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1.
Menopause ; 28(4): 423-430, 2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33399320

RESUMO

OBJECTIVES: Menopause is often characterized by detrimental metabolic changes, such as obesity, insulin resistance, and impaired glucose tolerance, often requiring treatment. KeyBioscience Peptides (KBPs) are Dual Amylin and Calcitonin Receptor Agonists which have shown promising metabolic effects in rats. The objective of this study was to investigate the in vivo effect of KBP on the metabolic health in a model driven by unhealthy diet, age, and menopause. METHODS: Female Sprague Dawley rats were fed a high-fat diet (HFD) for 3 months before the initiation of the study. At 6 months of age the rats were randomized into groups (n = 12) and subjected to ovariectomy surgery and treatment with KBP: (1) Lean-Sham, (2) HFD-Sham, (3) Lean-OVX, (4) HFD-OVX, (5) HFD-OVX-KBP (10 µg/kg/d), (6) HFD-OVX-KBP (20 µg/kg/d), (7) HFD-OVX-EE2 (30 µg/d 17a-ethynylestradiol). Body weight, food intake, oral glucose tolerance tests (OGTTs), subcutaneous fat, visceral fat, liver weight, and uterus weight were assessed during the 6-month study. Statistical analyses were conducted by one-way ANOVA with Tukey post-hoc test for multiple comparisons. RESULTS: Combination of OVX and HFD led to significant induction of obesity (31% weight increase, P < 0.001) and insulin resistance (13% increase in tAUCglucose during OGTT P < 0.01) compared with the relevant control groups (P < 0.05), and this could be completely rescued by EE2 therapy confirming the model system (P < 0.05).Treatment of OVX-HFD rats with KBP for 26 weeks led to a significant reduction in body weight (13%, P < 0.001) in the high dose and 9% (P < 0.01) in the low dose, with corresponding improvements in fat depot sizes, all compared with HFD-OVX controls. As expected, food intake was suppressed, albeit mainly in the first 2 weeks of treatment, resulting in a reduction of overall caloric intake by 6.5% (P < 0.01) and 12.5% (P < 0.001) in the low and high doses respectively. Furthermore, treatment with KBP reduced the weight of visceral and subcutaneous fat tissues. Finally, KBP treatment significantly improved glucose tolerance, assessed using OGTTs at weeks 8, 16, and 24. CONCLUSIONS: The data presented here clearly indicate a positive and sustained effect of KBP treatment on body weight loss, fat depot size, and improved glucose tolerance, illustrating the potential of KBPs as treatments for metabolic complications of overweight and menopause.


Assuntos
Agonistas dos Receptores da Amilina , Receptores da Calcitonina , Animais , Peso Corporal , Calcitonina , Dieta Hiperlipídica , Feminino , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Obesidade/tratamento farmacológico , Ovariectomia , Ratos , Ratos Sprague-Dawley
2.
Nat Commun ; 12(1): 183, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420039

RESUMO

We have reported that autophagy is crucial for clearance of amyloidogenic human IAPP (hIAPP) oligomer, suggesting that an autophagy enhancer could be a therapeutic modality against human diabetes with amyloid accumulation. Here, we show that a recently identified autophagy enhancer (MSL-7) reduces hIAPP oligomer accumulation in human induced pluripotent stem cell-derived ß-cells (hiPSC-ß-cells) and diminishes oligomer-mediated apoptosis of ß-cells. Protective effects of MSL-7 against hIAPP oligomer accumulation and hIAPP oligomer-mediated ß-cell death are significantly reduced in cells with knockout of MiTF/TFE family members such as Tfeb or Tfe3. MSL-7 improves glucose tolerance and ß-cell function of hIAPP+ mice on high-fat diet, accompanied by reduced hIAPP oligomer/amyloid accumulation and ß-cell apoptosis. Protective effects of MSL-7 against hIAPP oligomer-mediated ß-cell death and the development of diabetes are also significantly reduced by ß-cell-specific knockout of Tfeb. These results suggest that an autophagy enhancer could have therapeutic potential against human diabetes characterized by islet amyloid accumulation.


