Glucose-induced Oxidative Stress Research Articles

Acteoside inhibits high glucose-induced oxidative stress injury in RPE cells and the outer retina through the Keap1/Nrf2/ARE pathway

Diabetes retinopathy (DR) is one of the most common microvascular complications of diabetes. Retinal pigment epithelial (RPE) cells exposed to a high glucose environment experience a series of functional damages, which is an important factor in promoting the progression of DR. Acteoside (ACT) has strong antioxidant and anti-apoptotic properties, but the mechanism of ACT in DR is not completely clear. Therefore, the purpose of the present study was to explore whether ACT inhibits the damage to RPE cells in a high glucose environment through antioxidative effects to alleviate the DR process. The DR in vitro cell model was constructed by treating RPE cells with high glucose, and the DR in vivo animal model was constructed by injecting streptozotocin (STZ) into the peritoneal cavity of mice to induce diabetes. The proliferation and apoptosis of RPE cells were detected by CCK-8 and flow cytometry assays, respectively. The expression changes in Nrf2, Keap1, NQO1 and HO-1 were evaluated by qRT‒PCR, Western blot and immunohistochemistry analyses. The MDA, SOD, GSH-Px and T-AOC contents were detected by kits. The changes in ROS and nuclear translocation of Nrf2 were observed by immunofluorescence assays. HE staining was used to measure the thickness of the outer nuclear layer (ONL) of the retina, and TUNEL staining was used to detect the number of apoptotic cells in the retinas of mice. In the present study, ACT effectively ameliorated outer retina damage in diabetic mice. In high glucose (HG)-induced RPE cells, ACT treatment had the following effects: improved proliferation, decreased apoptosis, inhibited Keap1 expression, promoted the nuclear translocation and expression of Nrf2, upregulated NQO1 and HO-1 (the target genes of Nrf2) expression, decreased ROS concentration, and increased the levels of the SOD, GSH-Px and T-AOC antioxidant indicators. However, knockdown of Nrf2 reversed the above phenomena, which indicated that the protective function of ACT in HG-induced RPE cells are closely related to Nrf2. In summary, the present study demonstrated that HG-induced oxidative stress injury is inhibited by ACT in RPE cells and the outer retina through the Keap1/Nrf2/ARE pathway.

Human umbilical cord-derived mesenchymal stem cells alleviate oxidative stress-induced islet impairment via the Nrf2/HO-1 axis.

Hyperglycaemia-induced oxidative stress may disrupt insulin secretion and β-cell survival in diabetes mellitus by overproducing reactive oxygen species. Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) exhibit antioxidant properties. However, the mechanisms by which hUC-MSCs protect β-cells from high glucose-induced oxidative stress remain underexplored. In this study, we showed that intravenously injected hUC-MSCs engrafted into the injured pancreas and promoted pancreatic β-cell function in a mouse model of type 1 diabetes mellitus. The in vitro study revealed that hUC-MSCs attenuated high glucose-induced oxidative stress and prevented β-cell impairment via the Nrf2/HO-1 signalling pathway. Nrf2 knockdown partially blocked the anti-oxidative effect of hUC-MSCs, resulting in β-cell decompensation in a high-glucose environment. Overall, these findings provide novel insights into how hUC-MSCs protect β-cells from high glucose-induced oxidative stress.

Corrigendum to: Betaine ameliorates high glucose-induced oxidative stress in granulosa cells.

In diabetes, abnormalities of granulosa cells (GCs) and steroidogenesis are associated with hyperglycaemia-induced oxidative stress. Betaine has beneficial effect in experimental model of diabetes by reducing oxidative stress, inflammation, and apoptosis. In this study we investigate the effects of betaine to prevent oxidative stress in GCs induced by high glucose and improve steroidogenesis. Primary GCs, isolated from ovarian follicles of C57BL/6 mice were cultured in 5mM (control) and 30mM (hyperglycaemia) of glucose and in presence of 5mM of betaine for 24h. Then antioxidant enzymes, malondialdehyde, oestradiol and progesterone were measured. In addition, the expression of Nrf2 and NF-κB , antioxidant enzymes (Sod1 , Gpx and Cat ) were analysed by qRT-PCR assay. We observed significant (P NF-κB and down-regulation of Nrf2 due to high concentration of glucose. Also significant (P Cat , Sod1 and GPx ) and activity reduction of these enzymes as well as significant (P NF-κB and up-regulating the expression of Nrf2 , Cat , Sod1 and GPx . It was also shown that betaine in the presence of FSH significantly (P Conclusion: Betaine compensated the antioxidant stress in mouse GCs under hyperglycaemic condition via regulation of Nrf2/NF-κB at transcription level. As betaine is a natural product and no side effect has been reported to today, we suggest more research needs to be carried out especially on patients whom suffer from diabetes to find the probability of using betaine as a therapeutic agent.

