Protected high risk percutaneous coronary intervention-Impella 5.0 as a single-access technique: a case report.

Background: Patients requiring coronary intervention after acute myocardial infarction, with decompensated heart failure and multiple co-morbidities, present a challenging clinical scenario. Addressing such high-risk cases has been a marked increase in the simultaneous support using microaxial flow pump devices, providing a crucial haemodynamic support during procedures. Case summary: We report the case of a 58-year-old man, with a non-ST-segment elevation myocardial infarction in the context of a peripheral vascular surgery. Echocardiography revealed severely reduced left ventricular function and cardiac magnetic resonance imaging demonstrated transmural scars in all but left anterior descending artery area. The patient was of extreme high surgical risk due to the multiple co-morbidities, acute decompensation heart failure, and peripheral artery disease, and, therefore, the heart team preferred protected percutaneous coronary intervention (PCI) over coronary artery bypass graft for revascularization. The peripheral artery disease included severely calcified ascending aorta, occlusions of both femoral arteries, the left subclavian artery, and the right radial artery. Taken together, the heart team agreed on a hybrid approach with surgical implantation of Impella 5.0 via the left subclavian artery, by a single-access technique. Following the intervention procedure, haemostasis of the vascular prosthesis was achieved by an angio-seal technique without complications. The patient recovered satisfactorily, with improved left ventricular function, and discharged 10 days post-procedure. Discussion: The single-access high-risk PCI technique offers a standardized approach for microaxial flow pump devices such as Impella 5.0 and PCI. The subclavian artery as a single-access route for high-risk PCI has demonstrated safety and efficacy.

Walking as a cultural act and a profit for the landscape. A case study in the Iberian Peninsula.

Walking as a means of travel, when done voluntarily, becomes a cultural act that can have a beneficial effect both for the people who carry out the routes and for the space itself that is walked on. The fact of moving at a slow speed allow us to recover a more appropriate pace to enjoy the landscape, to reconnect with nature and with the position of human in the world, while improving our health. In contemporary society, some cultural tourist routes have become successful destinations, with the continuous arrival of thousands of visitors throughout the year. Thus, the historical cultural route Way of St. James has become a globally successful cultural tourism product. Close to this destination, the Ribeira Sacra, that has been recently designated by the regional government as a Cultural Landscape, with the intention of preserving its historical legacy, may be in the future a privileged destination in Galicia for walking. The research carried out allows us to ensure that this fact, taking long walks following routes with a rich cultural content, has a positive impact on the space from two different processes that are reinforced as the routes become more popular. First, from the recovery and promotion of an alternative communication network between different places. And second, through a series of laws and regulations that protect historic trails and adjacent landscapes.

Synaptotagmin-13 orchestrates pancreatic endocrine cell egression and islet morphogenesis.

During pancreas development endocrine cells leave the ductal epithelium to form the islets of Langerhans, but the morphogenetic mechanisms are incompletely understood. Here, we identify the Ca2+-independent atypical Synaptotagmin-13 (Syt13) as a key regulator of endocrine cell egression and islet formation. We detect specific upregulation of the Syt13 gene and encoded protein in endocrine precursors and the respective lineage during islet formation. The Syt13 protein is localized to the apical membrane of endocrine precursors and to the front domain of egressing endocrine cells, marking a previously unidentified apical-basal to front-rear repolarization during endocrine precursor cell egression. Knockout of Syt13 impairs endocrine cell egression and skews the α-to-ß-cell ratio. Mechanistically, Syt13 is a vesicle trafficking protein, transported via the microtubule cytoskeleton, and interacts with phosphatidylinositol phospholipids for polarized localization. By internalizing a subset of plasma membrane proteins at the front domain, including α6ß4 integrins, Syt13 modulates cell-matrix adhesion and allows efficient endocrine cell egression. Altogether, these findings uncover an unexpected role for Syt13 as a morphogenetic driver of endocrinogenesis and islet formation.

