Islet Growth Research Articles

In Situ Growth of Suspended Zirconene Islets Inside Graphene Pores

AbstractExperiments using a transmission electron microscope decomposed zirconium acetylacetonate with an electron beam, forming zirconium nanoparticles on graphene. Continued electron irradiation transformed these nanoparticles into atomically thick zirconium islets (zirconene islets) within the graphene lattice. The electron beam caused zirconium atom dislocations and vacancies that are rapidly refilled, a process repeating until the vacancies evolved into zirconium nanoribbons before breaking. This study offers insights into the electron‐driven growth and degradation of zirconene islets, showcasing a method to fabricate freestanding zirconenes for use as atomically thin coatings in extreme environments.

Liraglutide on type 2 diabetes mellitus with nonalcoholic fatty liver disease: A systematic review and meta-analysis of 16 RCTs.

Nonalcoholic fatty liver disease (NAFLD) is a common comorbidity of type 2 diabetes mellitus (T2DM). Our aim is to investigate the effects of liraglutide on T2DM with NAFLD. Relevant articles published from the earliest publication to March 2022 were selected from several databases. The Cochrane Collaboration's RevMan software was used for the analysis. Sixteen studies are selected for this meta-analysis, which includes totally 634 patients in the treatment group and 630 patients in the control group. As a result, 14 studies show that fasting plasma glucose levels of the experimental group are lower than that of the control group; 15 studies show that glycosylated hemoglobin A1c levels of the experimental group are lower than that of the control group; 13 studies show that triglyceride levels of the experimental group are lower than that of the control group; twelve studies show that total cholesterol levels of the experimental group are lower than that of the control group; 10 studies show that alanine aminotransferase levels of the experimental group is lower than that of the control group; 10 studies show that no significant difference in changes in aspartate transaminase between 2 groups; 13 studies show that low density lipoprotein cholesterol levels of the experimental group is lower than that of the control group; 9 studies show that no significant difference in changes in high density lipoprotein cholesterol between 2 groups; 7 studies mentioned adverse effects and the difference is significant. Liraglutide is potentially curative for T2DM with NAFLD.

Pancreas Whole Tissue Transcriptomics Highlights the Role of the Exocrine Pancreas in Patients With Recently Diagnosed Type 1 Diabetes.

Although type 1 diabetes (T1D) is primarily a disease of the pancreatic beta-cells, understanding of the disease-associated alterations in the whole pancreas could be important for the improved treatment or the prevention of the disease. We have characterized the whole-pancreas gene expression of patients with recently diagnosed T1D from the Diabetes Virus Detection (DiViD) study and non-diabetic controls. Furthermore, another parallel dataset of the whole pancreas and an additional dataset from the laser-captured pancreatic islets of the DiViD patients and non-diabetic organ donors were analyzed together with the original dataset to confirm the results and to get further insights into the potential disease-associated differences between the exocrine and the endocrine pancreas. First, higher expression of the core acinar cell genes, encoding for digestive enzymes, was detected in the whole pancreas of the DiViD patients when compared to non-diabetic controls. Second, In the pancreatic islets, upregulation of immune and inflammation related genes was observed in the DiViD patients when compared to non-diabetic controls, in line with earlier publications, while an opposite trend was observed for several immune and inflammation related genes at the whole pancreas tissue level. Third, strong downregulation of the regenerating gene family (REG) genes, linked to pancreatic islet growth and regeneration, was observed in the exocrine acinar cell dominated whole-pancreas data of the DiViD patients when compared with the non-diabetic controls. Fourth, analysis of unique features in the transcriptomes of each DiViD patient compared with the other DiViD patients, revealed elevated expression of central antiviral immune response genes in the whole-pancreas samples, but not in the pancreatic islets, of one DiViD patient. This difference in the extent of antiviral gene expression suggests different statuses of infection in the pancreas at the time of sampling between the DiViD patients, who were all enterovirus VP1+ in the islets by immunohistochemistry based on earlier studies. The observed features, indicating differences in the function, status and interplay between the exocrine and the endocrine pancreas of recent onset T1D patients, highlight the importance of studying both compartments for better understanding of the molecular mechanisms of T1D.

