High glucose-induced p53 phosphorylation contributes to impairment of endothelial antioxidant system

SETD7 drives diabetic endothelial dysfunction through FBXO45-mediated GPX4 ubiquitylation

BACKGROUND

Vasculopathy is the most prevalent complication of diabetes. Endothelial damage, a primary contributor to hyperglycemic vascular complications, impacts macro- and micro-vasculatures, causing functional impairment of multiple organs. SETD7 was initially identified as a transcriptional activator based on its ability to methylate histone 3 lysine 4. However, its function in the context of diabetic endothelial dysfunction remains poorly understood. This study aims to elucidate the involvement and underlying mechanisms of SETD7 in diabetic endothelial dysfunction.

METHODS

SETD7 knockout mice were generated to investigate the effects of SETD7 on Streptozotocin (STZ)-induced hyperglycemia and vascular endothelial injury. Endothelial-specific SETD7 interruption adeno-associated virus (AAV) system was utilized to investigate the effects of SETD7 on diabetic vascular endothelial injury in BKS-DB(Lepr) KO/KO (db/db) mice. In vitro manipulation of SETD7 activation or knockdown was conducted to assess its regulation on the lipid peroxidation, oxidative stress, and cell function of primary rat aortic endothelial cells (RAECs) under high glucose conditions.

RESULTS

Our study revealed that knockout and endothelial deficiency of SETD7 partially restored damaged vascular function and attenuated the inflammatory response caused by high glucose in both STZ-induced and db/db mice. Moreover, SETD7 activation aggravated oxidative stress injury and resulted in profound dysfunction through Glutathione Peroxidase 4 (GPX4)-mediated lipid peroxidation in RAECs. Mechanistically, SETD7 deficiency reduced p53 mono-methylation and blocked FBXO45 transcription, thereby inhibiting the protein degradation of GPX4 and subsequent lipid peroxidation as well as oxidative stress.

CONCLUSIONS

In summary, our study demonstrates that SETD7-p53-FBXO45-GPX4 is involved in high glucose-induced oxidative stress injury and exacerbated endothelial dysfunction, which offering great significance for mitigating hyperglycemia-induced endothelial damage.

Chaperone-assisted E3 ligase-engineered mesenchymal stem cells target hyperglycemia-induced p53 for ubiquitination and proteasomal degradation ameliorates self-renewal

BACKGROUND

Stem cell therapies may potentially be used in regenerative and reconstructive medicine due to their ability for self-renewal and differentiation. Stressful conditions, such as hyperglycemia, adversely affect stem cell functions, impairing their function and promoting differentiation by opposing self-renewal. The carboxyl terminus of HSP70 interacting protein (CHIP), which is a cochaperone and E3 ligase, maintains protein homeostasis and performs quality control of the cell via ubiquitylation. However, the role of CHIP in regulating stemness remains unknown.

RESULTS

Hyperglycemia downregulated CHIP-induced p53, arrested the cell cycle at the gap (G1) phase, and promoted the loss of stemness in WJMSCs. Quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, immunofluorescence, and cell cycle analysis showed that CHIP-overexpressing WJMSCs downregulated the expression of phosphorylated p53 and shortened its half-life while enhancing self-renewal factors. Additionally, co-IP and Western blotting revealed that CHIP promoted the ubiquitination and proteasomal degradation of hyperglycemia-induced p53 through the chaperone system.

CONCLUSIONS

CHIP may promote ubiquitin-mediated proteasomal degradation of hyperglycemia-induced p53 rescues self-renewal genes, which can maintain the long-term undifferentiated state of WJMSCs. CHIP may be an alternative therapeutic option in regenerative medicine for hyperglycemic-related complications in diabetes.

Working title: Molecular involvement of p53-MDM2 interactome in gastrointestinal cancers

The interaction between murine double minute 2 (MDM2) and p53, marked by transcriptional induction and feedback inhibition, orchestrates a functional loop dictating cellular fate. The functional loop comprising p53-MDM2 axis is made up of an interactome consisting of approximately 81 proteins, which are spatio-temporally regulated and involved in DNA repair mechanisms. Biochemical and genetic alterations of the interactome result in dysregulation of the p53-mdm2 axis that leads to gastrointestinal (GI) cancers. A large subset of interactome is well known and it consists of proteins that either stabilize p53 or MDM2 and proteins that target the p53-MDM2 complex for ubiquitin-mediated destruction. Upstream signaling events brought about by growth factors and chemical messengers invoke a wide variety of posttranslational modifications in p53-MDM2 axis. Biochemical changes in the transactivation domain of p53 impact the energy landscape, induce conformational switching, alter interaction potential and could change solubility of p53 to redefine its co-localization, translocation and activity. A diverse set of chemical compounds mimic physiological effectors and simulate biochemical modifications of the p53-MDM2 interactome. p53-MDM2 interactome plays a crucial role in DNA damage and repair process. Genetic aberrations in the interactome, have resulted in cancers of GI tract (pancreas, liver, colorectal, gastric, biliary, and esophageal). We present in this article a review of the overall changes in the p53-MDM2 interactors and the effectors that form an epicenter for the development of next-generation molecules for understanding and targeting GI cancers.

