NRF2: New Mechanistic Insights and Therapeutic Perspectives

Human placental mesenchymal stem cells regulate the antioxidant capacity of CD8+PD-1+ T cells through the CD73/ADO/Nrf2 pathway to protect against liver damage in mice with acute graft-versus-host disease

Graft-versus-host disease (GVHD) constitutes a severe complication that occurs after allogeneic hematopoietic stem cell transplantation (allo-HSCT), significantly reducing the survival rate of patients. Mesenchymal stem cells (MSCs) are capable of ameliorating the tissue damage caused by GVHD through exerting immunosuppressive effects; however, the relevant mechanisms require further investigation. This study used a GVHD mouse model to explore the therapeutic effects and mechanisms of human placental mesenchymal stem cells (hPMSCs) in mitigating GVHD-induced liver injury. The findings indicated that hPMSCs reduced the proportion of CD8+PD-1+ T cells in both the liver and spleen of GVHD mice, decreased reactive oxygen species (ROS) levels, and upregulated glutathione S transferase (GST) and glutathione (GSH) levels. Consistently, this led to a decrease in the expression of liver fibrosis markers, including alpha-smooth muscle actin (α-SMA) and fibronectin (FN). Moreover, CD8+PD-1+ T cells and ROS were positively correlated with α-SMA and FN, respectively, whereas GST and GSH were negatively correlated with them. hPMSCs with low expression in CD73 attenuated this effect. In vitro studies demonstrated that hPMSCs upregulated the expression of nuclear factor-E2-related factor 2 (Nrf2) via the CD73/adenosine (ADO) pathway, regulated oxidative metabolism, and reduced the number of CD8+PD-1+ T cells. The results suggested that hPMSCs contributed to the regulation of redox homeostasis and reduced the proportion of CD8+PD-1+ T cells through the CD73/ADO/Nrf2 signaling pathway, thereby alleviating liver injury associated with GVHD.

Solasodine Downregulates ABCB1 Overexpression in Multidrug Resistant Cancer Cells Via Inhibiting Nrf2/Keap1 Signaling Pathway

Multidrug-resistant (MDR) cancer cells maintain redox homeostasis to eliminate oxidative stress-mediated cell death. This study explores the effects of solasodine on regulating P-glycoprotein (P-gp) expression through the Nrf2/Keap1 signaling pathway and oxidative stress-induced sensitization of drug-resistant cancer cells to chemotherapeutics. Initially, the oxidative stress indicators such as intracellular ROS generation, the levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and gamma-H2AX (γ-H2AX) in the KBChR-8-5 drug-resistant cells were measured. Additionally, the protein expression levels of Nuclear factor erythroid 2-related factor 2 (Nrf-2), Kelch-like ECH-associated protein 1 (Keap1), and ATP Binding Cassette Subfamily B Member 1 (ABCB1)/P-gp were measured at various concentrations of solasodine (1, 5, & 10 µM) through immunofluorescence and western blot analysis. The antioxidant activities in the KBChR-8-5 cells were assessed using established protocols. In this investigation, the treatment with solasodine and doxorubicin combination showed a notable increase in intracellular ROS generation in KBChR-8-5 cells. Furthermore, this combination treatment led to enhanced nuclear condensation, elevated levels of 8-OHdG, and increased γ-H2AX foci formation in the KBChR-8-5 cells. Solasodine treatment effectively inhibited the nuclear translocation of Nrf2 and activation of the ABCB1 gene, consequently preventing overexpression of P-gp in KBChR-8-5 cells. Additionally, the combination therapy increased the lipid peroxidation levels while simultaneously reducing the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and the levels of glutathione (GSH). These results demonstrated that solasodine disrupts redox balance, and overcomes drug resistance by downregulating P-gp via regulating Nrf2/Keap1 signaling pathway in MDR cancer cells.

