MicroRNAs (miRNAs) are important regulators of gene expression programs in the pancreas; however, little is known about the role of miRNA pathways during endocrine cell specification and maturation during neonatal life. In this study, we deleted Dicer1, an essential RNase for active miRNAs biogenesis, specifically from NGN3+ endocrine progenitor cells. We found that deletion of Dicer1 in endocrine progenitors did not affect the specification of hormone-expressing endocrine cells. However, the islets in the mutant mice in the neonatal period exhibited morphological defects in organization and loss of hormone expression, and the mutant mice subsequently developed diabetes. Dicer1-deficient β-cells lost insulin expression while maintaining the expression of β-cell transcription factors such as Pdx1 and Nkx6.1 early in the postnatal period. Surprisingly, transcriptional profiling showed that that the Dicer1-deficient endocrine cells expressed neuronal genes before the onset of diabetes. The derepression of neuronal genes was associated with a loss in binding of the neuronal transcriptional repressor RE-1-silencing transcription factor to its targets in Dicer1-deficient β-cells. These studies suggest that miRNAs play a critical role in suppressing neuronal genes during the maturation of endocrine cells.

MicroRNAs (miRNAs) are important regulators of gene expression programs in the pancreas; however, little is known about the role of miRNA pathways during endocrine cell specification and maturation during neonatal life. In this study, we deleted Dicer1, an essential RNase for active miRNAs biogenesis, specifically from NGN3+ endocrine progenitor cells. We found that deletion of Dicer1 in endocrine progenitors did not affect the specification of hormone-expressing endocrine cells. However, the islets in the mutant mice in the neonatal period exhibited morphological defects in organization and loss of hormone expression, and the mutant mice subsequently developed diabetes. Dicer1-deficient β-cells lost insulin expression while maintaining the expression of β-cell transcription factors such as Pdx1 and Nkx6.1 early in the postnatal period. Surprisingly, transcriptional profiling showed that that the Dicer1-deficient endocrine cells expressed neuronal genes before the onset of diabetes. The derepression of neuronal genes was associated with a loss in binding of the neuronal transcriptional repressor RE-1-silencing transcription factor to its targets in Dicer1-deficient β-cells. These studies suggest that miRNAs play a critical role in suppressing neuronal genes during the maturation of endocrine cells.

In children, aplastic anemia (AA) is a common complication associated with fulminant hepatic failure (FHF). The objective of this study was to determine whether specific pretransplantation clinical and laboratory characteristics can be used to distinguish between patients with FHF who are at higher risk of developing AA. We performed a retrospective case-control study to evaluate the clinical and laboratory characteristics of those patients who presented with evidence of FHF and eventually developed aplastic anemia. We identified nine patients with AA, and all had the indeterminate form of FHF and underwent liver transplantation (LTx). The AA patients were compared with a control group of 47 patients with indeterminate FHF that underwent transplantation and did not develop AA. We found that males were over-represented in the group of patients that developed AA (p = 0.01). Furthermore, during the pretransplant period, the AA group had a significantly lower white count (p = 0.005), absolute lymphocyte count (p = 0.004), and platelet count (p = 0.019) when compared with controls. We conclude that evidence of early bone marrow dysfunction is apparent before liver transplantation and the development of AA in a subset of patients with the indeterminate form of FHF.

Recent advances in our understanding of the intestinal stem cell niche and the role of key signaling pathways on cell growth and maintenance have allowed the development of fully differentiated epithelial cells in 3D organoids. Stem cell-derived organoids carry significant levels of proteins that are natively expressed in the gut and have important roles in drug transport and metabolism. They are, therefore, particularly relevant to study the gastrointestinal (GI) absorption of oral medications. In addition, organoids have the potential to serve as a robust preclinical model for demonstrating the effectiveness of new drugs more rapidly, with more certainty, and at lower costs compared with live animal studies. Importantly, because they are derived from individuals with different genotypes, environmental risk factors and drug sensitivity profiles, organoids are a highly relevant screening system for personalized therapy in both human and veterinary medicine. Lastly, and in the context of patient-specific congenital diseases, orthotopic transplantation of engineered organoids could repair and/or replace damaged epithelial tissues reported in various GI diseases, such as inflammatory bowel disease, cystic fibrosis, and tuft enteropathy. Ongoing translational research on organoids derived from dogs with naturally occurring digestive disorders has the potential to improve the predictability of preclinical models used for optimizing the therapeutic management of severe chronic enteropathies in human patients.

