3D reconstruction of a gastrulating human embryo.

Progress in understanding early human development has been impeded by the scarcity of reference datasets from natural embryos, particularly those with spatial information during crucial stages like gastrulation. We conducted high-resolution spatial transcriptomics profiling on 38,562 spots from 62 transverse sections of an intact Carnegie stage (CS) 8 human embryo. From this spatial transcriptomic dataset, we constructed a 3D model of the CS8 embryo, in which a range of cell subtypes are identified, based on gene expression patterns and positional register, along the anterior-posterior, medial-lateral, and dorsal-ventral axis in the embryo. We further characterized the lineage trajectories of embryonic and extra-embryonic tissues and associated regulons and the regionalization of signaling centers and signaling activities that underpin lineage progression and tissue patterning during gastrulation. Collectively, the findings of this study provide insights into gastrulation and post-gastrulation development of the human embryo.

Ex utero monkey embryogenesis from blastocyst to early organogenesis.

The third and fourth weeks of gestation in primates are marked by several developmental milestones, including gastrulation and the formation of organ primordia. However, our understanding of this period is limited due to restricted access to in vivo embryos. To address this gap, we developed an embedded 3D culture system that allows for the extended ex utero culture of cynomolgus monkey embryos for up to 25 days post-fertilization. Morphological, histological, and single-cell RNA-sequencing analyses demonstrate that ex utero cultured monkey embryos largely recapitulated key events of in vivo development. With this platform, we were able to delineate lineage trajectories and genetic programs involved in neural induction, lateral plate mesoderm differentiation, yolk sac hematopoiesis, primitive gut, and primordial germ-cell-like cell development in monkeys. Our embedded 3D culture system provides a robust and reproducible platform for growing monkey embryos from blastocysts to early organogenesis and studying primate embryogenesis ex utero.

Dissecting embryonic and extraembryonic lineage crosstalk with stem cell co-culture.

Embryogenesis necessitates harmonious coordination between embryonic and extraembryonic tissues. Although stem cells of both embryonic and extraembryonic origins have been generated, they are grown in different culture conditions. In this study, utilizing a unified culture condition that activates the FGF, TGF-ß, and WNT pathways, we have successfully derived embryonic stem cells (FTW-ESCs), extraembryonic endoderm stem cells (FTW-XENs), and trophoblast stem cells (FTW-TSCs) from the three foundational tissues of mouse and cynomolgus monkey (Macaca fascicularis) blastocysts. This approach facilitates the co-culture of embryonic and extraembryonic stem cells, revealing a growth inhibition effect exerted by extraembryonic endoderm cells on pluripotent cells, partially through extracellular matrix signaling. Additionally, our cross-species analysis identified both shared and unique transcription factors and pathways regulating FTW-XENs. The embryonic and extraembryonic stem cell co-culture strategy offers promising avenues for developing more faithful embryo models and devising more developmentally pertinent differentiation protocols.

Generation of Blastocyst-like Structures from Mouse Embryonic and Adult Cell Cultures.

A single mouse blastomere from an embryo until the 8-cell stage can generate an entire blastocyst. Whether laboratory-cultured cells retain a similar generative capacity remains unknown. Starting from a single stem cell type, extended pluripotent stem (EPS) cells, we established a 3D differentiation system that enabled the generation of blastocyst-like structures (EPS-blastoids) through lineage segregation and self-organization. EPS-blastoids resembled blastocysts in morphology and cell-lineage allocation and recapitulated key morphogenetic events during preimplantation and early postimplantation development in vitro. Upon transfer, some EPS-blastoids underwent implantation, induced decidualization, and generated live, albeit disorganized, tissues in utero. Single-cell and bulk RNA-sequencing analysis revealed that EPS-blastoids contained all three blastocyst cell lineages and shared transcriptional similarity with natural blastocysts. We also provide proof of concept that EPS-blastoids can be generated from adult cells via cellular reprogramming. EPS-blastoids provide a unique platform for studying early embryogenesis and pave the way to creating viable synthetic embryos by using cultured cells.

Blastocyst-like structures generated from human pluripotent stem cells.