Cyp2e1 knockdown attenuates high glucose-induced apoptosis and oxidative stress of cardiomyocytes by activating PI3K/Akt signaling.

Cyp2e1 is a crucial CYP450 enzyme participating in diabetes and cardiovascular disorder. However, the role of Cyp2e1 in diabetic cardiomyopathy (DCM) has never been reported. Thus, we intended to identify the effects of Cyp2e1 on cardiomyocytes under high glucose (HG) conditions. Identification of differentially expressed genes in DCM and control rats was performed using bioinformatics analysis based on GEO database. The Cyp2e1-knockdown H9c2 and HL-1 cells were established through transfection with si-Cyp2e1. Western blot analysis was performed to determine the expression levels of Cyp2e1, apoptosis-related proteins and PI3K/Akt signaling-associated proteins. TUNEL assay was performed to assess apoptotic rate. Reactive oxygen species (ROS) generation was examined by DCFH2-DA staining assay. From the bioinformatics analysis, Cyp2e1 was confirmed as an upregulated gene in DCM tissues. In vitro assays proved that Cyp2e1 expression was markedly increased in HG-induced H9c2 and HL-1 cells. Cyp2e1 knockdown attenuated HG-induced apoptosis in both H9c2 and HL-1 cells, as proved by deceased apoptotic rate, relative cleaved caspase-3/caspase-3 level, and caspase-3 activity. Cyp2e1 knockdown reduced ROS generation and elevated the expression level of nuclear Nrf2 in HG-induced H9c2 and HL-1 cells. Increased relative levels of p-PI3K/PI3K and p-Akt/Akt were found in Cyp2e1-knockdown H9c2 and HL-1 cells. Inhibition of PI3K/Akt using LY294002 reversed the inhibitory effects of Cyp2e1 knockdown on cell apoptosis and ROS generation on cardiomyocytes. Cyp2e1 knockdown attenuated HG-induced apoptosis and oxidative stress by activating PI3K/Akt signaling in cardiomyocytes. These findings suggested that Cyp2e1 might be potentially used as an effective therapeutic strategy for DCM.

Circular RNA COL1A2 Mediates High Glucose-Induced Oxidative Stress and Pyroptosis by Regulating MiR-424-5p/SGK1 in Diabetic Nephropathy

Diabetic nephropathy (DN) represents a major diabetes-related complication, which could undermine renal function. CircCOL1A2 has been previously reported to show abnormal expression during DN. However, its functional role in the progression of DN, as well as the potential molecular mechanisms, remains unclear. The present work examined the expression of circCOL1A2 in the plasma of DN patients, and employed high glucose (HG)-challenged HK-2 cells as the in vitro cell model of hyperglycemia (HG)-induced DN. CircCOL1A2 was silenced using siRNA in HK-2 cells to clarify the functional engagement of circCOL1A2 in HG-induced DN. We examined the roles of circCOL1A2 in regulating oxidative stress by measuring reactive oxygen species (ROS), lipid peroxidation, and superoxide dismutase (SOD) levels. Besides, the effects of circCOL1A2 silencing on pyroptosis were investigated by RT-qPCR, western blot (WB), and ELISA assays. StarBase (version 2.0) was used to identify the downstream effector of circCOL1A2, and their interactions were further verified through dual-luciferase reporter analysis, RNA pull-down assays, and RNA immunoprecipitation (RIP) assay. CircCOL1A2 was highly expressed in DN patients and HG-induced HK-2 cells. Knocking down circCOL1A2 alleviated oxidative stress and pyroptosis upon HG treatment. In addition, we demonstrated that circCOL1A2 knockdown could promote miR-424-5p expression while inhibiting Serum/Glucocorticoid Regulated Kinase 1 (SGK1) level. Furthermore, miR-424-5p inhibitor or SGK1 overexpression impaired the effects of circCOL1A2 knockdown on HG-induced oxidative stress and pyroptosis. Hence, our results demonstrated that the circCOL1A2 mediates HG-exposed pyroptosis and oxidative stress through modulating miR-424-5p/SGK1 axis in diabetic nephropathy, indicating that silencing circCOL1A2 is a potential intervention strategy for DN management.

