Functional Role of p53 in the Regulation of Chemical-Induced Oxidative Stress

Mechanisms of mitophagy and oxidative stress in cerebral ischemia-reperfusion, vascular dementia, and Alzheimer's disease

Neurological diseases have consistently represented a significant challenge in both clinical treatment and scientific research. As research has progressed, the significance of mitochondria in the pathogenesis and progression of neurological diseases has become increasingly prominent. Mitochondria serve not only as a source of energy, but also as regulators of cellular growth and death. Both oxidative stress and mitophagy are intimately associated with mitochondria, and there is mounting evidence that mitophagy and oxidative stress exert a pivotal regulatory influence on the pathogenesis of neurological diseases. In recent years, there has been a notable rise in the prevalence of cerebral ischemia/reperfusion injury (CI/RI), vascular dementia (VaD), and Alzheimer's disease (AD), which collectively represent a significant public health concern. Reduced levels of mitophagy have been observed in CI/RI, VaD and AD. The improvement of associated pathology has been demonstrated through the increase of mitophagy levels. CI/RI results in cerebral tissue ischemia and hypoxia, which causes oxidative stress, disruption of the blood-brain barrier (BBB) and damage to the cerebral vasculature. The BBB disruption and cerebral vascular injury may induce or exacerbate VaD to some extent. In addition, inadequate cerebral perfusion due to vascular injury or altered function may exacerbate the accumulation of amyloid β (Aβ) thereby contributing to or exacerbating AD pathology. Intravenous tissue plasminogen activator (tPA; alteplase) and endovascular thrombectomy are effective treatments for stroke. However, there is a narrow window of opportunity for the administration of tPA and thrombectomy, which results in a markedly elevated incidence of disability among patients with CI/RI. It is regrettable that there are currently no there are still no specific drugs for VaD and AD. Despite the availability of the U.S. Food and Drug Administration (FDA)-approved clinical first-line drugs for AD, including memantine, donepezil hydrochloride, and galantamine, these agents do not fundamentally block the pathological process of AD. In this paper, we undertake a review of the mechanisms of mitophagy and oxidative stress in neurological disorders, a summary of the clinical trials conducted in recent years, and a proposal for a new strategy for targeted treatment of neurological disorders based on both mitophagy and oxidative stress.

Implications of p53 in mitochondrial dysfunction and Parkinson's disease

Purpose: To study the underlying molecular mechanisms of p53 in the mitochondrial dysfunction and the pathogenesis of Parkinson's disease (PD), and provide a potential therapeutic target for PD treatment.

Methods: We review the contributions of p53 to mitochondrial changes leading to apoptosis and the subsequent degeneration of dopaminergic neurons in PD.

Results: P53 is a multifunctional protein implicated in the regulation of diverse cellular processes via transcription-dependent and transcription-independent mechanisms. Mitochondria are vital subcellular organelles for that maintain cellular function, and mitochondrial defect and impairment are primary causes of dopaminergic neuron degeneration in PD. Increasing evidence has revealed that mitochondrial dysfunction-associated dopaminergic neuron degeneration is tightly regulated by p53 in PD pathogenesis. Neurodegenerative stress triggers p53 activation, which induces mitochondrial changes, including transmembrane permeability, reactive oxygen species production, Ca2+ overload, electron transport chain defects and other dynamic alterations, and these changes contribute to neurodegeneration and are linked closely with PD occurrence and development. P53 inhibition has been shown to attenuate mitochondrial dysfunction and protect dopaminergic neurons from degeneration under conditions of neurodegenerative stress.

Conclusions: p53 appears to be a potential target for neuroprotective therapy of PD.

Integrating gene expression and splicing dynamics across dose-response oxidative modulators

Toxicological risk assessment increasingly utilizes transcriptomics to derive point of departure (POD) and modes of action (MOA) for chemicals. One essential biological process that allows a single gene to generate several different RNA isoforms is called alternative splicing. To comprehensively assess the role of splicing dysregulation in toxicological evaluation and elucidate its potential as a complementary endpoint, we performed RNA-seq on A549 cells treated with five oxidative stress modulators across a wide dose range. Differential gene expression (DGE) showed limited pathway enrichment except at high concentrations. However, alternative splicing analysis revealed variable intron retention events affecting diverse pathways for all chemicals in the absence of significant expression changes. For instance, diazinon elicited negligible gene expression changes but progressive increase in the number of intron retention events, suggesting splicing alterations precede expression responses. Benchmark dose modeling of intron retention data highlighted relevant pathways overlooked by expression analysis. Systematic integration of splicing datasets should be a useful addition to the toxicogenomic toolkit. Combining both modalities paint a more complete picture of transcriptomic dose-responses. Overall, evaluating intron retention dynamics afforded by toxicogenomics may provide biomarkers that can enhance chemical risk assessment and regulatory decision making. This work highlights splicing-aware toxicogenomics as a possible additional tool for examining cellular responses.

