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1.  Thioredoxin 1 Overexpression Extends Mainly the Earlier Part of Life Span in Mice 
We examined the effects of increased levels of thioredoxin 1 (Trx1) on resistance to oxidative stress and aging in transgenic mice overexpressing Trx1 [Tg(TRX1)+/0]. The Tg(TRX1)+/0 mice showed significantly higher Trx1 protein levels in all the tissues examined compared with the wild-type littermates. Oxidative damage to proteins and levels of lipid peroxidation were significantly lower in the livers of Tg(TRX1)+/0 mice compared with wild-type littermates. The survival study demonstrated that male Tg(TRX1)+/0 mice significantly extended the earlier part of life span compared with wild-type littermates, but no significant life extension was observed in females. Neither male nor female Tg(TRX1)+/0 mice showed changes in maximum life span. Our findings suggested that the increased levels of Trx1 in the Tg(TRX1)+/0 mice were correlated to increased resistance to oxidative stress, which could be beneficial in the earlier part of life span but not the maximum life span in the C57BL/6 mice.
doi:10.1093/gerona/glr125
PMCID: PMC3210956  PMID: 21873593
Thioredoxin; Transgenic mouse; Oxidative stress; Protein carbonylation; Aging
2.  Abnormal Post-Translational and Extracellular Processing of Brevican in Plaque-Bearing Mice Overexpressing APPsw 
Journal of neurochemistry  2010;113(3):784-795.
Aggregation of amyloid-β in the forebrain of Alzheimer's disease subjects may disturb the molecular organization of the extracellular microenvironment that modulates neural and synaptic plasticity. Proteoglycans are major components of this extracellular environment. To test the hypothesis that amyloid-β, or another amyloid precursor protein dependent mechanism modifies the accumulation and/or turnover of extracellular proteoglycans, we examined whether the expression and processing of brevican, an abundant extracellular, chondroitin sulfate-bearing proteoglycan, were altered in brains of amyloid-β-depositing transgenic mice (APPsw) as a model of Alzheimer's disease. The molecular size of chondroitin sulfate chains attached to brevican was smaller in hippocampal tissue from APPsw mice bearing amyloid-β deposits compared to non-transgenic mice, likely due to changes in the chondroitin sulfate chains. Also, the abundance of the major proteolytic fragment of brevican was markedly diminished in extracts from several telencephalic regions of APPsw mice compared to non-transgenic mice, yet these immunoreactive fragments appeared to accumulate adjacent to the plaque edge. These results suggest that amyloid-β or amyloid precursor protein exert inhibitory effects on proteolytic cleavage mechanisms responsible for synthesis and turnover of proteoglycans. Since proteoglycans stabilize synaptic structure and inhibit molecular plasticity, defective brevican processing observed in amyloid-β-bearing mice and potentially end-stage human Alzheimer's disease, may contribute to deficient neural plasticity.
doi:10.1111/j.1471-4159.2010.06647.x
PMCID: PMC2855738  PMID: 20180882
amyloid β protein; chondroitin sulfate; proteoglycan; Alzheimer's disease; matrix metalloproteinase (MMP); a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)
3.  The anti-tumor effects of calorie restriction are correlated with reduced oxidative stress in ENU-induced gliomas 
Pathobiology of Aging & Age Related Diseases  2011;1:10.3402/pba.v1i0.7189.
