Sun Bo Shim

Green tea catechin leads to global improvement among Alzheimer's disease-related phenotypes in NSE/hAPP-C105 Tg mice

Amyloid β (Αβ) has been reported to be responsible for the functional and structural abnormalities of Alzheimers disease (AD) through the induction of oxidative stress. The aim of this study was to determine whether or not treatment of transgenic (Tg) mice with green tea catechin (GTC), a radical scavenger, improves AD phenotypes. To test this, 7-month-old Tg mice were treated with a low (1 mg) or high (10 mg) dose of GTC for 6 months. Surprisingly, GTC-treated Tg mice exhibited significant decreases in behavioral impairment, Aβ-42 production, APP-C99/89 expression, γ-secretase component and Wnt protein levels, γ-secretase activity and MAPK activation. In contrast, the levels of APP-C83 protein and enzyme activities (α-secretase, neprilysin and Pin1) were elevated in the GTC-treated groups. Moreover, GTC-treated groups showed lower levels of total cholesterol and low-density lipoprotein cholesterol, whereas the level of high-density lipoprotein cholesterol increased. These results provide the first experimental evidence that GTC improves AD phenotypes, thereby suggesting that GTC can be used in the prevention of AD or treatment of AD patients.

Detection of Allergenic Compounds Using an IL-4/Luciferase/CNS-1 Transgenic Mice Model

The interleukin-4 (IL-4) signaling cascade has been identified as a potentially important pathway in the development of allergies. The principal objective of this study was to produce novel transgenic (Tg) mice harboring the luciferase gene under the control of the human IL-4 promoter and the enhancer of IL-4 (CNS-1), in an effort to evaluate three types of allergens including a respiratory sensitizer, vaccine additives, and crude extracts of natural allergens in vivo. A new lineage of Tg mice was generated by the microinjection of pIL-4/Luc/CNS-1 constructs into a fertilized mice egg. The luciferase activity was successfully regulated by the IL-4 promoter in splenocytes cultured from IL-4/Luc/CNS-1 Tg mice. From the first five founder lines, one (#57) evidencing a profound response to ovalbumin was selected for use in evaluating the allergens. Additionally, the lungs, thymus, and lymph nodes of IL-4/Luc/CNS-1 Tg mice evidenced high luciferase activity in response to allergens such as phthalic anhydride (PA), trimellitic anhydride, ovalbumin, gelatin, Dermatophagoides pteronyssinus extracts, and Japanese cedar pollen, whereas key allergy-related indicators including ear thickness, Immunoglobulin E concentration, and the infiltration of inflammatory leukocytes in response to PA were unaltered in the Tg mice relative to the non-Tg mice. Furthermore, the expression levels of endogenous type 2 helper T cells cytokines and proinflammatory cytokines were similarly increased in these organs of IL-4/Luc/CNS-1 Tg mice in response to allergens. These results indicate that IL-4/Luc/CNS-1 Tg mice may be used as an animal model for the evaluation and prediction of the human body response to a variety of allergens originating from the environment and from certain industrial products.

The effects of long-duration, low-temperature ground transportation on physiological and biochemical indicators of stress in mice.

Transportation can cause stress to laboratory animals and alter physiological characteristics that may confound experimental results. The authors investigated stress-related effects of 3–4 h of transportation by truck in two strains of mice (C57BL/6, which are known to be aggressive, and ICR, which are less aggressive). Transported mice had sufficient space and access to water, though temperature in the truck was lower than what is usually recommended. Transportation affected the following parameters in both strains of mice: (i) serum corticosterone concentrations, (ii) expression of the chaperone proteins Hsp70 and Grp78 in various tissues and (iii) concentrations of serological enzymes that are associated with liver disease. These parameters also differed substantially between the two strains of mice.

Overexpression of Insulin Degrading Enzyme could Greatly Contribute to Insulin Down-regulation Induced by Short-Term Swimming Exercise.

Exercise training is highly correlated with the reduced glucose-stimulated insulin secretion (GSIS), although it enhanced insulin sensitivity, glucose uptake and glucose transporter expression to reduce severity of diabetic symptoms. This study investigated the impact of short-term swimming exercise on insulin regulation in the Goto-Kakizaki (GK) rat as a non-obese model of non-insulin-dependent diabetes mellitus. Wistar (W/S) and GK rats were trained 2 hours daily with the swimming exercise for 4 weeks, and then the changes in the metabolism of insulin and glucose were assessed. Body weight was markedly decreased in the exercised GK rats compare to their non-exercised counterpart, while W/S rats did not show any exercise-related changes. Glucose concentration was not changed by exercise, although impaired glucose tolerance was improved in GK rats 120 min after glucose injection. However, insulin concentration was decreased by swimming exercise as in the decrease of GSIS after running exercise. To identify the other cause for exercise-induced insulin down-regulation, the changes in the levels of key factors involved in insulin production (C-peptide) and clearance (insulin-degrading enzyme; IDE) were measured in W/S and GK rats. The C-peptide level was maintained while IDE expression increased markedly. Therefore, these results showed that insulin down-regulation induced by short-term swimming exercise likely attributes to enhanced insulin clearance via IDE over-expression than by altered insulin production.

