Generation of an expandable intermediate mesoderm restricted progenitor cell line from human pluripotent stem cells.

The field of tissue engineering entered a new era with the development of human pluripotent stem cells (hPSCs), which are capable of unlimited expansion whilst retaining the potential to differentiate into all mature cell populations. However, these cells harbor significant risks, including tumor formation upon transplantation. One way to mitigate this risk is to develop expandable progenitor cell populations with restricted differentiation potential. Here, we used a cellular microarray technology to identify a defined and optimized culture condition that supports the derivation and propagation of a cell population with mesodermal properties. This cell population, referred to as intermediate mesodermal progenitor (IMP) cells, is capable of unlimited expansion, lacks tumor formation potential, and, upon appropriate stimulation, readily acquires properties of a sub-population of kidney cells. Interestingly, IMP cells fail to differentiate into other mesodermally-derived tissues, including blood and heart, suggesting that these cells are restricted to an intermediate mesodermal fate

New insights into purinergic receptor signaling in neuronal differentiation, neuroprotection, and brain disorders

Ionotropic P2X and metabotropic P2Y purinergic receptors are expressed in the central nervous system and participate in the synaptic process particularly associated with acetylcholine, GABA, and glutamate neurotransmission. As a result of activation, the P2 receptors promote the elevation of free intracellular calcium concentration as the main signaling pathway. Purinergic signaling is present in early stages of embryogenesis and is involved in processes of cell proliferation, migration, and differentiation. The use of new techniques such as knockout animals, in vitro models of neuronal differentiation, antisense oligonucleotides to induce downregulation of purinergic receptor gene expression, and the development of selective inhibitors for purinergic receptor subtypes contribute to the comprehension of the role of purinergic signaling during neurogenesis. In this review, we shall discuss the participation of purinergic receptors in developmental processes and in brain physiology, including neuron-glia interactions and pathophysiology

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

Brain Organoids and the Study of Neurodevelopment

Brain organoids are 3D self-assembled structures composed of hundreds of thousands to millions of cells that resemble the cellular organization and transcriptional and epigenetic signature of a developing human brain. Advancements using brain organoids have been made to elucidate the genetic basis of certain neurodevelopmental disorders, such as microcephaly and autism; and to investigate the impact of environmental factors to the brain, such as during Zika virus infection. It remains to be explored how far brain organoids can functionally mature and process external information. An improved brain organoid model might reproduce important aspects of the human brain in a more reproducible and high-throughput fashion. This novel and complementary approach in the neuroscience toolbox opens perspectives to understand the fundamental features of the human neurodevelopment, with implications to personalize therapeutic opportunities for neurological disorders

Direct Generation of Human Cortical Organoids from Primary Cells

The study of variations in human neurodevelopment and cognition is limited by the availability of experimental models. While animal models only partially recapitulate the human brain development, genetics, and heterogeneity, human-induced pluripotent stem cells can provide an attractive experimental alternative. However, cellular reprogramming and further differentiation techniques are costly and time-consuming and therefore, studies using this approach are often limited to a small number of samples. In this study, we describe a rapid and cost-effective method to reprogram somatic cells and the direct generation of cortical organoids in a 96-well format. Our data are a proof-of-principle that a large cohort of samples can be generated for experimental assessment of the human neural development