α-Crystallin B prevents apoptosis after H2O2 exposure in mouse neonatal cardiomyocytes

α-Crystallin B (cryAB) is the most abundant small heat shock protein in cardiomyocytes (CMs) and has been shown to have potent antiapoptotic properties. Because the mechanism by which cryAB prevents apoptosis has not been fully characterized, we examined its protective effects at the cellular level by silencing cryAB in mouse neonatal CMs using lentivector-mediated transduction of short hairpin RNAs. Subcellular fractionation of whole hearts showed that cryAB is cytosolic under control conditions, and after H2O2 exposure, it translocates to the mitochondria. Phosphorylated cryAB (PcryAB) is mainly associated with the mitochondria, and any residual cytosolic PcryAB translocates to the mitochondria after H2O2 exposure. H2O2 exposure caused increases in cryAB and PcryAB levels, and cryAB silencing resulted in increased levels of apoptosis after exposure to H2O2. Coimmunoprecipitation assays revealed an apparent interaction of both cryAB and PcryAB with mitochondrial voltage-dependent anion channels (VDAC), translocase of outer mitochondrial membranes 20 kDa (TOM 20), caspase 3, and caspase 12 in mouse cardiac tissue. Our results are consistent with the conclusion that the cardioprotective effects of cryAB are mediated by its translocation from the cytosol to the mitochondria under conditions of oxidative stress and that cryAB interactions with VDAC, TOM 20, caspase 3, and caspase 12 may be part of its protective mechanism.

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Protective efficacy of carnosic acid against hydrogen peroxide induced oxidative injury in HepG2 cells through the SIRT1 pathway

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2014-0513 ◽

2015 ◽

Vol 93 (8) ◽

pp. 625-631 ◽

Cited By ~ 8

Author(s):

Yan Hu ◽

Ning Zhang ◽

Qing Fan ◽

Musen Lin ◽

Ce Zhang ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Hepg2 Cells ◽

Manganese Superoxide Dismutase ◽

Caspase 3 ◽

Protective Efficacy ◽

B Cell Lymphoma ◽

Sirtuin 1 ◽

Carnosic Acid ◽

Protective Effects ◽

Hepatocyte Damage

Carnosic acid (CA), found in rosemary, has been reported to have antioxidant and antiadipogenic properties. Here, we investigate the molecular mechanism by which CA inhibits hydrogen peroxide (H2O2)-induced injury in HepG2 cells. Cells were pretreated with 2.5–10 μmol/L CA for 2 h and then exposed to 3 mmol/L H2O2 for an additional 4 h. CA dose-dependently increased cell viability and decreased lactate dehydrogenase activities. Pretreatment with CA completely attenuated the inhibited expression of manganese superoxide dismutase (MnSOD) and the B-cell lymphoma-extra large (Bcl-xL), and reduced glutathione activity caused by H2O2, whereas it reversed reactive oxygen species accumulation and the increase in cleaved caspase-3. Importantly, sirtuin 1 (SIRT1), a NAD+-dependent deacetylase, was significantly increased by CA. Considering the above results, we hypothesized that SIRT1 may play important roles in the protective effects of CA in injury induced by H2O2. As expected, SIRT1 suppression by Ex527 (6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide) and siRNA-mediated SIRT1 silencing (si-SIRT1) significantly aggravated the H2O2-induced increased level of cleaved caspase-3 but greatly reduced the decreased expression of MnSOD and Bcl-xL. Furthermore, the positive regulatory effect of CA was inhibited by si-SIRT1. Collectively, the present study indicated that CA can alleviate H2O2-induced hepatocyte damage through the SIRT1 pathway.

