Concerted action of Nrf2-ARE pathway, MRN complex, HMGB1 and inflammatory cytokines - implication in modification of radiation damage

Loss of Nrf2 aggravates ionizing radiation-induced intestinal injury by activating the cGAS/STING pathway via Pirin

Ionizing radiation (IR)-induced intestinal injury remains a major limiting factor in abdominal radiation therapy, and its pathogenesis remains unclear. In this study, mouse models of IR-induced intestinal injury were established, and the effect of IR on nuclear factor erythroid 2-related factor 2 (Nrf2) was determined. More severe IR-induced intestinal damage was observed in Nrf2 knockout (KO) mice than in wild-type mice. Then, the negative regulation of cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) signaling by Nrf2 was examined both in vivo and in vitro after IR. This was accompanied by alterations in the intestinal neutrophil and macrophage populations in mice. Subsequently, the effect of the cGAS/STING pathway on the intestinal toxicity of IR was also investigated. Moreover, the downregulation of cGAS/STING by Nrf2 via its target gene, Pirin, was confirmed using transfection assays. A rescue experiment with Pirin was also conducted using adeno-associated virus in Nrf2 KO mice. Finally, the protective effect of calcitriol against IR-induced intestinal injury, along with increased Nrf2 and Pirin levels and decreased cGAS, pSTING, and interferon-beta levels, were observed. Taken together, our results suggest that Nrf2 alleviates IR-induced intestinal injury through Pirin-mediated inhibition of the innate immunity-related cGAS/STING pathway.

Mechanisms of radiation-induced tissue damage and response

Radiation-induced tissue injury (RITI) is the most common complication in clinical tumor radiotherapy. Due to the heterogeneity in the response of different tissues to radiation (IR), radiotherapy will cause different types and degrees of RITI, which greatly limits the clinical application of radiotherapy. Efforts are continuously ongoing to elucidate the molecular mechanism of RITI and develop corresponding prevention and treatment drugs for RITI. Single-cell sequencing (Sc-seq) has emerged as a powerful tool in uncovering the molecular mechanisms of RITI and for identifying potential prevention targets by enhancing our understanding of the complex intercellular relationships, facilitating the identification of novel cell phenotypes, and allowing for the assessment of cell heterogeneity and spatiotemporal developmental trajectories. Based on a comprehensive review of the molecular mechanisms of RITI, we analyzed the molecular mechanisms and regulatory networks of different types of RITI in combination with Sc-seq and summarized the targeted intervention pathways and therapeutic drugs for RITI. Deciphering the diverse mechanisms underlying RITI can shed light on its pathogenesis and unveil new therapeutic avenues to potentially facilitate the repair or regeneration of currently irreversible RITI. Furthermore, we discuss how personalized therapeutic strategies based on Sc-seq offer clinical promise in mitigating RITI.

Puerarin ameliorates non-alcoholic fatty liver disease by inhibiting lipid metabolism through FMO5

Introduction: Pueraria lobata is traditionally used in China for treatment of non-alcoholic fatty liver disease (NAFLD). Puerarin, a functional drug extracted from Pueraria lobata, features a pharmacological activity. The present study aims to investigate the effect of puerarin intervention on NAFLD. Methods: We established an NAFLD mouse model using a high-fat diet with 60% fat and evaluated the impact of puerarin intervention. Results and discussion: Our results demonstrate that puerarin intervention significantly ameliorates lipid accumulation and protects the liver from high-fat-induced damage while reducing oxidative stress levels in the liver. Furthermore, puerarin intervention significantly downregulates the transcription levels of acetyl-CoA carboxylase (ACC1) in the liver. It also upregulates the transcription levels of carnitine palmitoyltransferase 1 (CPT1), peroxisome proliferator-activated receptor alpha (PPARα), and peroxisome proliferators-activated receptor γ coactivator alpha (PGC1α), which are related to oxidation. Furthermore, we demonstrated that flavin-containing monooxygenase (FMO5) was involved in the protective effect of puerarin against NFALD. In conclusion, the present study demonstrated the beneficial effect of puerarin on NAFLD and showed that puerarin could prevent liver injury and lipid accumulation caused by NAFLD via activating FMO5. These findings provide a new theoretical basis for applying puerarin as a therapeutic agent for NAFLD.

Protective effects of ginsenoside F2 on isoproterenol-induced myocardial infarction by activating the Nrf2/HO-1 and PI3K/Akt signaling pathways

BACKGROUND

Ginsenoside F2 (GF2) serves as the principal intestinal metabolite resulting from the oral intake of Panax ginseng and Panax quinquefolius, exhibiting antioxidative, hypolipidemic, antitumor, and anti-inflammatory properties. Nevertheless, its effect on myocardial infarction (MI) is still unknown.

PURPOSE

The purpose of this study is to investigate the protective effect and the underlying mechanisms of GF2 against isoproterenol (ISO)-induced MI.

METHODS

ISO-induced H9c2 cardiomyocytes and MI rat models were utilized as in vitro and in vivo models to evaluate the impact of anti-MI of GF2. The underlying mechanisms were investigated using a variety of methodologies, including electrocardiography, Western blot analysis, histopathological examination, immunofluorescence, immunohistochemistry, and ELISA techniques.

RESULTS

In vivo experiments, our results indicated that GF2 significantly ameliorated ISO-induced electrocardiographic (ECG) abnormalities, myocardial fiber necrosis, rupture, fibrosis of myocardial tissues, and suppressed cardiac enzyme activities. Meanwhile, GF2 notably raised the activity of antioxidant enzymes like CAT, GSH, and SOD. Furthermore, it downregulated Keap1 expression level while upregulating NQO1, Nrf2, and HO-1 expression levels. Additionally, GF2 suppressed the expression of the cleaved caspase-3 and pro-apoptotic protein Bax while promoting the expression of anti-apoptotic proteins Bcl-2, p-PI3K, and p-Akt. TUNEL fluorescence results also demonstrated that GF2 effectively inhibited cardiomyocyte apoptosis. Furthermore, consistent with the results of animal experiments, GF2 considerably attenuated ROS generation, changed apoptosis and mitochondrial function, and reduced oxidative stress in ISO-induced H9c2 cardiomyocytes through activating Nrf2/HO-1 and PI3K/Akt signaling pathways.

CONCLUSION

Taken together, GF2 ameliorated MI by preventing cardiocyte apoptosis, oxidative stress, and mitochondrial dysfunction via modulating the Nrf2/HO-1 and PI3K/Akt signaling pathways, showing potential as a treatment strategy for treating MI.

Dicliptera chinensis-derived polysaccharide enhanced the growth activity of submandibular gland cells in vitro after radiotherapy

Objective

Radiotherapy for head and neck can damage the salivary gland cells, which can easily result in xerostomia. No effective treatment for radiation-induced salivary gland dysfunction currently exists. Thus, we aimed to study the protective effect of Dicliptera chinensis polysaccharides (DCP) on the prevention of submandibular gland (SMG) cell damage caused by radiotherapy in Sprague-Dawley rats.

Design

Mechanical enzyme digestion was used to extract primary rat SMG cells. A radiation injury model was established by treating these cells with a dose of 8 Gy, followed by intervention using different DCP concentrations. The cell counting kit 8 assay was used to determine the inhibition rate of SMG cells in each group. The rates of apoptosis and cell cycle progression were detected using flow cytometry. Expression of the Mre11/Rad50/Nbs1 complex (MRN) was detected using western blotting.

Results

DCP increased the proliferation of SMG cells after irradiation, and cell growth activity positively correlated with polysaccharide concentration. Flow cytometry analysis of SMG cell apoptosis revealed that DCP markedly reduced the total apoptosis rate after irradiation, especially the early apoptosis rate. Cell cycle results suggested that DCP reduced the number of cells in the S and G2 phases after irradiation and alleviated the S and G2 blocks. Western blot results indicated that the expression of Mre11, Rad50, and Nbs1 decreased in the radiation-injured group, whereas their expression increased after DCP treatment.

Conclusions

DCP can protect the rat SMG cells after radiation and be used as a protective agent against salivary gland cell damage caused by radiotherapy.

A recombinant plasmid encoding human hepatocyte growth factor promotes healing of combined radiation-trauma skin injury involved in regulating Nrf2 pathway in mice

Combined radiation-trauma skin injury represents a severe and intractable condition that urgently requires effective therapeutic interventions. In this context, hepatocyte growth factor (HGF), a multifunctional growth factor with regulating cell survival, angiogenesis, anti-inflammation and antioxidation, may be valuable for the treatment of combined radiation-trauma injury. This study investigated the protective effects of a recombinant plasmid encoding human HGF (pHGF) on irradiated human immortalized keratinocytes (HaCaT) cells in vitro, and its capability to promote the healing of combined radiation-trauma injuries in mice. The pHGF radioprotection on irradiated HaCaT cells in vitro was assessed by cell viability, the expression of Nrf2, Bcl-2 and Bax, as well as the secretion of inflammatory cytokines. In vivo therapeutic treatment, the irradiated mice with full-thickness skin wounds received pHGF local injection. The injuries were appraised based on relative wound area, pathology, immunohistochemical detection, terminal deoxynucleotidyl transferase dUTP nick end labelling assay and cytokine content. The transfection of pHGF increased the cell viability and Nrf2 expression in irradiated HaCaT cells. pHGF also significantly upregulated Bcl-2 expression, decreased the Bax/Bcl-2 ratio and inhibited the expression of interleukin-1β and tumor necrosis factor-α in irradiated cells. Local pHGF injection in vivo caused high HGF protein expression and noticeable accelerated healing of combined radiation-trauma injury. Moreover, pHGF administration upregulated Nrf2, vascular endothelial growth factor, Bcl-2 expression, downregulated Bax expression and mitigated inflammatory response. In conclusion, the protective effect of pHGF may be related to inhibiting apoptosis and inflammation involving by upregulating Nrf2. Local pHGF injection distinctly promoted the healing of combined radiation-trauma injury and demonstrates potential as a gene therapy intervention for combined radiation-trauma injury in clinic.

