Maria Garcia-bravo - Academia.edu (original) (raw)

Papers by Maria Garcia-bravo

Huntington's disease (HD) is an incurable inherited brain disorder characterized by massive d... more Huntington's disease (HD) is an incurable inherited brain disorder characterized by massive degeneration of striatal neurons, which correlates with abnormal accumulation of misfolded mutant huntingtin (mHTT) protein. Research on HD has been hampered by the inability to study early dysfunction and progressive degeneration of human striatal neurons in vivo. To investigate human pathogenesis in a physiologically relevant context, we transplanted human pluripotent stem cell-derived neural progenitor cells (hNPCs) from control and HD patients into the striatum of newborn mice. Chimeric mice were subjected to behavioral testing and implanted human cells were examined by immunohistochemistry and electron microscopy. Most hNPCs differentiated into striatal neurons that projected to their target areas and established synaptic connections within the host basal ganglia circuitry. Remarkably, HD human striatal neurons first developed mHTT oligomers, which primarily targeted endoplasmic reti...

Each row indicates the relative fluorescence (RF) values for DAPI and HNF-1A (RF) of all... more Each row indicates the relative fluorescence (RF) values for DAPI and HNF-1A (RF) of all nuclei detected in each BMDH were named alphabetically and classified according to its morphology (as Type I, II or III).</p

Cellular and Molecular Life Sciences, Aug 1, 2023

Huntington's disease (HD) is an incurable inherited brain disorder characterised by massive degen... more Huntington's disease (HD) is an incurable inherited brain disorder characterised by massive degeneration of striatal neurons, which correlates with abnormal accumulation of misfolded mutant huntingtin (mHTT) protein. Research on HD has been hampered by the inability to study early dysfunction and progressive degeneration of human striatal neurons in vivo. To investigate human pathogenesis in a physiologically relevant context, we transplanted human pluripotent stem cell-derived neural progenitor cells (hNPCs) from control and HD patients into the striatum of newborn mice. Most hNPCs differentiated into striatal neurons that projected to their target areas and established synaptic connexions within the host basal ganglia circuitry. Remarkably, HD human striatal neurons first developed soluble forms of mHTT, which primarily targeted endoplasmic reticulum, mitochondria and nuclear membrane to cause structural alterations. Furthermore, HD human cells secreted extracellular vesicles containing mHTT monomers and oligomers, which were internalised by non-mutated mouse striatal neurons triggering cell death. We conclude that interaction of mHTT soluble forms with key cellular organelles initially drives disease progression in HD patients and their transmission through exosomes contributes to spread the disease in a non-cell autonomous manner. Cinta Gomis and Cristina Vila contributed equally to the work.

Sensors and Actuators A-physical, Mar 1, 2023

Clinical Genetics

CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a pub... more CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on Rare Diseases currently consists of 75 research groups belonging to universities, research centers and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical and cellular research of rare diseases. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this paper, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions towards the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to rare disease research. This article is protected by copyright. All rights reserved.

The Journal of Pathology

Despite the well‐known hepatoprotective role of the epidermal growth factor receptor (EGFR) pathw... more Despite the well‐known hepatoprotective role of the epidermal growth factor receptor (EGFR) pathway upon acute damage, its specific actions during chronic liver disease, particularly cholestatic injury, remain ambiguous and unresolved. Here, we analyzed the consequences of inactivating EGFR signaling in the liver on the regenerative response following cholestatic injury. For that, transgenic mice overexpressing a dominant negative mutant human EGFR lacking tyrosine kinase activity (ΔEGFR) in albumin‐positive cells were submitted to liver damage induced by 3,5‐diethoxycarbonyl‐1,4‐dihydrocollidine (DDC), an experimental model resembling human primary sclerosing cholangitis. Our results show an early activation of EGFR after 1–2 days of a DDC‐supplemented diet, followed by a signaling switch‐off. Furthermore, ΔEGFR mice showed less liver damage and a more efficient regeneration following DDC injury. Analysis of the mechanisms driving this effect revealed an enhanced activation of mito...

The CRISPR Journal

Knockout mice for human disease-causing genes provide valuable models in which new therapeutic ap... more Knockout mice for human disease-causing genes provide valuable models in which new therapeutic approaches can be tested. Electroporation of genome editing tools into zygotes, in vitro or within oviducts, allows for the generation of targeted mutations in a shorter time. We have generated mouse models deficient in genes involved in metabolic rare diseases (Primary Hyperoxaluria Type 1 Pyruvate Kinase Deficiency) or in a tumor suppressor gene (Rasa1). Pairs of guide RNAs were designed to generate controlled deletions that led to the absence of protein. In vitro or in vivo ribonucleoprotein (RNP) electroporation rendered more than 90% and 30% edited newborn animals, respectively. Mice lines with edited alleles were established and disease hallmarks have been verified in the three models that showed a high consistency of results and validating RNP electroporation into zygotes as an efficient technique for disease modeling without the need to outsource to external facilities.

