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1.
Life Sci ; 235: 116858, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31505195

RESUMO

AIMS: The current study was conducted to investigate the potential protective effects of hesperidin and its possible mechanisms of action on pancreatic ß-cells in diabetes. MAIN METHODS: Male Sprague Dawley rats were made diabetic using 65 mg/kg intraperitoneal injection of streptozotocin, and then administered daily with 100 mg/kg of hesperidin over 4 weeks. On conclusion of the experiment, blood and pancreatic tissue were collected to determine the function of ß-cells, apoptosis, oxidative stress, ER stress, and inflammation. KEY FINDINGS: Treatment of diabetic rats with hesperidin, significantly decreased fasting blood glucose and food intake, along with increased body weight, serum and pancreatic insulin levels, and pancreatic-duodenal homeobox-1 (PDX-1) protein expression. The beneficial roles of hesperidin on diabetic pancreatic ß-cells exhibited an increment in antioxidant SOD and GPx activities, and a decrement in nitrotyrosine as well as malondialdehyde (MDA) levels. Additionally, the elevated concentration of TNF-α and expressions of ER stress maker GRP78 and CHOP proteins in the pancreas of diabetic rats were significantly diminished by hesperidin treatment. Furthermore, hesperidin effectively modulated expressions of apoptosis-regulatory proteins in diabetic rat pancreas, as revealed by upregulating anti-apoptotic Bcl-xL; with a concomitant downregulating pro-apoptotic Bax, cleaved caspase-3, and inhibiting the activation of DNA repair protein poly (ADP-ribose) polymerase (PARP). SIGNIFICANCE: Collectively, these findings suggest that hesperidin may have the potential to protect pancreatic ß-cells and improve their function by suppressing oxidative and ER stress, along with activating its antioxidant, anti-inflammatory, and anti-apoptotic effects.


Assuntos
Apoptose/efeitos dos fármacos , Diabetes Mellitus Experimental/prevenção & controle , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Hesperidina/farmacologia , Células Secretoras de Insulina/metabolismo , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Proteínas de Choque Térmico/metabolismo , Proteínas de Homeodomínio/biossíntese , Inflamação , Insulina/sangue , Insulina/metabolismo , Masculino , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Pâncreas/metabolismo , Substâncias Protetoras/farmacologia , Ratos , Superóxido Dismutase/metabolismo , Transativadores/biossíntese , Fator de Transcrição CHOP/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo
2.
Gene ; 715: 144028, 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31374326

RESUMO

BACKGROUND: Type 2 diabetes (T2D) is a complex polygenic disease with unclear mechanism. In an attempt to identify novel genes involved in ß-cell function, we harness a bioinformatics method called Loss-of-function tool (LoFtool) gene score. METHODS: RNA-sequencing data from human islets were used to cross-reference genes within the 1st quartile of most intolerant LoFtool score with the 100th most expressed genes in human islets. Out of these genes, GNAS and EEF1A1 genes were selected for further investigation in diabetic islets, metabolic tissues along with their correlation with diabetic phenotypes. The influence of GNAS and EEF1A1 on insulin secretion and ß-cell function were validated in INS-1 cells. RESULTS: A comparatively higher expression level of GNAS and EEF1A1 was observed in human islets than fat, liver and muscle tissues. Furthermore, diabetic islets displayed a reduced expression of GNAS, but not of EEF1A, compared to non-diabetic islets. The expression of GNAS was positively correlated with insulin secretory index, GLP1R, GIPR and inversely correlated with HbA1c. Diabetic human islets displayed a reduced cAMP generation and insulin secretory capacity in response to glucose. Moreover, siRNA silencing of GNAS in INS-1 cells reduced insulin secretion, insulin content, and cAMP production. In addition, the expression of Insulin, PDX1, and MAFA was significantly down-regulated in GNAS-silenced cells. However, cell viability and apoptosis rate were unaffected. CONCLUSION: LoFtool is a powerful tool to identify genes associated with pancreatic islets dysfunction. GNAS is a crucial gene for the ß-cell insulin secretory capacity.


