Publications by authors named "Laura Morelli"

64 Publications

Liver X Receptor Activation with an Intranasal Polymer Therapeutic Prevents Cognitive Decline without Altering Lipid Levels.

ACS Nano 2021 Mar 5. Epub 2021 Mar 5.

Instituto de Ciencias Biomédicas, Facultad de Ciencias Médicas, Universidad Católica de Cuyo, Av. José Ignacio de la Roza 1516, Rivadavia, 5400, San Juan, Argentina.

The progressive accumulation of amyloid-beta (Aβ) in specific areas of the brain is a common prelude to late-onset of Alzheimer's disease (AD). Although activation of liver X receptors (LXR) with agonists decreases Aβ levels and ameliorates contextual memory deficit, concomitant hypercholesterolemia/hypertriglyceridemia limits their clinical application. DMHCA (,-dimethyl-3β-hydroxycholenamide) is an LXR partial agonist that, despite inducing the expression of apolipoprotein E (main responsible of Aβ drainage from the brain) without increasing cholesterol/triglyceride levels, shows nil activity because of a low solubility and inability to cross the blood brain barrier. Herein, we describe a polymer therapeutic for the delivery of DMHCA. The covalent incorporation of DMHCA into a PEG-dendritic scaffold via carboxylate esters produces an amphiphilic copolymer that efficiently self-assembles into nanometric micelles that exert a biological effect in primary cultures of the central nervous system (CNS) and experimental animals using the intranasal route. After CNS biodistribution and effective doses of DMHCA micelles were determined in nontransgenic mice, a transgenic AD-like mouse model of cerebral amyloidosis was treated with the micelles for 21 days. The benefits of the treatment included prevention of memory deterioration and a significant reduction of hippocampal Aβ oligomers without affecting plasma lipid levels. These results represent a proof of principle for further clinical developments of DMHCA delivery systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.0c09159DOI Listing
March 2021

Dementia in Latin America: Paving the way toward a regional action plan.

Authors:
Mario Alfredo Parra Sandra Baez Lucas Sedeño Cecilia Gonzalez Campo Hernando Santamaría-García Ivan Aprahamian Paulo Hf Bertolucci Julian Bustin Maria Aparecida Camargos Bicalho Carlos Cano-Gutierrez Paulo Caramelli Marcia L F Chaves Patricia Cogram Bárbara Costa Beber Felipe A Court Leonardo Cruz de Souza Nilton Custodio Andres Damian Myriam de la Cruz Roberta Diehl Rodriguez Sonia Maria Dozzi Brucki Lais Fajersztajn Gonzalo A Farías Fernanda G De Felice Raffaele Ferrari Fabricio Ferreira de Oliveira Sergio T Ferreira Ceres Ferretti Marcio Luiz Figueredo Balthazar Norberto Anizio Ferreira Frota Patricio Fuentes Adolfo M García Patricia J Garcia Fábio Henrique de Gobbi Porto Lissette Duque Peñailillo Henry Willy Engler Irene Maier Ignacio F Mata Christian Gonzalez-Billault Oscar L Lopez Laura Morelli Ricardo Nitrini Yakeel T Quiroz Alejandra Guerrero Barragan David Huepe Fabricio Joao Pio Claudia Kimie Suemoto Renata Kochhann Silvia Kochen Fiona Kumfor Serggio Lanata Bruce Miller Leticia Lessa Mansur Mirna Lie Hosogi Patricia Lillo Jorge Llibre Guerra David Lira Francisco Lopera Adelina Comas José Alberto Avila-Funes Ana Luisa Sosa Claudia Ramos Elisa de Paula França Resende Heather M Snyder Ioannis Tarnanas Jenifer Yokoyama Juan Llibre Juan Felipe Cardona Kate Possin Kenneth S Kosik Rosa Montesinos Sebastian Moguilner Patricia Cristina Lourdes Solis Renata Eloah de Lucena Ferretti-Rebustini Jeronimo Martin Ramirez Diana Matallana Lingani Mbakile-Mahlanza Alyne Mendonça Marques Ton Ronnielly Melo Tavares Eliane C Miotto Graciela Muniz-Terrera Luis Arnoldo Muñoz-Nevárez David Orozco Maira Okada de Oliveira Olivier Piguet Maritza Pintado Caipa Stefanie Danielle Piña Escudero Lucas Porcello Schilling André Luiz Rodrigues Palmeira Mônica Sanches Yassuda Jose Manuel Santacruz-Escudero Rodrigo Bernardo Serafim Jerusa Smid Andrea Slachevsky Cecilia Serrano Marcio Soto-Añari Leonel Tadao Takada Lea Tenenholz Grinberg Antonio Lucio Teixeira Maira Tonidandel Barbosa Dominic Trépel Agustin Ibanez

Alzheimers Dement 2021 02 20;17(2):295-313. Epub 2020 Nov 20.

Cognitive Neuroscience Center (CNC) Buenos Aires, Argentina; Universidad Autonoma del Caribe, Barranquilla, Colombia; Global Brain Health Institute (GBHI), US, Universidad de San Andres, CONICET, Universidad Autonoma del Caribe, Universidad Adolfo Ibanez, UCSF, USA.

Across Latin American and Caribbean countries (LACs), the fight against dementia faces pressing challenges, such as heterogeneity, diversity, political instability, and socioeconomic disparities. These can be addressed more effectively in a collaborative setting that fosters open exchange of knowledge. In this work, the Latin American and Caribbean Consortium on Dementia (LAC-CD) proposes an agenda for integration to deliver a Knowledge to Action Framework (KtAF). First, we summarize evidence-based strategies (epidemiology, genetics, biomarkers, clinical trials, nonpharmacological interventions, networking, and translational research) and align them to current global strategies to translate regional knowledge into transformative actions. Then we characterize key sources of complexity (genetic isolates, admixture in populations, environmental factors, and barriers to effective interventions), map them to the above challenges, and provide the basic mosaics of knowledge toward a KtAF. Finally, we describe strategies supporting the knowledge creation stage that underpins the translational impact of KtAF.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/alz.12202DOI Listing
February 2021

Setup and Validation of a Reliable Docking Protocol for the Development of Neuroprotective Agents by Targeting the Sigma-1 Receptor (S1R).

