RESUMEN
Endoplasmic reticulum (ER) remodeling is vital for cellular organization. ER-phagy, a selective autophagy targeting ER, plays an important role in maintaining ER morphology and function. The FAM134 protein family, including FAM134A, FAM134B, and FAM134C, mediates ER-phagy. While FAM134B mutations are linked to hereditary sensory and autonomic neuropathy in humans, the physiological role of the other FAM134 proteins remains unknown. To address this, we investigate the roles of FAM134 proteins using single and combined knockouts (KOs) in mice. Single KOs in young mice show no major phenotypes; however, combined Fam134b and Fam134c deletion (Fam134b/cdKO), but not the combination including Fam134a deletion, leads to rapid neuromuscular and somatosensory degeneration, resulting in premature death. Fam134b/cdKO mice show rapid loss of motor and sensory axons in the peripheral nervous system. Long axons from Fam134b/cdKO mice exhibit expanded tubular ER with a transverse ladder-like appearance, whereas no obvious abnormalities are present in cortical ER. Our study unveils the critical roles of FAM134C and FAM134B in the formation of tubular ER network in axons of both motor and sensory neurons.
Asunto(s)
Axones , Retículo Endoplásmico , Proteínas de la Membrana , Animales , Humanos , Ratones , Axones/metabolismo , Retículo Endoplásmico/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones NoqueadosRESUMEN
Since the discovery of lysosomes more than 70 years ago, much has been learned about the functions of these organelles. Lysosomes were regarded as exclusively degradative organelles, but more recent research has shown that they play essential roles in several other cellular functions, such as nutrient sensing, intracellular signalling and metabolism. Methodological advances played a key part in generating our current knowledge about the biology of this multifaceted organelle. In this review, we cover current methods used to analyze lysosome morphology, positioning, motility and function. We highlight the principles behind these methods, the methodological strategies and their advantages and limitations. To extract accurate information and avoid misinterpretations, we discuss the best strategies to identify lysosomes and assess their characteristics and functions. With this review, we aim to stimulate an increase in the quantity and quality of research on lysosomes and further ground-breaking discoveries on an organelle that continues to surprise and excite cell biologists.
Asunto(s)
Lisosomas , Redes y Vías Metabólicas , Lisosomas/metabolismo , Transducción de SeñalRESUMEN
Mucopolysaccharidosis type IIIA (MPS-IIIA) is an autosomal recessive disorder caused by mutations in SGSH involved in the degradation of heparan sulfate. MPS-IIIA presents severe neurological symptoms such as progressive developmental delay and cognitive decline, for which there is currently no treatment. Brain targeting represents the main challenge for therapeutics to treat MPS-IIIA, and the development of small-molecule-based treatments able to reach the CNS could be a relevant advance for therapy. Using cell-based high content imaging to survey clinically approved drugs in MPS-IIIA cells, we identified fluoxetine, a selective serotonin reuptake inhibitor. Fluoxetine increases lysosomal and autophagic functions via TFEB activation through a RagC-dependent mechanism. Mechanistically, fluoxetine increases lysosomal exocytosis in mouse embryonic fibroblasts from MPS-IIIA mice, suggesting that this process may be responsible for heparan sulfate clearance. In vivo, fluoxetine ameliorates somatic and brain pathology in a mouse model of MPS-IIIA by decreasing the accumulation of glycosaminoglycans and aggregated autophagic substrates, reducing inflammation, and slowing down cognitive deterioration. We repurposed fluoxetine for potential therapeutics to treat human MPS-IIIA disease.