Sirtuins in intervertebral disc degeneration: current understanding

BACKGROUND

Intervertebral disc degeneration (IVDD) is one of the etiologic factors of degenerative spinal diseases, which can lead to a variety of pathological spinal conditions such as disc herniation, spinal stenosis, and scoliosis. IVDD is a leading cause of lower back pain, the prevalence of which increases with age. Recently, Sirtuins/SIRTs and their related activators have received attention for their activity in the treatment of IVDD. In this paper, a comprehensive systematic review of the literature on the role of SIRTs and their activators on IVDD in recent years is presented. The molecular pathways involved in the regulation of IVDD by SIRTs are summarized, and the effects of SIRTs on senescence, inflammatory responses, oxidative stress, and mitochondrial dysfunction in myeloid cells are discussed with a view to suggesting possible solutions for the current treatment of IVDD.

PURPOSE

This paper focuses on the molecular mechanisms by which SIRTs and their activators act on IVDD.

METHODS

A literature search was conducted in Pubmed and Web of Science databases over a 13-year period from 2011 to 2024 for the terms "SIRT", "Sirtuin", "IVDD", "IDD", "IVD", "NP", "Intervertebral disc degeneration", "Intervertebral disc" and "Nucleus pulposus".

RESULTS

According to the results, SIRTs and a large number of activators showed positive effects against IVDD.SIRTs modulate autophagy, myeloid apoptosis, oxidative stress and extracellular matrix degradation. In addition, they attenuate inflammatory factor-induced disc damage and maintain homeostasis during disc degeneration. Several clinical studies have reported the protective effects of some SIRTs activators (e.g., resveratrol, melatonin, honokiol, and 1,4-dihydropyridine) against IVDD.

CONCLUSION

The fact that SIRTs and their activators play a hundred different roles in IVDD helps to better understand their potential to develop further treatments for IVDD.

NOVELTY

This review summarizes current information on the mechanisms of action of SIRTs in IVDD and the challenges and limitations of translating their basic research into therapy.

The Prospective Effect of Green Tea versus Pomegranate Peels Extracts on Submandibular Salivary Glands of Albino Rats after Methotrexate Administration (Histological and Immunohistochemical Study)

Background

There is curiosity in the use of substances that can stop cell damage. Antioxidants are substances that can prevent free radicals from damaging cells, and they can be used to treat and avoid a wide variety of illnesses.

Objectives

The current investigation set out to evaluate the histological changes brought on by a single high dose of methotrexate in the submandibular glands of rats treated with green tea and pomegranate peel extract, both are well-known as antioxidants.

Materials and Methods

Forty-eight healthy Albino rats were used in the current study. Animals were divided into six groups. Group 1: Vehicle group which is control group, Group 2: methotrexate treated group, Group 3: green tea control group, Group 4: pomegranate peel extract control group, Group 5: green tea + methotrexate group, and Group 6: pomegranate peel extract + methotrexate group. Rats of all groups were left 1 week after the end of the treatment. Cervical dislocation was used to kill all of the rats. Samples were gained from the rats' submandibular salivary glands of different groups for histological and immunohistochemical evaluation.

Results

Green tea + methotrexate group showed improvement in the histological picture of the submandibular salivary gland compared to methotrexate group and the pomegranate peel extract + methotrexate group.

Conclusion

The antioxidant activity of green tea is more potent than that of pomegranate peels extract in blocking methotrexate that induced cytotoxicity in the submandibular salivary glands of rats. As a result, it can be administered to people undergoing cancer treatment as a safeguard for their salivary glands.