Nrf-2 as a novel target in radiation induced lung injury

Radiation-induced lung injury (RILI) is a common and fatal complication of chest radiotherapy. The underlying mechanisms include radiation-induced oxidative stress caused by damage to the deoxyribonucleic acid (DNA) and production of reactive oxygen species (ROS), resulting in apoptosis of lung and endothelial cells and recruitment of inflammatory cells and myofibroblasts expressing NADPH oxidase to the site of injury, which in turn contribute to oxidative stress and cytokine production. Nuclear factor erythroid 2-related factor 2 (Nrf-2) is a vital transcription factor that regulates oxidative stress and inhibits inflammation. Studies have shown that Nrf-2 protects against radiation-induced lung inflammation and fibrosis. This review discusses the protective role of Nrf-2 in RILI and its possible mechanisms.

Activation of Nrf2 antioxidant signaling alleviates gout arthritis pain and inflammation

Excessive deposition of monosodium urate (MSU) crystal in the joint results in gout arthritis, which triggers severe pain and affects life quality. Oxidative stress is a pivotal mechanism that contributes to etiology of gout pain and inflammation. Here we investigated whether activating Nrf2, which plays important roles in regulating endogenous antioxidant response, would attenuate gout arthritis via promoting antioxidant signaling in joint tissues. Gout arthritis model was established by intra-articular injection of MSU (500 μg/ankle) into the right ankle joint of mouse. Pharmacologically activating Nrf2 by activator oltipraz (50, 100 or 150 mg/kg, intraperitoneal) at 1 h before and 5, 23, 47 h after model establishment dose-dependently inhibited joint inflammation, mechanical and heat hypersensitivities in model mice. Oltipraz (100 mg/kg) reversed gait impairments without altering locomotor activity and reduced neutrophil infiltrations in ankle joints. In vitro studies revealed oltipraz (25 μM) inhibited MSU-induced ROS production in mouse macrophages and improved mitochondrial bioenergetics impairments caused by MSU. In vivo ROS imaging combined with biochemical assays confirmed the antioxidant effects of oltipraz on model mice. Nrf2 activation inhibited pro-inflammatory cytokine overproduction in ankle joint and attenuated the overexpression and enhancement in TRPV1 channel in DRG neurons innervating hind limb. Therapeutic effects of oltipraz were abolished by inhibiting Nrf2 or in Nrf2 knockout mice. These results suggest pharmacologically activating Nrf2 alleviates gout pain, gait impairments, inflammation and peripheral sensitization via Nrf2-dependent antioxidant mechanism. Targeting Nrf2 may represent a novel treatment option for gout arthritis.

N-acetyl-l-tryptophan (NAT) ameliorates radiation-induced cell death in murine macrophages J774A.1 via regulating redox homeostasis and mitochondrial dysfunction

Ionizing radiation interacts with the immune system and induces molecular damage in the cellular milieu by generating reactive oxygen species (ROS) leading to cell death. The present study was performed to investigate the protective efficacy of N-acetyl-L-tryptophan (NAT) against gamma-radiation-induced cell death in murine macrophage J774A.1 cells. The radioprotective efficacy of NAT was evaluated in terms of cell survivability, effect on antioxidant enzyme activity, and free radicals inhibition. Radioprotective efficacy of NAT pretreatment to irradiated cells was assessed via cell cycle progression, mitochondrial membrane potential (MMP) perturbation, and apoptosis regulation using flow cytometry. Results of the study demonstrated significant radioprotective efficacy (>80%) of NAT in irradiated cells as estimated by sulforhodamine B (SRB), MTT, and clonogenic assay. Significant (p < 0.001) reduction in ROS, xanthine oxidase, and mitochondrial superoxide levels along with increment in catalase, glutathione-s-transferase, glutathione, and ATPase activities in NAT pretreated plus irradiated cells was observed as compared to the gamma-irradiated cells. Further, significant (p < 0.001) stabilization of MMP and reduction in apoptosis was also observed in NAT pretreated plus irradiated cells as compared to irradiated cells that not pretreated with NAT. The current study demonstrates that NAT pretreatment to irradiated cells protects against gamma radiation-induced cell death by reducing oxidative stress, stabilizing MMP, and inhibiting apoptosis. These observations conclusively highlight the potential of developing NAT as a prospective radioprotective agent upon further validation using in-depth preclinical assessment in cellular and animal models.

Anemonin inhibits sepsis-induced acute kidney injury via mitigating inflammation and oxidative stress

Elevated inflammation and oxidative stress (OS) are the main pathologic features of acute kidney injury (AKI)-caused by sepsis. Here, we made an investigation into the protective effects of the natural compound Anemonin (ANE) on sepsis-induced AKI both in vitro and in vivo. Lipopolysaccharide (LPS) was applied to construct an in vitro AKI model in renal tubular epithelial cells, and the septic C57BL/6J mouse model was constructed via cecal ligation and puncture (CLP). Cell viability and apoptosis were detected. The levels of p53, Bax, Bcl2, Caspase3, Caspase8, Caspase9, AMP-activated protein kinase (AMPK), Sirt-1, and forkhead box O3 were determined by Western Blot or RT-PCR. The reactive oxygen species level and OS markers were measured. Furthermore, the pathological changes of kidneys were evaluated by hematoxylin-eosin staining and immunohistochemistry. As per the information presented, ANE improved LPS-elicited apoptosis, inflammatory response, and OS in a dose-dependent pattern in renal tubular epithelial cells. Besides, ANE activated the AMPK/Sirt-1 pathway, and the AMPK inhibitor (Compound C) and Sirt-1 inhibitor (EX-527) significantly attenuated ANE-mediated protection on renal tubular epithelial cells. In vivo, ANE mitigated the levels of serum creatinine and urea nitrogen in the CLP-induced mouse sepsis model, reduced the renal tissue injury score, and attenuated OS, inflammation, and apoptosis levels in the kidney. Taken together, this study suggested that ANE has protective effects in sepsis-triggered AKI through repressing inflammation, OS, and cell apoptosis by activating the AMPK/Sirt-1 pathway.

Roles of NRF2 in DNA damage repair

PURPOSE

The transcription factor NF-E2-related factor 2 (NRF2) is a master regulator widely involved in essential cellular functions such as DNA repair. By clarifying the upstream and downstream links of NRF2 to DNA damage repair, we hope that attention will be drawn to the utilization of NRF2 as a target for cancer therapy.

METHODS

Query and summarize relevant literature on the role of NRF2 in direct repair, BER, NER, MMR, HR, and NHEJ in pubmed. Make pictures of Roles of NRF2 in DNA Damage Repair and tables of antioxidant response elements (AREs) of DNA repair genes. Analyze the mutation frequency of NFE2L2 in different types of cancer using cBioPortal online tools. By using TCGA, GTEx and GO databases, analyze the correlation between NFE2L2 mutations and DNA repair systems as well as the degree of changes in DNA repair systems as malignant tumors progress.

RESULTS

NRF2 plays roles in maintaining the integrity of the genome by repairing DNA damage, regulating the cell cycle, and acting as an antioxidant. And, it possibly plays roles in double stranded break (DSB) pathway selection following ionizing radiation (IR) damage. Whether pathways such as RNA modification, ncRNA, and protein post-translational modification affect the regulation of NRF2 on DNA repair is still to be determined. The overall mutation frequency of the NFE2L2 gene in esophageal carcinoma, lung cancer, and penile cancer is the highest. Genes (50 of 58) that are negatively correlated with clinical staging are positively correlated with NFE2L2 mutations or NFE2L2 expression levels.

CONCLUSION

NRF2 participates in a variety of DNA repair pathways and plays important roles in maintaining genome stability. NRF2 is a potential target for cancer treatment.

Radiotherapy remodels the tumor microenvironment for enhancing immunotherapeutic sensitivity

Cancer immunotherapy has transformed traditional treatments, with immune checkpoint blockade being particularly prominent. However, immunotherapy has minimal benefit for patients in most types of cancer and is largely ineffective in some cancers (such as pancreatic cancer and glioma). A synergistic anti-tumor response may be produced through the combined application with traditional tumor treatment methods. Radiotherapy (RT) not only kills tumor cells but also triggers the pro-inflammatory molecules' release and immune cell infiltration, which remodel the tumor microenvironment (TME). Therefore, the combination of RT and immunotherapy is expected to achieve improved efficacy. In this review, we summarize the effects of RT on cellular components of the TME, including T cell receptor repertoires, different T cell subsets, metabolism, tumor-associated macrophages and other myeloid cells (dendritic cells, myeloid-derived suppressor cells, neutrophils and eosinophils). Meanwhile, non-cellular components such as lactate and extracellular vesicles are also elaborated. In addition, we discuss the impact of different RT modalities on tumor immunity and issues related to the clinical practice of combination therapy.

