The results of this study demonstrated that the isoflavones of aglycone-rich Fsoy were absorbed faster and in greater amounts than those of glucoside-rich Soy in postmenopausal Japanese women.

Sorting nexin 5 (SNX5), a member of sorting nexin family, plays an important role in membrane trafficking, including the retrograde trafficking of the cation independent mannose 6-phosphate receptor (CI-M6PR) and macropinocytosis. Using ESI-LCMS/MS analysis, we confirmed that SNX5 serine 226 is phosphorylated. Since SNX5 forms heterodimers with SNX1 or SNX2, we examined the effect of phosphorylation at S226 on the heterodimer formations. Wild-type and mutants of SNX5, in which S226 was mutated to a glutamic acid or an alanine, were expressed in 8505C cells. In pull-down assays using SNX5 as bait, only the S226E mutant failed to precipitate both SNX1 and SNX2. Confocal microscopy data indicated that the wild type and S226A mutant were colocalized with SNX1 and SNX2 in endosomes, but the S226E was not. SNX5 and SNX6 support each other's functions and are involved with CI-M6PR retrograde trafficking. In SNX5 and SNX6 double knockdown cells, CI-M6PR was dispersed and colocalized with the endosomal marker EEA1. In a rescue experiment using SNX5 mutants, the S226A rescued CI-M6PR localization, similar to control cells, but S226E did not. Furthermore, the decrease in the uptake of dextran by macropinocytosis in SNX5 knockdown cells was recovered by the expression of rescue-wild type or S226A mutant, but not by the rescue-S226E mutant. These observations indicate that SNX5 constitutive phosphorylation that mimics the mutant S226E decreases the active SNX5 in these cells. The phosphorylation of SNX5 regulates the dimerization with SNX1 or SNX2, and this suggests that it controls membrane trafficking and protein sorting.

Objective: Since soy isoflavone intake, high in Japanese and Asian populations was epidemiologically associated with lower risks of cardiovascular diseases(CVD), we focused on soy isoflavone effects on other risks of lifestyle-related diseases and investigated whether or not the intake of isoflavone aglycone-rich fermented soybeans affected bone and glucose metabolisms in post-menopausal women.Methods: Healthy post-menopausal women aged 47 to 70 years, 65 in total, were invited to a test diet-placebo independent parallel double-blind dietary intervention study, and were randomized for taking isoflavone aglycone-rich fermented soybean soup (isoflavone aglycone 24 mg/day) or placebo soup for 4 weeks. Blood and 24-hour urine samples were collected before and after the intake. We analyzed the markers of bone and glucose metabolisms. The subjects refrained from consuming other soybean-based foods and isoflavone supplements for 9 weeks, starting at 5 weeks in advance of the intervention. Results:We analyzed 56 subjects from whom complete 24-hour urine samples could be collected, and obtained the following results: 1. Urinary total isoflavone level was significantly higher at 4 weeks in the fermented soybean group (S) than that in the placebo group (P). 2. In P, the urinary excretion of deoxypyridinoline (bone resorption marker) was significantly increased at 4 weeks from the baseline value but did not show any significant change in S. In contrast the serum osteocalcin (bone formation marker) level was significantly increased at 4 weeks from the baseline value in S, but showed no significant change in P. 3. Serum insulin level was significantly lower at 4 weeks in S than in P, while blood glucose levels were similar in S and P. Thus, insulin resistance (the homeostasis model assessment of insulin resistance) was significantly lower at 4 weeks in S than in P. Conclusion:Four-week intake of fermented soybean soup containing 24 mg of isoflavone aglycone improved bone and glucose metabolisms in post-menopausal women, suggesting that the continuous intake of fermented soybeans could prevent bone loss and improve insulin resistance after menopause.