Modelling post-implantation human development to yolk sac blood emergence.

Implantation of the human embryo begins a critical developmental stage that comprises profound events including axis formation, gastrulation and the emergence of haematopoietic system1,2. Our mechanistic knowledge of this window of human life remains limited due to restricted access to in vivo samples for both technical and ethical reasons3-5. Stem cell models of human embryo have emerged to help unlock the mysteries of this stage6-16. Here we present a genetically inducible stem cell-derived embryoid model of early post-implantation human embryogenesis that captures the reciprocal codevelopment of embryonic tissue and the extra-embryonic endoderm and mesoderm niche with early haematopoiesis. This model is produced from induced pluripotent stem cells and shows unanticipated self-organizing cellular programmes similar to those that occur in embryogenesis, including the formation of amniotic cavity and bilaminar disc morphologies as well as the generation of an anterior hypoblast pole and posterior domain. The extra-embryonic layer in these embryoids lacks trophoblast and shows advanced multilineage yolk sac tissue-like morphogenesis that harbours a process similar to distinct waves of haematopoiesis, including the emergence of erythroid-, megakaryocyte-, myeloid- and lymphoid-like cells. This model presents an easy-to-use, high-throughput, reproducible and scalable platform to probe multifaceted aspects of human development and blood formation at the early post-implantation stage. It will provide a tractable human-based model for drug testing and disease modelling.

A genetically inducible endothelial niche enables vascularization of human kidney organoids with multilineage maturation and emergence of renin expressing cells.

Vascularization plays a critical role in organ maturation and cell-type development. Drug discovery, organ mimicry, and ultimately transplantation hinge on achieving robust vascularization of in vitro engineered organs. Here, focusing on human kidney organoids, we overcame this hurdle by combining a human induced pluripotent stem cell (iPSC) line containing an inducible ETS translocation variant 2 (ETV2) (a transcription factor playing a role in endothelial cell development) that directs endothelial differentiation in vitro, with a non-transgenic iPSC line in suspension organoid culture. The resulting human kidney organoids show extensive endothelialization with a cellular identity most closely related to human kidney endothelia. Endothelialized kidney organoids also show increased maturation of nephron structures, an associated fenestrated endothelium with de novo formation of glomerular and venous subtypes, and the emergence of drug-responsive renin expressing cells. The creation of an engineered vascular niche capable of improving kidney organoid maturation and cell type complexity is a significant step forward in the path to clinical translation. Thus, incorporation of an engineered endothelial niche into a previously published kidney organoid protocol allowed the orthogonal differentiation of endothelial and parenchymal cell types, demonstrating the potential for applicability to other basic and translational organoid studies.

Biliary atresia is associated with polygenic susceptibility in ciliogenesis and planar polarity effector genes.

