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Resumen La obesidad es considerada actualmente como un problema de salud pública global y se caracteriza por la hipertrofia e hiperplasia del tejido adiposo debido a la ingesta hipercalórica y la falta de actividad física, disfunción metabólica, inflamación sistémica crónica de bajo grado y gradualmente neuroinflamación hipotalámica. El tejido adiposo actúa como un órgano endocrino secretando adipocinas y citocinas que actúan como reguladores del metabolismo. Sin embargo, la presencia de niveles elevados de ácidos grasos libres y de moléculas inflamatorias derivadas de los adipocitos, pueden alterar la respuesta inmunitaria sistémica, generando inflamación crónica, comprometiendo la integridad de la barrera hematoencefálica y estimulando la respuesta de la glía, especialmente en regiones específicas del hipotálamo, centro de regulación de la homeostasis energética. Las células gliales hipotalámicas son importantes en la transmisión de señales inflamatorias relacionadas con la dieta, pueden modular la actividad neuronal, responder a las señales inmunológicas periféricas e iniciar una respuesta inflamatoria local y gliosis. Esta revisión se enfoca en la descripción general de la disfunción metabólica asociada a la obesidad y su participación en la alteración de la regulación hipotalámica, provocando neuroinflamación y modificaciones en la conducta alimentaria.
Abstract Nowadays, obesity is considered a worldwide rising health problem and is characterized by adipose tissue hypertrophy and hyperplasia due to hypercaloric intake and lack of physical activity, promoting the development of metabolic dysfunction, low-grade systemic chronic inflammation, and gradually hypothalamic neuroinflammation. Adipose tissue acts as an endocrine organ secreting adipokines and cytokines around peripheral organs, functioning as a master metabolism regulator. However, high levels of adipocyte-derived free fatty acids and inflammatory molecules promote impairments in systemic immune response, generate chronic inflammation, disrupt the blood-brain barrier, and stimulate glia, specifically in some hypothalamic regions, the master regulators of energetic homeostasis. Hypothalamic glial cells are essential in diet-related inflammatory signals transmission and can modulate neuronal activity, also respond to peripheral inflammatory signals and begin local inflammatory response and gliosis. This review aims to analyze obesity-related metabolic dysfunction and how it participates in the hypothalamic regulation impairments due to neuroinflammation and impairment in food intake behavior.
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Abstract Astrocytes are the most abundant cell subtypes in the central nervous system. Previous studies believed that astrocytes are supporting cells in the brain, which only provide nutrients for neurons. However, recent studies have found that astrocytes have more crucial and complex functions in the brain, such as neurogenesis, phagocytosis, and ischemic tolerance. After an ischemic stroke, the activated astrocytes can exert neuroprotective or neurotoxic effects through a variety of pathways. In this review, we will discuss the neuroprotective mechanisms of astrocytes in cerebral ischemia, and mainly focus on reactive astrocytosis or glial scar, neurogenesis, phagocytosis, and cerebral ischemic tolerance, for providing new strategies for the clinical treatment of stroke.
Resumo Os astrócitos são os subtipos de células mais abundantes no sistema nervoso central. Estudos anteriores acreditavam que os astrócitos são células de suporte no cérebro, que apenas fornecem nutrientes para os neurônios. No entanto, estudos recentes descobriram que os astrócitos têm funções mais cruciais e complexas no cérebro, como neurogênese, fagocitose e tolerância isquêmica. Após um acidente vascular cerebral isquêmico, os astrócitos ativados podem exercer efeitos neuroprotetores ou neurotóxicos através de uma variedade de vias. Nesta revisão, discutiremos os mecanismos neuroprotetores dos astrócitos na isquemia cerebral, e focaremos principalmente na astrocitose reativa ou cicatriz glial, neurogênese, fagocitose e tolerância isquêmica cerebral, para fornecer novas estratégias para o tratamento clínico do acidente vascular cerebral.
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Introducción: El sistema glinfático comprende el conjunto de rutas perivasculares tanto arteriales como venosas que se encuentran en estrecha asociación con células astrogliales y que permiten la interacción entre el líquido cefalorraquídeo (LCR) y el líquido intersticial cerebral (LIC), para llevar a cabo procesos como la depuración de los metabolitos de desecho celular, o la distribución de nutrientes, así como contribuir al metabolismo cerebral local, la transmisión de volumen y la señalización paracrina cerebral. Contenidos: Este artículo busca profundizar en los conceptos anatómicos y fisiológicos, hasta el momento descritos, sobre este sistema macroscópico de transporte. Se realiza una búsqueda bibliográfica de revisiones y estudios experimentales sobre la anatomía, la fisiología y las implicaciones fisiopatológicas del sistema glinfático. Conclusiones: La identificación anatómica y funcional del sistema glinfático ha ampliado el conocimiento sobre la regulación del metabolismo cerebral en cuanto a distribución de nutrientes y cascadas de señalización celular. Al establecer una interacción entre el espacio subaracnoideo subyacente y el espacio intersticial cerebral, el sistema glinfático surge como uno de los mecanismos protagonistas de la homeostasis cerebral. La disfunción de esta vía hace parte de los mecanismos fisiopatológicos de múltiples trastornos neurológicos, ya sea por la acumulación de macromoléculas, como ocurre en la enfermedad de Alzheimer, o por la reducción del drenaje de sustancias químicas y citocinas proinflamatorias en patologías como la migraña o el trauma craneoencefálico.
