Nifedipine prevents etoposide-induced caspase-3 activation, prenyl transferase degradation and loss in cell viability in pancreatic β-cells

Background: Cucurbita Argyrosperma seeds have acquired a reputation as an herbal remedy to treat various diseases because this plant is a predominant source of natural compounds with potent anti-inflammatory, antioxidant properties, and seed supplementation improves oxidative stress. Previous studies indicated that an imbalance between H2O2 production and elimination capacity is responsible for β-cell vulnerability, making β-cell a target susceptible to pathological disasters.This investigation aimed to evaluate the protective effects of one new multiflorane-type triterpene 3β-trans-caffeoyloxymultiflor-8-ene- 7α,12β, 18 β-triol (1) from MeOH extract from C. Argyrosperma, on rat pancreatic β cells (INS-1 cells) exposed to hydrogen peroxide (H2O2) induced oxidative stress conditions.Methods: The chemical structure of the novel triterpene, which was identified as 3β-trans-caffeoyloxymultiflor-8-ene- 7α,12β, 18 β-triol (1), was established based on the interpretation of spectroscopic analyses. The antioxidant activities of 1 were leaded by detect radical scavenging potential of 2,2-dyphenyl-1-picrylhydrazyl (DPPH) and 3.1 2,2′-Azino-bis(3-Ethylbenzothiazoline-6-Sulfonic Acid) ABTS. The assays were conducted on INS-1 cells line exposed to increasing concentrations of 1 at 5,10 and 20 µg/mL and H2O2 at 250 µM. Then, the experiments, cell viability, cell integrity ((LDH; lactate dehydrogenase release), mitochondrial function (ATP analysis), ROS formation, lipid peroxidation (MDA) and caspase-3, 9 activities were measured in the cells. We also determined the effect of 1 on antioxidant enzyme levels and cytotoxicity in pancreatic β cells under oxidant conditions.Results: The results showed that triterpene displayed high free-radical-scavenging activity, which is similar to that of standard antioxidants used. At concentrations of 5, 10, and 20 𝜇g/mL protect INS-1 cells against H2O2 induced cytotoxicity decrease in cell death, with a marked increase in cell viability, sustained cellular functionality (ATP). Antioxidant enzymes such as glutathione peroxidase (GPx), glutathione reduced (GSH), catalase (CAT), superoxide dismutase (SOD), and the non-antioxidant enzyme (GSH) increased in INS-1 cells with 1 pretreatment. MDA in pancreatic cells was ameliorated by 1 pretreatment reducing intracellular reactive oxygen species level. Findings also demonstrated that H2O2-induced apoptosis in INS-1 cells and produced modulation of the caspase-3, 9 expressions in INS-1 cells exposed to 1. Exposure to 1significantly inhibited ROS and apoptosis production, reducing β cell dysfunction under oxidant conditions.Conclusions: Triterpene consequently could be a promising natural antioxidant for use in maintaining the integrity of pancreatic β-cells exposed to oxidative stress conditions being able to participate in the control type 2 diabetes.Keywords: Cucurbita Argyrosperma; antioxidants; multiflorane; free radical scavenging: oxidative stress

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Zurampic Protects Pancreatic β-Cells from High Uric Acid Induced-Damage by Inhibiting URAT1 and Inactivating the ROS/AMPK/ERK Pathways

Cellular Physiology and Biochemistry ◽

10.1159/000490184 ◽

2018 ◽

Vol 47 (3) ◽

pp. 1074-1083 ◽

Cited By ~ 4

Author(s):

Ying Xin ◽

Kun Wang ◽

Zhaotong Jia ◽

Tao Xu ◽

Qiang Xu ◽

...

Keyword(s):

