Enhanced Insulin Secretion Through Upregulation of Transcription Factors by Hydroalcoholic Extract of Securigera securidaca Seeds in Diabetic Animal Model.

AIM: In previous studies, the researchers observed an increase in insulin secretion in STZ-treated diabetic rats following treatment with the hydroalcoholic extract of Securigera securidaca (HESS) seeds. This study focuses on the relationship between the antioxidant properties of HESS with changes in diabetic pancreatic tissue and the gene expression of factors that impact insulin secretion. METHODS: In this controlled experimental study, three varying doses of HESS were administered to three groups of diabetic rats induced by STZ. Oxidative stress indicators like total antioxidant capacity (TAC), total oxidant status (TOS) and malondialdehyde were assessed in both pancreatic and liver tissues. Pancreatic histology was studied post-haematoxylin staining. Insulin and FGF21 levels in the blood were measured using the ELISA method. The expression of Nrf2 and FGF21 genes in the pancreas and liver, along with MafA and PDX-1 genes in the pancreas, was quantified using real-time PCR. RESULTS: The administration of HESS in varying doses led to a dose-dependent rise in blood insulin levels and a decrease in blood glucose levels and oxidative stress. By reducing oxidative stress, HESS treatment lowered the heightened levels of NRF2 and FGF21 in the liver and pancreas of diabetic rats, improving pancreatic tissue health. As oxidative stress decreased, the expression of MafA and PDX1 genes in the pancreas approached levels seen in healthy rats. CONCLUSION: HESS elicits an increase in insulin secretion through the mitigation of oxidative stress and tissue damage, as well as the modulation of gene expression related to the insulin transcription factors PDX-1 and MafA.

Integrative multi-omics increase resolution of the sea urchin posterior gut gene regulatory network at single-cell level.

Drafting gene regulatory networks (GRNs) requires embryological knowledge pertaining to the cell type families, information on the regulatory genes, causal data from gene knockdown experiments and validations of the identified interactions by cis-regulatory analysis. We use multi-omics involving next-generation sequencing to obtain the necessary information for drafting the Strongylocentrotus purpuratus (Sp) posterior gut GRN. Here, we present an update to the GRN using: (1) a single-cell RNA-sequencing-derived cell atlas highlighting the 2 day-post-fertilization (dpf) sea urchin gastrula cell type families, as well as the genes expressed at the single-cell level; (2) a set of putative cis-regulatory modules and transcription factor-binding sites obtained from chromatin accessibility ATAC-seq data; and (3) interactions directionality obtained from differential bulk RNA sequencing following knockdown of the transcription factor Sp-Pdx1, a key regulator of gut patterning in sea urchins. Combining these datasets, we draft the GRN for the hindgut Sp-Pdx1-positive cells in the 2 dpf gastrula embryo. Overall, our data suggest the complex connectivity of the posterior gut GRN and increase the resolution of gene regulatory cascades operating within it.

Rosa canina extract relieves methylation alterations of pancreatic genes in STZ-induced diabetic rats : Gene methylation in diabetic rats treated with an extract.

BACKGROUND: Diabetes is a chronic metabolic disease that affects many parts of the body. Considering diabetes as a beta cells' defect and loss, the focus is on finding mechanisms and compounds involved in stimulating the function and regeneration of pancreatic ß-cells. DNA methylation as an epigenetic mechanism plays a pivotal role in the ß-cells' function and development. Considering the regenerative and anti-diabetic effects of Rosa canina extract, this study aimed to assess the methylation levels of Pdx-1, Pax-4, and Ins-1 genes in diabetic rats treated with Rosa Canina extract. METHODS AND RESULTS: Streptozotocin-induced diabetic rats were used to evaluate the frequency of Pdx-1, Pax-4, and Ins-1 gene methylation. Treatment groups were exposed to Rosa canina as spray-dried and decoction extracts. Following blood glucose measurement, pancreatic DNA was extracted and bisulfited. Genes' methylation was measured using MSP-PCR and qRT-PCR techniques. Oral administration of Rosa canina extracts significantly reduced blood sugar levels in diabetic rats compared to the control group. The methylation levels of the Pdx-1, Pax-4, and Ins-1 genes promoter in streptozotocin-induced diabetic rats increased compared to the control rats while, the treatment of diabetic rats with Rosa canina extracts, spray-dried samples especially, led to a decreased methylation in these genes. CONCLUSION: The results of this study showed that Rosa canina extract as a spray-dried sample could be effective in treating diabetes by regulating the methylation of genes including Pdx-1, Pax-4, and Ins-1 involved in the activity and regeneration of pancreatic islet cells.