Effects of intermittent exposure to hypobaric hypoxia and cold on skeletal muscle regeneration: Mitochondrial dynamics, protein oxidation and turnover

Muscle injuries and the subsequent regeneration events compromise muscle homeostasis at morphological, functional and molecular levels. Among the molecular alterations, those derived from the mitochondrial function are especially relevant. We analysed the mitochondrial dynamics, the redox balance, the protein oxidation and the main protein repairing mechanisms after 9 days of injury in the rat gastrocnemius muscle. During the recovery rats were exposed to intermittent cold exposure (ICE), intermittent hypobaric hypoxia (IHH), and both simultaneous combined stimuli. Non-injured contralateral legs were also analysed to evaluate the specific effects of the three environmental exposures. Our results showed that ICE enhanced mitochondrial adaptation by improving the electron transport chain efficiency during muscle recovery, decreased the expression of regulatory subunit of proteasome and accumulated oxidized proteins. Exposure to IHH did not show mitochondrial compensation or increased protein turnover mechanisms; however, no accumulation of oxidized proteins was observed. Both ICE and IHH, when applied separately, elicited an increased expression of eNOS, which could have played an important role in accelerating muscle recovery. The combined effect of ICE and IHH led to a complex response that could potentially impede optimal mitochondrial function and enhanced the accumulation of protein oxidation. These findings underscore the nuanced role of environmental stressors in the muscle healing process and their implications for optimizing recovery strategies.

Brusatol induces ferroptosis to inhibit hepatocellular carcinoma progression by targeting ATF3

Ferroptosis is a novel form of programmed cell death that is triggered by iron-dependent lipid peroxidation. Brusatol (BRU), a natural nuclear factor erythroid 2-related factor 2 inhibitor, exhibits potent anticancer effects in various types of cancer. However, the exact mechanism of BRU in the treatment of hepatocellular carcinoma (HCC) remains unknown. The anticancer effects of BRU in HCC were detected using cell counting kit-8 and colony formation assays and a xenograft model. RNA sequencing (RNA-seq) and bioinformatics analyses of HCC cells were utilized to elucidate the mechanism underlying the effects of BRU in HCC. The levels of reactive oxygen species (ROS), glutathione (GSH), malondialdehyde (MDA), and Fe2+ were measured using assay kits. The expression of activating transcription factor 3 (ATF3) was tested using RT-qPCR, western blotting, and immunofluorescence staining. The role of ATF3 in BRU-induced ferroptosis was examined using siATF3. BRU significantly inhibited HCC cell proliferation, both in vitro and in vivo. BRU activated the ferroptosis signaling pathway and increased ATF3 expression. Furthermore, ATF3 knockdown impeded BRU-induced ferroptosis. BRU suppressed HCC growth through ATF3-mediated ferroptosis, supporting BRU as a promising therapeutic agent for HCC.

Efficacy of natural products on premature ovarian failure: a systematic review and meta-analysis of preclinical studies

OBJECTIVE

This study aims to investigate the effects of natural products on animal models of premature ovarian failure (POF).

METHODS

We conducted comprehensive literature searches and identified relevant studies that examined the protective effects of natural products on experimental POF. We extracted quantitative data on various aspects such as follicular development, ovarian function, physical indicators, oxidative stress markers, inflammatory factors, and protein changes. The data was analyzed using random-effects meta-analyses, calculating pooled standardized mean differences and 95% confidence intervals. Heterogeneity was assessed using the I2 statistic, and bias was estimated using the SYRCLE tool.

RESULTS

Among the 879 reviewed records, 25 articles met our inclusion criteria. These findings demonstrate that treatment with different phytochemicals and marine natural products (flavonoids, phenols, peptides, and alkaloids, etc.) significantly improved various aspects of ovarian function compared to control groups. The treatment led to an increase in follicle count at different stages, elevated levels of key hormones, and a decrease in atretic follicles and hormone levels associated with POF. This therapy also reduced oxidative stress (specifically polyphenols, resveratrol) and apoptotic cell death (particularly flavonoids, chrysin) in ovarian granulosa cells, although it showed no significant impact on inflammatory responses. The certainty of evidence supporting these findings ranged from low to moderate.

CONCLUSIONS

Phytochemicals and marine natural product therapy (explicitly flavonoids, phenols, peptides, and alkaloids) has shown potential in enhancing folliculogenesis and improving ovarian function in animal models of POF. These findings provide promising strategies to protect ovarian reserve and reproductive health. Targeting oxidative stress and apoptosis pathways may be the underlying mechanism.