Introduction: The glympathic system comprises the set of perivascular routes, arterials or venous, that are found in close relationship with astroglial cells and allow interaction between the cerebrospinal fluid (CSF) and the interstitial brain fluid (ISF), to carry processes like cell-wasting metabolites depuration, nutrients distribution, as well as make a contribution in the local brain metabolism, volumen transmition and brain paracrine signaling. Contents: This article seeks to deepen in the anatomical and physiological concepts, so far described, about this macroscopic transport system. A bibliographic search of reviews and experimental studies on the anatomy, physiology and pathophysiological implications of the glymphatic system is carried out. Conclusions: Anatomical and functional identification of glympathic system has broaden the knowledge about regulation of brain metabolism on the nutrients distribution and cell signaling cascades. When setting an interaction between the subarachnoid space and the brain interstitial space, the glymphatic system arise as one of the leading mechanisms of brain homeostasis. Disfunction of this pathway makes part of the patophysiological mechanisms of multiple neurological disease, either be by collection of macromolecules as in Alzheimer's disease, or by the reduction of inflammatory cytokines and chemical substances drainage as in migraine or traumatic brain injury (TBI).
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Objective:To explore the process of regression of the hyaloid vessels and development of retinal vessels in C57BL/6J mice and the relationship between them.Methods:Seventy-five healthy SPF C57BL/6J mice on postnatal day 1 (P1) were selected and divided into control group (65 mice) and oxygen-induced retinopathy (OIR) model group (10 mice) by the random number table method.No treatment was given to control group.Mice in OIR model group were continuously fed in (75±3)% oxygen for 5 days from P7 and in normoxic condition for 5 days from P12.In control group, 5 mice were randomly selected and killed from P1 to P12 and P17, and the eyeballs were collected.In OIR model group, 5 mice were randomly selected and killed on P12 and P17, and the eyeballs were collected.The number of hyaloid arteries (HA), vasa hyaloidea propria (VHP), and tunica vasculosa lentis (TVL) of mice at different time was observed with a microscope.Another 5 adult mice aged 15 months old were selected to detect the vitreous vasculature using optical coherence tomography.The relationship between retinal astrocytes and retinal vascular development, VHP was observed by immunofluorescence staining.This study was approved by the Ethics Committee of Nankai Hospital (No.NKYY-DWLL-2021-070). The use and care of experimental animals followed the Regulations for the Administration of Affairs Concerning Experimental Animals and the ARVO statement.Results:In control group, HA did not degenerate rapidly during eyeball development, which still presented even 15 months after birth.The number of VHP reduced rapidly from P4 to P8, and tended to be stable at 2.33±1.32 on P10 and 1.80±0.92 on P17.The number of TVL reduced rapidly from P5 to P9, reduced to 2.30±1.42 on P10, with most of the TVL blood vessels being transparent without blood supply, and decreased to 0.30±0.48 on P17.Under the guidance of astrocytes, the retinal vessels of mice grew from the optic disc to the peripheral retina from P1 to P8, forming the primary retinal vascular layer.During the development of retinal superficial vessels, VHP showed synchronous regression and the decreased density and thinner diameter in the area covered by retinal vessels.VHP detached from the retina when retinal vessels developed to the peripheral retina, and there was no structural overlap between astrocytes and VHP.In OIR model group, the number of VHP increased from 2.14±0.90 on P12 to 4.60±1.35 on P17 and the number of TVL increased from 2.90±1.55 on P12 to 5.80±1.75 on P17, showing statistically significant differences ( t=4.188, P<0.001; t=4.668, P<0.001). There was no significant difference in the number of VHP and TVL between the two groups on P12 ( t=0.429, P=0.232; t=1.116, P=0.134). The number of VHP and TVL were significantly larger in OIR model group than in control group on P17 ( t=5.422, 9.574; both at P<0.001). Conclusions:In the vitreous vascular system of mice, the regression of VHP and TVL tends to be stable 10 days after birth, and the regression of HA was not obvious.The normal regression of vitreous vessels in mice depends on the normal development of retinal vessels and astrocytes.Retinal hypoxia delays vitreous vascular regression.
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ObjectiveTo investigate the mechanism of Dihuang Yinzi in improving astrocyte injury and protecting synaptic structure and function in the brain of Alzheimer's disease （AD） mice. MethodForty male APP/PS1 transgenic mice aged four months were randomly divided into a model group and a model + Dihuang Yinzi （0.25 g·kg-1） group， with 20 mice in each group. Forty C57BL/6J mice with the same background and same age were randomly divided into a control group and a control + Dihuang Yinzi （0.25 g·kg-1） group， with 20 mice in each group. The mice in the control + Dihuang Yinzi group and the model + Dihuang Yinzi group were administered with Dihuang Yinzi by gavage， and those in the control group and the model group received an equal volume of sterilized normal saline， once a day for 150 days. The learning and memory ability of mice was tested by the light-dark box test and Y-maze spontaneous alternation test. The content of glutamate （Glu） and glutamine （Gln） was measured by liquid chromatography-tandem mass spectrometry （LC-MS）. Long-term potentiation （LTP） assay was used to detect synaptic plasticity in brain tissues. The protein expression levels of excitatory amino acid transporter 2 （EAAT2）， postsynaptic density protein95 （PSD95）， and synaptophysin （SYN） in brain tissues were measured by Western blot. Immunofluorescence was used to assess the localization and expression of EAAT2. Colorimetry was performed to detect Na+-K+ ATPase activity in mouse brain tissues. ResultAs compared with the control group， the model group showed shortened residence latency （P<0.01）， increased number of errors （P<0.01） in the light-dark box test， reduced spontaneous alternation behaviors （P<0.01）， no significant difference in the total number of arm entries in the Y-maze spontaneous alternation test， down-regulated expression of EAAT2， PSD95， and SYN （P<0.01）， blunted activity of Na+-K+ ATPase （P<0.01）， up-regulated Glu level （P<0.01）， down-regulated Gln level （P<0.01）， and reduced relative population spike （PS） amplitude and the slope of excitatory postsynaptic potential （EPSP） （P<0.05， P<0.01）， while the above experimental indexes were not significantly different in the control + Dihuang Yinzi group. Compared with the model group， the model + Dihuang Yinzi group displayed prolonged residence latency （P<0.05）， decreased number of errors （P<0.01） in the light-dark box test， increased spontaneous alternation behaviors （P<0.01）， no significant difference in the total number of arm entries in the Y-maze spontaneous alternation test， up-regulated expression of EAAT2， PSD95， and SYN （P<0.01）， potentiated activity of Na+-K+ ATPase （P<0.01）， reduced Glu level （P<0.01）， up-regulated Gln level （P<0.01）， and increased PS amplitude and EPSP slope （P<0.01）. ConclusionDihuang Yinzi can improve cognitive dysfunction in AD mice by protecting astrocytes， increasing Glu uptake to reduce its abnormal accumulation， and protecting synaptic structure and function.
