Medulloblastoma (MB) is the most common malignant primary pediatric brain tumor and is divided into 4 subtypes based on different genomic alterations and gene expression profiles. This extensive heterogeneity has made it difficult to assess the functional relevance of genes to malignant progression. For example, expression of the transcription factor, Orthodenticle homeobox2 (OTX2) is frequently upregulated in multiple MB variants; however, its role may be subtype-specific. We recently demonstrated that neural precursors derived from transformed human embryonic stem cells (trans-hENs), but not their normal counterparts (hENs), resemble Groups 3 and 4 MBs. These trans-hENs also have >10-fold expression of OTX2. Therefore, we hypothesize that OTX2 has cell context-dependent functions in MB and using both normal and trans-hENs, we can delineate its specific roles in MB progression. Parallel experiments with MB cells revealed that OTX2 exerts inhibitory effects on hEN and sonic hedgehog (SHH) MB cells by regulating growth, self-renewal and migration in vitro and tumor growth in vivo. Overexpression of OTX2 was accompanied by a decrease in expression of pluripotent genes such as SOX2. This was supported by exogenous introduction of SOX2 in OTX2+ SHH MB and hENs that rescued the OTX2 induced cellular deficits including self-renewal and cell migration. In contrast, OTX2 is oncogenic and promotes self-renewal of trans-hENs and Group 3 and 4 MBs by modulating expression of genes related to neurodevelopment and axonal guidance. OTX2 may play a central role in regulating the balance between self-renewal and differentiation in these aggressive MB cells. Our studies underscore the value of hESC derivatives as alternatives to cell lines and heterogeneous patient samples for investigating the contribution of key developmental regulators to MB progression. Using the neural derivatives of hESCs, we have demonstrated a novel role for OTX2 in self-renewal and migration of hENs and MB cells. Moreover, our results reveal a cell context-dependent link between OTX2 and pluripotent genes. The association between OTX2 and axonal guidance genes is important for its oncogenic role and may potentially be exploited for managing drug resistant stem cell and highly motile cellular populations in the most aggressive Group 3 and 4 MB subtypes. / February 2017

A proteína prion celular (PrPC) consiste em uma glicoproteína de membrana que atua como receptora para diversas moléculas, desencadeando sinais intracelulares. Ao interagir com a co-chaperona STIP1, PrPC promove a autorrenovação e proliferação de células-tronco/progenitoras neurais (NSPCs) durante a fase embrionária. De fato, PrPC tem se destacado por sua participação na neurogênese embrionária e adulta, porém o papel de sua interação com a proteína STIP1 na neurogênese adulta permanece obscuro. Deste modo, o presente trabalho adotou abordagens in vitro para avaliação do complexo PrPC-STIP1 em processos celulares que culminam na neurogênese adulta. Para isso, culturas primárias de NSPCs de camundongos deficientes (Prnp-/-) e tipo-selvagens (Prnp+/+) para PrPC foram realizadas, e a cultura foi devidamente padronizada e caracterizada. Através de ensaios de autorrenovação, proliferação e migração celular sugere-se que PrPC promove estes eventos celulares independentemente de STIP1, e que possivelmente a proteína laminina seja um alvo crítico para migração via PrPC. / Cellular prion protein (PrPC) consists in a membrane glycoprotein that acts as a receptor to several molecules, triggering intracellular signals. By interacting with co-chaperone STIP1, PrPC promotes self-renewal and proliferation of neural stem/progenitor cells (NSPCs) during embryonic stage. Indeed, PrPC has excelled for its participation in embryonic and adult neurogenesis, but the role of its interaction with STIP1 protein in adult neurogenesis remains unclear. Thus, herein it was adopted in vitro approaches in order to evaluate the PrPC-STIP1 complex on cellular processes that culminate in adult neurogenesis. In order to assess that, NSPC primary cultures of PrPC deficient (Prnp-/-) and wild-type (Prnp+/+) mice were performed, and the culture was properly standardized and characterized. Through self-renewal, proliferation and cell migration assays, it was suggested that PrPC promotes these cellular events regardless of STIP1, and possibly the laminin protein is a critical target for migration via PrPC.

A proteína prion celular (PrPC) consiste em uma glicoproteína de membrana que atua como receptora para diversas moléculas, desencadeando sinais intracelulares. Ao interagir com a co-chaperona STIP1, PrPC promove a autorrenovação e proliferação de células-tronco/progenitoras neurais (NSPCs) durante a fase embrionária. De fato, PrPC tem se destacado por sua participação na neurogênese embrionária e adulta, porém o papel de sua interação com a proteína STIP1 na neurogênese adulta permanece obscuro. Deste modo, o presente trabalho adotou abordagens in vitro para avaliação do complexo PrPC-STIP1 em processos celulares que culminam na neurogênese adulta. Para isso, culturas primárias de NSPCs de camundongos deficientes (Prnp-/-) e tipo-selvagens (Prnp+/+) para PrPC foram realizadas, e a cultura foi devidamente padronizada e caracterizada. Através de ensaios de autorrenovação, proliferação e migração celular sugere-se que PrPC promove estes eventos celulares independentemente de STIP1, e que possivelmente a proteína laminina seja um alvo crítico para migração via PrPC. / Cellular prion protein (PrPC) consists in a membrane glycoprotein that acts as a receptor to several molecules, triggering intracellular signals. By interacting with co-chaperone STIP1, PrPC promotes self-renewal and proliferation of neural stem/progenitor cells (NSPCs) during embryonic stage. Indeed, PrPC has excelled for its participation in embryonic and adult neurogenesis, but the role of its interaction with STIP1 protein in adult neurogenesis remains unclear. Thus, herein it was adopted in vitro approaches in order to evaluate the PrPC-STIP1 complex on cellular processes that culminate in adult neurogenesis. In order to assess that, NSPC primary cultures of PrPC deficient (Prnp-/-) and wild-type (Prnp+/+) mice were performed, and the culture was properly standardized and characterized. Through self-renewal, proliferation and cell migration assays, it was suggested that PrPC promotes these cellular events regardless of STIP1, and possibly the laminin protein is a critical target for migration via PrPC.

Spinal cord injury (SCI) is complicated injury with serious socioeconomic consequences for the patient and his whole family. Big difficulty cause also extremely high living expenses for the patient with this type of injury. That's why there is a need for therapeutic methods which would help patients after SCI to recover the lost functions and be able at least partially to return to their normal life. Different therapeutic methods are being used for SCI treatment. In this study we used four various types of stem cells: human bone marrow stem cells (hBM-MSCs), human umbilical cord mesenchymal stem cells (hUC-MSCs), neural precursors derived from induced pluripotent stem cells (iPS-NPs) and neural stem cell line derived from human fetal spinal cord tissue (SPC-01). These cells have been transplanted intrathecally or intraspinally 7 days after induction of the experimental model of SCI in the rat. We studied expressions of genes related to neurogenesis, growth factors and inflammation 10 and 28 days after SCI. Our analysis showed significant changes in gene expression 10 days after SCI. Significant up-regulation in expression of vascular endothelial growth factor (Vegf), ciliary neurotrophic factor (Cntf) and interferon regulatory factor 5 (Irf5) were found after transplantation of hBM-MSCs and hUC-...