Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples

Cardiomyocytes from diseased hearts are subjected to complex remodeling processes involving changes in cell structure, excitation contraction coupling and ...

University of Florence

The strawberry (Fragaria X ananassa, Duch.) represents a relevant source of micronutrients, such as minerals, vitamin C, folate and phenolic substances, most of which are natural antioxidants and contribute to the high nutritional quality of the fruit. All these compounds are essential for health and, in particular, strawberry phenolics are best known for their antioxidant and anti-inflammatory action, and possess directly and indirectly antimicrobial, anti-allergy and anti-hypertensive properties, as well as the capacity to inhibit the activities of some physiological enzymes and receptor properties. The main objective of this article is to review and update the current knowledge on the potential impact of the strawberry on human health, with particular attention on compounds and their possible mechanisms of action.

The potential impact of strawberry on human health.

In the developing and mature central nervous system, NG2 expressing cells comprise a population of cycling oligodendrocyte progenitor cells (OPCs) that differentiate into mature, myelinating oligodendrocytes (OLGs). OPCs are also characterized by high motility and respond to injury by migrating into the lesioned area to support remyelination. K(+) currents in OPCs are developmentally regulated during differentiation. However, the mechanisms regulating these currents at different stages of oligodendrocyte lineage are poorly understood. Here we show that, in cultured primary OPCs, the purinergic G-protein coupled receptor GPR17, that has recently emerged as a key player in oligodendrogliogenesis, crucially regulates K(+) currents. Specifically, receptor stimulation by its agonist UDP-glucose enhances delayed rectifier K(+) currents without affecting transient K(+) conductances. This effect was observed in a subpopulation of OPCs and immature pre-OLGs whereas it was absent in mature OLGs, in line with GPR17 expression, that peaks at intermediate phases of oligodendrocyte differentiation and is thereafter downregulated to allow terminal maturation. The effect of UDP-glucose on K(+) currents is concentration-dependent, blocked by the GPR17 antagonists MRS2179 and cangrelor, and sensitive to the K(+) channel blocker tetraethyl-ammonium, which also inhibits oligodendrocyte maturation. We propose that stimulation of K(+) currents is responsible for GPR17-induced oligodendrocyte differentiation. Moreover, we demonstrate, for the first time, that GPR17 activation stimulates OPC migration, suggesting an important role for this receptor after brain injury. Our data indicate that modulation of GPR17 may represent a strategy to potentiate the post-traumatic response of OPCs under demyelinating conditions, such as multiple sclerosis, stroke, and brain trauma.

UDP-glucose enhances outward K(+) currents necessary for cell differentiation and stimulates cell migration by activating the GPR17 receptor in oligodendrocyte precursors.

Mitochondria are essential organelles for cellular integrity and functionality maintenance and their imparement is implicated in the development of a wide range of diseases, including metabolic, cardiovascular, degenerative and hyperproliferative pathologies. The identification of different compounds able to interact with mitochondria for therapeutic purposes is currently becoming of primary importance. Indeed, it is well known that foods, particularly those of vegetable origin, present several constituents with beneficial effects on health. This review summarizes and updates the most recent findings concerning the mechanisms through which different dietary compounds from plant foods affect mitochondria functionality in healthy and pathological in vitro and in vivo models, paying particular attention to the pathways involved in mitochondrial biogenesis and apoptosis.

The effects of bioactive compounds from plant foods on mitochondrial function: A focus on apoptotic mechanisms.

Transmembrane sodium (Na(+)) fluxes and intracellular sodium homeostasis are central players in the physiology of the cardiac myocyte, since they are crucial for both cell excitability and for the regulation of the intracellular calcium concentration. Furthermore, Na(+) fluxes across the membrane of mitochondria affect the concentration of protons and calcium in the matrix, regulating mitochondrial function. In this review we first analyze the main molecular determinants of sodium fluxes across the sarcolemma and the mitochondrial membrane and describe their role in the physiology of the healthy myocyte. In particular we focus on the interplay between intracellular Ca(2+) and Na(+). A large part of the review is dedicated to discuss the changes of Na(+) fluxes and intracellular Na(+) concentration([Na(+)]i) occurring in cardiac disease; we specifically focus on heart failure and hypertrophic cardiomyopathy, where increased intracellular [Na(+)]i is an established determinant of myocardial dysfunction. We review experimental evidence attributing the increase of [Na(+)]i to either decreased Na(+) efflux (e.g. via the Na(+)/K(+) pump) or increased Na(+) influx into the myocyte (e.g. via Na(+) channels). In particular, we focus on the role of the "late sodium current" (INaL), a sustained component of the fast Na(+) current of cardiac myocytes, which is abnormally enhanced in cardiac diseases and contributes to both electrical and contractile dysfunction. We analyze the pathophysiological role of INaL enhancement in heart failure and hypertrophic cardiomyopathy and the consequences of its pharmacological modulation, highlighting the clinical implications. The central role of Na(+) fluxes and intracellular Na(+) physiology and pathophysiology of cardiac myocytes has been highlighted by a large number of recent works. The possibility of modulating Na(+) inward fluxes and [Na(+)]i with specific INaL inhibitors, such as ranolazine, has made Na(+)a novel suitable target for cardiac therapy, potentially capable of addressing arrhythmogenesis and diastolic dysfunction in severe conditions such as heart failure and hypertrophic cardiomyopathy.

Regulation of intracellular Na(+) in health and disease: pathophysiological mechanisms and implications for treatment.

This study evaluated 20 advanced selections, derived from a strawberry inter-specific back-cross program, and their parents, for fruit weight, commercial yield, acidity, sugar content, antioxidant capacity, phenol and anthocyanin content. Phytochemical profiling analysis was performed to determine the compositional characteristics of the improved selections in comparison with their parents and an important commercial variety (Elsanta). Advanced selections showed substantial improvement for agronomic and nutritional quality parameters. From the profiling analysis there was evidence for specific improvements in fruit phytochemical contents; new advanced selections had a substantially increased fruit flavonol, anthocyanin and ellagitannin contents compared to their parent cv. Romina and, for flavonols and ellagitannins, compared to a standard cultivar Elsanta. Such results confirm that an appropriate breeding program that includes wild strawberry germplasm can produce new strawberry cultivars with a well-defined improvement in fruit nutritional and nutraceutical value.

Luca Mazzoni

Department NeuroFarBa,
Division of Pharmacology,
Department NeuroFarBa, Division of Pharmacology

University of Florence

Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples

Luca Mazzoni

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University of Florence

Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples

Department NeuroFarBa,
Division of Pharmacology,
Department NeuroFarBa, Division of Pharmacology