Int J Mol Sci 2020 Oct 18;21(20). Epub 2020 Oct 18.

Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, V.le Taramelli 12, 27100 Pavia, Italy.

Sigma-1 receptor (S1R) is a promising molecular target for the development of novel effective therapies against neurodegenerative diseases. To speed up the discovery of new S1R modulators, herein we report the development of a reliable in silico protocol suitable to predict the affinity of small molecules against S1R. The docking method was validated by comparing the computational calculated values of a test set of new aryl-aminoalkyl-ketone with experimental determined binding affinity. The druggability profile of the new compounds, with particular reference to the ability to cross the blood-brain barrier (BBB) was further predicted in silico. Moreover, the selectivity over Sigma-2 receptor (S2R) and N-methyl-D-aspartate (NMDA) receptor, another protein involved in neurodegeneration, was evaluated. 1-([1,1'-biphenyl]-4-yl)-4-(piperidin-1-yl)butan-1-one () performed as the best compound and was further investigated for acetylcholinesterase (AchE) inhibitor activity and determination of antioxidant activity mediated by aquaporins (AQPs). With a good affinity against both S1R and NMDA receptor, good selectivity over S2R and favorable BBB penetration potential together with its AChE inhibitory activity and its ability to exert antioxidant effects through modulation of AQPs, represents a viable candidate for further development as a neuroprotective agent.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21207708DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589021PMC
October 2020

Mitochondrial Supercomplexes: Physiological Organization and Dysregulation in Age-Related Neurodegenerative Disorders.

Front Endocrinol (Lausanne) 2020 11;11:600. Epub 2020 Sep 11.

Laboratory of Brain Aging and Neurodegeneration-Fundación Instituto Leloir-IIBBA-CONICET, Buenos Aires, Argentina.

Several studies suggest that the assembly of mitochondrial respiratory complexes into structures known as supercomplexes (SCs) may increase the efficiency of the electron transport chain, reducing the rate of production of reactive oxygen species. Therefore, the study of the (dis)assembly of SCs may be relevant for the understanding of mitochondrial dysfunction reported in brain aging and major neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). Here we briefly reviewed the biogenesis and structural properties of SCs, the impact of mtDNA mutations and mitochondrial dynamics on SCs assembly, the role of lipids on stabilization of SCs and the methodological limitations for the study of SCs. More specifically, we summarized what is known about mitochondrial dysfunction and SCs organization and activity in aging, AD and PD. We focused on the critical variables to take into account when postmortem tissues are used to study the (dis)assembly of SCs. Since few works have been performed to study SCs in AD and PD, the impact of SCs dysfunction on the alteration of brain energetics in these diseases remains poorly understood. The convergence of future progress in the study of SCs structure at high resolution and the refinement of animal models of AD and PD, as well as the use of iPSC-based and somatic cell-derived neurons, will be critical in understanding the biological relevance of the structural remodeling of SCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fendo.2020.00600DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7518391PMC
September 2020

Contactless Capacitive Electrocardiography Using Hybrid Flexible Printed Electrodes.

Sensors (Basel) 2020 Sep 10;20(18). Epub 2020 Sep 10.

École de Technologie Supérieure (ÉTS), Université du Québec, Montréal, QC H3C 1K3, Canada.

Traditional capacitive electrocardiogram (cECG) electrodes suffer from limited patient comfort, difficulty of disinfection and low signal-to-noise ratio in addition to the challenge of integrating them in wearables. A novel hybrid flexible cECG electrode was developed that offers high versatility in the integration method, is well suited for large-scale manufacturing, is easy to disinfect in clinical settings and exhibits better performance over a comparable rigid contactless electrode. The novel flexible electrode meets the frequency requirement for clinically important QRS complex detection (0.67-5 Hz) and its performance is improved over rigid contactless electrode across all measured metrics as it maintains lower cut-off frequency, higher source capacitance and higher pass-band gain when characterized over a wide spectrum of patient morphologies. The results presented in this article suggest that the novel flexible electrode could be used in a medical device for cECG acquisition and medical diagnosis. The novel design proves also to be less sensitive to motion than a reference rigid electrode. We therefore anticipate it can represent an important step towards improving the repeatability of cECG methods while requiring less post-processing. This would help making cECG a viable method for remote cardiac health monitoring.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s20185156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7570869PMC
September 2020

NADPH oxidase and mitochondria are relevant sources of superoxide anion in the oxinflammatory response of macrophages exposed to airborne particulate matter.

Ecotoxicol Environ Saf 2020 Dec 24;205:111186. Epub 2020 Aug 24.

Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Química Analítica y Fisicoquímica, Cátedra de Química General e Inorgánica, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Bioquímica y Medicina Molecular (IBIMOL), Facultad de Farmacia y Bioquímica, Argentina. Electronic address:

Exposure to ambient air particulate matter (PM) is associated with increased cardiorespiratory morbidity and mortality. In this context, alveolar macrophages exhibit proinflammatory and oxidative responses as a result of the clearance of particles, thus contributing to lung injury. However, the mechanisms linking these pathways are not completely clarified. Therefore, the oxinflammation phenomenon was studied in RAW 264.7 macrophages exposed to Residual Oil Fly Ash (ROFA), a PM surrogate rich in transition metals. While cell viability was not compromised under the experimental conditions, a proinflammatory phenotype was observed in cells incubated with ROFA 100 μg/mL, characterized by increased levels of TNF-α and NO production, together with PM uptake. This inflammatory response seems to precede alterations in redox metabolism, characterized by augmented levels of HO, diminished GSH/GSSG ratio, and increased SOD activity. This scenario resulted in increased oxidative damage to phospholipids. Moreover, alterations in mitochondrial respiration were observed following ROFA incubation, such as diminished coupling efficiency and spare respiratory capacity, together with augmented proton leak. These findings were accompanied by a decrease in mitochondrial membrane potential. Finally, NADPH oxidase (NOX) and mitochondria were identified as the main sources of superoxide anion () in our model. These results indicate that PM exposure induces direct activation of macrophages, leading to inflammation and increased reactive oxygen species production through NOX and mitochondria, which impairs antioxidant defense and may cause mitochondrial dysfunction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ecoenv.2020.111186DOI Listing
December 2020

Glycans Meet Sphingolipids: Structure-Based Design of Glycan Containing Analogues of a Sphingosine Kinase Inhibitor.

