Cajal Institute

Madrid, Spain

Cajal Institute

Madrid, Spain
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Fernandez S.,CIBER ISCIII | Genis L.,CIBER ISCIII | Torres-Aleman I.,Cajal Institute
Oncogene | Year: 2014

Loss-of-function mutations in the phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome10) contribute to aberrant cell growth in part through upregulation of the mitogenic IGF-1/PI3 K/Akt pathway. In turn, this pathway exerts a homeostatic feedback over PTEN. Using mutagenesis analysis to explore a possible impact of this mutual control on astrocyte growth, we found that truncation of the C-terminal region of PTEN (Δ51) associates with a marked increase in NFκB activity, a transcription factor overactivated in astrocyte tumors. Whereas mutations of PTEN are considered to lead to a loss-of-function, PTENΔ51, a truncation that comprises a region frequently mutated in human gliomas, displayed a neomorphic (gain-of-function) activity that was independent of its phosphatase activity. This gain-of-function of PTENΔ51 includes stimulation of IGF-1 synthesis through protein kinase A activation of the IGF-1 promoter. Increased IGF-1 originates an autocrine loop that activates Akt and NFκB. Constitutive activation of NFκB in PTENΔ51-expressing astrocytes leads to aberrant cell growth; astrocytes expressing this mutant PTEN generate colonies in vitro and tumors in vivo. Mutations converting a tumor suppressor such as PTEN into a tumor promoter through a gain-of-function involving IGF-1 production may further our understanding of the role played by this growth factor in glioma growth and help us define druggable targets for personalized therapy. © 2014 Macmillan Publishers Limited.


Morillo S.M.,Cajal Institute | Abanto E.P.,Cajal Institute | Roman M.J.,Cajal Institute | Frade J.M.,Cajal Institute
Molecular and Cellular Biology | Year: 2012

Cumulative evidence indicates that activation of cyclin D-dependent kinase 4/6 (cdk4/6) represents a major trigger of cell cycle reentry and apoptosis in vertebrate neurons. We show here the existence of another mechanism triggering cell cycle reentry in differentiating chick retinal neurons (DCRNs), based on phosphorylation of E2F4 by p38MAPK. We demonstrate that the activation of p75NTR by nerve growth factor (NGF) induces nuclear p38MAPK kinase activity, which leads to Thr phosphorylation and subsequent recruitment of E2F4 to the E2F-responsive cdc2 promoter. Inhibition of p38MAPK, but not of cdk4/6, specifically prevents NGF-dependent cell cycle reentry and apoptosis in DCRNs. Moreover, a constitutively active form of chick E2F4 (Thr261Glu/Thr263Glu) stimulates G1/S transition and apoptosis, even after inhibition of p38MAPK activity. In contrast, a dominant-negative E2F4 form (Thr261Ala/Thr263Ala) prevents NGF-induced cell cycle reactivation and cell death in DCRNs. These results indicate that NGF-induced cell cycle reentry in neurons depends on the activation of a novel, cdk4/6-independent pathway that may participate in neurodegeneration. © 2012, American Society for Microbiology.


Sanchez-Blazquez P.,Cajal Institute | Rodriguez-Munoz M.,Cajal Institute | Vicente-Sanchez A.,Cajal Institute | Garzon J.,Cajal Institute
Antioxidants and Redox Signaling | Year: 2013

Aims: Overactivation of glutamate N-methyl-D-aspartate receptor (NMDAR) increases the cytosolic concentrations of calcium and zinc, which significantly contributes to neural death. Since cannabinoids prevent the NMDAR-mediated increase in cytosolic calcium, we investigated whether they also control the rise of potentially toxic free zinc ions, as well as the processes implicated in this phenomenon. Results: The cannabinoid receptors type 1 (CNR1) and NMDARs are cross-regulated in different regions of the nervous system. Cannabinoids abrogated the stimulation of the nitric oxide-zinc pathway by NMDAR, an effect that required the histidine triad nucleotide-binding protein 1 (HINT1). Conversely, NMDAR antagonism reduced the analgesia promoted by the CNR1 agonist WIN55,212-2 and impaired its capacity to internalize CNR1s. At the cell surface, CNR1s co-immunoprecipitated with the NR1 subunits of NMDARs, an association that diminished after the administration of NMDA in vivo or as a consequence of neuropathic overactivation of NMDARs, both situations in which cannabinoids do not control NMDAR activity. Under these circumstances, inhibition of protein kinase A (PKA) restored the association between CNR1s and NR1 subunits, and cannabinoids regained control over NMDAR activity. Notably, CNR1 and NR1 associated poorly in HINT1-/- mice, in which there was little cross-regulation between these receptors. Innovation: The CNR1 can regulate NMDAR function when the receptor is coupled to HINT1. Thus, internalization of CNR1s drives the co-internalization of the NR1 subunits, neutralizing the overactivation of NMDARs. Conclusion: Cannabinoids require the HINT1 protein to counteract the toxic effects of NMDAR-mediated NO production and zinc release. This study situates the HINT1 protein at the forefront of cannabinoid protection against NMDAR-mediated brain damage. © 2013, Mary Ann Liebert, Inc.


