Dataset Information

Oxidative Stress-Induced Afterdepolarizations and Protein Kinase C Signaling.

ABSTRACT:

Background

Hydrogen peroxide (H?O?)-induced oxidative stress has been demonstrated to induce afterdepolarizations and triggered activities in isolated myocytes, but the underlying mechanisms remain not fully understood. We aimed to explore whether protein kinase C (PKC) activation plays an important role in oxidative stress-induced afterdepolarizations.

Methods

Action potentials and ion currents of isolated rabbit cardiomyocytes were recorded using the patch clamp technique. H?O? (1 mM) was perfused to induce oxidative stress and the specific classical PKC inhibitor, Gö 6983 (1 ?M), was applied to test the involvement of PKC.

Results

H?O? perfusion prolonged the action potential duration and induced afterdepolarizations. Pretreatment with Gö 6983 prevented the emergence of H?O?-induced afterdepolarizations. Additional application of Gö 6983 with H?O? effectively suppressed H?O?-induced afterdepolarizations. H?O? increased the late sodium current (I_Na,L) (n = 7, p < 0.01) and the L-type calcium current (I_Ca,L) (n = 5, p < 0.01), which were significantly reversed by Gö 6983 (p < 0.01). H?O? also increased the transient outward potassium current (I_to) (n = 6, p < 0.05). However, Gö 6983 showed little effect on H?O?-induced enhancement of I_to.

Conclusions

H?O? induced afterdepolarizations via the activation of PKC and the enhancement of I_Ca,L and I_Na,L. These results provide evidence of a link between oxidative stress, PKC activation and afterdepolarizations.

SUBMITTER: Fei YD

PROVIDER: S-EPMC5412274 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Oxidative Stress-Induced Afterdepolarizations and Protein Kinase C Signaling.

Fei Yu-Dong YD Li Wei W Hou Jian-Wen JW Guo Kai K Chen Xiao-Meng XM Chen Yi-He YH Wang Qian Q Xu Xiao-Lei XL Wang Yue-Peng YP Li Yi-Gang YG

International journal of molecular sciences 20170330 4

<h4>Background</h4>Hydrogen peroxide (H₂O₂)-induced oxidative stress has been demonstrated to induce afterdepolarizations and triggered activities in isolated myocytes, but the underlying mechanisms remain not fully understood. We aimed to explore whether protein kinase C (PKC) activation plays an important role in oxidative stress-induced afterdepolarizations.<h4>Methods</h4>Action potentials and ion currents of isolated rabbit cardiomyocytes were recorded using the patch clamp technique. H₂O₂ ...[more]

PMID: 28358314

Similar Datasets

Project description:Vascular oxidative stress and inflammation play an important role in angiotensin II-induced hypertension, and mitogen-activated protein kinases participate in these processes. We questioned whether mitogen-activated protein kinase-activated protein kinase 2 (MK2), a downstream target of p38 mitogen-activated protein kinase, is involved in angiotensin II-induced vascular responses. In vivo experiments were performed in wild-type and Mk2 knockout mice infused intravenously with angiotensin II. Angiotensin II induced a 30 mm Hg increase in mean blood pressure in wild-type that was delayed in Mk2 knockout mice. Angiotensin II increased superoxide production and vascular cell adhesion molecule-1 in blood vessels of wild-type but not in Mk2 knockout mice. Mk2 knockdown by small interfering RNA in mouse mesenteric vascular smooth muscle cells caused a 42% reduction in MK2 protein and blunted the angiotensin II-induced 40% increase of MK2 expression. Mk2 knockdown blunted angiotensin II-induced doubling of intracellular adhesion molecule-1 expression, 2.4-fold increase of nuclear p65, and 1.4-fold increase in Ets-1. Mk2 knockdown abrogated the angiotensin II-induced 4.7-fold and 1.3-fold increase of monocyte chemoattractant protein-1 mRNA and protein. Angiotensin II enhanced reactive oxygen species levels (by 29%) and nicotinamide adenine dinucleotide phosphate oxidase activity (by 48%), both abolished by Mk2 knockdown. Reduction of MK2 blocked angiotensin II-induced p47phox translocation to the membrane, associated with a 53% enhanced catalase expression. Angiotensin II-induced increase of MK2 was prevented by the nicotinamide adenine dinucleotide phosphate oxidase inhibitor Nox2ds-tat. Mk2 small interfering RNA prevented the angiotensin II-induced 30% increase of proliferation. In conclusion, MK2 plays a critical role in angiotensin II signaling, leading to hypertension, oxidative stress via activation of p47phox and inhibition of antioxidants, and vascular inflammation and proliferation.

Project description:We previously demonstrated that protein kinase C? (PKC?; PKC delta) is an oxidative stress-sensitive kinase that plays a causal role in apoptotic cell death in neuronal cells. Although PKC? activation has been extensively studied, relatively little is known about the molecular mechanisms controlling PKC? expression. To characterize the regulation of PKC? expression, we cloned an ?2-kbp 5'-promoter segment of the mouse Prkcd gene. Deletion analysis indicated that the noncoding exon 1 region contained multiple Sp sites, including four GC boxes and one CACCC box, which directed the highest levels of transcription in neuronal cells. In addition, an upstream regulatory region containing adjacent repressive and anti-repressive elements with opposing regulatory activities was identified within the region -712 to -560. Detailed mutagenesis studies revealed that each Sp site made a positive contribution to PKC? promoter expression. Overexpression of Sp family proteins markedly stimulated PKC? promoter activity without any synergistic transactivating effect. Furthermore, experiments in Sp-deficient SL2 cells indicated long isoform Sp3 as the essential activator of PKC? transcription. Importantly, both PKC? promoter activity and endogenous PKC? expression in NIE115 cells and primary striatal cultures were inhibited by mithramycin A. The results from chromatin immunoprecipitation and gel shift assays further confirmed the functional binding of Sp proteins to the PKC? promoter. Additionally, we demonstrated that overexpression of p300 or CREB-binding protein increases the PKC? promoter activity. This stimulatory effect requires intact Sp-binding sites and is independent of p300 histone acetyltransferase activity. Finally, modulation of Sp transcriptional activity or protein level profoundly altered the cell death induced by oxidative insult, demonstrating the functional significance of Sp-dependent PKC? gene expression. Collectively, our findings may have implications for development of new translational strategies against oxidative damage.

Dataset Information

Oxidative Stress-Induced Afterdepolarizations and Protein Kinase C Signaling.

Background

Methods

Results

Conclusions

Publications

Oxidative Stress-Induced Afterdepolarizations and Protein Kinase C Signaling.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets