RESUMO
In animals, the brain regulates feeding behavior in response to local energy demands of peripheral tissues, which secrete orexigenic and anorexigenic hormones. Although skeletal muscle is a key peripheral tissue, it remains unknown whether muscle-secreted hormones regulate feeding. In Drosophila, we found that decapentaplegic (dpp), the homolog of human bone morphogenetic proteins BMP2 and BMP4, is a muscle-secreted factor (a myokine) that is induced by nutrient sensing and that circulates and signals to the brain. Muscle-restricted dpp RNAi promotes foraging and feeding initiation, whereas dpp overexpression reduces it. This regulation of feeding by muscle-derived Dpp stems from modulation of brain tyrosine hydroxylase (TH) expression and dopamine biosynthesis. Consistently, Dpp receptor signaling in dopaminergic neurons regulates TH expression and feeding initiation via the downstream transcriptional repressor Schnurri. Moreover, pharmacologic modulation of TH activity rescues the changes in feeding initiation due to modulation of dpp expression in muscle. These findings indicate that muscle-to-brain endocrine signaling mediated by the myokine Dpp regulates feeding behavior.
Assuntos
Proteínas de Drosophila/metabolismo , Drosophila/genética , Drosophila/metabolismo , Comportamento Alimentar/fisiologia , Animais , Encéfalo/fisiologia , Proteínas de Ligação a DNA/metabolismo , Dopaminérgicos/farmacologia , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/fisiologia , Drosophila/enzimologia , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Levodopa/farmacologia , Monoiodotirosina/farmacologia , Transdução de Sinais , Fatores de Transcrição/metabolismo , Tirosina 3-Mono-Oxigenase/genética , Regulação para CimaRESUMO
The hypothalamus is a key link in neuroendocrine regulations, which are provided by neuropeptides and dopamine. Until the late 1980 s, it was believed that, along with peptidergic neurons, hypothalamus contained dopaminergic neurons. Over time, it has been shown that besides dopaminergic neurons expressing the dopamine transporter and dopamine-synthesizing enzymes - tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC) - the hypothalamus contains neurons expressing only TH, only AADC, both enzymes or only dopamine transporter. The end secretory product of TH neurons is L-3,4-dihydroxyphenylalanine, while that of AADC neurons and bienzymatic neurons lacking the dopamine transporter is dopamine. During ontogenesis, especially in the perinatal period, monoenzymatic neurons predominate in the hypothalamic neuroendocrine centers. It is assumed that L-3,4-dihydroxyphenylalanine and dopamine are released into the neuropil, cerebral ventricles, and blood vessels, participating in the regulation of target cell differentiation in the perinatal period and the functioning of target cells in adulthood.
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Chronic intermittent hypoxia (CIH, a model for sleep apnoea) is a major risk factor for several cardiovascular diseases. Autonomic imbalance (sympathetic overactivity and parasympathetic withdrawal) has emerged as a causal contributor of CIH-induced cardiovascular disease. Previously, we showed that CIH remodels the parasympathetic pathway. However, whether CIH induces remodelling of the cardiac sympathetic innervation remains unknown. Mice (male, C57BL/6J, 2-3 months) were exposed to either room air (RA, 21% O2 ) or CIH (alternating 21% and 5.7% O2 , every 6 min, 10 h day-1 ) for 8-10 weeks. Flat-mounts of their left and right atria were immunohistochemically labelled for tyrosine hydroxylase (TH, a sympathetic marker). Using a confocal microscope (or fluorescence microscope) and Neurlocudia 360 digitization and tracing system, we scanned both the left and right atria and quantitatively analysed the sympathetic axon density in both groups. The segmentation data was mapped onto a 3D mouse heart scaffold. Our findings indicated that CIH significantly remodelled the TH immunoreactive (-IR) innervation of the atria by increasing its density at the sinoatrial node, the auricles and the major veins attached to the atria (P < 0.05, n = 7). Additionally, CIH increased the branching points of TH-IR axons and decreased the distance between varicosities. Abnormal patterns of TH-IR axons around intrinsic cardiac ganglia were also found following CIH. We postulate that the increased sympathetic innervation may further amplify the effects of enhanced CIH-induced central sympathetic drive to the heart. Our work provides an anatomical foundation for the understanding of CIH-induced autonomic imbalance. KEY POINTS: Chronic intermittent hypoxia (CIH, a model for sleep apnoea) causes sympathetic overactivity, cardiovascular remodelling and hypertension. We determined the effect of CIH on sympathetic innervation of the mouse atria. In vivo CIH for 8-10 weeks resulted in an aberrant axonal pattern around the principal neurons within intrinsic cardiac ganglia and an increase in the density, branching point, tortuosity of catecholaminergic axons and atrial wall thickness. Utilizing mapping tool available from NIH (SPARC) Program, the topographical distribution of the catecholaminergic innervation of the atria were integrated into a novel 3D heart scaffold for precise anatomical distribution and holistic quantitative comparison between normal and CIH mice. This work provides a unique neuroanatomical understanding of the pathophysiology of CIH-induced autonomic remodelling.