BACKGROUND & AIMS: Biliary atresia (BA) is poorly understood and leads to liver transplantation (LT), with the requirement for and associated risks of lifelong immunosuppression, in most children. We performed a genome-wide association study (GWAS) to determine the genetic basis of BA. METHODS: We performed a GWAS in 811 European BA cases treated with LT in US, Canadian and UK centers, and 4,654 genetically matched controls. Whole-genome sequencing of 100 cases evaluated synthetic association with rare variants. Functional studies included whole liver transcriptome analysis of 64 BA cases and perturbations in experimental models. RESULTS: A GWAS of common single nucleotide polymorphisms (SNPs), i.e. allele frequencies >1%, identified intronic SNPs rs6446628 in AFAP1 with genome-wide significance (p = 3.93E-8) and rs34599046 in TUSC3 at sub-threshold genome-wide significance (p = 1.34E-7), both supported by credible peaks of neighboring SNPs. Like other previously reported BA-associated genes, AFAP1 and TUSC3 are ciliogenesis and planar polarity effectors (CPLANE). In gene-set-based GWAS, BA was associated with 6,005 SNPs in 102 CPLANE genes (p = 5.84E-15). Compared with non-CPLANE genes, more CPLANE genes harbored rare variants (allele frequency <1%) that were assigned Human Phenotype Ontology terms related to hepatobiliary anomalies by predictive algorithms, 87% vs. 40%, p <0.0001. Rare variants were present in multiple genes distinct from those with BA-associated common variants in most BA cases. AFAP1 and TUSC3 knockdown blocked ciliogenesis in mouse tracheal cells. Inhibition of ciliogenesis caused biliary dysgenesis in zebrafish. AFAP1 and TUSC3 were expressed in fetal liver organoids, as well as fetal and BA livers, but not in normal or disease-control livers. Integrative analysis of BA-associated variants and liver transcripts revealed abnormal vasculogenesis and epithelial tube formation, explaining portal vein anomalies that co-exist with BA. CONCLUSIONS: BA is associated with polygenic susceptibility in CPLANE genes. Rare variants contribute to polygenic risk in vulnerable pathways via unique genes. IMPACT AND IMPLICATIONS: Liver transplantation is needed to cure most children born with biliary atresia, a poorly understood rare disease. Transplant immunosuppression increases the likelihood of life-threatening infections and cancers. To improve care by preventing this disease and its progression to transplantation, we examined its genetic basis. We find that this disease is associated with both common and rare mutations in highly specialized genes which maintain normal communication and movement of cells, and their organization into bile ducts and blood vessels during early development of the human embryo. Because defects in these genes also cause other birth defects, our findings could lead to preventive strategies to lower the incidence of biliary atresia and potentially other birth defects.

[Clinicopathological analysis of pseudostratified ependymal tubules in ovarian mature teratoma].

Objective: To investigate the morphology and immunohistochemical (IHC) expression of pseudostratified ependymal tubules in ovarian mature teratoma (MT). Methods: Five cases of ovarian MT with pseudostratified ependymal tubules were collected from Shenzhen Hospital(Futian) of Guangzhou University of Chinese Medicine and the Eighth Affiliated Hospital of Sun Yat-sen University from March 2019 to March 2022. In addition, 15 cases of ovarian MT with monolayer ependymal epithelium from Shenzhen Hospital (Futian) of Guangzhou University of Chinese medicine and seven cases of immature teratoma (IMT) from Hainan Provincial People's Hospital from March 2019 to March 2022 were collected as control. The morphologic characteristics and immunophenotypes of pseudostratified ependymal tubules, monolayer ependymal epithelium, and primitive neural epithelial tubules were observed and compared by H&E stain and IHC expression pattern of genes related to the differentiation status of neuroepithelium, namely SALL4, Glypican3, nestin, SOX2, Foxj1, and Ki-67. Results: Mean age of the five patients of ovarian MT with pseudostratified ependymal tubules was 26 years (range from 19 to 31 years). Two tumors were located in the left ovary and three in the right. All five cases were excised, and clinical follow-up was available (mean follow-up 1.5 years; range 0.5 to 3 years). No recurrence was noted in any cases. The pseudostratified ependymal tubules of ovarian MT, which were lined with columnar or oval epithelia up to 4-6 layers, were morphologically similar to the primitive neuroepithelial tubules of IMT and different from monolayer ependymal epithelium of ovarian MT. By immunohistochemistry, SALL4 and Glypican3 were negative, Foxj1 was positive and Ki-67 index was lower in the pseudostratified ependymal tubules and the monolayer ependymal epithelium of ovarian MT. However, the primitive neuroepithelial tubules of IMT showed variably expression of SALL4 and Glypican3, were negative for Foxj1 and high Ki-67 index. All the above three groups expressed nestin and SOX2. Conclusions: The pseudostratified ependymal tubules of ovarian MT, which have morphological similarities to the primitive neuroepithelial tubules of IMT, are similar to the monolayer ependymal epithelia of the MT in immunophenotype. IHC assessment of Foxj1 and Ki-67 is helpful to differentiate the pseudostratified ependymal tubules of ovarian MT from the primitive neuroepithelial tubules of IMT.

