Developmental neuroimmunotoxicity: Changes in the expression of neuroimmune markers in the hippocampus of infant mice following early life toluene exposure

Abstracts / Neuroscience Research 68S (2010) e335–e446

Muscatelli, F., et al., (2000) Hum. Mol. Genet., 9:3101 Kasahara, Y., et al., (2007) Biosci. Biotechnol. Biochem., 71:3122 Takayanagi,Y., et al., (2008) Neuroreport, 19:951 doi:10.1016/j.neures.2010.07.1846

P3-n13 Screening of anti-NMDAR autoantibodies in the serum from patients with encephalitis using a heterologous NMDAR expression system Shiho Takano 1 , Yukitoshi Takahashi 2 , Hisashi Mori 1 1 Dept. Molecular Neuroscience, Grad. Sch. Med. & Pharma. Sci., University Toyama 2 Dept. Pediatrics. Nat. Epilepsy Center, Shizuoka

Anti-NMDAR antibody has been implicated in pathogenic mechanisms of autoimmune encephalitis. By the transient expression of low Ca2+ permeable mutant NMDA-type glutamate receptor subunits, the GluR␨1(NR1)N598REGFP and the GluR␧2(NR2B)N589R, or the GluR␨1(NR1)N598R-EGFP alone, we have successfully detected the surface expression of mutant NMDAR in mammalian cells. Then, we examined the presence of anti-NMDAR autoantibody in the serum from 12 patients (7 with limbic encephalitis and 5 with encephalitis associated with ovarian teratoma) with our expression system. Five of the 7 patients with limbic encephalitis and all 5 patients encephalitis associated with ovarian teratoma had the antibodies against both GluR␧2 and GluR␨1 subunits. Thus, most of examined patients have autoantibodies against GluR␧2 and GluR␨1 subunits. Furthermore, we observed that autoantibodies against NMDAR in serums from patients induced internalization of NMDAR at 37 ◦ C. From these results, the decline of NMDAR by internalization mediated by autoantibodies may be one of the pathophysiological mechanisms of abnormal behaviors, such as deficit of memory, and emotional disturbance, observed in patients of autoimmune encephalitis. doi:10.1016/j.neures.2010.07.1847

P3-n14 Autoimmunity to the sodium-level sensor in the brain causes essential hypernatremia Takeshi Y. Hiyama 1,3 , Shinichi Matsuda 4 , Akihiro Fujikawa 1 , Masahito Matsumoto 1 , Eiji Watanabe 2,3 , Hiroshi Kajiwara 5 , Fumio Niimura 4 , Masaharu Noda 1,3 1

Department Mol Neurobiol 2 Department Neurophysiol, Nat’l Inst. Basic Biol Sch Life Sci, Grad University Advanced Studies, Okazaki, Japan 4 Department Pediatrics 5 Dept Pathology,Tokai Univ Sch Med, Isehara, Japan

3

Nax is the sodium-level sensor of body-fluids in the brain involved in sodium homeostasis. Nax -knockout mice do not stop ingesting salt even when dehydrated. Here we report a case with clinical features of essential hypernatremia without demonstrable hypothalamic structural lesions, who was diagnosed as a paraneoplastic neurologic disorder. The patient had autoantibodies directed against Nax , along with a ganglioneuroma comprised of Schwann-like cells robustly expressing Nax . The removal of the tumor did not reduce the autoantibody levels or relieve the symptoms. Intravenous injection of the immunoglobulin fraction of the patient’s serum into mice induced abnormalities in water/salt-intake and diuresis, which led to hypernatremia. In the brain of these mice, cell death was observed along with focal deposits of complement C3 and inflammatory infiltrates in circumventricular organs where Nax is specifically expressed. Our findings thus provide new insights into the pathogenesis of hypernatremia relevant to the sodium-level-sensing mechanism in humans. doi:10.1016/j.neures.2010.07.1848

P3-n16 Developmental neuroimmunotoxicity: Changes in the expression of neuroimmune markers in the hippocampus of infant mice following early life toluene exposure Tin-Tin Win-Shwe 1 , Shinji Tsukahara 2 , Hidekazu Fujimaki 1 National Institute for Environmental Studies 2 Graduate School of Science and Engineering Saitama University

