Perez-Mediavilla, L.A. (Luis Alberto)
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- Overexpression of wild-type human APP in mice causes cognitive déficits and pathological features unrelated to Abeta levels(Elsevier, 2009-03) Frechilla, D. (Diana); Perez-Mediavilla, L.A. (Luis Alberto); Salazar-Colocho, P. (Pablo); Simon, A.M. (Ana María); Cuadrado-Tejedor, M. (Mar); Schiapparelli, L. (Lucio); Rio, J. (Joaquín) del; Raquel; Escribano, L. (Luis)Transgenic mice expressing mutant human amyloid precursor protein (APP) develop an age-dependent amyloid pathology and memory deficits, but no overt neuronal loss. Here, in mice overexpressing wild-type human APP (hAPPwt) we found an early memory impairment, particularly in the water maze and to a lesser extent in the object recognition task, but β-amyloid peptide (Aβ42) was barely detectable in the hippocampus. In these mice, hAPP processing was basically non-amyloidogenic, with high levels of APP carboxy-terminal fragments, C83 and APP intracellular domain. A tau pathology with an early increase in the levels of phosphorylated tau in the hippocampus, a likely consequence of enhanced ERK1/2 activation, was also observed. Furthermore, these mice presented a loss of synapse-associated proteins: PSD95, AMPA and NMDA receptor subunits and phosphorylated CaMKII. Importantly, signs of neurodegeneration were found in the hippocampal CA1 subfield and in the entorhinal cortex that were associated to a marked loss of MAP2 immunoreactivity. Conversely, in mice expressing mutant hAPP, high levels of Aβ42 were found in the hippocampus, but no signs of neurodegeneration were apparent. The results support the notion of Aβ- independent pathogenic pathways in Alzheimer's disease.
- Maternal imprinting on cognition markers of wild type and transgenic Alzheimer's disease model mice(Nature Research, 2018) Perez-Mediavilla, L.A. (Luis Alberto); Zamarbide-González, M. (Marta); Franco, R. (Rafael); Gil-Bea, F.J. (Francisco J.); Martinez-Pinilla, E. (Eva); Bannenberg, P. (Paul); Sandoval, J. (Juan)The risk of suffering from Alzheimer’s disease (AD) is higher in individuals from AD-affected mothers. The purpose of this investigation was to study whether maternal transmission might produce AD-related alterations in progenies of mice that do not have any genotypic alteration. We used cognitively-intact mothers harbouring in heterozygosity the transgene for overexpressing the Swedish double mutant version of the human amyloid precursor protein (hAβPPswe). The phenotype of the offspring with or without the transgene resulting from crossing young Tg2576 females with wild-type males were compared with those of the offspring resulting from crossing wild-type females with Tg2576 males. The hAβPPswe-bearing offspring from Tg2576 mothers showed an aggravated AD-like phenotype. Remarkably, cognitive, immunohistochemical and some biochemical features displayed by Tg2576 heterozygous mice were also found in wild-type animals generated from Tg2576 females. This suggests the existence of a maternal imprinting in the wild-type offspring that confers a greater facility to launch an AD-like neurodegenerative cascade. Such progeny, lacking any mutant amyloid precursor protein, constitutes a novel model to study maternal transmission of AD and, even more important, to discover early risk markers that predispose to the development of AD.
- Rosiglitazone Rescues Memory Impairment in Alzheimer's Transgenic Mice: Mechanisms Involving a Reduced Amyloid and Tau Pathology(NATURE PUBLISHING GROUP, 2010-03) Frechilla, D. (Diana); Perez-Mediavilla, L.A. (Luis Alberto); Ricobaraza, A. (Ana); Gimeno, E. (Esther); Garcia-Osta, A. (Ana); Simon, A.M. (Ana María); Cuadrado-Tejedor, M. (Mar); Rio, J. (Joaquín) del; Raquel; Escribano, L. (Luis)Clinical studies suggest that agonists at peroxisome proliferator-activated receptor gamma (PPARγ) may exert beneficial effects in patients with mild-to-moderate Alzheimer's disease (AD), but the mechanism for the potential therapeutic interest of this class of drugs has not yet been elucidated. Here, in mice overexpressing mutant human amyloid precursor protein, we found that chronic treatment with rosiglitazone, a high-affinity agonist at PPARγ, facilitated β-amyloid peptide (Aβ) clearance. Rosiglitazone not only reduced Aβ burden in the brain but, importantly, almost completely removed the abundant amyloid plaques observed in the hippocampus and entorhinal cortex of 13-month-old transgenic mice. In the hippocampus, neuropil threads containing phosphorylated tau, probably corresponding to dystrophic neurites, were also decreased by the drug. Rosiglitazone switched on the activated microglial phenotype, promoting its phagocytic ability, reducing the expression of proinflammatory markers and inducing factors for alternative differentiation. The decreased amyloid pathology may account for the reduction of p-tau-containing neuropil threads and for the rescue of impaired recognition and spatial memory in the transgenic mice. This study provides further insights into the mechanisms for the beneficial effect of rosiglitazone in AD patients.