PD23-08 N-ACETYLCYSTEINE AMELIORATES HIGH GLUCOSE-INDUCED BLADDER DYSFUNCTION ASSOCIATED WITH METABOLIC SYNDROMES BY MEDIATING MITOCHONDRIAL FUNCTION AND THE ROS/NLRP3/NF-κB SIGNALING PATHWAYS

You have accessJournal of UrologyCME1 Apr 2023PD23-08 N-ACETYLCYSTEINE AMELIORATES HIGH GLUCOSE-INDUCED BLADDER DYSFUNCTION ASSOCIATED WITH METABOLIC SYNDROMES BY MEDIATING MITOCHONDRIAL FUNCTION AND THE ROS/NLRP3/NF-κB SIGNALING PATHWAYS Qiqi He, Junsheng Bao, Panfeng Shang, Li Yang, Zhiping Wang, and Sanjay Gupta Qiqi HeQiqi He More articles by this author , Junsheng BaoJunsheng Bao More articles by this author , Panfeng ShangPanfeng Shang More articles by this author , Li YangLi Yang More articles by this author , Zhiping WangZhiping Wang More articles by this author , and Sanjay GuptaSanjay Gupta More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003296.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We previously demonstrated that metabolic syndromes contribute to bladder dysfunction by altering the phenotype of bladder smooth muscles. We conducted this study to further examine the potential molecular mechanisms of metabolic syndromes (MS)-mediated bladder dysfunctions to facilitate diagnosis and therapeutic interventions. METHODS: In vitro, bladder muscle cells from C57BL/6N mice were cultured and divided into the control group, HG (45 MM) group, HG (45 MM)+NAC (5 MM) group, and HOS (50 MM) group. Oxidative stress, inflammation and fibrosis levels in BSMCs were observed by qRT‒PCR and Western blot analysis. Functional and morphological changes in mitochondria were examined. In vivo, forty SD rats (6 wks of age) were divided into four groups and bred until twenty weeks: control (CON), High Fat Diet (HFD), HFD+300 mg/kg/d NAC (HFD+LNAC), and HFD+900 mg/kg/d NAC (HFD+HNAC)}. At the end of the 20 weeks, blood and bladder smooth muscle samples were collected, and OS and contractile levels were examined. RESULTS: In vitro, high glucose significantly enhanced oxidative stress, inflammation and fibrosis in BSMCs. Moreover, the increase in cytokine expression was accompanied by enhanced NLRP3 expression and the phosphorylation of NF-κB. However, N-acetylcysteine had an inhibitory effect on the expression of ROS/NLRP3/NF-κB and the dissolution of mitochondria in HG-treated BSMCs. In vivo, compared to those in the control group, the mean contractility and frequency of bladder smooth muscles in the HFD group was significantly decreased (p<0.01). The mean contractility in the LNAC+HFD group was significantly higher than that in the HFD group (p<0.01). Interestingly, the HNAC+HFD group did not show any recovery in muscle contractility but exhibited significantly reduced bladder contractile frequency (p<0.01). CONCLUSIONS: Our findings indicated that high glucose-induced oxidative stress, inflammation and fibrosis are mainly mediated by the ROS/NLRP3/NF-κB signaling pathways and mitochondrial changes in BSMCs. NAC ameliorated these changes by blocking the ROS/NLRP3/NF-κB signaling pathways and protecting mitochondrial function and morphology. Source of Funding: National Natural Science Foundation of China ( 81800671), Cuiyin Talent Program (CY2021-MS-A02) © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e674 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Qiqi He More articles by this author Junsheng Bao More articles by this author Panfeng Shang More articles by this author Li Yang More articles by this author Zhiping Wang More articles by this author Sanjay Gupta More articles by this author Expand All Advertisement PDF downloadLoading ...

