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Casalia ML, Casabona JC, García C, Cavaliere Candedo V, Quintá HR, Farías MI, Gonzalez J, Gonzalez Morón D, Córdoba M, Consalvo D, Mostoslavsky G, Urbano FJ, Pasquini J, Murer MG, Rela L, Kauffman MA, Pitossi FJ. A familiar study on self-limited childhood epilepsy patients using hIPSC-derived neurons shows a bias towards immaturity at the morphological, electrophysiological and gene expression levels. Stem Cell Res Ther 2021; 12:590. [PMID: 34823607 PMCID: PMC8620942 DOI: 10.1186/s13287-021-02658-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 10/31/2021] [Indexed: 12/28/2022] Open
Abstract
Background Self-limited Childhood Epilepsies are the most prevalent epileptic syndrome in children. Its pathogenesis is unknown. In this disease, symptoms resolve spontaneously in approximately 50% of patients when maturity is reached, prompting to a maturation problem. The purpose of this study was to understand the molecular bases of this disease by generating and analyzing induced pluripotent stem cell-derived neurons from a family with 7 siblings, among whom 4 suffer from this disease.
Methods Two affected siblings and, as controls, a healthy sister and the unaffected mother of the family were studied. Using exome sequencing, a homozygous variant in the FYVE, RhoGEF and PH Domain Containing 6 gene was identified in the patients as a putative genetic factor that could contribute to the development of this familial disorder. After informed consent was signed, skin biopsies from the 4 individuals were collected, fibroblasts were derived and reprogrammed and neurons were generated and characterized by markers and electrophysiology. Morphological, electrophysiological and gene expression analyses were performed on these neurons. Results Bona fide induced pluripotent stem cells and derived neurons could be generated in all cases. Overall, there were no major shifts in neuronal marker expression among patient and control-derived neurons. Compared to two familial controls, neurons from patients showed shorter axonal length, a dramatic reduction in synapsin-1 levels and cytoskeleton disorganization. In addition, neurons from patients developed a lower action potential threshold with time of in vitro differentiation and the amount of current needed to elicit an action potential (rheobase) was smaller in cells recorded from NE derived from patients at 12 weeks of differentiation when compared with shorter times in culture. These results indicate an increased excitability in patient cells that emerges with the time in culture. Finally, functional genomic analysis showed a biased towards immaturity in patient-derived neurons. Conclusions We are reporting the first in vitro model of self-limited childhood epilepsy, providing the cellular bases for future in-depth studies to understand its pathogenesis. Our results show patient-specific neuronal features reflecting immaturity, in resonance with the course of the disease and previous imaging studies. Supplementary Information The online version contains supplementary material available at 10.1186/s13287-021-02658-2.
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Affiliation(s)
| | | | - Corina García
- Institute Leloir Foundation- IIBBA-CONICET, Buenos Aires, Argentina
| | | | - Héctor Ramiro Quintá
- CONICET and Laboratorio de Medicina Experimental "Dr. J Toblli", Hospital Alemán, Buenos Aires, Argentina
| | | | - Joaquín Gonzalez
- Institute Leloir Foundation- IIBBA-CONICET, Buenos Aires, Argentina
| | - Dolores Gonzalez Morón
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina
| | - Marta Córdoba
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina
| | - Damian Consalvo
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina
| | - Gustavo Mostoslavsky
- Center For Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, USA
| | - Francisco J Urbano
- Department of Physiology, Molecular and Cellular Biology "Dr. Héctor Maldonado", Faculty of Exact and Natural Sciences, University of Buenos Aires, IFIBYNE-CONICET, Buenos Aires, Argentina
| | - Juana Pasquini
- Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina
| | - Mario Gustavo Murer
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Ciencias Fisiológicas, Grupo de Neurociencia de Sistemas, Buenos Aires, Argentina.,Universidad de Buenos Aires - CONICET, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO), Buenos Aires, Argentina
| | - Lorena Rela
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Ciencias Fisiológicas, Grupo de Neurociencia de Sistemas, Buenos Aires, Argentina.,Universidad de Buenos Aires - CONICET, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO), Buenos Aires, Argentina
| | - Marcelo A Kauffman
- Consultorio y Laboratorio de Neurogenética, Centro Universitario de Neurología "José María Ramos Mejía" Facultad de Medicina, UBA & Instituto de Investigaciones en Medicina Traslacional, Facultad de Ciencias Biomédicas, Universidad Austral-CONICET, Buenos Aires, Argentina.
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Ferreira de Lima Neto D, Bonafe CFS, Arns CW. Influence of high hydrostatic pressure on epitope mapping of tobacco mosaic virus coat protein. Viral Immunol 2014; 27:60-74. [PMID: 24605789 DOI: 10.1089/vim.2013.0088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In this study, we investigated the effect of high hydrostatic pressure (HHP) on tobacco mosaic virus (TMV), a model virus in immunology and one of the most studied viruses to date. Exposure to HHP significantly altered the recognition epitopes when compared to sera from mice immunized with native virus. These alterations were studied further by combining HHP with urea or low temperature and then inoculating the altered virions into Balb-C mice. The antibody titers and cross-reactivity of the resulting sera were determined by ELISA. The antigenicity of the viral particles was maintained, as assessed by using polyclonal antibodies against native virus. The antigenicity of canonical epitopes was maintained, although binding intensities varied among the treatments. The patterns of recognition determined by epitope mapping were cross checked with the prediction algorithms for the TMVcp amino acid sequence to infer which alterations had occurred. These findings suggest that different cleavage sites were exposed after the treatments and this was confirmed by epitope mapping using sera from mice immunized with virus previously exposed to HHP.