Assuntos
Amiloide/metabolismo , Proteínas Amiloidogênicas/metabolismo , Autofagia/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/genética , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Animais , Apoptose/fisiologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Técnicas de Inativação de Genes , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células Secretoras de Insulina , Macroautofagia/fisiologia , Camundongos , Camundongos Transgênicos
3.
Int J Biol Macromol ; 169: 428-435, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33347933

RESUMO

In this study, we have investigated a series of hydroxylated 2-phenylbenzofurans compounds for their inhibitory activity against α-amylase and α-glucosidase activity. Inhibitors of carbohydrate degrading enzymes seem to have an important role as antidiabetic drugs. Diabetes mellitus is a wide-spread metabolic disease characterized by elevated levels of blood glucose. The most common is type 2 diabetes, which can lead to severe complications. Since the aggregates of islet amyloid polypeptide (IAPP) are common in diabetic patients, the effect of compounds to inhibit amyloid fibril formation was also determined. All the compounds assayed showed to be more active against α-glucosidase. Compound 16 showed the lowest IC50 value of the series, and it is found to be 167 times more active than acarbose, the reference compound. The enzymatic activity assays showed that compound 16 acts as a mixed-type inhibitor of α-glucosidase. Furthermore, compound 16 displayed effective inhibition of IAPP aggregation and it manifested no significant cytotoxicity. To predict the binding of compound 16 to IAPP and α-glucosidase protein complexes, molecular docking studies were performed. Altogether, our results support that the 2-phenylbenzofuran derivatives could represent a promising candidate for developing molecules able to modulate multiple targets involved in diabetes mellitus disorder.


Assuntos
Benzofuranos/farmacologia , Inibidores de Glicosídeo Hidrolases/farmacologia , alfa-Amilases/antagonistas & inibidores , Amiloide/química , Benzofuranos/química , Glicemia/efeitos dos fármacos , Diabetes Mellitus Tipo 2/metabolismo , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/metabolismo , Humanos , Hidroxilação , Hipoglicemiantes/farmacologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Simulação de Acoplamento Molecular , Estudos Prospectivos , alfa-Amilases/química , alfa-Glucosidases/metabolismo
4.
PLoS One ; 15(8): e0237667, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32833960

RESUMO

BACKGROUND AND AIMS: This is the first time that obesity and diabetes mellitus (DM) as protein conformational diseases (PCD) are reported in children and they are typically diagnosed too late, when ß-cell damage is evident. Here we wanted to investigate the level of naturally-ocurring or real (not synthetic) oligomeric aggregates of the human islet amyloid polypeptide (hIAPP) that we called RIAO in sera of pediatric patients with obesity and diabetes. We aimed to reduce the gap between basic biomedical research, clinical practice-health decision making and to explore whether RIAO work as a potential biomarker of early ß-cell damage. MATERIALS AND METHODS: We performed a multicentric collaborative, cross-sectional, analytical, ambispective and blinded study; the RIAO from pretreated samples (PTS) of sera of 146 pediatric patients with obesity or DM and 16 healthy children, were isolated, measured by sound indirect ELISA with novel anti-hIAPP cytotoxic oligomers polyclonal antibody (MEX1). We carried out morphological and functional studied and cluster-clinical data driven analysis. RESULTS: We demonstrated by western blot, Transmission Electron Microscopy and cell viability experiments that RIAO circulate in the blood and can be measured by ELISA; are elevated in serum of childhood obesity and diabetes; are neurotoxics and works as biomarkers of early ß-cell failure. We explored the range of evidence-based medicine clusters that included the RIAO level, which allowed us to classify and stratify the obesity patients with high cardiometabolic risk. CONCLUSIONS: RIAO level increases as the number of complications rises; RIAOs > 3.35 µg/ml is a predictor of changes in the current indicators of ß-cell damage. We proposed a novel physio-pathological pathway and shows that PCD affect not only elderly patients but also children. Here we reduced the gap between basic biomedical research, clinical practice and health decision making.


Assuntos
Diabetes Mellitus Tipo 1/patologia , Diabetes Mellitus Tipo 2/patologia , Células Secretoras de Insulina/patologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Obesidade/patologia , Estrutura Quaternária de Proteína , Adolescente , Animais , Linhagem Celular , Sobrevivência Celular , Células Cultivadas , Criança , Pré-Escolar , Estudos Transversais , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/sangue , Polipeptídeo Amiloide das Ilhotas Pancreáticas/toxicidade , Polipeptídeo Amiloide das Ilhotas Pancreáticas/ultraestrutura , Microscopia Eletrônica de Transmissão , Neurônios/efeitos dos fármacos , Obesidade/sangue , Obesidade/complicações , Projetos Piloto , Cultura Primária de Células , Multimerização Proteica , Ratos , Testes de Toxicidade Aguda
5.
Adv Exp Med Biol ; 1250: 159-176, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32601944