[Characteristics of gastric neuroendocrine tumors and the PDX-1 transcription factor expression]. / Kharakteristika neiroendokrinnykh opukholei zheludka i ekspressiya v nikh transkriptsionnogo faktora PDX-1.

OBJECTIVE: To study the features of gastric neuroendocrine tumors (NETs) and the diagnostic and prognostic significance of PDX-1 expression in them. MATERIAL AND METHODS: 207 NETs identified in 56 men and 115 women (59 had multiple NETs), and 94 cases of gastric cancer (comparison group) were studied morphologically and immunohistochemically. RESULTS: In more than half of the cases (54.93%), NETs were localized in the body of the stomach; the cardiac and antral parts of the stomach accounted for 8.64% and 11.73%, respectively. NETs of the cardiac region predominated in men, and of the body and antrum - in women. NETs of the cardiac region predominated in men, and of the body and antrum - in women. The vast majority of NETs were highly differentiated (89.20%), of which Grade 1, 2 and 3 were 55.41%, 40.76% and 3.82%, respectively. Neuroendocrine carcinomas (NEC) accounted for 10.80% of all NET cases. NECs were more often localized in the cardiac part of the stomach and accounted for 35.71% of all NETs in the cardiac part. The share of NEC among all NETs of the antrum was 15.79%, of the body of the stomach - only 3.37%. Metastases were found in 17.90% of NETs. Expression of PDX-1 was detected in 44.73% of NETs, 70% of NECs and 74.50% of gastric cancers. CONCLUSION: PDX-1 is involved in the mechanisms of precancerous and cancerous lesions of the stomach and its overexpression is detected in the majority of the most malignant NETs and gastric cancers.

PDX1, a transcription factor essential for organ differentiation, regulates SERCA-dependent Ca2+ homeostasis in sensory neurons.

Pancreatic and duodenal homeobox 1 (PDX1) is a transcription factor required for the development and differentiation of the pancreas. Previous studies indicated that PDX1 expression was restricted to the gastrointestinal tract. Using a cre-dependent reporter, we observed PDX1-dependent expression of tdtomato (PDX1-tom) in a subpopulation of sensory nerves. Many of these PDX1-tom afferents expressed the neurofilament 200 protein and projected to the skin. Tdtomato-labeled terminals were associated with hair follicles in the form of longitudinal and circumferential lanceolate endings suggesting a role in tactile and proprioceptive perception. To begin to examine the functional significance of PDX1 in afferents, we used Fura-2 imaging to examine calcium (Ca2+) handling under naïve and nerve injury conditions. Neuropathic injury is associated with increased intracellular Ca2+ signaling that in part results from dysregulation of the sarco/endoplasmic reticulum calcium transport ATPase (SERCA). Here we demonstrate that under naïve conditions, PDX1 regulates expression of the SERCA2B isoform in sensory neurons. In response to infraorbital nerve injury, a significant reduction of PDX1 and SERCA2B expression and dysregulation of Ca2+ handling occurs in PDX1-tom trigeminal ganglia neurons. The identification of PDX1 expression in the somatosensory system and its regulation of SERCA2B and Ca2+ handling provide a new mechanism to explain pathological changes in primary afferents that may contribute to pain associated with nerve injury.

CK2 activity is crucial for proper glucagon expression.

