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1.
Biochim Biophys Acta Mol Basis Dis ; 1870(5): 167187, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38653354

RESUMEN

Clinical relevance of miRNAs as biomarkers is growing due to their stability and detection in biofluids. In this, diagnosis at asymptomatic stages of Alzheimer's disease (AD) remains a challenge since it can only be made at autopsy according to Braak NFT staging. Achieving the objective of detecting AD at early stages would allow possible therapies to be addressed before the onset of cognitive impairment. Many studies have determined that the expression pattern of some miRNAs is dysregulated in AD patients, but to date, none has been correlated with downregulated expression of cellular prion protein (PrPC) during disease progression. That is why, by means of cross studies of miRNAs up-regulated in AD with in silico identification of potential miRNAs-binding to 3'UTR of human PRNP gene, we selected miR-519a-3p for our study. Then, in vitro experiments were carried out in two ways. First, we validated miR-519a-3p target on 3'UTR-PRNP, and second, we analyzed the levels of PrPC expression after using of mimic technology on cell culture. In addition, RT-qPCR was performed to analyzed miR-519a-3p expression in human cerebral samples of AD at different stages of disease evolution. Additionally, samples of other neurodegenerative diseases such as other non-AD tauopathies and several synucleinopathies were included in the study. Our results showed that miR-519a-3p overlaps with PRNP 3'UTR in vitro and promotes downregulation of PrPC. Moreover, miR-519a-3p was found to be up-regulated exclusively in AD samples from stage I to VI, suggesting its potential use as a novel label of preclinical stages of the disease.


Asunto(s)
Regiones no Traducidas 3' , Enfermedad de Alzheimer , Biomarcadores , MicroARNs , Proteínas Priónicas , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/diagnóstico , Proteínas Priónicas/genética , Proteínas Priónicas/metabolismo , Biomarcadores/metabolismo , Regiones no Traducidas 3'/genética , Femenino , Anciano , Masculino , Anciano de 80 o más Años , Proteínas PrPC/metabolismo , Proteínas PrPC/genética
2.
iScience ; 26(6): 106814, 2023 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-37235048

RESUMEN

Regeneration after a peripheral nerve injury still remains a challenge, due to the limited regenerative potential of axons after injury. While the endocannabinoid system (ECS) has been widely studied for its neuroprotective and analgesic effects, its role in axonal regeneration and during the conditioning lesion remains unexplored. In this study, we observed that a peripheral nerve injury induces axonal regeneration through an increase in the endocannabinoid tone. We also enhanced the regenerative capacity of dorsal root ganglia (DRG) neurons through the inhibition of endocannabinoid degradative enzyme MAGL or a CB1R agonist. Our results suggest that the ECS, via CB1R and PI3K-pAkt pathway activation, plays an important role in promoting the intrinsic regenerative capacity of sensory neurons after injury.

3.
Int J Mol Sci ; 24(7)2023 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-37047532

RESUMEN

Transcriptomics and phosphoproteomics were carried out in the cerebral cortex of B6.Cg-Mapttm1(EGFP)Klt (tau knockout: tau-KO) and wild-type (WT) 12 month-old mice to learn about the effects of tau ablation. Compared with WT mice, tau-KO mice displayed reduced anxiety-like behavior and lower fear expression induced by aversive conditioning, whereas recognition memory remained unaltered. Cortical transcriptomic analysis revealed 69 downregulated and 105 upregulated genes in tau-KO mice, corresponding to synaptic structures, neuron cytoskeleton and transport, and extracellular matrix components. RT-qPCR validated increased mRNA levels of col6a4, gabrq, gad1, grm5, grip2, map2, rab8a, tubb3, wnt16, and an absence of map1a in tau-KO mice compared with WT mice. A few proteins were assessed with Western blotting to compare mRNA expression with corresponding protein levels. Map1a mRNA and protein levels decreased. However, ß-tubulin III and GAD1 protein levels were reduced in tau-KO mice. Cortical phosphoproteomics revealed 121 hypophosphorylated and 98 hyperphosphorylated proteins in tau-KO mice. Deregulated phosphoproteins were categorized into cytoskeletal (n = 45) and membrane proteins, including proteins of the synapses and vesicles, myelin proteins, and proteins linked to membrane transport and ion channels (n = 84), proteins related to DNA and RNA metabolism (n = 36), proteins connected to the ubiquitin-proteasome system (UPS) (n = 7), proteins with kinase or phosphatase activity (n = 21), and 22 other proteins related to variegated pathways such as metabolic pathways, growth factors, or mitochondrial function or structure. The present observations reveal a complex altered brain transcriptome and phosphoproteome in tau-KO mice with only mild behavioral alterations.


