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Toll-like receptors (TLRs) are among the main components of the innate immune system. They can detect conserved structures in microorganisms and molecules associated with stress and cellular damage. TLRs are expressed in resident immune cells and both neurons and glial cells of the nervous system. Increasing evidence is emerging on the participation of TLRs not only in the immune response but also in processes of the nervous system, such as neurogenesis and cognition. Below, we present a review of the literature that evaluates the expression and role of TLRs in processes such as neurodevelopment, behavior, cognition, infection, neuroinflammation, and neurodegeneration.
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Sistema Nervoso , Neurogênese , Receptores Toll-Like , Humanos , Receptores Toll-Like/metabolismo , Animais , Sistema Nervoso/metabolismo , Sistema Nervoso/imunologia , Imunidade Inata , Neurônios/metabolismo , Neurônios/imunologia , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/imunologia , Transdução de SinaisRESUMO
Taurine (2-aminoethanesulfonic acid) is a non-protein ß-amino acid essential for cellular homeostasis, with antioxidant, anti-inflammatory, and cytoprotective properties that are crucial for life maintenance. This study aimed to evaluate the effects of taurine administration on hippocampal neurogenesis, neuronal preservation, or reverse damage in rats exposed to forced ethanol consumption in an animal model. Wistar rats were treated with ethanol (EtOH) for a 28-day period (5% in the 1st week, 10% in the 2nd week, and 20% in the 3rd and 4th weeks). Two taurine treatment protocols (300 mg/kg i.p.) were implemented: one during ethanol consumption to analyze neuroprotection, and another after ethanol consumption to assess the reversal of ethanol-induced damage. Overall, the results demonstrated that taurine treatment was effective in protecting against deficits induced by ethanol consumption in the dentate gyrus. The EtOH+TAU group showed a significant increase in cell proliferation (145.8%) and cell survival (54.0%) compared to the EtOH+Sal group. The results also indicated similar effects regarding the reversal of ethanol-induced damage 28 days after the cessation of ethanol consumption. The EtOH+TAU group exhibited a significant increase (41.3%) in the number of DCX-immunoreactive cells compared to the EtOH+Sal group. However, this amino acid did not induce neurogenesis in the tissues of healthy rats, implying that its activity may be contingent upon post-injury stimuli.
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Proteína Duplacortina , Etanol , Hipocampo , Neurogênese , Fármacos Neuroprotetores , Ratos Wistar , Taurina , Animais , Taurina/farmacologia , Neurogênese/efeitos dos fármacos , Masculino , Fármacos Neuroprotetores/farmacologia , Ratos , Hipocampo/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Giro Denteado/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de DoençasRESUMO
Adenomyosis is associated with dysmenorrhea and chronic pelvic pain; however, the triggering mechanisms of painful stimuli and the role of uterine nerve fibers in the manifestation of pain remain poorly understood. The objective of this study was to systematically review the role of uterine nerve fibers' presence and density in the occurrence of pain in patients with adenomyosis. An electronic search was performed using the Embase, PubMed/Medline, and Cochrane databases. We included all studies from inception to November 2023. A total of ten studies that compared uterine biopsies samples of women with and without adenomyosis were included. The biomarker antiprotein gene product 9.5 was decreased or absent in the endometrium of most included women with adenomyosis. None of the included studies observed a difference in neurofilament (NF) staining between the adenomyosis and non-adenomyosis groups. Studies that assessed nerve growth factor (NGF) staining were heterogeneous in design. One study reported no difference in immunohistochemistry staining in any endometrial layer between the adenomyosis and non-adenomyosis groups, while another reported increased staining in the adenomyosis functional endometrial layer, and a third study reported overexpression of NGF, synaptophysin (SYN), and microtubule-associated protein 2 mRNA in focal adenomyosis alone. Preliminary data from poor-quality studies suggest an increase in the uterine density of nerve fibers in patients with adenomyosis. Well-designed studies are essential to assess the cause-and-effect relationship between uterine nerve fibers and pain in patients with adenomyosis.
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Adenomiose , Útero , Humanos , Feminino , Adenomiose/metabolismo , Adenomiose/patologia , Adenomiose/complicações , Útero/inervação , Útero/patologia , Útero/metabolismo , Dor Pélvica/metabolismo , Dor Pélvica/etiologia , Dor Pélvica/patologia , Nervos Periféricos/patologia , Nervos Periféricos/metabolismo , Endométrio/inervação , Endométrio/metabolismo , Endométrio/patologia , Dismenorreia/metabolismoRESUMO
OBJECTIVE: To investigate the effects of cannabidiol (CBD) on emotional and cognitive symptoms in rats with intra-nigral 6-hydroxydopamine (6-OHDA) lesions. METHODS: Adult male Wistar rats received bilateral intranigral 6-OHDA infusions and were tested in a battery of behavioural paradigms to evaluate non-motor symptoms. The brains were obtained to evaluate the effects of CBD on hippocampal neurogenesis. RESULTS: 6-OHDA-lesioned rats exhibited memory impairments and despair-like behaviour in the novelty-suppressed feeding test and forced swim test, respectively. The animals also exhibited dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc), striatum, and ventral tegmental area and a reduction of hippocampal neurogenesis. CBD decreased dopaminergic neuronal loss in the SNpc, reduced the mortality rate and decreased neuroinflammation in 6-OHDA-lesioned rats. In parallel, CBD prevented memory impairments and attenuated despair-like behaviour that were induced by bilateral intranigral 6-OHDA lesions. Repeated treatment with CBD favoured the neuronal maturation of newborn neurons in the hippocampus in Parkinsonian rats. CONCLUSION: The present findings suggest a potential beneficial effect of CBD on non-motor symptoms induced by intra-nigral 6-OHDA infusion in rats.