Association between inflammatory biomarkers and mortality in individuals with type 2 diabetes: NHANES 2005-2018

PURPOSE

This study aimed to examine independent association between inflammatory biomarkers and all-cause mortality as well as cardio-cerebrovascular disease (CCD) mortality among U.S. adults with diabetes.

METHODS

A cohort of 6412 U.S. adults aged 20 or older was followed from the start until December 31, 2019. Statistical models such as Cox proportional hazards model (Cox) and Kaplan-Meier (K-M) survival curves were employed to investigate the associations between the inflammatory biomarkers and all-cause mortality and CCD mortality.

RESULTS

After adjusting for confounding factors, the highest quartile of inflammatory biomarkers (NLR HR = 1.99; 95 % CI:1.54-2.57, MLR HR = 1.93; 95 % CI:1.46-2.54, SII HR = 1.49; 95 % CI:1.18-1.87, SIRI HR = 2.32; 95 % CI:1.81-2.96, nLPR HR = 2.05; 95 % CI:1.61-2.60, dNLR HR = 1.94; 95 % CI:1.51-2.49, AISI HR = 1.73; 95 % CI:1.4 1-2.12)) were positively associated with all-cause mortality compared to those in the lowest quartile. K-M survival curves indicated that participants with an inflammatory biomarker above a certain threshold had a higher risk of both all-cause mortality and CCD mortality (Log rank P < 0.05).

CONCLUSION

Some biomarkers such as NLR, MLR, SII, AISI, SIRI, and dNLR, are significantly associated with all-cause mortality and CCD mortality among U.S. adults with diabetes. The risk of both outcomes increased when the biomarkers surpassed a specific threshold.

Interleukin-30 subverts prostate cancer-endothelium crosstalk by fostering angiogenesis and activating immunoregulatory and oncogenic signaling pathways

BACKGROUND

Cancer-endothelial interplay is crucial for tumor behavior, yet the molecular mechanisms involved are largely unknown. Interleukin(IL)-30, which is expressed as a membrane-anchored cytokine by human prostate cancer (PC) cells, promotes PC vascularization and progression, but the underlying mechanisms have yet to be fully explored.

METHODS

PC-endothelial cell (EC) interactions were investigated, after coculture, by flow cytometry, transcriptional profiling, western blot, and ELISA assays. Proteome profiler phospho-kinase array unveiled the molecular pathways involved. The role of tumor-derived IL30 on the endothelium's capacity to generate autocrine circuits and vascular budding was determined following IL30 overexpression, by gene transfection, or its deletion by CRISPR/Cas9 genome editing. Clinical value of the experimental findings was determined through immunopathological study of experimental and patient-derived PC samples, and bioinformatics of gene expression profiles from PC patients.

RESULTS

Contact with PC cells favors EC proliferation and production of angiogenic and angiocrine factors, which are boosted by PC expression of IL30, that feeds autocrine loops, mediated by IGF1, EDN1, ANG and CXCL10, and promotes vascular budding and inflammation, via phosphorylation of multiple signaling proteins, such as Src, Yes, STAT3, STAT6, RSK1/2, c-Jun, AKT and, primarily CREB, GSK-3α/β, HSP60 and p53. Deletion of the IL30 gene in PC cells inhibits endothelial expression of IGF1, EDN1, ANG and CXCL10 and substantially impairs tumor angiogenesis. In its interaction with IL30-overexpressing PC cells the endothelium boosts their expression of a wide range of immunity regulatory genes, including CCL28, CCL4, CCL5, CCR2, CCR7, CXCR4, IL10, IL13, IL17A, FASLG, IDO1, KITLG, TNFA, TNFSF10 and PDCD1, and cancer driver genes, including BCL2, CCND2, EGR3, IL6, VEGFA, KLK3, PTGS1, LGALS4, GNRH1 and SHBG. Immunopathological analyses of PC xenografts and in silico investigation of 1116 PC cases, from the Prostate Cancer Transcriptome Atlas, confirmed the correlation between the expression of IL30 and that of both pro-inflammatory genes, NOS2, TNFA, CXCR5 and IL12B, and cancer driver genes, LGALS4, GNRH1 and SHBG, which was validated in a cohort of 80 PC patients.