Assuntos
Cromograninas/biossíntese , Subunidades alfa Gs de Proteínas de Ligação ao GTP/biossíntese , Regulação da Expressão Gênica , Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Idoso , Animais , Linhagem Celular , Cromograninas/genética , AMP Cíclico/genética , AMP Cíclico/metabolismo , Feminino , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Humanos , Células Secretoras de Insulina/citologia , Masculino , Pessoa de Meia-Idade , Especificidade de Órgãos , Fator 1 de Elongação de Peptídeos/genética , Fator 1 de Elongação de Peptídeos/metabolismo , Ratos
3.
Life Sci ; 233: 116704, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31369761

RESUMO

AIMS: Doxorubicin, an anticancer drug, has a toxic effect on many tissues such as heart, pancreas, liver, kidney, and testis. The aim of current study is to investigate whether melatonin would be protective in doxorubicin-induced beta (ß) cell toxicity via HMGB1/TLR2/TLR4/MAPK/NF-қB signaling pathway. MAIN METHODS: Human pancreatic ß cell (1.1B4) was used in the present study. Four experimental groups were created as control, melatonin (10 µM), doxorubicin (2 µM) and the combination of melatonin with doxorubicin. Following 24-h treatment, Mitogen-activated protein kinase (MAPKs), Toll like receptors (TLRs) including TLR2 and TLR4, pro-and anti-apoptotic protein expression levels were determined by western blotting. Total antioxidant (TAS), oxidant status (TOS) and oxidative stress index (OSI) of the cells as well as superoxide dismutase (SOD) levels were determined. Active caspase-8 activity was measured and TUNEL staining was performed to study apoptotic pathways. Mitochondrial membrane potential (MMP), some protein expressions and F-actin distribution were analyzed. KEY FINDINGS: Doxorubicin caused to depolarize MMP, resulting in enhancing apoptosis by activation of caspase-8 via MAPKs/NF-кB pathway via elevation of TOS and decreasing TAS. Also, doxorubicin destroyed F-actin distribution and elevated TLR2 and some apoptotic proteins, including Bax. However, co-treatment of melatonin with doxorubicin could reverse depolarization of MMP and inhibition of apoptosis through MAPK/NF-кB signaling by decreasing TOS and increasing TAS. The co-treatment reversed the alternations of TLR2, TLR4, MAPKs and apoptotic protein expressions induced by doxorubicin. SIGNIFICANCE: Melatonin could be a good candidate against pancreatic ß cell toxicity-induced by doxorubicin through TLR2/TLR4/MAPK/NF-кB pathways.


Assuntos
Doxorrubicina/efeitos adversos , Células Secretoras de Insulina/efeitos dos fármacos , Melatonina/farmacologia , Substâncias Protetoras/farmacologia , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Antibióticos Antineoplásicos/efeitos adversos , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Células Cultivadas , Proteína HMGB1/metabolismo , Humanos , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , NF-kappa B/metabolismo , Oxidantes/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Receptor 2 Toll-Like/genética , Receptor 4 Toll-Like/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
4.
Biol Res ; 52(1): 44, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31426858

RESUMO

BACKGROUND: Free fatty acid receptor 1 (FFAR1) is G-protein coupled receptor predominantly expressed in pancreatic ß-cells that is activated by a variety of free fatty acids (FFAs). Once activated, it promotes glucose-stimulated insulin secretion (GSIS). However, increased levels of FFAs lead to lipotoxicity, inducing loss of ß-cell function. FFAR1 plays a key role in the development of type 2 diabetes (T2D), and previous studies have indicated the importance of developing anti-diabetic therapies against FFAR1, although its role in the regulation of ß-cell function remains unclear. The present study investigated the role of FFAR1 under lipotoxic conditions using palmitic acid (PA). The rat insulinoma 1 clone 832/13 (INS-1 832/13) cell line was used as a model as it physiologically resembles native pancreatic ß-cells. Key players of the insulin signaling pathway, such as mTOR, Akt, IRS-1, and the insulin receptor (INSR1ß), were selected as candidates to be analyzed under lipotoxic conditions. RESULTS: We revealed that PA-induced lipotoxicity affected GSIS in INS-1 cells and negatively modulated the activity of both IRS-1 and Akt. Reduced phosphorylation of both IRS-1 S636/639 and Akt S473 was observed, in addition to decreased expression of both INSR1ß and FFAR1. Moreover, transient knockdown of FFAR1 led to a reduction in IRS-1 mRNA expression and an increase in INSR1ß mRNA. Finally, PA affected localization of FFAR1 from the cytoplasm to the perinucleus. CONCLUSIONS: In conclusion, our study suggests a novel regulatory involvement of FFAR1 in crosstalk with mTOR-Akt and IRS-1 signaling in ß-cells under lipotoxic conditions.


