Reactive Oxygen Species Induced p53 Activation: DNA Damage, Redox Signaling, or Both?

Navigating the redox landscape: reactive oxygen species in regulation of cell cycle

Objectives: To advance our knowledge of disease mechanisms and therapeutic options, understanding cell cycle regulation is critical. Recent research has highlighted the importance of reactive oxygen species (ROS) in cell cycle regulation. Although excessive ROS levels can lead to age-related pathologies, ROS also play an essential role in normal cellular functions. Many cell cycle regulatory proteins are affected by their redox status, but the precise mechanisms and conditions under which ROS promote or inhibit cell proliferation are not fully understood.Methods: This review presents data from the scientific literature and publicly available databases on changes in redox state during the cell cycle and their effects on key regulatory proteins.Results: We identified redox-sensitive targets within the cell cycle machinery and analysed different effects of ROS (type, concentration, duration of exposure) on cell cycle phases. For example, moderate levels of ROS can promote cell proliferation by activating signalling pathways involved in cell cycle progression, whereas excessive ROS levels can induce DNA damage and trigger cell cycle arrest or cell death.Discussion: Our findings encourage future research focused on identifying redox-sensitive targets in the cell cycle machinery, potentially leading to new treatments for diseases with dysregulated cell proliferation.

Disruption of NADPH homeostasis by total flavonoids from Adinandra nitida Merr. ex Li leaves triggers ROS-dependent p53 activation leading to apoptosis in non-small cell lung cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Adinandra nitida Merr. ex Li leaves serve as a herbal tea and hold a significant role in traditional Chinese medicine, being applied to assist in tumor treatment. Flavonoids present the primary bioactive constituents in Adinandra nitida Merr. ex Li leaves.

AIM OF THE STUDY

To explore the potential of total flavonoids from Adinandra nitida Merr. ex Li Leaves (TFAN) in inhibiting non-small cell lung cancer (NSCLC) and further elucidate the underlying mechanisms.

MATERIALS AND METHODS

Human NSCLC cell lines and normal lung cell line were employed to assess the impact of TFAN (0-160 μg/mL for 24, 28 and 72 h) on cell proliferation in vitro. Immunofluorescence (IF) staining gauged p53 expression changes in NSCLC cells under TFAN present condition (150 μg/mL for 24 h). In vivo study utilized NSCLC cell derived xenograft tumors in nude mice, administering TFAN orally (200 and 400 mg/kg) for 14 days. Immunohistochemistry assessed Cleaved Caspase 3 expression change in A549 xenograft tumors treated with TFAN (400 mg/kg for 14 days). RNA-seq and KEGG analysis identified gene expression changes and enriched processes in A549 xenograft tumors treated with TFAN. CM-H2DCFDA and metabolomics assessed ROS level and GSH/GSSG pool changes in A549 cells under TFAN present condition. Cell viability assay and IF staining assessed A549 cell proliferation and p53 expression changes under H2O2-induced oxidative stress (0-40 μM for 24 h) and TFAN present conditions. GSEA and N-Acetyl-L-cysteine (NAC) rescue (0-1 μM for 24 h) analyzed the impact of TFAN on GSH de novo synthesis. NADPH/NADP+ pool measurement and NADPH rescue (0-10 μM for 24 h) analyzed the impact of TFAN on GSH salvage synthesis. GC-FID and HPLC-MS were utilized to detect ethanol and ethyl acetate residues, and to characterize the chemical constituents in TFAN, respectively. The total flavonoid content of TFAN was determined using a 330 nm wavelength.

RESULTS

TFAN significantly inhibited A549 cells (wild-type p53) but not NCI-H1299 cells (p53-deficient), NCI-H596 cells (p53-mutant) or BEAS-2B in vitro. IF staining validated p53 genotype for the cell lines and revealed an increase in p53 expression in A549 cells after TFAN treatment. In vivo, TFAN selectively inhibited A549 xenograft tumor growth without discernible toxicity, inducing apoptosis evidenced by Cleaved Caspase 3 upregulation. RNA-seq and KEGG analysis suggested ROS biosynthesis was involved in TFAN-induced p53 activation in A549 cells. Elevated ROS level in TFAN-treated A549 cells were observed. Moreover, TFAN sensitized A549 cells to H2O2-induced oxidative stress, with higher p53 expression. Additionally, A549 cells compensated with GSH de novo synthesis under TFAN present condition, confirmed by GSEA and NAC rescue experiment. TFAN disrupted NADPH homeostasis to impair GSH salvage biosynthesis, supported by NADPH/NADP+ change and NADPH rescue experiment. The chemical constituents of TFAN, with acceptable limits for ethanol and ethyl acetate residues and a total flavonoid content of 68.87%, included Catechin, Epicatechin, Quercitroside, Camellianin A, and Apigenin.

CONCLUSION

The disruption of NADPH homeostasis by TFAN triggers ROS-dependent p53 activation that leads to apoptotic cell death, ultimately suppressing NSCLC growth. These findings offer potential therapeutic implications of Adinandra nitida Merr. ex Li leaves in combating NSCLC.

Fabrication of folic acid-conjugated pyrimidine-2(5H)-thione-encapsulated curdlan gum-PEGamine nanoparticles for folate receptor targeting breast cancer cells

In this study 5-((2-((3-methoxy benzylidene)-amino)-phenyl)-diazenyl)-4,6-diphenyl pyrimidine-2(5H)-thione was synthesized. The pharmacological applications of pyrimidine analogs are restricted due to their poor pharmacokinetic properties. As a solution, a microbial exopolysaccharide (curdlan gum) was used to synthesize folic acid-conjugated pyrimidine-2(5H)-thione-encapsulated curdlan gum-PEGamine nanoparticles (FA-Py-CG-PEGamine NPs). The results of physicochemical properties revealed that the fabricated FA-Py-CG-PEGamine NPs were between 100 and 400 nm in size with a majorly spherical shaped, crystalline nature, and the encapsulation efficiency and loading capacity were 79.04 ± 0.79 %, and 8.12 ± 0.39 % respectively. The drug release rate was significantly higher at pH 5.4 (80.14 ± 0.79 %) compared to pH 7.2. The cytotoxic potential of FA-Py-CG-PEGamine NPs against MCF-7 cells potentially reduced the number of cells after 24 h with 42.27 μg × mL-1 as IC50 value. The higher intracellular accumulation of pyrimidine-2(5H)-thione in MCF-7 cells leads to apoptosis, observed by AO/EBr staining and flow cytometry analysis. The highest pyrimidine-2(5H)-thione internalization in MCF-7 cells may be due to folate conjugated on the surface of curdlan gum nanoparticles. Further, internalized pyrimidine-2(5H)-thione increases the intracellular ROS level, leading to apoptosis and inducing the decalin in mitochondrial membrane potential. These outcomes demonstrated that the FA-Py-CG-PEGamine NPs were specificity-targeting folate receptors on the plasma membranes of MCF-7 Cells.

Prognostic value and potential regulatory relationship of miR-200c-5p in colorectal cancer

This study aimed to investigate the relationship and potential mechanisms of miR-200c-5p in colorectal cancer (CRC) progression. Differentially expressed miRNAs were screened using the TCGA database. Subsequently, univariate analysis was performed to identify CRC survival-related miRNAs. Survival and receiver operator characteristic curves were generated. The target genes of miR-200c-5p and the relevant signaling pathways or biological processes were predicted by the miRNet database and enrichment analyses. The miR-200c-5p expression was detected using quantitative reverse-transcription polymerase chain reaction, Cell Counting Kit-8, Transwell, and cell apoptosis experiments were performed to determine miR-200c-5p's impact on CRC cell viability, invasiveness, and apoptosis. Finally, we constructed a CRC mouse model with inhibited miR-200c-5p to evaluate its impact on tumors. miR-200c-5p was upregulated in CRC, implying a favorable prognosis. Gene set enrichment analysis revealed that miR-200c-5p may participate in signaling pathways such as the TGF-β signaling pathway, RIG-I-like receptor signaling pathway, renin-angiotensin system, and DNA replication. miR-200c-5p potentially targeted mRNAs, including KCNE4 and CYP1B1, exhibiting a negative correlation with their expression. Furthermore, these mRNAs may participate in biological processes like the regulation of intracellular transport, cAMP-dependent protein kinase regulatory activity, ubiquitin protein ligase binding, MHC class II protein complex binding, and regulation of apoptotic signaling pathway. Lastly, miR-200c-5p overexpression repressed the viability and invasiveness of CRC cells but promoted apoptosis. The tumor size, weight, and volume were significantly increased by inhibiting miR-200c-5p (p < 0.05). miR-200c-5p is upregulated in CRC, serving as a promising biomarker for predicting CRC prognosis.

