Rappaport Faculty of Medicine

About: Rappaport Faculty of Medicine is a based out in . It is known for research contribution in the topics: Population & Heparanase. The organization has 3205 authors who have published 3915 publications receiving 114533 citations.

Abnormal neuronal differentiation and mitochondrial dysfunction in hair follicle-derived induced pluripotent stem cells of schizophrenia patients

Abstract: One of the prevailing hypotheses suggests schizophrenia as a neurodevelopmental disorder, involving dysfunction of dopaminergic and glutamatergic systems. Accumulating evidence suggests mitochondria as an additional pathological factor in schizophrenia. An attractive model to study processes related to neurodevelopment in schizophrenia is reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) and differentiating them into different neuronal lineages. iPSCs from three schizophrenia patients and from two controls were reprogrammed from hair follicle keratinocytes, because of their accessibility and common ectodermal origin with neurons. iPSCs were differentiated into Pax6+/Nestin+ neural precursors and then further differentiated into β3-Tubulin+/tyrosine hydroxylase+/DAT+ dopaminergic neurons. In addition, iPSCs were differentiated through embryonic bodies into β3-Tubulin+/Tbox brain1+ glutamatergic neurons. Schizophrenia-derived dopaminergic cells showed severely impaired ability to differentiate, whereas glutamatergic cells were unable to maturate. Mitochondrial respiration and its sensitivity to dopamine-induced inhibition were impaired in schizophrenia-derived keratinocytes and iPSCs. Moreover, we observed dissipation of mitochondrial membrane potential (Δψm) and perturbations in mitochondrial network structure and connectivity in dopaminergic along the differentiation process and in glutamatergic cells. Our data unravel perturbations in neural differentiation and mitochondrial function, which may be interconnected, and of relevance to dysfunctional neurodevelopmental processes in schizophrenia.

Mitochondrial dysfunction in schizophrenia: a possible linkage to dopamine.

Abstract: Mitochondria are not only the principal source of high energy intermediates, but play an important role in intracellular calcium buffering, are main producers of reactive oxygen species, and are the source of pro- and antiapoptotic key factors. Moreover, the mitochondria are of a ubiquitous nature and the respiratory chain has a dual genetic basis, i.e. the mitochondrial and the nuclear DNAs. Thus mitochondrial impairment could provide an explanation for the tremendous heterogeneity of clinical and pathological manifestations in schizophrenia. This article reviews several independent lines of evidence that suggest an involvement of mitochondrial dysfunction in schizophrenia. Among them are altered cerebral energy metabolism, mitochondrial hypoplasia, dysfunction of the oxidative phosphorylation system and altered mitochondrial related gene expression. In addition, the interaction between dopamine, a predominant etiological factor in schizophrenia, and mitochondrial respiration is considered as a possible mechanism underlying the hyper- and hypo-activity cycling in schizophrenia. Understanding the role of mitochondria in schizophrenia may encourage novel treatment approaches, the identification of candidate genes and new insights into the pathophysiology and etiology of the disorder.

Functional properties of human embryonic stem cell-derived cardiomyocytes: intracellular Ca2+ handling and the role of sarcoplasmic reticulum in the contraction.

Abstract: Since cardiac transplantation is limited by the small availability of donor organs, regeneration of the diseased myocardium by cell transplantation is an attractive therapeutic modality. To determine the compatibility of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) (7 to 55 days old) with the myocardium, we investigated their functional properties regarding intracellular Ca2+ handling and the role of the sarcoplasmic reticulum in the contraction. The functional properties of hESC-CMs were investigated by recording simultaneously [Ca2+]i transients and contractions. Additionally, we performed Western blot analysis of the Ca2+-handling proteins SERCA2, calsequestrin, phospholamban, and Na+/Ca2+ exchanger (NCX). Our major findings are, first, that hESC-CMs displayed temporally related [Ca2+]i transients and contractions, negative force-frequency relations, and lack of post-rest potentiation. Second, ryanodine, thapsigargin, and caffeine did not affect the [Ca2+]i transient and contraction, indicating that at this developmental stage, contraction depends on transsarcolemmal Ca2+ influx rather than on sarcoplasmic reticulum Ca2+ release. Third, in agreement with the notion that a voltage-dependent Ca2+ current is present in hESC-CMs and contributes to the mechanical function, verapamil completely blocked contraction. Fourth, whereas hESC-CMs expressed SERCA2 and NCX at levels comparable to those of the adult porcine myocardium, calsequestrin and phospholamban were not expressed. Our study shows for the first time that functional properties related to intracellular Ca2+ handling of hESC-CMs differ markedly from the adult myocardium, probably due to immature sarcoplasmic reticulum capacity.

In vitro antimicrobial activity of olive leaves.

Abstract: We investigated the antimicrobial effect of olive leaves against bacteria and fungi. The microorganisms tested were inoculated in various concentrations of olive leaf water extract. Olive leaf 0.6% (w/v) water extract killed almost all bacteria tested, within 3 h. Dermatophytes were inhibited by 1.25% (w/v) plant extract following a 3-day exposure whereas Candida albicans was killed following a 24 h incubation in the presence of 15% (w/v) plant extract. Olive leaf extract fractions, obtained by dialysis, that showed antimicrobial activity consisted of particles smaller than 1000 molecular rate cutoffs. Scanning electron microscopic observations of C. albicans, exposed to 40% (w/v) olive leaf extract, showed invaginated and amorphous cells. Escherichia coli cells, subjected to a similar treatment but exposed to only 0.6% (w/v) olive leaf extract showed complete destruction. These findings suggest an antimicrobial potential for olive leaves.