Assuntos
Células Secretoras de Insulina/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Ácido Palmítico/toxicidade , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Apoptose , Linhagem Celular , Células Secretoras de Insulina/metabolismo , Ratos , Transdução de Sinais
5.
Life Sci ; 232: 116612, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31260687

RESUMO

AIMS: Accumulating evidence suggest that endoplasmic reticulum (ER) stress is an important mechanism underlying the development of diabetes. We have reported that sustained treatment with N-methyl-d-aspartate (NMDA) results in apoptotic ß-cell death and impairs insulin secretion. However, the molecular mechanism responsible for NMDA-induced ß-cell dysfunction remains largely obscure. Thus, this study aimed to determine whether sustained activation of NMDA receptors (NMDARs) causes ß-cell dysfunction through ER stress. MAIN METHODS: Primary mouse islets and MIN6 mouse pancreatic ß-cells were treated with NMDA for 24 h or high-glucose for 72 h. After the treatment, glucose-stimulated insulin secretion (GSIS) and the expression of ER stress markers were measured, respectively. In vivo, the expression of ER stress markers was measured in the pancreas of diabetic mice treated with or without NMDARs inhibitor Memantine. KEY FINDINGS: NMDA treatment caused an increase in the expression of ER stress markers (ATF4, CHOP, GRP78, and Xbp1s) in primary islets. While, tauroursodeoxycholic acid (TUDCA), an inhibitor of ER stress, significantly attenuated NMDA-induced ß-cell dysfunction, including the loss of glucose-stimulated insulin secretion and reduction of pancreas duodenum homeobox factor-1 (Pdx-1) mRNA expression, a transcription factor regulating insulin synthesis. Besides, NMDA-induced ER stress strongly promoted pro-inflammatory cytokines synthesis (IL-1ß and TNF-α) in ß cells. Interestingly, knockdown of CHOP attenuated ß-cell dysfunction evoked by NMDA. Furthermore, we demonstrated that blockade of NMDARs ameliorated high-glucose-induced ER stress in vitro and in vivo. SIGNIFICANCE: This study confirms that ER stress is actively involved in the activation of NMDARs-related ß-cell dysfunction.


Assuntos
Estresse do Retículo Endoplasmático/fisiologia , Células Secretoras de Insulina/metabolismo , Fator de Transcrição CHOP/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Diabetes Mellitus Experimental/metabolismo , Modelos Animais de Doenças , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Glucose/metabolismo , Proteínas de Choque Térmico/metabolismo , Insulina/metabolismo , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , N-Metilaspartato/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Transdução de Sinais , Proteína 1 de Ligação a X-Box/metabolismo
6.
Cell Biochem Funct ; 37(5): 368-376, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31215684

RESUMO

The growing evidence shows that in the early stage of type 2 diabetes mellitus (T2DM) development, when challenged by hyperglycemia and/or insulin resistance, pancreatic islets would produce more insulin to maintain the balance of blood sugar, but at the same time, endoplasmic reticulum (ER) stress will be initiated for the reason of over-compensation, which might be a crucial caused factor of dysfunction and death of pancreatic beta cell. In this study, we showed that high glucose induced a remarkably unfolded protein response (UPR) with the phosphorylation of PERK/eIF2α and IRE1α in INS-1 cells, but geniposide prevented the role of high glucose on the phosphorylation of PERK/eIF2α and IRE1α, respectively. Although inhibition of Txnip expression by siRNA had no significant effect on geniposide-regulating UPR, PERK and IRE1α were associated with geniposide-regulating Txnip degradation and glucose-stimulated insulin secretion (GSIS) in high glucose-cultured INS-1 cells. All these data suggest that geniposide might be an important regulator of ER stress and GSIS, and a promising compound for the treatment of T2DM. SIGNIFICANCE OF THE STUDY: Mounting evidence indicates that endoplasmic reticulum (ER) stress plays an essential role to maintain the normal cellular functions and dysfunction. In this study, we revealed that geniposide might be an important regulator of ER stress and glucose-stimulated insulin secretion in pancreatic beta cells.


Assuntos
Glucose/metabolismo , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Iridoides/farmacologia , Resposta a Proteínas não Dobradas/fisiologia , Animais , Linhagem Celular , Células Secretoras de Insulina/metabolismo , Ratos
7.
Int J Mol Sci ; 20(11)2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151172

RESUMO

The adipocyte hormone leptin was first recognized for its actions in the central nervous system to regulate energy homeostasis but has since been shown to have direct actions on peripheral tissues. In pancreatic ß-cells leptin suppresses insulin secretion by increasing KATP channel conductance, which causes membrane hyperpolarization and renders ß-cells electrically silent. However, the mechanism by which leptin increases KATP channel conductance had remained unresolved for many years following the initial observation. Recent studies have revealed that leptin increases surface abundance of KATP channels by promoting channel trafficking to the ß-cell membrane. Thus, KATP channel trafficking regulation has emerged as a mechanism by which leptin increases KATP channel conductance to regulate ß-cell electrical activity and insulin secretion. This review will discuss the leptin signaling pathway that underlies KATP channel trafficking regulation in ß-cells.


