Targeting developmental regulators of zebrafish exocrine pancreas as a therapeutic approach in human pancreatic cancer.
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ABSTRACT:
SUBMITTER: Yee NS
PROVIDER: S-EPMC3509454 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:AIM:The purpose of this study was to clarify whether fatty pancreas might lead to impaired pancreatic endocrine or exocrine function. MATERIAL AND METHODS:The study involved 109 participants who had undergone the glucagon stimulation test and N-benzoyl-L-tyros-p-amino benzoic acid (BT-PABA) test to assess pancreatic function as well as unenhanced abdominal computed tomography (CT). Pancreatic endocrine impairment was defined as ΔC peptide immunoreactivity less than 2 [mmol/L] in the glucagon stimulation test, and pancreatic exocrine impairment was defined as a urinary PABA excretion rate less than 70% on the BT-PABA test. We defined as the mean CT value of pancreas / CT value of spleen (P/S ratio) as a marker to assess fatty pancreas. We analyzed the association between fatty pancreas and pancreatic impairment using the logistic regression model. The odds ratio (OR) is shown per 0.1 unit. RESULTS:Pancreatic endocrine function was impaired in 33.0% of the participants, and 56.9% of those were regarded as having pancreatic exocrine impairment. The P/S ratio was significantly correlated with pancreatic endocrine impairment in univariate analysis (OR = 0.61, 95% confidence interval (CI) = 0.43-0.83, P = 0.0013) and multivariate analysis (OR = 0.38, 95% CI = 0.22-0.61, P < .0001) for all participants. Similar significant relationships were observed in both univariate (OR = 0.70, 95% CI = 0.49-0.99, P = 0.04) and multivariate (OR = 0.39, 95% CI = 0.21-0.66, P = 0.0002) analyses for the participants without diabetes (n = 93). The amount of pancreatic fat was not associated with exocrine impairment in univariate analysis (OR = 0.80, 95% CI = 0.59-1.06, P = 0.12). CONCLUSION:Fatty pancreas was associated with pancreatic endocrine impairment but did not have a clear relationship with pancreatic exocrine impairment.
| S-EPMC6301765 | biostudies-literature
Project description:Although the cell of origin for pancreatic cancer remains unknown, prior studies have suggested that pancreatic neoplasia may be initiated in progenitor-like cells. To examine the effects of oncogene activation within the pancreatic progenitor pool, we devised a system for real-time visualization of both normal and oncogenic KRAS-expressing pancreatic progenitor cells in living zebrafish embryos.By using BAC transgenes under the regulation of ptf1a regulatory elements, we expressed either extended green fluorescent protein (eGFP) alone or eGFP fused to oncogenic KRAS in developing zebrafish pancreas.After their initial specification, normal eGFP-labeled pancreatic progenitor cells were observed to actively migrate away from the forming endodermal gut tube, and subsequently underwent characteristic exocrine differentiation. In contrast, pancreatic progenitor cells expressing oncogenic KRAS underwent normal specification and migration, but failed to differentiate. This block in differentiation resulted in the abnormal persistence of an undifferentiated progenitor pool, and was associated with the subsequent formation of invasive pancreatic cancer. These tumors showed several features in common with the human disease, including evidence of abnormal Hedgehog pathway activation.These results provide a unique view of the tumor-initiating effects of oncogenic KRAS in a living vertebrate organism, and suggest that zebrafish models of pancreatic cancer may prove useful in advancing our understanding of the human disease.
| S-EPMC2654247 | biostudies-literature
Project description:The gene encoding the E3 ubiquitin ligase Ligand of Numb protein-X (Lnx)2a is expressed in the ventral-anterior pancreatic bud of zebrafish embryos in addition to its expression in the brain. Knockdown of Lnx2a by using an exon 2/intron 2 splice morpholino resulted in specific inhibition of the differentiation of ventral bud derived exocrine cell types, with little effect on endocrine cell types. A frame shifting null mutation in lnx2a did not mimic this phenotype, but a mutation that removed the exon 2 splice donor site did. We found that Lnx2b functions in a redundant manner with its paralog Lnx2a. Inhibition of lnx2a exon 2/3 splicing causes exon 2 skipping and leads to the production of an N-truncated protein that acts as an interfering molecule. Thus, the phenotype characterized by inhibition of exocrine cell differentiation requires inactivation of both Lnx2a and Lnx2b. Human LNX1 is known to destabilize Numb, and we show that inhibition of Numb expression rescues the Lnx2a/b-deficient phenotype. Further, Lnx2a/b inhibition leads to a reduction in the number of Notch active cells in the pancreas. We suggest that Lnx2a/b function to fine tune the regulation of Notch through Numb in the differentiation of cell types in the early zebrafish pancreas. Further, the complex relationships among genotype, phenotype, and morpholino effect in this case may be instructive in the ongoing consideration of morpholino use.