Oxytocin signal contributes to the adaptative growth of islets during gestation.

BackgroundIncreased insulin production and secretion by pancreatic β-cells are important for ensuring the high insulin demand during gestation. However, the underlying mechanism of β-cell adaptation during gestation or gestational diabetes mellitus (GDM) remains unclear. Oxytocin is an important physiological hormone in gestation and delivery, and it also contributes to the maintenance of β-cell function. The aim of this study was to investigate the role of oxytocin in β-cell adaptation during pregnancy.MethodsThe relationship between the blood oxytocin level and pancreatic β-cell function in patients with GDM and healthy pregnant women was investigated. Gestating and non-gestating mice were used to evaluate the in vivo effect of oxytocin signal on β-cells during pregnancy. In vitro experiments were performed on INS-1 insulinoma cells.ResultsThe blood oxytocin levels were lower in patients with GDM than in healthy pregnant women and were associated with impaired pancreatic β-cell function. Acute administration of oxytocin increased insulin secretion in both gestating and non-gestating mice. A 3-week oxytocin treatment promoted the proliferation of pancreatic β-cells and increased the β-cell mass in gestating but not non-gestating mice. Antagonism of oxytocin receptors by atosiban impaired insulin secretion and induced GDM in gestating but not non-gestating mice. Oxytocin enhanced glucose-stimulated insulin secretion, activated the mitogen-activated protein kinase pathway, and promoted cell proliferation in INS-1 cells.ConclusionsThese findings provide strong evidence that oxytocin is needed for β-cell adaptation during pregnancy to maintain β-cell function, and the lack of oxytocin could be associated with the risk of GDM.

Loss of growth hormone signaling in the mouse germline or in adulthood reduces islet mass and alters islet function with notable sex differences.

In the endocrine pancreas, growth hormone (GH) is known to promote pancreatic islet growth and insulin secretion. In this study, we show that GH receptor (GHR) loss in the germline and in adulthood impacts islet mass in general but more profoundly in male mice. GHR knockout (GHRKO) mice have enhanced insulin sensitivity and low circulating insulin. We show that the total cross-sectional area of isolated islets (estimated islet mass) was reduced by 72% in male but by only 29% in female GHRKO mice compared with wild-type controls. Also, islets from GHRKO mice secreted ∼50% less glucose-stimulated insulin compared with size-matched islets from wild-type mice. We next used mice with a floxed Ghr gene to knock down the GHR in adult mice at 6 mo of age (6mGHRKO) and examined the impact on glucose and islet metabolism. By 12 mo of age, female 6mGHRKO mice had increased body fat and reduced islet mass but had no change in glucose tolerance or insulin sensitivity. However, male 6mGHRKO mice had nearly twice as much body fat, substantially reduced islet mass, and enhanced insulin sensitivity, but no change in glucose tolerance. Despite large losses in islet mass, glucose-stimulated insulin secretion from isolated islets was not significantly different between male 6mGHRKO and controls, whereas isolated islets from female 6mGHRKO mice showed increased glucose-stimulated insulin release. Our findings demonstrate the importance of GH to islet mass throughout life and that unique sex-specific adaptations to the loss of GH signaling allow mice to maintain normal glucose metabolism.NEW & NOTEWORTHY Growth hormone (GH) is important for more than just growth. GH helps to maintain pancreatic islet mass and insulin secretion throughout life. Sex-specific adaptations to the loss of GH signaling allow mice to maintain normal glucose regulation despite losing islet mass.

