hiPSC-based model of prenatal exposure to cannabinoids: effect on neuronal differentiation

Copyright © 2020 Miranda, Barata, Vaz, Ferreira, Quintas and Bekman. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Phytocannabinoids are psychotropic substances ofcannabis with the ability to bind endocannabinoid (eCB) receptors that regulate synaptic activity in the central nervous system (CNS). Synthetic cannabinoids (SCs) are synthetic analogs of Δ9-tetrahydrocannabinol (Δ9-THC), the psychotropic compound of cannabis, acting as agonists of eCB receptor CB1. SC is an easily available and popular alternative to cannabis, and their molecular structure is always changing, increasing the hazard for the general population. The popularity of cannabis and its derivatives may lead, and often does, to a child's exposure to cannabis both in utero and through breastfeeding by a drug-consuming mother. Prenatal exposure to cannabis has been associated with an altered rate of mental development and significant changes in nervous system functioning. However, the understanding of mechanisms of its action on developing the human CNS is still lacking. We investigated the effect of continuous exposure to cannabinoids on developing human neurons, mimicking the prenatal exposure by drug-consuming mother. Two human induced pluripotent stem cells (hiPSC) lines were induced to differentiate into neuronal cells and exposed for 37 days to cannabidiol (CBD), Δ9-THC, and two SCs, THJ-018 and EG-018. Both Δ9-THC and SC, at 10 μM, promote precocious neuronal and glial differentiation, while CBD at the same concentration is neurotoxic. Neurons exposed to Δ9-THC and SC show abnormal functioning of voltage-gated calcium channels when stimulated by extracellular potassium. In sum, all studied substances have a profound impact on the developing neurons, highlighting the importance of thorough research on the impact of prenatal exposure to natural and SC.This work was supported by the Fundação para a Ciência e a Tecnologia (FCT), Portugal (SFRH/BPD/81627/2011 to SV), by iBB — Institute for Bioengineering and Biosciences — project UIDB/04565/2020, and by Egas Moniz Higher Institute of Health Science (Egas Moniz, CRL). Funding was also received from the European Union’s Horizon 2020 Research and Innovation programme, under the Grant Agreement number 739572—The Discoveries Centre for Regenerative and Precision Medicine H2020-WIDESPREAD-01-2016-2017 to EB.info:eu-repo/semantics/publishedVersio

Basic opto-electronics on silicon for sensor applications

A general platform for integrated opto-electronic sensor systems on silicon is proposed. The system is based on a hybridly integrated semiconductor laser, ZnO optical waveguides and monolithic photodiodes and electronic circuiry

Scalable generation of cerebellar neurons from pluripotent stem cells

Human induced pluripotent stem cells (iPSCs) have great potential for disease modeling and provide a valuable source for regenerative approaches. However, generating iPSC-derived models to study brain diseases remains a challenge. In particular, our ability to differentiate cerebellar neurons from pluripotent stem cells is still limited. Recently, we described the long-term culture of cerebellar neuroepithelium formed from human iPSCs, recapitulating the early developmental events of the cerebellum. Additionally, an efficient maturation of replated cerebellar progenitors into distinct types of functional cerebellar neurons was also achieved under defined and feeder-free conditions. However, developing a scalable protocol that allows to produce large numbers of organoids and high yields of mature neurons in a 3D bioreactor culture systems is still a difficult challenge. In this work, we present a new approach for the reproducible and scalable generation of mid-hindbrain organoids under chemically defined conditions by using the novel PBS 0.1 (100 mL) Vertical-Wheel single-use bioreactor. In this system, an efficient cell aggregation with shape and size-controlled aggregates can be obtained, which is important for homogeneous and efficient differentiation. Moreover, a larger amount of iPSC-derived aggregates can be generated without being excessively labour-intensive, achieving 431 ± 53.6 aggregates/mL at 24 hours after seeding. After differentiation, distinct types of cerebellar neurons were generated, including Purkinje cells (Calbindin+), Granule cells (BARHL1+ and Pax6+), Golgi cells (Neurogranin+ and GAD65+), Deep cerebellar nuclei projection neurons (TBR1+) and Non-Golgi-type interneurons (Parvalbumin+ and Calbindin-). These cells show signs of efficient maturation, staining positive for MAP2, and are able to change intracellular Ca2+ concentration following KCl stimulation. In this system, human iPSC-derived organoids are able to mature into different mature cerebellar neurons and to survive for up to 3 months, without replating and co-culture with feeder layers

Matter effects and CP violating neutrino oscillations with non-decoupling heavy neutrinos