AIMS/HYPOTHESIS: Protein kinase CK2 acts as a negative regulator of insulin expression in pancreatic beta cells. This action is mainly mediated by phosphorylation of the transcription factor pancreatic and duodenal homeobox protein 1 (PDX1). In pancreatic alpha cells, PDX1 acts in a reciprocal fashion on glucagon (GCG) expression. Therefore, we hypothesised that CK2 might positively regulate GCG expression in pancreatic alpha cells. METHODS: We suppressed CK2 kinase activity in αTC1 cells by two pharmacological inhibitors and by the CRISPR/Cas9 technique. Subsequently, we analysed GCG expression and secretion by real-time quantitative RT-PCR, western blot, luciferase assay, ELISA and DNA pull-down assays. We additionally studied paracrine effects on GCG secretion in pseudoislets, isolated murine islets and human islets. In vivo, we examined the effect of CK2 inhibition on blood glucose levels by systemic and alpha cell-specific CK2 inhibition. RESULTS: We found that CK2 downregulation reduces GCG secretion in the murine alpha cell line αTC1 (e.g. from 1094±124 ng/l to 459±110 ng/l) by the use of the CK2-inhibitor SGC-CK2-1. This was due to a marked decrease in Gcg gene expression through alteration of the binding of paired box protein 6 (PAX6) and transcription factor MafB to the Gcg promoter. The analysis of the underlying mechanisms revealed that both transcription factors are displaced by PDX1. Ex vivo experiments in isolated murine islets and pseudoislets further demonstrated that CK2-mediated reduction in GCG secretion was only slightly affected by the higher insulin secretion after CK2 inhibition. The kidney capsule transplantation model showed the significance of CK2 for GCG expression and secretion in vivo. Finally, CK2 downregulation also reduced the GCG secretion in islets isolated from humans. CONCLUSIONS/INTERPRETATION: These novel findings not only indicate an important function of protein kinase CK2 for proper GCG expression but also demonstrate that CK2 may be a promising target for the development of novel glucose-lowering drugs.

What Do We Know about Neonatal Diabetes Caused by PDX1 Mutations?

INTRODUCTION: Neonatal diabetes mellitus (NDM) is characterized by severe hyperglycemia, usually diagnosed in the first few months of an individual's life. It is a genetic disease and one of the main forms of monogenic diabetes. Changes in different genes have already been associated with NDM, including changes in the gene PDX1. METHODS: In this review, we intend to summarize all neonatal diabetes cases caused by PDX1 mutations reported in the literature. For this purpose, we searched keywords in the literature from PubMed and articles cited by the HGMD database. The search retrieved 84 articles, of which 41 had their full text accessed. After applying the study exclusion criteria, nine articles were included. RESULTS: Of those articles, we detected thirteen cases of NDM associated with changes in PDX1; the majority in homozygous or compound heterozygous patients. Until now, variants in the PDX1 gene have been a rare cause of NDM; however, few studies have included the screening of this gene in the investigation of neonatal diabetes. CONCLUSION: In this review, we reinforce the importance of the PDX1 gene inclusion in genetic NGS panels for molecular diagnosis of NDM, and systematic morphological and functional exams of the pancreas when NDM is present.

PDX1 Methylation, NGN3 and Pax6 Expression Levels in Pregnant Women with Gestational Diabetes Mellitus and their association with neonatal blood sugars and birth weight.

Objective: To investigate the correlation of maternal PDX1 methylation, NGN3 and Pax6 expression levels with neonatal blood sugars and birth weight in pregnant women with GDM and non GDM. Methods: This was a prospective cohort study. Total 80 pregnant women who were examined and delivered in the Department of Obstetrics of Affiliated Hospital of Hebei University from January 2019 to June 2022 were recruited and divided into two groups according to the results of oral glucose tolerance test (OGTT): the control group and the observation group, with 40 cases in each group. PDXl methylation rate was measured by the methylation-specific PCR method, whereas gene expression levels of PDX1, NGN3 and Pax6 were measured by RT-PCR meanwhile, neonatal blood glucose and hemoglobin A1c (HbA1c) levels were also measured. Results: In comparison with the control group, the observation group had higher levels of FBG, 2-hour postprandial blood glucose (2hPBG) and HbA1c (P<0.05). Neonatal birth weight and insulin levels in the observation group were significantly higher than those in the control group, while Apgar scores and blood glucose were lower than those in the control group(P<0.05). Moreover, the observation group had significantly lower gene expression levels of PDX1, NGN3 and Pax6, and a higher PDX1 methylation rate than the control group (P<0.05). Correlation analysis revealed a negative correlation between neonatal blood glucose levels and PDX1, NGN3 and Pax6 levels in the observation group, with statistical significance (P<0.05). Conclusion: Changes in maternal PDX1 methylation, NGN3 and Pax6 expression levels may lead to abnormal glucose metabolism in neonates, which has a close bearing on neonatal hypoglycemia and blood glucose levels caused by GDM.

Unlocking ß-cell restoration: The crucial role of PDX1 in diabetes therapy.

