Hyperglycemia Induces Generation of Reactive Oxygen Species and Accelerates Apoptotic Cell Death in Salivary Gland Cells

Pathobiology ◽  
2021 ◽  
pp. 1-8
Author(s):  
Naoyuki Matsumoto ◽  
Daisuke Omagari ◽  
Ryoko Ushikoshi-Nakayama ◽  
Tomoe Yamazaki ◽  
Hiroko Inoue ◽  
...  

<b><i>Introduction:</i></b> Type-2 diabetes mellitus (T2DM) is associated with several systemic vascular symptoms and xerostomia. It is considered that hyperglycemia-induced polyuria and dehydration cause decreased body-water volume, leading to decreased saliva secretion and, ultimately, xerostomia. In T2DM, increased production of reactive oxygen species (ROS) causes tissue damage to vascular endothelial cells as well as epithelial tissue, including pancreas and cornea. Hence, a similar phenomenon may occur in other tissues and glands in a hyperglycemic environment. <b><i>Methods:</i></b> Salivary gland tissue injury was examined, using T2DM model mouse (db/db). Transferase‐mediated dUTP nick‐end labeling (TUNEL) was conducted to evaluate tissue injury. The levels of malondialdehyde (MDA) and 8-hydroxy-2′-deoxyguanosine, Bax/Bcl-2 ratio were measured as indicator of oxidative stress. Moreover, in vitro ROS production and cell injury was evaluated by mouse salivary gland-derived normal cells under high-glucose condition culture. <b><i>Results:</i></b> In vivo and in vitro analysis showed a higher percentage of TUNEL-positive cells and higher levels of MDA and 8-hydroxy-2′-deoxyguanosine in salivary gland tissue of db/db mice. This suggests damage of saliva secretion-associated lipids and DNA by hyperglycemic-induced oxidative stress. To analyze the mechanism by which hyperglycemia promotes ROS production, mouse salivary gland-derived cells were isolated. The cell culture with high-glucose medium enhanced ROS production and promotes apoptotic and necrotic cell death. <b><i>Conclusion:</i></b> These findings suggest a novel mechanism whereby hyperglycemic-induced ROS production promotes salivary gland injury, resulting in hyposalivation.

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Yin-Yin Chen ◽  
Han Hong ◽  
Yu-Ting Lei ◽  
Jia Zou ◽  
Yi-Ya Yang ◽  
...  

Abstract Background Obesity-related nephropathy (ORN) has become one of the leading causes of end-stage renal disease and has tripled over the past decade. Previous studies have demonstrated that decreased reactive oxygen species production may contribute to improving ORN by ameliorating oxidative stress injury. Here, IκB kinase (IKK) was hypothesized to inactivate the deubiquitination activity of cylindromatosis (CYLD) by activating the phosphorylation of CYLD, thus promoting the ubiquitination of NF-E2-related factor 2 (Nrf2) and further aggravating oxidative stress injury of the kidney in ORN. This study was aimed to confirm this hypothesis. Methods Haematoxylin and eosin (HE), periodic acid-Schiff (PAS) and Oil Red O staining were performed to assess histopathology. Dihydroethidium (DHE) staining and MDA, SOD, CAT, and GSH-PX assessments were performed to measure reactive oxygen species (ROS) production. Immunohistochemical (IHC) staining, qRT–PCR and/or western blotting were performed to assess the expression of related genes. JC-1 assays were used to measure the mitochondrial membrane potential (ΔΨm) of treated HK-2 cells. Co-immunoprecipitation experiments (Co-IP) were used to analyse the interaction between CYLD and Nrf2 in ORN. Results ORN in vivo and in vitro models were successfully constructed, and oxidative stress injury was detected in the model tissues and cells. Compared with the control groups, the phosphorylation level of CYLD increased while Nrf2 levels decreased in ORN model cells. An IKK inhibitor reduced lipid deposition, ROS production, CYLD phosphorylation levels and ΔΨm in vitro, which were reversed by knockdown of CYLD. Nrf2 directly bound to CYLD and was ubiquitinated in ORN cells. The proteasome inhibitor MG132 activated the Nrf2/ARE signalling pathway, thereby reversing the promoting effect of CYLD knockdown on oxidative stress. Conclusion IKK inactivates the deubiquitination activity of CYLD by activating the phosphorylation of CYLD, thus promoting the ubiquitination of Nrf2 and further aggravating oxidative stress injury of the kidney in ORN. This observation provided a feasible basis for the treatment of kidney damage caused by ORN.