IPSCs-laden GDF8-grafted aldehyde hyaluronic acid-polyacrylamide inverted colloidal crystal constructs with controlled release of CHIR99021 and retinoic acid to generate insulin-producing cells

Recent advances in attempting maturation of pancreatic β cells derived from induced pluripotent stem cells (iPSCs) have initiated a gateway to developing innovated materials and protocols for artificial pancreas implantation in diabetic management. In this study, we proposed a tissue-engineering scheme using iPSCs-laden aldehyde hyaluronic acid (AHA)-polyacrylamide (PAAM) inverted colloidal crystal constructs (ICCCs) associated with controlled release of induction molecules to generate insulin-producing cells (IPCs). Based on physicochemical properties, AHA-PAAM inverted colloidal crystal scaffolds (ICCSs) at a 1:1 weight ratio of AHA to PAAM were used, modified with growth and differentiation factor 8, and grafted with CHIR99021-loaded solid lipid nanoparticles (CHIR99021-SLNs-GDF8-AHA-PAAM ICCSs) to differentiate iPSCs into definitive endoderm (DE) cells. Induction with fibroblast growth factor 7-grafted retinoic acid-loaded SLNs (FGF7-RA-SLNs) further differentiated DE cells into insulin-producing cells (IPCs) in the constructs. An introduction of sustained delivery facilitated bioavailability of CHIR99021 and RA during DE and islet formation, and yielded a high quantity of secreted insulin from IPCs after stimulation of glucose. Loaded CHIR99021 and grafted FGF7 acted as supporters to promote the main function of grafted GDF8 and loaded RA in DE and islet growth. From the highest expression of pancreatic and duodenal homeobox 1, we have reached the appropriate concentration of GDF8, CHIR99021, RA and FGF7 for regenerating IPCs. These data showed that the 2-stage guided differentiation of iPSCs into IPCs in CHIR99021-SLNs-GDF8-AHA-PAAM ICCSs can be promising in ameliorating insulin secretion by β-cell regeneration.

Beta-cell β1 integrin deficiency affects in utero development of islet growth and vascularization.

The β1 integrin subunit contributes to pancreatic beta cell growth and function through communication with the extracellular matrix (ECM). The effects of in vitro and in vivo β1 integrin knockout have been extensively studied in mature islets, yet no study to date has examined how the loss of β1 integrin during specific stages of pancreatic development impacts beta cell maturation. Beta-cell-specific tamoxifen-inducible Cre recombinase (MIP-CreERT) mice were crossed with mice containing floxed Itgb1 (β1 integrin) to create an inducible mouse model (MIPβ1KO) at the second transition stage (e13.5)of pancreas development. By e19.5-20.5, the expression of beta-cell β1 integrin in fetal MIPβ1KO mice was significantly reduced and these mice displayed decreased beta cell mass, density and proliferation. Morphologically, fetal MIPβ1KO pancreata exhibited reduced islet vascularization and nascent endocrine cells in the ductal region. In addition, decreased ERK phosphorylation was observed in fetal MIPβ1KO pancreata. The expression of transcription factors needed for beta-cell development was unchanged in fetal MIPβ1KO pancreata. The findings from this study demonstrate that β1 integrin signaling is required during a transition-specific window in the developing beta-cell to maintain islet mass and vascularization.

Growth of islet carbon coating on nitrogen-activated polyurethane surface

Development of discontinuous (islet) plasma coatings is of interest in the design of materials with non-uniform (selective) surface properties. In comparison with similar continuous coatings, they are more resistant to a damage induced by deformation of an elastic substrate. In this work, a formation of carbon islet coating obtained by a pulsed magnetron sputtering of a graphite target on the surface of nitrogen-activated elastic polyurethane is studied. Roughness, stiffness and surface energy of the polymer substrate are increased after the activation. High surface energy makes possible the adhesion of carbon islets (the size is ~100 μm and the thickness is 4…30 nm). The structure of such coatings depends both on the activation time and on the number of pulses of the magnetron discharge. At the initial stage of formation, the islets consist of individual shards ~1 μm in plane, further carbon deposition covers them by a continuous layer. Certain areas of the islets with a thickness > 10 nm have an inhomogeneous wrinkled surface. The folds are formed at the initial stage of the islet growth, and the subsequent carbon deposition flattens them. Preliminary studies of stretched samples up to 20% showed good fracture toughness of the given coatings.

