Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 53
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Nat Commun ; 12(1): 5068, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417460

RESUMO

p53 regulates several signaling pathways to maintain the metabolic homeostasis of cells and modulates the cellular response to stress. Deficiency or excess of nutrients causes cellular metabolic stress, and we hypothesized that p53 could be linked to glucose maintenance. We show here that upon starvation hepatic p53 is stabilized by O-GlcNAcylation and plays an essential role in the physiological regulation of glucose homeostasis. More specifically, p53 binds to PCK1 promoter and regulates its transcriptional activation, thereby controlling hepatic glucose production. Mice lacking p53 in the liver show a reduced gluconeogenic response during calorie restriction. Glucagon, adrenaline and glucocorticoids augment protein levels of p53, and administration of these hormones to p53 deficient human hepatocytes and to liver-specific p53 deficient mice fails to increase glucose levels. Moreover, insulin decreases p53 levels, and over-expression of p53 impairs insulin sensitivity. Finally, protein levels of p53, as well as genes responsible of O-GlcNAcylation are elevated in the liver of type 2 diabetic patients and positively correlate with glucose and HOMA-IR. Overall these results indicate that the O-GlcNAcylation of p53 plays an unsuspected key role regulating in vivo glucose homeostasis.


Assuntos
Acetilglucosamina/metabolismo , Glucose/metabolismo , Fígado/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Sequência de Bases , Restrição Calórica , Linhagem Celular , Colforsina/farmacologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Epinefrina/metabolismo , Glucagon/metabolismo , Glucocorticoides/metabolismo , Gluconeogênese/efeitos dos fármacos , Glicosilação , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Humanos , Hidrocortisona/metabolismo , Hiperglicemia/complicações , Hiperglicemia/metabolismo , Resistência à Insulina , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Fígado/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/complicações , Obesidade/metabolismo , Fosfoenolpiruvato Carboxiquinase (GTP)/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica/efeitos dos fármacos , Ácido Pirúvico/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transcrição Genética/efeitos dos fármacos , Proteína Supressora de Tumor p53/genética
3.
Drug Deliv Transl Res ; 11(2): 524-545, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33575972

RESUMO

The potential of nanoemulsions for the oral administration of peptides is still in its early stage. The aim of the present work was to rationally design, develop, and fully characterize a new nanoemulsion (NE) intended for the oral administration of hydrophobically modified insulin (HM-insulin). Specific components of the NE were selected based on their enhancing permeation properties as well as their ability to improve insulin association efficiency (Miglyol 812, sodium taurocholate), stability in the intestinal fluids, and mucodiffusion (PEGylated phospholipids and poloxamer 407). The results showed that the NE co-existed with a population of micelles, forming a mixed system that exhibited a 100% of HM-insulin association efficiency. The nanosystem showed good stability and miscibility in different bio-relevant media and displayed an acceptable mucodiffusive behavior in porcine mucus. In addition, it exhibited a high interaction with cell mono-cultures (Caco -2 and C2BBe1 human colon carcinoma Caco-2 clone cells) and co-cultures (C2BBe1 human colon carcinoma Caco-2 clone/HT29-MTX cells). The internalization in Caco-2 monolayers was also confirmed by confocal microscopy. Finally, the promising in vitro behavior of the nanosystem in terms of overcoming the biological barriers of the intestinal tract was translated into a moderate, although significant, hypoglycemic response (≈ 20-30%), following intestinal administration to both healthy and diabetic rat models. Overall, this information underlines the crucial steps to address when designing peptide-based nanoformulations to successfully overcome the intestinal barriers associated to the oral modality of administration.

