scholarly journals Taurine Protects Primary Neonatal Cardiomyocytes Against Apoptosis Induced by Hydrogen Peroxide

2018 ◽  
Vol 59 (1) ◽  
pp. 190-196 ◽  
Author(s):  
Junnan Wang ◽  
Chao Qi ◽  
Lulu Liu ◽  
Lijing Zhao ◽  
Wenzhang Cui ◽  
...  
Author(s):  
Xinyu Feng ◽  
Shanjie Wang ◽  
Xingjun Yang ◽  
Jie Lin ◽  
Wanrong Man ◽  
...  

The disruption of mitochondrial dynamics is responsible for the development of diabetic cardiomyopathy (DCM). However, the mechanisms that regulate the balance of mitochondrial fission and fusion are not well-understood. Wild-type, Mst1 transgenic and Mst1 knockout mice were induced with experimental diabetes by streptozotocin injection. In addition, primary neonatal cardiomyocytes were isolated and cultured to simulate diabetes to explore the mechanisms. Echocardiograms and hemodynamic measurements revealed that Mst1 knockout alleviated left ventricular remodeling and cardiac dysfunction in diabetic mice. Mst1 knockdown significantly decreased the number of TUNEL-positive cardiomyocytes subjected to high-glucose (HG) medium culture. Immunofluorescence study indicated that Mst1 overexpression enhanced, while Mst1 knockdown mitigated mitochondrial fission in DCM. Mst1 participated in the regulation of mitochondrial fission by upregulating the expression of Drp1, activating Drp1S616 phosphorylation and Drp1S637 dephosphorylation, as well as promoting Drp1 recruitment to the mitochondria. Furthermore, Drp1 knockdown abolished the effects of Mst1 on mitochondrial fission, mitochondrial membrane potential and mitochondrial dysfunction in cardiomyocytes subjected to HG treatment. These results indicated that Mst1 knockout inhibits mitochondrial fission and alleviates left ventricular remodeling thus prevents the development of DCM.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Sumit Kar ◽  
Hamid Shahshahan ◽  
Paras K Mishra

Hyperglycemia-induced death of terminally differentiated cardiomyocytes in diabetic cardiomyopathy (DMCM) leads to heart failure. Ferroptosis is a newly discovered form of cell death triggered by intracellular iron and oxidative stress. While little is known about ferroptosis in DMCM, hyperinsulinemia stimulates intracellular iron uptake, which would be predicted to increase ferroptosis. H 2 S is an endogenous gaseous signaling molecule which may inhibit ferroptosis. H 2 S donors increase glutathione substrate for glutathione peroxidase 4 (GPX4), which removes lipid peroxidation and is the primary inhibitor of ferroptosis. However, no study has investigated the role of H 2 S in ferroptosis. We tested the hypothesis that increased ferroptosis contributes to DMCM, which is ameliorated by restoring H 2 S levels, by measuring ferroptosis in the hearts of db/db mice with DMCM and high glucose treated primary neonatal cardiomyocytes after H 2 S donor treatment. GPX4 expression was decreased (3.21±0.41 GPX4/total protein in db/+ control mice vs. 1.84±0.26 in db/db, P<0.05, n=6/group) and 4-HNE lipid peroxide was increased (7.37±0.98 μg 4-HNE/total protein in db/+ control mice vs. 8.73±0.84 in db/db, P<0.05, n=3/group) in the left ventricle of db/db mice indicating increased ferroptosis in DMCM. GPX4 activity was also decreased along with increased 4-HNE in high glucose cultured cardiomyocytes. Treatment with the ferroptosis inhibitor ferrostatin-1 prevented hyperglycemia induced ferroptosis. Treatment of cardiomyocytes with the H 2 S donor GYY4137 in hyperglycemia also decreased 4-HNE. We also validated the anti-ferroptotic potential of H 2 S by treating cardiomyocytes with the ferroptosis inducer RSL3 and GYY4137. H 2 S donor treatment reduced reactive oxygen species and 4-HNE lipid peroxide seen after ferroptosis induction with RSL3. This study establishes ferroptosis as a new, non-apoptotic, form of cell death in DMCM, and H 2 S as a novel regulator of cardiac ferroptosis.


Author(s):  
George E. Childs ◽  
Joseph H. Miller

Biochemical and differential centrifugation studies have demonstrated that the oxidative enzymes of Acanthamoeba sp. are localized in mitochondria and peroxisomes (microbodies). Although hartmanellid amoebae have been the subject of several electron microscopic studies, peroxisomes have not been described from these organisms or other protozoa. Cytochemical tests employing diaminobenzidine-tetra HCl (DAB) and hydrogen peroxide were used for the ultrastructural localization of peroxidases of trophozoites of Hartmanella sp. (A-l, Culbertson), a pathogenic strain grown in axenic cultures of trypticase soy broth.


2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light &gt;600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.


2010 ◽  
Vol 34 (8) ◽  
pp. S27-S27
Author(s):  
Xueling Dai ◽  
Ping Chang ◽  
Ke Xu ◽  
Changjun Lin ◽  
Hanchang Huang ◽  
...  

2020 ◽  
Vol 48 (2) ◽  
pp. 613-620
Author(s):  
Clara Ortegón Salas ◽  
Katharina Schneider ◽  
Christopher Horst Lillig ◽  
Manuela Gellert

Processing of and responding to various signals is an essential cellular function that influences survival, homeostasis, development, and cell death. Extra- or intracellular signals are perceived via specific receptors and transduced in a particular signalling pathway that results in a precise response. Reversible post-translational redox modifications of cysteinyl and methionyl residues have been characterised in countless signal transduction pathways. Due to the low reactivity of most sulfur-containing amino acid side chains with hydrogen peroxide, for instance, and also to ensure specificity, redox signalling requires catalysis, just like phosphorylation signalling requires kinases and phosphatases. While reducing enzymes of both cysteinyl- and methionyl-derivates have been characterised in great detail before, the discovery and characterisation of MICAL proteins evinced the first examples of specific oxidases in signal transduction. This article provides an overview of the functions of MICAL proteins in the redox regulation of cellular functions.


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