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1.
PLoS One ; 15(12): e0241349, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33347462

RESUMO

Beta cell apoptosis induced by proinflammatory cytokines is one of the hallmarks of diabetes. Small molecules which can inhibit the cytokine-induced apoptosis could lead to new drug candidates that can be used in combination with existing therapeutic interventions against diabetes. The current study evaluated several effects of bergenin, an isocoumarin derivative, in beta cells in the presence of cytokines. These included (i) increase in beta cell viability (by measuring cellular ATP levels) (ii) suppression of beta cell apoptosis (by measuring caspase activity), (iii) improvement in beta cell function (by measuring glucose-stimulated insulin secretion), and (iv) improvement of beta cells mitochondrial physiological functions. The experiments were carried out using rat beta INS-1E cell line in the presence or absence of bergenin and a cocktail of proinflammatory cytokines (interleukin-1beta, tumor necrosis factor-alpha, and interferon- gamma) for 48 hr. Bergenin significantly inhibited beta cell apoptosis, as inferred from the reduction in the caspase-3 activity (IC50 = 7.29 ± 2.45 µM), and concurrently increased cellular ATP Levels (EC50 = 1.97 ± 0.47 µM). Bergenin also significantly enhanced insulin secretion (EC50 = 6.73 ± 2.15 µM) in INS-1E cells, presumably because of the decreased nitric oxide production (IC50 = 6.82 ± 2.83 µM). Bergenin restored mitochondrial membrane potential (EC50 = 2.27 ± 0.83 µM), decreased ROS production (IC50 = 14.63 ± 3.18 µM), and improved mitochondrial dehydrogenase activity (EC50 = 1.39 ± 0.62 µM). This study shows for the first time that bergenin protected beta cells from cytokine-induced apoptosis and restored insulin secretory function by virtue of its anti-inflammatory, antioxidant and anti-apoptotic properties. To sum up, the above mentioned data highlight bergenin as a promising anti-apoptotic agent in the context of diabetes.


Assuntos
Benzopiranos/farmacologia , Células Secretoras de Insulina/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citocinas/farmacologia , Glucose/farmacologia , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/fisiologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Óxido Nítrico/biossíntese , Ratos , Espécies Reativas de Oxigênio/metabolismo
2.
Nat Metab ; 2(12): 1443-1458, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33257854

RESUMO

The in vitro differentiation of insulin-producing beta-like cells can model aspects of human pancreatic development. Here, we generate 95,308 single-cell transcriptomes and reconstruct a lineage tree of the entire differentiation process from human embryonic stem cells to beta-like cells to study temporally regulated genes during differentiation. We identify so-called 'switch genes' at the branch point of endocrine/non-endocrine cell fate choice, revealing insights into the mechanisms of differentiation-promoting reagents, such as NOTCH and ROCKII inhibitors, and providing improved differentiation protocols. Over 20% of all detectable genes are activated multiple times during differentiation, even though their enhancer activation is usually unimodal, indicating extensive gene reuse driven by different enhancers. We also identify a stage-specific enhancer at the TCF7L2 locus for diabetes, uncovered by genome-wide association studies, that drives a transient wave of gene expression in pancreatic progenitors. Finally, we develop a web app to visualize gene expression on the lineage tree, providing a comprehensive single-cell data resource for researchers studying islet biology and diabetes.


Assuntos
Diferenciação Celular/fisiologia , Linhagem da Célula/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Células Secretoras de Insulina/fisiologia , Diferenciação Celular/genética , Linhagem da Célula/genética , Diabetes Mellitus/genética , Células-Tronco Embrionárias , Regulação da Expressão Gênica no Desenvolvimento/genética , Técnicas de Silenciamento de Genes , Genes de Troca/genética , Glucose/farmacologia , Humanos , Secreção de Insulina/efeitos dos fármacos , Proteína 2 Semelhante ao Fator 7 de Transcrição/genética , Fatores de Transcrição HES-1/biossíntese , Fatores de Transcrição HES-1/genética
3.
Nat Commun ; 11(1): 5982, 2020 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-33239617