A. Presence of nuclei of different morphology in several BMDH as iden... more A. Presence of nuclei of different morphology in several BMDH as identified by immunofluorescence. Three examples (i, ii and iii) are shown. Arrowhead, BMDH nucleus with hepatocyte-like nuclear morphology; Arrow, BMDH nucleus with a different morphology to a hepatocyte nucleus. 20 µm scale bars are shown. B. Classification of the different BMDH nuclei according to their morphology and DAPI DNA-staining. Three different types of nuclei were defined; hepatocyte-like (Type I), hematopoietic-like (Type III) and non hepatocyte-non hematopoietic-like (Type II). 20 µm scale bars are shown. C. Histogram representing the quantification of DAPI relative fluorescence in the different BMDH (black bars), hepatocyte and hematopoietic cell nuclei (white bars). The data shown correspond to 57 nuclei of 35 BMDH examined in hepatic sections from several animals in two independent experiments ± SD. *p<0.05; D. Identifying the origin of BMDH nuclei by Y-FISH and immunofluorescence. Nuclei positive for the Y-chromosome arise from the exogenous BM. Yellow circle indicates one BM-derived nucleus. 20 µm scale bars are shown.</p

ChEA software was used to identify transcription factors that could regulate the express... more ChEA software was used to identify transcription factors that could regulate the expression of BMDH genes with respect to microdissected cells (hematopoietic and hepatocytes) and mouse macrophages, B cells and liver tissue.1TF: transcription factor symbol; Expt ID: PubMed ID for the publication.2Number of the BMDH genes regulated by the TF.3Significance of the gene overlapping.</p

Molecular Therapy - Methods & Clinical Development, 2021

Pyruvate kinase deficiency (PKD) is a rare autosomal recessive disorder caused by mutations in th... more Pyruvate kinase deficiency (PKD) is a rare autosomal recessive disorder caused by mutations in the PKLR gene. PKD is characterized by non-spherocytic hemolytic anemia of variable severity and may be fatal in some cases during early childhood. Although not considered the standard of care, allogeneic stem cell transplantation has been shown as a potentially curative treatment, limited by donor availability, toxicity, and incomplete engraftment. Preclinical studies were conducted to define conditions to enable consistent therapeutic reversal, which were based on our previous data on lentiviral gene therapy for PKD. Improvement of erythroid parameters was identified by the presence of 20%–30% healthy donor cells. A minimum vector copy number (VCN) of 0.2−0.3 was required to correct PKD when corrected cells were transplanted in a mouse model for PKD. Biodistribution and pharmacokinetics studies, with the aim of conducting a global gene therapy clinical trial for PKD patients (RP-L301-0119), demonstrated that genetically corrected cells do not confer additional side effects. Moreover, a clinically compatible transduction protocol with mobilized peripheral blood CD34+ cells was optimized, thus facilitating the efficient transduction on human cells capable of repopulating the hematopoiesis of immunodeficient mice. We established conditions for a curative lentiviral vector gene therapy protocol for PKD.

Research on neurodegenerative disorders has been hampered by the limited access to patients’ brai... more Research on neurodegenerative disorders has been hampered by the limited access to patients’ brain tissue and the absence of relevant physiological models with human neurons, accounting for the little success of clinical trials. Moreover, post-mortem samples cannot provide a detailed picture of the complex pathological mechanisms taking place throughout the course of the disease. This holds particularly true for Huntington’s disease (HD), an incurable inherited brain disorder marked by a massive striatal degeneration due to abnormal accumulation of misfolded huntingtin protein. To characterize progressive human neurodegenerationin vivo, we transplanted induced pluripotent stem cell-derived human neural progenitor cells (hNPCs) from control (CTR-hNPCs) and HD patients (HD-hNPCs) into the striatum of neonatal wild-type mice. Implanted human cells were examined by immunohistochemistry and electron microscopy, and chimeric mice were subjected to behavioral testing. Most grafted hNPCs di...

Molecular Neurobiology, 2020

Human pluripotent stem cells (hPSCs) are a powerful tool for modelling human development. In rece... more Human pluripotent stem cells (hPSCs) are a powerful tool for modelling human development. In recent years, hPSCs have become central in cell-based therapies for neurodegenerative diseases given their potential to replace affected neurons. However, directing hPSCs into specific neuronal types is complex and requires an accurate protocol that mimics endogenous neuronal development. Here we describe step-by-step a fast feeder-free neuronal differentiation protocol to direct hPSCs to mature forebrain neurons in 37 days in vitro (DIV). The protocol is based upon a combination of specific morphogens, trophic and growth factors, ions, neurotransmitters and extracellular matrix elements. A human-induced PSC line (Ctr-Q33) and a human embryonic stem cell line (GEN-Q18) were used to reinforce the potential of the protocol. Neuronal activity was analysed by single-cell calcium imaging. At 8 DIV, we obtained a homogeneous population of hPSC-derived neuroectodermal progenitors which self-arrange...

