.12-fold to 1.77- and 1.56-fold, 0.68-fold to 0.51- and 0.55-fold, 1.45-fold to 0.82- and 0.91-fold, respectively), increased the protein expression of Nrf2, p62 and the ratio of LC3-II/LC3-I (from 0.67-fold to 0.93- and 0.94-fold, 0.64-fold to 0.88- and 0.87-fold, 0.51-fold to 0.63- and 0.79-fold, respectively), as well as the mRNA expression of Nrf2, p62 and LC3 (from 0.48-fold to 0.92-fold, 0.49-fold to 0.92-fold, 0.25-fold to 0.38-fold). Furthermore, Nrf2 and p62 nuclear translocation were increased and keap1 in the cytoplasm was decreased in the presence of Andro. Silencing p62 or Nrf2 can significantly reduce the protein and mRNA expression of Nrf2 and p62 under co-treatment with Andro and Al(mal)₃.

DISCUSSION AND CONCLUSIONS

Our results suggested that Andro could be a promising therapeutic lead against Al-induced neurotoxicity by regulating p62-mediated keap1-Nrf2 pathways.

Resveratrol mediates its anti-cancer effects by Nrf2 signaling pathway activation

Aim and background

Cancer represents a major health problem with an exceedingly high toll on the patients, their families, and the economy. Cancers are also associated with high mortality rates. Existing therapies for cancer are generally ineffective with many side effects.

Method

A search was conducted on Pubmed, Google Scholar, Scopus, and web of science databases, and articles related to anticancer effects of resveratrol were collected.

Results

Resveratrol is a natural compound that can activate the Nrf2 transcription factor. Nfr2 translocates to the nucleus and induces antioxidant gene expression. In different cell lines, resveratrol can increase apoptosis and inhibit the proliferation of cancer cells.

Conclusion

We found that resveratrol shows efficacy for the treatment of cancer, but due to high controversy on the Nrf2 signaling pathway and mechanisms of resveratrol action, additional studies should be conducted to better characterize its mode-of-action in cancer.

Graphical Abstract

Traditional herbal medicine: Therapeutic potential in rheumatoid arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease influenced by diverse endogenous and exogenous factors. It is characterized by cartilage and bone destruction. The current conventional allopathic therapy is expensive and carries adverse side effects. Recently, there were some ethnopharmacological studies on RA including anti-RA effects and therapeutic targets of distinct dosage forms of traditional herbal medicines (THMs).

AIM OF THE REVIEW

This review provides a brief overview of the current understanding of the potential pharmacological mechanisms of THMs (active constituents, extracts and prescriptions) in RA. This study is intended to provide comprehensive information and reference for exploring new therapeutic strategies of THMs in the RA treatment.

MATERIALS AND METHODS

This review captured scientific literatures invivo and vitro experiments on effects of anti-RA THMs published between 2016 and 2021 from journals and electronic databases (e.g. PubMed, Elsevier, Science Direct, Web of Science and Google Scholar). Relevant literatures were searched and analyzed by using keywords such as 'rheumatoid arthritis AND traditional herbal medicines', 'rheumatoid arthritis AND immune cells', 'rheumatoid arthritis AND inflammation', 'rheumatoid arthritis AND miRNA', 'rheumatoid arthritis AND Angiogenesis', 'rheumatoid arthritis AND oxidative stress', 'rheumatoid arthritis AND osteoclasts', 'rheumatoid arthritis AND CIA model', 'rheumatoid arthritis AND AA model' AND 'rheumatoid arthritis herbal prescription'.

RESULTS

Experiments in vitro and in vivo jointly demonstrated the potential of THMs in the RA treatment. There are plentiful therapeutic targets in RA. THMs and active ingredients could alleviate RA symptoms through different therapeutic targets, such as immunoregulation, inflammation, fibroblast-like synoviocytes (FLSs), microRNAs (miRNAs), angiogenesis, oxidative stress, osteoclasts and multiple targets interaction. Anti-RA THMs, active ingredients and prescriptions through corresponding therapeutic targets were summarized and classified.

