Pdx1 Levels Research Articles

Hesperidin activates the GLP-1R/cAMP-CREB/IRS2/PDX1 pathway to promote transdifferentiation of islet α cells into β cells Across the spectrum

Background and aimsIn all age, FoShou as a Chinese medicinal herb has been active in various kinds of Traditional Chinese medicine formula to treating diabetes. Hesperidin (HES), the main monomeric component of FoShou, has been extensively investigated for interventions with pathogenic mechanism of diabetes as well as subsequent treatment of associated complications. Islet β-cells have an essential effect on dynamically regulating blood sugar. Functional abnormalities in these cells and their death are strongly associated with the onset of diabetes. Therefore, induction of islet endocrine cell lineage re-editing for damaged βcell replenishment would be a promising therapeutic tool. Previously, it has been found that HES can protect islet β-cells in vivo, But, the regenerative function of HES in islet β cells and its role in promoting differential non-β cells transdifferentiation into β cells and cell fate rewriting associated mechanisms remain unclear.This work focused on investigating whether HES can induce islet α cells transdifferentiation into β cells for achieving damaged β cell regeneration and the causes and possible mechanisms involved in the process. Materials and methodsIn brief, 60 mg/kg/d streptozotocin (STZ) was administered intraperitoneally in each male C57bL/6J mouse raised by the high-sugar and high-fat diet (HFD) to create a diabetic mouse model with severe β-cell damage. After 28 consecutive days of HES treatment (160 mg/kg; 320 mg/kg; once daily, as appropriate). Tracing the dynamics of α as well as β cell transformation, together with β cells growth and apoptosis levels during treatment by cell lineage tracing. The self-enforcing transcriptional network on which the cell lineage is based is used as a clue to explore the underlying mechanisms. Guangdong Pharmaceutical University's Animal Experiment Ethics Committee (GDPulac2019180) approved all animal experiments. ResultsLocalization by cell lineage we find that transdifferentiated newborn β-cells derived from α cells appeared in the islet endocrine cell mass of DM mice under HES'action. Compared to the model group, expressed by Tunel staining and CXCL10 levels the overall apoptosis rate of β-cells of the pancreas were reduced,the inflammatory infiltration feedback from HE staining were lower.Ki-67 positive cells showed enhanced β-cell proliferation. Decreased HbA1c and blood glucose contents, elevated C-Peptide and insulin contents which respond to ability of nascent beta cells. Also upregulated the mRNA levels of MafA, Ngn3, PDX-1, Pax4 and Arx. Moreover, increased the expression of TGR5/cAMP-CREB/GLP-1 in mouse intestinal tissues and GLP-1/GLP-1R and cAMP-CREB/IRS2/PDX-1 in pancreatic tissues. ConclusionsHES directly affects β-cells, apart from being anti-apoptotic and reducing inflammatory infiltration. HES promotes GLP-1 release by intestinal L cells by activating the TGR5 receptor in DM mouse and regulating its response element CREB signaling. GLP-1 then uses the GLP-1/GLP-1R system to act on IRS2, IRS2 as a port to influence α precursor cells to express PDX-1, with the mobilization of Pax4 strong expression than Arx so that α cell lineage is finally reversed for achieving β cell endogenous proliferation.

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

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 β-cells. DNA methylation as an epigenetic mechanism plays a pivotal role in the β-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. 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. 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.

Examining the pancreatic regenerative potential of Nigella sativa in diabetic rats: Evaluation of histological changes and transcription factors pdx-1 and neurog-3 levels

