RESUMEN
Neurodevelopmental disorders are characterized by alterations in the development of the cerebral cortex, including aberrant changes in the number and function of neural cells. Although neurogenesis is one of the most studied cellular processes in these pathologies, little evidence is known about glial development. Genetic association studies have identified several genes associated with neurodevelopmental disorders. Indeed, variations in the PTPRD gene have been associated with numerous brain disorders, including autism spectrum disorder, restless leg syndrome, and schizophrenia. We previously demonstrated that constitutive loss of PTPRD expression induces significant alterations in cortical neurogenesis, promoting an increase in intermediate progenitors and neurons in mice. However, its role in gliogenesis has not been evaluated. To assess this, we developed a conditional knockout mouse model lacking PTPRD expression in telencephalon cells. Here, we found that the lack of PTPRD in the mouse cortex reduces glial precursors, astrocytes, and oligodendrocytes. According to our results, this decrease in gliogenesis resulted from a reduced number of radial glia cells at gliogenesis onset and a lower gliogenic potential in cortical neural precursors due to less activation of the JAK/STAT pathway and reduced expression of gliogenic genes. Our study shows PTPRD as a regulator of the glial/neuronal balance during cortical neurodevelopment and highlights the importance of studying glial development to understand the etiology of neurodevelopmental diseases.
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Infections during pregnancy can seriously damage fetal neurodevelopment by aberrantly activating the maternal immune system, directly impacting fetal neural cells. Increasing evidence suggests that these adverse impacts involve alterations in neural stem cell biology with long-term consequences for offspring, including neurodevelopmental disorders such as autism spectrum disorder, schizophrenia, and cognitive impairment. Here we review how maternal infection with viruses such as Influenza A, Cytomegalovirus, and Zika during pregnancy can affect the brain development of offspring by promoting the release of maternal pro-inflammatory cytokines, triggering neuroinflammation of the fetal brain, and/or directly infecting fetal neural cells. In addition, we review insights into how these infections impact human brain development from studies with animal models and brain organoids. Finally, we discuss how maternal infection with SARS-CoV-2 may have consequences for neurodevelopment of the offspring.
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Trastorno del Espectro Autista , COVID-19 , Virosis , Infección por el Virus Zika , Virus Zika , Animales , Trastorno del Espectro Autista/etiología , Encéfalo , Citocinas , Femenino , Embarazo , SARS-CoV-2 , Virosis/complicacionesRESUMEN
Parkinson's disease is the second most common neurodegenerative disorder. Although it is clear that dopaminergic neurons degenerate, the underlying molecular mechanisms are still unknown, and thus, successful treatment is still elusive. One pro-apoptotic pathway associated with several neurodegenerative diseases is the tyrosine kinase c-Abl and its target p73. Here, we evaluated the contribution of c-Abl and p73 in the degeneration of dopaminergic neurons induced by the neurotoxin 6-hydroxydopamine as a model for Parkinson's disease. First, we found that in SH-SY5Y cells treated with 6-hydroxydopamine, c-Abl and p73 phosphorylation levels were up-regulated. Also, we found that the pro-apoptotic p73 isoform TAp73 was up-regulated. Then, to evaluate whether c-Abl tyrosine kinase activity is necessary for 6-hydroxydopamine-induced apoptosis, we co-treated SH-SY5Y cells with 6-hydroxydopamine and Imatinib, a c-Abl specific inhibitor, observing that Imatinib prevented p73 phosphorylation, TAp73 up-regulation, and protected SH-SY5Y cells treated with 6-hydroxydopamine from apoptosis. Interestingly, this observation was confirmed in the c-Abl conditional null mice, where 6-hydroxydopamine stereotaxic injections induced a lesser reduction of dopaminergic neurons than in the wild-type mice significantly. Finally, we found that the intraperitoneal administration of Imatinib prevented the death of dopaminergic neurons induced by injecting 6-hydroxydopamine stereotaxically in the mice striatum. Thus, our findings support the idea that the c-Abl/p73 pathway is involved in 6-hydroxydopamine degeneration and suggest that inhibition of its kinase activity might be used as a therapeutical drug in Parkinson's disease.