CONCLUSIONS

IL30 regulates the crosstalk between PC and EC and reshapes their transcriptional profiles, triggering angiogenic, immunoregulatory and oncogenic gene expression programs. These findings highlight the angiostatic and oncostatic efficacy of targeting IL30 to fight PC.

Transcriptomic signature related to poor welfare of sport horses

The improvement of horse welfare through housing conditions has become a real issue in recent years and have highlighted the detrimental effect of individual housing of horses on their health and behaviour. In this new study, we analysed the blood transcriptome of 45 sport horses housed individually that were previously examined for their behaviour and gut microbiota. We performed differential and regression analyses of gene expression, followed by downstream bioinformatic analyses, to unveil the molecular pathways related to the behavioural changes associated with welfare impairment in these sport horses. We found that aggressiveness towards humans was the behavioural indicator the most correlated to blood gene expression and that the pathways involved belonged mainly to systemic inflammation. In contrast, the correlations between genes, alert postures and unresponsiveness towards the environment were weak. When blood gene expression profiling was combined with faecal microbiota of a sub-population of horses, stereotypies came out as the most correlated to blood gene expression. This study shows that aggressiveness towards humans and stereotypies are behavioural indicators that covary with physiological alterations. Further studies are needed regarding the biological correlates of unresponsiveness to the environment and alert postures.

Single-cell RNA sequencing reveals the effects of capsaicin in the treatment of sepsis-induced liver injury

Sepsis is a difficult-to-treat systemic condition in which liver dysfunction acts as both regulator and target. However, the dynamic response of diverse intrahepatic cells to sepsis remains poorly characterized. Capsaicin (CAP), a multifunctional chemical derived from chilli peppers, has recently been shown to potentially possess anti-inflammatory effects, which is also one of the main approaches for drug discovery against sepsis. We performed single-cell RNA transcriptome sequencing on 86,830 intrahepatic cells isolated from normal mice, cecal ligation and puncture-induced sepsis model mice and CAP-treated mice. The transcriptional atlas of these cells revealed dynamic changes in hepatocytes, macrophages, neutrophils, and endothelial cells in response to sepsis. Among the extensive crosstalk across these major subtypes, KC_Cxcl10 shared strong potential interaction with other cells when responding to sepsis. CAP mitigated the severity of inflammation by partly reversing these pathophysiologic processes. Specific cell subpopulations in the liver act collectively to escalate inflammation, ultimately causing liver dysfunction. CAP displays its health-promoting function by ameliorating liver dysfunction induced by sepsis. Our study provides valuable insights into the pathophysiology of sepsis and suggestions for future therapeutic gain.

Maintaining Genome Integrity: Protein Kinases and Phosphatases Orchestrate the Balancing Act of DNA Double-Strand Breaks Repair in Cancer

DNA double-strand breaks (DSBs) are the most lethal DNA damages which lead to severe genome instability. Phosphorylation is one of the most important protein post-translation modifications involved in DSBs repair regulation. Kinases and phosphatases play coordinating roles in DSB repair by phosphorylating and dephosphorylating various proteins. Recent research has shed light on the importance of maintaining a balance between kinase and phosphatase activities in DSB repair. The interplay between kinases and phosphatases plays an important role in regulating DNA-repair processes, and alterations in their activity can lead to genomic instability and disease. Therefore, study on the function of kinases and phosphatases in DSBs repair is essential for understanding their roles in cancer development and therapeutics. In this review, we summarize the current knowledge of kinases and phosphatases in DSBs repair regulation and highlight the advancements in the development of cancer therapies targeting kinases or phosphatases in DSBs repair pathways. In conclusion, understanding the balance of kinase and phosphatase activities in DSBs repair provides opportunities for the development of novel cancer therapeutics.

Research progress on the mechanism of ferroptosis and its role in diabetic retinopathy

Ferroptosis is iron-dependent regulatory cell death (RCD). Morphologically, ferroptosis is manifested as mitochondrial atrophy and increased mitochondrial membrane density. Biochemically, ferroptosis is characterized by the depletion of glutathione (GSH), the inactivation of glutathione peroxidase 4 (GPX4), and an increase in lipid peroxides (LPO)and divalent iron ions. Ferroptosis is associated with various diseases, but the relationship with diabetic retinopathy(DR) is less studied. DR is one of the complications of diabetes mellitus and has a severe impact on visual function. The pathology of DR is complex, and the current treatment is unsatisfactory. Therefore, exploring pathogenesis is helpful for the clinical treatment of DR. This paper reviews the pathological mechanism of ferroptosis and DR in recent years and the involvement of ferroptosis in the pathology of DR. In addition, we propose problems that need to be addressed in this research field. It is expected to provide new ideas for treating DR by analyzing the role of ferroptosis in DR.