Pancreatic β cell neogenesis and proliferation represent promising avenues for diabetes management. Nigella sativa, known for its potent anti-inflammatory and antioxidant properties, has demonstrated efficacy in promoting regeneration across various organ systems. This study investigates the potential of Nigella sativa in pancreatic regeneration by examining pancreatic histology in addition, the expression levels of the key transcription factors, comprising NEUROG-3, PDX-1, INS-1, and INS-2. Twenty-four rats were categorized in 4sets that is negative control, positive control, normal, and treatment. Diabetes was prompted through intraperitoneal administration of alloxan hydrate. After 21 days of diabetes induction, the treatment set was applied with N. sativa extract, the positive control set was administered Glibenclamide, while the negative control group received no treatment. Parameters such as biochemical markers, oxidative stress markers, pancreatic islet architecture changes, and the expression levels of the NEUROG-3, PDX-1, INS-1, and INS-2 were assessed. Data analysis, conducted through DMR Test and ANOVA with a 5% threshold of significance, revealed significant insights into the consequence of N. sativa on the parameters under investigation. The results propose a possible part for N. sativa in promoting pancreatic regeneration and warrant further exploration for its application in diabetes management.

Tangeretin enhances pancreatic beta-TC-6 function by ameliorating tunicamycin-induced cellular perturbations.

Pancreatic beta cell health and its insulin-secreting potential are severely compromised under the diabetic condition. One of the key mediators of beta cell dysfunction is endoplasmic reticulum (ER) stress. Pharmacological intervention of ER stress and associated complications in pancreatic beta cells may be an effective strategy for the management of diabetes. In the present study, we evaluated the efficacy of tangeretin, a citrus pentamethoxyflavone, in the alleviation of ER stress and associated perturbations in pancreatic Beta-TC-6 cell lines. Tunicamycin (pharmacological ER stress inducer) at subtoxic levels was observed to induce beta cell dysfunction by upregulation of intracellular ROS levels, lowering mitochondrial number/biogenesis and membrane potential, elevation of UPR markers, XBP-1, GADD153, and ER resident chaperones. Treatment with tangeretin was successful in improving the beta cell function by lowering the ROS levels and improving the mitochondrial biogenesis and mitochondrial membrane potential. Tangeretin also downregulated the expression levels of XBP-1, GADD153, and ER resident chaperones. GLUT2 expression, however, did not undergo any significant change under ER stress. We also observed altered expression of Pdx-1, TRB3, and p-Akt under the ER stress condition. Tangeretin augmented the expression levels of Pdx-1, and p-Akt while curtailing the expression of TRB3 in beta cells. Tunicamycin treatment suppressed the insulin levels, however, co-treatment with tangeretin could only marginally improve the levels. Targeting ER stress and associated pathways in pancreatic Beta-TC-6 cell lines by tangeretin can be an effective strategy for improving beta cell function.

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

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. 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. 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). 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.

Comprehensive Search for GPCR Compounds which Can Enhance MafA and/or PDX-1 Expression Levels Using a Small Molecule Compound Library.

It has been shown that chronic hyperglycemia gradually decreases insulin biosynthesis and secretion which is accompanied by reduced expression of very important insulin gene transcription factors MafA and PDX-1. Such phenomena are well known as β-cell glucose toxicity. It has been shown that the downregulation of MafA and/or PDX-1 expression considerably explains the molecular mechanism for glucose toxicity. However, it remained unknown which molecules can enhance MafA and/or PDX-1 expression levels. In this study, we comprehensively searched for G protein-coupled receptor (GPCR) compounds which can enhance MafA and/or PDX-1 expression levels using a small molecule compound library in pancreatic β-cell line MIN6 cells and islets isolated from nondiabetic C57BL/6 J mice and obese type 2 diabetic C57BL/KsJ-db/db mice. We found that fulvestrant and dexmedetomidine hydrochloride increased MafA, PDX-1, or insulin expression levels in MIN6 cells. We confirmed that fulvestrant and dexmedetomidine hydrochloride increased MafA, PDX-1, or insulin expression levels in islets from nondiabetic mice as well. Furthermore, these reagents more clearly enhanced MafA, PDX-1, or insulin expression levels in islets from obese type 2 diabetic db/db mice in which MafA and PDX-1 expression levels are reduced due to glucose toxicity. In conclusion, fulvestrant and dexmedetomidine hydrochloride increased MafA, PDX-1, or insulin expression levels in MIN6 cells and islets from nondiabetic mice and obese type 2 diabetic db/db mice. To the best of our knowledge, this is the first report showing some molecule which can enhance MafA and/or PDX-1 expression levels. Therefore, although further extensive study is necessary, we think that the information in this study could be, at least in part, useful at some point such as in the development of new antidiabetes medicine based on the molecular mechanism of β-cell glucose toxicity in the future.

