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1.
Nat Rev Endocrinol ; 16(9): 506-518, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32587391

RESUMO

Diabetes mellitus, which affects more than 463 million people globally, is caused by the autoimmune ablation or functional loss of insulin-producing ß-cells, and prevalence is projected to continue rising over the next decades. Generating ß-cells to mitigate the aberrant glucose homeostasis manifested in the disease has remained elusive. Substantial advances have been made in producing mature ß-cells from human pluripotent stem cells that respond appropriately to dynamic changes in glucose concentrations in vitro and rapidly function in vivo following transplantation in mice. Other potential avenues to produce functional ß-cells include: transdifferentiation of closely related cell types (for example, other pancreatic islet cells such as α-cells, or other cells derived from endoderm); the engineering of non-ß-cells that are capable of modulating blood sugar; and the construction of synthetic 'cells' or particles mimicking functional aspects of ß-cells. This Review focuses on the current status of generating ß-cells via these diverse routes, highlighting the unique advantages and challenges of each approach. Given the remarkable progress in this field, scalable bioengineering processes are also discussed for the realization of the therapeutic potential of derived ß-cells.


Assuntos
Diferenciação Celular , Diabetes Mellitus/terapia , Células Secretoras de Insulina/fisiologia , Células-Tronco Pluripotentes/fisiologia , Células-Tronco/fisiologia , Animais , Reatores Biológicos , Blastocisto/citologia , Células-Tronco Embrionárias/fisiologia , Humanos , Imunossupressores , Lactente , Recém-Nascido , Ilhotas Pancreáticas/fisiologia , Camundongos , Transplante de Células-Tronco
2.
Metabolism ; 104: 154137, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31904355

RESUMO

Type 1 diabetes mellitus (T1DM) is an autoimmune disease that targets the destruction of islet beta-cells resulting in insulin deficiency, hyperglycemia and death if untreated. Despite advances in medical devices and longer-acting insulin, there is still no robust therapy to substitute and protect beta-cells that are lost in T1DM. Attempts to refrain from the autoimmune attack have failed to achieve glycemic control in patients highlighting the necessity for a paradigm shift in T1DM treatment. Paradoxically, beta-cells are present in T1DM patients indicating a disturbed equilibrium between the immune attack and beta-cell regeneration reminiscent of unresolved wound healing that under normal circumstances progression towards an anti-inflammatory milieu promotes regeneration. Thus, the ultimate T1DM therapy should concomitantly restore immune self-tolerance and replenish the beta-cell mass similar to wound healing. Recently the agonistic activation of the nuclear receptor LRH-1/NR5A2 was shown to induce immune self-tolerance, increase beta-cell survival and promote regeneration through a mechanism of alpha-to-beta cell phenotypic switch. This trans-regeneration process appears to be facilitated by a pancreatic anti-inflammatory environment induced by LRH-1/NR5A2 activation. Herein, we review the literature on the role of LRH1/NR5A2 in immunity and islet physiology and propose that a cross-talk between these cellular compartments is mandatory to achieve therapeutic benefits.


Assuntos
Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 1/terapia , Inflamação/patologia , Ilhotas Pancreáticas/fisiologia , Animais , Humanos , Ilhotas Pancreáticas/patologia , Regeneração
3.
FASEB J ; 34(1): 1901-1911, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914605

RESUMO

Human pancreatic islets engrafted into immunodeficient mice serve as an important model for in vivo human diabetes studies. Following engraftment, islet function can be monitored in vivo by measuring circulating glucose and human insulin; however, it will be important to recover viable cells for more complex graft analyses. Moreover, RNA analyses of dissected grafts have not distinguished which hormone-specific cell types contribute to gene expression. We developed a method for recovering live cells suitable for fluorescence-activated cell sorting from human islets engrafted in mice. Although yields of recovered islet cells were relatively low, the ratios of bulk-sorted ß, α, and δ cells and their respective hormone-specific RNA-Seq transcriptomes are comparable pretransplant and posttransplant, suggesting that the cellular characteristics of islet grafts posttransplant closely mirror the original donor islets. Single-cell RNA-Seq transcriptome analysis confirms the presence of appropriate ß, α, and δ cell subsets. In addition, ex vivo perifusion of recovered human islet grafts demonstrated glucose-stimulated insulin secretion. Viable cells suitable for patch-clamp analysis were recovered from transplanted human embryonic stem cell-derived ß cells. Together, our functional and hormone-specific transcriptome analyses document the broad applicability of this system for longitudinal examination of human islet cells undergoing developmental/metabolic/pharmacogenetic manipulation in vivo and may facilitate the discovery of treatments for diabetes.