Propolis as an autophagy modulator in relation to its roles in redox balance and inflammation regulation

Autophagy is a degradation process that is evolutionarily conserved and is essential in maintaining cellular and physiological homeostasis through lysosomal removal and elimination of damaged peptides, proteins and cellular organelles. The dysregulation of autophagy is implicated in various diseases and disorders, including cancers, infection-related, and metabolic syndrome-related diseases. Propolis has been demonstrated in various studies including many human clinical trials to have antimicrobial, antioxidant, anti-inflammatory, immune-modulator, neuro-protective, and anti-cancer. Nevertheless, the autophagy modulation properties of propolis have not been extensively studied and explored. The role of propolis and its bioactive compounds in modulating cellular autophagy is possibly due to their dual role in redox balance and inflammation. The present review attempts to discuss the activities of propolis as an autophagy modulator in biological models in relation to various diseases/disorders which has implications in the development of propolis-based nutraceuticals, functional foods, and complementary therapies.

Shengjihuayu formula ameliorates the oxidative injury in human keratinocytes via blocking JNK/c-Jun/MMPs signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The reactive oxygen species (ROS) surge in the chronic wound tissue of diabetic ulcers (DUs) aggravates the inflammatory response. The oxidative stress state during inflammation will exacerbate inflammation and cause tissue damage, resulting in prolonged wound healing. Shengjihuayu Formula (SJHYF) is a renowned Chinese medicine prescription for treating chronic wounds in diabetic ulcers. Growing clinical evidence has demonstrated that SJHYF exhibits superior therapeutic efficacy and has a favorable safety profile. However, the underlying mechanisms by which SJHYF ameliorates oxidative damage under pathological conditions of DUs remain unclear.

OBJECTIVE

To investigate the cytoprotective properties of SJHYF on hydrogen peroxide (H2O2)-induced cell damage in human HaCaT keratinocytes and to explore its potential targets and molecular pathways in treating DUs using RNA-seq.

METHODS

HaCaT cells were incubated with H2O2 for 24 h to construct an oxidative stress cell model. Cell viability and proliferation were measured using the MTT and EdU assays, respectively. Cell migration was assessed using the scratch assay, and the fluorescence intensity of ROS was measured using the DCFH-DA probe. The chemical components of SJHYF were analyzed by UPLC-Q-TOF/MS, while the therapeutic effects of SJHYF on H2O2-induced HaCaT cells were analyzed using RNA-Seq. The potential target genes were validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). At the same time, the pathway phenotype expression of SJHYF on the protection of H2O2-induced HaCaT cells was explored using Western Blot.

RESULTS

The application of SJHY at a concentration of 0.25 mg/mL promoted cell proliferation, cell migration, and reduced ROS production. In addition, SJHYF was detected to have a total of 93 active compounds, including key components such as Galloyl-beta-D-glucose, Danshensu, Procyanidin B2, Catechin, and Alkannin. The RNA-seq analysis identified several core targets namely KRT17, TGM1, JUNB, PRDX5, TXNIP, PRDX1, HSP90AA1, HSP90AB1, HSPA8, and TNF-α. Western blot revealed the presence of the JNK/c-Jun/MMPs pathway and its related transcription factors.

CONCLUSION

SJHYF displays significant protective effects on H2O2-induced oxidative cell damage in HaCaT cells via blocking the JNK/c-Jun/MMPs pathway.

Role of oxidative stress-induced ferroptosis in cancer therapy

Ferroptosis is a distinct mode of cell death, distinguishing itself from typical apoptosis by its reliance on the accumulation of iron ions and lipid peroxides. Cells manifest an imbalance between oxidative stress and antioxidant equilibrium during certain pathological contexts, such as tumours, resulting in oxidative stress. Notably, recent investigations propose that heightened intracellular reactive oxygen species (ROS) due to oxidative stress can heighten cellular susceptibility to ferroptosis inducers or expedite the onset of ferroptosis. Consequently, comprehending role of ROS in the initiation of ferroptosis has significance in elucidating disorders related to oxidative stress. Moreover, an exhaustive exploration into the mechanism and control of ferroptosis might offer novel targets for addressing specific tumour types. Within this context, our review delves into recent fundamental pathways and the molecular foundation of ferroptosis. Four classical ferroptotic molecular pathways are well characterized, namely, glutathione peroxidase 4-centred molecular pathway, nuclear factor erythroid 2-related factor 2 molecular pathway, mitochondrial molecular pathway, and mTOR-dependent autophagy pathway. Furthermore, we seek to elucidate the regulatory contributions enacted by ROS. Additionally, we provide an overview of targeted medications targeting four molecular pathways implicated in ferroptosis and their potential clinical applications. Here, we review the role of ROS and oxidative stress in ferroptosis, and we discuss opportunities to use ferroptosis as a new strategy for cancer therapy and point out the current challenges persisting within the domain of ROS-regulated anticancer drug research and development.

Comparative study of nickel oxide and nickel oxide nanoparticles on oxidative damage, apoptosis and histopathological alterations in rat lung tissues

BACKGROUND

Nickel oxide nanoparticles (NiONPs) are used as industrial photoelectric and recording materials, catalysts, and sensors. It has been increasingly used in many industrial sectors. Lungs are the important biological barrier that comes into contact with nanomaterials in the inhaled air. This study aimed to compare the effects of nickel oxide (NiO) microparticles and NiONPs on rat lung tissues in different dose administrations, such as oral, intraperitoneal, and intravenous.

METHODS

The mature male Wistar rats (n = 42) were divided into seven groups with six animals: Group I (control), Group II NiO gavage (150 mg/kg), Group III NiO intraperitoneally (20 mg/kg), Group IV NiO intravenously (1 mg/kg), Group V NiONP gavage (150 mg/kg), Group VI NiONP intraperitoneal (20 mg/kg), and Group VII NiONP intravenous (1 mg/kg) for 21 days. Oxidative stress (MDA, CAT, SOD, GPx, and GST), apoptotic marker (p53) gene expression, and histopathological changes were determined comparatively.

RESULTS

Our data showed that NiO and NiONPs caused an exposure-related increase in the incidence of alveolar/bronchiolar pathological changes, oxidative damage, and p53 gene expression in male rats. Intravenous exposure to NiONPs produces statistically (p < 0.05) more oxidative damage and histopathological changes than exposure to NİO. It also induces higher upregulation of the pro-apoptotic p53 gene.

CONCLUSION

NiO and NiONPs induce oxidative damage, histopathological alterations and p53 gene expression in rat lungs. Thus, exposure to NiO and NiONPs, especially intravenously, may indicate more toxicity and carcinogenicity.

Temporal coordination of the transcription factor response to H2O2 stress

Oxidative stress from excess H2O2 activates transcription factors that restore redox balance and repair oxidative damage. Although many transcription factors are activated by H2O2, it is unclear whether they are activated at the same H2O2 concentration, or time. Dose-dependent activation is likely as oxidative stress is not a singular state and exhibits dose-dependent outcomes including cell-cycle arrest and cell death. Here, we show that transcription factor activation is both dose-dependent and coordinated over time. Low levels of H2O2 activate p53, NRF2 and JUN. Yet under high H2O2, these transcription factors are repressed, and FOXO1, NF-κB, and NFAT1 are activated. Time-lapse imaging revealed that the order in which these two groups of transcription factors are activated depends on whether H2O2 is administered acutely by bolus addition, or continuously through the glucose oxidase enzyme. Finally, we provide evidence that 2-Cys peroxiredoxins control which group of transcription factors are activated.

Raspberry polyphenols target molecular pathways of heart failure

Approximately 650,000 new cases of heart failure (HF) are diagnosed annually with a 50% five-year mortality rate. HF is characterized by reduced left ventricular (LV) ejection fraction and hypertrophy of the LV wall. The pathophysiological remodeling of the heart is mediated by increased oxidative stress and inflammation. Raspberries are rich in polyphenols which may favorably impact enzymes involved in redox homeostasis while also targeting inflammatory signaling. Thus, the objective of this study was to investigate whether raspberry polyphenols could attenuate HF. Sprague Dawley rats consumed a 10% (w/w) raspberry diet for 7 weeks. At week 3, HF was surgically induced via coronary artery ligation. Hemodynamics and morphology of the heart were assessed. Expression of cardiac proteins involved in oxidative stress, inflammation, apoptosis, and remodeling were examined, and histological analysis was conducted. Additionally, human cardiomyocytes were treated with raspberry polyphenol extract (RBPE) followed by CoCl2 to chemically induce hypoxia. Redox status, apoptosis, and mitochondrial dysfunction were measured. Raspberries attenuated reductions in cardiac function and reduced morphological changes which coincided with reduced toll-like receptor (TLR)4 signaling. Reductions in oxidative stress, apoptosis, and remodeling occurred in vivo. Incubation of cardiomyocytes with RBPE attenuated CoCl2-induced oxidative stress and apoptosis despite pronounced hypoxia-inducible factor (HIF)-1α expression. These data indicate that consumption of raspberries can reduce the underlying molecular drivers of HF; thus, leading to the observed improvements in cardiac functional capacity and morphology. This dietary strategy may be an effective alternative strategy for treating HF. However, further investigation into alternative models of HF is warranted.

