Basal Forebrain Cholinergic Innervation Induces Depression-Like Behaviors Through Ventral Subiculum Hyperactivation / 神经科学通报·英文版

Malfunction of the ventral subiculum (vSub), the main subregion controlling the output connections from the hippocampus, is associated with major depressive disorder (MDD). Although the vSub receives cholinergic innervation from the medial septum and diagonal band of Broca (MSDB), whether and how the MSDB-to-vSub cholinergic circuit is involved in MDD is elusive. Here, we found that chronic unpredictable mild stress (CUMS) induced depression-like behaviors with hyperactivation of vSub neurons, measured by c-fos staining and whole-cell patch-clamp recording. By retrograde and anterograde tracing, we confirmed the dense MSDB cholinergic innervation of the vSub. In addition, transient restraint stress in CUMS increased the level of ACh in the vSub. Furthermore, chemogenetic stimulation of this MSDB-vSub innervation in ChAT-Cre mice induced hyperactivation of vSub pyramidal neurons along with depression-like behaviors; and local infusion of atropine, a muscarinic receptor antagonist, into the vSub attenuated the depression-like behaviors induced by chemogenetic stimulation of this pathway and CUMS. Together, these findings suggest that activating the MSDB-vSub cholinergic pathway induces hyperactivation of vSub pyramidal neurons and depression-like behaviors, revealing a novel circuit underlying vSub pyramidal neuronal hyperactivation and its associated depression.

Illuminating Neural Circuits in Alzheimer’s Disease / 神经科学通报·英文版

Alzheimer’s disease (AD) is the most common neurodegenerative disorder and there is currently no cure. Neural circuit dysfunction is the fundamental mechanism underlying the learning and memory deficits in patients with AD. Therefore, it is important to understand the structural features and mechanisms underlying the deregulated circuits during AD progression, by which new tools for intervention can be developed. Here, we briefly summarize the most recently established cutting-edge experimental approaches and key techniques that enable neural circuit tracing and manipulation of their activity. We also discuss the advantages and limitations of these approaches. Finally, we review the applications of these techniques in the discovery of circuit mechanisms underlying β-amyloid and tau pathologies during AD progression, and as well as the strategies for targeted AD treatments.

Folate/Vitamin B Alleviates Hyperhomocysteinemia-Induced Alzheimer-Like Pathologies in Rat Retina / 神经科学通报·英文版

Hyperhomocysteinemia (Hhcy) is an independent risk factor for Alzheimer's disease (AD). Visual dysfunction is commonly found and is positively correlated with the severity of cognitive defects in AD patients. Our previous study demonstrated that Hhcy induces memory deficits with AD-like tau and amyloid-β (Aβ) pathologies in the hippocampus, and supplementation with folate and vitamin B12 (FB) prevents the Hhcy-induced AD-like pathologies in the hippocampus. Here, we investigated whether Hhcy also induces AD-like pathologies in the retina and the effects of FB. An Hhcy rat model was produced by vena caudalis injection of homocysteine for 14 days, and the effects of FB were assessed by simultaneous supplementation with FB in drinking water. We found that Hhcy induced vessel damage with Aβ and tau pathologies in the retina, while simultaneous supplementation with FB remarkably attenuated the Hhcy-induced tau hyperphosphorylation at multiple AD-related sites and Aβ accumulation in the retina. The mechanisms involved downregulation of amyloid precursor protein (APP), presenilin-1, beta-site APP-cleaving enzyme 1, and protein phosphatase-2A. Our data suggest that the retina may serve as a window for evaluating the effects of FB on hyperhomocysteinemia-induced Alzheimer-like pathologies.

Liraglutide Ameliorates Hyperhomocysteinemia-Induced Alzheimer-Like Pathology and Memory Deficits in Rats via Multi-molecular Targeting / 神经科学通报·英文版

Hyperhomocysteinemia (Hhcy) is an independent risk factor for Alzheimer's disease (AD), and insulin-resistance is commonly seen in patients with Hhcy. Liraglutide (Lir), a glucagon-like peptide that increases the secretion and sensitivity of insulin, has a neurotrophic or neuroprotective effect. However, it is not known whether Lir ameliorates the AD-like pathology and memory deficit induced by Hhcy. By vena caudalis injection of homocysteine to produce the Hhcy model in rats, we found here that simultaneous administration of Lir for 2 weeks ameliorated the Hhcy-induced memory deficit, along with increased density of dendritic spines and up-regulation of synaptic proteins. Lir also attenuated the Hhcy-induced tau hyperphosphorylation and Aβ overproduction, and the molecular mechanisms involved the restoration of protein phosphatase-2A activity and inhibition of β- and γ-secretases. Phosphorylated insulin receptor substrate-1 also decreased after treatment with Lir. Our data reveal that Lir improves the Hhcy-induced AD-like spatial memory deficit and the mechanisms involve the modulation of insulin-resistance and the pathways generating abnormal tau and Aβ.