Assuntos
Secreção de Insulina , Células Secretoras de Insulina/metabolismo , Canais KATP/metabolismo , Leptina/metabolismo , Animais , Biomarcadores , Glucose/metabolismo , Humanos , Ligação Proteica , Transporte Proteico , Transdução de Sinais
8.
Artif Cells Nanomed Biotechnol ; 47(1): 2379-2388, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31184222

RESUMO

Diabetes mellitus (DM) is a metabolic disorder that seriously harms human health. Notoginsenoside R1 (NGR1) can be used in various diseases. We explored consequents of NGR1 on tumour necrosis factor (TNF)-α-stimulated Min6 and rat primary islets ß cells. The results were that TNF-α significantly cut down cell activity, raised cell apoptosis and iNOS expression and decreased insulin secretion in Min6 and rat primary islets ß cells. NGR1 alleviated TNF-α-treated cell dysfunctions. In addition, miR-29a was positively regulated by NGR1 in TNF-α-treated Min6 and rat primary islets ß cells. miR-29a knockdown damaged protection roles of NGR1 through cutting down cell activity and insulin secretion, raising apoptosis and iNOS in TNF-α-treated Min6 and rat primary islets ß cells. The phosphorylation of Wnt3a, ß-catenin and the rate of p/t-AKT/PI3K was all increased, while p/t-GSK3ß was decreased by the administration with NGR1. In conclusion, NGR1 alleviated TNF-α-stimulated Min6 and rat primary islets ß cells apoptosis and worn roles via positively regulating miR-29a. This process might be through actuation of Wnt/ß-catenin and PI3K/AKT/GSK3ß signal ways.


Assuntos
Apoptose/efeitos dos fármacos , Ginsenosídeos/farmacologia , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , MicroRNAs/genética , Fator de Necrose Tumoral alfa/farmacologia , Regulação para Cima/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Glicogênio Sintase Quinase 3 beta/metabolismo , Células Secretoras de Insulina/metabolismo , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Via de Sinalização Wnt/efeitos dos fármacos
9.
Nat Commun ; 10(1): 2474, 2019 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-31171772

RESUMO

Diabetes is a global health problem caused primarily by the inability of pancreatic ß-cells to secrete adequate levels of insulin. The molecular mechanisms underlying the progressive failure of ß-cells to respond to glucose in type-2 diabetes remain unresolved. Using a combination of transcriptomics and proteomics, we find significant dysregulation of major metabolic pathways in islets of diabetic ßV59M mice, a non-obese, eulipidaemic diabetes model. Multiple genes/proteins involved in glycolysis/gluconeogenesis are upregulated, whereas those involved in oxidative phosphorylation are downregulated. In isolated islets, glucose-induced increases in NADH and ATP are impaired and both oxidative and glycolytic glucose metabolism are reduced. INS-1 ß-cells cultured chronically at high glucose show similar changes in protein expression and reduced glucose-stimulated oxygen consumption: targeted metabolomics reveals impaired metabolism. These data indicate hyperglycaemia induces metabolic changes in ß-cells that markedly reduce mitochondrial metabolism and ATP synthesis. We propose this underlies the progressive failure of ß-cells in diabetes.


Assuntos
Diabetes Mellitus Experimental/genética , Diabetes Mellitus Tipo 2/genética , Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , Mitocôndrias/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Perfilação da Expressão Gênica , Gluconeogênese , Glicólise , Secreção de Insulina , Metabolômica , Camundongos , Camundongos Transgênicos , NAD/metabolismo , Fosforilação Oxidativa , Consumo de Oxigênio , Canais de Potássio Corretores do Fluxo de Internalização/genética , Proteômica
10.
Biochemistry (Mosc) ; 84(6): 637-643, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31238863

RESUMO

Taking into account a special role of pancreatic ß-cells in the development of diabetes mellitus, the effects of peroxiredoxin 6 (Prx6) on the viability and functional activity of rat insulinoma RIN-m5F ß-cells were studied under diabetes-simulating conditions. For this purpose, the cells were cultured at elevated glucose concentrations or in the presence of pro-inflammatory cytokines (TNF-α and IL-1) known for their special role in the cytotoxic autoimmune response in diabetes. It was found that the increased glucose concentration of 23-43 mM caused death of 20-60% ß-cells. Prx6 added to cells significantly reduced the level of reactive oxygen species and protected the RIN-m5F ß-cells from hyperglycemia, reducing the death of these cells by several fold. A measurement of insulin secretion by the RIN-m5F ß-cells showed a significant stimulatory effect of Prx6 on the insulin-producing activity of pancreatic ß-cells. It should be noted that the stimulatory activity of Prx6 was detected during culturing the cells under both normal and unfavorable conditions. The regulation of the NF-κB signaling cascade could be one of the mechanisms of Prx6 action on ß-cells, in particular, through activation of RelA/p65 phosphorylation at Ser536.