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Abstract 51: Thymosin β4 Targets Wisp1 to Protect Cardiomyocytes in AngII- induced Cardiac Hypertrophy

Circulation Research ◽

10.1161/res.117.suppl_1.51 ◽

2015 ◽

Vol 117 (suppl_1) ◽

Author(s):

Sudhiranjan Gupta ◽

Li Li ◽

Rakesh Guleria ◽

Kenneth M Baker

Keyword(s):

Cardiac Hypertrophy ◽

Fluorescent Microscopy ◽

Marker Genes ◽

Protective Mechanism ◽

Ang Ii ◽

Hypertrophic Response ◽

Antiapoptotic Proteins ◽

Neonatal Cardiomyocytes ◽

Cell Proliferation And Differentiation ◽

Pre Treatment

Background: Thymosin beta-4 (Tβ4) is a ubiquitous protein with many properties relating to cell proliferation and differentiation that promotes wound healing and modulates inflammatory mediators. However, the role of Tβ4 in cardiomyocytes hypertrophy is currently unknown. The purpose of this study is to dissect the cardio-protective mechanism of Tβ4 in Ang II induced cardiac hypertrophy. Methods: Rat neonatal cardiomyocytes with or without Tβ4 pretreatment were stimulated with Ang II and expression of cell sizes, hypertrophy marker genes and Wnt signaling components was evaluated by quantitative real-time PCR, western blotting and fluorescent microscopy. Selected target gene Wisp-1 was either overexpressed or silenced by siRNA transfections in neonatal cardiomyocytes and effect of Tβ4 in Ang II-induced cardiac hypertrophy was evaluated. Results: Pre-treatment of Tβ4 resulted in reduction of cell sizes, hypertrophy marker genes and WNT-associated gene expression and levels induced by Ang II in cardiomyocytes. Tβ4 pretreatment also resulted in an increase in the expression of antiapoptotic proteins and reduction of Bax/BCl 2 ratio in the cardiomyocytes. Wisp-1 overexpression promotes cardiac hypertrophy and was reversed by pretreatment with Tβ4. Knocking down of Wisp1 partly rescue the cells from hypertrophic response after Tβ4 treatment. Conclusion: This is the first report that demonstrates the effect of Tβ4 on cardiomyocytes hypertrophy and its capability to selectively target Wisp-1 in neonatal cardiomyocytes thus preventing cell death, thereby, protecting the myocardium. Wisp-1 promotes the cardiac hypertrophy which was prevented by Tβ4 treatment.

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The impact of Keap1/Nrf2, P38MAPK/NF-κB and Bax/Bcl2/caspase-3 signaling pathways in the protective effects of berberine against methotrexate-induced nephrotoxicity

Biomedicine & Pharmacotherapy ◽

10.1016/j.biopha.2018.10.088 ◽

2019 ◽

Vol 109 ◽

pp. 47-56 ◽

Cited By ~ 14

Author(s):

Emad H.M. Hassanein ◽

Abdel-Gawad S. Shalkami ◽

Marwa M. Khalaf ◽

Wafaa R. Mohamed ◽

Ramadan A.M. Hemeida

Keyword(s):

Signaling Pathways ◽

Caspase 3 ◽

Protective Effects ◽

The Impact

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PROTECTIVE EFFECTS OF DEBO ON SERUM-DEPRIVED APOPTOSIS OF PC12 CELLS VIA INHIBITION OF H2O2GENERATION AND CASPASE 3-LIKE PROTEASE ACTIVITY

Immunopharmacology and Immunotoxicology ◽

10.1081/iph-120003753 ◽

2002 ◽

Vol 24 (2) ◽

pp. 227-243 ◽

Cited By ~ 1

Author(s):

Jienny Lee ◽

Myung-Sunny Kim ◽

Channy Park ◽

Yun-Sook Lim ◽

In Lee ◽

...

Keyword(s):

Pc12 Cells ◽

Protease Activity ◽

Caspase 3 ◽

Protective Effects

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Hexarelin protects rat cardiomyocytes from angiotensin II-induced apoptosis in vitro

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00648.2003 ◽

2004 ◽

Vol 286 (3) ◽

pp. H1063-H1069 ◽

Cited By ~ 43

Author(s):

Jin-Jiang Pang ◽

Rong-Kun Xu ◽

Xiang-Bin Xu ◽

Ji-Min Cao ◽

Chao Ni ◽

...