2148-P: Islet Endocrine Cells Shows a Unique Pattern on Development and Growth of Each Cell Type in Human Subjects

Development and growth of islet endocrine cell volume are assumed to mainly depend on cell proliferation. In addition, the partial contribution of islet neogenesis and chromogranin A positive hormone negative cell (CPHN cell) is recently clarified. Detailed evaluation for the islet cell development and growth, however, is not well explored linking to the change of cell replication, neognesis and CPHN cell for each type of endocrine cells in human specimens. For this purpose, we recruited human autopsied pancreata, aged from 24 weeks old to 19 years old (n=32). Formalin-fixed paraffin embedded sections from pancreatic body were used for immunohistochemistry (IHC) and immunofluorescence (IF) analysis. The subjects were divided into 4 groups, Fetus (F: 24-31 weeks), Infant (I : 0-1 years), Child (C : 2-12 years) and Adolescence (A : 13-19 years). Quintuple-IHC with antibodies for glucagon, insulin, somatostatin, pp and Ki-67 was performed for the measurement of islet cell volume density (V) and replication status. Vαand Vβwere increased with age. Vβin A was more abundant than in F (p<0.01). On the other hand, Vδnegatively correlated with age (r=-0.701, p<0.01) and was more in F than in C and A (p<0.01). Ki-67 positive index for αand δ cells showed the highest in F (p<0.01), whereas that of β cells was the highest in I (p<0.01). Neogenic islet density, evaluated in IHC with an antibody for chromogranin A, showed negative correlation with age (r=-0.608, p<0.01). Double-IF with a cocktail of four kinds of antibodies for islet hormones and for chromogranin A was performed to evaluate VCPHN. CPHN cell was identified in both islets and neogenic islets. VCPHNwas more abundant in neogenic islets of F and I than those of C and A. Our results suggest that each kind of islet cell owns a unique pattern of the cell development and growth. In particular, neogenic islet and CPHN cell may play a role as the source of βcells in the later life. Disclosure S. Osonoi: None. H. Mizukami: None. K. Takahashi: None. K. Kudo: None. S. Yagihashi: None.

Chronic maternal inflammation during late gestation impairs subsequent β-cell function but not islet growth in fetal sheep.

Intrauterine growth restriction (IUGR) greatly increases perinatal mortality and morbidity rates, and leads to much greater risk for metabolic complications later in life. One such complication is the development of glucose intolerance or diabetes, which typically develops concurrently with abhorrent patterns of insulin secretions due to diminished β-cell mass and impaired function as well as an overall reduction in pancreatic endocrine tissue. The mechanisms by which IUGR causes problems with health and function of the pancreatic islets are not well understood. Therefore, our goal for this study was to determine how materno-fetal inflammation (MI) affects β-cell growth and function. To do this, we compared the average islet areas, plasma insulin concentrations, and blood glucose concentrations between MI-IUGR fetal lambs (n = 7) and control fetal lambs (n = 7). Pregnant ewes were injected with saline (controls) or 0.1-µg/kg bacterial lipopolysaccharide (LPS) every 3 d from days 100 to 115 of gestation (term = 150 d). Throughout late gestation, arterial blood of the fetus was periodically drawn and analyzed for plasma insulin (ELISA) and blood glucose (ABL90 FLEX) levels. On day 125 of gestation, ewes were euthanized and fetal pancreas was extracted. Sections of the fetal pancreas were then fixed in 4% paraformaldehyde, sectioned (cryostat) at a thickness of 8 µm, stained for insulin-positive area, and imaged on 20x magnification for analysis of average islet area. Between MI-IUGR and control fetuses, there were no differences in average islet areas (1675 ± 286 and 1678 ± 287 µm2, respectively), which indicates that MI did not impair growth and physical development of fetal islets. In addition, blood glucose was similar in all fetuses. However, results showed less (P ≤ 0.05) plasma insulin concentration in MI-IUGR fetuses (0.39 ± 0.07 ng/mL) than in controls (0.70 ± 0.09 ng/mL). This indicates impaired β-cell functional capacity in MI-IUGR fetuses despite normal growth, which is quantified by a tendency (P = 0.08) for strong positive correlation (r = 0.91) between plasma insulin and islet area in control fetuses but an absence of correlation in MI-IUGR fetuses. From this study, we can conclude that MI-IUGR has no effect on the growth and physical development of β cells; however, it does greatly affect their function.