Tau-Induced Ca/Calmodulin-Dependent Protein Kinase-IV Activation Aggravates Nuclear Tau Hyperphosphorylation / 神经科学通报·英文版

Hyperphosphorylated tau is the major protein component of neurofibrillary tangles in the brains of patients with Alzheimer's disease (AD). However, the mechanism underlying tau hyperphosphorylation is not fully understood. Here, we demonstrated that exogenously expressed wild-type human tau40 was detectable in the phosphorylated form at multiple AD-associated sites in cytoplasmic and nuclear fractions from HEK293 cells. Among these sites, tau phosphorylated at Thr205 and Ser214 was almost exclusively found in the nuclear fraction at the conditions used in the present study. With the intracellular tau accumulation, the Ca concentration was significantly increased in both cytoplasmic and nuclear fractions. Further studies using site-specific mutagenesis and pharmacological treatment demonstrated that phosphorylation of tau at Thr205 increased nuclear Ca concentration with a simultaneous increase in the phosphorylation of Ca/calmodulin-dependent protein kinase IV (CaMKIV) at Ser196. On the other hand, phosphorylation of tau at Ser214 did not significantly change the nuclear Ca/CaMKIV signaling. Finally, expressing calmodulin-binding protein-4 that disrupts formation of the Ca/calmodulin complex abolished the okadaic acid-induced tau hyperphosphorylation in the nuclear fraction. We conclude that the intracellular accumulation of phosphorylated tau, as detected in the brains of AD patients, can trigger nuclear Ca/CaMKIV signaling, which in turn aggravates tau hyperphosphorylation. Our findings provide new insights for tauopathies: hyperphosphorylation of intracellular tau and an increased Ca concentration may induce a self-perpetuating harmful loop to promote neurodegeneration.

LC3 protein expression and localization in mouse follicular granulosa cells / 中国病理生理杂志

AIM:To investigate the expression and localization of autophagy related protein microtublule associated protein 1 light chain 3 (LC3) at various stages of follicular development and atresia in the mice.METHODS:On 0,1,2,3,4 and 5 day after intraperitoneal injection of pregnant mare serum gonadotropin (PMSG),expression and positioning situation of autophagy related protein LC3 and apoptosis related protein cleaved caspase-3 were examined by the method of immunohistochemical staining.The protein levels of cleaved caspase-3 and LC3 were determined by Western blot in cultured mouse granulosa cells after incubation under serum-free conditions in the absence or presence of FSH.LC3 subcellular localization in granulosa cells were studied by the method of immunofluorescence.RESULTS:The LC3 protein expressed in granulosa cells during all developmental stages mainly.Granulosa cells of atretic follicles that showed intense staining of cleaved caspase-3 and LC3.The protein levels of cleaved caspase-3 and LC3-Ⅱ in the granulosa cells significantly decreased at 1 d and 2 d after intraperitoneal injection of PMSG (P ＜ 0.05).The protein levels of cleaved caspase3 and LC3-Ⅱ in the granulosa cells increased in turn on 3,4 and 5 day after intraperitoneal injection of PMSG.The positive correlation between LC3-Ⅱ and cleaved caspase-3 protein levels was observed (r2 =0.8299,P ＜ 0.05).The LC3-Ⅱ protein expressed with punctuate structures in granulosa cell cytoplasm cultured under serum-free conditions in the presence of FSH.CONCLUSION:LC3 is expressed in the follicular granulosa cells with cell specificity and regional specificity.Autophagy is induced mainly in granulosa cells during folliculogenesis and shows positive correlation with apoptosis.Ovarian granulosa cell autophagy and apoptosis are gonadotropic hormone dependent.