4.
Int J Obes (Lond) ; 45(3): 502-514, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33139887

RESUMO

BACKGROUND/OBJECTIVES: Liver-expressed antimicrobial peptide 2 (LEAP-2) was recently identified as an endogenous non-competitive allosteric antagonist of the growth hormone secretagogue receptor 1a (GHSR1a). LEAP-2 blunts ghrelin-induced feeding and its plasma levels are modulated in response to nutritional status in humans. Despite the relevant role of ghrelin in childhood, puberty, and childhood obesity, the potential implication of LEAP-2 in these aspects remains totally unknown. We aimed to investigate the regulation of circulating plasma LEAP-2 in childhood and adolescent either lean or obese. METHODS AND RESULTS: Plasma levels of LEAP-2 were analyzed in a cross-sectional study with lean and obese children and adolescents (n = 150). Circulating LEAP-2 levels were significantly higher in girls than in boys independently of whether they were obese or lean. In addition, LEAP-2 was significantly increased (p < 0.001) in pubertal than in prepubertal girls, while no changes were found in boys between both developmental stages. Moreover, in girls LEAP-2 was positively correlated with insulin, IGF-1, HOMA-IR and triglycerides and negatively with ghrelin. In boys, LEAP-2 was positively correlated with leptin and negatively with vitamin D levels. CONCLUSION: This study reveals a sexual dimorphism in LEAP-2 levels in children and adolescents. These changes and the higher levels during puberty imply that LEAP-2 may contribute to some of the biological adaptations occurring during pubertal development in terms of food intake, energy balance, growth rate, and puberty onset. Future studies assessing LEAP-2 levels in longitudinal studies and its implications in growth rate, puberty onset, and reproductive hormones will help to understand the relevance of this hormone in this stage of life.

5.
J Pharm Sci ; 110(1): 292-300, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33152374

RESUMO

New therapeutic approaches have been developed during recent years for the management of diabetic patients, with glucagon-like peptides analogues (GLP-1 analogues) emerging as one of the most useful therapies. However, as with human insulin analogues, translation of GLP-1 analogues into oral pharmaceutical products has been limited due to reduced oral bioavailability. Nanoparticle (NP) formulations have been investigated due to their potential to protect the drug cargo and enhance bioavailability. This study describes the pre-clinical development of a cyclodextrin-based NP formulation containing the GLP-1 analogue liraglutide for intestinal administration. A cationic amphiphilic cyclodextrin (click propyl-amine cyclodextrin (CD)) was selected as the primary complexing agent for the peptide. The resulting NPs presented an average size of 101 ± 8 nm, low polydispersity index (0.240), a negative zeta potential (-35 ± 7 mV), complete association efficiency and peptide loading of 5.0%. The optimized prototype exhibited colloidal stability in intestinal-biorelevant media up to 4 h, protecting the entrapped liraglutide from degradation by proteolytic enzymes. Intestinal administration in rats revealed effective protection and delivery of liraglutide, with a similar pharmacological response in blood glucose levels relative to subcutaneous administration of free solution. These results demonstrate the potential of the CD based formulation for further development.


Assuntos
Ciclodextrinas , Nanopartículas , Animais , Humanos , Hipoglicemiantes , Liraglutida , Peptídeos , Ratos
6.
Nutrients ; 12(4)2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32268520

RESUMO

Rheumatoid arthritis (RA) is a debilitating, chronic, inflammatory, autoimmune disease associated with cachexia. The substitutive therapy of gut hormone ghrelin has been pointed at as a potential countermeasure for the management of metabolic and inflammatory complications in RA. The recent discovery of liver-expressed antimicrobial peptide 2 (LEAP2) as an endogenous inverse agonist/antagonist of the ghrelin receptor makes feasible the development of a more rational pharmacological approach. This work aimed to assess the serum LEAP2 levels, in a cohort of RA patients, in comparison with healthy individuals and determine its correlation with inflammatory parameters. LEAP2 levels were determined by a commercial ELISA kit, plasma C-reactive protein (CRP) levels were evaluated using immunoturbidimetry, and serum levels of inflammatory mediators, namely IL-6, IL-8, IL-1ß, MIP1α, MCP1, and LCN2, were measured by XMap multiplex assay. LEAP2 serum levels were significantly increased in RA patients (n = 101) compared with control subjects (n = 26). Furthermore, the LEAP2 levels significantly correlated with CRP and inflammatory cytokines, but not with BMI. These data reveal LEAP2 as a new potential RA biomarker and indicated the pharmacological control of LEAP2 levels as a novel approach for the treatment of diseases with alterations on the ghrelin levels, such as rheumatoid cachexia.