Pancreatic regenerative potential of manuka honey evidenced through pancreatic histology and levels of transcription factors in diabetic rat model

BackgroundDiabetes mellitus is a commonly occurring metabolic disorder accompanied by high morbidity and alarming mortality. Besides various available therapies, induction of pancreatic regeneration has emerged as a promising strategy for alleviating the damaging effect of diabetes. Honey, a potent antioxidative and anti-inflammatory agent, has been reported in the literature archive to exhibit favourable results in the regeneration process of several organ systems. DesignThe current research work was intended to explore the potential role of manuka honey in pancreatic regeneration in alloxan-induced diabetic rats by accessing the pancreatic histology and levels of relevant transcription factors, including MAFA, PDX-1, INS-1, INS-2, NEUROG3, NKX6-1, and NEUROD. An equal number of rats were allocated to all four experimental groups: normal, negative control, positive control, and treatment group. Diabetes was induced in all groups except normal through a single intraperitoneal dose of alloxan monohydrate. No subsequent treatment was given to the negative control group, while the positive control and treatment groups were supplemented with metformin (150 mg/kg/day) and manuka honey (3 g/kg/day), respectively. ResultsStatistical comparison of glucose and insulin levels, oxidative stress indicators, changes in the architecture of pancreatic islets, and expression levels of regeneration-associated transcription factors advocated the potential role of manuka honey in ameliorating the alloxan-induced hyperglycaemia, hyperinsulinemia, oxidative stress, and necrotic changes in islets along with significant upregulation of relevant transcription factors. ConclusionThis suggests to us the auspicious role of antioxidants in honey in pancreatic regeneration and advocates the favourable role of manuka honey in combating diabetes mellitus.

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

ObjectiveThe essential role of raptor/mTORC1 signaling in β-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 β-cells to insulin resistant state. MethodHere, we use mice with heterozygous deletion of raptor in β-cells (βraHet) to assess whether reduced mTORC1 function is critical for β-cell function in normal conditions or during β-cell adaptation to high-fat diet (HFD). ResultsDeletion of a raptor allele in β-cells showed no differences at the metabolic level, islets morphology, or β-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 β-cell genes like Ins1, MafA, Ucn3, Glut2, Glp1r, and specially PDX1 suggesting an improper β-cell adaptation to HFD. ConclusionThis study identifies that raptor levels play a key role in maintaining PDX1 levels and β-cell function during the adaptation of β-cell to HFD. Finally, we identified that Raptor levels regulate PDX1 levels and β-cell function during β-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 β-cell function in conditions of insulin resistance in male mice.