LC3 protein expression and localization in mouse follicular granulosa cells / 中国病理生理杂志

AIM:To investigate the expression and localization of autophagy related protein microtublule associated protein 1 light chain 3 (LC3) at various stages of follicular development and atresia in the mice.METHODS:On 0,1,2,3,4 and 5 day after intraperitoneal injection of pregnant mare serum gonadotropin (PMSG),expression and positioning situation of autophagy related protein LC3 and apoptosis related protein cleaved caspase-3 were examined by the method of immunohistochemical staining.The protein levels of cleaved caspase-3 and LC3 were determined by Western blot in cultured mouse granulosa cells after incubation under serum-free conditions in the absence or presence of FSH.LC3 subcellular localization in granulosa cells were studied by the method of immunofluorescence.RESULTS:The LC3 protein expressed in granulosa cells during all developmental stages mainly.Granulosa cells of atretic follicles that showed intense staining of cleaved caspase-3 and LC3.The protein levels of cleaved caspase-3 and LC3-Ⅱ in the granulosa cells significantly decreased at 1 d and 2 d after intraperitoneal injection of PMSG (P ＜ 0.05).The protein levels of cleaved caspase3 and LC3-Ⅱ in the granulosa cells increased in turn on 3,4 and 5 day after intraperitoneal injection of PMSG.The positive correlation between LC3-Ⅱ and cleaved caspase-3 protein levels was observed (r2 =0.8299,P ＜ 0.05).The LC3-Ⅱ protein expressed with punctuate structures in granulosa cell cytoplasm cultured under serum-free conditions in the presence of FSH.CONCLUSION:LC3 is expressed in the follicular granulosa cells with cell specificity and regional specificity.Autophagy is induced mainly in granulosa cells during folliculogenesis and shows positive correlation with apoptosis.Ovarian granulosa cell autophagy and apoptosis are gonadotropic hormone dependent.

Mechanism of tau hyperphosphorylation in brain cortex of diabetic rats and effect of LiCl / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the mechanism of tau hyperphosphorylation and the effect of LiCl on tau phosphorylation and the memory retention deficits in streptozotocin-induced diabetes mellitus (DM) rats.</p><p><b>METHODS</b>The rats were randomly divided into control, DM, DM + NaCl, and DM + LiCl groups and diabetes was induced by streptozotocin. The activity of glycogen synthase kinase-3 (GSK-3) was measured by 32P-labelling. The level of tau phosphorylated and changes of memory retention were examined by Western blotting and step down test, respectively.</p><p><b>RESULTS</b>Compared with control group, the activity of GSK-3 and tau phosphorylation was increased, and the memory retention was impaired in DM group. When the rats were treated with LiCl, the activity of GSK-3 and hyperphosphorylation of tau were significantly arrested (P < 0.05, P < 0.01), and the memory retention deficit was significantly improved (P < 0.05).</p><p><b>CONCLUSION</b>The hyperphosphorylation of tau can be induced by activation of GSK-3 in diabetic rats. Lithium protects tau from hyperphosphorylation and may rescue memory retention in the rats by inhibiting GSK-3 activity.</p>

Duration of tau hyperphosphorylation and spatial memory deficit induced by single injection of Forskolin into lateral ventricle of rat / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the duration of tau hyperphosphorylation and spatial memory retentive deficit induced by single injecting with Forskolin, a protein kinase A activator, into lateral ventricle of rats, and the correlation between the two pathological alterations.</p><p><b>METHODS</b>Forskolin (80 micromol/L, 40 microl) was injected into the lateral ventricle by stereotaxic injection. Tau phosphorylation and spatial memory retention were measured by Western blot/immunocytochemistry and Morris-Water-Maze test, respectively.</p><p><b>RESULTS</b>The phosphorylation levels of tau at Tau-1, PHF-1, and pS214 epitopes were significantly elevated at 24, 48 and 72 h after single administration of Forskolin (P < 0.05). The most significant elevation was seen at 48 h (P < 0.01) and it tended to recover at 72 h (P < 0.05) after injection. The correlation between the two pathological alterations was positive at PHF-1 site (r = 0.97, P < 0.05), negative at Tau-1 site (r = -0.963, P < 0.05), and not significant at pS214 site (r = 0.705, P > 0.05).</p><p><b>CONCLUSIONS</b>Forskolin can induce tau hyperphosphorylation and spatial memory retentive deficit within a certain period of time. The level of tau phosphorylation in hippocampus is somehow correlated with the spatial memory deficit in rats.</p>

Effect of flying burthen on blood lipid in civil aviation aircrew / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effect of flying burthen on blood lipid level in civil aviation flight personnel.</p><p><b>METHODS</b>The level of total cholesterol (TC), triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) were determined by kits. The relationship between the blood lipid levels and the flight personnel's flying hours, body weight index, smoking, drinking and sport were investigated.</p><p><b>RESULTS</b>The average annual flying hours of hyperlipidemia group [(561.14 +/- 234.90) h] was significantly higher than that of non-hyperlipidemia group [(500.62 +/- 243.65) h] (P < 0.05). The level of TG of the average annual flying hours more 800 h [(1.61 +/- 0.10) mmol/L] were significantly higher than that of less than 400 h group [(1.31 +/- 0.65) mmol/L]. The morbidity rate of hyperlipidemia among the age 30 to 39 years old flight personnel was the highest.</p><p><b>CONCLUSION</b>The average annual flying hours is one of primary factors affecting blood lipid in flight personnel.</p>