Melanosis neurocutánea: reporte de un caso y revisión de la literatura / Neurocutaneous melanosis. Case report and literature review / Melanose neurocutânea: relato de caso e revisão da literatura

RESUMEN Introducción: la melanosis neurocutánea es un trastorno congénito no hereditario que se caracteriza por la asociación de nevus pigmentados múltiples o de gran tamaño y una excesiva proliferación de melanocitos en el sistema nervioso central. La incidencia es similar en ambos sexos, y se observa historia familiar de melanoma en un único caso. Presentación del caso: se trata de un neonato masculino que nace en Hospital General de Luanda en Angola, con mancha melánica gigante que se extiende desde el cuello, cara, tórax, abdomen, espalda y miembros superiores, requiere una vigilancia de las lesiones dérmicas y un control de las crisis convulsivas. Discusión: se realizaron revisiones de la literatura médica disponible sobre el tema, consultando el programa de genética Oxford, y se tomaron fotos de las características clínicas sobresalientes. Por lo general los síntomas neurológicos son de temprana aparición en la etapa neonatal o de lactante con presencia de convulsiones de difícil control, al crear un pronóstico reservado. Conclusiones: se considera importante el seguimiento del neurodesarrollo de forma multidisciplinario para intervención oportuna si fuera necesario.

ABSTRACT Introduction: neurocutaneous melanosis is a non-hereditary congenital disorder characterized by the association of multiple or large pigmented nevi and an excessive proliferation of melanocytes in the central nervous system. The incidence is similar in both sexes, and a family history of melanoma is observed in a single case. Case presentation: this is a male neonate born at the General Hospital of Luanda in Angola, with a giant melanic spot that extends from the neck, face, chest, abdomen, back and upper limbs, requires surveillance of dermal lesions and control of seizures. Discussion: reviews of the available medical literature on the subject were conducted, consulting the Oxford genetics program, and photos of outstanding clinical features were taken. Usually the neurological symptoms are of early onset in the neonatal or infant stage with the presence of seizures that are difficult to control, creating a reserved prognosis. Conclusions: it is considered important to monitor neurodevelopment in a multidisciplinary way for timely intervention if necessary.

RESUMO Introdução: a melanose neurocutânea é uma doença congênita não hereditária caracterizada pela associação de nevi pigmentado múltiplo ou grande e uma proliferação excessiva de melanócitos no sistema nervoso central. A incidência é semelhante em ambos os sexos, e um histórico familiar de melanoma é observado em um único caso. Apresentação do caso: trata-se de um recém-nascido no Hospital Geral de Luanda, em Angola, com um ponto melanico gigante que se estende do pescoço, rosto, tórax, abdômen, costas e membros superiores, requer vigilância de lesões dérmicas e controle de convulsões. Discussão: foram realizadas revisões da literatura médica disponível sobre o tema, consultando o programa de genética de Oxford e fotos de características clínicas de destaque. Geralmente os sintomas neurológicos são de início precoce no estágio neonatal ou infantil com a presença de convulsões de difícil controle, criando um prognóstico reservado. Conclusões: é considerado importante monitorar o neurodesenvolvimento de forma multidisciplinar para intervenção oportuna, se necessário.

Melanosis neurocutánea: reporte de un caso y revisión de la literatura / Neurocutaneous melanosis. Case report and literature review

