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1.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34360954

RESUMO

Ca2+-dependent gene regulation controls several functions to determine the fate of the cells. Proteins of the nuclear factor of activated T-cells (NFAT) family are Ca2+ sensitive transcription factors that control the cell growth, proliferation and insulin secretion in ß-cells. Translocation of NFAT proteins to the nucleus occurs in a sequence of events that starts with activating calmodulin-dependent phosphatase calcineurin in a Ca2+-dependent manner, which dephosphorylates the NFAT proteins and leads to their translocation to the nucleus. Here, we examined the role of IP3-generating agonists and near-UV light in the induction of NFATc3 migration to the nucleus in the pancreatic ß-cell line INS-1. Our results show that IP3 generation yields cytosolic Ca2+ rise and NFATc3 translocation. Moreover, near-UV light exposure generates reactive oxygen species (ROS), resulting in cytosolic Ca2+ spiking via the L-type Ca2+ channel and triggers NFATc3 translocation to the nucleus. Using the mitochondria as a Ca2+ buffering tool, we showed that ROS-induced cytosolic Ca2+ spiking, not the ROS themselves, was the triggering mechanism of nuclear import of NFATc3. Collectively, this study reveals the mechanism of near-UV light induced NFATc3 migration.


Assuntos
Sinalização do Cálcio , Fatores de Transcrição NFATC/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Raios Ultravioleta , Animais , Canais de Cálcio Tipo L/metabolismo , Linhagem Celular Tumoral , Inositol 1,4,5-Trifosfato/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efeitos da radiação , Ratos
2.
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
3.
Cell Death Dis ; 10(6): 457, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31186419

RESUMO

In type 2 diabetes mellitus (T2DM), the overload of glucose and lipids can promote oxidative stress and inflammatory responses and contribute to the failure of beta cells. However, therapies that can modulate the function of beta cells and thus prevent their failure have not been well explored. In this study, beta cell injury model was established with palmitic acid (PA) to simulate the lipotoxicity (high-fat diet) found in T2DM. Sonodynamic therapy (SDT), a novel physicochemical treatment, was applied to treat injured beta cells. We found that SDT had specific effects on mitochondria and induced transient large amount of mitochondrial reactive oxygen species (ROS) production in beta cells. SDT also improved the morphology and function of abnormal mitochondria, inhibited inflammatory response and reduced beta cell dysfunction. The improvement of mitochondria was mediated by PINK1/Parkin-dependent mitophagy. Additionally, SDT rescued the transcription of PINK1 mRNA which was blocked by PA treatment, thus providing abundant PINK1 for mitophagy. Moreover, SDT also increased insulin secretion from beta cells. The protective effects of SDT were abrogated when mitophagy was inhibited by cyclosporin A (CsA). In summary, SDT potently inhibits lipotoxicity-induced beta cell failure via PINK1/Parkin-dependent mitophagy, providing theoretical guidance for T2DM treatment in aspects of islet protection.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Células Secretoras de Insulina/metabolismo , Mitocôndrias/efeitos da radiação , Mitofagia/efeitos da radiação , Proteínas Quinases/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ondas Ultrassônicas , Animais , Proteínas de Transporte/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Sobrevivência Celular/efeitos da radiação , Diabetes Mellitus Tipo 2/metabolismo , Inflamação/metabolismo , Inflamação/radioterapia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos da radiação , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Mitofagia/efeitos dos fármacos , Mitofagia/genética , Ácido Palmítico/farmacologia , Ácido Palmítico/toxicidade , Proteínas Quinases/genética , Protoporfirinas/metabolismo , Ratos , Espécies Reativas de Oxigênio/metabolismo , Receptores de GABA-A/metabolismo , Ubiquitina-Proteína Ligases/genética
4.
Nucleic Acids Res ; 47(8): 4039-4053, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-30722038

