scholarly journals Calpain-2 Specifically Cleaves Junctophilin-2 at the Same Site as Calpain-1 but with Less Efficacy

2021 ◽  
Author(s):  
Jinxi Wang ◽  
Grace Ciampa ◽  
Dong Zheng ◽  
Qian Shi ◽  
Biyi Chen ◽  
...  

Calpain proteolysis contributes to the pathogenesis of heart failure but the calpain isoforms responsible and their substrate specificities have not been rigorously defined. One substrate, Junctophilin-2 (JP2), is essential for maintaining excitation-contraction coupling. We previously demonstrated that JP2 is cleaved by calpain-1 (CAPN1) between Arginine 565 (R565) and Threonine 566 (T566). Recently, calpain-2 (CAPN2) was reported to cleave JP2 at a novel site between Glycine 482 (G482) and Threonine 483 (T483). We aimed to directly compare the contributions of each calpain isoform, their Ca2+ sensitivity, and their cleavage site selection for JP2. We find CAPN1, CAPN2 and their requisite CAPNS1 regulatory subunit are induced by pressure overload stress that is concurrent with JP2 cleavage. Using in vitro calpain cleavage assays, we demonstrate that CAPN1 and CAPN2 cleave JP2 into similar 75-kD N-terminal (JP2NT) and 25-kD C-terminal fragments (JP2CT) with CAPNS1 co-expression enhancing proteolysis. Deletion mutagenesis shows both CAPN1 and CAPN2 require R565/T566 but not G482/T483. When heterologously expressed, the JP2CT peptide corresponding to R565/T566 cleavage approximates the 25-kD species found during cardiac stress while the C-terminal peptide from potential cleavage at G482/T483 produces a 35-kD product. Similar results were obtained for human JP2. Finally, we show that CAPN1 has higher Ca2+ sensitivity and cleavage efficacy than CAPN2 on JP2 and other cardiac substrates including cTnT, cTnI and β2-spectrin. We conclude that CAPN2 cleaves JP2 at the same functionally conserved R565/T566 site as CAPN1 but with less efficacy and suggest heart failure may be targeted through specific inhibition of CAPN1.

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Andrea Iorga ◽  
Rangarajan Nadadur ◽  
Salil Sharma ◽  
Jingyuan Li ◽  
Mansoureh Eghbali

Heart failure is generally characterized by increased fibrosis and inflammation, which leads to functional and contractile defects. We have previously shown that short-term estrogen (E2) treatment can rescue pressure overload-induced decompensated heart failure (HF) in mice. Here, we investigate the anti-inflammatory and anti-fibrotic effects of E2 on reversing the adverse remodeling of the left ventricle which occurs during the progression to heart failure. Trans-aortic constriction procedure was used to induce HF. Once the ejection fraction reached ∼30%, one group of mice was sacrificed and the other group was treated with E2 (30 αg/kg/day) for 10 days. In vitro, co-cultured neonatal rat ventricular myocytes and fibroblasts were treated with Angiotensin II (AngII) to simulate cardiac stress, both in the presence or absence of E2. In vivo RT-PCR showed that the transcript levels of the pro-fibrotic markers Collagen I, TGFβ, Fibrosin 1 (FBRS) and Lysil Oxidase (LOX) were significantly upregulated in HF (from 1.00±0.16 to 1.83±0.11 for Collagen 1, 1±0.86 to 4.33±0.59 for TGFβ, 1±0.52 to 3.61±0.22 for FBRS and 1.00±0.33 to 2.88±0.32 for LOX) and were reduced with E2 treatment to levels similar to CTRL. E2 also restored in vitro AngII-induced upregulation of LOX, TGFβ and Collagen 1 (LOX:1±0.23 in CTRL, 6.87±0.26 in AngII and 2.80±1.5 in AngII+E2; TGFβ: 1±0.08 in CTRL, 3.30±0.25 in AngII and 1.59±0.21 in AngII+E2; Collagen 1: 1±0.05 in CTRL.2±0.01 in AngII and 0.65±0.02 (p<0.05, values normalized to CTRL)). Furthermore, the pro-inflammatory interleukins IL-1β and IL-6 were upregulated from 1±0.19 to 1.90±0.09 and 1±0.30 to 5.29±0.77 in the in vivo model of HF, respectively, and reversed to CTRL levels with E2 therapy. In vitro, IL-1β was also significantly increased ∼ 4 fold from 1±0.63 in CTRL to 3.86±0.14 with AngII treatment and restored to 1.29±0.77 with Ang+E2 treatment. Lastly, the anti-inflammatory interleukin IL-10 was downregulated from 1.00±0.17 to 0.49±0.03 in HF and reversed to 0.67±0.09 in vivo with E2 therapy (all values normalized to CTRL). This data strongly suggests that one of the mechanisms for the beneficial action of estrogen on left ventricular heart failure is through reversal of inflammation and fibrosis.