RESUMO

Diabetes mellitus type 2 (type-2 diabetes) is a metabolic disorder characterized by the increased blood glucose concentration and insulin resistance in peripheral tissues (e.g., muscles and adipose tissue). The initiation of the pathological cascade of events that lead to type-2 diabetes has been subject of debate; however, it has been commonly accepted that the oversecretion of human islet amyloid polypeptide (hIAPP, a hormone co-secreted with insulin) by the pancreatic 𝛽-cells is the main trigger of type-2 diabetes. In fact, 90% of the type-2 diabetes patients present hIAPP deposits in the extracellular space of the 𝛽-cells. These hIAPP supramolecular arrangements (both fibrillar and oligomeric) have been reported to be the origin of cytotoxicity, which leads to 𝛽-cell dysfunction through a series of different mechanisms, including the interaction of hIAPP oligomers with the cell membrane that leads to the influx of Ca2+ and increase in the cellular oxidative stress, among others. This overview shows the importance of developing type-2 diabetes treatment strategies able to (1) remodel of the secondary structure of cytotoxic hIAPP oligomers entrapping them into off-pathway nontoxic species and (2) reestablish physiological levels of oxidative stress. Natural polyphenols are a class of antioxidant compounds that are able to perform both functions. Herein we review the published literature of the most studied polyphenols, in particular for their ability to remodel the hIAPP aggregation pathway, to rescue the in vitro pancreatic 𝛽-cell viability and function, as well as to perform under a complex biological environment, i.e., in vivo animal models and clinical trials. Overall, natural polyphenols are able to control the cytotoxic hIAPP aggregation and minimize hIAPP-mediated cellular dysfunction and can be considered as important lead compounds for the treatment of type-2 diabetes.


Assuntos
Diabetes Mellitus Tipo 2 , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Polifenóis , Animais , Diabetes Mellitus Tipo 2/fisiopatologia , Diabetes Mellitus Tipo 2/terapia , Modelos Animais de Doenças , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Polifenóis/farmacologia
6.
Yi Chuan ; 42(6): 586-598, 2020 Jun 20.
Artigo em Chinês | MEDLINE | ID: mdl-32694117

RESUMO

Human islet amyloid polypeptide (hIAPP, also known as amylin) is a co-secreting protein of insulin in human pancreatic ß-cells. It is encapsulated in vesicles and secreted out of the cells with insulin. hIAPP can promote insulin secretion and regulate blood glucose homeostasis in the body under the normal physiological conditions. However, hIAPP misfolding or excessive accumulation can cause toxic effects on the ß cells, which in turn affect cell function, resulting in type 2 diabetes mellitus (T2DM) for the affected individuals. In order to eliminate the excessive accumulation of hIAPP in the cell and to maintain its normal synthetic function, we have adopted a new protein degradation technology called Trim-Away, which can degrade the target protein in a short time without affecting the mRNA transcription and translation synthesis function of the target protein. First, we overexpressed hIAPP in the rat insulinoma cells (INS1) to simulate its excessive accumulation and analyzed its effect in INS1 cells by measuring the release of LDH (lactate dehydrogenase), CCK8 activity and PI-Annexin V positive ratio. Results showed that excessive accumulation of hIAPP caused ß cell apoptosis. Second, real-time quantitative PCR analysis and ELISA detection showed that the synthesis and secretion of insulin were hindered. We used Trim-Way technology to specifically eliminate the excessive accumulation of hIAPP protein in hIAPP overexpressing INS1 cells. Cell activity experiments confirmed that clearance of hIAPP reduced the cell death phenotype. Further ELISA experiments confirmed that INS1 cells restored insulin secretion ability. This study examined the toxic effect of hIAPP excessive accumulation in INS1 cells and demonstrated the cytotoxicity clearance effect of Trim-Way technology in pancreatic ß-cells. Our research has provided a new strategy for using Trim-Away technology for treatment of diabetes.