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C-Jun-N-terminal-kinases (JNKs), members of the mitogen-activated-protein-kinase family, are significantly linked with neurological and neurodegenerative pathologies and cancer progression. However, JNKs serve key roles under physiological conditions, particularly within the central-nervous-system (CNS), where they are critical in governing neural proliferation and differentiation during both embryogenesis and adult stages. These processes control the development of CNS, avoiding neurodevelopment disorders. JNK are key to maintain the proper activity of neural-stem-cells (NSC) and neural-progenitors (NPC) that exist in adults, which keep the convenient brain plasticity and homeostasis. This review underscores how the interaction of JNK with upstream and downstream molecules acts as a regulatory mechanism to manage the self-renewal capacity and differentiation of NSC/NPC during CNS development and in adult neurogenic niches. Evidence suggests that JNK is reliant on non-canonical Wnt components, Fbw7-ubiquitin-ligase, and WDR62-scaffold-protein, regulating substrates such as transcription factors and cytoskeletal proteins. Therefore, understanding which pathways and molecules interact with JNK will bring knowledge on how JNK activation orchestrates neuronal processes that occur in CNS development and brain disorders.
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Diferenciação Celular , Células-Tronco Neurais , Neurogênese , Humanos , Animais , Diferenciação Celular/fisiologia , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/citologia , Neurogênese/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Neurônios/metabolismo , Neurônios/citologiaRESUMO
Introduction: Platelet-activating factor (PAF), PAF receptor (PAFR), and PAF- synthesis/degradation systems are involved in essential CNS processes such as neuroblast proliferation, differentiation, migration, and synaptic modulation. The retina is an important central nervous system (CNS) tissue for visual information processing. During retinal development, the balance between Retinal Progenitor Cell (RPC) proliferation and differentiation is crucial for proper cell determination and retinogenesis. Despite its importance in retinal development, the effects of PAFR deletion on RPC dynamics are still unknown. Methods: We compared PAFR knockout mice (PAFR-/-) retinal postnatal development proliferation and differentiation aspects with control animals. Electrophysiological responses were analyzed by electroretinography (ERG). Results and discussion: In this study, we demonstrate that PAFR-/- mice increased proliferation during postnatal retinogenesis and altered the expression of specific differentiation markers. The retinas of postnatal PAFR-/- animals decreased neuronal differentiation and synaptic transmission markers, leading to differential responses to light stimuli measured by ERG. Our findings suggest that PAFR signaling plays a critical role in regulating postnatal RPC cell differentiation dynamics during retinal development, cell organization, and neuronal circuitry formation.
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Background: Discovering biological markers is essential for understanding and treating mental disorders. Despite the limitations of current non-invasive methods, neural progenitor cells from the olfactory epithelium (hNPCs-OE) have been emphasized as potential biomarker sources. This study measured soluble factors in these cells in Major Depressive Disorder (MDD), Borderline Personality Disorder (BPD), and healthy controls (HC). Methods: We assessed thirty-five participants divided into MDD (n=14), BPD (n=14), and HC (n=7). MDD was assessed using the Hamilton Depression Rating Scale. BPD was evaluated using the DSM-5 criteria and the Structured Clinical Interview for Personality Disorders. We isolated hNPCs-OE, collected intracellular proteins and conditioned medium, and quantified markers and soluble factors, including Interleukin-6, interleukin-8, and others. Analysis was conducted using one-way ANOVA or Kruskal-Wallis test and linear regression. Results: We found that hNPCs-OE of MDD and BPD decreased Sox2 and laminin receptor-67 kDa levels. MASH-1 decreased in BPD, while tubulin beta-III decreased in MDD compared to controls and BPD. Also, we found significant differences in IL-6, IL-8, MCP-1, and thrombospondin-1 levels between controls and MDD, or BPD, but not between MDD and BPD. Conclusions: Altered protein markers are evident in the nhNPCs-OE in MDD and BPD patients. These cells also secrete higher concentrations of inflammatory cytokines than HC cells. The results suggest the potential utility of hNPCs-OE as an in vitro model for researching biological protein markers in psychiatric disorders. However, more extensive validation studies are needed to confirm their effectiveness and specificity in neuropsychiatric disorders.