Decreasing REDD1 expression protects against high glucose-induced apoptosis, oxidative stress and inflammatory injury in podocytes through regulation of the AKT/GSK-3β/Nrf2 pathway

Objective Our goal in this work was to investigate the possible role and mechanism of regulated in development and DNA damage response 1 (REDD1) in mediating high glucose (HG)-induced podocyte injury in vitro. Materials and methods Mouse podocytes were stimulated with HG to establish HG injury model. Protein expression was examined by Western blotting. Cell viability was measured by cell counting kit-8 assay. Cell apoptosis was assessed by annexin V‐FITC/propidium iodide and TUNEL apoptotic assays. Levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were quantified by commercial kits. Concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β were measured by ELISA. Results A marked increase in REDD1 expression was observed in podocytes stimulated with HG. Reduced REDD1 expression strikingly restrained HG-induced increases in apoptosis, oxidative stress, and inflammation response in cultured podocytes. Decreasing REDD1 expression enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) activation in HG-exposed podocytes via regulation of the AKT/glycogen synthase kinase-3 beta (GSK-3β) pathway. Inhibition of AKT or reactivation of GSK-3β prominently abolished Nrf2 activation induced by decreasing REDD1 expression. Pharmacological repression of Nrf2 markedly reversed the protective effects of decreasing REDD1 expression in HG-injured podocytes. Conclusion Our data demonstrate that decreasing REDD1 expression protects cultured podocytes from HG-induced injuries by potentiating Nrf2 signaling through regulation of the AKT/GSK-3β pathway. Our work underscores the potential role of REDD1-mediated podocyte injury during the development of diabetic kidney disease.

Never in mitosis gene A-related kinase-6 deficiency deteriorates diabetic cardiomyopathy via regulating heat shock protein 72.

NIMA (never in mitosis, gene A)-related kinase-6 (NEK6), a cell cycle regulatory gene, was found to regulate cardiac hypertrophy. However, its role in diabetes-induced cardiomyopathy has not been fully elucidated. This research was designed to illustrate the effect of NEK6 involved in diabetic cardiomyopathy. Here we used a streptozotocin (STZ)-induced mice diabetic cardiomyopathy model and NEK6 knockout mice to explore the role and mechanism of NEK6 in diabetic-induced cardiomyopathy. NEK6 knockout mice and wild-type littermates were subjected to STZ injection (50mg/kg/day for 5days) to induce a diabetic cardiomyopathy model. As a result, 4months after final STZ injection, DCM mice revealed cardiac hypertrophy, fibrosis, and systolic and diastolic dysfunction. NEK6 deficiency causes deteriorated cardiac hypertrophy, fibrosis, and cardiac dysfunction. Furthermore, we observed inflammation and oxidative stress in the hearts of NEK6 deficiency mice under diabetic cardiomyopathy pathology. Adenovirus was used to upregulate NEK6 in neonatal rat cardiomyocytes, and it was found that NEK6 ameliorated high glucose-induced inflammation and oxidative stress. Our findings revealed that NEK6 increased the phosphorylation of heat shock protein 72 (HSP72) and increased the protein level of PGC-1α and NRF2. Co-IP assay experiment confirmed that NEK6 interacted with HSP72. When HSP72 was silenced, the anti-inflammation and anti-oxidative stress effects of NEK6 were blurred. In summary, NEK6 may protect diabetic-induced cardiomyopathy by interacting with HSP72 and promoting the HSP72/PGC-1α/NRF2 signaling. KEY MESSAGES: NEK6 knockout deteriorated cardiac dysfunction, cardiac hypertrophy, fibrosis as well as inflammation response, and oxidative stress. NEK6 overexpression attenuated high glucose induced inflammation and oxidative stress. The underlying mechanisms of the protective role of NEK6 in the development of diabetic cardiomyopathy seem to involve the regulation of HSP72-NRF2- PGC-1α pathway. NEK6 may become a new therapeutic target for diabetic cardiomyopathy.

Resveratrol alleviates high glucose-induced oxidative stress and apoptosis in rat cardiac microvascular endothelial cell through AMPK/Sirt1 activation

Diabetic cardiomyopathy (DCM) is a common complication of diabetes. DCM causes extensive lesions on cardiac microvasculature that is predominantly cardiac microvascular endothelial cells (CMECs). Reducing high glucose (HG)-induced damage such as oxidative damage and apoptosis could alleviate the development of DCM. The natural polyphenol resveratrol (RSV) is widely suggested as a cardioprotective agent that protect against DCM. However, limited evidence supports the protection of RSV against oxidative damage and apoptosis and study on the direct effects of RSV in CMEC is missing. Therefore, the current paper aimed to illustrate if RSV could attenuate oxidative stress and apoptosis in CMEC and to investigate the underlying mechanisms. Our data showed that HG elevated reactive oxygen species, malondialdehyde, decreased superoxide dismutase activity, increased apoptotic cell percentage in CMEC, which were reversed by RSV administration. In addition, RSV demonstrated antioxidative and anti-apoptotic effects in CMEC through AMPK/Sirt1 activation, further confirmed by AMPK inhibition or Sirt1 silencing. This study provides new evidence to support RSV as a potential cardioprotective alternative in treating DCM.