“Alarming" T-Regulatory Cells (Tregs) to Protect from Type 1 Diabetes (T1D)

Defects in IL-2 signaling and Tregs correlate with susceptibility to T1D. Helminth burden also negatively correlates with the incidence of T1D. The alarmin IL-33 and its receptor ST2 are elicited in anti-helminth immunity, which also increase Tregs, M2 macrophages and Th2 response. We hypothesized that IL-33 may cooperate with IL-2 in promoting Tregs to protect from T1D. Indeed, a major subset of Tregs express ST2, thus enabling a role for IL-33 in Treg biology. Non-obese diabetic (NOD) mice, which have less Tregs than the nondiabetic NOD.Idd3 congenic mice, also exhibit less ST2+ Tregs (13±3%) than NOD.Idd3 (38±11%). For better cooperativity and preferential targeting of Tregs, we generated a hybrid cytokine (IL233) bearing IL-2 and IL-33 activities in a single molecule. Recent-hyperglycemia onset NOD mice (n≥6/group) were treated with daily injections (3.3pmol/g) of IL-2 and/or IL-33 or IL233 for 5 days. IL-33 alone offered a similar, if not better reversal of T1D with a 70% cumulative incidence (CI) compared to IL-2 alone (80% CI), whereas IL233 offered the best protection with 50% of mice remaining in remission 10-weeks post-treatment. There was a robust increase in the proportion of Tregs in pancreatic lymph node in IL233 group (25±3.7%) compared to 10±3.9%, 16±4.1%, 14±4.3% and 19±4.3% in Saline, IL-2 only, IL-33 only and IL-2 and IL-33 groups respectively. IL233 treatment also increased the levels of Tregs and group-2 innate lymphoid cells in an alternate species (rats) and blocked high-dose streptozotocin (STZ)-induced beta-cell death. Interestingly, the average islet size was bigger in the rats treated with IL233 in the STZ model, indicating a role of IL233 in islet growth and repair. Thus, IL233 utilizes the synergy of IL-2 and IL-33 to promote Tregs and bears strong therapeutic potential for T1D. Disclosure R. Sharma: None. V. Sabapathy: None.

SAD-A Promotes Pancreatic ß-Cell Proliferation by Regulating ß-Cell Cycle as a Downstream Target of mTORC1 Signaling

Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and β-cell dysfunction, which leads to the depletion of β-cell mass. Understanding the molecular mechanisms driving islet β-cell dysfunction is paramount for developing therapies to increase β-cell function. The mammalian target of rapamycin complex 1 (mTORC1) plays a key role in regulating β-cell function by integrating growth factors and mitogens to direct cell cycle and survival; yet, mechanistically this process is not fully understood. Synapses of amphids defective protein kinase A (SAD-A) is a member of AMP-activated protein kinase (AMPK)-related family kinases, with high expression in the pancreas. My earlier work demonstrated that SAD-A is a β-cell specific mediator of insulin secretion and islet β-cell size. Furthermore, glucose dramatically stimulated SAD-A protein translation in islets that was potently inhibited by rapamycin, an inhibitor of mTORC1. My recent preliminary studies showed that 1) SAD-A overexpression increases β-cell proliferation in the MIN6 β-cell line and islets; 2) Ablation of SAD-A in pancreas of mice (pSADKO) promotes β-cell apoptosis and attenuates compensatory islet growth in obese mice; 3) SAD-A depletion in the pancreas increases mRNA expression of cyclin D2 in islets of pSADKO mice. Based on these observations, I hypothesize that SAD-A promotes pancreatic β-cell proliferation by regulating β-cell cycle as a downstream target of mTORC1 signaling. Disclosure J. Nie: None. N. Musi: None. Y. Shi: None.