RESUMEN
BACKGROUND: Neuroinflammation constitutes a pathogenic process leading to neurodegeneration in several disorders, including Alzheimer's disease, Parkinson's disease (PD) and sepsis. Despite microglial cells being the central players in neuroinflammation, astrocytes play a key regulatory role in this process. Our previous results indicated that pharmacologic-antagonism or genetic deficiency of dopamine receptor D3 (DRD3) attenuated neuroinflammation and neurodegeneration in two mouse models of PD. Here, we studied how DRD3-signalling affects the dynamic of activation of microglia and astrocyte in the context of systemic inflammation. METHODS: Neuroinflammation was induced by intraperitoneal administration of LPS. The effect of genetic DRD3-deficiency or pharmacologic DRD3-antagonism in the functional phenotype of astrocytes and microglia was determined by immunohistochemistry and flow cytometry at different time-points. RESULTS: Our results show that DRD3 was expressed in astrocytes, but not in microglial cells. DRD3 deficiency resulted in unresponsiveness of astrocytes and in attenuated microglial activation upon systemic inflammation. Furthermore, similar alterations in the functional phenotypes of glial cells were observed by DRD3 antagonism and genetic deficiency of DRD3 upon LPS challenge. Mechanistic analyses show that DRD3 deficiency resulted in exacerbated expression of the anti-inflammatory protein Fizz1 in glial cells both in vitro and in vivo. CONCLUSIONS: These results suggest that DRD3 signalling regulates the dynamic of the acquisition of pro-inflammatory and anti-inflammatory features by astrocytes and microglia, finally favouring microglial activation and promoting neuroinflammation.
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Astrocitos/metabolismo , Mediadores de Inflamación/metabolismo , Microglía/metabolismo , Receptores de Dopamina D3/metabolismo , Transducción de Señal/fisiología , Animales , Astrocitos/efectos de los fármacos , Células Cultivadas , Inflamación/inducido químicamente , Inflamación/genética , Inflamación/metabolismo , Lipopolisacáridos/toxicidad , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microglía/efectos de los fármacos , Trastornos Parkinsonianos/inducido químicamente , Trastornos Parkinsonianos/genética , Trastornos Parkinsonianos/metabolismo , Receptores de Dopamina D3/antagonistas & inhibidores , Receptores de Dopamina D3/genética , Transducción de Señal/efectos de los fármacosRESUMEN
Neuroinflammation constitutes a fundamental process involved in Parkinson's disease (PD). Microglial cells play a central role in the outcome of neuroinflammation and consequent neurodegeneration of dopaminergic neurons in the substantia nigra. Current evidence indicates that CD4+ T-cells infiltrate the brain in PD, where they play a critical role determining the functional phenotype of microglia, thus regulating the progression of the disease. We previously demonstrated that mice bearing dopamine receptor D3 (DRD3)-deficient CD4+ T-cells are completely refractory to neuroinflammation and consequent neurodegeneration induced by the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In this study we aimed to determine whether DRD3-signalling is altered in peripheral blood CD4+ T-cells obtained from PD patients in comparison to healthy controls (HC). Furthermore, we evaluated the therapeutic potential of targeting DRD3 confined to CD4+ T-cells by inducing the pharmacologic antagonism or the transcriptional inhibition of DRD3-signalling in a mouse model of PD induced by the chronic administration of MPTP and probenecid (MPTPp). In vitro analyses performed in human cells showed that the frequency of peripheral blood Th1 and Th17 cells, two phenotypes favoured by DRD3-signalling, were significantly increased in PD patients. Moreover, naïve CD4+ T-cells obtained from PD patients displayed a significant higher Th1-biased differentiation in comparison with those naïve CD4+ T-cells obtained from HC. Nevertheless, DRD3 expression was selectively reduced in CD4+ T-cells obtained from PD patients. The results obtained from in vivo experiments performed in mice show that the transference of CD4+ T-cells treated ex vivo with the DRD3-selective antagonist PG01037 into MPTPp-mice resulted in a significant reduction of motor impairment, although without significant effect in neurodegeneration. Conversely, the transference of CD4+ T-cells transduced ex vivo with retroviral particles codifying for an shRNA for DRD3 into MPTPp-mice had no effects neither in motor impairment nor in neurodegeneration. Notably, the systemic antagonism of DRD3 significantly reduced both motor impairment and neurodegeneration in MPTPp mice. Our findings show a selective alteration of DRD3-signalling in CD4+ T-cells from PD patients and indicate that the selective DRD3-antagonism in this subset of lymphocytes exerts a therapeutic effect in parkinsonian animals dampening motor impairment.