RESUMO

Expanding the mass of pancreatic insulin-producing beta cells through re-activation of beta cell replication has been proposed as a therapy to prevent or delay the appearance of diabetes. Pancreatic beta cells exhibit an age-dependent decrease in their proliferative activity, partly related to changes in the systemic environment. Here we report the identification of CCN4/Wisp1 as a circulating factor more abundant in pre-weaning than in adult mice. We show that Wisp1 promotes endogenous and transplanted adult beta cell proliferation in vivo. We validate these findings using isolated mouse and human islets and find that the beta cell trophic effect of Wisp1 is dependent on Akt signaling. In summary, our study reveals the role of Wisp1 as an inducer of beta cell replication, supporting the idea that the use of young blood factors may be a useful strategy to expand adult beta cell mass.


Assuntos
Envelhecimento/fisiologia , Proteínas de Sinalização Intercelular CCN/metabolismo , Células Secretoras de Insulina/fisiologia , Transplante das Ilhotas Pancreáticas/métodos , Proteínas Proto-Oncogênicas/metabolismo , Envelhecimento/sangue , Animais , Proteínas de Sinalização Intercelular CCN/sangue , Proteínas de Sinalização Intercelular CCN/genética , Proliferação de Células , Células Cultivadas , Meios de Cultura/metabolismo , Diabetes Mellitus/terapia , Feminino , Humanos , Células Secretoras de Insulina/transplante , Masculino , Camundongos , Camundongos Knockout , Cultura Primária de Células/métodos , Proteínas Proto-Oncogênicas/sangue , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transdução de Sinais/fisiologia , Desmame
4.
Nat Commun ; 11(1): 5037, 2020 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-33028844

RESUMO

Pancreatic islets play an essential role in regulating blood glucose level. Although the molecular pathways underlying islet cell differentiation are beginning to be resolved, the cellular basis of islet morphogenesis and fate allocation remain unclear. By combining unbiased and targeted lineage tracing, we address the events leading to islet formation in the mouse. From the statistical analysis of clones induced at multiple embryonic timepoints, here we show that, during the secondary transition, islet formation involves the aggregation of multiple equipotent endocrine progenitors that transition from a phase of stochastic amplification by cell division into a phase of sublineage restriction and limited islet fission. Together, these results explain quantitatively the heterogeneous size distribution and degree of polyclonality of maturing islets, as well as dispersion of progenitors within and between islets. Further, our results show that, during the secondary transition, α- and ß-cells are generated in a contemporary manner. Together, these findings provide insight into the cellular basis of islet development.


Assuntos
Diferenciação Celular , Células Secretoras de Glucagon/fisiologia , Células Secretoras de Insulina/fisiologia , Pâncreas/embriologia , Animais , Linhagem da Célula/fisiologia , Simulação por Computador , Embrião de Mamíferos , Desenvolvimento Embrionário , Feminino , Genes Reporter/genética , Imageamento Tridimensional , Proteínas Luminescentes/genética , Masculino , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Modelos Animais , Modelos Biológicos , Organogênese , Pâncreas/diagnóstico por imagem , Células-Tronco/fisiologia
5.
Intern Med ; 59(18): 2229-2235, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32938850

RESUMO

Objective The measurement of C-peptide immunoreactivity (CPR) is essential for evaluating the pancreatic ß-cell function and selecting appropriate therapeutic agents in patients with diabetes mellitus. The meal tolerance test (MTT) is simple to administer physiological insulin-stimulating test. Previous studies have reported that several CPR-related indices are useful markers for predicting insulin requirement in type 2 diabetes. In the present study, we investigated the serum CPR response during the MTT in hospitalized patients with type 2 diabetes mellitus in order to clarify the clinical utility of the MTT. Methods We performed the MTT using a test meal with timed measurements of the serum CPR level based on the oral glucose tolerance test over 180 minutes and tested the correlation of various CPR-related indices and clinical factors in patients with type 2 diabetes mellitus. Patients The subjects were patients with type 2 diabetes mellitus who had been admitted to our hospital for diabetes management and education. The final study population consisted of 68 patients. Results The fasting CPR level was correlated with the 24-hour urinary CPR excretion and body mass index. The serum CPR level at 120 minutes in the MTT was strongly correlated with the area under the curve of CPR during the MTT. The patients who needed insulin therapy at 6 months after hospitalization showed a significant lower incremental CPR value from 0 to 120 minutes in the MTT than those who did not need insulin therapy. Conclusion The plasma C-peptide levels at 0 and 120 minutes in the MTT provide essential information for the clinical management of patients with type 2 diabetes mellitus.