Betaine ameliorates high glucose-induced oxidative stress in granulosa cells.

In diabetes, abnormalities of granulosa cells (GCs) and steroidogenesis are associated with hyperglycaemia-induced oxidative stress. Betaine has beneficial effect in experimental model of diabetes by reducing oxidative stress, inflammation, and apoptosis. In this study we investigate the effects of betaine to prevent oxidative stress in GCs induced by high glucose and improve steroidogenesis. Primary GCs, isolated from ovarian follicles of C57BL/6 mice were cultured in 5mM (control) and 30mM (hyperglycaemia) of glucose and in presence of 5mM of betaine for 24h. Then antioxidant enzymes, malondialdehyde, oestradiol and progesterone were measured. In addition, the expression of Nrf2 and NF-κB , antioxidant enzymes (Sod1 , Gpx and Cat ) were analysed by qRT-PCR assay. We observed significant (P <0.001) up-regulation of NF-κB and down-regulation of Nrf2 due to high concentration of glucose. Also significant (P <0.001) down-regulation of related antioxidant genes (Cat , Sod1 and GPx ) and activity reduction of these enzymes as well as significant (P <0.001) elevation of malondialdehyde was observed. In addition, betaine treatment compensated the drastic effect of high glucose induced oxidative stress via down-regulating the expression of NF-κB and up-regulating the expression of Nrf2 , Cat , Sod1 and GPx . It was also shown that betaine in the presence of FSH significantly (P <0.001) restored the oestradiol and progesterone level. Betaine compensated the antioxidant stress in mouse GCs under hyperglycaemic condition via regulation of Nrf2/NF-κB at transcription level. As betaine is a natural product and no side effect has been reported to today, we suggest more research needs to be carried out especially on patients whom suffer from diabetes to find the probability of using betaine as a therapeutic agent.

Protective Effects of Xanthohumol against Diabetic Nephropathy in a Mouse Model

Introduction: Diabetic nephropathy (DN) is a long-term loss of renal function occurring in the diabetic patients, leading to 5 million deaths in 2015, and this number is dramatically growing annually. Due to unsatisfied outcome of current treatment, there is urgent need to develop more effective therapeutic drugs for DN. Methods: Approximately 150 kinds of natural small molecule drugs that have been used on the market or in the clinical trials in the presence of high glucose were tested individually on the same batch of human renal glomerular endothelial cells (GECs) and human kidney 2 (HK-2) cells with triplicated wells by using a robotic pipetting workstation to screen for the potential drug candidate. Cell viability and oxidative stress were examined in the GECs and HK-2 cells. DN mouse model was established and treated with 25 mg/kg xanthohumol. Results: By measuring cell viability, xanthohumol was selected as our predicted drug candidate for DN because it could mostly protect renal cells from high glucose with about 90% survived GECs and HK-2 cells, about 2.12- and 2.37-fold increase compared to glucose group which was with 42.78% and 37.69% survived GECs and HK-2 cells, respectively. Then, xanthohumol inhibited high glucose-induced oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in vitro. Moreover, xanthohumol (25 mg/kg) significantly decreased the levels of serum creatinine, blood urea nitrogen, urea protein, and kidney weight/body weight ratio in DN mice. In addition, the increase of reactive oxygen species production and the decrease of superoxide dismutase and catalase activities in DN mice were partially reversed by xanthohumol. mRNA levels of Nrf2, Hmox1, and Nqol genes were all decreased by xanthohumol DN mice. Conclusion: Xanthohumol could ameliorate DN-related impairments via Nrf2 signaling pathway, which might serve as a promising drug candidate for treatment of DN.