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Benzamidas/uso terapéutico , Linfocitos T CD4-Positivos/fisiología , Trastornos Motores/tratamiento farmacológico , Enfermedad de Parkinson/inmunología , Trastornos Parkinsonianos/tratamiento farmacológico , Piridinas/uso terapéutico , Receptores de Dopamina D3/fisiología , Anciano , Animales , Modelos Animales de Enfermedad , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Receptores de Dopamina D3/antagonistas & inhibidores , Transducción de Señal/fisiología , Células TH1/citologíaRESUMEN
Parkinson's disease (PD) is a neurodegenerative disorder affecting mainly the dopaminergic neurons of the nigrostriatal pathway, a neuronal circuit involved in the control of movements, thereby the main manifestations correspond to motor impairments. The major molecular hallmark of this disease corresponds to the presence of pathological protein inclusions called Lewy bodies in the midbrain of patients, which have been extensively associated with neurotoxic effects. Importantly, different research groups have demonstrated that CD4+ T-cells infiltrate into the substantia nigra of PD patients and animal models. Moreover, several studies have consistently demonstrated that T-cell deficiency results in a strong attenuation of dopaminergic neurodegeneration in animal models of PD, thus indicating a key role of adaptive immunity in the neurodegenerative process. Recent evidence has shown that CD4+ T-cell response involved in PD patients is directed to oxidised forms of α-synuclein, one of the main constituents of Lewy bodies. On the other hand, most PD patients present a number of non-motor manifestations. Among non-motor manifestations, gastrointestinal dysfunctions result especially important as potential early biomarkers of PD, since they are ubiquitously found among confirmed patients and occur much earlier than motor symptoms. These gastrointestinal dysfunctions include constipation and inflammation of the gut mucosa and the most distinctive pathologic features associated are the loss of neurons of the enteric nervous system and the generation of Lewy bodies in the gut. Moreover, emerging evidence has recently shown a pivotal role of gut microbiota in triggering the development of PD in genetically predisposed individuals. Of note, PD has been positively correlated with inflammatory bowel diseases, a group of disorders involving a T-cell driven inflammation of gut mucosa, which is strongly dependent in the composition of gut microbiota. Here we raised the hypothesis that T-cell driven inflammation, which mediates dopaminergic neurodegeneration in PD, is triggered in the gut mucosa. Accordingly, we discuss how structural components of commensal bacteria or how different mediators produced by gut-microbiota, including short-chain fatty acids and dopamine, may affect the behaviour of T-cells, triggering the development of T-cell responses against Lewy bodies, initially confined to the gut mucosa but later extended to the brain.
