https://hdl.handle.net/11000/479 2026-05-06T13:41:16Z https://hdl.handle.net/11000/39861 Título : Selective Lis1 inactivation disrupts migration and positioning of cortical somatostatin interneurons Autor : Pombero, Ana; García-López, Raquel; Geijo-Barrientos, E; Martínez, S Resumen : One subtype of interneurons, classified by their neurochemical properties, are somatostatin-positive (SST+) interneurons, which express somatostatin along with GABA and form synapses with both pyramidal neurons and other interneurons. SST+ interneurons originate in the medial ganglionic eminence and migrate tangentially to the cortex, making them potentially vulnerable to gene mutations linked to neuronal migration disorders. The Lis1 gene (Pafah1b1) regulates dynein-mediated motility, mitosis, and microtubule organization. Mutations in Lis1 are associated with lissencephaly and cortical disorganization. To investigate its role, we developed a mouse model with Lis1 deletion specifically in SST+ interneurons. We studied the anatomical and developmental effects of this deletion, focusing on tangential migration during embryonic and early postnatal stages. We analyzed SST+ interneuron numbers in the cingulate cortex (anterior and retrosplenial regions) of young mutant mice (P30). Our findings show a reduction in SST+ interneurons in mutants compared to controls, indicating impaired migration and/or maturation. Further research is needed to uncover the mechanisms behind this reduction and to determine its functional implications. 2026-05-06T10:44:36Z https://hdl.handle.net/11000/39860 Título : Pericyte-Glioblastoma Cell Interaction: A Key Target to Prevent Glioblastoma Progression Autor : Pombero, Ana; Garcia-Lopez, Raquel; Martínez, Salvador Resumen : Multiple biological processes rely on direct intercellular interactions to regulate cell proliferation and migration in embryonic development and cancer processes. Tumor development and growth depends on close interactions between cancer cells and cells in the tumor microenvironment. During embryonic development, morphogenetic signals and direct cell contacts control cell proliferation, polarity, and morphogenesis. Cancer cells communicate with cells in the tumor niche through molecular signals and intercellular contacts, thereby modifying the vascular architecture and antitumor surveillance processes and consequently enabling tumor growth and survival. While looking for cell-to-cell signaling mechanisms that are common to both brain development and cancer progression, we have studied the infiltration process in glioblastoma multiforme (GBM), which is the most malignant primary brain tumor and with the worst prognosis. Cell-to-cell contacts, by means of filopodia-like structures, between GBM cells and brain pericytes (PCs) are necessary for adequate cell signaling during cancer infiltration; similarly, contacts between embryonic regions, via cytonemes, are required for embryo regionalization and development. This GBM-PC interaction provokes two important changes in the physiological function of these perivascular cells, namely, (i) vascular co-option with changes in cell contractility and vascular malformation, and (ii) changes in the PC transcriptome, modifying the microvesicles and protein secretome, which leads to the development of an immunosuppressive phenotype that promotes tumor immune tolerance. Moreover, the GTPase Cdc42 regulates cell polarity across organisms, from yeast to humans, playing a central role in GBM cell-PC interaction and maintaining vascular co-option. As such, a review of the molecular and cellular mechanisms underlying the development and maintenance of the physical interactions between cancer cells and PCs is of particular interest. 