Introducción: la melanosis neurocutánea es un trastorno congénito no hereditario que se caracteriza por la asociación de nevus pigmentados múltiples o de gran tamaño y una excesiva proliferación de melanocitos en el sistema nervioso central. La incidencia es similar en ambos sexos, y se observa historia familiar de melanoma en un único caso. Presentación del caso: se trata de un neonato masculino que nace en Hospital General de Luanda en Angola, con mancha melánica gigante que se extiende desde el cuello, cara, tórax, abdomen, espalda y miembros superiores, requiere una vigilancia de las lesiones dérmicas y un control de las crisis convulsivas. Discusión: se realizaron revisiones de la literatura médica disponible sobre el tema, consultando el programa de genética Oxford, y se tomaron fotos de las características clínicas sobresalientes. Por lo general los síntomas neurológicos son de temprana aparición en la etapa neonatal o de lactante con presencia de convulsiones de difícil control, al crear un pronóstico reservado. Conclusiones: se considera importante el seguimiento del neurodesarrollo de forma multidisciplinario para intervención oportuna si fuera necesario(AU)

Introduction: neurocutaneous melanosis is a non-hereditary congenital disorder characterized by the association of multiple or large pigmented nevi and an excessive proliferation of melanocytes in the central nervous system. The incidence is similar in both sexes, and a family history of melanoma is observed in a single case. Case presentation: this is a male neonate born at the General Hospital of Luanda in Angola, with a giant melanic spot that extends from the neck, face, chest, abdomen, back and upper limbs, requires surveillance of dermal lesions and control of seizures. Discussion: reviews of the available medical literature on the subject were conducted, consulting the Oxford genetics program, and photos of outstanding clinical features were taken. Usually the neurological symptoms are of early onset in the neonatal or infant stage with the presence of seizures that are difficult to control, creating a reserved prognosis. Conclusions: it is considered important to monitor neurodevelopment in a multidisciplinary way for timely intervention if necessary(EU)

Role of acquired von Willebrand syndrome in the development of bleeding complications in patients treated with Impella RP devices.

Axial flow pumps are standard treatment in cases of cardiogenic shock and high-risk interventions in cardiology and cardiac surgery, although the optimal anticoagulation strategy remains unclear. We evaluated whether laboratory findings could predict bleeding complications and acquired von Willebrand syndrome (avWS) among patients who were treated using axial flow pumps. We retrospectively evaluated 60 consecutive patients who received Impella devices (Impella RP: n = 20, Impella CP/5.0: n = 40; Abiomed Inc., Danvers, USA) between January 2019 and December 2020. Thirty-two patients (53.3%) experienced major or fatal bleeding complications (Bleeding Academic Research Consortium score of > 3) despite intravenous heparin being used to maintain normal activated partial thromboplastin times (40-50 s). Extensive testing was performed for 28 patients with bleeding complications (87.5%). Relative to patients with left ventricular support, patients with right ventricular support were less likely to develop avWS (87.5% vs. 58.8%, p = 0.035). Bleeding was significantly associated with avWS (odds ratio [OR]: 20.8, 95% confidence interval [CI]: 3.3-128.5; p = 0.001) and treatment duration (OR: 1.3, 95% CI 1.09-1.55; p = 0.003). Patients with avWS had longer Impella treatment than patients without avWS (2 days [1-4.7 days] vs. 7.3 days [3.2-13.0 days]). Bleeding complications during Impella support were associated with avWS in our cohort, while aPTT monitoring was not sufficient to prevent bleeding complications. A more targeted anticoagulation monitoring might be needed for patients who receive Impella devices.

Molecular and Mechanical Cues for Somite Periodicity.

Somitogenesis refers to the segmentation of the paraxial mesoderm, a tissue located on the back of the embryo, into regularly spaced and sized pieces, i.e., the somites. This periodicity is important to assure, for example, the formation of a functional vertebral column. Prevailing models of somitogenesis are based on the existence of a gene regulatory network capable of generating a striped pattern of gene expression, which is subsequently translated into periodic tissue boundaries. An alternative view is that the pre-pattern that guides somitogenesis is not chemical, but of a mechanical origin. A striped pattern of mechanical strain can be formed in physically connected tissues expanding at different rates, as it occurs in the embryo. Here we argue that both molecular and mechanical cues could drive somite periodicity and suggest how they could be integrated.

Synaptotagmin-13 Is a Neuroendocrine Marker in Brain, Intestine and Pancreas.