Assuntos
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Insulinoma , Neoplasias Pancreáticas , Animais , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Neoplasias Pancreáticas/genética , Dobramento de Proteína , Ratos
7.
Nat Struct Mol Biol ; 27(7): 660-667, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32541895

RESUMO

Amyloid deposits consisting of fibrillar islet amyloid polypeptide (IAPP) in pancreatic islets are associated with beta-cell loss and have been implicated in type 2 diabetes (T2D). Here, we applied cryo-EM to reconstruct densities of three dominant IAPP fibril polymorphs, formed in vitro from synthetic human IAPP. An atomic model of the main polymorph, built from a density map of 4.2-Å resolution, reveals two S-shaped, intertwined protofilaments. The segment 21-NNFGAIL-27, essential for IAPP amyloidogenicity, forms the protofilament interface together with Tyr37 and the amidated C terminus. The S-fold resembles polymorphs of Alzheimer's disease (AD)-associated amyloid-ß (Aß) fibrils, which might account for the epidemiological link between T2D and AD and reports on IAPP-Aß cross-seeding in vivo. The results structurally link the early-onset T2D IAPP genetic polymorphism (encoding Ser20Gly) with the AD Arctic mutation (Glu22Gly) of Aß and support the design of inhibitors and imaging probes for IAPP fibrils.


Assuntos
Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Doença de Alzheimer/fisiopatologia , Substituição de Aminoácidos , Peptídeos beta-Amiloides/química , Microscopia Crioeletrônica , Diabetes Mellitus Tipo 2 , Humanos , Concentração de Íons de Hidrogênio , Polipeptídeo Amiloide das Ilhotas Pancreáticas/genética , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Modelos Moleculares , Simulação de Dinâmica Molecular , Conformação Proteica
8.
Nat Struct Mol Biol ; 27(7): 653-659, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32541896

RESUMO

Human islet amyloid polypeptide (hIAPP) functions as a glucose-regulating hormone but deposits as amyloid fibrils in more than 90% of patients with type II diabetes (T2D). Here we report the cryo-EM structure of recombinant full-length hIAPP fibrils. The fibril is composed of two symmetrically related protofilaments with ordered residues 14-37. Our hIAPP fibril structure (i) supports the previous hypothesis that residues 20-29 constitute the core of the hIAPP amyloid; (ii) suggests a molecular mechanism for the action of the hIAPP hereditary mutation S20G; (iii) explains why the six residue substitutions in rodent IAPP prevent aggregation; and (iv) suggests regions responsible for the observed hIAPP cross-seeding with ß-amyloid. Furthermore, we performed structure-based inhibitor design to generate potential hIAPP aggregation inhibitors. Four of the designed peptides delay hIAPP aggregation in vitro, providing a starting point for the development of T2D therapeutics and proof of concept that the capping strategy can be used on full-length cryo-EM fibril structures.


Assuntos
Diabetes Mellitus Tipo 2/genética , Polipeptídeo Amiloide das Ilhotas Pancreáticas/antagonistas & inibidores , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/genética , Peptídeos/química , Amiloide/química , Animais , Microscopia Crioeletrônica , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Modelos Moleculares , Mutação , Peptídeos/farmacologia , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Roedores
10.
Nat Biomed Eng ; 4(5): 507-517, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32393892

RESUMO

Treatment of patients with diabetes with insulin and pramlintide (an amylin analogue) is more effective than treatment with insulin only. However, because mixtures of insulin and pramlintide are unstable and have to be injected separately, amylin analogues are only used by 1.5% of people with diabetes needing rapid-acting insulin. Here, we show that the supramolecular modification of insulin and pramlintide with cucurbit[7]uril-conjugated polyethylene glycol improves the pharmacokinetics of the dual-hormone therapy and enhances postprandial glucagon suppression in diabetic pigs. The co-formulation is stable for over 100 h at 37 °C under continuous agitation, whereas commercial formulations of insulin analogues aggregate after 10 h under similar conditions. In diabetic rats, the administration of the stabilized co-formulation increased the area-of-overlap ratio of the pharmacokinetic curves of pramlintide and insulin from 0.4 ± 0.2 to 0.7 ± 0.1 (mean ± s.d.) for the separate administration of the hormones. The co-administration of supramolecularly stabilized insulin and pramlintide better mimics the endogenous kinetics of co-secreted insulin and amylin, and holds promise as a dual-hormone replacement therapy.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Composição de Medicamentos , Glucagon/metabolismo , Insulina/uso terapêutico , Polipeptídeo Amiloide das Ilhotas Pancreáticas/uso terapêutico , Animais , Hidrocarbonetos Aromáticos com Pontes/química , Difusão , Vias de Administração de Medicamentos , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Imidazóis/química , Insulina/administração & dosagem , Insulina/farmacocinética , Insulina/farmacologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/administração & dosagem , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacocinética , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacologia , Masculino , Polietilenoglicóis/química , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Suínos
11.
Proc Natl Acad Sci U S A ; 117(22): 12050-12061, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32414928