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ObjectiveTo explore the mechanism of Dihuang Yinzi （DHYZ）in improving astrocyte injury in the brain and regulating energy metabolism and autophagy disorder in Alzheimer's disease （AD） model mice. MethodForty male APP/PS1 transgenic mice aged four months were randomly divided into a model group and a model + DHYZ group （2.5 g·kg-1）， with 20 mice in each group. Forty C57BL/6J mice with the same background and same age were randomly divided into a control group and a control + DHYZ group （2.5 g·kg-1）， with 20 mice in each group. The mice in the control group and the model group were administered with an equal volume of sterilized normal saline by gavage， once a day for 150 days. Novel object recognition test and step-down test were performed to evaluate the learning and memory ability of mice. The expression of glial fibrillary acidic protein （GFAP） in astrocytes was detected by immunofluorescence and Western blot. High-performance liquid chromatography （HPLC） was used to detect adenosine triphosphate （ATP）， adenosine diphosphate （ADP）， and adenosine monophosphate （AMP） in brain tissues of mice， and the data obtained were used to calculate energy charge （EC） levels. The phosphorylation levels of liver kinase B1 （LKB1）， adenosine 5′-monophosphate （AMP）-activated protein kinase （AMPK）， UNC-51-like kinase 1 （ULK1）， and mammalian target of rapamycin （mTOR） and the expression levels of autophagy-related proteins Beclin-1， microtuble-associated protein 1 light chain 3 （LC3）-Ⅱ/LC3-Ⅰ， and p62 in mouse brain were measured by Western blot. ResultCompared with the control group， the model group showed decreased novel object recognition index， shortened retention latency， increased error times in the step-down test， up-regulated protein expression of GFAP， decreased content of ATP， ADP， and EC in brain tissues， elevated AMP ， increased levels of p-AMPK， p-LKB1， and p-mTOR， and protein expression of p62 ， and down-regulated p-ULK1 level and protein expression of Beclin-1 and LC3-Ⅱ/LC3-Ⅰ（P<0.01）， while the above experimental indexes were not significantly different in the control + DHYZ group. Compared with the model group， the model + DHYZ group showed increased novel object recognition index（P<0.05）， prolonged retention latency（P<0.01）， decreased error times（P<0.01） in the step-down test， reduced protein expression of GFAP（P<0.05）， increased content of ATP， ADP， and EC in brain tissues （P<0.05， P<0.01）， decreased AMP content（P<0.05）， reduced p-AMPK， p-LKB1， and p-mTOR levels and protein expression of p62， and up-regulated p-ULK1 level and protein expression of Beclin-1 and LC3-Ⅱ/LC3-Ⅰ（P<0.01）. ConclusionBy protecting astrocytes， DHYZ can improve energy metabolism and autophagy disorder in AD mice to improve the learning and memory ability of model mice.
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ObjectiveTo explore the mechanism of Dihuang Yinzi in improving astrocyte injury and glycolysis in Alzheimer's disease （AD） mice via regulating the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway， thereby improving the cognitive function of AD mice. MethodForty male APP/PS1 transgenic mice aged four months were randomly divided into a model group and a model + Dihuang Yinzi （0.25 g·kg-1） group， with 20 mice in each group. Forty C57BL/6J mice with the same background and same age were randomly divided into a control group and a control + Dihuang Yinzi （0.25 g·kg-1） group， with 20 mice in each group. The mice in the control + Dihuang Yinzi group and the model + Dihuang Yinzi group were administered with Dihuang Yinzi by gavage， and those in the control group and the model group received an equal volume of sterilized normal saline， once a day for 150 days. Morris water maze test was performed to test the ability of navigation and space exploration of mice. The protein expression of p-PI3K， PI3K， p-Akt， Akt， phosphofructokinase-1 （PFK-1）， and aldehyde dehydrogenase 3 family member B2 （ALDH3B2） in mouse brain tissues was measured by Western blot. An immunofluorescence assay was performed to detect astrocyte morphology and the expression level of ALDH3B2. ResultAs compared with the control group， the model group showed prolonged escape latency during the 2nd to 5th days of the location-based navigation （P<0.05， P<0.01）， reduced number of times crossing the target area of the platform， shortened residence time in the target quadrant （P<0.05， P<0.01）， prolonged residence time in the opposite quadrant （P<0.05）， increased surface area of the cell body and total length of cell protrusions of astrocytes （P<0.05， P<0.01）， and down-regulated protein expression of p-PI3K， p-Akt， ALDH3B2， and PFK-1 （P<0.01）， while the above experimental indexes were not significantly different in the control + Dihuang Yinzi group. Compared with the model group， the model + Dihuang Yinzi group showed shortened escape latency of APP/PS1 mice during the 2nd to 5th days of the location-based navigation （P<0.05， P<0.01）， increased number of times crossing the platform， prolonged target quadrant residence time （P<0.05， P<0.01）， shortened residence time in the opposite quadrant （P<0.05）， reduced surface area of the cell body and total length of cell protrusions of astrocytes （P<0.05）， and up-regulated protein expression of p-PI3K， p-Akt， ALDH3B2， and PFK-1 （P<0.01）. ConclusionDihuang Yinzi can improve the learning and memory ability of AD mice by activating the PI3K/Akt signaling pathway and up-regulating the protein expression of PFK-1 and ALDH3B2 to protect against astrocyte injury in brain tissues and improve glycolysis.