Oxidative stress and activation of H2A.X in lung alveolar epithelial cells (A549) by nanoparticulate carbon black

Fine airborne particulate matter enter the respiratory system, induce oxidative stress and initiate DNA damage. The aim of our study was the estimation of cell viability, oxidative stress, DNA damage, cell cycle alterations and activation of histone H2A.X. Experiments were done on lung alveolar epithelial (A549) cells grown for 24 h with 200 µg mL-1 coarse carbon black (CB), or nanoparticulate CB (NPCB). Neither CB nor glutathione depletion altered cell viability, growth rates, and H2A.X expression while NPCB decreased cell viability, increased oxidative stress and DNA damage. The cell cycle was blocked at G0/G1. NPCB but not CB increased expression and activation of H2A.X at mRNA and protein levels. Co-expression data point to γH2A.X as a major NPCB target, and show the interdependence of γH2A.X and oxidative stress. We conclude, that NPCB increases γ-H2A.X expression in A549 cells at mRNA and protein levels and stimulates H2A.X (Ser139), phosphorylation, associated with oxidative stress, the DNA damage response and G1 cell cycle arrest.

Cancer-Erythrocyte Membrane-Mimicking Fe3O4 Nanoparticles and DHJS for Ferroptosis/Immunotherapy Synergism in Tumors

Ferroptosis is characterized by iron accumulation and lipid peroxidation. However, a clinical dose of Fe3O4 nanoparticles could not cause effective ferroptosis in tumors, and the mechanism is yet to be completely understood. In this study, using RNA-seq data, we found that tumor cells could feedback-activate the antioxidant system by upregulating Nrf-2 expression, thus avoiding ferroptosis caused by Fe3O4 nanoparticles. We also found that DHJS (a probe for ROS generation) can antagonize Nrf-2 expression when it synergizes with Fe3O4 nanoparticles, thus inducing ferroptosis in tumor cells. Considering these findings, we created a biomimetic hybrid cell membrane camouflaged by PLGA-loaded Fe3O4 and DHJS to treat osteosarcoma. The hybrid cell membrane endowed the core nanoparticle with the extension of blood circulation life and enhanced homologous targeting ability. In addition, DHJS and Fe3O4 in nanoparticles prompted synergistically lethal ferroptosis in cancer cells and induced macrophage M1 polarization as well as the infiltration of CD8(+) T cells and dendritic cells in tumors. In summary, this study provides novel mechanistic insights and practical strategies for ferroptosis induction of Fe3O4 nanoparticles. Meanwhile, the synthesized biomimetic nanoparticles exhibited synergistic ferroptosis/immunotherapy against osteosarcoma.

Astragaloside IV protects LO2 cells from oxidative damage caused by radiation-induced bystander effect through Akt/Nrf2 pathway

Background

The protective effects of astragaloside IV (ASIV) on various diseases are well known, but its potential impact on radiation-induced bystander effect (RIBE) has remained unclear.

Objective

This study aimed to explore the protective mechanism of ASIV against oxidative damage caused by RIBE in LO2 cells.

Methods

To construct the RIBE model, the conditioned medium from HepG2 cells irradiated with radiation was transferred to nonirradiated LO2 cells. LY294002, a commonly used phosphatidylinositol 3-kinase/Akt pathway inhibitor, was added to LO2 cells 1 h before exposing HepG2 cells to radiation. LO2 cells were then collected for analyses after RIBE exposure.

Results

The study found that ASIV significantly improved cell proliferation and promoted the recovery of mitochondrial membrane potential while reducing the rate of apoptosis. Western blot analyses demonstrated that ASIV upregulated B-cell lymphoma 2 and downregulated B-cell lymphoma 2-related X protein and cleaved-caspase 3. Measurement of reactive oxygen species, superoxide dismutase, glutathione peroxidase, and malondialdehyde levels showed that ASIV effectively restored the oxidative stress state induced by RIBE. Additionally, immunofluorescence and western blots analyses confirmed that ASIV enhanced the translocation of Nrf2 to the nucleus and activated downstream nicotinamide adenine dinucleotide phosphate: quinine oxidoreductase 1 and heme oxygenase 1. Importantly, Akt pathway inhibitor repressed ASIV-induced activation of Nrf2 and its protective effect against RIBE.

Conclusion

This study demonstrates that ASIV protects LO2 cells against oxidative damage caused by RIBE through activation of the Akt/Nrf2 pathway.

Tackling regulated cell death yields enhanced protection in lung grafts

Background: Effective preservation strategies to ameliorate lung graft ischaemia injury are needed to rescue 'extended criteria' or 'marginal' lung grafts, and to improve recipient outcomes after transplantation. Methods: Lung grafts from male Lewis rats were extracted after 40 min of cardiocirculatory death, and healthy human lung tissues were collected from patients undergoing a lobectomy. Lung samples were then preserved in a 4°C preservation solution supplemented with 0.1 nM Dexmedetomidine (Dex, α2-adrenoceptor agonist) for 16 h. In vitro, human lung epithelial A549 cells were preserved in the 4°C preservation solution with 0.1 nM Dex for 24 h, then re-cultured in the cell culture medium at 37°C to mimic the clinical scenario of cold ischaemia and warm reperfusion. Lung tissues and cells were then analysed with various techniques including western blot, immunostaining and electron microscope, to determine injuries and the protection of Dex. Results: Prolonged warm ischaemia after cardiocirculatory death initiated Rip kinase-mediated necroptosis, which was exacerbated by cold storage insult and enhanced lung graft injury. Dex supplementation significantly reduced necroptosis through upregulating Nrf2 activation and reducing oxidative stress, thereby significantly improving lung graft morphology. Dex treatment also attenuated endoplasmic reticulum stress, stabilised lysosomes and promoted cell membrane resealing function, consequently reducing cell death and inflammatory activation after hypothermic hypoxia-reoxygenation in A549 cells. Conclusions: Inhibition of regulated cell death through Dex supplementation to the graft preservation solution improves allograft quality which may aid to expand the donor lung pool and enhance lung transplant outcomes per se.

Low-Dose Non-Targeted Effects and Mitochondrial Control

Non-targeted effects (NTE) have been generally regarded as a low-dose ionizing radiation (IR) phenomenon. Recently, regarding long distant abscopal effects have also been observed at high doses of IR) relevant to antitumor radiation therapy. IR is inducing NTE involving intracellular and extracellular signaling, which may lead to short-ranging bystander effects and distant long-ranging extracellular signaling abscopal effects. Internal and "spontaneous" cellular stress is mostly due to metabolic oxidative stress involving mitochondrial energy production (ATP) through oxidative phosphorylation and/or anaerobic pathways accompanied by the leakage of O₂^- and other radicals from mitochondria during normal or increased cellular energy requirements or to mitochondrial dysfunction. Among external stressors, ionizing radiation (IR) has been shown to very rapidly perturb mitochondrial functions, leading to increased energy supply demands and to ROS/NOS production. Depending on the dose, this affects all types of cell constituents, including DNA, RNA, amino acids, proteins, and membranes, perturbing normal inner cell organization and function, and forcing cells to reorganize the intracellular metabolism and the network of organelles. The reorganization implies intracellular cytoplasmic-nuclear shuttling of important proteins, activation of autophagy, and mitophagy, as well as induction of cell cycle arrest, DNA repair, apoptosis, and senescence. It also includes reprogramming of mitochondrial metabolism as well as genetic and epigenetic control of the expression of genes and proteins in order to ensure cell and tissue survival. At low doses of IR, directly irradiated cells may already exert non-targeted effects (NTE) involving the release of molecular mediators, such as radicals, cytokines, DNA fragments, small RNAs, and proteins (sometimes in the form of extracellular vehicles or exosomes), which can induce damage of unirradiated neighboring bystander or distant (abscopal) cells as well as immune responses. Such non-targeted effects (NTE) are contributing to low-dose phenomena, such as hormesis, adaptive responses, low-dose hypersensitivity, and genomic instability, and they are also promoting suppression and/or activation of immune cells. All of these are parts of the main defense systems of cells and tissues, including IR-induced innate and adaptive immune responses. The present review is focused on the prominent role of mitochondria in these processes, which are determinants of cell survival and anti-tumor RT.