Asunto(s)
Mucopolisacaridosis III , Animales , Modelos Animales de Enfermedad , Fibroblastos/metabolismo , Fluoxetina/farmacología , Fluoxetina/uso terapéutico , Heparitina Sulfato/metabolismo , Hidrolasas/genética , Ratones , Mucopolisacaridosis III/tratamiento farmacológico , Mucopolisacaridosis III/genéticaRESUMEN
Misfolding and aggregation of α-synuclein are specific features of Parkinson's disease and other neurodegenerative diseases defined as synucleinopathies. Parkinson's disease progression has been correlated with the formation and extracellular release of α-synuclein aggregates, as well as with their spread from neuron to neuron. Therapeutic interventions in the initial stages of Parkinson's disease require a clear understanding of the mechanisms by which α-synuclein disrupts the physiological synaptic and plastic activity of the basal ganglia. For this reason, we identified two early time points to clarify how the intrastriatal injection of α-synuclein-preformed fibrils in rodents via retrograde transmission induces time-dependent electrophysiological and behavioural alterations. We found that intrastriatal α-synuclein-preformed fibrils perturb the firing rate of dopaminergic neurons in the substantia nigra pars compacta, while the discharge of putative GABAergic cells of the substantia nigra pars reticulata is unchanged. The α-synuclein-induced dysregulation of nigrostriatal function also impairs, in a time-dependent manner, the two main forms of striatal synaptic plasticity, long-term potentiation and long-term depression. We also observed an increased glutamatergic transmission measured as an augmented frequency of spontaneous excitatory synaptic currents. These changes in neuronal function in the substantia nigra pars compacta and striatum were observed before overt neuronal death occurred. In an additional set of experiments, we were able to rescue α-synuclein-induced alterations of motor function, striatal synaptic plasticity and increased spontaneous excitatory synaptic currents by subchronic treatment with l-DOPA, a precursor of dopamine widely used in the therapy of Parkinson's disease, clearly demonstrating that a dysfunctional dopamine system plays a critical role in the early phases of the disease.
Asunto(s)
Plasticidad Neuronal/fisiología , Enfermedad de Parkinson/fisiopatología , Sustancia Negra/fisiopatología , Transmisión Sináptica/fisiología , alfa-Sinucleína/toxicidad , Animales , Dopamina/metabolismo , Neuronas Dopaminérgicas/metabolismo , Neuronas Dopaminérgicas/patología , Masculino , Enfermedad de Parkinson/metabolismo , Ratas , Ratas Wistar , Sustancia Negra/metabolismo , alfa-Sinucleína/metabolismoRESUMEN
Lysosomal storage diseases (LSDs) are inherited disorders caused by lysosomal deficiencies and characterized by dysfunction of the autophagy-lysosomal pathway (ALP) often associated with neurodegeneration. No cure is currently available to treat neuropathology in LSDs. By studying a mouse model of mucopolysaccharidosis (MPS) type IIIA, one of the most common and severe forms of LSDs, we found that multiple amyloid proteins including α-synuclein, prion protein (PrP), Tau, and amyloid ß progressively aggregate in the brain. The amyloid deposits mostly build up in neuronal cell bodies concomitantly with neurodegeneration. Treating MPS-IIIA mice with CLR01, a "molecular tweezer" that acts as a broad-spectrum inhibitor of amyloid protein self-assembly reduced lysosomal enlargement and re-activates autophagy flux. Restoration of the ALP was associated with reduced neuroinflammation and amelioration of memory deficits. Together, these data provide evidence that brain deposition of amyloid proteins plays a gain of neurotoxic function in a severe LSD by affecting the ALP and identify CLR01 as new potent drug candidate for MPS-IIIA and likely for other LSDs.