2021 ◽  
Vol 22 (23) ◽  
pp. 12899
Author(s):  
Yutong Jin ◽  
Brian Dixon ◽  
Lyndon Jones ◽  
Maud Gorbet

A large number of polymorphonuclear neutrophils (PMNs) invade the ocular surface during prolonged eye closure (sleep); these leukocytes are commonly referred as tear PMNs. PMNs contribute to homeostasis and possess an arsenal of inflammatory mediators to protect against pathogens and foreign materials. This study examined the ability of tear PMNs to generate reactive oxygen species (ROS), an essential killing mechanism for PMNs which can lead to oxidative stress and imbalance. Cells were collected after sleep from healthy participants using a gentle eye wash. ROS production in stimulated (phorbol-12-myristate-13-acetate (PMA), lipopolysaccharides (LPS) or N-Formylmethionyl-leucyl-phenylalanine (fMLP)) and unstimulated tear PMNs was measured using luminol-enhanced chemiluminescence for 60 min. A high level of constitutive/spontaneous ROS production was observed in tear PMNs in the absence of any stimulus. While tear PMNs were able to produce ROS in response to PMA, they failed to appropriately respond to LPS and fMLP, although fMLP-stimulated tear PMNs generated ROS extracellularly in the first three minutes. Higher ROS generation was observed in isolated tear PMNs which may be due to priming from the magnetic bead cell separation system. The differential responses of tear PMNs in ROS generation provide further evidence of their potential inflammatory roles in ocular complications involving oxidative stress.


Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 233
Author(s):  
Tasuku Konno ◽  
Eduardo Pinho Melo ◽  
Joseph E. Chambers ◽  
Edward Avezov

Reactive oxygen species (ROS) are produced continuously throughout the cell as products of various redox reactions. Yet these products function as important signal messengers, acting through oxidation of specific target factors. Whilst excess ROS production has the potential to induce oxidative stress, physiological roles of ROS are supported by a spatiotemporal equilibrium between ROS producers and scavengers such as antioxidative enzymes. In the endoplasmic reticulum (ER), hydrogen peroxide (H2O2), a non-radical ROS, is produced through the process of oxidative folding. Utilisation and dysregulation of H2O2, in particular that generated in the ER, affects not only cellular homeostasis but also the longevity of organisms. ROS dysregulation has been implicated in various pathologies including dementia and other neurodegenerative diseases, sanctioning a field of research that strives to better understand cell-intrinsic ROS production. Here we review the organelle-specific ROS-generating and consuming pathways, providing evidence that the ER is a major contributing source of potentially pathologic ROS.


2017 ◽  
Vol 44 (4) ◽  
pp. 288-293 ◽  
Author(s):  
Shiho Yamadera ◽  
Yuya Nakamura ◽  
Masahiro Inagaki ◽  
Isao Ohsawa ◽  
Hiromichi Gotoh ◽  
...  