82-OR: NRF2 Regulates Neonatal ß-Cell Mass Expansion

The pediatric population suffers from increased incidence of both major types of diabetes in recent decades, highlighting the urgent need for discovering mechanisms that regulate functional β-cell mass. We found that the master antioxidant regulator, Nrf2, is required for adaptive adult β-cell expansion under hypercaloric conditions via regulation of β-cell proliferation, β-cell survival, and maintenance of β-cell identity. Additionally, we found that Nrf2 expression in β-cells of 7-day-old mice is 15-fold higher of that in adult β-cells (p&amp;lt;0.0001, n=6). Based on these observations, we hypothesized that Nrf2 regulates β-cell proliferation and survival at early stages of life and contributes to the maintenance of normal β-cell mass later in life. To test this, we deleted Nrf2 in β-cells by crossing InsCre with Nrf2lox/lox mice (βNrf2KO). βNrf2KO mice at 28 days of age exhibited a 65% reduction of β-cell mass compared to control mice (p&amp;lt;0.0005, n=6). Importantly, at 7 days of age, βNrf2KO mice displayed a 65% reduction of β-cell proliferation (p&amp;lt;0.0001, n=6), a 22% reduction of nuclear Pdx1 levels (p&amp;lt;0.0001, n=6), a 5.84-fold increase in β-cell death (±0.04, p&amp;lt;0.001, n=6) and a 2.93-fold increase in β-cell oxidative stress (p&amp;lt;0.001, n=6) compared to control mice. Surprisingly, daily administration of antioxidant NAC to 7-day-old βNrf2KO mice only partially restored β-cell proliferation but completely blunted oxidative stress compared to control mice. This suggests that neonatal β-cell proliferation induced by Nrf2 relies on additional mechanisms beyond oxidative stress. Interestingly, RNAseq of isolated islets from 7-day-old βNrf2KO mice showed decreased expression of mitochondrial encoded genes and upregulation of stress-responsive genes. This suggests that Nrf2 controls β-cell proliferation by regulating mitochondrial bioenergetics. We conclude that Nrf2 is required for β-cell mass expansion in neonatal ages by controlling β-cell proliferation, identity, and survival. Disclosure S.Baumel-alterzon: None. L.S.Katz: None. L.Lambertini: None. A.Garcia-ocana: Consultant; Sun Pharmaceutical Industries Ltd. D.Scott: None. Funding National Institutes of Health (DK128387, DK114338)

Promoting β-cells function by the recapitulation of in vivo microenvironmental differentiation signals.

The study aims to transdifferentiate rat bone marrow-derived mesenchymal stem cells (BM-MSCs) more efficiently into islet-like cells and encapsulate and transplant them with vital properties like stability, proliferation, and metabolic activity enhanced for the treatment of T1DM. Trans-differentiation of BM-MCs into islet-like cells induced by high glucose concentration combined with Nicotinamide, ꞵ-Mercaptoethanol, ꞵ-Cellulin, and IGF-1. Glucose challenge assays and gene expression profiles were used to determine functionality. Microencapsulation was performed using the vibrating nozzle encapsulator droplet method with a 1% alginate concentration. Encapsulated ꞵ-cells were cultured in a fluidized-bed bioreactor with 1850 μL/min fluid flow rates and a superficial velocity of 1.15cm/min. The procedure was followed by transplanting transdifferentiated cells into the omentum of streptozotocin (STZ)-induced diabetic Wistar rats. Changes in weight, glucose, insulin, and C-peptide levels were monitored for 2months after transplantation. PDX1, INS, GCG, NKx2.2, NKx6.1, and GLUT2 expression levels revealed the specificity of generated β-cells with higher viability (about 20%) and glucose sensitivity about twofold more. The encapsulated β-cells decreased the glucose levels in STZ-induced rats significantly (P < 0.05) 1week after transplantation. Also, the weight and levels of insulin and C-peptide reached the control group. In contrast to the treated, the sham group displayed a consistent decline in weight and died when loss reached > 20% at day ~ 55. The coated cells secrete significantly higher amounts of insulin in response to glucose concentration changes. Enhanced viability and functionality of β-cells can be achieved through differentiation and culturing, a promising approach toward insulin therapy alternatives.

CLEC11A improves insulin secretion and promotes cell proliferation in human beta-cells.

Beta-cell dysfunction is a hallmark of disease progression in patients with diabetes. Research has been focused on maintaining and restoring beta-cell function during diabetes development. The aims of this study were to explore the expression of C-type lectin domain containing 11A (CLEC11A), a secreted sulphated glycoprotein, in human islets and to evaluate the effects of CLEC11A on beta-cell function and proliferation in vitro. To test these hypotheses, human islets and human EndoC-βH1 cell line were used in this study. We identified that CLEC11A was expressed in beta-cells and alpha-cells in human islets but not in EndoC-βH1 cells, whereas the receptor of CLEC11A called integrin subunit alpha 11 was found in both human islets and EndoC-βH1 cells. Long-term treatment with exogenous recombinant human CLEC11A (rhCLEC11A) accentuated glucose-stimulated insulin secretion, insulin content, and proliferation from human islets and EndoC-βH1 cells, which was partially due to the accentuated expression levels of transcription factors MAFA and PDX1. However, the impaired beta-cell function and reduced mRNA expression of INS and MAFA in EndoC-βH1 cells that were caused by chronic palmitate exposure could only be partially improved by the introduction of rhCLEC11A. Based on these results, we conclude that rhCLEC11A promotes insulin secretion, insulin content, and proliferation in human beta-cells, which are associated with the accentuated expression levels of transcription factors MAFA and PDX1. CLEC11A, therefore, may provide a novel therapeutic target for maintaining beta-cell function in patients with diabetes.

