Pub Date : 2024-08-09DOI: 10.1101/2024.08.09.607306
Valentyn Kyrychenko, Philipp Rensinghoff, Johannes Bulk, Constanze Frey, Stephan Heermann
The visual system is highly specialized and its function is substantially depending on the proper development of the eyes. Early eye development starts with the definition of a single eye field, which is localized within the anterior neural plate (ANP). This single eye field is split consecutively and two optic vesicles emerge at the sides. These vesicles are then transformed into optic cups, out of which the future retinae are differentiating. Holoprosencephaly (HPE) is a frequent developmental forebrain disorder, in which the splitting of ANP domains is hampered. HPE is mostly genetically linked and we recently showed that BMP antagonism is important for the eye field and the telencephalic anlage to split. Excessive BMP induction led to retinal progenitors stuck inside a dysmorphic forebrain. In this study, using the zebrafish as a model, we show with acute CRISPR/ Cas9 analysis in the F0 generation, the necessity of bmp7b and bmpr1ba for proper forebrain development. In Crispants for both genes we found HPE phenotypes, e.g. cyclopia. Further analysis of bmp7b Crispants indicated that predominantly the eye field is affected, rather than the telencephalic precursor domain.
{"title":"Holoprosencephaly and Cyclopia in bmp7b and bmpr1ba Crispant zebrafish","authors":"Valentyn Kyrychenko, Philipp Rensinghoff, Johannes Bulk, Constanze Frey, Stephan Heermann","doi":"10.1101/2024.08.09.607306","DOIUrl":"https://doi.org/10.1101/2024.08.09.607306","url":null,"abstract":"The visual system is highly specialized and its function is substantially depending on the proper development of the eyes. Early eye development starts with the definition of a single eye field, which is localized within the anterior neural plate (ANP). This single eye field is split consecutively and two optic vesicles emerge at the sides. These vesicles are then transformed into optic cups, out of which the future retinae are differentiating. Holoprosencephaly (HPE) is a frequent developmental forebrain disorder, in which the splitting of ANP domains is hampered. HPE is mostly genetically linked and we recently showed that BMP antagonism is important for the eye field and the telencephalic anlage to split. Excessive BMP induction led to retinal progenitors stuck inside a dysmorphic forebrain.\u0000In this study, using the zebrafish as a model, we show with acute CRISPR/ Cas9 analysis in the F0 generation, the necessity of bmp7b and bmpr1ba for proper forebrain development. In Crispants for both genes we found HPE phenotypes, e.g. cyclopia. Further analysis of bmp7b Crispants indicated that predominantly the eye field is affected, rather than the telencephalic precursor domain.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-09DOI: 10.1101/2024.08.09.607329
Johannes Bulk, Valentyn Kyrychenko, Stephan Heermann
Early forebrain development is a fascinating process and the fate of higher brain function but also the fate of visual perception largely depends on it. During gastrulation a single domain for the prospective telencephalon and a single eye field are localized in the anterior most region of the early neuroectoderm, the anterior neural plate (ANP). Importantly, these domains must be split as development proceeds, giving rise to two telencephalic lobes as well as to two optic vesicles, which are transformed into optic cups subsequently. Holoprosencephaly (HPE) unfortunately is a rather frequent developmental disorder of the forebrain, during which the separation of the early precursor domains is hampered. Clinical manifestation can vary a lot, including the accompanying ophthalmologic findings. Here we ask, whether anophthalmia is more severe than cyclopia, both being ophthalmologic findings in HPE. In this brief analysis, we make use of a recently established zebrafish model of HPE in which the early function of BMP antagonists is abrogated by the excessive induction of a BMP ligand. An early induction was resulting in retinal progenitors being stuck in the forebrain with no eye being formed. We attenuated the induction protocol to investigate whether the anophthalmia phenotype could be changed into a cyclopic phenotype. We found synophthalmia and ocular hypotelorism, however, not cyclopia. Based on this we propose that anophthalmia and cyclopia are both the strongest ophthalmologic finding, however, depending on the type of HPE underlying.