CONCLUSIONS

Flavonoids, phenolic acids, alkaloids and triterpenes of THMs are identified as the main components to ameliorate RA. Regulation of different and multiple related therapeutic targets by THMs and their active ingredients were associated with greater therapeutic benefits, among which inflammation is the main therapeutic target. Nonetheless, further studies are required to unravel the complexities and in-depth mechanisms of THMs in alleviating RA.

Resveratrol ameliorates thoracic blast exposure-induced inflammation, endoplasmic reticulum stress and apoptosis in the brain through the Nrf2/Keap1 and NF-κB signaling pathway

Blast injuries include the various types of internal and external trauma caused by the impact force of high-speed blast waves with multiple mechanisms involved. Thoracic blast exposure could induce neurotrauma as well, but effective therapies are lacking. Resveratrol is a polyphenol flavonoid secreted by plants and has been shown to provide cardiovascular protection and play anti-inflammatory, anti-oxidation and anti-cancer roles. However, the effects of resveratrol on thoracic blast exposure-induced brain injury have not been investigated. To explore this, a mouse model of thoracic blast exposure-induced brain injury was established. Sixty C57BL/6 wild type mice were randomly divided equally into four groups (one control group, one model group, and model groups with 25 or 50 mg/kg resveratrol injected intraperitoneally). As traumatic brain injury often accompanied by mental symptoms, cognitive dysfunction and anxious behavior were evaluated by Y maze, elevated plus maze and open field test. We also examined the mice for histopathological changes by hematoxylin-eosin staining; the expressions of inflammatory-related factors by ELISA; endoplasmic reticulum stress in brain tissue via the generation of reactive oxygen species (ROS) and the expressions of inositol-requiring enzyme-α (IRE-α) and C/EBP homologous protein (CHOP); apoptosis by measuring levels of Bax, p53 and Bcl-2. In addition, proteins of related pathways were also studied by western blotting. We found that resveratrol significantly reduced the levels of inflammatory-related factors, including interleukin (IL)-1β, IL-4, and high mobility group box protein 1(HMGB1), and increased the level of anti-inflammatory-related factor, IL-10, under thoracic blast exposure (P < 0.05). Cognitive dysfunction and anxious behavior were also ameliorated by resveratrol. In brain tissue, resveratrol significantly attenuated thoracic blast exposure-induced generation of ROS and expressions of IRE-α and CHOP, lowered the expressions of Bax and p53, and maintained Bcl-2 expression (P < 0.05). Additionally, resveratrol significantly ameliorated thoracic blast exposure-induced increases of Kelch-like ECH-associated protein 1 (Keap1) and nuclear factor (NF)-κB and the decrease in nuclear factor erythroid 2-related factor 2(Nrf2) expression in the brain (P < 0.05). Our results indicate that resveratrol has a protective effect on thoracic blast exposure-induced brain injury that is likely mediated through the Nrf2/Keap1 and NF-κB signaling pathways.

Resveratrol as an Adjunctive Therapy for Excessive Oxidative Stress in Aging COVID-19 Patients

The coronavirus disease 2019 (COVID-19) pandemic continues to burden healthcare systems worldwide. COVID-19 symptoms are highly heterogeneous, and the patient may be asymptomatic or may present with mild to severe or fatal symptoms. Factors, such as age, sex, and comorbidities, are key determinants of illness severity and progression. Aging is accompanied by multiple deficiencies in interferon production by dendritic cells or macrophages in response to viral infections, resulting in dysregulation of inflammatory immune responses and excess oxidative stress. Age-related dysregulation of immune function may cause a more obvious pathophysiological response to SARS-CoV-2 infection in elderly patients and may accelerate the risk of biological aging, even after recovery. For more favorable treatment outcomes, inhibiting viral replication and dampening inflammatory and oxidative responses before induction of an overt cytokine storm is crucial. Resveratrol is a potent antioxidant with antiviral activity. Herein, we describe the reasons for impaired interferon production, owing to aging, and the impact of aging on innate and adaptive immune responses to infection, which leads to inflammation distress and immunosuppression, thereby causing fulminant disease. Additionally, the molecular mechanism by which resveratrol could reverse a state of excessive basal inflammatory and oxidative stress and low antiviral immunity is discussed.

