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Sonsalla G, Malpartida AB, Riedemann T, Gusic M, Rusha E, Bulli G, Najas S, Janjic A, Hersbach BA, Smialowski P, Drukker M, Enard W, Prehn JHM, Prokisch H, Götz M, Masserdotti G. Direct neuronal reprogramming of NDUFS4 patient cells identifies the unfolded protein response as a novel general reprogramming hurdle. Neuron 2024; 112:1117-1132.e9. [PMID: 38266647 PMCID: PMC10994141 DOI: 10.1016/j.neuron.2023.12.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/12/2023] [Accepted: 12/21/2023] [Indexed: 01/26/2024]
Abstract
Mitochondria account for essential cellular pathways, from ATP production to nucleotide metabolism, and their deficits lead to neurological disorders and contribute to the onset of age-related diseases. Direct neuronal reprogramming aims at replacing neurons lost in such conditions, but very little is known about the impact of mitochondrial dysfunction on the direct reprogramming of human cells. Here, we explore the effects of mitochondrial dysfunction on the neuronal reprogramming of induced pluripotent stem cell (iPSC)-derived astrocytes carrying mutations in the NDUFS4 gene, important for Complex I and associated with Leigh syndrome. This led to the identification of the unfolded protein response as a major hurdle in the direct neuronal conversion of not only astrocytes and fibroblasts from patients but also control human astrocytes and fibroblasts. Its transient inhibition potently improves reprogramming by influencing the mitochondria-endoplasmic-reticulum-stress-mediated pathways. Taken together, disease modeling using patient cells unraveled novel general hurdles and ways to overcome these in human astrocyte-to-neuron reprogramming.
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Affiliation(s)
- Giovanna Sonsalla
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany; Graduate School of Systemic Neurosciences, BMC, LMU Munich, Planegg-Martinsried 82152 Germany
| | - Ana Belen Malpartida
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany; International Max Planck Research School (IMPRS) for Molecular Life Sciences, Planegg-Martinsried 82152, Germany
| | - Therese Riedemann
- Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Mirjana Gusic
- Institute of Neurogenomics, Helmholtz Zentrum München, Ingolstaedter Landstraße 1, 85764 Neuherberg, Germany
| | - Ejona Rusha
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany
| | - Giorgia Bulli
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany; Graduate School of Systemic Neurosciences, BMC, LMU Munich, Planegg-Martinsried 82152 Germany
| | - Sonia Najas
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Aleks Janjic
- Anthropology and Human Genomics, Faculty of Biology, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Bob A Hersbach
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany; Graduate School of Systemic Neurosciences, BMC, LMU Munich, Planegg-Martinsried 82152 Germany
| | - Pawel Smialowski
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany; Biomedical Center Munich, Bioinformatic Core Facility, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Micha Drukker
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research (LACDR), Leiden University, Gorlaeus Building, 2333 CC RA, Leiden, the Netherlands
| | - Wolfgang Enard
- Anthropology and Human Genomics, Faculty of Biology, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Jochen H M Prehn
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - Holger Prokisch
- Institute of Neurogenomics, Helmholtz Zentrum München, Ingolstaedter Landstraße 1, 85764 Neuherberg, Germany; Institute of Human Genetics, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | - Magdalena Götz
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany; Excellence Cluster of Systems Neurology (SYNERGY), Munich, Germany.
| | - Giacomo Masserdotti
- Institute for Stem Cell Research, Helmholtz Center Munich, Neuherberg 85764, Germany; Biomedical Center Munich, Physiological Genomics, LMU Munich, Planegg-Martinsried 82152, Germany.
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Bocchi R, Masserdotti G, Götz M. Direct neuronal reprogramming: Fast forward from new concepts toward therapeutic approaches. Neuron 2021:S0896-6273(21)00972-7. [PMID: 34921778 DOI: 10.1016/j.neuron.2021.11.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/25/2021] [Accepted: 11/19/2021] [Indexed: 12/21/2022]
Abstract
Differentiated cells have long been considered fixed in their identity. However, about 20 years ago, the first direct conversion of glial cells into neurons in vitro opened the field of "direct neuronal reprogramming." Since then, neuronal reprogramming has achieved the generation of fully functional, mature neurons with remarkable efficiency, even in diseased brain environments. Beyond their clinical implications, these discoveries provided basic insights into crucial mechanisms underlying conversion of specific cell types into neurons and maintenance of neuronal identity. Here we discuss such principles, including the importance of the starter cell for shaping the outcome of neuronal reprogramming. We further highlight technical concerns for in vivo reprogramming and propose a code of conduct to avoid artifacts and pitfalls. We end by pointing out next challenges for development of less invasive cell replacement therapies for humans.