Diabetes has been a significant healthcare problem worldwide for a considerable period. The primary objective of diabetic treatment plans is to control the symptoms associated with the pathology. To effectively combat diabetes, it is crucial to comprehend the disease's etiology, essential factors, and the relevant processes involving ß-cells. The development of the pancreas, maturation, and maintenance of ß-cells, and their role in regular insulin function are all regulated by PDX1. Therefore, understanding the regulation of PDX1 and its interactions with signaling pathways involved in ß-cell differentiation and proliferation are crucial elements of alternative diabetes treatment strategies. The present review aims to explore the protective role of PDX1 in ß-cell proliferation through signaling pathways. The main keywords chosen for this review include "PDX1 for ß-cell mass," "ß-cell proliferation," "ß-cell restoration via PDX1," and "mechanism of PDX1 in ß-cells." A comprehensive literature search was conducted using various internet search engines, such as PubMed, Science Direct, and other publication databases. We summarize several approaches to generating ß-cells from alternative cell sources, employing PDX1 under various modified growth conditions and different transcriptional factors. Our analysis highlights the unique potential of PDX1 as a promising target in molecular and cell-based therapies for diabetes.

Repression of latent NF-κB enhancers by PDX1 regulates ß cell functional heterogeneity.

Interactions between lineage-determining and activity-dependent transcription factors determine single-cell identity and function within multicellular tissues through incompletely known mechanisms. By assembling a single-cell atlas of chromatin state within human islets, we identified ß cell subtypes governed by either high or low activity of the lineage-determining factor pancreatic duodenal homeobox-1 (PDX1). ß cells with reduced PDX1 activity displayed increased chromatin accessibility at latent nuclear factor κB (NF-κB) enhancers. Pdx1 hypomorphic mice exhibited de-repression of NF-κB and impaired glucose tolerance at night. Three-dimensional analyses in tandem with chromatin immunoprecipitation (ChIP) sequencing revealed that PDX1 silences NF-κB at circadian and inflammatory enhancers through long-range chromatin contacts involving SIN3A. Conversely, Bmal1 ablation in ß cells disrupted genome-wide PDX1 and NF-κB DNA binding. Finally, antagonizing the interleukin (IL)-1ß receptor, an NF-κB target, improved insulin secretion in Pdx1 hypomorphic islets. Our studies reveal functional subtypes of single ß cells defined by a gradient in PDX1 activity and identify NF-κB as a target for insulinotropic therapy.

The effects of EGCG supplementation on pancreatic islet α and ß cells distribution in adult male mice.

Tea and tea products are widely used as the most popular beverage in the world. EGCG is the most abundant bioactive tea polyphenol in green tea, which has positive effects on the prevention and treatment of diabetes. However, the impact of EGCG exposure on glucose homeostasis and islets in adult mice have not been reported. In this study, we studied glucose homeostasis and the morphological and molecular changes of pancreatic islet α and ß cells in adult male mice after 60 d of exposure to 1 and 10 mg/kg/day EGCG by drinking water. Glucose homeostasis was not affected in both EGCG groups. The expression of pancreatic duodenal homebox1 (Pdx1) in ß cells was upregulated, which might be related to increased insulin level, ß cell mass and ß cell proliferation in 10 mg/kg/day EGCG group. The expression of aristaless-related homeobox (Arx) in α cells did not change significantly, which corresponded with the unchanged α-cell mass. The significant reduction of musculoaponeurotic fibrosarcoma oncogene homolog B (MafB) positive α-cells might be associated with decreased glucagon level in both EGCG groups. These results suggest that EGCG supplementation dose-dependent increases ß cell mass of adult mice and affects the levels of serum insulin and glucagon. Our results show that regular tea drinking in healthy people may have the possibility of preventing diabetes.

Differentiation of insulin-producing cells from human umbilical cord mesenchymal stem cells infected by MAFA-PDX1 overexpressed lentivirus / 中国组织工程研究

