Aggregate formation prevents dTDP-43 neurotoxicity in the Drosophila melanogaster eye

TDP-43 inclusions are an important histopathological feature in various neurodegenerative disorders, including Amyotrophic Lateral Sclerosis and Fronto-Temporal Lobar Degeneration. However, the relation of these inclusions with the pathogenesis of the disease is still unclear. In fact, the inclusions could be toxic themselves, induce loss of function by sequestering TDP-43 or a combination of both. Previously, we have developed a cellular model of aggregation using the TDP-43 Q/N rich amino acid sequence 331-369 repeated 12 times (12xQ/N) and have shown that these cellular inclusions are capable of sequestering the endogenous TDP-43 both in non-neuronal and neuronal cells. We have tested this model in vivo in the Drosophila melanogaster eye. The eye structure develops normally in the absence of dTDP-43, a fact previously seen in knock out fly strains. We show here that expression of EGFP 12xQ/N does not alter the structure of the eye. In contrast, TBPH overexpression is neurotoxic and causes necrosis and loss of function of the eye. More important, the neurotoxicity of TBPH can be abolished by its incorporation to the insoluble aggregates induced by EGFP 12xQ/N. This data indicates that aggregation is not toxic per se and instead has a protective role, modulating the functional TBPH available in the tissue. This is an important indication for the possible pathological mechanism in action on ALS patients. © 2014

An age-related reduction of brain TBPH/TDP-43 levels precedes the onset of locomotion defects in a Drosophila ALS model

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An age-related reduction of brain TBPH/TDP-43 levels precedes the onset of locomotion defects in a Drosophila ALS model

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. The average age of onset of both sporadic and familial cases is 50-60. years of age. The presence of cytoplasmic inclusions of the RNA-binding protein TAR DNA-binding protein-43 (TDP-43) in the affected neurons is seen in 95% of the ALS cases, which results in TDP-43 nuclear clearance and loss of function. The Drosophila melanogaster ortholog of TDP-43 (TBPH) shares many characteristics with the human protein. Using a TDP-43 aggregation inducer previously developed in human cells, we created a transgenic fly that shows an adult locomotive defect. Phenotype onset correlates with a physiologically age-related drop of TDP-43/TBPH mRNA and protein levels, seen both in mice and flies. Artificial reduction of mRNA levels, in vivo, anticipates the locomotion defect to the larval stage. Our study links, for the first time, aggregation and the age-related, evolutionary conserved reduction of TDP-43/TBPH levels with the onset of an ALS-like locomotion defect in a Drosophila model. A similar process might trigger the human disease

Development of COVID-19 monoclonal antibodies and recombinant proteins as reagents for biomedical research and diagnostic test