Medical Needs and Therapeutic Options for Melanoma Patients Resistant to Anti-PD-1-Directed Immune Checkpoint Inhibition

Available 4- and 5-year updates for progression-free and for overall survival demonstrate a lasting clinical benefit for melanoma patients receiving anti-PD-directed immune checkpoint inhibitor therapy. However, at least one-half of the patients either do not respond to therapy or relapse early or late following the initial response to therapy. Little is known about the reasons for primary and/or secondary resistance to immunotherapy and the patterns of relapse. This review, prepared by an interdisciplinary expert panel, describes the assessment of the response and classification of resistance to PD-1 therapy, briefly summarizes the potential mechanisms of resistance, and analyzes the medical needs of and therapeutic options for melanoma patients resistant to immune checkpoint inhibitors. We appraised clinical data from trials in the metastatic, adjuvant and neo-adjuvant settings to tabulate frequencies of resistance. For these three settings, the role of predictive biomarkers for resistance is critically discussed, as well as are multimodal therapeutic options or novel immunotherapeutic approaches which may help patients overcome resistance to immune checkpoint therapy. The lack of suitable biomarkers and the currently modest outcomes of novel therapeutic regimens for overcoming resistance, most of them with a PD-1 backbone, support our recommendation to include as many patients as possible in novel or ongoing clinical trials.

p53-Dependent Cytoprotective Mechanisms behind Resistance to Chemo-Radiotherapeutic Agents Used in Cancer Treatment

Resistance to chemoradiotherapy is the main cause of cancer treatment failure. Cancer cells, especially cancer stem cells, utilize innate cytoprotective mechanisms to protect themselves from the adverse effects of chemoradiotherapy. Here, we describe a few such mechanisms: DNA damage response (DDR), immediate early response gene 5 (IER5)/heat-shock factor 1 (HSF1) pathway, and p21/nuclear factor erythroid 2-related factor 2 (NRF2) pathway, which are regulated by the tumour suppressor p53. Upon DNA damage caused during chemoradiotherapy, p53 is recruited to the sites of DNA damage and activates various DNA repair enzymes including GADD45A, p53R2, DDB2 to repair damaged-DNA in cancer cells. In addition, the p53-IER5-HSF1 pathway protects cancer cells from proteomic stress and maintains cellular proteostasis. Further, the p53-p21-NRF2 pathway induces production of antioxidants and multidrug resistance-associated proteins to protect cancer cells from therapy-induced oxidative stress and to promote effusion of drugs from the cells. This review summarises possible roles of these p53-regulated cytoprotective mechanisms in the resistance to chemoradiotherapy.

Porcine cardiac blood - Salvia miltiorrhiza root alleviates cerebral ischemia reperfusion injury by inhibiting oxidative stress induced apoptosis through PI3K/AKT/Bcl-2/Bax signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza Bge. mixed with porcine cardiac blood (PCB-DS) is mainly employed for the treatment of brain ischemia-induced mental disturbances, palpitations and phlegm confusion based on the traditional principle of Menghe medical sect. PCB is the guide to DS and enhances the effect of DS. However, the potential mechanism of PCB-DS preventing cerebral ischemia/reperfusion injury (CIRI) from the perspective of oxidative stress induced cell apoptosis remains unknown.

AIM OF THE STUDY

To investigate the pharmacological activity and molecular mechanism of PCB-DS against CIRI.

MATERIALS AND METHODS

DS samples processed with different methods were prepared and UPLC-Q-TOF-MS/MS was employed for qualitative analysis of the respective processing product. The middle cerebral artery occlusion reperfusion model was then established to investigate the pharmacological activities of PCB-DS. Pathological changes in the rat brain were observed by triphenyl tetrazolium chloride (TTC), hematoxylin-eosin, and TUNEL staining. The levels of IL-6, IL-1β, and TNF-α were detected by ELISA to evaluate the inflammatory damage. Metabolomics of cerebrospinal fluid was further used to explore the potential mechanism of PCB-DS in preventing CIRI. Based on this, the levels of oxidative stress-related lactate dehydrogenase (LDH), reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) were determined. The protein levels of PI3K, AKT, Bcl-2, Bax, cleaved-caspase-3, and cleaved-caspase-9 proteins of the cerebral infarct zone were finally measured by western blotting.

RESULTS

Forty-seven components were identified in four processing products. Compared to DS, the content of total aqueous components in PCB-DS was significantly increased including salvianolic acid B isomer, salvianolic acid D, salvianolic acid F, and salvianolic acid H/I/J. Among the DS, DS processed with wine, DS processed with pig blood, and DS processed with porcine cardiac blood, PCB-DS best alleviated the CIRI through the neurological score, brain infarct volume, brain histopathology and the levels of inflammatory factors in the brain. Twenty-five significant metabolites in the cerebrospinal fluid were screened out between the sham and I/R groups. They were mainly involved in the beta-alanine metabolism, histidine metabolism, and lysine degradation, which indicated that PCB-DS may inhibit oxidative stress-induced apoptosis to achieve treating ischemic stroke. The results of biomedical examination showed that PCB-DS could alleviate oxidative damage, significantly downregulate the expression of Bax, cleaved caspase-3 and cleaved caspase-9, and upregulate the expression of p-PI3K, p-AKT, and Bcl-2.

CONCLUSION

In summary, this study demonstrated that PCB-DS alleviated CIRI and the molecular mechanism may be related to inhibiting the oxidative stress induced apoptosis through PI3K/AKT/Bcl-2/Bax signaling pathway.

The Nrf2/HMGB1/NF-κB axis modulates chondrocyte apoptosis and extracellular matrix degradation in osteoarthritis

Osteoarthritis (OA) is a degenerative or posttraumatic condition of the joints. In OA chondrocytes, Nrf2 functions as a stress response regulator with antioxidant and anti-inflammatory effects. This study aims to investigate the role of Nrf2 and its downstream pathway in the development of osteoarthritis. IL-1β treatment suppresses Nrf2, aggrecan, and COL2A1 levels and cell viability but promotes apoptosis in chondrocytes. IL-1β stimulation induces cell apoptosis, upregulates the mRNA expression of inflammatory factors, decreases aggrecan, COL2A1, and Bcl-2 levels but increases ADAMTS-5, ADAMTS-4, MMP13, cleaved caspase 3, and BAX levels, and promotes p65 phosphorylation. Nrf2 overexpression exerts opposite effects on IL-1β-treated chondrocytes, as demonstrated by the significant attenuation of IL-1β-induced changes in chondrocytes. By binding to the HMGB1 promoter region, Nrf2 suppresses HMGB1 expression. Similar to Nrf2 overexpression, HMGB1 knockdown also attenuates IL-1β-induced changes in chondrocytes. Notably, under IL-1β stimulation, the effects of Nrf2 overexpression or tert-butylhydroquinone (TBHQ, an activator of Nrf2) on apoptosis, inflammatory factor expression, ECM and apoptosis, and NF-κB pathway activity in chondrocytes are remarkably reversed by HMGB1 overexpression or recombinant HMGB1 (rHMGB1). Similarly, rHMGB1 could partially counteract the curative effect of TBHQ on OA damage in mice. In OA cartilage tissue samples, the level of Nrf2 is lower, while the levels of HMGB1, apoptotic, and inflammatory factors are increased compared to normal cartilage tissue samples. In conclusion, for the first time, the Nrf2/HMGB1 axis was found to modulate apoptosis, ECM degradation, inflammation and activation of NF-κB signaling in chondrocytes and OA mice.

Microbiota-Derived Natural Products Targeting Cancer Stem Cells: Inside the Gut Pharma Factory

Cancer stem cells (CSCs) have drawn much attention as important tumour-initiating cells that may also be crucial for recurrence after chemotherapy. Although the activity of CSCs in various forms of cancer is complex and yet to be fully elucidated, opportunities for therapies targeting CSCs exist. CSCs are molecularly distinct from bulk tumour cells, so they can be targeted by exploiting their signature molecular pathways. Inhibiting stemness has the potential to reduce the risk posed by CSCs by limiting or eliminating their capacity for tumorigenesis, proliferation, metastasis, and recurrence. Here, we briefly described the role of CSCs in tumour biology, the mechanisms involved in CSC therapy resistance, and the role of the gut microbiota in cancer development and treatment, to then review and discuss the current advances in the discovery of microbiota-derived natural compounds targeting CSCs. Collectively, our overview suggests that dietary intervention, toward the production of those identified microbial metabolites capable of suppressing CSC properties, is a promising approach to support standard chemotherapy.

Fyn deficiency inhibits oxidative stress by decreasing c-Cbl-mediated ubiquitination of Sirt1 to attenuate diabetic renal fibrosis

OBJECTIVE

Oxidative stress (OS) is the main cause leading to diabetic renal fibrosis. Recently, Fyn was paid much attention on OS and emerged as a pivotal player in acute kidney injury, while whether Fyn regulates oxidative stress in chronic diabetes nephropathy (DN) has not been clarified yet. The purpose of this study was to identify the role of Fyn in DN and elucidated its regulatory mechanism.

METHODS

The db/db mice and littermate control C57BKS/J mice were injected by tail vein with Fyn interfering adenovirus or Fyn overexpressing adenovirus to investigate the role of Fyn in vivo. Primary glomerular mesangial cells (GMCs) were used for in vitro studies.

RESULTS

Fyn was up-regulated in high glucose (HG)-induced GMCs and kidneys of diabetic mice. Additionally, Fyn knockdown reduced the level of OS in HG-induced GMCs and kidneys of diabetic mice, thereby ameliorating diabetic renal fibrosis. While overexpression of Fyn significantly increased the level of OS in GMCs and kidney tissues, resulting in renal damage. Moreover, Fyn deficiency exerted antioxidant effects by activating the Sirt1/Foxo3a pathway. Mechanistically, Fyn facilitated the combination of c-Cbl and Sirt1 by phosphorylating c-Cbl at Tyr⁷³¹, which triggered K48-linked polyubiquitination of Sirt1 at Lys³⁷⁷ and Lys⁵¹³ by c-Cbl and promoted Sirt1 degradation, impairing the antioxidant effects of Foxo3a.

CONCLUSIONS

Fyn deficiency promoted Foxo3a nuclear transcription via reducing the ubiquitination of Sirt1 by c-Cbl, thereby alleviating renal oxidative damage in diabetic mice. These results identified Fyn as a potential therapeutic target against DN.