Assuntos
Peptídeo C/sangue , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Técnicas de Diagnóstico Endócrino , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Adulto , Biomarcadores/sangue , Glicemia/metabolismo , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Teste de Tolerância a Glucose , Humanos , Insulina/sangue , Células Secretoras de Insulina/fisiologia , Masculino , Refeições , Carne , Pessoa de Meia-Idade , Período Pós-Prandial
6.
Am J Chin Med ; 48(6): 1435-1454, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32907363

RESUMO

Endoplasmic reticulum stress (ER stress) plays a main role in pancreatic [Formula: see text]-cell dysfunction and death because of intracellular Ca[Formula: see text] turbulence and inflammation activation. Although several drugs are targeting pancreatic [Formula: see text]-cell to improve [Formula: see text]-cell function, there still lacks agents to alleviate [Formula: see text]-cell ER stress conditions. Therefore we used thapsigargin (THAP) or high glucose (HG) to induce ER stress in [Formula: see text]-cell and aimed to screen natural molecules against ER stress-induced [Formula: see text]-cell dysfunction. Through screening the Traditional Chinese drug library ([Formula: see text] molecules), luteolin was finally discovered to improve [Formula: see text]-cell function. Cellular viability results indicated luteolin reduced the THAP or HG-induced [Formula: see text]-cell death and apoptosis through MTT and flow cytometry assay. Moreover, luteolin improved [Formula: see text]-cell insulin secretion ability under ER stress conditions. Also ER stress-induced intracellular Ca[Formula: see text] turbulence and inflammation activation were inhibited by luteolin treatment. Mechanically, luteolin inhibited HNF4[Formula: see text] signaling, which was induced by ER stress. Moreover, luteolin reduced the transcriptional level of HNF4[Formula: see text] downstream gene, such as Asnk4b and HNF1[Formula: see text]. Conversely HNF4[Formula: see text] knockdown abolished the effect of luteolin on [Formula: see text]-cell using siRNA. These results suggested the protective effect of luteolin on [Formula: see text]-cell was through HNF4[Formula: see text]/Asnk4b pathway. In conclusion, our study discovered that luteolin improved [Formula: see text]-cell function and disclosed the underlying mechanism of luteolin on [Formula: see text]-cell, suggesting luteolin is a promising agent against pancreatic dysfunction.


Assuntos
Sobrevivência Celular/efeitos dos fármacos , Medicamentos de Ervas Chinesas/química , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Fator 4 Nuclear de Hepatócito/genética , Fator 4 Nuclear de Hepatócito/metabolismo , Células Secretoras de Insulina/patologia , Células Secretoras de Insulina/fisiologia , Luteolina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Tapsigargina/efeitos adversos , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Morte Celular/efeitos dos fármacos , Células Cultivadas , Avaliação Pré-Clínica de Medicamentos , Estresse do Retículo Endoplasmático/fisiologia , Glucose/efeitos adversos , Células Secretoras de Insulina/metabolismo , Luteolina/isolamento & purificação
7.
Sci Rep ; 10(1): 15413, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32963286

RESUMO

Pancreatic ß-cells become irreversibly damaged by long-term exposure to excessive glucose concentrations and lose their ability to carry out glucose stimulated insulin secretion (GSIS) upon damage. The ß-cells are not able to control glucose uptake and they are therefore left vulnerable for endogenous toxicity from metabolites produced in excess amounts upon increased glucose availability. In order to handle excess fuel, the ß-cells possess specific metabolic pathways, but little is known about these pathways. We present a study of ß-cell metabolism under increased fuel pressure using a stable isotope resolved NMR approach to investigate early metabolic events leading up to ß-cell dysfunction. The approach is based on a recently described combination of 13C metabolomics combined with signal enhanced NMR via dissolution dynamic nuclear polarization (dDNP). Glucose-responsive INS-1 ß-cells were incubated with increasing concentrations of [U-13C] glucose under conditions where GSIS was not affected (2-8 h). We find that pyruvate and DHAP were the metabolites that responded most strongly to increasing fuel pressure. The two major divergence pathways for fuel excess, the glycerolipid/fatty acid metabolism and the polyol pathway, were found not only to operate at unchanged rate but also with similar quantity.


