Aleida Olivares

Luteinizing hormone (LH) is a gonadotropin found in both blood and pituitary tissue, and it plays a critical role in reproductive regulation in ruminants and other species. Distinct isoforms produced by post-translational modifications have been previously reported in the pituitary gland of ovariectomized cows and castrated bulls, treated with progesterone and estradiol, respectively. However, it remains unclear whether variations exist in the molecular forms of this hormone in intact prepubertal cattle. Anterior pituitary extracts of steers and heifers underwent chromatofocusing across a pH gradient (10–3.5), allowing classification of the eluted hormone forms into basic (pH ≥ 7.5), neutral (pH 7.4–6.5), and acidic fractions (pH ≤ 6.4) and on the basis of distinct isoforms (12 peaks of A–K). Radioimmunoassay was used to establish the immunological activity of LH isoforms. Overall, basic LH isoforms were present at higher concentrations than neutral or acidic forms in both steers and heifers. However, in steers the analysis by distinct isoforms of LH exhibited a slightly greater proportion of acidic isoforms J (pH 3.4–5.4) and neutral isoform G (pH 6–6.9) compared to heifers. In contrast, heifers showed slightly higher proportions of basic isoforms B (pH 9.2–9.9) and E (pH 7.8–8.7), neutral isoform F (pH 7.1–7.7), and acidic isoforms I (pH 5.7–6.4) and K (pH 3.3–4.9) than steers. Notably, the overall pituitary LH patterns observed in both groups were consistent with previously reported profiles, suggesting that these patterns are relatively stable despite physiological variation. Nevertheless, the subtle differences identified between sexes suggest that sex may influence the synthesis of LH isoforms at the pituitary level.

The CatSper channel localizes exclusively in the flagella of sperm cells. The Catsper1 protein, together with three pore units, is essential for the CatSper Channel formation, which produces flagellum hyperactivation and confers sperm fertility. Catsper1 expression is dependent on Sox transcription factors, which can recognize in vitro at least three Sox binding sites on the promoter. Sox transcription factors have calmodulin-binding domains for nuclear importation. Calmodulin (CaM) is affected by the specific inhibitor calmidazolium (CMZ), which prevents the nuclear transport of Sox factors. In this work, we assess the regulation of the Catsper1 promoter in vivo by Sox factors in the murine testis and evaluate the effects of the inhibitor calmidazolium on the expression of the Casper genes, and the motility and fertility of the sperm. Catsper1 promoter has significant transcriptional activity in vivo; on the contrary, three Sox site mutants in the Catsper1 promoter reduced transcriptional activity in the testis. CaM inhibition affects Sox factor nuclear transport and has notable implications in the expression and production of Catsper1, as well as in the motility and fertility capability of sperm. The molecular mechanism described here might conform to the basis of a male contraceptive strategy acting at the transcriptional level by affecting the production of the CatSper channel, a fundamental piece of male fertility.

CATSPER1 gene encodes a pore-forming and pH-sensing subunit of the CatSper Ca²⁺- permeable channel, a protein in the flagellum essential for sperm hyperactivation. Previous studies have shown that the murine Catsper1 gene promoter is regulated by different Sox proteins. Likewise, it is acknowledged that the human CATSPER1 gene promoter sequence is enriched in potential interaction sites for the sex-determining region Y gene (SRY), which suggest a novel regulatory transcriptional mechanism for CatSper1 channel expression. Therefore, in this work, we sought to determine whether the human CATSPER1 gene expression is regulated by the SRY transcription factor. To this end, a series of deletions and mutations were introduced in the wild- type CATSPER1 gene promoter to eliminate the SRY sites, and the different constructs were tested for their ability to activate transcription in human embryonic kidney and murine spermatogonial germ cell lines (HEK-293 and GC1-spg, respectively) using luciferase assays. In addition, by using a strategy that combines electrophoretic mobility shift assays (EMSA) and chromatin immunoprecipitation (ChIP) we investigated whether the CATSPER1 gene expression is regulated by the SRY transcription factor both in vitro and in vivo. Our results show that the transcriptional factor SRY specifically binds to different sites in the promoter sequence and has the ability to control CATSPER1 gene transcription.