- Enhanced expression of the voltage-dependent anion channel 1 (VDAC1) in Alzheimer's disease transgenic mice: an insight into the pathogenic effects of amyloid-β(IOS Press, 2011) Frechilla, D. (Diana); Perez-Mediavilla, L.A. (Luis Alberto); Cabodevilla, F. (Felipe); Vilariño, M. (Marcos); Cuadrado-Tejedor, M. (Mar); Rio, J. (Joaquín) delThe mitochondrial voltage-dependent anion channel 1 (VDAC1) is involved in the release of apoptotic proteins with possible relevance in Alzheimer's disease (AD) neuropathology. Through proteomic analysis followed by Western blotting and immunohistochemical techniques, we have found that VDAC1 is overexpressed in the hippocampus from amyloidogenic AD transgenic mice models. VDAC1 was also overexpressed in postmortem brain tissue from AD patients at an advanced stage of the disease. Interestingly, amyloid-β (Aβ) soluble oligomers were able to induce upregulation of VDAC1 in a human neuroblastoma cell line, further supporting a correlation between Aβ levels and VDAC1 expression. In hippocampal extracts from transgenic mice, a significant increase was observed in the levels of VDAC1 phosphorylated at an epitope that is susceptible to phosphorylation by glycogen synthase kinase-3β, whose activity was also increased. The levels of hexokinase I (HXKI), which interacts with VDAC1 and affects its function, were decreased in mitochondrial samples from AD models. Since phospho-VDAC and reduced HXKI levels favors a VDAC1 conformational state more prone to the release proapoptotic factors, regulation of the function of this channel may be a promising therapeutic approach to combat AD.
- Early Changes in Hippocampal Eph Receptors Precede the Onset of Memory Decline in Mouse Models of Alzheimer’s Disease(IOS Press, 2009-01-22) Frechilla, D. (Diana); Avila, J. (Jesús); Perez-Mediavilla, L.A. (Luis Alberto); Ricobaraza, A. (Ana); Simon, A.M. (Ana María); Cuadrado-Tejedor, M. (Mar); Schiapparelli, L. (Lucio); Rio, J. (Joaquín) del; Raquel; Escribano, L. (Luis)Abstract. Synapse loss occurs early in Alzheimer’s disease (AD) and is considered the best pathological correlate of cognitive decline. Ephrins and Eph receptors are involved in regulation of excitatory neurotransmission and play a role in cytoskeleton remodeling. We asked whether alterations in Eph receptors could underlie cognitive impairment in an AD mouse model overexpressing human amyloid-β protein precursor (hAβPP) with familial mutations (hAβPPswe-ind mice). We found that EphA4 and EphB2 receptors were reduced in the hippocampus before the development of impaired object recognition and spatial memory. Similar results were obtained in another line of transgenic AβPP mice, Tg2576. A reduction in Eph receptor levels was also found in postmortem hippocampal tissue from patients with incipient AD. At the time of onset of memory decline in hAβPPswe-ind mice, no change in surface expression of AMPA or NMDA receptor subunits was apparent, but we found changes in Eph-receptor downstream signaling, in particular a decrease in membrane-associated phospho-cofilin levels that may cause cytoskeletal changes and disrupted synaptic activity. Consistent with this finding, Eph receptor activation in cell culture increased phospho-cofilin levels. The results suggest that alterations in Eph receptors may play a role in synaptic dysfunction in the hippocampus leading to cognitive impairment in a model of AD.
- Inducible nitric oxide synthase in human lymphomononuclear cells activated by synthetic peptides derived from extracellular matrix proteins.(Elsevier, 1995) Lopez-Moratalla, N. (Natalia); Perez-Mediavilla, L.A. (Luis Alberto); Montuenga-Badia, L.M. (Luis M.); Calonge-Domínguez, M. (María); Santiago, E. (Esteban); Lopez-Zabalza, M.J. (María Jesús)Synthetic peptides with sequences present in extracellular matrix proteins are capable of causing the expression of the inducible form of nitric oxide synthase (iNOS), detected by immunocytochemistry, and the release of NO by human lymphomononuclear cells incubated in their presence. Active peptides are 15-mers containing a characteristic 2-6-11 motif in which the amino acid residue at position 2 is Leu, Ile, Val, Gly, Ala or Lys; the residue at position 6 is always Pro; and residue 11 is Glu or Asp. The induction of iNOS in human monocytes and macrophages could be involved in the cytotoxicity against tumor cell lines also elicited by these peptides.
