Identification of Igf2, Igfbp2 and Enpp2 as estrogen-responsive genes in rat hippocampus.

Estrogen has an important effect on higher brain function such as memory, learning, and emotion in which the hippocampus plays a critical role. The hippocampus expresses estrogen receptors, ER alpha and ERbeta, which are ligand-dependent transcription factors; however, the precise mechanism of estrogen action is not fully understood. We explored genes which are up-regulated by estrogen in the hippocampus using ovariectomized rat models. Microarray analysis revealed that mRNA levels of ectonucleotide pyrophosphatase/phosphodiesterase 2 (Enpp2), insulin like growth factor 2 (Igf2) and insulin-like growth factor binding protein 2 (Igfbp2) were increased by estrogen in the hippocampus. Quantitative-PCR analysis demonstrated that the levels of Enpp2, Igf2 and Igfbp2 mRNA were elevated by estrogen administration in the hippocampus but not in the hypothalamus. On the other hand, ERalpha, ERbeta and progesterone receptor (PR) mRNA expression was up-regulated by estrogen only in the hypothalamus. We further analyzed the time-dependent regulation of these genes using rat pituitary adenoma, MtT/S and GH3 cells, which are known to express ERalpha. In both MtT/S and GH3 cells, Igfbp2 and Enpp2 mRNAs were up- and down-regulated by estrogen, respectively, whereas Igf2 mRNA was increased only in GH3 cells. These results demonstrate a brain region- and cell type-specific responses to estrogen in rat brain, suggesting that Igf signaling may mediate the estrogen function in the hippocampus.

Pharmacogenetics of hormone replacement therapy for climacteric symptoms.

Hormone replacement therapy (HRT) is highly effective for women suffering from climacteric symptoms, with occasionally severe side effects. To determine which women needs HRT for climacteric symptoms indeed, pharmacogenetical approach for HRT was performed. Under the condition of minimal HRT, 33 patients required HRT for more than 1 year and the remaining 156 did not. Three single nucleotide polymorphisms (SNPs) in estrogen receptor alpha (ERalpha) gene and 3 SNPs and a microsatellite polymorphism in estrogen receptor beta (ERbeta) gene were analyzed using LightTyper and PCR. Homozygous for 18 CA repeats of D14S1026 (OR 8.00, 95% CI 2.56-25.02, P<0.001) and rs1256049 (OR 6.35, 95% CI 2.38-16.92, P=0.004) in ERbeta associated with minimal HRT. In contrast, rs1271572 in 789bp upstream region of ERbeta (OR 0.30, 95% CI 0.14-0.65, P=0.002) gene decreased HRT. rs2228480 in ERalpha gene also increased HRT. Tailored decisions can be expected on the future use of HRT referring genetic polymorphisms of individuals.

[Polymorphisms of steroid hormone receptors].

Different polymorphisms have been described in steroid hormone receptors which are related with variable human diseases. Polymorphisms of estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) are related not only with reproductive diseases, but also with osteoporosis, cardiovascular disease, malignancy such as breast cancer, and disorders involving central nervous system. They are also related with individual reactivity to medications. Polymorphisms of androgen receptor are known to be associated with prostate cancer. Polymorphisms of glucocorticoid receptor are related with severity of inflammation and allergy. Analysis of steroid hormone receptor polymorphisms will make it possible to develop tailored medicine for human diseases.

Molecular cloning and characterization of rat brain endothelial cell derived gene-1 (tumor suppressor candidate 5) expressing abundantly in adipose tissues.

We report the cloning and expressional analysis of rat brain endothelial cell derived gene-1 (BEC-1), detected as a gene dominantly expressed in rat brain endothelial cells by the use of suppression subtractive hybridization technique. The complementary deoxyribonucleic acid sequence of BEC-1 messenger ribonucleic acid was completely determined with a full length of 3410 bp. The open reading frame within the sequence consisted of 522 bp, and the predicted protein sequence was 173 amino acid residues. BEC-1 gene was thought to be rat tumor suppressor candidate 5 (TUSC5), since BEC-1 had considerable homology with both mouse TUSC5 and human located at 17-p-13 point three 1 (LOST1) categorized as human TUSC5 (identities of 97% and 85%, respectively), which were recently identified as a novel tumor suppressor gene candidate. Expressional analyses for BEC-1 mRNA with real-time PCR and of BEC-1 protein by Western blotting demonstrated that both were dominantly expressed in the adipose tissues of Sprague-Dawley (SD) rats. We analyzed and compared the differential expressions of BEC-1 (TUSC5) mRNA and protein in fat tissues between obese homozygous (fa/fa) and lean wild-type (+/+) Zucker rats. Both expressions in the epididymal white adipose tissue (WAT) were highest, followed by those in the interscapular brown adipose tissue (BAT), subcutaneous, and mesenteric WATs, respectively. Interestingly, both expressions in epididymal WAT of obese Zucker rats were significantly lower than those in lean rats. Although cold exposure at 4 degrees C for 6 h significantly stimulated uncoupling protein-1 (UCP-1) mRNA expression, it significantly inhibited BEC-1 (TUSC5) mRNA expression in the interscapular BAT. These data indicated that rat BEC-1 (TUSC5) was abundantly expressed in adipose tissues, and that it might be involved in their regulation independently of UCP-1.