{"title":"Different ophthalmologic findings in induced models of Holoprosencephaly in zebrafish","authors":"Johannes Bulk, Valentyn Kyrychenko, Stephan Heermann","doi":"10.1101/2024.08.09.607329","DOIUrl":"https://doi.org/10.1101/2024.08.09.607329","url":null,"abstract":"Early forebrain development is a fascinating process and the fate of higher brain function but also the fate of visual perception largely depends on it. During gastrulation a single domain for the prospective telencephalon and a single eye field are localized in the anterior most region of the early neuroectoderm, the anterior neural plate (ANP). Importantly, these domains must be split as development proceeds, giving rise to two telencephalic lobes as well as to two optic vesicles, which are transformed into optic cups subsequently. Holoprosencephaly (HPE) unfortunately is a rather frequent developmental disorder of the forebrain, during which the separation of the early precursor domains is hampered. Clinical manifestation can vary a lot, including the accompanying ophthalmologic findings. Here we ask, whether anophthalmia is more severe than cyclopia, both being ophthalmologic findings in HPE. In this brief analysis, we make use of a recently established zebrafish model of HPE in which the early function of BMP antagonists is abrogated by the excessive induction of a BMP ligand. An early induction was resulting in retinal progenitors being stuck in the forebrain with no eye being formed. We attenuated the induction protocol to investigate whether the anophthalmia phenotype could be changed into a cyclopic phenotype. We found synophthalmia and ocular hypotelorism, however, not cyclopia. Based on this we propose that anophthalmia and cyclopia are both the strongest ophthalmologic finding, however, depending on the type of HPE underlying.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-09DOI: 10.1101/2024.08.07.607114
Takamoto Shima, Yuuki Kawabata, Yoshimasa Yagi
Dyro mutant is female sterile, and oogenesis is aborted during stage8-9 of oogenesis. We investigated detail of the oogenesis defect of Dyro mutant. At first, we confirmed loss of Dyro caused female sterility by genetic rescue experiment. Then, we performed genetic mosaic analysis and found Dyro expression in germ cell is important for oogenesis. In Dyro mutant, inhibition of programmed cell death suppressed cell death of germ cells during oogenesis but failed to rescue fertility. It indicates that abortion of oogenesis is not because of mis-regulation of cell death signal but there is oogenesis defect which activates Caspase signaling pathway. Then, we observed Dyro mutant and looking for defects which may trigger cell death of germ cells in Dyro mutant. We found oogenesis abortion timing is similar to yolk protein mutant but different from amino acid starvation. It suggests that nutrient signal defect does not triggers cell death in Dyro mutant. We carefully observed the defect of Dyro mutant ovaries and found abnormal morphology of nucleolus and chromosome in nurse cells. It seems chromosome in Dyro mutant is thick and nucleolus is limited in small space between thick chromosomes in Dyro mutant nurse cells. Other defect we found is aggregated protein accumulation in germ cells. These data suggest that Dyro has important role in mid-oogenesis stage germ cell and loss of Dyro causes defect in nuclear of nurse cells which may leads to abortion of oogenesis.
