Mitigation of Glucolipotoxicity-Induced Apoptosis, Mitochondrial Dysfunction, and Metabolic Stress by N-Acetyl Cysteine in Pancreatic β-Cells

Glucolipotoxicity caused by hyperglycemia and hyperlipidemia are the common features of diabetes-induced complications. Metabolic adaptation, particularly in energy metabolism; mitochondrial dysfunction; and increased inflammatory and oxidative stress responses are considered to be the main characteristics of diabetes and metabolic syndrome. However, due to various fluctuating endogenous and exogenous stimuli, the precise role of these factors under in vivo conditions is not clearly understood. In the present study, we used pancreatic β-cells, Rin-5F, to elucidate the molecular and metabolic changes in glucolipotoxicity. Cells treated with high glucose (25 mM) and high palmitic acid (up to 0.3 mM) for 24 h exhibited increased caspase/poly-ADP ribose polymerase (PARP)-dependent apoptosis followed by DNA fragmentation, alterations in mitochondrial membrane permeability, and bioenergetics, accompanied by alterations in glycolytic and mitochondrial energy metabolism. Our results also demonstrated alterations in the expression of mammalian target of rapamycin (mTOR)/5′ adenosine monophosphate-activated protein kinase (AMPK)-dependent apoptotic and autophagy markers. Furthermore, pre-treatment of cells with 10 mM N-acetyl cysteine attenuated the deleterious effects of high glucose and high palmitic acid with improved cellular functions and survival. These results suggest that the presence of high energy metabolites enhance mitochondrial dysfunction and apoptosis by suppressing autophagy and adapting energy metabolism, mediated, at least in part, via enhanced oxidative DNA damage and mTOR/AMPK-dependent cell signaling.

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Augmentation of Glucotoxicity, Oxidative Stress, Apoptosis and Mitochondrial Dysfunction in HepG2 Cells by Palmitic Acid

Nutrients ◽

10.3390/nu11091979 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1979 ◽

Cited By ~ 6

Author(s):

Arwa Alnahdi ◽

Annie John ◽

Haider Raza

Keyword(s):

Oxidative Stress ◽

Cell Signaling ◽

Palmitic Acid ◽

Mitochondrial Dysfunction ◽

Stress Responses ◽

High Glucose ◽

Hepg2 Cells ◽

High Energy ◽

Redox Stress ◽

Energy Metabolites

Hyperglycemia and hyperlipidemia are the hallmarks of diabetes and obesity. Experimental and epidemiological studies have suggested that dietary management and caloric restriction are beneficial in reducing the complications of diabesity. Studies have suggested that increased availability of energy metabolites like glucose and saturated fatty acids induces metabolic, oxidative, and mitochondrial stress, accompanied by inflammation that may lead to chronic complications in diabetes. In the present study, we used human hepatoma HepG2 cells to investigate the effects of high glucose (25 mM) and high palmitic acid (up to 0.3 mM) on metabolic-, inflammatory-, and redox-stress-associated alterations in these cells. Our results showed increased lipid, protein, and DNA damage, leading to caspase-dependent apoptosis and mitochondrial dysfunction. Glucolipotoxicity increased ROS production and redox stress appeared to alter mitochondrial membrane potential and bioenergetics. Our results also demonstrate the enhanced ability of cytochrome P450s-dependent drug metabolism and antioxidant adaptation in HepG2 cells treated with palmitic acid, which was further augmented with high glucose. Altered NF-kB/AMPK/mTOR-dependent cell signaling and inflammatory (IL6/TNF-α) responses were also observed. Our results suggest that the presence of high-energy metabolites enhances apoptosis while suppressing autophagy by inducing inflammatory and oxidative stress responses that may be responsible for alterations in cell signaling and metabolism.

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Attenuating effect of silibinin on palmitic acid-induced apoptosis and mitochondrial dysfunction in pancreatic β-cells is mediated by estrogen receptor alpha

Molecular and Cellular Biochemistry ◽

10.1007/s11010-019-03572-1 ◽

2019 ◽

Vol 460 (1-2) ◽

pp. 81-92 ◽

Cited By ~ 9

Author(s):

Yue Sun ◽

Jing Yang ◽

Weiwei Liu ◽

Guodong Yao ◽

Fanxing Xu ◽

...