Assuntos
Células Endócrinas/fisiologia , Ilhotas Pancreáticas/fisiologia , Transcriptoma/fisiologia , Adulto , Animais , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Células Endócrinas/metabolismo , Feminino , Perfilação da Expressão Gênica/métodos , Sobrevivência de Enxerto/fisiologia , Humanos , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/fisiologia , Ilhotas Pancreáticas/metabolismo , Transplante das Ilhotas Pancreáticas/métodos , Masculino , Camundongos , Transplante Heterólogo/métodos , Adulto Jovem
4.
Metabolism ; 102: 153963, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31593706

RESUMO

BACKGROUND: Pregnancy represents a major metabolic challenge for the mother, and involves a compensatory response of the pancreatic beta-cell to maintain normoglycemia. However, although pancreatic alpha-cells play a key role in glucose homeostasis and seem to be involved in gestational diabetes, there is no information about their potential adaptations or changes during pregnancy. MATERIAL AND METHODS: Non-pregnant (controls) and pregnant C57BL/6 mice at gestational day 18.5 (G18.5) and their isolated pancreatic islets were used for in vivo and ex vivo studies, respectively. The effect of pregnancy hormones was tested in glucagon-secreting α-TC1.9 cells. Immunohistochemical analysis was performed in pancreatic slices. Glucagon gene expression was monitored by RT-qPCR. Glucagon secretion and plasma hormones were measured by ELISA. RESULTS: Pregnant mice on G18.5 exhibited alpha-cell hypertrophy as well as augmented alpha-cell area and mass. This alpha-cell mass expansion was mainly due to increased proliferation. No changes in alpha-cell apoptosis, ductal neogenesis, or alpha-to-beta transdifferentiation were found compared with controls. Pregnant mice on G18.5 exhibited hypoglucagonemia. Additionally, in vitro glucagon secretion at low glucose levels was decreased in isolated islets from pregnant animals. Glucagon content was also reduced. Experiments in α-TC1.9 cells indicated that, unlike estradiol and progesterone, placental lactogens and prolactin stimulated alpha-cell proliferation. Placental lactogens, prolactin and estradiol also inhibited glucagon release from α-TC1.9 cells at low glucose levels. CONCLUSIONS: The pancreatic alpha-cell in mice undergoes several morphofunctional changes during late pregnancy, which may contribute to proper glucose homeostasis. Gestational hormones are likely involved in these processes.


Assuntos
Adaptação Fisiológica/fisiologia , Idade Gestacional , Células Secretoras de Glucagon/citologia , Células Secretoras de Glucagon/fisiologia , Animais , Contagem de Células , Tamanho Celular , Células Cultivadas , Feminino , Glucagon/metabolismo , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Hormônios Placentários/fisiologia , Gravidez
5.
Int J Mol Sci ; 20(24)2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31817798

RESUMO

Gestational diabetes mellitus (GDM), a metabolic disease that develops with the increase in insulin resistance during late pregnancy, is currently one of the most common complications affecting pregnancy. The polygenic nature of GDM, together with the interplay between different genetic variants with nutritional and environmental factors has hindered the full understanding of the etiology of this disease. However, an important genetic overlap has been found with type 2 diabetes mellitus (T2DM) and, as in the case of T2DM, most of the identified loci are associated with ß-cell function. Early detection of GDM and adequate interventions to control the maternal glycemia are necessary to avoid the adverse outcomes for both the mother and the offspring. The in utero exposure to the diabetic milieu predispose these children for future diseases, among them T2DM, originating a vicious circle implicated in the increased prevalence of both GDM and T2DM. The involvement of inflammatory processes in the development of GDM highlights the importance of pancreatic ß-cell factors able to favor the adaptation processes required during gestation, concomitantly with the protection of the islets from an inflammatory milieu. In this regard, two members of the Pax family of transcription factors, PAX4 and PAX8, together with the chromatin remodeler factor HMG20A, have gained great relevance due to their involvement in ß-cell mass adaptation together with their anti-inflammatory properties. Mutations in these factors have been associated with GDM, highlighting these as novel candidates for genetic screening analysis in the identification of women at risk of developing GDM.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Gestacional/metabolismo , Diabetes Gestacional/fisiopatologia , Ilhotas Pancreáticas/fisiologia , Glicemia/metabolismo , Feminino , Proteínas de Grupo de Alta Mobilidade/metabolismo , Proteínas de Homeodomínio/metabolismo , Humanos , Fator de Transcrição PAX8/metabolismo , Fatores de Transcrição Box Pareados/metabolismo , Gravidez
6.
Biomed Microdevices ; 21(4): 91, 2019 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-31686215