Pen-2 overexpression induces Aβ-42 production, memory defect, motor activity enhancement and feeding behavior dysfunction in NSE/Pen-2 transgenic mice

Pen-2 is a key regulator of the γ-secretase complex, which is involved in the production of the amyloid β (Aβ)-42 peptides, which ultimately lead to Alzheimers disease (AD). While Pen-2 has been studied in vitro, Pen-2 function in vivo in the brains of transgenic (Tg) mice overexpressing human Pen-2 (hPen-2) protein has not been studied. This study aimed to determine whether Pen-2 overexpression could regulate the AD-like phenotypes in Tg mice. NSE/hPen-2 Tg mice were produced by the microinjection of the NSE/hPen-2 gene into the pronucleus of fertilized eggs. The expression of the hPen-2 gene under the control of the NSE promoter was successfully detected only in the brain and kidney tissue of NSE/hPen-2 Tg mice. Also, 12-month-old NSE/hPen-2 Tg mice displayed behavioral dysfunction in the water maze test, motor activity and feeding behavior dysfunction in food intake/water intake/motor activity monitoring system. In addition, tissue samples displayed dense staining with antibody to the Aβ-42 peptide. Furthermore, NSE/hPen-2 Tg mice exhibiting feeding behavior dysfunction were significantly more apt to display symptoms related to diabetes and obesity. These results suggest that Pen-2 overexpression in NSE/hPen-2 Tg mice may induce all the AD-like phenotypes, including behavioral deficits, motor activity and feeding behavior dysfunction, Aβ-42 peptide deposition and chronic disease induction.

GATA binding protein 3 overexpression and suppression significantly contribute to the regulation of allergic skin inflammation.

GATA binding protein 3 (GATA3) is a key molecule regulating the balance in the ratio of type 1 helper T (Th1) cells to type 2 helper T (Th2) cells, which is thought to be indicative of the pathogenesis of allergic diseases such as asthma and atopic dermatitis. The aim of this study was to investigate the role of GATA3 in allergic skin inflammation. Transgenic (Tg) mice overexpressing human GATA3 (hGATA3) were produced by the microinjection of pCMV/hGATA3 constructs into fertilized mouse eggs. The hGATA3 gene was successfully expressed at the protein level in the lymph node and thymus of CMV/hGATA3 transfected cells and Tg mice. CMV/hGATA3 Tg mice showed a significant increase in the allergic skin inflammation response such as ear thickness, draining auricular lymph node (aLN) weight, epidermal thickness, inflammatory cell number and Th2 immunoglobulin (Ig) concentration compared to wild-type (WT) mice after phthalic anhydride (PA) treatment. Furthermore, the secretion of Th2 type cytokines was increased by PA treatment in CMV/hGATA3 Tg mice, while the secretion of Th1 type cytokine was suppressed under the same conditions. However, the increased levels of Th2 type cytokines in CMV/hGATA3 Tg mice were almost recovered by the down-regulation of GATA3 expression with D-pinitol treatment. Therefore, these findings suggest that GATA3 could be considered as a potential target regulating the mechanism responsible for the differences in allergic skin inflammation.

Proteomic analysis of kidneys from selenoprotein M transgenic rats in response to increased bioability of selenium

BackgroundTo characterize changes in global protein expression in kidneys of transgenic rats overexpressing human selenoprotein M (SelM) in response to increased bioabivility of selenium (Sel), total proteins extracted from kidneys of 10-week-old CMV/hSelM Tg and wild-type rats were separated by 2-dimensional gel electrophoresis and measured for changes in expression.ResultsTen and three proteins showing high antioxidant enzymatic activity were up- and down-regulated, respectively, in SelM-overexpressing CMV/hSelM Tg rats compared to controls based on an arbitrary 2-fold difference. Up-regulated proteins included LAP3, BAIAP2L1, CRP2, CD73 antigen, PDGF D, KIAA143 homolog, PRPPS-AP2, ZFP313, HSP-60, and N-WASP, whereas down-regulated proteins included ALKDH3, rMCP-3, and STC-1. After Sel treatment, five of the up-regulated proteins were significantly increased in expression in wild-type rats, whereas there were no changes in CMV/hSelM Tg rats. Only two of the down-regulated proteins showed reduced expression in wild-type and Tg rats after Sel treatment.ConclusionsThese results show the primary novel biological evidences that new functional protein groups and individual proteins in kidneys of Tg rats relate to Sel biology including the response to Sel treatment and SelM expression.

Aβ-42 deposition significantly increases the insolubility of synaptophysin in the brains of hAPPsw/hPS2m double transgenic mice

Synaptophysin is a synaptic vesicle glycoprotein involved in the regulation process for neurotransmitter release, which is distributed throughout neuroendocrine cells and all neurons in the brain and spinal cord. In an effort to determine whether amyloid β (Aβ)-42 peptides could influence the quantity and biochemical properties of synaptophysin, alterations in the levels of the synaptophysin protein in various soluble fractions were detected in the brains of four genotypes of transgenic mice (Tg) including Non-Tg, neuron-specific enolase (NSE)-hPS2m, NSE-hAPPsw and hAPPsw/hPS2m double Tg mice. Among the four genotypes of Tg mice, the highest levels of Aβ-42 peptides were noted in hAPPsw/hPS2m, followed by NSE-hAPPsw, NSE-hPS2m and Non-Tg mice. In the brains of these mice displaying different levels of Aβ-42 peptides, the levels of soluble synaptophysin were reduced significantly only in the hAPPsw/hPS2m double Tg mice compared to the Non-Tg mice. However, immunohistochemical analysis revealed no differences in the levels of total synaptophysin protein between the neocortex and hippocampus of the four different genotypes of mice. Western blot analysis using four-step fractions with differing solubility revealed a marked decrease in synaptophysin levels in the Tris-buffer saline fraction of hAPPsw/hPS2m double Tg mice and a significant increase in the formic acid fraction, relative to the Non-Tg mice. The results obtained from our in vivo experiments in mice are identical to the results observed in SK-N-MC cells treated with 100 nM Aβ-42 peptides. Therefore, our experiments collectively suggest that Aβ-42 peptides may alter the solubility without changing the total amount of synaptophysin.