RESUMO

Amyloidoses (misfolded polypeptide accumulation) are among the most debilitating diseases our aging societies face. Amyloidogenesis can be catalyzed by hydrophobic-hydrophilic interfaces (e.g., air-water interface in vitro [AWI]). We recently demonstrated hydrogelation of the amyloidogenic type II diabetes-associated islet amyloid polypeptide (IAPP), a hydrophobic-hydrophilic interface-dependent process with complex kinetics. We demonstrate that human IAPP undergoes AWI-catalyzed liquid-liquid phase separation (LLPS), which initiates hydrogelation and aggregation. Insulin modulates these processes but does not prevent them. Using nonamyloidogenic rat IAPP, we show that, whereas LLPS does not require the amyloidogenic sequence, hydrogelation and aggregation do. Interestingly, both insulin and rat sequence delayed IAPP LLPS, which may reflect physiology. By developing an experimental setup and analysis tools, we show that, within the whole system (beyond the droplet stage), macroscopic interconnected aggregate clusters form, grow, fuse, and evolve via internal rearrangement, leading to overall hydrogelation. As the AWI-adsorbed gelled layer matures, its microviscosity increases. LLPS-driven aggregation may be a common amyloid feature and integral to pathology.


Assuntos
Amiloidose/patologia , Diabetes Mellitus Tipo 2/patologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Amiloide/fisiologia , Proteínas Amiloidogênicas/metabolismo , Animais , Hidrogéis , Interações Hidrofóbicas e Hidrofílicas , Insulina/metabolismo , Agregados Proteicos/fisiologia , Ratos
12.
Chemistry ; 26(34): 7609-7621, 2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32259327

RESUMO

The most common denominator of many of the neurodegenerative diseases is badly folded protein accumulation, which results in the formation of insoluble protein deposits located in different parts of the organism, causing cell death and tissue degeneration. Dendritic systems have turned out to be a promising new therapeutic approach for the treatment of these diseases due to their ability to modulate the folding of these proteins. With this perspective, and focused on type 2 diabetes (T2D), characterized by the presence of deposits containing the amyloidogenic islet amyloid polypeptide (IAPP), we demonstrate how different topologies of cationic carbosilane dendrimers inhibit the formation of insoluble protein deposits in pancreatic islets isolated from transgenic Tg-hIAPP mice. Also, the results obtained by the modification of dendritic carbosilane wedges with the chemical chaperone 4-phenylbutyric acid (4-PBA) at the focal point confirmed their potential as anti-amyloid agents with a concentration efficiency in their therapeutic action five orders of magnitude lower than that observed for free 4-PBA. Computational studies, which determined the main interaction between IAPP and dendrimers at the atomic level, support the experimental work.


Assuntos
Amiloidose/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/química , Fenilbutiratos/química , Silanos/química , Animais , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/metabolismo , Camundongos , Camundongos Transgênicos
13.
J Pharmacol Exp Ther ; 374(1): 74-83, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32317372

RESUMO

Amylin treatment improves body weight and glucose control, although it is limited by a short action and need for high doses. Dual amylin and calcitonin receptor agonists (DACRAs) are dual amylin and calcitonin receptor agonists with beneficial effects beyond those of amylin. However, to what extent the additional benefits reside in their higher potency or their targeting of the calcitonin receptor remains unclear. Here we deconstruct the receptors involved in the effects of a DACRA, KBP-088, by comparing it to rat amylin (rAMY), rat calcitonin (rCT), and their combination in obese high-fat diet (HFD) and diabetic Zucker diabetic fatty (ZDF) rats. HFD-fed Sprague-Dawley rats and ZDF rats were treated for 4 weeks with KBP-088 (5 µg/kg per day), rAMY (300 µg/kg per day), rCT (300 µg/kg per day), and the combination of rAMY and rCT (300+300 µg/kg per day) using infusion pumps. Body weight, food intake, fasting glycemia, glycated hemoglobin type A1c levels, and glucose tolerance were assessed. In obese HFD-fed rats, KBP-088, rAMY, and the combination of rAMY and rCT significantly reduced body weight and improved glucose tolerance, whereas rCT alone had no effect. In diabetic ZDF rats, rCT was efficient in lowering fasting glycemia similar to rAMY, whereas dual activation by KBP-088 and the combination of rAMY and rCT were superior to activating either receptor alone. In conclusion, calcitonin therapy regulates fasting blood glucose in a diabetic rat model, thereby underscoring the importance of calcitonin receptor activation as well as the known role of amylin receptor agonism in the potent metabolic benefits of this group of peptides. SIGNIFICANCE STATEMENT: We deconstruct the receptors activated by dual amylin and calcitonin receptor agonist (DACRA) therapy to elucidate through which receptor the beneficial metabolic effects of the DACRAs are mediated. We show that calcitonin receptor activation is important for blood glucose regulation in diabetes. This is in addition to the known metabolic beneficial role of amylin receptor activation. These data help in understanding the potent metabolic benefits of the DACRAs and underline the potential of DACRAs as treatment for diabetes and obesity.