- Phenyl acyl acids attenuate the unfolded protein response in tunicamycin-treated neuroblastoma cells(2013) Perez-Mediavilla, L.A. (Luis Alberto); Ricobaraza, A. (Ana); Zamarbide-González, M. (Marta); Aragón-Amonárriz, T. (Tomás); Franco, R. (Rafael); Martinez-Pinilla, E. (Eva)
- Activation of human T helper 1 and DNAase expression in CD4+ T cells induced by short immunomodulating peptides.(Elsevier, 1994) Lopez-Moratalla, N. (Natalia); Perez-Mediavilla, L.A. (Luis Alberto); Migliacio, M. (Marco); Santiago, E. (Esteban); Lopez-Zabalza, M.J. (María Jesús)Activation of human T helper 1 cells took place when lymphomononuclear cells from healthy donors were incubated in the presence of short synthetic peptides encompassing sequences present in extracellular matrix proteins. Active peptides conformed to a common structural pattern ("2-6-11 motif") [N.López-Moratalla et al., Biochem. Biophys. Acta (1994) 1221, 153-158] conferring immunomodulating properties. The release of IL-2 and IFN gamma, as well as LAK and NK-dependent cytotoxicity induced by these peptides, could be blocked by anti-HLA-DR antibody. Activated CD4+ cells isolated from the mixed incubated population contained secretion granules with DNAase activity. These results suggest that these immunomodulating peptides presented by HLA-II play a key role in the differentiation of CD4+ T cells towards a Th1 functional phenotype.
- Accelerated amyloid deposition, neurofibrillary degeneration and neuronal loss in double mutant APP/tau transgenic mice(Elsevier, 2005) Ortiz, L. (Lourdes); Gomez-Isla, T. (Teresa); Avila, J. (Jesús); Perez-Mediavilla, L.A. (Luis Alberto); Ramos, P. (Pilar); Catena, S. (Silvia); Cabodevilla, F. (Felipe); Perez, M. (Mar); Samaranch, L. (Lluis); Ribe, E. (Elena M.); Ferrer, I. (Isidro); Nieto, M. (María); Puig, B. (Berta); Moran, M.A. (María Asunción); Cuadrado-Tejedor, M. (Mar); Sesma, T. (Teresa); Gich, I. (Ignasi); Sanchez, B. (Belén); Lim, F. (Filip)Even though the idea that amyloid beta peptide accumulation is the primary event in the pathogenesis of Alzheimer's disease has become the leading hypothesis, the causal link between aberrant amyloid precursor protein processing and tau alterations in this type of dementia remains controversial. We further investigated the role of beta-amyloid production/deposition in tau pathology and neuronal cell death in the mouse brain by crossing Tg2576 and VLW lines expressing human mutant amyloid precursor protein and human mutant tau, respectively. The resulting double transgenic mice showed enhanced amyloid deposition accompanied by neurofibrillary degeneration and overt neuronal loss in selectively vulnerable brain limbic areas. These findings challenge the idea that tau pathology in Alzheimer's disease is merely a downstream effect of amyloid production/deposition and suggest that reciprocal interactions between beta-amyloid and tau alterations may take place in vivo.
- Early-onset molecular derangements in the olfactory bulb of Tg2576 mice: Novel insights into the stress-responsive olfactory kinase dynamics in alzheimer’s disease(Frontiers Media SA, 2019) Perez-Mediavilla, L.A. (Luis Alberto); Palomino, M. (Maialen); González-Morales, A. (Andrea); Ferrer, I. (Isidro); Fernandez-Irigoyen, J. (Joaquín); Gómez-Ochoa, M. (Marta); Zelaya, M.V. (María Victoria); Lachén-Montes, M. (Mercedes); Santamaria, E. (Enrique); Ausin, K. (Karina)The olfactory bulb (OB) is the first processing station in the olfactory pathway. Despite smell impairment, which is considered an early event in Alzheimer’s disease (AD), little is known about the initial molecular disturbances that accompany the AD development at olfactory level. We have interrogated the time-dependent OB molecular landscape in Tg2576 AD mice prior to the appearance of neuropathological amyloid plaques (2-, and 6-month-old), using combinatorial omics analysis. The metabolic modulation induced by overproduction of human mutated amyloid precursor protein (APP) clearly differs between both time points. Besides the progressive perturbation of the APP interactome, functional network analysis unveiled an inverse regulation of downstream extracellular signal-regulated kinase (ERK1/2), and p38 mitogen-activated protein kinase (MAPK) routes in 2-month-old Tg2576 mice with respect to wild-type (WT) mice. In contrast, Akt and MAPK kinase 4 (SEK1)/ stress-activated protein kinase (SAPK) axis were parallel activated in the OB of 6-months-old-Tg2576 mice. Furthermore, a survival kinome profiling performed during the aging process (2-, 6-, and 18-month-old) revealed that olfactory APP overexpression leads to changes in the activation dynamics of protein kinase A (PKA), and SEK1/MKK4-SAPK/JNK between 6 and 18 months of age, when memory deficits appear and AD pathology is well established in transgenic mice. Interestingly, both olfactory pathways were differentially activated in a stage-dependent manner in human sporadic AD subjects with different neuropathological grading. Taken together, our data reflect the early impact of mutated APP on the OB molecular homeostasis, highlighting the progressive modulation of specific signaling pathways during the olfactory amyloidogenic pathology