Nonsense mutations in KRT1 caused recessive epidermolytic palmoplantar keratoderma with knuckle pads.

BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is characterized by diffuse hyperkeratosis affecting palms and soles with suprabasal epidermolysis or vacuolar degeneration histopathologically. The disorder is caused by heterozygous mutations in KRT9 or KRT1. Dominant-negative mutations in KRT1 could also result in epidermolytic ichthyosis with EPPK, a more severe entity affecting the entire body. OBJECTIVE: To investigate the genetic basis and pathogenesis of two unrelated patients with EPPK and knuckle pads, both of whom were born to consanguineous parents of Chinese origin. METHODS: Next-generation sequencing was applied to the two patients using genomic DNA extracted from peripheral blood. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR), immunofluorescence (IF) staining and Western blot (WB) were employed to evaluate mRNA and protein expression level. Ultrastructural changes of skin lesion were analysed using transmission electron microscopy. RESULTS: Two novel homozygous mutations, c.457C>T (p.Gln153*) and c.33C>G (p.Tyr11*) in KRT1, were identified in patients 1 and 2 respectively. The nonsense mutations were predicted to result in nonsense-mediated mRNA decay and absence of keratin 1, which was confirmed in the skin lesions from patient 1. Upregulated keratin 2 was detected both in the affected and unaffected skin samples from patient 1, while the protein abundance and distribution pattern of keratin 10 remained unchanged. An aberrant and clumped staining pattern of keratin 9 was noted in the palmar skin of patient 1. CONCLUSIONS: Homozygous 'knockout' mutations in KRT1 resulted in EPPK with knuckle pads rather than epidermolytic ichthyosis. We speculated that sparing of non-acral skin might be due to compensatory effect of keratin 2 upregulation by forming heterodimer with keratin 10.

[Research status of the innervation of prostate cancer and its potential clinical applications for nerve-targeted therapy].

Nerve fibers are important component in tumor microenvironment (TME) and have been shown to promote the early development of the prostate cancer and metastasis of advanced prostate cancer. Besides, it also activates an angio-metabolic switch, altering the endothelial cell metabolism to trigger angiogenesis. Most studies have showed that nerve infiltration in prostate cancer may be regulated by a variety of nerve growth factors secreted by cancer cells.However, surprisingly, neurons in the TME could also be neural progenitors originating from the subventricular zone. Recently, the effects of tumor-associated neuro-immune signal dysfunction on cancer promotion has gradually become a new focus. Therefore, elucidating the molecular and cellular mechanisms of nerve and its signaling in prostate cancer will help improve the value of clinical application of nerve targeted therapy.

An enhanced CRISPR repressor for targeted mammalian gene regulation.

The RNA-guided endonuclease Cas9 can be converted into a programmable transcriptional repressor, but inefficiencies in target-gene silencing have limited its utility. Here we describe an improved Cas9 repressor based on the C-terminal fusion of a rationally designed bipartite repressor domain, KRAB-MeCP2, to nuclease-dead Cas9. We demonstrate the system's superiority in silencing coding and noncoding genes, simultaneously repressing a series of target genes, improving the results of single and dual guide RNA library screens, and enabling new architectures of synthetic genetic circuits.

[Prognostic value of Montreal Cognitive Assessment in heart failure patients].