Role of oxidative stress in pathophysiology of rheumatoid arthritis: insights into NRF2-KEAP1 signalling

Rheumatoid arthritis is one of the most prevalent, chronic, inflammatory disorders involving multiple articular and extra-articular complications. Immune deregulation owing to a combinatorial network of cells, inflammatory components, degrading enzymes, angiogenetic factors, exhibiting pleiotropy, synergy, or redundancy, is a critical hallmark for synovial inflammatory milieu reasoning clinical heterogeneity and variability of the disease. As a prototype of autoimmune disease, the pathophysiology of rheumatoid arthritis has been linked to oxidative stress. However, the exact mechanism for these potential driving factors contributing to disease inception and perpetuation is yet elusive. Nuclear factor erythroid 2-related factor 2 - Kelch ECH associating protein 1 (Nrf2-Keap1) pathway, controlled via multifactorial regulation, functions as a ubiquitous, evolutionarily conserved intracellular defense mechanism. Nrf2-Keap1 signalling maintains homeostatic responses against a plethora of environmental or endogenous deviations in cellular growth, death, redox metabolism, inflammation, bone remodelling, detoxification, etc. Administration of antioxidants as an add-on pharmacotherapy along with conventional drugs has been elucidated as a better measure for disease management. Some of the most promising natural and synthetic redox-based therapeutic compounds function as either scavengers of reactive species, or inhibitors of their sources, or activators of an endogenous antioxidant system (Nrf2-Keap1). The present review focuses on the binomial "rheumatoid arthritis-oxidative stress", bringing insights into their pathophysiological interrelationships and Nrf2 signalling, as well as the implications of potential diagnostic oxidative stress biomarkers and therapeutic interventions directed for disease management in patients with rheumatoid arthritis.Highlights:RA has complex etiopathogenesis, evolving from multiple endogenous and exogenous factors with oxidative stress as a critical pathogenic signature.Oxidative damage and damaged compounds could serve as potent biomarkers for disease diagnosis, therapeutic response, and prognosis.One of the supreme cytoprotective signalling cascades, the Nrf2-Keap1 pathway has been known to elicit a protective effect against RA and various other autoimmune, inflammatory, degenerative disorders.Inclusion of natural and synthetic antioxidants has been encouraged by various studies for additional therapy to conventional drugs for better management of the disease.

MicroRNAs Involved in Oxidative Stress Processes Regulating Physiological and Pathological Responses

Oxidative stress influences several physiological and pathological cellular events, including cell differentiation, excessive growth, proliferation, apoptosis, and the inflammatory response. Therefore, oxidative stress is involved in the pathogenesis of various diseases, including pulmonary fibrosis, epilepsy, hypertension, atherosclerosis, Parkinson's disease, cardiovascular disease, and Alzheimer's disease. Recent studies have shown that several microRNAs (miRNAs) are involved in developing various diseases caused by oxidative stress and that miRNAs may be helpful to determine the inflammatory characteristics of immune responses during infection and disease. This review describes the known effects of miRNAs on reactive oxygen species to induce oxidative stress and the miRNA regulatory mechanisms involved in the uncoupling of Keap1-Nrf2 complexes. Finally, we summarized the functions of miRNAs in several antioxidant genes. Understanding the crosstalk between miRNAs and oxidative stress-inducing factors during physiological and pathological cellular events may have implications for designing more effective treatments for immune diseases.

