RESUMO
Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor produced locally in the central nervous system which can promote axonal regeneration, protect motoneurons, and inhibit neuroinflammation. In this study, we used the zebrafish spinal transection model to investigate whether IGF-1 plays an important role in the recovery of motor function. Unlike mammals, zebrafish can regenerate axons and restore mobility in remarkably short period after spinal cord transection. Quantitative real-time PCR and immunofluorescence showed decreased IGF-1 expression in the lesion site. Double immunostaining for IGF-1 and Islet-1 (motoneuron marker)/GFAP (astrocyte marker)/Iba-1 (microglia marker) showed that IGF-1 was mainly expressed in motoneurons and was surrounded by astrocyte and microglia. Following administration of IGF-1 morpholino at the lesion site of spinal-transected zebrafish, swimming test showed retarded recovery of mobility, the number of motoneurons was reduced, and increased immunofluorescence density of microglia was caused. Our data suggested that IGF-1 enhances motoneuron survival and inhibits neuroinflammation after spinal cord transection in zebrafish, which suggested that IGF-1 might be involved in the motor recovery.
Assuntos
Traumatismos da Medula Espinal , Peixe-Zebra , Animais , Axônios/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like I/farmacologia , Mamíferos , Neurônios Motores/metabolismo , Regeneração Nervosa/fisiologia , Doenças Neuroinflamatórias , Medula Espinal/metabolismo , Traumatismos da Medula Espinal/metabolismoRESUMO
Evidence suggests constipation precedes motor dysfunction and is the most common gastrointestinal symptom in Parkinson's disease (PD). 5-HT4 receptor (5-HT4R) agonist prucalopride has been approved to treat chronic constipation. Here, we reported intraperitoneal injection of prucalopride for 7 days increased dopamine and decreased dopamine turnover. Prucalopride administration improved motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP)-induced PD mouse models. Prucalopride treatment also ameliorated intestinal barrier impairment and increased IL-6 release in PD model mice. However, prucalopride treatment exerted no impact on JAK2/STAT3 pathway, suggesting that prucalopride may stimulate IL-6 via JAK2/STAT3-independent pathway. In conclusion, prucalopride exerted beneficial effects in MPTP-induced Parkinson's disease mice by attenuating the loss of dopamine, improving motor dysfunction and intestinal barrier.
Assuntos
1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina , Benzofuranos/farmacologia , Benzofuranos/uso terapêutico , Mucosa Intestinal/efeitos dos fármacos , Destreza Motora/efeitos dos fármacos , Doença de Parkinson/prevenção & controle , Doença de Parkinson/fisiopatologia , Animais , Peso Corporal/efeitos dos fármacos , Modelos Animais de Doenças , Dopamina/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Interleucina-6/metabolismo , Mucosa Intestinal/metabolismo , Janus Quinase 2/metabolismo , Intoxicação por MPTP/tratamento farmacológico , Intoxicação por MPTP/fisiopatologia , Intoxicação por MPTP/prevenção & controle , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neostriado/metabolismo , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson Secundária/fisiopatologia , Doença de Parkinson Secundária/prevenção & controle , Fator de Transcrição STAT3/metabolismoRESUMO
Zebrafish is an excellent model to study the mechanisms underlying successful central nervous system (CNS) regeneration. Previous study shows that activating transcription factor 3 (ATF3) promotes neurite outgrowth and is involved in optic nerve regeneration in zebrafish. Here, we used zebrafish model to investigate the role of ATF3 in regeneration following spinal cord injury (SCI). Quantitative polymerase chain reaction (qPCR) and in situ hybridization revealed that ATF3 mRNA levels increased at 12 h and 6 d following SCI. Double labeled immunofluorescence showed that ATF3 expressed in motoneurons. Treatment of anti-sense ATF3 morpholino (MO) inhibited locomotor recovery and decreased axon regeneration of spinal cord injured zebrafish. Further, inhibition of ATF3 up-regulated the expression of inflammatory factors tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). These data suggest that ATF3 could promote locomotor recovery and axon regrowth in zebrafish SCI model possibly by regulating inflammatory response.