2018 ◽  
Vol 125 (1) ◽  
pp. 86-96 ◽  
Author(s):  
T. Dylan Olver ◽  
Jenna C. Edwards ◽  
Brian S. Ferguson ◽  
Jessica A. Hiemstra ◽  
Pamela K. Thorne ◽  
...  

Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Thus, the purpose of this study was to determine the therapeutic efficacy of chronic interval exercise training (IT) on large-conductance Ca2+-activated K+ (BKCa) channel-mediated coronary vascular function in heart failure. We hypothesized that chronic interval exercise training would attenuate pressure overload-induced impairments to coronary BKCa channel-mediated function. A translational large-animal model with cardiac features of HFpEF was used to test this hypothesis. Specifically, male Yucatan miniswine were divided into three groups ( n = 7/group): control (CON), aortic banded (AB)-heart failure (HF), and AB-interval trained (HF-IT). Coronary blood flow, vascular conductance, and vasodilatory capacity were measured after administration of the BKCa channel agonist NS-1619 both in vivo and in vitro in the left anterior descending coronary artery and isolated coronary arterioles, respectively. Skeletal muscle citrate synthase activity was decreased and left ventricular brain natriuretic peptide levels increased in HF vs. CON and HF-IT animals. A parallel decrease in NS-1619-dependent coronary vasodilatory reserve in vivo and isolated coronary arteriole vasodilatory responsiveness in vitro were observed in HF animals compared with CON, which was prevented in the HF-IT group. Although exercise training prevented BKCa channel-mediated coronary vascular dysfunction, it did not change BKCa channel α-subunit mRNA, protein, or cellular location (i.e., membrane vs. cytoplasm). In conclusion, these results demonstrate the viability of chronic interval exercise training as a therapy for central and peripheral adaptations of experimental heart failure, including BKCa channel-mediated coronary vascular dysfunction. NEW & NOTEWORTHY Conventional treatments have failed to improve the prognosis of heart failure with preserved ejection fraction (HFpEF) patients. Our findings show that chronic interval exercise training can prevent BKCa channel-mediated coronary vascular dysfunction in a translational swine model of chronic pressure overload-induced heart failure with relevance to human HFpEF.


2021 ◽  
Author(s):  
Igor N Zelko ◽  
Sujith Dassanayaka ◽  
Marina V Malovichko ◽  
Caitlin M Howard ◽  
Lauren F Garrett ◽  
...  

Benzene is a ubiquitous environmental pollutant abundant in household products, petrochemicals and cigarette smoke. Benzene is a well-known carcinogen in humans and experimental animals; however, little is known about the cardiovascular toxicity of benzene. Recent population-based studies indicate that benzene exposure is associated with an increased risk for heart failure. Nonetheless, it is unclear whether benzene exposure is sufficient to induce and/or exacerbate heart failure. We examined the effects of benzene (50 ppm, 6 h/day, 5 days/week, 6 weeks) or HEPA-filtered air exposure on transverse aortic constriction (TAC)-induced pressure overload in male C57BL/6J mice. Our data show that benzene exposure had no effect on cardiac function in the Sham group; however, it significantly compromised cardiac function as depicted by a significant decrease in fractional shortening and ejection fraction, as compared with TAC/Air-exposed mice. RNA-seq analysis of the cardiac tissue from the TAC/benzene-exposed mice showed a significant increase in several genes associated with adhesion molecules, cell-cell adhesion, inflammation, and stress response. In particular, neutrophils were implicated in our unbiased analyses. Indeed, immunofluorescence studies showed that TAC/benzene exposure promotes infiltration of CD11b+/S100A8+/myeloperoxidase+-positive neutrophils in the hearts by 3-fold. In vitro, the benzene metabolites, hydroquinone and catechol, induced the expression of P-selectin in cardiac microvascular endothelial cells by 5-fold and increased the adhesion of neutrophils to these endothelial cells by 1.5-2.0-fold. Benzene metabolite-induced adhesion of neutrophils to the endothelial cells was attenuated by anti-P-selectin antibody. Together, these data suggest that benzene exacerbates heart failure by promoting endothelial activation and neutrophil recruitment.