A Prognostic Activity of Glutaredoxin 1 Protein (Grx1) in Colon Cancer

Glutaredoxin 1 (Grx1) is an essential enzyme that regulates redox signal transduction and repairs protein oxidation by reversing S-glutathionylation, an oxidative modification of protein cysteine residues. Grx1 removes glutathione from proteins to restore their reduced state (protein-SH) and regulate protein-SSG levels in redox signaling networks. Thus, it can exert an influence on the development of cancer. To further investigate this problem, we performed an analysis of Grx1 expression in colon adenocarcinoma samples from the Polish population of patients with primary colon adenocarcinoma (stages I and II of colon cancer) and those with regional lymph node metastasis (stage III of colon cancer). Our study revealed a significant correlation between the expression of Grx1 protein through immunohistochemical analysis and various clinical characteristics of patients, such as histological grade, depth of invasion, angioinvasion, staging, regional lymph node invasion, and PCNA expression. It was found that almost 88% of patients with stage I had high levels of Grx1 expression, while only 1% of patients with stage III exhibited high levels of Grx1 protein expression. Furthermore, the study discovered that high levels of Grx1 expression were present in samples of colon mucosa without any pathological changes. These results were supported by in vitro analysis conducted on colorectal cancer cell lines that corresponded to stages I, II, and III of colorectal cancer, using qRT-PCR and Western blot.

Mitochondrial oxidative damage reprograms lipid metabolism of renal tubular epithelial cells in the diabetic kidney

The functional and structural changes in the proximal tubule play an important role in the occurrence and development of diabetic kidney disease (DKD). Diabetes-induced metabolic changes, including lipid metabolism reprogramming, are reported to lead to changes in the state of tubular epithelial cells (TECs), and among all the disturbances in metabolism, mitochondria serve as central regulators. Mitochondrial dysfunction, accompanied by increased production of mitochondrial reactive oxygen species (mtROS), is considered one of the primary factors causing diabetic tubular injury. Most studies have discussed how altered metabolic flux drives mitochondrial oxidative stress during DKD. In the present study, we focused on targeting mitochondrial damage as an upstream factor in metabolic abnormalities under diabetic conditions in TECs. Using SS31, a tetrapeptide that protects the mitochondrial cristae structure, we demonstrated that mitochondrial oxidative damage contributes to TEC injury and lipid peroxidation caused by lipid accumulation. Mitochondria protected using SS31 significantly reversed the decreased expression of key enzymes and regulators of fatty acid oxidation (FAO), but had no obvious effect on major glucose metabolic rate-limiting enzymes. Mitochondrial oxidative stress facilitated renal Sphingosine-1-phosphate (S1P) deposition and SS31 limited the elevated Acer1, S1pr1 and SPHK1 activity, and the decreased Spns2 expression. These data suggest a role of mitochondrial oxidative damage in unbalanced lipid metabolism, including lipid droplet (LD) formulation, lipid peroxidation, and impaired FAO and sphingolipid homeostasis in DKD. An in vitro study demonstrated that high glucose drove elevated expression of cytosolic phospholipase A2 (cPLA2), which, in turn, was responsible for the altered lipid metabolism, including LD generation and S1P accumulation, in HK-2 cells. A mitochondria-targeted antioxidant inhibited the activation of cPLA2f isoforms. Taken together, these findings identify mechanistic links between mitochondrial oxidative metabolism and reprogrammed lipid metabolism in diabetic TECs, and provide further evidence for the nephroprotective effects of SS31 via influencing metabolic pathways.

Interplay of oxidative stress, cellular communication and signaling pathways in cancer

Cancer remains a significant global public health concern, with increasing incidence and mortality rates worldwide. Oxidative stress, characterized by the production of reactive oxygen species (ROS) within cells, plays a critical role in the development of cancer by affecting genomic stability and signaling pathways within the cellular microenvironment. Elevated levels of ROS disrupt cellular homeostasis and contribute to the loss of normal cellular functions, which are associated with the initiation and progression of various types of cancer. In this review, we have focused on elucidating the downstream signaling pathways that are influenced by oxidative stress and contribute to carcinogenesis. These pathways include p53, Keap1-NRF2, RB1, p21, APC, tumor suppressor genes, and cell type transitions. Dysregulation of these pathways can lead to uncontrolled cell growth, impaired DNA repair mechanisms, and evasion of cell death, all of which are hallmark features of cancer development. Therapeutic strategies aimed at targeting oxidative stress have emerged as a critical area of investigation for molecular biologists. The objective is to limit the response time of various types of cancer, including liver, breast, prostate, ovarian, and lung cancers. By modulating the redox balance and restoring cellular homeostasis, it may be possible to mitigate the damaging effects of oxidative stress and enhance the efficacy of cancer treatments. The development of targeted therapies and interventions that specifically address the impact of oxidative stress on cancer initiation and progression holds great promise in improving patient outcomes. These approaches may include antioxidant-based treatments, redox-modulating agents, and interventions that restore normal cellular function and signaling pathways affected by oxidative stress. In summary, understanding the role of oxidative stress in carcinogenesis and targeting this process through therapeutic interventions are of utmost importance in combating various types of cancer. Further research is needed to unravel the complex mechanisms underlying oxidative stress-related pathways and to develop effective strategies that can be translated into clinical applications for the management and treatment of cancer. Video Abstract.

Malonate differentially affects cell survival and confers chemoresistance in cancer cells via the induction of p53-dependent autophagy

Metabolic network intertwines with cancerous signaling and drug responses. Malonate is a prevailing metabolite in cancer and a competitive inhibitor of succinate dehydrogenase (SDH). Recent studies showed that malonate induced reactive oxygen species (ROS)-dependent apoptosis in neuroblastoma cells, but protected cells from ischemia-reperfusion injury. We here revealed that malonate differentially regulated cell death and survival in cancer cells. While high-dose malonate triggered ROS-dependent apoptosis, the low-dose malonate induced autophagy and conferred resistance to multiple chemotherapeutic agents. Mechanistically, our results showed that malonate increased p53 stability and transcriptionally up-regulated autophagy modulator DRAM (damage-regulated autophagy modulator), thus promoting autophagy. We further proved that autophagy is required for malonate-associated chemoresistance. Collectively, our findings suggest that malonate plays a double-edge function in cancer response to stressors, and highlights a pro-cancer impact of p53-induced autophagy in response to malonate.

Dicarbonyl-Modified Low-Density Lipoproteins Are Key Inducers of LOX-1 and NOX1 Gene Expression in the Cultured Human Umbilical Vein Endotheliocytes

Expression of LOX-1 and NOX1 genes in the human umbilical vein endotheliocytes (HUVECs) cultured in the presence of low-density lipoproteins (LDL) modified with various natural dicarbonyls was investigated for the first time. It was found that among the investigated dicarbonyl-modified LDLs (malondialdehyde (MDA)-modified LDLs, glyoxal-modified LDLs, and methylglyoxal-modified LDLs), the MDA-modified LDLs caused the greatest induction of the LOX-1 and NOX1 genes, as well as of the genes of antioxidant enzymes and genes of proapoptotic factors in HUVECs. Key role of the dicarbonyl-modified LDLs in the molecular mechanisms of vascular wall damage and endothelial dysfunction is discussed.

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.

The role of reactive oxygen species in bone cell physiology and pathophysiology

Hydrogen peroxide (H2O2), superoxide anion radical (O2-•), and other forms of reactive oxygen species (ROS) are produced by the vast majority of mammalian cells and can contribute both to cellular homeostasis and dysfunction. The NADPH oxidases (NOX) enzymes and the mitochondria electron transport chain (ETC) produce most of the cellular ROS. Multiple antioxidant systems prevent the accumulation of excessive amounts of ROS which cause damage to all cellular macromolecules. Many studies have examined the contribution of ROS to different bone cell types and to skeletal physiology and pathophysiology. Here, we discuss the role of H2O2 and O2-• and their major enzymatic sources in osteoclasts and osteoblasts, the fundamentally different ways via which these cell types utilize mitochondrial derived H2O2 for differentiation and function, and the molecular mechanisms that impact and are altered by ROS in these cells. Particular emphasis is placed on evidence obtained from mouse models describing the contribution of different sources of ROS or antioxidant enzymes to bone resorption and formation. Findings from studies using pharmacological or genetically modified mouse models indicate that an increase in H2O2 and perhaps other ROS contribute to the loss of bone mass with aging and estrogen deficiency, the two most important causes of osteoporosis and increased fracture risk in humans.