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ObjectiveTo investigate the mechanism of Yiqi Huoxue Tongluo prescription （YHTP） in the treatment of diabetic neuropathic pain （DNP）. MethodNinety SPF-grade SD male rats were randomized into blank， model， low- （2.25 g·kg-1）， medium- （4.5 g·kg-1）， and high-dose （9 g·kg-1） YHTP， and mecobalamin （0.175 mg·kg-1） groups. Except those in the blank group， the rats in the remaining 5 groups were fed with a high-fat and high-glucose diet and subjected to intraperitoneal injection of low-dose （35 mg·kg-1） streptozotocin （STZ） to establish the model of DNP. The sciatic nerve conduction velocity in DNP rats was measured by the neurophysiological method， and the levels of interleukin-6 （IL-6）， IL-1β， and tumor necrosis factor-α （TNF-α） were measured by enzyme-linked immunosorbent assay （ELISA）. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was employed to measure the mRNA levels of glial fibrillary acidic protein （GFAP） and extracellular signal-regulated kinase （ERK） in the spinal cord. Western blot was employed to measure the protein levels of GFAP and phosphorylated ERK （p-ERK）， and immunofluorescence staining to measure the fluorescence intensity of GFAP and p-ERK in the spinal cord. In the cell experiments， 100 mmol·L-1 high glucose was used to induce the activation of astrocytes （CTX-TNA2） for the modeling of nerve cell injury. The cells were randomized into the normal， model， drug-containing serum （10% YQHT）， inhibitor ［10 mol·L-1 corynoxeine （COR）］， drug-containing serum + inhibitor （10% YHTP + 10 mol·L-1 COR） groups. The levels of pro-inflammatory factors （TNF-α and IL-1β） and the anti-inflammatory factor IL-10 in CTX-TNA2 cells were determined by ELISA， and the protein levels of GFAP and p-ERK in CTX-TNA2 cells by Western blot. ResultThe animal experiments showed that compared with the blank group， the model group presented reduced mechanical withdrawal threshold （MWT）， thermal work limit （TWL）， and nerve conduction velocity， elevated levels of fasting blood glucose， IL-1β， TNF-α， and IL-6， and up-regulated protein levels of GFAP and p-ERK， and mRNA levels of ERK1， ERK2， GFAP （P<0.01）. Compared with model group， YHTP increased the MWT， TWL， and sciatic nerve conduction velocity （P<0.01）， lowered the levels of IL-1β， TNF-α， and IL-6 （P<0.01）， and down-regulated the protein levels of GFAP and p-ERK， and mRNA levels of ERK1， ERK2， GFAP in the spinal cord （P<0.05， P<0.01）. The cell experiments showed that compared with the blank group， the model group had decreased survival rate， elevated levels of pro-inflammatory factors， and up-regulated protein levels of ERK and GFAP （P<0.01）. Compared with the model group， the YHTP-containing serum lowered the levels of IL-1β and TNF-α （P<0.05， P<0.01）， elevated the level of IL-10 （P<0.01）， and down-regulated the protein levels of ERK and GFAP （P<0.01）. ConclusionYHTP may inhibit the activation of astrocytes by inhibiting the ERK signaling pathway to reduce inflammation and thus relieve DNP.