The evolution equation for active and sterile neutrinos propagating in general anisotropic or polarized background environment is found and solved for a special case when heavy neutrinos do not decouple, resulting in non-unitary mixing among light neutrino states. Then new CP violating neutrino oscillation effects appear. In contrast to the standard unitary neutrino oscillations these effects can be visible even for two flavour neutrino transitions and even if one of the elements of the neutrino mixing matrix is equal to zero. They do not necessarily vanish with $\delta m^{2} \to 0$ and they are different for various pairs of flavour neutrino transitions ($\nu_e \to \nu_\mu$), ($\nu_\mu \to \nu_\tau$), ($\nu_\tau \to \nu_e$). Neutrino oscillations in vacuum and Earth's matter are calculated for some fixed baseline experiments and a comparison between unitary and non-unitary oscillations are presented. It is shown, taking into account the present experimental constraints, that heavy neutrino states can affect CP and T asymmetries. This is especially true in the case of $\nu_\mu \to \nu_\tau$ oscillations.Comment: 18 pages, 6 fig

Modeling Rett syndrome with human patient-specific forebrain organoids

Copyright © 2020 Gomes, Fernandes, Vaz, Silva, Bekman, Xapelli, Duarte, Ghazvini, Gribnau, Muotri, Trujillo, Sebastião, Cabral and Diogo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Engineering brain organoids from human induced pluripotent stem cells (hiPSCs) is a powerful tool for modeling brain development and neurological disorders. Rett syndrome (RTT), a rare neurodevelopmental disorder, can greatly benefit from this technology, since it affects multiple neuronal subtypes in forebrain sub-regions. We have established dorsal and ventral forebrain organoids from control and RTT patient-specific hiPSCs recapitulating 3D organization and functional network complexity. Our data revealed a premature development of the deep-cortical layer, associated to the formation of TBR1 and CTIP2 neurons, and a lower expression of neural progenitor/proliferative cells in female RTT dorsal organoids. Moreover, calcium imaging and electrophysiology analysis demonstrated functional defects of RTT neurons. Additionally, assembly of RTT dorsal and ventral organoids revealed impairments of interneuron's migration. Overall, our models provide a better understanding of RTT during early stages of neural development, demonstrating a great potential for personalized diagnosis and drug screening.We also acknowledge financial support from Fundação para a Ciência e a Tecnologia (FCT), Portugal, through iBB, Institute for Bioengineering and Biosciences (UIDB/04565/2020) and from Programa Operacional Regional de Lisboa 2020 (Project No. 007317). AG was supported by FCT (PD/BD/128373/2017).info:eu-repo/semantics/publishedVersio

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The presence of right-handed neutrinos in the type I seesaw mechanism may lead to significant corrections to the RG evolution of the Higgs self-coupling. Compared to the Standard Model case, the Higgs mass window can become narrower, and the cutoff scale become lower. Naively, these effects decrease with decreasing right-handed neutrino mass. However, we point out that the unknown Dirac Yukawa matrix may impact the vacuum stability constraints even in the low scale seesaw case not far away from the electroweak scale, hence much below the canonical seesaw scale of 10^15 GeV. This includes situations in which production of right-handed neutrinos at colliders is possible. We illustrate this within a particular parametrization of the Dirac Yukawas and with explicit low scale seesaw models. We also note the effect of massive neutrinos on the top quark Yukawa coupling, whose high energy value can be increased with respect to the Standard Model case.Comment: 17 pages, 7 figures, minor revisions, version to appear in JHE

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We investigate non-standard Hamiltonian effects on neutrino oscillations, which are effective additional contributions to the vacuum or matter Hamiltonian. Since these effects can enter in either flavor or mass basis, we develop an understanding of the difference between these bases representing the underlying theoretical model. In particular, the simplest of these effects are classified as ``pure'' flavor or mass effects, where the appearance of such a ``pure'' effect can be quite plausible as a leading non-standard contribution from theoretical models. Compared to earlier studies investigating particular effects, we aim for a top-down classification of a possible ``new physics'' signature at future long-baseline neutrino oscillation precision experiments. We develop a general framework for such effects with two neutrino flavors and discuss the extension to three neutrino flavors, as well as we demonstrate the challenges for a neutrino factory to distinguish the theoretical origin of these effects with a numerical example. We find how the precision measurement of neutrino oscillation parameters can be altered by non-standard effects alone (not including non-standard interactions in the creation and detection processes) and that the non-standard effects on Hamiltonian level can be distinguished from other non-standard effects (such as neutrino decoherence and decay) if we consider specific imprint of the effects on the energy spectra of several different oscillation channels at a neutrino factory.Comment: 30 pages, 6 figures, LaTeX, final version, published in Eur.Phys.J.