Association of cytosine-adenine repeat polymorphism of the estrogen receptor-beta gene with menopausal symptoms.

BACKGROUND: The nature and severity of menopausal symptoms are highly variable among women. Polymorphisms of the estrogen receptor-beta (ERbeta) gene, such as cytosine-adenine (CA) dinucleotide repeats in intron 5, have been implicated in various diseases. OBJECTIVE: We investigated the possible role of a CA dinucleotide repeat polymorphism in intron 5 of the ERbeta gene in the occurrence of menopausal and premenstrual symptoms. METHODS: Fifty-one postmenopausal Japanese women were interviewed about premenstrual symptoms, menopausal symptoms, and use of hormone replacement therapy. Menopausal symptoms were divided into vasomotor, psychological, and musculoskeletal symptoms, and summary scores were created on the basis of severity. CA repeat polymorphism of the ERbeta gene was examined using denaturing high-performance liquid chromatography with the WAVE DNA Fragment Analysis System (Transgenomic Inc., Omaha, Nebraska). RESULTS: The number of CA repeats of the ERP gene ranged from 14 to 25, and subjects could be divided into 3 groups: those with < or =17 repeats, or extremely short (E); 18 to 21 repeats, or short (S); and > or =22 repeats, or long (L). Four genotypes of CA repeats (EL, SS, SL, and LL) were found among the subjects, with SL being the most common. Relative to subjects with the SL genotype, women with SS had a 7.0-fold increased risk of vasomotor symptoms (odds ratio [OR] = 7.0; 95% CI, 1.25-39.15; P < 0.05), a 13.0-fold higher risk of psychological symptoms (OR = 13.0; 95% CI, 1.44-117.2; P < 0.01), and a 7.6-fold increased risk of premenstrual symptoms (OR = 7.6; 95% CI, 1.61-35.9; P = 0.01). The EL genotype was associated with an increased risk of vasomotor symptoms (P < 0.05), depression (P < 0.01), and premenstrual symptoms (P < 0.01). CONCLUSIONS: CA repeat polymorphism of the ERbeta gene may be associated with menopausal and premenstrual symptoms. Premenstrual symptom scores were significantly related to menopausal symptom scores.

Analysis of genes dominantly expressed in rat cerebral endothelial cells using suppression subtractive hybridization.

In mammals, a fully developed, highly branched vascular system specialized for each particular organ or tissue is essential for obtaining metabolic nutrients supply. The formation of a blood-brain barrier that protects against environmental insults is a distinguishing feature of the brain's vascular system. Since this is accomplished by cerebral endothelial cells (CECs), we analyzed the genes specifically and/or dominantly expressed in rat CECs using Suppression Subtractive Hybridization (SSH). We found 39 genes specifically and/or dominantly expressed in CECs. 24 genes of known function (thrombospondin-2, vimentin, etc.), 13 genes of known sequence but unknown function including 7 of ESTs (SNERG1, rat GPCR, etc.), and 2 novel genes. The physiological significance of these genes in CECs has been under investigation. SSH is useful for identifying genes regulated in an organ-specific manner in cells such as CECs to obtain clarification of their physiological roles.

Effect of fenofibrate on uric acid metabolism in Japanese hyperlipidemic patients.

Forty Type IIb or IV hyperlipidemic patients (serum triglyceride concentrations were higher than 150 mg/dl) were treated with fenofibrate (300 mg/day) for 12 weeks. Lipid profile and uric acid metabolism were evaluated before and after the treatment; the serum concentrations of total cholesterol and triglyceride respectively decreased from 224 +/- 41.9 mg/dl to 199 +/- 35.2 mg/dl and from 205 +/- 71.7 mg/dl to 134 +/- 67.5 mg/dl (p < 0.001). The uric acid concentrations in the serum also significantly decreased from 7.0 +/- 1.58 mg/dl to 5.2 +/- 1.57 mg/dl (p < 0.001). Fenofibrate treatment did not cause any change in the serum xanthine and hypoxanthine concentrations. Instead the urinary concentrations of uric acid decreased from 7.0 +/- 1.58 mg/dl to 5.2 +/- 1.57 mg/dl (p < 0.01), while the clearance ratio of uric acid and creatinin increased from 6.1 +/- 2.56 to 9.9 +/- 3.87 (p = 0.02) by the fenofibrate treatment. Fenofibrate decreases uric acid concentrations in the serum not as a result of inhibition of uric acid production but by increasing the urinary excretion of uric acid.

Rat cerebral endothelial cells express trk C and are regulated by neurotrophin-3.

Cerebral endothelial cells (CEC) are critical for formation of the vascular system in the mammalian central nervous system (CNS). We focused on the neurotrophin (NT) for its possible involvement in signaling for the regulation of CEC to control formation and maintenance of the vascular system in CNS in comparison of rat cerebral endothelial cells (RCEC) with rat aortic endothelial cells (RAEC). We found that (1) trk C, a receptor for neurotrophin-3 (NT-3), is dominantly expressed in RCEC, but trk B, a receptor for brain-derived neurotrophic factor, is dominantly expressed in RAEC; (2) NT-3 inhibited the proliferation of RCEC; and (3) NT-3 stimulated the production of nitric oxide (NO) with increases in protein expression of endothelial NO synthase. These data indicated that NT may regulate and/or maintain the functions of the brain microvasculature through the regulation of CEC.