RESUMO

FBXW7, a classic tumor suppressor, is a substrate recognition subunit of the Skp1-cullin-F-box (SCF) ubiquitin ligase that targets oncoproteins for ubiquitination and degradation. We recently found that FBXW7 is recruited to DNA damage sites to facilitate nonhomologous end-joining (NHEJ). The detailed underlying molecular mechanism, however, remains elusive. Here we report that the WD40 domain of FBXW7, which is responsible for substrate binding and frequently mutated in human cancers, binds to poly(ADP-ribose) (PAR) immediately following DNA damage and mediates rapid recruitment of FBXW7 to DNA damage sites, whereas ATM-mediated FBXW7 phosphorylation promotes its retention at DNA damage sites. Cancer-associated arginine mutations in the WD40 domain (R465H, R479Q and R505C) abolish both FBXW7 interaction with PAR and recruitment to DNA damage sites, causing inhibition of XRCC4 polyubiquitination and NHEJ. Furthermore, inhibition or silencing of poly(ADP-ribose) polymerase 1 (PARP1) inhibits PAR-mediated recruitment of FBXW7 to the DNA damage sites. Taken together, our study demonstrates that the WD40 domain of FBXW7 is a novel PAR-binding motif that facilitates early recruitment of FBXW7 to DNA damage sites for subsequent NHEJ repair. Abrogation of this ability seen in cancer-derived FBXW7 mutations provides a molecular mechanism for defective DNA repair, eventually leading to genome instability.


Assuntos
Reparo do DNA por Junção de Extremidades , Proteína 7 com Repetições F-Box-WD/genética , Poli(ADP-Ribose) Polimerase-1/genética , Poli Adenosina Difosfato Ribose/metabolismo , Fator de Células-Tronco/genética , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sítios de Ligação , Linhagem Celular , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos da radiação , Dano ao DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteína 7 com Repetições F-Box-WD/química , Proteína 7 com Repetições F-Box-WD/metabolismo , Fibroblastos/metabolismo , Fibroblastos/efeitos da radiação , Fibroblastos/ultraestrutura , Raios gama , Células HCT116 , Humanos , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efeitos da radiação , Células Secretoras de Insulina/ultraestrutura , Modelos Moleculares , Mutação , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli Adenosina Difosfato Ribose/química , Ligação Proteica , Domínios Proteicos , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Fator de Células-Tronco/metabolismo , Ubiquitinação/efeitos da radiação
5.
Mol Ther ; 26(11): 2542-2552, 2018 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-30415658

RESUMO

CD19 chimeric antigen receptors (CARs) have demonstrated great efficacy against a range of B cell malignancies. However, antigen escape and, more generally, heterogeneous antigen expression pose a challenge to applying CAR therapy to a wide range of cancers. We find that low-dose radiation sensitizes tumor cells to immune rejection by locally activated CAR T cells. In a model of pancreatic adenocarcinoma heterogeneously expressing sialyl Lewis-A (sLeA), we show that not only sLeA+ but also sLeA- tumor cells exposed to low-dose radiation become susceptible to CAR therapy, reducing antigen-negative tumor relapse. RNA sequencing analysis of low-dose radiation-exposed tumors reveals the transcriptional signature of cells highly sensitive to TRAIL-mediated death. We find that sLeA-targeted CAR T cells produce TRAIL upon engaging sLeA+ tumor cells, and eliminate sLeA- tumor cells previously exposed to systemic or local low-dose radiation in a TRAIL-dependent manner. These findings enhance the prospects for successfully applying CAR therapy to heterogeneous solid tumors. Local radiation is integral to many tumors' standard of care and can be easily implemented as a CAR conditioning regimen.


Assuntos
Antígenos CD19/uso terapêutico , Imunoterapia Adotiva , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/radioterapia , Ligante Indutor de Apoptose Relacionado a TNF/genética , Animais , Antígenos CD19/imunologia , Antígenos de Neoplasias/química , Antígenos de Neoplasias/imunologia , Antígenos de Neoplasias/efeitos da radiação , Antígeno CA-19-9 , Terapia Combinada , Modelos Animais de Doenças , Humanos , Células Secretoras de Insulina/imunologia , Células Secretoras de Insulina/efeitos da radiação , Camundongos , Oligossacarídeos/química , Oligossacarídeos/imunologia , Oligossacarídeos/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Radiação , Doses de Radiação , Receptores de Antígenos Quiméricos/imunologia , Receptores de Antígenos Quiméricos/uso terapêutico , Análise de Sequência de RNA , Ligante Indutor de Apoptose Relacionado a TNF/imunologia
6.
Sci Rep ; 7(1): 9357, 2017 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-28839233