Synaptotagmin-13 (Syt13) is an atypical member of the vesicle trafficking synaptotagmin protein family. The expression pattern and the biological function of this Ca2+-independent protein are not well resolved. Here, we have generated a novel Syt13-Venus fusion (Syt13-VF) fluorescence reporter allele to track and isolate tissues and cells expressing Syt13 protein. The reporter allele is regulated by endogenous cis-regulatory elements of Syt13 and the fusion protein follows an identical expression pattern of the endogenous Syt13 protein. The homozygous reporter mice are viable and fertile. We identify the expression of the Syt13-VF reporter in different regions of the brain with high expression in tyrosine hydroxylase (TH)-expressing and oxytocin-producing neuroendocrine cells. Moreover, Syt13-VF is highly restricted to all enteroendocrine cells in the adult intestine that can be traced in live imaging. Finally, Syt13-VF protein is expressed in the pancreatic endocrine lineage, allowing their specific isolation by flow sorting. These findings demonstrate high expression levels of Syt13 in the endocrine lineages in three major organs harboring these secretory cells. Collectively, the Syt13-VF reporter mouse line provides a unique and reliable tool to dissect the spatio-temporal expression pattern of Syt13 and enables isolation of Syt13-expressing cells that will aid in deciphering the molecular functions of this protein in the neuroendocrine system.

A point mutation in the Pdia6 gene results in loss of pancreatic ß-cell identity causing overt diabetes.

OBJECTIVE: Protein disulfide isomerases (PDIs) are oxidoreductases that are involved in catalyzing the formation and rearrangement of disulfide bonds during protein folding. One of the PDI members is the PDI-associated 6 (PDIA6) protein, which has been shown to play a vital role in ß-cell dysfunction and diabetes. However, very little is known about the function of this protein in ß-cells in vivo. This study aimed to describe the consequences of a point mutation in Pdia6 on ß-cell development and function. METHODS: We generated an ENU mouse model carrying a missense mutation (Phe175Ser) in the second thioredoxin domain of the Pdia6 gene. Using biochemical and molecular tools, we determined the effects of the mutation on the ß-cell development at embryonic day (E)18.5 and ß-cell identity as well as function at postnatal stages. RESULTS: Mice homozygous for the Phe175Ser (F175S) mutation were mildly hyperglycemic at weaning and subsequently became hypoinsulinemic and overtly diabetic at the adult stage. Although no developmental phenotype was detected during embryogenesis, mutant mice displayed reduced insulin-expressing ß-cells at P14 and P21 without any changes in the rate of cell death and proliferation. Further analysis revealed an increase in BiP and the PDI family member PDIA4, but without any concomitant apoptosis and cell death. Instead, the expression of prominent markers of ß-cell maturation and function, such as Ins2, Mafa, and Slc2a2, along with increased expression of α-cell markers, Mafb, and glucagon was observed in adult mice, suggesting loss of ß-cell identity. CONCLUSIONS: The results demonstrate that a global Pdia6 mutation renders mice hypoinsulinemic and hyperglycemic. This occurs due to the loss of pancreatic ß-cell function and identity, suggesting a critical role of PDIA6 specifically for ß-cells.

A revision of vulture feeding classification.

Pioneering fieldwork identified the existence of three feeding groups in vultures: gulpers, rippers and scrappers. Gulpers engulf soft tissue from carcasses and rippers tear off pieces of tough tissue (skin, tendons, muscle), whereas scrappers peck on small pieces of meat they find on and around carcasses. It has been shown that these feeding preferences are reflected in the anatomy of the skull and neck. Here, we demonstrate that these three feeding groups also emerge when body core and limb bones are added to the analysis. However, the resulting classification differs from that which is based on skull morphology for three species, namely Gypaetus barbatus (Linnaeus, 1758), Gypohierax angolensis (Gmelin, 1788) and Gyps indicus (Scopoli, 1786). The proposed classification would improve the interrelationship between form and feeding habits in vultures. Moreover, the results of this study reinforce the value of the categorisation system introduced by Kruuk (1967), and expanded by König (1974, 1983), Houston (1988) and Hertel (1994), as it would affect not only the skull morphology but the whole-body architecture.