Stem Cells, 2019

Adult hepatic progenitor cells (HPCs)/oval cells are bipotential progenitors that participate in ... more Adult hepatic progenitor cells (HPCs)/oval cells are bipotential progenitors that participate in liver repair responses upon chronic injury. Recent findings highlight HPCs plasticity and importance of the HPCs niche signals to determine their fate during the regenerative process, favoring either fibrogenesis or damage resolution. Transforming growth factor-β (TGF-β) and hepatocyte growth factor (HGF) are among the key signals involved in liver regeneration and as component of HPCs niche regulates HPCs biology. Here, we characterize the TGF-β-triggered epithelial–mesenchymal transition (EMT) response in oval cells, its effects on cell fate in vivo, and the regulatory effect of the HGF/c-Met signaling. Our data show that chronic treatment with TGF-β triggers a partial EMT in oval cells based on coexpression of epithelial and mesenchymal markers. The phenotypic and functional profiling indicates that TGF-β-induced EMT is not associated with stemness but rather represents a step forward...

Gene Therapy - Tools and Potential Applications, 2013

Disease Models & Mechanisms, 2016

Type 2 diabetes mellitus is a complex metabolic disease and its pathogenesis involves abnormaliti... more Type 2 diabetes mellitus is a complex metabolic disease and its pathogenesis involves abnormalities in both peripheral insulin action and insulin secretion. Previous in vitro data showed that insulin receptor isoform A, but not B, favours basal glucose uptake through its specific association with endogenous GLUT1/2 in murine hepatocytes and beta cells. With this background, we hypothesized that hepatic expression of insulin receptor isoform A in a mouse model of type 2 diabetes could potentially increase the glucose uptake of these cells, decreasing the hyperglycaemia and therefore ameliorating the diabetic phenotype. To assure this hypothesis, we have developed recombinant adeno-associated viral vectors expressing insulin receptor isoform A (IRA) or isoform B (IRB) under the control of a hepatocyte-specific promoter. Our results demonstrate that in the long term, hepatic expression of IRA in diabetic mice is more efficient than IRB in ameliorating glucose intolerance. Consequently, it impairs the induction of compensatory mechanisms through beta cell hyperplasia and/or hypertrophy that finally lead to beta cell failure, reverting the diabetic phenotype in about 8 weeks. Our data suggest that long-term hepatic expression of IRA could be a promising therapeutic approach for the treatment of type 2 diabetes mellitus.

Stem Cell Research & Therapy, 2016

Background: Several studies have reported the direct conversion of mouse fibroblasts to hepatocyt... more Background: Several studies have reported the direct conversion of mouse fibroblasts to hepatocyte-like cells with different degrees of maturation by expression of hepatic fate-conversion factors. Methods: We have used a combination of lentiviral vectors expressing hepatic fate-conversion factors with Oct4, Sox2, Klf4, and Myc to convert mouse embryonic fibroblasts into hepatic cells. Results: We have generated hepatic cells with progenitor-like features (iHepL cells). iHepL cells displayed basic hepatocyte functions but failed to perform functions characteristic of mature hepatocytes such as significant Cyp450 or urea cycle activities. iHepL cells expressed multiple hepatic-specific transcription factors and functional genes characteristic of immature hepatocytes and cholangiocytes, as well as high levels of Foxl1, Cd24a, and Lgr5, specific markers of hepatic progenitor cells. When transplanted into partial hepatectomized and hepatic irradiated mice, they differentiated into hepatocytes and cholangiocytes. However, iHepL cells formed malignant non-teratoma cell aggregations in one out of five engrafted livers and five out of five xenografts assays. All the cells in these tumors had silenced key hepatic fate-conversion factors, and lost hepatic features. Conclusions: This study highlights the dangers of using pluripotency factors in reprogramming strategies when fate-conversion factors are silenced in vivo, and urges us to perform extensive tumorigenic tests in reprogrammed cells.

Modern Tools for Genetic Engineering, 2016

Over the last years, an important development has allowed the scientific community to address a p... more Over the last years, an important development has allowed the scientific community to address a precise and accurate modification of the genome. The first probe of concept appeared with the design and use of engineered zinc-finger nucleases (ZFNs), which was expanded later on with the discovery and engineering of meganucleases and transcription activator-like effector nucleases (TALENs) and finally democratized and made easily available to the whole scientific community with the discovery of the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 nuclease combination technology. The availability of these tools has allowed a precise gene editing, such as knockout of a specific gene or the correction of a defective gene by means of homologous recombination (HR), taking advantage of the endogenous cell repair machinery. This process was already known and used but was inefficient-efficiency that has been increased more than 100-fold with the addition of the mentioned specific nucleases to the process. Apart from the proper design of the nucleases to recognize and cut the selected site in the cell genome, two main goals need to be adequately addressed to optimize its function: the delivery of the tools into the desired cells and the selection of those where the gene editing process has occurred correctly. Both steps can be easily solved when the source of cells is extensive or can be expanded and manipulated in vitro extensively, such as immortalized cell lines or pluripotent stem cells (embryonic stem cells and induced pluripotent stem cells). However, both steps are critical in the case of primary cells, such as the hematopoietic stem cells (HSCs). HSCs are a rare cell population present in the bone marrow (BM) of higher mammals, and it is the responsible for the maintenance and