Bolos M.,Cajal Institute | Fernandez S.,Cajal Institute | Torres-Aleman I.,Cajal Institute
Journal of Biological Chemistry | Year: 2010

Reduced brain input of serum insulin-like growth factor I (IGF-I), a potent neurotrophic peptide, may be associated with neurodegenerative processes. Thus, analysis of the mechanisms involved in passage of blood-borne IGF-I into the brain may shed light onto pathological mechanisms in neurodegeneration and provide new drug targets. A site of entrance of serum IGF-I into the brain is the choroid plexus. The transport mechanism for IGF-I in this specialized epithelium involves the IGF-I receptor and the membrane multicargo transporter megalin/LRP2. We have now analyzed this process in greater detail and found that the IGF-I receptor interacts with the transmembrane region of megalin, whereas the perimembrane domain of megalin is required for IGF-I internalization. Furthermore, a GSK3 site within the Src homology 3 domain of the C-terminal region of megalin is a key regulator of IGF-I transport. Thus, inhibition of GSK3 markedly increased internalization of IGF-I, whereas mutation of this GSK3 site abrogated this increase. Notably, oral administration of a GSK3 inhibitor to adult wild-type mice or to amyloid precursor protein/presenilin 1 mice modeling Alzheimer amyloidosis significantly increased brain IGF-I content. These results indicate that pharmacological modulation of IGF-I transport by megalin may be used to increase brain availability of serum IGF-I. Interestingly, GSK3 inhibitors such as those under development to treat Alzheimer disease may show therapeutic efficacy in part by increasing brain IGF-I levels, an effect already reported for other neuroprotective compounds. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.


Lopez-Sanchez N.,Cajal Institute | Frade J.M.,Cajal Institute
Journal of Neuroscience | Year: 2013

A subpopulation of chick retinal projection neurons becomes tetraploid during development, an event prevented by blocking antibodies against p75 neurotrophin receptor (p75NTR).Wehave used an optimized flow cytometric assay, based on the analysis of unfixed brain cell nuclei, to study whether p75NTR-dependent neuronal tetraploidization takes place in the cerebral cortex, giving rise to projection neurons as well. We show that 3% of neurons in both murine neocortex and chick telencephalic derivatives are tetraploid, and that in the mouse ~85%of these neurons express the immediate early genes Erg-1 and c-Fos, indicating that they are functionally active. Tetraploid cortical neurons (65-80%) express CTIP2, a transcription factor specific for subcortical projection neurons in the mouse neocortex. During the period in which these neurons are born, p75NTR- is detected in differentiating neurons undergoing DNA replication. Accordingly, p75NTRdeficient mice contain a reduced proportion of both NeuN and CTIP2-positive neocortical tetraploid neurons, thus providing genetic evidence for the participation of p75NTR- in the induction of neuronal tetraploidy in the mouse neocortex. In the striatum tetraploidy is mainly associated with long-range projection neurons as well since ~80% of tetraploid neurons in this structure express calbindin, a marker of neostriatal-matrix spiny neurons, known to establish long-range projections to the substantia nigra and globus pallidus. In contrast, only 20% of tetraploid cortical neurons express calbindin, which is mainly expressed in layers II-III, where CTIP2 is absent.We conclude that tetraploidy mainly affects long-range projection neurons, being facilitated by p75NTR in the neocortex. © 2013 the authors.


