Project description:To investiage the ability of positve inotropism from myocardial Rad reduction we induced Rad knockout after onset of pressure overload to reverse or compensate progression of heart failure
Project description:Despite some success of pharmacotherapies targeting primarily neurohormonal dysregulation, heart failure is a growing global pandemic with increasing burden. Treatments that improve the disease by reversing heart failure at the cardiomyocyte level are lacking. MicroRNAs (miRNA) are transcriptional regulators of gene expression, acting through complex biological networks, and playing thereby essential roles in disease progression. Adverse structural remodelling of the left ventricle due to myocardial infarction (MI) is a common pathological feature leading to heart failure. We previously demonstrated increased cardiomyocyte expression of the miR-212/132 family during pathological cardiac conditions. Transgenic mice overexpressing the miR-212/132 cluster (miR-212/132-TG) develop pathological cardiac remodelling and die prematurely from progressive HF. Using both knockout and antisense strategies, we have shown miR-132 to be both necessary and sufficient to drive the pathological growth of cardiomyocytes in a murine model of left ventricular pressure overload. Based on the findings, we proposed that miR-132 may serve as a therapeutic target in heart failure therapy. Here we provide novel mechanistic insight and translational evidence for the therapeutic efficacy in small and large animal models (n=135) of heart failure. We demonstrate strong PK/PD relationship, dose-dependent efficacy and high clinical potential of a novel optimized synthetic locked nucleic acid phosphorothioate backbone antisense oligonucleotide inhibitor of miR-132 (antimiR-132) as a next-generation heart failure therapeutic.
Project description:Mice without cardiac Bmal1 function develop severe progressive heart failure with age. To examine the mechanism underlying the failing heart phenotype observed in heart-specific Bmal1 knockout mice, microarray analyses were performed. The analyses revealed that broad classes of genes regulating cellular energy metabolism were upregulated or downregulated in the heart tissues of heart-specific Bmal1 knockout mice compared with those of control animals. Heart total RNA extracted from six animals per genotype (control and heart-specific Bmal1 knockout) was pooled and then used for a microarray analysis.
Project description:We tested it in an animal model of myocardial infarction to ensure whether early initiation of dapagliflozin (DAPA), or different orders of combination with sacubitril-valsartan would result in a greater improvement of heart function than sacubitril-valsartan alone in post-myocardial infarction heart failure.
Project description:Heart failure remains one of the largest clinical burdens globally, with little to no improvement in the development of disease-eradicating therapeutics. Integrin targeting has been used in the treatment of ocular disease and cancer, but little is known about its utility in the treatment of heart failure. Here we sought to determine whether the second generation orally available, αvβ3-specific RGD-mimetic, 29P, was cardioprotective. Male mice were subjected to transverse aortic constriction (TAC) and treated with 50μg/kg 29P or volume-matched saline as Vehicle control. At 3 weeks post-TAC, echocardiography showed that 29P treatment significantly restored cardiac function and structure indicating the protective effect of 29P treatment in this model of heart failure. Importantly, 29P treatment improved cardiac function giving improved fractional shortening, ejection fraction, heart weight and lung weight to tibia length fractions, together with partial restoration of Ace and Mme levels, as markers of the TAC insult. At a tissue level, 29P reduced cardiomyocyte hypertrophy and interstitial fibrosis, both of which are major clinical features of heart failure. RNA sequencing identified that, mechanistically, this occurred with concomitant alterations to genes involved molecular pathways associated with these processes such as metabolism, hypertrophy and basement membrane formation. Overall, targeting αvβ3 with 29P provides a novel strategy to attenuate pressure-overload induced cardiac hypertrophy and fibrosis, providing a possible new approach to heart failure treatment.
Project description:One of the most recognizable physiological phenomena is the adrenergic-induced fight-or-flight increase in heart rate and cardiac contraction. For the β-adenergic agonist-induced enhancement of calcium influx and transients, and contractility in the heart, we identify the dual requirement of a subpopulation of Rad-bound calcium channels under basal conditions and PKA phosphorylation of Rad. In mice expressing a non-phosphorylatable Rad mutant, basal cardiac contractility is reduced and adrenergic-augmentation of the calcium current and contractility are disabled. Expression of mutant calcium channel β-subunits that cannot bind the mutant Rad restored contractility, revealing a highly specific therapeutic approach to mimic the contractility imparted by adrenergic agonists. Our findings place Rad and its modulation of calcium channels at the nexus of adrenergic modulation of cardiac responses.
Project description:Mice without cardiac Bmal1 function develop severe progressive heart failure with age. To examine the mechanism underlying the failing heart phenotype observed in heart-specific Bmal1 knockout mice, microarray analyses were performed. The analyses revealed that broad classes of genes regulating cellular energy metabolism were upregulated or downregulated in the heart tissues of heart-specific Bmal1 knockout mice compared with those of control animals.