Aim: To examine the effects of vitamin E-coated dialyzer on oxidative stress in vitro. Methods: A dialyzer with a synthetic polymer membrane (APS-11SA) and vitamin E-coated dialyzer (VPS-11SA) were connected to a blood tubing line, and U937 cells were circulated in the device. The circulating fluid was collected at 1, 2, 5, 10, 25, and 50 cycles, which are estimated numbers of passes through the dialyzer. Intracellular reactive oxygen species (ROS) production, malondialdehyde (MDA), and Cu/Zn-superoxide dismutase (SOD) were quantified. Results: Intracellular ROS production was increased in the first cycle by APS-11SA and was decreased throughout the experiment by VPS-11SA. Intracellular ROS production in the VPS-11SA device was lower, and MDA levels were decreased. MDA levels were lower during VPS-11SA processing than during APS-11SA processing. Cu/Zn-SOD levels remained unchanged. Conclusion: Our results highlight anti-oxidative-stress effects of a vitamin E-coated dialyzer.


2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Sunil Joshi ◽  
Ammon B. Peck ◽  
Saeed R. Khan

A major role of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes is to catalyze the production of superoxides and other reactive oxygen species (ROS). These ROS, in turn, play a key role as messengers in cell signal transduction and cell cycling, but when they are produced in excess they can lead to oxidative stress (OS). Oxidative stress in the kidneys is now considered a major cause of renal injury and inflammation, giving rise to a variety of pathological disorders. In this review, we discuss the putative role of oxalate in producing oxidative stress via the production of reactive oxygen species by isoforms of NADPH oxidases expressed in different cellular locations of the kidneys. Most renal cells produce ROS, and recent data indicate a direct correlation between upregulated gene expressions of NADPH oxidase, ROS, and inflammation. Renal tissue expression of multiple NADPH oxidase isoforms most likely will impact the future use of different antioxidants and NADPH oxidase inhibitors to minimize OS and renal tissue injury in hyperoxaluria-induced kidney stone disease.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yongpan Huang ◽  
Xinliang Li ◽  
Xi Zhang ◽  
Jiayu Tang

Oxymatrine (OMT) is the major quinolizidine alkaloid extracted from the root of Sophora flavescens Ait and has been shown to exhibit a diverse range of pharmacological properties. The aim of the present study was to investigate the role of OMT in diabetic brain injury in vivo and in vitro. Diabetic rats were induced by intraperitoneal injection of a single dose of 65 mg/kg streptozotocin (STZ) and fed a high-fat and high-cholesterol diet. Memory function was assessed using a Morris water maze test. A SH-SY5Y cell injury model was induced by incubation with glucose (30 mM/l) to simulate damage in vitro. The serum fasting blood glucose, insulin, serum S100B, malondialdehyde (MDA), and superoxide dismutase (SOD) levels were analyzed using commercial kits. Morphological changes were observed using Nissl staining and electron microscopy. Cell apoptosis was assessed using Hoechst staining and TUNEL staining. NADPH oxidase (NOX) and caspase-3 activities were determined. The effects of NOX2 and NOX4 knockdown were assessed using small interfering RNA. The expression levels of NOX1, NOX2, and NOX4 were detected using reverse transcription-quantitative PCR and western blotting, and the levels of caspase-3 were detected using western blotting. The diabetic rats exhibited significantly increased plasma glucose, insulin, reactive oxygen species (ROS), S-100B, and MDA levels and decreased SOD levels. Memory function was determined by assessing the percentage of time spent in the target quadrant, the number of times the platform was crossed, escape latency, and mean path length and was found to be significantly reduced in the diabetic rats. Hyperglycemia resulted in notable brain injury, including histological changes and apoptosis in the cortex and hippocampus. The expression levels of NOX2 and NOX4 were significantly upregulated at the protein and mRNA levels, and NOX1 expression was not altered in the diabetic rats. NOX and caspase-3 activities were increased, and caspase-3 expression was upregulated in the brain tissue of diabetic rats. OMT treatment dose-dependently reversed behavioral, biochemical, and molecular changes in the diabetic rats. In vitro, high glucose resulted in increases in reactive oxygen species (ROS), MDA levels, apoptosis, and the expressions of NOX2, NOX4, and caspase-3. siRNA-mediated knockdown of NOX2 and NOX4 decreased NOX2 and NOX4 expression levels, respectively, and reduced ROS levels and apoptosis. The results of the present study suggest that OMT alleviates diabetes-associated cognitive decline, oxidative stress, and apoptosis via NOX2 and NOX4 inhibition.