RESUMO

Pancreatic ß-cell insulin production is orchestrated by a complex circuitry involving intracellular elements including cyclic AMP (cAMP). Tackling aberrations in glucose-stimulated insulin release such as in diabetes with pharmacological agents, which boost the secretory capacity of ß-cells, is linked to adverse side effects. We hypothesized that a photoactivatable adenylyl cyclase (PAC) can be employed to modulate cAMP in ß-cells with light thereby enhancing insulin secretion. To that end, the PAC gene from Beggiatoa (bPAC) was delivered to ß-cells. A cAMP increase was noted within 5 minutes of photostimulation and a significant drop at 12 minutes post-illumination. The concomitant augmented insulin secretion was comparable to that from ß-cells treated with secretagogues. Greater insulin release was also observed over repeated cycles of photoinduction without adverse effects on viability and proliferation. Furthermore, the expression and activation of bPAC increased cAMP and insulin secretion in murine islets and in ß-cell pseudoislets, which displayed a more pronounced light-triggered hormone secretion compared to that of ß-cell monolayers. Calcium channel blocking curtailed the enhanced insulin response due to bPAC activity. This optogenetic system with modulation of cAMP and insulin release can be employed for the study of ß-cell function and for enabling new therapeutic modalities for diabetes.


Assuntos
Secreção de Insulina/efeitos da radiação , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efeitos da radiação , Luz , Optogenética , Adenilil Ciclases/genética , Adenilil Ciclases/metabolismo , Animais , Linhagem Celular , AMP Cíclico/metabolismo , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/efeitos da radiação , Camundongos , Optogenética/métodos
7.
Ultrasound Med Biol ; 43(6): 1210-1222, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28347531

RESUMO

Type 2 diabetes mellitus is a complex metabolic disease that has reached epidemic proportions in the United States and around the world. This disease is characterized by loss of insulin secretion and, eventually, destruction of insulin-producing pancreatic beta cells. Controlling type 2 diabetes is often difficult as pharmacological management routinely requires complex therapy with multiple medications, and loses its effectiveness over time. The objective of this study was to explore the effectiveness of a novel, non-pharmacological approach that uses the application of ultrasound energy to augment insulin release from rat INS 832/13 beta cells. The cells were exposed to unfocused ultrasound for 5 min at a peak intensity of 1 W/cm2 and frequencies of 400 kHz, 600 kHz, 800 kHz and 1 MHz. Insulin release was measured with enzyme-linked immunosorbent assay and cell viability was assessed via the trypan blue dye exclusion test. A marked release (approximately 150 ng/106 cells, p < 0.05) of insulin was observed when beta cells were exposed to ultrasound at 400 and 600 kHz as compared with their initial control values; however, this release was accompanied by a substantial loss in cell viability. Ultrasound application at frequencies of 800 kHz resulted in 24 ng/106 cells released insulin (p < 0.05) as compared with its unstimulated base level, while retaining cell viability. Insulin release from beta cells caused by application of 800-kHz ultrasound was comparable to that reported by the secretagogue glucose, thus operating within physiological secretory capacity of these cells. Ultrasound has potential as a novel and alternative method to current approaches aimed at correcting secretory deficiencies in patients with type 2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efeitos da radiação , Insulina/biossíntese , Sonicação/métodos , Terapia por Ultrassom/métodos , Animais , Linhagem Celular , Preparações de Ação Retardada/administração & dosagem , Diabetes Mellitus Tipo 2/diagnóstico por imagem , Ondas de Choque de Alta Energia , Hipoglicemiantes/administração & dosagem , Ratos , Resultado do Tratamento
8.
Sci Rep ; 7: 39800, 2017 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-28067253

RESUMO

Radiolabeled exendin is used for non-invasive quantification of beta cells in the islets of Langerhans in vivo. High accumulation of radiolabeled exendin in the islets raised concerns about possible radiation-induced damage to these islets in man. In this work, islet absorbed doses resulting from exendin-imaging were calculated by combining whole organ dosimetry with small scale dosimetry for the islets. Our model contains the tissues with high accumulation of radiolabeled exendin: kidneys, pancreas and islets. As input for the model, data from a clinical study (radiolabeled exendin distribution in the human body) and from a preclinical study with Biobreeding Diabetes Prone (BBDP) rats (islet-to-exocrine uptake ratio, beta cell mass) were used. We simulated 111In-exendin and 68Ga-exendin absorbed doses in patients with differences in gender, islet size, beta cell mass and radiopharmaceutical uptake in the kidneys. In all simulated cases the islet absorbed dose was small, maximum 1.38 mGy for 68Ga and 66.0 mGy for 111In. The two sources mainly contributing to the islet absorbed dose are the kidneys (33-61%) and the islet self-dose (7.5-57%). In conclusion, all islet absorbed doses are low (<70 mGy), so even repeated imaging will hardly increase the risk on diabetes.