RESUMO

Transplantation of pancreatic islets is becoming a promising therapy for people with type I diabetes. In this study, we present a compact fluidic system that enables assessment of islet functionality ex vivo for efficient islet transplantation. The fluidic system includes a micromesh sheet-embedded chip. Islets can be loaded easily on the micromesh sheet and observed clearly by microscopy. Islets on the mesh sheet mainly remained in place during perfusion and did not get damaged by hydraulic pressure because of high porosity of the micromesh sheet. The fluidic system was assembled with a sample fraction chip of polydimethylsiloxane. The chip includes a channel and columns, both having surfaces that were super-hydrophilized so that solutions could flow smoothly within the chip by gravity. Using mouse pancreatic islets, a dynamic glucose-stimulated insulin secretion test was performed to examine the performance of the fluidic system. The system successfully analyzed levels and patterns of insulin secretion upon exposure of the islets to low- and high-glucose solutions in turns, thus demonstrating its capacity to assess islet functions more easily and cost-effectively.


Assuntos
Ilhotas Pancreáticas/fisiologia , Dispositivos Lab-On-A-Chip , Animais , Dimetilpolisiloxanos , Desenho de Equipamento , Glucose/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Camundongos , Nylons
7.
Endocrinology ; 160(11): 2759-2772, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31504428

RESUMO

Thyroid hormones (THs) are crucial regulators of glucose metabolism and insulin sensitivity. Moreover, inactivating mutations in type 2 deiodinase (DIO2), the major TH-activating enzyme, have been associated with type 2 diabetes mellitus in both humans and mice. We studied the link between Dio2 deficiency and glucose homeostasis in fasted males of two different Dio2 knockout (KO) zebrafish lines. Young adult Dio2KO zebrafish (6 to 9 months) were hyperglycemic. Both insulin and glucagon expression were increased, whereas ß and α cell numbers in the main pancreatic islet were similar to those in wild-types. Insulin receptor expression in skeletal muscle was decreased at 6 months, accompanied by a strong downregulation of hexokinase and pyruvate kinase expression. Blood glucose levels in Dio2KO zebrafish, however, normalized around 1 year of age. Older mutants (18 to 24 months) were normoglycemic, and increased insulin and glucagon expression was accompanied by a prominent increase in pancreatic islet size and ß and α cell numbers. Older Dio2KO zebrafish also showed strongly decreased expression of glucagon receptors in the gastrointestinal system as well as decreased expression of glucose transporters GLUT2 and GLUT12, glucose-6-phosphatase, and glycogen synthase 2. This study shows that Dio2KO zebrafish suffer from transient hyperglycemia, which is counteracted with increasing age by a prominent hyperplasia of the endocrine pancreas together with decreases in hepatic glucagon sensitivity and intestinal glucose uptake. Further research on the mechanisms allowing compensation in older Dio2KO zebrafish may help to identify new therapeutic targets for (TH deficiency-related) hyperglycemia.


Assuntos
Glucose/metabolismo , Iodeto Peroxidase/deficiência , Envelhecimento/metabolismo , Animais , Animais Geneticamente Modificados , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Homeostase , Hiperglicemia/genética , Iodeto Peroxidase/genética , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/fisiologia , Masculino , Proglucagon/metabolismo , Proinsulina/metabolismo , Receptor de Insulina/metabolismo , Receptores de Glucagon/metabolismo , Peixe-Zebra
8.
Am J Physiol Endocrinol Metab ; 317(5): E794-E804, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31526288

RESUMO

Pancreatic islets adapt to the increase in insulin demand during pregnancy by upregulating ß-cell number, insulin synthesis, and secretion. These changes require prolactin receptor (PrlR) signaling, as mice with PrlR deletion are glucose intolerant with a lower ß-cell mass. Prolactin also prevents ß-cell apoptosis. Many genes participate in these adaptive changes in the islet, and Lrrc55 is one of the most upregulated genes with unknown function in islets. Because Lrrc55 expression increases in parallel to the increase in ß-cell number and insulin production during pregnancy, we hypothesize that Lrrc55 might regulate ß-cell proliferation/apoptosis (thus ß-cell number) and insulin synthesis. Here, we found that Lrrc55 expression was upregulated by >60-fold during pregnancy in a PrlR-dependent manner, and this increase was restricted only to the islets. Overexpression of Lrrc55 in ß-cells had minimal effect on ß-cell proliferation and glucose-stimulated insulin secretion but protected ß-cells from glucolipotoxicity-induced reduction in insulin gene expression. Moreover, Lrrc55 protects ß-cells from glucolipotoxicity-induced apoptosis, with upregulation of prosurvival signals and downregulation of proapoptotic signals of the endoplasmic reticulum (ER) stress pathway. Furthermore, Lrrc55 attenuated calcium depletion induced by glucolipotoxicity, which may contribute to its antiapoptotic effect. Hence our findings suggest that Lrrc55 is a novel prosurvival factor that is upregulated specifically in islets during pregnancy, and it prevents conversion of adaptive unfolded protein response to unresolved ER stress and apoptosis in ß-cells. Lrrc55 could be a potential therapeutic target in diabetes by reducing ER stress and promoting ß-cell survival.