Emerging role and therapeutic implications of p53 in intervertebral disc degeneration

Lower back pain (LBP) is a common degenerative musculoskeletal disease that imposes a huge economic burden on both individuals and society. With the aggravation of social aging, the incidence of LBP has increased globally. Intervertebral disc degeneration (IDD) is the primary cause of LBP. Currently, IDD treatment strategies include physiotherapy, medication, and surgery; however, none can address the root cause by ending the degeneration of intervertebral discs (IVDs). However, in recent years, targeted therapy based on specific molecules has brought hope for treating IDD. The tumor suppressor gene p53 produces a transcription factor that regulates cell metabolism and survival. Recently, p53 was shown to play an important role in maintaining IVD microenvironment homeostasis by regulating IVD cell senescence, apoptosis, and metabolism by activating downstream target genes. This study reviews research progress regarding the potential role of p53 in IDD and discusses the challenges of targeting p53 in the treatment of IDD. This review will help to elucidate the pathogenesis of IDD and provide insights for the future development of precision treatments.

Heat stress suppresses MnSOD expression via p53-Sp1 interaction and induces oxidative stress damage in endothelial cells: Protective effects of MitoQ10 and Pifithrin-α

Aim

To investigate the mechanism of p53-mediated suppression of heat stress-induced oxidative stress damage by manganese superoxide dismutase (MnSOD) in endothelial cells (ECs).

Methods

Primary ECs isolated from mouse aortas were used to examine the effects of heat stress on vascular ECs viability and apoptosis. We measured MnSOD expression, reactive oxygen species (ROS) production, p53 expression, viability, and apoptosis of heat stress-induced ECs. We also tested the protective effects of MitoQ10, a mitochondrial-targeted antioxidant, and Pifithrin-α, a p53 inhibitor, in ECs from a mouse model of heat stroke.

Results

Heat stress increased cellular apoptosis, ROS production, and p53 expression, while reducing cellular viability and MnSOD expression in ECs. We also showed that the suppression of MnSOD expression by heat stress in ECs was mediated by interactions between p53 and Sp1. Furthermore, MitoQ10 and Pifithrin-α alleviated heat stress-induced oxidative stress and apoptosis in ECs.

Conclusion

Our results revealed that p53-mediated MnSOD downregulation is a key mechanism for heat stress-induced oxidative stress damage in ECs and indicated that MitoQ10 and Pifithrin-α could be potential therapeutic agents for heat stroke.

Methylomic, proteomic, and metabolomic correlates of traffic-related air pollution: A systematic review, pathway analysis, and network analysis relating traffic-related air pollution to subclinical and clinical cardiorespiratory outcomes

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease, and highlight contemporary challenges and opportunities associated with such efforts.

Premature ovarian insufficiency: a review on the role of oxidative stress and the application of antioxidants

Normal levels of reactive oxygen species (ROS) play an important role in regulating follicular growth, angiogenesis and sex hormone synthesis in ovarian tissue. When the balance between ROS and antioxidants is disrupted, however, it can cause serious consequences of oxidative stress (OS), and the quantity and quality of oocytes will decline. Therefore, this review discusses the interrelationship between OS and premature ovarian insufficiency (POI), the potential mechanisms and the methods by which antioxidants can improve POI through controlling the level of OS. We found that OS can mediate changes in genetic materials, signal pathways, transcription factors and ovarian microenvironment, resulting in abnormal apoptosis of ovarian granulosa cells (GCs) and abnormal meiosis as well as decreased mitochondrial Deoxyribonucleic Acid(mtDNA) and other changes, thus accelerating the process of ovarian aging. However, antioxidants, mesenchymal stem cells (MSCs), biological enzymes and other antioxidants can delay the disease process of POI by reducing the ROS level in vivo.

Sirtuin family in autoimmune diseases

In recent years, epigenetic modifications have been widely researched. As humans age, environmental and genetic factors may drive inflammation and immune responses by influencing the epigenome, which can lead to abnormal autoimmune responses in the body. Currently, an increasing number of studies have emphasized the important role of epigenetic modification in the progression of autoimmune diseases. Sirtuins (SIRTs) are class III nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases and SIRT-mediated deacetylation is an important epigenetic alteration. The SIRT family comprises seven protein members (namely, SIRT1-7). While the catalytic core domain contains amino acid residues that have remained stable throughout the entire evolutionary process, the N- and C-terminal regions are structurally divergent and contribute to differences in subcellular localization, enzymatic activity and substrate specificity. SIRT1 and SIRT2 are localized in the nucleus and cytoplasm. SIRT3, SIRT4, and SIRT5 are mitochondrial, and SIRT6 and SIRT7 are predominantly found in the nucleus. SIRTs are key regulators of various physiological processes such as cellular differentiation, apoptosis, metabolism, ageing, immune response, oxidative stress, and mitochondrial function. We discuss the association between SIRTs and common autoimmune diseases to facilitate the development of more effective therapeutic strategies.

