Project description:The idea that stem cell therapies work only via cell replacement is challenged by the observation of consistent intercellular molecule exchange between the graft and the host. Here we defined a mechanism of cellular signaling by which neural stem/precursor cells (NPCs) communicate with the microenvironment via extracellular vesicles (EVs), and we elucidated its molecular signature and function. We observed cytokine-regulated pathways that sort proteins and mRNAs into EVs. We described induction of interferon gamma (IFN-?) pathway in NPCs exposed to proinflammatory cytokines that is mirrored in EVs. We showed that IFN-? bound to EVs through Ifngr1 activates Stat1 in target cells. Finally, we demonstrated that endogenous Stat1 and Ifngr1 in target cells are indispensable to sustain the activation of Stat1 signaling by EV-associated IFN-?/Ifngr1 complexes. Our study identifies a mechanism of cellular signaling regulated by EV-associated IFN-?/Ifngr1 complexes, which grafted stem cells may use to communicate with the host immune system. polyA RNA profiling of Neural Stem/Progenitor cells (NPCs) cultured in basal/Th1/Th2 conditions, of Exosomes derived from NPCs cultured in basal/Th1/Th2 conditions and of EVs derived from NPCs cultured in Basal/Th1/Th2 conditions. Total RNA was purified using Trizol. Purity and integrity were confirmed by BioAnalyser (Agilent). Paired End library construction and poly-A selection were performed by EASIH (The Eastern Sequence and Informatics Hub, University of Cambridge, Cambridge) according to the Illumina standard protocol. Sequencing was performed by EASIH using Illumina GAII.
Project description:The association between macrocephaly and autism spectrum disorder (ASD) suggests that the mechanisms underlying excessive neural growth could contribute to ASD pathogenesis. Consistently, neural progenitor cells (NPCs) derived from induced pluripotent stem cells (iPSCs) of ASD individuals with early developmental brain enlargement are inherently more proliferative than control NPCs. Here, we show that hiPSC-derived NPCs from ASD individuals with macrocephaly display an altered DNA replication program and increased DNA damage. When compared to the control NPCs, high throughput genome-wide translocation sequencing (HTGTS) demonstrates that ASD-derived NPCs harbored elevated DNA double-strand breaks in replication stress-susceptible genes, some of which are associated with ASD pathogenesis. Our results provide a mechanism linking hyperproliferation of NPCs with the pathogenesis of ASD by disrupting long neural genes involved in cell-cell adhesion and migration.
Project description:The association between macrocephaly and autism spectrum disorder (ASD) suggests that the mechanisms underlying excessive neural growth could contribute to ASD pathogenesis. Consistently, neural progenitor cells (NPCs) derived from induced pluripotent stem cells (iPSCs) of ASD individuals with early developmental brain enlargement are inherently more proliferative than control NPCs. Here, we show that hiPSC-derived NPCs from ASD individuals with macrocephaly display an altered DNA replication program and increased DNA damage. When compared to the control NPCs, high throughput genome-wide translocation sequencing (HTGTS) demonstrates that ASD-derived NPCs harbored elevated DNA double-strand breaks in replication stress-susceptible genes, some of which are associated with ASD pathogenesis. Our results provide a mechanism linking hyperproliferation of NPCs with the pathogenesis of ASD by disrupting long neural genes involved in cell-cell adhesion and migration.
Project description:N6-methyladenosine (m6A) modification of mRNA is emerging as a vital mechanism regulating RNA function. Here, we show that fragile X mental retardation protein (FMRP), an RNA-binding protein, reads m6A to regulate nuclear export of methylated mRNA targets during neural stem cell differentiation. In Fmr1 KO mice neural progenitors show delayed cell cycle exit and differentiation, resulting in their progressive accumulation in the ventricular and subventricular zones. RNA-seq of neural precursor cells (NPCs) from Fmr1 KO mice and m6A-seq uncovered nuclear retention of m6A-modified FMRP target mRNAs involved in regulating neural differentiation, including components of Notch and Hedgehog signaling pathways. Analysis of NPCs from Mettl14 cKO mice, which are devoid of m6A, revealed that methylation of RNAs promotes their nuclear export through CRM1. Altogether, our findings suggest that FMRP reads and facilitates nuclear export of m6A-modified mRNAs to regulate neural stem cell differentiation, contributing to Fragile X syndrome.