Growth Hormone-Releasing Hormone Antagonist JV-1-36 Suppresses Reactive Oxygen Species Generation in A549 Lung Cancer Cells

Growth hormone-releasing hormone (GHRH) and its receptors are expressed in a variety of human cancers, and have been involved in malignancies. GHRH antagonists (GHRHAnt) were developed to suppress tumor progression and metastasis. Previous studies demonstrate the involvement of reactive oxygen species (ROS) in cancer progression. Herein, we investigate the effect of a commercially available GHRH antagonist, namely JV-1-36, in the redox status of the A549 human cancer cell line. Our results suggest that this peptide significantly reduces ROS production in those cells in a time-dependent manner and counteracts H2O2-induced ROS. Our study supports the anti-oxidative effects of JV-1-36 and contributes in our knowledge towards the in vitro effects of GHRHAnt in cancers.

Targeting ferroptosis with miR-144-3p to attenuate pancreatic β cells dysfunction via regulating USP22/SIRT1 in type 2 diabetes

BACKGROUND

Recently, ferroptosis has been implicated in the pathologic process of several diseases including type 2 diabetes mellitus (T2DM). However, molecular mechanisms underlying ferroptosis in T2DM remain obscure.

METHODS

Twenty four mice were included in this study. T2DM model mice were established by a high-fat diet combined with streptozotocin injection. INS-1 cells were stimulated with high glucose (HG). Cell viability was detected by CCK-8 kit. The levels of GSH, MDA, iron, and lipid ROS, and SOD activity, were detected by the corresponding kits. The interaction between miR-144-3p and USP22 was validated by dual-luciferase reporter assay. The relationship between USP22 and its substrate was verified using Co-IP and ubiquitination assays. The mRNA and protein expressions were examined by RT-qPCR and western blot, respectively. The functions of β cells in vitro and in vivo were evaluated glucose-stimulated insulin secretion test and HOMA-β, respectively.

RESULTS

Ferroptosis occurred in the pancreas of T2DM mice and HG-induced INS-1 cells. Silencing miR-144-3p blocked the effect of HG on the cell viability and accumulation of lipid peroxides, thereby improving the insulin secretion in INS-1 cells. Mechanistically, USP22 is a direct target of miR-144-3p, which could stabilize SIRT1 expression, thereby suppressing ferroptosis. Overexpressing USP22 attenuated deleterious roles of HG in INS-1 cells; but its roles were reversed by up-regulating miR-144-3p. In vivo study demonstrated that miR-144-3p antagomir exerted an anti-hyperglycemic effect and regulated the ferroptosis-related proteins in the pancreas.

CONCLUSION

The up-regulation of miR-144-3p suppressed USP22/SIRT1 to induce ferroptosis, which causes pancreatic β cells dysfunction, thereby promoting T2DM development.

Glutathione Peroxidase GPX1 and Its Dichotomous Roles in Cancer

As the first identified selenoprotein, glutathione peroxidase 1 (GPX1) is a widely and abundantly expressed antioxidant enzyme. GPX1 utilizes glutathione as a substrate to catalyze hydrogen peroxide, lipid peroxide, and peroxynitrite, thereby reducing intracellular oxidative stress. The GPX1 gene is regulated at transcriptional, post-transcriptional, and translational levels. Numerous case-control studies and meta-analyses have assessed the association between a functional genetic polymorphism of the GPX1 gene, named Pro198Leu (rs1050450 C>T), and cancer susceptibility in different populations. GPX1 polymorphism has type-specific effects as a candidate marker for cancer risk, but the association between GPX1 variants and cancer susceptibility remains controversial in different studies. GPX1 is abnormally elevated in most types of cancer but has complex dichotomous roles as tumor suppressor and promoter in different cancers. GPX1 can participate in various signaling pathways to regulate tumor biological behaviors, including cell proliferation, apoptosis, invasion, immune response, and chemoresistance. In this review, we comprehensively summarize the controversial associations between GPX1 polymorphism and cancer risks and further discuss the relationships between the aberrant expressions of GPX1 and tumorigenesis. Further studies are needed to elucidate the clinical significance of GPX1 as a potential prognostic biomarker and novel therapeutic target in various malignancies.

