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1.
Life Sci ; 258: 118145, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32717270

RESUMO

AIMS: Studies on diabetes mellitus have shown that the phosphoinositide 3-kinase (PI3K)/serine threonine kinase (AKT)/forkhead box protein O1 (FoxO1) signaling pathway can regulate insulin secretion by modulating the expression of pancreatic and duodenal homeobox-1 (PDX-1). Therefore, it was hypothesized that the pathway also played an important role in functional abnormalities of pancreatic islets after severe burns. This study aimed to explore the role and mechanism of the PI3K/AKT/FoxO1/PDX-1 signaling pathway in functional changes of pancreatic islets in rats post severe burns. MAIN METHODS: Rats were grouped, subjected to full thickness burn injuries involving 50% total body surface area (TBSA), and injected intraperitoneally with BPV (HOpic) (0.6 mg/kg) or DMSO (0.55 mg/kg) once a day for three days. Glucose metabolism related indexes were measured by the glucometer, transmission electron microscopy (TEM) and enzyme-linked immunosorbent assay (ELISA). PI3K/AKT/FoxO1/PDX-1 signaling pathway related indexes were detected through immunofluorescence, western blot and RT-qPCR analyses. KEY FINDINGS: Dysglycemia and impaired insulin secretion occurred in rats, the activity of the PI3K/AKT/FoxO1/PDX-1 signaling pathway in the islets fell, and PDX-1 was translocated from the nucleus to the cytoplasm post severe burns. When BPV (HOpic) was used, glucose metabolism and insulin secretion were improved, the activity of the PI3K/AKT/FoxO1/PDX-1 signaling pathway in the islets was up-regulated, and PDX-1 was redistributed from the cytoplasm to the nucleus. SIGNIFICANCE: The activity of the PI3K/AKT/FoxO1/PDX-1 signaling pathway declined following severe burns. When its activity was up-regulated, insulin secretion could be improved, thus ameliorating hyperglycemia.


Assuntos
Queimaduras/patologia , Proteínas de Homeodomínio/metabolismo , Ilhotas Pancreáticas/patologia , Proteínas do Tecido Nervoso/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transativadores/metabolismo , Animais , Queimaduras/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Masculino , Ratos , Ratos Wistar , Transdução de Sinais
2.
PLoS One ; 15(6): e0235052, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584858

RESUMO

INTRODUCTION: 3D printing is being used more extensively in modern biomedicine. One of the problems is selecting a proper crosslinking method of bioprinted material. Amongst currently used techniques we can distinguish: physical crosslinking (e.g. Ca2+ and Sr2+) and chemical crosslinking-the UV light crosslinking causing the biggest discussion. UV radiation is selectively absorbed by DNA, mainly in the UV-B region but also (to some extent) in UV-A and UV-C regions. DNA excitement results in typical photoproducts. The amount of strand breaks may vary depending on the period of exposition, it can also differ when cells undergo incubation after radiation. AIM: The aim of this study was to show whether and how the time of irradiation with 405 nm and 365 nm wavelengths affect DNA damage in cell lines and micro-organs (pancreatic islets). MATERIALS AND METHODS: The degree of DNA damage caused by different wavelengths of radiation (405 nm and 365 nm) was evaluated by a comet assay. The test was performed on fibroblasts, alpha cells, beta cells and porcine pancreatic islets after 24 hours incubation period. Samples without radiation treatment were selected as a control group. Results analysis consisted of determining the percent of cells with damaged DNA and the tail intensity evaluation. RESULTS: The degree of DNA damage in pancreatic islets after exposure to 405 nm wavelength oscillated between 2% and 6% depending on the tested time period (10 - 300 seconds). However, treating islets using 365 nm wavelength resulted in damage up to 50%. This clearly shows significantly less damage when using 405 nm wavelength. Similar results were obtained for the tested cell lines. CONCLUSIONS: Crosslinking with 405 nm is better for pancreatic islets than crosslinking with 365 nm UV light.


Assuntos
Dano ao DNA , Ilhotas Pancreáticas/metabolismo , Raios Ultravioleta/efeitos adversos , Animais , Linhagem Celular Tumoral , Humanos , Ilhotas Pancreáticas/patologia , Camundongos , Suínos
3.
Nutr Metab Cardiovasc Dis ; 30(7): 1216-1226, 2020 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-32482454