[Molecular and cellular mechanisms of ageing: modern knowledge (literature review)]

Ageing (as known as eldering, senescence) is a genetically and epigenetically programmed pathophysiological process. Velocity of biological ageing is defined as balance between alteration and reparation of body structures. According to last World Health Organization (WHO) highlights ageing still stays an extremely actual scientific, social and demographic problem: in 2020 total number of people older than 60 years and older was 1 billion people; in 2030 future number may be 1,4 billion people, in 2050 - 2,1 billion people. Absence of single universal theory of aging nowadays is reason for scientifical and clinical collaboration between biologists and doctors, including endocrinologists. Designing of potentially effective newest anti-ageing strategies (such as natural/synthetic telomerase regulators, mesenchymal stem cells etc.) is of interest to scientific community. The aim of present article is a review of modern omics (genomic, proteomic, metabolomic) ageing mechanisms, potential ways of targeted prevention and treatment of age-related disease according to conception of personalized medicine. Present review is narrative, it does not lead to systematic review, meta-analysis and does not aim to commercial advertisement. Review has been provided via PubMed article that have been published since 1979 until 2022.

RICH2 decreases the mitochondrial number and affects mitochondrial localization in diffuse low-grade glioma-related epilepsy

Epilepsy, a common complication of diffuse low-grade gliomas (DLGGs; diffuse oligodendroglioma and astrocytoma collectively), severely compromises the quality of life of patients. DLGG epileptogenicity may primarily be generated by interactions between the tumor and the neocortex. Neuronal uptake of dysfunctional mitochondria from the extracellular environment can lead to abnormal neuronal discharge. Mitochondrial dysfunction is frequently observed in gliomas that can transmigrate across the plasma membranes. Here, we examined the role of the Rho GTPase-activating protein 44 (RICH2) in mitochondrial dynamics and DLGG-related epilepsy. We investigated the association between mitochondrial and RICH2 expression in human DLGG tissues using immunohistochemistry. We examined the association between RICH2 and epilepsy in nude mouse glioma models by electrophysiology. The effect of RICH2 on mitochondrial morphology and calcium motility were assessed by single cell fluorescence microscopy. Quantitative RT-PCR (qRT-PCR) and Western blot analysis were performed to characterize RICH2 induced expression changes in the genes related to mitochondrial dynamics, mitogenesis and mitochondrial function. We found that RICH2 expression was higher in oligodendroglioma than in astrocytoma and was correlated with better prognosis and higher epilepsy rate in patients. The expression of mitochondria may be associated with clinical DLGG-related epilepsy and reduced by RICH2 overexpression. And RICH2 could promote DLGG-related epilepsy in tumorigenic nude mice. RICH2 overexpression decreased calcium flow and the mitochondria released from glioma cells (SW1088 and U251) into the extracellular environment, potentially via downregulation of MFN-1/MFN-2 levels which suggests reduced mitochondrial fusion. In addition, we observed decreased mitochondrial trafficking into neurons (released from glioma cells and trafficked into neurons), which could explain the higher incidence of DLGG-related epilepsy due to reduced neuroprotection. Furthermore, RICH2 downregulated MAPK/ERK/HIF-1 pathway. In conclusion, these results suggest that RICH2 could promote epilepsy by (i) inhibiting mitochondrial fusion via MFN downregulation and Drp-1 upregulation; (ii) altering the MAPK/ERK/Hif-1 signaling axis. RICH2 may be a potential target in the treatment of DLGG-related epilepsy.

The Role of Hydrogen Sulfide in the Localization and Expression of p53 and Cell Death in the Nervous Tissue in Traumatic Brain Injury and Axotomy

Traumatic brain injury (TBI) is one of the leading causes of disability and death worldwide. It is characterized by various molecular-cellular events, with the main ones being apoptosis and damage to axons. To date, there are no clinically effective neuroprotective drugs. In this study, we examined the role of hydrogen sulfide (H2S) in the localization and expression of the key pro-apoptotic protein p53, as well as cell death in the nervous tissue in TBI and axotomy. We used a fast donor (sodium sulphide, Na2S) H2S and a classic inhibitor (aminooxyacetic acid, AOAA) of cystathionine β-synthase (CBS), which is a key enzyme in H2S synthesis. These studies were carried out on three models of neurotrauma in vertebrates and invertebrates. As a result, it was found that Na2S exhibits a pronounced neuroprotective effect that reduces the number of TUNEL-positive neurons and glial cells in TBI and apoptotic glia in axotomy. This effect could be realized through the Na2S-dependent decrease in the level of p53 in the cells of the nervous tissue of vertebrates and invertebrates, which we observed in our study. We also observed the opposite effect when using AOAA, which indicates the important role of CBS in the regulation of p53 expression and death of neurons and glial cells in TBI and axotomy.

Calcium/P53/Ninjurin 1 Signaling Mediates Plasma Membrane Rupture of Acinar Cells in Severe Acute Pancreatitis

Ninjurin 1 (NINJ1) is a double-transmembrane cell-surface protein that might mediate plasma membrane rupture (PMR) and the diffusion of inflammatory factors. PMR is a characteristic of acinar cell injury in severe acute pancreatitis (SAP). However, the involvement of NINJ1 in mediating the PMR of acinar cells in SAP is currently unclear. Our study has shown that NINJ1 is expressed in acinar cells, and the expression is significantly upregulated in sodium-taurocholate-induced SAP. The knockout of NINJ1 delays PMR in acinar cells and alleviates SAP. Moreover, we observed that NINJ1 expression is mediated by Ca2+ concentration in acinar cells. Importantly, we found that Ca2+ overload drives mitochondrial stress to upregulate the P53/NINJ1 pathway, inducing PMR in acinar cells, and amlodipine, a Ca2+ channel inhibitor, can reduce the occurrence of PMR by decreasing the concentration of Ca2+. Our results demonstrate the mechanism by which NINJ1 induces PMR in SAP acinar cells and provide a potential new target for treatment of SAP.

The role of neutrophils in chorioamnionitis

Chorioamnionitis, commonly referred to as intrauterine infection or inflammation, is pathologically defined by neutrophil infiltration and inflammation at the maternal-fetal interface. Chorioamnionitis is the common complication during late pregnancy, which lead to a series of serious consequences, such as preterm labor, preterm premature rupture of the fetal membranes, and fetal inflammatory response syndrome. During infection, a large number of neutrophils migrate to the chorio-decidua in response to chemokines. Although neutrophils, a crucial part of innate immune cells, have strong anti-inflammatory properties, over-activating them can harm the body while also eliminating pathogens. This review concentrated on the latest studies on chorioamnionitis-related consequences as well as the function and malfunction of neutrophils. The release of neutrophil extracellular traps, production of reactive oxygen species, and degranulation from neutrophils during intrauterine infection, as well as their pathological roles in complications related to chorioamnionitis, were discussed in detail, offering fresh perspectives on the treatment of chorioamnionitis.

Oxidative stress induced by Pollonein-LAAO, a new L-amino acid oxidase from Bothrops moojeni venom, prompts prostate tumor spheroid cell death and impairs the cellular invasion process in vitro

Cancer cells produce abnormal levels of reactive oxygen species (ROS) that contribute to promote their malignant phenotype. In this framework, we hypothesized that the change in ROS concentration above threshold could impair key events of prostate cancer cells (PC-3) progression. Our results demonstrated that Pollonein-LAAO, a new L-amino acid oxidase obtained from Bothrops moojeni venom, was cytotoxic to PC-3 cells in two-dimensional and in tumor spheroid assays. Pollonein-LAAO was able to increase the intracellular ROS generation that culminates in cell death from apoptosis by both intrinsic and extrinsic pathways due to the up-regulation of TP53, BAX, BAD, TNFRSF10B and CASP8. Additionally, Pollonein-LAAO reduced mitochondrial membrane potential and caused G0/G1 phase to delay, due to the up-regulation of CDKN1A and the down-regulation of the expression of CDK2 and E2F. Interestingly, Pollonein-LAAO inhibited critical steps of the cellular invasion process (migration, invasion and adhesion), due to the down-regulation of SNAI1, VIM, MMP2, ITGA2, ITGAV and ITGB3. Furthermore, the Pollonein-LAAO effects were associated with the intracellular ROS production, since the presence of catalase restored the invasiveness of PC-3 cells. In this sense, this study contributes to the potential use of Pollonein-LAAO as ROS-based agent to enhance the current understanding of cancer treatment strategies.

Simultaneous suppression of PKM2 and PHGDH elicits synergistic anti-cancer effect in NSCLC

Metabolic reprogramming is a hallmark of human cancer. Cancer cells exhibit enhanced glycolysis, which allows glycolytic intermediates to be diverted into several other biosynthetic pathways, such as serine synthesis. Here, we explored the anti-cancer effects of the pyruvate kinase (PK) M2 inhibitor PKM2-IN-1 alone or in combination with the phosphoglycerate dehydrogenase (PHGDH) inhibitor NCT-503 in human NSCLC A549 cells in vitro and in vivo. PKM2-IN-1 inhibited proliferation and induced cell cycle arrest and apoptosis, with increased glycolytic intermediate 3-phosphoglycerate (3-PG) level and PHGDH expression. The combination of PKM2-IN-1 and NCT-503 further suppressed cancer cell proliferation and induced G2/M phase arrest, accompanied by the reduction of ATP, activation of AMPK and inhibition of its downstream mTOR and p70S6K, upregulation of p53 and p21, as well as downregulation of cyclin B1 and cdc2. In addition, combined treatment triggered ROS-dependent apoptosis by affecting the intrinsic Bcl-2/caspase-3/PARP pathway. Moreover, the combination suppressed glucose transporter type 1 (GLUT1) expression. In vivo, co-administration of PKM2-IN-1 and NCT-503 significantly inhibited A549 tumor growth. Taken together, PKM2-IN-1 in combination with NCT-503 exhibited remarkable anti-cancer effects through induction of G2/M cell cycle arrest and apoptosis, in which the metabolic stress induced ATP reduction and ROS augmented DNA damage might be involved. These results suggest that the combination of PKM2-IN-1 and NCT-503 might be a potential strategy for the therapy of lung cancer.