Isoquercitrin protects HUVECs against high glucose‑induced apoptosis through regulating p53 proteasomal degradation

High glucose (HG)-induced endothelial apoptosis serves an important role in the vascular dysfunction associated with diabetes mellitus (DM). It has been reported that isoquercitrin (IQC), a flavonoid glucoside, possesses an anti-DM effect, but the mechanism requires further investigation. The present study investigated the effect of IQC against HG-induced apoptosis in human umbilical vein endothelial cells (HUVECs) and explored its molecular mechanism. HUVECs were treated with 5 or 30 mM glucose for 48 h. Endothelial cell viability was monitored using the Cell Counting Kit-8 assay. Mitochondrial membrane potential was detected by JC-1 staining. Apoptosis was observed by TUNEL staining and flow cytometry. Western blotting was used for the analysis of apoptosis-associated proteins Bax, Bcl-2, cleaved (C)-caspase3, total-caspase3, p53 and phosphorylated p53. Reverse transcription-quantitative PCR was used to analyze the mRNA expression levels of Bax, Bcl-2 and p53. Immunofluorescence staining was utilized to detect the expression levels and distribution of p53 and ubiquitin specific peptidase 10 (USP10) in HUVECs. The results revealed that IQC significantly attenuated HG-induced endothelial apoptosis, as shown by decreased apoptotic cells observed by TUNEL, JC-1 staining and flow cytometry. Moreover, under HG stress, IQC treatment markedly inhibited the increased expression levels of the pro-apoptotic proteins p53, Bax and C-caspase3, and increased the expression levels of the anti-apoptotic protein Bcl-2 in HUVECs. However, the anti-apoptotic effect of IQC against HG was partially blunted by increasing p53 protein levels in vitro. IQC influenced the mRNA expression levels of Bax and Bcl-2 in response to HG, but it did not affect the transcription of p53. Notably, IQC inhibited the HG-induced phosphorylation of p53 at Ser15 and the nuclear transport of USP10, destabilizing p53 and increasing the proteasomal degradation of the p53 protein. The current findings revealed that IQC exerted a protective effect against the HG-induced apoptosis of endothelial cells by regulating the proteasomal degradation of the p53 protein, suggesting that IQC may be used as a novel therapeutic compound to ameliorate DM-induced vascular complications.

Role of ferroptosis in the process of diabetes-induced endothelial dysfunction

BACKGROUND

Endothelial dysfunction, a hallmark of diabetes, is a critical and initiating contributor to the pathogenesis of diabetic cardiovascular complications. However, the underlying mechanisms are still not fully understood. Ferroptosis is a newly defined regulated cell death driven by cellular metabolism and iron-dependent lipid peroxidation. Although the involvement of ferroptosis in disease pathogenesis has been shown in cancers and degenerative diseases, the participation of ferroptosis in the pathogenesis of diabetic endothelial dysfunction remains unclear.

AIM

To examine the role of ferroptosis in diabetes-induced endothelial dysfunction and the underlying mechanisms.

METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with high glucose (HG), interleukin-1β (IL-1β), and ferroptosis inhibitor, and then the cell viability, reactive oxygen species (ROS), and ferroptosis-related marker protein were tested. To further determine whether the p53-xCT (the substrate-specific subunit of system Xc^-)-glutathione (GSH) axis is involved in HG and IL-1β induced ferroptosis, HUVECs were transiently transfected with p53 small interfering ribonucleic acid or NC small interfering ribonucleic acid and then treated with HG and IL-1β. Cell viability, ROS, and ferroptosis-related marker protein were then assessed. In addition, we detected the xCT and p53 expression in the aorta of db/db mice.

RESULTS

It was found that HG and IL-1β induced ferroptosis in HUVECs, as evidenced by the protective effect of the ferroptosis inhibitors, Deferoxamine and ferrostatin-1, resulting in increased lipid ROS and decreased cell viability. Mechanistically, activation of the p53-xCT-GSH axis induced by HG and IL-1β enhanced ferroptosis in HUVECs. In addition, a decrease in xCT and the presence of de-endothelialized areas were observed in the aortic endothelium of db/db mice.

CONCLUSION

Ferroptosis is involved in endothelial dysfunction and p53-xCT-GSH axis activation plays a crucial role in endothelial cell ferroptosis and endothelial dysfunction.

Effects of Cudrania tricuspidata on anti-senescence in high glucose-treated endothelial cells via the Akt/p53/p21 pathway

The roles of Cudrania tricuspidata (CT) in the prevention of senescence and the underlying mechanisms have not been elucidated. In a high glucose (HG)-induced senescent endothelial cell (EC) culture, CT (20 µg/ml) reduced the number of senescence-associated β-galactosidase-positive cells by 8.3% compared with the control group and increased the expression of p-Sirt1 by more than twofold compared with the control group. Moreover, 20 μg/ml CT treatment doubled the activity of p-Akt, which was inhibited by HG, compared with the control group. In addition, CT treatment decreased the expression of p53, p21, and Rb, which was increased by HG. Overall, CT delays HG-induced senescence via the Akt/p53/p21 pathway, suggesting its potential as a functional agent for the protection of ECs.