Different developmental histories of beta-cells generate functional and proliferative heterogeneity during islet growth

The proliferative and functional heterogeneity among seemingly uniform cells is a universal phenomenon. Identifying the underlying factors requires single-cell analysis of function and proliferation. Here we show that the pancreatic beta-cells in zebrafish exhibit different growth-promoting and functional properties, which in part reflect differences in the time elapsed since birth of the cells. Calcium imaging shows that the beta-cells in the embryonic islet become functional during early zebrafish development. At later stages, younger beta-cells join the islet following differentiation from post-embryonic progenitors. Notably, the older and younger beta-cells occupy different regions within the islet, which generates topological asymmetries in glucose responsiveness and proliferation. Specifically, the older beta-cells exhibit robust glucose responsiveness, whereas younger beta-cells are more proliferative but less functional. As the islet approaches its mature state, heterogeneity diminishes and beta-cells synchronize function and proliferation. Our work illustrates a dynamic model of heterogeneity based on evolving proliferative and functional beta-cell states.

The impact of IUGR on pancreatic islet development and β-cell function.

Placental insufficiency is a primary cause of intrauterine growth restriction (IUGR). IUGR increases the risk of developing type 2 diabetes mellitus (T2DM) throughout life, which indicates that insults from placental insufficiency impair β-cell development during the perinatal period because β-cells have a central role in the regulation of glucose tolerance. The severely IUGR fetal pancreas is characterized by smaller islets, less β-cells, and lower insulin secretion. Because of the important associations among impaired islet growth, β-cell dysfunction, impaired fetal growth, and the propensity for T2DM, significant progress has been made in understanding the pathophysiology of IUGR and programing events in the fetal endocrine pancreas. Animal models of IUGR replicate many of the observations in severe cases of human IUGR and allow us to refine our understanding of the pathophysiology of developmental and functional defects in islet from IUGR fetuses. Almost all models demonstrate a phenotype of progressive loss of β-cell mass and impaired β-cell function. This review will first provide evidence of impaired human islet development and β-cell function associated with IUGR and the impact on glucose homeostasis including the development of glucose intolerance and diabetes in adulthood. We then discuss evidence for the mechanisms regulating β-cell mass and insulin secretion in the IUGR fetus, including the role of hypoxia, catecholamines, nutrients, growth factors, and pancreatic vascularity. We focus on recent evidence from experimental interventions in established models of IUGR to understand better the pathophysiological mechanisms linking placental insufficiency with impaired islet development and β-cell function.

Two different protein expression profiles of oral squamous cell carcinoma analyzed by immunoprecipitation high-performance liquid chromatography

BackgroundOral squamous cell carcinoma (OSCC) is one of the most dangerous cancers in the body, producing serious complications with individual behaviors. Many different pathogenetic factors are involved in the carcinogenesis of OSCC. Cancer cells derived from oral keratinocytes can produce different carcinogenic signaling pathways through differences in protein expression, but their protein expression profiles cannot be easily explored with ordinary detection methods.MethodsThe present study compared the protein expression profiles between two different types of OSCCs, which were analyzed through immunoprecipitation high-performance liquid chromatography (IP-HPLC).ResultsTwo types of squamous cell carcinoma (SCC) occurred in a mandibular (SCC-1) and maxillary gingiva (SCC-2), but their clinical features and progression were quite different from each other. SCC-1 showed a large gingival ulceration with severe halitosis and extensive bony destruction, while SCC-2 showed a relatively small papillary gingival swelling but rapidly grew to form a large submucosal mass, followed by early cervical lymph node metastasis. In the histological observation, SCC-1 was relatively well differentiated with a severe inflammatory reaction, while SCC-2 showed severely infiltrative growth of each cancer islets accompanied with a mild inflammatory reaction. IP-HPLC analysis revealed contrary protein expression profiles analyzed by 72 different oncogenic proteins. SCC-1 showed more cellular apoptosis and invasive growth than SCC-2 through increased expression of caspases, MMPs, p53 signaling, FAS signaling, TGF-β1 signaling, and angiogenesis factors, while SCC-2 showed more cellular growth and survival than SCC-1 through the increased expression of proliferating factors, RAS signaling, eIF5A signaling, WNT signaling, and survivin.ConclusionsThe increased trends of cellular apoptosis and invasiveness in the protein expression profiles of SCC-1 were implicative of its extensive gingival ulceration and bony destruction, while the increased trends of cellular proliferation and survival in the protein profile of SCC-2 were implicative of its rapid growing tumor mass and early lymph node metastasis. These analyses of the essential oncogenic protein expression profiles in OSCC provide important information for genetic counseling or customized gene therapy in cancer treatment. Therefore, protein expression profile analysis through IP-HPLC is helpful not only for the molecular genetic diagnosis of cancer but also in identifying target molecules for customized gene therapy in near future.