Bractoppin, a BRCA1 carboxy-terminal domain (BRCT) inhibitor, suppresses tumor progression in ovarian borderline tumor organoids

Borderline ovarian tumors are a special class of ovarian tumors between benign and malignant, which are not sensitive to traditional chemotherapy regimens, and the development of target drugs is limited due to the lack of cell lines. Tumor organoids can well preserve the genetic characteristics of the primary tumor, but there are only a few reports of application in borderline tumors. In this study, we successfully generated 13 ovarian borderline tumor organoids and tested the antitumor activity of Bractoppin, a BRCA1 carboxy-terminal domain (BRCT) inhibitor. Bractoppin promotes organoid apoptosis. Mechanistically, Bractoppin can inhibit organoid cell cycle progression, inhibit the repair of DSB damage and promote tumor cell apoptosis. In addition, Bractoppin can also promote the apoptosis of ovarian cancer cell lines and inhibit the HR and NHEJ repair ability of tumor cells. We demonstrate the value of ovarian borderline tumor organoids in the exploration of molecular therapy drugs, and Bractoppin may be a valuable small molecule drug in the treatment of BOT.

Mesencephalic astrocyte-derived neurotrophic factor (MANF) prevents the neuroinflammation induced dopaminergic neurodegeneration

BACKGROUND

The excessive activation of the microglia leads to the release of inflammatory factors that contribute to neuronal cell loss and neurodegeneration in Parkinson's Disease (PD). Mesencephalic astrocyte-derived neurotrophic factor (MANF) that belongs to a newly found neurotrophic factors (NTFs) family has been reported to promote neuronal survival in the PD models. However, the effects of the MANF on neuroinflammation in PD remain unclear.

METHODS

AAV8-MANF virus was constructed to determine whether the high expression of MANF can protect the neuroinflammation-induced dopaminergic neurodegeneration in rats with 6-OHDA-induced PD. Rotarod performance test, immunofluorescent staining and western bolt were employed to evaluate the behavioral dysfunction, dopaminergic neurodegeneration, microglia activation, and signal activation. 6-OHDA treated SH-SY5Y cells and LPS treated BV-2 cells were used as the in vitro model for MANF neuroprotective and neuroinflammation mechanisms. Cell vitality and apoptosis were evaluated with MTT, CCK-8 and flow cytometric analysis. The AKT/GSK3β-Nrf2 signaling and the TNF-α/IL6 expression were measured by Western Blot.

RESULTS

Our findings indicated that the elevated MANF expression by the AAV8-MANF administration ameliorated the motor dysfunction and protected the dopaminergic neurons in the 6-OHDA treated rats. The upregulated CD11b in the rat SN caused by the 6-OHDA administration was significantly attenuated by the pretreatment of the AAV8-MANF. Furthermore, the levels of p-AKT, p-GSK3β, BCL-2, and Nrf-2 were upregulated by the high expression of the MANF. Under the oxidative stress of the 6-OHDA, the MANF significantly reduced the apoptotic effect of the TNF-α on the SH-SY5Y cells. In the LPS treated BV-2 cells, the MANF reduced the production of the TNF-α and IL-6, via enhancing the Nrf-2, p-Akt, p-GSK3β, and p-NF-κβ level.

CONCLUSIONS

These results suggested that the MANF prevented the dopaminergic neurodegeneration caused by the microglia activation in PD via activation of the AKT/GSK3β-Nrf-2 signaling axis.

Sevoflurane reduces lipopolysaccharide-induced apoptosis and pulmonary fibrosis in the RAW264.7 cells and mice models to ameliorate acute lung injury by eliminating oxidative damages

Objectives

Sevoflurane is identified as an effective candidate drug for acute lung injury (ALI) treatment, but its curing effects and detailed mechanisms have not been fully disclosed. The present study was designed to resolve this academic issue.

Methods

The ALI mice models were established, and Hematoxylin-eosin staining assay was performed to examine tissue morphologies. Cell viability was determined by CCK-8 assay, and Annexin V-FITC/PI double staining assay was used to examine cell apoptosis. The expression levels of proteins were determined by performing Western Blot analysis and immunofluorescence staining assay. ROS levels were examined by using DCFH-DA staining assay.

Results

In this study, we investigated this issue and the ALI models were respectively established by treating the BALB/c mice and the murine macrophage cell line RAW264.7 with different concentrations of lipopolysaccharide (LPS) in vivo and in vitro, which were subsequently subjected to sevoflurane co-treatment. The results showed that sevoflurane reduced LPS-induced ALI in mice and suppressed LPS-triggered oxidative stress and apoptotic cell death in the RAW264.7 cells. Interestingly, we evidenced that the elimination of reactive oxygen species (ROS) by N-acetyl-L-cysteine (NAC) reversed LPS-induced cell apoptosis in RAW264.7 cells. Then, we verified that sevoflurane suppressed oxidative damages to restrain LPS-induced apoptotic cell death in the RAW264.7 cells through activating the anti-oxidant Keap1/Nrf2 pathway. Mechanistically, sevoflurane down-regulated Keap1 and upregulated Nrf2 in nucleus to activate the downstream anti-oxidant signaling cascades, which further ameliorated LPS-induced cell apoptosis and lung injury by eliminating oxidative damages.

Discussion

Taken together, our study illustrated that the sevoflurane attenuates LPS-induced ALI by inhibiting oxidative stress-mediated apoptotic cell death and inflammation, and the Keap1/Nrf2 pathway played an important role in this process.

NMN ameliorated radiation induced damage in NRF2-deficient cell and mice via regulating SIRT6 and SIRT7

Risk of cancer often increases with aging, and radiotherapy is an essential component of treatment. As for abdominal and pelvic cancer, radiotherapy always inevitably causes injury to intestines through direct DNA damage or overload of reactive oxygen species (ROS). Nuclear factor erythroid 2-related factor 2 (NRF2) has been identified as a key protective factor against ionizing-radiation induced damage through promoting DNA damage repair and antioxidant modulation. However, the level of NRF2 always decreases with aging. Here, we demonstrated that NRF2 deficiency aggravated cellular DNA damage and the intestinal pathological lesion. Overexpression of SIRT6 or SIRT7 could improve cell proliferation and protect against radiation injury in NRF2 knock-out (KO) cells by modulating oxidative-stress and DNA damage repair. Consistently, supplement of nicotinamide mononucleotide (NMN), the agonist of sirtuins, increased the level of SIRT6 and SIRT7 in NRF2 KO cells, concomitant with reduced cellular ROS level and ameliorated DNA damage. In vivo, long-term oral administration of NMN attenuated the radiation-induced injury of jejunum, increased the number of intestinal stem cells, and promoted the ability of intestinal proliferation in NRF2-/- mice. Together, our results indicated that SIRT6 and SIRT7 had involved in scavenging ROS and repairing DNA damage, and NMN could be a promising candidate for preventing radiation damage when NRF2 is lacking.

Roles of Oxidative Stress and Inflammation in Vascular Endothelial Dysfunction-Related Disease

Oxidative stress and chronic inflammation play an important role in the pathogenesis of atherosclerosis. Atherosclerosis develops as the first step of vascular endothelial dysfunction induced by complex molecular mechanisms. Vascular endothelial dysfunction leads to oxidative stress and inflammation of vessel walls, which in turn enhances vascular endothelial dysfunction. Vascular endothelial dysfunction and vascular wall oxidative stress and chronic inflammation make a vicious cycle that leads to the development of atherosclerosis. Simultaneously capturing and accurately evaluating the association of vascular endothelial function with oxidative stress and inflammation would be useful for elucidating the pathophysiology of atherosclerosis, determining treatment efficacy, and predicting future cardiovascular complications. Intervention in both areas is expected to inhibit the progression of atherosclerosis and prevent cardiovascular complications.

Radiotherapy combined with immunotherapy: the dawn of cancer treatment

Radiotherapy (RT) is delivered for purposes of local control, but can also exert systemic effect on remote and non-irradiated tumor deposits, which is called abscopal effect. The view of RT as a simple local treatment has dramatically changed in recent years, and it is now widely accepted that RT can provoke a systemic immune response which gives a strong rationale for the combination of RT and immunotherapy (iRT). Nevertheless, several points remain to be addressed such as the interaction of RT and immune system, the identification of the best schedules for combination with immunotherapy (IO), the expansion of abscopal effect and the mechanism to amplify iRT. To answer these crucial questions, we roundly summarize underlying rationale showing the whole immune landscape in RT and clinical trials to attempt to identify the best schedules of iRT. In consideration of the rarity of abscopal effect, we propose that the occurrence of abscopal effect induced by radiation can be promoted to 100% in view of molecular and genetic level. Furthermore, the “radscopal effect” which refers to using low-dose radiation to reprogram the tumor microenvironment may amplify the occurrence of abscopal effect and overcome the resistance of iRT. Taken together, RT could be regarded as a trigger of systemic antitumor immune response, and with the help of IO can be used as a radical and systemic treatment and be added into current standard regimen of patients with metastatic cancer.

Relationship between lifespan and somatic mutation in D. melanogaster after treatment with chlorophyllin

Sodium copper chlorophyllin (SCC) has a genetic damage inhibitory capacity due to its antioxidant action. For this reason, it was considered to investigate its role in the life span of Drosophila melanogaster and its relationship with the frequency of somatic mutation induced by gamma rays. Results indicated that SCC alone prolonged the lifespan only in females, but in combination with 20 Gy of gamma rays, the aging delay in both sexes was significant. In addition to confirming that the porphyrin reduces the frequency of mutation, the individuals with the highest mutation load are the individuals who die more quickly, and once they are eliminated, the survivor individuals treated with 20 Gy or with SCC + 20 Gy, died at the same rate. The results together indicate that SCC not only inhibits induced genetic damage, but it also has beneficial effects that probably cause an aging delay of the treated population that need to be investigated.