Resveratrol and endoplasmic reticulum stress: A review of the potential protective mechanisms of the polyphenol

The endoplasmic reticulum (ER) is an organelle that performs a set of essential functions in cellular biology. These include synthesis of lipids, homeostasis of calcium, and controlling the folding of proteins. Inflammation and oxidative stress are two important reasons behind the accumulation of misfolded or unfolded proteins in the ER. In such circumstances, a series of measures are undertaken in the cell which are collectively called unfolded protein response (UPR). The aim of UPR is to reduce the burden of protein aggregates and promote survival. However, extended and unrestricted ER stress (ERS) can induce further inflammation and apoptosis. ERS and the UPR are involved in different diseases such as neurodegenerative and cardiovascular diseases. Resveratrol (RSV), a natural polyphenol, has well-documented evidence supporting its numerous biological properties including antioxidant, antiinflammatory, antiobesity, antidiabetic, and antiischemic activities. The compound is also known for its potential beneficial effects on cognitive function and liver, kidney, and lung health. In this review, the role of ERS in several pathological conditions and the potential protective effects of RSV are discussed. However, the scarcity of clinical data means that more research needs to be conducted to gain a lucid understanding of RSV's effects on endoplasmic reticulum stress (ERS) in humans.

Intestinal protection by proanthocyanidins involves anti-oxidative and anti-inflammatory actions in association with an improvement of insulin sensitivity, lipid and glucose homeostasis

Recent advances have added another dimension to the complexity of cardiometabolic disorders (CMD) by directly implicating the gastrointestinal tract as a key player. In fact, multiple factors could interfere with intestinal homeostasis and elicit extra-intestinal CMD. As oxidative stress (OxS), inflammation, insulin resistance and lipid abnormalities are among the most disruptive events, the aim of the present study is to explore whether proanthocyanidins (PACs) exert protective effects against these disorders. To this end, fully differentiated intestinal Caco-2/15 cells were pre-incubated with PACs with and without the pro-oxidant and pro-inflammatory iron/ascorbate (Fe/Asc). PACs significantly reduce malondialdehyde, a biomarker of lipid peroxidation, and raise antioxidant SOD2 and GPx via the increase of NRF2/Keap1 ratio. Likewise, PACs decrease the inflammatory agents TNFα and COX2 through abrogation of NF-κB. Moreover, according to crucial biomarkers, PACs result in lipid homeostasis improvement as reflected by enhanced fatty acid β-oxidation, diminished lipogenesis, and lowered gluconeogenesis as a result of PPARα, γ and SREBP1c modulation. Since these metabolic routes are mainly regulated by insulin sensitivity, we have examined the insulin signaling pathway and found an upregulation of phosphoPI3K/Akt and downregulation of p38-MAPK expressions, indicating beneficial effects in response to PACs. Taken together, PACs display the potential to counterbalance OxS and inflammation in Fe/Asc-exposed intestinal cells, in association with an improvement of insulin sensitivity, which ameliorates lipid and glucose homeostasis.

Phenolic Compounds Impact on Rheumatoid Arthritis, Inflammatory Bowel Disease and Microbiota Modulation

Non-communicable chronic diseases (NCDs) are nowadays the principal cause of death, especially in most industrialized nations. These illnesses have increased exponentially with the consumption of diets very high in fat and sugar, not to mention stress and physical inactivity among other factors. The potential impact of suboptimal diets on NCDs’ morbidity and mortality rates brings to the forefront the necessity for a new way of improving dietary habits. The literature provides extensive scientific work that presents evidence that phenolic compounds from diets have antioxidant, anti-inflammatory and antiproliferative activities that impact human health. Gut microbiota modulation by some phenolic compounds leads to favorable changes in abundance, diversity, and in the immune system. However, polyphenol’s limited bioavailability needs to be overcome, highlighting their application in new delivery systems and providing their health benefits in well-established ways such as health maintenance, treatment or adjuvant to conventional pharmacological treatments. In this context, novel dietary approaches, including new food supplements, have emerged to prevent diseases and preserve health.

