Project description:Midbrain dopaminergic (mDA) neurons degenerate in Parkinson's disease and are one of the main targets for cell replacement therapies. A comprehensive view of the signals and cell types contributing to mDA neurogenesis is not yet available. By analyzing the transcriptome of the mouse ventral midbrain at tissue and single-cell level during mDA neurogenesis we found that three recently identified radial glia types (Rgl 1-3) contribute to different key aspects of mDA neurogenesis. While Rgl3 expressed most extracellular matrix components and multiple ligands for various pathways controlling mDA neuron development, such as Wnt and Shh, Rgl1-2 expressed most receptors. Moreover, we found that specific transcription factor networks explain the transcriptome expression profiles and suggest a function for each individual radial glia type.
Project description:RNA-SEQ profiling of mouse whole midbrain and dopaminergic neurons from the mouse mid-brain Murine whole midbrain and murine midbrain dopaminergic neurons
Project description:Embryonic stem (ES) cells were differentiated in culture to midbrain dopaminergic (mDA) progenitors and subjected to ChIP-seq analysis to resolve genome-wide binding sites of forkhead box protein A2 (Foxa2). Foxa2 was found to directly regulate multiple lineage pathways to specify midbrain dopaminergic and floor plate progenitor identity.
Project description:Here we use MeRIP-Seq to analyze global adenosine methylation (m6A) in mRNAs in the midbrain and striatum of Fto-deficient mice. We find that Fto deficiency leads to increased methylation within a subset of mRNAs important for neuronal signaling, including many within the dopaminergic signaling pathway. Collectively, our results show that Fto regulates demethylation of specific mRNAs in vivo, and this activity relates to control of dopaminergic transmission. Profiling of m6A in midbrain and striatum from wild type mice
Project description:N27 cells are dopaminergic neurons derived from rat midbrain and are extensively employed as a model for neurodegeneration. N27 cells were challenged with 2 neurotoxins associated with Manganism (Manganese Chloride;Mn) and Parkinson's Disease (1-methyl-4-phenylpyridinium ion;MPP+). Mn and MPP+ result in movement dysfunction and are mitochondrial toxins particularly affecting complexes I.This study aimed to understand and differentiate the molecular mechanisms underlying Mn and MPP+ mediated dopaminergic insult by evaluating the differential gene expression pattern in the two models
Project description:In order to get a better molecular understanding of human midbrain development, this study defines cell types of the ventral midbrain in both human and mouse as well as stem cell-derived dopaminergic neuron preparations, and reveals the temporal dynamics of key lineages across development and the adult.
Project description:Here we use MeRIP-Seq to analyze global adenosine methylation (m6A) in mRNAs in the midbrain and striatum of Fto-deficient mice. We find that Fto deficiency leads to increased methylation within a subset of mRNAs important for neuronal signaling, including many within the dopaminergic signaling pathway. Collectively, our results show that Fto regulates demethylation of specific mRNAs in vivo, and this activity relates to control of dopaminergic transmission. Profiling of m6A in midbrain and striatum from FTO knockout mice
Project description:Mutations in the SNCA gene cause autosomal dominant Parkinson’s disease (PD), with progressive loss of dopaminergic neurons in the substantia nigra, and accumulation of aggregates of α-synuclein. However, the sequence of molecular events that proceed from the SNCA mutation during development, to its end stage pathology is unknown. Utilising human induced pluripotent stem cells (hiPSCs) with SNCA mutations, we resolved the temporal sequence of pathophysiological events that occur during neuronal differentiation in order to discover the early, and likely causative, events in synucleinopathies. We adapted a small molecule-based protocol that generates highly enriched midbrain dopaminergic (mDA) neurons (>80%). We characterised their molecular identity using single-cell RNA sequencing and their functional identity through the synthesis and secretion of dopamine, the ability to generate action potentials, and form functional synapses and networks. RNA velocity analyses confirmed the developmental transcriptomic trajectory of midbrain neural precursors into different mDA neuronal clusters. To characterise the synucleinopathy, we adopted super-resolution methods to determine the number, size, and structure of aggregates in SNCA-mutant mDA neurons. By day 27 of differentiation, prior to maturation to mDA neurons of molecular and functional identity, we demonstrate the formation of small aggregates; specifically, β-sheet rich oligomeric aggregates, in SNCA-mutant midbrain immature neurons. The aggregation progresses over time to accumulate phosphorylated and fibrillar aggregates. When the midbrain neurons were functional, we observed impaired intracellular calcium signalling, evidenced with an increased basal calcium level and impairments in both cytosolic and mitochondrial calcium rearrangements. Once midbrain identity fully developed, SNCA-mutant neurons exhibited mitochondrial dysfunction, oxidative stress, lysosomal swelling as well as an upregulation of mitophagy and autophagy. In addition, SNCA-mutant neurons displayed pathophysiological excitability, revealed as a depolarised resting membrane potential, an increased input resistance, and impaired firing properties. Ultimately these multiple cellular stresses lead to an increase in cell death by day 62 post-differentiation. Our differentiation paradigm generates an efficient model for studying disease mechanisms in PD, and highlights that protein misfolding to generate intraneuronal oligomers is one of the earliest critical events driving disease in human neurons, rather than a late-stage hallmark of the disease.