Browsing by Author "Mantha, A.K"

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    Anti-cancer drug doxorubicin induced cardiotoxicity: Understanding the mechanisms involved in ros generation resulting in mitochondrial dysfunction
    (Rasayan Journal of Chemistry, c/o Dr. Pratima Sharma, 2020) Upadhayay, S; Sharma, N; Mantha, A.K; Dhiman, M.
    Doxorubicin (DOX), despite being an effective anti-cancer drug has offsite targets that affect the vital organs such as heart, brain and kidney. DOX-induced cardiotoxicity is reported as a multi-factorial process that interferes with mitochondrial bioenergetics. These responses increase the threshold of oxidant-mediated injury and redox-mediated apoptosis in the cardiomyocytes. Oxidative stress particularly mitochondrial dysfunction in cardiomyocytes associated with cardiovascular diseases. In the present study we examined the effect of DOX on H9c2 cardiomyocyte where cells were treated with 5 μM DOX. To rule out the source of reactive oxygen species (ROS) during DOX-induced toxicity, the DOX-treated cardiomyocytes were incubated with 100 ?M diphenyleneiodonium (DPI), 50 μM salicyl hydroxamic acid (SHX), 20 μM Carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP), which are specific inhibitors of NADPH oxidase (NOX), Myeloperoxidase (MPO), and mitochondrial oxidative phosphorylation respectively and 10 μM N-acetyl cysteine (NAC, free radical scavenger) was also used to perceive the role of ROS. H2O2 (100 ?M) treated H9c2 cardiomyocytes were used as positive controls. The cell viability, reactive oxygen species (ROS) level and oxidative stress were determined using MTT assay, NBT assay/Flow-cytometry and Western blotting based assays. The effect of DOX on mitochondria was evaluated using Amplex Red assay; fluorescent probes such as MitoSOX and MitoTracker were used to examine the DOX-induced ROS production from the mitochondrial matrix. The mitochondrial membrane potential was evaluated using JC-1 dye. Western blotting was performed for cytochrome c release and apoptosis was examined with Annexin V-FITC assay. DOX was found to reduce cell viability, increase ROS level followed by enhanced oxidative stress in the form of protein carbonyls. DOX also showed a reduction in the mitochondrial membrane potential and allowed the release of cytochrome c which further leads to apoptosis and cell death. Further to rule out the pathway/mechanism(s) of DOX-mediated cardiac pathologies, the treatment with inhibitors of the classical ROS sources such as NADPH oxidase, Myeloperoxidase, mitochondria and general ROS scavenger (NAC) suggested that ROS via NOX and MPO during DOX-induced toxicity plays a crucial role in cardiomyocytes. The mitochondrial integrity was conserved when the cells were treated with NOX and MPO inhibitors, the cytochrome C release and apoptosis reduced in presence of these inhibitors. Taken together, these results demonstrate that DOX leads to ROS production and oxidative stress in cardiomyocytes which ultimately affects the mitochondrial integrity and functions, most importantly the ROS released via NOX and MPO is critical during DOX-induced cardiotoxicity. - RAS?YAN. All rights reserved.
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    Glycyrrhiza glabra (Licorice) root extract attenuates doxorubicin-induced cardiotoxicity via alleviating oxidative stress and stabilising the cardiac health in H9c2 cardiomyocytes
    (Elsevier, 2020) Upadhyay, S; Mantha, A.K; Dhiman, Monisha
    Ethnopharmacological relevance: Doxorubicin (DOX) is an effective anti-neoplastic drug, however; it has downside effects on cardiac health and other vital organs. The herbal remedies used in day to day life may have a beneficial effect without disturbing the health of the vital organs. Glycyrrhiza glabra L. is a ligneous perennial shrub belonging to Leguminosae/Fabaceae/Papilionaceae family growing in Mediterranean region and Asia and widespread in Turkey, Italy, Spain, Russia, Syria, Iran, China, India and Israel. Commonly known as mulaithi in north India, G. glabra has glycyrrhizin, glycyrrhetic acid, isoliquiritin, isoflavones, etc., which have been reported for several pharmacological activities such as anti-demulcent, anti-ulcer, anti-cancer, anti-inflammatory and anti-diabetic. Aim of the study: The objective of the present study is to investigate the interaction between the molecular factors like PPAR-?/? and SIRT-1 during cardiac failure arbitrated by DOX under in vitro conditions and role of Glycyrrhiza glabra (Gg) root extract in alleviating these affects. Materials and methods: In the present study, we have examined the DOX induced responses in H9c2 cardiomyocytes and investigated the role of phytochemical Glycyrrhiza glabra in modulating these affects. MTT assay was done to evaluate the cell viability, Reactive Oxygen Species (ROS)/Reactive Nitrogen Species (RNS) levels, mitochondrial ROS, mitochondrial membrane potential was estimated using fluorescent probes. The oxidative stress in terms of protein carbonylation, lipid peroxidation and DNA damage was detected via spectrophotometric methods and immune-fluorescence imaging. The cardiac markers and interaction between SIRT-1 and PPAR-?/? was measured using Real-Time PCR, Western blotting and Co-immunoprecipitation based studies. Results: The Glycyrrhiza glabra (Gg) extracts maintained the membrane integrity and improved the lipid homeostasis and stabilized cytoskeletal element actin. Gg phytoextracts attenuated aggravated ROS level, repaired the antioxidant status and consequently, assisted in repairing the DNA damage and mitochondrial function. Further, the expression of hypertrophic markers in the DOX treated cardiomyocytes reconciled the expression factors both at the transcriptional and translational levels after Gg treatment. SIRT-1 mediated pathway and its downstream activator PPARs are significant in maintaining the cellular functions. It was observed that the Gg extract allows regaining the nuclear SIRT-1 and PPAR-? level which was otherwise reduced with DOX treatment in H9c2 cardiomyocytes. The co-immunoprecipitation (Co-IP) documented that SIRT-1 interacts with PPAR-? in the untreated control H9c2 cardiomyocytes whereas DOX treatment interferes and diminishes this interaction however the Gg treatment maintains this interaction. Knocking down SIRT-1 also downregulated expression of PPAR-? and PPAR-? in DOX treated cells and Gg treatment was able to enhance the expression of PPAR-? and PPAR-? in SIRT-1 knocked down cardiomyocytes. Conclusions: The antioxidant property of Gg defend the cardiac cells against the DOX induced toxicity via; 1) reducing the oxidative stress, 2) maintaining the mitochondrial functions, 3) regulating lipid homeostasis and cardiac metabolism through SIRT-1 pathway, and 4) conserving the cardiac hypertrophy and hence preserving the cardiomyocytes health. Therefore, Gg can be recommended as a healthy supplement with DOX towards cancer therapeutics associated cardiotoxicity. - 2020