Limited access to embryos has hampered the study of human embryogenesis and disorders that occur during early pregnancy. Human pluripotent stem cells provide an alternative means to study human development in a dish1-7. Recent advances in partial embryo models derived from human pluripotent stem cells have enabled human development to be examined at early post-implantation stages8-14. However, models of the pre-implantation human blastocyst are lacking. Starting from naive human pluripotent stem cells, here we developed an effective three-dimensional culture strategy with successive lineage differentiation and self-organization to generate blastocyst-like structures in vitro. These structures-which we term 'human blastoids'-resemble human blastocysts in terms of their morphology, size, cell number, and composition and allocation of different cell lineages. Single-cell RNA-sequencing analyses also reveal the transcriptomic similarity of blastoids to blastocysts. Human blastoids are amenable to embryonic and extra-embryonic stem cell derivation and can further develop into peri-implantation embryo-like structures in vitro. Using chemical perturbations, we show that specific isozymes of protein kinase C have a critical function in the formation of the blastoid cavity. Human blastoids provide a readily accessible, scalable, versatile and perturbable alternative to blastocysts for studying early human development, understanding early pregnancy loss and gaining insights into early developmental defects.

Cell competition constitutes a barrier for interspecies chimerism.

Cell competition involves a conserved fitness-sensing process during which fitter cells eliminate neighbouring less-fit but viable cells1. Cell competition has been proposed as a surveillance mechanism to ensure normal development and tissue homeostasis, and has also been suggested to act as a barrier to interspecies chimerism2. However, cell competition has not been studied in an interspecies context during early development owing to the lack of an in vitro model. Here we developed an interspecies pluripotent stem cell (PSC) co-culture strategy and uncovered a previously unknown mode of cell competition between species. Interspecies competition between PSCs occurred in primed but not naive pluripotent cells, and between evolutionarily distant species. By comparative transcriptome analysis, we found that genes related to the NF-κB signalling pathway, among others, were upregulated in less-fit 'loser' human cells. Genetic inactivation of a core component (P65, also known as RELA) and an upstream regulator (MYD88) of the NF-κB complex in human cells could overcome the competition between human and mouse PSCs, thereby improving the survival and chimerism of human cells in early mouse embryos. These insights into cell competition pave the way for the study of evolutionarily conserved mechanisms that underlie competitive cell interactions during early mammalian development. Suppression of interspecies PSC competition may facilitate the generation of human tissues in animals.

Lymphocyte-to-C-Reactive Protein Ratio as an Early Sepsis Biomarker for Neonates with Suspected Sepsis.

Background: Neonatal sepsis is an extremely dangerous and fatal disease among neonates, and its timely diagnosis is critical to treatment. This research is aimed at evaluating the clinical significance of the lymphocyte-to-C-reactive protein ratio (LCR) as an early sepsis indicator in neonates with suspected sepsis. Methods: Between January 2016 and December 2021, 1269 neonates suspected of developing sepsis were included in this research. Among them, sepsis was diagnosed in 819 neonates, with 448 severe cases, as per the International Pediatric Sepsis Consensus. Data related to clinical and laboratory tests were obtained via electronic medical records. LCR was calculated as total lymphocyte (109 cells/L)/C-reactive protein (mg/L). Multivariate logistic regression analysis was employed to evaluate the effectiveness of LCR as an independent indicator for determining sepsis in susceptible sepsis neonates. Receiver operating characteristic (ROC) curve analysis was conducted for investigating the diagnostic significance of LCR in sepsis. When suitable, the statistical tool SPSS 24.0 was used for statistical analyses. Results: LCR decreased significantly in the control, mild, and severe sepsis groups. Further analyses exhibited that there was a substantially greater incidence of sepsis in neonates in the low-LCR group (LCR ≤ 3.94) as opposed to the higher LCR group (LCR > 3.94) (77.6% vs. 51.4%, p < 0.001). Correlation analysis indicated a substantial negative association of LCR with procalcitonin (r = -0.519, p < 0.001) and hospital stay duration (r = -0.258, p < 0.001). Multiple logistic regression analysis depicted LCR as an independent indicator for identifying sepsis and severe cases of this disease. ROC curve analysis indicated the optimal cutoff value of LCR in identifying sepsis to be 2.10, with 88% sensitivity and 55% specificity. Conclusions: LCR has proven to be a potentially strong biomarker capable of identifying sepsis in a timely manner in neonates suspected to have the disease.

[Risk Factor Analysis of Abdominal Aortic Enlargement after Thoracic Endovascular Aortic Repair Using Two-Stent Graft Implantation for Stanford Type B Aortic Dissection].