Assuntos
Células Secretoras de Insulina/patologia , Ilhotas Pancreáticas/patologia , Rim/metabolismo , Lesões por Radiação/diagnóstico , Radiometria/métodos , Adulto , Animais , Contagem de Células , Diabetes Mellitus/etiologia , Diabetes Mellitus/genética , Modelos Animais de Doenças , Feminino , Radioisótopos de Gálio/química , Radioisótopos de Gálio/metabolismo , Humanos , Radioisótopos de Índio/química , Radioisótopos de Índio/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efeitos da radiação , Peptídeos e Proteínas de Sinalização Intercelular , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/efeitos da radiação , Rim/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Peptídeos/química , Peptídeos/metabolismo , Radiação , Doses de Radiação , Ratos , Ratos Mutantes , Adulto Jovem
9.
Am J Physiol Endocrinol Metab ; 310(1): E41-50, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26530153

RESUMO

The intestinal L cell is the principal source of glucagon-like peptide-1 (GLP-1), a major determinant of insulin release. Because GLP-1 secretion is regulated in a circadian manner in rodents, we investigated whether the activity of the human L cell is also time sensitive. Rhythmic fluctuations in the mRNA levels of canonical clock genes were found in the human NCI-H716 L cell model, which also showed a time-dependent pattern in their response to well-established secretagogues. A diurnal variation in GLP-1 responses to identical meals (850 kcal), served 12 h apart in the normal dark (2300) and light (1100) periods, was also observed in male volunteers maintained under standard sleep and light conditions. These findings suggest the existence of a daily pattern of activity in the human L cell. Moreover, we separately tested the short-term effects of sleep deprivation and nocturnal light exposure on basal and postprandial GLP-1, insulin, and glucose levels in the same volunteers. Sleep deprivation with nocturnal light exposure disrupted the melatonin and cortisol profiles and increased insulin resistance. Moreover, it also induced profound derangements in GLP-1 and insulin responses such that postprandial GLP-1 and insulin levels were markedly elevated and the normal variation in GLP-1 responses was abrogated. These alterations were not observed in sleep-deprived participants maintained under dark conditions, indicating a direct effect of light on the mechanisms that regulate glucose homeostasis. Accordingly, the metabolic abnormalities known to occur in shift workers may be related to the effects of irregular light-dark cycles on these glucoregulatory pathways.


Assuntos
Peptídeo 1 Semelhante ao Glucagon/metabolismo , Células Secretoras de Glucagon/metabolismo , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Privação do Sono/metabolismo , Adolescente , Adulto , Proteínas CLOCK/genética , Células Cultivadas , Ritmo Circadiano/fisiologia , Células Secretoras de Glucagon/efeitos da radiação , Voluntários Saudáveis , Humanos , Secreção de Insulina , Células Secretoras de Insulina/efeitos da radiação , Luz , Masculino , Redes e Vias Metabólicas/genética , Redes e Vias Metabólicas/efeitos da radiação , Fatores de Tempo , Adulto Jovem
10.
Nat Commun ; 6: 10056, 2015 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-26686736

RESUMO

Photoactivation of caged biomolecules has become a powerful approach to study cellular signalling events. Here we report a method for anchoring and uncaging biomolecules exclusively at the outer leaflet of the plasma membrane by employing a photocleavable, sulfonated coumarin derivative. The novel caging group allows quantifying the reaction progress and efficiency of uncaging reactions in a live-cell microscopy setup, thereby greatly improving the control of uncaging experiments. We synthesized arachidonic acid derivatives bearing the new negatively charged or a neutral, membrane-permeant coumarin caging group to locally induce signalling either at the plasma membrane or on internal membranes in ß-cells and brain slices derived from C57B1/6 mice. Uncaging at the plasma membrane triggers a strong enhancement of calcium oscillations in ß-cells and a pronounced potentiation of synaptic transmission while uncaging inside cells blocks calcium oscillations in ß-cells and causes a more transient effect on neuronal transmission, respectively. The precise subcellular site of arachidonic acid release is therefore crucial for signalling outcome in two independent systems.