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Affiliation(s)
- Daniel Ferreira de Lima Neto
- 1 Laboratório de Virologia Animal, Departamentos de 1Genética, Evolução e Bioagentes, e Universidade Estadual de Campinas (UNICAMP) , Cidade Universitária Zeferino Vaz, Campinas, SP, Brazil
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Bixler GS, Atassi MZ. T cell recognition of myoglobin. Localization of the sites stimulating T cell proliferative responses by synthetic overlapping peptides encompassing the entire molecule. JOURNAL OF IMMUNOGENETICS 1984; 11:339-53. [PMID: 6085693 DOI: 10.1111/j.1744-313x.1984.tb00820.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A comprehensive strategy for the systematic localization of all continuous antigenic sites within a protein has previously been introduced by this laboratory. The strategy consists of studying the immunochemical activity of a series of consecutive synthetic peptides that encompass the entire protein chain and that are uniform in size and in overlap at their N- and C-terminals with neighbouring peptides. By application of this strategy to sperm whale myoglobin, we have been able to delineate the continuous sites of T cell recognition of myoglobin in three high responder mouse strains. Thirteen 17-residue peptides that encompass the entire myoglobin chain and overlap by five residues at both ends were synthesized, purified and characterized. The peptides were examined in vitro for their ability to stimulate lymph node cells from myoglobin-primed DBA/2 (H-2d), BALB/c (H-2d) and SJL (H-2s) mice as well as long-term cultures of myoglobin-specific T cells. Several regions of the molecule (T sites) were found to stimulate myoglobin-primed lymph node cells and myoglobin-specific longterm T cell cultures. This strategy has enabled the localization of the full profile of dominant sites of T cell recognition in myoglobin for these mouse strains. Of these T sites, one region, residues 107-125, was clearly immunodominant in these strains and was found to coincide with the antigenic (i.e. antibody binding) site 4 of myoglobin. Also, other regions stimulated T cells and appeared to coincide with previously known antigenic sites. It is noteworthy that, in addition to sites recognized by both T and B cells, the protein has other sites which are recognized exclusively by T cells and to which no detectable antibody response is directed.
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Bixler GS, Yoshida T, Atassi MZ. T cell recognition of lysozyme. IV. Localization and genetic control of the continuous T cell recognition sites by synthetic overlapping peptides representing the entire protein chain. JOURNAL OF IMMUNOGENETICS 1984; 11:327-37. [PMID: 6085692 DOI: 10.1111/j.1744-313x.1984.tb00819.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Recently, this laboratory has developed a comprehensive strategy for the systematic localization of all the 'continuous' antigenic (as well as other binding) sites of complex multivalent protein antigens involved in B and T cell recognition. The strategy depends on the synthesis of consecutive overlapping peptides that together account for the entire protein chain. This strategy was applied here for the localization of the 'continuous' T cell recognition sites of hen egg lysozyme. Eight overlapping peptides encompassing the entire protein chain of lysozyme were synthesized and examined for their ability to stimulate in vitro proliferation of T cells from several mouse strains (A/J, H-2a; BALB/c and DBA/2, H-2d; B10.BR, H-2k; DBA/1, H-2q; SJL, H-2s) that had been primed with native lysozyme. This approach enabled the identification of a full profile of in vitro active lysozyme peptides and the localization of four major T cell recognition sites, three of which were subject to individual control.
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Atassi MZ. Precise determination of protein antigenic structures has unravelled the molecular immune recognition of proteins and provided a prototype for synthetic mimicking of other protein binding sites. Mol Cell Biochem 1980; 32:21-43. [PMID: 6160381 DOI: 10.1007/bf00421293] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Intensive research in the author's laboratory had culminated in the determination and synthesis of all the antigenic sites of myoglobin in 1975 and of lysozyme in 1978. Very recently most of the antigenic sites of serum albumin were also localized and synthesized. These investigations provided the first unique insight into the molecular features responsible for the immune recognition of protein antigens and of the factors which determine and regulate the antigenicity of the sites. But moreover, these studies have charted a multi-approach chemical strategy for investigation and synthetic duplication of protein binding sites. Furthermore, the concept of 'surface-simulation' synthesis, which we introduced and developed during our determination of the antigenic structure of lysozyme, has provided a remarkable dimension of unlimited versatility for the synthetic mimicking of any type of protein binding sites. In this concept, the spatially adjacent residues of a protein binding site are linked directly via peptide bonds with appropriate spacers into a single peptide which does not exist in the protein but mimicks a surface region of it. This has proved to be a powerful concept in protein molecular recognition and has opened up many untapped avenues in investigation, duplication and perhaps manipulation of a variety of protein activities. In fact, binding sites representing other protein activities (including antibody combining sites) have or are now being mimicked synthetically in our laboratory by the concept of surface-simulation synthesis.
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