Dietary Flavonoids in p53-Mediated Immune Dysfunctions Linking to Cancer Prevention

The p53 protein plays a central role in mediating immune functioning and determines the fate of the cells. Its role as a tumor suppressor, and in transcriptional regulation and cytokine activity under stress conditions, is well defined. The wild type (WT) p53 functions as a guardian for the genome, while the mutant p53 has oncogenic roles. One of the ways that p53 combats carcinogenesis is by reducing inflammation. WT p53 functions as an anti-inflammatory molecule via cross-talk activity with multiple immunological pathways, such as the major histocompatibility complex I (MHCI) associated pathway, toll-like receptors (TLRs), and immune checkpoints. Due to the multifarious roles of p53 in cancer, it is a potent target for cancer immunotherapy. Plant flavonoids have been gaining recognition over the last two decades to use as a potential therapeutic regimen in ameliorating diseases. Recent studies have shown the ability of flavonoids to suppress chronic inflammation, specifically by modulating p53 responses. Further, the anti-oxidant Keap1/Nrf2/ARE pathway could play a crucial role in mitigating oxidative stress, leading to a reduction of chronic inflammation linked to the prevention of cancer. This review aims to discuss the pharmacological properties of plant flavonoids in response to various oxidative stresses and immune dysfunctions and analyzes the cross-talk between flavonoid-rich dietary intake for potential disease prevention.

Pharmacological management of vascular endothelial dysfunction in diabetes: TCM and western medicine compared based on biomarkers and biochemical parameters

Diabetes, a worldwide health concern while burdening significant populace of countries with time due to a hefty increase in both incidence and prevalence rates. Hyperglycemia has been buttressed both in clinical and experimental studies to modulate widespread molecular actions that effect macro and microvascular dysfunctions. Endothelial dysfunction, activation, inflammation, and endothelial barrier leakage are key factors contributing to vascular complications in diabetes, plus the development of diabetes-induced cardiovascular diseases. The recent increase in molecular, transcriptional, and clinical studies has brought a new scope to the understanding of molecular mechanisms and the therapeutic targets for endothelial dysfunction in diabetes. In this review, an attempt made to discuss up to date critical and emerging molecular signaling pathways involved in the pathophysiology of endothelial dysfunction and viable pharmacological management targets. Importantly, we exploit some Traditional Chinese Medicines (TCM)/TCM isolated bioactive compounds modulating effects on endothelial dysfunction in diabetes. Finally, clinical studies data on biomarkers and biochemical parameters involved in the assessment of the efficacy of treatment in vascular endothelial dysfunction in diabetes was compared between clinically used western hypoglycemic drugs and TCM formulas.

Reduced Sirtuin1 signalling exacerbates diabetic mice hindlimb ischaemia injury and inhibits the protective effect of a liver X receptor agonist

Diabetes mellitus causes endothelial dysfunction, which further exacerbates peripheral arterial disease (PAD). Improving endothelial function via reducing endothelial oxidative stress (OS) may be a promising therapy for diabetic PAD. Activation of liver X receptor (LXR) inhibits excessive OS and provides protective effects on endothelial cells in diabetic individuals. Therefore, we investigated the effects of LXR agonist treatment on diabetic PAD with a focus on modulating endothelial OS. We used a streptozotocin‐induced diabetes mouse model combined with a hindlimb ischaemia (HLI) injury to mimic diabetic PAD, which was followed by LXR agonist treatment. In our study, the LXR agonist T0901317 protected against HLI injury in diabetic mice by attenuating endothelial OS and stimulating angiogenesis. However, a deficiency in endothelial Sirtuin1 (SIRT1) largely inhibited the therapeutic effects of T0901317. Furthermore, we found that the underlying therapeutic mechanisms of T0901317 were related to SIRT1 and non‐SIRT1 signalling, and the isoform LXRβ was involved in LXR agonist‐elicited SIRT1 regulation. In conclusion, LXR agonist treatment protected against HLI injury in diabetic mice via mitigating endothelial OS and stimulating cellular viability and angiogenesis by LXRβ, which elicited both SIRT1‐mediated and non‐SIRT1‐mediated signalling pathways. Therefore, LXR agonist treatment may be a promising therapeutic strategy for diabetic PAD.

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

The nuclear transcription factor p53, discovered in 1979, has a broad range of biological functions, primarily the regulation of apoptosis, the cell cycle, and DNA repair. In addition to these canonical functions, a growing body of evidence suggests that p53 plays an important role in regulating intracellular redox homeostasis through transcriptional and nontranscriptional mechanisms. Oxidative stress induction and p53 activation are common responses to chemical exposure and are suggested to play critical roles in chemical-induced toxicity. The activation of p53 can exert either prooxidant or antioxidant activity, depending on the context. In this review, we discuss the functional role of p53 in regulating chemical-induced oxidative stress, summarize the potential signaling pathways involved in p53's regulation of chemically mediated oxidative stress, and propose issues that should be addressed in future studies to improve understanding of the relationship between p53 and chemical-induced oxidative stress.

