Controlling human stem cell-derived islet composition using magnetic sorting.

Stem cell-derived islets (SC-islets) consists of multiple hormone-producing cell types and offer a promising therapeutic avenue for treating type 1 diabetes (T1D). Currently, the composition of cell types generated within these SC-islets currently cannot be controlled via soluble factors during this differentiation process and consist of off-target cell types. In this study, we devised a magnetic-activated cell sorting (MACS) protocol to enrich SC-islets for CD49a, a marker associated with functional insulin-producing β cells.

Depolymerizing F-actin accelerates the exit from pluripotency to enhance stem cell-derived islet differentiation.

In this study, we demonstrate that cytoskeletal state at the onset of directed differentiation is critical for the specification of human pluripotent stem cells (hPSCs) to all three germ layers. In particular, a polymerized actin cytoskeleton facilitates directed ectoderm differentiation, while depolymerizing F-actin promotes mesendoderm lineages. Applying this concept to a stem cell-derived islet (SC-islet) differentiation protocol, we show that depolymerizing F-actin with latrunculin A (latA) during the first 24 hours of definitive endoderm formation facilitates rapid exit from pluripotency and alters Activin/Nodal, BMP, JNK-JUN, and WNT pathway signaling dynamics.

Identification of unique cell type responses in pancreatic islets to stress.

Diabetes involves the death or dysfunction of pancreatic β-cells. Analysis of bulk sequencing from human samples and studies using in vitro and in vivo models suggest that endoplasmic reticulum and inflammatory signaling play an important role in diabetes progression. To better characterize cell type-specific stress response, we perform multiplexed single-cell RNA sequencing to define the transcriptional signature of primary human islet cells exposed to endoplasmic reticulum and inflammatory stress.

Single-nucleus multi-omics of human stem cell-derived islets identifies deficiencies in lineage specification.

Insulin-producing β cells created from human pluripotent stem cells have potential as a therapy for insulin-dependent diabetes, but human pluripotent stem cell-derived islets (SC-islets) still differ from their in vivo counterparts. To better understand the state of cell types within SC-islets and identify lineage specification deficiencies, we used single-nucleus multi-omic sequencing to analyse chromatin accessibility and transcriptional profiles of SC-islets and primary human islets. Here we provide an analysis that enabled the derivation of gene lists and activity for identifying each SC-islet cell type compared with primary islets.

Microfluidic device facilitates in vitro modeling of human neonatal necrotizing enterocolitis-on-a-chip.

Necrotizing enterocolitis (NEC) is a deadly gastrointestinal disease of premature infants that is associated with an exaggerated inflammatory response, dysbiosis of the gut microbiome, decreased epithelial cell proliferation, and gut barrier disruption. We describe an in vitro model of the human neonatal small intestinal epithelium (Neonatal-Intestine-on-a-Chip) that mimics key features of intestinal physiology. This model utilizes intestinal enteroids grown from surgically harvested intestinal tissue from premature infants and cocultured with human intestinal microvascular endothelial cells within a microfluidic device.

Differential Function and Maturation of Human Stem Cell-Derived Islets After Transplantation.

Insulin-producing stem cell-derived islets (SC-islets) provide a virtually unlimited cell source for diabetes cell replacement therapy. While SC-islets are less functional when first differentiated in vitro compared to isolated cadaveric islets, transplantation into mice has been shown to increase their maturation. To understand the effects of transplantation on maturation and function of SC-islets, we examined the effects of cell dose, transplantation strategy, and diabetic state in immunocompromised mice.

Loss of SNORA73 reprograms cellular metabolism and protects against steatohepatitis.

Dyslipidemia and resulting lipotoxicity are pathologic signatures of metabolic syndrome and type 2 diabetes. Excess lipid causes cell dysfunction and induces cell death through pleiotropic mechanisms that link to oxidative stress. However, pathways that regulate the response to metabolic stress are not well understood.

Validation of Trifluoromethylphenyl Diazirine Cholesterol Analogues As Cholesterol Mimetics and Photolabeling Reagents.