Assuntos
Fator 3 Ativador da Transcrição/metabolismo , Regeneração da Medula Espinal , Peixe-Zebra/metabolismo , Fator 3 Ativador da Transcrição/antagonistas & inibidores , Fator 3 Ativador da Transcrição/genética , Animais , Perfilação da Expressão Gênica , Interleucina-1beta/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Necrose Tumoral alfa/genéticaRESUMO
Human spinal cord injury (SCI) usually causes irreversible disability beneath the injured site due to poor neural regeneration. On the contrary, zebrafish show significant regenerative ability after SCI, thus is usually worked as an animal model for studying neuroregeneration. Most of the previous SCI studies focused on the local site of SCI, the supraspinal-derived signals were rarely mentioned. Here we showed that intradiencephalon injection of histamine (HA) inhibited the locomotor recovery in adult zebrafish post-SCI. Immunofluorescence results showed that intradiencephalon HA administration increased the activated microglia 3 days post injury (dpi), promoted the proliferation of radial glial cells at 7 dpi and affected the morphology of radial glial cells at 11 dpi. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) results showed that intradiencephalon HA administration also reduced the expression of neurotrophic factors including brain-derived neurotrophic factor (BDNF) and insulin-like growth factor1 (IGF-1) at the lesion site, however, had no effect on the expression of pro-inflammatory factors such as TNF-alpha and IL-1 beta. Hence, our data suggested that exogenous intradiencephalon HA retarded locomotor recovery in spinal cord injured zebrafish via modulating the repair microenvironment.
Assuntos
Histamina/administração & dosagem , Histamina/farmacologia , Locomoção/efeitos dos fármacos , Traumatismos da Medula Espinal/tratamento farmacológico , Traumatismos da Medula Espinal/fisiopatologia , Peixe-Zebra , Animais , Injeções Intraventriculares , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Traumatismos da Medula Espinal/patologia , Relação Estrutura-Atividade , Peixe-Zebra/fisiologiaRESUMO
Berberine (Ber), an isoquinoline alkaloid, is a potential drug therapy for ulcerative colitis (UC) because of its anti-inflammatory activity, high biological safety, and few side effects. Nevertheless, its clinical application is hindered by its limited water solubility and low bioavailability. Currently, compared to synthetic nanocarriers, exosomes as carriers possess advantages such as low toxicity, high stability, and high specificity. Human placental mesenchymal stem cell-derived exosomes (HplMSC-Exos) have emerged as a promising drug delivery system, offering intrinsic anti-inflammatory and antioxidant activities. Therefore, we engineered MSC-Exos loaded with Ber (Exos-Ber) to enhance the solubility and bioavailability of Ber and for colon targeting, revealing a novel approach for treating UC with natural compounds. Structurally and functionally, Exos-Ber closely resembled unmodified Exos. Both in vitro and in vivo investigations confirmed the antioxidant and anti-inflammatory properties of Exos-Ber. Notably, Exos-Ber exhibited reparative effects on injured epithelial cells and reduced cellular apoptosis. Furthermore, Exos-Ber concurrently demonstrated anti-inflammatory and antioxidant activities, contributing to the mitigation of UC, possibly through its modulation of the MAPK signaling pathway. Overall, our findings demonstrate the potential of Exos-Ber as a promising therapeutic option for alleviating UC, highlighting its capacity to enhance the clinical applicability of Ber.
Assuntos
Berberina , Colite Ulcerativa , Exossomos , Células-Tronco Mesenquimais , Exossomos/metabolismo , Exossomos/química , Colite Ulcerativa/terapia , Colite Ulcerativa/tratamento farmacológico , Colite Ulcerativa/patologia , Berberina/farmacologia , Berberina/química , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Humanos , Animais , Camundongos , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/química , Apoptose/efeitos dos fármacos , Antioxidantes/farmacologia , Antioxidantes/química , Células Cultivadas , Feminino , Tamanho da Partícula , Sobrevivência Celular/efeitos dos fármacosRESUMO
Parkinson's disease (PD) is characterized not only by motor symptoms but also by non-motor dysfunctions, such as olfactory impairment; the cause is not fully understood. Our study suggests that neuronal loss and inflammation in brain regions along the olfactory pathway, such as the olfactory bulb (OB) and the piriform cortex (PC), may contribute to olfactory dysfunction in PD mice, which might be related to the downregulation of the trace amine-associated receptor 1 (TAAR1) in these areas. In the striatum, although only a decrease in mRNA level, but not in protein level, of TAAR1 was detected, bioinformatic analyses substantiated its correlation with PD. Moreover, we discovered that neuronal death and inflammation in the OB and the PC in PD mice might be regulated by TAAR through the Bcl-2/caspase3 pathway. This manifested as a decrease of anti-apoptotic protein Bcl-2 and an increase of the pro-apoptotic protein cleaved caspase3, or through regulating astrocytes activity, manifested as the increase of TAAR1 in astrocytes, which might lead to the decreased clearance of glutamate and consequent neurotoxicity. In summary, we have identified a possible mechanism to elucidate the olfactory dysfunction in PD, positing neuronal damage and inflammation due to apoptosis and astrocyte activity along the olfactory pathway in conjunction with the downregulation of TAAR1.