Assuntos
Citocinas/toxicidade , Glucose/toxicidade , Células Secretoras de Insulina/efeitos dos fármacos , Peroxirredoxina VI/fisiologia , Animais , Morte Celular/fisiologia , Linhagem Celular Tumoral , Sobrevivência Celular/fisiologia , Citocinas/metabolismo , Glucose/metabolismo , Mediadores da Inflamação/metabolismo , Insulina/biossíntese , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Interleucina-1/metabolismo , NF-kappa B/metabolismo , Fosforilação , Ratos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo
11.
Analyst ; 144(12): 3765-3772, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31089611

RESUMO

Investigation of the functions of insulin-secreting cells in response to glucose in single-living cells is essential for improving our knowledge on the pathogenesis of diabetes. Therefore, it is desired to develop a new convenient method that enables the direct detection of insulin secreted from single-living cells. Here, insulin-sensor-cells expressing a protein-based insulin-detecting probe immobilized on the extracellular membrane were developed to evaluate the insulin-secretion response in single-living pancreatic ß cells. The protein-based insulin-detecting probe (NαLY) was composed of a bioluminescent protein (nano-luc), the αCT segment of the insulin receptor, L1 and CR domains of the insulin receptor, and a fluorescent protein (YPet). NαLY exhibited a bioluminescence resonance energy transfer (BRET) signal in response to insulin; thus, cells of Hepa1-6 line were genetically engineered to express NαLY on the extracellular membrane. The cells were found to act as insulin-sensor-cells, exhibiting a BRET signal in response to insulin. When the insulin-sensor-cells and pancreatic ß cells (MIN6 cell line) were cocultured and stimulated with glucose, insulin-sensor-cells nearby pancreatic ß cells showed the spike-shaped BRET signal response, whereas the insulin-sensor-cells close to one pancreatic ß cell did not exhibit such signal response. However, all the insulin-sensor-cells showed a gradual increase in BRET signals, which were presumably attributed to the increase in insulin concentrations in the culture dish, confirming the function of these insulin-sensor-cells. Therefore, we demonstrated that heterogenetic insulin secretion in single-living pancreatic ß cells could be measured directly using the insulin sensor cells.


Assuntos
Técnicas de Transferência de Energia por Ressonância de Bioluminescência/métodos , Técnicas Biossensoriais/métodos , Células Secretoras de Insulina/metabolismo , Insulina/análise , Análise de Célula Única/métodos , Animais , Linhagem Celular Tumoral , Técnicas de Cocultura/métodos , Fluorescência , Glucose/metabolismo , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Engenharia de Proteínas/métodos , Receptor de Insulina/genética , Receptor de Insulina/metabolismo
12.
Chemistry ; 25(39): 9287-9294, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31087418

RESUMO

The cyclic depsipeptide cereulide toxin it is a very well-known potassium electrogenic ionophore particularly sensitive to pancreatic beta cells. The mechanistic details of its specific activity are unknown. Here, we describe a series of synthetic substituted cereulide potassium ionophores that cause impressive selective activation of glucose-induced insulin secretion in a constitutive manner in rat insulinoma INS1E cells. Our study demonstrates that the different electroneutral K+ transport mechanism exhibited by the anionic mutant depsipeptides when compared with classical electrogenic cereulides can have an important impact of pharmacological value on glucose-stimulated insulin secretion.


Assuntos
Depsipeptídeos/farmacologia , Secreção de Insulina/efeitos dos fármacos , Ionóforos/química , Potássio/química , Animais , Transporte Biológico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Depsipeptídeos/síntese química , Depsipeptídeos/química , Glucose/farmacologia , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Microscopia Confocal , Potássio/metabolismo , Ratos
13.
Arch Endocrinol Metab ; 63(3): 222-227, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31066759

RESUMO

OBJECTIVE: Type 2 diabetes (T2DM) is characterized by the progressive deterioration of pancreatic islet ß-cell function over time and insulin resistance. Knowing more about the differences in pancreatic islet function in T2DM patients who have had diabetes for different lengths of time can help improve therapy for T2DM. SUBJECTS AND METHODS: We conducted a cross-sectional study to compare islet ß-cell function and insulin resistance in T2DM patients (n = 3,254) who had had diabetes for different lengths of time and those in normal controls (n = 794) using ANOVA and LSD analysis. RESULTS: We found that compared with that in normal controls, HOMA-ß in T2DM patients with a history of diabetes of less than 1 year was lower (approximately 52% of that of normal controls, p = 0.003), while HOMA-IR in these patients was higher (approximately 50% of that of normal controls, p = 0.007). Compared with that in other diabetic patients, HOMA-ß in patients with a history of diabetes of more than 30 years was the lowest. HOMA-IR in patients with a history of diabetes of between 20 and 30 years was lower than that in other diabetic patients (p < 0.05). CONCLUSIONS: There were obvious decreases in HOMA-ß and increases in HOMA-IR in T2DM patients with a history of diabetes of less than 1 year compared with those in normal controls. Therefore, early screening and intervention for T2DM might help improve islet function and delay the progression of diabetes.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Homeostase/fisiologia , Resistência à Insulina , Células Secretoras de Insulina/metabolismo , Adulto , Idoso , Glicemia/análise , Índice de Massa Corporal , Estudos de Casos e Controles , Estudos Transversais , Diabetes Mellitus Tipo 2/fisiopatologia , Teste de Tolerância a Glucose , Humanos , Ilhotas Pancreáticas/metabolismo , Pessoa de Meia-Idade , Modelos Biológicos , Fatores de Tempo
14.
Int J Mol Sci ; 20(9)2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31035653

