Project description:Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease of the central nervous system (CNS), resulting in neurological disability that worsens over time. While progress has been made in defining the immune system’s role in MS pathophysiology, the contribution of intrinsic CNS-cell dysfunction remains unclear. Here, we generated a collection of iPSC lines from people with MS spanning diverse clinical subtypes and differentiated them into glia-enriched cultures. Using single-cell transcriptomic profiling and orthogonal analyses, we observed several distinguishing characteristics of MS cultures pointing to glia-intrinsic disease mechanisms. We found that primary progressive MS-derived cultures contained fewer oligodendrocytes. Moreover, MS-derived oligodendrocyte lineage cells and astrocytes showed increased expression of immune and inflammatory genes, matching those of glia from MS postmortem brains. Thus, iPSC-derived MS models provide a unique platform for dissecting glial contributions to disease phenotypes independent of the peripheral immune system and identify potential glia-specific targets for therapeutic intervention.
Project description:To differentiate, characterize and examine intrinsic phenotypes of C9orf72 ALS/FTD patient-derived induced pluripotent stem cells into microglia (iPSC-MG). Moderate molecular and functional differences were observed in C9orf72 iPSC-MG mono-cultures despite the presence of C9orf72 pathological features.
Project description:Tuberous sclerosis complex (TSC) is a rare neurodevelopmental disorder resulting from autosomal dominant mutations in the TSC1 or TSC2 genes, leading to a hyperactivated mammalian target of rapamycin (mTOR) pathway, and gray and white matter defects in the brain. To study the involvement of neuron-glia interactions in TSC phenotypes, we generated TSC patient induced pluripotent stem cell (iPSC)-derived cortical neuronal and oligodendrocyte (OL) cultures. TSC neuron mono-cultures showed increased network activity, as measured by calcium transients and action potential firing, and increased dendritic branching. However, in co-cultures with OLs, neuronal defects became more apparent, showing cellular hypertrophy and increased axonal density. In addition, TSC neuron-OL co-cultures showed increased OL cell proliferation and decreased OL maturation. Pharmacological intervention with the mTOR regulator rapamycin suppressed these defects. Our patient iPSC-based model, therefore, shows a complex cellular TSC phenotype arising from the interaction of neuronal and glial cells and provides a platform for TSC disease modeling and drug development.
Project description:Multiple sclerosis (MS) is the most frequent demyelinating disease and despite significant advances in the immunotherapy, disease progression still cannot be prevented. Promotion of remyelination, an endogenous repair process, represents a promising new treatment approach. However, spontaneous remyelination frequently fails in MS lesions due to an impaired differentiation of progenitor cells into mature, myelinating oligodendrocytes. Intrinsic oligodendroglial and extrinsic inflammatory factors may contribute to this differentiation block. Therefore, we compared induced pluripotent stem cell (iPSC)-derived oligodendrocytes (hiOL) from MS patients and healthy controls as well as their response to extrinsic factors. While functional capabilities or proteome compostion of both cell types were virtually indistinguishable, we discovered that Interferon-gamma (IFNγ) producing immune cells significantly impaired oligodendroglial differentiation and observed no differences in the functional capabilities or the proteome. In summary, these data indicate that the oligodendroglial differentiation block is not due to intrinsic oligodendroglial factors, but rather caused by the inflammatory environment present in MS lesions. These findings may contribute to the development of remyelination promoting strategies in MS.
Project description:Amyotrophic lateral sclerosis is a fatal neurodegenerative disorder primarily characterized by motor neuron degeneration with additional involvement of non-neuronal cells, in particular, microglia. In our previous work, we have established protocols for the differentiation of iPSC-derived spinal motor neurons and microglia. Here, we combine both cell lineages and establish a novel co-culture of iPSC-derived motor neurons and microglia, which is compatible with motor neuron identity and function. Co-cultured microglia express key microglial markers and transcriptomically resemble primary human microglia, have highly dynamic ramifications, are phagocytic, release various cytokines and respond to stimulation. Further, they express key amyotrophic lateral sclerosis-associated genes and release disease-relevant biomarkers. This novel and authentic human model system facilitates the study of physiological motor neuron-microglia crosstalk and permits the investigation of non-cell-autonomous phenotypes in amyotrophic lateral sclerosis.