{"title":"Analysis of oogenesis defects in Dyro mutant of Drosophila melanogaster.","authors":"Takamoto Shima, Yuuki Kawabata, Yoshimasa Yagi","doi":"10.1101/2024.08.07.607114","DOIUrl":"https://doi.org/10.1101/2024.08.07.607114","url":null,"abstract":"<em>Dyro</em> mutant is female sterile, and oogenesis is aborted during stage8-9 of oogenesis. We investigated detail of the oogenesis defect of <em>Dyro</em> mutant. At first, we confirmed loss of Dyro caused female sterility by genetic rescue experiment. Then, we performed genetic mosaic analysis and found Dyro expression in germ cell is important for oogenesis. In <em>Dyro</em> mutant, inhibition of programmed cell death suppressed cell death of germ cells during oogenesis but failed to rescue fertility. It indicates that abortion of oogenesis is not because of mis-regulation of cell death signal but there is oogenesis defect which activates Caspase signaling pathway. Then, we observed <em>Dyro</em> mutant and looking for defects which may trigger cell death of germ cells in <em>Dyro</em> mutant. We found oogenesis abortion timing is similar to yolk protein mutant but different from amino acid starvation. It suggests that nutrient signal defect does not triggers cell death in <em>Dyro</em> mutant. We carefully observed the defect of <em>Dyro</em> mutant ovaries and found abnormal morphology of nucleolus and chromosome in nurse cells. It seems chromosome in <em>Dyro</em> mutant is thick and nucleolus is limited in small space between thick chromosomes in <em>Dyro</em> mutant nurse cells. Other defect we found is aggregated protein accumulation in germ cells. These data suggest that <em>Dyro</em> has important role in mid-oogenesis stage germ cell and loss of Dyro causes defect in nuclear of nurse cells which may leads to abortion of oogenesis.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1101/2024.08.07.606262
Bohou Wu, Jae Hyun Lee, Kara M. Foshay, Li Zhang, Croydon J. Fernandes, Boyang Gao, Xiaoyang Dou, Chris Z. Zhang, Guoping Fan, Becky X. Xiao, Bruce T. Lahn
Lineage restriction, the biological phenomenon whereby developing cells progressively lose fate potency for all but their adopted lineages, is foundational to multicellular lifeforms as it secures the functional identities of the myriad cell types in the body. The mechanisms of lineage restriction remain enigmatic. We previously defined occlusion as a mode of gene silencing wherein affected genes lack the transcriptional potency to be activated by their cognate transcription factors (TFs). Here, we present a comprehensive mechanistic basis of lineage restriction as driven by gene occlusion. Specifically, we show that genes can become occluded simply by the default action of chromatinization in the absence of TF binding, that naive pluripotent stem cells establish full developmental potency via their capacity to erase occlusion, that primed pluripotent cells shut down this deocclusion ability in preparation for differentiation, that differentiating cells become increasingly restricted in their fate potency by the irreversible occlusion of lineage-inappropriate genes, and that stem cells employ placeholder factors (PFs) to protect silent genes needed for later activation from premature occlusion. Collectively, these mechanisms drive lineage restriction whereby the transcriptionally potent portion of the genome shrinks progressively during differentiation, rendering the fate potency of developing cells to also dwindle progressively.
{"title":"Mechanistic basis of lineage restriction","authors":"Bohou Wu, Jae Hyun Lee, Kara M. Foshay, Li Zhang, Croydon J. Fernandes, Boyang Gao, Xiaoyang Dou, Chris Z. Zhang, Guoping Fan, Becky X. Xiao, Bruce T. Lahn","doi":"10.1101/2024.08.07.606262","DOIUrl":"https://doi.org/10.1101/2024.08.07.606262","url":null,"abstract":"Lineage restriction, the biological phenomenon whereby developing cells progressively lose fate potency for all but their adopted lineages, is foundational to multicellular lifeforms as it secures the functional identities of the myriad cell types in the body. The mechanisms of lineage restriction remain enigmatic. We previously defined occlusion as a mode of gene silencing wherein affected genes lack the transcriptional potency to be activated by their cognate transcription factors (TFs). Here, we present a comprehensive mechanistic basis of lineage restriction as driven by gene occlusion. Specifically, we show that genes can become occluded simply by the default action of chromatinization in the absence of TF binding, that naive pluripotent stem cells establish full developmental potency via their capacity to erase occlusion, that primed pluripotent cells shut down this deocclusion ability in preparation for differentiation, that differentiating cells become increasingly restricted in their fate potency by the irreversible occlusion of lineage-inappropriate genes, and that stem cells employ placeholder factors (PFs) to protect silent genes needed for later activation from premature occlusion. Collectively, these mechanisms drive lineage restriction whereby the transcriptionally potent portion of the genome shrinks progressively during differentiation, rendering the fate potency of developing cells to also dwindle progressively.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1101/2024.08.06.606905