ACS Med Chem Lett 2020 May 30;11(5):913-920. Epub 2020 Mar 30.

Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, FI, Italy).

Sphingosine 1-phosphate (S1P) is a bioactive lipid mediator associated with diverse homeostatic and signaling roles. Enhanced biosynthesis of S1P, mediated by the sphingosine kinase isozymes (SK1 and SK2), is implicated in several pathophysiological conditions and diseases, including skeletal muscle fibrosis, inflammation, multiple sclerosis, and cancer. Therefore, therapeutic approaches that control S1P production have focused on the development of SK1/2 inhibitors. In this framework, we designed a series of natural monosaccharide-based compounds to enhance anchoring of the known SK1 inhibitor PF-543 at the polar head of the substrate-binding channel. Herein, we describe the structure-based design and synthesis of new glycan-containing PF-543 analogues and we demonstrate their efficiency in a TGFβ1-induced pro-fibrotic assay.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsmedchemlett.9b00665DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7236250PMC
May 2020

Gold nanoparticles morphology does not affect the multivalent presentation and antibody recognition of Group A Streptococcus synthetic oligorhamnans.

Bioorg Chem 2020 06 3;99:103815. Epub 2020 Apr 3.

Department of Chemistry and CRC Materiali Polimerici (LaMPo), University of Milan, Via C. Golgi 19, 20133 Milan, Italy. Electronic address:

The development of novel delivery systems capable of enhancing the antibody binding affinity and immunoactivity of short length saccharide antigens is at the forefront of modern medicine. In this regard, gold nanoparticles (AuNPs) raised great interest as promising nano-vaccine platform, as they do not interfere with the desired immune response and their surface can be easily functionalized, enabling the antigen multivalent presentation. In addition, the nanoparticles morphology can have a great impact on their biological properties. Gram-positive Group A Streptococcus (GAS) is a bacterium responsible for many infections and represents a priority healthcare concern, but a universal vaccine is still unavailable. Since all the GAS strains have a cell wall characterized by a common polyrhamnose backbone, this can be employed as alternative antigen to develop an anti-GAS vaccine. Herein, we present the synthesis of two oligorhamnoside fragments and their corresponding oligorhamnoside-AuNPs, designed with two different morphologies. By competitive ELISA we assessed that both symmetric and anisotropic oligorhamnan nanoparticles inhibit the binding of specific polyclonal serum much better than the unconjugated oligosaccharides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bioorg.2020.103815DOI Listing
June 2020

Exploring calixarene-based clusters for efficient functional presentation of Streptococcus pneumoniae saccharides.

Bioorg Chem 2019 12 19;93:103305. Epub 2019 Sep 19.

Department of Medical Biotechnology and Translational Medicine, University of Milan, Via Saldini 50, 20133 Milano, Italy. Electronic address:

Calixarenes are promising scaffolds for an efficient clustered exposition of multiple saccharide antigenic units. Herein we report the synthesis and biological evaluation of a calix[6]arene functionalized with six copies of the trisaccharide repeating unit of Streptococcus pneumoniae (SP) serotype 19F. This system has demonstrated its ability to efficiently inhibit the binding between the native 19F capsular polysaccharide and anti-19F antibodies, despite a low number of exposed saccharide antigens, well mimicking the epitope presentations in the polysaccharide. The calix[6]arene mobile scaffold has been selected for functionalization with SP 19F repeating unit after a preliminary screening of four model glycocalixarenes, functionalized with N-acetyl mannosamine, and differing in the valency and/or conformational properties. This work is a step forward towards the development of new fully synthetic calixarenes comprising small carbohydrate antigens as potential carbohydrate-based vaccine scaffolds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bioorg.2019.103305DOI Listing
December 2019

Perturbed mitochondria-ER contacts in live neurons that model the amyloid pathology of Alzheimer's disease.

J Cell Sci 2019 10 22;132(20). Epub 2019 Oct 22.

Laboratory of Brain Aging and Neurodegeneration, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE Ciudad Autónoma de Buenos Aires, Argentina

The use of fixed fibroblasts from familial and sporadic Alzheimer's disease patients has previously indicated an upregulation of mitochondria-ER contacts (MERCs) as a hallmark of Alzheimer's disease. Despite its potential significance, the relevance of these results is limited because they were not extended to live neurons. Here we performed a dynamic analysis of MERCs in hippocampal neurons from McGill-R-Thy1-APP transgenic rats, a model of Alzheimer's disease-like amyloid pathology. Live FRET imaging of neurons from transgenic rats revealed perturbed 'lipid-MERCs' (gap width <10 nm), while 'Ca-MERCs' (10-20 nm gap width) were unchanged. TEM showed no significant differences in the lipid-MERCs:total MERCs or lipid-MERCs:mitochondria ratios; however, the average length of lipid-MERCs was significantly decreased in neurons from transgenic rats as compared to controls. In accordance with FRET results, untargeted lipidomics showed significant decreases in levels of 12 lipids and bioenergetic analysis revealed respiratory dysfunction of mitochondria from transgenic rats. Thus, our results reveal changes in MERC structures coupled with impaired mitochondrial functions in Alzheimer's disease-related neurons.This article has an associated First Person interview with the first author of the paper.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1242/jcs.229906DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6826005PMC
October 2019

Monocyte glycolysis determines CD8+ T cell functionality in human Chagas disease.

JCI Insight 2019 09 19;4(18). Epub 2019 Sep 19.

Universidad Nacional de Córdoba, Facultad de Ciencias Químicas, Departamento de Bioquímica Clínica, Córdoba, Argentina.