Xanthine Oxidase Inhibition Ameliorates High Glucose-Induced Oxidative Stress by Activating AMPK Through the Purine Salvage Pathway in Glomerular Endothelial Cells

Xanthine Oxidase Inhibition Ameliorates High Glucose-Induced Oxidative Stress by Activating AMPK Through the Purine Salvage Pathway in Glomerular Endothelial Cells

Swinhoeic acid from Potentilla fragarioides ameliorates high glucose-induced oxidative stress and accumulation of ECM in mesangial cells via Keap1-dependent activation of Nrf2

ABSTRACT Objectives Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes mellitus. Oxidative stress resulting from high glucose promotes accumulation of ECM and development of DN. Activation of Nrf2 could attenuate oxidative stress and following accumulation of ECM. To find novel therapy for DN, we explored the effects of swinhoeic acid from Potentilla fragarioides on mesangial cells under high glucose and underlying mechanisms. Methods CCK-8 and BrdU incorporation assays for survival of mesangial cells gave the concentration of swinhoeic acid in following investigations. ROS, MDA, SOD and CAT were determined. And ECM proteins and their upstream regulators TGF-β1 and CTGF were detected using ELISA assays. Activation of Nrf2 was explored by immunofluorescence staining together with luciferase reporter assay. To demonstrate the role of Nrf2 activation, siRNA interference was performed. And co-immunoprecipitation assay was used to elucidate swinhoeic acid affects the interaction between Keap1 and Nrf2. Results Swinhoeic acid at 10 and 20 μM attenuated oxidative stress and accumulation of ECM in mesangial cells under high glucose. Itactivated Nrf2 in a Keap1-dependent manner, which was involved in its effects. Conclusion Swinhoeic acid ameliorates oxidative stress and accumulation of ECM resulting from high glucose in mesangial cells via activating Nrf2 in Keap1-dependent manner.

Ganoderic Acid A Inhibits High Glucose-Induced Oxidative Stress and Extracellular Matrix Accumulation in Rat Glomerular Mesangial Cells.

Objective We aimed to investigate the role of ganoderic acid A (GAA) in glomerular mesangial cells (GMCs) under high glucose (HG). Methods GMCs were pretreated with GAA and then cultured under HG condition for 24 h. Cell proliferation was measured by CCK-8 assay. The production of intracellular ROS was determined using DCFH-DA. The activities of SOD and CAT were measured using ELISA kits. The expressions of NOX2, NOX4, fibronectin (FN), collagen IV (col IV), p38, and p-p38 were detected by western blot. Results GAA suppressed GMC proliferation in response to HG stimulation. GAA significantly attenuated HG-caused increase in ROS production and decreases in SOD and CAT activities in GMCs. In addition, the increased expressions of NOX2 and NOX4 and NOX activity in HG-induced GMCs were significantly decreased by GAA. Furthermore, GAA greatly inhibited the levels of FN and col IV in HG-stimulated GMCs. Mechanistic investigations showed that HG caused activation of p38 MAPK pathway, whereas the induction was mitigated by GAA. Notably, the specific agonist of p38 MAPK pathway (P79350) reversed the effects of GAA on GMCs. Conclusion GAA protected GMCs from HG-induced oxidative stress and ECM production, which was mediated by the inhibition of the p38 MAPK pathway.

Norkurarinone and isoxanthohumol inhibit high glucose and hypoxia-induced angiogenesis via improving oxidative stress and regulating autophagy in human retinal microvascular endothelial cells

Diabetic retinopathy (DR) is one of the most serious complications of diabetic microangiopathy. Recent studies have shown its close association with high glucose-induced oxidative stress and autophagy disorder. Previous studies showed that various compounds of flavonoids of Sophora flavescens Aiton extracted using ethyl acetate (SFE) could cross the blood-retinal barrier, exerting favorable effects on retinal tissue disorders and angiogenesis in rats with DR. However, the mechanism and the specific material basis for SFE are still unclear. Here, we established the in vitro DR model of human retinal microvascular endothelial cell (HRMECs) induced by high glucose and hypoxia (HGY), screened out the potential pharmacodynamic components of SFE viz. norkurarinone (NKR) and isoxanthohumol (IXM), and proved that they could improve the pathological features of angiogenesis. Further, we explored the mechanism of action of NKR and IXM, investigating their effects on cellular oxidative stress and autophagy levels under HGY conditions. Finally, the role of the PI3K/AKT/mTOR signaling pathway in the regulation of cell autophagy by NKR and IXM was evaluated. Collectively, NKR and IXM could improve cellular oxidative stress state and activate PI3K/AKT/mTOR signaling pathway to regulate autophagy dysregulation, thus playing a significant role in protecting HRMECs from HGY-caused angiogenesis.