Objective: To explore the occurrence of cognitive impairment in Chinese heart failure (HF) patients and it's impact on prognosis. Methods: In this prospective observational study, a total of 990 HF patients were enrolled from 24 hospitals in China during December 2012 to November 2014. All patients were administrated with the interview-format Montreal Cognitive Assessment (MoCA), according to which they were divided into MoCA<26 (with cognitive impairment) group and MoCA≥26 (without cognitive impairment) group. Baseline data were collected and a 1-year follow up was carried out. Univariate and multivariate logistic or Cox regression were performed for 1-year outcomes. Results: Cognitive impairment was evidenced in 628 patients (63.4%) and they were more likely to be older, female, and with higher proportion of New York Heart Association(NYHA) class Ⅲ-Ⅳ, chronic obstructive pulmonary disease (COPD), ischemic heart disease, while body mass index (BMI), education level, and medical insurance rate were lower (all P<0.05) as compared to patients in MoCA≥26 group. The rate of percutaneous intervention, device implantation, cardiac surgery and evidence-based medications were significantly lower in MoCA<26 group than in MoCA≥26 group (all P<0.05). During the 1-year follow up, patients in the MoCA<26 group had higher all-cause mortality (10.2%(64/628) vs. 2.2%(8/362), P<0.01), cardiovascular mortality (5.9%(37/628) vs. 0.8%(3/362), P<0.01) and major adverse cardiac and cerebrovascular events (MACCE) (9.6%(60/628) vs. 2.5%(8/362), P<0.01) than patients in the MoCA≥26 group. In univariate regression, MoCA<26 was associated with increased all-cause mortality (HR(95%CI):4.739(2.272-9.885), P<0.01), cardiovascular mortality (HR(95%CI):7.258(2.237-23.548), P=0.001) and MACCE (OR(95%CI):4.143(2.031-8.453), P<0.01). After adjustment by multivariate regression, MoCA<26 was indicated as an independent risk factor for all-cause mortality (HR(95%CI): 6.387(2.533-16.104), P<0.01), cardiovascular mortality (HR(95%CI): 10.848(2.586-45.506), P=0.001) and MACCE (OR(95%CI): 4.081(1.299-12.816), P=0.016), while not for re-hospitalization for HF (OR(95%CI):1.010(0.700-1.457), P=0.957). Conclusions: Cognitive impairment is common in HF patients,and it is an independent prognostic factor for 1-year outcomes. Routine cognitive function assessment and active intervention are thus recommended for HF patients.

[Fecal microbiota transplantation for the treatment of ulcerative colitis: a Meta-analysis].

Objective: We aimed to evaluate the efficacy and safety of fecal microbiota transplantation (FMT) for the treatment of ulcerative colitis (UC) in this Meta-analysis. Methods: Literature related to FMT for the treatment of UC from PubMed, Embase, Cochrane databases, CNKI, VIP and Wanfang Data were searched and screened with update study in May 2018. Two independent investigators extracted information according to inclusion and exclusion criteria. The Meta-analysis was conducted by Stata 12.0 software. Results: A total of 4 randomized controlled trials (RCTs) and 19 non-randomized controlled trials (non-RCTs) including 536 participants met the inclusion criteria. Meta-analysis of RCTs showed that FMT significantly increased the clinical remission rate (OR=2.47, 95%CI 1.40-4.33, P=0.02) and clinical response rate (OR=1.86, 95%CI 1.15-3.02, P=0.01) in UC patients without increasing the incidence of severe adverse effects (OR=1.40, 95%CI 0.51-3.79, P=0.51). The results from 19 non-RCTs showed that clinical remission rate in UC patients with FMT treatment was 20%(95%CI 13%-28%) and the clinical response rate was 50%(95%CI 36%-65%). All adverse events were graded as mild and self-resolving. No FMT-related severe adverse effects were reported. Conclusions: Our analysis suggests that FMT is a safe and effective method for the treatment of UC. Considering several limitations of this Meta-analysis and previous clinical trials, further large-scale multicenter RCTs are still required to further verify the conclusion.

Assessment of serum Golgi protein 73 as a biomarker for the diagnosis of significant fibrosis in patients with chronic HBV infection.

