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The interplay between lipid droplets (LDs) and endosomes remains unknown. Here, we screen and synthesize AP1-coumarin, an LD-specific probe, by conjugating a fluorescent dye coumarin to a triazine compound AP1. AP1-coumarin labels all stages of LDs in live cells and markedly induces the accumulation of enlarged RAB5-RAB7 double-positive intermediate endosomes. The AP1-coumarin-labeled LDs contact these intermediate endosomes, with some LDs even being engulfed in them. When LD biogenesis is inhibited, the ability of AP1-coumarin to label LDs is markedly reduced, and the accumulation of enlarged intermediate endosomes is abolished. Moreover, blocking the biogenesis of LDs decreases the number of late endosomes while increasing the number of early endosomes and inhibits the endosomal trafficking of low-density lipoprotein (LDL) and transferrin. Correspondingly, interference with RAB5 or RAB7, either through knockdown or using dominant-negative mutants, inhibits LD catabolism, whereas the expression of a RAB7 constitutively active mutant accelerates LD catabolism. Additionally, CCZ1 knockdown not only induces the accumulation of intermediate endosomes but also inhibits LD catabolism. These results collectively suggest that LDs and endosomes interact and influence each other’s functions, and endosomal trafficking participates in the catabolic process of LDs to maintain lipid homeostasis. Lipid droplets (LDs) and endosomes play crucial roles in cellular processes, yet their interplay is poorly understood. Here, the authors develop an LD-specific probe, AP1-coumarin, and reveal dynamic interactions between LDs and endosomes, regulating lipid homeostasis.

Patients with cirrhosis have a high prevalence of peptic ulcer disease, which places them at increased risk for complications such as perforation. We report the case of a patient with decompensated cirrhosis who developed a duodenal ulcer perforation following an upper endoscopy for variceal screening. Due to poor surgical candidacy, he was managed conservatively through antibiotics, percutaneous drains, and endoscopic placement of a fully covered self‐expandable metal stent (fcSEMS). With no established guidelines on managing duodenal perforations in cirrhotic patients, this case demonstrates a successful outcome with a nonoperative approach that can be considered when definitive surgical intervention is not feasible.

Background Retinoic acid(RA), an embryonic morphogen, regulates cell differentiation. Endocytosis regulates receptor signaling that governs such RA-directed cellular processes. Vacuolin-1 is a small molecule that disrupts endocytosis, motivating interest in its effect on RA-induced differentiation/arrest. In HL-60 myeloblastic-leukemia cells, RA causes differentiation evidenced by a progression of cell-surface and functional markers, CD38, CD11b, and finally reactive oxygen species(ROS) production and G1/0 cell cycle arrest in mature cells. Results We found that Vacuolin-1 enhanced RA-induced CD11b, ROS and G1/0 arrest, albeit not CD38. Enhanced CD11b expression was associated with enhanced activation of Focal Adhesion Kinase(FAK). Adding vacuolin-1 enhanced RA-induced tyrosine phosphorylation of FAK, Src Family Kinases(SFKs), and the adaptor protein, SLP-76, expression of which is known to drive RA-induced differentiation. Depleting CD11b cripples late stages of progressive myeloid differentiation, namely G1/0 arrest and inducible ROS production, but not expression of CD38. Loss of NUMB, a protein that supports early endosome maturation, affected RA-induced ROS and G1/0 arrest, but not CD38 expression. Conclusion Hence there appears to be a novel CD11b/FAK/LYN/SLP-76 axis subject to endosome regulation which contributes to later stages of RA-induced differentiation. The effects of vacuolin-1 thus suggest a model where RA-induced differentiation consists of progressive stages driven by expression of sequentially-induced receptors.

Introduction: Clinically significant serrated lesions (SL) may contribute to colon cancers (AJG 2012;107:1315-30) through a pathway unrelated to the adenoma-cancer sequence (CGH 2016;14:105659). These often subtle and non-polypoid lesions include sessile serrated adenomas/polyps, traditional serrated adenomas and hyperplastic polyps in the proximal colon, and missed lesions may account for interval cancers in proximal colon. Table 1 shows the impact of various combinations of cap (C), water exchange (WE) and chromoendoscopy with indigo carmine added to water (CE) on detection rate (DR) of various lesions (adenomas, serrated lesions) in proximal colon. We hypothesize that cap-assisted total water with chromoendoscopy (CATWCE) can further improve proximal adenoma detection (ADR) and clinically significant serrated lesions detection rate (SLDR) in screening and surveillance colonoscopy. Methods: Retrospective analysis of performance improvement observations in two consecutive series. Colonoscopy was performed with a transparent cap attached to tip of high definition colonoscope (Olympus PCF-H190L). Examination with CATW was performed with plain water and CATWCE used a 0.002 % indigocarmine solution. Air button was turned off. Water was infused and exchanged to remove debris on scope insertion until cecum was reached. Air pockets were suctioned. Water was used on scope withdrawal to facilitate examination and underwater polypectomy with forceps, cold or hot snares. Water was suctioned at dependent locations and tallied. No air was used for either method. Results: A total of 250 patients (125 per group) were included. Patients demographics (age, BMI) were comparable (Table 2). There were more patients for surveillance in CATW and screening in CATWCE. Total amount of water infused/suctioned were comparable. Cecal intubation time and success rate were comparable but withdrawal time was longer for CATWCE. Compared with CATW, CATWCE has significantly higher proximal < 5 mm ADR (67% vs 60% respectively, p< 0.05), and proximal SLDR (33% vs 17%, respectively, p< 0.05) Conclusion: Limitations: Retrospective analysis of non-randomized consecutive series of Veterans, single operator. Conclusion: Combined cap-assisted total water and chromoendoscopy (CATWCE) significantly improved proximal (< 5 mm) ADR and proximal SLDR in screening and surveillance colonoscopy. The role of CATWCE in colorectal cancer prevention including interval cancers deserves further evaluation in a prospective RCT