Fernandez A.M.,Cajal Institute | Torres-Aleman I.,Cajal Institute
Nature Reviews Neuroscience | Year: 2012

Central and peripheral insulin-like peptides (ILPs), which include insulin, insulin-like growth factor 1 (IGF1) and IGF2, exert many effects in the brain. Through their actions on brain growth and differentiation, ILPs contribute to building circuitries that subserve metabolic and behavioural adaptation to internal and external cues of energy availability. In the adult brain each ILP has distinct effects, but together their actions ultimately regulate energy homeostasis - they affect nutrient sensing and regulate neuronal plasticity to modulate adaptive behaviours involved in food seeking, including high-level cognitive operations such as spatial memory. In essence, the multifaceted activity of ILPs in the brain may be viewed as a system organization involved in the control of energy allocation. © 2012 Macmillan Publishers Limited. All rights reserved.


Sanchez-Blazquez P.,Cajal Institute | Rodriguez-Munoz M.,Cajal Institute | Bailon C.,Cajal Institute | Garzon J.,Cajal Institute
Antioxidants and Redox Signaling | Year: 2012

Aims: Morphine signaling via the μ-opioid receptor (MOR) is coupled to redox-dependent zinc release from endogenous stores. Thus, MOR activation stimulates the complex formed by RGSZ2 (a regulator of G protein signaling) and neural nitric oxide synthase (nNOS) to produce NO, and to recruit PKCγ and Raf-1 in a zinc-dependent manner. Accordingly, we investigated whether redox regulation of zinc metabolism was unique to the MOR, or if it is a signaling mechanism shared by G-protein coupled receptors (GPCRs). Results: A physical interaction with the RGSZ2-nNOS complex was detected for the following GPCRs: neuropeptides, MOR and δ-opioid (DOR); biogenic amines, 5HT1A, 5HT2A, α2A, D1 and D2; acetylcholine, muscarinic M2 and M4; excitatory amino acid glutamate, mGlu2 and mGlu5; and derivatives of arachidonic acid (anandamide), CB1. Agonist activation of these receptors induced the release of zinc ions from the RGSZ2 zinc finger via a nNOS/NO-dependent mechanism, recruiting PKCγ and Raf-1 to the C terminus or the third internal loop of the GPCR. Innovation: A series of GPCRs share an unexpected mechanistic feature, the nNOS/NO-dependent regulation of zinc ion signaling via a redox mechanism. The RGSZ2 protein emerges as a potential redox zinc switch that converts NO signals into zinc signals, thereby able to modulate the function of redox sensor proteins like PKCγ or Raf-1. Conclusion: Redox mechanisms are crucial for the successful propagation of GPCR signals in neurons. Thus, dysfunctions of GPCR-regulated NO/zinc signaling may contribute to neurodegenerative and mood disorders such as Alzheimer's disease and depression. © 2012 Mary Ann Liebert, Inc.


Llorens-Martin M.,Cajal Institute | Tejeda G.S.,Cajal Institute | Trejo J.L.,Cajal Institute
Neuropsychopharmacology | Year: 2011

Physical-cognitive activity has long-lasting beneficial effects on the brain and on behavior. Environmental enrichment (EE) induces brain activity known to influence the behavior of mice, as measured in learned helplessness paradigms (forced swim test), and neurogenic cell populations in the hippocampal dentate gyrus. However, it is not completely clear whether the antidepressant and proneurogenic effects of EE are different in animals that are naive or pre-exposed to the stress inducing helplessness, and if this depends on the type of stressor. It also remains unclear whether differential effects are exerted on distinct neurogenic subpopulations. We found that EE has a protective effect in adult female mice (C57BL/6J) when exposed twice to the same stressor (forced swim test) but it has no influence on recovery. The repeated exposure to this stressor was analyzed together with the effects of EE on different neurogenic populations distinguished by age and differentiation state. Younger cells are more sensitive and responsive to the conditions, both the positive and negative effects. These results are relevant to identify the cell populations that are the targets of stress, depression, and enrichment, and that form part of the mechanism responsible for mood dysfunctions. © 2011 American College of Neuropsychopharmacology. All rights reserved.


Torres Aleman I.,Cajal Institute
Endocrinology and Metabolism Clinics of North America | Year: 2012

The previously undisputed neuroprotective role of insulin-like growth factor 1 (IGF-1) has been challenged by recent observations in IGF-1 receptor (IGF-1R) defective mutants. As new ligand-dependent and ligand-independent roles for IGF-1R are now emerging, new insights into the biologic role of brain IGF-1R and its connection with serum and brain IGF-1 function are urgently required. In the meantime, treatment of specific neurodegenerative diseases with IGF-1 may still be explored using adequate preclinical procedures. © 2012 Elsevier Inc.