2007 ◽  
Vol 19 (1) ◽  
pp. 208
Author(s):  
N. W. K. Karja ◽  
K. Kikuchi ◽  
M. Ozawa ◽  
M. Fahrudin ◽  
T. Somfai ◽  
...  

Nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase), an enzyme required to catalyze the oxidation of NADPH to NADP during the metabolism of glucose via the pentose phosphate pathway (PPP), was considered as contributing to intracellular reactive oxygen species (ROS) production. Production of superoxide anion and H2O2 via NADPH oxidase has been reported on a rabbit blastocyst surface (Manes and Lai 1995 J. Reprod. Fertil. 104, 69–75). The objective of this study was to examine the effects on in vitro development and intracellular ROS content after the addition of diphenyleneiodonium (DPI), an inhibitor of NADPH oxidase, or dehydroepiandrosterone (DHEA), an inhibitor of glucose-6-phosphate dehydrogenase (G6PDH), to culture medium during the early embryonic development of in vitro-produced (IVP) porcine embryos. To confirm that these inhibitors lead to reduction in NADPH concentration in the embryo and hence likely to be inhibiting the PPP, a brilliant cresyl blue (BCB) test was performed on Day 2 (the day of insemination = Day 0) of culture. Porcine cumulus–oocyte complexes were matured and fertilized in vitro as described previously (Kikuchi et al. 2002 Biol. Reprod. 66, 1033–1041). Prezumptive zygotes were then cultured in NCSU-37 supplemented with 5.5 mM glucose and DPI at concentrations of 0.5 or 1 nM or DHEA at concentrations of 10 or 100 �M (DPI-0.5, DPI-1, DHEA-10 and DHEA-100 groups, respectively) from Day 0 to Day 2 of culture. All of the embryos were cultured subsequently until Day 6 in NCSU-37 supplemented with only 5.5 mM glucose. Data were analyzed by ANOVA. On Day 6, the development to the blastocyst stage of embryos in DPI-0.5, DPI-1, DHEA-10, and DHEA-100 groups were 16.1, 17.6, 16.1, and 19.5%, respectively, which were not significantly different from that of the control group (17.5%) (n d 165 per group, 5 replicates). However, the mean cell number in blastocysts derived from DPI-1, DHEA-10, and DHEA-100 groups (40.8 � 2.3, 39.3 � 1.7, and 42.5 � 2.7, respectively) was significantly higher (P &lt; 0.01) than those in the control (33.4 � 1.6) and DPI-0.5 (32.7 � 1.6) groups. At 20 min after an exposure to BCB, the percentage of BCB+ embryos in DPI-1, DHEA-10, and DHEA-100 groups (73.8, 79.9, and 77.8%, respectively) were significantly higher (P &lt; 0.01) than those in the control and DPI-0.5 groups (42% and 53.9%, respectively) (n = 81-92 per group, 6 replicates), indicating that these two inhibitors effectively induce the reduction of NADPH concentration in the embryos. Moreover, the addition of DPI at 1 nM or DHEA at 10 or 100 �M significantly decreased the H2O2 content of Day 2 embryos as compared with control embryos (n = 48-53 per group, 7 replicates). These results suggest that the addition of either DPI or DHEA to the medium during the first 2 days of culture did not impair the development of the embryos to the blastocyst stage. Decrease of cellular ROS production in Day 2 embryos in this study is interpreted as a result of inhibition of the NADPH oxidase by DPI or of the G6PDH by DHEA.