Investigation of the efficacy of diosmin against organ damage caused by bendiocarb in male Wistar albino rats

Bendiocarb is a carbamate insecticide, which is used more in indoor areas, especially against scorpions, spiders, flies, mosquitoes and cockroaches. Diosmin is an antioxidant flavonoid found mostly in citrus fruits. In this study, the efficacy of diosmin against the adverse effects of bendiocarb was investigated in rats. For this purpose, 60, 2-3 month-old male Wistar albino rats, weighing 150-200 g, were used. The animals were assigned to six groups, one of which was maintained for control purposes and five of which were trial groups. The control rats received only corn oil, which was used as a vehicle for diosmin administration in the trial groups. Groups 2, 3, 4, 5 and 6 were administered with 10 mg/kg.bw bendiocarb, 10 mg/kg.bw diosmin, 20 mg/kg.bw diosmin, 2 mg/kg.bw bendiocarb plus 10 mg/kg.bw diosmin, and 2 mg/kg.bw bendiocarb plus 20 mg/kg.bw diosmin, respectively, using an oral catheter, for 28 days. At the end of the study period, blood and organ (liver, kidneys, brain, testes, heart and lungs) samples were collected. Body weight and organ weights were determined. Compared to the control group, in the group given bendiocarb alone, firstly, body weight and liver, lung and testicular weights decreased. Secondly, tissue/plasma malondialdehyde (MDA) and nitric oxide (NO) levels increased, and glutathione (GSH) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) (except for lung tissue), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G6PD) activities decreased in all tissues and erythrocytes. Thirdly, catalase (CAT) activity decreased in erythrocytes and the kidney, brain, heart and lung tissues and increased in the liver and testes. Fourthly, while GST activity decreased in the kidneys, testes, lung and erythrocytes, an increase was observed in the liver and heart tissues. Fifthly, while serum triglyceride levels and lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and pseudo-cholinesterase (PchE) activities decreased, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and blood urea nitrogen (BUN), creatinine and uric acid levels increased. Lastly, liver caspase 3, caspase 9 and p53 expression levels significantly increased. When compared to the control group, the groups treated with diosmin alone showed no significant difference for the parameters investigated. On the other hand, it was observed that the values of the groups treated with a combination of bendiocarb and diosmin were closer to the values of the control group. In conclusion, while exposure to bendiocarb at a dose of 2 mg/kg.bw for 28 days caused oxidative stress/organ damage, diosmin administration at doses of 10 and 20 mg/kg.bw reduced this damage. This demonstrated that diosmin has pharmaceutical benefits, when used for supportive treatment as well as radical treatment, against the potential adverse effects of bendiocarb.

The Association of Increased Oxidative Stress and Tumor Biomarkers Related to Polyaromatic Hydrocarbons Exposure for Different Occupational Workers in Makkah, Saudi Arabia

INTRODUCTION

Exposure to occupational polyaromatic hydrocarbons (PAHs) is correlated with several adverse effects on human health, including bladder, lung, and skin cancer. The correlation between PAH exposure and oxidative stress and tumor markers needs to be further explored. Therefore, we conducted this study to examine the effect of acute exposure to PAHs on oxidative stress and tumor marker levels in occupational workers during the Hajj season in Makkah.

METHODS

We conducted a cross-sectional study of 105 workers during Hajj; 60 workers were employed in the open air for ≥eight hours/day, exposed them to high levels of considerable traffic and huge crowds, and 45 workers served as our control group who were unexposed and working in a rural area. Using high-performance liquid chromatography, we analyzed participants' urinary 1-hydroxypyrene to determine PAH levels. Oxidative stress markers malondialdehyde (MDA), glutathione S-transferase (GST), and lactate dehydrogenase (LDH) were analyzed in serum using a spectrophotometer. The serum p53 and p21 proteins were analyzed using an enzyme-linked immunosorbent assay. We used IBM SPSS Statistics for Windows, Version 21.0 (IBM Corp., Armonk, NY, USA) to calculate multivariate logistic regression analysis for oxidative stress and tumor markers such as age, working period, and smoking status risk factors. Additionally, we evaluated associations between oxidative stress and tumor markers.