Assuntos
Hipertensão , Síndromes da Apneia do Sono , Camundongos , Masculino , Animais , Camundongos Endogâmicos C57BL , Átrios do Coração/metabolismo , HipóxiaRESUMO
The nucleus of the solitary tract (NTS) receives direct viscerosensory vagal afferent input that drives autonomic reflexes, neuroendocrine function and modulates behaviour. A subpopulation of NTS neurons project to the nucleus accumbens (NAc); however, the function of this NTS-NAc pathway remains unknown. A combination of neuroanatomical tracing, slice electrophysiology and fibre photometry was used in mice and/or rats to determine how NTS-NAc neurons fit within the viscerosensory network. NTS-NAc projection neurons are predominantly located in the medial and caudal portions of the NTS with 54 ± 7% (mice) and 65 ± 3% (rat) being TH-positive, representing the A2 NTS cell group. In horizontal brainstem slices, solitary tract (ST) stimulation evoked excitatory post-synaptic currents (EPSCs) in NTS-NAc projection neurons. The majority (75%) received low-jitter, zero-failure EPSCs characteristic of monosynaptic ST afferent input that identifies them as second order to primary sensory neurons. We then examined whether NTS-NAc neurons respond to cholecystokinin (CCK, 20 µg/kg ip) in vivo in both mice and rats. Surprisingly, there was no difference in the number of activated NTS-NAc cells between CCK and saline-treated mice. In rats, just 6% of NTS-NAc cells were recruited by CCK. As NTS TH neurons are the primary source for NAc noradrenaline, we measured noradrenaline release in the NAc and showed that NAc noradrenaline levels declined in response to cue-induced reward retrieval but not foot shock. Combined, these findings suggest that high-fidelity afferent information from viscerosensory afferents reaches the NAc. These signals are likely unrelated to CCK-sensitive vagal afferents but could interact with other sensory and higher order inputs to modulate learned appetitive behaviours.
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Despite the advent of combination anti-retroviral therapy (cART), nearly half of people infected with HIV treated with cART still exhibit HIV-associated neurocognitive disorders (HAND). HAND can be worsened by co-morbid opioid use disorder. The basal ganglia are particularly vulnerable to HIV-1 and exhibit higher viral loads and more severe pathology, which can be exacerbated by co-exposure to opioids. Evidence suggests that dopaminergic neurotransmission is disrupted by HIV exposure, however, little is known about whether co-exposure to opioids may alter neurotransmitter levels in the striatum and if this in turn influences behavior. Therefore, we assayed motor, anxiety-like, novelty-seeking, exploratory, and social behaviors, and levels of monoamines and their metabolites following 2 weeks and 2 months of Tat and/or morphine exposure in transgenic mice. Morphine decreased dopamine levels, but significantly elevated norepinephrine, the dopamine metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the serotonin metabolite 5-hydroxyindoleacetic acid, which typically correlated with increased locomotor behavior. The combination of Tat and morphine altered dopamine, DOPAC, and HVA concentrations differently depending on the neurotransmitter/metabolite and duration of exposure but did not affect the numbers of tyrosine hydroxylase-positive neurons in the mesencephalon. Tat exposure increased the latency to interact with novel conspecifics, but not other novel objects, suggesting the viral protein inhibits exploratory behavior initiation in a context-dependent manner. By contrast, and consistent with prior findings that opioid misuse can increase novelty-seeking behavior, morphine exposure increased the time spent exploring a novel environment. Finally, Tat and morphine interacted to affect locomotor activity in a time-dependent manner, while grip strength and rotarod performance were unaffected. Together, our results provide novel insight into the unique effects of HIV-1 Tat and morphine on monoamine neurochemistry that may underlie their divergent effects on motor and exploratory behavior.