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Encéfalo/metabolismo , Neuronas Dopaminérgicas/patología , Microbioma Gastrointestinal/inmunología , Tracto Gastrointestinal/inmunología , Inflamación/inmunología , Enfermedad de Parkinson/inmunología , Linfocitos T/inmunología , Encéfalo/patología , Humanos , Inmunidad Celular , NeuroinmunomodulaciónRESUMEN
Neuroinflammation involves the activation of glial cells, which is associated to the progression of neurodegeneration in Parkinson's disease. Recently, we and other researchers demonstrated that dopamine receptor D3 (D3R)-deficient mice are completely refractory to neuroinflammation and consequent neurodegeneration associated to the acute intoxication with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In this study we examined the therapeutic potential and underlying mechanism of a D3R-selective antagonist, PG01037, in mice intoxicated with a chronic regime of administration of MPTP and probenecid (MPTPp). Biodistribution analysis indicated that intraperitoneally administered PG01037 crosses the blood-brain barrier and reaches the highest concentration in the brain 40 min after the injection. Furthermore, the drug was preferentially distributed to the brain in comparison to the plasma. Treatment of MPTPp-intoxicated mice with PG01037 (30 mg/kg, administrated twice a week for five weeks) attenuated the loss of dopaminergic neurons in the substantia nigra pars compacta, as evaluated by stereological analysis, and the loss of striatal dopaminergic terminals, as determined by densitometric analyses of tyrosine hydroxylase and dopamine transporter immunoreactivities. Accordingly, the treatment resulted in significant improvement of motor performance of injured animals. Interestingly, the therapeutic dose of PG01037 exacerbated astrogliosis and resulted in increased ramification density of microglial cells in the striatum of MPTPp-intoxicated mice. Further analyses suggested that D3R expressed in astrocytes favours a beneficial astrogliosis with anti-inflammatory consequences on microglia. Our findings indicate that D3R-antagonism exerts a therapeutic effect in parkinsonian animals by reducing the loss of dopaminergic neurons in the nigrostriatal pathway, alleviating motor impairments and modifying the pro-inflammatory phenotype of glial cells.
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Benzamidas/administración & dosificación , Neuronas Dopaminérgicas/efectos de los fármacos , Encefalitis/prevención & control , Fármacos Neuroprotectores/administración & dosificación , Trastornos Parkinsonianos/prevención & control , Piridinas/administración & dosificación , Receptores de Dopamina D3/antagonistas & inhibidores , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Benzamidas/sangre , Benzamidas/farmacología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/patología , Neuronas Dopaminérgicas/patología , Encefalitis/etiología , Masculino , Ratones , Ratones Endogámicos C57BL , Microglía/efectos de los fármacos , Actividad Motora/efectos de los fármacos , Fármacos Neuroprotectores/sangre , Fármacos Neuroprotectores/farmacología , Enfermedad de Parkinson/complicaciones , Enfermedad de Parkinson/prevención & control , Trastornos Parkinsonianos/complicaciones , Porción Compacta de la Sustancia Negra/efectos de los fármacos , Porción Compacta de la Sustancia Negra/patología , Piridinas/sangre , Piridinas/farmacología , Receptores de Dopamina D3/metabolismoRESUMEN
Dopamine receptors have been described in T-cells, however their signalling pathways coupled remain unknown. Since cAMP and ERKs play key roles regulating T-cell physiology, we aim to determine whether cAMP and ERK1/2-phosphorylation are modulated by dopamine receptor 3 (D3R) and D5R, and how this modulation affects CD4(+) T-cell activation and differentiation. Our pharmacologic and genetic evidence shows that D3R-stimulation reduced cAMP levels and ERK2-phosphorylation, consequently increasing CD4(+) T-cell activation and Th1-differentiation, respectively. Moreover, D5R expression reinforced TCR-triggered ERK1/2-phosphorylation and T-cell activation. In conclusion, these findings demonstrate how D3R and D5R modulate key signalling pathways affecting CD4(+) T-cell activation and Th1-differentiation.
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Antígenos CD4/metabolismo , Diferenciación Celular/fisiología , AMP Cíclico/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Receptores de Dopamina D3/metabolismo , Receptores de Dopamina D5/metabolismo , Linfocitos T/fisiología , Animales , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/genética , Dopaminérgicos/farmacología , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Activación Enzimática/genética , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/genética , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Ionomicina/farmacología , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación/efectos de los fármacos , Fosforilación/genética , Receptores de Dopamina D3/genética , Receptores de Dopamina D5/genética , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Linfocitos T/efectos de los fármacosRESUMEN
Neuroinflammation constitutes a fundamental process involved in the progression of several neurodegenerative disorders, such as Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis and multiple sclerosis. Microglial cells play a central role in neuroinflammation, promoting neuroprotective or neurotoxic microenvironments, thus controlling neuronal fate. Acquisition of different microglial functions is regulated by intercellular interactions with neurons, astrocytes, the blood-brain barrier, and T-cells infiltrating the central nervous system. In this study, an overview of the regulation of microglial function mediated by different intercellular communications is summarised and discussed. Afterward, we focus in T-cell-mediated regulation of neuroinflammation involved in neurodegenerative disorders.