Uric Acid ◽

Cell Viability ◽

Mrna Expression ◽

Caspase 3 ◽

Dependent Manner ◽

Β Cells ◽

Pancreatic Β Cells ◽

Underlying Mechanisms ◽

High Level ◽

High Uric Acid

Background/Aims: Zurampic is a US FDA approved drug for treatment of gout. However, the influence of Zurampic on pancreatic β-cells remains unclear. The study aimed to evaluate the effects of Zurampic on high uric acid-induced damage of pancreatic β-cells and the possible underlying mechanisms. Methods: INS-1 cells and primary rat islets were stimulated with Zurampic and the mRNA expression of urate transporter 1 (URAT1) was assessed by qRT-PCR. Cells were stimulated with uric acid or uric acid plus Zurampic, and cell viability, apoptosis and ROS release were measured by MTT and flow cytometry assays. Western blot analysis was performed to evaluate the expressions of active Caspase-3 and phosphorylation of AMPK and ERK. Finally, cells were stimulated with uric acid or uric acid plus Zurampic at low/high level of glucose (2.8/16.7 mM glucose), and the insulin release was assessed by ELISA. Results: mRNA expression of URAT1 was decreased by Zurampic in a dose-dependent manner. Uric acid decreased cell viability, promoted cell apoptosis and induced ROS release. Uric acid-induced alterations could be reversed by Zurampic. Activation of Caspase-3 and phosphorylation of AMPK and ERK were enhanced by uric acid, and the enhancements were reversed by Zurampic. Decreased phosphorylation of AMPK and ERK, induced by Zurampic, was further reduced by adding inhibitor of AMPK or ERK. Besides, uric acid inhibited high glucose-induced insulin secretion and the inhibition was rescued by Zurampic. Conclusions: Zurampic has a protective effect on pancreatic β-cells against uric acid induced-damage by inhibiting URAT1 and inactivating the ROS/AMPK/ERK pathway.

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Inhibition of Prenylation Promotes Caspase 3 Activation, Lamin B Degradation and Loss in Metabolic Cell Viability in Pancreatic β-Cells

Cellular Physiology and Biochemistry ◽

10.1159/000481702 ◽

2017 ◽

Vol 43 (3) ◽

pp. 1052-1063 ◽

Cited By ~ 2

Author(s):

Khadija G. Syeda ◽

Anjan Kowluru

Keyword(s):

Cell Viability ◽

Caspase 3 ◽

Cell Function ◽

Protein Prenylation ◽

Β Cells ◽

Pancreatic Β Cells ◽

Intermediate Filament Proteins ◽

Lamin B ◽

Metabolic Defects ◽

Cell Proliferation Inhibition

Background/Aims: Lamins are intermediate filament proteins that constitute the main components of the lamina underlying the inner-nuclear membrane and serve to organize chromatin. Lamins (e.g., lamin B) undergo posttranslational modifications (e.g., isoprenylation) at their C-terminal cysteine residues. Such modifications are thought to render optimal association of lamins with the nuclear envelop. Using human islets, rodent islets, and INS-1 832/13 cells, we recently reported significant metabolic defects under glucotoxic and endoplasmic reticulum (ER) stress conditions, including caspase 3 activation and lamin B degradation. The current study is aimed at further understanding the regulatory roles of protein prenylation in the induction of the aforestated metabolic defects. Methods: Subcellular phase partitioning assay was done using Triton X-114. Cell morphology and metabolic cell viability assays were carried out using standard methodologies. Results: We report that exposure of pancreatic β-cells to Simvastatin, an inhibitor of mevalonic acid (MVA) biosynthesis, and its downstream isoprenoid derivatives, or FTI-277, an inhibitor of farnesyltransferase that mediates farnesylation of lamins, leads to activation of caspase 3 and lamin B degradation. Furthermore, Simvastatin-treatment increased activation of p38MAPK (a stress kinase) and inhibited ERK1/2 (regulator of cell proliferation). Inhibition of farnesylation also resulted in the release of degraded lamin B into the cytosolic fraction and promoted loss in metabolic cell viability. Conclusion: Based on these findings we conclude that protein prenylation plays key roles in islet β-cell function. These findings affirm further support to the hypothesis that defects in prenylation pathway induce caspase-3 activation and nuclear lamin degradation in pancreatic β-cells under the duress of metabolic stress (e.g., glucotoxicity).

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Nitric oxide interacts with cholinoceptors to modulate insulin secretion by pancreatic β cells

Pflügers Archiv - European Journal of Physiology ◽

10.1007/s00424-020-02443-9 ◽

2020 ◽

Vol 472 (10) ◽

pp. 1469-1480

Author(s):

Bashair M. Mussa ◽

Ankita Srivastava ◽

Abdul Khader Mohammed ◽

Anthony J. M. Verberne

Keyword(s):