Asunto(s)
Proteostasis , Proteínas tau , Ratones , Animales , Ratones Noqueados , Proteínas tau/genética , Proteínas tau/metabolismo , Neuronas/metabolismo , Corteza Cerebral/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo
4.
Eur J Med Chem ; 250: 115169, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36753881

RESUMEN

A set of twenty-five thioxanthene-9-one and xanthene-9-one derivatives, that were previously shown to inhibit cholinesterases (ChEs) and amyloid ß (Aß40) aggregation, were evaluated for the inhibition of tau protein aggregation. All compounds exhibited a good activity, and eight of them (5-8, 10, 14, 15 and 20) shared comparable low micromolar inhibitory potency versus Aß40 aggregation and human acetylcholinesterase (AChE), while inhibiting human butyrylcholinesterase (BChE) even at submicromolar concentration. Compound 20 showed outstanding biological data, inhibiting tau protein and Aß40 aggregation with IC50 = 1.8 and 1.3 µM, respectively. Moreover, at 0.1-10 µM it also exhibited neuroprotective activity against tau toxicity induced by okadoic acid in human neuroblastoma SH-SY5Y cells, that was comparable to that of estradiol and PD38. In preliminary toxicity studies, these interesting results for compound 20 are somewhat conflicting with a narrow safety window. However, compound 10, although endowed with a little lower potency for tau and Aß aggregation inhibition additionally demonstrated good inhibition of ChEs and rather low cytotoxicity. Compound 4 is also worth of note for its high potency as hBChE inhibitor (IC50 = 7 nM) and for the three order of magnitude selectivity versus hAChE. Molecular modelling studies were performed to explain the different behavior of compounds 4 and 20 towards hBChE. The observed balance of the inhibitory potencies versus the relevant targets indicates the thioxanthene-9-one derivatives as potential MTDLs for AD therapy, provided that the safety window will be improved by further structural variations, currently under investigation.


Asunto(s)
Enfermedad de Alzheimer , Neuroblastoma , Humanos , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Butirilcolinesterasa/metabolismo , Péptidos beta-Amiloides/metabolismo , Acetilcolinesterasa/metabolismo , Inhibidores de la Colinesterasa/química , Estructura Molecular , Relación Estructura-Actividad , Neuroblastoma/tratamiento farmacológico , Diseño de Fármacos , Simulación del Acoplamiento Molecular
5.
Neuroscience ; 518: 119-140, 2023 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-34757172

RESUMEN

The hippocampus of cases with neurofibrillary tangles (NFT) pathology classified as stages I-II, III-IV, and V-VI without comorbidities, and middle-aged (MA) individuals with no NFT pathology, were examined to learn about the composition of granulovacuolar degeneration (GVD). Our results confirm the presence of CK1-δ, p38-P Thr180/Tyr182, SAPK/JNK-P Thr183/Thr185, GSK-3α/ß-P Tyr279/Tyr216, and GSK-3ß Ser9 in the cytoplasmic granules in a subset of neurons of the CA1 and CA2 subfields of the hippocampus. Also, we identify the presence of PKA α/ß-P Thr197, SRC-P Tyr416, PAK1-P Ser199/Ser204, CAMK2A-P Tyr197, and PKCG-P Thr655 in cytoplasmic granules in cases with NFT pathology, but not in MA cases. Our results also confirm the presence of ß-catenin-P Ser45/Thr41, IREα-P Ser274, eIF2α-P Ser51, TDP-43-P Ser403-404 (but absent TDP-43), and ubiquitin in cytoplasmic granules. Other components of the cytoplasmic granules are MAP2-P Thr1620/1623, MAP1B-P Thr1265, ADD1-P Ser726, and ADD1/ADD1-P Ser726/Ser713, in addition to several tau species including 3Rtau, 4Rtau, and tau-P Ser262. The analysis of GVD at progressive stages of NFT pathology reveals the early appearance of phosphorylated kinases and proteins in cytoplasmic granules at stages I-II, before the appearance of pre-tangles and NFTs. Most of these granules are not surrounded by LAMP1-positive membranes. Markers of impaired ubiquitin-protesome system, abnormal reticulum stress response, and altered endocytic and autophagic pathways occur in a subpopulation of neurons containing cytoplasmic granules, and they appear later. These observations suggest early phosphorylation of kinases leading to their activation, and resulting in the abnormal phosphorylation of various substrates, including tau, as a main alteration at the first stages of GVD.


