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Erming Wang, Haihao Zhu, Xiaofan Wang, Adam Gower, Max Wallack, Jan Krzysztof Blusztajn, Neil Kowall, Wei Qiao Qiu
Our recent study has demonstrated that peripheral amylin treatment reduces the amyloid pathology in the brain of Alzheimer's disease (AD) mouse models, and improves their learning and memory. We hypothesized that the beneficial effects of amylin for AD was beyond reducing the amyloids in the brain, and have now directly tested the actions of amylin on other aspects of AD pathogenesis, especially neuroinflammation. A 10-week course of peripheral amylin treatment significantly reduced levels of cerebral inflammation markers, Cd68 and Iba1, in amyloid precursor protein (APP) transgenic mice...
November 28, 2016: Journal of Alzheimer's Disease: JAD
Jeffrey Friedman
Leptin is an adipose tissue hormone that functions as an afferent signal in a negative feedback loop that maintains homeostatic control of adipose tissue mass. This endocrine system thus serves a critical evolutionary function by protecting individuals from the risks associated with being too thin (starvation) or too obese (predation and temperature dysregulation). Mutations in leptin or its receptor cause massive obesity in mice and humans, and leptin can effectively treat obesity in leptin-deficient patients...
December 1, 2016: Journal of Clinical Investigation
Jacqueline F Aitken, Kerry M Loomes, Isabel Riba-Garcia, Richard D Unwin, Gordana Prijic, Ashley S Phillips, Anthony R J Phillips, Donghai Wu, Sally D Poppitt, Ke Ding, Perdita E Barran, Andrew W Dowsey, Garth J S Cooper
Pancreatic islet β-cells secrete the hormones insulin and amylin, and defective β-cell function plays a central role in the pathogenesis of type-2 diabetes (T2D). Human amylin (hA, also termed hIAPP) misfolds and forms amyloid aggregates whereas orthologous mouse amylin does neither. Furthermore, hA elicits apoptosis in cultured β-cells and β-cell death in ex-vivo islets. In addition, hA-transgenic mice that selectively express hA in their β-cells, manifest β-cell apoptosis and progressive islet damage that leads to diabetes closely resembling that in patients with T2D...
November 16, 2016: Biochemical and Biophysical Research Communications
Sidharth Mahapatra, Lihua Ying, Lawrence Steinman, David Cornfield
No abstract text is available yet for this article.
December 2016: Critical Care Medicine
Manju Chandran
Diabetes be it type 1 or type 2 is associated with an increased risk of fragility fractures. The mechanisms underlying this increased risk are just being elucidated. Anti-diabetes medications are crucial for maintaining glucose control and for preventing micro- and macrovascular complications in diabetes. However, they may modulate fracture risk in diabetes in different ways. Thiazolidinediones have demonstrated an unfavorable effect on the skeleton, while metformin and sulfonylureas may have a neutral if not beneficial effect on bone...
November 4, 2016: Calcified Tissue International
Giuseppe Caruso, Donatella A Distefano, Paolo Parlascino, Claudia G Fresta, Giuseppe Lazzarino, Susan M Lunte, Vincenzo G Nicoletti
Human amylin (hA1-37) is a polypeptide hormone secreted in conjunction with insulin from the pancreatic β-cells involved in the pathogenesis of type 2 diabetes mellitus (T2DM). The shorter fragment hA17-29 than full-length peptide is capable to form amyloids "in vitro". Here, we monitored the time course of hA17-29 β-amyloid fibril and oligomer formation [without and with copper(II)], cellular toxicity of different amyloid aggregates, and involvement of specific receptors (receptor for advanced glycation end-products, RAGE; low-affinity nerve growth factor receptor, p75-NGFR) in aggregate toxicity...
November 1, 2016: Molecular and Cellular Biochemistry
Istvan Horvath, Pernilla Wittung-Stafshede
In type-2 diabetes (T2D) and Parkinson's disease (PD), polypeptide assembly into amyloid fibers plays central roles: in PD, α-synuclein (aS) forms amyloids and in T2D, amylin [islet amyloid polypeptide (IAPP)] forms amyloids. Using a combination of biophysical methods in vitro we have investigated whether aS, IAPP, and unprocessed IAPP, pro-IAPP, polypeptides can cross-react. Whereas IAPP forms amyloids within minutes, aS takes many hours to assemble into amyloids and pro-IAPP aggregates even slower under the same conditions...
October 17, 2016: Proceedings of the National Academy of Sciences of the United States of America
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 13, 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 N 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. Compared with diet-resistant (DR) neonates, DIO neonates have impaired leptin-dependent arcuate (ARC) neuropeptide Y/agouti-related peptide (NPY/AgRP) and α-melanocyte-stimulating hormone (α-MSH; from proopiomelanocortin (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...
December 1, 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
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