Expressions of Tau protein during the differentiation process of mesenchymal stem cells into neural cells / 中国应用生理学杂志

<p><b>AIM</b>To observe expressions and changes of Tau protein, pSer202 and Tau protein's contents during the differentiation process of bone-marrow mesenchymal stem cells (MSCs) into neural cells, and discuss Tau's effects on it.</p><p><b>METHODS</b>EGF and bFGF were combined for the induction of 4th, 8th, and 12th-MSCs into neural cells. Expressions of Tau protein and pSer202 were tested by immunocytochemistry. ELISA assay was applied for testing Tau protein's contents during differentiation process.</p><p><b>RESULTS</b>Positive rates of Tau protein in uninduced MSCs of 4th, 8th, and 12th-MSCs were under < 6%; After 14-day induction, the cellular morphologic characteristics in different passages were very similar to neurons, positive rates of Tau protein had no significant differences between passages (P > 0.05), but had differences with their uninduced groups (P < 0.05). There hadn't had expression of pSer202 in uninduced and induced groups of passages. ELISA assay indicated that there was an upward tendency in Tau protein's contents during the 14-day induction process, those in the 14th day had no significant differences between passages too (P > 0.05).</p><p><b>CONCLUSION</b>The increase in Tau protein's expressions and its non-phosphorylated state may make for MSCs differentiating into normal neural cells and formation of neuronal processes.</p>

Effect of five species of Epimedium on growth of cartilage and proliferation of cartilage cell in vitro / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effect of Epimedium brevicornum, E. sagittatum, E. koreanum, E, wushanense and E. elongntum on the growth of cartilage and proliferation of cartilage cell in vitro.</p><p><b>METHOD</b>According to the paired design method, either femur of each chichen embryo was put into the control tube with the medium containing no Epimedium injection, and the other was put into the treated tube with the medium containing 3% Epimedium injection. The length and weight of cultured cartilage and proliferation of cartilage cell (MTY method) were used as the indices to observe the cartilage biological activities of the five species of Epimedium in culture.</p><p><b>RESULT</b>The results showed that the indices of length, weight and MTT in the E. brevicornum and E. sagittatum group were significantly higher than those in the contral group, but the above indices in groups E. koreanum, E. wushanens and E. elongntum were similar to those of the control with no statistical difference.</p><p><b>CONCLUSION</b>E. brevicornum and E. sagittatum can improve the growth of cartilage and proliferation of cartilage cell in vitro, and other three Epimedium have not the same effect in this test.</p>

Prevention of isoproterenol-induced tau hyperphosphorylation by melatonin in the rat / 生理学报

Hyperphosphorylated microtubule-associated protein tau is the major protein component of neurofibrillary tangles in the brain of patients with Alzheimer's disease (AD). Until now, there is no effective cure to arrest this hyperphosphorylation. The present study was designed to explore the in vivo preventive effect of melatonin on Alzheimer-like tau hyperphosphorylation. Isoproterenol, a beta-receptor agonist, was used to induce tau hyperphosphorylation, and for preventive effect of melatonin, the rats were injected intraperitoneally with melatonin for 5 d before hippocampi infusion of isoproterenol. The level of tau phosphorylation was detected by Western blot and immunohistochemistry using sites specific antibodies (PHF-1 and Tau-1), and it was normalized by non-phosphorylation dependent total tau antibody (111e). The results by Western blot showed that the immunoreaction of tau at PHF-1 epitope was enhanced, and the reaction at Tau-1 epitope was weakened significantly at 48 h after injection of isoproterenol, suggesting hyperphosphorylation of tau at Ser 396/Ser 404 (PHF-1) and Ser199/Ser 202 (Tau-1) sites. Similar results were observed by immunohistochemistry staining, in which hyperphosphorylated tau was mainly detected in mossy fibers of hippocampal CA3 region. Pre-injection of rats with melatonin intraperitoneally arrested effectively the isoproterenol-induced tau hyperphosphorylation at both Tau-1 and PHF-1 sites, implying the preventive effect of melatonin in Alzheimer-like tau hyperphosphorylation.