Assuntos
Infecções por HIV , HIV-1 , Humanos , Camundongos , Animais , Morfina/farmacologia , Comportamento Exploratório , HIV-1/metabolismo , Dopamina/metabolismo , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Camundongos Transgênicos , Analgésicos Opioides/farmacologia , Ácido Homovanílico , Neurotransmissores , Produtos do Gene tat do Vírus da Imunodeficiência Humana/metabolismoRESUMO
The gene encoding 5'-nucleotidase domain-containing protein 2 (NT5DC2) has been associated with neuropsychiatric disorders related to the abnormality of dopamine activity in the brain. However, its physiological functions remain unclear. In this study, we analyzed the features of NT5DC2 that influence its binding with tyrosine hydroxylase (TH) and its effects on dihydroxyphenylalanine (DOPA) synthesis, using NT5DC2 overexpressed in PC12D cells by the pCMV vector. Western blot analysis revealed that the purified NT5DC2-DYKDDDDK-tag (NT5DC2-tag) protein can bind with the phosphorylated form of recombinant human TH type 1 (rhTH1), apart from the endogenous TH in PC12D cells. Proteomic analysis by mass spectrometry revealed that the purified NT5DC2-tag protein has the potential to bind to 41 proteins with multiple phosphorylation sites in PC12D cells (NT5DC2 binding proteins: positive, 391 sites/41 proteins; and negative, 85 sites/27 proteins). Overexpression of NT5DC2 in PC12D cells decreased DOPA levels in the medium. When the lysate of PC12D cells overexpressing NT5DC2 was incubated at 37 °C, the phosphorylated form of endogenous TH in PC12D cells decreased. This decrease was also detected when phosphorylated rhTH1 was incubated with purified NT5DC2-tag. Overall, our results suggest that NT5DC2 regulates DOPA synthesis by promoting the dephosphorylation of TH, similar to a phosphatase. Therefore, our study provides useful information for understanding various disorders associated with abnormalities in dopamine levels in the brain.
Assuntos
Oxigenases de Função Mista , Tirosina 3-Mono-Oxigenase , Humanos , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Fosforilação , Oxigenases de Função Mista/metabolismo , Dopamina , Proteínas de Transporte/metabolismo , Proteômica , Di-Hidroxifenilalanina/metabolismoRESUMO
Proteostatic regulation of tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine biosynthesis, is crucial for maintaining proper brain neurotransmitter homeostasis. Variants of the TH gene are associated with tyrosine hydroxylase deficiency (THD), a rare disorder with a wide phenotypic spectrum and variable response to treatment, which affects protein stability and may lead to accelerated degradation, loss of TH function and catecholamine deficiency. In this study, we investigated the effects of the TH cofactor tetrahydrobiopterin (BH4) on the stability of TH in isolated protein and in DAn- differentiated from iPSCs from a human healthy subject, as well as from THD patients with the R233H variant in homozygosity (THDA) and R328W and T399M variants in heterozygosity (THDB). We report an increase in TH and dopamine levels, and an increase in the number of TH+ cells in control and THDA cells. To translate this in vitro effect, we treated with BH4 a knock-in THD mouse model with Th variant corresponding to R233H in patients. Importantly, treatment with BH4 significantly improved motor function in these mice, as demonstrated by increased latency on the rotarod test and improved horizontal activity (catalepsy). In conclusion, our study demonstrates the stabilizing effects of BH4 on TH protein levels and function in THD neurons and mice, rescuing disease phenotypes and improving motor outcomes. These findings highlight the therapeutic potential of BH4 as a treatment option for THDA patients with specific variants and provide insights into the modulation of TH stability and its implications for THD management.