RESUMO

BACKGROUND AND AIMS: Successful islet transplantation as a promising treatment of diabetes type 1 is threatened with the loss of islets during the pre-transplant culture due to hypoxia and oxidative stress-induced apoptosis. Therefore, optimization of culture in order to preserve the islets is a critical point. In this study, we investigated the effect of resveratrol, as a cytoprotective agent, on the cultured human islets. METHODS AND RESULTS: Isolated islets were treated with different concentrations of resveratrol for 24 and 72 h. Islets' viability, apoptosis, apoptosis markers, and insulin and C-peptide secretion, along with the production of reactive oxygen species (ROS), hypoxia inducible factor 1 alpha (HIF-1α), and its target genes in the islets were investigated. Our findings showed that the islets were exposed to hypoxia and oxidative stress after isolation and during culture. This insult induced apoptosis and decreased viability during 72 h. The presence of resveratrol significantly attenuated HIF-1α and ROS production, reduced apoptosis, promoted the VEGF secretion, and increased the insulin and C-peptide secretion. In this regard, resveratrol improved the islet's survival and function in the culture period. CONCLUSIONS: Using resveratrol can attenuate the stressful condition for the islets in the pre-transplant culture and subsequently ameliorate their viability and functionality that lead to successful outcome after clinical transplantation.


Assuntos
Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Ilhotas Pancreáticas/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Resveratrol/farmacologia , Adulto , Idoso , Peptídeo C/metabolismo , Hipóxia Celular , Sobrevivência Celular/efeitos dos fármacos , Citoproteção , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Pessoa de Meia-Idade , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Técnicas de Cultura de Tecidos , Fator A de Crescimento do Endotélio Vascular/metabolismo
4.
Metabolism ; 110: 154304, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32599081

RESUMO

The loss of beta-cell functional mass is a necessary and early condition in the development of type 2 diabetes (T2D). In T2D patients, beta-cell function is already reduced by about 50% at diagnosis and further declines thereafter. Beta-cell mass is also reduced in subjects with T2D, and islets from diabetic donors are smaller compared to non-diabetic donors. Thus, beta-cell regeneration and/or preservation of the functional islet integrity should be highly considered for T2D treatment and possibly cure. To date, the available anti-diabetes drugs have been developed as "symptomatic" medications since they act to primarily reduce elevated blood glucose levels. However, a truly efficient anti-diabetes medication, capable to prevent the onset and progression of T2D, should stop beta-cell loss and/or promote the restoration of fully functional beta-cell mass, independently of reducing hyperglycemia and ameliorating glucotoxicity on the pancreatic islets. This review provides a view of the experimental and clinical evidence on the ability of available anti-diabetes drugs to exert protective effects on beta-cells, with a specific focus on human pancreatic islets and clinical trials. Potential explanations for the lack of concordance between evidence of beta-cell protection in vitro and of persistent amelioration of beta-cell function in vivo are also discussed.


Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Ilhotas Pancreáticas/fisiopatologia , Ensaios Clínicos como Assunto , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/etiologia , Humanos , Hipoglicemiantes/uso terapêutico , Células Secretoras de Insulina/efeitos dos fármacos , Ilhotas Pancreáticas/patologia
5.
Nat Commun ; 11(1): 2475, 2020 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-32424134

RESUMO

Autoimmune ß-cell destruction leads to type 1 diabetes, but the pathophysiological mechanisms remain unclear. To help address this void, we created an open-access online repository, unprecedented in its size, composed of large-scale electron microscopy images ('nanotomy') of human pancreas tissue obtained from the Network for Pancreatic Organ donors with Diabetes (nPOD; www.nanotomy.org). Nanotomy allows analyses of complete donor islets with up to macromolecular resolution. Anomalies we found in type 1 diabetes included (i) an increase of 'intermediate cells' containing granules resembling those of exocrine zymogen and endocrine hormone secreting cells; and (ii) elevated presence of innate immune cells. These are our first results of mining the database and support recent findings that suggest that type 1 diabetes includes abnormalities in the exocrine pancreas that may induce endocrine cellular stress as a trigger for autoimmunity.


Assuntos
Bases de Dados como Assunto , Diabetes Mellitus Tipo 1/patologia , Ilhotas Pancreáticas/ultraestrutura , Microscopia Eletrônica , Autoanticorpos/metabolismo , Grânulos Citoplasmáticos/ultraestrutura , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/ultraestrutura , Granulócitos/imunologia , Humanos , Imunidade Inata , Ilhotas Pancreáticas/imunologia , Ilhotas Pancreáticas/patologia , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Doadores de Tecidos
6.
Nat Commun ; 11(1): 2238, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32382089

RESUMO

In type1 diabetes (T1D) autoreactive T-cells infiltrate the islets of Langerhans, depleting insulin-secreting ß-cells (insulitis). Insulitis arises during an asymptomatic phase, prior to clinical diagnosis of T1D. Methods to diagnose insulitis and ß-cell mass changes during this asymptomatic phase are limited, precluding early therapeutic intervention. During T1D the islet microvasculature increases permeability, allowing nanoparticles to access the microenvironment. Contrast enhanced ultrasound (CEUS) uses shell-stabilized gas bubbles to provide acoustic backscatter in vasculature. Here, we report that sub-micron sized 'nanobubble' ultrasound contrast agents can be used to measure increased islet microvasculature permeability and indicate asymptomatic T1D. Through CEUS and histological analysis, pre-clinical models of T1D show accumulation of nanobubbles specifically within pancreatic islets, correlating with insulitis. Importantly, accumulation is detected early in disease progression and decreases with successful therapeutic intervention. Thus, sub-micron sized nanobubble ultrasound contrast agents provide a predicative marker for disease progression and therapeutic reversal early in asymptomatic T1D.