PHB3 Is Required for the Assembly and Activity of Mitochondrial ATP Synthase in Arabidopsis

Mitochondrial ATP synthase is a multiprotein complex, which consists of a matrix-localized F1 domain (F1-ATPase) and an inner membrane-embedded Fo domain (Fo-ATPase). The assembly process of mitochondrial ATP synthase is complex and requires the function of many assembly factors. Although extensive studies on mitochondrial ATP synthase assembly have been conducted on yeast, much less study has been performed on plants. Here, we revealed the function of Arabidopsis prohibitin 3 (PHB3) in mitochondrial ATP synthase assembly by characterizing the phb3 mutant. The blue native PAGE (BN-PAGE) and in-gel activity staining assays showed that the activities of ATP synthase and F1-ATPase were significantly decreased in the phb3 mutant. The absence of PHB3 resulted in the accumulation of the Fo-ATPase and F1-ATPase intermediates, whereas the abundance of the Fo-ATPase subunit a was decreased in the ATP synthase monomer. Furthermore, we showed that PHB3 could interact with the F1-ATPase subunits β and δ in the yeast two-hybrid system (Y2H) and luciferase complementation imaging (LCI) assay and with Fo-ATPase subunit c in the LCI assay. These results indicate that PHB3 acts as an assembly factor required for the assembly and activity of mitochondrial ATP synthase.

Temporal Coordination of the Transcription Factor Response to H2O2 stress

Oxidative stress from excess H2O2 activates transcription factors (TFs) that restore redox balance and repair oxidative damage. Though many TFs are activated by H2O2, it is unknown whether they are activated at the same H2O2 concentration or time after H2O2 stress. We found TF activation is tightly coordinated over time and dose dependent. We first focused on p53 and FOXO1 and found that in response to low H2O2, p53 is activated rapidly while FOXO1 remains inactive. In contrast, cells respond to high H2O2 in two temporal phases. In the first phase FOXO1 rapidly shuttles to the nucleus while p53 remains inactive. In the second phase FOXO1 shuts off and p53 levels rise. Other TFs are activated in the first phase with FOXO1 (NF-κB, NFAT1), or the second phase with p53 (NRF2, JUN), but not both. The two phases result in large differences in gene expression. Finally, we provide evidence that 2-Cys peroxiredoxins control which TF are activated and the timing of TF activation.

Research progress on the interaction between oxidative stress and platelets: Another avenue for cancer?

Oxidative stress (OS) is a chemical imbalance between an oxidant and an antioxidant, causing damage to redox signaling and control or causing molecular damage. Unbalanced oxidative metabolism can produce excessive reactive oxygen species (ROS). These excess ROS can cause drastic changes in platelet metabolism and further affect platelet function. It will also lead to an increase in platelet procoagulant phenotype and cell apoptosis, which will increase the risk of thrombosis. The creation of ROS and subsequent platelet activation, adhesion, and recruitment are then further encouraged in an auto-amplifying loop by ROS produced from platelets. Meanwhile, cancer cells produce a higher concentration of ROS due to their fast metabolism and high proliferation rate. However, excessive ROS can result in damage to and modification of cellular macromolecules. The formation of cancer and its progression is strongly associated with oxidative stress and the resulting oxidative damage. In addition, platelets are an important part of the tumor microenvironment, and there is a significant cross-communication between platelets and cancer cells. Cancer cells alter the activation status of platelets, their RNA spectrum, proteome, and other properties. The "cloaking" of cancer cells by platelets providing physical protection，avoiding destruction from shear stress and the attack of immune cells, promoting tumor cell invasion.We explored the vicious circle interaction between ROS, platelets, and cancer in this review, and we believe that ROS can play a stimulative role in tumor growth and metastasis through platelets.

KDELC2 Upregulates Glioblastoma Angiogenesis via Reactive Oxygen Species Activation and Tumor-Associated Macrophage Proliferation

Glioblastoma is notorious for its rapid progression and neovascularization. In this study, it was found that KDEL (Lys-Asp-Glu-Leu) containing 2 (KDELC2) stimulated vasculogenic factor expression and induced human umbilical vein endothelial cell (HUVEC) proliferation. The NLRP3 inflammasome and autophagy activation via hypoxic inducible factor 1 alpha (HIF-1α) and mitochondrial reactive oxygen species (ROS) production was also confirmed. The application of the NLRP3 inflammasome inhibitor MCC950 and autophagy inhibitor 3-methyladenine (3-MA) indicated that the above phenomenon activation correlated with an endothelial overgrowth. Furthermore, KDELC2 suppression decreased the endoplasmic reticulum (ER) stress factors' expression. The ER stress inhibitors, such as salubrinal and GSK2606414, significantly suppressed HUVEC proliferation, indicating that ER stress promotes glioblastoma vascularization. Finally, shKDELC2 glioblastoma-conditioned medium (CM) stimulated TAM polarization and induced THP-1 cells to transform into M1 macrophages. In contrast, THP-1 cells co-cultured with compensatory overexpressed (OE)-KDELC2 glioblastoma cells increased IL-10 secretion, a biomarker of M2 macrophages. HUVECs co-cultured with shKDELC2 glioblastoma-polarized THP-1 cells were less proliferative, demonstrating that KDELC2 promotes angiogenesis. Mito-TEMPO and MCC950 increased caspase-1p20 and IL-1β expression in THP-1 macrophages, indicating that mitochondrial ROS and autophagy could also interrupt THP-1-M1 macrophage polarization. In conclusion, mitochondrial ROS, ER stress, and the TAMs resulting from OE-KDELC2 glioblastoma cells play important roles in upregulating glioblastoma angiogenesis.

Potentiation of Apoptotic Effect of Combination of Etoposide and Quercetin on HepG2 Liver Cancer Cells

Background: Hepatocellular carcinoma (HCC) is the most common type of liver cancer worldwide. The current remedies for cancer, including chemotherapy and radiation therapy, might damage patients’ organs, sometimes causing death. Etoposide (ETO), as a widely used chemo-drug, possesses the same problems. For years, combinational therapy has been considered a potential adjustor for common treatments, alleviating their side effects. Quercetin (Que), a phytochemical drug, has been used due to its potential against cancer. Objectives: This study explored whether synergy occurs between Que and ETO on the apoptosis of HepG2 HCC cells or not. Methods: The impacts of the drugs on cell growth were assessed through the MTT assay. The apoptotic death rates of treated cells were examined through Annexin/PI double staining and caspase-9 and caspase-3 activities. The relative expression of B-cell lymphoma 2 (Bcl-2) Associated X-protein (Bax), and Bcl-2 genes and proteins were analyzed using quantitative reverse transcription polymerase chain reaction and western blot analysis. Additionally, the levels of p53 protein were determined. Results: Both Que and ETO reduced the cell viability and increased apoptotic rates, caspases activities, Bax gene and protein expression, and the p53 protein levels of HepG2 cells. The combination of Que and ETO showed apparent synergy in terms of cell growth and cell apoptosis. Que significantly enhanced the effects of ETO on caspase activities, Bax and Bcl-2 genes’ expression, and p53 protein levels. Conclusions: The obtained results demonstrated that Que showed synergy when co-treated with ETO on HepG2 cells. Therefore, it is concluded that further studies on the aforementioned combination could lead to a potential anticancer compound against HCC.

RNA methylation and cellular response to oxidative stress-promoting anticancer agents

Disruption of the complex network that regulates redox homeostasis often underlies resistant phenotypes, which hinder effective and long-lasting cancer eradication. In addition, the RNA methylome-dependent control of gene expression also critically affects traits of cellular resistance to anti-cancer agents. However, few investigations aimed at establishing whether the epitranscriptome-directed adaptations underlying acquired and/or innate resistance traits in cancer could be implemented through the involvement of redox-dependent or -responsive signaling pathways. This is unexpected mainly because: i) the effectiveness of many anti-cancer approaches relies on their capacity to promote oxidative stress (OS); ii) altered redox milieu and reprogramming of mitochondrial function have been acknowledged as critical mediators of the RNA methylome-mediated response to OS. Here we summarize the current state of understanding on this topic, as well as we offer new perspectives that might lead to original approaches and strategies to delay or prevent the problem of refractory cancer and tumor recurrence.

