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Rodriguez-Polo I, Moris N. Using embryo models to understand the development and progression of embryonic lineages: a focus on primordial germ cell development. Cells Tissues Organs 2024:000538275. [PMID: 38479364 DOI: 10.1159/000538275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/05/2024] [Indexed: 05/03/2024] Open
Abstract
BACKGROUND Recapitulating mammalian cell type differentiation in vitro promises to improve our understanding of how these processes happen in vivo, while bringing additional prospects for biomedical applications. The establishment of stem cell-derived embryo models and embryonic organoids, which have experienced explosive growth over the last few years, open new avenues for research due to their scale, reproducibility, and accessibility. Embryo models mimic various developmental stages, exhibit different degrees of complexity, and can be established across species. Since embryo models exhibit multiple lineages organised spatially and temporally, they are likely to provide cellular niches that, to some degree, recapitulate the embryonic setting and enable "co-development" between cell types and neighbouring populations. One example where this is already apparent is in the case of primordial germ cell-like cells (PGCLCs). SUMMARY While directed differentiation protocols enable the efficient generation of high PGCLC numbers, embryo models provide an attractive alternative as they enable the study of interactions of PGCLCs with neighbouring cells, alongside the regulatory molecular and biophysical mechanisms of PGC competency. Additionally, some embryo models can recapitulate post-specification stages of PGC development (including migration or gametogenesis), mimicking the inductive signals pushing PGCLCs to mature and differentiate, and enabling the study of PGCLC development across stages. Therefore, in vitro models may allow us to address questions of cell type differentiation, and PGC development specifically, that have hitherto been out of reach with existing systems. KEY MESSAGE This review evaluates the current advances in stem cell-based embryo models, with a focus on their potential to model cell type-specific differentiation in general, and in particular to address open questions in PGC development and gametogenesis.
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Teague S, Yao L, Heemskerk I. The many dimensions of germline competence. Curr Opin Cell Biol 2023; 85:102259. [PMID: 37852152 PMCID: PMC11123554 DOI: 10.1016/j.ceb.2023.102259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/15/2023] [Accepted: 09/17/2023] [Indexed: 10/20/2023]
Abstract
Primordial germ cell (PGC) specification is the first step in the development of the germline. Recent work has elucidated human-mouse differences in PGC differentiation and identified cell states with enhanced competency for PGC-like cell (PGCLC) differentiation in vitro in both species. However, it remains a subject of debate how different PGC competent states in vitro relate to each other, to embryonic development, and to the origin of PGCs in vivo. Here we review recent literature on human PGCLC differentiation in the context of mouse and non-human primate models. In contrast to what was previously thought, recent work suggests human pluripotent stem cells (hPSCs) are highly germline competent. We argue that paradoxical observations regarding the origin and signaling requirements of hPGCLCs may be due to local cell interactions. These confound assays of competence by generating endogenous signaling gradients and spatially modulating the ability to receive exogenous inductive signals. Furthermore, combinatorial signaling suggests that there is no unique germline competent state: rather than a one-dimensional spectrum of developmental progression, competence should be considered in a higher dimensional landscape of cell states.
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Affiliation(s)
- Seth Teague
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - LiAng Yao
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Idse Heemskerk
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA; Center for Cell Plasticity and Organ Design, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Physics, University of Michigan, Ann Arbor, MI, USA.
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Chen B, Pei D. Genetic clues to reprogramming power and formation of mouse oocyte. Curr Opin Genet Dev 2023; 83:102110. [PMID: 37722148 DOI: 10.1016/j.gde.2023.102110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/05/2023] [Accepted: 07/29/2023] [Indexed: 09/20/2023]
Abstract
Oocyte features the unique capacity to reprogram not only sperm but also somatic nuclei to totipotency, yet the scarcity of oocytes has hindered the exploration and application of their reprogramming ability. In the meanwhile, the formation of oocytes, which involves extensive intracellular alterations and interactions, has also attracted tremendous interest. This review discusses developmental principles and regulatory mechanisms associated with ooplasm reprogramming and oocyte formation from a genetic perspective, with knowledge derived from mouse models. We also discuss future directions, especially to address the lack of insight into the regulatory networks that shape the identity of female germ cells or drive transitions in their developmental programs.
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The people behind the papers - Christopher Cooke and Naomi Moris. Development 2023; 150:dev202273. [PMID: 37694611 DOI: 10.1242/dev.202273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Primordial germ cells (PGCs) are the precursors of gametes, and a presumptive PGC-like cell (PGCLC) population was recently identified in mouse gastruloids. A new paper in Development investigates this population in detail and offers new insight into the signals that contribute to PGC specification and maturation. To hear more about the story, we caught up with first author Christopher Cooke and corresponding author Naomi Moris, Group Leader at the Francis Crick Institute, UK.