RESULTS

The mean levels of MDA, GST, and LDH were significantly elevated in exposed workers compared to the control group (p<.001). Also, p53 and p21 protein levels were significantly higher in the occupationally exposed group than in the unexposed control group (p<0.05). No significant correlation between age and increased levels of p53 and p21 was found.

CONCLUSIONS

 In our study, PAH exposure is significantly correlated with higher levels of oxidative stress and tumor marker levels in occupational workers. The evaluation of oxidative stress and tumor marker indicators can efficiently identify workers at high risk of PAH exposure and may assist in preventing future health concerns. More biomarkers should be included in other longitudinal studies to address exposure related to different health risks among workers, especially cancer risk. More prospective studies are required to validate diagnostic utilities and efficiencies of different biomarker combinations.

Association of p53 with Neurodegeneration in Parkinson's Disease

p53 is a vital transcriptional protein implicated in regulating diverse cellular processes, including cell cycle arrest, DNA repair, mitochondrial metabolism, redox homeostasis, autophagy, senescence, and apoptosis. Recent studies have revealed that p53 levels and activity are substantially increased in affected neurons in cellular and animal models of Parkinson's disease (PD) as well as in the brains of PD patients. p53 activation in response to neurodegenerative stress is closely associated with the degeneration of dopaminergic neurons accompanied by mitochondrial dysfunction, reactive oxygen species (ROS) production, abnormal protein aggregation, and impairment of autophagy, and these pathogenic events have been implicated in the pathogenesis of PD. Pathogenic p53 integrates diverse cellular stresses and activate these downstream events to induce the degeneration of dopaminergic neurons; thus, it plays a crucial role in the pathogenesis of PD and appears to be a potential target for the treatment of the disease. We reviewed the current knowledge concerning p53-dependent neurodegeneration to better understand the underlying mechanisms and provide possible strategies for PD treatment by targeting p53.

Genome-Wide RNAi Screening Identifies Novel Pathways/Genes Involved in Oxidative Stress and Repurposable Drugs to Preserve Cystic Fibrosis Airway Epithelial Cell Integrity

Recurrent infection-inflammation cycles in cystic fibrosis (CF) patients generate a highly oxidative environment, leading to progressive destruction of the airway epithelia. The identification of novel modifier genes involved in oxidative stress susceptibility in the CF airways might contribute to devise new therapeutic approaches. We performed an unbiased genome-wide RNAi screen using a randomized siRNA library to identify oxidative stress modulators in CF airway epithelial cells. We monitored changes in cell viability after a lethal dose of hydrogen peroxide. Local similarity and protein-protein interaction network analyses uncovered siRNA target genes/pathways involved in oxidative stress. Further mining against public drug databases allowed identifying and validating commercially available drugs conferring oxidative stress resistance. Accordingly, a catalog of 167 siRNAs able to confer oxidative stress resistance in CF submucosal gland cells targeted 444 host genes and multiple circuitries involved in oxidative stress. The most significant processes were related to alternative splicing and cell communication, motility, and remodeling (impacting cilia structure/function, and cell guidance complexes). Other relevant pathways included DNA repair and PI3K/AKT/mTOR signaling. The mTOR inhibitor everolimus, the α1-adrenergic receptor antagonist doxazosin, and the Syk inhibitor fostamatinib significantly increased the viability of CF submucosal gland cells under strong oxidative stress pressure. Thus, novel therapeutic strategies to preserve airway cell integrity from the harsh oxidative milieu of CF airways could stem from a deep understanding of the complex consequences of oxidative stress at the molecular level, followed by a rational repurposing of existing "protective" drugs. This approach could also prove useful to other respiratory pathologies.

Reactive oxygen species may influence on the crossroads of stemness, senescence, and carcinogenesis in a cell via the roles of APRO family proteins

Excessive reactive oxygen species (ROS) may cause oxidative stress which is involved in aging and in the pathogenesis of various human diseases. Whereas unregulated levels of the ROS may be harmful, regulated basal level of ROS are even necessary to support cellular functions as a second messenger for homeostasis under physiological conditions. Therefore, redox medicine could develop as a new therapeutic concept for human health-benefits. Here, we introduce the involvement of ROS on the crossroads of stemness, senescence, and carcinogenesis in a stem cell and cancer cell biology. Amazingly, the anti-proliferative (APRO) family anti-proliferative proteins characterized by immediate early growth responsive genes may also be involved in the crossroads machinery. The biological functions of APRO proteins (APROs) seem to be quite intricate, however, which might be a key modulator of microRNAs (miRNAs). Given the crucial roles of ROS and APROs for pathophysiological functions, upcoming novel therapeutics should include vigilant modulation of the redox state. Next generation of medicine including regenerative medicine and/or cancer therapy will likely comprise strategies for altering the redox environment with the APROs via the modulation of miRNAs as well as with the regulation of ROS of cells in a sustainable manner.