Transient elastography (TE) is accurate in staging fibrosis noninvasively. However, a reliable serum biomarker with comparable accuracy is also important, especially when TE is unreliable/unavailable. Therefore, we aimed to evaluate the diagnostic performance of serum Golgi protein 73 (GP73) for significant fibrosis in patients with chronic HBV infection. A total of 801 patients with chronic liver disease (CLD; 492 chronic HBV infection and 309 non-HBV liver disease) with liver biopsy performance were enrolled. Healthy controls (n = 180) and hepatocellular carcinoma (HCC) patients (n = 85) were included for comparisons. Liver biopsy was used as the reference method for fibrosis staging. Serum GP73 level was measured in duplicate in double-blind fashion. Serum GP73 was highest in HCC but also significantly higher in chronic hepatitis B than in healthy controls. The elevation of serum GP73 in non-HCC patients was significantly associated with the presence of significant fibrosis independently of ALT level, liver stiffness (LS) value, inflammation grade and other confounding factors. The diagnostic performance of serum GP73 was accurate in antiviral-naïve HBV patients (area under the receiver operating curve [AUROC], 0.76 95% CI: 0.72-0.81) but not in patients with ongoing antiviral treatment (AUROC, 0.60). The utility of serum GP73 was also confirmed in non-HBV CLD (AUROC, 0.80 95% CI: 0.75-0.85). Serum GP73 was comparable to LS (AUROC, 0.78 95% CI: 0.73-0.82) and significantly better than AST to platelet ratio index (APRI) (AUROC, 0.67 95% CI: 0.62-0.72) and FIB-4 (AUROC, 0.68 95% CI: 0.63-0.73). In conclusion, serum GP73 is an accurate serum marker for significant fibrosis in chronic HBV infection, with higher accuracy than APRI and FIB-4. Serum GP73 is potentially a complementary tool for TE when evaluating the necessity of antiviral treatment, particularly in patients without definite antiviral indication.

[Influence of manganese exposure via intracerebral injection on behavioristics and substantia nigra dopaminergic neurons in rats].

OBJECTIVE: To investigate the changes in behavioristics, substantia nigra tyrosine hydroxylase (TH) immunoreactive cells, and ultrastructure of substantia nigra neurons in rats after manganese exposure via intracerebral injection. METHODS: A total of 72 healthy male Sprague-Dawley rats were randomly divided into exposure group and control group, with 36 rats in each group. The stereotactic technique was used for injection of 1 µl MnCl2·4H2O (1 mol/L) into the corpus striatum in the exposure group, and the control group was injected with the same volume of normal saline. The changes in rotational behavior, number of TH immunoreactive cells in the substantia nigra, and ultrastructure of the substantia nigra induced by apomorphine were observed at 8 hours and 1, 3, 7, 15, and 30 days after injection, and this measure was compared with manganese exposure via intraperitoneal injection. RESULTS: After apomorphine induction for 30 minutes, the exposure group showed a gradual increase in the number of rotations over the time of manganese exposure (F= 176.921, P<0.01) and a significantly higher number of rotations than the control group (F=482.654, P<0.01). The exposure group showed a gradual reduction in the mean A value of TH immunoreactive cells in the injured substantia nigra over the time of exposure (F=12.009, P<0.01) , and this value differed significantly between the injured substantia nigra in the exposure group and the contralateral substantia nigra in the exposure group and the injured side in the control group (F=36.131, P<0.01). At 3, 7, 15, and 30 days after exposure, the injured substantia nigra showed a significantly lower mean A value of TH immunoreactive cells than the contralateral side in the exposure group (all P<0.01). At 7, 15, and 30 days, the injured substantia nigra in the exposure group showed a significantly lower mean A value than the injured side in the control group (all P<0.01). After manganese exposure, substantia nigra neurons showed the changes including mitochondrial swelling, dilatation of the endoplasmic reticulum, and demyelination of nerve fibers in different stages, which suggested the dynamic process of dopaminergic neuron injuries. Compared with manganese exposure via intraperitoneal injection, manganese exposure via intracerebral injection can induce behavioral changes and injuries of the substantia nigra-striatum system more quickly. CONCLUSION: Manganese exposure via intracerebral injection induces behavioral changes and injuries of substantia nigra dopaminergic neurons in rats within a short time.

Infections in patients hospitalized for fever as related to duration and other predictors at admittance.