Marcos Wappner, Koichiro Uriu, Andrew C. Oates, Luis G. Morelli
Notch signaling is a ubiquitous and versatile intercellular signaling system that drives collective behaviors and pattern formation in biological tissues. During embryonic development, Notch is involved in generation of collective biochemical oscillations that form the vertebrate body segments, and its failure results in embryonic defects. Notch ligands of the Delta family are key components of this collective rhythm, but it is unclear how different Delta ligands with distinct properties contribute to relaying information among cells. Motivated by the zebrafish segmentation clock, in this work we propose a theory describing interactions between biochemical oscillators, where Notch receptor is bound by both oscillatory and nonoscillatory Delta ligands. Based on previous in vitro binding studies, we first consider Notch activation by Delta dimers. This hypothesis is consistent with experimental observations in conditions of perturbed Notch signaling. Then we test an alternative hypothesis where Delta monomers directly bind and activate Notch, and show that this second model can also describe the experimental observations. We show that these two hypotheses assign different roles for a non-oscillatory ligand, as a binding partner or as a baseline signal. Finally, we discuss experiments to distinguish between the two scenarios. Broadly, this work highlights how a multiplicity of ligands may be harnessed by a signaling system to generate versatile responses.
{"title":"Multiple Notch ligands in the synchronization of the segmentation clock","authors":"Marcos Wappner, Koichiro Uriu, Andrew C. Oates, Luis G. Morelli","doi":"10.1101/2024.08.06.606905","DOIUrl":"https://doi.org/10.1101/2024.08.06.606905","url":null,"abstract":"Notch signaling is a ubiquitous and versatile intercellular signaling system that drives collective behaviors and pattern formation in biological tissues. During embryonic development, Notch is involved in generation of collective biochemical oscillations that form the vertebrate body segments, and its failure results in embryonic defects. Notch ligands of the Delta family are key components of this collective rhythm, but it is unclear how different Delta ligands with distinct properties contribute to relaying information among cells. Motivated by the zebrafish segmentation clock, in this work we propose a theory describing interactions between biochemical oscillators, where Notch receptor is bound by both oscillatory and nonoscillatory Delta ligands. Based on previous in vitro binding studies, we first consider Notch activation by Delta dimers. This hypothesis is consistent with experimental observations in conditions of perturbed Notch signaling. Then we test an alternative hypothesis where Delta monomers directly bind and activate Notch, and show that this second model can also describe the experimental observations. We show that these two hypotheses assign different roles for a non-oscillatory ligand, as a binding partner or as a baseline signal. Finally, we discuss experiments to distinguish between the two scenarios. Broadly, this work highlights how a multiplicity of ligands may be harnessed by a signaling system to generate versatile responses.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-08DOI: 10.1101/2024.08.08.607226
Samantha Bromley-Coolidge, Diego Iruegas, Bruce Appel
The extracellular matrix (ECM) provides critical biochemical and structural cues that regulate neural development. Chondroitin sulfate proteoglycans (CSPGs), a major ECM component, have been implicated in modulating oligodendrocyte precursor cell (OPC) proliferation, migration, and maturation, but their specific roles in oligodendrocyte lineage cell (OLC) development and myelination in vivo remain poorly understood. Here, we use zebrafish as a model system to investigate the spatiotemporal dynamics of ECM deposition and CSPG localization during central nervous system (CNS) development, with a focus on their relationship to OLCs. We demonstrate that ECM components, including CSPGs, are dynamically expressed in distinct spatiotemporal patterns coinciding with OLC development and myelination. We found that zebrafish lacking cspg4 function produced normal numbers of OLCs, which appeared to undergo proper differentiation. However, OPC morphology in mutant larvae was aberrant. Nevertheless, the number and length of myelin sheaths produced by mature oligodendrocytes were unaffected. These data indicate that Cspg4 regulates OPC morphogenesis in vivo, supporting the role of the ECM in neural development.