BACKGROUND:Transplantation of stem cell-derived islet β cells has been considered effective for the treatment of type 1 diabetes.Human umbilical cord mesenchymal stem cell is an ideal cellular source,but with a low differentiation efficiency to islet β cells. OBJECTIVE:To explore the possibility of human umbilical cord mesenchymal stem cells modified by MAFA and PDX1 to differentiate into insulin-producing cells. METHODS:MAFA-PDX1 lentivirus expression vectors were constructed.The efficiency and potentiality of human umbilical cord mesenchymal stem cells differentiated into insulin-producing cells with three methods were compared by cell morphology,RT-qPCR,and dithizone staining[protocol A:Simple lentivirus group;protocol B:Drug(nicotinamide β-mercaptoethanol)induction followed by lentivirus group;protocol C:lentivirus and drug induction group]. RESULTS AND CONCLUSION:(1)Morphological change of cells:Cell morphology was all altered after the induction of three protocols.At day 11,human umbilical cord mesenchymal stem cells induced by protocol B showed the most cell clusters among the three protocols,appearing aggregated islet-like cell clusters.(2)Islet-related gene expression detected by RT-qPCR:Horizontal comparison of the three protocols at the same induction time point showed that the expression levels of MAFA and PDX1 genes were the highest in protocol C on day 5 of induction,and those in protocol B were the highest on day 11 of induction.Human umbilical cord mesenchymal stem cells induced by protocol B had the greatest expression of GCG gene at day 5,INS and GLUT2 genes at day 11.(3)Dithizone staining to identify zinc ions:parts of the post-induced cells were stained brownish red by dithizone on day 11.The partial small island cells were stained brownish red with a darker color(positive expression)in protocol B.(4)It is concluded that the overexpression of MAFA and PDX1 can promote the differentiation of human umbilical cord mesenchymal stem cells into insulin-producing cells.The combination of MAFA-PDX1 gene modification and drug induction is superior to the single gene modification.

Effects of perinatal exposure to benzo[a]pyrene on the expressionof PDX-1 and TFAM in pancreas and mitochondrial DNA copynumber in offspring rats / 预防医学

Objective@#To observe the effects of perinatal exposure to benzo[a]pyrene (B[a]P) on the expression of pancreatic duodenal homeobox-1 (PDX-1) and mitochondrial transcription factor A (TFAM) and mitochondrial DNA copy number in offspring mice, and to explore the role of maternal exposure to B[a]P in the pancreatic function damage of offspring mice.@*Methods@#Forty pregnant rats were randomly divided into the control group, the lowest dose group (2 μg/kg), the low dose group (200 μg/kg), medium dose group (800 μg/kg) and high dose group (1 600 μg/kg), with 8 rats in each group. From day 1 of pregnancy, each exposed group was given 0.2 mL/100 g body weight of B[a]P and corn oil mixture by gavage once a day until 3 weeks after delivery, while the control group was given the same dose of corn oil. The pancreatic tissue of three-week-old mice were collected after abdominal anesthesia for insulin immunohistochemical detection. The protein and mRNA expression levels of PDX-1 and TFAM, as well as mitochondrial DNA copy number were detected. Spearman rank correlation analysis was used to analyze the correlation between B[a]P exposure dose and the above indicators.@*Results@#The insulin-positive area ratio and average optical density of insulin in the medium and the high dose groups were significantly lower than those in the control group (all P<0.05). The insulin-positive area ratio and average optical density of insulin were negatively correlated with the B[a]P dose (rs=-0.862 and -0.858, both P<0.05). The protein expression levels of PDX-1 and TFAM in the high dose group were significantly lower than those in the control group (both P<0.05). The protein expression levels of PDX-1 and TFAM were negatively correlated with the B[a]P dose (rs=-0.756 and -0.799, both P<0.05). The mRNA expression levels of PDX-1 and mitochondrial DNA copy number in the medium and high dose groups were significantly lower than those in the control group, and the mRNA expression level of TFAM in the high dose group was significantly lower than that in the control group (all P<0.05). The mRNA expression levels of PDX-1, TFAM, and mitochondrial DNA copy number were negatively correlated with the B[a]P dose (rs=-0.722, -0.550 and -0.840, all P<0.05).@*Conclusion@#Perinatal exposure to B[a]P can induce the damage of islet β cells in offspring rats, which may be related to the decreased expression of PDX-1 and TFAM and the copy number of mitochondrial DNA.

Dominant PDX1 deficiency causes highly penetrant diabetes at different ages, associated with obesity and exocrine pancreatic deficiency: Lessons for precision medicine.

