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Bulger EA, Muncie-Vasic I, Libby ARG, McDevitt TC, Bruneau BG. TBXT dose sensitivity and the decoupling of nascent mesoderm specification from EMT progression in 2D human gastruloids. Development 2024; 151:dev202516. [PMID: 38411343 PMCID: PMC11006400 DOI: 10.1242/dev.202516] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 02/21/2024] [Indexed: 02/28/2024]
Abstract
In the nascent mesoderm, TBXT expression must be precisely regulated to ensure that cells exit the primitive streak and pattern the anterior-posterior axis, but how varying dosage informs morphogenesis is not well understood. In this study, we define the transcriptional consequences of TBXT dosage reduction during early human gastrulation using human induced pluripotent stem cell models of gastrulation and mesoderm differentiation. Multi-omic single-nucleus RNA and single-nucleus ATAC sequencing of 2D gastruloids comprising wild-type, TBXT heterozygous or TBXT null human induced pluripotent stem cells reveal that varying TBXT dosage does not compromise the ability of a cell to differentiate into nascent mesoderm, but instead directly influences the temporal progression of the epithelial-to-mesenchymal transition with wild type transitioning first, followed by TBXT heterozygous and then TBXT null. By differentiating cells into nascent mesoderm in a monolayer format, we further illustrate that TBXT dosage directly impacts the persistence of junctional proteins and cell-cell adhesions. These results demonstrate that epithelial-to-mesenchymal transition progression can be decoupled from the acquisition of mesodermal identity in the early gastrula and shed light on the mechanisms underlying human embryogenesis.
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Affiliation(s)
- Emily A. Bulger
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA 94158, USA
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, CA 94158, USA
| | - Ivana Muncie-Vasic
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA 94158, USA
- UC Berkeley-UC San Francisco Graduate Program in Bioengineering, University of California, San Francisco, San Francisco, CA 94158, USA and University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ashley R. G. Libby
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA 94158, USA
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, CA 94158, USA
| | - Todd C. McDevitt
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - Benoit G. Bruneau
- Gladstone Institute of Cardiovascular Disease, Gladstone Institutes, San Francisco, CA 94158, USA
- Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA 94158, USA
- Department of Pediatrics, University of California, San Francisco, CA 94158, USA
- Institute for Human Genetics, University of California, San Francisco, CA 94158, USA
- Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94158, USA
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Bulger EA, Muncie-Vasic I, Libby AR, McDevitt TC, Bruneau BG. TBXT dose sensitivity and the decoupling of nascent mesoderm specification from EMT progression in 2D human gastruloids. bioRxiv 2023:2023.11.06.565933. [PMID: 37986746 PMCID: PMC10659276 DOI: 10.1101/2023.11.06.565933] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
In the nascent mesoderm, levels of Brachyury (TBXT) expression must be precisely regulated to ensure cells exit the primitive streak and pattern the anterior-posterior axis, but how this varying dosage informs morphogenesis is not well understood. In this study, we define the transcriptional consequences of TBXT dose reduction during early human gastrulation using human induced pluripotent stem cell (hiPSC)-based models of gastrulation and mesoderm differentiation. Multiomic single-nucleus RNA and single-nucleus ATAC sequencing of 2D gastruloids comprised of WT, TBXT heterozygous (TBXT-Het), or TBXT null (TBXT-KO) hiPSCs reveal that varying TBXT dosage does not compromise a cell's ability to differentiate into nascent mesoderm, but that the loss of TBXT significantly delays the temporal progression of the epithelial to mesenchymal transition (EMT). This delay is dependent on TBXT dose, as cells heterozygous for TBXT proceed with EMT at an intermediate pace relative to WT or TBXT-KO. By differentiating iPSCs of the allelic series into nascent mesoderm in a monolayer format, we further illustrate that TBXT dose directly impacts the persistence of junctional proteins and cell-cell adhesions. These results demonstrate that EMT progression can be decoupled from the acquisition of mesodermal identity in the early gastrula and shed light on the mechanisms underlying human embryogenesis.
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Affiliation(s)
- Emily A. Bulger
- Gladstone Institutes, San Francisco, CA
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, CA
| | - Ivana Muncie-Vasic
- Gladstone Institutes, San Francisco, CA
- UC Berkeley-UC San Francisco Graduate Program in Bioengineering, San Francisco, CA
| | - Ashley R.G. Libby
- Gladstone Institutes, San Francisco, CA
- Developmental and Stem Cell Biology Graduate Program, University of California, San Francisco, CA
| | - Todd C. McDevitt
- Gladstone Institutes, San Francisco, CA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA
| | - Benoit G. Bruneau
- Gladstone Institutes, San Francisco, CA
- Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA
- Department of Pediatrics, University of California, San Francisco, CA, USA
- Institute for Human Genetics, University of California, San Francisco, CA
- Eli and Edythe Broad Center for Regeneration Medicine and Stem Cell Research, University of California, San Francisco
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