Terpenoids from the Seeds of Toona sinensis and Their Ability to Attenuate High Glucose-Induced Oxidative Stress and Inflammation in Rat Glomerular Mesangial Cells.

Toona sinensis (A. Juss.) Roem is an edible medicinal plant that belongs to the genus Toona within the Meliaceae family. It has been confirmed to display a wide variety of biological activities. During our continuous search for active constituents from the seeds of T. sinensis, two new acyclic diterpenoids (1–2), together with five known limonoid-type triterpenoids (3–7), five known apotirucallane-type triterpenoids (8–12), and three known cycloartane-type triterpenoids (13–15), were isolated and characterized. Their structures were identified based on extensive spectroscopic experiments, including nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectra (HR-ESI-MS), and electronic circular dichroism (ECD), as well as the comparison with those reported in the literature. We compared these findings to those reported in the literature. Compounds 5, 8, and 13–14 were isolated from the genus Toona, and compounds 11 and 15 were obtained from T. sinensis for the first time. The antidiabetic nephropathy effects of isolated compounds against high glucose-induced oxidative stress and inflammation in rat glomerular mesangial cells (GMCs) were assessed in vitro. The results showed that new compounds 1 and 2 could significantly increase the levels of Nrf-2/HO-1 and reduce the levels of NF-κB, TNF-α, and IL-6 at concentrations of 30 μM. These results suggest that compounds 1 and 2 might prevent the occurrence and development of diabetic nephropathy (DN) and facilitate the research and development of new antioxidant and anti-inflammatory drugs suitable for the prevention and treatment of DN.

Carvacrol protects the ARPE19 retinal pigment epithelial cells against high glucose-induced oxidative stress, apoptosis, and inflammation by suppressing the TRPM2 channel signaling pathways.

The concentration of plasma high glucose (HGu) in diabetes mellitus (DM) induces the retinal pigment epithelial cell (ARPE19) death via the increase of inflammation, cytosolic (cytROS), and mitochondrial (mitROS) free oxygen radical generations. Transient potential melastatin 2 (TRPM2) cation channel is stimulated by cytROS and mitROS. Hence, the cytROS and mitROS-mediated excessive Ca2+ influxes via the stimulation of TRPM2 channel cause to the induction of DM-mediated retina oxidative cytotoxicity. Because of the antioxidant role of carvacrol (CRV), it may modulate oxidative cytotoxicity via the attenuation of TRPM2 in the ARPE19. We aimed to investigate the modulator action of CRV treatment on the HGu-mediated TRPM2 stimulation, oxidative stress, and apoptosis in the ARPE19 cell model. The ARPE19 cells were divided into four groups as normal glucose (NGu), NGu + Carv, HGu, and HGu + CRV. The levels of cell death (propidium iodide/Hoechst rate) and apoptosis markers (caspases 3, 8, and 9), cytokine generations (IL-1β and TNF-α), ROS productions (cytROS, mitROS, and lipid peroxidation), TRPM2 currents, and intracellular free Ca2+ (Fluo/3) were increased in the HGu group after the stimulations of hydrogen peroxide and ADP-ribose, although their levels were diminished via upregulation of glutathione and glutathione peroxidase by the treatments of CRV and TRPM2 blockers. Current results confirmed that the HGu-induced overload Ca2+ influx and oxidative retinal toxicity in the ARPE19 cellswere induced by the stimulation of TRPM2, although they were modulated via the inhibition of TRPM2 by CRV. CRV may be noted as a potential therapeutic antioxidant to the TRPM2 activation-mediated retinal oxidative injury.

Anti-Hyperglycemic Effect of Magnesium-Enhanced Alkaline-Reduced Water on High Glucose-Induced Oxidative Stress in Renal Tubular Epithelial Cells