e417

to toluene exposure during development and the effects of fetal and neonatal toluene exposure on the expression of neurotrophic factors, proinflammatory cytokines, oxidative stress markers, astrocyte and microglia markers, and transcription factors in late infant mouse brain. Gestational day (GD) 14 pregnant mice, postnatal day (PND) 2 male offspring, and PND 8 male offspring were exposed to filtered air (control; 0 ppm) or 5 or 50 ppm of toluene for 6 h per day for five consecutive days. On PND 21, the hippocampus was collected from each male mouse to examine the various neuro-immune markers using a real-time RT-PCR analysis. Mice exposed to 50 ppm toluene on PND 2–6 showed significantly increased levels of nerve growth factor (NGF) and tumor necrosis factor (TNF)-␣ mRNAs. In contrast, NGF and brain-derived neurotrophic factor (BDNF) and proinflammatory cytokines TNF–␣, CCL3, astrocyte marker glial fibrillary acidic protein (GFAP), and microglia marker ionized calcium binding adapter molecule (Iba)-1 mRNAs were increased significantly in mice exposed to 5 ppm of toluene on PND 8–12. However, mice exposed to toluene on GD 14–18 showed no significant change. Toluene exposure during the late postnatal period might induce microglia activation and the production of proinflammatory cytokines and immune-related neurotrophins in the hippocampus of PND 21 male mice. These results indicate that mice might be particularly vulnerable and sensitive to toluene exposure during the late postnatal period (PND 8–12). doi:10.1016/j.neures.2010.07.1849

P3-n18 Long-lasting effects on hippocampal excitability of the offspring prenatally exposed to 1-bromopropane, a substitute for specific chlorofluorocarbons Yukiko Fueta 1 , Susumu Ueno 2 , Toru Ishidao 1 , Hajime Hori 1 1 Department Environmental Management, School of Health Sciences, Univ of Occupational and Environmental Health, Kitakyushu 2 Department Pharmacol, School of Medicine, Univ of Occupational and Environmental Health, Kitakyushu

1-Bromopropane (1-BP) is a volatile organic solvent used for degreasing agents and spray adhesives. Although 1-BP exhibits central neurotoxicity in adult humans (Ichihara et al., 2002; CERHR, 2004; Perrone et al., 2008) and animals (Fueta et al., 2002, 2004, 2007; Ueno et al., 2007; Yoshida et al., 2007, 2009), the effects of 1-BP exposure on development of central nervous system remain unclear. Thus, we aimed to clarify whether prenatal exposure to 1-BP affects development of neuronal excitability in the hippocampus of the offspring, and whether the effects last long or not. Pregnant Wistar rats were inhalationally exposed to 1-BP with the concentration of 0 or 700 ppm at days 1-20. In the PND14 offspring, the prenatal exposure to 1-BP increased stimulation/response (S/R) curves of field excitatory postsynaptic potential (fEPSP) slope (p < 0.001) and population spike (PS) (p < 0.001), and decreased pairedpulse ratios (PPRs) of PS at 5-20 ms interpulse intervals (IPIs) (p < 0.05) in the hippocampal CA1 region compared to the control offspring. The 5 weekold offspring exhibited a decreased S/R curve of fEPSP slope (p < 0.01). PPRs increased in fEPSP at 5 and 10 ms IPIs (p < 0.05) and decreased in PS at 5 ms IPI (p < 0.05). The female 13 week-old offspring exhibited increased PPRs of PS at 5-20 ms IPIs (p < 0.001) without changes in those of fEPSP. The male 13 week-old offspring disclosed increased PPRs at 5 ms IPI in the both fEPSP slope (p < 0.05) and PS (p < 0.05). Thus, the prenatal exposure to 1-BP resulted in the pyramidal cell disinhibition in the adult offspring. Our results suggest that disturbance of hippocampal excitability induced by prenatally exposure to 1-BP may last after maturation. doi:10.1016/j.neures.2010.07.1850

P3-n19 Diphenylarsinic acid induced oxidative stress and expression of neuroactive and vasoactive peptides in cerebellar astrocytes Takayuki Negishi 1 , Masaki Takahashi 1 , Kohshi Hiroaki Ohnishi 1 , Seishiro Hirano 2 , Tomoko Tashiro 1

Oyanagi 1 ,

1 Department of Chemistry and Biological Science, Faculty of Science and Engineering, Aoyama Gakuin University 2 Research Center for Environmental Risk, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan

1

Toluene, a volatile organic compound with a wide range of industrial applications, can exert neurotoxic and immunotoxic effects. However, the effects of toluene exposure on developmental neuroimmunotoxicity have not yet been characterized. The present study investigated the window of susceptibility

Diphenlyarsinic acid (DPAA) was detected in the well water in Kamisu, Ibaraki, Japan in 2003, which was released accidentally from a wasted concrete lump in underground. Some individuals drinking DPAA-containing water in this area complained of cerebellar symptom and showed low cerebellar blood flow. Here we investigated the effect of DPAA exposure on primary cultured cerebellar cells from neonatal Wistar rats. Exposure