Assuntos
Biopterinas , Modelos Animais de Doenças , Neurônios , Fenótipo , Tirosina 3-Mono-Oxigenase , Biopterinas/análogos & derivados , Animais , Humanos , Tirosina 3-Mono-Oxigenase/metabolismo , Camundongos , Neurônios/metabolismo , Dopamina/metabolismo , Masculino , Fenilcetonúrias/tratamento farmacológico , Fenilcetonúrias/genética , Fenilcetonúrias/metabolismo , Feminino , Técnicas de Introdução de GenesRESUMO
Tyrosine hydroxylase (TH) catalyzes hydroxylation of L-tyrosine to L-3,4-dihydroxyphenylalanine, the initial and rate-limiting step in the synthesis of dopamine, noradrenaline, and adrenaline. Mutations in the human TH gene are associated with hereditary motor disorders. The common C886T mutation identified in the mouse Th gene results in the R278H substitution in the enzyme molecule. We investigated the impact of this mutation on the TH activity in the mouse midbrain. The TH activity in the midbrain of Mus musculus castaneus (CAST) mice homozygous for the 886C allele was higher compared to C57BL/6 and DBA/2 mice homozygous for the 886T allele. Notably, this difference in the enzyme activity was not associated with changes in the Th gene mRNA levels and TH protein content. Analysis of the TH activity in the midbrain in mice from the F2 population obtained by crossbreeding of C57BL/6 and CAST mice revealed that the 886C allele is associated with a high TH activity. Moreover, this allele showed complete dominance over the 886T allele. However, the C886T mutation did not affect the levels of TH protein in the midbrain. These findings demonstrate that the C886T mutation is a major genetic factor determining the activity of TH in the midbrain of common laboratory mouse strains. Moreover, it represents the first common spontaneous mutation in the mouse Th gene whose influence on the enzyme activity has been demonstrated. These results will help to understand the role of TH in the development of adaptive and pathological behavior, elucidate molecular mechanisms regulating the activity of TH, and explore pharmacological agents for modulating its function.
Assuntos
Camundongos Endogâmicos C57BL , Tirosina 3-Mono-Oxigenase , Animais , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Camundongos , Mutação , Encéfalo/metabolismo , Camundongos Endogâmicos DBA , Mesencéfalo/metabolismo , Mesencéfalo/enzimologia , Masculino , AlelosRESUMO
Autism spectrum disorder (ASD) is characterized by deficits in social interaction and communication and repetitive and restricted behaviors. Sex dimorphism in the brain, including midbrain dopaminergic circuits, can explain differences in social behavior impairment and stereotypic behaviors between male and female individuals with ASD. These abnormal patterns may be due to alterations in dopamine synthesis in the ventral tegmental area (VTA) and substantia nigra (SN). We used an autism-like mouse model by prenatal valproic acid (VPA) exposure. CD1 pregnant female mice were injected with 500 mg/kg VPA or 0.9% NaCl as a vehicle on gestational day 12.5. In the offspring, on postnatal day 31, we examined the social and repetitive behaviors and the number of tyrosine hydroxylase (TH)-positive cells in VTA and SN by sex. Male VPA mice showed impaired social behavior and increased repetitive behaviors when compared to male vehicles. In females, we did not find statistically significant differences in social or repetitive behaviors between the groups. Male VPA mice had fewer TH+ cells in the SN than control-vehicle mice. Interestingly, no cellular changes were observed between females. This study supports the notion that sex dimorphism of certain brain regions is involved in the etiopathogenesis and clinical presentation of ASD.
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Transtorno do Espectro Autista , Transtorno Autístico , Efeitos Tardios da Exposição Pré-Natal , Gravidez , Camundongos , Feminino , Masculino , Animais , Humanos , Ácido Valproico/farmacologia , Caracteres Sexuais , Neurônios Dopaminérgicos/patologia , Comportamento Social , Substância Negra/patologia , Modelos Animais de Doenças , Efeitos Tardios da Exposição Pré-Natal/patologia , Comportamento Animal/fisiologiaRESUMO
OBJECTIVE: Levodopa (L-DOPA) is the primary treatment for Parkinson's disease (PD). Nevertheless, the underlying mechanism of its action is not entirely learned. This study aims to probe the action of L-DOPA on NLR pyrin domain containing 3 (NLRP3) inflammasome activation and tyrosine hydroxylase (TH) levels in the striatum (STR) and substantia nigra (SN) of mice with PD symptoms. METHODS: PD was simulated by administering 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 25 mg/kg/d) to induce mice, followed by L-DOPA (8 mg/kg/d) treatment. The behavioral performance of the mice was assessed using the pole test, balance beam, and rotarod test. After euthanasia with 120 mg/kg sodium pentobarbital, STR and SN were collected for evaluation of protein level of TH, NLR pyrin domain containing 3 (NLRP3), ASC and Cleaved caspase-1 using Western blot and mRNA levels of TH, inflammatory factors IL-1ß and IL-18 using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). RESULTS: Treatment with L-DOPA significantly ameliorated the behavioral deficits caused by MPTP in mice with PD symptoms. L-DOPA administration resulted in reduced levels of apoptosis-associated speck-like protein containing a CARD (caspase recruitment domain) (ASC), NLRP3, and Cleaved caspase-1 protein levels, and decreased mRNA levels of IL-1ß and IL-18 in the STR and SN. L-DOPA increased the TH mRNA and TH protein levels, while suppressing NLRP3 inflammasome activation in the STR and SN of mice with PD symptoms. CONCLUSIONS: L-DOPA improves the behavioral deficits in mice with PD symptoms possibly by suppressing NLRP3 inflammasome activation and increasing TH levels in the STR and SN TH levels. These findings provide further perceptions into the property of L-DOPA in PD.