Assuntos
Células Secretoras de Insulina/fisiologia , Ilhotas Pancreáticas/fisiologia , Proteínas de Membrana/fisiologia , Animais , Apoptose/genética , Apoptose/fisiologia , Cálcio/metabolismo , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , Diabetes Mellitus Experimental/genética , Feminino , Insulina/biossíntese , Insulina/genética , Secreção de Insulina/genética , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Transdução de Sinais/genética , Resposta a Proteínas não Dobradas/genética , Regulação para Cima
9.
J Diabetes Res ; 2019: 2813489, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31467926

RESUMO

While the autoimmune character of T1D (type 1 diabetes) is being challenged, it is currently recognized that inflammation plays a key role in its development. We hypothesized that glucotoxicity could contribute to ß-cell mass destruction through participation in islet inflammation. We evaluated the potential of empagliflozin (EMPA) and GABA (gamma-aminobutyric acid) to protect ß-cell mass against glucotoxicity and to increase ß-cell mass after diagnosis of T1D. Empagliflozin is a SGLT2 (sodium-dependent glucose cotransporter) inhibitor which thereby blocks glucose recapture by the kidney and promotes glucose excretion in urine. GABA is an inhibitory neurotransmitter, which stimulates α-to-ß cell transdifferentiation. In streptozotocin-treated mice, empagliflozin and/or GABA were delivered for a period of five days or three weeks. As compared to untreated T1D mice, EMPA-treated T1D mice had decreased FFA (free fatty acid) levels and improved glucose homeostasis. EMPA-treated T1D mice had higher islet density, with preserved architecture, compared to T1D mice, and EMPA-treated T1D mice also differed from T1D mice by the total absence of immune cell infiltration within islets. Islets from EMPA-treated mice were also less subjected to ER (endoplasmic reticulum) stress and inflammation, as shown by qPCR analysis. Glucose homeostasis parameters and islet area/pancreas area ratio improved, as compared to diabetic controls, when T1D mice were treated for three weeks with GABA and EMPA. T1D EMPA+GABA mice had higher glucagon levels than T1D mice, without modifications of glucagon area/islet area ratios. In conclusion, empagliflozin and GABA, used in monotherapy in streptozotocin-induced diabetic mice, have positive effects on ß-cell mass preservation or proliferation through an indirect effect on islet cell inflammation and ER stress. Further research is mandatory to evaluate whether empagliflozin and GABA may be a potential therapeutic target for the protection of ß-cell mass after new-onset T1D.


Assuntos
Compostos Benzidrílicos/farmacologia , Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Glucosídeos/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Ácido gama-Aminobutírico/farmacologia , Animais , Compostos Benzidrílicos/administração & dosagem , Glicemia/metabolismo , Contagem de Células , Proliferação de Células/efeitos dos fármacos , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patologia , Esquema de Medicação , Quimioterapia Combinada , Intervenção Médica Precoce , Teste de Tolerância a Glucose , Glucosídeos/administração & dosagem , Injeções Intraperitoneais , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/fisiologia , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/fisiologia , Masculino , Camundongos , Estreptozocina , Fatores de Tempo , Ácido gama-Aminobutírico/administração & dosagem
10.
J Diabetes Res ; 2019: 5451038, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31467927