OBJECTIVE: Heterozygous pathogenic or likely pathogenic (P/LP) PDX1 variants cause monogenic diabetes. We comprehensively examined the phenotypes of carriers of P/LP PDX1 variants, and delineated potential treatments that could be efficient in an objective of precision medicine. METHODS: The study primarily involved a family harboring a novel P/LP PDX1 variant. We then conducted an analysis of documented carriers of P/LP PDX1 variants, from the Human Gene Mutation Database (HGMD), RaDiO study, and Type 2 Diabetes Knowledge Portal (T2DKP) including 87 K participants. RESULTS: Within the family, we identified a P/LP PDX1 variant encoding p.G232S in four relatives. All of them exhibited diabetes, albeit with very different ages of onset (10-40 years), along with caudal pancreatic agenesis and childhood-onset obesity. In the HGMD, 79 % of carriers of a P/LP PDX1 variant displayed diabetes (with differing ages of onset from eight days of life to 67 years), 63 % exhibited pancreatic insufficiency and surprisingly 40 % had obesity. The impact of P/LP PDX1 variants on increased risk of type 2 diabetes mellitus was confirmed in the T2DKP. Dipeptidyl peptidase 4 inhibitor (DPP4i) and glucagon-like peptide-1 receptor agonist (GLP1-RA), enabled good glucose control without hypoglycemia and weight management. CONCLUSIONS: This study reveals diverse clinical presentations among the carriers of a P/LP PDX1 variant, highlighting strong variations in diabetes onset, and unexpectedly high prevalence of obesity and pancreatic development abnormalities. Clinical data suggest that DPP4i and GLP1-RA may be the best effective treatments to manage both glucose and weight controls, opening new avenue in precision diabetic medicine.

Unknown presentation of a rare genetic disorder: Monogenic diabetes in young type 4 presenting with hepatic cysts and procoagulant state.

Maturity onset diabetes in young (MODY) is the most common form of monogenic diabetes, which characteristically presents in adolescents and young adults. Till date, pathogenic variations involving 14 different genes have been causally implicated with the development of MODY. Maturity onset diabetes in young type 4 (MODY-4) is a very rare form of MODY. We present here case of 28-year-old nonobese male patient with distinct family history of diabetes spanning two generations, incidentally, detected to have a rare form of diabetes on genetic analysis when he presented with recurrent thromboembolic manifestations: deep vein thrombosis and pulmonary thromboembolism. Our case highlights a previously unknown disease association of a rare genetic disorder. Increasing awareness about this genetic disorder and early identification of such cases will enhance our understanding of hitherto unknown disease associations and the pathophysiological role of genetic mutations. This may contribute to the improved treatment and prevention of debilitating diseases such as diabetes.

Beclin1 is essential for the pancreas development.

Beclin1 (Becn1) is a multifunctional protein involved in autophagy regulation, membrane trafficking, and tumor suppression. In this study, we examined the roles of Becn1 in the pancreas development by generating mice with conditional deletion of Becn1 in the pancreas using pancreatic transcriptional factor 1a (Ptf1a)-Cre mice (Becn1f/f; Ptf1aCre/+). Surprisingly, loss of Becn1 in the pancreas resulted in severe pancreatic developmental defects, leading to insufficient exocrine and endocrine pancreatic function. Approximately half of Becn1f/f; Ptf1aCre/+ mice died immediately after birth. However, duodenum and neural tissue development were almost normal, indicating that pancreatic insufficiency was the cause of death. These findings demonstrated a novel role for Becn1 in pancreas morphogenesis, differentiation, and growth, and suggested that loss of this factor leaded to pancreatic agenesis at birth.

Biological activity of recombinant human PDX1 protein produced from Escherichia coli.

Pancreatic and duodenum homeobox 1 (PDX1) is considered as a pivotal transcription factor that acts as a "master regulator" in pancreatogenesis and maintenance of ß-cells. Earlier study has reported that PDX1 also functions as a tumor suppressor in human gastric cancer cells by inhibiting cell growth. Here, we report the bioactivity of the purified human PDX1 fusion protein using various assays like cell migration, proliferation, cell cycle analysis, and gene expression. In cancer cells, recombinant PDX1 protein reduced cell migration and proliferation, and arrested cell growth by inducing apoptosis in gastric cancer cells. In pancreatic ductal cancer cells, the application of the PDX1 protein resulted in the induction of insulin gene expression. The results of these experiments demonstrate the biological activity imparted by recombinant human PDX1 fusion protein on gastric and pancreatic cancer cells and its usefulness as a biological tool to elucidate its function in various cellular processes.

