Inorganic nitrite alters mitochondrial dynamics without overt changes in cell death and mitochondrial respiration in cardiomyoblasts under hyperglycemia. (February 2021)

• Record Type: Journal Article
• Authors: Anand, C.R.; Bhavya, Bharathan; Jayakumar, K.; Harikrishnan, V.S.; Gopala, Srinivas
• Is Part Of: Toxicology in vitro. Volume 70(2021)
• Publication Date: 2021-02
• Subjects: Nitrite -- Hyperglycemia -- Mitochondria -- Rat cardiac myoblasts -- Dynamin related protein1; ADP adenosine diphosphate -- AMP adenosine monophosphate -- ANOVA analysis of variance -- ATP adenosine triphosphate -- BCA bicinchoninic acid -- cDNA complementary deoxyribonucleic acid -- Ct cycle threshold -- DMEM Dulbecco's modified eagle medium -- DMSO dimethyl sulfoxide -- ETS electron transport system -- FACS fluorescence-activated cell sorting -- FCCP carbonyl cyanide-4-(trifluoromethoxy) phenyl hydrazone -- FBS fetal bovine serum -- HBSS Hanks balanced saline (salt) solution -- H2DCF-DA 2, 7-dichloro dihydro fluorescein diacetate -- HG High Glucose -- HGN High Glucose with Nitrite -- HRP horseradish peroxidase -- JC-1 5, 5′, 6, 6′- tetrachloro-1, 1′, 3, 3′- tetraethyl- benzimidazol carbocyanine iodide -- mRNA messenger ribonucleic acid -- MTT 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) tetrazolium -- NAD(P)H nicotinamide adenine dinucleotide (phosphate) reduced -- NG Normal Glucose -- NGN Normal Glucose with Nitrite -- NOX nitrogen oxides -- PBS phosphate buffered saline -- PVDF polyvinylidene difluoride -- qPCR quantitative polymerase chain reaction -- RIPA radioimmuno precipitation assay -- siRNA small interfering ribonucleic acid; Toxicity testing -- In vitro -- Periodicals; Toxicology -- Periodicals; 615.9
• DOI: 10.1016/j.tiv.2020.105048
• Languages: English
• ISSNs: 0887-2333

Abstract

Abstract: Inorganic nitrate or nitrite supplementation has been reported to demonstrate positive outcomes in rodent models of obesity and diabetes as well as in type 2 diabetic humans and even included in clinical trials pertaining to cardiovascular diseases in the recent decade. However, there are contrasting data regarding the useful and toxic effects of the anions. The primary scope of this study was to analyze the beneficial/detrimental alterations in redox status, mitochondrial dynamics and function, and cellular fitness in cardiomyoblasts inflicted by nitrite under hyperglycemic conditions compared with normoglycemia. Nitrite supplementation in H9c2 myoblasts under high glucose diminishes the Bcl-xL expression and mitochondrial ROS levels without significant initiation of cell death or decline in total ROS levels. Concomitantly, there are tendencies towards lowering of mitochondrial membrane potential, but without noteworthy changes in mitochondrial biogenesis and respiration. The study also revealed that under high glucose stress, nitrite may alter mitochondrial dynamics by Drp1 activation possibly via Akt1-Pim1 axis. Moreover, the study revealed differential effects of Drp1 silencing and/or nitrite under the above glycemic conditions. Overall, the study warrants more research regarding the effects of nitrite therapy in cardiac cells exposed to hyperglycemia. Highlights: Nitrite does not reverse the high glucose-induced changes in H9c2 apoptosis. Membrane potential and superoxide production in mitochondria tend to reduce. Nitrite under high glucose reduces the inhibitory phosphorylation on Drp1. The activity of pro-survival kinases Akt1 and Pim1 concomitantly decline. Inorganic nitrite has no protective effect on cardiomyoblasts under high glucose.