1999 ◽  
Vol 87 (4) ◽  
pp. 1339-1345 ◽  
Author(s):  
Y. Lecarpentier ◽  
C. Coirault ◽  
O. Langeron ◽  
F. X. Blanc ◽  
S. Salmeron ◽  
...  

The load dependence (LD) of relaxation was studied in the diaphragm of rabbits with congestive heart failure (CHF). CHF ( n = 15) was induced by combined chronic volume and pressure overload. Aortic insufficiency was induced by forcing a catheter through the aortic sigmoid valves, followed 3 wk later by abdominal aortic stenosis. Six weeks after the first intervention, animals developed CHF. Sham-operated animals served as controls (C; n = 12). Diaphragm mechanics were studied in vitro on isolated strips, at 22°C, in isotonic and isometric loading conditions. Contractility was lower in the CHF group, as reflected by lower total tension: 1.11 ± 0.10 in CHF vs. 2.38 ± 0.15 N/cm2 in C in twitch ( P < 0.001) and 2.46 ± 0.22 in CHF vs. 4.90 ± 0.25 N ⋅ cm−2 in C in tetanus ( P < 0.001). The index LD was used to quantify the load dependence of relaxation: LD is <1 in load-dependent muscles and tends toward 1 in load-independent muscles. LD was significantly higher in CHF than in C rabbits, in both twitch (0.99 ± 0.01 vs. 0.75 ± 0.03; P < 0.001) and tetanus (0.95 ± 0.02 vs. 0.84 ± 0.02; P < 0.001). In the CHF rabbits’ diaphragm, the fall in total tension was linearly related to the fall in load dependence of relaxation. The decrease in load dependence of relaxation in CHF animals suggests sarcoplasmic reticulum abnormalities. Impairment of the sarcoplasmic reticulum may also partly account for the decrease in contractile performance of diaphragm in CHF animals.


2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Ane Miren Salvador ◽  
Tania Nevers ◽  
Francisco Velazquez ◽  
Mark Aronovitz ◽  
Pilar Alcaide

Background: Left ventricular (LV) dysfunction and Heart Failure (HF) are associated in humans and mice with increased circulating chemokines CXCL9, CXCL10 and CXCL11. Expression of their receptor, CXCR3, in circulating T cells is associated with disease progression in HF patients. We recently published that ICAM1 is significantly upregulated in the LV endothelium and contributes to the progression of HF by regulating T cell recruitment to the LV in a mouse model of pressure overload (PO) induced HF. As CXCR3 can signal to integrins upon chemokine recognition and induce T cell adhesion to endothelial cells under flow conditions in vitro , we hypothesize that chemokine signaling through CXCR3 contributes to LV T cell recruitment and regulates integrin dependent adhesion to ICAM1 in PO induced HF. Methods and results: We used the mouse model of Thoracic Aortic Constriction (TAC) to induce LV remodeling and HF in WT and ICAM1 -/- mice, cardiac fibroblasts (CFB) isolated from adult C57/BL6 mice, flow cytometry and qPCR in mouse tissues and in cells cultured in vitro . The LV expression of CXCL9, 10 and 11 was upregulated in WT mice in response to 2 and 4 weeks TAC as compared to Sham, correlating with ICAM1, IL-6 and IL-1β upregulation and increased CXCR3+ T cell LV infiltration. In vitro , CFB cultured with CXCR3+ T cells or with their culture supernatants, induced CXCL9, 10 and 11, as compared to control media cultured CFB, suggesting CFB are a source of these chemokines under stress. 4 weeks post TAC in WT mice, LV recruited CXCR3+ T cells, as well as mediastinal lymph node and circulating CXCR3+ lymphocytes expressed higher levels of the integrin LFA1, the main ligand of ICAM1, than CXCR3- T cells. The same pattern was observed in systemic CXCR3+ T cells in ICAM1 -/- mice, which, in contrast to WT mice, had reduced LV infiltrated T cells. Conclusion: Our data supports a CXCR3-LFA1-ICAM1 axis being involved in non- ischemic HF. Further studies will determine the CXCR3 ligands triggering T cell LFA1 activation through CXCR3 and whether this mechanism regulates the pathology of non- ischemic HF via ICAM-1 mediated adhesion.