Aliphatic diazirine analogues of cholesterol have been used previously to elaborate the cholesterol proteome and identify cholesterol binding sites on proteins. Cholesterol analogues containing the trifluoromethylphenyl diazirine (TPD) group have not been reported. Both classes of diazirines have been prepared for neurosteroid photolabeling studies and their combined use provided information that was not obtainable with either diazirine class alone.

Interleukin-22 signaling attenuates necrotizing enterocolitis by promoting epithelial cell regeneration.

Necrotizing enterocolitis (NEC) is a deadly intestinal inflammatory disorder that primarily affects premature infants and lacks adequate therapeutics. Interleukin (IL)-22 plays a critical role in gut barrier maintenance, promoting epithelial regeneration, and controlling intestinal inflammation in adult animal models. However, the importance of IL-22 signaling in neonates during NEC remains unknown.

Whole exome sequencing and functional characterization increase diagnostic yield in siblings with a 46, XY difference of sexual development (DSD).

Pathogenic biallelic variants in HSD17B3 result in 17β-hydroxysteroid dehydrogenase 3 (17β-HSD3) deficiency, variable disruption of testosterone production, and phenotypic diversity among 46, XY individuals with differences of sexual development (DSDs). We performed quad whole exome sequencing (WES) on two male siblings with microphallus, perineal hypospadias, and bifid scrotum and their unaffected parents. Both male siblings were compound heterozygous for a rare pathogenic HSD17B3 variant (c.

Indole-3-Carbinol-Dependent Aryl Hydrocarbon Receptor Signaling Attenuates the Inflammatory Response in Experimental Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) causes significant morbidity and mortality in premature infants; therefore, the identification of therapeutic and preventative strategies against NEC remains a high priority. The ligand-dependent transcription factor aryl hydrocarbon receptor (AhR) is well known to contribute to the regulation of intestinal microbial communities and amelioration of intestinal inflammation. However, the role of AhR signaling in NEC is unclear.

Monitoring the itinerary of lysosomal cholesterol in Niemann-Pick Type C1-deficient cells after cyclodextrin treatment.

Niemann-Pick disease type C (NPC) disease is a lipid-storage disorder that is caused by mutations in the genes encoding NPC proteins and results in lysosomal cholesterol accumulation. 2-Hydroxypropyl-β-cyclodextrin (CD) has been shown to reduce lysosomal cholesterol levels and enhance sterol homeostatic responses, but CD's mechanism of action remains unknown. Recent work provides evidence that CD stimulates lysosomal exocytosis, raising the possibility that lysosomal cholesterol is released in exosomes.

2-Hydroxypropyl-β-cyclodextrin is the active component in a triple combination formulation for treatment of Niemann-Pick C1 disease.

Niemann-Pick type C1 (NPC1) disease is a fatal neurovisceral disease for which there are no FDA approved treatments, though cyclodextrin (HPβCD) slows disease progression in preclinical models and in an early phase clinical trial. Our goal was to evaluate the mechanism of action of a previously described combination-therapy, Triple Combination Formulation (TCF) - comprised of the histone deacetylase inhibitor (HDACi) vorinostat/HPβCD/PEG - shown to prolong survival in Npc1 mice. In these studies, TCF's benefit was attributed to enhanced vorinostat pharmacokinetics (PK).

Synthesis and characterization of diazirine alkyne probes for the study of intracellular cholesterol trafficking.

Cholesterol is an essential structural component of cellular membranes and precursor molecule for oxysterol, bile acid, and hormone synthesis. The study of intracellular cholesterol trafficking pathways has been limited in part due to a lack of suitable cholesterol analogues. Herein, we developed three novel diazirine alkyne cholesterol probes: LKM38, KK174, and KK175.

19q13.12 microdeletion syndrome fibroblasts display abnormal storage of cholesterol and sphingolipids in the endo-lysosomal system.

Microdeletions in 19q12q13.12 cause a rare and complex haploinsufficiency syndrome characterized by intellectual deficiency, developmental delays, and neurological movement disorders. Variability in the size and interval of the deletions makes it difficult to attribute the complex clinical phenotype of this syndrome to an underlying gene(s).