Assuntos
Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/fisiologia , Animais , Linhagem Celular , Ácidos Graxos/metabolismo , Glucose/metabolismo , Insulina/metabolismo , Secreção de Insulina/fisiologia , Metabolismo dos Lipídeos/fisiologia , Redes e Vias Metabólicas/fisiologia , Metabolômica/métodos , Pressão , Ácido Pirúvico/metabolismo , Ratos , Transdução de Sinais/fisiologia
8.
Sci Rep ; 10(1): 13469, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32778664

RESUMO

G protein-coupled receptors are seven transmembrane signaling molecules that are involved in a wide variety of physiological processes. They constitute a large protein family of receptors with almost 300 members detected in human pancreatic islet preparations. However, the functional role of these receptors in pancreatic islets is unknown in most cases. We generated a new stable human beta cell line from neonatal pancreas. This cell line, named ECN90 expresses both subunits (GABBR1 and GABBR2) of the metabotropic GABAB receptor compared to human islet. In ECN90 cells, baclofen, a specific GABAB receptor agonist, inhibits cAMP signaling causing decreased expression of beta cell-specific genes such as MAFA and PCSK1, and reduced insulin secretion. We next demonstrated that in primary human islets, GABBR2 mRNA expression is strongly induced under cAMP signaling, while GABBR1 mRNA is constitutively expressed. We also found that induction and activation of the GABAB receptor in human islets modulates insulin secretion.


Assuntos
Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Receptores de GABA-B/genética , Baclofeno/farmacologia , Linhagem Celular , Agonistas dos Receptores de GABA-B/farmacologia , Humanos , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/fisiologia , Ilhotas Pancreáticas/fisiologia , Pâncreas/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Receptores de GABA-B/metabolismo , Transdução de Sinais , Ácido gama-Aminobutírico/metabolismo
10.
Curr Opin Endocrinol Diabetes Obes ; 27(4): 215-224, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32618633

RESUMO

PURPOSE OF REVIEW: Emerging data have suggested that ß-cell dysfunction may exacerbate the development and progression of type 1 diabetes (T1D). In this review, we highlight clinical and preclinical studies suggesting a role for ß-cell dysfunction during the evolution of T1D and suggest agents that may promote ß-cell health in T1D. RECENT FINDINGS: Metabolic abnormalities exist years before development of hyperglycemia and exhibit a reproducible pattern reflecting progressive deterioration of ß-cell function and increases in ß-cell stress and death. Preclinical studies indicate that T1D may be prevented by modification of pathways impacting intrinsic ß-cell stress and antigen presentation. Recent findings suggest that differences in metabolic phenotypes and ß-cell stress may reflect differing endotypes of T1D. Multiple pathways representing potential drug targets have been identified, but most remain to be tested in human populations with preclinical disease. SUMMARY: This cumulative body of work shows clear evidence that ß-cell stress, dysfunction, and death are harbingers of impending T1D and likely contribute to progression of disease and insulin deficiency. Treatment with agents targeting ß-cell health could augment interventions with immunomodulatory therapies but will need to be tested in intervention studies with endpoints carefully designed to capture changes in ß-cell function and health.


Assuntos
Diabetes Mellitus Tipo 1/etiologia , Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 1/fisiopatologia , Células Secretoras de Insulina/fisiologia , Diabetes Mellitus Tipo 1/metabolismo , Progressão da Doença , Humanos , Hiperglicemia/sangue , Hiperglicemia/complicações , Hiperglicemia/patologia , Hiperglicemia/fisiopatologia , Insulina/deficiência , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia
11.
Am J Physiol Endocrinol Metab ; 319(2): E410-E426, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32663101