Assuntos
Doença de Parkinson , Camundongos , Animais , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Levodopa/farmacologia , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Interleucina-18/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , Substância Negra/metabolismo , RNA Mensageiro/metabolismo , Caspases/metabolismo , Camundongos Endogâmicos C57BL , Modelos Animais de DoençasRESUMO
The striped stem borer, Chilo suppressalis (Walker), a notorious pest infesting rice, has evolved a high level of resistance to many commonly used insecticides. In this study, we investigate whether tyrosine hydroxylase (TH), which is required for larval development and cuticle tanning in many insects, could be a potential target for the control of C. suppressalis. We identified and characterized the full-length cDNA (CsTH) of C. suppressalis. The complete open reading frame of CsTH (MW690914) was 1683 bp in length, encoding a protein of 560 amino acids. Within the first to the sixth larval instars, CsTH was high in the first day just after molting, and lower in the ensuing days. From the wandering stage to the adult stage, levels of CSTH began to rise and reached a peak at the pupal stage. These patterns suggested a role for the gene in larval development and larval-pupal cuticle tanning. When we injected dsCsTH or 3-iodotyrosine (3-IT) as a TH inhibitor or fed a larva diet supplemented with 3-IT, there were significant impairments in larval development and larval-pupal cuticle tanning. Adult emergence was severely impaired, and most adults died. These results suggest that CsTH might play a critical role in larval development as well as larval-pupal tanning and immunity in C. suppressalis, and this gene could form a potential novel target for pest control.
Assuntos
Inseticidas , Mariposas , Oryza , Animais , Larva/genética , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Pupa , Mariposas/metabolismo , Oryza/metabolismoRESUMO
Amphetamines (Amph) are psychostimulants broadly used as physical and cognitive enhancers. However, the long-term effects of prenatal exposure to Amph have been poorly investigated. Here, we show that continuous exposure to Amph during early development induces long-lasting changes in histone methylation at the C. elegans tyrosine hydroxylase (TH) homolog cat-2 and the vesicular monoamine transporter (VMAT) homologue cat-1 genes. These Amph-induced histone modifications are correlated with enhanced expression and function of CAT-2/TH and higher levels of dopamine, but decreased expression of CAT-1/VMAT in adult animals. Moreover, while adult animals pre-exposed to Amph do not show obvious behavioral defects, when challenged with Amph they exhibit Amph hypersensitivity, which is associated with a rapid increase in cat-2/TH mRNA. Because C. elegans has helped reveal neuronal and epigenetic mechanisms that are shared among animals as diverse as roundworms and humans, and because of the evolutionary conservation of the dopaminergic response to psychostimulants, data collected in this study could help us to identify the mechanisms through which Amph induces long-lasting physiological and behavioral changes in mammals.