Blood transfusion practices for acute upper gastrointestinal hemorrhage have changed over time. Restrictive strategies, which gave way to more liberal approaches for the greater part of the 20th century, have again gained traction as emerging research suggests restricting transfusion is associated with similar, or possibly better outcomes in UGI bleeding. In a large, retrospective cohort study from an integrated health care system in Taiwan, Chen, et al., report the association between early blood transfusion and clinical outcomes in patients presenting to the emergency department with UGI bleeding, and these findings are discussed in the context of current knowledge and practice.

In this study, we present an effective model All-Trans Retinoic Acid (ATRA)-induced differentiation of HL-60 cells. The model describes reinforcing feedback between an ATRA-inducible signalsome complex involving many proteins including Vav1, a guanine nucleotide exchange factor, and the activation of the mitogen activated protein kinase (MAPK) cascade. We decomposed the effective model into three modules; a signal initiation module that sensed and transformed an ATRA signal into program activation signals; a signal integration module that controlled the expression of upstream transcription factors; and a phenotype module which encoded the expression of functional differentiation markers from the ATRA-inducible transcription factors. We identified an ensemble of effective model parameters using measurements taken from ATRA-induced HL-60 cells. Using these parameters, model analysis predicted that MAPK activation was bistable as a function of ATRA exposure. Conformational experiments supported ATRA-induced bistability. Additionally, the model captured intermediate and phenotypic gene expression data. Knockout analysis suggested Gfi-1 and PPARg were critical to the ATRAinduced differentiation program. These findings, combined with other literature evidence, suggested that reinforcing feedback is central to hyperactive signaling in a diversity of cell fate programs.

Directed differentiation of embryonic stem cells indicates that mesodermal lineages in the mammalian heart (cardiac, endothelial, and smooth muscle cells) develop from a common, multipotent cardiovascular precursor. To isolate and characterize the lineage potential of a resident pool of cardiovascular progenitor cells (CPcs), we developed BAC transgenic mice in which enhanced green fluorescent protein (EGFP) is placed under control of the c-kit locus (c-kitBAC-EGFP mice). Discrete c-kit-EGFP⁺ cells were observed at different stages of differentiation in embryonic hearts, increasing in number to a maximum at about postnatal day (PN) 2; thereafter, EGFP⁺ cells declined and were rarely observed in the adult heart. EGFP⁺ cells purified from PN 0-5 hearts were nestin⁺ and expanded in culture; 67% of cells were fluorescent after 9 days. Purified cells differentiated into endothelial, cardiac, and smooth muscle cells, and differentiation could be directed by specific growth factors. CPc-derived cardiac myocytes displayed rhythmic beating and action potentials characteristic of multiple cardiac cell types, similar to ES cell-derived cardiomyocytes. Single-cell dilution studies confirmed the potential of individual CPcs to form all 3 cardiovascular lineages. In adult hearts, cryoablation resulted in c-kit-EGFP⁺ expression, peaking 7 days postcryolesion. Expression occurred in endothelial and smooth muscle cells in the revascularizing infarct, and in terminally differentiated cardiomyocytes in the border zone surrounding the infarct. Thus, c-kit expression marks CPc in the neonatal heart that are capable of directed differentiation in vitro; however, c-kit expression in cardiomyocytes in the adult heart after injury does not identify cardiac myogenesis.

6-Formylindolo(3,2-b)carbazole (FICZ) is a photoproduct of tryptophan and an endogenous high affinity ligand for aryl hydrocarbon receptor (AhR). It was previously reported that, in patient-derived HL-60 myeloblastic leukemia cells, retinoic acid (RA)-induced differentiation is driven by a signalsome containing c-Cbl and AhR. FICZ enhances RA-induced differentiation, assessed by expression of the membrane differentiation markers CD38 and CD11b, cell cycle arrest and the functional differentiation marker, inducible oxidative metabolism. Moreover, FICZ augments the expression of a number of the members of the RA-induced signalsome, such as c-Cbl, Vav1, Slp76, PI3K, and the Src family kinases Fgr and Lyn. Pursuing the molecular signaling responsible for RA-induced differentiation, we characterized, using FRET and clustering analysis, associations of key molecules thought to drive differentiation. Here we report that, assayed by FRET, AhR interacts with c-Cbl upon FICZ plus RA-induced differentiation, whereas AhR constitutively interacts with Cbl-b. Moreover, correlation analysis based on the flow cytometric assessment of differentiation markers and western blot detection of signaling factors reveal that Cbl-b, p-p38α and pT390-GSK3β, are not correlated with other known RA-induced signaling components or with a phenotypic outcome. We note that FICZ plus RA elicited signaling responses that were not typical of RA alone, but may represent alternative differentiation-driving pathways. In clusters of signaling molecules seminal to cell differentiation, FICZ co-administered with RA augments type and intensity of the dynamic changes induced by RA. Our data suggest relevance for FICZ in differentiation-induction therapy. The mechanism of action includes modulation of a SFK and MAPK centered signalsome and c-Cbl-AhR association.