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Nan Zhang, Shengchang Yang, Chang Wang, Jianghua Zhang, Lifang Huo, Yiru Cheng, Chuan Wang, Zhanfeng Jia, Leiming Ren, Lin Kang, Wei Zhang
Alzheimer's disease (AD) and type II diabetes mellitus (DM2) are the most common aging-related diseases and are characterized by β-amyloid and amylin accumulation, respectively. Multiple studies have indicated a strong correlation between these two diseases. Amylin oligomerization in the brain appears to be a novel risk factor for developing AD. Although amylin aggregation has been demonstrated to induce cytotoxicity in neurons through altering Ca(2+) homeostasis, the underlying mechanisms have not been fully explored...
October 12, 2016: Neuropharmacology
Luiza C S Erthal, Adriana F Marques, Fábio C L Almeida, Gustavo L M Melo, Camila M Carvalho, Leonardo C Palmieri, Katia M S Cabral, Giselle N Fontes, Luís Maurício T R Lima
The secretory granule of the pancreatic β-cells is a zinc-rich environment copopulated with the hormones amylin and insulin. The human amylin is shown to interact with zinc ions with major contribution from the single histidine residue, which is absent in amylin from other species such as cat, rhesus and rodents. We report here the interaction of murine amylin with zinc ions in vitro. The self-assembly of murine amylin is tightly regulated by zinc and pH. Ion mobility mass spectrometry revealed zinc interaction with monomers and oligomers...
November 2016: Biophysical Chemistry
Claudia G Liberini, Tito Borner, Christina N Boyle, Thomas A Lutz
OBJECTIVE: Adult neurogenesis in the subgranular zone and subventricular zone is generally accepted, but its existence in other brain areas is still controversial. Circumventricular organs, such as the area postrema (AP) have recently been described as potential neurogenic niches in the adult brain. The AP is the major site of action of the satiating hormone amylin. Amylin has been shown to promote the formation of neuronal projections originating from the AP in neonatal rodents but the role of amylin in adult neurogenesis remains unknown...
October 2016: Molecular Metabolism
Dayana Cabral da Silva, Giselle N Fontes, Luiza C S Erthal, Luís Maurício T R Lima
Amylin is a pancreatic peptide hormone co-secreted along with insulin by the β-cells. It is found in amyloid deposits in both type 2 diabetic individuals and elder non-diabetic. The triple proline amylinomimetic compound (25,28,29-Pro-human amylin) named pramlintide was designed aiming to solve the solubility and amyloid characteristics of human amylin. We have found by using ion mobility spectrometry-based mass spectrometry that pramlintide is able to assembly into multimers. Pramlintide formed amyloid fibrils in vitro in a pH-dependent kinetic process within a few hours, as followed by thioflavin T, quantification of soluble peptide and further characterized by transmission electron microscopy, atomic force microscopy and X-ray diffraction...
September 20, 2016: Biophysical Chemistry
Yoav Atsmon-Raz, Yifat Miller
It has been suggested that the connection between amyloidogenic diseases is related to the interactions between aggregates of amyloids, which are related to type 2 diabetes and Parkinson's disease. Herein, we illustrate the interactions between amylin oligomers and non-amyloid β component (NAC) oligomers. Using molecular dynamics simulations and statistical calculations, we studied the mechanisms through which NAC oligomers interact with amylin oligomers to form NAC-amylin hetero-oligomers. Our simulations have shown that there are more than one possible pathways, which form the NAC-amylin hetero-oligomers...
October 7, 2016: Journal of Physical Chemistry. B
Abba J Kastin, Weihong Pan
Pertinent to pandemic obesity, the discovery of endogenous peptides that affect the ingestion of food has led to the question of how these ingestive peptides exert their actions in the brain. Whereas peripheral sources provide a ready reserve, the availability of ingestive peptides to their central nervous system targets can be regulated by the blood-brain barrier (BBB). Some of the peptides/polypeptides are transported by saturable mechanisms from blood to brain. Examples include leptin, insulin, mahogany, and pancreatic polypeptide...
September 20, 2016: CNS & Neurological Disorders Drug Targets
Ingunn Narverud, Mari C W Myhrstad, Karl-Heinz Herzig, Toni Karhu, Tuva B Dahl, Bente Halvorsen, Stine M Ulven, Kirsten B Holven
Peptides released from the small intestine and colon regulate short-term food intake by suppressing appetite and inducing satiety. Intake of marine omega-3 (n-3) fatty acids (FAs) from fish and fish oils is associated with beneficial health effects, whereas the relation between intake of the vegetable n-3 fatty acid α-linolenic acid and diseases is less clear. The aim of the present study was to investigate the postprandial effects of a single high-fat meal enriched with vegetable n-3 or a combination of vegetable and marine n-3 FAs with their different unsaturated fatty acid composition on intestinal peptide release and the adipose tissue...