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Objective:To investigate the role and underlying mechanisms of inhibiting high mobility group box-1 (HMGB1) in the expression of matrix metalloproteinase-9 (MMP-9) in spinal cord astrocytes (AS) in rats after spinal cord injury (SCI).Methods:After an SCI model was established in Sprague-Dawley (SD) rats using a modified Allen's Weight-Dropping method and ethyl pyruvate (EP) or glycyrrhizin (GL) was used to inhibit the effect of HMGB1, the rats were divided into a sham group, an SCI group, an SCI+EP (50 mg/kg) group, and an SCI+GL (100 mg/kg) group. The expression levels of glial fibrillary acid protein (GFAP) and MMP-9 in spinal cord AS were observed. After the spinal cord AS in SD rats was cultured and incubated by the oxygen-glucose deprivation/reoxygenation (OGD/R) procedure, the expression of MMP-9 protein was detected at 6 h/R 6 h, 12 h, 24 h, and 48 h after OGD. The time point with the highest expression was chosen in the subsequent experiments as an OGD/R group. HMGB1 was inhibited by HMGB1 shRNA or EP to observe the effect of HMGB1 on the expression of MMP-9 protein in AS treated with OGD/R. Then, toll-like receptor 4 (TLR4) inhibitor, TIR-domain-containing adaptor inducing interferon- β (TRIF) inhibitor, and nuclear factor-kappa B (NF- κB) inhibitor were used to investigate the effects of TLR4/TRIF/NF- κB signaling pathway during the regulation of HMGB1 on MMP-9 in vitro. Results:Western blot showed that the expression of MMP-9 protein in the spinal cord was significantly increased in rats at 1 d after SCI, and the expression of MMP-9 protein in the SCI+EP group and the SCI+GL group was significantly lower than that in the SCI group ( P<0.001). Immunofluorescence showed that GFAP and MMP-9 proteins were co-localized in the spinal cord after SCI, and the expression of GFAP and MMP-9 proteins in the SCI+EP and SCI+GL groups was significantly lower than that in the SCI group ( P<0.05). Since the expression of MMP-9 protein in the spinal cord AS cultured in vitro was significantly higher in the OGD 6h/R 12h group than that in the normal group and the OGD 6h/R 6h, 24, and 48 h groups, the OGD 6h/R 12h was taken as the OGD/R group. The MMP-9 protein expression in AS in the OGD/R+HMGB1 shRNA group and the OGD/R+EP group was significantly lower than that in the OGD/R group ( P<0.001). In the cultured AS, moreover, inhibiting TLR4, TRIF, and NF- κB reduced MMP-9 protein expression after OGD 6 h/R 12 h when compared with that in the OGD/R group ( P<0.001). Conclusions:HMGB1 inhibition may result in a reduction in MMP-9 expression both in the spinal cord AS in SCI rats and in AS after OGD/R treatment in vitro. HMGB1 may regulate MMP-9 protein expression in AS after OGD/R treatment via the TLR4/TRIF/NF- κB signal pathway.
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Objective:To investigate the effect of aucubin on behaviors and excessive activation of astrocytic in attention deficit/hyperactivity disorder (ADHD) model mice.Methods:Twelve wild-type C57BL/6 pregnant mice (female, clean grade) were intraperitoneally administered with esketamine (15 mg/kg) to establish an ADHD model in offspring mice. The offspring mice were divided into control+ saline group, control+ aucubin group, Ketamine+ saline group and Ketamine+ aucubin group according to the nest matching principle with 15 in each group.At 14 days after birth, mice in the control+ aucubin group and Ketamine+ aucubin group were administered with aucubin (5 mg/kg, once a day) by gavage for 5 days. Mice in control+ saline group and Ketamine+ saline group were administered with equal volume of 0.9% sodium chloride solution. The offspring mice were housed with their mothers in the same cage until 21 days after birth. Twenty-one days after birth, the offspring mice were evaluated by open field test and elevated plus maze tests. Immunofluorescence assay was used to detect the expression of glutamate decarboxylase 2 (GAD2), γ- aminobutyric acid (GABA) and glial fibrillary acidic protein (GFAP) in the amygdala. The morphological changes of astrocytes were quantitatively analyzed by Sholl analysis. GraphPad Prim 9.0.1 software was used for statistical analysis. The comparison of multiple groups was conducted by one-way ANOVA or Kruskal-Wallis test.Results:(1)The results of behavioral experiments showed that the total distance traveled in the open field test and the residence time in open arm of the elevated plus maze were statistically significant ( F=236.90, H=39.92, both P<0.001). The total distance ((7 044±249)mm, (22 891±2 175)mm, P<0.05) and the residence time in open arm(12.69(9.86, 17.24)s, 2.72(0.57, 3.87)s, P<0.05) of mice in Ketamine+ saline group were both higher than those in control+ saline group.The total distance((22 891±2 175)mm, (8 252±839)mm, P<0.05) and the the residence time in open arm(5.45(1.13, 10.99)s, 12.69(9.86, 17.24)s, P<0.05) of Ketamine+ aucubin group were both lower than those of Ketamine+ saline group.(2)The immunofluorescence results showed that the levels of GAD2, GABA and GFAP intensity in amygdala of mice in the four groups were statistically significant ( F=145.50, 50.08, 53.83, all P<0.05). Compared with control+ saline group, the fluorescence intensities of GAD2 ((100.00±9.60)%, (24.86±4.14)%, P<0.05) and GABA ((100.00±16.84))%, (25.48±5.70)%, P<0.05) of Ketamine+ saline group were down-regulated, and the GFAP((100.00±18.02)%, (223.80±25.85)%, P<0.05) was up-regulated. Compared with Ketamine+ saline group, the fluorescence intensities of GAD2 ((24.86±4.14)%, (56.08±6.55)%, P<0.05) and GABA((25.48±5.70)%, (52.59±15.74)%, P<0.05) in Ketamine+ aucubin group were up-regulated, but the fluorescence intensity of GFAP ((223.80±25.85)%, (157.10±22.10)%, P<0.05) was down-regulated.(3)Sholl analysis indicated that the number of the intersections between the astrocyte processes or the branches of astrocyte processes was statistically significant in the 4 groups ( F=12.47, P<0.05). Compared with control+ saline group, the number of the intersections in Ketamine+ saline group((2.07±0.48), (1.67±0.72), P<0.05) increased. While the number of the intersections in Ketamine+ aucubin group was lower than that of Ketamine+ saline group ((1.20±0.78), (2.07±0.48), P<0.05). Conclusion:Aucubin administration can alleviate ADHD-like behaviors in offspring mice, and the mechanism may be associated with the inhibition of excessive astrocytic activation.
