Yasuko Yamamoto

Successful completion of daily activities relies on the ability to select the relevant features of the environment for memory and recall. Disruption to these processes can lead to various disorders, such as attention-deficit hyperactivity disorder (ADHD). Dopamine is a neurotransmitter implicated in the regulation of several processes, including attention. In addition to the higher-order brain function, dopamine is implicated in the regulation of adult neurogenesis. Previously, we generated mice lacking Shati, an N-acetyltransferase-8-like protein on a C57BL/6J genetic background (Shati/Nat8l-/- ). These mice showed a series of changes in the dopamine system and ADHD-like behavioral phenotypes. Therefore, we hypothesized that deficiency of Shati/Nat8l would affect neurogenesis and attentional behavior in mice. We found aberrant morphology of neurons and impaired neurogenesis in the dentate gyrus of Shati/Nat8l-/- mice. Additionally, research has suggested that impaired neurogenesis might be because of the reduction of dopamine in the hippocampus. Galantamine (GAL) attenuated the attentional impairment observed in the object-based attention test via increasing the dopamine release in the hippocampus of Shati/Nat8l-/- mice. The α7 nicotinic acetylcholine receptor antagonist, methyllycaconitine, and dopamine D1 receptor antagonist, SCH23390, blocked the ameliorating effect of GAL on attentional impairment in Shati/Nat8l-/- mice. These results suggest that the ameliorating effect of GAL on Shati/Nat8l-/- attentional impairment is associated with activation of D1 receptors following increased dopamine release in the hippocampus via α7 nicotinic acetylcholine receptor. In summary, Shati/Nat8l is important in both morphogenesis and neurogenesis in the dentate gyrus and attention, possible via modulation of dopaminergic transmission.

Although the restricted dynamic range of conventional proteomic technology using two-dimensional gels and mass spectrometry has limited applicability (i.e. plasma proteome), our recent studies of proteomics technologies using electrophoresis to discover and identify new biomarkers are summarized. Low-abundance proteins are rarely seen on traditional two-dimensional gel electrophoresis (2-DE) analysis of plasma because of the highly abundant soluble proteins such as albumin and globulin in plasma. In this study, serum proteins can be separated into two fractions by the Con A-Sepharose column (retained fraction was enriched in N-glycosylated proteins), which is used for the exclusion of albumin and is a simple method to analyze proteins in plasma. The % area of each protein band was compared between the different groups and proteins in each band were identified using LC/MS/MS. In addition, we also summarized recent results from focused brain proteomics to identify proteins associated with dysmnesia using 2-DE. Neuronal protein expression in viral infected mice was compared with that in non-infected mice using the Image Master 2D. We detected approximately 700 protein spots, of which approximately 40 spots were distinguishable between non-infected and virus-infected mice. This proteomic analysis is a useful tool for identifying proteins in mouse diseases model (especially using KO or TG mice).<br>

Endogenous ALP activities were examined in various tissues using different substrates, Nitroblue tetrazolium chloride/ 5-brom-4-chloro-3-indolyl phosphate (NBT/BCIP), Vector Blue, and Vector Red. Comparative analysis demonstrated marked differences of signal intensities depending on the substrates. Catalyzed NBT/BCIP Products deposited heavily and proved to be sensitive for detecting signals, the Vector Blue the second, and the Vector Red less sensitive, although the three substrates yielded their own color precipitations. Endogenous ALP activities were observed in all tissues examined. The other factors such as histological procedures also affected endogenous ALP activities. Frozen tissues either fixed or unfixed exhibited well-preserved ALP activities, while the signals in paraffin-embedded materials were eliminated from most tissues, except for small intestine. An ALP inhibitor, or Levamisole, actually suppressed the enzyme activities in various tissues but not always successful nor perfect. The present study provokes cautious information necessary to control endogenous ALP activities in target tissues of interest when exogenous ALP is applied as a tool of signal detection.