Assuntos
Glucose/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Receptores da Calcitonina/agonistas , Animais , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Ingestão de Alimentos/efeitos dos fármacos , Hiperglicemia/tratamento farmacológico , Hiperglicemia/metabolismo , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Ratos
14.
Obesity (Silver Spring) ; 28(5): 942-952, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32237211

RESUMO

OBJECTIVE: Intermittent (INT) access to a high-fat diet (HFD) can induce excessive-intake phenotypes in rodents. This study hypothesized that impaired satiation responses contribute to elevated intake in an INT-HFD access model. METHODS: First, this study characterized the intake and meal patterns of female rats that were subjected to an INT HFD in which a 45% HFD was presented for 20 hours every fourth day. To examine nutrient-induced satiation, rats received intragastric infusions of saline or Ensure Plus prior to darkness-onset food access. A similar design was used to examine sensitivity to the satiating effect of amylin. This study then examined whether an INT HFD influences amylin-induced c-Fos in feeding-relevant brain areas. RESULTS: Upon INT HFD access, rats consumed meals of larger size. The anorexic response to intragastric Ensure infusion and exogenous amylin treatment was blunted in INT rats on both chow-only and INT-HFD days of the diet regimen, compared with chow-maintained and continuous-HFD rats. An INT HFD did not influence amylin-induced c-Fos in the area postrema, nucleus of the solitary tract, and lateral parabrachial nucleus. CONCLUSIONS: Impaired satiation responses, mediated in part by reduced sensitivity to amylin, may explain the elevated intake observed upon INT HFD access and may play a role in disorders of INT overconsumption, including binge eating.


Assuntos
Dieta Hiperlipídica/métodos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Nutrientes/metabolismo , Animais , Comportamento Alimentar/fisiologia , Feminino , Ratos , Ratos Endogâmicos WF
15.
Sci Rep ; 10(1): 3751, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111883

RESUMO

A major characteristic of Alzheimer's disease (AD) is the accumulation of misfolded amyloid-ß (Aß) peptide. Several studies linked AD with type 2 diabetes due to similarities between Aß and human amylin. This study investigates the effect of amylin and pramlintide on Aß pathogenesis and the predisposing molecular mechanism(s) behind the observed effects in TgSwDI mouse, a cerebral amyloid angiopathy (CAA) and AD model. Our findings showed that thirty days of intraperitoneal injection with amylin or pramlintide increased Aß burden in mice brains. Mechanistic studies revealed both peptides altered the amyloidogenic pathway and increased Aß production by modulating amyloid precursor protein (APP) and γ-secretase levels in lipid rafts. In addition, both peptides increased levels of B4GALNT1 enzyme and GM1 ganglioside, and only pramlintide increased the level of GM2 ganglioside. Increased levels of GM1 and GM2 gangliosides play an important role in regulating amyloidogenic pathway proteins in lipid rafts. Increased brain Aß burden by amylin and pramlintide was associated with synaptic loss, apoptosis, and microglia activation. In conclusion, our findings showed amylin or pramlintide increase Aß levels and related pathology in TgSwDI mice brains, and suggest that increased amylin levels or the therapeutic use of pramlintide could increase the risk of AD.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/farmacologia , Microdomínios da Membrana/metabolismo , Processamento de Proteína Pós-Traducional , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/genética , Precursor de Proteína beta-Amiloide/genética , Animais , Angiopatia Amiloide Cerebral/genética , Angiopatia Amiloide Cerebral/metabolismo , Angiopatia Amiloide Cerebral/patologia , Gangliosídeo G(M1)/genética , Gangliosídeo G(M1)/metabolismo , Gangliosídeo G(M2)/genética , Gangliosídeo G(M2)/metabolismo , Microdomínios da Membrana/genética , Microdomínios da Membrana/patologia , Camundongos , Camundongos Transgênicos , N-Acetilgalactosaminiltransferases/genética , N-Acetilgalactosaminiltransferases/metabolismo
16.
Soft Matter ; 16(12): 3143-3153, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32159545