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Alanine-serine-cysteine transporter 2 (ASCT2) is reported to participate in the progression of tumors and metabolic diseases. It is also considered to play a crucial role in the glutamate-glutamine shuttle of neuroglial network. However, it remains unclear the involvement of ASCT2 in neurological diseases such as Parkinson's disease (PD). In this study, we demonstrated that high expression of ASCT2 in the plasma samples of PD patients and the midbrain of MPTP mouse models is positively correlated with dyskinesia. We further illustrated that ASCT2 expressed in astrocytes rather than neurons significantly upregulated in response to either MPP+ or LPS/ATP challenge. Genetic ablation of astrocytic ASCT2 alleviated the neuroinflammation and rescued dopaminergic (DA) neuron damage in PD models in vitro and in vivo. Notably, the binding of ASCT2 to NLRP3 aggravates astrocytic inflammasome-triggered neuroinflammation. Then a panel of 2513 FDA-approved drugs were performed via virtual molecular screening based on the target ASCT2 and we succeed in getting the drug talniflumate. It is validated talniflumate impedes astrocytic inflammation and prevents degeneration of DA neurons in PD models. Collectively, these findings reveal the role of astrocytic ASCT2 in the pathogenesis of PD, broaden the therapeutic strategy and provide a promising candidate drug for PD treatment.
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For decades, memory research has centered on the role of neurons, which do not function in isolation. However, astrocytes play important roles in regulating neuronal recruitment and function at the local and network levels, forming the basis for information processing as well as memory formation and storage. In this review, we discuss the role of astrocytes in memory functions and their cellular underpinnings at multiple time points. We summarize important breakthroughs and controversies in the field as well as potential avenues to further illuminate the role of astrocytes in memory processes.
Subject(s)
Astrocytes , Neuronal Plasticity/physiology , Memory/physiology , Neurons/physiology , Cognition/physiologyABSTRACT
Non-coding RNAs (ncRNAs) are a class of functional RNAs that play critical roles in different diseases. NcRNAs include microRNAs, long ncRNAs, and circular RNAs. They are highly expressed in the brain and are involved in the regulation of physiological and pathophysiological processes of central nervous system (CNS) diseases. Mounting evidence indicates that ncRNAs play key roles in CNS diseases. Further elucidating the mechanisms of ncRNA underlying the process of regulating glial function that may lead to the identification of novel therapeutic targets for CNS diseases.
Subject(s)
Humans , RNA, Untranslated/genetics , MicroRNAs/genetics , RNA, Long Noncoding/genetics , RNA, Circular , Central Nervous System Diseases/geneticsABSTRACT
Glial cells in the central nervous system (CNS) are composed of oligodendrocytes, astrocytes and microglia. They contribute more than half of the total cells of the CNS, and are essential for neural development and functioning. Studies on the fate specification, differentiation, and functional diversification of glial cells mainly rely on the proper use of cell- or stage-specific molecular markers. However, as cellular markers often exhibit different specificity and sensitivity, careful consideration must be given prior to their application to avoid possible confusion. Here, we provide an updated overview of a list of well-established immunological markers for the labeling of central glia, and discuss the cell-type specificity and stage dependency of their expression.
Subject(s)
Neuroglia/metabolism , Central Nervous System , Oligodendroglia/metabolism , Astrocytes/metabolism , MicrogliaABSTRACT
Objective:To study the efficacy of low-intensity focused ultrasound (LIFU) on neuropathic pain (NP) in mice, and its effect on the activation of astrocytes and the expression of pro-inflammatory cytokines were discussed.Methods:Thirty-six male C57BL/6J mice were randomly divided into three groups: sham operation (Sham) group and chroinc constriction injury (CCI) model group and treatment (CCI+ LIFU) group, 12 mice in each group.NP model was established by CCI on the sciatic nerve. The group of CCI+ LIFU received LIFU treatment for the anterior cingulate cortex (ACC) on the 7th day after surgery, the mechanical withdrawal threshold (MWT) on the affected side of mice was measured at preoperation 3, 6, 12, 18, 24, and 27 days after operation, respectively, H&E staining was used to observe pathological morphological changes in the ACC region, the expression levels of ACC region AQP4 and GFAP protein were detected by Western Blot and immunofluorescence, and the expression levels of ACC region pro-inflammatory cytokines IL-1β and TNF-α were detected by enzyme-linked immunosorption assay.Results:Compared with Sham group, MWT in the CCI group decreased from the 3rd day until the 27th day after surgery( P<0.05); Compared with the CCI group, the MWT in the CCI+ LIFU group increased on the 24th day after surgery, and was significantly higher than that of the CCI group on the 24th and 27th day after surgery ( P<0.05); LIFU stimulation did not produce significant pathological changes in the ACC region; Western Blot and immunofluorescence showed that AQP4 and GFAP protein expression in the ACC region were upregulated ( P<0.05) after peripheral nerve injury, while AQP4 and GFAP protein expression was downregulated after LIFU treatment ( P<0.05); Enzyme-linked immunosorbents showed that the expression of pro-inflammatory cytokines IL-1β and TNF-α in the region of ACC was upregulated ( P<0.05) after peripheral nerve injury, while the expression of IL-1β and TNF-α was downregulated after LIFU treatment ( P<0.05). Conclusions:LIFU can effectively relieve mechanical pain sensitivity symptoms in mice induced by CCI, possibly by inhibiting activation of astrocytes and neuro-inflammatory responses.