RESUMO

Diabetes is a chronic, progressive disease that calls for longitudinal data and analysis. We introduce a longitudinal mathematical model that is capable of representing the metabolic state of an individual at any point in time during their progression from normal glucose tolerance to type 2 diabetes (T2D) over a period of years. As an application of the model, we account for the diversity of pathways typically followed, focusing on two extreme alternatives, one that goes through impaired fasting glucose (IFG) first and one that goes through impaired glucose tolerance (IGT) first. These two pathways are widely recognized to stem from distinct metabolic abnormalities in hepatic glucose production and peripheral glucose uptake, respectively. We confirm this but go beyond to show that IFG and IGT lie on a continuum ranging from high hepatic insulin resistance and low peripheral insulin resistance to low hepatic resistance and high peripheral resistance. We show that IFG generally incurs IGT and IGT generally incurs IFG on the way to T2D, highlighting the difference between innate and acquired defects and the need to assess patients early to determine their underlying primary impairment and appropriately target therapy. We also consider other mechanisms, showing that IFG can result from impaired insulin secretion, that non-insulin-dependent glucose uptake can also mediate or interact with these pathways, and that impaired incretin signaling can accelerate T2D progression. We consider whether hyperinsulinemia can cause insulin resistance in addition to being a response to it and suggest that this is a minor effect.


Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Glicemia/análise , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/etiologia , Progressão da Doença , Jejum , Glucose/biossíntese , Intolerância à Glucose , Teste de Tolerância a Glucose , Humanos , Hiperinsulinismo/fisiopatologia , Incretinas/metabolismo , Insulina/metabolismo , Resistência à Insulina/fisiologia , Secreção de Insulina/fisiologia , Células Secretoras de Insulina/fisiologia , Fígado/metabolismo , Modelos Teóricos , Transdução de Sinais/fisiologia
12.
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
13.
Am J Physiol Endocrinol Metab ; 319(2): E345-E353, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32543943

RESUMO

Type 1 and type 2 diabetes are both tightly associated with impaired glucose control. Although both pathologies stem from different mechanisms, a reduction in insulin action coincides with drastic metabolic dysfunction in skeletal muscle and metabolic inflexibility. However, the underlying explanation for this response remains poorly understood, particularly since it is difficult to distinguish the role of attenuated insulin action from the detrimental effects of reactive lipid accumulation, which impairs mitochondrial function and promotes reactive oxygen species (ROS) emission. We therefore utilized streptozotocin to examine the effects of acute insulin deprivation, in the absence of a high-lipid/nutrient excess environment, on the regulation of mitochondrial substrate sensitivity and ROS emission. The ablation of insulin resulted in reductions in absolute mitochondrial oxidative capacity and ADP-supported respiration and reduced the ability for malonyl-CoA to inhibit carnitine palmitoyltransferase I (CPT-I) and suppress fatty acid-supported respiration. These bioenergetic responses coincided with increased mitochondrial-derived H2O2 emission and lipid transporter content, independent of major mitochondrial substrate transporter proteins and enzymes involved in fatty acid oxidation. Together, these data suggest that attenuated/ablated insulin signaling does not affect mitochondrial ADP sensitivity, whereas the increased reliance on fatty acid oxidation in situations where insulin action is reduced may occur as a result of altered regulation of mitochondrial fatty acid transport through CPT-I.


Assuntos
Ácidos Graxos/fisiologia , Insulina/deficiência , Mitocôndrias Musculares/metabolismo , Difosfato de Adenosina/farmacologia , Animais , Transporte Biológico/fisiologia , Carnitina O-Palmitoiltransferase/metabolismo , Peróxido de Hidrogênio/metabolismo , Insulina/fisiologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/fisiologia , Masculino , Mitocôndrias Musculares/efeitos dos fármacos , Músculo Esquelético/ultraestrutura , Oxirredução , Consumo de Oxigênio , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Estreptozocina/farmacologia
14.
Am J Physiol Endocrinol Metab ; 319(2): E388-E400, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32543944