| S-EPMC4603503 | biostudies-literature
Project description:ObjectiveFatty infiltration of the pancreas is a dominating feature in cystic fibrosis (CF). We evaluate the association between pancreatic fat content assessed by Dixon magnetic resonance imaging (MRI), pancreatic echogenicity at ultrasonography (US) and exocrine function in CF patients and healthy controls (HC).Material and methodsTransabdominal US, pancreatic Dixon-MRI and diffusion-weighted imaging (DWI) were performed in 21 CF patients and 15 HCs. Exocrine function was assessed by endoscopic secretin test and fecal elastase.ResultsCF patients were grouped according to exocrine pancreatic function as subjects with normal (CFS: n = 11) or reduced (CFI: n = 10) function. Among CFI 90% (9/10) had visual hyperechogenicity. CFI also had increased echo-level values (p<0.05 vs others). All CFI (10/10) had markedly increased pancreatic fat content estimated by MRI compared to sufficient groups, p<0.001). Among CFS patients and HC, 27% (3/11) and 33% (5/15), respectively, had hyperechoic pancreas. However, all these had low pancreatic fat-content at MRI compared to CFI. In CFI, pancreatic fat content was correlated to ADC (r = -0.93, p<0.001).ConclusionPancreas insufficient CF patients exhibit severe pancreatic fatty-infiltration at MRI and hyperechoic pancreas at US. Pancreas hyperechogenicity in pancreatic sufficient subjects does not co-exist with fatty infiltration at MRI. MRI evaluates pancreatic fatty infiltration more accurately than US and fat infiltration estimated by MRI outperforms sonographic hyper-echogenicity as a marker for exocrine pancreatic failure in CF.
| S-EPMC6062060 | biostudies-literature
Project description:Transcription factor mediated lineage reprogramming of human pancreatic exocrine tissue could conceivably provide an unlimited supply of islets for transplantation in the treatment of diabetes. Exocrine tissue can be efficiently reprogrammed to islet-like cells using a cocktail of transcription factors: Pdx1, Ngn3, MafA and Pax4 in combination with growth factors. We show here that overexpression of exogenous Pax4 in combination with suppression of the endogenous transcription factor ARX considerably enhances the production of functional insulin-secreting β-like cells with concomitant suppression of α-cells. The efficiency was further increased by culture on laminin-coated plates in media containing low glucose concentrations. Immunocytochemistry revealed that reprogrammed cultures were composed of ~45% islet-like clusters comprising >80% monohormonal insulin+ cells. The resultant β-like cells expressed insulin protein levels at ~15-30% of that in adult human islets, efficiently processed proinsulin and packaged insulin into secretory granules, exhibited glucose responsive insulin secretion, and had an immediate and prolonged effect in normalising blood glucose levels upon transplantation into diabetic mice. We estimate that approximately 3 billion of these cells would have an immediate therapeutic effect following engraftment in type 1 diabetes patients and that one pancreas would provide sufficient tissue for numerous transplants.