Objective: To explore the risk factors of abdominal aortic enlargement (AAE) after thoracic endovascular aortic repair using two-stent graft implantation (TEVAR-TSI) for Stanford type B aortic dissection. Methods: The clinical and imaging data of patients who underwent TEVAR-TSI for Stanford type B aortic dissection in the First Affiliated Hospital of Hebei North University from January 2013 through September 2020 were retrospectively collected and analyzed. CT angiography (CTA) scans were performed before the procedure. Follow-up CTA scans were scheduled and performed in 1, 3, 6, and 12 months after the procedure and annually thereafter. The primary outcome was AAE. The risk factors of AAE after TEVAR-TSI were selected and survival analysis and multivariate logistic regression were conducted accordingly. Results: A total of 146 patients were regularly followed up at our hospital, with the median followup time of the entire cohort being 48 months (ranging from 12 to 84 months). During the followup period after TEVAR-TSI, the incidence of AAE was 19.9% (29/146). A total of 29 patients developed AAE (the AAE group), while 117 patients did not develop AAE (the non-AAE group). There were a total of 27 deaths, including 13 in the non-AAE group versus 14 in the AAE group. Distal aortic reoperation was performed on 10 patients, including 4 in the non-AAE group versus 6 in the AAE group. The cumulative long-term survival and freedom from distal aortic reoperation of the non-AAE group were both significantly better those of the AAE group ( P<0.05). Logistic multivariate regression analysis showed that independent risk factors of AAE after TEVAR-TSI included the following, partial thrombosis of the false lumen (odds ratio [ OR]=4.090, 95% confidence interval [ CI]: 1.539-10.867, P=0.005), the longer cumulative diameter of residual intimal tear above the level of the lowest renal arteries ( OR=1.290, 95% CI: 1.164-1.429, P=0.000), and shorter cumulative diameter of residual intimal tear below the level of the lowest renal arteries ( OR=0.487, 95% CI: 0.270-0.878, P=0.017). Conclusion: The prognosis of patients who developed AAE after TEVAR-TSI was not good. During followup visits, as precautions against the development of AAE, close attention should be paid to partial thrombosis of the false lumen, cumulative diameter of residual intimal tear above the level of the lowest renal arteries, and cumulative diameter of residual intimal tear below the level of the lowest renal arteries.

[The Characteristics of Aortic Remodeling after Thoracic Endovascular Aortic Repair using Two-stent Graft Implantation for Stanford Type B Aortic Dissection].

OBJECTIVE: To investigate the characteristics of aortic remodeling after thoracic endovascular aortic repair using two-stent graft implantation (TEVAR-TSI) for Stanford B aortic dissection. METHODS: The clinical and imaging data of 128 patients who underwent TEVAR-TSI for Stanford B aortic dissection in the First Affiliated Hospital of Hebei North University from January 2013 through May 2019 were retrospectively collected. CT images were obtained before (T 0) TEVAR-TSI and, 1 week (T 1), 3 months (T 2), 6 months (T 3), 1 year (T 4) after TEVAR-TSI. The maximum diameter of the true lumen and false lumen in the short axis view was accessed at five levels: L 1: the level of primary tear entry, L 2: the level of the bronchial bifurcation, L 3: the level of the distal of the first stent-graft, L 4: the level of the celiac trunk, L 5: the level of the lowest renal arteries. The false lumen thrombosis in the thoracic aorta and abdominal aorta were assessed at different times, the false lumen and true lumen changes in diameter were evaluated between the preoperative and postoperative CT scan. RESULTS: The stented segment of the descending thoracic aorta was evaluated (L 1-L 3): The true lumen diameter showed an increasing trend and the false lumen diameter showed an decreasing trend at levels L 1, L 2, and L 3, the change of true lumen diameter was positively correlated with the follow-up time ( r=0.721, 0.827, 0.893, P<0.05), and the change rate of true lumen diameter was positively correlated with the follow-up time ( r=0.763, 0.818, 0.902, P<0.05), and the change of false lumen diameter was negatively correlated with the follow-up time ( r=-0.750, -0.927, -0.934, P<0.05), and the change rate of false lumen diameter was negatively correlated with the follow-up time (-0.774, -0.935, -0.952, P<0.05). When the unstented segment of the abdominal aorta was evaluated (L 4-L 5), the average true lumen diameter at the level of celiac trunk increased significantly at 1 year by 13.7% ( P=0.007), however, the average false lumen diameter did not change over time ( P=0.406). The average true lumen diameter and false lumen diameter at the level of the lowest renal arteries increased over time as well, the average true lumen increased by 10.1%, and the average false lumen increased by 13.6% ( P=0.048, 0.017). Besides, the complete false lumen thrombosis rate of the stented segment of the descending thoracic aorta was higher than that of the unstented segment of the abdominal aorta.e complete false lumen thrombosis rate of the stented segment of the descending thoracic aorta was higher than that of the unstented segment of the abdominal aorta. CONCLUSION: After receiving TEVAR-TSI, Stanford type B aortic dissection patients had high thrombosis absorption rate in the thoracic aortic segment covered by stent, and the aortic remodeling was more ideal. The aortic remodeling effect in the abdominal aortic segment not covered was not ideal, and the inner diameter of the abdominal aorta tended to increase. Therefore, close follow-up monitoring should be conducted.