Asunto(s)
Autofagia/efectos de los fármacos , Hidrocarburos Aromáticos con Puentes/administración & dosificación , Mucopolisacaridosis III/tratamiento farmacológico , Enfermedades Neurodegenerativas/tratamiento farmacológico , Organofosfatos/administración & dosificación , Amiloide/antagonistas & inhibidores , Amiloide/metabolismo , Animales , Encéfalo/metabolismo , Hidrocarburos Aromáticos con Puentes/farmacología , Cuerpo Celular/metabolismo , Modelos Animales de Enfermedad , Masculino , Ratones , Mucopolisacaridosis III/complicaciones , Mucopolisacaridosis III/metabolismo , Enfermedades Neurodegenerativas/etiología , Organofosfatos/farmacología , Resultado del TratamientoRESUMEN
Parkinson's disease is a progressive neurodegenerative disorder characterized by altered striatal dopaminergic signalling that leads to motor and cognitive deficits. Parkinson's disease is also characterized by abnormal presence of soluble toxic forms of α-synuclein that, when clustered into Lewy bodies, represents one of the pathological hallmarks of the disease. However, α-synuclein oligomers might also directly affect synaptic transmission and plasticity in Parkinson's disease models. Accordingly, by combining electrophysiological, optogenetic, immunofluorescence, molecular and behavioural analyses, here we report that α-synuclein reduces N-methyl-d-aspartate (NMDA) receptor-mediated synaptic currents and impairs corticostriatal long-term potentiation of striatal spiny projection neurons, of both direct (D1-positive) and indirect (putative D2-positive) pathways. Intrastriatal injections of α-synuclein produce deficits in visuospatial learning associated with reduced function of GluN2A NMDA receptor subunit indicating that this protein selectively targets this subunit both in vitro and ex vivo. Interestingly, this effect is observed in spiny projection neurons activated by optical stimulation of either cortical or thalamic glutamatergic afferents. We also found that treatment of striatal slices with antibodies targeting α-synuclein prevents the α-synuclein-induced loss of long-term potentiation and the reduced synaptic localization of GluN2A NMDA receptor subunit suggesting that this strategy might counteract synaptic dysfunction occurring in Parkinson's disease.
Asunto(s)
Cuerpo Estriado/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Memoria Espacial/fisiología , Sinapsis/fisiología , Percepción Visual/fisiología , alfa-Sinucleína/toxicidad , Animales , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/patología , Humanos , Potenciación a Largo Plazo/efectos de los fármacos , Potenciación a Largo Plazo/fisiología , Masculino , Ratones , Ratones Transgénicos , Técnicas de Cultivo de Órganos , Subunidades de Proteína/antagonistas & inhibidores , Subunidades de Proteína/metabolismo , Ratas , Ratas Wistar , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Memoria Espacial/efectos de los fármacos , Sinapsis/efectos de los fármacos , Percepción Visual/efectos de los fármacos , alfa-Sinucleína/administración & dosificaciónRESUMEN
Nigro-striatal dopamine transmission is central to a wide range of neuronal functions, including skill learning, which is disrupted in several pathologies such as Parkinson's disease. The synaptic plasticity mechanisms, by which initial motor learning is stored for long time periods in striatal neurons, to then be gradually optimized upon subsequent training, remain unexplored. Addressing this issue is crucial to identify the synaptic and molecular mechanisms involved in striatal-dependent learning impairment in Parkinson's disease. In this study, we took advantage of interindividual differences between outbred rodents in reaching plateau performance in the rotarod incremental motor learning protocol, to study striatal synaptic plasticity ex vivo. We then assessed how this process is modulated by dopamine receptors and the dopamine active transporter, and whether it is impaired by overexpression of human α-synuclein in the mesencephalon; the latter is a progressive animal model of Parkinson's disease. We found that the initial acquisition of motor learning induced a dopamine active transporter and D1 receptors mediated long-term potentiation, under a protocol of long-term depression in striatal medium spiny neurons. This effect disappeared in animals reaching performance plateau. Overexpression of human α-synuclein reduced striatal dopamine active transporter levels, impaired motor learning, and prevented the learning-induced long-term potentiation, before the appearance of dopamine neuronal loss. Our findings provide evidence of a reorganization of cellular plasticity within the dorsolateral striatum that is mediated by dopamine receptors and dopamine active transporter during the acquisition of a skill. This newly identified mechanism of cellular memory is a form of metaplasticity that is disrupted in the early stage of synucleinopathies, such as Parkinson's disease, and that might be relevant for other striatal pathologies, such as drug abuse.