RESUMO

Replacement of islets/ß-cells that provide long-lasting glucose-sensing and insulin-releasing functions has the potential to restore extended glycemic control in individuals with type 1 diabetes. Unfortunately, persistent challenges preclude such therapies from widespread clinical use, including cumbersome administration via portal vein infusion, significant loss of functional islet mass upon administration, limited functional longevity, and requirement for systemic immunosuppression. Previously, fibril-forming type I collagen (oligomer) was shown to support subcutaneous injection and in situ encapsulation of syngeneic islets within diabetic mice, with rapid (<24 h) reversal of hyperglycemia and maintenance of euglycemia for beyond 90 days. Here, we further evaluated this macroencapsulation strategy, defining effects of islet source (allogeneic and xenogeneic) and dose (500 and 800 islets), injection microenvironment (subcutaneous and intraperitoneal), and macrocapsule format (injectable and preformed implantable) on islet functional longevity and recipient immune response. We found that xenogeneic rat islets functioned similarly to or better than allogeneic mouse islets, with only modest improvements in longevity noted with dosage. Additionally, subcutaneous injection led to more consistent encapsulation outcomes along with improved islet health and longevity, compared with intraperitoneal administration, whereas no significant differences were observed between subcutaneous injectable and preformed implantable formats. Collectively, these results document the benefits of incorporating natural collagen for islet/ß-cell replacement therapies.


Assuntos
Encapsulamento de Células/métodos , Colágeno , Diabetes Mellitus Tipo 1/terapia , Transplante das Ilhotas Pancreáticas/métodos , Aloenxertos , Animais , Glicemia/análise , Sobrevivência Celular , Colágeno/química , Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 1/sangue , Sobrevivência de Enxerto , Xenoenxertos , Injeções Intraperitoneais , Injeções Subcutâneas , Células Secretoras de Insulina/fisiologia , Células Secretoras de Insulina/transplante , Ilhotas Pancreáticas/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Sprague-Dawley
15.
Am J Physiol Endocrinol Metab ; 319(2): E338-E344, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32574111

RESUMO

Obesity is associated with dyslipidemia and subclinical inflammation that promotes metabolic disturbances including insulin resistance and pancreatic ß-cell dysfunction. The nuclear protein, transcriptional regulator 1 (NUPR1) responds to cellular stresses and features tissue protective properties. To characterize the role of NUPR1 in endocrine pancreatic islets during inflammatory stress, we generated transgenic mice with ß-cell-specific Nupr1 overexpression (ßNUPR1). Under normal conditions, ßNUPR1 mice did not differ from wild type (WT) littermates and display normal glucose homeostasis and ß-cell mass. For induction of inflammatory conditions, mice were treated with multiple low-dose streptozotocin (mld-STZ) and/or fed a high-fat diet (HFD). All treatments significantly worsened glycaemia in WT mice, while ßNUPR1 mice substantially preserved insulin secretion and glucose tolerance. HFD increased ß-cell mass in all animals, with ßNUPR1 mice tending to show higher values. The improved outcome of ßNUPR1 mice was accompanied by decreased NF-κB activation and lymphocyte infiltration in response to mld-STZ. In vitro, isolated ßNUPR1 islets preserved insulin secretion and content with insignificantly low apoptosis during culture stress and IL-1ß exposure. These findings suggest that NUPR1 plays a vital role in the protection of ß-cells from apoptosis, related degradation of insulin storages and subsequent secretion during inflammatory and obesity-related tissue stress.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Dieta Hiperlipídica/efeitos adversos , Inflamação/fisiopatologia , Secreção de Insulina/fisiologia , Células Secretoras de Insulina/fisiologia , Proteínas de Neoplasias/fisiologia , Estreptozocina/administração & dosagem , Animais , Apoptose/fisiologia , Glicemia/análise , Células Cultivadas , Proteínas de Ligação a DNA/genética , Feminino , Expressão Gênica , Homeostase , Inflamação/etiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas de Neoplasias/genética , Fatores Sexuais
16.
Postgrad Med ; 132(8): 676-686, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32543261