2016: Frontiers in Nutrition
Miranda D Johnson, Sebastien G Bouret, Ambrose A Dunn-Meynell, Christina Neuner Boyle, Thomas A Lutz, Barry E Levin
Selectively bred diet-induced obese (DIO) rats become obese on a high fat diet and are leptin resistant before becoming obese. As compared to diet-resistant (DR) neonates, DIO neonates have impaired leptin-dependent arcuate (ARC) neuropeptide Y/agouti-related peptide (NPY/AgRP) and α-melanocyte-stimulating hormone (αMSH; from pro-opiomelanocortin (POMC) neurons) axon outgrowth to the paraventricular nucleus (PVN). Using phosphorylation of STAT3 (pSTAT3) as a surrogate, we show that reduced DIO ARC leptin signaling develops by postnatal day 7 (P7) and is reduced within POMC, but not NPY/AgRP neurons...
September 14, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Louise Larsen, Christelle Le Foll, Ambrose A Dunn-Meynell, Barry E Levin
Rats selectively bred to develop diet-induced obesity (DIO) have an early onset reduction in the sensitivity of their ventromedial hypothalamic nucleus (VMN) neurons to leptin as compared to diet-resistant (DR) rats. This reduced sensitivity includes decreased leptin receptor (Lepr-b) mRNA expression, leptin receptor binding, leptin-induced phosphorylation of STAT3 (pSTAT3) and impaired leptin excitation (LepE) of VMN neurons. When administered exogenously, the pancreatic peptide, amylin, acts synergistically to reduce food intake and body weight in obese, leptin resistant DIO rats by increasing VMN leptin signaling, likely by stimulation of microglia IL-6 which acts on its receptor to increase leptin-induced pSTAT3...
August 17, 2016: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Antonio Magrì, Diego La Mendola, Vincenzo Giuseppe Nicoletti, Giuseppe Pappalardo, Enrico Rizzarelli
Type-2 diabetes (T2D) is considered to be a potential threat on a global level. Recently, T2D has been listed as a misfolding disease, such as Alzheimer's and Parkinson's diseases. Human islet amyloid polypeptide (hIAPP) is a molecule cosecreted in pancreatic β cells and represents the main constituent of an aggregated amyloid found in individuals affected by T2D. The trace-element serum level is significantly influenced during the development of diabetes. In particular, the dys-homeostasis of Cu(2+) ions may adversely affect the course of the disease...
September 5, 2016: Chemistry: a European Journal
Amy G Wong, Daniel P Raleigh
Amyloid deposition underlies a broad range of diseases including multiple neurodegenerative diseases, systemic amyloidosis and type-2 diabetes. Amyloid sensitive dyes, particularly thioflavin-T, are widely used to detect ex-vivo amyloid deposits, to monitor amyloid formation in vitro and to follow the kinetics of amyloid self-assembly. We show that the dye SYPRO-orange binds to amyloid fibrils formed by human amylin, the polypeptide responsible for islet amyloid formation in type-2 diabetes. No fluorescence enhancement is observed in the presence of pre-fibrillar species or in the presence of non-amyloidogenic rat amylin...
October 2016: Protein Science: a Publication of the Protein Society
Sang-Min Lee, Debbie L Hay, Augen A Pioszak
No abstract text is available yet for this article.
July 29, 2016: Journal of Biological Chemistry
Anna Gavrieli, Christos S Mantzoros
Excess energy intake, without a compensatory increase of energy expenditure, leads to obesity. Several molecules are involved in energy homeostasis regulation and new ones are being discovered constantly. Appetite regulating hormones such as ghrelin, peptide tyrosine-tyrosine and amylin or incretins such as the gastric inhibitory polypeptide have been studied extensively while other molecules such as fibroblast growth factor 21, chemerin, irisin, secreted frizzle-related protein-4, total bile acids, and heme oxygenase-1 have been linked to energy homeostasis regulation more recently and the specific role of each one of them has not been fully elucidated...
September 2016: Endocrinology and Metabolism
Joseph J Gingell, John Simms, James Barwell, David R Poyner, Harriet A Watkins, Augen A Pioszak, Patrick M Sexton, Debbie L Hay
G protein-coupled receptors are allosteric proteins that control transmission of external signals to regulate cellular response. Although agonist binding promotes canonical G protein signalling transmitted through conformational changes, G protein-coupled receptors also interact with other proteins. These include other G protein-coupled receptors, other receptors and channels, regulatory proteins and receptor-modifying proteins, notably receptor activity-modifying proteins (RAMPs). RAMPs have at least 11 G protein-coupled receptor partners, including many class B G protein-coupled receptors...