Generation of a Novel Nkx6-1 Venus Fusion Reporter Mouse Line.

Nkx6-1 is a member of the Nkx family of homeodomain transcription factors (TFs) that regulates motor neuron development, neuron specification and pancreatic endocrine and ß-cell differentiation. To facilitate the isolation and tracking of Nkx6-1-expressing cells, we have generated a novel Nkx6-1 Venus fusion (Nkx6-1-VF) reporter allele. The Nkx6-1-VF knock-in reporter is regulated by endogenous cis-regulatory elements of Nkx6-1 and the fluorescent protein fusion does not interfere with the TF function, as homozygous mice are viable and fertile. The nuclear localization of Nkx6-1-VF protein reflects the endogenous Nkx6-1 protein distribution. During embryonic pancreas development, the reporter protein marks the pancreatic ductal progenitors and the endocrine lineage, but is absent in the exocrine compartment. As expected, the levels of Nkx6-1-VF reporter are upregulated upon ß-cell differentiation during the major wave of endocrinogenesis. In the adult islets of Langerhans, the reporter protein is exclusively found in insulin-secreting ß-cells. Importantly, the Venus reporter activities allow successful tracking of ß-cells in live-cell imaging and their specific isolation by flow sorting. In summary, the generation of the Nkx6-1-VF reporter line reflects the expression pattern and dynamics of the endogenous protein and thus provides a unique tool to study the spatio-temporal expression pattern of this TF during organ development and enables isolation and tracking of Nkx6-1-expressing cells such as pancreatic ß-cells, but also neurons and motor neurons in health and disease.

CD81 marks immature and dedifferentiated pancreatic ß-cells.

OBJECTIVE: Islets of Langerhans contain heterogeneous populations of insulin-producing ß-cells. Surface markers and respective antibodies for isolation, tracking, and analysis are urgently needed to study ß-cell heterogeneity and explore the mechanisms to harness the regenerative potential of immature ß-cells. METHODS: We performed single-cell mRNA profiling of early postnatal mouse islets and re-analyzed several single-cell mRNA sequencing datasets from mouse and human pancreas and islets. We used mouse primary islets, iPSC-derived endocrine cells, Min6 insulinoma, and human EndoC-ßH1 ß-cell lines and performed FAC sorting, Western blotting, and imaging to support and complement the findings from the data analyses. RESULTS: We found that all endocrine cell types expressed the cluster of differentiation 81 (CD81) during pancreas development, but the expression levels of this protein were gradually reduced in ß-cells during postnatal maturation. Single-cell gene expression profiling and high-resolution imaging revealed an immature signature of ß-cells expressing high levels of CD81 (CD81high) compared to a more mature population expressing no or low levels of this protein (CD81low/-). Analysis of ß-cells from different diabetic mouse models and in vitro ß-cell stress assays indicated an upregulation of CD81 expression levels in stressed and dedifferentiated ß-cells. Similarly, CD81 was upregulated and marked stressed human ß-cells in vitro. CONCLUSIONS: We identified CD81 as a novel surface marker that labels immature, stressed, and dedifferentiated ß-cells in the adult mouse and human islets. This novel surface marker will allow us to better study ß-cell heterogeneity in healthy subjects and diabetes progression.

The glucose-dependent insulinotropic polypeptide (GIP) regulates body weight and food intake via CNS-GIPR signaling.