Assuntos
Meios de Contraste , Diabetes Mellitus Tipo 1/diagnóstico por imagem , Diabetes Mellitus Tipo 1/patologia , Animais , Feminino , Humanos , Células Secretoras de Insulina/patologia , Ilhotas Pancreáticas/diagnóstico por imagem , Ilhotas Pancreáticas/patologia , Camundongos , Pâncreas/diagnóstico por imagem , Pâncreas/patologia , Ultrassonografia
7.
Am J Hum Genet ; 106(6): 846-858, 2020 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-32470372

RESUMO

The burden of several common diseases including obesity, diabetes, hypertension, asthma, and depression is increasing in most world populations. However, the mechanisms underlying the numerous epidemiological and genetic correlations among these disorders remain largely unknown. We investigated whether common polymorphic inversions underlie the shared genetic influence of these disorders. We performed an inversion association analysis including 21 inversions and 25 obesity-related traits on a total of 408,898 Europeans and validated the results in 67,299 independent individuals. Seven inversions were associated with multiple diseases while inversions at 8p23.1, 16p11.2, and 11q13.2 were strongly associated with the co-occurrence of obesity with other common diseases. Transcriptome analysis across numerous tissues revealed strong candidate genes for obesity-related traits. Analyses in human pancreatic islets indicated the potential mechanism of inversions in the susceptibility of diabetes by disrupting the cis-regulatory effect of SNPs from their target genes. Our data underscore the role of inversions as major genetic contributors to the joint susceptibility to common complex diseases.


Assuntos
Inversão Cromossômica/genética , Diabetes Mellitus/genética , Predisposição Genética para Doença , Hipertensão/genética , Obesidade/complicações , Obesidade/genética , Polimorfismo Genético , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Cromossomos Humanos Par 16/genética , Cromossomos Humanos Par 8/genética , Conjuntos de Dados como Assunto/normas , Diabetes Mellitus/patologia , Europa (Continente)/etnologia , Feminino , Perfilação da Expressão Gênica , Haplótipos , Humanos , Hipertensão/complicações , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Reprodutibilidade dos Testes , Adulto Jovem
8.
Metabolism ; 107: 154232, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32302619

RESUMO

AIMS: Parasympathetic nerve (PN) signaling plays a crucial role in the maintenance of pancreatic ß-cell volume density (Vß). PN may be pathologically affected in diabetic polyneuropathy (DPN). However, the association between the reduction of PNs in islets and Vß and the therapeutic effects of a DPP4 inhibitor (DPP4i) and an SGLT2 inhibitor (SGLT2i) in nonobese type 2 diabetes mellitus (T2DM) Goto-Kakizaki rats (GK) have not been investigated. MATERIALS AND METHODS: We divided 5-week old male GK and Wistar rats (W) into a DPP4i-treated group (GKTe), SGLT2i-treated group (GKCa), and combination-treated group (GKCaTe). After 25 weeks, the pancreata was pathologically evaluated. RESULTS: Vß in GK was significantly decreased (p < 0.01 vs. W), whereas Vß was the most well preserved in GKCaTe (p < 0.05 vs. GKTe), followed by GKTe (p < 0.05 vs. GK). The decreased amount of PNs in the islets and intraepidermal nerve fiber density (IENFD) in GK was significantly improved in the treated groups compared with GK (p < 0.05 vs. GKCa and GKTe and p < 0.01 vs. GKCaTe). PN density and IENFD were significantly correlated with Vß (r = 0.55, p < 0.01 and r = 0.54, p < 0.01, respectively). IENFD was identified as a surrogate marker for the prediction of Vß (cutoff value, 16.39). CONCLUSIONS: The combination therapy of DPP4i and SGLT2i improved Vß accompanied by PNs density and IENFD. IENFD was proportionally correlated with Vß. Therefore, the prevention of DPN development may be concurrently beneficial for the preservation of Vß in nonobese T2DM.