HMGB3 inhibition by miR-142-3p/sh-RNA modulates autophagy and induces apoptosis via ROS accumulation and mitochondrial dysfunction and reduces the tumorigenic potential of human breast cancer cells

AIMS

High mobility group box (HMGB) family proteins, HMGB1, HMGB2, HMGB3, and HMGB4 are oncogenic. The oncogenic nature of HMGB1 is characterized by its association with autophagy, ROS, and MMP. Since HMGB3 is its paralog, we hypothesized that it might also modulate autophagy, ROS, and MMP. Hence, we targeted HMGB3 using its shRNA or miR-142-3p and assessed the changes in autophagy, ROS, MMP, and tumorigenic properties of human breast cancer cells.

MAIN METHODS

Cell viability was assessed by resazurin staining and annexin-V/PI dual staining was used for confirming apoptosis. Colony formation, transwell migration, invasion and luciferase reporter (for miRNA-target validation) assays were also performed. ROS and MMP were detected using DHE and MitoTracker dyes, respectively. A zebrafish xenograft model was used to assess the role of miR-142-3p on in vivo metastatic potential of breast cancer cells.

KEY FINDINGS

Breast cancer tissues from Indian patients and TCGA samples exhibit overexpression of HMGB3. miR-142-3p binds to 3' UTR of HMGB3, leading to its downregulation that subsequently inhibits colony formation and induces apoptosis involving increased ROS accumulation and decreased MMP, phospho-mTOR and STAT3. Our findings show that HMGB3 is directly involved in the miR-142-3p-mediated disruption of autophagy and induction of apoptotic cell death via modulation of LC3, cleaved PARP and Bcl-xL. In addition, miR-142-3p inhibited migration, invasion and metastatic potential of breast cancer cells.

SIGNIFICANCE

Our findings highlighted the role of HMGB3, for the first time, in the modulation of autophagy and apoptosis in human breast cancer cells, and these results have therapeutic implications.

Genomic landscape of chemical-induced lung tumors under Nrf2 different expression levels

The transcription factor Nrf2 plays a crucial role in the anti-oxidative stress response, protection of DNA from injury, and DNA repair mechanisms. Nrf2 activity reduces cancer initiation, but how Nrf2 affects whole-genome alterations upon carcinogenic stimulus remains unexplored. Although recent genome-wide analysis using next-generation sequencing revealed landscapes of nucleotide mutations and copy number alterations in various human cancers, genomic changes in murine cancer models have not been thoroughly examined. We elucidated the relationship between Nrf2 expression levels and whole exon mutation patterns using an ethyl-carbamate (urethane)-induced lung carcinogenesis model employing Nrf2-deficient and Keap1-kd mice, the latter of which express high levels of Nrf2. Exome analysis demonstrated that single nucleotide and trinucleotide mutation patterns and the Kras mutational signature differed significantly and were dependent on the expression level of Nrf2. The Nrf2-deficient tumors exhibited fewer copy number alterations relative to the Nrf2-wt and Keap1-kd tumors. The observed trend in genomic alterations likely prevented the Nrf2-deficient tumors from progressing into malignancy. For the first time, we present whole-exome sequencing results for chemically-induced lung tumors in the Nrf2 gain or loss of function mouse models. Our results demonstrate that different Nrf2 expression levels lead to distinct gene mutation patterns that underly different oncogenic mechanisms in each tumor genotype.

Endurance exercise attenuates juvenile irradiation-induced skeletal muscle functional decline and mitochondrial stress

BACKGROUND

Radiotherapy is commonly used to treat childhood cancers and can have adverse effects on muscle function, but the underlying mechanisms have yet to be fully elucidated. We hypothesized that endurance exercise following radiation treatment would improve skeletal muscle function.

METHODS

We utilized the Small Animal Radiation Research Platform (SARRP) to irradiate juvenile male mice with a clinically relevant fractionated dose of 3× (every other day over 5 days) 8.2 Gy X-ray irradiation locally from the knee to footpad region of the right hindlimb. Mice were then singly housed for 1 month in cages equipped with either locked or free-spinning voluntary running wheels. Ex vivo muscle contractile function, RT-qPCR analyses, resting cytosolic and sarcoplasmic reticulum (SR) store Ca2+ levels, mitochondrial reactive oxygen species levels (MitoSOX), and immunohistochemical and biochemical analyses of muscle samples were conducted to assess the muscle pathology and the relative therapeutic impact of voluntary wheel running (VWR).

RESULTS

Irradiation reduced fast-twitch extensor digitorum longus (EDL) muscle-specific force by 27% compared to that of non-irradiated mice, while VWR post-irradiation improved muscle-specific force by 37%. Radiation treatment similarly reduced slow-twitch soleus muscle-specific force by 14% compared to that of non-irradiated mice, while VWR post-irradiation improved specific force by 18%. We assessed intracellular Ca2+ regulation, oxidative stress, and mitochondrial homeostasis as potential mechanisms of radiation-induced pathology and exercise-mediated rescue. We found a significant reduction in resting cytosolic Ca2+ concentration following irradiation in sedentary mice. Intriguingly, however, SR Ca2+ store content was increased in myofibers from irradiated mice post-VWR compared to mice that remained sedentary. We observed a 73% elevation in the overall protein oxidization in muscle post-irradiation, while VWR reduced protein nitrosylation by 35% and mitochondrial reactive oxygen species (ROS) production by 50%. Finally, we found that VWR significantly increased the expression of PGC1α at both the transcript and protein levels, consistent with an exercise-dependent increase in mitochondrial biogenesis.

CONCLUSIONS

Juvenile irradiation stunted muscle development, disrupted proper Ca2+ handling, damaged mitochondria, and increased oxidative and nitrosative stress, paralleling significant deficits in muscle force production. Exercise mitigated aberrant Ca2+ handling, mitochondrial homeostasis, and increased oxidative and nitrosative stress in a manner that correlated with improved skeletal muscle function after radiation.

Keap1 as Target of Genistein on Nrf2 Signaling Pathway Antagonizing Aβ induced Oxidative Damage of Cerebrovascular Endothelial Cells

BACKGROUND

β-amyloid peptides (Aβ) induced oxidative damage contributes to the pathogenesis of neurodegenerative diseases and cerebrovascular system is more vulnerable to oxidative stress. Our earlier study showed a clue that Genistein (Gen) might activate Nf-E2 related factor 2 (Nrf2) pathway to protect cerebrovascular cells from oxidative damage induced by Aβ, but the specific mechanisms and regulation targets are unclear.

OBJECTIVE

In this study, the anti-oxidative effects and the possible targets of Gen on regulating Nrf2 pathway in bEnd.3 cells were investigated. Cells were divided into control, Aβ25-35, Gen and Gen+Aβ25-35 groups.

METHODS

Cell viability, levels of malondialdehyde (MDA), Superoxide Dismutase (SOD) activity and nitrotyrosine were evaluated. Moreover, mRNA and/or protein expressions of Nrf2 and kelch-like ECH-associated protein 1 (Keap1) were measured. Then we transfected Keap1 over-expressed plasmid into bEnd.3 cells and measured the protein expressions of Nrf2 pathway related factors. Data showed that Gen could inhibit the over-production of MDA and nitrotyrosine and activate SOD activity. Besides we got the phenomenon that Gen could up-regulate the mRNA and protein expressions of Nrf2 and down-regulate Keap1 protein expression, the Keap1 over-expressed plasmid study indicated that the up-regulation of Nrf2 protein expression induced by pretreatment of Gen could be blocked by the transfection of Keap1 over-expressed plasmid, and the same results also occurred in Nrf2 downstream factors.

CONCLUSION

Gen could alleviate the cerebrovascular cells oxidative damage induced by Aβ25-35 through regulating Nrf2 pathway, and Keap1 might be one of the targets of Gen on activating Nrf2 pathway.

ADSC-Exosomes Alleviate MTX-induced Rat Neuronal Damage by Activating Nrf2-ARE Pathway

The aim of this study was to analyze the efficacy and underlying mechanism of adipose-derived mesenchymal stem cell exosome (ADSC-exosomes)-mediated protection on methotrexate (MTX)-induced neuronal damage. We established a H₂O₂-induced oxidative stress model in vitro, as well as an MTX-induced neuronal damage rat model in vivo. We analyzed the effects of ADSC-exosomes on neuronal damage and Nrf2-ARE signaling pathway in rats and related mechanisms. The morphological and functional recovery of rat hippocampal neurons by ADSC-exosomes was examined by Nissl staining and modified neurological severity score (mNSS) score. The activation of Nrf2-ARE pathway effectively inhibited H₂O₂-induced oxidative stress. ADSC-exosomes treatment restored the activity of hippocampal neuronal cells, reduced ROS production, and inhibited hippocampal neuronal cells apoptosis. In in vivo experiments, ADSC-exosomes ameliorates MTX-induced hippocampal neuron damage by triggering Nrf2-ARE pathway, decreasing IL-6, IFN-, and TNF-a levels and TUNEL positive cells in hippocampus, and repairing hippocampal neuronal cell damage. ADSC-exosomes ameliorated MTX-induced neuronal damage and suppressed oxidative stress induced by neuronal damage through the activation of Nrf2-ARE signaling pathway.