Nitric Oxide ◽

Insulin Secretion ◽

Cell Viability ◽

Combined Treatment ◽

No Production ◽

Β Cells ◽

Β Cell ◽

Pancreatic Β Cells ◽

Tnf Α ◽

Ifn Γ

Abstract Dysfunction of the pancreatic β cells leads to several chronic disorders including diabetes mellitus. Several mediators and mechanisms are known to be involved in the regulation of β cell secretory function. In this study, we propose that cytokine-induced nitric oxide (NO) production interacts with cholinergic mechanisms to modulate insulin secretion from pancreatic β cells. Using a rat insulinoma cell line INS-1, we demonstrated that β cell viability decreases significantly in the presence of SNAP (NO donor) in a concentration- and time-dependent manner. Cell viability was also found to be decreased in the presence of a combined treatment of SNAP with SMN (muscarinic receptor antagonist). We then investigated the impact of these findings on insulin secretion and found a significant reduction in glucose uptake by INS-1 cells in the presence of SNAP and SMN as compared with control. Nitric oxide synthase 3 gene expression was found to be significantly reduced in response to combined treatment with SNAP and SMN suggesting an interaction between the cholinergic and nitrergic systems. The analysis of gene and protein expression further pin-pointed the involvement of M3 muscarinic receptors in the cholinergic pathway. Upon treatment with cytokines, reduced cell viability was observed in the presence of TNF-α and IFN-γ. A significant reduction in insulin secretion was also noted after treatment with TNF-α and IFN-γ and IL1-β. The findings of the present study have shown for the first time that the inhibition of the excitatory effects of cholinergic pathways on glucose-induced insulin secretion may cause β cell injury and dysfunction of insulin secretion in response to cytokine-induced NO production.

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Glycated Albumin Causes Pancreatic β-Cells Dysfunction Through Autophagy Dysfunction

Endocrinology ◽

10.1210/en.2013-1031 ◽

2013 ◽

Vol 154 (8) ◽

pp. 2626-2639 ◽

Cited By ~ 17

Author(s):

Young Mi Song ◽

Sun Ok Song ◽

Young-Hye You ◽

Kun-Ho Yoon ◽

Eun Seok Kang ◽

...

Keyword(s):

Caspase 3 ◽

Glycated Albumin ◽

Nuclear Factor Κb ◽

Nuclear Factor ◽

Bafilomycin A1 ◽

Β Cells ◽

Β Cell ◽

Pancreatic Β Cells ◽

Autophagy Induction ◽

Interfering Rna

Abstract Growing evidence suggests that advanced glycation end-products (AGEs) are cytotoxic to pancreatic β-cells. The aims of this study were to investigate whether glycated albumin (GA), an early precursor of AGEs, would induce dysfunction in pancreatic β-cells and to determine which kinds of cellular mechanisms are activated in GA-induced β-cell apoptosis. Decreased viability and increased apoptosis were induced in INS-1 cells treated with 2.5 mg/mL GA under 16.7mM high-glucose conditions. Insulin content and glucose-stimulated secretion from isolated rat islets were reduced in 2.5 mg/mL GA-treated cells. In response to 2.5 mg/mL GA in INS-1 cells, autophagy induction and flux decreased as assessed by green fluorescent protein–microtubule-associated protein 1 light chain 3 dots, microtubule-associated protein 1 light chain 3-II conversion, and SQSTM1/p62 in the presence and absence of bafilomycin A1. Accumulated SQSTM1/p62 through deficient autophagy activated the nuclear factor-κB (p65)-inducible nitric oxide synthase-caspase-3 cascade, which was restored by treatment with small interfering RNA against p62. Small interfering RNA treatment against autophagy-related protein 5 significantly inhibited the autophagy machinery resulting in a significant increase in iNOS-cleaved caspase-3 expression. Treatment with 500μM 4-phenyl butyric acid significantly alleviated the expression of endoplasmic reticulum stress markers and iNOS in parallel with upregulated autophagy induction. However, in the presence of bafilomycin A1, the decreased viability of INS-1 cells was not recovered. Glycated albumin, an early precursor of AGE, caused pancreatic β-cell death by inhibiting autophagy induction and flux, resulting in nuclear factor-κB (p65)-iNOS-caspase-3 cascade activation as well as by increasing susceptibility to endoplasmic reticulum stress and oxidative stress.