RESUMO

Endogenous cannabinoids (ECs) are lipid-signaling molecules that specifically bind to cannabinoid receptor types 1 and 2 (CB1R and CB2R) and are highly expressed in central and many peripheral tissues under pathological conditions. Activation of hepatic CB1R is associated with obesity, insulin resistance, and impaired metabolic function, owing to increased energy intake and storage, impaired glucose and lipid metabolism, and enhanced oxidative stress and inflammatory responses. Additionally, blocking peripheral CB1R improves insulin sensitivity and glucose metabolism and also reduces hepatic steatosis and body weight in obese mice. Thus, targeting EC receptors, especially CB1R, may provide a potential therapeutic strategy against obesity and insulin resistance. There are many CB1R antagonists, including inverse agonists and natural compounds that target CB1R and can reduce body weight, adiposity, and hepatic steatosis, and those that improve insulin sensitivity and reverse leptin resistance. Recently, the use of CB1R antagonists was suspended due to adverse central effects, and this caused a major setback in the development of CB1R antagonists. Recent studies, however, have focused on development of antagonists lacking adverse effects. In this review, we detail the important role of CB1R in hepatic insulin resistance and the possible underlying mechanisms, and the therapeutic potential of CB1R targeting is also discussed.


Assuntos
Resistência à Insulina , Receptor CB1 de Canabinoide/metabolismo , Animais , Suscetibilidade a Doenças , Humanos , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Metabolismo dos Lipídeos , Terapia de Alvo Molecular , Músculo Esquelético/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Especificidade de Órgãos , Transdução de Sinais
15.
Eur J Pharmacol ; 854: 372-379, 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31054273

RESUMO

G-protein coupled receptor 55 (GPR55) is an orphan G-protein coupled receptor, which is activated by endocannabinoids and lipid transmitters. Recently, GPR55 was shown to play a role in glucose and energy homeostasis, and insulin secretion is essential to maintain glucose homeostasis in the body. In Type 2 Diabetes Mellitus (T2DM), chronic insulin resistance and a progressive decline in ß-cell function result in ß-cell dysfunction, this leads to defect in insulin secretion, which is the key process in the development and progression of T2DM. GPR55 agonists were shown to increase insulin secretion, however the underlying mechanisms were not fully understood. Therefore the aim of the present study was to examine the effects of potent GPR55 agonists, O-1602 and abnormal cannabidiol (Abn-CBD), on glucose-induced insulin secretion in a mouse pancreatic ß-cell line, MIN6, and the underlying mechanisms with a focus on intracellular calcium (Ca2+). Our results demonstrated that O-1602 and Abn-CBD increased glucose-induced insulin secretion in MIN6 cells, which was abolished by a PLC inhibitor, U73122. Glucose-induced Ca2+ transients were enhanced by O-1602 and Abn-CBD, and this was significantly reduced by U73122 and inositol trisphosphate (IP3) receptor inhibitors, 2-aminoethoxydiphenyl borate (2-APB) and xestospongin C, as well as by Y-27632, a Rho-associated protein kinase (ROCK) inhibitor. Interestingly, O-1602 and Abn-CBD could directly induce intracellular Ca2+ transients through IP3-mediated Ca2+ release. In conclusion, GPR55 agonists increased insulin secretion through calcium mobilisation from IP3-sensitive ER stores in ß-cells.