Assuntos
Peptídeos Catiônicos Antimicrobianos/sangue , Artrite Reumatoide/sangue , Receptores de Grelina/antagonistas & inibidores , Biomarcadores/sangue , Proteínas Sanguíneas , Proteína C-Reativa/metabolismo , Citocinas/sangue , Feminino , Humanos , Masculino , Receptores de Grelina/sangue
7.
Mol Nutr Food Res ; 63(2): e1801096, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30383332

RESUMO

SCOPE: The tumor suppressor p107, a pocket protein member of the retinoblastoma susceptibility protein family, plays an important role in the cell cycle and cellular adipocyte differentiation. Nonetheless, the mechanism by which it influences whole body Energy homeostasis is unknown. METHODS AND RESULTS: The phenotype of p107 knockout (KO) mixed-background C57BL6/129 mice phenotype is studied by focusing on the involvement of white and brown adipose tissue (WAT and BAT) in energy metabolism. It is shown that p107 KO mice are leaner and have high-fat diet resistence. This phenomenon is explained by an increase of energy expenditure. The higher energy expenditure is caused by the activation of thermogenesis and may be mediated by both BAT and the browning of WAT. Consequently, it leads to the resistance of p107 KO mice to high-fat diet effects, prevention of liver steatosis, and improvement of the lipid profile and glucose homeostasis. CONCLUSION: These data allowed the unmasking of a mechanism by which a KO of p107 prevents diet-induced obesity by increasing energy expenditure via increased thermogenesis in BAT and browning of WAT, indicating the relevance of p107 as a modulator of metabolic activity of both brown and white adipocytes. Therefore, it can be targeted for the development of new therapies to ameliorate the metabolic syndrome.


Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Metabolismo Energético , Proteína p107 Retinoblastoma-Like/fisiologia , Termogênese , Animais , Dieta Hiperlipídica , Fígado Gorduroso/prevenção & controle , Glucose/metabolismo , Resistência à Insulina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína p107 Retinoblastoma-Like/deficiência
8.
J Control Release ; 291: 157-168, 2018 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-30343137

RESUMO

Peptides represent a promising therapeutic class with the potential to alleviate many severe diseases. A key limitation of these active molecules relies on the difficulties for their efficient oral administration. The objective of this work has been the rational design of polymer nanocapsules (NCs) intended for the oral delivery of peptide drugs. For this purpose, we selected insulin glulisine as a model peptide. The polymer shell of the NCs was made of a single layer of protamine, a cationic polypeptide selected for its cell penetration properties, or a double protamine/polysialic acid (PSA) layer. Insulin glulisine-loaded protamine and protamine/PSA NCs, prepared by the solvent displacement method, exhibited a size that varied in the range of 200-400 nm and a neutral surface charge (from +8 mV to -6 mV), depending on the formulation. The stability of the encapsulated peptide was assessed using circular dichroism and an in vitro cell activity study. Colloidal stability studies were also performed in simulated intestinal media containing enzymes and the results indicated that protamine NCs were stable and able to protect insulin from the harsh intestinal environment, and that this capacity could be further enhanced with a double PSA-Protamine layer. These NCs were freeze-dried and stored at room temperature without alteration of the physicochemical properties. When the insulin-loaded protamine NCs were administered intra-intestinally to diabetic rats (12 h fasting) it resulted in a prolonged glucose reduction (60%) as compared to the control insulin solution. This work raises prospects that protamine NCs may have a potential as oral peptide delivery nanocarriers.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Insulina/análogos & derivados , Nanocápsulas/química , Protaminas/química , Ácidos Siálicos/química , Administração Oral , Animais , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Células Hep G2 , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/administração & dosagem , Insulina/uso terapêutico , Masculino , Nanocápsulas/ultraestrutura , Ratos Sprague-Dawley
9.
Int J Mol Sci ; 19(10)2018 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-30257454

RESUMO

Chemerin (also known as tazarotene-induced gene 2 and retinoic acid receptor responder 2) has been identified as an adipokine that exerts effects on many biological processes, including adipogenesis, angiogenesis, inflammation, immune responses, and food intake. This variety of effects has led to its implication in obesity and co-morbidities including diabetes and a risk of cardiovascular disease. The biological effects are mostly mediated by a so-called G protein-coupled receptor, chemokine-like receptor 1 (CMKLR1). Given the association of chemerin with obesity and related diseases, we decided to study in detail the regulation of chemerin and CMKLR1 expression in white adipose tissue (WAT). Specifically, we focused on their expression levels in physiological and pathophysiological settings involved in energy balance: e.g., fasting, postnatal development, and gender. We used Sprague Dawley rats with different nutritional statuses, levels of hormonal deficiency, and states of development as well as ob/ob (leptin-deficient) mice. We analysed the protein expression of both the ligand and receptor (chemerin and CMKLR1) in gonadal WAT by western blotting. We found that chemerin and CMKLR1 protein levels were regulated in WAT by different conditions associated with metabolic changes such as nutritional status, sex steroids, pregnancy, and food composition. Our data indicate that regulation of the expression of this new adipokine and its receptor by nutritional status and gonadal hormones may be a part of the adaptive mechanisms related to altered fat mass and its metabolic complications.