Chagas disease is a lifelong pathology resulting from Trypanosoma cruzi infection. It represents one of the most frequent causes of heart failure and sudden death in Latin America. Herein, we provide evidence that aerobic glycolytic pathway activation in monocytes drives nitric oxide (NO) production, triggering tyrosine nitration (TN) on CD8+ T cells and dysfunction in patients with chronic Chagas disease. Monocytes from patients exhibited a higher frequency of hypoxia-inducible factor 1α and increased expression of its target genes/proteins. Nonclassical monocytes are expanded in patients' peripheral blood and represent an important source of NO. Monocytes entail CD8+ T cell surface nitration because both the frequency of nonclassical monocytes and that of NO-producing monocytes positively correlated with the percentage of TN+ lymphocytes. Inhibition of glycolysis in in vitro-infected peripheral blood mononuclear cells decreased the inflammatory properties of monocytes/macrophages, diminishing the frequency of IL-1β- and NO-producing cells. In agreement, glycolysis inhibition reduced the percentage of TN+CD8+ T cells, improving their functionality. Altogether, these results clearly show that glycolysis governs oxidative stress on monocytes and modulates monocyte-T cell interplay in human chronic Chagas disease. Understanding the pathological immune mechanisms that sustain an inflammatory environment in human pathology is key to designing improved therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/jci.insight.123490DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6795286PMC
September 2019

Endoplasmic Reticulum Stress in Tauopathies: Contrasting Human Brain Pathology with Cellular and Animal Models.

J Alzheimers Dis 2019 ;68(2):439-458

Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina.

The accumulation and spreading of protein tau in the human brain are major features of neurodegenerative disorders known as tauopathies. In addition to several subcellular abnormalities, tau aggregation within neurons seems capable of triggering endoplasmic reticulum (ER) stress and the consequent unfolded protein response (UPR). In metazoans, full activation of a complex ER-UPR network may restore proteostasis and ER function or, if stress cannot be solved, commit cells to apoptosis. Due to these alternative outcomes (survival or death), the pharmacological manipulation of ER-UPR has become the focus of potential therapies in many human diseases, including tauopathies. Here we update and analyze the experimental data from human brain, cellular, and animal models linking tau accumulation and ER-UPR. We further discuss mechanistic aspects and put the ER-UPR into perspective as a possible therapeutic target in this group of diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3233/JAD-181021DOI Listing
July 2020

Transethnic meta-analysis of rare coding variants in PLCG2, ABI3, and TREM2 supports their general contribution to Alzheimer's disease.

Transl Psychiatry 2019 01 31;9(1):55. Epub 2019 Jan 31.

Division of Neurogenetics and Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University of Cologne, 50937, Cologne, Germany.

Rare coding variants in TREM2, PLCG2, and ABI3 were recently associated with the susceptibility to Alzheimer's disease (AD) in Caucasians. Frequencies and AD-associated effects of variants differ across ethnicities. To start filling the gap on AD genetics in South America and assess the impact of these variants across ethnicity, we studied these variants in Argentinian population in association with ancestry. TREM2 (rs143332484 and rs75932628), PLCG2 (rs72824905), and ABI3 (rs616338) were genotyped in 419 AD cases and 486 controls. Meta-analysis with European population was performed. Ancestry was estimated from genome-wide genotyping results. All variants show similar frequencies and odds ratios to those previously reported. Their association with AD reach statistical significance by meta-analysis. Although the Argentinian population is an admixture, variant carriers presented mainly Caucasian ancestry. Rare coding variants in TREM2, PLCG2, and ABI3 also modulate susceptibility to AD in populations from Argentina, and they may have a European heritage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41398-019-0394-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6355764PMC
January 2019

Synthesis and biological evaluation of a trisaccharide repeating unit derivative of Streptococcus pneumoniae 19A capsular polysaccharide.

Bioorg Med Chem 2018 11 19;26(21):5682-5690. Epub 2018 Oct 19.

Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, Via Saldini 50, 20133 Milano, Italy. Electronic address:

Streptococcus pneumoniae (SP) is a common human pathogen associated with a broad spectrum of diseases and it is still a leading cause of mortality and morbidity worldwide, especially in children. Moreover, SP is increasingly associated with drug resistance. Vaccination against the pathogen may thus represent an important strategy to overcome its threats to human health. In this context, revealing the molecular determinants of SP immunoreactivity may be relevant for the development of novel molecules with therapeutic perspectives as vaccine components. Serogroup 19 comprises the immune-cross reactive types 19F, 19A, 19B and 19C and it accounts for a high percentage of invasive pneumococcal diseases, mainly caused by serotypes 19F and 19A. Herein, we report the synthesis and biological evaluation of an aminopropyl derivative of the trisaccharide repeating unit of SP 19A. We compare two different synthetic strategies, based on different disconnections between the three monosaccharides which make up the final trisaccharide, to define the best approach for the preparation of the trisaccharide. Synthetic accessibility to the trisaccharide repeating unit lays the basis for the development of more complex biopolymer as well as saccharide conjugates. We also evaluate the binding affinity of the trisaccharide for anti-19A and anti-19F sera and discuss the relationship between the chemical properties of the trisaccharide unit and biological activity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bmc.2018.10.016DOI Listing
November 2018

Platelets Bioenergetics Screening Reflects the Impact of Brain Aβ Plaque Accumulation in a Rat Model of Alzheimer.

Neurochem Res 2019 Jun 24;44(6):1375-1386. Epub 2018 Oct 24.

Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE, Ciudad Autónoma de Buenos Aires, Argentina.

Alzheimer's disease (AD) is associated to depressed brain energy supply and impaired cortical and hippocampal synaptic function. It was previously reported in McGill-R-Thy1-APP transgenic (Tg(+/+)) rats that Aβ deposition per se is sufficient to cause abnormalities in glucose metabolism and neuronal connectivity. These data support the utility of this animal model as a platform for the search of novel AD biomarkers based on bioenergetic status. Recently, it has been proposed that energy dysfunction can be dynamically tested in platelets (PLTs) of nonhuman primates. PLTs are good candidates to find peripheral biomarkers for AD because they may reflect in periphery the bioenergetics deficits and the inflammatory and oxidative stress processes taking place in AD brain. In the present study, we carried out a PLTs bioenergetics screening in advanced-age (12-14 months old) control (WT) and Tg(+/+) rats. Results indicated that thrombin-activated PLTs of Tg(+/+) rats showed a significantly lower respiratory rate, as compared to that measured in WT animals, when challenged with the same dose of FCCP (an uncoupler of oxidative phosphorylation). In summary, our results provide original evidence that PLTs bioenergetic profiling may reflect brain bioenergetics dysfunction mediated by Aβ plaque accumulation. Further studies on human PLTs from control and AD patients are required to validate the usefulness of PLTs bioenergetics as a novel blood-based biomarker for AD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11064-018-2657-xDOI Listing
June 2019

Chronic Hippocampal Expression of Notch Intracellular Domain Induces Vascular Thickening, Reduces Glucose Availability, and Exacerbates Spatial Memory Deficits in a Rat Model of Early Alzheimer.