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Uptake of nicotinamide by rat pancreatic β cells with regard to streptozotocin action

Journal of Endocrinology ◽

10.1677/joe.0.1310135 ◽

1991 ◽

Vol 131 (1) ◽

pp. 135-138 ◽

Cited By ~ 5

Author(s):

M. Sofue ◽

Y. Yoshimura ◽

M. Nishida ◽

J. Kawada

Keyword(s):

Cell Viability ◽

Succinic Dehydrogenase ◽

Facilitated Diffusion ◽

Dependent Manner ◽

Β Cells ◽

Pancreatic Β Cells ◽

Intracellular Atp ◽

Atp Concentration ◽

Dose Dependent Decrease ◽

Dose Dependent

ABSTRACT Exposure of rat pancreatic β cells in monolayer culture to 2 mmol streptozotocin (STZ)/1 for 1 h followed by thorough washing inhibited their uptake of [14C]nicotinamide and [3H]2-deoxyglucose ([2H]2-DG) to about 50% and also reduced the intracellular ATP concentration to 50% of that in control cells. These changes were not due to a lethal cytotoxic effect of STZ, because cell viability, as estimated by succinic dehydrogenase activity, was 90% of that of control cells. Oligomycin and carbonylcyanide-m-chlorophenylhydrazone (CCCP), an uncoupler of oxidative phosphorylation, caused a dose-dependent decrease in intracellular ATP concentration while maintaining high cell viability. These ATP-depleted cells showed a decrease in insulin release and an inhibition of the uptake of [14C]nicotinamide and [3H]2-DG in a dose-dependent manner. Therefore oligomycin and CCCP reproduced the same effects as those found in β cells treated with STZ. These results suggest that the uptake of nicotinamide and 2-DG by β cells might be regulated by their intracellular ATP concentration. The decreased uptake of nicotinamide in ATP-depleted β cells caused by STZ might explain the lack of protective effect of nicotinamide against STZ cytotoxicity when administered after the latter. Furthermore, the radiotracer experiments demonstrated that the transport of nicotinamide by intact β cells was inhibited in a dose-dependent manner by 2-DG and vice versa, i.e. the transport of 2-DG was inhibited by nicotinamide. These findings suggest the existence of a common transport mechanism in β cells responsible for the uptake of nicotinamide and 2-DG, the transport of which is known to occur by facilitated diffusion. Journal of Endocrinology (1991) 131, 135–138

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Differential responses of pancreatic β-cells to ROS and RNS

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00424.2012 ◽

2013 ◽

Vol 304 (6) ◽

pp. E614-E622 ◽

Cited By ~ 22

Author(s):

Gordon P. Meares ◽

Dominique Fontanilla ◽

Katarzyna A. Broniowska ◽

Teresa Andreone ◽

Jack R. Lancaster ◽

...

Keyword(s):

Nitric Oxide ◽

Dna Damage ◽

Cell Death ◽

Cell Viability ◽

Cell Fate ◽

Β Cells ◽

Pancreatic Β Cells ◽

Unfolded Protein ◽

Heat Shock Responses ◽

Reduce Cell Viability

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) direct the activation of distinct signaling pathways that determine cell fate. In this study, the pathways activated and the mechanisms by which ROS and RNS control the viability of pancreatic β-cells were examined. Although both nitric oxide and hydrogen peroxide (H2O2) induce DNA damage, reduce cell viability, and activate AMPK, the mechanisms of AMPK activation and cell death induction differ between each reactive species. Nitric oxide activates the unfolded protein and heat shock responses and MAPK kinase signaling, whereas H2O2 stimulates p53 stabilization and poly(ADP-ribose) polymerase (PARP) activation but fails to induce the unfolded protein or heat shock responses or MAPK activation. The control of cell fate decisions is selective for the form of stress. H2O2-mediated reduction in β-cell viability is controlled by PARP, whereas cell death in response to nitric oxide is PARP independent but associated with the nuclear localization of GAPDH. These findings show that both ROS and RNS activate AMPK, induce DNA damage, and reduce cell viability; however, the pathways controlling the responses of β-cells are selective for the type of reactive species.

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Phagocyte-like NADPH oxidase promotes cytokine-induced mitochondrial dysfunction in pancreatic β-cells: evidence for regulation by Rac1

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00421.2010 ◽

2011 ◽

Vol 300 (1) ◽

pp. R12-R20 ◽

Cited By ~ 35

Author(s):

Wasanthi Subasinghe ◽

Ismail Syed ◽

Anjaneyulu Kowluru

Keyword(s):