Keyword(s):

Estrogen Receptor ◽

Palmitic Acid ◽

Mitochondrial Dysfunction ◽

Estrogen Receptor Alpha ◽

Β Cells ◽

Pancreatic Β Cells ◽

Receptor Alpha ◽

Induced Apoptosis

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Astragalus polysaccharide improve the proliferation and insulin secretion of mouse pancreatic β cells induced by high glucose and palmitic acid partially through promoting miR-136-5p and miR-149-5p expression

Bioengineered ◽

10.1080/21655979.2021.1996314 ◽

2021 ◽

Author(s):

Shifang Deng ◽

Lei Yang ◽

Ke Ma ◽

Wei Bian

Keyword(s):

Insulin Secretion ◽

Palmitic Acid ◽

High Glucose ◽

Β Cells ◽

Pancreatic Β Cells ◽

Astragalus Polysaccharide

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Cytoprotective Effects of N-Acetylcysteine on Streptozotocin- Induced Oxidative Stress and Apoptosis in RIN-5F Pancreatic β-Cells

Cellular Physiology and Biochemistry ◽

10.1159/000495200 ◽

2018 ◽

Vol 51 (1) ◽

pp. 201-216 ◽

Cited By ~ 8

Author(s):

Arwa M.T. Al-Nahdi ◽

Annie John ◽

Haider Raza

Keyword(s):

Oxidative Stress ◽

Insulin Secretion ◽

Molecular Mechanisms ◽

Protective Action ◽

Mitochondrial Enzymes ◽

Partial Recovery ◽

Β Cells ◽

Pancreatic Β Cells ◽

Mitochondrial Energy Metabolism ◽

Mitochondrial Functions

Background/Aims: Numerous studies have reported overproduction of reactive oxygen species (ROS) and alterations in mitochondrial energy metabolism in the development of diabetes and its complications. The potential protective effects of N-acetylcysteine (NAC) in diabetes have been reported in many therapeutic studies. NAC has been shown to reduce oxidative stress and enhance redox potential in tissues protecting them against oxidative stress associated complications in diabetes. In the current study, we aimed to investigate the molecular mechanisms of the protective action of NAC on STZ-induced toxicity in insulin secreting Rin-5F pancreatic β-cells. Methods: Rin-5F cells were grown to 80% confluence and then treated with 10mM STZ for 24h in the presence or absence of 10mM NAC. After sub-cellular fractionation, oxidative stress, GSH-dependent metabolism and mitochondrial respiratory functions were studied using spectrophotometric, flow cytometric and Western blotting techniques. Results: Our results showed that STZ-induced oxidative stress and apoptosis caused inhibition in insulin secretion while NAC treatment restored the redox homeostasis, enhanced insulin secretion in control cells and prevented apoptosis in STZ-treated cells. Moreover, NAC attenuated the inhibition of mitochondrial functions induced by STZ through partial recovery of the mitochondrial enzymes and restoration of membrane potential. STZ-induced DNA damage and expression of apoptotic proteins were significantly inhibited in NAC-treated cells. Conclusion: Our results suggest that the cytoprotective action of NAC is mediated via suppression of oxidative stress and apoptosis and restoration of GSH homeostasis and mitochondrial bioenergetics. This study may, thus, help in better understanding the cellular defense mechanisms of pancreatic β-cells against STZ-induced cytotoxicity.

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Xiaokeping-induced autophagy protects pancreatic β-cells against apoptosis under high glucose stress

Biomedicine & Pharmacotherapy ◽

10.1016/j.biopha.2018.05.147 ◽

2018 ◽

Vol 105 ◽

pp. 407-412 ◽

Cited By ~ 3

Author(s):

Yanyang Wu ◽

Yongquan Hu ◽

Zhou Haiyan ◽

Wei YunLin ◽

Kang Xincong ◽

...

Keyword(s):

High Glucose ◽

Β Cells ◽

Pancreatic Β Cells

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Chebulic Acid Prevents Methylglyoxal-Induced Mitochondrial Dysfunction in INS-1 Pancreatic β-Cells

Antioxidants ◽

10.3390/antiox9090771 ◽

2020 ◽

Vol 9 (9) ◽

pp. 771

Author(s):

Hyun-jung Yoo ◽

Chung-Oui Hong ◽

Sang Keun Ha ◽

Kwang-Won Lee

Keyword(s):

Enzyme Activity ◽

Protein Expression ◽

Western Blot ◽

Mitochondrial Dysfunction ◽

Atp Synthesis ◽

Ros Production ◽

Β Cells ◽

Pancreatic Β Cells ◽

Chebulic Acid ◽

Cyt C

To investigate the anti-diabetic properties of chebulic acid (CA) associated with the prevention of methyl glyoxal (MG)-induced mitochondrial dysfunction in INS-1 pancreatic β-cells, INS-1 cells were pre-treated with CA (0.5, 1.0, and 2.0 μM) for 48 h and then treated with 2 mM MG for 8 h. The effects of CA and MG on INS-1 cells were evaluated using the following: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; glyoxalase 1 (Glo-1) expression via Western blot and enzyme activity assays; Nrf-2, nuclear factor erythroid 2-related factor 2 protein expression via Western blot assay; reactive oxygen species (ROS) production assay; mRNA expression of mitochondrial dysfunction related components (UCP2, uncoupling protein 2; VDAC1, voltage-dependent anion-selective channel-1; cyt c, cytochrome c via quantitative reverse transcriptase-PCR; mitochondrial membrane potential (MMP); adenosine triphosphate (ATP) synthesis; glucose-stimulated insulin secretion (GSIS) assay. The viability of INS-1 cells was maintained upon pre-treating with CA before exposure to MG. CA upregulated Glo-1 protein expression and enzyme activity in INS-1 cells and prevented MG-induced ROS production. Mitochondrial dysfunction was alleviated by CA pretreatment; this occurred via the downregulation of UCP2, VDAC1, and cyt c mRNA expression and the increase of MMP and ATP synthesis. Further, CA pre-treatment promoted the recovery from MG-induced decrease in GSIS. These results indicated that CA could be employed as a therapeutic agent in diabetes due to its ability to prevent MG-induced development of insulin sensitivity and oxidative stress-induced dysfunction of β-cells.