Pathway Phenotypes Underpinning Depression, Anxiety, and Chronic Fatigue Symptoms Due to Acute Rheumatoid Arthritis: A Precision Nomothetic Psychiatry Analysis

Rheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disorder which affects the joints in the wrists, fingers, and knees. RA is often associated with depressive and anxiety symptoms as well as chronic fatigue syndrome (CFS)-like symptoms. This paper examines the association between depressive symptoms (measured with the Beck Depression Inventory, BDI), anxiety (Hamilton Anxiety Rating Scale, HAMA), CFS-like (Fibro-fatigue Scale) symptoms and immune-inflammatory, autoimmune, and endogenous opioid system (EOS) markers, and lactosylcer-amide (CD17) in RA. The serum biomarkers were assayed in 118 RA and 50 healthy controls. Results were analyzed using the new precision nomothetic psychiatry approach. We found significant correlations between the BDI, FF, and HAMA scores and severity of RA, as assessed with the DAS28-4, clinical and disease activity indices, the number of tender and swollen joints, and patient and evaluator global assessment scores. Partial least squares analysis showed that 69.7% of the variance in this common core underpinning psychopathology and RA symptoms was explained by immune-inflammatory pathways, rheumatoid factor, anti-citrullinated protein antibodies, CD17, and mu-opioid receptor levels. We constructed a new endophenotype class comprising patients with very high immune-inflammatory markers, CD17, RA, affective and CF-like symptoms, and tobacco use disorder. We extracted a reliable and replicable latent vector (pathway phenotype) from immune data, psychopathology, and RA-severity scales. Depression, anxiety, and CFS-like symptoms due to RA are manifestations of the phenome of RA and are mediated by the effects of the same immune-inflammatory, autoimmune, and other pathways that underpin the pathophysiology of RA.

An Oligomeric Sulfated Hyaluronan and Silk-Elastinlike Polymer Combination Protects against Murine Radiation Induced Proctitis

Semisynthetic glycosaminoglycan ethers (SAGEs) are short, sulfated hyaluronans which combine the natural properties of hyaluronan with chemical sulfation. In a murine model, SAGEs provide protection against radiation induced proctitis (RIP), a side effect of lower abdominal radiotherapy for cancer. The anti-inflammatory effects of SAGE have been studied in inflammatory diseases at mucosal barrier sites; however, few mechanisms have been uncovered necessitating high throughput methods. SAGEs were combined with silk-elastinlike polymers (SELPs) to enhance rectal accumulation in mice. After high radiation exposure to the lower abdominal area, mice were followed for 3 days or until they met humane endpoints, before evaluation of behavioral pain responses and histological assessment of rectal inflammation. RNA sequencing was conducted on tissues from the 3-day cohort to determine molecular mechanisms of SAGE–SELP. After 3 days, mice receiving the SAGE–SELP combination yielded significantly lowered pain responses and amelioration of radiation-induced rectal inflammation. Mice receiving the drug–polymer combination survived 60% longer than other irradiated mice, with a fraction exhibiting long term survival. Sequencing reveals varied regulation of toll like receptors, antioxidant activities, T-cell signaling, and pathways associated with pain. This investigation elucidates several molecular mechanisms of SAGEs and exhibits promising measures for prevention of RIP.

Preventive effect of sanguinarine on intestinal injury in mice exposed to whole abdominal irradiation

Intestinal injury is one of the major side effects that are induced by medical radiation exposure, and has limited effective therapies. In this study, we investigated the beneficial effects of sanguinarine (SAN) on intestinal injury induced by ionizing radiation (IR) both in vitro and in vivo. Mice were exposed to whole abdominal irradiation (WAI) to mimic clinical scenarios. SAN was injected intraperitoneally to mitigate IR-induced injury. Histological examination was performed to assess the tissue injuries of the spleen and small intestine. A small intestinal epithelial cell line-6 (IEC-6) was analyzed for its viability and apoptosis in vitro under different treatments. Inflammation-related pathways and serum inflammatory cytokines were detected via Western blot analysis and ELISA, respectively. High-throughput sequencing was used to characterize the gut microbiota profile. High-performance liquid chromatography was performed to assess short-chain fatty acid contents in the colon. In vitro, SAN pretreatment protected cell viability and reduced apoptosis in IEC-6 cells. In vivo, SAN pretreatment protected immune organs, alleviated intestinal injury, and promoted intestinal recovery. SAN also reduced the levels of inflammatory cytokines, suppressed high mobility group box 1 (HMGB1)/ Toll-like receptor 4 (TLR4) pathway activation, and modulated gut microbiota composition. Our findings demonstrate that the beneficial properties of SAN alleviated intestinal radiation injury. Thus, SAN represents a therapeutic option for protecting against IR-induced intestinal injury in preclinical settings.

Oncogenic KRAS drives radioresistance through upregulation of NRF2-53BP1-mediated non-homologous end-joining repair

KRAS-activating mutations are oncogenic drivers and are correlated with radioresistance of multiple cancers, including colorectal cancer, but the underlying precise molecular mechanisms remain elusive. Herein we model the radiosensitivity of isogenic HCT116 and SW48 colorectal cancer cell lines bearing wild-type or various mutant KRAS isoforms. We demonstrate that KRAS mutations indeed lead to radioresistance accompanied by reduced radiotherapy-induced mitotic catastrophe and an accelerated release from G2/M arrest. Moreover, KRAS mutations result in increased DNA damage response and upregulation of 53BP1 with associated increased non-homologous end-joining (NHEJ) repair. Remarkably, KRAS mutations lead to activation of NRF2 antioxidant signaling to increase 53BP1 gene transcription. Furthermore, genetic silencing or pharmacological inhibition of KRAS, NRF2 or 53BP1 attenuates KRAS mutation-induced radioresistance, especially in G1 phase cells. These findings reveal an important role for a KRAS-induced NRF2-53BP1 axis in the DNA repair and survival of KRAS-mutant tumor cells after radiotherapy, and indicate that targeting NRF2, 53BP1 or NHEJ may represent novel strategies to selectively abrogate KRAS mutation-mediated radioresistance.

The Evolving Concept of Neuro-Thromboinflammation for Neurodegenerative Disorders and Neurotrauma: A Rationale for PAR1-Targeting Therapies

Interest in the role of coagulation and fibrinolysis in the nervous system was active in several laboratories dating back before cloning of the functional thrombin receptor in 1991. As one of those, our attention was initially on thrombin and plasminogen activators in synapse formation and elimination in the neuromuscular system, with orientation towards diseases such as amyotrophic lateral sclerosis (ALS) and how clotting and fibrinolytic pathways fit into its pathogenesis. This perspective is on neuro-thromboinflammation, emphasizing this emerging concept from studies and reports over more than three decades. It underscores how it may lead to novel therapeutic approaches to treat the ravages of neurotrauma and neurodegenerative diseases, with a focus on PAR1, ALS, and parmodulins.

Role of Mitochondria in Radiation Responses: Epigenetic, Metabolic, and Signaling Impacts

Until recently, radiation effects have been considered to be mainly due to nuclear DNA damage and their management by repair mechanisms. However, molecular biology studies reveal that the outcomes of exposures to ionizing radiation (IR) highly depend on activation and regulation through other molecular components of organelles that determine cell survival and proliferation capacities. As typical epigenetic-regulated organelles and central power stations of cells, mitochondria play an important pivotal role in those responses. They direct cellular metabolism, energy supply and homeostasis as well as radiation-induced signaling, cell death, and immunological responses. This review is focused on how energy, dose and quality of IR affect mitochondria-dependent epigenetic and functional control at the cellular and tissue level. Low-dose radiation effects on mitochondria appear to be associated with epigenetic and non-targeted effects involved in genomic instability and adaptive responses, whereas high-dose radiation effects (>1 Gy) concern therapeutic effects of radiation and long-term outcomes involving mitochondria-mediated innate and adaptive immune responses. Both effects depend on radiation quality. For example, the increased efficacy of high linear energy transfer particle radiotherapy, e.g., C-ion radiotherapy, relies on the reduction of anastasis, enhanced mitochondria-mediated apoptosis and immunogenic (antitumor) responses.

Etoposide, an anticancer drug involved in therapy-related secondary leukemia: Enzymes at play

Etoposide is a semi-synthetic glycoside derivative of podophyllotoxin, also known as VP-16. It is a widely used anticancer medicine in clinics. Unfortunately, high doses or long-term etoposide treatment can induce therapy-related leukemia. The mechanism by which etoposide induces secondary hematopoietic malignancies is still unclear. In this article, we review the potential mechanisms of etoposide induced therapy-related leukemia. Etoposide related leukemogenesis is known to depend on reactive oxidative metabolites of etoposide, notably etoposide quinone, which interacts with cellular proteins such as topoisomerases II (TOP2), CREB-binding protein (CREBBP), and T-Cell Protein Tyrosine Phosphatase (TCPTP). CYP3A4 and CYP3A5 metabolize etoposide to etoposide catechol, which readily oxidizes to etoposide quinone. As a poison of TOP2 enzymes, etoposide and its metabolites induce DNA double-stranded breaks (DSB), and the accumulation of DSB triggers cell apoptosis. If the cell survives, the DSB gives rise to the likelihood of faulty DNA repair events. The gene translocation could occur in mixed-lineage leukemia (MLL) gene, which is well-known in leukemogenesis. Recently, studies have revealed that etoposide metabolites, especially etoposide quinone, can covalently bind to cysteines residues of CREBBP and TCPTP enzymes, . This leads to enzyme inhibition and further affects histone acetylation and phosphorylation of the JAK-STAT pathway, thus putatively altering the proliferation and differentiation of hematopoietic stem cells (HSC). In brief, current studies suggest that etoposide and its metabolites contribute to etoposide therapy-related leukemia through TOP2 mediated DSB and impairs specific enzyme activity, such as CREBBP and TCPTP.

