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

Resveratrol alleviates oxidative stress caused by Streptococcus uberis infection via activating the Nrf2 signaling pathway

Due to its antioxidant properties, resveratrol may relieve the cellular oxidative injury induced by Streptococcus uberis (S. uberis) infection. However, the underlying molecular mechanisms remain unknown. Herein, we used S. uberis to challenge C57BL/6 mice or a mouse mammary epithelial cell line (EpH₄-Ev), and the regulatory molecular mechanism of resveratrol on hosts' oxidative injury were investigated. The results showed that gavage of resveratrol alleviate the inflammatory responses and oxidative injury of mammary gland tissues induced by S. uberis infection via activating Nrf2 signaling pathways. To further understand the molecular mechanism, inhibitor of Nrf2 (ML385) and siRNA targeting p62 were used in mammary epithelial cells. The findings indicated that resveratrol mediates Keap1 degradation by activating p62, induces the expression of Nrf2 and its downstream antioxidant signaling pathways, and ameliorates oxidative damage during S. uberis infection. Collectively, these outcomes suggested that resveratrol can function as an activator of the p62-Keap1/Nrf2 signaling pathway to improve oxidative injury caused by S. uberis in mammary glands as well as in EpH₄-Ev cells. Therefore, resveratrol may be useful to prevent and control S. uberis-induced bovine mastitis by relieving oxidative stress.

Potential Advantages of Bioactive Compounds Extracted From Traditional Chinese Medicine to Inhibit Bone Destructions in Rheumatoid Arthritis

Bone destruction is an important pathological feature of rheumatoid arthritis (RA), which finally leads to the serious decline of life quality in RA patients. Bone metabolism imbalance is the principal factor of bone destruction in RA, which is manifested by excessive osteoclast-mediated bone resorption and inadequate osteoblast-mediated bone formation. Although current drugs alleviate the process of bone destruction to a certain extent, there are still many deficiencies. Recent studies have shown that traditional Chinese medicine (TCM) could effectively suppress bone destruction of RA. Some bioactive compounds from TCM have shown good effect on inhibiting osteoclast differentiation and promoting osteoblast proliferation. This article reviews the research progress of bioactive compounds exacted from TCM in inhibiting bone destruction of RA, so as to provide references for further clinical and scientific research.

[Aerobic exercise combined with huwentoxin-I upregulates phase-Ⅱ detoxification enzymes to alleviate obstructive jaundice-induced central nervous system injury in mice]

OBJECTIVE

To explore the effects of aerobic exercise combined with huwentoxin-I (HWTX-I)-mediated Keap1-Nrf2-ARE pathway on phase II detoxification enzymes HO-1 and NQO1 and their protective effects against obstructive jaundice (OJ)-induced central nervous system injury in mice.

METHODS

50 male KM mice were randomly divided into blank group (GO), model group (M), aerobic exercise group (T), HWTX-I group (H), and aerobic exercise combined with HWTX-I group (TH). Mouse models of OJ were established with surgical suture for 72 h in the mice in all the groups except for the blank control group. The mice received interventions by aerobic exercise and tail vein injection of HWTX-I (0.05 μg/g) and were assessed by behavioral observation, Clark's neurological function scores, enzyme-linked immunosorbent assay (ELISA), brain tissue Nissl staining, hippocampal tissue Western blotting, and liver tissue mRNA expression profiling and sequencing.

RESULTS

The mice in group M had obvious jaundice symptoms after the operation with significantly increased Clark's neurological score (P < 0.01). Compared with those in group M, the mice in group T, group H, and group TH showed significantly decreased serum levels of ALT, AST, TBIL, and TBA (P < 0.01) with increased contents of 5-HT and BDNF and decreased contents of S100B and NSE in the hippocampus (P < 0.01). Synergistic effects between aerobic exercise and HWTX-I were noted on the above parameters except for the liver function indicators. Interventions with aerobic exercise and HWTX-I, alone or in combination, obviously lessened pathologies in the brain tissue induced by OJ, and the combined treatment produced the strongest effect. The treatment also increased the expression levels of Nrf2, HO-1, and NQO1 mRNA and protein in brain tissues (P < 0.01 or 0.05) with a synergistic effect between aerobic exercise and HWTX-I. Illumina high-throughput sequencing showed that the differentially expressed factors participated mainly in such neural regulatory pathways as neuroactive ligand-receptor interaction, GABAergic synapses, dopaminergic synapses, synaptic vesicle circulation, and axon guidance, involving tissue cell neuronal signal transduction, apoptosis inhibition, immune response, and toxicity. Aerobic exercise and HWTX-I synergistically increased the accumulation of the signal pathways related with neuron damage repair and proliferation.

CONCLUSIONS

Aerobic exercise combined with HWTX-I can up-regulate the expression of phase Ⅱ detoxification enzymes HO-1 and NQO1 through the Keap1-Nrf2-ARE pathway to protect the central nervous system against OJ-induced damage in mice.