Antioxidants attenuate mitochondrial oxidative damage through the Nrf2 pathway: A promising therapeutic strategy for stroke

Stroke represents one of the leading causes of disability and death worldwide. Reactive oxygen species overproduction-induced oxidative stress in mitochondria results in mitochondrial DNA damage, mitochondrial autophagy (mitophagy), inflammation, and apoptosis during the pathologic progression of stroke. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator that induces the transcription of a wide range of antioxidant genes to attenuate mitochondrial oxidative stress. Different antioxidative compounds, including polyphenols, mitochondrial antioxidants, triterpenoids, and others, have been shown to be able to activate Nrf2 and, thus, exert neuroprotective effects on stroke by ameliorating mitochondrial oxidative damage. In this review, we briefly discussed the role of mitochondrial oxidative stress in the pathophysiology of stroke and focused on the protective effects of antioxidative compounds through attenuating mitochondrial oxidative damage by activating Nrf2 in stroke. In conclusion, these antioxidants may represent novel therapeutic strategies against stroke.

Ameliorative effects of bilirubin on cell culture model of non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is defined as the most prevalent hepatic disorder that affects a significant population worldwide. There are several genes/proteins, involving in the modulation of NAFLD pathogenesis; sirtuin1 (SIRT1), TP53-inducible regulator gene (TIGAR), and autophagy-related gene 5 (Atg5) are considered a chief group of these modulators that principally act by regulating the hepatic lipid metabolism, as well as preventing the lipid accumulation. Surprisingly, bilirubin, especially in its unconjugated form, might be able to alleviate NAFLD progression by decreasing lipid accumulation and regulating the expression levels of the above-stated genes.

METHODS AND RESULTS

Herein, the interactions between bilirubin and the corresponding genes' products were first analyzed by docking assessments. Afterwards, HepG2 cells were cultured under the optimum conditions, and then were incubated with high concentrations of glucose to induce NAFLD. After treating normal and fatty liver cells with particular bilirubin concentrations for 24- and 48-hour periods, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay, colorimetric method, and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) were employed to assess cell viability status, intracellular triglycerides content, and mRNA expression levels of the genes, respectively. Intracellular lipid accumulation of HepG2 cells was significantly decreased after treating with bilirubin. Bilirubin also increased SIRT1 and Atg5 gene expression levels in fatty liver cells. TIGAR gene expression levels were variable upon the conditions and the cell type, suggesting a dual role for TIGAR during the NAFLD pathogenesis.

CONCLUSION

Our findings indicate the potential of bilirubin in the prevention from or amelioration of NAFLD through influencing SIRT1-related deacetylation and the process of lipophagy, as well as decreasing the intrahepatic lipid content. In vitro model of NAFLD was treated with unconjugated bilirubin under the optimal conditions.Desirably, bilirubin moderated the accumulation of triglycerides within the cells possibly through modulation of the expression of SIRT1, Atg5, and TIGAR genes. In the context, bilirubin was shown to increase the expression levels of SIRT1 and Atg5, while the expression of TIGAR was demonstrated to be either increased or decreased, depending on the treatment conditions. Created with BioRender.com.

Characterization of the interaction between the tumour suppressor p53 and heme and its role in the protein conformational dynamics studied by various spectroscopic techniques and hydrogen/deuterium exchange coupled with mass spectrometry

The tumour suppressor p53 regulates the expression of a myriad of proteins that are important for numerous cellular processes, including apoptosis, cell cycle arrest, DNA repair, metabolism, and even autophagy and ferroptosis. Aside from DNA, p53 can interact with many types of partners including proteins and small organic molecules. The ability of p53 to interact with heme has been reported so far. In this study, we used various spectroscopic studies to conduct a thorough biophysical characterization of the interaction between p53 and heme concerning the oxidation, spin, coordination, and ligand state of heme iron. We found that the p53 oligomeric state and zinc biding ability are preserved upon the interaction with heme. Moreover, we described the effect of heme binding on the conformational dynamics of p53 by hydrogen/deuterium exchange coupled with mass spectrometry. Specifically, the conformational flexibility of p53 is significantly increased upon interaction with heme, while its affinity to a specific DNA sequence is reduced by heme. The inhibitory effect of DNA binding by heme is partially reversible. We discuss the potential heme binding sites in p53 with respect to the observed conformational dynamics changes and perturbed DNA-binding ability of p53 upon interaction with heme.

Temporal Coordination of the Transcription Factor Response to H2O2 stress

The p53 and FOXO transcription factors (TFs) share many similarities despite their distinct evolutionary origins. Both TFs are activated by a variety of cellular stresses and upregulate genes in similar pathways including cell-cycle arrest and apoptosis. Oxidative stress from excess H2O2 activates both FOXO1 and p53, yet whether they are activated at the same time is unclear. Here we found that cells respond to high H2O2 levels in two temporal phases. In the first phase FOXO1 rapidly shuttles to the nucleus while p53 levels remain low. In the second phase FOXO1 exits the nucleus and p53 levels rise. We found that other oxidative stress induced TFs are activated in the first phase with FOXO1 (NF-κB, NFAT1), or the second phase with p53 (NRF2, JUN) but not both following H2O2 stress. The two TF phases result in large differences in gene expression patterns. Finally, we provide evidence that 2-Cys peroxiredoxins control the timing of the TF phases in response to H2O2.

A Mitochondrial Perspective on Noncommunicable Diseases

Mitochondria are the center of energy metabolism in eukaryotic cells and play a central role in the metabolism of living organisms. Mitochondrial diseases characterized by defects in oxidative phosphorylation are the most common congenital diseases. Meanwhile, mitochondrial dysfunction caused by secondary factors such as non-inherited genetic mutations can affect normal physiological functions of human cells, induce apoptosis, and lead to the development of various diseases. This paper reviewed several major factors and mechanisms that contribute to mitochondrial dysfunction and discussed the development of diseases closely related to mitochondrial dysfunction and drug treatment strategies discovered in recent years.

Thioredoxin Signaling Pathways in Cancer

Significance: Thioredoxin (Trx) is a powerful antioxidant that reduces protein disulfides to maintain redox stability in cells and is involved in regulating multiple redox-dependent signaling pathways. Recent Advance: The current accumulation of findings suggests that Trx participates in signaling pathways that interact with various proteins to manipulate their dynamic regulation of structure and function. These network pathways are critical for cancer pathogenesis and therapy. Promising clinical advances have been presented by most anticancer agents targeting such signaling pathways. Critical Issues: We herein link the signaling pathways regulated by the Trx system to potential cancer therapeutic opportunities, focusing on the coordination and strengths of the Trx signaling pathways in apoptosis, ferroptosis, immunomodulation, and drug resistance. We also provide a mechanistic network for the exploitation of therapeutic small molecules targeting the Trx signaling pathways. Future Directions: As research data accumulate, future complex networks of Trx-related signaling pathways will gain in detail. In-depth exploration and establishment of these signaling pathways, including Trx upstream and downstream regulatory proteins, will be critical to advancing novel cancer therapeutics. Antioxid. Redox Signal. 38, 403-424.

Aberrant activation of p53/p66Shc-mInsc axis increases asymmetric divisions and attenuates proliferation of aged mammary stem cells

Aging is accompanied by the progressive decline in tissue regenerative capacity and functions of resident stem cells (SCs). Underlying mechanisms, however, remain unclear. Here we show that, during chronological aging, self-renewing mitoses of mammary SCs (MaSCs) are preferentially asymmetric and that their progeny divides less frequently, leading to decreased number of MaSCs and reduced regenerative potential. Underlying mechanisms are investigated in the p66Shc-/- mouse, which exhibits several features of delayed aging, including reduced involution of the mammary gland (MG). p66Shc is a mitochondrial redox sensor that activates a specific p53 transcriptional program, in which the aging-associated p44 isoform of p53 plays a pivotal role. We report here that aged p66Shc-/- MaSCs show increased symmetric divisions, increased proliferation and increased regenerative potential, to an extent reminiscent of young wild-type (WT) MaSCs. Mechanistically, we demonstrate that p66Shc, together with p53: (i) accumulates in the aged MG, (ii) sustains expression of the cell polarity determinant mInscuteable and, concomitantly, (iii) down-regulates critical cell cycle genes (e.g.,: Cdk1 and Cyclin A). Accordingly, overexpression of p53/p44 increases asymmetric divisions and decreases proliferation of young WT MaSCs in a p66Shc-dependent manner and overexpression of mInsc restores WT-like levels of asymmetric divisions in aged p66Shc-/- MaSCs. Notably, deletion of p66Shc has negligible effects in young MaSCs and MG development. These results demonstrate that MG aging is due to aberrant activation of p66Shc, which induces p53/p44 signaling, leading to failure of symmetric divisions, decreased proliferation and reduced regenerative potential of MaSCs.