Asunto(s)
Cuerpo Estriado/citología , Aprendizaje/fisiología , Actividad Motora/fisiología , Plasticidad Neuronal/fisiología , Neuronas/fisiología , Animales , Benzazepinas/farmacología , Antagonistas de Dopamina/farmacología , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Inhibidores de Captación de Dopamina/farmacología , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Aprendizaje/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Potenciación a Largo Plazo/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Actividad Motora/efectos de los fármacos , Destreza Motora/efectos de los fármacos , Piperazinas/farmacología , Tiempo de Reacción/fisiología , Sinapsinas/genética , Sinapsinas/metabolismo , Sinaptofisina/metabolismo , Tirosina 3-Monooxigenasa/metabolismo , alfa-Sinucleína/metabolismo , alfa-Sinucleína/farmacologíaRESUMEN
Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive degeneration of dopaminergic neurons located in the midbrain. The gold-standard therapy for PD is the restoration of dopamine (DA) levels through the chronic administration of the DA precursor levodopa (L-DOPA). Although levodopa therapy is the main therapeutic approach for PD, its use is limited by the development of very disabling dyskinetic movements, mainly due to the fluctuation of DA cerebral content. Experimental animal models of PD identified in DA D1/ERK-signaling pathway aberrant activation, occurring in striatal projection neurons, coupled with structural spines abnormalities, the molecular and neuronal basis of L-DOPA-induced dyskinesia (LIDs) occurrence. Different electrophysiological approaches allowed the identification of the alteration of homeostatic structural and synaptic changes, the neuronal bases of LIDs either in vivo in parkinsonian patients or in vitro in experimental animals. Here, we report the most recent studies showing electrophysiological and morphological evidence of aberrant synaptic plasticity in parkinsonian patients during LIDs in different basal ganglia nuclei and also in cortical transmission, accounting for the complexity of the synaptic changes during dyskinesias. All together, these studies suggest that LIDs are associated with a loss of homeostatic synaptic mechanisms.
Asunto(s)
Cuerpo Estriado/fisiopatología , Discinesia Inducida por Medicamentos/fisiopatología , Plasticidad Neuronal/fisiología , Animales , Antiparkinsonianos/efectos adversos , Humanos , Levodopa/efectos adversosRESUMEN
The hippocampus (HP), a medial cortical structure, is subdivided into a distinct dorsal (septal) and ventral (temporal) portion, which is separated by an intermediate region lying on a longitudinal curvature. While the dorsal portion is more dedicated to spatial navigation and memory, the most ventral part processes emotional information. Genetic factors expressed in gradient during development seem to control the size and correct positioning of the HP along its longitudinal axis; however, their roles in regulating differential growth and in supporting its anatomical and functional dissociation remain unexplored. Here, we challenge the in vivo function of the nuclear receptor COUP-TFI (chicken ovalbumin upstream promoter transcription factor 1) in controlling the hippocampal, anatomical, and functional properties along its longitudinal axis. Loss of cortical COUP-TFI function results in a dysmorphic HP with altered shape, volume, and connectivity, particularly in its dorsal and intermediate regions. Notably, topographic inputs from the entorhinal cortex are strongly impaired in the dorsal portion of COUP-TFI mutants. These severe morphological changes are associated with selective spatial learning and memory impairment. These findings identify a novel transcriptional regulator required in the functional organization along the hippocampal septo-temporal axis supporting a genetic basis of the hippocampal volumetric growth with its final shape, circuit, and type of memory function.
Asunto(s)
Factor de Transcripción COUP I/genética , Regulación de la Expresión Génica/fisiología , Hipocampo/metabolismo , Animales , Ratones Transgénicos , Regiones Promotoras Genéticas/genética , Transducción de Señal/fisiologíaRESUMEN
Transcription factors with gradients of expression in neocortical progenitors give rise to distinct motor and sensory cortical areas by controlling the area-specific differentiation of distinct neuronal subtypes. However, the molecular mechanisms underlying this area-restricted control are still unclear. Here, we show that COUP-TFI controls the timing of birth and specification of corticospinal motor neurons (CSMN) in somatosensory cortex via repression of a CSMN differentiation program. Loss of COUP-TFI function causes an area-specific premature generation of neurons with cardinal features of CSMN, which project to subcerebral structures, including the spinal cord. Concurrently, genuine CSMN differentiate imprecisely and do not project beyond the pons, together resulting in impaired skilled motor function in adult mice with cortical COUP-TFI loss-of-function. Our findings indicate that COUP-TFI exerts critical areal and temporal control over the precise differentiation of CSMN during corticogenesis, thereby enabling the area-specific functional features of motor and sensory areas to arise.