Development of a bile acid-based newborn screen for Niemann-Pick disease type C.

Niemann-Pick disease type C (NPC) is a fatal, neurodegenerative, cholesterol storage disorder. With new therapeutics in clinical trials, it is imperative to improve diagnostics and facilitate early intervention. We used metabolomic profiling to identify potential markers and discovered three unknown bile acids that were increased in plasma from NPC but not control subjects.

A novel intrinsically fluorescent probe for study of uptake and trafficking of 25-hydroxycholesterol.

Cholesterol homeostasis is regulated not only by cholesterol, but also by oxygenated cholesterol species, referred to as oxysterols. Side-chain oxysterols, such as 25-hydroxycholesterol (25-HC), regulate cholesterol homeostasis through feedback inhibition and feed-forward activation of transcriptional pathways that govern cholesterol synthesis, uptake, and elimination, as well as through direct nongenomic actions that modulate cholesterol accessibility in membranes. Elucidating the cellular distribution of 25-HC is required to understand its biological activity at the molecular level.

snoRNA U17 regulates cellular cholesterol trafficking.

Cholesterol is required for the growth and viability of mammalian cells and is an obligate precursor for steroid hormone synthesis. Using a loss-of-function screen for mutants with defects in intracellular cholesterol trafficking, a Chinese hamster ovary cell mutant with haploinsufficiency of the U17 snoRNA was isolated. U17 is an H/ACA orphan snoRNA, for which a function other than ribosomal processing has not previously been identified.

Side-chain oxysterols modulate cholesterol accessibility through membrane remodeling.

Side-chain oxysterols, such as 25-hydroxycholesterol (25-HC), are key regulators of cholesterol homeostasis. New evidence suggests that the alteration of membrane structure by 25-HC contributes to its regulatory effects. We have examined the role of oxysterol membrane effects on cholesterol accessibility within the membrane using perfringolysin O (PFO), a cholesterol-dependent cytolysin that selectively binds accessible cholesterol, as a sensor of membrane cholesterol accessibility.

Box C/D small nucleolar RNA (snoRNA) U60 regulates intracellular cholesterol trafficking.

Mobilization of plasma membrane (PM) cholesterol to the endoplasmic reticulum is essential for cellular cholesterol homeostasis. The mechanisms regulating this retrograde, intermembrane cholesterol transfer are not well understood. Because mutant cells with defects in PM to endoplasmic reticulum cholesterol trafficking can be isolated on the basis of resistance to amphotericin B, we conducted an amphotericin B loss-of-function screen in Chinese hamster ovary (CHO) cells using insertional mutagenesis to identify genes that regulate this trafficking mechanism.

Tumoral calcinosis: a dental literature review and case report.

Unlabelled: Tumoral calcinosis (TC) is a rare familial disease characterized by abnormal peri-articular calcification in affected joints, without any associated renal, metabolic or collagen vascular disease. It is characterized by usual hyperphosphataemia with normal serum calcium and alkaline phosphatase values. There are only a few reported cases ofTC patients with dental findings.

Cholesterol oxidation products are sensitive and specific blood-based biomarkers for Niemann-Pick C1 disease.

Niemann-Pick type C1 (NPC1) disease is a rare progressive neurodegenerative disorder characterized by accumulation of cholesterol in the endolysosomes. Previous studies implicating oxidative stress in NPC1 disease pathogenesis raised the possibility that nonenzymatic formation of cholesterol oxidation products could serve as disease biomarkers. We measured these metabolites in the plasma and tissues of the Npc1(-/-) mouse model and found several cholesterol oxidation products that were elevated in Npc1(-/-) mice, were detectable before the onset of symptoms, and were associated with disease progression.

Common things are common: a case series of oral foreign bodies in paediatric patients.

Reports of foreign bodies in the oral cavity are few in number. Three cases of children of varying ages, presenting with oral foreign bodies, and their subsequent diagnosis and management, are described. The importance of considering foreign bodies, as part of a differential diagnosis in paediatric patients, where aetiology is uncertain and clinical appearance is unusual, is highlighted.