Hypoplasia of dopaminergic neurons by hypoxia-induced neurotoxicity is associated with disrupted swimming development of larval zebrafish

Hypoxic injury to the developing brain increases the risk of permanent behavioral deficits, but the precise mechanisms of hypoxic injury to the developing nervous system are poorly understood. In this study, we characterized the effects of developmental hypoxia (1% pO₂ from 24 to 48 h post-fertilization, hpf) on diencephalic dopaminergic (DA) neurons in larval zebrafish and the consequences on the development of swimming behavior. Hypoxia reduced the number of diencephalic DA neurons at 48 hpf. Returning zebrafish larvae to normoxia after the hypoxia (i.e., hypoxia-recovery, HR) induced reactive oxygen species (ROS) accumulation. Real-time qPCR results showed that HR caused upregulation of proapoptotic genes, including p53 and caspase3, suggesting the potential for ROS-induced cell death. With HR, we also found an increase in TUNEL-positive DA neurons, a persistent reduction in the number of diencephalic DA neurons, and disrupted swimming development and behavior. Interestingly, post-hypoxia (HR) with the antioxidant N-acetylcysteine partially restored the number of DA neurons and spontaneous swimming behavior, demonstrating potential recovery from hypoxic injury. The present study provides new insights for understanding the mechanisms responsible for motor disability due to developmental hypoxic injury.

Effect of Peroxiredoxin 6 on p53 Transcription Factor Level

Peroxiredoxin 6 (Prdx6) is an important antioxidant enzyme with multiple functions in the cell. Prdx6 neutralizes a wide range of hydroperoxides, participates in phospholipid metabolism and cell membrane repair, and in transmission of intracellular and intercellular signals. Disruption of normal Prdx6 expression in the cell leads to the development of pathological conditions. Decrease in the Prdx6 concentration leads to increase in oxidative damage to the cell. At the same time, hyperproduction of Prdx6 is associated with increase in antioxidant status, suppression of apoptosis, and carcinogenesis. Currently, mechanisms of carcinogenic action of peroxiredoxins are poorly understood. In this work we established that the 3-4-fold increase in Prdx6 production in mouse embryonic fibroblast 3T3 cells leads to the 4-5-fold decrease in the level of oncosuppressor p53. At the same time, hyperproduction of Prdx6 leads to the increased expression of RELA and HIF1A, which have oncogenic effects. The 3-4-fold increase in intracellular Prdx6 increases intensity of cell proliferation by 20-30%, promotes increase in antioxidant activity by 30-50%, and increases radioresistance of the transfected 3T3 cells by 30-40%. Increase of the level of intranuclear Prdx6 leads to the decrease in expression of the DNA repair genes in response to radiation, indicating decrease in the genomic DNA damage. This work discusses possible molecular mechanisms of p53 suppression during Prdx6 hyperproduction, which could be used in the development of new approaches in cancer therapy.

Whole-transcriptome sequencing identifies neuroinflammation, metabolism and blood-brain barrier related processes in the hippocampus of aged mice during perioperative period

AIM

Perioperative neurocognitive disorders (PND) occur frequently after surgery and anesthesia, especially in aged patients. Previous studies have shown multiple PND related mechanisms in the hippocampus; however, their relationships remain unclear. Meanwhile, the perioperative neuropathological processes are sophisticated and changeable, single period study could not reveal the accurate mechanisms. Thus, multiperiod whole-transcriptome study is necessary to elucidate the gene expression patterns during perioperative period.

METHODS

Aged C57BL/6 mice were subjected to exploratory laparotomy under sevoflurane anesthesia. Whole-transcriptome sequencing (RNA-seq analysis) was performed on the hippocampi from control condition (Con), 30 min (Day0), 2 days (Day2), and 7 days (Day7) after surgery. Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analyses, quantitative real-time PCR, immunofluorescence, and fear conditioning test were also performed to elucidate the pathological processes and modulation networks during the period.

RESULTS

Through RNA-seq analysis, 328, 3597, and 4179 differentially expressed genes (DEGs) were screened out in intraoperative period (Day0 vs. Con), early postoperative period (Day2 vs. Day0), and late postoperative period (Day7 vs. Day2). The involved GO biological processes were divided into 9 categories, and positive-regulated processes were more than negative-regulated ones. Seventy-four transcription factors were highlighted. The potential synaptic and neuroinflammatory pathways were constructed for Neurotransmitter, Synapse and Neuronal alteration categories with 9 genes (Htr1a, Rims1, and Ezh2, etc.). The metabolic and mitochondrial pathways were constructed for metabolism, oxidative stress, and biological rhythm categories with 9 genes (Gpld1, Sirt1, and Cry2, etc.). The blood-brain barrier and neurotoxicity related pathways were constructed for blood-brain barrier, neurotoxicity, and cognitive function categories with 10 genes (Mmp2, Itpr1, and Nrf1, etc.).

CONCLUSION

The results revealed gene expression patterns and modulation networks in the aged hippocampus during perioperative period, which provide insights into overall mechanisms and potential therapeutic targets for prevention and treatment of perioperative central nervous system diseases, such as PND, from the genetic level.

Defining roles of specific reactive oxygen species (ROS) in cell biology and physiology

'Reactive oxygen species' (ROS) is a generic term that defines a wide variety of oxidant molecules with vastly different properties and biological functions that range from signalling to causing cell damage. Consequently, the description of oxidants needs to be chemically precise to translate research on their biological effects into therapeutic benefit in redox medicine. This Expert Recommendation article pinpoints key issues associated with identifying the physiological roles of oxidants, focusing on H₂O₂ and O₂^.-. The generic term ROS should not be used to describe specific molecular agents. We also advocate for greater precision in measurement of H₂O₂, O₂^.- and other oxidants, along with more specific identification of their signalling targets. Future work should also consider inter-organellar communication and the interactions of redox-sensitive signalling targets within organs and whole organisms, including the contribution of environmental exposures. To achieve these goals, development of tools that enable site-specific and real-time detection and quantification of individual oxidants in cells and model organisms are needed. We also stress that physiological O₂ levels should be maintained in cell culture to better mimic in vivo redox reactions associated with specific cell types. Use of precise definitions and analytical tools will help harmonize research among the many scientific disciplines working on the common goal of understanding redox biology.

Glutor, a Glucose Transporter Inhibitor, Exerts Antineoplastic Action on Tumor Cells of Thymic Origin: Implication of Modulated Metabolism, Survival, Oxidative Stress, Mitochondrial Membrane Potential, pH Homeostasis, and Chemosensitivity

Neoplastic cells overexpress glucose transporters (GLUT), particularly GLUT1 and GLUT3, to support altered metabolism. Hence, novel strategies are being explored to effectively inhibit GLUTs for a daunting interference of glucose uptake. Glutor, a piperazine-2-one derivative, is a newly reported pan-GLUT inhibitor with a promising antineoplastic potential. However, several aspects of the underlying mechanisms remain obscure. To understand this better, tumor cells of thymic origin designated as Dalton's lymphoma (DL) were treated with glutor and analyzed for survival and metabolism regulatory molecular events. Treatment of tumor cells with glutor caused a decrease in cell survival with augmented induction of apoptosis. It also caused a decrease in glucose uptake associated with altered expression of GLUT1 and GLUT3. HIF-1α, HK-2, LDH-A, and MCT1 also decreased with diminished lactate production and deregulated pH homeostasis. Moreover, glutor treatment modulated the expression of cell survival regulatory molecules p53, Hsp70, IL-2 receptor CD25, and C-myc along with mitochondrial membrane depolarization, increased intracellular ROS expression, and altered Bcl-2/BAX ratio. Glutor also enhanced the chemosensitivity of tumor cells to cisplatin, accompanied by decreased MDR1 expression. Adding fructose to the culture medium containing glutor reversed the latter's inhibitory action on tumor cell survival. These results demonstrate that in addition to inhibited glucose uptake, modulated tumor growth regulatory molecular pathways are also implicated in the manifestation of the antineoplastic action of glutor. Thus, the novel findings of this study will have a long-lasting clinical significance in evaluating and optimizing the use of glutor in anticancer therapeutic strategies.

Gemcitabine-Loaded Nanocarrier of Essential Oil from Pulicaria crispa: Preparation, Optimization, and In Vitro Evaluation of Anticancer Activity

The limitations of gemcitabine (GEM) in cancer therapy are due to its poor pharmacokinetics, which cause undesired adverse effects. The current study was aimed at investigating the anticancer effect and apoptotic mechanism of synthesized nanoemulsion (NE) containing Pulicaria crispa essential oil (PC-EO) and GEM (PC-NE:GEM) on MCF-7 and Hep-G2 cancer cell lines. An optimized NE formulation was selected based on the Box–Behnken method. The droplet size of the optimized PC-NE was 9.93 ± 0.53 nm, but after GEM loading, it was increased to 11.36 ± 0.0.21 nm. Results from FTIR revealed that GEM was successfully loaded onto PC-NE. The antineoplastic effect of PC-NE:GEM on MCF-7 and Hep-G2 cancer cells was increased more than 100-fold relative to that of GEM. A combination index and isobologram based on CompuSyn software revealed the synergistic effect of the formulation produced by a 1:1 ratio combination of PC-NE and GEM. These findings were confirmed by examination of cellular morphologies. The combination formulation strongly induced about 4.48-fold and 2.95-fold increases in apoptosis in MCF-7 and Hep-G2 cells, respectively, when compared with GEM. Moreover, PC-NE:GEM produced a synergistic increase in ROS production in MCF-7 cells (15.23%) and Hep-G2 cells (31.69%), when compared with GEM. In addition, PC-NE:GEM enhanced the activation of the intrinsic apoptosis pathway through upregulation of expressions of p53 and Caspase-3, and downregulation of Bcl-2 expression in MCF-7 cells, while the expressions of Caspase-3, Bax, and p53 were upregulated in HepG2 cells. These results indicate that the GEM-loaded NE containing PC-EO may reduce the dose of GEM and eliminate the associated side effects.