RESUMO

Human amylin is an intrinsically disordered protein believed to have a central role in Type-II diabetes mellitus (T2DM). The formation of intermediate oligomers is a seminal event in the eventual self-assembled fibril structures of amylin. However, the recent experimental investigations have shown the presence of different self-assembled (oligomers, protofilaments, and fibrils) and aggregated structures (amorphous aggregates) of amylin formed during its aggregation. Here, we show that amylin under diffusion-limited conditions leads to fractal self-assembly. The pH and solvent sensitive fractal self-assemblies of amylin were observed using an optical microscope. Confocal microscopy and scanning electron microscopy (SEM) with energy dispersion X-ray analysis (EDAX) were used to confirm the fractal self-assembly of amylin in water and PBS buffer, respectively. The fractal characteristics of the self-assemblies and the aggregates formed during the aggregation of amylin under different pH conditions were investigated using laser light scattering. The hydropathy and the docking study indicated the interactions between the anisotropically distributed hydrophobic residues and polar/ionic residues on the solvent-accessible surface of the protein as the crucial interaction hot-spots for driving the self-assembly and aggregation of human amylin. The simultaneous presence of various self-assemblies of human amylin was observed through different microscopy techniques. The present study may help in designing different fractal-like nanomaterials with potential applications in drug delivery, sensing, and tissue engineering.


Assuntos
Amiloide/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Agregados Proteicos , Amiloide/ultraestrutura , Fractais , Humanos , Interações Hidrofóbicas e Hidrofílicas , Polipeptídeo Amiloide das Ilhotas Pancreáticas/ultraestrutura , Modelos Moleculares , Conformação Proteica
17.
Curr Pharm Des ; 26(12): 1345-1355, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32188374

RESUMO

Type II Diabetes (T2D) is a major risk factor for Alzheimer's Disease (AD). These two diseases share several pathological features, including amyloid accumulation, inflammation, oxidative stress, cell death and cognitive decline. The metabolic hormone amylin and amyloid-beta are both amyloids known to self-aggregate in T2D and AD, respectively, and are thought to be the main pathogenic entities in their respective diseases. Furthermore, studies suggest amylin's ability to seed amyloid-beta aggregation, the activation of common signaling cascades in the pancreas and the brain, and the ability of amyloid beta to signal through amylin receptors (AMYR), at least in vitro. However, paradoxically, non-aggregating forms of amylin such as pramlintide are given to treat T2D and functional and neuroprotective benefits of amylin and pramlintide administration have been reported in AD transgenic mice. These paradoxical results beget a deeper study of the complex nature of amylin's signaling through the several AMYR subtypes and other receptors associated with amylin effects to be able to fully understand its potential role in mediating AD development and/or prevention. The goal of this review is to provide such critical insight to begin to elucidate how the complex nature of this hormone's signaling may explain its equally complex relationship with T2D and mechanisms of AD pathogenesis.


Assuntos
Doença de Alzheimer , Diabetes Mellitus Tipo 2 , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Animais , Polipeptídeo Amiloide das Ilhotas Pancreáticas , Camundongos , Camundongos Transgênicos
18.
J Nat Med ; 74(3): 579-583, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32219646

RESUMO

The number of patients with Alzheimer's disease (AD) and type 2 diabetes (T2D) is increasing rapidly, and thus more research has been focused on the relationship between these two age-related chronic diseases. According to the amyloid hypothesis, prevention of the aggregation of amyloid ß (Aß) and human islet amyloid polypeptide (hIAPP) is a promising strategy for AD and T2D. In this study, thioflavin-T assay and transmission electron microscopy were performed to evaluate the inhibitory effect of three phenylpropanoids isolated from Lycopus lucidus-schizotenuin A and lycopic acids A and B-on both Aß and hIAPP fibrillization. All tested compounds exhibited similarly strong inhibitory activity toward amyloid aggregation. These results suggested that catechol moieties play important roles in the inhibition of amyloid plaque formation.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/antagonistas & inibidores , Diabetes Mellitus Tipo 2/tratamento farmacológico , Polipeptídeo Amiloide das Ilhotas Pancreáticas/antagonistas & inibidores , Lycopus/química , Catecóis/metabolismo , Humanos , Extratos Vegetais/farmacologia
19.
Sci Rep ; 10(1): 5120, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198463

