Morris Water Maze Test for Learning and Memory Deficits in Alzheimer's Disease Model Mice

The Morris Water Maze (MWM) was first established by neuroscientist Richard G. Morris in 1981 in order to test hippocampal-dependent learning, including acquisition of spatial memoryand long-term spatial memory 1. The MWM is a relatively simple procedure typically consisting of six day trials, the main advantage being the differentiation between the spatial (hidden-platform) and non-spatial (visible platform) conditions 2-4. In addition, the MWM testing environment reduces odor trail interference 5. This has led the task to be used extensively in the study of the neurobiology and neuropharmacology of spatial learning and memory. The MWM plays an important role in the validation of rodent models for neurocognitive disorders such as Alzheimer’s Disease 6, 7. In this protocol we discussed the typical procedure of MWM for testing learning and memory and data analysis commonly used in Alzheimer’s disease transgenic model mice

TMP21 in Alzheimer's disease : biochemical and behavioural characterization of TMP21

Alzheimer's disease (AD) is the most common neurodegenerative disorder leading to dementia. The two major neuropathological hallmarks of AD are the deposition of amyloid-b (Ab) protein in neuritic plaques and the formation of neuro brillary tangles. Ab is generated from a larger Ab recursor protein (APP) following sequential cleavage by b- and g-secretase. APP can also be cleaved in a non-amyloidogenic pathway following sequential cleavage by a- and g-secretase. In addition to the pathogenic processing of APP, the g-secretase complex also cleaves a protein called Notch, which is essential for embryonic development and may be involved in learning and memory. Transmembrane emp24-like trafficking protein 10 (TMP21) is a 21 kDa transmembrane protein involved in vesicular trafficking. Ubiquitously expressed, particularly in the plasma membrane, endoplasmic reticulum, and Golgi, TMP is vital to development, and homozygous knockout mice are embryonic lethal. Recently, TMP21 was found to play a second, pivotal role as a regulatory member of the g-secretase complex involved in AD pathogenesis. Knockdown of TMP21 increased Ab production without affecting Notch cleavage, making it a seductive target for AD research (Chen et al., 2006). This thesis shows that, similar to other members of the g-secretase complex, TMP21 is also degraded by the ubiquitin-proteasome pathway, as treatment with proteasomal inhibitors increased TMP21 protein levels in both a time- and dose-dependent manner. Furthermore, overexpression of TMP21 shifted APP processing from the a-secretase to b-secretase pathway in cell culture, and b-secretase and TMP21 could coimmunoprecipitate. This suggests that TMP21 may not only a ffect AD pathogenesis through its modulatory role on g-secretase or its trafficking of APP (Vetrivel et al., 2007), but also through its influence on b-secretase, providing a novel enzymatic target for future study. Finally, this work presents the only in vivo study of the behavioural consequences of TMP21 suppression. Motor function, anxiety, and learning and memory were examined using a comprehensive test battery. Mice heterozygous for TMP21 were found to have slightly enhanced physical abilities, increased anxiety, and potential anxiety-augmented de ficits in hippocampal learning and memory. This data will prove vital when examining future work regarding TMP21 suppression in a mouse model of AD.Medicine, Faculty ofGraduat

Transcriptional Regulation of TMP21 by NFAT

Abstract Background TMP21 is a member of the p24 cargo protein family, which is involved in protein transport between the Golgi apparatus and ER. Alzheimer's Disease (AD) is the most common neurodegenerative disorder leading to dementia and deposition of amyloid β protein (Aβ) is the pathological feature of AD pathogenesis. Knockdown of TMP21 expression by siRNA causes a sharp increase in Aβ production; however the underlying mechanism by which TMP21 regulates Aβ generation is unknown, and human TMP21 gene expression regulation has not yet been studied. Results In this report we have cloned a 3.3-kb fragment upstream of the human TMP21 gene. The transcription start site (TSS) of the human TMP21 gene was identified. A series of nested deletions of the 5' flanking region of the human TMP21 gene were subcloned into the pGL3-basic luciferase reporter plasmid. We identified the -120 to +2 region as containing the minimal sequence necessary for TMP21 gene promoter activity. Gel shift assays revealed that the human TMP21 gene promoter contains NFAT response elements. Expression of NFAT increased TMP21 gene expression and inhibition of NFAT by siRNA reduced TMP21 gene expression. Conclusion NFAT plays a very important role in the regulation of human TMP21 gene expression. This study demonstrates that the human TMP21 gene expression is transcriptionally regulated by NFAT signaling.</p

Transcriptional Regulation of TMP21 by NFAT

Background: TMP21 is a member of the p24 cargo protein family, which is involved in protein transport between the Golgi apparatus and ER. Alzheimer's Disease (AD) is the most common neurodegenerative disorder leading to dementia and deposition of amyloid β protein (Aβ) is the pathological feature of AD pathogenesis. Knockdown of TMP21 expression by siRNA causes a sharp increase in Aβ production; however the underlying mechanism by which TMP21 regulates Aβ generation is unknown, and human TMP21 gene expression regulation has not yet been studied. Results In this report we have cloned a 3.3-kb fragment upstream of the human TMP21 gene. The transcription start site (TSS) of the human TMP21 gene was identified. A series of nested deletions of the 5' flanking region of the human TMP21 gene were subcloned into the pGL3-basic luciferase reporter plasmid. We identified the -120 to +2 region as containing the minimal sequence necessary for TMP21 gene promoter activity. Gel shift assays revealed that the human TMP21 gene promoter contains NFAT response elements. Expression of NFAT increased TMP21 gene expression and inhibition of NFAT by siRNA reduced TMP21 gene expression. Conclusion NFAT plays a very important role in the regulation of human TMP21 gene expression. This study demonstrates that the human TMP21 gene expression is transcriptionally regulated by NFAT signaling.Psychiatry, Department ofNon UBCMedicine, Faculty ofReviewedFacult