Islet hypoplasia of adult offspring rats caused by intrauterine chronic hypoxia is compensated by up-regulation of INS and PDX-1.

BACKGROUND: Intrauterine chronic hypoxia (ICH) can lead to pancreatic dysmetabolism in offspring. This study aimed to determine the changes in islet function of offspring through a rat ICH model and detect the factors affecting islet function. METHODS: Twenty couples of healthy Sprague - Dawley adult rats were randomly mated, and the pregnant rats were randomly allocated to ICH and normal control (NC) groups. Pregnant rats in the ICH group were placed in a hypoxic chamber with 13% oxygen concentration for hypoxia treatment twice a day for 4 h until delivery at 21 days. NC group is inlet with normal air from beginning to end. After delivery, blood was taken from the heart of pregnant rats for blood gas analysis. The weight of the offspring rats was measured at 12 h after birth and 16 weeks after birth. At 16 weeks, the immunohistochemical results of ß-cell total, islet area, insulin (INS), and glucose transporter 2 (GLUT2) proteins were obtained from the islets. The mRNA data of INS and pancreatic and duodenal homeobox 1 (PDX-1) genes were obtained from pancreas. RESULTS: We found the ß-cell total, islet area, and the positive cell area of INS and GLUT2 of offspring rats in ICH group were lower than those of NC group, while the levels of INS and PDX-1 genes were higher in ICH group than in NC group. CONCLUSIONS: ICH can lead to islet hypoplasia in adult male offspring rats. However, this is within the compensatory range.

Raptor levels are critical for ß-cell adaptation to a high-fat diet in male mice.

OBJECTIVE: The essential role of raptor/mTORC1 signaling in ß-cell survival and insulin processing has been recently demonstrated using raptor knock-out models. Our aim was to evaluate the role of mTORC1 function in adaptation of ß-cells to insulin resistant state. METHOD: Here, we use mice with heterozygous deletion of raptor in ß-cells (ßraHet) to assess whether reduced mTORC1 function is critical for ß-cell function in normal conditions or during ß-cell adaptation to high-fat diet (HFD). RESULTS: Deletion of a raptor allele in ß-cells showed no differences at the metabolic level, islets morphology, or ß-cell function in mice fed regular chow. Surprisingly, deletion of only one allele of raptor increases apoptosis without altering proliferation rate and is sufficient to impair insulin secretion when fed a HFD. This is accompanied by reduced levels of critical ß-cell genes like Ins1, MafA, Ucn3, Glut2, Glp1r, and specially PDX1 suggesting an improper ß-cell adaptation to HFD. CONCLUSION: This study identifies that raptor levels play a key role in maintaining PDX1 levels and ß-cell function during the adaptation of ß-cell to HFD. Finally, we identified that Raptor levels regulate PDX1 levels and ß-cell function during ß-cell adaptation to HFD by reduction of the mTORC1-mediated negative feedback and activation of the AKT/FOXA2/PDX1 axis. We suggest that Raptor levels are critical to maintaining PDX1 levels and ß-cell function in conditions of insulin resistance in male mice.

Expression and clinicopathological characteristics of PDX1, PTF1A, and SALL4 in large and small ducts of ectopic pancreas located in gastro-duodenum and jejunum.

An ectopic pancreas is defined as pancreatic tissue outside its normal location, anatomically separated from the pancreas. The transcription factor pancreas/duodenum homeobox protein 1 (PDX1) is involved in maintaining the pancreas and functions in early pancreatic development, beta cell differentiation, and endocrine non beta cells. Pancreatic transcription factor 1 subunit alpha (PTF1A) affects exocrine cell formation and regulation of acinar cell identity, and is expressed in exocrine cells as a transcription factor. The depletion of SALL4 disrupts self-renewal and induces differentiation. To clarify which of PDX1, PTF1A, or SALL4 determines the difference in Heinrich's classification, we examined the localization and number of positive cells. We analyzed the differential expression of PDX1, PTF1A, and SALL4 in large and small ducts in ectopic pancreas by immunohistochemistry. Results showed that the number of PTF1A-positive cells in large ducts was more widespread in type I than in type II in the gastro-duodenum, and more SALL4-positive cells were noticed in large ducts than in small ducts in the gastro-duodenum of type II. Our results revealed that PTF1A might promote exocrine differentiation in developing the pancreatic tissues, and that those with widespread expression differentiate into exocrine cells.