Assuntos
Receptores de Quimiocinas/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Quimiocinas/análise , Quimiocinas/metabolismo , Dieta Hiperlipídica/efeitos adversos , Ingestão de Alimentos , Feminino , Hormônios Esteroides Gonadais/metabolismo , Hiperlipidemias/etiologia , Hiperlipidemias/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/análise , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Leptina/análise , Leptina/metabolismo , Masculino , Estado Nutricional , Gravidez , Ratos Sprague-Dawley , Receptores de Quimiocinas/análise , Caracteres Sexuais
10.
Artigo em Inglês | MEDLINE | ID: mdl-29904371

RESUMO

Mitochondria are important organelles for the adaptation to energy demand that play a central role in bioenergetics metabolism. The mitochondrial architecture and mitochondrial machinery exhibits a high degree of adaptation in relation to nutrient availability. On the other hand, its disruption markedly affects energy homeostasis. The brain, more specifically the hypothalamus, is the main hub that controls energy homeostasis. Nevertheless, until now, almost all studies in relation to mitochondrial dysfunction and energy metabolism have focused in peripheral tissues like brown adipose tissue, muscle, and pancreas. In this review, we highlight the relevance of the hypothalamus and the influence on mitochondrial machinery in its function as well as its consequences in terms of alterations in both energy and metabolic homeostasis.

11.
J Endocrinol ; 238(3): 177-186, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29914932

RESUMO

Current evidence suggests that estradiol (E2), the main ovarian steroid, modulates energy balance by regulating both feeding and energy expenditure at the central level, through the energy sensor AMP-activated protein kinase (AMPK). We hypothesized that the hypothalamic mechanistic target of rapamycin (mTOR) pathway, a well-established nutrient sensor and modulator of appetite and puberty, could also mediate the anorectic effect of E2. Our data showed that ovariectomy (OVX) elicited a marked downregulation of the mTOR signaling in the arcuate nucleus of the hypothalamus (ARC), an effect that was reversed by either E2 replacement or central estrogen receptor alpha (ERα) agonism. The significance of this molecular signaling was given by the genetic inactivation of S6 kinase B1 (S6K1, a key downstream mTOR effector) in the ARC, which prevented the E2-induced hypophagia and weight loss. Overall, these data indicate that E2 induces hypophagia through modulation of mTOR pathway in the ARC.


Assuntos
Anorexia/induzido quimicamente , Anorexia/metabolismo , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Estradiol/farmacologia , Serina-Treonina Quinases TOR/metabolismo , Animais , Depressores do Apetite/farmacologia , Núcleo Arqueado do Hipotálamo/metabolismo , Peso Corporal/efeitos dos fármacos , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Feminino , Ovariectomia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Serina-Treonina Quinases TOR/fisiologia
12.
J Control Release ; 276: 125-139, 2018 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-29518466