Sirt6 protects cardiomyocytes against doxorubicin-induced cardiotoxicity by inhibiting P53/Fas-dependent cell death and augmenting endogenous antioxidant defense mechanisms

Sirt6, a class III NAD⁺-dependent deacetylase of the sirtuin family, is a highly specific H3 deacetylase and plays important roles in regulating cellular growth and death. The induction of oxidative stress and death is the critical mechanism involved in cardiomyocyte injury and cardiac dysfunction in doxorubicin-induced cardiotoxicity, but the regulatory role of Sirt6 in the fate of DOX-impaired cardiomyocytes is poorly understood. In the present study, we exposed Sirt6 heterozygous (Sirt6^+/-) mice and their littermates as well as cultured neonatal rat cardiomyocytes to DOX, then investigated the role of Sirt6 in mitigating oxidative stress and cardiac injury in the DOX-treated myocardium. Sirt6 partial knockout or silencing worsened cardiac damage, remodeling, and oxidative stress injury in mice or cultured cardiomyocytes with DOX challenge. Cardiomyocytes infected with adenoviral constructs encoding Sirt6 showed reversal of this DOX-induced damage. Intriguingly, Sirt6 reduced oxidative stress injury by upregulating endogenous antioxidant levels, interacted with oxidative stress-stirred p53, and acted as a co-repressor of p53 in nuclei. Sirt6 was recruited by p53 to the promoter regions of the target genes Fas and FasL and further suppressed p53 transcription activity by reducing histone acetylation. Sirt6 inhibited Fas/FasL signaling and attenuated both Fas-FADD-caspase-8 apoptotic and Fas-RIP3 necrotic pathways. These results indicate that Sirt6 protects the heart against DOX-induced cardiotoxicity by upregulating endogenous antioxidants, as well as suppressing oxidative stress and cell death signaling pathways dependent on ROS-stirred p53 transcriptional activation, thus reducing Fas-FasL-mediated apoptosis and necrosis. •Sirt6 is significantly decreased in DOX-insulted mouse hearts and cardiomyocytes. •Sirt6 attenuates DOX-induced cardiac atrophy, dysfunction and oxidative stress. • Sirt6 reduces oxidative stress injury by upregulating endogenous antioxidants. • Sirt6 interacts with p53 as a co-repressor to suppress p53 transcriptional regulation and inhibits Fas-FasL-mediated apoptosis and necrosis downstream of p53.

Insights into the Role of Oxidative Stress in Ovarian Cancer

Oxidative stress (OS) arises when the body is subjected to harmful endogenous or exogenous factors that overwhelm the antioxidant system. There is increasing evidence that OS is involved in a number of diseases, including ovarian cancer (OC). OC is the most lethal gynecological malignancy, and risk factors include genetic factors, age, infertility, nulliparity, microbial infections, obesity, smoking, etc. OS can promote the proliferation, metastasis, and therapy resistance of OC, while high levels of OS have cytotoxic effects and induce apoptosis in OC cells. This review focuses on the relationship between OS and the development of OC from four aspects: genetic alterations, signaling pathways, transcription factors, and the tumor microenvironment. Furthermore, strategies to target aberrant OS in OC are summarized and discussed, with a view to providing new ideas for clinical treatment.

Impact of Reactive Oxygen and Nitrogen Species Produced by Plasma on Mdm2-p53 Complex

The study of protein–protein interactions is of great interest. Several early studies focused on the murine double minute 2 (Mdm2)–tumor suppressor protein p53 interactions. However, the effect of plasma treatment on Mdm2 and p53 is still absent from the literature. This study investigated the structural changes in Mdm2, p53, and the Mdm2–p53 complex before and after possible plasma oxidation through molecular dynamic (MD) simulations. MD calculation revealed that the oxidized Mdm2 bounded or unbounded showed high flexibility that might increase the availability of tumor suppressor protein p53 in plasma-treated cells. This study provides insight into Mdm2 and p53 for a better understanding of plasma oncology.