An artificial LAMA2-GelMA hydrogel microenvironment for the development of pancreatic endocrine progenitors

The biomimetic pancreatic microenvironment improves the differentiation efficiency and function of human embryonic stem cell-derived β-cells (SC-β cells). Thus, a laminin subunit alpha 2-gelatin methacrylate (LAMA2-GelMA) hybrid hydrogel as a bionics carrier for the formation and maturation of endocrine lineage was developed in our research, based on pancreas proteomics analysis of postnatal mice. Pancreatic endocrine cells cultured on the hybrid hydrogel in vitro, which was composed of 0.5 μg/mL LAMA2 protein and 4% GelMA, the expression of transcription factors (TFs), including NKX6.1, NKX6.2, and NEUROD1 were upregulated. Single-cell transcriptomics was performed after LAMA2 knockdown during the early differentiation of pancreatic progenitor (PP) cells, a marked decrease in the forkhead box protein A2 (FOXA2+)/GATA-binding factor 6 (GATA6+) cluster was detected. Also, we clarified that as a receptor of LAMA2, integrin subunit alpha 7 (ITGA7) participated in Integrin-AKT signaling transduction and influenced the protein levels of FOXA2 and PDX1. In vivo experiments showed that, PP cells encapsulated in the LAMA2-GelMA hydrogel exhibited higher serum C-peptide levels compared to the GelMA and Matrigel groups in nude mice and reversed hyperglycemia more quickly in STZ-induced diabetic nude mice. Taken together, our findings highlighted the feasibility of constructing a pancreas-specific microenvironment based on proteomics and tissue engineering for the treatment of diabetes.

Notch signaling-induced cyclin d1 in diabetes ameliorating effects of the isolated polysaccharide from Rosa canina: In vitro and in vivo studies.

Notch signaling has a role in the expansion of the pancreas and the pathogenesis of diabetes. Modulation of Notch signaling by natural products seems to pave the way for treating diabetes. This research aimed to scrutinize the involvement of the Notch cascade in the diabetes-ameliorating effects of an isolated polysaccharide from Rosa canina. The isolated polysaccharide was characterized using Fourier transform infrared, nuclear magnetic resonance, high-performance gel-permeation chromatography, and liquid chromatography with tandem mass spectrometry techniques. Rat pancreatic β cells and STZ-induced diabetic rats were treated with the isolated polysaccharide. MTT assay, cell cycle analysis, quantative realtime-polymerase chain reaction, immunohistochemistry, and immunoblotting were used to reveal the growth and the expression levels of Notch1, DLL4, Jagged-1, hes1, Ins-1, Pdx-1, and cyclin d1 in treated and untreated pancreatic cells and tissues. The ameliorating effect of the polysaccharide in STZ-treated cells was accomplished by upregulation of cyclin d1 and hes1 as well as cell cycle progression. Notch inhibition by LY-411575 was associated with the downregulation of cyclin d1 which upregulates with polysaccharide treatment. The significant expression of cyclin d1 (90%) and nuclear expression of hes1 in the pancreas of the polysaccharide group were accompanied by improvement of hyperglycemia and associated biochemical factors as well as regeneration of islet cells as compared to untreated diabetic rats. Based on these findings, upregulation of Notch signaling-induced cyclin d1 could be proposed as the underlying diabetes-reducing effects of the isolated polysaccharide derivative implying that cyclin d1 actuation through activation of the Notch-DLL4 circuit may play the causal role in the treatment of diabetes.