RESUMO

It is well known that type 2 diabetes mellitus (T2D) is a globally increasing health burden. Despite recent therapeutic advances and the availability of many different classes of antihyperglycemic therapy, a large proportion of people do not achieve glycemic control. A decline in pancreatic beta-cell function has been defined as a key contributing factor to progression of T2D. In fact, a significant proportion of beta-cell secretory capacity is thought to be lost well before the diagnosis of T2D is made. Several models have been proposed to explain the reduction in beta-cell function, including reduced beta-cell number, beta-cell exhaustion, and dedifferentiation or transdifferentiation into other cell types. However, there have been reports that suggest remission of T2D is possible, and it is believed that beta-cell dysfunction may be, in part, reversible. As such, the question of whether beta cells are committed to failure in people with T2D is complex. It is now widely accepted that early restoration of normoglycemia may protect beta-cell function. Key to the successful implementation of this approach in clinical practice is the appropriate assessment of individuals at risk of beta-cell failure, and the early implementation of appropriate treatment options. In this review, we discuss the progression of T2D in the context of beta-cell failure and describe how C-peptide testing can be used to assess beta-cell function in primary care practice. In conclusion, significant beta-cell dysfunction is likely in individuals with certain clinical characteristics of T2D, such as long duration of disease, high glycated hemoglobin (≥9%), and/or long-term use of therapies that continuously stimulate the beta cell. In these people, measurement of beta-cell status could assist with choice of appropriate therapy to delay or potentially reverse beta-cell dysfunction and the progression of T2D.


Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Células Secretoras de Insulina/fisiologia , Biomarcadores , Peptídeo C/sangue , Peptídeo C/urina , Diabetes Mellitus Tipo 2/tratamento farmacológico , Progressão da Doença , Hemoglobina A Glicada , Humanos , Hipoglicemiantes/uso terapêutico , Incretinas/uso terapêutico , Insulina/uso terapêutico , Resistência à Insulina/fisiologia , Estresse Oxidativo/fisiologia
17.
Nat Rev Endocrinol ; 16(7): 349-362, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32398822

RESUMO

Loss of functional ß-cell mass is the key mechanism leading to the two main forms of diabetes mellitus - type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). Understanding the mechanisms behind ß-cell failure is critical to prevent or revert disease. Basic pathogenic differences exist in the two forms of diabetes mellitus; T1DM is immune mediated and T2DM is mediated by metabolic mechanisms. These mechanisms differentially affect early ß-cell dysfunction and eventual fate. Over the past decade, major advances have been made in the field, mostly delivered by studies on ß-cells in human disease. These advances include studies of islet morphology and human ß-cell gene expression in T1DM and T2DM, the identification and characterization of the role of T1DM and T2DM candidate genes at the ß-cell level and the endoplasmic reticulum stress signalling that contributes to ß-cell failure in T1DM (mostly IRE1 driven) and T2DM (mostly PERK-eIF2α dependent). Here, we review these new findings, focusing on studies performed on human ß-cells or on samples obtained from patients with diabetes mellitus.


Assuntos
Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Insuficiência Pancreática Exócrina/etiologia , Células Secretoras de Insulina/fisiologia , Animais , Diabetes Mellitus Tipo 1/etiologia , Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 2/etiologia , Diabetes Mellitus Tipo 2/patologia , Insuficiência Pancreática Exócrina/fisiopatologia , Humanos , Células Secretoras de Insulina/patologia , Transdução de Sinais/fisiologia
18.
Diabetes Res Clin Pract ; 164: 108152, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32360707

RESUMO

INTRODUCTION: Glycemic control plays an important role in diabetes management, and self-monitoring of blood glucose (SMBG) is critical to achieving good glycemic control. However, there are few studies about the relationship between SMBG-estimated glycemic indices and ß-cell function. Here we investigated the association between glucose variation indices estimated by SMBG and ß-cell function among Chinese patients with type 2 diabetes mellitus (T2DM). METHODS: In this cross­sectional study, 397 patients with T2DM were recruited from February 2015 to October 2016. ß-cell function was monitored using the Homeostasis Model Assessment 2 (HOMA2)-%ß index. The parameters evaluated by SMBG were the mean blood glucose (MBG), standard deviation of MBG (SDBG), largest amplitude of glycemic excursions (LAGE), and postprandial glucose excursion (PPGE). RESULTS: HOMA2-%ß was negatively correlated with SDBG, LAGE, PPGE, and MBG (r = -0.350, -0.346, -0.178, and -0.631, respectively; all p < 0.01). After adjusting for confounding characteristics (diabetic duration, triglyceride, total cholesterol, fasting C-peptide, HOMA2-insulin resistance index, hypoglycemia, and diabetic treatments) and glycated hemoglobin A1c on a continuous scale, odds ratios of SDBG, LAGE, PPGE, and MBG between the patients in the lowest and highest HOMA2-%ß quartiles were 2.02 (1.14-3.57), 1.24 (1.04-1.49), 1.13 (0.86-1.51), and 2.26 (1.70-3.00). HOMA2-%ß was independently associated with SDBG, LAGE, and MBG. CONCLUSIONS: Increased SDBG and LAGE assessed by SMBG are associated with ß-cell dysfunction in Chinese patients with T2DM.