Long non-coding RNA NEAT1 promotes bone metastasis of prostate cancer through N6-methyladenosine.

BACKGROUND: N6-methyladenosine (m6A) is the most prevalent messenger RNA modification in mammalian cells. However, the disease relevant function of m6A on specific oncogenic long non-coding RNAs (ncRNAs) is not well understood. METHODS: We analyzed the m6A status using patients samples and bone metastatic PDXs. Through m6A high-throughput sequencing, we identified the m6A sites on NEAT1-1 in prostate bone metastatic PDXs. Mass spec assay showed interaction among NEAT1-1, CYCLINL1 and CDK19. RNA EMSA, RNA pull-down, mutagenesis, CLIP, western blot, ChIP and ChIRP assays were used to investigate the molecular mechanisms underlying the functions of m6A on NEAT1-1. Loss-of function and rescued experiments were executed to detect the biological roles of m6A on NEAT1-1 in the PDX cell phenotypes in vivo. RESULTS: In this study, we identified 4 credible m6A sites on long ncRNA NEAT1-1. High m6A level of NEAT1-1 was related to bone metastasis of prostate cancer and m6A level of NEAT1-1 was a powerful predictor of eventual death. Transcribed NEAT1-1 served as a bridge to facility the binding between CYCLINL1 and CDK19 and promoted the Pol II ser2 phosphorylation. Importantly, depletion of NEAT1-1or decreased m6A of NEAT1-1 impaired Pol II Ser-2p level in the promoter of RUNX2. Overexpression of NEAT1-1 induced cancer cell metastasis to lung and bone; xenograft growth and shortened the survival of mice, but NEAT1-1 with m6A site mutation failed to do these. CONCLUSION: Collectively, the findings indicate that m6A on ncRNA NEAT1-1 takes critical role in regulating Pol II ser2 phosphorylation and may be novel specific target for bone metastasis cancer therapy and diagnosis. New complex CYCLINL1/CDK19/NEAT1-1 might provide new insight into the potential mechanism of the pathogenesis and development of bone metastatic prostate cancer.

Glutamate receptor, ionotropic, N-methyl D-aspartate-associated protein 1, a potential target of miR-296, facilitates proliferation and migration of rectal cancer cells.

The purpose of our article was to probe the influence of GRINA on rectal cancer and how GRINA is regulated in rectal cancer. Based on the public data, we found that GRINA was highly expressed in rectal cancer tissues and related to worse prognosis in rectal cancer patients. MiR-296 was predicted as an upstream regulatory miRNA of GRINA, which was further verified by dual-luciferase reporter assay. Moreover, we revealed that up-regulation/down-regulation of GRINA facilitated/suppressed SW1463/SW837 cell proliferation, migration, and invasion. Rescue assays indicated that the facilitating impact of GRINA on SW1463 cell proliferation and motility was abolished by miR-296 over-expression whilst the suppressing influence of GRINA on SW837 cell proliferation, migration, and invasion was reversed by miR-296 depletion. These consequences indicated that GRINA, which might be regulated by miR-296, acted stimulative important impact on rectal cancer cells, insinuating that GRINA might be a novel potential target for rectal cancer therapy.

Pip-HoGu: An Artificial Assembly with Cooperative DNA Recognition Capable of Mimicking Transcription Factor Pairs.

