Project description:The generation of myotubes from fibroblasts upon forced MyoD expression is a classic example of factor-induced reprogramming in mammals. We recently discovered that additional modulation of signaling pathways with small molecules facilitates reprogramming to more primitive induced muscle progenitor cells (iMPCs). However, the mechanisms by which a single transcription factor drives differentiated cells into distinct developmental states remain unknown. We therefore dissected the transcriptional and epigenetic dynamics of fibroblasts undergoing MyoD-dependent reprogramming to either myotubes or iMPCs using a novel MyoD transgenic model. To this end, we performed ATAC sequencing for Pax7-nGFP positive iMPCs/satellite cells, cells undergoing dedifferentiation (i.e. Dox+FRG) or transdifferentiation (i.e. Dox) and cells overexpressing a wild type MyoD or a mutant MyoD (i.e. MN) in the presence of FRG. Our analyses elucidate the role of MyoD in myogenic reprogramming and derive general principles by which transcription factors and signaling pathways cooperate to rewire cell identity. Our results may also inform on potential therapeutic applications of direct reprogramming.

2021-08-24 | GSE169488 | GEO

Label-free quantification (LFQ) analysis on skeletal muscle stem cells and reprogrammed skeletal muscle stem and progenitor cells

Project description:Direct lineage reprogramming provides a unique system to study cell fate transitions and unearth molecular mechanisms that safeguard cellular identity. We previously reported on direct conversion of mouse fibroblasts into induced myogenic progenitor cells (iMPCs) by transient MyoD overexpression in concert with small molecules treatment. Here we employed integrative multi-omic approaches to delineate the molecular landscape of fibroblast reprogramming into iMPCs in comparison to transdifferentiation into myogenic cells solely by MyoD overexpression. Utilizing bulk RNA-sequencing and mass spectrometry, we uncovered molecular regulators and pathways that endow a myogenic stem cell identity on fibroblasts only in the presence of small molecule treatment. In addition, we demonstrate that Pax7+ cells in iMPCs share molecular attributes with myoblasts, however in addition express unique genes, proteins and pathways that are indicative of a more activated satellite cell-like state in vitro. Collectively, this study charts a molecular blueprint for reprogramming fibroblasts into muscle stem and progenitor cells and further establishes the fidelity of stable iMPC cultures in capturing skeletal muscle regeneration in vitro for disease modeling and basic research applications.

2022-05-19 | PXD029379 | Pride

A self-renewing biomimetic skeletal muscle construct engineered using induced myogenic progenitor cells

Project description:Skeletal muscle is a highly organized and regenerative tissue that maintains its homeostasis primarily by activation and differentiation of muscle stem cells. Mimicking an in vitro skeletal muscle differentiation program that contains self-renewing adult muscle stem cells and aligned myotubes has been challenging. Here, we set out to engineer a biomimetic skeletal muscle construct that can self-regenerate and produce aligned myotubes using induced myogenic progenitor cells (iMPCs), a heterogeneous culture consisting of skeletal muscle stem, progenitor and differentiated cells. Utilizing electrospinning, we fabricated polycaprolactone (PCL) substrates that enabled iMPC-differentiation into aligned myotubes by controlling PCL fiber orientation. Newly-conceived constructs contained highly organized multinucleated myotubes in conjunction with self-renewing muscle stem cells, whose differentiation capacity was augmented by Matrigel supplementation. Additionally, we demonstrate using single cell RNA sequencing (scRNA-seq) that iMPC-derived constructs faithfully recapitulate a step-wise myogenic differentiation program. Notably, when the constructs were subjected to a damaging myonecrotic agent, self-renewing muscle stem cells rapidly differentiated into aligned myotubes, akin to skeletal muscle repair in vivo. Taken together, we report on a novel in vitro system that mirrors myogenic regeneration and muscle fiber alignment, and can serve as a platform to study myogenesis, model muscular dystrophies or perform drug screens.

2023-09-27 | GSE222162 | GEO

Induced muscle progenitor cells [RNA-seq]

Project description:The generation of myotubes from fibroblasts upon forced MyoD expression is a classic example of factor-induced reprogramming in mammals. We recently discovered that additional modulation of signaling pathways with small molecules facilitates reprogramming to more primitive induced muscle progenitor cells (iMPCs). However, the mechanisms by which a single transcription factor drives differentiated cells into distinct developmental states remain unknown. We therefore dissected the transcriptional and epigenetic dynamics of fibroblasts undergoing MyoD-dependent reprogramming to either myotubes or iMPCs using a novel MyoD transgenic model. To this end, we performed RNA-sequencing for Pax7-nGFP positive (including high and low) iMPCs/satellite cells, cells undergoing dedifferentiation (i.e. Dox+FRG) or transdifferentiation (i.e. Dox) and cells overexpressing a wild type MyoD or a mutant MyoD (i.e. MN) in the presence of FRG. Our analyses elucidate the role of MyoD in myogenic reprogramming and derive general principles by which transcription factors and signaling pathways cooperate to rewire cell identity. Our results may also inform on potential therapeutic applications of direct reprogramming.

2021-08-24 | GSE169487 | GEO

Generation of induced oligodendrocyte progenitor cells from human somatic cells

Project description:Generation of induced oligodendrocyte progenitor cells from human somatic cells

| PRJNA533777 | ENA