Project description:Amyotrophic lateral sclerosis and primary lateral sclerosis are two syndromic variants within the motor neurone disease spectrum. Whilst primary lateral sclerosis is associated with loss of upper motor neurons and a more benign disease course up to 17yrs, amyotrophic lateral sclerosis is caused by loss of both upper and lower motor neurons and has an average disease course of 2-3 years. The majority of cases are sporadic, thereby limiting the availability of cellular models for investigating pathogenic disease mechanisms. The aim of the present study was to evaluate fibroblasts as a cellular model for sporadic amyotrophic lateral sclerosis and primary lateral sclerosis, to establish whether disease-related dysregulated biological processes recapitulate those seen in the central nervous system and to elucidate pathways that distinguish between the two disease phenotypes. We used microarray analysis to determine the differences in gene expression between fibroblasts derived from skin biopsies taken from sporadic amyotrophic lateral sclerosis and primary lateral sclerosis neurologically normal human controls
Project description:Amyotrophic lateral sclerosis and primary lateral sclerosis are two syndromic variants within the motor neurone disease spectrum. Whilst primary lateral sclerosis is associated with loss of upper motor neurons and a more benign disease course up to 17yrs, amyotrophic lateral sclerosis is caused by loss of both upper and lower motor neurons and has an average disease course of 2-3 years. The majority of cases are sporadic, thereby limiting the availability of cellular models for investigating pathogenic disease mechanisms. The aim of the present study was to evaluate fibroblasts as a cellular model for sporadic amyotrophic lateral sclerosis and primary lateral sclerosis, to establish whether disease-related dysregulated biological processes recapitulate those seen in the central nervous system and to elucidate pathways that distinguish between the two disease phenotypes.
Project description:High throughput sequencing of poly-A RNA from control- and sporadic Parkinson´s disease patient derived fibroblasts (n=15), induced pluripotent stem cells (n=31) and differentiated midbrain neurons (n=15). Fibroblasts and iPSCs do not show major differences on single gene level. In contrast, midbrain neurons derived from Parkinson´s disease patients show changes known to be associated with neurodegenerative diseases.
Project description:Induced pluripotent stem cells (iPSC) derived from sporadic Parkinson's disease patients and healthy control subjects were used for disease modeling. iPSC were differentiated towards midbrain dopaminergic neurons. For metabolic analysis, midbrain neuronal precursor cells were cultivated in growth medium supplemented with either 1.25 mM [U-13C]-glutamine or 21.25 mM [U-13C]-glucose. Metabolites were extracted and analyzed using GC-MS. The MetaboliteDetector software was used to analyze chromatograms, calculate mass isotopomer distributions (MIDs) and perform relative comparison of metabolite levels.
Project description:Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) sets their identity back to an embryonic age. This presents a fundamental hurdle for modeling late-onset disorders using iPSC-derived cells. We therefore developed a strategy to induce age-like features in multiple iPSC-derived lineages and tested its impact on modeling Parkinson’s disease (PD). We first describe markers that predict fibroblast donor age and observed the loss of these age-related markers following iPSC induction and re-differentiation into fibroblasts. Remarkably, age-related markers were readily induced in iPSC-derived fibroblasts or neurons following exposure to progerin including dopamine neuron-specific phenotypes such as neuromelanin accumulation. Induced aging in PD-iPSC-derived dopamine neurons revealed disease phenotypes requiring both aging and genetic susceptibility such as frank dendrite degeneration, progressive loss of tyrosine-hydroxylase expression and enlarged mitochondria or Lewy body-precursor inclusions. Our study presents a strategy for inducing age-related cellular properties and enables the modeling of late-onset disease features. Induced pluripotent stem cell-derived midbrain dopamine neurons from a young and old donor overexpressing either GFP or Progerin.
Project description:Our understanding of Alzheimer’s disease (AD) pathogenesis is currently limited by difficulties in obtaining live neurons from patients and the inability to model the sporadic form of AD. It may be possible to overcome these challenges by reprogramming primary cells from patients into induced pluripotent stem cells (iPSCs). We reprogrammed primary fibroblasts from two patients with familial AD (both caused by a duplication of APP1, APPDp), two with sporadic AD (sAD1, 2) and two non-demented control individuals (NDCs) into iPSC lines. Neurons from differentiated cultures were FACS-purified and characterized. Purified cultures contained >90% neurons, clustered with fetal brain mRNA samples by microarray criteria, and could form functional synaptic contacts. Virtually all cells exhibited normal electrophysiological activity. Relative to controls, iPSC-derived, purified neurons from the two APPDp patients and patient sAD2 exhibited significantly higher levels of secreted Aβ1-40, phospho-tauThr231 (pTau) and active GSK3β (aGSK3β). Neurons from APPDp and sAD2 patients also accumulated large Rab5-positive early endosomes compared to controls. Treatment of purified neurons with β-secretase inhibitors, but not g-secretase inhibitors, caused significant reductions in pTau and aGSK3β levels. These results suggest a direct relationship between APP proteolytic processing, but not Aβ, in GSK3β activation and tau phosphorylation in human neurons. Additionally, we observed that neurons with the genome of one sAD patient exhibited the phenotypes seen in familial AD samples. More generally, we demonstrate that iPSC technology can be used to observe phenotypes relevant to AD, even though it can take decades for overt disease to manifest in patients. Total RNA extracted from normal hIPSCs, Alzheimer's patient derived hIPSCs, neurons differentiated from hIPSCs, fetal brain, fetal heart, fetal liver and fetal lung
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.
Project description:Psychological, psychosocial and physical stress are major risk factors, which enhance the development of sporadic late-onset Alzheimer`s disease. The chronic unpredictable mild stress model mimics those risk factors and triggers signs of neurodegeneration and neuropathological features of sporadic AD such as tau hyperphosphorylation and enhanced amyloid beta generation. The study investigated the impact of chronic unpredictable mild stress on signs of neurodegeneration by analyzing hippocampal gene expression with whole genome microarray gene expression profiling.
Project description:The discovery of cell-free micro-RNAs in body fluids has made them a promising biomarker target in the field of neurodegenerative diseases. Although they have been reported to be differentially expressed in biofluids and tissue from sporadic Parkinson’s disease patients, it remains unclear whether similar observations can be made in patients with genetic forms of the disease. Since induced pluripotent stem cell derived neurons represent a widely used research model for both sporadic and familial Parkinson’s disease, we sought to assess the usability of this model for the identification of differentially expressed cell-free micro-RNAs in the context of the Parkinson’s disease related LRRK2 G2019S mutation in a proof-of-concept study. We isolated extracellular vesicles carrying cell-free RNA from patient-derived induced pluripotent stem cell lines carrying the LRRK2 G2019S mutation and their gene corrected isogenic controls. After generation of small-RNA libraries and differential expression analysis, we validated fourteen micro-RNAs in an independent batch of cell-free and cellular RNA via RT-qPCR. Finally, we selected eleven differentially expressed micro-RNAs from our cell culture experiments and quantified their expression levels in cerebrospinal fluid derived from two LRRK2 G2019S patients and two healthy controls.