2013 ◽  
Vol 210 (4) ◽  
pp. 665-673 ◽  
Author(s):  
Mikito Takefuji ◽  
Marcus Krüger ◽  
Kishor K. Sivaraj ◽  
Kozo Kaibuchi ◽  
Stefan Offermanns ◽  
...  

Structural cardiac remodeling, including hypertrophy and fibrosis, plays a crucial role in the pathogenesis of heart failure. In vitro studies suggested a role of the small GTPase RhoA in hypertrophic cardiomyocyte growth, but neither the molecular mechanisms leading to RhoA activation nor their relevance in vivo are known. We use here a mass spectrometric approach to identify Rho guanine nucleotide exchange factors (RhoGEFs) activated during cardiac pressure overload in vivo and show that RhoGEF12 is a central player during cardiac remodeling. We show that RhoGEF12 is required for stretch-induced RhoA activation and hypertrophic gene transcription in vitro and that its activation depends on integrin β1 and heterotrimeric G proteins of the G12/13 family. In vivo, cardiomyocyte-specific deletion of RhoGEF12 protects mice from overload-induced hypertrophy, fibrosis, and development of heart failure. Importantly, in mice with preexisting hypertrophy, induction of RhoGEF12 deficiency protects from cardiac decompensation, resulting in significantly increased long-term survival. Collectively, RhoGEF12 acts as an integrator of stretch-induced signaling cascades in cardiomyocytes and is an interesting new target for therapeutic intervention in patients with pressure overload–induced heart failure.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K.M Herum ◽  
G Gilles ◽  
A Romaine ◽  
A.O Melleby ◽  
G Christensen ◽  
...  

Abstract Introduction Activation of cardiac fibroblasts (CFB) is a key step in development of fibrosis in the heart. It was recently shown that, in addition to the well-studied myofibroblast (myoFB) phenotype, activated cardiac fibroblasts can adopt a newly defined matrifibrocyte phenotype, characterized by expression of extracellular matrix (ECM) genes associated with bone, cartilage and tendon development. However, it is unknown whether matrifibrocytes exists in the pressure-overloaded fibrotic and failing heart, and whether substrate stiffness drives differentiation. Hypothesis Matrifibrocyte differentiation occurs in vitro during culturing of primary cardiac fibroblasts, and in vivo in response to left ventricular pressure overload. Methods Left ventricular pressure overload induced by o-ring aortic banding (ORAB) induced cardiac phenotypes of concentric hypertrophic remodelling and congestive heart failure. Primary CFB from adult mice were cultured on plastic or soft polyacrylamide hydrogels (4.5 kPa) for various times. mRNA expression of phenotypic markers were measured by RT-PCR. Presence of smooth muscle α-actin (SMA) fibers was determined by immunocytochemistry. Results ECM genes normally expressed in bone and cartilage (COMP, CILP-2, OPG and SCX) were upregulated in hypertrophic left ventricles of mice with congestive heart failure. The myoFB marker acta2 was increased 2 weeks after ORAB, returned to baseline at 4 weeks and increased again at 20 weeks when the left ventricle was dilating and failing, indicating that the myoFB phenotype is not permanent. In vitro, primary CFB upregulated bone/cartilage-associated ECM genes after 12 days of culturing on plastic. Acta2 mRNA and SMA protein levels peaked after 9 days in culture whereafter they declined, indicating a shift in phenotype. Culturing primary CFB on soft (4.5 kPa) hydrogels delayed, but did not prevent, myoFB differentiation while expression of bone/cartilage ECM genes was absent or low, indicating that high stiffness is a driver of the matrifibrocyte phenotype. Blockers of mechanotransduction, SB431542 (TGFβRI inhibitor), Y27623 (ROCK inhibitor) and cyclosporine A (calcineurin inhibitor), completely inhibited myoFB differentiation but upregulated several matrifibrocyte markers, indicating that distinct signaling pathways regulate myoFB and matrifibrocyte differentiation. Removing inhibitors re-induced myofibroblast markers in cells on plastic but not on soft gels consistent with high stiffness promoting myofibroblast differentiation. Conclusion Primary cardiac fibroblasts acquire characteristics of matrifibrocytes in vitro when cultured for long time on plastic and in vivo in left ventricles of mice with pressure overload-induced congestive heart failure. Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): Marie Sklodowska-Curie Individual Fellowship