Mol Neurobiol 2018 Nov 26;55(11):8637-8650. Epub 2018 Mar 26.

Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE, Ciudad Autónoma de Buenos Aires, Argentina.

The specific roles of Notch in progressive adulthood neurodegenerative disorders have begun to be unraveled in recent years. A number of independent studies have shown significant increases of Notch expression in brains from patients at later stages of sporadic Alzheimer's disease (AD). However, the impact of Notch canonical signaling activation in the pathophysiology of AD is still elusive. To further investigate this issue, 2-month-old wild-type (WT) and hemizygous McGill-R-Thy1-APP rats (Tg(+/-)) were injected in CA1 with lentiviral particles (LVP) expressing the transcriptionally active fragment of Notch, known as Notch Intracellular Domain (NICD), (LVP-NICD), or control lentivirus particles (LVP-C). The Tg(+/-) rat model captures presymptomatic aspects of the AD pathology, including intraneuronal amyloid beta (Aβ) accumulation and early cognitive deficits. Seven months after LVP administration, Morris water maze test was performed, and brains isolated for biochemical and histological analysis. Our results showed a learning impairment and a worsening of spatial memory in LVP-NICD- as compared to LVP-C-injected Tg(+/-) rats. In addition, immuno histochemistry, ELISA multiplex, Western blot, RT-qPCR, and H-NMR spectrometry of cerebrospinal fluid (CSF) indicated that chronic expression of NICD promoted hippocampal vessel thickening with accumulation of Aβ in brain microvasculature, alteration of blood-brain barrier (BBB) permeability, and a decrease of CSF glucose levels. These findings suggest that, in the presence of early Aβ pathology, expression of NICD may contribute to the development of microvascular abnormalities, altering glucose transport at the BBB with impact on early decline of spatial learning and memory.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12035-018-1002-3DOI Listing
November 2018

Combined Chemical Synthesis and Tailored Enzymatic Elongation Provide Fully Synthetic and Conjugation-Ready Neisseria meningitidis Serogroup X Vaccine Antigens.

ACS Chem Biol 2018 04 1;13(4):984-994. Epub 2018 Mar 1.

GSK , Via Fiorentina 1 , 53100 Siena , Italy.

Studies on the polymerization mode of Neisseria meningitidis serogroup X capsular polymerase CsxA recently identified a truncated construct that can be immobilized and used for length controlled on-column production of oligosaccharides. Here, we combined the use of a synthetic acceptor bearing an appendix for carrier protein conjugation and the on-column process to a novel chemo-enzymatic strategy. After protein coupling of the size optimized oligosaccharide produced by the one-pot elongation procedure, we obtained a more homogeneous glycoconjugate compared to the one previously described starting from the natural polysaccharide. Mice immunized with the conjugated fully synthetic oligomer elicited functional antibodies comparable to controls immunized with the current benchmark MenX glycoconjugates prepared from the natural capsule polymer or from fragments of it enzymatically elongated. This pathogen-free technology allows the fast total in vitro construction of predefined bacterial polysaccharide fragments. Compared to conventional synthetic protocols, the procedure is more expeditious and drastically reduces the number of purification steps to achieve the oligomers. Furthermore, the presence of a linker for conjugation in the synthetic acceptor minimizes manipulations on the enzymatically produced glycan prior to protein conjugation. This approach enriches the methods for fast construction of complex bacterial carbohydrates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acschembio.7b01057DOI Listing
April 2018

Amyloid-β42 clearance and neuroprotection mediated by X-box binding protein 1 signaling decline with aging in the Drosophila brain.

Neurobiol Aging 2017 12 24;60:57-70. Epub 2017 Aug 24.

Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, Buenos Aires, Argentina; Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina. Electronic address:

The unfolded protein response (UPR) may be pathogenically related to Alzheimer's disease. Yet, the effects of chronic amyloid-β42 (Aβ42) accumulation and UPR activation upon neurotoxicity remain unclear. Here, we show that neuronal Aβ42 expression in Drosophila activated the inositol-requiring protein-1/X-box binding protein 1 (XBP1) UPR branch before the onset of behavioral impairment and persisted with aging. Early upregulation of hsc3/BiP, a target of XBP1 and activating transcription factor 6 pathways, was also sustained in old animals. Downregulation of XBP1 enhanced neurotoxicity and the accumulation of Aβ42 and polyubiquitinated proteins. Consistently, overexpression of spliced XBP1 reduced Aβ42 and improved geotaxis in old flies. The activation of protein kinase RNA-like endoplasmic reticulum (ER) kinase contributed to the age-dependent geotaxis deficit. Spliced XBP1 gene targets ER degradation-enhancing mannosidase-like protein 1, ER degradation-enhancing mannosidase-like protein 2, and HRD1 were elevated in 5-day-old Aβ42-expressing flies as compared to controls but not in 18-day-old flies. Our results indicate that inositol-requiring protein-1/XBP1 activation is neuroprotective and enhances Aβ42 clearance. They also suggest that such response becomes inefficient with aging.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neurobiolaging.2017.08.012DOI Listing
December 2017

An Injectable System for Local and Sustained Release of Antimicrobial Agents in the Periodontal Pocket.

Macromol Biosci 2017 08 2;17(8). Epub 2017 May 2.

Tensive S.r.l., Via Timavo 34, 20124, Milano, Italy.