Assuntos
Anfetamina , Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Desenvolvimento Embrionário , Tirosina 3-Mono-Oxigenase , Proteínas Vesiculares de Transporte de Monoamina , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/metabolismo , Proteínas Vesiculares de Transporte de Monoamina/metabolismo , Proteínas Vesiculares de Transporte de Monoamina/genética , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Anfetamina/farmacologia , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Desenvolvimento Embrionário/efeitos dos fármacos , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Dopamina/metabolismo , Epigênese Genética/efeitos dos fármacosRESUMO
The mechanistic influences of dopamine (DA) signaling and impact on motor function are nearly always interpreted from changes in nigrostriatal neuron terminals in striatum. This is a standard practice in studies of human Parkinson's disease (PD) and aging and related animal models of PD and aging-related parkinsonism. However, despite dozens of studies indicating an ambiguous relationship between changes in striatal DA signaling and motor phenotype, this perseverating focus on striatum continues. Although DA release in substantia nigra (SN) was first reported almost 50 years ago, assessment of nigral DA signaling changes in relation to motor function is rarely considered. Whereas DA signaling has been well-characterized in striatum at all five steps of neurotransmission (biosynthesis and turnover, storage, release, reuptake, and post-synaptic binding) in the nigrostriatal pathway, the depth of such interrogations in the SN, outside of cell counts, is sparse. However, there is sufficient evidence that these steps in DA neurotransmission in the SN are operational and regulated autonomously from striatum and are present in human PD and aging and related animal models. To complete our understanding of how nigrostriatal DA signaling affects motor function, it is past time to include interrogation of nigral DA signaling. This brief review highlights evidence that changes in nigral DA signaling at each step in DA neurotransmission are autonomous from those in striatum and changes in the SN alone can influence locomotor function. Accordingly, for full characterization of how nigrostriatal DA signaling affects locomotor activity, interrogation of DA signaling in SN is essential.
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Dopamina , Doença de Parkinson , Animais , Humanos , Transdução de Sinais , Transmissão Sináptica , Corpo Estriado , Substância NegraRESUMO
The kallikrein-kinin system is a versatile regulatory network implicated in various biological processes encompassing inflammation, nociception, blood pressure control, and central nervous system functions. Its physiological impact is mediated through G-protein-coupled transmembrane receptors, specifically the B1 and B2 receptors. Dopamine, a key catecholamine neurotransmitter widely distributed in the CNS, plays a crucial role in diverse physiological functions including motricity, reward, anxiety, fear, feeding, sleep, and arousal. Notably, the potential physical interaction between bradykinin and dopaminergic receptors has been previously documented. In this study, we aimed to explore whether B2R modulation in catecholaminergic neurons influences the dopaminergic pathway, impacting behavioral, metabolic, and motor aspects in both male and female mice. B2R ablation in tyrosine hydroxylase cells reduced the body weight and lean mass without affecting body adiposity, substrate oxidation, locomotor activity, glucose tolerance, or insulin sensitivity in mice. Moreover, a B2R deficiency in TH cells did not alter anxiety levels, exercise performance, or motor coordination in female and male mice. The concentrations of monoamines and their metabolites in the substantia nigra and cortex region were not affected in knockout mice. In essence, B2R deletion in TH cells selectively influenced the body weight and composition, leaving the behavioral and motor aspects largely unaffected.
Assuntos
Receptor B2 da Bradicinina , Tirosina 3-Mono-Oxigenase , Camundongos , Masculino , Feminino , Animais , Receptor B2 da Bradicinina/genética , Receptor B2 da Bradicinina/metabolismo , Tirosina 3-Mono-Oxigenase/genética , Bradicinina/farmacologia , Receptor B1 da Bradicinina/metabolismo , Peso Corporal , Camundongos KnockoutRESUMO
There are currently no disease-modifying therapies for Parkinson's disease (PD), a progressive neurodegenerative disorder associated with dopaminergic neuronal loss. There is increasing evidence that endogenous dopamine (DA) can be a pathological factor in neurodegeneration in PD. Tyrosine hydroxylase (TH) is the key rate-limiting enzyme for DA generation. Drugs that inhibit TH, such as alpha-methyltyrosine (α-MT), have recently been shown to protect against neurodegeneration in various PD models. DA receptor agonists can activate post-synaptic DA receptors to alleviate DA-deficiency-induced PD symptoms. However, DA receptor agonists have no therapeutic effects against neurodegeneration. Thus, a combination therapy with DA receptor agonists plus TH inhibitors may be an attractive therapeutic approach. TH inhibitors can protect and promote the survival of remaining dopaminergic neurons in PD patients' brains, whereas DA receptor agonists activate post-synaptic DA receptors to alleviate PD symptoms. Additionally, other PD drugs, such as N-acetylcysteine (NAC) and anticholinergic drugs, may be used as adjunctive medications to improve therapeutic effects. This multi-drug cocktail may represent a novel strategy to protect against progressive dopaminergic neurodegeneration and alleviate PD disease progression.