RESUMO

Aims: Posttranslational modifications of histones and transcription factors regulate gene expression and are implicated in beta-cell failure and diabetes. We have recently shown that preserving H3K27 and H3K4 methylation using the lysine demethylase inhibitor GSK-J4 reduces cytokine-induced destruction of beta-cells and improves beta-cell function. Here, we investigate the therapeutic potential of GSK-J4 to prevent diabetes development and examine the importance of H3K4 methylation for islet function. Materials and Methods: We used two mouse models of diabetes to investigate the therapeutic potential of GSK-J4. To clarify the importance of H3K4 methylation, we characterized a mouse strain with knockout (KO) of the H3K4 demethylase KDM5B. Results: GSK-J4 administration failed to prevent the development of experimental diabetes induced by multiple low-dose streptozotocin or adoptive transfer of splenocytes from acutely diabetic NOD to NODscid mice. KDM5B-KO mice were growth retarded with altered body composition, had low IGF-1 levels, and exhibited reduced insulin secretion. Interestingly, despite secreting less insulin, KDM5B-KO mice were able to maintain normoglycemia following oral glucose tolerance test, likely via improved insulin sensitivity, as suggested by insulin tolerance testing and phosphorylation of proteins belonging to the insulin signaling pathway. When challenged with high-fat diet, KDM5B-deficient mice displayed similar weight gain and insulin sensitivity as wild-type mice. Conclusion: Our results show a novel role of KDM5B in metabolism, as KDM5B-KO mice display growth retardation and improved insulin sensitivity.


Assuntos
Metabolismo dos Carboidratos/genética , Proteínas de Ligação a DNA/fisiologia , Glucose/metabolismo , Células Secretoras de Insulina/fisiologia , Ilhotas Pancreáticas/fisiologia , Histona Desmetilases com o Domínio Jumonji/fisiologia , Animais , Proteínas de Ligação a DNA/genética , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Transtornos do Crescimento/genética , Transtornos do Crescimento/metabolismo , Homeostase/genética , Resistência à Insulina/genética , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Histona Desmetilases com o Domínio Jumonji/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Estreptozocina
11.
Endocrinology ; 160(8): 1907-1925, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31237608

RESUMO

Fetal exposure to gestational diabetes mellitus (GDM) and poor postnatal diet are strong risk factors for type 2 diabetes development later in life, but the mechanisms connecting GDM exposure to offspring metabolic health remains unclear. In this study, we aimed to determine how GDM interacts with the postnatal diet to affect islet function in the offspring as well as characterize the gene expression changes in the islets. GDM was induced in female rats using a high-fat, high-sucrose (HFS) diet, and litters from lean or GDM dams were weaned onto a low-fat (LF) or HFS diet. Compared with the lean control offspring, GDM exposure reduced glucose-stimulated insulin secretion in islets isolated from 15-week-old offspring, which was additively worsened when GDM exposure was combined with postnatal HFS diet consumption. In the HFS diet-fed offspring of lean dams, islet size and number increased, an adaptation that was not observed in the HFS diet-fed offspring of GDM dams. Islet gene expression in the offspring of GDM dams was altered in such categories as inflammation (e.g., Il1b, Ccl2), mitochondrial function/oxidative stress resistance (e.g., Atp5f1, Sod2), and ribosomal proteins (e.g., Rps6, Rps14). These results demonstrate that GDM exposure induced marked changes in gene expression in the male young adult rat offspring that cumulatively interact to worsen islet function, whole-body glucose homeostasis, and adaptations to HFS diets.


Assuntos
Diabetes Gestacional/fisiopatologia , Ilhotas Pancreáticas/fisiologia , Animais , Peso Corporal , Dieta Hiperlipídica , Feminino , Expressão Gênica , Glucose/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Gravidez , Ratos , Ratos Sprague-Dawley , Sacarose/administração & dosagem
12.
Phys Biol ; 16(5): 051001, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31212272

RESUMO

Controlling the excess and shortage of energy is a fundamental task for living organisms. Diabetes is a representative metabolic disease caused by the malfunction of energy homeostasis. The islets of Langerhans in the pancreas release long-range messengers, hormones, into the blood to regulate the homeostasis of the primary energy fuel, glucose. The hormone and glucose levels in the blood show rhythmic oscillations with a characteristic period of 5-10 min, and the functional roles of the oscillations are not clear. Each islet has [Formula: see text] and [Formula: see text] cells that secrete glucagon and insulin, respectively. These two counter-regulatory hormones appear sufficient to increase and decrease glucose levels. However, pancreatic islets have a third cell type, [Formula: see text] cells, which secrete somatostatin. The three cell populations have a unique spatial organization in islets, and they interact to perturb their hormone secretions. The mini-organs of islets are scattered throughout the exocrine pancreas. Considering that the human pancreas contains approximately a million islets, the coordination of hormone secretion from the multiple sources of islets and cells within the islets should have a significant effect on human physiology. In this review, we introduce the hierarchical organization of tripartite cell networks, and recent biophysical modeling to systematically understand the oscillations and interactions of [Formula: see text], [Formula: see text], and [Formula: see text] cells. Furthermore, we discuss the functional roles and clinical implications of hormonal oscillations and their phase coordination for the diagnosis of type II diabetes.