2016: Cell Discovery
Paul Velander, Ling Wu, W Keith Ray, Richard F Helm, Bin Xu
Amyloid formation of the 37-residue amylin is involved in the pathogenesis of type 2 diabetes and, potentially, diabetes-induced neurological deficits. Numerous flavonoids exhibit inhibitory effects against amylin amyloidosis, but the mechanisms of inhibition remain unclear. Screening a library of natural compounds uncovered a potent lead compound, the flavone baicalein. Baicalein inhibits amylin amyloid formation and reduces amylin-induced cytotoxicity. Analogue analyses demonstrated, for the first time, key roles of the vicinal hydroxyl groups on the A-ring...
August 9, 2016: Biochemistry
Vered Wineman-Fisher, Yifat Miller
Amylin is an endocrine hormone and is a member of the family of amyloid peptides and proteins that emerge as potential scaffolds by self-assembly processes. Zn(2+) ions can bind to amylin peptides to form self-assembled Zn(2+)-amylin oligomers. In the current work the binding sites of Zn(2+) ions in the self-assembled amylin oligomers at various concentrations of zinc have been investigated. Our results yield two conclusions. First, in the absence of Zn(2+) ions polymorphic states (i.e. various classes of amylin oligomers) are obtained, but when Zn(2+) ions bind to amylin peptides to form Zn(2+)-amylin oligomers, the polymorphism is decreased, i...
August 3, 2016: Physical Chemistry Chemical Physics: PCCP
Nina Schultz, Elin Byman, Malin Fex, Malin Wennström
Amylin, a pancreatic β-cell-derived peptide hormone, forms inclusions in brain microvessels of patients with dementia who have been diagnosed with type 2 diabetes and Alzheimer's disease. The cellular localization of these inclusions and the consequences thereof are not yet known. Using immunohistochemical staining of hippocampus and parahippocampal cortex from patients with Alzheimer's disease and non-demented controls, we show that amylin cell inclusions are found in pericytes. The number of amylin cell inclusions did not differ between patients with Alzheimer's disease and controls, but amylin-containing pericytes displayed nuclear changes associated with cell death and reduced expression of the pericyte marker neuron-glial antigen 2...
June 28, 2016: Journal of Cerebral Blood Flow and Metabolism
S Martínez-Herrero, A Martínez
Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are 2 biologically active peptides produced by the same gene, ADM, with ubiquitous distribution and many physiological functions. Adrenomedullin is composed of 52 amino acids, has an internal molecular ring composed by 6 amino acids and a disulfide bond, and shares structural similarities with calcitonin gene-related peptide, amylin, and intermedin. The AM receptor consists of a 7-transmembrane domain protein called calcitonin receptor-like receptor in combination with a single transmembrane domain protein known as receptor activity-modifying protein...
July 2016: Domestic Animal Endocrinology
Sanghamitra Singh, Saurabh Trikha, Anjali Sarkar, Aleksandar M Jeremic
Toxic human amylin (hA) oligomers and aggregates are implicated in the pathogenesis of type 2 diabetes mellitus (T2DM). Although recent studies demonstrated a causal connection between hA uptake and toxicity in pancreatic cells, the mechanism of amylin's clearance following its internalization and its relationship to toxicity is yet to be determined, and hence was investigated here. Using pancreatic rat insulinoma β-cells and human islets as model systems, we show that hA, following its internalization, first accumulates in the cytosol followed by its translocation into nucleus, and to a lesser extent lysosomes, keeping the net cytosolic amylin content low...
September 1, 2016: Biochemical Journal
Miao Liu, Nirmal Verma, Xiaoli Peng, Sarah Srodulski, Andrew Morris, Martin Chow, Louis B Hersh, Jing Chen, Haining Zhu, Mihai G Netea, Kenneth B Margulies, Sanda Despa, Florin Despa
Hypersecretion of amylin is common in individuals with prediabetes, causes amylin deposition and proteotoxicity in pancreatic islets, and contributes to the development of type 2 diabetes. Recent studies also identified amylin deposits in failing hearts from patients with obesity or type 2 diabetes and demonstrated that hyperamylinemia accelerates the development of heart dysfunction in rats expressing human amylin in pancreatic β-cells (HIP rats). To further determine the impact of hyperamylinemia on cardiac myocytes, we investigated human myocardium, compared diabetic HIP rats with diabetic rats expressing endogenous (nonamyloidogenic) rat amylin, studied normal mice injected with aggregated human amylin, and developed in vitro cell models...
September 2016: Diabetes
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