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Agonistas de Dopamina , Doença de Parkinson , Tirosina 3-Mono-Oxigenase , Animais , Humanos , Dopamina/metabolismo , Agonistas de Dopamina/uso terapêutico , Agonistas de Dopamina/farmacologia , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Quimioterapia Combinada , Inibidores Enzimáticos/uso terapêutico , Inibidores Enzimáticos/farmacologia , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Tirosina 3-Mono-Oxigenase/antagonistas & inibidores , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Physiology and behavior are structured temporally to anticipate daily cycles of light and dark, ensuring fitness and survival. Neuromodulatory systems in the brain-including those involving serotonin and dopamine-exhibit daily oscillations in neural activity and help shape circadian rhythms. Disrupted neuromodulation can cause circadian abnormalities that are thought to underlie several neuropsychiatric disorders, including bipolar mania and schizophrenia, for which a mechanistic understanding is still lacking. Here, we show that genetically depleting serotonin in Tph2 knockout mice promotes manic-like behaviors and disrupts daily oscillations of the dopamine biosynthetic enzyme tyrosine hydroxylase (TH) in midbrain dopaminergic nuclei. Specifically, while TH mRNA and protein levels in the Substantia Nigra (SN) and Ventral Tegmental Area (VTA) of wild-type mice doubled between the light and dark phase, TH levels were high throughout the day in Tph2 knockout mice, suggesting a hyperdopaminergic state. Analysis of TH expression in striatal terminal fields also showed blunted rhythms. Additionally, we found low abundance and blunted rhythmicity of the neuropeptide cholecystokinin (Cck) in the VTA of knockout mice, a neuropeptide whose downregulation has been implicated in manic-like states in both rodents and humans. Altogether, our results point to a previously unappreciated serotonergic control of circadian dopamine signaling and propose serotonergic dysfunction as an upstream mechanism underlying dopaminergic deregulation and ultimately maladaptive behaviors.
Assuntos
Ritmo Circadiano , Dopamina , Camundongos Knockout , Serotonina , Triptofano Hidroxilase , Tirosina 3-Mono-Oxigenase , Área Tegmentar Ventral , Animais , Serotonina/metabolismo , Camundongos , Ritmo Circadiano/fisiologia , Dopamina/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , Tirosina 3-Mono-Oxigenase/genética , Triptofano Hidroxilase/genética , Triptofano Hidroxilase/metabolismo , Triptofano Hidroxilase/deficiência , Área Tegmentar Ventral/metabolismo , Colecistocinina/metabolismo , Colecistocinina/genética , Neurônios Dopaminérgicos/metabolismo , Masculino , Substância Negra/metabolismo , Camundongos Endogâmicos C57BL , Transtorno Bipolar/metabolismo , Transtorno Bipolar/genéticaRESUMO
Studying the initial molecular mechanisms of the pathogenesis of Parkinson's disease (PD), primarily in the nigrostriatal dopaminergic system, is one of the priorities in neurology. Of particular interest is elucidating these mechanisms in the preclinical stage of PD, which lasts decades before diagnosis and is therefore not available for study in patients. Therefore, our main goal was to study the initial molecular mechanisms of the pathogenesis of PD in the striatum, the key center for dopamine regulation in motor function, in a mouse model of the earliest preclinical stage of PD, from 1 to 24 h after the administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). It was shown that the content of tyrosine hydroxylase (TH), the first enzyme in dopamine synthesis, does not change within 6 h after the administration of MPTP, but decreases after 24 h. In turn, TH activity increases after 1 h, decreases after 3 h, remains at the control level after 6 h, and decreases 24 h after the administration of MPTP. The concentration of dopamine in the striatum gradually decreases after MPTP administration, despite a decrease in its degradation. The identified initial molecular mechanisms of PD pathogenesis are considered as potential targets for the development of preventive neuroprotective treatment.