Assuntos
Ácido Araquidônico/metabolismo , Membrana Celular/metabolismo , Animais , Ácido Araquidônico/química , Cálcio/metabolismo , Sinalização do Cálcio/efeitos da radiação , Membrana Celular/efeitos da radiação , Cumarínicos/química , Cumarínicos/metabolismo , Células HeLa , Humanos , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efeitos da radiação , Luz , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Neurônios/efeitos da radiação
11.
Gene Ther ; 22(7): 553-9, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25809465

RESUMO

The present study assessed the ability of optogenetics techniques to provide a better understanding of the control of insulin secretion, particularly regarding pancreatic ß-cell function in homeostasis and pathological conditions such as diabetes mellitus (DM). We used optogenetics to investigate whether insulin secretion and blood glucose homeostasis could be controlled by regulating intracellular calcium ion concentrations ([Ca(2+)]i) in a mouse pancreatic ß-cell line (MIN6) transfected with the optogenetic protein channelrhodopsin-2 (ChR2). The ChR2-transfected MIN6 (ChR2-MIN6) cells secreted insulin following irradiation with a laser (470 nm). The increase in [Ca(2+)]i was accompanied by elevated levels of messenger RNAs that encode calcium/calmodulin-dependent protein kinase II delta and adenylate cyclase 1. ChR2-MIN6 cells suspended in matrigel were inoculated into streptozotocin-induced diabetic mice that were then subjected to a glucose tolerance test. Laser irradiation of these mice caused a significant decrease in blood glucose, and the irradiated implanted cells expressed insulin. These findings demonstrate the power of optogenetics to precisely and efficiently controlled insulin secretion by pancreatic ß-cells 'on demand', in contrast to techniques using growth factors or chemical inducers. Optogenetic technology shows great promise for understanding the mechanisms of glucose homeostasis and for developing treatments for metabolic diseases such as DM.


Assuntos
Diabetes Mellitus Experimental/radioterapia , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Terapia com Luz de Baixa Intensidade , Optogenética , Adenilil Ciclases/metabolismo , Animais , Glicemia/metabolismo , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Células Cultivadas , Channelrhodopsins , Diabetes Mellitus Experimental/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/efeitos da radiação , Terapia com Luz de Baixa Intensidade/métodos , Camundongos , Estreptozocina
12.
Chem Commun (Camb) ; 51(27): 6018-21, 2015 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-25744824
13.
J Cell Biochem ; 116(8): 1741-54, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25736682

RESUMO

Promotion of insulin-secreting ß-cell regeneration in patients with diabetes is a promising approach for diabetes therapy, which can contribute to rescue the uncontrolled hyperglycemia. Low-power laser irradiation (LPLI) has been demonstrated to regulate multiple physiological processes both in vitro and in vivo through activation of various signaling pathways. In the present study, we showed that LPLI promoted ß-cell replication and cell cycle progression through activation of Akt1/GSK3ß isoform-specific signaling axis. Inhibition of PI3-K/Akt or GSK3 with specific inhibitors dramatically reduced or increased LPLI-induced ß-cell replication, revealing Akt/GSK3 signaling axis was involved in ß-cell replication and survival upon LPLI treatment. Furthermore, the results of shRNA-mediated knock down of Akt/GSK3 isoforms revealed that Akt1/GSK3ß isoform-specific signaling axis regulated ß-cell replication and survival in response to LPLI, but not Akt2/GSK3α. The mechanism by which LPLI promoted ß-cell replication through Akt1/GSK3ß signaling axis involved activation of ß-catenin and down-regulation of p21. Taken together, these observations suggest that Akt1/GSK3ß isoform signaling axis play a key role in ß-cell replication and survival induced by LPLI. Moreover, our findings suggest that activation of Akt1/GSK3ß isoform signaling axis by LPLI may provide guidance in practical applications for ß-cell regenerative therapies.