Since SARS-COV-2 virus spread worldwide and COVID-19 turned rapidly into a pandemic illness, the necessity for vaccines and diagnostic tests became crucial. The viral surface is decorated with Spike, the major antigenic determinant and main target for vaccine development. Within Spike, the receptor binding domain (RBD), constitutes the main target of highly neutralizing antibodies found in COVID-19 convalescent plasma. Besides vaccination, another important aspect of Spike (and RBD) is their use as immunogen for the development of poli- and monoclonal antibodies (mAbs) for therapeutic and diagnostic purposes. Here we report the development and preliminary biochemical characterization of a set of monoclonal antibodies against the Spike RBD domain along with the recombinant expression of two mayor COVID-19 protein reagents: the viral Spike RBD domain and the extracellular domain of the human receptor ACE2. RBD and the extracellular domain of ACE2 (aa 1-740) were obtained through transient gene transfection (TGE) in two different mammalian cell culture systems: HEK293T adherent monolayers and Expi293 suspension cultures. Due to its low cost and ease scale-up, all transfections were carried with polyethyleneimine (PEI). Expressed proteins were purified from culture supernatants by immobilized metal affinity chromatography. Anti-RBD mAbs were developed from two different immunization schemes: one aimed to elicit antibodies with viral neutralizing potential, and the other with the ability to recognize denatured RBD for routinary lab immunoassays. To achieve this, the first group of mice was immunized with RBD in aluminium salts (RBD/Al) and the other with RBD emulsified in Freunds adyuvant (RBD/FA). Polyclonal and monoclonal antibody reactivities against native or denatured RBD forms were then assessed by ELISA. Complete RBD denaturation was followed by intrinsic fluorescence spectral changes upon different physicochemical stress treatments. As expected, RBD/Al immunized mice developed an antibody response shifted to native RBD while those immunized with RBD/FA showed a high response against both forms of the protein. In accordance with the observed polyclonal response, RBD/FA derived mAbs recognize both, native and denatured RBD. On the contrary, hybridomas generated from the RBD/Al protocol mostly recognize RBD in its native state. Further ELISA binding assays revealed that all RBD/FA derived mAbs can form a trimeric complex with ACE2 and RBD, denoting they would not have viral neutralizing activity. ELISA competition assays with the RBD/ACE2 complex aimed to determine the neutralization potential of the RBD/Al derived mAbs are under way. Overall, the anti-Spike RBD mAbs and the recombinant RBD and ACE2 proteins presented here constitute valuable tools for diverse COVID-19 academic research projects and local immunity surveillance testing.Fil: Acuña Intrieri, M. E. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Deriane, M.A. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Miller, C.. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Czibener, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Correa, E.. No especifíca;Fil: Cragnaz, L.. No especifíca;Fil: Guerra, L.. No especifíca;Fil: Rodriguez, S.. No especifíca;Fil: Goldbaum, F.A.. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; ArgentinaFil: Seigelchifer, M.. No especifíca;Fil: Comerci, Diego José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Montagna, Georgina Nuri. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Cerutti, Maria Laura. Universidad Nacional de San Martin. Centro de Rediseño E Ingenieria de Proteinas.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaLVII Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research y XVI Annual Meeting of the Argentinean Society for General MicrobiologyVirtualArgentinaSociedad Argentina de Investigación Bioquímica y Biología MolecularAsociación Civil de Microbiología Genera

Thioridazine reverts the phenotype in cellular and Drosophila models of amyotrophic lateral sclerosis by enhancing TDP-43 aggregate clearance

Brain inclusions mainly composed of misfolded and aggregated TAR DNA binding protein 43 (TDP-43), are characteristic hallmarks of amyotrophic lateral sclerosis (ALS). Irrespective of the role played by the inclusions, their reduction represents an important therapeutic pathway that is worth exploring. Their removal can either lead to the recovery of TDP-43 function by removing the self-templating conformers that sequester the protein in the inclusions, and/or eliminate any potential intrinsic toxicity of the aggregates. The search for curative therapies has been hampered by the lack of ALS models for use in high-throughput screening. We adapted, optimised, and extensively characterised our previous ALS cellular model for such use. The model demonstrated efficient aggregation of endogenous TDP-43, and concomitant loss of its splicing regulation function. We provided a proof-of-principle for its eventual use in high-throughput screening using compounds of the tricyclic family and showed that recovery of TDP-43 function can be achieved by the enhanced removal of TDP-43 aggregates by these compounds. We observed that the degradation of the aggregates occurs independent of the autophagy pathway beyond autophagosome-lysosome fusion, but requires a functional proteasome pathway. The in vivo translational effect of the cellular model was tested with two of these compounds in a Drosophila model expressing a construct analogous to the cellular model, where thioridazine significantly improved the locomotive defect. Our findings have important implications as thioridazine cleared TDP-43 aggregates and recovered TDP-43 functionality. This study also highlights the importance of a two-stage, in vitro and in vivo model system to cross-check the search for small molecules that can clear TDP-43 aggregates in TDP-43 proteinopathies

Desarrollo de un suero equino hiperinmune para el tratamiento de COVID-19 en Argentina

