Publications by authors named "Eva García-Alegria"

15 Publications

  • Page 1 of 1

Transcriptional control of blood cell emergence.

FEBS Lett 2019 12 31;593(23):3304-3315. Epub 2019 Aug 31.

Developmental Haematopoiesis Group, Faculty of Biology, Medicine and Health, the University of Manchester, UK.

The haematopoietic system is established during embryonic life through a series of developmental steps that culminates with the generation of haematopoietic stem cells. Characterisation of the transcriptional network that regulates blood cell emergence has led to the identification of transcription factors essential for this process. Among the many factors wired within this complex regulatory network, ETV2, SCL and RUNX1 are the central components. All three factors are absolutely required for blood cell generation, each one controlling a precise step of specification from the mesoderm germ layer to fully functional blood progenitors. Insight into the transcriptional control of blood cell emergence has been used for devising protocols to generate blood cells de novo, either through reprogramming of somatic cells or through forward programming of pluripotent stem cells. Interestingly, the physiological process of blood cell generation and its laboratory-engineered counterpart have very little in common.
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http://dx.doi.org/10.1002/1873-3468.13585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6916194PMC
December 2019

Early Human Hemogenic Endothelium Generates Primitive and Definitive Hematopoiesis In Vitro.

Stem Cell Reports 2018 11 25;11(5):1061-1074. Epub 2018 Oct 25.

Developmental Haematopoiesis Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK. Electronic address:

The differentiation of human embryonic stem cells (hESCs) to hematopoietic lineages initiates with the specification of hemogenic endothelium, a transient specialized endothelial precursor of all blood cells. This in vitro system provides an invaluable model to dissect the emergence of hematopoiesis in humans. However, the study of hematopoiesis specification is hampered by a lack of consensus in the timing of hemogenic endothelium analysis and the full hematopoietic potential of this population. Here, our data reveal a sharp decline in the hemogenic potential of endothelium populations isolated over the course of hESC differentiation. Furthermore, by tracking the dynamic expression of CD31 and CD235a at the onset of hematopoiesis, we identified three populations of hematopoietic progenitors, representing primitive and definitive subsets that all emerge from the earliest specified hemogenic endothelium. Our data establish that hemogenic endothelium populations endowed with primitive and definitive hematopoietic potential are specified simultaneously from the mesoderm in differentiating hESCs.
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http://dx.doi.org/10.1016/j.stemcr.2018.09.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6234921PMC
November 2018

MXD1 localizes in the nucleolus, binds UBF and impairs rRNA synthesis.

Oncotarget 2016 10;7(43):69536-69548

Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria, and Department of Molecular Biology, University of Cantabria, Santander, Spain.

MXD1 is a protein that interacts with MAX, to form a repressive transcription factor. MXD1-MAX binds E-boxes. MXD1-MAX antagonizes the transcriptional activity of the MYC oncoprotein in most models. It has been reported that MYC overexpression leads to augmented RNA synthesis and ribosome biogenesis, which is a relevant activity in MYC-mediated tumorigenesis. Here we describe that MXD1, but not MYC or MNT, localizes to the nucleolus in a wide array of cell lines derived from different tissues (carcinoma, leukemia) as well as in embryonic stem cells. MXD1 also localizes in the nucleolus of primary tissue cells as neurons and Sertoli cells. The nucleolar localization of MXD1 was confirmed by co-localization with UBF. Co-immunoprecipitation experiments showed that MXD1 interacted with UBF and proximity ligase assays revealed that this interaction takes place in the nucleolus. Furthermore, chromatin immunoprecipitation assays showed that MXD1 was bound in the transcribed rDNA chromatin, where it co-localizes with UBF, but also in the ribosomal intergenic regions. The MXD1 involvement in rRNA synthesis was also suggested by the nucleolar segregation upon rRNA synthesis inhibition by actinomycin D. Silencing of MXD1 with siRNAs resulted in increased synthesis of pre-rRNA while enforced MXD1 expression reduces it. The results suggest a new role for MXD1, which is the control of ribosome biogenesis. This new MXD1 function would be important to curb MYC activity in tumor cells.
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http://dx.doi.org/10.18632/oncotarget.11766DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5342496PMC
October 2016

Emerging concepts for the in vitro derivation of murine haematopoietic stem and progenitor cells.

FEBS Lett 2016 Nov 28;590(22):4116-4125. Epub 2016 Jul 28.

Cancer Research UK Stem Cell Haematopoiesis Group, Cancer Research UK Manchester Institute, The University of Manchester, UK.