Keyword(s):

Heart Failure ◽

Angiotensin Ii ◽

Caspase 3 ◽

Cardiomyocyte Apoptosis ◽

Protective Effects ◽

Ang Ii ◽

Growth Hormone Secretagogue Receptor ◽

Growth Hormone Secretagogue ◽

Rat Cardiomyocytes ◽

Induced Apoptosis

Loss of cardiomyocytes by apoptosis is proposed to cause heart failure. Angiotensin II (ANG II), an important neurohormonal factor during heart failure, can induce cardiomyocyte apoptosis. Inasmuch as hexarelin has been reported to have protective effects in this process, we examined whether hexarelin can prevent cardiomyocytes from ANG II-induced cell death. Cultured cardiomyocytes from neonatal rats were stimulated with ANG II. Apoptosis was evaluated using fluorescence microscopy, TdT-mediated dUTP nick-end labeling (TUNEL) method, flow cytometry, DNA laddering, and analysis of cell viability by (3,4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). It was found that incubation with 0.1 μmol/l ANG II for 48 h increased cardiomyocyte apoptosis. Administration of 0.1 μmol/l hexarelin significantly decreased this ANG II-induced apoptosis and DNA fragmentation and increased myocyte viability. To further investigate the underlying mechanisms, caspase-3 activity assay and mRNA expression of Bax, Bcl-2, and growth hormone secretagogue receptor (GHS-R; the supposed hexarelin binding site) were examined. GHS-R mRNA was abundantly expressed in cardiomyocytes and was upregulated after administration of hexarelin. These results suggest that hexarelin abates cardiomyocytes from ANG II-induced apoptosis possibly via inhibiting the increased caspase-3 activity and Bax expression induced by ANG II and by increasing the expression of Bcl-2, which is depressed by ANG II. Whether the upregulated expression of GHS-R induced by hexarelin is associated with this antiapoptotic effect deserves further investigation.

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Protective Effects of HBSP on Ischemia Reperfusion and Cyclosporine A Induced Renal Injury

Clinical and Developmental Immunology ◽

10.1155/2013/758159 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 7

Author(s):

Yuanyuan Wu ◽

Junlin Zhang ◽

Feng Liu ◽

Cheng Yang ◽

Yufang Zhang ◽

...

Keyword(s):

Cyclosporine A ◽

Caspase 3 ◽

Interstitial Fibrosis ◽

Ischemia Reperfusion ◽

Inflammatory Cells ◽

Protective Effects ◽

Tubulointerstitial Damage ◽

Apoptosis And Inflammation ◽

The Right ◽

Active Caspase

Ischemia reperfusion (IR) and cyclosporine A (CsA) injuries are unavoidable in kidney transplantation and are associated with allograft dysfunction. Herein, the effect and mechanism of a novel tissue protective peptide, helix B surface peptide (HBSP) derived from erythropoietin, were investigated in a rat model. The right kidney was subjected to 45 min ischemia, followed by left nephrectomy and 2-week reperfusion, with or without daily treatment of CsA 25 mg/kg and/or HBSP 8 nmol/kg. Blood urea nitrogen was increased by CsA but decreased by HBSP at 1 week and 2 weeks, while the same changes were revealed in urinary protein/creatinine only at 2 weeks. HBSP also significantly ameliorated tubulointerstitial damage and interstitial fibrosis, which were gradually increased by IR and CsA. In addition, apoptotic cells, infiltrated inflammatory cells, and active caspase-3+ cells were greatly reduced by HBSP in the both IR and IR + CsA groups. The 17 kD active caspase-3 protein was decreased by HBSP in the IR and IR + CsA kidneys, with decreased mRNA only in the IR + CsA kidneys. Taken together, it has been demonstrated, for the first time, that HBSP effectively improved renal function and tissue damage caused by IR and/or CsA, which might be through reducing caspase-3 activation and synthesis, apoptosis, and inflammation.

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Paracrine control of α-cell glucagon exocytosis is compromised in human type-2 diabetes

10.1101/789545 ◽

2019 ◽

Author(s):

Muhmmad Omar-Hmeadi ◽

Per-Eric Lund ◽

Nikhil R Gandasi ◽

Anders Tengholm ◽

Sebastian Barg

Keyword(s):