2018 ◽  
Vol 30 (1) ◽  
pp. 174
Author(s):  
Y.-J. Niu ◽  
N.-H. Kim ◽  
X.-S. Cui

C-Phycocyanin (CP) is a biliprotein enriched in blue-green algae that is known to possess antioxidant, anti-apoptosis, anti-inflammatory, and radical-scavenging properties in somatic cells. However, the protective effect of CP on porcine embryo developmental competence in vitro remains unclear. In the present study, we investigated the effect of CP on the development of porcine early embryos as well as its underlying mechanisms exposing them to H2O2 to induce oxidative stress. The levels of reactive oxygen species, mitochondrial membrane potential, apoptosis, DNA damage, and autophagy in the blastocysts were observed by staining with 2′,7′-dichlorodihydrofluorescein diacetate (H2DCF-DA), 5,5′,6,6’-tetrachloro-1,1′,3,3′-tetraethyl-imidacarbocyanine iodide (JC-1), terminal deoxynucleotidyl transferase-mediated 2′-deoxyuridine 5′-triphosphate (dUTP) nick-end labelling (TUNEL), anti-cytochrome c, and anti-γH2A.X (Ser139), respectively. Colocalization assay of mitochondria and cytochrome c of blastocysts were staining with MitoTracker Red CMXRos and anti-cytochrome c. All data were subjected to one-way ANOVA. Different concentrations of CP (1, 2, 5, 8, 10 µg mL−1) were added to porcine zygote medium 5 (PZM-5, l-glutamine concentration of PZM-3 was modified from 1 to 2 mM) during in vitro culture. The results showed that 5 µg mL−1 CP significantly increased blastocyst formation (62.5 ± 2.1 v. 52.7 ± 2.4; P < 0.05) and hatching rate (10.9 ± 1.9 v. 36.6 ± 5.2; P < 0.05) compared with controls. Blastocyst formation (53.1 ± 2.3 v. 40.1 ± 2.3; P < 0.05) and quality were significantly increased in the 50 µM H2O2 treatment group following 5 µg mL−1 CP addition. C-Phycocyanin prevented the H2O2-induced compromise of mitochondrial membrane potential, release of cytochrome c from the mitochondria, and generation of reactive oxygen species. Furthermore, apoptosis, DNA damage level, and autophagy in the blastocysts were attenuated by supplementation of CP in the H2O2-induced oxidative injury group compared with that in controls. These results suggest that CP has beneficial effects on the development of porcine parthenotes by attenuating mitochondrial dysfunction and oxidative stress.


Zygote ◽  
2019 ◽  
Vol 28 (1) ◽  
pp. 59-64
Author(s):  
Yuhan Zhao ◽  
Yongnan Xu ◽  
Yinghua Li ◽  
Qingguo Jin ◽  
Jingyu Sun ◽  
...  

SummaryKaempferol (KAE) is one of the most common dietary flavonols possessing biological activities such as anticancer, anti-inflammatory and antioxidant effects. Although previous studies have reported the biological activity of KAE on a variety of cells, it is not clear whether KAE plays a similar role in oocyte and embryo in vitro culture systems. This study investigated the effect of KAE addition to in vitro maturation on the antioxidant capacity of embryos in porcine oocytes after parthenogenetic activation. The effects of kaempferol on oocyte quality in porcine oocytes were studied based on the expression of related genes, reactive oxygen species, glutathione and mitochondrial membrane potential as criteria. The rate of blastocyst formation was significantly higher in oocytes treated with 0.1 µm KAE than in control oocytes. The mRNA level of the apoptosis-related gene Caspase-3 was significantly lower in the blastocysts derived from KAE-treated oocytes than in the control group and the mRNA expression of the embryo development-related genes COX2 and SOX2 was significantly increased in the KAE-treated group compared with that in the control group. Furthermore, the level of intracellular reactive oxygen species was significantly decreased and that of glutathione was significantly increased after KAE treatment. Mitochondrial membrane potential (ΔΨm) was increased and the activity of Caspase-3 was significantly decreased in the KAE-treated group compared with that in the control group. Taken together, these results suggested that KAE is beneficial for the improvement of embryo development by inhibiting oxidative stress in porcine oocytes.


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