Cooperation between pairs of transcription factors (TFs) has been widely demonstrated to play a pivotal role in the spatiotemporal regulation of gene expression, but blocking cooperative TF pair-DNA interactions synergistically has been challenging. To achieve this, we designed programmable DNA binder pyrrole-imidazole polyamides conjugated to host-guest assemblies (Pip-HoGu) to mimic the cooperation between natural TF pairs. By incorporating cyclodextrin (Cyd)-adamantane (Ada), we synthesized Ada1 (PIP1-Ada) and Cyd1 (PIP2-Cyd), which were evaluated using Tm, EMSA, competitive, and SPR assays and molecular dynamics studies. The results consistently demonstrated that Pip-HoGu system formed stable noncovalent cooperative complexes, thereby meeting key criteria for mimicking a TF pair. The system also had a longer recognition sequence (two-PIP binding length plus gap distance), favorable sequence selectivity, higher binding affinity, and in particular, a flexible gap distance (0-5 bp). For example, Ada1-Cyd1 showed thermal stability of 7.2 °C and a minimum free energy of interaction of -2.32 kcal·mol-1 with a targeting length of 14 bp. Furthermore, cell-based evaluation validated the capability of Pip-HoGu to exhibit potent cooperative inhibitory effects on gene expression under physiological conditions by disrupting TF pair-DNA function. In conclusion, the modular design of Pip-HoGu defines a general framework for mimicking naturally occurring cooperative TF pair-DNA interactions that offers a promising strategy for applications in the precise manipulation of cell fate.

Direct Observation of H3-H4 Octasome by High-Speed AFM.

Despite evidence that histone H3 and H4 proteins may act as the precursor for orientating the DNA sequence to form nucleosome structures, there is no direct evidence of the formed compact structure. Here, it is demonstrated that a histone H3-H4 octasome could be constructed without the involvement of histone H2A-H2B under in vitro reconstitution conditions. Atomic force microscopy was used to obtain the first direct observation of the octasome structure, which exhibited a similar core-protein size as that of a nucleosome but with a shorter core histone-binding DNA region. The octasome also displayed a one-step histone-dissociation pattern under heat treatment, distinct micrococcal nuclease and peplomycin accessibility, which suggests a different wrapping pattern to that in nucleosomes.

Generation of Human Blastoids from Naive Pluripotent Stem Cells.

Under certain culture conditions, naive human pluripotent stem cells can generate human blastocyst-like structures (called human blastoids). Human blastoids serve as an accessible model for human blastocysts and are amenable for large-scale production. Here, we describe a detailed step-by-step protocol for the robust and high-efficient generation of human blastoids from naive human pluripotent stem cells.

An inappropriate decline in ribosome levels drives a diverse set of neurodevelopmental disorders.

Many neurodevelopmental defects are linked to perturbations in genes involved in housekeeping functions, such as those encoding ribosome biogenesis factors. However, how reductions in ribosome biogenesis can result in tissue and developmental specific defects remains a mystery. Here we describe new allelic variants in the ribosome biogenesis factor AIRIM primarily associated with neurodevelopmental disorders. Using human cerebral organoids in combination with proteomic analysis, single-cell transcriptome analysis across multiple developmental stages, and single organoid translatome analysis, we identify a previously unappreciated mechanism linking changes in ribosome levels and the timing of cell fate specification during early brain development. We find ribosome levels decrease during neuroepithelial differentiation, making differentiating cells particularly vulnerable to perturbations in ribosome biogenesis during this time. Reduced ribosome availability more profoundly impacts the translation of specific transcripts, disrupting both survival and cell fate commitment of transitioning neuroepithelia. Enhancing mTOR activity by both genetic and pharmacologic approaches ameliorates the growth and developmental defects associated with intellectual disability linked variants, identifying potential treatment options for specific brain ribosomopathies. This work reveals the cellular and molecular origins of protein synthesis defect-related disorders of human brain development. Highlights: AIRIM variants reduce ribosome levels specifically in neural progenitor cells. Inappropriately low ribosome levels cause a transient delay in radial glia fate commitment.Reduced ribosome levels impair translation of a selected subset of mRNAs.Genetic and pharmacologic activation of mTORC1 suppresses AIRIM-linked phenotypes.

Enhancer RNA promotes resistance to radiotherapy in bone-metastatic prostate cancer by m6A modification.