Assuntos
Quinase 3 da Glicogênio Sintase/metabolismo , Células Secretoras de Insulina/fisiologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regeneração/efeitos da radiação , Animais , Ciclo Celular/efeitos da radiação , Proliferação de Células/efeitos da radiação , Quinase 3 da Glicogênio Sintase/genética , Glicogênio Sintase Quinase 3 beta , Células Secretoras de Insulina/efeitos da radiação , Isoenzimas/genética , Isoenzimas/metabolismo , Terapia com Luz de Baixa Intensidade , Masculino , Proteínas Proto-Oncogênicas c-akt/genética , Ratos , Transdução de Sinais/efeitos da radiação
14.
Nat Commun ; 5: 5116, 2014 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-25311795

RESUMO

Sulfonylureas are widely prescribed for the treatment of type 2 diabetes mellitus (T2DM). Through their actions on ATP-sensitive potassium (KATP) channels, sulfonylureas boost insulin release from the pancreatic beta cell mass to restore glucose homeostasis. A limitation of these compounds is the elevated risk of developing hypoglycemia and cardiovascular disease, both potentially fatal complications. Here, we describe the design and development of a photoswitchable sulfonylurea, JB253, which reversibly and repeatedly blocks KATP channel activity following exposure to violet-blue light. Using in situ imaging and hormone assays, we further show that JB253 bestows light sensitivity upon rodent and human pancreatic beta cell function. Thus, JB253 enables the optical control of insulin release and may offer a valuable research tool for the interrogation of KATP channel function in health and T2DM.


Assuntos
Hipoglicemiantes/farmacologia , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Compostos de Sulfonilureia/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/efeitos da radiação , Linhagem Celular , Feminino , Humanos , Hipoglicemiantes/síntese química , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos da radiação , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/efeitos da radiação , Canais KATP/metabolismo , Luz , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Compostos de Sulfonilureia/síntese química
15.
Environ Res ; 133: 253-9, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24981823

RESUMO

BACKGROUND: Ultraviolet irradiation by sun exposure has been associated with both harms and benefits to metabolic health. OBJECTIVE: The objective of this study was to determine whether unprotected daily sun exposure is associated with the prevalence of diabetes and explore the underlying mechanism. METHODS: We analyzed the Korean National Health and Nutrition Survey V from 2010 to 2011. Participants 19-60 years of age were asked about the average amount of time they had been exposed to direct sunlight per day since the age of 19. We categorized participants into three groups with different levels of lifetime daily sun exposure and explored the association of sun exposure with the prevalence of diabetes. RESULTS: The risk of diabetes was higher in subjects with more than 5h of unprotected sun exposure per day, with an odds ratio of 2.39 (95% CI 1.75-3.25), compared to those with less than 2h of sun exposure, and the association remained significant after adjusting for diabetes risk factors. Long-term sun exposure was associated with increased central obesity and the possibility of an increase in visceral adiposity, especially among women, and with decrease in beta cell function and peripheral adiposity or percent body fat in men. CONCLUSIONS: Our study provides a cutoff for upper limit of sun exposure and suggests unprotected daily sun exposure for more than 5h should be avoided to prevent diabetes. Increased central adiposity and decreased beta cell function were observed in women and men, respectively, who had long-term unprotected daily sun exposure.


Assuntos
Adiposidade , Diabetes Mellitus/epidemiologia , Inquéritos Nutricionais , Obesidade/epidemiologia , Luz Solar/efeitos adversos , Adulto , Diabetes Mellitus/etiologia , Diabetes Mellitus/patologia , Feminino , Humanos , Resistência à Insulina/efeitos da radiação , Células Secretoras de Insulina/patologia , Células Secretoras de Insulina/efeitos da radiação , Masculino , Pessoa de Meia-Idade , Obesidade/etiologia , Obesidade/patologia , Prevalência , República da Coreia/epidemiologia , Caracteres Sexuais , Adulto Jovem
16.
Int J Occup Med Environ Health ; 26(2): 235-41, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23771861