{"title":"Cspg4 sculpts oligodendrocyte precursor cell morphology","authors":"Samantha Bromley-Coolidge, Diego Iruegas, Bruce Appel","doi":"10.1101/2024.08.08.607226","DOIUrl":"https://doi.org/10.1101/2024.08.08.607226","url":null,"abstract":"The extracellular matrix (ECM) provides critical biochemical and structural cues that regulate neural development. Chondroitin sulfate proteoglycans (CSPGs), a major ECM component, have been implicated in modulating oligodendrocyte precursor cell (OPC) proliferation, migration, and maturation, but their specific roles in oligodendrocyte lineage cell (OLC) development and myelination in vivo remain poorly understood. Here, we use zebrafish as a model system to investigate the spatiotemporal dynamics of ECM deposition and CSPG localization during central nervous system (CNS) development, with a focus on their relationship to OLCs. We demonstrate that ECM components, including CSPGs, are dynamically expressed in distinct spatiotemporal patterns coinciding with OLC development and myelination. We found that zebrafish lacking cspg4 function produced normal numbers of OLCs, which appeared to undergo proper differentiation. However, OPC morphology in mutant larvae was aberrant. Nevertheless, the number and length of myelin sheaths produced by mature oligodendrocytes were unaffected. These data indicate that Cspg4 regulates OPC morphogenesis in vivo, supporting the role of the ECM in neural development.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1101/2024.08.07.606990
Janine Hoffmann, Theresa M. Schütze, Annika Kolodziejczyk, Annekathrin Kränkel, Susanne Reinhardt, Razvan P. Derihaci, Cahit Birdir, Pauline Wimberger, Haruhiko Koseki, Mareike Albert
Neocortex development is characterized by sequential phases of neural progenitor cell (NPC) expansion, neurogenesis and gliogenesis. Polycomb-mediated epigenetic mechanisms are known to play important roles in regulating the lineage potential of NPCs during development. The composition of Polycomb Repressive Complex 1 (PRC1) is highly diverse in mammals and was hypothesized to contribute to context-specific regulation of cell fate. Here, we have performed side-by-side comparison of the role of canonical PRC1.2/1.4 and non-canonical PRC1.3/1.5, all of which are expressed in the developing neocortex, in NSC proliferation and differentiation. We found that the deletion of Pcgf2/4 in NSCs led to a strong reduction in proliferation and to altered lineage fate, both during the neurogenic and gliogenic phase, whereas Pcgf3/5 played a minor role. Mechanistically, genes encoding stem cell and neurogenic factors were bound by PRC1 and differentially expressed upon Pcgf2/4 deletion. Thus, rather than different PRC1 sub-complexes contributing to different phases of neural development, we found that canonical PRC1 played a more significant role in NSC regulation during proliferative, neurogenic and gliogenic phases compared to non-canonical PRC1.
{"title":"Canonical and non-canonical PRC1 differentially contribute to the regulation of neural stem cell fate","authors":"Janine Hoffmann, Theresa M. Schütze, Annika Kolodziejczyk, Annekathrin Kränkel, Susanne Reinhardt, Razvan P. Derihaci, Cahit Birdir, Pauline Wimberger, Haruhiko Koseki, Mareike Albert","doi":"10.1101/2024.08.07.606990","DOIUrl":"https://doi.org/10.1101/2024.08.07.606990","url":null,"abstract":"Neocortex development is characterized by sequential phases of neural progenitor cell (NPC) expansion, neurogenesis and gliogenesis. Polycomb-mediated epigenetic mechanisms are known to play important roles in regulating the lineage potential of NPCs during development. The composition of Polycomb Repressive Complex 1 (PRC1) is highly diverse in mammals and was hypothesized to contribute to context-specific regulation of cell fate. Here, we have performed side-by-side comparison of the role of canonical PRC1.2/1.4 and non-canonical PRC1.3/1.5, all of which are expressed in the developing neocortex, in NSC proliferation and differentiation. We found that the deletion of <em>Pcgf2/4</em> in NSCs led to a strong reduction in proliferation and to altered lineage fate, both during the neurogenic and gliogenic phase, whereas <em>Pcgf3/5</em> played a minor role. Mechanistically, genes encoding stem cell and neurogenic factors were bound by PRC1 and differentially expressed upon <em>Pcgf2/4</em> deletion. Thus, rather than different PRC1 sub-complexes contributing to different phases of neural development, we found that canonical PRC1 played a more significant role in NSC regulation during proliferative, neurogenic and gliogenic phases compared to non-canonical PRC1.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1101/2024.08.05.606556
