Biology subjects

Woldegebriel, R.

Publications and source records attributed to Woldegebriel, R..

3 recordsLinked to original sources

bioRxiv2023

Characterization of cortical neurodevelopment in vitro using gene expression and morphology profiles from single cells

AbstractDifferentiation of induced pluripotent stem cells (iPSC) towards neuronal lineages has enabled diverse cellular models of human neurodevelopment and related disorders. However, in vitro differentiation is a variable process that frequently leads to heterogeneous cell populations that may confound disease-relevant phenotypes. Here, we report a thorough characterization of cortical neuron differentiation from iPSCs using joint profiling of neuronal morphology and transcriptomics in single cells. We assayed 60,000 developing neurons across three timepoints with CellPainting, a high-content imaging method, and single-cell RNA-sequencing (scRNA-seq). By modeling the relationship between morphological features and gene expression within our differentiation system, we annotated image-based features with biological functions and found that while phenotypes related to cell morphology capture broader neuronal classes than scRNA-seq, they enhance our ability to quantify the biological processes that drive neuronal differentiation over time, such as mitochondrial function and cell cycle. Further, we found that while over 60% of the cells match those seen in the fetal brain, 28% represented metabolically abnormal cell states and broader neuronal classes specific to in vitro cells. Finally, we show that specific subtypes of iPSC-derived cortical neurons are a relevant model for a range of brain-related complex traits, including schizophrenia and bipolar disorder, highlighting the potential of multi-modal single cell phenotyping for disease modeling.

genomics↗

bioRxiv2021

Peripheral neuropathy linked mRNA export factor GANP reshapes gene regulation in human motor neurons

Loss-of-function of the mRNA export protein GANP (MCM3AP gene) cause early-onset sensorimotor neuropathy, characterised by axonal degeneration in long peripheral nerves. GANP functions as a scaffold at nuclear pore complexes, contributing to selective nuclear export of mRNAs. Here, we aimed to identify motor neuron specific transcripts that are regulated by GANP and may be limiting for local protein synthesis in motor neuron axons. We compared motor neurons with a gene edited mutation in the Sac3 mRNA binding domain of GANP to isogenic controls. We also examined patient-derived motor neurons. RNA sequencing of motor neurons as well as nuclear and axonal subcompartments showed that mutant GANP had a profound effect on motor neuron transcriptomes, with alterations in nearly 40 percent of all expressed genes and broad changes in splicing. Expression changes in multiple genes critical for neuronal functions, combined with compensatory upregulation of protein synthesis and early-stage metabolic stress genes, indicated that RNA metabolism was abnormal in GANP-deficient motor neurons. Surprisingly, limited evidence was found for large-scale nuclear retention of mRNA. This first study of neuropathy-linked GANP defects in human motor neurons shows that GANP has a wide gene regulatory role in a disease-relevant cell type that requires long-distance mRNA transport.

neuroscience↗

bioRxiv2019

CHCHD10 OR CHCHD2 ARE NOT REQUIRED FOR HUMAN MOTOR NEURON DIFFERENTIATION IN VITRO BUT MODIFY SYNAPTIC TRANSCRIPTOMES

Mitochondrial intermembrane space proteins CHCHD2 and CHCHD10 have roles in diseases affecting motor neurons such as amyotrophic lateral sclerosis, spinal muscular atrophy and axonal neuropathy and in Parkinsons disease, and form a complex of unknown function. Here we address the importance of these two proteins in human motor neurons. We show that gene edited human induced pluripotent stem cells (iPSC) lacking either CHCHD2 or CHCHD10 are viable and can be differentiated into functional motor neurons that fire spontaneous and evoked action potentials. Knockout iPSC and motor neurons sustain mitochondrial ultrastructure and show reciprocal compensatory increases in CHCHD2 or CHCHD10. Knockout motor neurons have largely overlapping transcriptome profiles compared to isogenic control line, in particular for synaptic gene expression. Our results show that absence of CHCHD2 or CHCHD10 does not disrupt functionality, but induces similar modifications in human motor neurons. Thus pathogenic mechanisms may involve loss of synaptic function.

neuroscience↗