RESUMO

OBJECTIVE: Extensive use of mobile phones has been accompanied by a common public debate about possible adverse effects on human health. No study has been published so far to establish any association between the fastest growing innovation of mobile phone and fasting blood glucose. The aim was to determine the effects of exposure to electromagnetic field radiation generated by mobile phones on fasting blood glucose in Wistar Albino rats. MATERIALS AND METHODS: 40 Male Albino rats (Wistar Strain) were divided into 5 equally numerous groups. Group A served as the control one, group B received mobile phone radiation for less than 15 min/day, group C: 15-30 min/day, group D: 31-45 min/day, and group E: 46-60 min/day for a total period of 3 months. Fasting blood glucose was determined by using Spectrophotometer and serum insulin by Enzyme-linked Immunosorbent Assay (ELISA). The Homeostatic Model (HOMA-B) was applied for the assessment of ß-cell function and (HOMA-IR) for resistance to insulin. RESULTS: Wister Albino rats exposed to mobile phone radiation for longer than 15 min a day for a total period of 3 months had significantly higher fasting blood glucose (p < 0.015) and serum insulin (p < 0.01) compared to the control group. HOMA-IR for insulin resistance was significantly increased (p < 0.003) in the groups that were exposed for 15-30 and 46-60 min/day compared to the control rats. CONCLUSION: The results of the present study show an association between long-term exposure to activated mobile phones and increase in fasting blood glucose and serum insulin in Albino rats.


Assuntos
Glicemia/efeitos da radiação , Telefone Celular , Campos Eletromagnéticos , Exposição Ambiental , Resistência à Insulina/efeitos da radiação , Animais , Homeostase/efeitos da radiação , Células Secretoras de Insulina/efeitos da radiação , Masculino , Ratos
17.
Biomaterials ; 32(36): 9685-95, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21924490

RESUMO

Hydrogels provide three-dimensional frameworks with tissue-like elasticity and high permeability for culturing therapeutically relevant cells or tissues. While recent research efforts have created diverse macromer chemistry to form hydrogels, the mechanisms of hydrogel polymerization for in situ cell encapsulation remain limited. Hydrogels prepared from chain-growth photopolymerization of poly(ethylene glycol) diacrylate (PEGDA) are commonly used to encapsulate cells. However, free radical associated cell damage poses significant limitation for this gel platform. More recently, PEG hydrogels formed by thiol-ene photo-click chemistry have been developed for cell encapsulation. While both chain-growth and step-growth photopolymerizations offer spatial-temporal control over polymerization kinetics, step-growth thiol-ene hydrogels offer more diverse and preferential properties. Here, we report the superior properties of step-growth thiol-ene click hydrogels, including cytocompatibility of the reactions, improved hydrogel physical properties, and the ability for 3D culture of pancreatic ß-cells. Cells encapsulated in thiol-ene hydrogels formed spherical clusters naturally and were retrieved via rapid chymotrypsin-mediated gel erosion. The recovered cell spheroids released insulin in response to glucose treatment, demonstrating the cytocompatibility of thiol-ene hydrogels and the enzymatic mechanism of cell spheroids recovery. Thiol-ene click reactions provide an attractive means to fabricate PEG hydrogels with superior gel properties for in situ cell encapsulation, as well as to generate and recover 3D cellular structures for regenerative medicine applications.


Assuntos
Química Click/métodos , Hidrogéis/síntese química , Hidrogéis/farmacologia , Células Secretoras de Insulina/citologia , Luz , Esferoides Celulares/citologia , Compostos de Sulfidrila/síntese química , Animais , Fenômenos Biofísicos/efeitos dos fármacos , Fenômenos Biofísicos/efeitos da radiação , Contagem de Células , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Células Imobilizadas/citologia , Células Imobilizadas/efeitos dos fármacos , Células Imobilizadas/efeitos da radiação , Quimotripsina/metabolismo , Reagentes de Ligações Cruzadas/farmacologia , Módulo de Elasticidade/efeitos dos fármacos , Módulo de Elasticidade/efeitos da radiação , Hidrogéis/química , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos da radiação , Camundongos , Polietilenoglicóis/química , Polimerização/efeitos dos fármacos , Polimerização/efeitos da radiação , Esferoides Celulares/efeitos dos fármacos , Esferoides Celulares/efeitos da radiação , Compostos de Sulfidrila/química
18.
Diabetologia ; 52(1): 115-24, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18946656