Anti-TCRβ mAb in Combination With Neurogenin3 Gene Therapy Reverses Established Overt Type 1 Diabetes in Female NOD Mice.

Insulin-producing β cells in patients with type 1 diabetes (T1D) are destroyed by T lymphocytes. We investigated whether targeting the T-cell receptor (TCR) with a monoclonal antibody (mAb) abrogates T-cell response against residual and newly formed islets in overtly diabetic nonobese diabetic (NOD) mice. NOD mice with blood glucose levels of 250 to 350 mg/dL or 350 to 450 mg/dL were considered as new-onset or established overt diabetes, respectively. These diabetic NOD mice were transiently treated with an anti-TCR β chain (TCRβ) mAb, H57-597, for 5 days. Two weeks later, some NOD mice with established overt diabetes further received hepatic gene therapy using the islet-lineage determining gene Neurogenin3 (Ngn3), in combination with the islet growth factor gene betacellulin (Btc). We found that anti-TCRβ mAb (50 µg/d) reversed >80% new-onset diabetes in NOD mice for >14 weeks by reducing the number of effector T cells in the pancreas. However, anti-TCRβ mAb therapy alone reversed only ∼20% established overt diabetes in these mice. Among those overtly diabetic NOD mice whose diabetes was resistant to anti-TCRβ mAb treatment, ∼60% no longer had diabetes when they also received Ngn3-Btc hepatic gene transfer 2 weeks after initial anti-TCRβ mAb treatment. This combination of Ngn3-Btc gene therapy and anti-TCRβ mAb treatment induced the sustained formation of periportal insulin-producing cells in the liver of overtly diabetic mice. Therefore, directly targeting TCRβ with a mAb potently reverses new-onset T1D in NOD mice and protects residual and newly formed gene therapy-induced hepatic neo-islets from T-cell‒mediated destruction in mice with established overt diabetes.

Prolactin and oleic acid synergistically stimulate β-cell proliferation and growth in rat islets

ABSTRACTIslet adaptation to pregnancy is largely influenced by prolactin and placental lactogens. In addition serum lipids are significantly increased. Here, we report the novel observation that prolactin and oleic acid synergistically stimulate islet cell proliferation and islet growth. In neonatal rat islets, prolactin increased proliferation 6-fold, oleic acid 3.5-fold, and their combination 15-fold. The expression of insulin in these dividing cells establishes them as β-cells. Similar changes were seen in islet growth. This synergy is restricted to monounsaturated fatty acids and does not occur with other islet growth factors. Oleic acid increases prolactin-induced STAT5 phosphorylation, even though by itself it is unable to induce STAT5 phosphorylation. Their effects on Erk1/2 phosphorylation are additive. Some of the synergy requires the formation of oleoyl CoA and/or its metabolites. Unexpectedly, methyl oleic acid, a non-metabolizable analog of oleic acid, also shows synergy with prolactin. In summary, prolactin and oleic acid synergistically stimulate islet cell proliferation and islet growth in rat islets, oleic acid increases prolactin-induced STAT5 activation, and requires both the metabolism of oleic acid and non-metabolized oleic acid. Since oleic acid is the most abundant monounsaturated fatty acid in serum that is elevated during pregnancy, it may contribute to increased β-cell proliferation seen during pregnancy.