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Spinal cord injury can be divided into primary and secondary injury. As an important process of spinal cord injury, secondary injury can be classified into acute phase, subacute phase and chronic phase according to the time and progression of the injury. Oxidative stress reaction, inflammatory reaction, tissue edema, scar formation and other pathological changes appear subsequently during the process. In the central nervous system, the astrocyte is one of the most widely distributed cell that has different shapes at different stages and plays a complex role such as anti-inflammatory or pro-inflammatory action and neuroprotective or anti-neurorestorative effect after spinal cord injury. The astrocyte has been a research focus in the field of spinal cord injury. The authors review the role and research progress of astrocyte in oxidative stress response, excitotoxicity, inflammatory response, tissue edema, scar formation, axonal regeneration and cell transformation in spinal cord injury based on the pathological changes of secondary injury, in order to provide new ideas to the related research of spinal cord injury.
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Objective:To explore the effect of social isolation (SI) on cognitive function and the phenotypic transition of hippocampal astrocytes in mice.Methods:Twenty male C57BL/6 mice aged 3-4 weeks were randomly divided into normal group house (GH group) and social isolation group (SI Group). The mice in SI group were fed one per cage for 8 weeks to establish a social isolation model, and the mice in GH group were fed five per cage. The cognitive function of mice was detected by the novel object recognition test and novel location recognition test. The expression of astrocyte marker glial fibrillary acidic protein (GFAP) was detected by immunohistochemistry, RT-PCR and Western blot.The astrocyte morphology change was quantitatively analyzed by Sholl Analysis.The expression of the hippocampal A1-A2 astrocytes markers proteasome subunit beta 8(PSMB8) and a member of the S100 family of Ca 2+ -binding proteins (S100A10) were determined by RT-PCR and Western blot. Statistical analysis was performed using GraphPad Prism 6.0 software, and t-test was used for comparison between two groups. Results:The results of cognitive function showed that the exploration index of novel object ((-5.54±3.30)%, (33.42±7.14)%; t=4.680, P=0.001) and the exploration index of novel location((-7.96±4.81)%, (23.55±8.20)%; t=3.670, P=0.008) in SI group were both lower than those in GH group.Immunohistochemical results showed that the number of GFAP positive cells in hippocampus of SI group was significantly lower than that of GH group((369.90±42.97), (544.90±57.64); t=2.480, P=0.023). The results of Sholl analysis showed that the protuberance of hippocampal astrocytes in SI Group retracted.There were significant differences in the number of intersections between the two groups at 6, 8, 10, 12, 14 and 16 μm away from astrocyte cell body(all P<0.05). Western blot showed that the expression of GFAP protein in SI group was lower than that in GH group((0.85±0.05), (1.03±0.06); t=2.527, P=0.028). The results of PCR showed that the expression of GFAP mRNA in SI group was lower than that in GH group ((0.83±0.05), (1.00±0.03); t=2.970, P=0.018). The expression of A1 phenotypic marker PSMB8 mRNA ((1.58±0.17), (1.00±0.06); t=2.931, P=0.011) and A2 phenotypic marker S100A10 mRNA ((1.52±0.14), (1.00±0.07); t=3.121, P=0.007) in the hippocampus of SI group were higher than those in GH group.Compared with the GH group, the expression of the neurotrophic factors IGF-1 mRNA in the SI group was down-regulated ((0.73±0.07), (1.00±0.08); t=2.327, P<0.05), while the expression of LCN2 mRNA((1.12±0.03), (1.00±0.03), t=2.575, P<0.05), IL-1β mRNA(1.76±0.19), (1.00±0.07), t=3.460, P<0.01) and TNF-α mRNA((2.18±0.42), (1.00±0.07), t=2.427, P<0.05) were up-regulated in the SI group. Conclusion:The pathological mechanism of social isolation-induced cognitive impairment in mice may be related with the phenotypic changes of astrocytes.
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Objective:To investigate the effects of excessive fluoride exposure on astrocytes and the expression of glial fibrillary acidic protein (GFAP), in vitro and in vivo. Methods:(1) In vivo experiment: 24 SPF SD rats, half male and half female, were randomly divided into control and fluoride exposed groups according to sex and body weight, 12 rats in each group. Rats were fed with < 1 mg/L and 50 mg/L sodium fluoride solution prepared by tap water for 6 months, respectively. The expression levels of GFAP protein in rat brain tissue were measured by immunofluorescence, immunohistochemistry and Western blotting. (2) In vitro experiment: adult (6-month-old) rat cortical astrocytes were extracted and cultured in primary culture (4 mmol/L sodium fluoride solution for 24 h), and the astrocytes were identified by immunofluorescence, and GFAP mRNA and protein expression levels were detected by real-time fluorescence quantitative PCR and Western blotting, respectively, and astrocytes apoptosis and calcium ion content were detected by flow cytometry. Results:(1) In vivo experiment: the results of immunofluorescence, immunohistochemistry and Western blotting showed that the GFAP protein expression level in brain tissue of rats exposed to fluoride was higher than that of control group (0.440 ± 0.200 vs 0.250 ± 0.120, t =-5.93, P = 0.027; 0.270 ± 0.020 vs 0.240 ± 0.050, t =-4.87, P = 0.040; 1.017 ± 0.001 vs 0.486 ± 0.006, t =-52.48, P = 0.001). (2) In vitro experiment: GFAP positive cells were identified as astrocytes by immunofluorescence; GFAP mRNA expression level was higher in fluoride exposed group than that of control group by real-time fluorescence quantitative PCR (2.780 ± 0.120 vs 0.134 ± 0.005, t =-37.84, P = 0.001). The Western blotting results showed that the GFAP protein expression level was higher in fluoride exposed group than that of control group (2.76 ± 0.10 vs 1.38 ± 0.05, t =-20.44, P = 0.002). Flow cytometry results showed that the apoptosis rate of astrocytes was higher in fluoride exposed group than that of control group (%: 55.0 ± 1.0 vs 3.5 ± 0.6, t =-10.28, P = 0.009) and the calcium ion content was lower than that of control group (%: 54 ± 9 vs 72 ± 13, t = 4.64, P = 0.043). Conclusion:Excessive fluoride exposure causes increased GFAP expression in astrocytes in vitro and in vivo, promotes apoptosis, and affects calcium signaling pathways.