RESUMO

The objective of this work was the development of a new drug nanocarrier intended to overcome the barriers associated to the oral modality of administration and to assess its value for the systemic or local delivery of peptides. The nanocarrier was rationally designed taking into account the nature of the intestinal barriers and was loaded with insulin, which was selected as a model peptide. The nanocarrier consisted of a complex between insulin and a hydrophobically-modified cell penetrating peptide (CPP), enveloped by a protecting polymer. The selected CPP was octaarginine (r8), chemically conjugated with cholesterol (Chol) or lauric acid (C12), whereas the protecting polymer was poly (glutamic acid)-poly (ethylene glycol) (PGA-PEG). This enveloping material was intended to preserve the stability of the nanocomplex in the intestinal medium and facilitate its diffusion across the intestinal mucus. The enveloped nanocomplexes (ENCPs) exhibited a number of key features, namely (i) a unimodal size distribution with a mean size of 200 nm and a neutral zeta potential, (ii) the capacity to associate insulin (~100% association efficiency) and protect it from degradation in simulated intestinal fluids, (iii) the ability to diffuse through intestinal mucus and, most importantly, (iv) the capacity to interact with the Caco-2 model epithelium, resulting in a massive insulin cell uptake (47.59 ±â€¯5.79%). This enhanced accumulation of insulin at the epithelial level was not translated into an enhanced insulin transport. In fact, only 2% of insulin was transported across the monolayer, and this was correlated with a moderate response of insulin following oral administration to healthy rats. Despite of this, the accumulation of the insulin-loaded nanocarriers in the intestinal mucosa could be verified in vivo upon their labeling with 99mTc. Overall, these data underline the capacity of the nanocarriers to overcome substantial barriers associated to the oral modality of administration and to facilitate the accumulation of the associated peptide at the intestinal level.


Assuntos
Peptídeos Penetradores de Células/administração & dosagem , Portadores de Fármacos/administração & dosagem , Insulina/administração & dosagem , Nanoestruturas/administração & dosagem , Oligopeptídeos/administração & dosagem , Polietilenoglicóis/administração & dosagem , Ácido Poliglutâmico/administração & dosagem , Administração Oral , Animais , Células CACO-2 , Colesterol/química , Humanos , Mucosa Intestinal/metabolismo , Ácidos Láuricos/química , Masculino , Ratos Sprague-Dawley , Ratos Wistar
13.
Nanoscale ; 10(2): 603-613, 2018 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-29235598

RESUMO

Nanoparticulate based drug delivery systems have been extensively studied to efficiently encapsulate and deliver peptides orally. However, most of the existing data mainly focus on the nanoparticles as a drug carrier, but the ability of nanoparticles having a biological effect has not been exploited. Herein, we hypothesize that nanostructured lipid carriers (NLCs) could activate the endogenous glucagon-like peptide-1 (GLP-1) secretion and also act as oral delivery systems for GLP-1 analogs (exenatide and liraglutide). NLCs effectively encapsulated the peptides, the majority of which were only released under the intestinal conditions. NLCs, with and without peptide encapsulation, showed effective induction of GLP-1 secretion in vitro from the enteroendocrinal L-cells (GLUTag). NLCs also showed a 2.9-fold increase in the permeability of exenatide across the intestinal cell monolayer. The intestinal administration of the exenatide and liraglutide loaded NLCs did not demonstrate any glucose lowering effect on normal mice. Further, ex vivo studies depicted that the NLCs mainly adhered to the mucus layer. In conclusion, this study demonstrates that NLCs need further optimization to overcome the mucosal barrier in the intestine; nonetheless, this study also presents a promising strategy to use a dual-action drug delivery nanosystem which synergizes its own biological effect and that of the encapsulated drug molecule.


Assuntos
Portadores de Fármacos/química , Peptídeo 1 Semelhante ao Glucagon/agonistas , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Lipídeos/química , Nanoestruturas , Animais , Células CACO-2 , Exenatida/administração & dosagem , Humanos , Jejuno/efeitos dos fármacos , Liraglutida/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos NOD , Tamanho da Partícula , Ratos Sprague-Dawley
15.
World J Gastroenterol ; 23(35): 6403-6411, 2017 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-29085189