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Vasan L, Park E, David LA, Fleming T, Schuurmans C. Direct Neuronal Reprogramming: Bridging the Gap Between Basic Science and Clinical Application. Front Cell Dev Biol 2021; 9:681087. [PMID: 34291049 PMCID: PMC8287587 DOI: 10.3389/fcell.2021.681087] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/02/2021] [Indexed: 12/15/2022] Open
Abstract
Direct neuronal reprogramming is an innovative new technology that involves the conversion of somatic cells to induced neurons (iNs) without passing through a pluripotent state. The capacity to make new neurons in the brain, which previously was not achievable, has created great excitement in the field as it has opened the door for the potential treatment of incurable neurodegenerative diseases and brain injuries such as stroke. These neurological disorders are associated with frank neuronal loss, and as new neurons are not made in most of the adult brain, treatment options are limited. Developmental biologists have paved the way for the field of direct neuronal reprogramming by identifying both intrinsic cues, primarily transcription factors (TFs) and miRNAs, and extrinsic cues, including growth factors and other signaling molecules, that induce neurogenesis and specify neuronal subtype identities in the embryonic brain. The striking observation that postmitotic, terminally differentiated somatic cells can be converted to iNs by mis-expression of TFs or miRNAs involved in neural lineage development, and/or by exposure to growth factors or small molecule cocktails that recapitulate the signaling environment of the developing brain, has opened the door to the rapid expansion of new neuronal reprogramming methodologies. Furthermore, the more recent applications of neuronal lineage conversion strategies that target resident glial cells in situ has expanded the clinical potential of direct neuronal reprogramming techniques. Herein, we present an overview of the history, accomplishments, and therapeutic potential of direct neuronal reprogramming as revealed over the last two decades.
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Affiliation(s)
- Lakshmy Vasan
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Eunjee Park
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Luke Ajay David
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Taylor Fleming
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
| | - Carol Schuurmans
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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Rao Z, Wang R, Li S, Shi Y, Mo L, Han S, Yuan J, Jing N, Cheng L. Molecular Mechanisms Underlying Ascl1-Mediated Astrocyte-to-Neuron Conversion. Stem Cell Reports 2021; 16:534-47. [PMID: 33577795 DOI: 10.1016/j.stemcr.2021.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/12/2021] [Accepted: 01/12/2021] [Indexed: 12/19/2022] Open
Abstract
Direct neuronal reprogramming potentially provides valuable sources for cell-based therapies. Proneural gene Ascl1 converts astrocytes into induced neuronal (iN) cells efficiently both in vitro and in vivo. However, the underlying mechanisms are largely unknown. By combining RNA sequencing and chromatin immunoprecipitation followed by high-throughput sequencing, we found that the expression of 1,501 genes was markedly changed during the early stages of Ascl1-induced astrocyte-to-neuron conversion and that the regulatory regions of 107 differentially expressed genes were directly bound by ASCL1. Among Ascl1's direct targets, Klf10 regulates the neuritogenesis of iN cells at the early stage, Myt1 and Myt1l are critical for the electrophysiological maturation of iN cells, and Neurod4 and Chd7 are required for the efficient conversion of astrocytes into neurons. Together, this study provides more insights into understanding the molecular mechanisms underlying Ascl1-mediated astrocyte-to-neuron conversion and will be of value for the application of direct neuronal reprogramming. RNA-seq and ChIP-seq were used to study Ascl1-induced astrocyte-to-neuron conversion Early Klf10 regulates neuritogenesis and electrophysiological properties of iN cells Myt1 and Myt1l are critical for the electrophysiological maturation of iN cells Neurod4 and Chd7 are required for efficient conversion of astrocytes to neurons
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