Human Semenogelin 1 Promotes Sperm Survival in the Mouse Female Reproductive Tract.

Semenogelin 1 (SEMG1), a main component of human seminal plasma, is a multi-functional protein involved in the regulation of sperm motility and fertility. SEMG1 is orthologous to mouse seminal vesicle secretion 2 (SVS2), required for sperm survival in the female reproductive tract after copulation; however, its in vivo function remains unclear. In this study, we addressed this issue by examining the effect of recombinant SEMG1 on intrauterine mouse sperm survival. SEMG1 caused a dose-dependent decrease in mouse sperm motility, similar to its effect on human sperm, but SVS2 had no effect on mouse sperm motility. Mouse epididymal sperm in the presence of 100 µM SEMG1, a concentration that does not affect mouse sperm motility, were injected into the mouse uterus (intrauterine insemination, IUI). IUI combined with SEMG1 significantly increased the survival rate of intrauterine mouse sperm. The effect of SEMG1 on intrauterine sperm survival was comparable with that of SVS2. For clinical applications, three potentially sperm-protecting polypeptides that are easy to handle were designed from SEMG1, but their individual use was unable to mimic the ability of SEMG1. Our results indicate that SEMG1 has potential clinical applications for effective IUI and thereby for safe, simple, and effective internal fertilization.

The Basic Helix-Loop-Helix Transcription Factor GubHLH3 Positively Regulates Soyasaponin Biosynthetic Genes in Glycyrrhiza uralensis.

Glycyrrhiza uralensis (licorice) is a widely used medicinal plant belonging to the Fabaceae. Its main active component, glycyrrhizin, is an oleanane-type triterpenoid saponin widely used as a medicine and as a natural sweetener. Licorice also produces other triterpenoids, including soyasaponins. Recent studies have revealed various oxidosqualene cyclases and cytochrome P450 monooxygenases (P450s) required for the biosynthesis of triterpenoids in licorice. Of these enzymes, ß-amyrin synthase (bAS) and ß-amyrin C-24 hydroxylase (CYP93E3) are involved in the biosynthesis of soyasapogenol B (an aglycone of soyasaponins) from 2,3-oxidosqualene. Although these biosynthetic enzyme genes are known to be temporally and spatially expressed in licorice, the regulatory mechanisms underlying their expression remain unknown. Here, we identified a basic helix-loop-helix (bHLH) transcription factor, GubHLH3, that positively regulates the expression of soyasaponin biosynthetic genes. GubHLH3 preferentially activates transcription from promoters of CYP93E3 and CYP72A566, the second P450 gene newly identified and shown to be responsible for C-22ß hydroxylation in soyasapogenol B biosynthesis, in transient co-transfection assays of promoter-reporter constructs and transcription factors. Overexpression of GubHLH3 in transgenic hairy roots of G. uralensis enhanced the expression levels of bAS, CYP93E3 and CYP72A566. Moreover, soyasapogenol B and sophoradiol (22ß-hydroxy-ß-amyrin), an intermediate between ß-amyrin and soyasapogenol B, were increased in transgenic hairy root lines overexpressing GubHLH3. We found that soyasaponin biosynthetic genes and GubHLH3 were co-ordinately up-regulated by methyl jasmonate (MeJA). These results suggest that GubHLH3 regulates MeJA-responsive expression of soyasaponin biosynthetic genes in G. uralensis. The regulatory mechanisms of triterpenoid biosynthesis in legumes are compared and discussed.

Suppressive Role of Lactoferrin in Overweight-Related Female Fertility Problems.

The secretory glycoprotein lactoferrin (LF) is suggested to ameliorate overweight regardless of non-genetic or genetic mechanisms. Although maternal overweight represents a key predictor of offspring growth, the efficacy of LF on fertility problems in overweight and obese mothers remains unknown. To address this issue, we examined the effect of LF ingestion by analyzing overweight mice (Institute of Cancer Research (ICR) mice with high-fat diets; HF mice) and obese mice (leptin-deficient mice with type II diabetes; ob/ob mice). Plasma insulin, leptin, glucose, and cholesterol levels were measured, and thermal imaging and histological analysis were employed. The litter size of HF females was reduced due to miscarriage, which was reversed by LF ingestion. In addition, LF ingestion suppressed overweight prevalence in their offspring. The component analysis of the maternal blood demonstrated that glucose concentration in both HF females and their offspring was normalized by LF ingestion, which further standardized the concentration of insulin, but not leptin. LF ingestion was unable to reverse female infertility in ob/ob mice, although their obesity and uterine function were partially improved. Our results indicate that LF upregulates female fertility by reinforcing ovarian and uterine functions in females that are overweight due to caloric surplus.

Amyloid-ß oligomers suppress subunit-specific glutamate receptor increase during LTP.

INTRODUCTION: Amyloid-ß oligomers (AßOs) are assumed to impair the ability of learning and memory by suppressing the induction of synaptic plasticity, such as long-term potentiation (LTP) in the early stage of Alzheimer's disease. However, the direct molecular mechanism of how AßOs affect excitatory synaptic plasticity remains to be elucidated. METHODS: In order to study the effects of AßOs on LTP-associated changes of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)-type glutamate receptor (AMPAR) movement, we performed live-cell imaging of fluorescently labeled AMPAR subunit GluA1 or GluA2 with total internal reflection fluorescence microscopy. RESULTS: Incubation of cultured hippocampal neurons with AßOs for 1-2 days inhibited the increase in GluA1 number and GluA1 exocytosis frequency in both postsynaptic and extrasynaptic membranes during LTP. In contrast, AßOs did not inhibit the increase in GluA2 number or exocytosis frequency. DISCUSSION: These results suggest that AßOs primarily inhibit the increase in the number of GluA1 homomers and suppress hippocampal LTP expression.