RESUMO

AIM: To determine whether Nucb2/nesfatin1 production is regulated by the cannabinoid system through the intracellular mTOR pathway in the stomach. METHODS: Sprague Dawley rats were treated with vehicle, rimonabant, rapamycin or rapamycin+rimonabant. Gastric tissue obtained from the animals was used for biochemical assays: Nucb2 mRNA measurement by real time PCR, gastric Nucb2/nesfatin protein content by western blot, and gastric explants to obtain gastric secretomes. Nucb2/nesfatin levels were measured in gastric secretomes and plasma using enzyme-linked immunosorbent assay. RESULTS: The inhibition of cannabinoid receptor 1 (CB1) by the peripheral injection of an inverse agonist, namely rimonabant, decreases food intake and increases the gastric secretion and circulating levels of Nucb2/nesfatin-1. In addition, rimonabant treatment activates mTOR pathway in the stomach as showed by the increase in pmTOR/mTOR expression in gastric tissue obtained from rimonabant treated animals. These effects were confirmed by the use of a CB1 antagonist, AM281. When the intracellular pathway mTOR/S6k was inactivated by chronic treatment with rapamycin, rimonabant treatment was no longer able to stimulate the gastric secretion of Nucb2/nesfatin-1. CONCLUSION: The peripheral cannabinoid system regulates food intake through a mechanism that implies gastric production and release of Nucb2/Nesfatin-1, which is mediated by the mTOR/S6k pathway.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Antagonistas de Receptores de Canabinoides/farmacologia , Proteínas de Ligação a DNA/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Receptor CB1 de Canabinoide/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Animais , Proteínas de Ligação ao Cálcio/sangue , Proteínas de Ligação a DNA/sangue , Ingestão de Alimentos/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Masculino , Modelos Animais , Morfolinas/farmacologia , Proteínas do Tecido Nervoso/sangue , Nucleobindinas , Fosforilação , Piperidinas/farmacologia , Pirazóis/farmacologia , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Proteínas Quinases S6 Ribossômicas/metabolismo , Rimonabanto , Sirolimo/farmacologia , Serina-Treonina Quinases TOR/antagonistas & inibidores
16.
Diabetologia ; 60(12): 2453-2462, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28956081

RESUMO

AIMS/HYPOTHESIS: The identification of mediators in the pathogenesis of type 2 diabetes mellitus is essential for the full understanding of this disease. Protein kinases are especially important because of their potential as pharmacological targets. The goal of this study was to investigate whether mammalian sterile-20 3 (MST3/STK24), a stress-regulated kinase, is involved in metabolic alterations in obesity. METHODS: Glucose regulation of Mst3 (also known as Stk24)-knockout mice was analysed both in 129;C57 mixed background mice and in C57/BL6J mice fed normally or with a high-fat diet (HFD). This work was complemented with an analysis of the insulin signalling pathway in cultured human liver cells made deficient in MST3 using RNA interference. RESULTS: MST3 is phosphorylated in the livers of mice subject to an obesity-promoting HFD, and its deficiency lowers the hyperglycaemia, hyperinsulinaemia and insulin resistance that the animals develop with this diet, an effect that is seen even without complete inactivation of the kinase. Lack of MST3 results in activation of the insulin signalling pathway downstream of IRS1, in both cultured liver cells and the liver of animals after HFD. This effect increases the inhibition of forkhead box (FOX)O1, with subsequent downregulation of the expression of gluconeogenic enzymes. CONCLUSIONS/INTERPRETATION: MST3 inhibits the insulin signalling pathway and is important in the development of insulin resistance and impaired blood glucose levels after an HFD.


Assuntos
Glicemia/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica/efeitos adversos , Jejum/sangue , Feminino , Gluconeogênese/fisiologia , Células Hep G2 , Humanos , Resistência à Insulina/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Serina-Treonina Quinases/genética
18.
Nat Commun ; 8: 15111, 2017 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-28480888

RESUMO

p53 family members control several metabolic and cellular functions. The p53 ortholog p63 modulates cellular adaptations to stress and has a major role in cell maintenance and proliferation. Here we show that p63 regulates hepatic lipid metabolism. Mice with liver-specific p53 deletion develop steatosis and show increased levels of p63. Down-regulation of p63 attenuates liver steatosis in p53 knockout mice and in diet-induced obese mice, whereas the activation of p63 induces lipid accumulation. Hepatic overexpression of N-terminal transactivation domain TAp63 induces liver steatosis through IKKß activation and the induction of ER stress, the inhibition of which rescues the liver functions. Expression of TAp63, IKKß and XBP1s is also increased in livers of obese patients with NAFLD. In cultured human hepatocytes, TAp63 inhibition protects against oleic acid-induced lipid accumulation, whereas TAp63 overexpression promotes lipid storage, an effect reversible by IKKß silencing. Our findings indicate an unexpected role of the p63/IKKß/ER stress pathway in lipid metabolism and liver disease.