Diabetes is coupled with hyperglycemia, a state in which elevated glucose levels trigger oxidative stress (OS) in various body functions. One of the organs most afflicted by diabetes is the kidney. Despite this, specific treatments to mitigate the harmful effects of hyperglycemia-induced OS in the kidney have not been extensively explored. This study evaluates the anti-hyperglycemic efficacy of magnesium-enhanced alkaline-reduced water (MARW) in human kidney-2 (HK-2) cells. OS, mitogen-activated protein kinase (MAPK) signaling and fibrosis markers were assessed in high glucose (HG)-induced HK-2 cells, followed by treatment with experimental water for 24 h. Surprisingly, MARW rescued the vitality of HG-induced HK-2 cells, in contrast to that seen with other experimental waters. Additionally, MARW maintained reactive oxygen species, nitric oxide, catalase, glutathione peroxidase, hepatocyte growth factor and glucose uptake in HG-induced HK-2 cells but not in tap water and mineral water. Similarly, MARW downregulated the expression of MAPK and fibrosis-linked signaling proteins such as p-p38, phospho-c-Jun N-terminal kinase, α-smooth muscle actin, matrix metalloproteinase-3 and cleaved caspase 3 in HG-induced HK-2 cells. In conclusion, MARW protects HK-2 cells from the deleterious effects of HG by stabilizing antioxidant defenses and by signaling cascades related to metabolism, apoptosis and fibrosis.

Knockdown of ILK Alleviates High Glucose-Induced Damage of H9C2 Cells through TLR4/MyD88/NF-κB Pathway.

The aim of this study was to explore the role of ILK in an in vitro model of diabetic cardiomyopathy. We used 30 mmol/L high glucose to treat H9C2 cells to construct an in vitro model, knocked down the ILK expression level of H9C2 cells by small interference technology, and detected the activity of antioxidant enzymes and inflammatory factors in the supernatant. The expression levels of SOD1 and IL-1β were detected by immunofluorescence staining. The expression levels of the TLR4/MyD88/NF-κB signaling pathway and its downstream factors were detected by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Compared with the control group, after high-glucose culture of H9C2 cells, the cell activity decreased, while the apoptosis rate increased, with the TLR4/MyD88/NF-κB signaling pathway activated, thereby inducing oxidative stress and inflammation. Compared with the high-glucose group, the HG+si-ILK group increased cell activity, decreased the apoptosis rate, and inhibited the excessive activation of the TLR4/MyD88/NF-κB signaling pathway, thereby improving oxidative stress and inflammation. Knockdown of ILK expression can protect H9C2 cells from reducing high glucose-induced inflammation, oxidative stress, and apoptosis by inhibiting the TLR4/MyD88/NF-κB signaling pathway.

Folate derivatives, 5-methyltetrahydrofolate and 10-formyltetrahydrofolate, protect BEAS-2B cells from high glucose-induced oxidative stress and inflammation.

Folate (vitamin B9) and its biologically active derivatives are well-known antioxidant molecules protecting cells from oxidative degradation. The presence of high glucose, often found in diabetic patients, causes oxidative stress resulting in cellular stress and inflammatory injury. Cells in organs such as the lung are highly prone to inflammation, and various protective mechanisms exist to prevent the progressive disorders arising from inflammation. In the present study, the synthetic form of folate, i.e. folic acid, and active forms of folate, i.e. 5-methyltetrahydrofolate and 10-formyltetrahydrofolate, were evaluated for their antioxidant and antiinflammatory potential against high glucose (50 mM)–mediated oxidative stress and inflammation in BEAS-2B cells, an immortalised bronchial epithelial cell line. High glucose treatment showed a 67% reduction in the viability of BEAS-2B cells, which was restored to the viability levels seen in control cultures by the addition of active folate derivatives to the culture media. The DCFH-DA fluorometric assay was performed for oxidative stress detection. The high glucose–treated cells showed a significantly higher fluorescence intensity (1.81- and 3.8-fold for microplate assay and microscopic observation, respectively), which was normalised to control levels on supplementation with active folate derivatives. The proinflammatory NF-κB p50 protein expression in the active folate derivative–supplemented high glucose–treated cells was significantly lower compared to the folic acid treatment. In support of these findings, in silico microarray GENVESTIGATOR database analysis showed that in bronchiolar small airway epithelial cells exposed to inflammatory condition, folate utilization pathway genes are largely downregulated. However, the folate-binding protein gene, which encodes to the folate receptor 1 (FOLR1), is significantly upregulated, suggesting a high demand for folate by these cells in inflammatory situations. Supplementation of the active folate derivatives 5-methyltetrahydrofolate and 10-formyltetrahydrofolate resulted in significantly higher protection over the folic acid from high glucose–induced oxidative stress and inflammation. Therefore, the biologically active folate derivatives could be a suitable alternative over the folic acid for alleviating inflammatory injury-causing oxidative stress.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11626-022-00691-w.