Project description:Autism spectrum disorder (ASD) is an early onset neurodevelopmental disorder, which is characterized by disturbances of brain function and behavioral deficits in core areas of impaired reciprocal socialization, impairment in communication skills, and repetitive or restrictive interests and behaviors. ASD is known to have a significant genetic risk, but the underlying genetic variation can be attributed to hundreds of genes. The molecular and pathophysiologic basis of ASD remains elusive because of its genetic heterogeneity and complexity, its high comorbidity with other diseases, and the paucity of brain tissue for study. The invasive nature of collecting primary neuronal tissue from patients might be circumvented through reprogramming peripheral cells to induced pluripotent stem cells (iPSCs), which are able to generate live neurons carrying the genetic variants of disease. This breakthrough allows us to access the cellular and molecular phenotypes of patients with âintrinsic autismâ, that is patients without known genetic disorders or identifiable syndromes or malformations. To do this, we studied a relatively homogeneous patient population of boys with intrinsic autism by excluding patients with known genetic disease or recognizable phenotypes or syndromes, as well as those with profound mental retardation or primary seizure disorders. We generated iPSCs from patients with intrinsic autism, their unaffected male siblings and age-, and sex-matched unaffected controls. And these stem cells were subsequently differentiated into electrophysiologically active neurons. The expression profile for autistic and their unaffected siblings' iPSC-derived neurons were compared. A distinct expression profile was found between autism and sib control. The significantly differentially expressed genes (> 2-fold, FDR < 0.05) in autistic iPSC-derived neurons were significantly enriched for processes related to synaptic transmission, such as neuroactive ligand-receptor signaling and extracellular matrix interactions (FDR < 0.05), and were significantly enriched for genes previously associated with ASD (p < 0.05). Our findings suggest approaches such as iPSC-derived neurons will be an important method to obtain tissue for study that appropriately recapitulates the complex dynamics of an autistic neural cell. We generated induced pluripotent stem cells (iPSCs) from male patients with intrinsic autism, their unaffected male siblings, and age-, and sex-matched unaffected controls. And these stem cells were subsequently differentiated into electrophysiologically active neurons following 80 days of post-mitotic neural differentiation. These samples, including fibroblast, iPSC, iPSC-derived neural progenitors (NPC) and iPSC-derived neurons, were analyzed for the change of gene expression profile by whole genome microarray.
Project description:Disruption of protein homeostasis plays an essential role in neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). One strategy for restoring protein homeostasis and protecting neurons is to de-repress autophagy by disrupting the inhibitory BECN1/BCL2 complex, which has been shown to improve healthspan and lifespan in mice. We screened small molecule BH3 mimetics using an induced pluripotent stem cell (iPSC)-based model of ALS with a FUS mutation and identified obatoclax rescued neurons at by reducing cytoplasmic FUS levels, restoring protein homeostasis, and reducing degeneration.
Project description:Mononuclear phagocytes are key regulators of both tissue damage and repair in neuroinflammatory conditions such as multiple sclerosis (MS). To examine divergent phagocyte phenotypes in the inflamed central nervous system (CNS) we introduce an in vivo imaging approach combined with RNAseq and proteomics that allows us to temporally and spatially resolve the evolution of phagocyte polarization in a murine MS model. We show that the initial pro-inflammatory polarization of phagocytes is established after spinal cord entry and critically depends on the compartment they enter. Guided by signals from the CNS environment individual phagocytes then switch their phenotype as lesions move from expansion to resolution. Our study thus provides a first real-time analysis of the temporo-spatial determinants and regulatory principles of phagocyte specification in the inflamed CNS.
Project description:The role of central nervous system (CNS) glia in sustaining self-autonomous inflammation and driving clinical progression in multiple sclerosis is attracting increasing scientific interest. Here, we applied a single transcription factor (SOX10)-based protocol for accelerating oligodendrocyte differentiation from human induced pluripotent stem cell (hiPSC)-derived neural precursor cells to produce three dimensional, multilineage organoids integrating submillimetric self-organizing forebrain organoids (consisting of neurons, astrocytes, oligodendrocyte precursors cells, and myelinating oligodendrocytes). To achieve an immunocompetent organotypic model, hiPSC-derived microglia was also incorporated. Within an 8-week time frame, organoids reproducibly generated a rich diversity of mature cell types, with single-cell transcriptional profiles similar to the human adult brain. This cellular system is able to respond to complex inflammatory stimuli and to properly mimic macroglia-microglia neurodegenerative phenotypes and crosstalk, as seen in chronic active multiple sclerosis. The results obtained pave the way for the implementation of this novel 3D model in the identification of druggable targets for inflammatory neurodegeneration as drug screening platform.
Project description:Induced pluripotent stem cell (iPSC)-derived dopamine neurons provide an opportunity to model Parkinson’s disease (PD) but neuronal cultures are confounded by cellular heterogeneity. By applying high-resolution single cell transcriptomic analyses to Parkinson’s iPSC-derived dopamine neurons carrying the GBA-N370S risk variant, we exploited intra-culture cellular heterogeneity to identify a progressive axis of gene expression variation leading to endoplasmic reticulum stress. Analysis of genes differentially-expressed (DE) along this axis identified the transcriptional repressor histone deacetylase 4 (HDAC4) as an upstream regulator of disease progression. HDAC4 was mislocalized to the nucleus in PD iPSC-derived dopamine neurons and repressed genes early in the disease axis, leading to late deficits in protein homeostasis. Treatment of iPSC-derived dopamine neurons with compounds known to modulate HDAC4 activity upregulated genes early in the DE axis, and corrected Parkinson’s-related cellular phenotypes. Our study demonstrates how single cell transcriptomics can exploit cellular heterogeneity to reveal disease mechanisms and identify therapeutic targets.