Polychlorinated biphenyls reduce the kinematics contractile properties of embryonic stem cells-derived cardiomyocytes by disrupting their intracellular Ca2+ dynamics

Paola Rebuzzini,Francesco Moccia,Juan Arechaga,Pawan Faris,Lorenzo Fassina,Silvia Garagna,Cinzia Civello,Estella Zuccolo,Maurizio Zuccotti,Amaia Izquierdo

doi:10.1038/s41598-018-36333-z

Abstract

Persistent organic pollutants are a group of chemicals that include polychlorinated biphenyls (PCBs). PCBs exposure during adult life increases incidence and severity of cardiomyopathies, whereas in utero exposure determines congenital heart defects. Being fat-soluble, PCBs are passed to newborns through maternal milk, impairing heart functionality in the adult. It is still unknown how PCBs impair cardiac contraction at cellular/molecular levels. Here, we study the molecular mechanisms by which PCBs cause the observed heart contraction defects, analysing the alterations of Ca2+ toolkit components that regulate contraction. We investigated the effect that Aroclor 1254 (Aroclor), a mixture of PCBs, has on perinatal-like cardiomyocytes derived from mouse embryonic stem cells. Cardiomyocytes, exposed to 1 or 2 µg/ml Aroclor for 24 h, were analyzed for their kinematics contractile properties and intracellular Ca2+ dynamics. We observed that Aroclor impairs cardiomyocytes contractile properties by inhibiting spontaneous Ca2+ oscillations. It disrupts intracellular Ca2+ homeostasis by reducing the sarcoplasmic reticulum Ca2+ content and by inhibiting voltage-gated Ca2+ entry. These findings contribute to the understanding of the molecular underpinnings of PCBs-induced cardiovascular alterations, which are emerging as an additional life-threatening hurdle associated to PCBs pollution. Therefore, PCBs-dependent alteration of intracellular Ca2+ dynamics is the most likely trigger of developmental cardiac functional alteration.

Highlights

Persistent organic pollutants are a variegated group of chemicals that include polychlorinated biphenyls (PCBs), the latter compounds containing a high number of chlorine atoms
Our study aims at dissecting the key physiological processes behind the observed heart contraction defects, by analyzing in perinatal cardiomyocytes the calcium-induced calcium-release mechanism (Ca2+ toolkit) that finely regulates contraction
Our study demonstrates that Aroclor exerts its detrimental effects on the beating properties of perinatal-like cardiomyocytes, acting on the intracellular Ca2+ machinery

Summary

Introduction

Persistent organic pollutants are a variegated group of chemicals that include polychlorinated biphenyls (PCBs), the latter compounds containing a high number of chlorine atoms. PCBs have been widely used in electrical and electronic industries (production of plastics, adhesives, paints, carbonless copying paper, newsprint and caulking compounds1,2), since when, in 1979, their production and use were internationally banned Due to their high chemical stability, PCBs are still persisting and have wide diffusion into the environment. PCBs prenatal exposure through placenta determines congenital heart defects[13,14] not attributable to inherited genetic mutations[5]. To this regard, exposed avian embryos display extensive cardiac dilation, thinner ventricle walls and reduced responsiveness to chronotropic stimuli[15], whereas zebrafish embryos show heart defects, reduction of the heart beating rate and irregular and weak contractions[16]. Our study aims at dissecting the key physiological processes behind the observed heart contraction defects, by analyzing in perinatal cardiomyocytes the calcium-induced calcium-release mechanism (Ca2+ toolkit) that finely regulates contraction

Methods

Results

Conclusion