Within a consortium, led by Oryzon, that will have a 1.3M USD aggregated budget BARCELONA, SPAIN and CAMBRIDGE, MA--(Marketwired - December 21, 2016) - Oryzon Genomics ( : ORY) (ISIN Code: ES0167733015), a public clinical-stage biopharmaceutical company leveraging epigenetics to develop therapies in diseases with strong unmet medical need, announced today that the Company will receive a new grant in the form of a loan with interest rate granted, from the Ministry of Economy and Competitiveness, Government of Spain and FEDER Funds from the European Union and included under the RETOS Collaboration 2016 program. Oryzon will receive approximately 0.8M USD (multiyear disbursements) for further development of its epigenetic inhibitors against inflammatory indications. This grant (RTC-2016-4955-1) will cover the partial funding of a project entitled "Epigenetic regulation of the inflammatory response" that is currently being carried out under the leadership of Oryzon in collaboration with various well renowned academic institutions such as the Cajal Institute (National Spanish Research Council, CSIC, Madrid), the López Neira Institute (CSIC, Granada), Bosch i Gimpera Foundation (University of Barcelona) and the Autonomous University of Barcelona. The project has a 33 month duration, starting April 1, 2016 and ending December 31, 2018, and the aggregated budget of the project is approximately 1.3M USD. The public institutions will receive a non-reimbursable grant to develop different activities to assess the potential of Oryzon's drugs on inflammatory diseases for a total amount exceeding 0.4 M USD. Carlos Buesa, President and Chief Executive Officer of Oryzon, commented: "This private-public consortium will set up useful tools and approaches to assess the therapeutic potential of LSD1 inhibitors and other epigenetic modulators in inflammatory and autoimmune diseases, a field that Oryzon is already exploring with ORY-2001, its first in class epigenetic program in Multiple Sclerosis. ORY-2001 is expected to finish Phase I in the next months." Founded in 2000 in Barcelona, Spain, Oryzon (ISIN Code: ES0167733015) is a clinical stage biopharmaceutical company considered as the European champion in Epigenetics. The company has one of the strongest portfolios in the field and a clinical asset already partnered with Roche. Oryzon's LSD1 program is currently covered by +20 patent families and has rendered two compounds in clinical trials. In addition, Oryzon has ongoing programs for developing inhibitors against other epigenetic targets. The company has a strong technological platform for biomarker identification and performs biomarker and target validation for a variety of malignant and neurodegenerative diseases. Oryzon's strategy is to develop first in class compounds against novel epigenetic targets through Phase II clinical trials, at which point it is decided on a case-by-case basis to either keep the development in-house or to partner or out-license the compound for late stage development and commercialization. The company has offices in Barcelona and Cambridge, Massachusetts. For more information, visit www.oryzon.com. This communication contains forward-looking information and statements about Oryzon Genomics, S.A., including financial projections and estimates and their underlying assumptions, statements regarding plans, objectives and expectations with respect to future operations, capital expenditures, synergies, products and services, and statements regarding future performance. Forward-looking statements are statements that are not historical facts and are generally identified by the words "expects", "anticipates", "believes", "intends", "estimates" and similar expressions. Although Oryzon Genomics, S.A. believes that the expectations reflected in such forward-looking statements are reasonable, investors and holders of Oryzon Genomics, S.A. shares are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of Oryzon Genomics, S.A., that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include those discussed or identified in the documents sent by Oryzon Genomics, S.A. to the Comisión Nacional del Mercado de Valores, which are accessible to the public. Forward-looking statements are not guarantees of future performance. The auditors of Oryzon Genomics, S.A, have not reviewed them. You are cautioned not to place undue reliance on the forward-looking statements, which speak only as of the date they were made. All subsequent oral or written forward-looking statements attributable to Oryzon Genomics, S.A. or any of its members, directors, officers, employees or any persons acting on its behalf are expressly qualified in their entirety by the cautionary statement above. All forward-looking statements included herein are based on information available to Oryzon Genomics, S.A. on the date hereof. Except as required by applicable law, Oryzon Genomics, S.A. does not undertake any obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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