: Intestinal failure is a rare life-threatening condition that results in the inability to maintain normal growth and hydration status by enteral nutrition alone. Although parenteral nutrition and whole organ allogeneic transplantation have improved the survival of these patients, current therapies are associated with a high risk for morbidity and mortality. Development of methods to propagate adult human intestinal stem cells (ISCs) and pluripotent stem cells raises the possibility of using stem cell-based therapy for patients with monogenic and polygenic forms of intestinal failure. Organoids have demonstrated the capacity to proliferate indefinitely and differentiate into the various cellular lineages of the gut. Genome-editing techniques, including the overexpression of the corrected form of the defective gene, or the use of CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 to selectively correct the monogenic disease-causing variant within the stem cell, make autologous ISC transplantation a feasible approach. However, numerous techniques still need to be further optimized, including more robust ex vivo ISC expansion, native ISC ablation, and engraftment protocols. Large-animal models can to be used to develop such techniques and protocols and to establish the safety of autologous ISC transplantation because outcomes in such models can be extrapolated more readily to humans.The field of intestinal stem cell biology has exploded over the past 5 years with discoveries related to in vivo and in vitro stem cell identity and function. The goal of this review article is to highlight the potential use of these cells to treat various epithelial disorders of the gut and discuss the various roadblocks that will be encountered in the coming years.

The intestinal muscle layers execute various gut wall movements to achieve controlled propulsion and mixing of intestinal content. Engineering intestinal muscle layers with complex contractile function is critical for developing bioartificial intestinal tissue to treat patients with short bowel syndrome. Here, the first demonstration of a living intestinal muscle patch capable of generating three distinct motility patterns and displaying multiple digesta manipulations is reported. Assessment of contractility, cellular morphology, and transcriptome profile reveals that successful generation of the contracting muscle patch relies on both biological factors in a serum-free medium and environmental cues from an elastic electrospun gelatin scaffold. By comparing gene-expression patterns among samples, it is shown that biological factors from the medium strongly affect ion-transport activities, while the scaffold unexpectedly regulates cell-cell communication. Analysis of ligandreceptor interactome identifies scaffold-driven changes in intercellular communication, and 78% of the upregulated ligand-receptor interactions are involved in the development and function of enteric neurons. The discoveries highlight the importance of combining biomolecular and biomaterial approaches for tissue engineering. The living intestinal muscle patch represents a pivotal advancement for building functional replacement intestinal tissue. It offers a more physiological model for studying GI motility and for preclinical drug discovery.

We report a 5-month-old African American male with hepatic steatosis secondary to chronic and exclusive homemade coconut milk formula ingestion. Findings resolved with discontinuation.

Proprotein convertase 1/3 (PC1/3), encoded by the PCSK1 gene, is expressed in neuronal and (entero)endocrine cell types, where it cleaves and hence activates a number of protein precursors that play a key role in energy homeostasis. Loss-of-function mutations in PCSK1 cause a recessive complex endocrinopathy characterized by malabsorptive diarrhea and early-onset obesity. Despite the fact that neonatal malabsorptive diarrhea is observed in all patients, it has remained understudied. The aim of this study was to investigate the enteroendocrine pathologies in a male patient with congenital PCSK1 deficiency carrying the novel homozygous c.1034A>C (p.E345A) mutation. This patient developed malabsorptive diarrhea and metabolic acidosis within the first week of life, but rapid weight gain was observed after total parenteral nutrition, and he displayed high proinsulin levels and low adrenocorticotropin. In vitro analysis showed that the p.E345A mutation in PC1/3 resulted in a (near) normal autocatalytic proPC1/3 processing and only partially impaired PC1/3 secretion, but the processing of a substrate in trans was completely blocked. Immunohistochemical staining did not reveal changes in the proGIP/GIP and proglucagon/GLP-1 ratio in colonic tissue. Hence, we report a novel PCSK1 deficient patient who, despite neonatal malabsorptive diarrhea, showed a normal morphology in the small intestine.

High-throughput DNA sequencing has become a mainstay for the discovery of genomic variants that may cause disease or affect phenotype. A next-generation sequencing pipeline typically identifies thousands of variants in each sample. A particular challenge is the annotation of each variant in a way that is useful to downstream consumers of the data, such as clinical sequencing centers or researchers. These users may require that all data storage and analysis remain on secure local servers to protect patient confidentiality or intellectual property, may have unique and changing needs to draw on a variety of annotation data sets and may prefer not to rely on closed-source applications beyond their control. Here we describe scalable methods for using the plugin capability of the Ensembl Variant Effect Predictor to enrich its basic set of variant annotations with additional data on genes, function, conservation, expression, diseases, pathways and protein structure, and describe an extensible framework for easily adding additional custom data sets.

Congenital diarrhoeal disorders (CDDs) represent an evolving web of rare chronic enteropathies, with a typical onset early in life. In many of these conditions, severe chronic diarrhoea represents the primary clinical manifestation, whereas in others diarrhoea is only a component of a more complex multi-organ or systemic disorder. Typically, within the first days of life, diarrhoea leads to a life-threatening condition highlighted by severe dehydration and serum electrolyte abnormalities. Thus, in the vast majority of cases appropriate therapy must be started immediately to prevent dehydration and long-term, sometimes severe, complications. The number of well-characterized disorders attributed to CDDs has gradually increased over the past several years, and many new genes have been identified and functionally related to CDDs, opening new diagnostic and therapeutic perspectives. Molecular analysis has changed the diagnostic scenario in CDDs, and led to a reduction in invasive and expensive procedures. Major advances have been made in terms of pathogenesis, enabling a better understanding not only of these rare conditions but also of more common diseases mechanisms.