Assuntos
Estresse do Retículo Endoplasmático , Fígado Gorduroso/metabolismo , Quinase I-kappa B/metabolismo , Fígado/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Adulto , Animais , Fígado Gorduroso/genética , Fígado Gorduroso/fisiopatologia , Feminino , Hepatócitos/metabolismo , Humanos , Quinase I-kappa B/genética , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Transativadores/genética , Transativadores/metabolismo , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/genética , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismo
19.
J Control Release ; 263: 4-17, 2017 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-28235590

RESUMO

The aim of this work was to rationally design and characterize nanocapsules (NCs) composed of an oily core and a polyarginine (PARG) shell, intended for oral peptide delivery. The cationic polyaminoacid, PARG, and the oily core components were selected based on their penetration enhancing properties. Insulin was adopted as a model peptide to assess the performance of the NCs. After screening numerous formulation variables, including different oils and surfactants, we defined a composition consisting of oleic acid, sodium deoxycholate (SDC) and Span 80. This selected NCs composition, produced by the solvent displacement technique, exhibited the following key features: (i) an average size of 180nm and a low polydispersity (0.1), (ii) a high insulin association efficacy (80-90% AE), (iii) a good colloidal stability upon incubation in simulated intestinal fluids (SIF, FaSSIF-V2, FeSSIF-V2), and (iv) the capacity to control the release of the associated insulin for >4h. Furthermore, using the Caco-2 model cell line, PARG nanocapsules were able to interact with the enterocytes, and reversibly modify the TEER of the monolayer. Both cell adhesion and membrane permeabilization could account for the pronounced transport of the NCs-associated insulin (3.54%). This improved interaction was also visualized by confocal fluorescent microscopy following oral administration of PARG nanocapsulesto mice. Finally, in vivo efficacy studies performed in normoglycemic rats showed a significant decrease in their plasma glucose levels after treatment. In conclusion, here we disclose key formulation elements for making possible the oral administration of peptides.


Assuntos
Portadores de Fármacos/administração & dosagem , Hipoglicemiantes/administração & dosagem , Insulina/administração & dosagem , Absorção Intestinal , Nanocápsulas/administração & dosagem , Peptídeos/administração & dosagem , Animais , Glicemia/efeitos dos fármacos , Células CACO-2 , Portadores de Fármacos/química , Desenho de Fármacos , Liberação Controlada de Fármacos , Humanos , Hipoglicemiantes/química , Insulina/química , Mucosa Intestinal/metabolismo , Secreções Intestinais/química , Masculino , Nanocápsulas/química , Peptídeos/química , Ratos Sprague-Dawley
20.
J Control Release ; 243: 109-120, 2016 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-27720993

RESUMO

Single-layer protamine and double layer polysialic acid (PSA)/protamine nanocapsules (NCs) were designed in order to be used as carriers to facilitate the transport of macromolecules across the intestinal epithelium. The rational for the design of these NCs was based on that protamine is a non-toxic yet potent cell-penetrating peptide, capable of translocating protein cargos through cell membranes, while PSA is a low molecular weight polysaccharide used to enhance the stability of macromolecules and nanocarriers. The aim of this work was to study in vitro the mechanism of interaction of these NCs with different intestinal cell models (Caco-2, Caco-2/Raji mimicking follicle associated epithelium and Caco-2/HT29-MTX to study the effect of mucus). For this, a fluorescent marker, TAMRA was covalently linked to protamine. The interaction and transport of the NCs with the Caco-2 cells was found to be concentration, temperature and size dependent. In all cases, the double layer PSA-protamine NCs exhibited a significantly higher transport compared to protamine NCs. On the other hand, the transport of the NCs was significantly higher in the co-culture (Caco-2/Raji monolayer) compared to the monoculture model (Caco-2 monolayer), implying that M cells are involved in the transport of these nanosystems. The formulations, administered intra-jejunally to healthy rats (4h fasting) resulted in a moderate reduction of the glucose levels (20% reduction), which lasted for up to 4h. This work raises prospects that protamine-based nanocapsules may have the potential as oral peptide delivery nanocarriers.


Assuntos
Portadores de Fármacos/química , Nanocápsulas , Protaminas/química , Ácidos Siálicos/química , Animais , Transporte Biológico , Células CACO-2 , Química Farmacêutica/métodos , Técnicas de Cocultura , Sistemas de Liberação de Medicamentos , Humanos , Absorção Intestinal , Mucosa Intestinal/metabolismo , Masculino , Tamanho da Partícula , Permeabilidade , Ratos , Ratos Sprague-Dawley , Temperatura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...