Wakate Dojo

Wakate Dojo シナプス、神経系の発生・再生、その他

1DJ3-1 Cholinergic Grb2-associated-binding protein 1 regulates cognitive function via SK channel Xiu-xiu Liu¹，Nan-nan Lu²，Chao Tan²，Feng Han²，Ying-mei Lu¹ ¹Sch Med, Zhejiang Univ City College，²College Pharm Sci, Zhejiang Univ Grb2-associated-binding protein 1 (Gab1) is a member of the docking/scaffolding molecules known to play an important role in cell growth and survival. Its function in the central nervous system, however, remains unclear. We designed genetic strategies to induce a selective Gab1 deletion in cholinergic neuronal populations in mice. The cellular and network consequences of these deletion were assessed by combining immunohistochemical assays, Western blot analysis, electrophysiology and behavioral assessments. Here, we report that Gab1 is enriched in cholinergic neurons in the adult mouse brain. The cholinergic cell-specific inactivation of Gab1 (ChATCre;Gab1f/f) leads to impaired hippocampal long-term potentiation, deficits in learning and memory, and increased firing in slow-firing cholinergic neurons. Moreover, we identify abnormal small conductance Ca2+-activated K+ channels (SK channels) contributes to increased firing in cholinergic neurons in medial septum of ChAT-Cre;Gab1f/f mice. The selective ablation of Gab1 in the medial septum using AAV also leads to memory deficits. On the other hand, the overexpression of Gab1 in the medial septum partially rescues the cognitive dysfunction in ChATCre;Gab1f/f mice. Together, these findings identify the cholinergic localization of Gab1 and indicate a critical role of Gab1 in cognitive function. This suggests that the modulation of Gab1 signaling may lead to novel therapeutic strategies to ameliorate cognitive deficits associated with cholinergic neuron degeneration in Alzheimer’s disease and other neurodegenerative disorders.		1DJ3-2 Subicular neurons mediates the genesis of refractory temporal lobe epilepsy and its seizure prediction Ceng-lin Xu，Shuang Wang，Yi Wang，Zhong Chen Dept Pharmacol, Key Lab of Ministry of Health in China, Sch Med, Zhejiang Univ Despite the use of existing anti-epileptic drugs, still one-thirds of epileptic patients are drug resistant. In temporal lobe epilepsy (TLE), the ratio is even higher. The genesis of refractory temporal lobe epilepsy is complex, needs further investigation. In this study, by using in vivo neural activity recording in a classic phenytoin resistant TLE model, we found that phenytoin did not inhibit the firing activity of subicular neurons in drug resistant rats; while the firing activity of subicular neurons were inhibited in drug-responsive rats. Further selectively inhibiting subicular neurons by optogenetics could reverse drug resistance; while selectively activating subicular neurons could induce drug resistance in drug responsive rats. These results suggest that subicular neurons might mediate the genesis of drug resistance in temporal lobe epilepsy. On the other hand, seizure prediction of refractory temporal lobe epilepsy is crucial for giving timely anti-epileptic treatments. Lack of effective biomarkers makes seizure prediction difficult. High-frequency oscillations (HFOs, 80-700 Hz) are promising biomarkers for epileptic foci. By recording and analyzing EEGs from pilocarpine refractory TLE animal models, we found that the rate of ripples (80–250 Hz) decreased during 1 min before the seizure onset, which was primarily due to the reduction of type II (in-dependent of epileptiform discharges) rather than type I ripples (superimposed on epileptiform activities). Furthermore, the “ripple reduction” phenomenon was also observed in refractory TLE patients. These results indicate that ripples may potentially be helpful for predicting seizures in refractory TLE.

