Biomedical subjects

Junjie Yao

Publications and source records attributed to Junjie Yao.

4 recordsLinked to original sources

PubMed2006

Reduced coenzyme Q10 supplementation decelerates senescence in SAMP1 mice.

The SAMP1 strain is a mouse model for accelerated senescence and severe senile amyloidosis. We determined whether supplementation with coenzyme Q10 (CoQ10) could decelerate aging in SAMP1 mice and its potential role in aging. Plasma concentrations of CoQ10 and CoQ9 decreased with age in SAMP1 but not in SAMR1 mice. Supplementation with reduced CoQ10 (CoQH2, 250 mg/kg/day) for one week increased plasma CoQ10 concentrations, with an accompanying decrease in plasma CoQ9 concentrations. In two series of experiments, lifelong supplementation with CoQH2 decreased the senescence grading scores from 10 to 14 months, 7 to 15 months, and at 17 months of age. The body weight of female mice increased from 2 to 10 months of age versus controls in the second series of experiments. Lifelong CoQH2 supplementation did not prolong or shorten the lifespan, nor did it alter the murine senile amyloid (AApoAII) deposition rate or cancer incidence. In the second series of experiments, urinary levels of 8-hydroxydeoxyguanosine did not change with age or long-term supplementation with CoQH2. Urinary levels of acrolein (ACR)-lysine adduct increased significantly with age in SAMP1 mice; however, CoQH2 had no effect. Thus, lifelong dietary supplementation with CoQH2 decreased the degree of senescence in middle-aged SAMP1 mice.

Aging, Premature↗

PubMed2004

Mouse testis transcriptome revealed using serial analysis of gene expression.

We applied serial analysis of gene expression (SAGE) to the mouse testis to reveal the global gene expression profile and to identify senescence-dependent changes in that profile. A total of 61,929 SAGE tags, including 19,323 unique tags, were obtained from 3- and 29-month-old BDF1 mice and 14-month-old SAMP1 mice. Genes highly expressed in the testis included those associated with spermatogenesis, protein metabolism, energy metabolism, growth and differentiation, and signal transduction. Testes from old mice of both strains appeared atrophied. Morphological examination of aged testes revealed extremely thin seminiferous epithelia and significantly decreased numbers of spermatids and spermatocytes. Despite the physical deterioration, no gross changes in the gene expression profile were apparent in the testes of old BDF1 mice. However, in 14-month-old SAMP1 mice, protamine 2 gene transcription was approximately 50% lower than in BDF1 mice. This reduction may be associated with the oligozoospermia and early decline in reproductive performance of SAMP1 mice. Our SAGE results are the first quantitative gene expression profile of the mouse testis and provide a reliable transcriptome reference for this organ.

Age Factors↗

PubMed2003

Amyloidosis modifier genes in the less amyloidogenic a/j mouse strain.

Apolipoprotein A-II is deposited as an amyloid fibril in aged mice (senile AApoAII amyloidosis). Although mouse strains with the apolipoprotein A-II c allele (Apoa2(c)) generally develop early-onset and severe senile amyloidosis, the A/J strain shows significantly less amyloid deposition. To identify genes that modify spontaneous amyloidosis development in the A/J mouse, we performed a genome-wide screening using hybrid mice derived from A/J and SAMP1 mice, which have Apoa2(c) and age-associated severe amyloid deposition. Our genetic analysis revealed that the lower levels of amyloidosis in the A/J strain were polygenically controlled. We found two chromosome locations associated with amyloidosis. One of these regions was in the chromosome 19 telomeric region, where the A/J alleles modify amyloidosis in an additive manner. The second region was in the chromosome 4 telomeric region, where the A/J alleles modify amyloidosis in a dominant manner. Perlecan and group II secretory phospholipase A2, located on the significantly linked region of chromosome 4, were compared in this study. These findings are for understanding the genetic mechanism of amyloidosis-related diseases and their prevention.

Amyloid↗

PubMed2002

Induction of protein conformational change in mouse senile amyloidosis.

Aggregated amyloid fibrils can induce further polymerization of precursor proteins in vitro, thus providing a possible basis for propagation or transmission in the pathogenesis of amyloidoses. Previously, we postulated that the transmission of amyloid fibrils induces conformational changes of endogenous amyloid protein in mouse senile amyloidosis (Xing, Y., Nakamura, A., Chiba, T., Kogishi, K., Matsushita, T., Fu, L., Guo Z., Hosokawa, M., Mori, M., and Higuchi, K. (2001) Lab. Invest. 81, 493-499). To further characterize this transmissibility, we injected amyloid fibrils (AApoAII(C)) of amyloidogenic C type apolipoprotein A-II (APOAIIC) intravenously into 2-month-old SAMR1 mice, which have B type apolipoprotein A-II (APOAIIB), and develop few if any amyloid deposits spontaneously. 10 months after amyloid injection, deposits were detected in the tongue, stomach, intestine, lungs, heart, liver, and kidneys. The intensity of deposition increased thereafter, whereas no amyloid was detected in distilled water-injected SAMR1 mice, even after 20 months. The deposited amyloid was composed of endogenous APOAIIB with a different amyloid fibril conformation. The injection of these amyloid fibrils of APOAIIB (AApoAII(B)) induced earlier and more severe amyloidosis in SAMR1 mice than the injection of AApoAII(C) amyloid fibrils. Thus, AApoAII(C) from amyloidogenic mice could induce a conformational change of less amyloidogenic APOAIIB to a different amyloid fibril structure, which could also induce amyloidosis in the less amyloidogenic strain. These results provide important insights into the pathogenesis of amyloid diseases.

Amyloid↗