Asunto(s)
Enfermedad de Alzheimer , Ovillos Neurofibrilares , Humanos , Persona de Mediana Edad , Ovillos Neurofibrilares/metabolismo , Ovillos Neurofibrilares/patología , Enfermedad de Alzheimer/metabolismo , Fosforilación , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Proteínas tau/metabolismo , Degeneración Nerviosa/patología , Hipocampo/metabolismo , Proteínas de Unión al ADN/metabolismo , Ubiquitinas/metabolismo
6.
Neuroscience ; 518: 64-69, 2023 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-35525497

RESUMEN

Here we revisit tau protein aggregation at primary, secondary, tertiary and quaternary structures. In addition, the presence of non-aggregated tau protein, which has been recently discovered, is also commented on.


Asunto(s)
Microtúbulos , Proteínas tau , Proteínas tau/metabolismo , Microtúbulos/metabolismo
7.
Neuropsychopharmacology ; 48(2): 341-350, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36088492

RESUMEN

Peripheral inputs continuously shape brain function and can influence memory acquisition, but the underlying mechanisms have not been fully understood. Cannabinoid type-1 receptor (CB1R) is a well-recognized player in memory performance, and its systemic modulation significantly influences memory function. By assessing low arousal/non-emotional recognition memory in mice, we found a relevant role of peripheral CB1R in memory persistence. Indeed, the peripherally-restricted CB1R specific antagonist AM6545 showed significant mnemonic effects that were occluded in adrenalectomized mice, and after peripheral adrenergic blockade. AM6545 also transiently impaired contextual fear memory extinction. Vagus nerve chemogenetic inhibition reduced AM6545-induced mnemonic effect. Genetic CB1R deletion in dopamine ß-hydroxylase-expressing cells enhanced recognition memory persistence. These observations support a role of peripheral CB1R modulating adrenergic tone relevant for cognition. Furthermore, AM6545 acutely improved brain connectivity and enhanced extracellular hippocampal norepinephrine. In agreement, intra-hippocampal ß-adrenergic blockade prevented AM6545 mnemonic effects. Altogether, we disclose a novel CB1R-dependent peripheral mechanism with implications relevant for lengthening the duration of non-emotional memory.


Asunto(s)
Norepinefrina , Receptor Cannabinoide CB1 , Animales , Ratones , Adrenérgicos/farmacología , Encéfalo , Hipocampo , Norepinefrina/farmacología , Receptor Cannabinoide CB1/antagonistas & inhibidores
8.
Int J Mol Sci ; 23(24)2022 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-36555581

RESUMEN

Heterozygous hTau mice were used for the study of tau seeding. These mice express the six human tau isoforms, with a high predominance of 3Rtau over 4Rtau. The following groups were assessed: (i) non-inoculated mice aged 9 months (n = 4); (ii) Alzheimer's Disease (AD)-inoculated mice (n = 4); (iii) Globular Glial Tauopathy (GGT)-inoculated mice (n = 4); (iv) Pick's disease (PiD)-inoculated mice (n = 4); (v) control-inoculated mice (n = 4); and (vi) inoculated with vehicle alone (n = 2). AD-inoculated mice showed AT8-immunoreactive neuronal pre-tangles, granular aggregates, and dots in the CA1 region of the hippocampus, dentate gyrus (DG), and hilus, and threads and dots in the ipsilateral corpus callosum. GGT-inoculated mice showed unique or multiple AT8-immunoreactive globular deposits in neurons, occasionally extended to the proximal dendrites. PiD-inoculated mice showed a few loose pre-tangles in the CA1 region, DG, and cerebral cortex near the injection site. Coiled bodies were formed in the corpus callosum in AD-inoculated mice, but GGT-inoculated mice lacked globular glial inclusions. Tau deposits in inoculated mice co-localized active kinases p38-P and SAPK/JNK-P, thus suggesting active phosphorylation of the host tau. Tau deposits were absent in hTau mice inoculated with control homogenates and vehicle alone. Deposits in AD-inoculated hTau mice contained 3Rtau and 4Rtau; those in GGT-inoculated mice were mainly stained with anti-4Rtau antibodies, but a small number of deposits contained 3Rtau. Deposits in PiD-inoculated mice were stained with anti-3Rtau antibodies, but rare neuronal, thread-like, and dot-like deposits showed 4Rtau immunoreactivity. These findings show that tau strains produce different patterns of active neuronal seeding, which also depend on the host tau. Unexpected 3Rtau and 4Rtau deposits after inoculation of homogenates from 4R and 3R tauopathies, respectively, suggests the regulation of exon 10 splicing of the host tau during the process of seeding, thus modulating the plasticity of the cytoskeleton.