Regulation of Pdx1 by oxidative stress and Nrf2 in pancreatic beta-cells.

The beta-cell identity gene, pancreatic duodenal homeobox 1 (Pdx1), plays critical roles in many aspects of the life of beta-cells including differentiation, maturation, function, survival and proliferation. High levels of reactive oxygen species (ROS) are extremely toxic to cells and especially to beta-cells due to their relatively low expression of antioxidant enzymes. One of the major mechanisms for beta-cell dysfunction in type-2 diabetes results from oxidative stress-dependent inhibition of PDX1 levels and function. ROS inhibits Pdx1 by reducing Pdx1 mRNA and protein levels, inhibiting PDX1 nuclear localization, and suppressing PDX1 coactivator complexes. The nuclear factor erythroid 2-related factor (Nrf2) antioxidant pathway controls the redox balance and allows the maintenance of high Pdx1 levels. Therefore, pharmacological activation of the Nrf2 pathway may alleviate diabetes by preserving Pdx1 levels.

Effect of hydroalcoholic seed extract of Nigella sativa on hepatic and pancreatic factors of Nrf2 and FGF21 in the regulation of insulin transcription factors of MafA and PDX-1 in streptozotocin-treated diabetic rats

IntroductionNigella sativa (N. sativa), one of the most commonly used medicinal herbs with antioxidant properties, increases blood insulin levels and lowers fasting blood sugar. Nuclear Erythroid Factor-Related Factor 2 (Nrf2) and Fibroblast Growth Factor 21 (FGF21) are two antioxidant factors that are increased by oxidative stress and hyperglycemia. The present study investigated how hydroalcoholic extract of N. sativa seed (HENS) increases blood insulin levels, taking into account changes in antioxidant factors and expression of insulin transcription factors.Materials and methodsTwo groups of male diabetic wistar rats were treated orally with HESN at doses of 200 and 400 mg/kg-body weight for one month. Fasting blood sugar (FBS) and insulin were measured using standard kits by photometric and ELISA methods, respectively. The expression levels of the Nrf2, FGF21 and β-Klotho genes as well as the insulin gene-stimulating transcription factors of MafA and PDX-1 were evaluated using real-time PCR. Oxidative stress was assessed by assessing serum total oxidation status (TOS), malondialdehyde (MDA), and total antioxidant capacity (TAC).ResultsHSEN showed a significant reducing effect on FBS and oxidative biomarkers and an increasing effect on serum insulin levels in treated diabetic rats compared to untreated diabetics (P < 0.05). The elevated levels of NRF2 and FGF21 in the liver and pancreas of the diabetic control group were significantly reduced after treatment with both HESN doses (P < 0.05). Following the ameliorative effects of HENS on pancreatic tissue and the reduction of oxidative stress, the expression level of MafA and PDX1 genes approached the level of these factors in healthy rats (P < 0.05).ConclusionThis study showed the therapeutic effects of HENS on diabetic pancreas by reducing oxidative stress and tissue damage, modifying the expression levels of PDX-1 and MafA genes, and regulating insulin secretion and blood glucose levels.

Molecular Mechanism of Pancreatic β-Cell Failure in Type 2 Diabetes Mellitus.

Various important transcription factors in the pancreas are involved in the process of pancreas development, the differentiation of endocrine progenitor cells into mature insulin-producing pancreatic β-cells and the preservation of mature β-cell function. However, when β-cells are continuously exposed to a high glucose concentration for a long period of time, the expression levels of several insulin gene transcription factors are substantially suppressed, which finally leads to pancreatic β-cell failure found in type 2 diabetes mellitus. Here we show the possible underlying pathway for β-cell failure. It is likely that reduced expression levels of MafA and PDX-1 and/or incretin receptor in β-cells are closely associated with β-cell failure in type 2 diabetes mellitus. Additionally, since incretin receptor expression is reduced in the advanced stage of diabetes mellitus, incretin-based medicines show more favorable effects against β-cell failure, especially in the early stage of diabetes mellitus compared to the advanced stage. On the other hand, many subjects have recently suffered from life-threatening coronavirus infection, and coronavirus infection has brought about a new and persistent pandemic. Additionally, the spread of coronavirus infection has led to various limitations on the activities of daily life and has restricted economic development worldwide. It has been reported recently that SARS-CoV-2 directly infects β-cells through neuropilin-1, leading to apoptotic β-cell death and a reduction in insulin secretion. In this review article, we feature a possible molecular mechanism for pancreatic β-cell failure, which is often observed in type 2 diabetes mellitus. Finally, we are hopeful that coronavirus infection will decline and normal daily life will soon resume all over the world.