Periodontitis treatments usually require local administration of antimicrobial drugs with the aim to reduce the bacterial load inside the periodontal pocket. Effective pharmaceutical treatments may require sustained local drug release for several days in the site of interest. Currently available solutions are still not able to fulfill the clinical need for high-quality treatments, mainly in terms of release profiles and patients' comfort. This work aims to fill this gap through the development of an in situ gelling system, capable to achieve controlled and sustained release of antimicrobial agents for medium-to-long-term treatments. The system is composed of micrometer-sized β-cyclodextrin-based hydrogel (bCD-Jef-MPs), featured by a strong hydrophilic character, suspended in a synthetic block-co-polymer solution (Poloxamer 407), which is capable to undergo rapid thermally induced sol-gel phase transition at body temperature. The chemical structure of bCD-Jef-MPs was confirmed by cross-correlating data from Fourier transform infrared (FTIR) spectroscopy, swelling test, and degradation kinetics. The thermally induced sol-gel phase transition is demonstrated by rheometric tests. The effectiveness of the described system to achieve sustained release of antimicrobial agents is demonstrated in vitro, using chlorhexidine digluconate as a drug model. The results achieved in this work disclose the potential of the mentioned system in effectively treating periodontitis lesions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mabi.201700103DOI Listing
August 2017

A Novel Genetic Screen Identifies Modifiers of Age-Dependent Amyloid β Toxicity in the Brain.

Front Aging Neurosci 2017 14;9:61. Epub 2017 Mar 14.

Laboratorio de Amiloidosis y Neurodegeneración, Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires, Argentina.

The accumulation of amyloid β peptide (Aβ) in the brain of Alzheimer's disease (AD) patients begins many years before clinical onset. Such process has been proposed to be pathogenic through the toxicity of Aβ soluble oligomers leading to synaptic dysfunction, phospho-tau aggregation and neuronal loss. Yet, a massive accumulation of Aβ can be found in approximately 30% of aged individuals with preserved cognitive function. Therefore, within the frame of the "amyloid hypothesis", compensatory mechanisms and/or additional neurotoxic or protective factors need to be considered and investigated. Here we describe a modifier genetic screen in designed to identify genes that modulate toxicity of Aβ42 in the CNS. The expression of Aβ42 led to its accumulation in the brain and a moderate impairment of negative geotaxis at 18 days post-eclosion (d.p.e) as compared with genetic or parental controls. These flies were mated with a collection of lines carrying chromosomal deletions and negative geotaxis was assessed at 5 and 18 d.p.e. Our screen is the first to take into account all of the following features, relevant to sporadic AD: (1) pan-neuronal expression of wild-type Aβ42; (2) a quantifiable complex behavior; (3) Aβ neurotoxicity associated with progressive accumulation of the peptide; and (4) improvement or worsening of climbing ability only evident in aged animals. One hundred and ninety-nine deficiency (Df) lines accounting for ~6300 genes were analyzed. Six lines, including the deletion of 52 genes with human orthologs, significantly modified Aβ42 neurotoxicity in 18-day-old flies. So far, we have validated and identified as a strong candidate (whose human orthologs are and , respectively) by using RNAi or mutant hemizygous lines. encodes proline-rich protein PRCC (ppPRCC) of unknown function associated with papillary renal cell carcinoma. encodes 4-hydroxyphenylpyruvate dioxygenase (HPPD), a key enzyme in tyrosine degradation whose Df causes autosomal recessive Tyrosinemia type 3, characterized by mental retardation. Interestingly, lines with a partial Df of ortholog showed increased intraneuronal accumulation of Aβ42 that coincided with geotaxis impairment. These previously undetected modifiers of Aβ42 neurotoxicity in warrant further study to validate their possible role and significance in the pathogenesis of sporadic AD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnagi.2017.00061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5349081PMC
March 2017

Worsening of memory deficit induced by energy-dense diet in a rat model of early-Alzheimer's disease is associated to neurotoxic Aβ species and independent of neuroinflammation.

Biochim Biophys Acta Mol Basis Dis 2017 03 27;1863(3):731-743. Epub 2016 Dec 27.

Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir, IIBBA-CONICET, Argentina. Electronic address:

Diet is a modifiable risk factor for Alzheimer's disease (AD), but the mechanisms linking alterations in peripheral metabolism and cognition remain unclear. Since it is especially difficult to study long-term effects of high-energy diet in individuals at risk for AD, we addressed this question by using the McGill-R-Thy1-APP transgenic rat model (Tg(+/-)) that mimics presymptomatic AD. Wild-type and Tg(+/-) rats were exposed during 6months to a standard diet or a Western diet (WD), high in saturated fat and sugar. Results from peripheral and hippocampal biochemical analysis and in situ respirometry showed that WD induced a metabolic syndrome and decreased presynaptic bioenergetic parameters without alterations in hippocampal insulin signaling or lipid composition. Cognitive tests, ELISA multiplex, Western blot, immunohistochemistry and RT-qPCR indicated that WD worsened cognition in Tg(+/-) rats, increased hippocampal levels of monomeric Aβ isoforms and oligomeric species, promoted deposits of N-Terminal pyroglutamate-Aβ (AβN3(pE)) in CA1 pyramidal neurons and interneurons, decreased transcript levels of genes involved in neuroprotective pathways such as Sirtuin-1 and increased nitrated proteins. Our results support the concept that in the presence of early Aβ pathology, diet-induced metabolic dysfunctions may contribute as a "second hit" to impair cognition. Noteworthy, such effect is not mediated by higher microglia activation or disruption of blood brain barrier. However, it may be attributed to increased amyloidogenic processing of amyloid precursor protein, generation of AβN3(pE) and dysregulation of pathways governed by Sirtuin-1. This evidence reinforces the implementation of prophylactic interventions in individuals at risk for AD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbadis.2016.12.014DOI Listing
March 2017

Synaptosomal bioenergetic defects are associated with cognitive impairment in a transgenic rat model of early Alzheimer's disease.

J Cereb Blood Flow Metab 2017 01 9;37(1):69-84. Epub 2015 Nov 9.