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Microglía/inmunología , Neuritis/inmunología , Enfermedades Neurodegenerativas/inmunología , Neuroinmunomodulación/inmunología , Animales , Barrera Hematoencefálica/inmunología , Humanos , Tolerancia Inmunológica/inmunologíaRESUMEN
Emerging evidence has demonstrated that CD4(+) T cells infiltrate into the substantia nigra (SN) in Parkinson's disease (PD) patients and in animal models of PD. SN-infiltrated CD4(+) T cells bearing inflammatory phenotypes promote microglial activation and strongly contribute to neurodegeneration of dopaminergic neurons. Importantly, altered expression of dopamine receptor D3 (D3R) in PBLs from PD patients has been correlated with disease severity. Moreover, pharmacological evidence has suggested that D3R is involved in IFN-γ production by human CD4(+) T cells. In this study, we examined the role of D3R expressed on CD4(+) T cells in neurodegeneration of dopaminergic neurons in the SN using a mouse model of PD. Our results show that D3R-deficient mice are strongly protected against loss of dopaminergic neurons and microglial activation during 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD. Notably, D3R-deficient mice become susceptible to MPTP-induced neurodegeneration and microglial activation upon transfer of wild-type (WT) CD4(+) T cells. Furthermore, RAG1 knockout mice, which are devoid of T cells and are resistant to MPTP-induced neurodegeneration, become susceptible to MPTP-induced loss of dopaminergic neurons when reconstituted with WT CD4(+) T cells but not when transferred with D3R-deficient CD4(+) T cells. In agreement, experiments analyzing activation and differentiation of CD4(+) T cells revealed that D3R favors both T cell activation and acquisition of the Th1 inflammatory phenotype. These findings indicate that D3R expressed on CD4(+) T cells plays a fundamental role in the physiopathology of MPTP-induced PD in a mouse model.
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Linfocitos T CD4-Positivos/metabolismo , Neuronas Dopaminérgicas/patología , Proteínas de Homeodominio/genética , Enfermedad de Parkinson/patología , Receptores de Dopamina D3/metabolismo , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina , Traslado Adoptivo , Animales , Linfocitos T CD4-Positivos/inmunología , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Neuronas Dopaminérgicas/inmunología , Inflamación/inmunología , Interferón gamma/biosíntesis , Activación de Linfocitos/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Microglía/metabolismo , Degeneración Nerviosa/metabolismo , Enfermedad de Parkinson/metabolismo , Receptores de Dopamina D3/biosíntesis , Receptores de Dopamina D3/genética , Bazo , Sustancia Negra/inmunología , Sustancia Negra/metabolismo , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
Dendritic cells (DCs) are responsible for priming T cells and for promoting their differentiation from naive T cells into appropriate effector cells. Emerging evidence suggests that neurotransmitters can modulate T cell-mediated immunity. However, the involvement of specific neurotransmitters or receptors remains poorly understood. In this study, we analyzed the role of dopamine in the regulation of DC function. We found that DCs express dopamine receptors as well as the machinery necessary to synthesize, store, and degrade dopamine. Notably, the expression of D5R decreased upon LPS-induced DC maturation. Deficiency of D5R on the surface of DCs impaired LPS-induced IL-23 and IL-12 production and consequently attenuated the activation and proliferation of Ag-specific CD4(+) T cells. To determine the relevance of D5R expressed on DCs in vivo, we studied the role of this receptor in the modulation of a CD4(+) T cell-driven autoimmunity model. Importantly, D5R-deficient DCs prophylactically transferred into wild-type recipients were able to reduce the severity of experimental autoimmune encephalomyelitis. Furthermore, mice transferred with D5R-deficient DCs displayed a significant reduction in the percentage of Th17 cells infiltrating the CNS without differences in the percentage of Th1 cells compared with animals transferred with wild-type DCs. Our findings demonstrate that by contributing to CD4(+) T cell activation and differentiation to Th17 phenotype, D5R expressed on DCs is able to modulate the development of an autoimmune response in vivo.