Nadph Oxidase ◽

Mitochondrial Dysfunction ◽

Caspase 3 ◽

Primary Source ◽

Significant Loss ◽

Ros Generation ◽

Β Cells ◽

Pancreatic Β Cells ◽

Subunit Expression ◽

Cellular Signal

Reactive oxygen species (ROS) are important mediators of cellular signal transduction cascades such as proliferation, migration, and apoptosis. Chronic exposure of isolated β-cells to proinflammatory cytokines elevates intracellular oxidative stress leading to the demise of pancreatic β-cells culminating in the onset of diabetes. Although the mitochondrial electron transport chain is felt to be the primary source of ROS, several lines of recent evidence suggest that phagocyte-like NADPH oxidase plays a central role in cytokine-mediated ROS generation and apoptosis of β-cells. However, the precise mechanisms underlying the regulation of NADPH oxidase remain unknown. To address this, insulin-secreting INS 832/13 cells were treated with cytomix (IL-1β, IFN-γ, and TNF-α; 10 ng/ml each) for different time intervals (0–24 h). A significant, time-dependent increase in NADPH oxidase activation/intracellular ROS production, p47phox subunit, but not p67phox subunit, expression of the phagocyte-like NADPH oxidase were demonstrable under these conditions. Furthermore, siRNA-p47phox transfection or exposure of INS 832/13 cells to apocynin, a selective inhibitor of NADPH oxidase, markedly attenuated cytomix-induced ROS generation in these cells. Cytomix-mediated mitochondrial dysfunction in INS 832/13 cells was evident by a significant loss of mitochondrial membrane potential (MMP) and upregulated caspase 3 activity. Cytomix treatment also caused a transient (within 15 min) activation of Rac1, a component of the NADPH oxidase holoenzyme. Furthermore, GGTI-2147 and NSC23766, known Rac1 inhibitors, not only attenuated the cytomix-induced Rac1 activation but also significantly prevented loss of MMP (NSC23766 > GGTI-2147). However, NSC23766 had no effect on cytomix-induced NO generation or caspase 3 activation, suggesting additional regulatory mechanisms might underlie these signaling steps. Together, these findings suggested that Rac1-mediated regulation of phagocyte-like NADPH oxidase contributes to cytokine-mediated mitochondrial dysfunction in the β-cell.

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The Coffee Diterpene, Kahweol, Ameliorates Pancreatic β-Cell Function in Streptozotocin (STZ)-Treated Rat INS-1 Cells through NF-kB and p-AKT/Bcl-2 Pathways

Molecules ◽

10.3390/molecules26175167 ◽

2021 ◽

Vol 26 (17) ◽

pp. 5167

Author(s):

Waseem El-Huneidi ◽

Shabana Anjum ◽

Khuloud Bajbouj ◽

Eman Abu-Gharbieh ◽

Jalal Taneera

Keyword(s):

Insulin Secretion ◽

Cell Viability ◽

Glucose Uptake ◽

B Cell Lymphoma ◽

Heme Oxygenase 1 ◽

Ros Production ◽

Β Cells ◽

Pancreatic Β Cells ◽

Antioxidant Proteins ◽

The Impact

Kahweol is a diterpene molecule found in coffee that exhibits a wide range of biological activity, including anti-inflammatory and anticancer properties. However, the impact of kahweol on pancreatic β-cells is not known. Herein, by using clonal rat INS-1 (832/13) cells, we performed several functional experiments including; cell viability, apoptosis analysis, insulin secretion and glucose uptake measurements, reactive oxygen species (ROS) production, as well as western blotting analysis to investigate the potential role of kahweol pre-treatment on damage induced by streptozotocin (STZ) treatment. INS-1 cells pre-incubated with different concentrations of kahweol (2.5 and 5 µM) for 24 h, then exposed to STZ (3 mmol/L) for 3 h reversed the STZ-induced effect on cell viability, apoptosis, insulin content, and secretion in addition to glucose uptake and ROS production. Furthermore, Western blot analysis showed that kahweol downregulated STZ-induced nuclear factor kappa B (NF-κB), and the antioxidant proteins, Heme Oxygenase-1 (HMOX-1), and Inhibitor of DNA binding and cell differentiation (Id) proteins (ID1, ID3) while upregulated protein expression of insulin (INS), p-AKT and B-cell lymphoma 2 (BCL-2). In conclusion, our study suggested that kahweol has anti-diabetic properties on pancreatic β-cells by suppressing STZ induced apoptosis, increasing insulin secretion and glucose uptake. Targeting NF-κB, p-AKT, and BCL-2 in addition to antioxidant proteins ID1, ID3, and HMOX-1 are possible implicated mechanisms.

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