| S-EPMC4887015 | biostudies-literature
Project description:Pancreatic stellate cells (PaSCs) are non-endocrine, mesenchymal-like cells that reside within the peri-pancreatic tissue of the rodent and human pancreas. PaSCs regulate extracellular matrix (ECM) turnover in maintaining the integrity of pancreatic tissue architecture. Although there is evidence indicating that PaSCs are involved in islet cell survival and function, its role in islet cell differentiation during human pancreatic development remains unclear. The present study examines the expression pattern and functional role of PaSCs in islet cell differentiation of the developing human pancreas from late 1st to 2nd trimester of pregnancy. The presence of PaSCs in human pancreata (8-22 weeks of fetal age) was characterized by ultrastructural, immunohistological, quantitative RT-PCR and western blotting approaches. Using human fetal PaSCs derived from pancreata at 14-16 weeks, freshly isolated human fetal islet-epithelial cell clusters (hIECCs) were co-cultured with active or inactive PaSCs in vitro. Ultrastructural and immunofluorescence analysis demonstrated a population of PaSCs near ducts and newly formed islets that appeared to make complex cell-cell dendritic-like contacts. A small subset of PaSCs co-localized with pancreatic progenitor-associated transcription factors (PDX1, SOX9, and NKX6-1). PaSCs were highly proliferative, with significantly higher mRNA and protein levels of PaSC markers (desmin, αSMA) during the 1st trimester of pregnancy compared to the 2nd trimester. Isolated human fetal PaSCs were identified by expression of stellate cell markers and ECM. Suppression of PaSC activation, using all-trans retinoic acid (ATRA), resulted in reduced PaSC proliferation and ECM proteins. Co-culture of hIECCs, directly on PaSCs or indirectly using Millicell® Inserts or using PaSC-conditioned medium, resulted in a reduction the number of insulin+ cells but a significant increase in the number of amylase+ cells. Suppression of PaSC activation or Notch activity during the co-culture resulted in an increase in beta-cell differentiation. This study determined that PaSCs, abundant during the 1st trimester of pancreatic development but decreased in the 2nd trimester, are located near ductal and islet structures. Direct and indirect co-cultures of hIECCs with PaSCs suggest that activation of PaSCs has opposing effects on beta-cell and exocrine cell differentiation during human fetal pancreas development, and that these effects may be dependent on Notch signaling.
| S-EPMC8418189 | biostudies-literature
Project description:Pancreatic β-cells are a critical cell type in the pathology of diabetes. Models of genetic syndromes featuring diabetes can provide novel mechanistic insights into regulation of β-cells in the context of disease. We previously examined β-cell mass in models of two ciliopathies, Alström Syndrome (AS) and Bardet-Biedl Syndrome (BBS), which are similar in the presence of metabolic phenotypes, including obesity, but exhibit strikingly different rates of diabetes. Zebrafish models of these disorders show deficient β-cells with diabetes in AS models and an increased β-cells absent diabetes in BBS models, indicating β-cell generation or maintenance that correlates with disease prevalence. Using transcriptome analyses, differential expression of several exocrine pancreas proteases with directionality that was consistent with β-cell numbers were identified. Based on these lines of evidence, we hypothesized that pancreatic proteases directly impact β-cells. In the present study, we examined this possibility and found that pancreatic protease genes contribute to proper maintenance of normal β-cell numbers, proliferation in larval zebrafish, and regulation of AS and BBS β-cell phenotypes. Our data suggest that these proteins can be taken up directly by cultured β-cells and ex vivo murine islets, inducing proliferation in both. Endogenous uptake of pancreatic proteases by β-cells was confirmed in vivo using transgenic zebrafish and in intact murine pancreata. Taken together, these findings support a novel proliferative signaling role for exocrine pancreas proteases through interaction with endocrine β-cells.
| S-EPMC8249909 | biostudies-literature
Project description:The metabolic stress hormone FGF21 is highly expressed in exocrine pancreas, where its levels are increased by refeeding and chemically induced pancreatitis. However, its function in the exocrine pancreas remains unknown. Here, we show that FGF21 stimulates digestive enzyme secretion from pancreatic acinar cells through an autocrine/paracrine mechanism that requires signaling through a tyrosine kinase receptor complex composed of an FGF receptor and β-Klotho. Mice lacking FGF21 accumulate zymogen granules and are susceptible to pancreatic ER stress, an effect that is reversed by administration of recombinant FGF21. Mice carrying an acinar cell-specific deletion of β-Klotho also accumulate zymogen granules but are refractory to FGF21-stimulated secretion. Like the classical post-prandial secretagogue, cholecystokinin (CCK), FGF21 triggers intracellular calcium release via PLC-IP3R signaling. However, unlike CCK, FGF21 does not induce protein synthesis, thereby preventing protein accumulation. Thus, pancreatic FGF21 is a digestive enzyme secretagogue whose physiologic function is to maintain acinar cell proteostasis.