Numerous clinical studies have reported the association between high circulating levels of lipocalin-2 (LCN2) and metabolic diseases. However, only few studies have addressed sexually dimorphic, either in its circulating concentration or in its expression in other organs. To the best of our knowledge, LCN2 and the 24p3 receptor (24p3R), have not been identified in gonads; therefore, the present study analyzed their mRNA expression profile and cellular localization in gonads collected from fetal rats at 21 days post coitum, as well as from neonatal rats at 0, 2, 4, 6, 12, 20 and 30 postnatal days. Semiquantitative polymerase chain reaction and immunohistochemical assays revealed that the LCN2 mRNA during perinatal and pre‑pubertal stages presented a sex‑specific expression pattern, being higher in ovaries than in testes collected at these stages. Furthermore, the mRNA levels of the long and short isoforms of the 24p3R (507 and 350 bp, respectively), were lower in female gonads from postnatal day 0 onwards in comparison with the levels observed in males, but before birth, the short isoform of the 24p3R was higher in ovaries than in testes. In addition, in females, the abundance of mRNA of this isoform was drastically diminished at 24 h after birth. Furthermore, this specific expression profile of LCN2 and 24p3R at perinatal and prepubertal stages coincides with events of cellular proliferation and apoptosis within both gonads. Immunohistochemical assays revealed that in ovaries, LCN2 and 24p3R are present in germinal and somatic cells of follicles, while in testes, this adipokine and its receptor are only located in germinal cells. These findings suggest that in murine gonads, LCN2/24p3R signaling may be involved either in cell proliferation or cell death driven by gonadotropin‑independent or ‑dependent mechanisms.

Through research carried out in the last 25 years about the breast cancer etiology, it has been possible to estimate that less than 10 % of patients who are diagnosed with the condition are carriers of some germline or somatic mutation. The clinical reports of breast cancer patients with healthy twins and the development of disease in women without high penetrance mutations detected, warn the participation more factors in the transformation process. The high incidence of mammary adenocarcinoma in the modern woman and the urgent need for new methods of prevention and early detection have demanded more information about the role that environment and lifestyle have on the transformation of mammary gland epithelial cells. Obesity, alcoholism and smoking are factors that have shown a close correlation with the risk of developing breast cancer. And although these conditions affect different cell regulation levels, the study of its effects in the mechanisms of transcriptional and epigenetic regulation is considered critical for a better understanding of the loss of identity of epithelial cells during carcinogenesis of this tissue. The main objective of this review was to establish the importance of changes occurring to transcriptional level in the mammary gland as a consequence of acute or chronic exposure to harmful products such as obesity-causing foods, ethanol and cigarette smoke components. At analyze the main studies related to topic, it has concluded that the understanding of effects caused by the lifestyle factors in performance of the transcriptional mechanisms that determine gene expression of the mammary gland epithelial cells, may help explain the development of this disease in women without genetic propensity and different phenotypic manifestations of this cancer type.

Survival rate in ovarian cancer depends on the stage of the disease. RSK4, which has been considered as a tumor suppressor factor, controls cells invasion due to its antiinvasive and antimetastatic properties. Modulation of RSK4 expression could be an important event to increase the survival rate in ovarian cancer patients. Thus, the goal of the present study was to establish the differences in RSK4 expression among normal, benign and malignant ovarian tissues and to determine whether antineoplastic drugs regulate its expression in SKOV3 and TOV-112D cells. RSK4 levels in 30 malignant ovarian tumors, 64 benign tumors and 36 normal ovary tissues were determined by reverse transcription polymerase chain reaction and Western blot. Modulation of RSK4 expression by two antineoplastic drugs (cisplatin and vorinostat) was also studied in the SKOV3 and TOV-112D ovarian cancer cell lines using the same techniques. RSK4 mRNA and protein levels were decreased in malignant ovarian tumors as compared to benign tumors and normal tissue. These low-RSK4 levels were significantly associated with advanced stages of ovarian cancer. RSK4 expression was increased after incubation of SKOV3 and TOV-112D cell lines with cisplatin and vorinostat for 24 h. The combination of these antineoplastic drugs did not produce a synergistic or additive effect. These results suggest that RSK4 is expressed at low levels in malignant ovarian tumors, which correlates with advanced stages of the disease. Additionally, RSK4 expression is regulated by cisplatin and vorinostat in two ovarian cancer cell lines.

The purpose of this study was to investigate the effect of 1,1,1‐trichloro‐2,2‐bis‐(chlorophenyl)ethane (DDT), 1,1‐bis‐(chlorophenyl)‐2,2‐dichloroethene (DDE), and 1,1‐dichloro‐2,2‐bis(chlorophenyl)ethane (DDD) isomers on COX‐2 expression in a human trophoblast‐derived cell line. Cultured HTR‐8/SVneo trophoblast cells were exposed to DDT isomers and its metabolites for 24 h, and COX‐2 mRNA and protein expression were assessed by RT‐PCR, Western blotting, and ELISA. Prostaglandin E₂ production was also measured by ELISA. Both COX‐2 mRNA and protein were detected under control (unexposed) conditions in the HTR‐8/SVneo cell line. COX‐2 protein expression and prostaglandin E₂ production but not COX‐2 mRNA levels increased only after DDE and DDD isomers exposure. It is concluded that DDE and DDD exposure induce the expression of COX‐2 protein, leading to increased prostaglandin E2 production. Interestingly, the regulation of COX‐2 by these organochlorines pesticides appears to be at the translational level. © 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:454‐460, 2012; View this article online at wileyonlinelibrary.com. DOI 10:1002/jbt.21444