Fil: Pontoriero, A. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratorias. Centro Nacional de Influenza PAHO/WHO; Argentina.Fil: Baumeister, Elsa. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratorias. Centro Nacional de Influenza PAHO/WHO; Argentina.Fil: Campos, Ana. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratorias. Centro Nacional de Influenza PAHO/WHO; Argentina.Fil: Avaro, Martín. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratorias. Centro Nacional de Influenza PAHO/WHO; Argentina.Fil: Benedetti, Estefanía. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratorias. Centro Nacional de Influenza PAHO/WHO; Argentina.Fil: Dattero, María. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratorias. Centro Nacional de Influenza PAHO/WHO; ArgentinaFil: Zylberman, Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires, Argentina.Fil: Sanguineti, Santiago. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: Higa, Sandra V. Instituto Biológico Argentino S.A.I.C.; Buenos Aires, Argentina.Fil: Cerutti, María L. Universidad Nacional de San Martín. Centro de Rediseño e Ingenieria de Proteínas (CRIP); Buenos Aires, Argentina.Fil: Morrone Seijo, Susana M. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires, Argentina.Fil: Pardo, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires, Argentina.Fil: Muñoz, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires, Argentina.Fil: Acuña Intrieri, María E. Universidad Nacional de San Martín. Centro de Rediseño e Ingenieria de Proteínas (CRIP); Buenos Aires, Argentina.Fil: Alzogaray, Vanina A. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Berguer, Paula M. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Bocanera, Laura. mAbxience; Buenos Aires, Argentina.Fil: Bukata, Lucas. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: Bustelo, Marina S. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: Colonna, Mariana. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: Correa, Elisa. mAbxience; Buenos Aires, Argentina.Fil: Cragnaz, Lucía. mAbxience; Buenos Aires, Argentina.Fil: Dellafiore, María. mAbxience; Buenos Aires, Argentina.Fil: Foscaldi, Sabrina. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: González, Joaquín V. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: Guerra, Luciano L. mAbxience; Buenos Aires, Argentina.Fil: Klinke, Sebastián. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Labanda, María S. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Lauché, Constanza. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: López, Juan C. Instituto Biológico Argentino S.A.I.C.; Buenos Aires, Argentina.Fil: Martínez, Anabela M. Instituto Biológico Argentino S.A.I.C.; Buenos Aires, Argentina.Fil: Otero, Lisandro H. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Peyric, Elías H. Instituto Biológico Argentino S.A.I.C.; Buenos Aires, Argentina.Fil: Ponziani, Pablo F. Instituto Biológico Argentino S.A.I.C.; Buenos Aires, Argentina.Fil: Ramondino, Romina. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: Rinaldi, Jimena. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Rodríguez, Santiago. mAbxience; Buenos Aires, Argentina.Fil: Russo, Javier E. Instituto Biológico Argentino S.A.I.C.; Buenos Aires, Argentina.Fil: Russo, Mara L. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología. Servicio de Virosis Respiratorias. Centro Nacional de Influenza PAHO/WHO; Argentina.Fil: Saavedra, Soledad L. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Seigelchifer, Mauricio. mAbxience; Buenos Aires, Argentina.Fil: Sosa, Santiago. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.Fil: Vilariño, Claudio. Universidad Nacional de San Martín. Centro de Rediseño e Ingenieria de Proteínas (CRIP); Buenos Aires, Argentina.Fil: López Biscayart, Patricia. Instituto Biológico Argentino S.A.I.C.; Buenos Aires, Argentina.Fil: Corley, Esteban. mAbxience; Buenos Aires, Argentina.Fil: Spatz, Linus. INMUNOVA S.A.; Buenos Aires, Argentina.Fil: Goldbaum, Fernando A. Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBA). Fundación Instituto Leloir. Laboratorio de Inmunología y Microbiología Molecular; Buenos Aires, Argentina.The disease named COVID-19, caused by the SARS-CoV-2 coronavirus, is currently generating a global pandemic. Vaccine development is no doubt the best long-term immunological approach, but in the current epidemiologic and health emergency there is a need for rapid and effective solutions. Convalescent plasma is the only antibody-based therapy available for COVID-19 patients to date. Equine polyclonal antibodies (EpAbs) put forward a sound alternative. The new generation of processed and purified EpAbs containing highly purified F(ab')2 fragments demonstrated to be safe and well tolerated. EpAbs are easy to manufacture allowing a fast development and scaling up for a treatment. Based on these ideas, we present a new therapeutic product obtained after immunization of horses with the receptor-binding domain of the viral Spike glycoprotein. Our product shows around 50 times more potency in in vitro seroneutralization assays than the average of convalescent plasma. This result may allow us to test the safety and efficacy of this product in a phase 2/3 clinical trial to be conducted in July 2020 in the metropolitan area of Buenos Aires, Argentina