Asunto(s)
Enfermedad de Alzheimer , Enfermedad de Pick , Tauopatías , Humanos , Ratones , Animales , Ratones Transgénicos , Proteínas tau/genética , Proteínas tau/metabolismo , Encéfalo/metabolismo , Hipocampo/metabolismo
9.
Int J Mol Sci ; 23(19)2022 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-36232835

RESUMEN

Tauopathies are a group of neurodegenerative diseases characterized by the hyperphosphorylation and deposition of tau proteins in the brain. In Alzheimer's disease, and other related tauopathies, the pattern of tau deposition follows a stereotypical progression between anatomically connected brain regions. Increasing evidence suggests that tau behaves in a "prion-like" manner, and that seeding and spreading of pathological tau drive progressive neurodegeneration. Although several advances have been made in recent years, the exact cellular and molecular mechanisms involved remain largely unknown. Since there are no effective therapies for any tauopathy, there is a growing need for reliable experimental models that would provide us with better knowledge and understanding of their etiology and identify novel molecular targets. In this review, we will summarize the development of cellular models for modeling tau pathology. We will discuss their different applications and contributions to our current understanding of the "prion-like" nature of pathological tau.


Asunto(s)
Enfermedad de Alzheimer , Priones , Tauopatías , Enfermedad de Alzheimer/metabolismo , Encéfalo/metabolismo , Humanos , Priones/metabolismo , Tauopatías/metabolismo , Proteínas tau/metabolismo
10.
Front Immunol ; 13: 880647, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35911704

RESUMEN

While chemokines were originally described for their ability to induce cell migration, many studies show how these proteins also take part in many other cell functions, acting as adaptable messengers in the communication between a diversity of cell types. In the nervous system, chemokines participate both in physiological and pathological processes, and while their expression is often described on glial and immune cells, growing evidence describes the expression of chemokines and their receptors in neurons, highlighting their potential in auto- and paracrine signalling. In this study we analysed the role of nociception in the neuronal chemokinome, and in turn their role in axonal growth. We found that stimulating TRPV1+ nociceptors induces a transient increase in CCL21. Interestingly we also found that CCL21 enhances neurite growth of large diameter proprioceptors in vitro. Consistent with this, we show that proprioceptors express the CCL21 receptor CCR7, and a CCR7 neutralizing antibody dose-dependently attenuates CCL21-induced neurite outgrowth. Mechanistically, we found that CCL21 binds locally to its receptor CCR7 at the growth cone, activating the downstream MEK-ERK pathway, that in turn activates N-WASP, triggering actin filament ramification in the growth cone, resulting in increased axonal growth.


Asunto(s)
Ganglios Espinales , Nocicepción , Movimiento Celular , Quimiocina CCL21/metabolismo , Ganglios Espinales/metabolismo , Sistema de Señalización de MAP Quinasas , Receptores CCR7/metabolismo
11.
Mol Med ; 28(1): 97, 2022 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-35978278

RESUMEN

BACKGROUND: Neural tissue has limited regenerative ability. To cope with that, in recent years a diverse set of novel tools has been used to tailor neurostimulation therapies and promote functional regeneration after axonal injuries. METHOD: In this report, we explore cell-specific methods to modulate neuronal activity, including opto- and chemogenetics to assess the effect of specific neuronal stimulation in the promotion of axonal regeneration after injury. RESULTS: Opto- and chemogenetic stimulations of neuronal activity elicited increased in vitro neurite outgrowth in both sensory and cortical neurons, as well as in vivo regeneration in the sciatic nerve, but not after spinal cord injury. Mechanistically, inhibitory substrates such as chondroitin sulfate proteoglycans block the activity induced increase in axonal growth. CONCLUSIONS: We found that genetic modulations of neuronal activity on both dorsal root ganglia and corticospinal motor neurons increase their axonal growth capacity but only on permissive environments.