Reg proteins promote acinar-to-ductal metaplasia and act as novel diagnostic and prognostic markers in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignant tumor. Acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) are both precursor lesions that lead to the development of PDAC. Reg family proteins (Reg1A, 1B, 3A/G, 4) are a group of calcium-dependent lectins that promote islet growth in response to inflammation and/or injuries. The aim of this study was to establish a role for Reg proteins in the development of PDAC and their clinical value as biomarkers. We found that Reg1A and Reg3A/G were highly expressed in the ADM tissues by immunohistochemistry. In the 3-dimensional culture of mouse acinar cells, Reg3A promoted ADM formation with concurrent activation of mitogen-acitvated protein kinase. Upregulation of Reg1A and Reg1B levels was observed as benign ductal epithelium progresses from PanIN to invasive PDAC. Patients with PDAC showed significantly higher serum levels of Reg1A and Reg1B than matching healthy subjects. These results were further validated by the quantification of Reg 1A and 1B mRNA levels in the microdissected tissues (22- and 6-fold increases vs. non-tumor tissues). Interestingly, patients with higher levels of Reg1A and 1B exhibited improved survival rate than those with lower levels. Furthermore, tissue expressions of Reg1A, Reg1B, and Reg4 could differentiate metastatic PDAC in the liver from intrahepatic cholangiocarcinoma with 92% sensitivity and 95% specificity. Overall, our results demonstrate the upregulation of Reg proteins during PDAC development. If validated in larger scale, Reg1A and Reg1B could become clinical markers for detecting early stages of PDAC, monitoring therapeutic response, and/or predicting patient's prognosis.

Plasma electrolytic oxide layers as promising systems for catalysis

Abstract The paper overviews the various approaches for obtaining the metal-supported PEO layers with a developed surface. They are following: (1) pre-etching the metal surfaces, (2) using the electrolytes in which linear discharges are realized under certain conditions of PEO processing, (3) the use of oxide-forming electrolytes for obtaining ornamental structures, (4) applying the electrolytes with isopoly and heteropoly anions in which islet growth of coral-like structures is possible. It is shown that changing the composition and pH of the electrolyte, the electrical parameters of PEO processing you can control the sizes of surface relief fragments such as pores, micro- and nanostructures and create conditions for the formation of developed surface and secondary layers. Using PEO structures as a substrate for subsequent deposition of the catalytically active components by methods of impregnation, extraction, and sol-gel synthesis allows one to form the developed surfaces with nanowires, nanospheres, hedgehog-like structures too. Application of the discussed methods may improve the efficiency of catalysts formed using PEO technology.

Deteriorated high-fat diet-induced diabetes caused by pancreatic β-cell-specific overexpression of Reg3β gene in mice.

Reg family proteins have long been implicated in islet β-cell proliferation, survival, and regeneration. In our previous study, we reported that Reg3β overexpression did not increase islet growth but prevented streptozotocin-induced islet damage by inducing specific genes. In order to explore its role in type 2 diabetes (T2D), we established high-fat diet (HFD)-induced obesity and diabetes in RIP-I/Reg3β mice. Glucose and insulin tolerance tests, immunofluorescence for insulin, eIF2α, and GLUT2 in islets, Western blots on phosphorylated AMPKα and hepatic histology were performed. Both RIP-I/Reg3β and wild-type mice gained weight rapidly and became hyperglycemic after 10weeks on the HFD. However, the transgenic mice exhibited more significant acceleration in blood glucose levels, further deterioration of glucose intolerance and insulin resistance, and a lower intensity of insulin staining. Immunofluorescence revealed similar magnitude of islet compensation to awild-type HFD. The normal GLUT2 distribution in the transgenic β-cells was disrupted and the staining was obviously diminished on the cell membrane. HFD feeding also caused a further decrease in the level of AMPKα phosphorylation in the transgenic islets. Our results suggest that unlike its protective effect against T1D, overexpressed Reg3β was unable to protect the β-cells against HFD-induced damage.