USP15 participates in DBP-induced testicular oxidative stress injury through regulating the Keap1/Nrf2 signaling pathway

Di-n-butylphthalate (DBP) has been listed as an environmental priority pollutant in China due to its distinct biotoxicity. Epidemiological studies have shown that exposure to DBP is closely related to a series of congenital and acquired defects in the male reproductive system. The oxidative stress injury caused by DBP plays an important role in these defects. Previous studies have demonstrated that the Keap1/Nrf2 antioxidative pathway plays a protective role in DBP-induced oxidative stress injury. However, the further molecular regulation mechanism of the activation of Nrf2 pathway remains unclear. Here, we demonstrate that DBP caused testicular oxidative stress injury and Nrf2 pathway was activated in response to the injury in vivo and in vitro. Moreover, we validated that reduced level of USP15 attenuates DBP-induced oxidative stress injury through restraining the ubiquitylation and degradation of Nrf2. Notably, USP15 is confirmed as a target of miR-135b-5p and miR-135b-5p mediated inhibition of USP15 is involved in the DBP-induced oxidative stress injury. Collectively, these findings indicated that decreased level of USP15 functions a significant protective effect on the oxidative stress injury of testis caused by DBP via regulating the Keap1/Nrf2 signaling pathway.

Vitamin E TPGS 1000 Induces Apoptosis in the K562 Cell Line: Implications for Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is a hematologic malignancy derived from the myeloid lineage molecularly characterized by t(9;22)(q34;q11) resulting in BCR-ABL1 gene fusion, which is known as Philadelphia (Ph) chromosome. Although tyrosine kinase inhibitors (TKIs) have restored and maintained the quality of life of patients with CML, an important minority of patients become resistant to first-and-second-generation TKIs and require an alternative treatment. The K562 cell (Ph+, p53-/-) line was treated with Vit E TPGS 1000 (20-80 μM) only or with other products of interest (e.g., antioxidant N-acetylcysteine (NAC), specific JNK and caspase-3 inhibitor SP600125, and NSCSI, respectively) for 24 h at 37°C. Cells were analyzed by fluorescence microscopy (FM), flow cytometry (FC), and Western blotting (WB) techniques. We show that TPGS induces apoptosis in K562 cells through H₂O₂ signaling mechanism comprising the activation of a minimal molecular cascade: the kinase JNK>the transcription factor c-JUN>the activation of BCL-only BH3 proapoptotic protein PUMA>loss of mitochondrial membrane potential (ΔΨ _m)>activation of caspase-3>chromatin condensation>fragmentation of DNA. Additionally, TPGS oxidizes the stress sensor protein DJ-1-Cys106-SH into DJ-1-Cys106-SO₃ and arrested the cell cycle in the S phase. Remarkably, NAC, SP600125, and NSCSI blocked TPGS-induced OS and apoptosis in K562. Since TPGS is safe in mice and humans, it is especially promising for preclinical and clinical CML leukemia research. Our findings support the view that oxidation therapy offers an important opportunity to eliminate CML.

SLC38A10 Transporter Plays a Role in Cell Survival Under Oxidative Stress and Glutamate Toxicity

Solute carrier (SLC) transporters regulate amino acids, glucose, ions, and metabolites that flow across cell membranes. In the brain, SLCs are the key regulators of neurotransmission, in particular, the glutamate/GABA-glutamine (GGG) cycle. Genetic mutations in SLCs are associated with various neurodevelopmental and neurodegenerative diseases. In this study, we have investigated the role of SLC38A10 under acute oxidative and glutamate stress in mouse primary cortical cells from SLC38A10 knockout (KO) mice. The ER/golgi localized transporter, SLC38A10, transports glutamate, glutamine, and alanine in brain cells, and the aim of this study was to determine the possible effects of removal of SLC38A10 in primary cortical cells under glutamate and oxidative challenges. Primary cortical neuronal cultures of wild-type (WT) cell and SLC38A10 KO mice were subjected to different concentrations of glutamate and hydrogen peroxide. There was no morphological change observed between KO and WT cortical neurons in culture. Interestingly, KO cells showed significantly lower cell viability and higher cell death compared to WT cells under both glutamate and hydrogen peroxide exposure. Further, we evaluated the possible role of p53 in neuronal cell apoptosis in KO cells. We found decreased intracellular p53 protein levels under glutamate and hydrogen peroxide treatment in KO cortical cells. In contrast, caspase 3/7 activity remains unaltered under all conditions. These results demonstrate an indirect relationship between the expression of SLC38A10 and p53 and a role in the cell defense mechanism against neurotoxicity.