1DJ3-3 The Neuroprotection of KY226 on Cerebral Ischemia Injury is mediated by Akt/eNOS and ERK signaling Meiling Sun，Yasuharu Shinoda，Kohji Fukunaga Dept Pharmacol. Grad Sch Pharm Sci, Tohoku Univ Akt (Protein kinase B), a serine/threonine kinase, plays a critical role in the modulation of cell development, growth, and survival. Akt phosphorylation mediates a neuroprotective effect against ischemic injury. A novel PTP1B inhibitor KY226 elicits anti-diabetic and anti-obesity effects in male mice via enhancement of insulin signaling (J Pharmacol Sci 124:230P). We previously reported that PTP1B inhibitor sodium orthovanadate rescues neurons from delayed neuronal death in brain ischemia (J Cereb Blood Flow Metab 2001). Therefore, we hypothesize that a novel biphenyl derivative, KY226, low molecular compound, would ameliorate ischemia/reperfusion insult. The present study was designed to investigate the neuroprotective effects of KY226 in rodent ischemic stroke model by middle cerebral artery occlusion (MCAO). ICR mice were subjected to MCAO for 2 h followed by reperfusion. The KY226 treatments elicited lower infract volume than those in vehicle groups in a dose-dependent manner. Studies in mice also suggested that 10 mg/kg KY226 was effective for decreasing ischemic brain damage when administered within 0.5 h after reperfusion. KY226 (10mg/kg) could up-regulate the reduced Akt phosphorylation and eNOS phosphorylation (Ser1177) level after ischemia/reperfusion insult in ICR mice. In addition, 10 mg/kg KY226 administration improved I/R-induced decreased ERK phosphorylation. Furthermore, KY226 also attenuated the ROS stress induced by ischemic damage in mice. The suppression of oxidative stress by KY226 was produced through activation of Akt and ERK activity. The current results suggest that KY226 provides a novel therapeutic candidate for ischemic stroke. Activation of Akt and ERK activities possibly underlie the neuroprotection by KY226.		1DJ3-4 The Mechanism Underlying Cognitive Impairment in Hypothyroid Mice Noreen Husain，Yasushi Yabuki，Kohji Fukunaga Department of Pharmacology, Graduate School of Pharmaceutical & Faculty of Pharmaceutical Sciences Methimazole (MMI) is a first-line therapy used to manage hyperthyroidism and Graves’ disease. Despite its therapeutic benefit, chronic MMI administration can lead to hypothyroidism and perturb brain homeostasis in patients, resulting in neuropsychiatric disorders such as depression and cognitive dysfunction. We recently developed the spiroimidazopyridine derivative SAK3 as cognitive enhancer; however, mechanisms underlying its activity remained unclear. Here, we show that SAK3 potentially improves cognitive impairment seen following MMI-induced hypothyroidism. Twenty-four hours after MMI (75 mg/kg, i.p.) treatment, we administered SAK3 (0.1, 0.5 and 1 mg/kg,p.o.) to mice daily for 7 days. MMI treatment alone disrupted olfactory bulb (OB) glomerular structure, as assessed by staining with the olfactory marker protein (OMP), reduced the number of choline acetyl transferase (ChAT)-immunoreactive neurons in medial septum (MS), and significantly impaired cognition. SAK3 (0.5 and 1 mg/kg, p.o.) administration significantly restored the number of cholinergic MS neurons in MMI-treated mice, and SAK3 treatment at a higher dose significantly improved cognitive deficits seen in MMI-treated control mice. Overall, our study defines mechanisms underlying cognitive impairment by hypothyroidism and suggests that SAK3 treatment could antagonize such impairment in patients with hypothyroidism.