RESUMO

AIMS/HYPOTHESIS: Recent studies have shown that bone marrow transplantation reduces hyperglycaemia in a mouse model of diabetes induced by streptozotocin. However, the essential factors for the improvement of hyperglycaemia by bone marrow transplantation have not been fully elucidated. The aim of this study was to search for such factors. METHODS: We investigated the effect of irradiation to whole body, to abdomen alone or to whole body excluding abdomen, followed by infusion or no infusion of bone marrow cells. We also investigated the effect of bone marrow transplantation on beta cell-specific vascular endothelial growth factor-A gene (Vegfa) knockout mice. RESULTS: Bone marrow transplantation improved streptozotocin-induced hyperglycaemia and partially restored islet mass. This change was associated with increased islet vascularisation. Among the other methods investigated, low-dose irradiation of the whole body without infusion of bone marrow cells also improved blood glucose level. In streptozotocin-treated beta cell-specific Vegfa knockout mice, which exhibit impaired islet vascularisation, bone marrow transplantation neither improved hyperglycaemia, relative beta cell mass nor islet vascularisation. CONCLUSION/INTERPRETATION: Our results indicate that whole body irradiation is essential and sufficient for restoration of beta cell mass after streptozotocin treatment independent of infusion of bone marrow cells. Vascular endothelial growth factor-A produced in beta cells is also essential for this phenomenon.


Assuntos
Transplante de Medula Óssea , Diabetes Mellitus Experimental/cirurgia , Células Secretoras de Insulina/citologia , Fator A de Crescimento do Endotélio Vascular/farmacologia , Irradiação Corporal Total , Animais , Modelos Animais de Doenças , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/fisiologia , Teste de Tolerância a Glucose , Hiperglicemia/prevenção & controle , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transplante Isogênico
19.
Bioelectromagnetics ; 30(1): 1-8, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18521845

RESUMO

The magnetic flux density of MRI for clinical diagnosis has been steadily increasing. However, there remains very little biological data regarding the effect of strong static magnetic fields (SMFs) on human health. To evaluate the effects of strong SMFs on biological systems, we cultured insulin-secreting cells under exposure to sham and SMF conditions (3-10 T of magnetic flux density, and 0-41.7 T/m of magnetic field gradient) for 0.5 or 1 h, and analyzed insulin secretion, mRNA expression, glucose-stimulated insulin secretion, insulin content, cell proliferation and cell number. Exposure to SMF with a high magnetic field gradient for 1 h significantly increased insulin secretion and insulin 1 mRNA expression. Exposure to SMF with a high magnetic flux density for 0.5 h significantly enhanced responsiveness to glucose stimulation. Exposure to SMF did not affect the insulin content, cell proliferation or cell number. Our results suggested that MRI systems with a higher magnetic flux density might not cause cell proliferative or functional damages on insulin-secreting cells, and that SMF with a high magnetic field gradient might be used clinically after thorough in vivo investigations are conducted.


Assuntos
Células Secretoras de Insulina/fisiologia , Células Secretoras de Insulina/efeitos da radiação , Insulina/metabolismo , Imageamento por Ressonância Magnética , Animais , Linhagem Celular , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Relação Dose-Resposta à Radiação , Campos Eletromagnéticos , Secreção de Insulina , Células Secretoras de Insulina/citologia , Doses de Radiação , Ratos
20.
Bioelectromagnetics ; 29(2): 118-24, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17929267

RESUMO

To evaluate the effects of extremely low frequency magnetic field (ELFMF) on beta-cell survival and function, we cultured a hamster-derived insulin-secreting cell line (HIT-T15), which exhibits responsiveness to glucose in a semi-physiological range, under exposure to sham and ELFMF conditions, and assessed cell survival and function. We used our previously developed ELFMF exposure unit (a sinusoidal magnetic field at a frequency of 60 Hz, 5 mT) to culture cells under exposure to ELFMF conditions. We found that exposure to ELFMF for 5 days in the absence of glucose increased cell number, exposure for 2 days in the absence of glucose and for 5 days with 100 mg/dl glucose increased the insulin secretion to the culture medium, and exposure for 2 and 5 days with 40 and 100 mg/dl glucose increased intracellular insulin concentration in HIT-T15 cells. The increase in cell number under apoptotic culture conditions by exposure to ELFMF could lead to new therapeutic concepts in the treatment of diabetes. The ELFMF-induced increase in intracellular insulin concentration could be utilized to develop culture conditions to enhance intracellular insulin concentration in insulin-secreting cells that would be useful for cell transplantation to cure diabetes mellitus.


Assuntos
Glucose/metabolismo , Células Secretoras de Insulina/fisiologia , Células Secretoras de Insulina/efeitos da radiação , Insulina/metabolismo , Animais , Linhagem Celular , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos da radiação , Cricetinae , Relação Dose-Resposta à Radiação , Campos Eletromagnéticos , Células Secretoras de Insulina/citologia , Doses de Radiação
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