Uncertainty exists as to whether the glucose-dependent insulinotropic polypeptide receptor (GIPR) should be activated or inhibited for the treatment of obesity. Gipr was recently demonstrated in hypothalamic feeding centers, but the physiological relevance of CNS Gipr remains unknown. Here we show that HFD-fed CNS-Gipr KO mice and humanized (h)GIPR knockin mice with CNS-hGIPR deletion show decreased body weight and improved glucose metabolism. In DIO mice, acute central and peripheral administration of acyl-GIP increases cFos neuronal activity in hypothalamic feeding centers, and this coincides with decreased body weight and food intake and improved glucose handling. Chronic central and peripheral administration of acyl-GIP lowers body weight and food intake in wild-type mice, but shows blunted/absent efficacy in CNS-Gipr KO mice. Also, the superior metabolic effect of GLP-1/GIP co-agonism relative to GLP-1 is extinguished in CNS-Gipr KO mice. Our data hence establish a key role of CNS Gipr for control of energy metabolism.

Targeted pharmacological therapy restores ß-cell function for diabetes remission.

Dedifferentiation of insulin-secreting ß cells in the islets of Langerhans has been proposed to be a major mechanism of ß-cell dysfunction. Whether dedifferentiated ß cells can be targeted by pharmacological intervention for diabetes remission, and ways in which this could be accomplished, are unknown as yet. Here we report the use of streptozotocin-induced diabetes to study ß-cell dedifferentiation in mice. Single-cell RNA sequencing (scRNA-seq) of islets identified markers and pathways associated with ß-cell dedifferentiation and dysfunction. Single and combinatorial pharmacology further show that insulin treatment triggers insulin receptor pathway activation in ß cells and restores maturation and function for diabetes remission. Additional ß-cell selective delivery of oestrogen by Glucagon-like peptide-1 (GLP-1-oestrogen conjugate) decreases daily insulin requirements by 60%, triggers oestrogen-specific activation of the endoplasmic-reticulum-associated protein degradation system, and further increases ß-cell survival and regeneration. GLP-1-oestrogen also protects human ß cells against cytokine-induced dysfunction. This study not only describes mechanisms of ß-cell dedifferentiation and regeneration, but also reveals pharmacological entry points to target dedifferentiated ß cells for diabetes remission.

On the problem of biological form.

Embryonic development, which inspired the first theories of biological form, was eventually excluded from the conceptual framework of the Modern Synthesis as irrelevant. A major question during the last decades has centred on understanding whether new advances in developmental biology are compatible with the standard view or whether they compel a new theory. Here, I argue that the answer to this question depends on which concept of morphogenesis is held. Morphogenesis can be conceived as (1) a chemically driven or (2) a mechanically driven process. According to the first option, genetic regulatory networks drive morphogenesis. According to the second, morphogenesis results from an invariant tendency of embryonic tissues to restore changes in mechanical stress. While chemically driven morphogenesis allows an extension of the standard view, mechanically driven morphogenesis would deeply transform it. Which of these hypotheses has wider explanatory power is unknown. At present, the problem of biological form remains unsolved.

ß-Cell Maturation and Identity in Health and Disease.

The exponential increase of patients with diabetes mellitus urges for novel therapeutic strategies to reduce the socioeconomic burden of this disease. The loss or dysfunction of insulin-producing ß-cells, in patients with type 1 and type 2 diabetes respectively, put these cells at the center of the disease initiation and progression. Therefore, major efforts have been taken to restore the ß-cell mass by cell-replacement or regeneration approaches. Implementing novel therapies requires deciphering the developmental mechanisms that generate ß-cells and determine the acquisition of their physiological phenotype. In this review, we summarize the current understanding of the mechanisms that coordinate the postnatal maturation of ß-cells and define their functional identity. Furthermore, we discuss different routes by which ß-cells lose their features and functionality in type 1 and 2 diabetic conditions. We then focus on potential mechanisms to restore the functionality of those ß-cell populations that have lost their functional phenotype. Finally, we discuss the recent progress and remaining challenges facing the generation of functional mature ß-cells from stem cells for cell-replacement therapy for diabetes treatment.

