The importance of ERα and ERβ gene polymorphisms in PCOS

Estrogens act through binding to estrogen receptor α (ERα) and β (ERβ). Studies in knockout mice have shown that the absence of ERα leads to the polycystic ovary syndrome (PCOS) phenotype. Furthermore, the expression of ERβ gene is lower in follicles derived from women with PCOS compared with healthy women. The aim of this study was to investigate the importance of ERα and ERβ gene polymorphisms in PCOS. A cohort of 180 women with PCOS and 140 healthy controls were recruited, and the PvuII and XbaI polymorphisms of ERα, as well as, the AluI and RsaI polymorphisms of ERβ were genotyped. No difference was found in the distribution of these polymorphisms between patients and healthy controls. However, in PCOS women, carriers of TC and TT genotypes of PvuII polymorphism had lower fasting glucose to insulin ratio compared with carriers of CC genotype (p = 0.029). In addition, the presence of AA genotype of XbaI polymorphism was associated with lower levels of follicle-stimulating hormone (FSH) compared with the presence of AG and GG genotypes (p = 0.03). The association of ERα polymorphisms with insulin resistance indices and FSH levels emphasizes the importance of ERα as a genetic modifier of the PCOS phenotype.     

Perturbed ER homeostasis by IGF-IIRα promotes cardiac damage under stresses

The heart is a very dynamic pumping organ working perpetually to maintain a constant blood supply to the whole body to transport oxygen and nutrients. Unfortunately, it is also subjected to various stresses based on physiological or pathological conditions, particularly more vulnerable to damages caused by oxidative stress. In this study, we investigate the molecular mechanism and contribution of IGF-IIRα in endoplasmic reticulum stress induction in the heart under doxorubicin-induced cardiotoxicity. Using in vitro H9c2 cells, in vivo transgenic rat cardiac tissues, siRNAs against CHOP, chemical ER chaperone PBA, and western blot experiments, we found that IGF-IIRα overexpression enhanced ER stress markers ATF4, ATF6, IRE1α, and PERK which were further aggravated by DOX treatment. This was accompanied by a significant perturbation in stress-associated MAPKs such as p38 and JNK. Interestingly, PARKIN, a stress responsive cellular protective mediator was significantly downregulated by IGF-IIRα concomitant with decreased expression of ER chaperone GRP78. Furthermore, ER stress-associated pro-apoptotic factor CHOP was increased considerably in a dose-dependent manner followed by elevated c-caspase-12 and c-caspase-3 activities. Conversely, treatment of H9c2 cells with chemical ER chaperone PBA or siRNA against CHOP abolished the IGF-IIRα-induced ER stress responses. Altogether, these findings suggested that IGF-IIRα contributes to ER stress induction and inhibits cellular stress coping proteins while increasing pro-apoptotic factors feeding into a cardio myocyte damage program that eventually paves the way to heart failure.

     

Sex specific response of cultured human bone cells to ERα and ERβ specific agonists by modulation of cell proliferation and creatine kinase specific activity

We have previously reported that human cultured bone cells (hObs) respond to estradiol-17β (E2) by stimulating DNA synthesis, creatine kinase BB specific activity (CK) and other parameters sex-specifically. We now investigate the sex specificity of the response of these hObs to estrogen receptor (ER) α and ERβ specific agonists. Real time PCR revealed that all cells express mRNA for both ERs. ERα mRNA but not ERβ mRNA was stimulated by all estrogenic compounds in both pre- and post-menopausal hObs with no effect in male hObs. Cells treated with E2, 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN; ERβ specific agonist) and 4,4',4″-[4-propyl-(1H)-pyrazol-1,3,5-triyl] tris-phenol (PPT; ERα specific agonist) showed increased DNA synthesis and CK in all female but not male hObs. Raloxifene (Ral), a specific ERα antagonist, inhibited the stimulation of DNA synthesis and CK by E2 or PPT, but not by DPN. DPN and PPT like E2 modulated the expression of both 12 and 15 lipooxygenase (LO) mRNA in both female but not male hObs. 12 and 15 HETE production was modulated only by DPN and PPT in these cells. The LO inhibitor baicaleine inhibited only E2 and PPT but not DPN effects in both female hObs. In conclusion, we provide herein evidence for the separation of age- and sex-dependent mediation via both ERα and ERβ pathways in the effects of estrogens on hObs, with a yet unknown mechanism.     

ER subtype selectivity of m-carborane-containing phenols: C-alkyl groups on the m-carborane cage enhance ERα selectivity

Estrogen receptor (ER) exhibits two subtypes, ERα and ERβ, whose biological functions are quite different despite expression in the same tissues. We developed diiodo-m-carborane derivative 3a, which showed 14-fold selectivity for ERβ with high binding affinity toward ERβ. Interestingly, introduction of an alkyl group into the carbon atom of the m-carborane cage of 3a markedly enhanced the binding affinity toward ERα and decreased affinity toward ERβ. C-n-propyl derivative 3d showed 28-fold selectivity for ERα in an ER binding assay and promoted proliferation of MCF-7 breast cancer cells. Docking simulation studies suggest that the directions of the n-propyl group and the diiodo substituent introduced on the m-carborane cage play important roles for the control of ER subtype selectivity. As 3a and 3d showed ERβ and ERα selectivity with high binding affinity, respectively, these ligands may be useful as biological tools to aid in understanding the different roles of ER subtypes.     

Dihydroxylation of dehydroepiandrosterone in positions 7α and 15α by mycelial fungi

The ability of 485 fungal strains is studied for catalysis of the process of 7α, 15α-dihydroxylation of dehydroepiandrosterone (DHEA, 3β-hydroxy-5-androstene-17-one), a key intermediate of the synthesis of physiologically active compounds. The ability for the formation of 3β, 7α, 15α-trihydroxy-5-androstene-17-one (7α, 15α-diOH-DHEA) was found for the first time for representatives of 12 genera, eight families, and six orders of ascomycetes, eight genera, four families, and one order of zygomycetes, one genus, one family, and one order of basidiomycetes, and four genera of mitosporic fungi. The most active strains are found among genera Acremonium, Gibberella, Fusarium, and Nigrospora. In the process of transformation of DHEA (2 g/l) by strains of Fusarium oxysporum VKM F-1600 and Gibberella zeae BKM F-2600, the molar yield was 63 and 68%, respectively. Application of the revealed active strains of microorganisms opens prospects for the efficient production of key intermediates of synthesis of modern medical preparations.