Assuntos
Cálcio/metabolismo , Fosfatos de Inositol/metabolismo , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Receptores de Canabinoides/metabolismo , Animais , Canabidiol/análogos & derivados , Canabidiol/farmacologia , Linhagem Celular Tumoral , Glucose/farmacologia , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Células Secretoras de Insulina/citologia , Camundongos , Fosfolipase C beta/metabolismo , Resorcinóis/farmacologia , Regulação para Cima/efeitos dos fármacos , Quinases Associadas a rho/metabolismo
16.
Molecules ; 24(10)2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31091684

RESUMO

Venom from mammals, amphibians, snakes, arachnids, sea anemones and insects provides diverse sources of peptides with different potential medical applications. Several of these peptides have already been converted into drugs and some are still in the clinical phase. Diabetes type 2 is one of the diseases with the highest mortality rate worldwide, requiring specific attention. Diverse drugs are available (e.g., Sulfonylureas) for effective treatment, but with several adverse secondary effects, most of them related to the low specificity of these compounds to the target. In this context, the search for specific and high-affinity compounds for the management of this metabolic disease is growing. Toxins isolated from animal venom have high specificity and affinity for different molecular targets, of which the most important are ion channels. This review will present an overview about the electrical activity of the ion channels present in pancreatic ß cells that are involved in the insulin secretion process, in addition to the diversity of peptides that can interact and modulate the electrical activity of pancreatic ß cells. The importance of prospecting bioactive peptides for therapeutic use is also reinforced.


Assuntos
Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Peptídeos/farmacologia , Peçonhas/química , Animais , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Desenvolvimento de Medicamentos , Humanos , Células Secretoras de Insulina/efeitos dos fármacos , Ativação do Canal Iônico/efeitos dos fármacos , Peptídeos/química , Pesquisa Médica Translacional
17.
Mol Med Rep ; 19(6): 5015-5022, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31059088

RESUMO

Sweet taste receptors (STRs) expressed on ß­cells stimulate insulin secretion in response to an increase in the circulating level of glucose, maintaining glucose homeostasis. 3­Deoxyglucosone (3DG), a highly reactive α­dicarbonyl compound, has been previously described as an independent factor associate with the development of prediabetes. In our previous study, pathological plasma levels of 3DG were induced in normal rats with a single intravenous injection of 50 mg/kg 3DG, and an acute rise in circulating 3DG induced glucose intolerance by impairing the function of pancreatic ß­cells. The present study aimed to investigate whether the deleterious effects of pathological plasma levels of 3DG on ß­cell function and insulin secretion were associated with STRs. INS­1 cells, an in vitro model to study rat ß­cells, were treated with various concentrations of 3DG (1.85, 30.84 and 61.68 mM) or lactisole (5 mM). Pancreatic islets were collected from rats 2 h after a single intravenous injection of 50 mg/kg 3DG + 0.5 g/kg glucose. The insulin concentration was measured by ELISA. The protein expression levels of components of the STR signaling pathways were determined by western blot analysis. Treatment with 3DG and 25.5 mM glucose for 1 h significantly reduced insulin secretion by INS­1 cells, which was consistent with the phenotype observed in INS­1 cells treated with the STR inhibitor lactisole. Accordingly, islets isolated from rats treated with 3DG exhibited a significant reduction in insulin secretion following treatment with 25.5 mM glucose. Furthermore, acute exposure of INS­1 cells to 3DG following treatment with 25.5 mM glucose for 1 h significantly reduced the protein expression level of the STR subunit taste 1 receptor member 3 and its downstream factors, transient receptor potential cation channel subfamily M member 5 and glucose transporter 2. Notably, islet tissues collected from rats treated with 3DG exhibited a similar downregulation of these factors. The present results suggested that acute exposure to pathologically relevant levels of 3DG in presence of high physiological levels of glucose decreased insulin secretion from ß­cells by, at least in part, downregulating the STR signaling pathway.


Assuntos
Desoxiglucose/análogos & derivados , Glucose/farmacologia , Secreção de Insulina/efeitos dos fármacos , Receptores Acoplados a Proteínas-G/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Derivados de Benzeno/farmacologia , Células Cultivadas , Desoxiglucose/farmacologia , Regulação para Baixo/efeitos dos fármacos , Transportador de Glucose Tipo 2/metabolismo , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas-G/antagonistas & inibidores , Canais de Cátion TRPM/metabolismo
18.
Int J Mol Sci ; 20(10)2019 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-31109026