Shiyu Sun, Yi Zheng, Yung Su Kim, Zheng Zhong, Norio Kobayashi, Xufeng Xue, Yue Liu, Zhuowei Zhou, Yanhong Xu, Jinglei Zhai, Hongmei Wang, Jianping Fu
The ultimate outcome of the gastrulation in mammalian development is a recognizable trilaminar disc structure containing organized cell lineages with spatially defined identities in an emerging coordinate system1–4. Despite its importance in human development, gastrulation remains difficult to study. Stem cell-based embryo models, including those that recapitulate different aspects of pre- and peri-gastrulation human development5–15, are emerging as promising tools for studying human embryogenesis16–18. However, it remains unclear whether existing human embryo models are capable of modeling the development of the trilaminar embryonic disc structure, a hallmark of human gastrulation. Here we report a transgene-free human embryo model derived solely from primed human pluripotent stem cells (hPSCs), which recapitulates various aspects of peri-gastrulation human development, including formation of trilaminar embryonic layers situated between dorsal amnion and ventral definitive yolk sac and primary hematopoiesis. We term this model the peri-gastrulation trilaminar embryonic disc (PTED) embryoid. The development of PTED embryoid does not follow natural developmental sequences of cell lineage diversification or spatial organization. Instead, it exploits both extrinsic control of tissue boundaries and intrinsic self-organizing properties and embryonic plasticity of the diverse peri-gastrulation-stage cell lineages, leading to the emergence of in vivo-like tissue organization and function at a global scale. Our lineage tracing study reveals that in PTED embryoids, embryonic and extraembryonic mesoderm cells, as well as embryonic and extraembryonic endoderm cells, share common progenitors emerging during peri-gastrulation development. Active hematopoiesis and blood cell generation are evident in the yolk sac-like structure of PTED embryoids. Together, PTED embryoids provide a promising and ethically less challenging model for studying self-organizing properties of peri-gastrulation human development.
{"title":"A transgene-free, human peri-gastrulation embryo model with trilaminar embryonic disc-, amnion- and yolk sac-like structures","authors":"Shiyu Sun, Yi Zheng, Yung Su Kim, Zheng Zhong, Norio Kobayashi, Xufeng Xue, Yue Liu, Zhuowei Zhou, Yanhong Xu, Jinglei Zhai, Hongmei Wang, Jianping Fu","doi":"10.1101/2024.08.05.606556","DOIUrl":"https://doi.org/10.1101/2024.08.05.606556","url":null,"abstract":"The ultimate outcome of the gastrulation in mammalian development is a recognizable trilaminar disc structure containing organized cell lineages with spatially defined identities in an emerging coordinate system<sup>1–4</sup>. Despite its importance in human development, gastrulation remains difficult to study. Stem cell-based embryo models, including those that recapitulate different aspects of pre- and peri-gastrulation human development<sup>5–15</sup>, are emerging as promising tools for studying human embryogenesis<sup>16–18</sup>. However, it remains unclear whether existing human embryo models are capable of modeling the development of the trilaminar embryonic disc structure, a hallmark of human gastrulation. Here we report a transgene-free human embryo model derived solely from primed human pluripotent stem cells (hPSCs), which recapitulates various aspects of peri-gastrulation human development, including formation of trilaminar embryonic layers situated between dorsal amnion and ventral definitive yolk sac and primary hematopoiesis. We term this model the peri-gastrulation trilaminar embryonic disc (PTED) embryoid. The development of PTED embryoid does not follow