RESUMO
Inflammatory bowel disease can cause pathological changes of certain organs, including the gut and brain. As the major degradation route of tryptophan (Trp), Kynurenine (Kyn) pathway are involved in multiple pathologies of brain. This study sought to explore the effects of Dextran sulphate sodium (DSS)-induced colitis on serum and brain Trp metabolism (especially the Kyn pathway) and its mechanisms. We induced acute colitis and sub-chronic colitis with 3% DSS and 1% DSS respectively and found more severe intestinal symptoms in acute colitis than sub-chronic colitis. Both of the colitis groups altered Trp-Kyn-Kynurenic acid (Kyna) pathway in serum by regulating the expression of rate-limiting enzyme (IDO-1, KAT2). Interestingly, only 3% DSS group activated Trp-Kyn pathway under the action of metabolic enzymes (IDO-1, TDO-2 and KAT2) in brain. Furthermore, intestinal flora 16S rRNA sequencing showed significantly changes in both DSS-induced colitis groups, including microbial diversity, indicator species, and the abundance of intestinal microflora related to Trp metabolism. The functional pathways of microbiomes involved in inflammation and Trp biosynthesis were elevated after DSS treatment. Moreover, correlation analysis showed a significant association between intestinal flora and Trp metabolism (both in serum and brain). In conclusion, our study suggests that DSS-induced acute colitis causes dysregulation of Trp-Kyn-Kyna pathways of Trp metabolism in serum and brain by affecting rate-limiting enzymes and intestinal flora.
Assuntos
Colite , Microbioma Gastrointestinal , Humanos , Triptofano/metabolismo , RNA Ribossômico 16S , Cinurenina/metabolismo , Colite/patologia , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismo , Encéfalo/metabolismoRESUMO
Accumulative studies suggest that inflammatory bowel disease (IBD) may cause multiple central nervous system (CNS) pathologies. Studies have found that indoleamine-2,3-dioxygenase (IDO, rate-limiting enzyme of the kynurenine (Kyn) pathway) deficient mice were protected from endotoxin induced cognitive impairment, and Kyn administration induced cognitive memory deficits in both control and IDO-deficient mice. However, there is no investigation of the brain Kyn pathway in IBD, thus we investigated whether dextran sulfate sodium (DSS)-induced colitis could cause dysregulation of Kyn pathway in brain, and also in serum. C57BL/6J mice were given drinking water with 2% DSS for 10 consecutive days to induce colitis. In serum, we found significant increase in Kyn and kynurenic acid (Kyna) level, which was regulated by IDO-1 and KAT2 (rate-limiting enzymes of Trp-Kyn-Kyna pathway). Similarly, by analyzing GEO datasets, higher IDO-1 levels in peripheral blood monocytes and colon of UC patients was found. Furthermore, the Kyn pathway was significantly upregulated in the cerebral cortex under the action of IDO-1 after DSS treatment, which ultimately induced the neurotoxic phenotype of astrocytes. To investigate whether gut microbiota is involved in IBD-induced Kyn pathway dysregulation, we performed intestinal flora 16S rRNA sequencing and found that DSS-induced colitis significantly altered the composition and diversity of the gut microbiota. Metabolic function analysis also showed that Tryptophan metabolism, NOD-like receptor signaling pathway and MAPK signaling pathway were significantly up-regulated in the 2% DSS group. A significant association between intestinal flora and Trp metabolism (both in serum and brain) was found by correlation analysis. Overall, this study revealed that DSS-induced colitis causes dysregulation of the Kyn pathway in serum and brain by affecting rate-limiting enzymes and intestinal flora.
Assuntos
Colite , Microbioma Gastrointestinal , Doenças Inflamatórias Intestinais , Animais , Camundongos , Cinurenina/metabolismo , Triptofano/metabolismo , RNA Ribossômico 16S , Camundongos Endogâmicos C57BL , Triptofano Oxigenase/metabolismo , Encéfalo/metabolismo , Colite/metabolismo , Indolamina-Pirrol 2,3,-Dioxigenase/metabolismoRESUMO
Spinal cord injury (SCI) is one of the most common devastating injuries, with little possibility of recovery in humans. However, zebrafish efficiently regenerate functional nervous system tissue after SCI. Therefore, the spinal cord transection model of adult zebrafish was applied to explore the role of ATF6 in neuro-recovery. Activating transcription factor 6 (ATF6) is a type-II transmembrane protein in the endoplasmic reticulum (ER). ATF6 target genes could improve ER homeostasis, which contributes to cytoprotection. Herein, we found that the ATF6 level increased at 12 h and 3 days post SCI, and returned to sham levels at 7 days post SCI. ATF6-expressing motor neurons were present in the central canal of the spinal cord and increased at 12 h post SCI. ATF6 morpholino treatment showed that inhibition of ATF6 delayed locomotor recovery and hindered neuron axon regrowth in SCI zebrafish. Furthermore, we investigated the role of both binding immunoglobulin protein (Bip) and C/EBP homologous transcription factor protein (CHOP), the two target genes of ATF6. We found that Bip expression significantly increased in the spinal cord at 7 days after SCI, which served as a pro-survival chaperone. Our results also showed that CHOP expression significantly decreased in the spinal cord at 7 days after SCI, which was identified as a protein involved in apoptosis. Taken together, our data demonstrate that ATF6 may contribute to the functional recovery after SCI in adult zebrafish, via up-regulation of Bip and down-regulation of CHOP to restore the homeostasis of ER.