2026-05-06T10:43:28Z https://hdl.handle.net/11000/39847 Título : Pericytes Are Immunoregulatory Cells in Glioma Genesis and Progression Autor : Martinez-Morga, Marta; Garrigós, Daniel; Rodriguez-Montero, Elena; Pombero, Ana; García-Lopez, Raquel; Martínez, Salvador Resumen : Vascular co-option is a consequence of the direct interaction between perivascular cells, known as pericytes (PCs), and glioblastoma multiforme (GBM) cells (GBMcs). This process is essential for inducing changes in the pericytes' anti-tumoral and immunoreactive phenotypes. Starting from the initial stages of carcinogenesis in GBM, PCs conditioned by GBMcs undergo proliferation, acquire a pro-tumoral and immunosuppressive phenotype by expressing and secreting immunosuppressive molecules, and significantly hinder the activation of T cells, thereby facilitating tumor growth. Inhibiting the pericyte (PC) conditioning mechanisms in the GBM tumor microenvironment (TME) results in immunological activation and tumor disappearance. This underscores the pivotal role of PCs as a key cell in the TME, responsible for tumor-induced immunosuppression and enabling GBM cells to evade the immune system. Other cells within the TME, such as tumor-associated macrophages (TAMs) and microglia, have also been identified as contributors to this immunomodulation. In this paper, we will review the role of these three cell types in the immunosuppressive properties of the TME. Our conclusion is that the cellular heterogeneity of immunocompetent cells within the TME may lead to the misinterpretation of cellular lineage identification due to different reactive stages and the identification of PCs as TAMs. Consequently, novel therapies could be developed to disrupt GBM-PC interactions and/or PC conditioning through vascular co-option, thereby exposing GBMcs to the immune system. 2026-05-05T18:50:41Z https://hdl.handle.net/11000/39846 Título : Chaperone mediated autophagy is deficient in spinal motoneurons of ALS patients with TDP-43 proteinopathy Autor : Garrigos, Daniel; Martínez-Morga, Marta; Pombero, Ana; García-Lopez, Raquel; Pastor, Diego; Riquelme, Dolores; Blanquer Blanquer, Miguel; Iniesta, Francisca ; Valdor, Rut; Geijo-Barrientos, Emilio; Hargus, Gunnar; Moraleda, Jose M.; Martínez, Salvador Resumen : Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease characterized by the selective loss of motor neurons (MNs), ultimately resulting in paralysis and respiratory failure within 3 to 5 years of onset. Fewer than 10% of ALS cases are familial (fALS), while the vast majority are sporadic (sALS) with an unknown etiology. A pathological hallmark of ALS is the accumulation of misfolded TDP-43 protein aggregates within MNs. Although TDP-43 is known to be degraded via chaperone-mediated autophagy (CMA), the status of CMA activity in sALS has not been previously explored. To investigate this, we analyzed CMA in human spinal cord tissue by assessing the expression of LAMP2A, a key lysosomal receptor and marker of CMA activity. In control samples, spinal cord MNs exhibited robust LAMP2A expression. In contrast, MNs from sALS patients showed a marked reduction in LAMP2A levels, coinciding with the presence of TDP-43 pathology. Notably, analysis of LC3, a marker of macroautophagy, revealed no significant differences in expression between control and sALS MNs. Interestingly, MNs within the Onuf’s nucleus, a population known to be resistant to degeneration in ALS, retained normal LAMP2A expression and did not exhibit TDP-43 aggregation in sALS cases. These findings demonstrated that CMA is essential for the clearance of TDP-43 in spinal cord MNs and that its dysfunction may contribute to the pathogenesis of sALS. Furthermore, the high dependence of spinal cord MNs on CMA activity may underlie their selective vulnerability to degeneration when CMA is impaired, and highlight CMA enhancement as a promising therapeutic strategy to restore proteostasis and prevent MN degeneration in ALS. 2026-05-05T18:48:02Z https://hdl.handle.net/11000/39845 Título : Interneuron Heterotopia in the Lis1 Mutant Mouse Cortex Underlies a Structural and Functional Schizophrenia-Like Phenotype Autor : Garcia-Lopez, Raquel; Pombero, Ana; Estirado, Alicia; Geijo-Barrientos, Emilio; Martinez, Salvador Resumen : LIS1 is one of the principal genes related to Type I lissencephaly, a severe human brain malformation characterized by an abnormal neuronal migration in the cortex during embryonic development. This is clinically associated with epilepsy and cerebral palsy in severe cases, as well as a predisposition to developing mental disorders, in cases with a mild phenotype. Although genetic variations in the LIS1 gene have been associated with the development of schizophrenia, little is known about the underlying neurobiological mechanisms. We have studied how the Lis1 gene might cause deficits associated with the pathophysiology of schizophrenia using the Lis1/sLis1 murine model, which involves the deletion of the first coding exon of the Lis1 gene. Homozygous mice are not