Type 2 Diabetes ◽

Glucagon Secretion ◽

Cellular Level ◽

Membrane Excitability ◽

Granule Exocytosis ◽

Paracrine Effects ◽

Voltage Dependent ◽

Resolution Imaging ◽

Glucose Sensitivity

AbstractGlucagon is secreted from pancreatic α-cells to activate gluconeogenesis and other pathways that raise blood glucose during hypoglycemia. Glucose-dependent regulation of glucagon secretion involves both α-cell-intrinsic mechanisms and paracrine control through insulin and somatostatin. In type-2 diabetes (T2D) inadequately high glucagon levels contribute to hyperglycemia. To understand these disease-associated changes at the cellular level, and to isolate intrinsic and paracrine effects, we analyzed glucagon granule exocytosis and membrane excitability in isolated α-cells from 56 non-diabetic (ND) and 15 T2D human donors. High resolution imaging showed that glucagon granule exocytosis had a U-shaped sensitivity to glucose, with the slowest rate around 7 mM glucose, and accelerated rates at <5 and >10 mM glucose. Exocytosis was reduced in T2D α-cells, but their glucose sensitivity remained intact and there were no changes in voltage-dependent ion currents or granule trafficking. Instead, α-cells from T2D donors were markedly insensitive to somatostatin and insulin, which rapidly inhibited exocytosis and electrical activity in ND cells. Thus, intrinsic mechanisms do not inhibit glucagon secretion at hyperglycemia, and elevated glucagon levels in human T2D reflect an insensitivity of α-cells to paracrine inhibition.

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Dapagliflozin Alleviates Myocardial Inflammation by Regulating the Macrophage Polarization and Stat3-related Pathways in Coxsackie Virus B3-induced Acute Viral Myocarditis

10.21203/rs.3.rs-1200173/v1 ◽

2022 ◽

Author(s):

Pengcheng Yan ◽

Xiaoning Song ◽

Joanne Tran ◽

Runfa Zhou ◽

Xinran Cao ◽

...

Keyword(s):

Cardiac Tissue ◽

Inflammatory Diseases ◽

Macrophage Polarization ◽

Viral Myocarditis ◽

Coxsackie Virus ◽

Myocardial Inflammation ◽

Protective Effects ◽

Acute Viral Myocarditis ◽

Cvb3 Infection ◽

Coxsackie Virus B3

Abstract Viral myocarditis (VMC), which is most prevalently caused by Coxsackievirus B3 (CVB3) infection, is a serious clinical condition characterized by cardiac inflammation. Dapagliflozin, a kind of sodium glucose co-transporters 2(SGLT-2) inhibitor, exhibited protective effects on plenty of inflammatory diseases, while its effect on viral myocarditis has not been studied. Recently we found the protective effect of dapagliflozin on VMC. After CVB3 infection, dapagliflozin were given orally to Balb/c male mice for 8 days and then the severity of myocarditis was assessed. Our results indicated that dapagliflozin significantly alleviated the severity of viral myocarditis, elevated the survival rate, and ameliorated cardiac function. Besides, dapagliflozin can decrease the level of proinflammatory cytokines included IL-1β, IL-6, TNF-α. Furthermore, dapagliflozin can inhibit macrophages differentiate to classically activated macrophages (M1) in cardiac tissue and activate the Stat3 signal pathway which is reported to promote polarization of the alternatively activated macrophage (M2). In conclusion, our study demonstrates that dapagliflozin alleviates myocardial inflammation by regulating the macrophage polarization and Stat3-related pathways in coxsackie virus B3-induced acute viral myocarditis.

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Zfhx3 Transcription Factor Represses the Expression of SCN5A Gene and Decreases Sodium Current Density (INa)

International Journal of Molecular Sciences ◽

10.3390/ijms222313031 ◽

2021 ◽

Vol 22 (23) ◽

pp. 13031

Author(s):

Marcos Rubio-Alarcón ◽

Anabel Cámara-Checa ◽

María Dago ◽

Teresa Crespo-García ◽

Paloma Nieto-Marín ◽

...