Effect of High Glucose-Induced Oxidative Stress on Paraoxonase 2 Expression and Activity in Caco-2 Cells

(1) Background: Hyperglycemia leads to several biochemical and physiological consequences, such as the generation of advanced glycation end products (AGEs) and reactive oxygen species (ROS), which are involved in the development of several human diseases. Intestinal cells are continuously exposed to pro-oxidants and lipid peroxidation products from ingested foods, and also to glyco-oxidative damage. It has been reported that free radical generation may be linked to the development of inflammation-related gastrointestinal diseases. (2) Methods: The effects of high glucose (HG) treatment (50 mM) were assessed in terms of free radical production, lipid peroxidation, and AGEs formation. Furthermore, the expression and the antiapoptotic and antioxidant activity of the paraoxonase-2 (PON2) enzyme in intestinal cells has been investigated. (3) Results: Caco-2 cells treated with media supplied with high glucose (HG) (50 mM) showed, with respect to physiological glucose concentration (25 mM), an increase in ROS production, lipid peroxidation, and AGEs formation. Moreover, a lower PON2 expression and activity in HG-treated cells was related to activation of the apoptotic pathways. (4) Conclusions: Our results demonstrated that high glucose concentrations triggered glyco-oxidative stress in intestinal cells; the downregulation of PON2 could result in a higher oxidative stress and might contribute to intestinal dysfunction.

A reactive oxygen species scoring system predicts cisplatin sensitivity and prognosis in ovarian cancer patients

Background

To reveal roles of reactive oxygen species (ROS) status in chemotherapy resistance and to develop a ROS scoring system for prognosis prediction in ovarian cancer.

Methods

We tested the sensitizing effects of ROS elevating drugs to cisplatin (cDDP) in ovarian cancer both in vitro and in vivo. A ROS scoring system was developed using The Cancer Genome Atlas (TCGA) database of ovarian cancer. The associations between ROS scores and overall survival (OS) were analyzed in TCGA, Tothill dataset, and our in-house dataset (TJ dataset).

Results

ROS-inducing drugs increased cisplatin-induced ovarian cancer cell injury in vitro and in vivo. ROS scoring system was established using 25 ROS-related genes. Patients were divided into low (scores 0–12) and high (scores 13–25) score groups. Improved patient survival was associated with higher scores (TCGA dataset hazard ratio (HR) = 0.43, P < 0.001; Tothill dataset HR = 0.65, P = 0.022; TJ dataset HR = 0.40, P = 0.003). The score was also significantly associated with OS in multiple datasets (TCGA dataset r² = 0.574, P = 0.032; Thothill dataset r² = 0.266, P = 0.049; TJ dataset r² = 0.632, P = 0.001) and with cisplatin sensitivity in ovarian cancer cell lines (r² = 0.799, P = 0.016) when used as a continuous variable. The scoring system showed better prognostic performance than other clinical factors by receiver operating characteristic (ROC) curves (TCGA dataset area under the curve (AUC) = 0.71 v.s. 0.65, Tothill dataset AUC = 0.73 v.s. 0.67, TJ dataset AUC = 0.74 v.s. 0.66).

Conclusions

ROS status is associated with chemotherapy resistance. ROS score system might be a prognostic biomarker in predicting the survival benefit from ovarian cancer patients.

SUMOylation Evoked by Oxidative Stress Reduced Lens Epithelial Cell Antioxidant Functions by Increasing the Stability and Transcription of TP53INP1 in Age-Related Cataracts

Oxidative stress plays an important role in the pathogenesis of cataracts. Small ubiquitin-like modifier (SUMO) proteins have great effects on cell stress response. Previous studies have shown that TP53INP1 can arrest cell growth and induce apoptosis by modulating p53 transcriptional activity and that both TP53INP1 and p53 are substrates of SUMOylation. However, no previous research has studied the effect of SUMOylation on the oxidative stress response in cataracts. This is the first study to investigate the effect of SUMOylation of TP53INP1 in oxidative stress-induced lens epithelial cell injury and age-related cataract formation. We found that the oxidative stress-induced endogenous SUMOylation of TP53INP1 promoted human lens epithelial cell (holed) apoptosis and regulated hLEC antioxidant effects by increasing the stability and transcription of TP53INP1 in age-related cataracts. SUMO-1, SUMOylation, and TP53INP1 were upregulated in lens tissues affected by age-related cataracts. A SUMO-1-specific protease, SENP1, acted as an oxidative stress-sensitive target gene in hLECs. This study identified for the first time that TP53INP1 can be SUMOylated in vivo, that the SUMOylation of TP53INP1 is induced by oxidative stress, and that SUMOylation/deSUMOylation can affect the stability and transcription of TP53INP1 in hLECs.