Asunto(s)
Neuronas , Traumatismos de la Médula Espinal , Axones/fisiología , Ganglios Espinales , Humanos , Regeneración Nerviosa , Neuronas/fisiología , Nervio Ciático/lesiones , Traumatismos de la Médula Espinal/terapia
12.
J Neuropathol Exp Neurol ; 81(9): 696-706, 2022 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-35848963

RESUMEN

The neocortex of P301S mice, used as a model of fronto-temporal lobar degeneration linked to tau mutation (FTLD-tau), and wild-type mice, both aged 9 months, were analyzed with conventional label-free phosphoproteomics and SWATH-MS (sequential window acquisition of all theoretical fragment ion spectra mass spectrometry) to assess the (phospho)proteomes. The total number of identified dysregulated phosphoproteins was 328 corresponding to 524 phosphorylation sites. The majority of dysregulated phosphoproteins, most of them hyperphosphorylated, were proteins of the membranes, synapses, membrane trafficking, membrane vesicles linked to endo- and exocytosis, cytoplasmic vesicles, and cytoskeleton. Another group was composed of kinases. In contrast, proteins linked to DNA, RNA metabolism, RNA splicing, and protein synthesis were hypophosphorylated. Other pathways modulating energy metabolism, cell signaling, Golgi apparatus, carbohydrates, and lipids are also targets of dysregulated protein phosphorylation in P301S mice. The present results, together with accompanying immunohistochemical and Western-blotting studies, show widespread abnormal phosphorylation of proteins, in addition to protein tau, in P301S mice. These observations point to dysregulated protein phosphorylation as a relevant contributory pathogenic component of tauopathies.


Asunto(s)
Degeneración Lobar Frontotemporal , Tauopatías , Animales , Modelos Animales de Enfermedad , Degeneración Lobar Frontotemporal/patología , Ratones , Ratones Transgénicos , Fosfoproteínas , Fosforilación , Tauopatías/patología , Proteínas tau/genética , Proteínas tau/metabolismo
13.
Front Cell Dev Biol ; 10: 886110, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35652101

RESUMEN

Emerging evidence points to coordinated action of chemical and mechanical cues during brain development. At early stages of neocortical development, angiogenic factors and chemokines such as CXCL12, ephrins, and semaphorins assume crucial roles in orchestrating neuronal migration and axon elongation of postmitotic neurons. Here we explore the intrinsic mechanical properties of the developing marginal zone of the pallium in the migratory pathways and brain distribution of the pioneer Cajal-Retzius cells. These neurons are generated in several proliferative regions in the developing brain (e.g., the cortical hem and the pallial subpallial boundary) and migrate tangentially in the preplate/marginal zone covering the upper portion of the developing cortex. These cells play crucial roles in correct neocortical layer formation by secreting several molecules such as Reelin. Our results indicate that the motogenic properties of Cajal-Retzius cells and their perinatal distribution in the marginal zone are modulated by both chemical and mechanical factors, by the specific mechanical properties of Cajal-Retzius cells, and by the differential stiffness of the migratory routes. Indeed, cells originating in the cortical hem display higher migratory capacities than those generated in the pallial subpallial boundary which may be involved in the differential distribution of these cells in the dorsal-lateral axis in the developing marginal zone.

14.
Int J Mol Sci ; 23(12)2022 Jun 08.
Artículo en Inglés | MEDLINE | ID: mdl-35742871

RESUMEN

Altered protein phosphorylation is a major pathologic modification in tauopathies and Alzheimer's disease (AD) linked to abnormal tau fibrillar deposits in neurofibrillary tangles (NFTs) and pre-tangles and ß-amyloid deposits in AD. hTau transgenic mice, which express 3R and less 4R human tau with no mutations in a murine knock-out background, show increased tau deposition in neurons but not NFTs and pre-tangles at the age of nine months. Label-free (phospho)proteomics and SWATH-MS identified 2065 proteins in hTau and wild-type (WT) mice. Only six proteins showed increased levels in hTau; no proteins were down-regulated. Increased tau phosphorylation in hTau was detected at Ser199, Ser202, Ser214, Ser396, Ser400, Thr403, Ser404, Ser413, Ser416, Ser422, Ser491, and Ser494, in addition to Thr181, Thr231, Ser396/Ser404, but not at Ser202/Thr205. In addition, 4578 phosphopeptides (corresponding to 1622 phosphoproteins) were identified in hTau and WT mice; 64 proteins were differentially phosphorylated in hTau. Sixty proteins were grouped into components of membranes, membrane signaling, synapses, vesicles, cytoskeleton, DNA/RNA/protein metabolism, ubiquitin/proteasome system, cholesterol and lipid metabolism, and cell signaling. These results showed that over-expression of human tau without pre-tangle and NFT formation preferentially triggers an imbalance in the phosphorylation profile of specific proteins involved in the cytoskeletal-membrane-signaling axis.