viable, but heterozygous animals present abnormal neuronal morphology, cortical dysplasia, and enhanced cortical excitability. We have observed reduced number of cells expressing GABA-synthesizing enzyme glutamic acid decarboxylase 67 (GAD67) in the hippocampus and the anterior cingulate area, as well as fewer parvalbumin-expressing cells in the anterior cingulate cortex in Lis1/sLis1 mutants compared to control mice. The cFOS protein expression (indicative of neuronal activity) in Lis1/sLis1 mice was higher in the medial prefrontal (mPFC), perirhinal (PERI), entorhinal (ENT), ectorhinal (ECT) cortices, and hippocampus compared to control mice. Our results suggest that deleting the first coding exon of the Lis1 gene might cause cortical anomalies associated with the pathophysiology of schizophrenia. 2026-05-05T18:45:38Z https://hdl.handle.net/11000/39844 Título : Abnormalities in Cortical GABAergic Interneurons of the Primary Motor Cortex Caused by Lis1 (Pafah1b1) Mutation Produce a Non-drastic Functional Phenotype Autor : Domínguez-Sala, Eduardo; Valdés-Sánchez, L; Canals, V; Reiner, O; Pombero, Ana; García-López, R; Estirado, A; Pastor, D; Geijo-Barrientos, E; Martínez, S Resumen : LIS1 (PAFAH1B1) plays a major role in the developing cerebral cortex, and haploinsufficient mutations cause human lissencephaly type 1. We have studied morphological and functional properties of the cerebral cortex of mutant mice harboring a deletion in the first exon of the mouse Lis1 (Pafah1b1) gene, which encodes for the LisH domain. The Lis1/sLis1 animals had an overall unaltered cortical structure but showed an abnormal distribution of cortical GABAergic interneurons (those expressing calbindin, calretinin, or parvalbumin), which mainly accumulated in the deep neocortical layers. Interestingly, the study of the oscillatory activity revealed an apparent inability of the cortical circuits to produce correct activity patterns. Moreover, the fast spiking (FS) inhibitory GABAergic interneurons exhibited several abnormalities regarding the size of the action potentials, the threshold for spike firing, the time course of the action potential after-hyperpolarization (AHP), the firing frequency, and the frequency and peak amplitude of spontaneous excitatory postsynaptic currents (sEPSC's). These morphological and functional alterations in the cortical inhibitory system characterize the Lis1/sLis1 mouse as a model of mild lissencephaly, showing a phenotype less drastic than the typical phenotype attributed to classical lissencephaly. Therefore, the results described in the present manuscript corroborate the idea that mutations in some regions of the Lis1 gene can produce phenotypes more similar to those typically described in schizophrenic and autistic patients and animal models. 2026-05-05T18:43:45Z https://hdl.handle.net/11000/39241 Título : Mutations in the microRNA complementarity site of the INCURVATA4 gene perturb meristem function and adaxialize lateral organs in arabidopsis Autor : Ochando, Isabel; Jover-Gil, Sara; Ripoll, Juan-José; Candela, Héctor; Vera, Antonio; Ponce, María Rosa; Martínez-Laborda, Antonio; Micol, José Luis Resumen : Here, we describe how the semidominant, gain-of-function icu4-1 and icu4-2 alleles of the INCURVATA4 (ICU4) gene alter leaf phyllotaxis and cell organization in the root apical meristem, reduce root length, and cause xylem overgrowth in the stem. The ICU4 gene was positionally cloned and found to encode the ATHB15 transcription factor, a class III homeodomain/leucine zipper family member, recently named CORONA. The icu4-1 and icu4-2 alleles bear the same point mutation that affects the microRNA complementarity site of ICU4 and is identical to those of several semidominant alleles of the class III homeodomain/leucine zipper family members PHABULOSA and PHAVOLUTA. The icu4-1 and icu4-2 mutations significantly increase leaf transcript levels of the ICU4 gene. The null hst-1 allele of the HASTY gene, which encodes a nucleocytoplasmic transporter, synergistically interacts with icu4-1, the double mutant displaying partial adaxialization of rosette leaves and carpels. Our results suggest that the ICU4 gene has an adaxializing function and that it is down-regulated by microRNAs that require the HASTY protein for their biogenesis. 