Tankyrase Inhibition Attenuates Cardiac Dilatation and Dysfunction in Ischemic Heart Failure

The effects of therapeutic hypothermia on the expression of DKK3 and myocardial ischemia-reperfusion injury

BACKGROUND

The impact and mechanisms of therapeutic hypothermia (TH) on myocardial ischemia-reperfusion (I/R) injury are still unknown.

METHODS

Sprague-Dawley (SD) rat model and primary cardiomyocytes were applied in our study. TTC staining evaluated myocardial infarction, while H&E staining assessed myocardial injury. ELISA quantified lactate dehydrogenase (LDH), IL-1β, IL-6, and TNF-α. Blood serum concentrations of CK, CK-MB, and cTnT were detected using a biochemical assay. TUNEL assay, flow cytometry and western blot were used to detect cell apoptosis. EdU assay was applied to examine cell proliferation. The expression of DKK3 and β-catenin protein was analyzed using Realtime PCR and Western blot.

RESULTS

TH alleviated myocardial infarction size and injury in rat models of I/R, and reduced serum levels of myocardial injury markers and inflammatory factors in animal and cell models. In addition, TH inhibited the increased apoptosis and β-catenin expression as well as decreased DKK3 expression caused by I/R in I/R cell models, while si-DKK3 reversed the changes brought by TH, and XAV939 inhibited the effects of si-DKK3.

CONCLUSION

TH may reduce myocardial infarction size, myocardial injury, inflammatory response and apoptosis through DKK3/Wnt/β-catenin pathway, thereby alleviating myocardial I/R injury.

Deficiency of heme oxygenase 1a causes detrimental effects on cardiac function

Humans lacking heme oxygenase 1 (HMOX1) display growth retardation, haemolytic anaemia, and vulnerability to stress; however, cardiac function remains unclear. We aimed to explore the cardiac function of zebrafish lacking hmox1a at baseline and in response to stress. We generated zebrafish hmox1a mutants using CRISPR/Cas9 genome editing technology. Deletion of hmox1a increases cardiac output and further induces hypertrophy in adults. Adults lacking hmox1a develop myocardial interstitial fibrosis, restrain cardiomyocyte proliferation and downregulate renal haemoglobin and cardiac antioxidative genes. Larvae lacking hmox1a fail to respond to hypoxia, whereas adults are insensitive to isoproterenol stimulation in the heart, suggesting that hmox1a is necessary for cardiac response to stress. Haplodeficiency of hmox1a stimulates non-mitochondrial respiration and cardiac cell proliferation, increases cardiac output in larvae in response to hypoxia, and deteriorates cardiac function and structure in adults upon isoproterenol treatment. Intriguingly, haplodeficiency of hmox1a upregulates cardiac hmox1a and hmox1b in response to isoproterenol. Collectively, deletion of hmox1a results in cardiac remodelling and abrogates cardiac response to hypoxia and isoproterenol. Haplodeficiency of hmox1a aggravates cardiac response to the stress, which could be associated with the upregulation of hmox1a and hmox1b. Our data suggests that HMOX1 homeostasis is essential for maintaining cardiac function and promoting cardioprotective effects.

Wnt Signaling in Atherosclerosis: Mechanisms to Therapeutic Implications

Atherosclerosis is a vascular disease in which inflammation plays a pivotal role. Receptor-mediated signaling pathways regulate vascular inflammation and the pathophysiology of atherosclerosis. Emerging evidence has revealed the role of the Wnt pathway in atherosclerosis progression. The Wnt pathway influences almost all stages of atherosclerosis progression, including endothelial dysfunction, monocyte infiltration, smooth muscle cell proliferation and migration, and plaque formation. Targeting the Wnt pathway to treat atherosclerosis represents a promising therapeutic approach that remains understudied. Blocking Wnt signaling utilizing small molecule inhibitors, recombinant proteins, and/or neutralizing antibodies ameliorates atherosclerosis in preclinical models. The Wnt pathway can be potentially manipulated through targeting Wnt ligands, receptors, co-receptors, and downstream signaling molecules. However, there are challenges associated with developing a real world therapeutic compound that targets the Wnt pathway. This review focuses on the role of Wnt signaling in atherosclerosis development, and the rationale for targeting this pathway for the treatment of atherosclerosis.