Well into the second decade of the 21st century, the field of regenerative medicine is bursting with hopes and promises to heal young and old. The bespoken generation of cells is thought to offer unprecedented cures for a vast range of diseases. Haematological disorders have already benefited tremendously from stem cell therapy in the form of bone marrow transplantation. However, lack of compatible donors often means that patients remain on transplantation waiting lists for too long. The in vitro derivation of haematopoietic stem cells offers the possibility to generate tailor-made cells for the treatment of these patients. Promising approaches to generate in vitro-derived blood progenitors include the directed differentiation of pluripotent stem cells and the reprogramming of somatic cells.
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http://dx.doi.org/10.1002/1873-3468.12300DOI Listing
November 2016

New insights into the regulation by RUNX1 and GFI1(s) proteins of the endothelial to hematopoietic transition generating primordial hematopoietic cells.

Cell Cycle 2016 Aug 11;15(16):2108-2114. Epub 2016 Jul 11.

a CRUK Stem Cell Biology, Cancer Research UK Manchester Institute , Manchester , UK.

The first hematopoietic cells are generated very early in ontogeny to support the growth of the embryo and to provide the foundation to the adult hematopoietic system. There is a considerable therapeutic interest in understanding how these first blood cells are generated in order to try to reproduce this process in vitro. This would allow generating blood products, or hematopoietic cell populations from embryonic stem (ES) cells, induced pluripotent stem cells or through directed reprogramming. Recent studies have clearly established that the first hematopoietic cells originate from a hemogenic endothelium (HE) through an endothelial to hematopoietic transition (EHT). The molecular mechanisms underlining this transition remain largely unknown with the exception that the transcription factor RUNX1 is critical for this process. In this Extra Views report, we discuss our recent studies demonstrating that the transcriptional repressors GFI1 and GFI1B have a critical role in the EHT. We established that these RUNX1 transcriptional targets are actively implicated in the downregulation of the endothelial program and the loss of endothelial identity during the formation of the first blood cells. In addition, our results suggest that GFI1 expression provides an ideal novel marker to identify, isolate and study the HE cell population.
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http://dx.doi.org/10.1080/15384101.2016.1203491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4993433PMC
August 2016

Concise Review: Recent Advances in the In Vitro Derivation of Blood Cell Populations.

Stem Cells Transl Med 2016 10 7;5(10):1330-1337. Epub 2016 Jul 7.

Cancer Research UK Stem Cell Haematopoiesis Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, United Kingdom

: Hematopoietic cell-based therapies are currently available treatment options for many hematological and nonhematological disorders. However, the scarcity of allogeneic donor-derived cells is a major hurdle in treating these disorders. Embryonic stem cell-based directed differentiation and direct reprogramming of somatic cells provide excellent tools for the potential generation of hematopoietic stem cells usable in the clinic for cellular therapies. In addition to blood stem cell transplantation, mature blood cells such as red blood cells, platelets, and engineered T cells have also been increasingly used to treat several diseases. Besides cellular therapies, induced blood progenitor cells generated from autologous sources (either induced pluripotent stem cells or somatic cells) can be useful for disease modeling of bone marrow failures and acquired blood disorders. However, although great progress has been made toward these goals, we are still far from the use of in vitro-derived blood products in the clinic. We review the current state of knowledge on the directed differentiation of embryonic stem cells and the reprogramming of somatic cells toward the generation of blood stem cells and derivatives.

Significance: Hematopoietic cell-based therapies are currently available treatment options for many hematological and nonhematological disorders. However, the scarcity of allogeneic donor-derived cells is a major hurdle in treating these disorders. The current state of knowledge on the directed differentiation of embryonic stem cells and the reprogramming of somatic cells toward the generation of blood stem cells and derivatives is reviewed.
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http://dx.doi.org/10.5966/sctm.2016-0039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5031184PMC
October 2016

Graphene Oxide promotes embryonic stem cell differentiation to haematopoietic lineage.

Sci Rep 2016 05 20;6:25917. Epub 2016 May 20.

Cancer Research UK Stem Cell Biology Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, United Kingdom.