Asunto(s)
Enfermedad de Alzheimer , Proteínas tau , Enfermedad de Alzheimer/metabolismo , Animales , Encéfalo/metabolismo , Modelos Animales de Enfermedad , Humanos , Ratones , Ratones Transgénicos , Ovillos Neurofibrilares/metabolismo , Fosforilación , Proteínas tau/genética , Proteínas tau/metabolismo
15.
Int J Mol Sci ; 23(9)2022 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-35563179

RESUMEN

Alzheimer's disease (AD) and other tauopathies are common neurodegenerative diseases in older adults; in contrast, abnormal tau deposition in neurons and glial cells occurs only exceptionally in children. Sarkosyl-insoluble fractions from sporadic AD (sAD) containing paired helical filaments (PHFs) were inoculated unilaterally into the thalamus in newborn and three-month-old wild-type C57BL/6 mice, which were killed at different intervals from 24 h to six months after inoculation. Tau-positive cells were scanty and practically disappeared at three months in mice inoculated at the age of a newborn. In contrast, large numbers of tau-positive cells, including neurons and oligodendrocytes, were found in the thalamus of mice inoculated at three months and killed at the ages of six months and nine months. Mice inoculated at the age of newborn and re-inoculated at the age of three months showed similar numbers and distribution of positive cells in the thalamus at six months and nine months. This study shows that (a) differences in tau seeding between newborn and young adults may be related to the ratios between 3Rtau and 4Rtau, and the shift to 4Rtau predominance in adults, together with the immaturity of connections in newborn mice, and (b) intracerebral inoculation of sAD PHFs in newborn mice does not protect from tau seeding following intracerebral inoculation of sAD PHFs in young/adult mice.


Asunto(s)
Enfermedad de Alzheimer , Tauopatías , Animales , Encéfalo/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Ovillos Neurofibrilares/metabolismo , Proteínas tau/genética , Proteínas tau/metabolismo
17.
Mol Neurobiol ; 59(2): 1214-1229, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34962634

RESUMEN

Lafora disease (LD) is a fatal childhood-onset dementia characterized by the extensive accumulation of glycogen aggregates-the so-called Lafora Bodies (LBs)-in several organs. The accumulation of LBs in the brain underlies the neurological phenotype of the disease. LBs are composed of abnormal glycogen and various associated proteins, including p62, an autophagy adaptor that participates in the aggregation and clearance of misfolded proteins. To study the role of p62 in the formation of LBs and its participation in the pathology of LD, we generated a mouse model of the disease (malinKO) lacking p62. Deletion of p62 prevented LB accumulation in skeletal muscle and cardiac tissue. In the brain, the absence of p62 altered LB morphology and increased susceptibility to epilepsy. These results demonstrate that p62 participates in the formation of LBs and suggest that the sequestration of abnormal glycogen into LBs is a protective mechanism through which it reduces the deleterious consequences of its accumulation in the brain.


Asunto(s)
Enfermedad de Lafora , Animales , Modelos Animales de Enfermedad , Glucógeno/metabolismo , Cuerpos de Inclusión/metabolismo , Enfermedad de Lafora/genética , Ratones , Ratones Noqueados , Proteína Sequestosoma-1
18.
Brain Pathol ; 31(6): e12996, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34218486