Effect of Dachaihu decoction on traditional Chinese medicine-related indices of Type 2 diabetes in rats, and elucidation of its mechanism of action

Purpose: To study the influence of Dachaihu decoction on traditional Chinese medicine (TCM)-related indices of type 2 diabetes mellitus (T2DM) in rats, and the likely mechanism involved.&#x0D; Methods: Forty-five healthy male SD rats were randomly selected and used to establish T2DM rat model. The rats were randomly assigned to 3 groups: control, model and Dachaihu decoction groups (n = 15). Fasting blood glucose (FBG), glycosylated hemoglobin (HbAlc), free fatty acids (FFAs), total cholesterol (TC) and oxidative stress were measured. Pathological changes in rats in each group were monitored, and mRNA levels of PDX-1 and MaFA in pancreatic tissue were measured.&#x0D; Results: The levels of FBG, HbAlc, FFA, TC, MDA and ROS in the Dachaihu decoction group were significantly decreased, while SOD, PDX-1 mRNA and MafA mRNA were markedly raised, relative to control (p &lt; 0.05). In the Dachaihu decoction group, the rats had pink paws; their noses and tongues were glossy and moist, and there was more physical activity, relative to model rats (p &lt; 0.05).&#x0D; Conclusion: These results indicate that Dachaihu decoction is effective against T2DM in rats. The mechanisms of action may be by inhibition of oxidative stress, improvement of the function of islet beta cells, and mitigation of symptoms of fatigue and dehydration. Therefore, Dachaihu decoction may be useful for adjuvant treatment of TCM-T2DM but clinical studies are required to ascertain this.

Synthetic Small Molecules Induce Insulin Secretion and Pancreatic Beta-Cell-Specific Gene Expression

Despite various efficient pharmaceuticals which are already used to manage diabetes, new drugs are needed to preserve and restore the function of pancreatic β-cells (pβCs) including cell-specific gene expression and insulin production and secretion. Newly developed small molecules (SMs) with potential anti-diabetic activity need to be preliminarily tested. Mice insulinoma MIN6 cells can be utilized as an in vitro screening model. These cells have pβC characteristics and can secrete insulin in response to glucose level changes. As well, the β-cell-specific gene expression pattern of these cells is similar to that of mouse pancreatic islet cells. It is possible to use this cell line as a research tool to study the function of pβCs. To date, approximately 60 genes have been identified which are effective in the pβC embryonic development and insulin production and secretion during puberty, including pancreas/duodenum homeobox protein 1 (Pdx1), neuronal differentiation 1 (Neurod1), neurogenin3 (Ngn3), and insulin-1 precursor (Ins1). In this study, a family of new SMs that are structurally similar to glinides was synthesized through 3 different synthetic methods and categorized into 3 categories (C1–C3). Then, these novel SMs were characterized by testing their effects on cell viability, pβC-specific gene expression, and insulin secretion in MIN6 in 4 different concentrations and at 3 time points (24, 48, and 72 h). According to our results, SMs of C1 (1j, 1k, and 1l) and 2 SMs of C3 (1f, 1i), at 200 μM concentration, were able to increase the expression levels of Pdx1, Neurod1, Ngn3, and Ins1 as well as the insulin secretion after 24 h. However, C2 (1a, 1b, 1c, and 1d) did not show significant bioactivity of MIN6 cells. These investigated molecules can provide a tool for exploring pseudo-islet functionality in MIN6 cells or provide a possible basis for future therapeutic interventions for diabetes.