RESUMO

More than 20 unique diseases such as diabetes, Alzheimer's disease, Parkinson's disease are caused by the abnormal aggregations of pathogenic proteins such as amylin, ß-amyloid (Aß), and α-synuclein. All pathogenic proteins differ from each other in biological function, primary sequences, and morphologies; however, the proteins are toxic when aggregated. Here, we investigated the cellular toxicity of pathogenic or non-pathogenic protein aggregates. In this study, six proteins were selected and they were incubated at acid pH and high temperature. The aggregation kinetic and cellular toxicity of protein species with time were characterized. Three non-pathogenic proteins, bovine serum albumin (BSA), catalase, and pepsin at pH 2 and 65 °C were stable in protein structure and non-toxic at a lower concentration of 1 mg/mL. They formed aggregates at a higher concentration of 20 mg/mL with time and they induced the toxicity in short incubation time points, 10 min and 20 min only and they became non-toxic after 30 min. Other three pathogenic proteins, lysozyme, superoxide dismutase (SOD), and insulin, also produced the aggregates with time and they caused cytotoxicity at both 1 mg/mL and 20 mg/mL after 10 min. TEM images and DSC analysis demonstrated that fibrils or aggregates at 1 mg/mL induced cellular toxicity due to low thermal stability. In DSC data, fibrils or aggregates of pathogenic proteins had low thermal transition compared to fresh samples. The results provide useful information to understand the aggregation and cellular toxicity of pathogenic and non-pathogenic proteins.


Assuntos
Catalase/metabolismo , Insulina/metabolismo , Muramidase/metabolismo , Pepsina A/metabolismo , Agregados Proteicos/fisiologia , Agregação Patológica de Proteínas/patologia , Soroalbumina Bovina/metabolismo , Superóxido Dismutase/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Linhagem Celular , Diabetes Mellitus/genética , Diabetes Mellitus/patologia , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Modelos Moleculares , Doença de Parkinson/genética , Doença de Parkinson/patologia , Estrutura Secundária de Proteína/fisiologia , alfa-Sinucleína/metabolismo
20.
Diabetes ; 69(6): 1110-1125, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32152204

RESUMO

Amylin, a pancreatic hormone and neuropeptide, acts principally in the hindbrain to decrease food intake and has recently been shown to act as a neurotrophic factor to control the development of area postrema → nucleus of the solitary tract and arcuate hypothalamic nucleus → paraventricular nucleus axonal fiber outgrowth. Amylin is also able to activate ERK signaling specifically in POMC neurons independently of leptin. For investigation of the physiological role of amylin signaling in POMC neurons, the core component of the amylin receptor, calcitonin receptor (CTR), was depleted from POMC neurons using an inducible mouse model. The loss of CTR in POMC neurons leads to increased body weight gain, increased adiposity, and glucose intolerance in male knockout mice, characterized by decreased energy expenditure (EE) and decreased expression of uncoupling protein 1 (UCP1) in brown adipose tissue. Furthermore, a decreased spontaneous locomotor activity and absent thermogenic reaction to the application of the amylin receptor agonist were observed in male and female mice. Together, these results show a significant physiological impact of amylin/calcitonin signaling in CTR-POMC neurons on energy metabolism and demonstrate the need for sex-specific approaches in obesity research and potentially treatment.


Assuntos
Metabolismo Energético/fisiologia , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Neurônios/fisiologia , Pró-Opiomelanocortina/metabolismo , Receptores da Calcitonina/metabolismo , Receptores de Polipeptídeo Amiloide de Ilhotas Pancreáticas/metabolismo , Tecido Adiposo Marrom , Animais , Masculino , Camundongos , Atividade Motora , Receptores de Polipeptídeo Amiloide de Ilhotas Pancreáticas/genética , Transdução de Sinais/fisiologia , alfa-MSH/genética , alfa-MSH/metabolismo
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