Pluripotent stem cells represent a promising source of differentiated tissue-specific stem and multipotent progenitor cells for regenerative medicine and drug testing. The realisation of this potential relies on the establishment of robust and reproducible protocols of differentiation. Several reports have highlighted the importance of biomaterials in assisting directed differentiation. Graphene oxide (GO) is a novel material that has attracted increasing interest in the field of biomedicine. In this study, we demonstrate that GO coated substrates significantly enhance the differentiation of mouse embryonic stem (ES) cells to both primitive and definitive haematopoietic cells. GO does not affect cell proliferation or survival of differentiated cells but rather enhances the transition of haemangioblasts to haemogenic endothelial cells, a key step during haematopoietic specification. Importantly, GO also improves, in addition to murine, human ES cell differentiation to blood cells. Taken together, our study reveals a positive role for GO in haematopoietic differentiation and suggests that further functionalization of GO could represent a valid strategy for the generation of large numbers of functional blood cells. Producing these cells would accelerate haematopoietic drug toxicity testing and treatment of patients with blood disorders or malignancies.
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http://dx.doi.org/10.1038/srep25917DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873758PMC
May 2016

NUMB inactivation confers resistance to imatinib in chronic myeloid leukemia cells.

Cancer Lett 2016 May 2;375(1):92-99. Epub 2016 Mar 2.

Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria and Dpto. de Biología Molecular, Universidad de Cantabria, Santander, Spain. Electronic address:

Chronic myeloid leukemia (CML) progresses from a chronic to a blastic phase, where the leukemic cells are proliferative and undifferentiated. The CML is nowadays successfully treated with BCR-ABL kinase inhibitors as imatinib and its derivatives. NUMB is an evolutionary well-conserved protein initially described as a functional antagonist of NOTCH function. NUMB is an endocytic protein associated with receptor internalization, involved in multiple cellular functions. It has been reported that MSI2 protein, a NUMB inhibitor, is upregulated in CML blast crisis, whereas NUMB itself is downregulated. This suggest that NUMB plays a role in the malignant progression of CML. Here we have generated K562 cells (derived from CML in blast crisis) constitutively expressing a dominant negative form of NUMB (dnNUMB). We show that dnNUMB expression confers a high proliferative phenotype to the cells. Importantly, dnNUMB triggers a partial resistance to imatinib in these cells, antagonizing the apoptosis mediated by the drug. Interestingly, imatinib resistance is not linked to p53 status or NOTCH signaling, as K562 lack p53 and imatinib resistance is reproduced in the presence of NOTCH inhibitors. Taken together, our data support the hypothesis that NUMB activation could be a new therapeutic target in CML.
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http://dx.doi.org/10.1016/j.canlet.2016.02.037DOI Listing
May 2016

Mutation study of Spanish patients with hereditary hemorrhagic telangiectasia.

BMC Med Genet 2008 Aug 1;9:75. Epub 2008 Aug 1.

Centro de Investigaciones Biologicas, CSIC, Ramiro de Maeztu, 9, Madrid 28040, Spain.

Background: Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant and age-dependent vascular disorder characterised mainly by mutations in the Endoglin (ENG) or activin receptor-like kinase-1 (ALK1, ACVRL1) genes.

Methods: Here, we have identified 22 ALK1 mutations and 15 ENG mutations, many of which had not previously been reported, in independent Spanish families afflicted with HHT.

Results: We identified mutations in thirty-seven unrelated families. A detailed analysis of clinical symptoms was recorded for each patient analyzed, with a higher significant presence of pulmonary arteriovenous malformations (PAVM) in HHT1 patients over HHT2. Twenty-two mutations in ALK1 and fifteen in ENG genes were identified. Many of them, almost half, represented new mutations in ALK1 and in ENG. Missense mutations in ENG and ALK1 were localized in a tridimensional protein structure model.

Conclusion: Overall, ALK1 mutations (HHT2) were predominant over ENG mutations (HHT1) in our Spanish population, in agreement with previous data from our country and other Mediterranean countries (France, Italy), but different to Northern Europe or North America. There was a significant increase of PAVM associated with HHT1 over HHT2 in these families.
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http://dx.doi.org/10.1186/1471-2350-9-75DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2518546PMC
August 2008

Risk of cognitive impairment in female premutation carriers of fragile X premutation: analysis by means of robust segmented linear regression models.

Am J Med Genet B Neuropsychiatr Genet 2009 Mar;150B(2):262-70

Hospital de Cruces, Barakaldo, Bizkaia, Spain.