Assuntos
Automonitorização da Glicemia/métodos , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Índice Glicêmico/fisiologia , Células Secretoras de Insulina/fisiologia , Adulto , Grupo com Ancestrais do Continente Asiático , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
19.
Nat Commun ; 11(1): 2584, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32444635

RESUMO

Interferon-α (IFNα), a type I interferon, is expressed in the islets of type 1 diabetic individuals, and its expression and signaling are regulated by T1D genetic risk variants and viral infections associated with T1D. We presently characterize human beta cell responses to IFNα by combining ATAC-seq, RNA-seq and proteomics assays. The initial response to IFNα is characterized by chromatin remodeling, followed by changes in transcriptional and translational regulation. IFNα induces changes in alternative splicing (AS) and first exon usage, increasing the diversity of transcripts expressed by the beta cells. This, combined with changes observed on protein modification/degradation, ER stress and MHC class I, may expand antigens presented by beta cells to the immune system. Beta cells also up-regulate the checkpoint proteins PDL1 and HLA-E that may exert a protective role against the autoimmune assault. Data mining of the present multi-omics analysis identifies two compound classes that antagonize IFNα effects on human beta cells.


Assuntos
Processamento Alternativo , Células Secretoras de Insulina/fisiologia , Interferon-alfa/metabolismo , Interferon-alfa/farmacologia , Processamento Alternativo/efeitos dos fármacos , Células Cultivadas , Cromatina/efeitos dos fármacos , Cromatina/metabolismo , Mineração de Dados , Diabetes Mellitus Tipo 1/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes , Humanos , Células Secretoras de Insulina/efeitos dos fármacos , Mapas de Interação de Proteínas , Proteômica , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Sítio de Iniciação de Transcrição
20.
Diabetes ; 69(6): 1219-1231, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32245798

RESUMO

Swi-independent 3a and 3b (Sin3a and Sin3b) are paralogous transcriptional coregulators that direct cellular differentiation, survival, and function. Here, we report that mouse Sin3a and Sin3b are coproduced in most pancreatic cells during embryogenesis but become much more enriched in endocrine cells in adults, implying continued essential roles in mature endocrine cell function. Mice with loss of Sin3a in endocrine progenitors were normal during early postnatal stages but gradually developed diabetes before weaning. These physiological defects were preceded by the compromised survival, insulin-vesicle packaging, insulin secretion, and nutrient-induced Ca2+ influx of Sin3a-deficient ß-cells. RNA sequencing coupled with candidate chromatin immunoprecipitation assays revealed several genes that could be directly regulated by Sin3a in ß-cells, which modulate Ca2+/ion transport, cell survival, vesicle/membrane trafficking, glucose metabolism, and stress responses. Finally, mice with loss of both Sin3a and Sin3b in multipotent embryonic pancreatic progenitors had significantly reduced islet cell mass at birth, caused by decreased endocrine progenitor production and increased ß-cell death. These findings highlight the stage-specific requirements for the presumed "general" coregulators Sin3a and Sin3b in islet ß-cells, with Sin3a being dispensable for differentiation but required for postnatal function and survival.


Assuntos
Cálcio/metabolismo , Diabetes Mellitus/metabolismo , Células Secretoras de Insulina/fisiologia , Proteínas Repressoras/metabolismo , Complexo Correpressor Histona Desacetilase e Sin3/metabolismo , Envelhecimento , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Sobrevivência Celular , Diabetes Mellitus/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Homeostase , Masculino , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Proteínas Repressoras/genética , Complexo Correpressor Histona Desacetilase e Sin3/genética
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