Endothelial Dysfunction and Extra-Articular Neurological Manifestations in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, inflammatory autoimmune disease that affects about 1% of the global population, with a female–male ratio of 3:1. RA preferably affects the joints, with consequent joint swelling and deformities followed by ankylosis. However, evidence has accumulated showing that patients suffering from RA can also develop extra-articular manifestations, including cardiovascular disease states, neuropathies, and multiorgan dysfunction. In particular, peripheral nerve disorders showed a consistent impact in the course of the disease (prevalence about 20%) mostly associated to vasculitis of the nerve vessels leading to vascular ischemia, axonal degeneration, and neuronal demyelination. The pathophysiological basis of this RA-associated microvascular disease, which leads to impairment of assonal functionality, is still to be better clarified. However, endothelial dysfunction and alterations of the so-called brain-nerve barrier (BNB) seem to play a fundamental role. This review aims to assess the potential mechanisms underlying the impairment of endothelial cell functionality in the development of RA and to identify the role of dysfunctional endothelium as a causative mechanism of extra-articular manifestation of RA. On the other hand, the potential impact of lifestyle and nutritional interventions targeting the maintenance of endothelial cell integrity in patients with RA will be discussed as a potential option when approaching therapeutic solutions in the course of the disease.

Autophagy Activation by Resveratrol Reduces Severity of Experimental Rheumatoid Arthritis

SCOPE

Previous work reported that dietary supplementation with resveratrol lowers synovial hyperplasia, inflammatory and oxidative damage in an antigen-induced arthritis (AIA) model. Here, it is investigated whether resveratrol can regulate the abnormal synovial proliferation by inducing autophagy and controlling the associated inflammatory response.

METHODS AND RESULTS

Animals treated with resveratrol 8 weeks before AIA induction show the highest significant signal for microtubule-associated protein 1 light chain 3 by confocal microscopy. Besides, resveratrol significantly reduces p62 expression, but it does not increase the signal of beclin-1. Also, active caspase-3 expression, as well as poly(ADP-ribose) polymerase, is upregulated in the AIA group, and is significantly reduced in resveratrol-treated AIA group. Resveratrol also mitigates angiopoietin-1 and vascular endothelial growth factor signals. Finally, resveratrol significantly reduces the serum levels of IL-1β, C reactive protein, and prostaglandin E2, as well as nuclear factor κB synovial tissue expression, which shows a significant correlation with p62 expression.

CONCLUSION

Dietary supplementation with resveratrol induces the noncanonical autophagy pathway and limits the cross-talk with inflammation, which in consequence modulates the synovial hyperplasia. Preventive strategies that incorporate dietary intervention with resveratrol may offer a potential therapeutic alternative to drugs to influence the risk of rheumatoid arthritis and influence its course.

USP13 mediates PTEN to ameliorate osteoarthritis by restraining oxidative stress, apoptosis and inflammation via AKT-dependent manner

Osteoarthritis is a chronic, systemic and inflammatory disease. However, the pathogenesis and understanding of RA are still limited. Ubiquitin-specific protease 13 (USP13) belongs to the deubiquitinating enzyme (DUB) superfamily, and has been implicated in various cellular events. Nevertheless, its potential on RA progression has little to be investigated. In the present study, we found that USP13 expression was markedly up-regulated in synovial tissue samples from patients with RA, and was down-regulated in human fibroblast-like synoviocytes (H-FLSs) stimulated by interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α) or lipopolysaccharide (LPS). We then showed that over-expressing USP13 markedly suppressed inflammatory response, oxidative stress and apoptosis in H-FLSs upon IL-1β or TNF-α challenge, whereas USP13 knockdown exhibited detrimental effects. In addition, USP13-induced protective effects were associated with the improvement of nuclear factor erythroid 2-related factor 2 (Nrf-2) and the repression of Casapse-3. Furthermore, phosphatase and tensin homolog (PTEN) expression was greatly improved by USP13 in H-FLSs upon IL-1β or TNF-α treatment, whereas phosphorylated AKT expression was diminished. In response to IL-1β or TNF-α exposure, nuclear transcription factor κB (NF-κB) signaling pathway was activated, whereas being significantly restrained in H-FLSs over-expressing USP13. Mechanistically, USP13 directly interacted with PTEN. Of note, we found that USP13-regulated cellular processes including inflammation, oxidative stress and apoptotic cell death were partly dependent on AKT activation. Furthermore, USP13 over-expression effectively inhibited osteoclastogenesis and osteoclast-associated gene expression. The in vivo experiments finally confirmed that USP13 dramatically repressed synovial hyperplasia, inflammatory cell infiltration, cartilage damage and bone loss in collagen-induced arthritis (CIA) mice via the same molecular mechanisms detected in vitro. Taken together, these findings suggested that targeting USP13 may provide feasible therapies for RA.