Asunto(s)
Factor de Transcripción COUP I/metabolismo , Regulación del Desarrollo de la Expresión Génica , Neuronas Motoras/citología , Neurogénesis/genética , Tractos Piramidales/citología , Lóbulo Temporal/crecimiento & desarrollo , Animales , Factor de Transcripción COUP I/genética , Ratones , Ratones Noqueados , Neuronas Motoras/metabolismo , Tractos Piramidales/metabolismo , Lóbulo Temporal/metabolismo , Tálamo/crecimiento & desarrollo , Tálamo/metabolismoRESUMEN
The dorsal hippocampus is crucial for mammalian spatial memory, but its exact role in item memory is still hotly debated. Recent evidence in humans suggested that the hippocampus might be selectively involved in item short-term memory to deal with an increasing memory load. In this study, we sought to test this hypothesis. To this aim we developed a novel behavioral procedure to study object memory load in mice by progressively increasing the stimulus set size in the spontaneous object recognition task. Using this procedure, we demonstrated that naive mice have a memory span, which is the number of elements they can remember for a short-time interval, of about six objects. Then, we showed that excitotoxic selective lesions of the dorsal hippocampus did not impair novel object discrimination in the condition of low memory load. In contrast, the same lesion impaired novel object discrimination in the high memory load condition, and reduced the object memory span to four objects. These results have important heuristic and clinical implications because they open new perspective toward the understanding of the role of the hippocampus in item memory and in memory span deficits occurring in human pathologies, such as Alzheimer's disease and schizophrenia.
Asunto(s)
Hipocampo/fisiología , Reconocimiento en Psicología/fisiología , Animales , Masculino , RatonesRESUMEN
N-oleoylglycine (OlGly), a lipid derived from the basic component of olive oil, oleic acid, and N-oleoylalanine (OlAla) are endocannabinoid-like mediators. We report that OlGly and OlAla, by activating the peroxisome proliferator-activated receptor alpha (PPARα), reduce the rewarding properties of a highly palatable food, dopamine neuron firing in the ventral tegmental area, and the obesogenic effect of a high-fat diet rich in lard (HFD-L). An isocaloric olive oil HFD (HFD-O) reduced body weight gain compared to the HFD-L, in a manner reversed by PPARα antagonism, and enhanced brain and intestinal OlGly levels and gut microbial diversity. OlGly or OlAla treatment of HFD-L mice resulted in gut microbiota taxonomic changes partly similar to those induced by HFD-O. We suggest that OlGly and OlAla control body weight by counteracting highly palatable food overconsumption, and possibly rebalancing the gut microbiota, and provide a potential new mechanism of action for the obeso-preventive effects of olive oil-rich diets.
Asunto(s)
Endocannabinoides , PPAR alfa , Animales , Ratones , Aceite de Oliva/farmacología , Obesidad/etiología , Obesidad/prevención & control , Peso CorporalRESUMEN
Cognitive deficits, including working memory, and visuospatial deficits are common and debilitating in Parkinson's disease. α-synucleinopathy in the hippocampus and cortex is considered as the major risk factor. However, little is known about the progression and specific synaptic mechanisms underlying the memory deficits induced by α-synucleinopathy. Here, we tested the hypothesis that pathologic α-Synuclein (α-Syn), initiated in different brain regions, leads to distinct onset and progression of the pathology. We report that overexpression of human α-Syn in the murine mesencephalon leads to late onset memory impairment and sensorimotor deficits accompanied by reduced dopamine D1 expression in the hippocampus. In contrast, human α-Syn overexpression in the hippocampus leads to early memory impairment, altered synaptic transmission and plasticity, and decreased expression of GluA1 AMPA-type glutamate receptors. These findings identify the synaptic mechanisms leading to memory impairment induced by hippocampal α-synucleinopathy and provide functional evidence of the major neuronal networks involved in disease progression.