p53: A Key Protein That Regulates Pulmonary Fibrosis

Pulmonary fibrosis is a progressively aggravating lethal disease that is a serious public health concern. Although the incidence of this disease is increasing, there is a lack of effective therapies. In recent years, the pathogenesis of pulmonary fibrosis has become a research hotspot. p53 is a tumor suppressor gene with crucial roles in cell cycle, apoptosis, tumorigenesis, and malignant transformation. Previous studies on p53 have predominantly focused on its role in neoplastic disease. Following in-depth investigation, several studies have linked it to pulmonary fibrosis. This review covers the association between p53 and pulmonary fibrosis, with the aim of providing novel ideas to improve the clinical diagnosis, treatment, and prognosis of pulmonary fibrosis.

Cyclosporin A protects JEG-3 cells against oxidative stress-induced apoptosis by inhibiting the p53 and JNK/p38 signaling pathways

BACKGROUND

Trophoblast cells are required for the establishment of pregnancy and fetal development. Apoptosis is an essential feature for trophoblast invasion. Uncontrolled trophoblast apoptosis is related to some complicate pregnancies. Oxidative stress (OS) is an important inducer of trophoblast apoptosis. Cyclosporin A (CsA) has been shown to promote the activity of trophoblast cells and reduce OS-induced oxidative injury. We investigated the role and mechanism of CsA in oxidative stress-induced trophoblast cell apoptosis.

METHODS

JEG-3 cells were cocultured with H₂O₂ and CsA. Cell viability and morphology were measured by MTT assay and DAPI staining. Cell apoptosis was tested with annexin V/PI staining. The expression of Bcl-2-associated X protein (Bax), B-cell lymphoma/leukemia-2 (Bcl-2), cleaved poly (ADP-ribose) polymerase (PARP) and pro-caspase-3 was assayed by western blotting. The protein expression and phosphorylation of p53 and mitogen-activated protein kinase (MAPK) kinases (JNK, ERK1/2 and p38) were examined by western blotting.

RESULTS

CsA increased the viability, alleviated morphological injury and reduced cell apoptosis of the H₂O₂-treated JEG-3 cells. CsA also attenuated the activation of p53, decreased the expression of Bax and cleavage of PARP, and increased the expression of Bcl-2 and pro-caspase-3 in the JEG-3 treated with H₂O₂. Furthermore, CsA reduced the activation of JNK and P38 but had no significant effect on the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in the H₂O₂-treated JEG-3 cells. Promoting the activation of JNK and p38 impaired the protective effect of CsA on OS-induced trophoblast apoptosis.

CONCLUSIONS

These results suggested that CsA protected trophoblast cells from OS-induced apoptosis via the inhibition of the p53 and JNK/p38 signaling pathways.

Aconitase 2 sensitizes MCF-7 cells to cisplatin eliciting p53-mediated apoptosis in a ROS-dependent manner

Aconitase 2 (ACO2) belongs to the tricarboxylic acid (TCA) cycle, which represents a key metabolic hub for cellular metabolism that is frequently altered in cancer for satisfying bioenergetic and biosynthetic requirements of proliferating cells. The promotion of ACO2 activity in breast cancer cell lines was shown to slow down proliferation imposing a switch from aerobic glycolysis to oxidative metabolism. The alteration of metabolic pathways in cancer also impinges on the sensitivity to chemotherapeutic interventions. In this work, we evidence that the presence of ACO2 sensitizes cells to the treatment with the genotoxic agents cisplatin (CDDP) and doxorubicin activating the apoptotic cell death mechanism. This response was driven by the accumulation of reactive oxygen species (ROS) following both ACO2 overexpression and CDDP exposure that permit the stabilization/activation of p53 in nuclear and mitochondrial compartments. Collectively, our results highlight that in ACO2 overexpressing cells the promotion of mitochondrial metabolism accounts for increased ROS production that was buffered by p53 mitochondrial recruitment and autophagy induction. However, these systems are not able to counteract the CDDP-mediated oxidative stress that becomes the Achilles heel for increasing susceptibility to apoptotic cell death.