Knockdown of nrf2 Exacerbates TNF-α-Induced Proliferation and Invasion of Rheumatoid Arthritis Fibroblast-Like Synoviocytes through Activating JNK Pathway

Fibroblast-like synoviocytes (FLS) in the synovial tissue of rheumatoid arthritis (RA) exhibit over-proliferative and aggressive phenotypes, which participate in the pathophysiology of RA. In RA, little is known about the nonantioxidant effect of nuclear factor erythroid 2-related factor 2 (nrf2), the master regulator of redox homeostasis. In this study, we aimed to explore the expression and upstream regulatory factors of nrf2 and revealed its functions in modulating the proliferation and invasion in RA-FLS. FLS were isolated from RA and osteoarthritis patients. Expression of nrf2 in the synovial tissues and FLS was analyzed by immunohistochemistry, real-time PCR, Western blotting, and immunofluorescence staining. Cell proliferation was examined by Cell Counting Kit-8. Cell invasion was tested by transwell assay. Phosphorylation of JNK was determined by Western blotting. The results showed that nrf2 expression in the RA synovial tissues was upregulated. TNF-α promoted expression and nuclear translocation of nrf2 in RA-FLS and increased the intracellular reactive oxygen species (ROS) level. Nrf2 nuclear translocation was blocked by ROS inhibitor N-acetylcysteine. Both knockdown of nrf2 by siRNA and inhibition of nrf2 by ML385 significantly promoted the TNF-α-induced proliferation and invasion of RA-FLS. Activation of nrf2 by sulforaphane (SFN) profoundly inhibited the TNF-α-induced proliferation and invasion of RA-FLS. Knockdown of nrf2 also enhanced the TNF-α-induced matrix metalloproteinases (MMPs) expression and phosphorylation of JNK in RA-FLS. Proliferation and invasion of RA-FLS incubated with TNF-α and nrf2 siRNA were inhibited by pretreatment with JNK inhibitor SP600125. In conclusion, nrf2 is overexpressed in synovial tissues of RA patients, which may be promoted by TNF-α and ROS levels. Activation of nrf2 may suppress TNF-α-induced proliferation, invasion, and MMPs expression in RA-FLS by inhibiting JNK activation, indicating that nrf2 plays a protective role in relieving the severity of synovitis in RA. Our results might provide novel insights into the treatment of RA.

Therapeutic Potential of Reactive Oxygen Species: State of the Art and Recent Advances

In the last decade, several studies have proven that when at low concentration reactive oxygen species (ROS) show an adaptive beneficial effect and posited the idea that they can be utilized as inexpensive and convenient inducers of tissue regeneration. On the other hand, the recent discovery that cancer cells are more sensitive to oxidative damage paved the way for their use in the selective killing of tumor cells, and sensors to monitor ROS production during cancer treatment are under extensive investigation. Nevertheless, although ROS-activated signaling pathways are well established, less is known about the mechanisms underlying the switch from an anabolic to a cytotoxic response. Furthermore, a high variability in biological response is observed between different modalities of administration, cell types, donor ages, eventual concomitant diseases, and external microenvironment. On the other hand, available preclinical studies are scarce, whereas the quest for the most suitable systems for in vivo delivery is still elusive. Furthermore, new strategies to control the temporal pattern of ROS release need to be developed, if considering their tumorigenic potential. This review initially discusses ROS mechanisms of action and their potential application in stem cell biology, tissue engineering, and cancer therapy. It then outlines the state of art of ROS-based drugs and identifies challenges faced in translating ROS research into clinical practice.