Assuntos
Glucose/fisiologia , Homeostase , Ilhotas Pancreáticas/fisiologia , Animais , Glucagon/metabolismo , Humanos , Insulina/metabolismo
13.
Islets ; 11(2): 21-32, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31050588

RESUMO

In vivo levels of insulin are oscillatory with a period of ~5-10 minutes, indicating that the islets of Langerhans within the pancreas are synchronized. While the synchronizing factors are still under investigation, one result of this behavior is expected to be coordinated and oscillatory intracellular factors, such as intracellular Ca2+ levels, throughout the islet population. In other cell types, oscillatory intracellular signals, like intracellular Ca2+, have been shown to affect specific gene expression. To test how the gene expression landscape may differ between a synchronized islet population with its reproducible intracellular oscillations and an unsynchronized islet population with heterogeneous oscillations, gene set enrichment analysis (GSEA) was used to compare an islet population that had been synchronized using a glucose wave with a 5-min period, and an unsynchronized islet population. In the population exposed to the glucose wave, 58/62 islets showed synchronization as evidenced by coordinated intracellular Ca2+ oscillations with an average oscillation period of 5.1 min, while in the unsynchronized population 29/62 islets showed slow oscillations with an average period of 5.2 min. The synchronized islets also had a significantly smaller drift of their oscillation period during the experiment as compared to the unsynchronized population. GSEA indicated that the synchronized population had reduced expression of gene sets related to protein translation, protein turnover, energy expenditure, and insulin synthesis, while those that were related to maintenance of cell morphology were increased.


Assuntos
Ciclos de Atividade/genética , Sinalização do Cálcio/genética , Cálcio/metabolismo , Ilhotas Pancreáticas/fisiologia , Transcriptoma , Animais , Células Cultivadas , Metabolismo Energético/genética , Glucose/farmacologia , Insulina/biossíntese , Masculino , Camundongos , Cultura Primária de Células , Biossíntese de Proteínas/genética , Fatores de Tempo , Transcriptoma/efeitos dos fármacos
15.
Biomed Pharmacother ; 112: 108674, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30784942

RESUMO

BACKGROUND AND PURPOSE: Islet transplantation is considered as a promising approach in the treatment of diabetes type 1. In this regard, optimal culture of the pancreatic islets is promising in the success of transplantation. In the present study, the effect of olesoxime, as an antiapoptotic substance, was evaluated on human islet culture. EXPERIMENTAL APPROACH: The pancreatic islets were isolated by mechanical and enzymatic techniques. After overnight recovery, the islets were treated by different concentrations of olesoxime for 24 and 72 h. Then, they were examined in terms of viability, apoptosis, genes and proteins expression including BAX, BCL2, active caspase-3, and insulin. Moreover, the islets function was evaluated through the glucose-induced insulin and C-peptide secretion assay. KEY RESULTS: Our findings showed that the islets increased in apoptosis and the decreased in viability after 72 h; also, insulin and C-peptide secretion reduced. However, in the presence of olesoxime, BAX/BCL2 ratio and the activation of caspase-3 were decreased. Therefore, olesoxime could improve the viability of the islets with the decrease of apoptosis. CONCLUSION: The application of olesoxime can reduce the stressful condition for the islets in vitro and subsequently improve their viability and functionality.


Assuntos
Apoptose/efeitos dos fármacos , Colestenonas/farmacologia , Citoproteção/efeitos dos fármacos , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Adulto , Apoptose/fisiologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Citoproteção/fisiologia , Feminino , Humanos , Ilhotas Pancreáticas/fisiologia , Masculino , Pessoa de Meia-Idade , Transdução de Sinais/fisiologia
16.
Surg Today ; 49(6): 536-545, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30730004

RESUMO

PURPOSE: Epigallocatechin 3-gallate (EGCG), a green tea polyphenol, has been shown to have anti-oxidant and anti-inflammatory effects in vitro and in vivo. The aim of this study was to investigate the effects and mechanism of EGCG on isolated pancreatic islets as pre-conditioning for pancreatic islet transplantation. METHODS: The pancreatic islets were divided into two groups: an islet culture medium group (control) and an islet culture medium with EGCG (100 µM) group. We investigated the islet viability, Nrf2 expression, reactive oxygen species (ROS) production, and heme oxygenase-1 (HO-1) mRNA. Five hundred islet equivalents after 12 h of culture for the EGCG 100 µM and control group were transplanted under the kidney capsule of streptozotocin-induced diabetic ICR mice. RESULTS: The cell viability and insulin secretion ability in the EGCG group were preserved, and the nuclear translocation of Nrf2 was increased in the EGCG group (p < 0.01). While the HO-1 mRNA levels were also higher in the EGCG group than in the control group (p < 0.05), the ROS production was lower (p < 0.01). An in vivo functional assessment showed that the blood glucose level had decreased in the EGCG group after transplantation (p < 0.01). CONCLUSION: EGCG protects the viability and function of islets by suppressing ROS production via the Nrf2 pathway.


