Vesicular sorting controls the polarity of expanding membranes in the C. elegans intestine

Biological tubes consist of polarized epithelial cells with apical membranes building the central lumen and basolateral membranes contacting adjacent cells or the extracellular matrix. Cellular polarity requires distinct inputs from outside the cell, e.g., the matrix, inside the cell, e.g., vesicular trafficking and the plasma membrane and its junctions.1 Many highly conserved polarity cues have been identified, but their integration during the complex process of polarized tissue and organ morphogenesis is not well understood. It is assumed that plasma-membrane-associated polarity determinants, such as the partitioning-defective (PAR) complex, define plasma membrane domain identities, whereas vesicular trafficking delivers membrane components to these domains, but lacks the ability to define them. In vitro studies on lumenal membrane biogenesis in mammalian cell lines now indicate that trafficking could contribute to defining membrane domains by targeting the polarity determinants, e.g., the PARs, themselves.2 This possibility suggests a mechanism for PARs’ asymmetric distribution on membranes and places vesicle-associated polarity cues upstream of membrane-associated polarity determinants. In such an upstream position, trafficking might even direct multiple membrane components, not only polarity determinants, an original concept of polarized plasma membrane biogenesis3,4that was largely abandoned due to the failure to identify a molecularly defined intrinsic vesicular sorting mechanism. Our two recent studies on C. elegans intestinal tubulogenesis reveal that glycosphingolipids (GSLs) and the well-recognized vesicle components clathrin and its AP-1 adaptor are required for targeting multiple apical molecules, including polarity regulators, to the expanding apical/lumenal membrane.5,6 These findings support GSLs’ long-proposed role in in vivo polarized epithelial membrane biogenesis and development and identify a novel function in apical polarity for classical post-Golgi vesicle components. They are also compatible with a vesicle-intrinsic sorting mechanism during membrane biogenesis and suggest a model for how vesicles could acquire apical directionality during the assembly of the functionally critical polarized lumenal surfaces of epithelial tubes

Extracellular Vesicles: A Potential Novel Regulator of Obesity and Its Associated Complications

Childhood obesity continues to be a major public health concern. Obesity causes various metabolic complications, including insulin resistance, type 2 diabetes mellitus (T2DM), non-alcoholic fatty liver disease (NAFLD), dyslipidemia, and cardiovascular disease. However, currently, we have a limited understanding of the pathophysiology in the development of these processes. Extracellular vesicles (EVs) are nano-sized vesicles secreted by different cell types that travel to various organ systems carrying molecular and genetic information. These vesicles have been proposed as a novel intercellular communication mode in systemic metabolic regulation and in several pathophysiologic processes. In particular, recent studies indicate that EVs play a critical role in the pathogenesis of obesity and its metabolic complications. In this study, we reviewed the current literature that supports the role of EVs in the regulation of metabolic homeostasis and pathogenesis of obesity and its associated metabolic complications, with a short discussion about future directions in the EV research field

Two Case Reports of Newly Diagnosed Crohn’s Disease after COVID-19 in Pediatric Patients

Since the coronavirus disease 2019 (COVID-19) outbreak caused by the severe acute respiratory syndrome-coronavirus-2 virus (SARS-CoV-2), various complications have been reported. Although most COVID-19 cases exhibited flu-like symptoms, COVID-19 may dysregulate the immune response and promote overwhelming levels of inflammation in some patients. Inflammatory bowel disease (IBD) is caused by dysregulated or inappropriate immune responses to environmental factors in a genetically susceptible host, and a SARS-CoV-2 infection may act as a possible cause of IBD. This paper describes two pediatric patients who developed Crohn’s disease following a SARS-CoV-2 infection. They were previously healthy before the SARS-CoV-2 infection. On the other hand, they started to develop fever and gastrointestinal symptoms several weeks after recovery from the infection. They were diagnosed with Crohn’s disease by imaging and endoscopic studies, and their symptoms improved after treatment with steroids and azathioprine. This paper suggests that a SARS-CoV-2 infection may trigger IBD in predisposed patients

Factors Associated With Achieving Target A1C in Children and Adolescents With Type 1 Diabetes: Findings From the T1D Exchange Quality Improvement Collaborative.

The optimal care of type 1 diabetes involves consistent glycemic management to avoid short- and long-term complications. However, despite advancements in diabetes technology and standards, achieving adequate glycemic levels in children and adolescents remains a challenge. This study aimed to identify factors associated with achieving the recommended A1C target of <7% from the United States-based multicenter T1D Exchange Quality Improvement Collaborative cohort, including 25,383 children and adolescents living with type 1 diabetes