Mst1 promotes mitochondrial dysfunction and apoptosis in oxidative stress-induced rheumatoid arthritis synoviocytes

In this study, we investigated the role of macrophage stimulating 1 (Mst1) and the AMPK-Sirt1 signaling pathway in the oxidative stress-induced mitochondrial dysfunction and apoptosis seen in rheumatoid arthritis-related fibroblast-like synoviocytes (RA-FLSs). Mst1 mRNA and protein expression was significantly higher in hydrogen peroxide (H₂O₂)-treated RA-FLSs than untreated controls. H₂O₂ treatment induced the mitochondrial apoptotic pathway by activating caspase3/9 and Bax in the RA-FLSs. Moreover, H₂O₂ treatment significantly reduced mitochondrial membrane potential and mitochondrial state-3 and state-4 respiration, but increased reactive oxygen species (ROS). Mst1 silencing significantly reduced oxidative stress-induced mitochondrial dysfunction and apoptosis in RA-FLSs. Sirt1 expression was significantly reduced in the H₂O₂-treated RA-FLSs, but was higher in the H₂O₂-treated Mst1-silenced RA-FLSs. Pretreatment with selisistat (Sirt1-specific inhibitor) or compound C (AMPK antagonist) significantly reduced the viability and mitochondrial function in H₂O₂-treated Mst1-silenced RA-FLSs by inhibiting Sirt1 function or Sirt1 expression, respectively. These findings demonstrate that oxidative stress-related upregulation and activation of Mst1 promotes mitochondrial dysfunction and apoptosis in RA-FLSs by inhibiting the AMPK-Sirt1 signaling pathway. This suggests the Mst1-AMPK-Sirt1 axis is a potential target for RA therapy.

Resveratrol targeting tau proteins, amyloid-beta aggregations, and their adverse effects: An updated review

Resveratrol (Res) is a non-flavonoid compound with pharmacological actions such as antioxidant, antiinflammatory, hepatoprotective, antidiabetes, and antitumor. This plant-derived chemical has a long history usage in treatment of diseases. The excellent therapeutic impacts of Res and its capability in penetration into blood-brain barrier have made it an appropriate candidate in the treatment of neurological disorders (NDs). Tau protein aggregations and amyloid-beta (Aβ) deposits are responsible for the induction of NDs. A variety of studies have elucidated the role of these aggregations in NDs and the underlying molecular pathways in their development. In the present review, based on the recently published articles, we describe that how Res administration could inhibit amyloidogenic pathway and stimulate processes such as autophagy to degrade Aβ aggregations. Besides, we demonstrate that Res supplementation is beneficial in dephosphorylation of tau proteins and suppressing their aggregations. Then, we discuss molecular pathways and relate them to the treatment of NDs.

Manganese porphyrin, MnTE-2-PyP, treatment protects the prostate from radiation-induced fibrosis (RIF) by activating the NRF2 signaling pathway and enhancing SOD2 and sirtuin activity

Radiation therapy is a frequently used treatment for prostate cancer patients. Manganese (III) meso-tetrakis (N-ethylpyridinium-2-yl) porphyrin (MnTE-2-PyP or T2E or BMX-010) and other similar manganese porphyrin compounds that scavenge superoxide molecules have been demonstrated to be effective radioprotectors and prevent the development of radiation-induced fibrosis (RIF). However, understanding the molecular pathway changes associated with these compounds remains limited for radioprotection. Recent RNA-sequencing data from our laboratory revealed that MnTE-2-PyP treatment activated the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway. Therefore, we hypothesize that MnTE-2-PyP protects the prostate from RIF by activating the NRF2 signaling pathway. We identified that MnTE-2-PyP is a post-translational activator of NRF2 signaling in prostate fibroblast cells, which plays a major role in fibroblast activation and myofibroblast differentiation. The mechanism of NRF2 activation involves an increase in hydrogen peroxide and a corresponding decrease in kelch-like ECH-associated protein 1 (KEAP1) levels. Activation of NRF2 signaling leads to an increase in expression of NAD(P)H dehydrogenase [quinone] 1 (NQO1), nicotinamide adenine dinucleotide (NAD+) levels, sirtuin activity (nuclear and mitochondrial), and superoxide dismutase 2 (SOD2) expression/activity. Increase in mitochondrial sirtuin activity correlates with a decrease in SOD2 (K122) acetylation. This decrease in SOD2 K122 acetylation correlates with an increase in SOD2 activity and mitochondrial superoxide scavenging capacity. Further, in human primary prostate fibroblast cells, the NRF2 pathway plays a major role in the fibroblast to myofibroblast transformation, which is responsible for the fibrotic phenotype. In the context of radiation protection, MnTE-2-PyP fails to prevent fibroblast to myofibroblast transformation in the absence of NRF2 signaling. Collectively, our results indicate that the activation of the NRF2 signaling pathway by MnTE-2-PyP is at least a partial mechanism of radioprotection in prostate fibroblast cells.