Assuntos
Catequina/análogos & derivados , Expressão Gênica/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/fisiologia , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , RNA Mensageiro/metabolismo , Animais , Glicemia , Catequina/farmacologia , Sobrevivência Celular , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Técnicas In Vitro , Secreção de Insulina/efeitos dos fármacos , Ilhotas Pancreáticas/citologia , Transplante das Ilhotas Pancreáticas , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , RNA Mensageiro/genética , Espécies Reativas de Oxigênio/metabolismo , Técnicas de Cultura de Tecidos , Condicionamento Pré-Transplante
17.
Diabetes Obes Metab ; 21(5): 1209-1222, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30690849

RESUMO

AIMS: The potential effect of regenerating (Reg) proteins in the treatment of diabetes has been indicated in the past decade, but the clinical use of Reg proteins requires more advances in translational medicine. In the present study, we produced recombinant regenerating protein 2 (rReg2), to prove its protective effect against streptozocin (STZ)-induced diabetes in BALB/c mice. MATERIALS AND METHODS: rReg2 was administrated in STZ-induced diabetic mice. Blood glucose, body weight, serum insulin and islet ß-cell loss were determined. However, Reg2 has also been reported to serve as an autoantigen that induces autoimmune attacks on islets and aggravates diabetic development in non-obese diabetic mice. To address this contradiction, complete Freund's adjuvant was injected to generate a model that was hypersensitive to Reg2. In this model, islet CD8 T-cell infiltration, serum Reg2 antibody and interleukin (IL)-4 and IL-10, and splenic CD4+/interferon (IFN)-γ+ T cells were determined. RESULTS: Direct rReg2 pretreatment preserved islet ß-cell mass against STZ and improved glycaemia, body weight and serum insulin content. The protection against cell death was further confirmed in cultured mouse islets and MIN6 cells. On the other hand, significant elevations of serum Reg2 antibody and splenic CD4+/IFN-γ+ T cells, and decreases in serum IL-4 and IL-10 were detected in rReg2-vaccinated mice, which may contribute to the accelerated diabetes. Interestingly, these mice, upon further rReg2 treatment, exhibited alleviated diabetic conditions with less islet CD8+ T-cell infiltration. CONCLUSION: rReg2 treatment ameliorated STZ-induced diabetes in normal BALB/c mice. By contrast, rReg2 vaccination exacerbated, but further rReg2 treatment alleviated, the severity of STZ-induced diabetes. Thus, the protective effect of rReg2 is predominant over the autoantigenic ß-cell destruction, supporting the potential of rReg2 in the clinical treatment of diabetes.


Assuntos
Autoantígenos/sangue , Citoproteção/efeitos dos fármacos , Diabetes Mellitus Experimental/tratamento farmacológico , Células Secretoras de Insulina/efeitos dos fármacos , Ilhotas Pancreáticas/efeitos dos fármacos , Proteínas Associadas a Pancreatite/farmacologia , Animais , Apoptose/efeitos dos fármacos , Células Cultivadas , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/patologia , Células Secretoras de Insulina/patologia , Células Secretoras de Insulina/fisiologia , Ilhotas Pancreáticas/patologia , Ilhotas Pancreáticas/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Associadas a Pancreatite/química , Fragmentos de Peptídeos/farmacologia , Substâncias Protetoras/farmacologia , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologia , Estreptozocina
18.
Diabetes Obes Metab ; 21(2): 330-339, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30203438