Laboratory of Amyloidosis and Neurodegeneration, Fundación Instituto Leloir-IIBBA-CONICET, Buenos Aires, Argentina

Synaptic bioenergetic deficiencies may be associated with early Alzheimer's disease (AD). To explore this concept, we assessed pre-synaptic mitochondrial function in hemizygous (+/-)TgMcGill-R-Thy1-APP rats. The low burden of Aβ and the wide array of behavioral and cognitive impairments described in 6-month-old hemizygous TgMcGill-R-Thy1-APP rats (Tg(+/-)) support their use to investigate synaptic bioenergetics deficiencies described in subjects with early Alzheimer's disease (AD). In this report, we show that pre-synaptic mitochondria from Tg(+/-) rats evidence a decreased respiratory control ratio and spare respiratory capacity associated with deficits in complex I enzymatic activity. Cognitive impairments were prevented and bioenergetic deficits partially reversed when Tg(+/-) rats were fed a nutritionally complete diet from weaning to 6-month-old supplemented with pyrroloquinoline quinone, a mitochondrial biogenesis stimulator with antioxidant and neuroprotective effects. These results provide evidence that, as described in AD brain and not proven in Tg mice models with AD-like phenotype, the mitochondrial bioenergetic capacity of synaptosomes is not conserved in the Tg(+/-) rats. This animal model may be suitable for understanding the basic biochemical mechanisms involved in early AD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0271678X15615132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5363729PMC
January 2017

Correction: DMT1 iron uptake in the PNS: bridging the gap between injury and regeneration.

Metallomics 2015 Dec;7(12):1612

Departamento de Química Biológica, Facultad de Farmacia y Bíoquímica, Universidad de Buenos Aires, Instituto de Química y Físicoquímica Biológica (IQUIFIB), UBA-CONICET, Buenos Aires, Argentina.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c5mt90048dDOI Listing
December 2015

DMT1 iron uptake in the PNS: bridging the gap between injury and regeneration.

Metallomics 2015 Oct 11;7(10):1381-9. Epub 2015 Sep 11.

Departamento de Química Biológica, Facultad de Farmacia y Bíoquímica, Universidad de Buenos Aires, Instituto de Química y Físicoquímica Biológica (IQUIFIB), UBA-CONICET, Buenos Aires, Argentina.

Previous studies by our group demonstrated the key role of iron in Schwann cell maturation through an increase in cAMP, PKA activation and CREB phosphorylation. These studies opened the door to further research on non-transferrin-bound iron uptake, which revealed the presence of DMT1 mRNA all along SC progeny, hinting at a constitutive role of DMT1 in ensuring the provision of iron in the PNS. In light of these previous results, the present work evaluates the participation of DMT1 in the remyelination process following a demyelinating lesion promoted by sciatic nerve crush--a reversible model of Wallerian degeneration. DMT1 was observed to colocalize with a SC marker S100β at all survival times analyzed. In turn, the assessment of DMT1 mRNA expression exhibited an increase 7 days post-injury, while DMT1 protein levels showed an increase 14 days after crush at the lesion site and distal stump; finally, an increase in iron levels became evident as from 14 days post-injury, in parallel with DMT1 values. To sum up, the present work unveils the role of DMT1 in mediating the neuroregenerative action of iron.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c5mt00156kDOI Listing
October 2015

Activation of Hsp90 Enzymatic Activity and Conformational Dynamics through Rationally Designed Allosteric Ligands.

Chemistry 2015 Sep 18;21(39):13598-608. Epub 2015 Aug 18.

Istituto di Chimica del Riconoscimento Molecolare, CNR via Mario Bianco, 9, 20131, Milan (Italy).

Hsp90 is a molecular chaperone of pivotal importance for multiple cell pathways. ATP-regulated internal dynamics are critical for its function and current pharmacological approaches block the chaperone with ATP-competitive inhibitors. Herein, a general approach to perturb Hsp90 through design of new allosteric ligands aimed at modulating its functional dynamics is proposed. Based on the characterization of a first set of 2-phenylbenzofurans showing stimulatory effects on Hsp90 ATPase and conformational dynamics, new ligands were developed that activate Hsp90 by targeting an allosteric site, located 65 Å from the active site. Specifically, analysis of protein responses to first-generation activators was exploited to guide the design of novel derivatives with improved ability to stimulate ATP hydrolysis. The molecules' effects on Hsp90 enzymatic, conformational, co-chaperone and client-binding properties were characterized through biochemical, biophysical and cellular approaches. These designed probes act as allosteric activators of the chaperone and affect the viability of cancer cell lines for which proper functioning of Hsp90 is necessary.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.201502211DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921052PMC
September 2015

Identification of PSEN2 mutation p.N141I in Argentine pedigrees with early-onset familial Alzheimer's disease.

Neurobiol Aging 2015 Oct 15;36(10):2674-7.e1. Epub 2015 Jun 15.

Laboratorio de Bioquímica Molecular, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina; Centro de Neuropsiquiatria y Neurología de la Conducta (CENECON), Departamento Ciencias Fisiológicas UAII, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina. Electronic address:

Presenilin 2 gene (PSEN2) mutations account for <5% of all early-onset familial Alzheimer's disease (EOFAD) cases and only 13 have strong evidence for pathogenicity. We aimed to investigate the presence of PSEN2 mutation p.N141I and characterize the clinical phenotypes in 2 Argentine pedigrees (AR2 and AR3) with clinical symptoms of EOFAD. Detailed clinical assessments and genetic screening for PSEN2 and APOE genes were carried out in 19 individuals of AR2 and AR3 families. The p.N141I mutation was identified in all affected subjects and was associated with prominent early onset, rapidly progressive dementia, neurologic, and behavioral symptoms. AR2 and AR3 families share the same Volga German ancestry as all the families reported presenting this mutation. To our knowledge, this is the first report of PSEN2 mutation p.N141I in Argentina and even more, in South America. Our contribution increases the total number of described families carrying this mutation and help to improve the characterization of clinical phenotype in EOFAD associated to PSEN2 mutations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neurobiolaging.2015.06.011DOI Listing
October 2015

Anti-Group B Streptococcus Glycan-Conjugate Vaccines Using Pilus Protein GBS80 As Carrier and Antigen: Comparing Lysine and Tyrosine-directed Conjugation.

ACS Chem Biol 2015 Jul 6;10(7):1737-46. Epub 2015 May 6.

‡Novartis Institutes for BioMedical Research, 100 Technology Square, Cambridge, Massachusetts 02139, United States.