RESUMEN
Intensive physical activity improves motor functions in patients with Parkinson's disease (PD) at early stages. However, the mechanisms underlying the beneficial effects of exercise on PD-associated neuronal alterations have not been fully clarified yet. Here, we tested the hypothesis that an intensive treadmill training program rescues alterations in striatal plasticity and early motor and cognitive deficits in rats receiving an intrastriatal injection of alpha-synuclein (α-syn) preformed fibrils. Improved motor control and visuospatial learning in active animals were associated with a recovery of dendritic spine density alterations and a lasting rescue of a physiological corticostriatal long-term potentiation (LTP). Pharmacological analyses of LTP show that modulations of N-methyl-d-aspartate receptors bearing GluN2B subunits and tropomyosin receptor kinase B, the main brain-derived neurotrophic factor receptor, are involved in these beneficial effects. We demonstrate that intensive exercise training has effects on the early plastic alterations induced by α-syn aggregates and reduces the spread of toxic α-syn species to other vulnerable brain areas.
Asunto(s)
Enfermedad de Parkinson , Ratas , Animales , Enfermedad de Parkinson/terapia , Plasticidad Neuronal/fisiología , Cuerpo Estriado , Potenciación a Largo Plazo/fisiología , CogniciónRESUMEN
Here, we describe a conserved motor neuron-specific long non-coding RNA, Lhx1os, whose knockout in mice produces motor impairment and postnatal reduction of mature motor neurons (MNs). The ER stress-response pathway result specifically altered with the downregulation of factors involved in the unfolded protein response (UPR). Lhx1os was found to bind the ER-associated PDIA3 disulfide isomerase and to affect the expression of the same set of genes controlled by this protein, indicating that the two factors act in conjunction to modulate the UPR. Altogether, the observed phenotype and function of Lhx1os indicate its important role in the control of MN homeostasis and function.
RESUMEN
Microglia reactivity entails a large-scale remodeling of cellular geometry, but the behavior of the microtubule cytoskeleton during these changes remains unexplored. Here we show that activated microglia provide an example of microtubule reorganization from a non-centrosomal array of parallel and stable microtubules to a radial array of more dynamic microtubules. While in the homeostatic state, microglia nucleate microtubules at Golgi outposts, and activating signaling induces recruitment of nucleating material nearby the centrosome, a process inhibited by microtubule stabilization. Our results demonstrate that a hallmark of microglia reactivity is a striking remodeling of the microtubule cytoskeleton and suggest that while pericentrosomal microtubule nucleation may serve as a distinct marker of microglia activation, inhibition of microtubule dynamics may provide a different strategy to reduce microglia reactivity in inflammatory disease.
Asunto(s)
Microglía , Microtúbulos , Centrosoma , Citoesqueleto , Aparato de Golgi , Tubulina (Proteína)RESUMEN
In rodents, cortical interneurons originate from the medial ganglionic eminence (MGE) and caudal ganglionic eminence (CGE) according to precise temporal schedules. The mechanisms controlling the specification of CGE-derived interneurons and their role in cortical circuitry are still unknown. Here, we show that COUP-TFI expression becomes restricted to the dorsal MGE and CGE at embryonic day 13.5 in the basal telencephalon. Conditional loss of function of COUP-TFI in subventricular precursors and postmitotic cells leads to a decrease of late-born, CGE-derived, VIP (vasoactive intestinal peptide)- and CR (calretinin)-expressing bipolar cortical neurons, compensated by the concurrent increase of early-born MGE-derived, PV (parvalbumin)-expressing interneurons. Strikingly, COUP-TFI mutants are more resistant to pharmacologically induced seizures, a phenotype that is dependent on GABAergic signaling. Together, our data indicate that COUP-TFI controls the delicate balance between MGE- and CGE-derived cortical interneurons by regulating intermediate progenitor divisions and ultimately affecting the activity of the cortical inhibitory circuitry.