Assuntos
Canagliflozina/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Neuropatias Diabéticas/tratamento farmacológico , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Hipoglicemiantes/uso terapêutico , Células Secretoras de Insulina/patologia , Pirazóis/uso terapêutico , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Tiazolidinas/uso terapêutico , Animais , Glicemia/metabolismo , Contagem de Células , Diabetes Mellitus Tipo 2/patologia , Quimioterapia Combinada , Hemoglobina A Glicada/análise , Ilhotas Pancreáticas/patologia , Masculino , Pâncreas/patologia , Sistema Nervoso Parassimpático/patologia , Ratos , Ratos Wistar
9.
Adv Exp Med Biol ; 1221: 607-630, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32274728

RESUMO

Type 1 diabetes (T1D) results from autoimmune destruction of insulin-producing beta cells in pancreatic islets. The degradation of the glycosaminoglycan heparan sulfate (HS) by the endo-ß-D-glycosidase heparanase plays a critical role in multiple stages of the disease process. Heparanase aids (i) migration of inflammatory leukocytes from the vasculature to the islets, (ii) intra-islet invasion by insulitis leukocytes, and (iii) selective destruction of beta cells. These disease stages are marked by the solubilization of HS in the subendothelial basement membrane (BM), HS breakdown in the peri-islet BM, and the degradation of HS inside beta cells, respectively. Significantly, healthy islet beta cells are enriched in highly sulfated HS which is essential for their viability, protection from damage by reactive oxygen species (ROS), beta cell function and differentiation. Consequently, mouse and human beta cells but not glucagon-producing alpha cells (which contain less-sulfated HS) are exquisitely vulnerable to heparanase-mediated damage. In vitro, the death of HS-depleted mouse and human beta cells can be prevented by HS replacement using highly sulfated HS mimetics or analogues. T1D progression in NOD mice and recent-onset T1D in humans correlate with increased expression of heparanase by circulating leukocytes of myeloid origin and heparanase-expressing insulitis leukocytes. Treatment of NOD mice with the heparanase inhibitor and HS replacer, PI-88, significantly reduced T1D incidence by 50%, impaired the development of insulitis and preserved beta cell HS. These outcomes identified heparanase as a novel destructive tool in T1D, distinct from the conventional cytotoxic and apoptosis-inducing mechanisms of autoreactive T cells. In contrast to exogenous catalytically active heparanase, endogenous heparanase may function in HS homeostasis, gene expression and insulin secretion in normal beta cells and immune gene expression in leukocytes. In established diabetes, the interplay between hyperglycemia, local inflammatory cells (e.g. macrophages) and heparanase contributes to secondary micro- and macro-vascular disease. We have identified dual activity heparanase inhibitors/HS replacers as a novel class of therapeutic for preventing T1D progression and potentially for mitigating secondary vascular disease that develops with long-term T1D.


Assuntos
Diabetes Mellitus Tipo 1/enzimologia , Glucuronidase/metabolismo , Animais , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/patologia , Glucuronidase/antagonistas & inibidores , Humanos , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/enzimologia , Ilhotas Pancreáticas/patologia
10.
J Vis Exp ; (156)2020 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-32116299

RESUMO

Pancreatic islet transplantation is a well-established therapeutic treatment for type 1 diabetes. The kidney capsule is the most commonly used site for islet transplantation in rodent models. However, the tight kidney capsule limits the transplantation of sufficient islets in large animals and humans. The inguinal subcutaneous white adipose tissue (ISWAT), a new subcutaneous space, was found to be a potentially valuable site for islet transplantation. This site has better blood supply than other subcutaneous spaces. Moreover, the ISWAT accommodates a larger islet mass than the kidney capsule, and transplantation into it is simple. This manuscript describes the procedure of mouse islet isolation and transplantation in the ISWAT site of syngeneic diabetic mouse recipients. Using this protocol, murine pancreatic islets were isolated by standard collagenase digestion and a basement membrane matrix hydrogel was used for fixing the purified islets in the ISWAT site. The blood glucose levels of the recipient mice were monitored for more than 100 days. Islet grafts were retrieved at day 100 after transplantation for histological analysis. The protocol for islet transplantation in the ISWAT site described in this manuscript is simple and effective.