natural developmental sequences of cell lineage diversification or spatial organization. Instead, it exploits both extrinsic control of tissue boundaries and intrinsic self-organizing properties and embryonic plasticity of the diverse peri-gastrulation-stage cell lineages, leading to the emergence of <em>in vivo</em>-like tissue organization and function at a global scale. Our lineage tracing study reveals that in PTED embryoids, embryonic and extraembryonic mesoderm cells, as well as embryonic and extraembryonic endoderm cells, share common progenitors emerging during peri-gastrulation development. Active hematopoiesis and blood cell generation are evident in the yolk sac-like structure of PTED embryoids. Together, PTED embryoids provide a promising and ethically less challenging model for studying self-organizing properties of peri-gastrulation human development.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-07DOI: 10.1101/2024.08.02.606315
Yuchen Wen, Hang He, Yunxi Ma, Lorie Chen Cai, Huaquan Wang, Yanmei Li, Baobing Zhao, Zhigang Cai
Cell plasticity (CP), describing a dynamic cell state, plays a crucial role in maintaining homeostasis during organ morphogenesis, regeneration and damage-to-repair biological process. Single-cell-omics datasets provide unprecedented resource to empowers analysis on CP. Hematopoiesis offers fertile opportunities to develop quantitative methods for understanding CP with rich supports from experimental ground-truths. In this study we generated high-quality lineage-negative (Lin−) single-cell RNA-sequencing datasets under various conditions and introduced a working pipeline named Snapdragon to interrogate naïve and disturbed plasticity of hematopoietic stem and progenitor cells (HSPCs) with mutational or environmental challenges. Utilizing embedding methods UMAP or FA, a continuum of hematopoietic development is visually observed in wildtype where the pipeline confirms a very low Proportion of hybrid-cells (Phc, with bias range: 0.4-0.6) on a transition trajectory. Upon Tet2 mutation, a driver of leukemia, or treatment of DSS, an inducer of colitis, Phc is increased and plasticity of HSPCs was enhanced. Quantitative analysis indicates that Tet2 mutation enhances HSC self-renewal capability while DSS treatment results in an enhanced myeloid-skewing trajectory, suggesting their similar but different consequences. We prioritized several transcription factors (i.e the EGR family) and signaling pathways (i.e. receptors IL1R1 and ADRB, inflammation and sympathy-sensing respectively) which are responsible for Phc alterations. CellOracle-based simulation suggests that knocking-out EGR regulons or pathways of IL1R1 and ADRB partially reverses Phc promoted by Tet2 mutation and inflammation. In conclusion, the study provides high-quality datasets with single-cell transcriptomic matrices for diversified hematopoietic simulations and a computational pipeline Snapdragon for quantifying disturbed Phc and CP. (247 words)
{"title":"Computing hematopoietic stem and progenitor cell plasticity in response to genetic mutations and environmental stimulations","authors":"Yuchen Wen, Hang He, Yunxi Ma, Lorie Chen Cai, Huaquan Wang, Yanmei Li, Baobing Zhao, Zhigang Cai","doi":"10.1101/2024.08.02.606315","DOIUrl":"https://doi.org/10.1101/2024.08.02.606315","url":null,"abstract":"Cell plasticity (CP), describing a dynamic cell state, plays a crucial role in maintaining homeostasis during organ morphogenesis, regeneration and damage-to-repair biological process. Single-cell-omics datasets provide unprecedented resource to empowers analysis on CP. Hematopoiesis offers fertile opportunities to develop quantitative methods for understanding CP with rich supports from experimental ground-truths. In this study we generated high-quality lineage-negative (Lin<sup>−</sup>) single-cell RNA-sequencing datasets under various conditions and introduced a working pipeline named Snapdragon to interrogate naïve and disturbed plasticity of hematopoietic stem and progenitor cells (HSPCs) with mutational or environmental challenges. Utilizing embedding methods UMAP or FA, a continuum of hematopoietic development is visually observed in wildtype where the pipeline confirms a very low Proportion of