Gram-positive Streptococcus agalactiae or group B Streptococcus (GBS) is a leading cause of invasive infections in pregnant women, newborns, and elderly people. Vaccination of pregnant women represents the best strategy for prevention of neonatal disease, and GBS polysaccharide-based conjugate vaccines are currently under clinical testing. The potential of GBS pilus proteins selected by genome-based reverse vaccinology as protective antigens for anti-streptococcal vaccines has also been demonstrated. Dressing pilus proteins with surface glycan antigens could be an attractive approach to extend vaccine coverage. We have recently developed an efficient method for tyrosine-directed ligation of large glycans to proteins via copper-free azide-alkyne [3 + 2] cycloaddition. This method enables targeting of predetermined sites of the protein, ensuring that protein epitopes are preserved prior to glycan coupling and a higher consistency in glycoconjugate batches. Herein, we compared conjugates of the GBS type II polysaccharide (PSII) and the GBS80 pilus protein obtained by classic lysine random conjugation and by the recently developed tyrosine-directed ligation. PSII conjugated to CRM197, a carrier protein used for vaccines in the market, was used as a control. We found that the constructs made from PSII and GBS80 were able to elicit murine antibodies recognizing individually the glycan and protein epitopes on the bacterial surface. The generated antibodies were efficacious in mediating opsonophagocytic killing of strains expressing exclusively PSII or GBS80 proteins. The two glycoconjugates were also effective in protecting newborn mice against GBS infection following vaccination of the dams. Altogether, these results demonstrated that polysaccharide-conjugated GBS80 pilus protein functions as a carrier comparably to CRM197, while maintaining its properties of protective protein antigen. Glycoconjugation and reverse vaccinology can, therefore, be combined to design vaccines with broad coverage. This approach opens a path to a new generation of vaccines. Tyrosine-ligation allows creation of more homogeneous vaccines, correlation of the immune response to defined connectivity points, and fine-tuning of the conjugation site in glycan-protein conjugates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acschembio.5b00247DOI Listing
July 2015

Synthesis and immunological evaluation of protein conjugates of Neisseria meningitidis X capsular polysaccharide fragments.

Beilstein J Org Chem 2014 13;10:2367-76. Epub 2014 Oct 13.

Dipartimento di Chimica and ISTM-CNR, Universita degli Studi di Milano, via Golgi 19, I-20133 Milano, Italy.

A vaccine to prevent infections from the emerging Neisseria meningitidis X (MenX) is becoming an urgent issue. Recently MenX capsular polysaccharide (CPS) fragments conjugated to CRM197 as carrier protein have been confirmed at preclinical stage as promising candidates for vaccine development. However, more insights about the minimal epitope required for the immunological activity of MenX CPS are needed. We report herein the chemical conjugation of fully synthetic MenX CPS oligomers (monomer, dimer, and trimer) to CRM197. Moreover, improvements in some crucial steps leading to the synthesis of MenX CPS fragments are described. Following immunization with the obtained neoglycoconjugates, the conjugated trimer was demonstrated as the minimal fragment possessing immunogenic activity, even though significantly lower than a pentadecamer obtained from the native polymer and conjugated to the same protein. This finding suggests that oligomers longer than three repeating units are possibly needed to mimic the activity of the native polysaccharide.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3762/bjoc.10.247DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4222376PMC
November 2014

Longitudinal analysis of the behavioral phenotype in a novel transgenic rat model of early stages of Alzheimer's disease.

Front Behav Neurosci 2014 16;8:321. Epub 2014 Sep 16.

Laboratorio de Amiloidosis y Neurodegeneración, Instituto de Investigaciones Bioquímicas de Buenos Aires, Fundación Instituto Leloir, CONICET Ciudad Autónoma de Buenos Aires, Argentina.

Intraneuronal accumulation of amyloid β (iAβ) has been linked to mild cognitive impairment that may precede Alzheimer's disease (AD) onset. This neuropathological trait was recently mimicked in a novel animal model of AD, the hemizygous transgenic McGill-R-Thy1-APP (Tg(+/-)) rat. The characterization of the behavioral phenotypes in this animal model could provide a baseline of efficacy for earlier therapeutic interventions. The aim of the present study was to undertake a longitudinal study of Aβ accumulation and a comprehensive behavioral evaluation of this transgenic rat model. We assessed exploratory activity, anxiety-related behaviors, recognition memory, working memory, spatial learning and reference memory at 3, 6, and 12 months of age. In parallel, we measured Aβ by ELISA, Western blots and semiquantitative immunohistochemistry in hippocampal samples. SDS-soluble Aβ peptide accumulated at low levels (~9 pg/mg) without differences among ages. However, Western blots showed SDS-resistant Aβ oligomers (~30 kDa) at 6 and 12 months, but not at 3 months. When compared to wild-type (WT), male Tg(+/-) rats exhibited a spatial reference memory deficit in the Morris Water Maze (MWM) as early as 3 months of age, which persisted at 6 and 12 months. In addition, Tg(+/-) rats displayed a working memory impairment in the Y-maze and higher anxiety levels in the Open Field (OF) at 6 and 12 months of age, but not at 3 months. Exploratory activity in the OF was similar to that of WT at all-time points. Spatial learning in the MWM and the recognition memory, as assessed by the Novel Object Recognition Test, were unimpaired at any time point. The data from the present study demonstrate that the hemizygous transgenic McGill-R-Thy1-APP rat has a wide array of behavioral and cognitive impairments from young adulthood to middle-age. The low Aβ burden and early emotional and cognitive deficits in this transgenic rat model supports its potential use for drug discovery purposes in early AD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnbeh.2014.00321DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4165352PMC
October 2014

Structure of the type IX group B Streptococcus capsular polysaccharide and its evolutionary relationship with types V and VII.

J Biol Chem 2014 Aug 2;289(34):23437-48. Epub 2014 Jul 2.

From Novartis Vaccines Research, 53100 Siena, Italy.

The Group B Streptococcus capsular polysaccharide type IX was isolated and purified, and the structure of its repeating unit was determined. Type IX capsule → 4)[NeupNAc-α-(2 → 3)-Galp-β-(1 → 4)-GlcpNAc-β-(1 → 6)]-β-GlcpNAc-(1 → 4)-β-Galp-(1 → 4)-β-Glcp-(1 → appears most similar to types VII and V, although it contains two GlcpNAc residues. Genetic analysis identified differences in cpsM, cpsO, and cpsI gene sequences as responsible for the differentiation between the three capsular polysaccharide types, leading us to hypothesize that type V emerged from a recombination event in a type IX background.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.M114.567974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4156066PMC
August 2014