PURPOSE: To find the underlying diagnoses of patients admitted to a medical department with symptoms of fever to ascertain whether the duration of fever, temperature readings, and common laboratory tests could give a clue to the final diagnosis. METHODS: A retrospective study of the records of 299 patients admitted to the Medical Department, Haukeland University Hospital from July 1st, 2001 until June 30th, 2004 for fever without any diagnosis suggesting the cause of the fever. RESULTS AND CONCLUSIONS: Infections were the most common diagnoses, but the proportion of patients with infections declined with increasing duration of fever before admission (63.7 % when <7 days, 45.8 % when >21 days). A group of patients on immunosuppressive therapy were all hospitalized within 1 week from the debut of fever, and their causes of fever were comparable to those of non-immunocompromised patients with fever of the same duration. With fever <7 days, patients with bacterial or viral infection had higher maximum temperatures (medians 39.2 and 38.9 °C, respectively) than those without infection (median 38.0 °C). Patients with bacterial infection had higher C-reactive protein (CRP) levels than patients in the other groups, whereas viral infection was associated with higher lymphocyte counts. The neutrophil:lymphocyte ratio was higher in patients with fever due to bacterial infections than in those with viral infections. For patients with fever for <1 week, neutrophil [area under the curve (AUC) 0.723], white blood cell (WBC, AUC 0.692), and monocyte (AUC 0.691) counts and CRP levels (AUC 0.684) were the best single indicators of bacterial infection.

Essential function of Gli2 and Gli3 in the formation of lung, trachea and oesophagus.

Foregut malformations (oesophageal atresia, tracheo-oesophageal fistula, lung anomalies and congenital stenosis of the oesophagus and trachea) are relatively common anomalies occurring in 1 in 2,000-5,000 live births, although their aetiology is poorly understood. The secreted glycoprotein Sonic hedgehog (Shh) has been suggested to act as an endodermal signal that controls hindgut patterning and lung growth. In mice, three zinc-finger transcription factors, Gli1, Gli2 and Gli3, have been implicated in the transduction of Shh signal. We report here that mutant mice lacking Gli2 function exhibit foregut defects, including stenosis of the oesophagus and trachea, as well as hypoplasia and lobulation defects of the lung. A reduction of 50% in the gene dosage of Gli3 in a Gli2-/- background resulted in oesophageal atresia with tracheo-oesophageal fistula and a severe lung phenotype. Mutant mice lacking both Gli2 and Gli3 function did not form oesophagus, trachea and lung. These results indicate that Gli2 and Gli3 possess specific and overlapping functions in Shh signalling during foregut development, and suggest that mutations in GLI genes may be involved in human foregut malformations.

Therapeutic Cell Repopulation of the Liver: From Fetal Rat Cells to Synthetic Human Tissues.

Progenitor cells isolated from the fetal liver can provide a unique cell source to generate new healthy tissue mass. Almost 20 years ago, it was demonstrated that rat fetal liver cells repopulate the normal host liver environment via a mechanism akin to cell competition. Activin A, which is produced by hepatocytes, was identified as an important player during cell competition. Because of reduced activin receptor expression, highly proliferative fetal liver stem/progenitor cells are resistant to activin A and therefore exhibit a growth advantage compared to hepatocytes. As a result, transplanted fetal liver cells are capable of repopulating normal livers. Important for cell-based therapies, hepatic stem/progenitor cells containing repopulation potential can be separated from fetal hematopoietic cells using the cell surface marker δ-like 1 (Dlk-1). In livers with advanced fibrosis, fetal epithelial stem/progenitor cells differentiate into functional hepatic cells and out-compete injured endogenous hepatocytes, which cause anti-fibrotic effects. Although fetal liver cells efficiently repopulate the liver, they will likely not be used for human cell transplantation. Thus, utilizing the underlying mechanism of repopulation and developed methods to produce similar growth-advantaged cells in vitro, e.g., human induced pluripotent stem cells (iPSCs), this approach has great potential for developing novel cell-based therapies in patients with liver disease. The present review gives a brief overview of the classic cell transplantation models and various cell sources studied as donor cell candidates. The advantages of fetal liver-derived stem/progenitor cells are discussed, as well as the mechanism of liver repopulation. Moreover, this article reviews the potential of in vitro developed synthetic human fetal livers from iPSCs and their therapeutic benefits.