Effect of different culture media on viability and tau protein expression in rat hippocampal slices / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the effect of different culture media on viability and expression of tau protein in organotypic hippocampal slice.</p><p><b>METHODS</b>Brain slices (400 microm) from 1, 2, 4, and 8 week-old Wistar rats were prepared and cultured in minimum essential medium (MEM) or Dulbecco's modified eagle medium: nutrient mixture (DMEM/F12) medium respectively for 21 days. Viability of the slices was measured by lactate dehydrogenase (LDH) assay and expression of tau protein was detected by Western blot.</p><p><b>RESULTS</b>The viability of the slices was not influenced significantly by the two different culture media, while the expression level of tau protein was significantly higher in DMEM/F12 than in MEM (P < 0.05), especially in the slices from 2 and 4 week-old rats.</p><p><b>CONCLUSION</b>The slices from 2 or 4 week-old rat hippocampi and DMEM/F12 medium may be the preferred choice for tau associated researches. An ideal Alzheimer's disease model may be established based on the results of these researches.</p>

Alteration of beta-amyloid and glutamate transporter in the brain of diabetes rats and the underlying mechanism / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the alteration of beta-amyloid (Abeta) and glutamate transporter in the brain cortex of diabetes mellitus (DM) rats and the underlying mechanism.</p><p><b>METHODS</b>The rats were randomly divided into control, DM, DM +NaCl, and DM +LiCl groups and diabetes was induced by streptozotocin. The activity of glycogen synthase kinase-3 (GSK-3) and the function of glutamate transporter were measured by 32P-labelling. The amount of Abeta was determined by enzyme-linked immunosorbentassay.</p><p><b>RESULTS</b>In DM group, the level of Abeta40 increased (P < 0.01), but the function of glutamate transporter was impaired (P < 0.05). The activity of GSK-3 was stimulated (P < 0.05). Compared with DM group, the level of Abeta40 was restored (P < 0.01), and the function of glutamate transporter was enhanced (P < 0.05) in LiCl treated group, accompanied by a decreased activity of GSK-3.</p><p><b>CONCLUSION</b>Overproduction of Abeta and impaired glutamate transporter exist in DM rats, and increase of GSK-3 may play a crucial role in this process.</p>

Inhibition of melatonin biosynthesis activates protein kinase a and induces Alzheimer-like tau hyperphosphorylation in rats / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate effect of inhibiting melatonin biosynthesis on activities of protein kinase A (PKA), glycogen synthase kinase-3 (GSK-3) and tau phosphorylation at PS214 and M4 epitopes using haloperidol, a specific inhibitor of 5-hydroxyindole-O-methyltransferase.</p><p><b>METHODS</b>Brain ventricular and intraperitoneal injections were used for haloperidol administration, Western blots for tau phosphorylation, 32P-labeling for PKA and GSK-3 activity, and high performance liquid chromatograph for detection of serum melatonin levels.</p><p><b>RESULTS</b>Haloperidol injection through the lateral ventricle and intraperitoneal reinforcement significantly stimulated PKA activity with a concurrent hyperphosphorylation of tau at M4 (Thr231/Ser235) and PS214 (Ser214) sites. Prior treatment of the rats using melatonin supplement for one week and reinforcement during the haloperidol administration arrested PKA activity and attenuated tau hyperphosphorylation. GSK-3 activity showed no obvious change after haloperidol injection, however, melatonin supplements and reinforcements during haloperidol infusion inactivated basal activity of GSK-3.</p><p><b>CONCLUSION</b>Decreased melatonin may be involved in Alzheimer-like tau hyperphosphorylation, and overactivation of PKA may play a crucial role in this process.</p>

Effects of S100A4 expressed In white matter astrocytes on sensory neurite outgrowth in vitro / 中华物理医学与康复杂志

Objective To investigate the role of white matter astrocytes and their specific protein S100A4 in sensory neurite outgrowth in vitro.Methods White matter astrocyte cultures expressing S100A4 were prepared. Dissociated adult dorsal root ganglion(DRG)cells were placed on the top of the astrocytes and co-cultured for 6,12, 18,24 hours.Small interfering S100A4 RNA was used to eliminate S100A4 expression.The growth of DRG cell neu- rites on S100A4-sileneed and S100A4-expressing astrocytes was compared.Results 12,18 and 24 hours after the co-culture with S100A4-expressing or S100A4-silenced astroeytes,neurite growth from the DRG cells was observed. Neurite outgrowth was significantly greater in S100A4 siRNA treated cultures compared to control siRNA treated white matter astrocyte cultures.Conclusion These findings suggest that white matter astroeytes are able to support axonal regeneration and,furthermore,that administration of small interfering S100A4 RNA provides strong additional support for axon regeneration.