Project description:A challenge for understanding the development of brain circuits is to identify the factors that instruct neurons to accomplish each developmental step at the appropriate stage. Neuronal maturation follows an intrinsic species-specific developmental pace that is extremely protracted in humans and that is retained during human pluripotent stem cells (hPSCs) differentiations. Using a novel platform that synchronized the generation of cortical neurons from hPSC, we established morphological, functional, and molecular roadmaps of maturation. We found that the temporal unfolding of maturation programs proceeds gradually and is limited by the retention of complex epigenetic signatures. Loss-of-function of multiple such epigenetic factors at the neuron stage triggered precocious molecular and functional maturation. Remarkably, transient pharmacological manipulation of a subset of epigenetic factors, including EZH2, EHMT1/2 and DOT1L, at the progenitor cell stage can prime precursors to reach enhanced molecular and functional signatures of maturity as neurons. Our results indicate that the rate at which neurons mature is set well before neurogenesis through the establishment of an “epigenetic barrier” in progenitor cells that gets slowly erased in neurons, allowing the gradual onset of maturation programs.
Project description:A challenge for understanding the development of brain circuits is to identify the factors that instruct neurons to accomplish each developmental steps at the appropriate stage. Neuronal maturation follows an intrinsic species-specific developmental pace that is extremely protracted in humans and that is retained during human pluripotent stem cells (hPSCs) differentiations. Using a novel platform that synchronized the generation of cortical neurons from hPSC, we established morphological, functional, and molecular roadmaps of maturation. We found that the temporal unfolding of maturation programs proceeds gradually and is limited by the retention of complex epigenetic signatures. Loss-of-function of multiple such epigenetic factors at the neuron stage triggered precocious molecular and functional maturation. Remarkably, transient pharmacological manipulation of a subset of epigenetic factors, including EZH2, EHMT1/2 and DOT1L, at the progenitor cell stage can prime precursors to reach enhanced molecular and functional signatures of maturity as neurons. Our results indicate that the rate at which neurons mature is set well before neurogenesis through the establishment of an “epigenetic barrier” in progenitor cells that gets slowly erased in neurons, allowing the gradual onset of maturation programs.
Project description:A challenge for understanding the development of brain circuits is to identify the factors that instruct neurons to accomplish each developmental steps at the appropriate stage. Neuronal maturation follows an intrinsic species-specific developmental pace that is extremely protracted in humans and that is retained during human pluripotent stem cells (hPSCs) differentiations. Using a novel platform that synchronized the generation of cortical neurons from hPSC, we established morphological, functional, and molecular roadmaps of maturation. We found that the temporal unfolding of maturation programs proceeds gradually and is limited by the retention of complex epigenetic signatures. Loss-of-function of multiple such epigenetic factors at the neuron stage triggered precocious molecular and functional maturation. Remarkably, transient pharmacological manipulation of a subset of epigenetic factors, including EZH2, EHMT1/2 and DOT1L, at the progenitor cell stage can prime precursors to reach enhanced molecular and functional signatures of maturity as neurons. Our results indicate that the rate at which neurons mature is set well before neurogenesis through the establishment of an “epigenetic barrier” in progenitor cells that gets slowly erased in neurons, allowing the gradual onset of maturation programs.
Project description:A challenge for understanding the development of brain circuits is to identify the factors that instruct neurons to accomplish each developmental steps at the appropriate stage. Neuronal maturation follows an intrinsic species-specific developmental pace that is extremely protracted in humans and that is retained during human pluripotent stem cells (hPSCs) differentiations. Using a novel platform that synchronized the generation of cortical neurons from hPSC, we established morphological, functional, and molecular roadmaps of maturation. We found that the temporal unfolding of maturation programs proceeds gradually and is limited by the retention of complex epigenetic signatures. Loss-of-function of multiple such epigenetic factors at the neuron stage triggered precocious molecular and functional maturation. Remarkably, transient pharmacological manipulation of a subset of epigenetic factors, including EZH2, EHMT1/2 and DOT1L, at the progenitor cell stage can prime precursors to reach enhanced molecular and functional signatures of maturity as neurons. Our results indicate that the rate at which neurons mature is set well before neurogenesis through the establishment of an “epigenetic barrier” in progenitor cells that gets slowly erased in neurons, allowing the gradual onset of maturation programs.
Project description:Neuronal development in the human cerebral cortex is considerably prolonged compared to that of other mammals. We explored whether mitochondria influence the species-specific timing of cortical neuron maturation. By comparing human and mouse cortical neuronal maturation at high temporal and cell resolution, we found a slower mitochondria development in human cortical neurons compared with that in the mouse, together with lower mitochondria metabolic activity, particularly that of oxidative phosphorylation. Stimulation of mitochondria metabolism in human neurons resulted in accelerated development in vitro and in vivo, leading to maturation of cells weeks ahead of time, whereas its inhibition in mouse neurons led to decreased rates of maturation. Mitochondria are thus important regulators of the pace of neuronal development underlying human-specific brain neoteny.
Project description:Interactions among neuroglial and vascular components are crucial for retinal angiogenesis and blood-retinal barrier (BRB) maturation. Neuronal synaptic dysfunctions precede vascular abnormalities in many retinal pathologies. However, whether neuronal activity, specifically glutamatergic activity, regulates retinal angiogenesis and BRB maturation remains unclear. Using in vivo genetic studies in mice, single-cell RNA-sequencing and functional validation, we found that deep plexus angiogenesis and paracellular BRB maturation are delayed in Vglut1-/- retinas, where neurons fail to release glutamate. In contrast, deep plexus angiogenesis and paracellular BRB maturation are accelerated in Gnat1-/- retinas, where constitutively depolarized rods release excess glutamate. Mechanistically, Norrin expression and endothelial Norrin/b-catenin signaling are downregulated in Vglut1-/- retinas, and upregulated in Gnat1-/- retinas. Pharmacological activation of endothelial Norrin/ b-catenin signaling in Vglut1-/- retinas rescued both deep plexus angiogenesis and paracellular BRB integrity. Thus, our findings demonstrate that glutamatergic neuronal activity regulates retinal angiogenesis and BRB maturation by modulating Norrin/b-catenin signaling.