Inhibition of P53/miR-34a improves diabetic endothelial dysfunction via activation of SIRT1

Endothelial dysfunction contributes to diabetic macrovascular complications, resulting in high mortality. Recent findings demonstrate a pathogenic role of P53 in endothelial dysfunction, encouraging the investigation of the effect of P53 inhibition on diabetic endothelial dysfunction. Thus, high glucose (HG)‐treated endothelial cells (ECs) were subjected to pifithrin‐α (PFT‐α)—a specific inhibitor of P53, or P53‐small interfering RNA (siRNA), both of which attenuated the HG‐induced endothelial inflammation and oxidative stress. Moreover, inhibition of P53 by PFT‐α or P53‐siRNA prohibited P53 acetylation, decreased microRNA‐34a (miR‐34a) level, leading to a dramatic increase in sirtuin 1 (SIRT1) protein level. Interestingly, the miR‐34a inhibitor (miR‐34a‐I) and PFT‐α increased SIRT1 protein level and alleviated the HG‐induced endothelial inflammation and oxidative stress to a similar extent; however, these effects of PFT‐α were completely abrogated by the miR‐34a mimic. In addition, SIRT1 inhibition by EX‐527 or Sirt1‐siRNA completely abolished miR‐34a‐I's protection against HG‐induced endothelial inflammation and oxidative stress. Furthermore, in the aortas of streptozotocin‐induced diabetic mice, both PFT‐α and miR‐34a‐I rescued the inflammation, oxidative stress and endothelial dysfunction caused by hyperglycaemia. Hence, the present study has uncovered a P53/miR‐34a/SIRT1 pathway that leads to endothelial dysfunction, suggesting that P53/miR‐34a inhibition could be a viable strategy in the management of diabetic macrovascular diseases.

SET8 is involved in the regulation of hyperglycemic memory in human umbilical endothelial cells

Hyperglycemic memory occurs in diabetic cardiovascular complications, but the underlying mechanism remains to be elucidated. Although the depletion of SET8 leads to increased mitochondrial oxidative stress via increasing cellular reactive oxygen species (ROS) production, the role of SET8 in hyperglycemic memory-induced mitochondrial dysfunction is not well understood. Here, we investigated the role of SET8 in this setting. Our results showed that high glucose-induced vascular inflammation, ROS production and apoptosis remained at high levels even when glucose returned to normal level. Elevated glucose reduced SET8 expression, which also remained at low level after returning to normoglycemia. SET8 overexpression protected cells from elevated glucose and hyperglycemic memory-induced endothelial injury by blocking ROS accumulation, attenuating vascular inflammation, and restoring nitric oxide production. Thus, our results suggest that SET8 may be a key mediator in hyperglycemic memory.

Impact of carbonylation on glutathione peroxidase-1 activity in human hyperglycemic endothelial cells

AIMS

High levels of glucose and reactive carbonyl intermediates of its degradation pathway such as methylglyoxal (MG) may contribute to diabetic complications partly via increased generation of reactive oxygen species (ROS). This study focused on glutathione peroxidase-1 (GPx1) expression and the impact of carbonylation as an oxidative protein modification on GPx1 abundance and activity in human umbilical vein endothelial cells (HUVEC) under conditions of mild to moderate oxidative stress.

RESULTS

High extracellular glucose and MG enhanced intracellular ROS formation in HUVECs. Protein carbonylation was only transiently augmented pointing to an effective antioxidant defense in these cells. Nitric oxide synthase expression was decreased under hyperglycemic conditions but increased upon exposure to MG, whereas superoxide dismutase expression was not significantly affected. Increased glutathione peroxidase (GPx) activity seemed to compensate for a decrease in GPx1 protein due to enhanced degradation via the proteasome. Mass spectrometry analysis identified Lys-114 as a possible carbonylation target which provides a vestibule for the substrate H2O2 and thus enhances the enzymatic reaction.

INNOVATION

Oxidative protein carbonylation has so far been associated with functional inactivation of modified target proteins mainly contributing to aging and age-related diseases. Here, we demonstrate that mild oxidative stress and subsequent carbonylation seem to activate protective cellular redox signaling pathways whereas severe oxidative stress overwhelms the cellular antioxidant defense leading to cell damage.

CONCLUSIONS

This study may contribute to a better understanding of redox homeostasis and its role in the development of diabetes and related vascular complications.