This report describes a study focused on the relationship between CGG repeat length, FMRP, mRNA levels and cognitive functioning in premutation carriers (PM) carriers of Fragile X Syndrome (FXS). We studied 60 females-43 with PM and 17 with normal (N) alleles-from 25 FXS Spanish families. The Wechsler scales were administered to all subjects and new blood samples and hair roots were taken to study mRNA and FMRP levels. Using lowess curves together with segmented models we showed that within the premutation range, IQ scores tend to decrease when the number of CGG repeats increases and the FMRP values decrease. Furthermore, we discovered cut-off points in the molecular variables that seem to change the probability of having some cognitive impairment. Specifically, for those PM females in the upper premutation range (CGG > or = 100) and with FMRP expression < 60% in hair roots, a 10% decrement of FMRP expression represents a significant decrease in IQ scores of about six points, which is more evident for Full-Scale IQ (P-value = 0.035) and Performance IQ (P-value = 0.045) than for Verbal IQ (P-value = 0.074). On the contrary, we did not find any significant correlation between FMR1 mRNA levels and the IQ scores, probably due to the fact that mRNA levels were measured in blood. In conclusion, our findings suggest that the PM can have some effect on cognitive ability in female carriers, although these effects may be subtle. In these cases, it would be advisable to carry out a hair root analysis of FMRP.
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http://dx.doi.org/10.1002/ajmg.b.30803DOI Listing
March 2009

Analysis of the molecular parameters that could predict the risk of manifesting premature ovarian failure in female premutation carriers of fragile X syndrome.

Menopause 2008 Sep-Oct;15(5):945-9

Molecular Genetics Laboratory, Cruces Hospital, Barakaldo, Bizkaia.

Objective: To study three molecular parameters (number of CGG repeats, X-inactivation ratio, and expression of FMR1 mRNA) in premutation carriers of fragile X syndrome with and without premature ovarian failure (POF) to find differences between these two groups that could be useful in reproductive counseling.

Design: A retrospective clinical and molecular genetic study of 42 known premutation carriers of fragile X syndrome aged 40 years or older, 25 with POF and 17 without. A blood sample to obtain mRNA was taken from all of them. They all lived in five autonomous communities in northern Spain.

Results: Although the relationship among mRNA levels, X-inactivation ratio, and CGG repeats seems to be similar both in women with POF and in those without: in women with POF, the effect of the CGG repeats on the mRNA levels was statistically significant (P = 0.0437), but in women without POF, it was not (P = 0.0724). Moreover, we confirmed previous results on the nonlinear association between CGG repeat number and the manifestation of POF, showing that the likelihood of having POF was significantly higher with fewer than 100 CGG repeats compared with 100 or more CGG repeats (odds ratio = 13.09, P = 0.0240).

Conclusions: Our present work suggests that mRNA and X-inactivation studies in blood are not relevant in predicting POF in female premutation carriers of fragile X syndrome. However, having a permutation of fewer than 100 repeats could represent a significant risk of POF.
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http://dx.doi.org/10.1097/gme.0b013e3181647762DOI Listing
January 2009

Analysis of FMR1 gene expression in female premutation carriers using robust segmented linear regression models.

RNA 2007 May;13(5):756-62

Laboratorio de Genética Molecular, Hospital de Cruces, 48903 Baracaldo, Bizkaia, Spain.

Fragile X syndrome is caused by the absence or reduction of the fragile X mental retardation protein (FMRP) because FMR1 gene expression is reduced. Alleles with repeat sizes of 55-200 are classified as premutations, and it has been demonstrated that FMR1 expression is elevated in the premutation range. However, the majority of the studies reported were performed in males. We studied FMR1 expression in 100 female fragile X family members from the northern region of Spain using quantitative (fluorescence) real-time polymerase chain reaction. Of these 100 women, 19 had normal alleles, 19 were full mutation carriers, and 62 were premutation carriers. After confirming differences between the three groups of females, and increased levels of the FMR1 transcript among premutation carriers, we found that the relationship between mRNA levels and repeat size is nonlinear. These results were obtained using a novel methodology that, based on the size of the CGG repeats, allows us to find out the most probable threshold from which the relationship between CGG repeat number and mRNA levels changes. Using this approach, a significant positive correlation between CGG repeats and total mRNA levels has been found in the premutation range <100 CGG, but this correlation diminishes from 100 onward. However, when correcting by the X inactivation ratio, mRNA levels increase as the number of CGG repeats increases, and this increase is highly significant over 100 CGG. We suggest that due to skewed X inactivation, mRNA levels tend to normalize in females when the number of CGG repeats increases.
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http://dx.doi.org/10.1261/rna.206307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1852810PMC
May 2007

Gene symbol: MECP2. Disease: Rett syndrome (atypical).

Hum Genet 2005 Dec;118(3-4):547

Emory University School of Medicine, Department of Human Genetics, Atlanta, GA 30322, USA.

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December 2005