Assuntos
Fator 6 Ativador da Transcrição/metabolismo , Traumatismos da Medula Espinal/metabolismo , Regeneração da Medula Espinal , Proteínas de Peixe-Zebra/metabolismo , Fator 6 Ativador da Transcrição/genética , Animais , Axônios/metabolismo , Axônios/fisiologia , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Crescimento Neuronal , Fator de Transcrição CHOP/metabolismo , Peixe-Zebra , Proteínas de Peixe-Zebra/genéticaRESUMO
In strong contrast to limited repair within the mammalian central nervous system, the spinal cord of adult zebrafish is capable of almost complete recovery following injury. Understanding the mechanism underlying neural repair and functional recovery in zebrafish may lead to innovative therapies for human spinal cord injury (SCI). Since neuropeptide Y (NPY) plays a protective role in the pathogenesis of several neurological diseases, in the present study, we evaluated the effects of NPY on neuronal repair and subsequent recovery of motor function in adult zebrafish following SCI. Real-time quantitative PCR (qRT-PCR), in situ hybridization and immunostaining for NPY revealed decreased NPY expression at 12 hours (h), 6 and 21 days (d) after SCI. Double-immunostaining for NPY and islet-1, a motoneuron marker, showed that NPY was expressed in spinal cord motoneurons. Morpholino (MO) treatment for suppressing the expression of NPY inhibited supraspinal axon regrowth and locomotor recovery, in which double-staining for proliferating cell nuclear antigen (PCNA) and islet-1 showed a reduction in motoneuron proliferation. Similarly, a downregulated mRNA level of Y1 receptor of NPY (NPY1R) was also detected at 12 h, 6 and 21 d after injury. Immunostaining for NPY and in situ hybridization for NPY1R revealed that NPY1R was co-localized with NPY. Collectively, the results suggest that NPY expression in motoneurons promotes descending axon regeneration and locomotor recovery in adult zebrafish after SCI, possibly by regulating motoneuron proliferation through activation of NPY1R.
Assuntos
Neuropeptídeo Y/biossíntese , Recuperação de Função Fisiológica/fisiologia , Traumatismos da Medula Espinal/metabolismo , Proteínas de Peixe-Zebra/biossíntese , Animais , Feminino , Expressão Gênica , Masculino , Neurônios Motores/metabolismo , Neuropeptídeo Y/genética , Traumatismos da Medula Espinal/genética , Peixe-Zebra , Proteínas de Peixe-Zebra/genéticaRESUMO
Semaphorins comprise a family of proteins involved in axon guidance during development. Semaphorin4D (Sema4D) has both neuroregenerative and neurorepressive functions, being able to stimulate both axonal outgrowth and growth cone collapse during development, and therefore could play an important role in neurological recovery from traumatic injury. Here, we used a zebrafish spinal cord transection model to study the role of Sema4D in a system capable of neuroregeneration. Real-time qPCR and in situ hybridization showed upregulated Sema4D expression in the acute response phase (within 3days post SCI), and downregulated levels in the chronic response phase (11-21days after SCI). Double-immunostaining for Sema4D and either Islet-1 (motoneuron marker) or Iba-1 (microglial marker) showed that microglia surrounded Sema4D-positive motoneurons along the central canal at 4h post injury (hpi) and 12hpi. Following administration of Sema4D morpholino (MO) to transected zebrafish, double-immunostaining showed that Sema4D-positive motoneurons surrounded by microglia decreased at 7days and 11days compared with standard control MO. Anterograde and retrograde tracing indicate that Sema4D participates in axon regeneration in the spinal cord following spinal cord injury (SCI) in the zebrafish. Swim tracking shows that MO-mediated inhibition of Sema4D retarded the recovery of swimming function when compared to standard control MO. The combined results indicate that Sema4D expression in motoneurons enhances locomotor recovery and axon regeneration, possibly by regulating microglia function, after SCI in adult zebrafish.