Assuntos
Canal Inguinal/anatomia & histologia , Transplante das Ilhotas Pancreáticas , Modelos Biológicos , Gordura Subcutânea/transplante , Animais , Glicemia/metabolismo , Peso Corporal , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/terapia , Sobrevivência de Enxerto , Humanos , Ilhotas Pancreáticas/patologia , Camundongos Endogâmicos C57BL , Perfusão , Sobrevivência de Tecidos
11.
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
12.
Metabolism ; 104: 154143, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31927009

RESUMO

Insulin deficiency in type 2 diabetes mellitus (DM) involves a decline in both pancreatic ß-cell mass and function. Enhancing ß-cell preservation represents an important therapeutic strategy to treat type 2 DM. Far-infrared (FIR) radiation has been found to induce promyelocytic leukemia zinc finger protein (PLZF) activation to protect the vascular endothelium in diabetic mice. The influence of FIR on ß-cell preservation is unknown. Our previous study reveals that the biologically effective wavelength of FIR is 8-10 µm. In the present study, we investigated the biological effects of FIR (8-10 µm) on both survival and insulin secretion function of ß-cells. FIR reduced pancreatic islets loss and increased insulin secretion in nicotinamide-streptozotocin-induced DM mice, but only promoted insulin secretion in DM PLZF-/- mice. FIR-upregulated PLZF to induce an anti-apoptotic effect in a ß cell line RIN-m5f. FIR also upregulated mitochondrial function and the ratio of NAD+/NADH, and then induced Sirtuin1 (Sirt1) expression. The mitochondria Complex I inhibitor rotenone blocked FIR-induced PLZF and Sirt1. The Sirt1 inhibitor EX527 and Sirt1 siRNA inhibited FIR-induced PLZF and insulin respectively. Sirt1 upregulation also increased CaV1.2 expression and calcium influx that promotes insulin secretion in ß-cells. In summary, FIR-enhanced mitochondrial function prevents ß-cell apoptosis and enhances insulin secretion in DM mice through the Sirt1 pathway.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/radioterapia , Raios Infravermelhos , Células Secretoras de Insulina/patologia , Células Secretoras de Insulina/efeitos da radiação , Sirtuína 1/metabolismo , Sirtuína 1/efeitos da radiação , Animais , Apoptose/genética , Apoptose/efeitos da radiação , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/efeitos da radiação , Teste de Tolerância a Glucose , Secreção de Insulina/efeitos da radiação , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/patologia , Ilhotas Pancreáticas/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Niacinamida , Proteína com Dedos de Zinco da Leucemia Promielocítica/genética , Proteína com Dedos de Zinco da Leucemia Promielocítica/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação , Sirtuína 1/antagonistas & inibidores , Análise de Sobrevida , Regulação para Cima
13.
J Mol Biol ; 432(5): 1551-1578, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-31945378

RESUMO

Genome-wide association studies (GWAS) have identified over 400 signals robustly associated with risk for type 2 diabetes (T2D). At the vast majority of these loci, the lead single nucleotide polymorphisms (SNPs) reside in noncoding regions of the genome, which hampers biological inference and translation of genetic discoveries into disease mechanisms. The study of these T2D risk variants in normoglycemic individuals has revealed that a significant proportion are exerting their disease risk through islet-cell dysfunction. The central role of the islet is also demonstrated by numerous studies, which have shown an enrichment of these signals in islet-specific epigenomic annotations. In recent years the emergence of authentic human beta-cell lines, and advances in genome-editing technologies coupled with improved protocols differentiating human pluripotent stem cells into beta-like cells has opened up new opportunities for T2D disease modeling. Here we review the current understanding on the genetic basis of T2D focusing on approaches, which have facilitated the identification of causal variants and their effector transcripts in human islets. We will present examples of functional studies based on animal and conventional cellular systems and highlight the potential of novel stem cell-based T2D disease models.


Assuntos
Diabetes Mellitus Tipo 2/genética , Ilhotas Pancreáticas/patologia , Animais , Linhagem Celular , Mapeamento Cromossômico , Diabetes Mellitus Tipo 2/metabolismo , Modelos Animais de Doenças , Epigenômica , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla , Humanos , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Ilhotas Pancreáticas/metabolismo , Modelos Animais , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Transcriptoma/genética
14.
FASEB J ; 34(1): 1198-1210, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914655

RESUMO

Early pro-inflammatory signaling in the endocrine pancreas involves activation of NF-κB, which is believed to be important for determining the ultimate fate of ß-cells and hence progression of type 1 diabetes (T1D). Thus, early non-invasive detection of NF-κB in pancreatic islets may serve as a potential strategy for monitoring early changes in pancreatic endocrine cells eventually leading to T1D. We investigated the feasibility of optical imaging of NF-κB transcription factor activation induced by low-dose streptozocin (LD-STZ) treatment in the immunocompetent SKH1 mouse model of early stage diabetes. In this model, we showed that the levels of NF-κB may be visualized and measured by fluorescence intensity of specific near-infrared (NIR) fluorophore-labeled oligodeoxyribonucleotide duplex (ODND) probes. In addition, NF-κB activation following LD-STZ treatment was validated using immunofluorescence and transgenic animals expressing NF-κB inducible imaging reporter. We showed that LD-STZ-treated SKH1 mice had significantly higher (2-3 times, P < .01) specific NIR FI in the nuclei and cytoplasm of islets cells than in non-treated control mice and this finding was corroborated by immunoblotting and electrophoretic mobility shift assays. Finally, using semi-quantitative confocal analysis of non-fixed pancreatic islet microscopy we demonstrated that ODND probes may be used to distinguish between the islets with high levels of NF-κB transcription factor and control islet cells.