Asunto(s)
Factor de Transcripción COUP I/genética , Factor de Transcripción COUP I/fisiología , Corteza Cerebral/fisiología , Epilepsia/genética , Epilepsia/fisiopatología , Interneuronas/fisiología , Eminencia Media/fisiología , Animales , Antimetabolitos , Bromodesoxiuridina , Proliferación Celular , Corteza Cerebral/citología , Convulsivantes/farmacología , Resistencia a Medicamentos/genética , Electroencefalografía , Fenómenos Electrofisiológicos , Epilepsia/inducido químicamente , Inmunohistoquímica , Hibridación in Situ , Eminencia Media/citología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Red Nerviosa/citología , Red Nerviosa/fisiología , Receptores de GABA-A/genética , Receptores de GABA-A/fisiología , Receptores de GABA-B/genética , Receptores de GABA-B/fisiología , Telencéfalo/citología , Telencéfalo/fisiología , Ácido gamma-Aminobutírico/fisiologíaRESUMEN
Spinal muscular atrophy (SMA) is an inherited neurodegenerative disorder and the first genetic cause of death in childhood. SMA is caused by low levels of survival motor neuron (SMN) protein that induce selective loss of α-motor neurons (MNs) in the spinal cord, resulting in progressive muscle atrophy and consequent respiratory failure. To date, no effective treatment is available to counteract the course of the disease. Among the different therapeutic strategies with potential clinical applications, the evaluation of trophic and/or protective agents able to antagonize MNs degeneration represents an attractive opportunity to develop valid therapies. Here we investigated the effects of IPLEX (recombinant human insulinlike growth factor 1 [rhIGF-1] complexed with recombinant human IGF-1 binding protein 3 [rhIGFBP-3]) on a severe mouse model of SMA. Interestingly, molecular and biochemical analyses of IGF-1 carried out in SMA mice before drug administration revealed marked reductions of IGF-1 circulating levels and hepatic mRNA expression. In this study, we found that perinatal administration of IPLEX, even if does not influence survival and body weight of mice, results in reduced degeneration of MNs, increased muscle fiber size and in amelioration of motor functions in SMA mice. Additionally, we show that phenotypic changes observed are not SMN-dependent, since no significant SMN modification was addressed in treated mice. Collectively, our data indicate IPLEX as a good therapeutic candidate to hinder the progression of the neurodegenerative process in SMA.
Asunto(s)
Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/administración & dosificación , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/uso terapéutico , Factor I del Crecimiento Similar a la Insulina/administración & dosificación , Factor I del Crecimiento Similar a la Insulina/uso terapéutico , Actividad Motora/efectos de los fármacos , Neuronas Motoras/patología , Atrofia Muscular Espinal/tratamiento farmacológico , Atrofia Muscular Espinal/fisiopatología , Animales , Supervivencia Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Humanos , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/farmacología , Factor I del Crecimiento Similar a la Insulina/metabolismo , Factor I del Crecimiento Similar a la Insulina/farmacología , Ratones , Neuronas Motoras/efectos de los fármacos , Músculos/efectos de los fármacos , Músculos/patología , Músculos/fisiopatología , Atrofia Muscular Espinal/sangre , Atrofia Muscular Espinal/patología , Degeneración Nerviosa/tratamiento farmacológico , Degeneración Nerviosa/patología , Degeneración Nerviosa/fisiopatología , Fenotipo , Proteína 2 para la Supervivencia de la Neurona Motora/genética , Transcripción Genética/efectos de los fármacosRESUMEN
Multiple sulfatase deficiency (MSD), a severe autosomal recessive disease is caused by mutations in the sulfatase modifying factor 1 gene (Sumf1). We have previously shown that in the Sumf1 knockout mouse model (Sumf1(-/-)) sulfatase activities are completely absent and, similarly to MSD patients, this mouse model displays growth retardation and early mortality. The severity of the phenotype makes MSD unsuitable to be treated by enzyme replacement or bone marrow transplantation, hence the importance of testing the efficacy of novel treatment strategies. Here we show that recombinant adeno-associated virus serotype 9 (rAAV9) vector injected into the cerebral ventricles of neonatal mice resulted in efficient and widespread transduction of the brain parenchyma. In addition, we compared a combined, intracerebral ventricles and systemic, administration of an rAAV9 vector encoding SUMF1 gene to the single administrations-either directly in brain, or systemic alone -in MSD mice. The combined treatment resulted in the global activation of sulfatases, near-complete clearance of glycosaminoglycans (GAGs) and decrease of inflammation in both the central nervous system (CNS) and visceral organs. Furthermore, behavioral abilities were improved by the combined treatment. These results underscore that the "combined" mode of rAAV9 vector administration is an efficient option for the treatment of severe whole-body disorders.