Keyword(s):

Transcription Factor ◽

Cardiac Tissue ◽

Sodium Current ◽

Na Channel ◽

Ubiquitin Protein Ligase ◽

Endogenous Expression ◽

Voltage Dependent ◽

Familial Atrial Fibrillation ◽

Cardiac Excitability ◽

Scn5a Gene

The ZFHX3 and SCN5A genes encode the zinc finger homeobox 3 (Zfhx3) transcription factor (TF) and the human cardiac Na+ channel (Nav1.5), respectively. The effects of Zfhx3 on the expression of the Nav1.5 channel, and in cardiac excitability, are currently unknown. Additionally, we identified three Zfhx3 variants in probands diagnosed with familial atrial fibrillation (p.M1260T) and Brugada Syndrome (p.V949I and p.Q2564R). Here, we analyzed the effects of native (WT) and mutated Zfhx3 on Na+ current (INa) recorded in HL-1 cardiomyocytes. ZFHX3 mRNA can be detected in human atrial and ventricular samples. In HL-1 cardiomyocytes, transfection of Zfhx3 strongly reduced peak INa density, while the silencing of endogenous expression augmented it (from −65.9 ± 8.9 to −104.6 ± 10.8 pA/pF; n ≥ 8, p < 0.05). Zfhx3 significantly reduced the transcriptional activity of human SCN5A, PITX2, TBX5, and NKX25 minimal promoters. Consequently, the mRNA and/or protein expression levels of Nav1.5 and Tbx5 were diminished (n ≥ 6, p < 0.05). Zfhx3 also increased the expression of Nedd4-2 ubiquitin-protein ligase, enhancing Nav1.5 proteasomal degradation. p.V949I, p.M1260T, and p.Q2564R Zfhx3 produced similar effects on INa density and time- and voltage-dependent properties in WT. WT Zfhx3 inhibits INa as a result of a direct repressor effect on the SCN5A promoter, the modulation of Tbx5 increasing on the INa, and the increased expression of Nedd4-2. We propose that this TF participates in the control of cardiac excitability in human adult cardiac tissue.

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Non-ohmic tissue conduction in cardiac electrophysiology: upscaling the non-linear voltage-dependent conductance of gap junctions

10.1101/690255 ◽

2019 ◽

Author(s):

Daniel E. Hurtado ◽

Javiera Jilberto ◽

Grigory Panasenko

Keyword(s):

Computational Complexity ◽

Gap Junctions ◽

Cardiac Tissue ◽

Tissue Level ◽

Cardiac Conduction ◽

Non Linear ◽

Voltage Dependent ◽

Junctional Coupling ◽

Organ Level ◽

Electrical Propagation

AbstractGap junctions are key mediators of the intercellular communication in cardiac tissue, and their function is vital to sustain normal cardiac electrical activity. Conduction through gap junctions strongly depends on the hemichannel arrangement and transjunctional voltage, rendering the intercellular conductance highly non-Ohmic. Despite this marked non-linear behavior, current tissue-level models of cardiac conduction are rooted on the assumption that gap-junctions conductance is constant (Ohmic), which results in inaccurate predictions of electrical propagation, particularly in the low junctional-coupling regime observed under pathological conditions. In this work, we present a novel non-Ohmic multiscale (NOM) model of cardiac conduction that is suitable for tissue-level simulations. Using non-linear homogenization theory, we develop a conductivity model that seamlessly upscales the voltage-dependent conductance of gap junctions, without the need of explicitly modeling gap junctions. The NOM model allows for the simulation of electrical propagation in tissue-level cardiac domains that accurately resemble that of cell-based microscopic models for a wide range of junctional coupling scenarios, recovering key conduction features at a fraction of the computational complexity. A unique feature of the NOM model is the possibility of upscaling the response of non-symmetric gap-junction conductance distributions, which result in conduction velocities that strongly depend on the direction of propagation, thus allowing to model the normal and retrograde conduction observed in certain regions of the heart. We envision that the NOM model will enable organ-level simulations that are informed by sub- and inter-cellular mechanisms, delivering an accurate and predictive in-silico tool for understanding the heart function.Author summaryThe heart relies on the propagation of electrical impulses that are mediated gap junctions, whose conduction properties vary depending on the transjunctional voltage. Despite this non-linear feature, current mathematical models assume that cardiac tissue behaves like an Ohmic (linear) material, thus delivering inaccurate results when simulated in a computer. Here we present a novel mathematical multiscale model that explicitly includes the non-Ohmic response of gap junctions in its predictions. Our results show that the proposed model recovers important conduction features modulated by gap junctions at a fraction of the computational complexity. This contribution represents an important step towards constructing computer models of a whole heart that can predict organ-level behavior in reasonable computing times.

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