The anti-tumor effects of calorie restriction (CR) and the possible underlying mechanisms were investigated using ethylnitrosourea (ENU)-induced glioma in rats. ENU was given transplacentally at gestational day 15, and male offspring were used in this experiment. The brain from 4-, 6-, and 8-month-old rats fed either ad libitum (AL) or calorie-restricted diets (40% restriction of total calories compared to AL rats) was studied. Tumor burden was assessed by comparing the number and size of gliomas present in sections of the brain. Immunohistochemical analysis was used to document lipid peroxidation [4-hydroxy-2-nonenal (HNE) and malondialdehyde (MDA)], protein oxidation (nitrotyrosine), glycation and AGE formation [methylglyoxal (MG) and carboxymethyllysine (CML)], cell proliferation activity [proliferating cell nuclear antigen (PCNA)], cell death [single-stranded DNA (ssDNA)], presence of thioredoxin 1 (Trx1), and presence of heme oxygenase-1 (HO-1) associated with the development of gliomas. The results showed that the number of gliomas did not change with age in the AL groups; however, the average size of the gliomas was significantly larger in the 8-month-old group compared to that of the younger groups. Immunopositivity was observed mainly in tumor cells and reactive astrocytes in all histological types of ENU-induced glioma. Immunopositive areas for HNE, MDA, nitrotyrosine, MG, CML, HO-1, and Trx1 increased with the growth of gliomas. The CR group showed both reduced number and size of gliomas, and tumors exhibited less accumulation of oxidative damage, decreased formation of glycated end products, and a decreased presence of HO-1 and Trx1 compared to the AL group. Furthermore, gliomas of the CR group showed less PCNA positive and more ssDNA positive cells, which are correlated to the retarded growth of tumors. Interestingly, we also discovered that the anti-tumor effects of CR were associated with decreased hypoxia-inducible factor-1α (HIF-1α) levels in normal brain tissue. Our results are very exciting because they not only demonstrate the anti-tumor effects of CR in gliomas, but also indicate the possible underlying mechanisms, i.e. anti-tumor effects of CR observed in this investigation are associated with reduced accumulation of oxidative damage, decreased formation of glycated end products, decreased presence of HO-1 and Trx1, reduced cell proliferation and increased apoptosis, and decreased levels of HIF-1α.
doi:10.3402/pba.v1i0.7189
PMCID: PMC3417672  PMID: 22953030
calorie restriction; ethylnitrosourea; glioma; oxidative stress; HIF-1α
4.  Reduced Incidence and Delayed Occurrence of Fatal Neoplastic Diseases in Growth Hormone Receptor/Binding Protein Knockout Mice 
Although studies of Ames and Snell dwarf mice have suggested possible important roles of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in aging and age-related diseases, the results cannot rule out the possibility of other hormonal changes playing an important role in the life extension exhibited by these dwarf mice. Therefore, growth hormone receptor/binding protein (GHR/BP) knockout (KO) mice would be valuable animals to directly assess the roles of somatotropic axis in aging and age-related diseases because the primary hormonal change is due to GH/IGF-1 deficiency. Our pathological findings showed GHR/BP KO mice to have a lower incidence and delayed occurrence of fatal neoplastic lesions compared with their wild-type littermates. These changes of fatal neoplasms are similar to the effects observed with calorie restriction and therefore could possibly be a major contributing factor to the extended life span observed in the GHR/BP KO mice.
doi:10.1093/gerona/glp017
PMCID: PMC2667132  PMID: 19228785
Growth hormone receptor/binding protein; Knockout mouse; Neoplastic disease; Aging
5.  Do long-lived mutant and calorie-restricted mice share common anti-aging mechanisms?—a pathological point of view 
Age  2006;28(2):163-171.
Rodent models are an invaluable resource for studying the mechanism of mammalian aging. In recent years, the availability of transgenic and knockout mouse models has facilitated the study of potential mechanisms of aging. Since 1996, aging studies with several long-lived mutant mice have been conducted. Studies with the long-lived mutant mice, Ames and Snell dwarf, and growth hormone receptor/binding protein knockout mice, are currently providing important clues regarding the role of the growth hormone/insulin like growth factor-1 axis in the aging process. Interestingly, these studies demonstrate that these long-lived mutant mice have physiological characteristics that are similar to the effects of calorie restriction, which has been the most effective experimental manipulation capable of extending lifespan in various species. However, a question remains to be answered: do these long-lived mutant and calorie-restricted mice extend their lifespan through a common underlying mechanism?
doi:10.1007/s11357-006-9007-7
PMCID: PMC2464730  PMID: 19943137
aging; growth hormone receptor/binding protein; knockout mouse; neoplastic disease

Results 1-5 (5)