MiR-200b-3p Induces the Formation of Insulin-Producing Cells from Umbilical Cord Mesenchymal Stem Cells by Targeting ZEB2.

Studies have reported that miRNAs regulate β-cell differentiation, pancreatic development, and insulin secretion. However, the biological function of miRNAs during the formation of insulin-producing cells (IPCs) from umbilical cord-derived mesenchymal stem cells (UCMSCs) is poorly understood. Herein, the role and mechanism of miR-200b-3p during UCMSC differentiation into IPCs were investigated. UCMSCs were induced for IPC differentiation. An animal model was established by transplanting UCMSC-derived IPCs into streptozotocin-induced diabetic mice. Cell surface markers of undifferentiated UCMSCs and the expression of proinsulin and Pdx-1 in UCMSC-derived IPCs were measured by flow cytometry analysis. The interaction between miR-200b-3p and zinc finger E-box binding homeobox 2 (ZEB2) 3' untranslated region (UTR) was confirmed by luciferase reporter assay. Insulin secretion in UCMSC-derived IPCs was measured by enzyme-linked immunosorbent assay (ELISA). Islet marker (insulin and Pdx-1) levels were evaluated using immunofluorescence staining. In this study, undifferentiated UCMSCs had MSC phenotype and the potential for osteogenesis and adipogenesis. UCMSC-derived IPCs displayed glucose responsive insulin secretion and expressed insulin, Pdx-1 and proinsulin. miR-200b-3p was overexpressed in UCMSC-derived IPCs. Mechanically, miR-200b-3p targeted ZEB2. ZEB2 knockdown reversed the inhibitory effect of miR-200b-3p downregulation on IPC differentiation from UCMSCs in vitro. Moreover, miR-200b-3p silencing inhibited the anti-hypoglycemic effects and insulinogenesis of UCMSC-derived IPCs grafts in the kidney capsule of diabetic mice. Overall, miR-200b-3p induces the formation of IPCs from UCMSCs by targeting ZEB2.

Modulation of Notch signaling and angiogenesis via an isolated polysaccharide from Momordica charantia in diabetic rats.

Given the impact of notch signaling in the modulation of metabolic diseases and normal tissue homeostasis, this study aimed to evaluate whether notch signaling has a role in anti-diabetic and islet regenerative effects of the isolated polysaccharide from Momordica charantia in diabetic rats. The polysaccharide was isolated from M. charantia (MCP) and was characterized by using FTIR and LC-MS/MS. The diabetic model was established by intraperitoneal administration of streptozotocin in male Wistar rats and grouped into control, diabetic, metformin (500mgkg-1 day-1 ), and treatment (10mgkg-1 day-1 ) groups. The levels of Hes1, Notch 1, DLL4, Jagged1, Pdx1, CD34, CD31, and VEGF were analyzed by using immunohistochemistry and real-time PCR. Structural analyses have revealed the polysaccharide structure of the isolated fraction. High blood glucose was normalized by MCP treatment in diabetic rats. MCP scaled up the mRNA levels of Ins1, jagged1, Pdx1, and Hes1 while it scaled down the levels of Notch1, Dll4, and the ratio of Bax/Bcl2 in diabetic rats. Furthermore, the immunohistochemistry staining levels of hes1, cyclin d1, and VEGF proteins were increased in the pancreas of MCP-treated diabetic rats compared to the diabetic group. These findings provide insights into the anti-diabetic potential of MCP through modulation of islets' regeneration and suggest that modulation of notch and angiogenesis pathways may play a pivotal role in the restoration of the islets to relieve diabetes. PRACTICAL APPLICATIONS: Polysaccharides extracted from Momordica charantia could normalize the level of blood glucose in STZ-induced type 2 diabetic rats through modulation of notch and angiogenesis singling pathways. Given that this effect was associated with the increased expression of Pdx-1 and Insulin in the pancreas, the isolated polysaccharide is expected to be introduced as a convenient medicine in the treatment of diabetes through modulation of β-cell regeneration.