| S-EPMC5299054 | biostudies-literature
Project description:Exocrine pancreas abnormalities are increasingly recognized as features of type 1 diabetes. We previously reported reduced serum trypsinogen levels and in a separate study, smaller pancreata at and before disease onset. We hypothesized that three pancreas enzymes (amylase, lipase, and trypsinogen) might serve as serological biomarkers of pancreas volume and risk for type 1 diabetes. Amylase, lipase, and trypsinogen were measured from two independent cohorts, together comprising 800 serum samples from single-autoantibody-positive (1AAb+) and multiple-AAb+ (≥2AAb+) subjects, individuals with recent-onset or established type 1 diabetes, their AAb-negative (AAb-) first-degree relatives, and AAb- control subjects. Lipase and trypsinogen were significantly reduced in ≥2AAb+, recent-onset, and established type 1 diabetes subjects versus control subjects and 1AAb+, while amylase was reduced only in established type 1 diabetes. Logistic regression models demonstrated trypsinogen plus lipase (area under the receiver operating characteristic curve [AUROC] = 81.4%) performed equivalently to all three enzymes (AUROC = 81.4%) in categorizing ≥2AAb+ versus 1AAb+ subjects. For cohort 2 (n = 246), linear regression demonstrated lipase and trypsinogen levels could individually and collectively serve as indicators of BMI-normalized relative pancreas volume (RPVBMI, P < 0.001), previously measured by MRI. Serum lipase and trypsinogen levels together provide the most sensitive serological biomarker of RPVBMI and may improve disease staging in pretype 1 diabetes.
| S-EPMC7980193 | biostudies-literature
Project description:Both endocrine and exocrine pancreatic cells arise from pancreatic-duodenal homeobox 1 (pdx1)-positive progenitors. The molecular mechanisms controlling cell fate determination and subsequent proliferation, however, are poorly understood. Unlike endocrine cells, less is known about exocrine cell specification. We report here the identification and characterization of a novel exocrine cell determinant gene, exocrine differentiation and proliferation factor (exdpf), which is highly expressed in the exocrine cell progenitors and differentiated cells of the developing pancreas in zebrafish. Knockdown of exdpf by antisense morpholino caused loss or significant reduction of exocrine cells due to lineage-specific cell cycle arrest but not apoptosis, whereas the endocrine cell mass appeared normal. Real-time PCR results demonstrated that the cell cycle arrest is mediated by up-regulation of cell cycle inhibitor genes p21(Cip), p27(Kip), and cyclin G1 in the exdpf morphants. Conversely, overexpression of exdpf resulted in an overgrowth of the exocrine pancreas and a severe reduction of the endocrine cell mass, suggesting an inhibitory role for exdpf in endocrine cell progenitors. We show that exdpf is a direct target gene of pancreas-specific transcription factor 1a (Ptf1a), a transcription factor critical for exocrine formation. Three consensus Ptf1a binding sites have been identified in the exdpf promoter region. Luciferase assay demonstrated that Ptf1a promotes transcription of the exdpf promoter. Furthermore, exdpf expression in the exocrine pancreas was lost in ptf1a morphants, and overexpression of exdpf successfully rescued exocrine formation in ptf1a-deficient embryos. Genetic evidence places expdf downstream of retinoic acid (RA), an instructive signal for pancreas development. Knocking down exdpf by morpholino abolished ectopic carboxypeptidase A (cpa) expression induced by RA. On the other hand, exdpf mRNA injection rescued endogenous cpa expression in embryos treated with diethylaminobenzaldehyde, an inhibitor of RA signaling. Moreover, exogenous RA treatment induced anterior ectopic expression of exdpf and trypsin in a similar pattern. Our study provides a new understanding of the molecular mechanisms controlling exocrine cell specification and proliferation by a novel gene, exdpf. Highly conserved in mammals, the expression level of exdpf appears elevated in several human tumors, suggesting a possible role in tumor pathogenesis.
| S-EPMC2586380 | biostudies-literature