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Objective:To establish Sprague-Dawley (SD) rat models of cognitive impairment through repeated stimulation of lipopolysaccharide (LPS) in the early brain development, and to inquire into the effect of " multi-hits" mediated by inflammatory response on the histology and behavior of SD rat models and related molecular mechanisms.Methods:This study adopted a group design for experiments.The " multi-hits" SD rat models were established by intraperitoneal injection of LPS.According to the random number table method, 24 pregnant rats were randomly divided into 4 groups: control group, LPS1 group, LPS2 group and LPS3 group, 6 rats in each group.In the control group, saline was intraperitoneally injected into rats with gestational age of 18 days and 20-day-old neonatal rats.Rats with gestational age of 18 days were intraperitoneally injected with saline in the LPS1 group, 0.05 mg/kg LPS in the LPS2 group, and 0.1 mg/kg LPS in the LPS3 group.The pups in LPS1-3 groups were all injected intraperitoneally with 1 mg/kg LPS at the postnatal age of 20 days.The motor and cognitive function of the pups were evaluated overall by behavioral experiments such as forelimb suspension tests, grid tests and water maze tests.The relative expression of glial fibrillary acidic protein (GFAP), Notch1 and Jagged1 in brain tissue of pups was mainly detected by Western blot (WB) and histological experiments.One-way ANOVA analysis of variance and independent samples t- test were used to compare data among groups and between groups, respectively. Results:(1) Behavioral experiments: compared with the control group, LPS1-3 groups showed progressive decrease in forelimb suspension time [(34.81±5.66) s, (22.47±4.35) s, and (13.20±4.25) s vs.(43.88 ± 4.85) s], and the number of missteps in the grid experiment increased progressively (16.13±2.90, 20.75±3.10, 25.13±4.45 vs.9.00±2.72). The differences were statistically significant ( F=69.77, 35.59, all P<0.001). Both the escape latency and total distance in Morri′s water maze test increased progressively ( P<0.05). (2) WB experiment: the relative expression levels of GFAP, Notch1 and Jagged1 proteins in LPS1-3 groups were significantly higher than that in the control group ( P<0.05). (3) Hematoxylin-eosin (HE) staining and electron microscope pathology: compared with the control group, LPS1-3 groups had more loosely arranged frontal cortices and more obvious cell pyknosis.Under the electron microscope, the cytoplasm was swelling to varying degrees, mitochondrial cristae were broken, and part of the nuclear membrane was damaged. Conclusions:In the " multi-hits" cognitive impairment model, the damage to the brain tissue structure and behavioral changes of pups may be related to the up-regulation of Notch1/Jagged1 pathway mediated by repeated exposure to LPS.
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Objective To study the effects of TYRO protein kinase-binding protein (TYROBP) deficiency on learning behavior, glia activation and pro-inflammatory cycokines, and Tau phosphorylation of a new Alzheimer's disease (AD) mouse model carrying a PSEN1 p.G378E mutation.Methods A new AD mouse model carrying PSEN1 p.G378E mutation was built based on our previously found AD family which might be ascribed to the PSEN1 mutation, and then crossed with TYROBP deficient mice to produce the heterozygous hybrid mice (PSEN1G378E/WT; Tyrobp+/-) and the homozygous hybrid mice (PSEN1G378E/G378E; Tyrobp-/-). Water maze test was used to detect spatial learning and memory ability of mice. After the mice were sacrificed, the hippocampus was excised for further analysis. Immunofluorescence was used to identify the cell that expresses TYROBP and the number of microglia and astrocyte. Western blot was used to detect the expression levels of Tau and phosphorylated Tau (p-Tau), and ELISA to measure the levels of pro-inflammatory cytokines. Results Our results showed that TYROBP specifically expressed in the microglia of mouse hippocampus. Absence of TYROBP in PSEN1G378E mutation mouse model prevented the deterioration of learning behavior, decreased the numbers of microglia and astrocytes, and the levels of interleukin-6, interleukin-1β and tumor necrosis factor-α in the hippocampus (all P < 0.05). The ratios of AT8/Tau5, PHF1/Tau5, pT181/Tau5, pT231/Tau5 and p-ERK/ERK were all higher in homozygous hybrid mice (PSEN1G378E/G378E; Tyrobp-/- mice) compared with PSEN1G378E/G378E mice (all P < 0.05). Conclusions TYROBP deficiency might play a protective role in the modulation of neuroinflammation of AD. However, the relationship between neuroinflammation processes involving microglia and astrocyte activation, and release of pro-inflammatory cytokines, and p-Tau pathology needs further study.