Nimbolide retards T cell lymphoma progression by altering apoptosis, glucose metabolism, pH regulation, and ROS homeostasis

Nimbolide is reported as one of the potential anticancer candidates of the neem tree (Azadirachta indica A. Juss). The cytotoxic action of nimbolide has been well reported against a wide number of malignancies, including breast, prostate, lung, liver, and cervix cancers. Interestingly, only a few in vivo studies conducted on B cell lymphoma, glioblastoma, pancreatic cancer, and buccal pouch carcinoma have shown the in vivo antitumor efficacy of nimbolide. Therefore, it is highly needed to examine the in vivo antineoplastic activity of nimbolide on a wide variety of cancers to establish nimbolide as a promising anticancer drug. In the present study, we investigated the tumor retarding action of nimbolide in a murine model of T cell lymphoma. We noticed significantly augmented apoptosis in nimbolide- administered tumor-bearing mice, possibly due to down-regulated expression of Bcl2 and up-regulated expression of p53, cleaved caspase-3, Cyt c, and ROS. The nimbolide treatment-induced ROS production by suppressing the expression of antioxidant regulatory enzymes, namely superoxide dismutase and catalase. In addition, nimbolide administration impaired glycolysis and pH homeostasis with concomitant inhibition of crucial glycolysis and pH regulatory molecules such as GLUT3, LDHA, MCT1, and V-ATPase, CAIX and NHE1, respectively. Taken together, the present investigation provides novel insights into molecular mechanisms of nimbolide inhibited T cell lymphoma progression and directs the utility of nimbolide as a potential anticancer therapeutic drug for the treatment of T cell lymphoma.

Cytosolic p53 Inhibits Parkin-Mediated Mitophagy and Promotes Acute Liver Injury Induced by Heat Stroke

Heat stroke (HS) is a severe condition characterized by increased morbidity and high mortality. Acute liver injury (ALI) is a well-documented complication of HS. The tumor suppressor p53 plays an important role in regulation of mitochondrial integrity and mitophagy in several forms of ALI. However, the role of p53-regulated mitophagy in HS-ALI remains unclear. In our study, we discovered the dynamic changes of mitophagy in hepatocytes and demonstrated the protective effects of mitophagy activation on HS-ALI. Pretreatment with 3-MA or Mdivi-1 significantly exacerbated ALI by inhibiting mitophagy in HS-ALI mice. Consistent with the animal HS-ALI model results, silencing Parkin aggravated mitochondrial damage and apoptosis by inhibiting mitophagy in HS-treated normal human liver cell line (LO2 cells). Moreover, we described an increase in the translocation of p53 from the nucleus to the cytoplasm, and cytosolic p53 binds to Parkin in LO2 cells following HS. p53 overexpression using a specific adenovirus or Tenovin-6 exacerbated HS-ALI through Parkin-dependent mitophagy both in vivo and in vitro, whereas inhibition of p53 using siRNA or PFT-α effectively reversed this process. Our results demonstrate that cytosolic p53 binds to Parkin and inhibits mitophagy by preventing Parkin's translocation from the cytosol to the mitochondria, which decreases mitophagy activation and leads to hepatocyte apoptosis in HS-ALI. Overall, pharmacologic induction of mitophagy by inhibiting p53 may be a promising therapeutic approach for HS-ALI treatment.

Urea transporter B downregulates polyamines levels in melanoma B16 cells via p53 activation

Urea transporter B (UT-B, encoded by the SLC14A1 gene) is a membrane channel protein involved in urea transmembrane transport. Compared with normal tissues, UT-B expression is significantly decreased in most tumours, especially melanoma. However, the UT-B role in tumorigenesis and development is still unclear. Herein, we investigated the effects of UT-B overexpression on polyamine metabolism and the urea cycle in murine melanoma B16 cells, to explore the roles of mitochondrial dysfunction and p53 activation in cell growth and polyamines metabolism. UT-B overexpression in B16 cells decreased cell growth, increased apoptosis, and significantly altered metabolic pathways related to the urea cycle, which were characterized by reduced production of urea and polyamines and increased production of nitric oxide. Subsequently, we observed that activation of the p53 pathway may be the main cause of the above phenomena. The p53 inhibitor pifithrin-α partially restored the production of polyamines, but the mitochondrial morphology and function were still impaired. Further treatment of UT-B-overexpressing B16 cells with reactive oxygen species scavenging agent N-acetyl-l-cysteine and coenzyme Q10 restored cell viability and mitochondrial function and increased polyamine production. In conclusion, UT-B overexpression caused mitochondrial dysfunction and increased oxidative stress in B16 cells, and then activated p53 expression, which may be one of the mechanisms leading to the decrease in intracellular polyamines.

Anticancer potential and through study of the cytotoxicity mechanism of ionic liquids that are based on the trifluoromethanesulfonate and bis(trifluoromethylsulfonyl)imide anions

Ionic liquids (ILs) are known for their unique physicochemical properties. However, despite the great number of published papers, still little attention has been paid to their biological activity. Anticancer potential and the molecular mechanisms underlying the toxicity of these compounds are especially interesting and still unexplored. In the current work, a broad analysis of the cytotoxicity towards colon and breast cancers as well as glioblastoma of the ILs with pyridinium, piperidinium, pyrrolidinium, and imidazolium cations and trifluoromethanesulfonate or bis(trifluoromethylsulfonyl)imide anions indicated previously as the most toxic for normal human dermal fibroblasts were presented. In the case of MCF-7 cells, the activity of 1-decyl-3-methylimidazolium trifluoromethanesulfonate was more than twice as high as cisplatin. It was found that the inhibition of the cell cycle of colon cancer and glioblastoma cells occurs in different phases. More importantly, the different types of cell death were detected for both selected ILs, namely 1-hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and 1-hexyl-3-methylimidazolium trifluoromethane-sulfonate, on colon cancer and glioblastoma, respectively, apoptosis and autophagy, confirmed at the gene and protein levels. Additionally, kinetic studies of the reactive oxygen species indicated that the tested ILs disturbed the cellular redox homeostasis.

Mechano-signaling via Piezo1 prevents activation and p53-mediated senescence of muscle stem cells

Skeletal muscle stem cells (MuSCs), also called satellite cells, are instrumental for postnatal muscle growth and skeletal muscle regeneration. Numerous signaling cascades regulate the fate of MuSCs during muscle regeneration but the molecular mechanism by which MuSCs sense mechanical stimuli remain unclear. Here, we describe that Piezo1, a mechanosensitive ion channel, keeps MuSCs in a quiescent state and prevents senescence. Absence of Piezo1 induces precocious activation of MuSCs, attenuates proliferation, and impairs differentiation, essentially abolishing efficient skeletal muscle regeneration and replenishment of the MuSC pool. Furthermore, we discovered that inactivation of Piezo1 results in compensatory up-regulation of T-type voltage-gated Ca2+ channels, leading to increased Ca²⁺ influx, which strongly induces NOX4 expression via cPKC. Elevated NOX4 expression in Piezo1-deficient MuSCs increases ROS levels and DNA damage, causing P53-dependent cellular senescence and cell death. The importance of the P53/P21-axis for mediating Piezo1-dependent cellular defects was confirmed by pharmacological inhibition of P53 in Piezo1-deficient mice, which abrogates increased senescence of muscle cells and normalizes muscle regeneration. Our findings uncover an essential role of Piezo1-mediated mechano-signaling in MuSCs for maintaining quiescence and preventing senescence. Reduced mechano-signaling due to decreased physical activity during aging may contribute to the increase of senescent cells and the decline of MuSC numbers in geriatric mice and humans.

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Piezo1 is highly expressed in skeletal MuSCs and prevents their precocious activation.

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Loss of Piezo1 increases Ca²⁺ influx into MuSCs, which induces NOX4 expression via PKC, leading to enhanced ROS generation.

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Inactivation of Piezo1 depletes the MuSC pool and causes P53-dependent senescence of MuSCs.

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ROS scavenging in Piezo1-deficient MuSCs prevents P53 accumulation.

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Inhibition of P53 mitigates skeletal muscle regeneration defects in mice with Piezo1-deficient MuSCs.