hybrid-cells (<em>P<sub>hc</sub></em>, with bias range: 0.4-0.6) on a transition trajectory. Upon <em>Tet2</em> mutation, a driver of leukemia, or treatment of DSS, an inducer of colitis, <em>P<sub>hc</sub></em> is increased and plasticity of HSPCs was enhanced. Quantitative analysis indicates that <em>Tet2</em> mutation enhances HSC self-renewal capability while DSS treatment results in an enhanced myeloid-skewing trajectory, suggesting their similar but different consequences. We prioritized several transcription factors (i.e the EGR family) and signaling pathways (i.e. receptors IL1R1 and ADRB, inflammation and sympathy-sensing respectively) which are responsible for <em>P<sub>hc</sub></em> alterations. CellOracle-based simulation suggests that knocking-out EGR regulons or pathways of IL1R1 and ADRB partially reverses <em>P<sub>hc</sub></em> promoted by <em>Tet2</em> mutation and inflammation. In conclusion, the study provides high-quality datasets with single-cell transcriptomic matrices for diversified hematopoietic simulations and a computational pipeline Snapdragon for quantifying disturbed <em>P<sub>hc</sub></em> and CP. (247 words)","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141943815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-06DOI: 10.1101/2024.08.01.606240
Andrew Olander, Cynthia M Ramirez, Veronica Haro Acosta, Paloma Medina, Sara Kaushik, Vanessa D Jonsson, Shaheen S Sikandar
Aging increases breast cancer risk while an early first pregnancy reduces a woman’s life-long risk. Several studies have explored the effect of either aging or pregnancy on mammary epithelial cells (MECs), but the combined effect of both remains unclear. Here, we interrogate the functional and transcriptomic changes at single cell resolution in the mammary gland of aged nulliparous and parous mice to discover that pregnancy normalizes age-related imbalances in lineage composition, while also inducing a differentiated cell state. Importantly, we uncover a minority population of Il33-expressing hybrid MECs with high cellular potency that accumulate in aged nulliparous mice but is significantly reduced in aged parous mice. Functionally, IL33 treatment of basal, but not luminal, epithelial cells from young mice phenocopies aged nulliparous MECs and promotes formation of organoids with Trp53 knockdown. Collectively, our study demonstrates that pregnancy blocks the age-associated loss of lineage integrity in the basal layer through a decrease in Il33+ hybrid MECs, potentially contributing to pregnancy-induced breast cancer protection.
{"title":"Pregnancy Reduces Il33+ Hybrid Progenitor Accumulation in the Aged Mammary Gland","authors":"Andrew Olander, Cynthia M Ramirez, Veronica Haro Acosta, Paloma Medina, Sara Kaushik, Vanessa D Jonsson, Shaheen S Sikandar","doi":"10.1101/2024.08.01.606240","DOIUrl":"https://doi.org/10.1101/2024.08.01.606240","url":null,"abstract":"Aging increases breast cancer risk while an early first pregnancy reduces a woman’s life-long risk. Several studies have explored the effect of either aging or pregnancy on mammary epithelial cells (MECs), but the combined effect of both remains unclear. Here, we interrogate the functional and transcriptomic changes at single cell resolution in the mammary gland of aged nulliparous and parous mice to discover that pregnancy normalizes age-related imbalances in lineage composition, while also inducing a differentiated cell state. Importantly, we uncover a minority population of <em>Il33</em>-expressing hybrid MECs with high cellular potency that accumulate in aged nulliparous mice but is significantly reduced in aged parous mice. Functionally, IL33 treatment of basal, but not luminal, epithelial cells from young mice phenocopies aged nulliparous MECs and promotes formation of organoids with <em>Trp53</em> knockdown. Collectively, our study demonstrates that pregnancy blocks the age-associated loss of lineage integrity in the basal layer through a decrease in <em>Il33+</em> hybrid MECs, potentially contributing to pregnancy-induced breast cancer protection.","PeriodicalId":501269,"journal":{"name":"bioRxiv - Developmental Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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