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Delphinidin-induced autophagy protects pancreatic β cells against apoptosis resulting from high-glucose stress via AMPK signaling pathway

Acta Biochimica et Biophysica Sinica ◽

10.1093/abbs/gmz126 ◽

2019 ◽

Vol 51 (12) ◽

pp. 1242-1249 ◽

Cited By ~ 5

Author(s):

Dengni Lai ◽

Mingyong Huang ◽

Lingyan Zhao ◽

Yan Tian ◽

Yong Li ◽

...

Keyword(s):

Signaling Pathway ◽

High Glucose ◽

Cell Mass ◽

Protective Role ◽

Common Disease ◽

Β Cells ◽

Pancreatic Β Cells ◽

Ampk Signaling ◽

Compound C ◽

Induced Apoptosis

Abstract Hyperglycemia, a diagnostic characteristic of diabetes mellitus, is detrimental to pancreatic β cells. Delphinidin, a member of the anthocyanin family, inhibits glucose absorption, increases glucagon-like peptide-1 (GLP-1) secretion, and improves insulin secretion in diabetes. However, whether delphinidin plays a protective role in pancreatic β-cell mass and function is not clear. In this study, delphinidin was found to decrease the high-glucose-induced apoptosis of RIN-m5F pancreatic β cells. In addition, delphinidin induced autophagy in RIN-m5F cells under the normal and high-glucose conditions, while 3-methyladenine (3-MA) inhibition of autophagy significantly diminished the protective role of delphinidin against high-glucose-induced apoptosis of pancreatic β cells. Delphinidin also decreased the level of cleaved caspase 3 and increased the phosphorylation level of AMP-activated protein kinase α (AMPKα) Thr172. Compound C, an AMPK inhibitor, was found to decrease the ratio of LC3-II/LC3-I, and the apoptotic rate of high-glucose-injured cells was increased after treatment with delphinidin, indicating that delphinidin attenuated the negative effects of high-glucose stress to cells. In conclusion, our data demonstrate that delphinidin protects pancreatic β cells against high-glucose-induced injury by autophagy regulation via the AMPK signaling pathway. These findings might shed light on the underlying mechanisms of diabetes and help improve the prevention and therapy of this common disease.

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Comparison of the Effects of Cyclosporin a on the Metabolism of Perfused Rat Brain Slices during Normoxia and Hypoxia

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-200203000-00012 ◽

2002 ◽

Vol 22 (3) ◽

pp. 342-352 ◽

Cited By ~ 15

Author(s):

Natalie Serkova ◽

Paul Donohoe ◽

Sven Gottschalk ◽

Carsten Hainz ◽

Claus U. Niemann ◽

...

Keyword(s):

Energy Metabolism ◽

Cyclosporin A ◽

Rat Brain ◽

Ex Vivo ◽

Brain Slices ◽

High Energy ◽

Metabolic Effects ◽

Resonance Spectroscopy ◽

Buffer Solution ◽

Mitochondrial Energy Metabolism

The authors evaluated and compared the metabolic effects of cyclosporin A in the rat brain during normoxia and hypoxia/reperfusion. Ex vivo31P magnetic resonance spectroscopy experiments based on perfused rat brain slices showed that under normoxic conditions, 500 μg/L cyclosporin A significantly reduced mitochondrial energy metabolism (nucleotide triphosphate, 83 ± 9% of controls; phosphocreatine, 69 ± 9%) by inhibition of the Krebs cycle (glutamate, 77 ± 5%) and oxidative phosphorylation (NAD+, 65 ± 14%) associated with an increased generation of reactive oxygen species (285 ± 78% of control). However, the same cyclosporin A concentration (500 μg/L) was found to be the most efficient concentration to inhibit the hypoxia-induced mitochondrial release of Ca2+ in primary rat hippocampal cells with cytosolic Ca2+ concentrations not significantly different from normoxic controls. Addition of 500 μg/L cyclosporin A to the perfusion medium protected high-energy phosphate metabolism (nucleotide triphosphate, 11 ± 15% of control vs. 35 ± 9% with 500 μg/L cyclosporin A) and the intracellular pH (6.2 ± 0.1 control vs. 6.6 ± 0.1 with cyclosporin A) in rat brain slices during 30 minutes of hypoxia. Results indicate that cyclosporin A simultaneously decreases and protects cell glucose and energy metabolism. Whether the overall effect was a reduction or protection of cell energy metabolism depended on the concentrations of both oxygen and cyclosporin A in the buffer solution.

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