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Shi Peng ◽  
Xiao-feng Lu ◽  
Yi-ding Qi ◽  
Jing Li ◽  
Juan Xu ◽  
...  

Aims. We aimed to investigate whether LCZ696 protects against pathological cardiac hypertrophy by regulating the Sirt3/MnSOD pathway. Methods. In vivo, we established a transverse aortic constriction animal model to establish pressure overload-induced heart failure. Subsequently, the mice were given LCZ696 by oral gavage for 4 weeks. After that, the mice underwent transthoracic echocardiography before they were sacrificed. In vitro, we introduced phenylephrine to prime neonatal rat cardiomyocytes and small-interfering RNA to knock down Sirt3 expression. Results. Pathological hypertrophic stimuli caused cardiac hypertrophy and fibrosis and reduced the expression levels of Sirt3 and MnSOD. LCZ696 alleviated the accumulation of oxidative reactive oxygen species (ROS) and cardiomyocyte apoptosis. Furthermore, Sirt3 deficiency abolished the protective effect of LCZ696 on cardiomyocyte hypertrophy, indicating that LCZ696 induced the upregulation of MnSOD and phosphorylation of AMPK through a Sirt3-dependent pathway. Conclusions. LCZ696 may mitigate myocardium oxidative stress and apoptosis in pressure overload-induced heart failure by regulating the Sirt3/MnSOD pathway.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Rajika Roy ◽  
Santhanam Shanmughapriya ◽  
Xueqian Zhang ◽  
Jianliang Song ◽  
Dhanendra Tomar ◽  
...  

Cardiac contractility is regulated by the intracellular Ca 2+ concentration fluxes which are actively regulated by multiple channels and transporters. Ca 2+ uptake into the mitochondrial matrix is precisely controlled by the highly Ca 2+ selective channel, Mitochondrial Calcium Uniporter (MCU). Earlier studies on the cardiac-specific acute MCU knockout and a transgenic dominant-negative MCU mice have demonstrated that mitochondrial Ca 2+ ( m Ca 2+ ) signaling is necessary for cardiac ‘‘fight-or-flight’’ contractile response, however, the role of m Ca 2+ buffering to shape global cytosolic Ca 2+ levels and affect E-C coupling, particularly the Ca 2+ transient, on a beat-to-beat basis still remains to be solved. Our earlier studies have demonstrated that loss of MCU Regulator 1 (MCUR1) in cardiomyocytes results in the impaired m Ca 2+ uptake. We have now employed the cardiac-specific MCUR1 knockout mouse to dissect the precise role of MCU in regulating cytosolic Ca 2+ transients associated with excitation-contraction (E-C) coupling and cardiac function. Results from our studies including the in vivo analyses of cardiac physiology during normal and pressure-overloaded mouse models and in vitro experiments including single-cell cardiac contractility, calcium transients, and electrophysiology measurements demonstrate that MCUR1/MCU regulated m Ca 2+ buffering in cardiomyocytes, although insignificant under basal condition, becomes critical in stress induced conditions and actively participates in regulating the c Ca 2+ transients. Also, the ablation of MCUR1 in cardiomyocytes during stress conditions prevents m Ca 2+ overload and subsequent mROS overproduction. Our data indicate that MCUR1 ablation offers protection against pressure-overload cardiac hypertrophy. In summary, our results provide critical insights into the mechanisms by which the MCU channel contributes in regulating the contractile function of the cardiomyocytes and the role of m Ca 2+ in the development and progression of heart failure.


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