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Cooke CB, Barrington C, Baillie-Benson P, Nichols J, Moris N. Gastruloid-derived primordial germ cell-like cells develop dynamically within integrated tissues. Development 2023; 150:dev201790. [PMID: 37526602 PMCID: PMC10508693 DOI: 10.1242/dev.201790] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/24/2023] [Indexed: 08/02/2023]
Abstract
Primordial germ cells (PGCs) are the early embryonic precursors of gametes - sperm and egg cells. PGC-like cells (PGCLCs) can currently be derived in vitro from pluripotent cells exposed to signalling cocktails and aggregated into large embryonic bodies, but these do not recapitulate the native embryonic environment during PGC formation. Here, we show that mouse gastruloids, a three-dimensional in vitro model of gastrulation, contain a population of gastruloid-derived PGCLCs (Gld-PGCLCs) that resemble early PGCs in vivo. Importantly, the conserved organisation of mouse gastruloids leads to coordinated spatial and temporal localisation of Gld-PGCLCs relative to surrounding somatic cells, even in the absence of specific exogenous PGC-specific signalling or extra-embryonic tissues. In gastruloids, self-organised interactions between cells and tissues, including the endodermal epithelium, enables the specification and subsequent maturation of a pool of Gld-PGCLCs. As such, mouse gastruloids represent a new source of PGCLCs in vitro and, owing to their inherent co-development, serve as a novel model to study the dynamics of PGC development within integrated tissue environments.
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Affiliation(s)
- Christopher B. Cooke
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, UK
- Abcam, Discovery Drive, Cambridge Biomedical Campus, Cambridge CB2 0AX, UK
| | | | - Peter Baillie-Benson
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Wellcome Trust – MRC Stem Cell Institute, University of Cambridge, Jeffrey Cheah Biomedical Centre, Puddicombe Way, Cambridge CB2 0AW, UK
- Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 3EG, UK
- Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
| | - Jennifer Nichols
- Wellcome Trust – MRC Stem Cell Institute, University of Cambridge, Jeffrey Cheah Biomedical Centre, Puddicombe Way, Cambridge CB2 0AW, UK
- Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 3EG, UK
- Centre for Trophoblast Research, University of Cambridge, Cambridge, UK
| | - Naomi Moris
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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Wu GMJ, Chen ACH, Yeung WSB, Lee YL. Current progress on in vitro differentiation of ovarian follicles from pluripotent stem cells. Front Cell Dev Biol 2023; 11:1166351. [PMID: 37325555 PMCID: PMC10267358 DOI: 10.3389/fcell.2023.1166351] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Mammalian female reproduction requires a functional ovary. Competence of the ovary is determined by the quality of its basic unit-ovarian follicles. A normal follicle consists of an oocyte enclosed within ovarian follicular cells. In humans and mice, the ovarian follicles are formed at the foetal and the early neonatal stage respectively, and their renewal at the adult stage is controversial. Extensive research emerges recently to produce ovarian follicles in-vitro from different species. Previous reports demonstrated the differentiation of mouse and human pluripotent stem cells into germline cells, termed primordial germ cell-like cells (PGCLCs). The germ cell-specific gene expressions and epigenetic features including global DNA demethylation and histone modifications of the pluripotent stem cells-derived PGCLCs were extensively characterized. The PGCLCs hold potential for forming ovarian follicles or organoids upon cocultured with ovarian somatic cells. Intriguingly, the oocytes isolated from the organoids could be fertilized in-vitro. Based on the knowledge of in-vivo derived pre-granulosa cells, the generation of these cells from pluripotent stem cells termed foetal ovarian somatic cell-like cells was also reported recently. Despite successful in-vitro folliculogenesis from pluripotent stem cells, the efficiency remains low, mainly due to the lack of information on the interaction between PGCLCs and pre-granulosa cells. The establishment of in-vitro pluripotent stem cell-based models paves the way for understanding the critical signalling pathways and molecules during folliculogenesis. This article aims to review the developmental events during in-vivo follicular development and discuss the current progress of generation of PGCLCs, pre-granulosa and theca cells in-vitro.