Rationale: Prostate cancer metastasizes to the bone with the highest frequency and exhibits high resistance to 177Lu-prostate-specific membrane antigen (PSMA) radioligand therapy. Little is known about bone metastatic prostate cancer (mPCa) resistance to radiation. Methods: We filtered the metastatic eRNA using RNA-seq, MeRIP-seq, RT-qPCR and bioinformation. Western blot, RT-qPCR, CLIP, co-IP and RNA pull-down assays were used for RNA/protein interaction, RNA or protein expression examination. MTS assay was used to determine cell viability in vitro, xenograft assay was used to examine the tumor growth in mice. Results: In this study, we screened and identified bone-specific N6 adenosine methylation (m6A) on enhancer RNA (eRNA) that played a post-transcriptional functional role in bone mPCa and was correlated with radiotherapy (RT) resistance. Further data demonstrated that RNA-binding protein KHSRP recognized both m6A at eRNA and m6Am at 5'-UTR of mRNA to block RNA degradation from exoribonuclease XRN2. Depletion of the MLXIPe/KHSRP/PSMD9 regulatory complex inhibited tumor growth and RT sensitization of bone mPCa xenograft in vitro and in vivo. Conclusions: Our findings indicate that a bone-specific m6A-modified eRNA plays a vital role in regulating mPCa progression and RT resistance and might be a novel specific predictor for cancer RT.

Molecular regulation of lipid metabolism in Suaeda salsa.

Suaeda salsa is remarkable for its high oil content and abundant unsaturated fatty acids. In this study, the regulatory networks on fatty acid and lipid metabolism were constructed by combining the de novo transcriptome and lipidome data. Differentially expressed genes (DEGs) associated with lipids biosynthesis pathways were identified in the S. salsa transcriptome. DEGs involved in fatty acid and glycerolipids were generally up-regulated in leaf tissues. DEGs for TAG assembly were enriched in developing seeds, while DEGs in phospholipid metabolic pathways were enriched in root tissues. Polar lipids were extracted from S. salsa tissues and analyzed by lipidomics. The proportion of galactolipid MGDG was the highest in S. salsa leaves. The molar percentage of PG was high in the developing seeds, and the other main phospholipids had higher molar percentage in roots of S. salsa. The predominant C36:6 molecular species indicates that S. salsa is a typical 18:3 plant. The combined transcriptomic and lipidomic data revealed that different tissues of S. salsa were featured with DEGs associated with specific lipid metabolic pathways, therefore, represented unique lipid profiles. This study will be helpful on understanding lipid metabolism pathway and exploring the key genes involved in lipid synthesis in S. salsa.

Bovine blastocyst-like structures derived from stem cell cultures.

Understanding the mechanisms of blastocyst formation and implantation is critical for improving farm animal reproduction but is hampered by a limited supply of embryos. Here, we developed an efficient method to generate bovine blastocyst-like structures (termed blastoids) via assembling bovine trophoblast stem cells and expanded potential stem cells. Bovine blastoids resemble blastocysts in morphology, cell composition, single-cell transcriptomes, in vitro growth, and the ability to elicit maternal recognition of pregnancy following transfer to recipient cows. Bovine blastoids represent an accessible in vitro model for studying embryogenesis and improving reproductive efficiency in livestock species.

Dissecting embryonic and extra-embryonic lineage crosstalk with stem cell co-culture.

Faithful embryogenesis requires precise coordination between embryonic and extraembryonic tissues. Although stem cells from embryonic and extraembryonic origins have been generated for several mammalian species(Bogliotti et al., 2018; Choi et al., 2019; Cui et al., 2019; Evans and Kaufman, 1981; Kunath et al., 2005; Li et al., 2008; Martin, 1981; Okae et al., 2018; Tanaka et al., 1998; Thomson et al., 1998; Vandevoort et al., 2007; Vilarino et al., 2020; Yu et al., 2021b; Zhong et al., 2018), they are grown in different culture conditions with diverse media composition, which makes it difficult to study cross-lineage communication. Here, by using the same culture condition that activates FGF, TGF-ß and WNT signaling pathways, we derived stable embryonic stem cells (ESCs), extraembryonic endoderm stem cells (XENs) and trophoblast stem cells (TSCs) from all three founding tissues of mouse and cynomolgus monkey blastocysts. This allowed us to establish embryonic and extraembryonic stem cell co-cultures to dissect lineage crosstalk during early mammalian development. Co-cultures of ESCs and XENs uncovered a conserved and previously unrecognized growth inhibition of pluripotent cells by extraembryonic endoderm cells, which is in part mediated through extracellular matrix signaling. Our study unveils a more universal state of stem cell self-renewal stabilized by activation, as opposed to inhibition, of developmental signaling pathways. The embryonic and extraembryonic stem cell co-culture strategy developed here will open new avenues for creating more faithful embryo models and developing more developmentally relevant differentiation protocols.