Platform-agnostic CellNet enables cross-study analysis of cell fate engineering protocols.

Optimization of cell engineering protocols requires standard, comprehensive quality metrics. We previously developed CellNet, a computational tool to quantitatively assess the transcriptional fidelity of engineered cells compared with their natural counterparts, based on bulk-derived expression profiles. However, this platform and others were limited in their ability to compare data from different sources, and no current tool makes it easy to compare new protocols with existing state-of-the-art protocols in a standardized manner. Here, we utilized our prior application of the top-scoring pair transformation to build a computational platform, platform-agnostic CellNet (PACNet), to address both shortcomings. To demonstrate the utility of PACNet, we applied it to thousands of samples from over 100 studies that describe dozens of protocols designed to produce seven distinct cell types. We performed an in-depth examination of hepatocyte and cardiomyocyte protocols to identify the best-performing methods, characterize the extent of intra-protocol and inter-lab variation, and identify common off-target signatures, including a surprising neural/neuroendocrine signature in primary liver-derived organoids. We have made PACNet available as an easy-to-use web application, allowing users to assess their protocols relative to our database of reference engineered samples, and as open-source, extensible code.

Modelling Human Post-Implantation Development via Extra-Embryonic Niche Engineering.

Implantation of the human embryo commences a critical developmental stage that comprises profound morphogenetic alteration of embryonic and extra-embryonic tissues, axis formation, and gastrulation events. Our mechanistic knowledge of this window of human life remains limited due to restricted access to in vivo samples for both technical and ethical reasons. Additionally, human stem cell models of early post-implantation development with both embryonic and extra-embryonic tissue morphogenesis are lacking. Here, we present iDiscoid, produced from human induced pluripotent stem cells via an engineered a synthetic gene circuit. iDiscoids exhibit reciprocal co-development of human embryonic tissue and engineered extra-embryonic niche in a model of human post-implantation. They exhibit unanticipated self-organization and tissue boundary formation that recapitulates yolk sac-like tissue specification with extra-embryonic mesoderm and hematopoietic characteristics, the formation of bilaminar disc-like embryonic morphology, the development of an amniotic-like cavity, and acquisition of an anterior-like hypoblast pole and posterior-like axis. iDiscoids offer an easy-to-use, high-throughput, reproducible, and scalable platform to probe multifaceted aspects of human early post-implantation development. Thus, they have the potential to provide a tractable human model for drug testing, developmental toxicology, and disease modeling.

Genetically engineering endothelial niche in human kidney organoids enables multilineage maturation, vascularization and de novo cell types.

Vascularization plays a critical role in organ maturation and cell type development. Drug discovery, organ mimicry, and ultimately transplantation in a clinical setting thereby hinges on achieving robust vascularization of in vitro engineered organs. Here, focusing on human kidney organoids, we overcome this hurdle by combining an inducible ETS translocation variant 2 (ETV2) human induced pluripotent stem cell (iPSC) line, which directs endothelial fate, with a non-transgenic iPSC line in suspension organoid culture. The resulting human kidney organoids show extensive vascularization by endothelial cells with an identity most closely related to endogenous kidney endothelia. Vascularized organoids also show increased maturation of nephron structures including more mature podocytes with improved marker expression, foot process interdigitation, an associated fenestrated endothelium, and the presence of renin+ cells. The creation of an engineered vascular niche capable of improving kidney organoid maturation and cell type complexity is a significant step forward in the path to clinical translation. Furthermore, this approach is orthogonal to native tissue differentiation paths, hence readily adaptable to other organoid systems and thus has the potential for a broad impact on basic and translational organoid studies.