Establishment of a high-resolution 3D modeling system for studying pancreatic epithelial cell biology in vitro.

OBJECTIVE: Translation of basic research from bench-to-bedside relies on a better understanding of similarities and differences between mouse and human cell biology, tissue formation, and organogenesis. Thus, establishing ex vivo modeling systems of mouse and human pancreas development will help not only to understand evolutionary conserved mechanisms of differentiation and morphogenesis but also to understand pathomechanisms of disease and design strategies for tissue engineering. METHODS: Here, we established a simple and reproducible Matrigel-based three-dimensional (3D) cyst culture model system of mouse and human pancreatic progenitors (PPs) to study pancreatic epithelialization and endocrinogenesis ex vivo. In addition, we reanalyzed previously reported single-cell RNA sequencing (scRNA-seq) of mouse and human pancreatic lineages to obtain a comprehensive picture of differential expression of key transcription factors (TFs), cell-cell adhesion molecules and cell polarity components in PPs during endocrinogenesis. RESULTS: We generated mouse and human polarized pancreatic epithelial cysts derived from PPs. This system allowed to monitor establishment of pancreatic epithelial polarity and lumen formation in cellular and sub-cellular resolution in a dynamic time-resolved fashion. Furthermore, both mouse and human pancreatic cysts were able to differentiate towards the endocrine fate. This differentiation system together with scRNA-seq analysis revealed how apical-basal polarity and tight and adherens junctions change during endocrine differentiation. CONCLUSIONS: We have established a simple 3D pancreatic cyst culture system that allows to tempo-spatial resolve cellular and subcellular processes on the mechanistical level, which is otherwise not possible in vivo.

Diagnosis and gestational follow-up in a patient with Herlyn-Werner-Wünderlich syndrome, a case report.

OBJECTIVE: Herlyn-Werner-Wünderlich syndrome (HWW) is a rare congenital malformation of the urogenital tract due to a fusion failure in the Müllerian ducts. This anomaly consists of a didelphus uterus with obstructed hemivagina and sometimes associated with ipsilateral renal agenesis. The treatment of choice is surgical, it consists of a simple procedure of resection of the vaginal septum and drainage of the obstructed hemivagina and retained collections. CASE REPORT: We report the case of a pregnancy in a 37-year-old woman with SHWW without resection of the vaginal septum. CONCLUSIONS: The early detection is important due to the possible associated complications. Women with uterine defects are subject to an increased risk of complications in pregnancy and childbirth. Therefore, each case must be treated individually.

Comprehensive single cell mRNA profiling reveals a detailed roadmap for pancreatic endocrinogenesis.

Deciphering mechanisms of endocrine cell induction, specification and lineage allocation in vivo will provide valuable insights into how the islets of Langerhans are generated. Currently, it is ill defined how endocrine progenitors segregate into different endocrine subtypes during development. Here, we generated a novel neurogenin 3 (Ngn3)-Venus fusion (NVF) reporter mouse line, that closely mirrors the transient endogenous Ngn3 protein expression. To define an in vivo roadmap of endocrinogenesis, we performed single cell RNA sequencing of 36,351 pancreatic epithelial and NVF+ cells during secondary transition. This allowed Ngn3low endocrine progenitors, Ngn3high endocrine precursors, Fev+ endocrine lineage and hormone+ endocrine subtypes to be distinguished and time-resolved, and molecular programs during the step-wise lineage restriction steps to be delineated. Strikingly, we identified 58 novel signature genes that show the same transient expression dynamics as Ngn3 in the 7260 profiled Ngn3-expressing cells. The differential expression of these genes in endocrine precursors associated with their cell-fate allocation towards distinct endocrine cell types. Thus, the generation of an accurately regulated NVF reporter allowed us to temporally resolve endocrine lineage development to provide a fine-grained single cell molecular profile of endocrinogenesis in vivo.