Assuntos
Núcleo Celular/metabolismo , Citoplasma/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Ilhotas Pancreáticas/metabolismo , NF-kappa B/metabolismo , Animais , Núcleo Celular/patologia , Citoplasma/patologia , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/patologia , Feminino , Corantes Fluorescentes/farmacologia , Ilhotas Pancreáticas/patologia , Masculino , Camundongos , Camundongos Transgênicos , Microscopia de Fluorescência , NF-kappa B/genética , Oligodesoxirribonucleotídeos/farmacologia
15.
Food Chem Toxicol ; 135: 110894, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31644924

RESUMO

Acrylamide (AA), a food contaminant, caused islet remodeling and increased hepatic glycogen content in male rats, but the effect of AA on glucose homeostasis in female rats remains unclear. In this study, female SD rats were orally treated with 0, 15, or 30 mg/kg·bw AA for 3 weeks. The levels of fasting blood glucose (FBG), blood glucose after oral administration of glucose, plasma insulin and hepatic glycogen were measured. The histology of the pancreas was observed, and the transcription of key genes involved in glucose metabolism and insulin signaling in liver were determined. Compared with the control, exposure to 30 mg/kg·bw of AA significantly increased FBG level, reduced hepatic glycogen content and impaired glucose tolerance. Moreover, damaged islets were observed at 15 and 30 mg/kg·bw AA-exposed groups. In addition, AA exposure significantly promoted gluconeogenesis and glycogenolysis (up-regulation of pc, g6p and gp) and decreased glycolysis (down-regulation of gck and pfk). Alternations in these processes may be associated with decreased plasma insulin levels and inhibited insulin-regulated IRS/PI3K/Akt/Foxo1 signaling transduction under AA exposure. Overall, our findings demonstrated that AA disrupted glucose homeostasis and elevated FBG level in female rats possibly by interfering with glucose metabolism and hampering the physiological effect of insulin.


Assuntos
Acrilamida/efeitos adversos , Glicemia/metabolismo , Homeostase/efeitos dos fármacos , Animais , Feminino , Expressão Gênica/efeitos dos fármacos , Gluconeogênese/genética , Intolerância à Glucose/induzido quimicamente , Glicogenólise/genética , Glicólise/genética , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/patologia , Fígado/efeitos dos fármacos , Glicogênio Hepático/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/genética
16.
Biochimie ; 168: 28-40, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31678111

RESUMO

Chronic obesity imposes an organismal state of low-grade inflammation because the physiological resolution of inflammation is progressively repressed giving rise to cellular senescence and its accompanying Senescence-Associated Secretory Phenotype (SASP), which avoids apoptosis but perpetuates the relay of inflammatory signals from adipose tissue toward the rest of the body. Conversely, resolution of inflammation depends on the integrity of heat shock response (HSR) pathway that leads to the expression of cytoprotective and anti-inflammatory protein chaperones of the 70 kDa family (HSP70). However, chronic exposure to the aforementioned injuring factors leads to SASP, which, in turn, suppresses the HSR. A main metabolic tissue severely jeopardized by obesity-related dysfunctions is the endocrine pancreas, particularly ß-cells of the islets of Langerhans. Because exercise is a powerful inducer of HSR and predicted to alleviate negative health outcomes of obesity, we sought whether obesity influence HSP70 expression in pancreatic islets and other metabolic tissues (adipose tissue and skeletal muscle) of adult B6.129SF2/J mice fed on a high-fat diet (HFD) for 13 weeks since the weaning and whether acute exercise as well as moderate-intensity exercise training (8 weeks) could interfere with this scenario. We showed that acute exercise of moderate intensity protects pancreatic islets against cytokine-induced cell death. In addition, acute exercise challenge time-dependently increased islet HSP70 that peaked at 12 h post-exercise in both trained and untrained mice fed on a control diet, suggesting an adequate HSR to exercise training. Unexpectedly, however, neither exercise training nor acute exercise challenges were able to increase islet HSP70 contents in trained mice submitted to HFD, but only in untrained HFD animals. In parallel, HFD disrupted glycemic status which is accompanied by loss of muscular mass resembling sarcopenic obesity that could not be rescued by exercise training. These results suggest that exercise influences HSR in pancreatic islets but obesity undermines islet, muscle and adipose tissue HSR, which is associated with metabolic abnormalities observed in such tissues.