Assuntos
Síndromes Neurotóxicas , Doença de Parkinson , Animais , Camundongos , Humanos , Dopamina/metabolismo , Doença de Parkinson/patologia , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina , Substância Negra/metabolismo , Modelos Animais de Doenças , Corpo Estriado/metabolismo , Síndromes Neurotóxicas/patologia , Tirosina 3-Mono-Oxigenase/metabolismo , Camundongos Endogâmicos C57BLRESUMO
Parkinson's disease (PD) is the second most common progressive neurodegenerative disease characterized by the presence of dopaminergic neuronal loss and motor disorders. PD dementia (PDD) is a cognitive disorder that affects many PD patients. We have previously demonstrated the proinflammatory role of the glia maturation factor (GMF) in neuroinflammation and neurodegeneration in AD, PD, traumatic brain injury (TBI), and experimental autoimmune encephalomyelitis (EAE) in human brains and animal models. The purpose of this study was to investigate the expression of the GMF in the human PDD brain. We analyzed the expression pattern of the GMF protein in conjunction with amyloid plaques (APs) and neurofibrillary tangles (NFTs) in the substantia nigra (SN) and striatum of PDD brains using immunostaining. We detected a large number of GMF-positive glial fibrillary acidic protein (GFAP) reactive astrocytes, especially abundant in areas with degenerating dopaminergic neurons within the SN and striatum in PDD. Additionally, we observed excess levels of GMF in glial cells in the vicinity of APs, and NFTs in the SN and striatum of PDD and non-PDD patients. We found that the majority of GMF-positive immunoreactive glial cells were co-localized with GFAP-reactive astrocytes. Our findings suggest that the GMF may be involved in the pathogenesis of PDD.
Assuntos
Demência , Encefalomielite Autoimune Experimental , Fator de Maturação da Glia , Doenças Neurodegenerativas , Doença de Parkinson , Animais , Humanos , Encéfalo , Fator de Maturação da Glia/genéticaRESUMO
INTRODUCTION: Parkinson's disease (PD) is the most common neurodegenerative disease worldwide. Studies have shown that insulin-like growth factor-binding protein 5 (IGFBP5) may contribute to methamphetamine-induced neurotoxicity and neuronal apoptosis in PC-12 cells and rat striatum. Here, we studied the expression and role of IGFBP5 in the 6-OHDA-toxicant model of PD. METHODS: PC-12 and SH-SY5Y cells were exposed to 50 µ
Assuntos
Apoptose , Proteínas Hedgehog , Proteína 5 de Ligação a Fator de Crescimento Semelhante à Insulina , Oxidopamina , Doença de Parkinson , Transdução de Sinais , Animais , Proteínas Hedgehog/metabolismo , Ratos , Apoptose/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Humanos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Modelos Animais de Doenças , Masculino , Células PC12 , Ratos Sprague-DawleyRESUMO
In order to study the neuroprotective mechanism of cinnamaldehyde on reserpine-induced Parkinson's disease(PD) rat models, 72 male Wistar rats were randomly divided into blank group, model group, Madopar group, and cinnamaldehyde high-, medium-, and low-dose groups. Except for the blank group, the other groups were intraperitoneally injected with reserpine of 0.1 mg·kg~(-1) once every other morning, and cinnamaldehyde and Madopar solutions were gavaged every afternoon. Open field test, rotarod test, and oral chewing movement evaluation were carried out in the experiment. The brain was taken and fixed. The positive expression of dopamine receptor D1(DRD1) was detected by TSA, and the changes in neurotransmitters such as dopamine(DA) and 3,4-dihydroxyphenylacetic acid(DOPAC) in the brain were detected by enzyme-linked immunosorbent assay(ELISA). The protein and mRNA expression levels of tyrosine hydroxylase(TH) and α-synuclein(α-Syn) in substantia nigra(SN) were detected by RT-PCR and Western blot. The results showed that after the injection of reserpine, the hair color of the model group became yellow and dirty; the arrest behavior was weakened, and the body weight was reduced. The spontaneous movement and exploration behavior were reduced, and the coordination exercise ability was decreased. The number of oral chewing was increased, but the cognitive ability was decreased, and the proportion of DRD1 positive expression area in SN was decreased. The expression of TH protein and mRNA was down-regulated, and that of α-Syn protein and mRNA was up-regulated. After cinnamaldehyde intervention, it had an obvious curative effect on PD model animals. The spontaneous movement behavior, the time of staying in the rod, the time of movement, the distance of movement, and the number of standing times increased, and the number of oral chewing decreased. The proportion of DRD1 positive expression area in SN increased, and the protein and mRNA expression levels of α-Syn were down-regulated. The protein and mRNA expression levels of TH were up-regulated. In addition, the levels of DA, DOPAC, and homovanillic acid(HVA) neurotransmitters in the brain were up-regulated. This study can provide a new experimental basis for clinical treatment and prevention of PD.