RESUMO

Studies using mesenchymal stromal cells (MSCs) as a source of insulin-secreting cells (IPCs) are a promising path in the pursuit for diabetes therapy. Here, we investigate three short-term differentiation protocols in order to generate IPCs from autologous adipose-derived stromal cells (ADSCs) with an expressive insulin-secreting profile in vitro and in vivo, as well as the signaling pathways involved in the chosen differentiation protocols. We extracted and cultured ADSCs and differentiated them into IPCs, using three different protocols with different inductors. Afterwards, the secretory profile was analyzed and IPCs differentiated in exendin-4/activin A medium, which presented the best secretory profile, was implanted in the kidney subcapsular region of diabetic rats. All protocols induced the differentiation, but media supplemented with exendin-4/activin A or resveratrol induced the expression and secretion of insulin more efficiently, and only the exendin-4/activin-A-supplemented medium generated an insulin secretion profile more like ß-cells, in response to glucose. The PI3K/Akt pathway seems to play a negative role in IPC differentiation; however, the differentiation of ADSCs with exendin-4/activin A positively modulated the p38/MAPK pathway. Resveratrol medium activated the Jak/STAT3 pathway and generated IPCs apparently less sensitive to insulin and insulin-like receptors. Finally, the implant of IPCs with the best secretory behavior caused a decrease in hyperglycemia after one-week implantation in diabetic rats. Our data provide further information regarding the generation of IPCs from ADSCs and strengthen evidence to support the use of MSCs in regenerative medicine, specially the use of exendin-4/activin A to produce rapid and effectively IPCs with significant in vivo effects.


Assuntos
Adipócitos/metabolismo , Células Secretoras de Insulina/metabolismo , Tecido Adiposo/citologia , Tecido Adiposo/metabolismo , Animais , Transporte Biológico , Biomarcadores , Diferenciação Celular , Células Cultivadas , Diabetes Mellitus Experimental , Expressão Gênica , Glucose/metabolismo , Imuno-Histoquímica , Insulina/genética , Insulina/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Fenótipo , Ratos , Transdução de Sinais
19.
Nat Immunol ; 20(6): 677-686, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31110312

RESUMO

Consumption of a high-energy Western diet triggers mild adaptive ß cell proliferation to compensate for peripheral insulin resistance; however, the underlying molecular mechanism remains unclear. In the present study we show that the toll-like receptors TLR2 and TLR4 inhibited the diet-induced replication of ß cells in mice and humans. The combined, but not the individual, loss of TLR2 and TLR4 increased the replication of ß cells, but not that of α cells, leading to enlarged ß cell area and hyperinsulinemia in diet-induced obesity. Loss of TLR2 and TLR4 increased the nuclear abundance of the cell cycle regulators cyclin D2 and Cdk4 in a manner dependent on the signaling mediator Erk. These data reveal a regulatory mechanism controlling the proliferation of ß cells in diet-induced obesity and suggest that selective targeting of the TLR2/TLR4 pathways may reverse ß cell failure in patients with diabetes.


Assuntos
Células Secretoras de Insulina/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Receptor 2 Toll-Like/genética , Receptor 4 Toll-Like/genética , Animais , Proliferação de Células , Ciclina D2/metabolismo , Quinase 4 Dependente de Ciclina/metabolismo , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Feminino , Humanos , Insulina/sangue , Insulina/metabolismo , Células Secretoras de Insulina/ultraestrutura , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Sistema de Sinalização das MAP Quinases , Masculino , Camundongos , Camundongos Knockout , Complexos Multiproteicos/metabolismo , Obesidade/tratamento farmacológico , Parabiose , Ligação Proteica , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo
20.
Braz J Med Biol Res ; 52(6): e8344, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31141089

RESUMO

Type 2 diabetes mellitus (T2D) is a common endocrine and metabolic disorder, and poses threats to human health worldwide. Recently, microRNAs (miRNAs) have been suggested to play important roles in the pathophysiology of T2D. In this study, we explored the role of miR-3666 in T2D. miR-3666 was significantly down-regulated in the serum of T2D patients when compared to that of healthy volunteers, and miR-3666 expression level was negatively correlated with blood glucose levels of T2D patients. Overexpression of miR-3666 inhibited cell proliferation, reduced insulin secretion, and promoted cell apoptosis of pancreatic ß-cell line (INS-1 cells). On the other hand, knockdown of miR-3666 had the opposite effects in INS-1 cells. The bio-informatics analysis using TargetScan revealed that adiponectin (ADIPOQ) was a downstream target of miR-3666, and the interaction between miR-3666 and ADIPOQ was validated by luciferase reporter assay. In addition, miR-3666 negatively regulated the mRNA and protein expression of ADIPOQ. Overexpression of ADIPOQ promoted insulin secretion after glucose stimulation, promoted cell proliferation, inhibited cell apoptosis, and partially abolished the effects of miR-3666 overexpression on insulin secretion, cell proliferation, and cell apoptosis of INS-1 cells. In conclusion, our results revealed that miR-3666 inhibited pancreatic cell proliferation, reduced insulin sensitivity, and promoted apoptosis by targeting ADIPOQ.


Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Resistência à Insulina/fisiologia , Células Secretoras de Insulina/fisiologia , MicroRNAs/metabolismo , Adiponectina/genética , Adiponectina/metabolismo , Apoptose , Proliferação de Células , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Citometria de Fluxo , Humanos , Células Secretoras de Insulina/metabolismo , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real
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