Assuntos
Tecido Adiposo/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Ilhotas Pancreáticas/metabolismo , Músculo Esquelético/metabolismo , Obesidade/metabolismo , Condicionamento Físico Animal , Animais , Dieta Hiperlipídica , Resposta ao Choque Térmico , Inflamação/metabolismo , Ilhotas Pancreáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos
17.
Eur J Pharmacol ; 866: 172835, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31794708

RESUMO

Diabetes mellitus is characterized by metabolic dysregulation associated with a number of health complications. More than 50% of patients with diabetes mellitus suffer from diabetic polyneuropathy, which involves the presence of peripheral nerve dysfunction symptoms. The aim of this study was to evaluate the potential of a new synthetic arginine-rich exendin-4 (Peptide D) in the treatment of complications caused by diabetes, including peripheral neuropathy, in rats. Diabetes was induced by administering streptozotocin (STZ). Three groups of diabetic rats were treated with Peptide D (0.1, 1, and 10 µg/kg). One group of diabetic rats was treated with Byetta® (1 µg/kg) for 80 days. Neuropathic pain development was assessed by tactile allodynia. STZ-treated rats showed an increased level of tactile allodynia unlike naïve animals. A histological study revealed that the diameter of the sciatic nerve fibers in STZ-treated rats was smaller than that of the naïve animals. An IHC study demonstrated decreased expression of myelin basic protein (MBP) in the sciatic nerve of diabetic rats compared to that in the naïve animals. Peptide D reduced the severity of tactile allodynia. This effect was more pronounced in the Peptide D treated groups than in the group treated with Byetta®. Peptide D and Byetta® treatment resulted in increased MBP expression in the sciatic nerve and increased diameter of myelinated nerve fibers. These findings suggest that poly-arginine peptides are promising agents for the treatment of peripheral polyneuropathies.


Assuntos
Arginina/química , Neuropatias Diabéticas/tratamento farmacológico , Exenatida/química , Exenatida/farmacologia , Animais , Glicemia/metabolismo , Neuropatias Diabéticas/sangue , Neuropatias Diabéticas/patologia , Neuropatias Diabéticas/fisiopatologia , Relação Dose-Resposta a Droga , Exenatida/uso terapêutico , Regulação da Expressão Gênica/efeitos dos fármacos , Hemoglobina A Glicada/metabolismo , Hiperalgesia/complicações , Insulina/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/patologia , Locomoção/efeitos dos fármacos , Masculino , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Wistar , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/patologia
18.
J Ethnopharmacol ; 248: 112356, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31669668

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Tinospora sinensis Lour. (Merr.) belongs to the family Menispermaceae and its stem extract have been used traditionally in broad aspects of therapeutic remedies including debility, dyspepsia, fever, jaundice, ulcer, bronchitis, urinary disease, skin disease, liver disease and diabetes. AIM OF THE STUDY: The aim of the study was to evaluate the protective effects of methanol extract of stem of Tinospora sinensis (METS) on streptozotocin induced pancreatic islet cell injuries of diabetic rats and its correlation to its phytochemical profiles. MATERIALS AND METHODS: A high-performance liquid chromatography technique (HPLC) was used to identify and quantify the major phytochemicals present in the METS. Diabetic rats were administered with METS at a dose of (100, 200 and 400 mg/kg respectively orally) and standard drug Metformin (300 mg/kg) was given orally to group serving positive control. Effect of the METS on glucose homeostasis, oxidative stress, antioxidant status, histopathology of pancreas and also on intracellular reactive oxygen species (ROS), mitochondrial membrane potential, apoptosis, cell cycle of pancreatic islet cells were studied in diabetic rats. RESULTS: The major phytochemicals identified and quantified by HPLC in the extract were berberine, caffeic acid, myricetin and ferulic acid. This result showed that methanol extract exhibited good antioxidant effect. The methanol extract of the plant prevented the diabetogenic effect of STZ and significantly lowered the fasting blood glucose level, glycated haemoglobin and increased insulin and C-peptide level in treated rats. METS reduced apoptosis of STZ treated islet cells by significantly decreasing pro-inflammatory cytokines (TNFα, IL6), intracellular ROS generation, lipid peroxidation, nitric oxide (NO) production and increasing mitochondrial membrane potential and sub-G0 peak area, enzymatic and nonenzymatic antioxidants. CONCLUSION: The results revealed that the methanol extract of the stem of the plant possesses protective effects against diabetes and associated complications.


Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Diabetes Mellitus Experimental/prevenção & controle , Hipoglicemiantes/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Extratos Vegetais/farmacologia , Tinospora , Animais , Anti-Inflamatórios/isolamento & purificação , Antioxidantes/isolamento & purificação , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Hemoglobina A Glicada/metabolismo , Hipoglicemiantes/isolamento & purificação , Mediadores da Inflamação/metabolismo , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Lipídeos/sangue , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Estreptozocina , Tinospora/química
19.
Nat Med ; 25(12): 1865-1872, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31792456

RESUMO

Viruses are implicated in autoimmune destruction of pancreatic islet ß cells, which results in insulin deficiency and type 1 diabetes (T1D)1-4. Certain enteroviruses can infect ß cells in vitro5, have been detected in the pancreatic islets of patients with T1D6 and have shown an association with T1D in meta-analyses4. However, establishing consistency in findings across studies has proven difficult. Obstacles to convincingly linking RNA viruses to islet autoimmunity may be attributed to rapid viral mutation rates, the cyclical periodicity of viruses7 and the selection of variants with altered pathogenicity and ability to spread in populations. ß cells strongly express cell-surface coxsackie and adenovirus receptor (CXADR) genes, which can facilitate enterovirus infection8. Studies of human pancreata and cultured islets have shown significant variation in enteroviral virulence to ß cells between serotypes and within the same serotype9,10. In this large-scale study of known eukaryotic DNA and RNA viruses in stools from children, we evaluated fecally shed viruses in relation to islet autoimmunity and T1D. This study showed that prolonged enterovirus B rather than independent, short-duration enterovirus B infections may be involved in the development of islet autoimmunity, but not T1D, in some young children. Furthermore, we found that fewer early-life human mastadenovirus C infections, as well as CXADR rs6517774, independently correlated with islet autoimmunity.


Assuntos
Autoimunidade/imunologia , Diabetes Mellitus Tipo 1/virologia , Enterovirus/isolamento & purificação , RNA Viral/isolamento & purificação , Adolescente , Autoimunidade/genética , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/patologia , Enterovirus/imunologia , Enterovirus/patogenicidade , Fezes/virologia , Feminino , Humanos , Lactente , Insulina/metabolismo , Células Secretoras de Insulina/imunologia , Células Secretoras de Insulina/virologia , Ilhotas Pancreáticas/imunologia , Ilhotas Pancreáticas/patologia , Ilhotas Pancreáticas/virologia , Masculino , Pâncreas/imunologia , Pâncreas/patologia , Pâncreas/virologia
20.
Mol Med Rep ; 20(6): 5152-5162, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31702811

RESUMO

Insulin resistance (IR) is the impaired insulin response that causes decreased glucose tolerance. Electrical stimulation (ES) can improve insulin sensitivity in the skeletal muscle. However, the underlying molecular mechanisms remain to be elucidated. In the present study, the effect of ES and diet therapy on IR and the role of the mammalian target of rapamycin (mTOR) pathway in the improvement of IR by ES were investigated. A total of 70 Sprague­Dawley male rats were divided into five groups: Normal (n=10), IR control (n=15), diet (n=15), ES (n=15) and ES + diet (n=15) groups. An IR rat model was established by high­fat and high­carbohydrate diet for 5 weeks and confirmed by measurement of fasting plasma glucose (FPG), insulin, insulin sensitivity index (ISI) and IR index. ES on the Zusanli (ST36), Sanyinjiao (SP 6) and Weiwanxiashu (EX­B3) acupoints and the low­fat and low­carbohydrate diet demonstrated protective effects. The body weight, concentrations of FPG, insulin, triglycerides (TG), free fatty acids (FFA) and total cholesterol (TC) of the rats were detected. Pathologic changes in the liver and pancreatic tissues were assessed. Western blotting and immunohistochemistry were performed to determine the role of PI3K/Akt/mTOR signaling. Results demonstrated that ES and diet therapy significantly increased ISI and reduced FPG, IR index, FFA, TG, TC and weight. Inflammatory cell infiltration in the liver and pancreatic tissues was ameliorated and lipid droplets and cavitation in hepatocyte were decreased after ES and diet therapy. The administration of ES and diet therapy also enhanced glucose transport by the upregulation of glucose transporter 4 and accelerated glycogen synthesis through the suppression of glycogen synthase kinase 3α/ß via PI3K/Akt/mTOR signaling. Hence, the present results demonstrated that ES combined with diet therapy improved IR through PI3K/Akt/mTOR signaling. The proposed therapy was superior to the method of diet alone.


Assuntos
Dietoterapia/métodos , Estimulação Elétrica/métodos , Resistência à Insulina/fisiologia , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Animais , Peso Corporal , Dieta com Restrição de Carboidratos , Dieta com Restrição de Gorduras , Glicogênio/biossíntese , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Fígado/metabolismo , Fígado/patologia , Masculino , Músculos/metabolismo , Músculos/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Ratos , Ratos Sprague-Dawley , Triglicerídeos/metabolismo
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