CD68+ Macrophage Infiltration Associates With Poor Outcome of HPV Negative Oral Squamous Carcinoma Patients Receiving Radiation: Poly(I:C) Enhances Radiosensitivity of CAL-27 Cells but Promotes Macrophage Recruitment Through HMGB1

Patients with human papillomavirus (HPV) negative oral squamous cell carcinoma (OSCC) generally have poor clinical outcomes and worse responses to radiotherapy. It is urgent to explore the underlining mechanisms of the distinct prognoses between HPV negative and HPV positive OSCC and to develop effective therapy strategy to increase the survival rate of HPV negative OSCC patients. We conducted a retrospective cohort of 99 resected OSCC patients to evaluate the prognosis of HPV negative and HPV positive OSCC patients receiving radiation or not. We further addressed the association of CD68⁺ macrophage infiltration with HPV status and the effects on survival of OSCC patients. We also used the TCGA-OSCC cohort for further verification. Based on the cohort study, we applied a synthetic dsRNA polymer, polyriboinosinic-polyribocytidylic acid (poly(I:C)), on CAL-27 (HPV negative OSCC cells). We co-cultured its condition medium with THP-1 derived macrophage and examined the cytokines and macrophage migration. We found that high CD68⁺ macrophage infiltration associated with poor overall survival in HPV negative OSCC patients receiving radiation. In vitro, poly(I:C) could induce apoptosis and enhance the radiosensitivity, but increase macrophage recruitment. Targeting HMGB1 could inhibit IL-6 induction and macrophage recruitment. Our findings indicated that CD68⁺ macrophage might play an important role in the outcomes of HPV negative OSCC patients receiving radiation. Our findings also suggested that radiation combined poly(I:C) might be a potential therapy strategy to increase the radiation response and prognosis of HPV negative OSCC. Notably, HMGB1 should be targeted to inhibit macrophage recruitment and enhance overall therapy effects.

A hypothesis for the pathogenesis of radiation-induced oral mucositis: when biological challenges exceed physiologic protective mechanisms. Implications for pharmacological prevention and treatment

Oral mucositis (OM) remains a significant unmet need for patients being treated with standard concomitant chemoradiation (CRT) regimens for head and neck cancers (HNC). OM's pathogenesis is complex and includes both direct and indirect damage pathways. In this paper, the field is reviewed with emphasis on the initiating and sustaining role of oxidative stress on OM's pathobiology. A hypothesis is presented which suggests that based on OM's clinical and biological trajectory, mucosal damage is largely the consequence of cumulative CRT-induced biological changes overwhelming physiologic self-protective mechanisms. Furthermore, an individual's ability to mount and maintain a protective response is dependent on interacting pathways which are primarily determined by a multiplex consisting of genomics, epigenomics, and microbiomics. Effective biologic or pharmacologic OM interventions are likely to supplement or stimulate existing physiologic damage-control mechanisms.

Anti-inflammatory mechanisms of suppressors of cytokine signaling target ROS via NRF-2/thioredoxin induction and inflammasome activation in macrophages

Suppressors of cytokine signaling (SOCS) exhibit diverse anti-inflammatory effects. Since ROS acts as a critical mediator of inflammation, we have investigated the anti-inflammatory mechanisms of SOCS via ROS regulation in monocytic/macrophagic cells. Using PMA-differentiated monocytic cell lines and primary BMDMs transduced with SOCS1 or shSOCS1, the LPS/TLR4-induced inflammatory signaling was investigated by analyzing the levels of intracellular ROS, antioxidant factors, inflammasome activation, and pro-inflammatory cytokines. The levels of LPS-induced ROS and the production of pro-inflammatory cytokines were notably down-regulated by SOCS1 and up-regulated by shSOCS1 in an NAC-sensitive manner. SOCS1 up-regulated an ROS-scavenging protein, thioredoxin, via enhanced expression and binding of NRF-2 to the thioredoxin promoter. SOCS3 exhibited similar effects on NRF-2/thioredoxin induction, and ROS downregulation, resulting in the suppression of inflammatory cytokines. Notably thioredoxin ablation promoted NLRP3 inflammasome activation and restored the SOCS1-mediated inhibition of ROS and cytokine synthesis induced by LPS. The results demonstrate that the anti-inflammatory mechanisms of SOCS1 and SOCS3 in macrophages are mediated via NRF-2-mediated thioredoxin upregulation resulting in the downregulation of ROS sig-nal. Thus, our study supports the anti-oxidant role of SOCS1 and SOCS3 in the exquisite regulation of macrophage activation under oxidative stress.

NO, way to go: critical amino acids to replenish nitric oxide production in treating mucositis

PURPOSE OF REVIEW

There is still an unmet need for preventive and treatment strategies for chemotherapy-induced and radiotherapy-induced mucositis and its associated systemic inflammatory response (SIR) in cancer patients. Because of citrulline depletion due to cytotoxic therapy, nitric oxide (NO) production can be reduced, limiting its effect in many physiological processes. Restoring NO production could relieve mucositis severity by supporting host damage control mechanisms. Amino acids glutamine, arginine and citrulline are involved in NO production. This review including recent literature of preclinical and clinical studies will discuss the potential benefits of glutamine, arginine and citrulline on mucositis development with focus on NO production.

RECENT FINDINGS

Mucositis severity is more defined by host response to DNA damage than by DMA damage itself. Citrulline depletion because of afunctional enterocytes could be responsible for NO depletion during cytotoxic therapy. Restoring NO production during cytotoxic therapy could have a beneficial effect on mucositis development. Citrulline seems a more promising NO donor than glutamine or arginine during cytotoxic therapy, although clinical studies in mucositis patients are currently lacking.

SUMMARY

Glutamine, arginine and citrulline show in-vitro beneficial effects on inflammatory processes involved in mucositis. Translation to the clinic is difficult as demonstrated with use of glutamine and arginine. Citrulline, being the most potent NO donor with excellent oral bio-availability, is very promising as treatment choice for mucositis and its use deserves to be investigated in clinical trials with mucositis patients.

Nrf2 as a potential target for Parkinson's disease therapy

Parkinson's disease (PD) is a complex neurodegenerative disorder featuring both motor and nonmotor symptoms associated with a progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Conventionally, PD treatment options have focused on dopamine replacement and provide only symptomatic relief. However, disease-modifying therapies are still unavailable. Mechanistically, genetic and environmental factors can produce oxidative stress which has been implicated as a core contributor to the initiation and progression of PD through the degeneration of dopaminergic neurons. Importantly, nuclear factor erythroid 2-related factor 2 (Nrf2) is essential for maintaining redox homeostasis by binding to the antioxidant response element which exists in the promoter regions of most genes coding for antioxidant enzymes. Furthermore, protein kinase C, mitogen-activated protein kinases, and phosphotidylinositol 3-kinase have been implicated in the regulation of Nrf2 activity during PD. Here, we review the evidence supporting the regulation of Nrf2 through Keap1-dependent and Keap1-independent mechanisms. We also address that targeting Nrf2 may provide a therapeutic option to mitigate oxidative stress-associated PD. Finally, we discuss currently known classes of small molecule activators of Nrf2, including Nrf2-activating compounds in PD.

Brain Damage and Patterns of Neurovascular Disorder after Ionizing Irradiation. Complications in Radiotherapy and Radiation Combined Injury

Exposure to ionizing radiation, mechanical trauma, toxic chemicals or infections, or combinations thereof (i.e., combined injury) can induce organic injury to brain tissues, the structural disarrangement of interactive networks of neurovascular and glial cells, as well as on arrays of the paracrine and systemic destruction. This leads to subsequent decline in cognitive capacity and decompensation of mental health. There is an ongoing need for improvement in mitigating and treating radiation- or combined injury-induced brain injury. Cranial irradiation per se can cause a multifactorial encephalopathy that occurs in a radiation dose- and time-dependent manner due to differences in radiosensitivity among the various constituents of brain parenchyma and vasculature. Of particular concern are the radiosensitivity and inflammation susceptibility of: 1. the neurogenic and oligodendrogenic niches in the subependymal and hippocampal domains; and 2. the microvascular endothelium. Thus, cranial or total-body irradiation can cause a plethora of biochemical and cellular disorders in brain tissues, including: 1. decline in neurogenesis and oligodendrogenesis; 2. impairment of the blood-brain barrier; and 3. ablation of vascular capillary. These changes, along with cerebrovascular inflammation, underlie different stages of encephalopathy, from the early protracted stage to the late delayed stage. It is evident that ionizing radiation combined with other traumatic insults such as penetrating wound, burn, blast, systemic infection and chemotherapy, among others, can exacerbate the radiation sequelae (and vice versa) with increasing severity of neurogenic and microvascular patterns of radiation brain damage.