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Affiliation(s)
- Genie Min Ju Wu
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, China
| | - Andy Chun Hang Chen
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, China
- Shenzhen Key Laboratory of Fertility Regulation, Reproductive Medicine Center, The University of Hong Kong—Shenzhen Hospital, Shenzhen, China
- Centre for Translational Stem Cell Biology, The Hong Kong Science and Technology Park, Hong Kong, China
| | - William Shu Biu Yeung
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, China
- Shenzhen Key Laboratory of Fertility Regulation, Reproductive Medicine Center, The University of Hong Kong—Shenzhen Hospital, Shenzhen, China
- Centre for Translational Stem Cell Biology, The Hong Kong Science and Technology Park, Hong Kong, China
| | - Yin Lau Lee
- Department of Obstetrics and Gynaecology, School of Clinical Medicine, The University of Hong Kong, Hong Kong, China
- Shenzhen Key Laboratory of Fertility Regulation, Reproductive Medicine Center, The University of Hong Kong—Shenzhen Hospital, Shenzhen, China
- Centre for Translational Stem Cell Biology, The Hong Kong Science and Technology Park, Hong Kong, China
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Short telomeres impede germ cell specification by upregulating MAPK and TGFβ signaling. SCIENCE CHINA. LIFE SCIENCES 2023; 66:324-339. [PMID: 36125668 DOI: 10.1007/s11427-022-2151-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 06/21/2022] [Indexed: 10/14/2022]
Abstract
Functional telomeres protect chromosome ends and play important roles in stem cell maintenance and differentiation. Short telomeres negatively impact germ cell development and can contribute to age-associated infertility. Moreover, telomere syndrome resulting from mutations of telomerase or telomere-associated genes exhibits short telomeres and reduced fertility. It remains elusive whether and how telomere lengths affect germ cell specification. We report that functional telomere is required for the coordinated germ cell and somatic cell fate decisions. Using telomerase gene Terc deficient mice as a model, we show that short telomeres restrain germ cell specification of epiblast cells but promote differentiation towards somatic lineage. Short telomeres increase chromatin accessibility to elevate TGFβ and MAPK/ERK signaling for somatic cell differentiation. Notably, elevated Fst expression in TGFβ pathway represses the BMP4-pSmad signaling pathway, thus reducing germ cell formation. Re-elongation of telomeres by targeted knock-in of Terc restores normal chromatin accessibility to suppress TGFβ and MAPK signaling, thereby facilitating germ cell formation. Taken together, our data reveal that functional telomeres are required for germ cell specification by repressing TGFβ and MAPK signaling.
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Jo K, Teague S, Chen B, Khan HA, Freeburne E, Li H, Li B, Ran R, Spence JR, Heemskerk I. Efficient differentiation of human primordial germ cells through geometric control reveals a key role for Nodal signaling. eLife 2022; 11:72811. [PMID: 35394424 PMCID: PMC9106331 DOI: 10.7554/elife.72811] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 04/07/2022] [Indexed: 11/30/2022] Open
Abstract
Human primordial germ cells (hPGCs) form around the time of implantation and are the precursors of eggs and sperm. Many aspects of hPGC specification remain poorly understood because of the inaccessibility of the early postimplantation human embryo for study. Here, we show that micropatterned human pluripotent stem cells (hPSCs) treated with BMP4 give rise to hPGC-like cells (hPGCLC) and use these as a quantitatively reproducible and simple in vitro model to interrogate this important developmental event. We characterize micropatterned hPSCs up to 96 hr and show that hPGCLC populations are stable and continue to mature. By perturbing signaling during hPGCLC differentiation, we identify a previously unappreciated role for Nodal signaling and find that the relative timing and duration of BMP and Nodal signaling are critical parameters controlling the number of hPGCLCs. We formulate a mathematical model for a network of cross-repressive fates driven by Nodal and BMP signaling, which predicts the measured fate patterns after signaling perturbations. Finally, we show that hPSC colony size dictates the efficiency of hPGCLC specification, which led us to dramatically improve the efficiency of hPGCLC differentiation. In humans and other animals, eggs and sperm are unique cells that pass on genetic material to the next generation. They originate from a small group of cells called primordial germ cells that form early in life in the developing embryo. Several different signal molecules including ones known as BMP4, Wnt, and Nodal, instruct certain cells in the embryo to become primordial germ cells. The process by which primordial germ cells are made in humans is very different to how primordial germ cells are made in mice and other so-called model animals that are commonly used in research. This has made it more challenging to uncover the details of the process in humans. Fortunately, new methods have recently been created that mimic aspects of how human embryos develop using human stem cells in a laboratory dish, providing an opportunity to gain a deeper understanding of how human germ cells form. Jo et al. used a technique called micropatterning to control the shape and size of groups of human stem cells growing in a laboratory dish. Treating these cells with a signal known as BMP4 gave rise to cells that resembled primordial germ cells. The team then used this system as a model to study how primordial germ cells form in humans. The experiments found that reducing Wnt signals in stem cells stopped primordial germ cells from forming in response to BMP4, confirming that Wnt signals made by the cells in response to BMP4 are essential. However, this block was overcome by providing the stem cells with another signal called Nodal. This suggests that the role of Wnt signaling in primordial germ cell formation is in part indirect by switching on Nodal in stem cells. Defects in eggs and sperm may lead to infertility, therefore, the findings of Jo et al. have the potential to help researchers develop new fertility treatments that use eggs or sperm grown in a laboratory from the patients’ own stem cells. Such research would benefit from first developing a better understanding of how to make primordial germ cells.
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Affiliation(s)
- Kyoung Jo
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Seth Teague
- Department of Biomedical Engineering, University of Michigan Medical School, Ann Arbor, United States
| | - Bohan Chen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Hina Aftab Khan
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Emily Freeburne
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Hunter Li
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Bolin Li
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Ran Ran
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Jason R Spence
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
| | - Idse Heemskerk
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, United States
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