RESUMEN

Tau hyperphosphorylation is the first step of neurofibrillary tangle (NFT) formation. In the present study, samples of the entorhinal cortex (EC) and frontal cortex area 8 (FC) of cases with NFT pathology classified as stages I-II, III-IV, and V-VI without comorbidities, and of middle-aged (MA) individuals with no NFT pathology, were analyzed by conventional label-free and SWATH-MS (sequential window acquisition of all theoretical fragment ion spectra mass spectrometry) to assess the (phospho)proteomes. The total number of identified dysregulated phosphoproteins was 214 in the EC, 65 of which were dysregulated at the first stages (I-II) of NFT pathology; 167 phosphoproteins were dysregulated in the FC, 81 of them at stages I-II of NFT pathology. A large percentage of dysregulated phosphoproteins were identified in the two regions and at different stages of NFT progression. The main group of dysregulated phosphoproteins was made up of components of the membranes, cytoskeleton, synapses, proteins linked to membrane transport and ion channels, and kinases. The present results show abnormal phosphorylation of proteins at the first stages of NFT pathology in the elderly (in individuals clinically considered representative of normal aging) and sporadic Alzheimer's disease (sAD). Dysregulated protein phosphorylation in the FC precedes the formation of NFTs and SPs. The most active period of dysregulated phosphorylation is at stages III-IV when a subpopulation of individuals might be clinically categorized as suffering from mild cognitive impairment which is a preceding determinant stage in the progression to dementia. Altered phosphorylation of selected proteins, carried out by activation of several kinases, may alter membrane and cytoskeletal functions, among them synaptic transmission and membrane/cytoskeleton signaling. Besides their implications in sAD, the present observations suggest a molecular substrate for "benign" cognitive deterioration in "normal" brain aging.


Asunto(s)
Envejecimiento/metabolismo , Enfermedad de Alzheimer/metabolismo , Encéfalo/metabolismo , Proteínas tau/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Envejecimiento/patología , Enfermedad de Alzheimer/patología , Encéfalo/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ovillos Neurofibrilares/metabolismo , Ovillos Neurofibrilares/patología , Fosforilación
19.
Int J Mol Sci ; 22(10)2021 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-34065232

RESUMEN

Tau protein is largely responsible for tauopathies, including Alzheimer's disease (AD), where it accumulates in the brain as insoluble aggregates. Tau mRNA is regulated by alternative splicing, and inclusion or exclusion of exon 10 gives rise to the 3R and 4R isoforms respectively, whose balance is physiologically regulated. In this sense, one of the several factors that regulate alternative splicing of tau is GSK3ß, whose activity is inhibited by the cellular prion protein (PrPC), which has different physiological functions in neuroprotection and neuronal differentiation. Moreover, a relationship between PrPC and tau expression levels has been reported during AD evolution. For this reason, in this study we aimed to analyze the role of PrPC and the implication of GSK3ß in the regulation of tau exon 10 alternative splicing. We used AD human samples and mouse models of PrPC ablation and tau overexpression. In addition, we used primary neuronal cultures to develop functional studies. Our results revealed a paralleled association between PrPC expression and tau 4R isoforms in all models analyzed. In this sense, reduction or ablation of PrPC levels induces an increase in tau 3R/4R balance. More relevantly, our data points to GSK3ß activity downstream from PrPC in this phenomenon. Our results indicate that PrPC plays a role in tau exon 10 inclusion through the inhibitory capacity of GSK3ß.


Asunto(s)
Regulación hacia Abajo/genética , Exones/genética , Glucógeno Sintasa Quinasa 3 beta/genética , Priones/genética , Proteínas tau/genética , Adulto , Anciano , Anciano de 80 o más Años , Empalme Alternativo/genética , Enfermedad de Alzheimer/genética , Animales , Encéfalo/patología , Modelos Animales de Enfermedad , Femenino , Humanos , Cuerpos de Inclusión/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Neuronas/patología , Isoformas de Proteínas/genética , ARN Mensajero/genética , Tauopatías/genética
20.
Front Bioeng Biotechnol ; 9: 627805, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33829009

RESUMEN

(Following spinal cord injury, olfactory ensheathing cell (OEC) transplantation is a promising therapeutic approach in promoting functional improvement. Some studies report that the migratory properties of OECs are compromised by inhibitory molecules and potentiated by chemical concentration differences. Here we compare the attachment, morphology, and directionality of an OEC-derived cell line, TEG3 cells, seeded on functionalized nanoscale meshes of Poly(l/dl-lactic acid; PLA) nanofibers. The size of the nanofibers has a strong effect on TEG3 cell adhesion and migration, with the PLA nanofibers having a 950 nm diameter being the ones that show the best results. TEG3 cells are capable of adopting a bipolar morphology on 950 nm fiber surfaces, as well as a highly dynamic behavior in migratory terms. Finally, we observe that functionalized nanofibers, with a chemical concentration increment of SDF-1α/CXCL12, strongly enhance the migratory characteristics of TEG3 cells over inhibitory substrates.

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