1DJ3-5 Wnt signaling regulates neurogenesis from radial glia in the adult zebrafish optic tectum after traumatic brain injury Yuki Shimizu，Yuto Ueda，Toshio Ohshima Dept. of Life Sci. and Med. Bio-Sci. Waseda Univ. Zebrafish have great abilities to regenerate brain after the brain injury compared to mammalian. We established the traumatic brain injury (TBI) model in the optic tectum and analyzed the brain regeneration after TBI. We confirmed that the induction of RG proliferation and the differentiation of RG into new-born neurons after TBI. Then, we analyzed Wnt signaling after TBI by using Wnt reporter line in which canonical Wnt signaling induced GFP expression, and we confirmed that GFP was expressed specifically in RG after TBI in optic tectum. Wnt signaling is well known to regulate stem cell proliferation and differentiation during development and also contributes to the tissue regeneration. However, the roles of Wnt signaling during optic tectum regeneration after TBI are not well know. In this study, we analyzed the roles of wnt signaling in the proliferation and differentiation of RG after TBI. We treated zebrafish with the Wnt inhibitor, IWR after TBI and analyzed the proliferation and differentiation of RG. The number of proliferative RG or new-born neurons was significantly decreased compared with that with DMSO treatment. These results suggest that Wnt signaling regulates the brain regeneration after TBI in the optic tectum. To analyze the effect of Wnt signal activation in the physiological brain, we also treated uninjured zebrafish with GSK3β inhibitor BIO for 2days and confirmed that the number of proliferative RG was significantly increased in the anterior parts of optic tectum. However, the number of proliferative RG was less than that of injured zebrafish suggesting that Wnt signaling cooperatively regulates RG proliferation with another molecular mechanisms after TBI.		1DJ3-6 Neonatal allergen exposure induces autistic-like behavior via hippocampal synaptopathy in mice Ban-yu Saitoh¹，Daan Van Kruining²，Ryo Yamasaki¹，Jun-ichi Kira¹ ¹Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu university，²School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Maastricht University Background: Allergic diseases and neurodevelopmental disorders are both rapidly increasing in advanced countries. Several epidemiological surveys suggested increased prevalence of allergic diseases in autism (ASD). We hypothesized that allergy may enhance susceptibility to neurodevelopmental disorders. We aimed to clarify whether neonatal allergen exposure could affect behavior and brain pathology in mice.Methods: On day 1, dams (four-week-old C57BL/6J mice) received 1 mg of alum by intraperitoneal injection. On day 14, dams were given a second alum injection and mated the next day. From postnatal day 3 (P3), pups received inhalation of phosphate-buffered saline (sham group) or ovalbumin (OVA group) for 30 min/day three times/week. After weaning on P21, the following behavioral assays were conducted: three-chamber test (TCT), self-grooming test (SGT), marble-burying test (MBT), open-field test (OFT), and novel object recognition test (NORT). In addition, synapse-related proteins were quantified on P14 by western blotting using hippocampal tissue.Results: In the TCT, males but not females in the OVA group spent significantly shorter times in the stranger chamber compared with control mice, suggesting decreased sociability. Similarly, in the SGT and MBT, only male in the OVA group spent significantly longer time in self-grooming and buried significantly more marbles than control mice. No significant differences were observed in the OFT and NORT. Synapse-related proteins (e.g., SynGap) were significantly downregulated in hippocampus of OVA group males compared with control mice.Conclusions:Present study suggest that neonatal allergy can impair normal synaptogenesis, inducing autism-like behavior, especially in male, which was in line with human ASD.

1DJ3-7 Relation of Wnt related molecules in non-Alzheimer's degenerative diseases Yuhei Kanaya，Tetsuya Takahashi，Yukari Murata，Tomoyasu Matsubara，Tejashwi Shresta，Seigyoku Lee，Hirofumi Maruyama Dept Neuroscience, Grad Sch biomed and health sci,Hiroshima Univ 【Background】In Alzheimer's disease (AD), granulovacuolar degeneration(GVD) bodies are recognized as a pathological feature along with senile plaque and neurofibrillary tangle. We presume that the GVD bodies are derived from strutures common to muscle cells and neurons such as neuromuscular junction (NMJ) and postsynaptic spine. Previously, we reported that Wnt related molecules involved in the formation of synapses and NMJ are present in GVD of the AD. However, it has not been clarified whether Wnt related molecules exist in GVD in degenerative diseases other than AD such as Parkinson's disease with dementia (PDD), Corticobasal degeneration (CBD), Progressive supranuclear palsy (PSP) and myotonic dystrophy (MyD). In this study, we invesigated the localization of Wnt related molecules in GVD of degenerative disease other than AD and explored of Wnt related molecules in GVD is pathology specific or disease specific.【Methods】Subjects included two cases of PDD, one case of CBD, one case of PSP and two cases of MyD. We compared immunoreactivity and staining patterns for antibodies which are confirmed to exist in GVD of the AD such as dishevelled3 (Dvl3), phosho-β-catenin, rapsyn, axin2, adenomatous polyposys coil (APC) and phosphatidylinositol 4,5-bisphosphate (PIP2).【Results】All cases were immunopositive for Dvl3, phosho-β-catenin, rapsyn, APC and PIP2. Axin2 was immunonegative in all cases.【Conclsion】Wnt related molecules excluding axin2 were present in GVD in all diseases. The fact that Wnt was also present in these degenerative diseases as with AD suggests that Wnt related molecules are not disease specific to AD and that of Wnt related molecules are located in the common pathway of GVD formation in various degenerative diseases.