A comparison of adenovirally delivered molecular methods to inhibit Na+/Ca2+ exchange

The Influence of Diet on MicroRNAs that Impact Cardiovascular Disease

Food quality and nutritional habits strongly influence human health status. Extensive research has been conducted to confirm that foods rich in biologically active nutrients have a positive impact on the onset and development of different pathological processes, including cardiovascular diseases. However, the underlying mechanisms by which dietary compounds regulate cardiovascular function have not yet been fully clarified. A growing number of studies confirm that bioactive food components modulate various signaling pathways which are involved in heart physiology and pathology. Recent evidence indicates that microRNAs (miRNAs), small single-stranded RNA chains with a powerful ability to influence protein expression in the whole organism, have a significant role in the regulation of cardiovascular-related pathways. This review summarizes recent studies dealing with the impact of some biologically active nutrients like polyunsaturated fatty acids (PUFAs), vitamins E and D, dietary fiber, or selenium on the expression of many miRNAs, which are connected with cardiovascular diseases. Current research indicates that the expression levels of many cardiovascular-related miRNAs like miRNA-21, -30 family, -34, -155, or -199 can be altered by foods and dietary supplements in various animal and human disease models. Understanding the dietary modulation of miRNAs represents, therefore, an important field for further research. The acquired knowledge may be used in personalized nutritional prevention of cardiovascular disease or the treatment of cardiovascular disorders.

Triple threat: the Na+/Ca2+ exchanger in the pathophysiology of cardiac arrhythmia, ischemia and heart failure

The Na(+)/Ca(2+) exchanger (NCX) is the main Ca(2+) extrusion mechanism of the cardiac myocyte and thus is crucial for maintaining Ca(2+) homeostasis. It is involved in the regulation of several parameters of cardiac excitation contraction coupling, such as cytosolic Ca(2+) concentration, repolarization and contractility. Increased NCX activity has been identified as a mechanism promoting heart failure, cardiac ischemia and arrhythmia. Transgenic mice as well as pharmacological interventions have been used to support the idea of using NCX inhibition as a future pharmacological strategy to treat cardiovascular disease.

Reduced expression of the Na+/Ca2+ exchanger in adult cardiomyocytes via adenovirally delivered shRNA results in resistance to simulated ischemic injury

The Na+/Ca2+ exchanger (NCX) is proposed to be an important protein in the regulation of Ca2+ movements in the heart. This Ca2+ regulatory action is thought to modulate contractile activity in the heart under normal physiological conditions and may contribute to the Ca2+ overload that occurs during ischemic reperfusion challenge. To evaluate these hypotheses, adult rat cardiomyocytes were exposed to an adenovirus that codes for short hairpin RNA (shRNA) targeting NCX gene expression through RNA interference. An adenovirus transcribing a short RNA with a scrambled nucleotide sequence was compared with the NCX-shRNA nucleotide sequence and used as a control. Freshly isolated rat cardiomyocytes were infected with virus for 48 h before examination. Cardiomyocytes maintained their characteristic morphological appearance during this short time period after isolation. NCX expression was inhibited by up to ∼60% by the shRNA treatment as determined by Western blot analysis. The depletion in NCX protein was accompanied by a significant depression of NCX activity in shRNA-treated cells. Ca2+ homeostasis was unaltered in the shRNA-treated cells upon electrical stimulation compared with control cells. However, when cardiomyocytes were exposed to a simulated ischemic solution, NCX-depleted cells were significantly protected from the rise in cytoplasmic Ca2+ and damage that was detected in control cells during ischemia and reperfusion. Our data support the role for NCX in ischemic injury to the heart and demonstrate the usefulness of altering gene expression with an adenoviral-delivery system of shRNA in adult cardiomyocytes.