2026-02-12T15:02:12Z https://hdl.handle.net/11000/39240 Título : Common regulatory networks in leaf and fruit patterning revealed by mutations in the Arabidopsis ASYMMETRIC LEAVES1 gene Autor : Alonso-Cantabrana, Hugo; Ripoll, Juan José; Ochando, Isabel; Vera, Antonio; Ferrándiz, Cristina; Martínez-Laborda, Antonio Resumen : Carpels and leaves are evolutionarily related organs, as the former are thought to be modified leaves. Therefore, developmental pathways that play crucial roles in patterning both organs are presumably conserved. In leaf primordia of Arabidopsis thaliana, the ASYMMETRIC LEAVES1 (AS1) gene interacts with AS2 to repress the class I KNOTTED1-like homeobox (KNOX) genes BREVIPEDICELLUS (BP), KNAT2 and KNAT6, restricting the expression of these genes to the meristem. In this report, we describe how AS1, presumably in collaboration with AS2, patterns the Arabidopsis gynoecium by repressing BP, which is expressed in the replum and valve margin, interacts in the replum with REPLUMLESS (RPL), an essential gene for replum development, and positively regulates the expression of this gene. Misexpression of BP in the gynoecium causes an increase in replum size, while the valve width is slightly reduced, and enhances the effect of mutations in FRUITFULL (FUL), a gene with an important function in valve development. Altogether, these findings strongly suggest that BP plays a crucial role in replum development. We propose a model for pattern formation along the mediolateral axis of the ovary, whereby three domains (replum, valve margin and valve) are specified by the opposing gradients of two antagonistic factors, valve factors and replum factors, the class I KNOX genes working as the latter. 2026-02-12T14:55:57Z https://hdl.handle.net/11000/39239 Título : Clinical and molecular characterization of a patient with a combination of a deletion and a duplication of 22q13 using array CGH Autor : Ochando, Isabel; Urbano, Antonio; Rubio, Juana; Rueda, Joaquin Resumen : Phelan-McDermid syndrome is caused by the loss of terminal regions of different sizes at 22q13. There is a wide range of severity of symptoms in patients with a 22q13 deletion, but these patients usually show neonatal hypotonia, global developmental delay, and dysmorphic traits. We carried out a clinical and molecular characterization of a patient with neonatal hypotonia and dysmorphic features. Array-based comparative genomic hybridization showed an 8.24 Mb terminal deletion associated with a 0.20 Mb duplication. Characterization of patients with Phelan-McDermid syndrome both clinically and at the molecular level allows genotype-phenotype correlations that provide clues to help elucidate the clinical implications. 2026-02-12T14:48:43Z https://hdl.handle.net/11000/39238 Título : Alteration of the shoot radial pattern in Arabidopsis thaliana by a gain-of-function allele of the class III HD-Zip gene INCURVATA4 Autor : Ochando, Isabel; Gonzalez-Reig, Santiago; Ripoll, Juan José; Vera, Antonio; Martínez-Laborda, Antonio Resumen : Class III HD-Zip (HD-Zip III) family genes play key roles in a number of fundamental developmental programs in Arabidopsis thaliana, such as embryo patterning, meristem initiation and homeostasis, lateral organ polarity and vascular development. Semidominant gain-of-function alleles of the HD-Zip III genes PHABULOSA (PHB), PHAVOLUTA (PHV) and REVOLUTA (REV) disrupt the negative regulation of these genes by a mechanism of microRNA interference. We provide evidence that the gain-of-function icu4-1 allele of INCURVATA4, a gene encoding the HD-Zip III transcription factor ATHB15/CORONA (CNA), stimulates the production of vascular tissues, supporting a role for ICU4 in promoting vascular development. Occasionally, homozygous mutants for this allele show a reduced number of thick shoot vascular bundles, although normal collateral polarity remains unchanged. Genetic analysis of icu4-1 and phb-1D, a gain-of-function allele of the related PHB gene, revealed antagonism in lateral organ polarity between both mutations and a synergistic interaction in shoots, with transformation of the polarized collateral bundles into a radialized amphivasal pattern. These results indicate that the precise regulation of HD-Zip III genes confers positional information which is required to establish the number and pattern of vascular bundles in the stem. In addition, we present results that suggest an interaction between ICU4 function and auxin signaling. 2026-02-12T14:42:48Z