Suppression of p66Shc prevents hyperandrogenism-induced ovarian oxidative stress and fibrosis

Background

Rats with hyperandrogen-induced polycystic ovary syndrome (PCOS) have been shown to develop ovarian oxidative stress (OS) and fibrosis. The Sirt1 agonist, resveratrol, can reduce OS through inhibiting p66Shc in other models of OS.

Methods

We created a rat PCOS model with increased OS levels following treatment with one of the two androgens, dehydroepiandrosterone (DHEA) and dihydrotestosterone (DHT). The PCOS related features were determined by measurement of malondialdehyde (MDA) and superoxide dismutase (SOD) levels or by examining the reactive oxygen species (ROS) levels using the DCF-DA probe. The potential mechanisms by which p66Shc/Sirt1 mediates ovarian fibrosis were explored by western blotting, quantitative reverse transcription-PCR, immunofluorescence staining, and immunohistochemistry.

Results

Hyperandrogen dramatically augmented OS and activation of fibrotic factors in the ovary. Our data demonstrated that treatment with resveratrol enhanced Sirt1 and decreased ovarian OS as well as inhibited phosphorylation of p66Shc both in vivo and in vitro. The treatment suppressed fibrotic factor activation and improved ovarian morphology. Lentivirus- or siRNA-mediated p66Shc knockdown resulted in a dramatic enhancement of Sirt1 expression, down-regulation of ROS and suppression of fibrotic factors in granulosa cells. Moreover, p66Shc overexpression markedly increased the expression of fibrotic factors. Additionally, silencing Sirt1 induced a dramatic increase in p66Shc and enhanced activation of fibrotic factors.

Conclusions

p66Shc may be a direct target of Sirt1 for inducing ROS and thus promoting fibrosis. Further exploration of the mechanisms of p66Shc in both fibrosis and OS may provide novel therapeutic strategies that will facilitate the improvement in PCOS symptoms and reproductive functions.

Protective functions of Lycium barbarum polysaccharides in H2O2-injured vascular endothelial cells through anti-oxidation and anti-apoptosis effects

Cell injury in the cardiovascular endothelia caused by oxidative stress is among the major inducers of endothelium dysfunction and serves an important role in initiating cardiovascular diseases (CVDs). Therefore, protecting and improving the normal function of endothelial cells are considered key measures against CVDs. As a traditional Chinese medicinal component, Lycium barbarum is regarded to have high medicinal value. The present study aimed to investigate the potential anti-apoptosis and anti-oxidation effects of Lycium barbarum polysaccharides (LBPs) on injured rat artery endothelial cells, to demonstrate the experimental and medicinal values of LBPs. In the present study, the aortic endothelial cells of rats were cultivated and randomly divided into five groups: A control group, H₂O₂-injured group (H₂O₂ group), H₂O₂+LBPs (110 µg/ml) group (low-dose group, LT), H₂O₂+LBPs (220 µg/ml) group (medium-dose group, MT) and H₂O₂+LBPs (440 µg/ml) group (high-dose group, HT). Among these, the activity of superoxide dismutase (SOD), and the levels of malondialdehyde (MDA) and nitric oxide (NO) were detected by colorimetry. Additionally, the expression of B-cell lymphoma-2 (Bcl-2) and Bcl-2-associated X protein (Bax) were detected by western blotting. It was observed that SOD activity and NO content decreased while MDA content increased significantly in the H₂O₂ group (P<0.05 vs. control); that SOD activity in the MT and HT group, and NO content in all three LBP groups were increased, while MDA content in the three LBP groups was decreased, compared with the H₂O₂ group (all P<0.05); that Bcl-2 expression decreased significantly in the H₂O₂ group while the expression of Bax increased significantly compared with the control group (both P<0.05); and that Bcl-2 expression in all three LBP groups increased, while Bax expression in the MT and HT groups decreased compared with the H₂O₂ group (all P<0.05), with these altered Bax levels being statistically similar to those in the control group (P>0.05). On light microscopy, the cells in the control group exhibited spindle-shaped morphology, consistent sizes, defined boundaries, and distinct nuclei of equivalent sizes with round or oval morphology. Additionally, the chromatin in the nuclei was evenly distributed, and all cells were adhered in a paving-stone arrangement. Notably, only few cells died. Conversely, the cells in the H₂O₂ group exhibited signs of damage and enlarged gaps, and focal cells died. In the HT group, the cells once again appeared adherent and exhibited similar morphological status to the normal cells. Overall, these results indicate that LBPs serve a protective role in oxidative-injured vascular endothelial cells through anti-apoptosis and anti-oxidation effects.