RESUMO

AIMS: To evaluate the role of free fatty acid receptor 2 (FFAR2)/G-protein coupled receptor 43 in mediating the effects of the short chain fatty acids (SCFAs) sodium acetate (SA) and sodium propionate (SP) on islet function in vitro, and to identify the intracellular signalling pathways used in SCFA-induced potentiation of glucose-induced insulin secretion. MATERIALS AND METHODS: Islets of Langerhans were isolated from wild-type and FFAR2-/- mice and from human donors without diabetes. The effects of SA and SP on dynamic insulin secretion from perifused islets were quantified by radioimmunoassay, signalling downstream of SCFAs was profiled by single-cell calcium microfluorimetry, and measurement of cAMP was performed using a fluorescence assay. Islet apoptosis was induced by exposure to cytokines or sodium palmitate, and the effects of SA and SP in regulating islet apoptosis were assessed by quantification of caspase 3/7 activities. RESULTS: Deletion of FFAR2 did not affect islet morphology or insulin content. SA and SP reversibly potentiated insulin secretion from mouse islets in a FFAR2-dependent manner. SCFA-induced potentiation of insulin secretion was coupled to Gq activation of phospholipase C and protein kinase C, with no evidence of Gi-mediated signalling. SA and SP protected human and mouse islets from apoptosis, and these pro-survival properties were dependent on islet expression of FFAR2. CONCLUSION: Our results indicate that FFAR2 directly mediates both the stimulatory effects of SA and SP on insulin secretion and their protection against islet apoptosis. We have also shown that SCFA coupling in islets occurs via Gq-coupled intracellular signalling.


Assuntos
Apoptose/efeitos dos fármacos , Ácidos Graxos Voláteis/farmacologia , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Ilhotas Pancreáticas/efeitos dos fármacos , Receptores Acoplados a Proteínas-G/fisiologia , Adulto , Animais , Apoptose/genética , Células Cultivadas , Ácidos Graxos não Esterificados/farmacologia , Feminino , Humanos , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/patologia , Ilhotas Pancreáticas/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Propionatos/farmacologia , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/fisiologia , Receptores Acoplados a Proteínas-G/genética , Acetato de Sódio/farmacologia
19.
Trends Endocrinol Metab ; 30(1): 4-11, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30502039

RESUMO

Adult pancreatic regeneration is one of the most contentious topics in modern biology. The long-held view that the islets of Langerhans can be replenished throughout adult life through the reactivation of ductal progenitor cells has been replaced over the past decade by the now prevailing notion that regeneration does not involve progenitors and occurs only through the duplication of pre-existing mature cells. Here we dissect the limitations of lineage tracing (LT) to draw categorical conclusions about pancreatic regeneration, especially in view of emerging evidence that traditional lineages are less homogeneous and cell fates more dynamic than previously thought. This new evidence further suggests that the two competing hypotheses about regeneration are not mutually exclusive.


Assuntos
Linhagem da Célula/fisiologia , Ilhotas Pancreáticas/fisiologia , Pâncreas/fisiologia , Regeneração/fisiologia , Células-Tronco/fisiologia , Animais , Humanos
20.
J Cell Physiol ; 234(7): 11500-11510, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30515793

RESUMO

Diabetes and cardiometabolic risk factors including hypertension and dyslipidemia are the major threats to human health in the 21st century. Apoptosis in pancreatic tissue is one of the major causes of diabetes type 1 progression. The aim of this study was to investigate the effects of C-peptide or l-arginine on some cardiometabolic risk factors, pancreatic morphology, function and apoptosis, and the mechanisms of their actions. Forty adult male albino rats were divided into four equal groups: 1-control nondiabetic, 2-diabetic (no treatment), 3-diabetic + C-peptide, and 4-diabetic + l-arginine. Diabetes was induced by a single intraperitoneal injection of high dose streptozotocin. At the end of the experiment, sera glucose, insulin levels, total antioxidant capacity (TAC), malondialdehyde (MDA), nitric oxide (NO), and pancreatic MDA, TAC, and B-cell lymphoma 2 were measured. The morphology and proliferating activity of the pancreas were examined by hematoxylin and eosin histological stain, proliferative cell nuclear antigen (PCNA), and insulin antibodies. Our results showed that induction of diabetes caused hyperglycemia, dyslipidemia, and oxidative stress. However, administration of C-peptide or l-arginine significantly improved the pancreatic histopathology with a significant increase in the area % of insulin immunoreactivity, the number of PCNA immunopositive cells, the number of islets, and the diameter of islets compared with the diabetic group. C-peptide treatment of the diabetic rats completely corrected these errors, while l-arginine partially antagonized the above diabetic complications. So the administration of C-peptide as an adjuvant therapy in type 1 diabetes can significantly decrease apoptosis of pancreas and subsequent progression of diabetes complication.


Assuntos
Arginina/farmacologia , Peptídeo C/farmacologia , Proliferação de Células/efeitos dos fármacos , Diabetes Mellitus Experimental , Células Secretoras de Insulina/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Glicemia , Regulação da Expressão Gênica/efeitos dos fármacos , Insulina/sangue , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/fisiologia , Masculino , Antígeno Nuclear de Célula em Proliferação/genética , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ratos , Ratos Sprague-Dawley
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