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Obesity is a chronic disease caused by excessive fat accumulation that impacts the body and brain health. Insufficient leptin or leptin receptor (LepR) is involved in the disease pathogenesis. Leptin is involved with several neurological processes, and it has crucial developmental roles. We have previously demonstrated that leptin deficiency in early life leads to permanent developmental problems in young adult mice, including an imbalance in energy homeostasis, alterations in melanocortin and the reproductive system and a reduction in brain mass. Given that in humans, obesity has been associated with brain atrophy and cognitive impairment, it is important to determine the long-term consequences of early-life leptin deficiency on brain structure and memory function. Here, we demonstrate that leptin-deficient (LepOb) mice exhibit altered brain volume, decreased neurogenesis and memory impairment. Similar effects were observed in animals that do not express the LepR (LepRNull). Interestingly, restoring the expression of LepR in 10-week-old mice reverses brain atrophy, in addition to neurogenesis and memory impairments in older animals. Our findings indicate that leptin deficiency impairs brain development and memory, which are reversible by restoring leptin signalling in adulthood.
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Encéfalo , Leptina , Neurogênese , Receptores para Leptina , Animais , Receptores para Leptina/deficiência , Receptores para Leptina/genética , Receptores para Leptina/metabolismo , Camundongos , Encéfalo/metabolismo , Leptina/deficiência , Leptina/metabolismo , Neurogênese/fisiologia , Camundongos Knockout , Camundongos Endogâmicos C57BL , Masculino , Transtornos da Memória/metabolismo , Transtornos da Memória/genética , Atrofia/patologiaRESUMO
Pitt-Hopkins syndrome (PTHS) is a neurodevelopmental disorder caused by haploinsufficiency of transcription factor 4 (TCF4). In this work, we focused on the cerebral cortex and investigated in detail the progenitor cell dynamics and the outcome of neurogenesis in a PTHS mouse model. Labeling and quantification of progenitors and newly generated neurons at various time points during embryonic development revealed alterations affecting the dynamic of cortical progenitors since the earliest stages of cortex formation in PTHS mice. Consequently, establishment of neuronal populations and layering of the cortex were found to be altered in heterozygotes subjects at birth. Interestingly, defective layering process of pyramidal neurons was partially rescued by reintroducing TCF4 expression using focal in utero electroporation in the cerebral cortex. Coincidentally with a defective dorsal neurogenesis, we found that ventral generation of interneurons was also defective in this model, which may lead to an excitation/inhibition imbalance in PTHS. Overall, sex-dependent differences were detected with more marked effects evidenced in males compared with females. All of this contributes to expand our understanding of PTHS, paralleling the advances of research in autism spectrum disorder and further validating the PTHS mouse model as an important tool to advance preclinical studies.
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Córtex Cerebral , Modelos Animais de Doenças , Hiperventilação , Deficiência Intelectual , Neurogênese , Fator de Transcrição 4 , Animais , Fator de Transcrição 4/metabolismo , Fator de Transcrição 4/genética , Feminino , Masculino , Camundongos , Hiperventilação/metabolismo , Hiperventilação/genética , Hiperventilação/patologia , Deficiência Intelectual/genética , Deficiência Intelectual/patologia , Deficiência Intelectual/metabolismo , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Fácies , Caracteres Sexuais , Interneurônios/metabolismo , Interneurônios/patologia , Células Piramidais/metabolismo , Células Piramidais/patologia , HaploinsuficiênciaRESUMO
Parkinson's disease (PD) is a complex neurodegenerative disorder characterized by motor and non-motor symptoms. Motor symptoms include bradykinesia, resting tremors, muscular rigidity, and postural instability, while non-motor symptoms include cognitive impairments, mood disturbances, sleep disturbances, autonomic dysfunction, and sensory abnormalities. Some of these symptoms may be influenced by the proper hippocampus functioning, including adult neurogenesis. Doublecortin (DCX) is a microtubule-associated protein that plays a pivotal role in the development and differentiation of migrating neurons. This study utilized postmortem human brain tissue of PD and age-matched control individuals to investigate DCX expression in the context of adult hippocampal neurogenesis. Our findings demonstrate a significant reduction in the number of DCX-expressing cells within the subgranular zone (SGZ), as well as a decrease in the nuclear area of these DCX-positive cells in postmortem brain tissue obtained from PD cases, suggesting an impairment in the adult hippocampal neurogenesis. Additionally, we found that the nuclear area of DCX-positive cells correlates with pH levels. In summary, we provide evidence supporting that the process of hippocampal adult neurogenesis is likely to be compromised in PD patients before cognitive dysfunction, shedding light on potential mechanisms contributing to the neuropsychiatric symptoms observed in affected individuals. Understanding these mechanisms may offer novel insights into the pathophysiology of PD and possible therapeutic avenues.