Abundance of estrogen receptors involved in non-canonical signaling in the dog testis

Estrogen receptors alpha and beta expression in different canine cancer types with an emphasis on hematopoietic malignancies

Estrogen receptors (ERs) are located in both healthy and neoplastic tissues. The type of estrogen receptor expressed varies depending on its location, tumor type, and species. Estrogen action is mediated by binding to ER and activating the transcriptional and signaling processes that result in the control of gene expression. There are two main types of estrogen receptors: ER alpha (ERα) and ER beta (ERβ). Both receptors are functionally different, they may act antagonistically and are distributed in different tissues but their structure is similar - as they are composed of 5 different domains: A/B, C, D, E, and F. The signaling pathway and hence regulation of the gene expression by ERs is a complex and multifactorial process that involves both genomic and nongenomic actions. In the human reproductive tract, both ERα and β are present, with predominant expression of ERβ, while there are no satisfactory data distinguishing the type of ERs expressed in the canine reproductive tract. In mammary gland neoplasia, a decreased or lacking ERα expression in humans is associated with a poorer prognosis. This is similar to dogs, where higher ERα expression intensity was noted in benign tumors than in carcinomas. In human hematopoietic malignancies, ERβ is a predominant receptor. Selective and non-selective ERβ agonists have an antiproliferative and pro-apoptotic effect on human lymphoma cell lines and may be effective in the therapy of ERβ positive lymphomas and leukemias. In canine lymphoma tissues, none or only marginal expression of ERs was detected over the decades. Considering available data, we conducted preliminary studies proving that, in contrast to humans, the dominant ER expressed in canine hematopoietic tumors is ERα.

G Protein-Coupled Estrogen Receptor (GPER) and ERs Are Modulated in the Testis-Epididymal Complex in the Normal and Cryptorchid Dog

There is growing evidence by the literature that the unbalance between androgens and estrogens is a relevant condition associated with a common canine reproductive disorder known as cryptorchidism. The role of estrogens in regulating testicular cell function and reproductive events is supposedly due to the wide expression of two nuclear estrogen receptors (ERs), ER-alpha and ER-beta and a trans-membrane G protein-coupled estrogen receptor (GPER) in the testis. In this study, immunohistochemistry, Western blotting and qRT-PCR were used to assess the distribution and expression of GPER in the testis-epididymal complex in the normal and cryptorchid dog. ER-alpha and ER-beta were also evaluated to better characterize the relative abundances of all three receptors. In addition, in these tissues, the expression level of two proteins as SOD1 and Nrf2 normally associated with oxidative stress was investigated to evaluate a possible relationship with ERs. Our data revealed changes in the distribution and expression of the GPER between the normal and cryptorchid dog. In particular, dogs affected by cryptorchidism showed an upregulation of GPER at level of the examined reproductive tract. Also considering the obtained result of a modulation of SOD1 and Nrf2 expression, we could hypothesize the involvement of GPER in the cryptorchid condition. Further studies are, however, necessary to characterize the role of GPER and its specific signaling mechanisms.

The uterusmasculinus of the Eurasian beaver (Castor fever L.) - The appraisal of fast hormone regulation by membrane androgen and estrogen receptors involvement

The phenomenon of remaining paramesonephric ducts (uterus masculinus) in males of some animal species concerning its role is still an unresolved issue. Now it is well-recognized that sex hormonal regulation of reproductive physiology involves also fast nongenomic control of cellular processes through noncanonical signaling. Herein, in the uterus masculinus of Eurasian beaver membrane androgen receptor (metal ion transporter Zrt- and Irt-like protein 9; ZIP9) and membrane estrogen receptor (G protein-coupled estrogen receptor; GPER) were studied. Scanning electron microscopy together with anatomical analysis revealed that Eurasian male beavers possess one double uterus (uterus duplex). Two odd parts open into the vagina but do not form a common lumen. The length of the horns is the most differential feature of this organ in studied animals. Uterus masculinus is not a tightly closed tubular structure. Histological analysis showed an analogy to the female uterus structure however no glands but gland-like structures were observed. The presence and abundant localization of ZIP9 and GPER proteins in cells of uterus masculinus was confirmed by immunohistochemistry while their expression was measured by western blotting. GPER expression in remnants was lower (P < 0.001) than those in the female uterus. Parallelly, the concentration of progesterone and estradiol but not testosterone was lower (P < 0.05 and P < 0.01, respectively) in comparison to the female uterus. Our study, for the first time, reports the involvement of fast hormonal regulation in the uterus masculinus of Eurasian beavers reflecting the participation of this organ in the creation local hormonal environment. Moreover, the uterus masculinus seems to be a useful research model for understanding and resolving urgent biological problems such as gender identities and having children by women with a lack of uterus or anatomical barriers on this level.

Influence of deoxynivalenol and zearalenone on the immunohistochemical expression of oestrogen receptors and liver enzyme genes in vivo in prepubertal gilts

Deoxynivalenol (DON) and zearalenone (ZEN) are often detected in plant materials used to produce feed for pre-pubertal gilts. Daily exposure to small amounts of these mycotoxins causes subclinical conditions in pigs and affects various biological processes (e.g. mycotoxin biotransformation). The aim of this preclinical study was to evaluate the effect of low monotonic doses of DON and ZEN (12 µg/kg body weight-BW-and 40 µg/kg BW, respectively), administered alone or in combination to 36 prepubertal gilts for 42 days, on the degree of immunohistochemical expression of oestrogen receptors (ERs) in the liver and the mRNA expression of genes encoding selected liver enzymes during biotransformation processes. The level of expression of the analysed genes proves that the tested mycotoxins exhibit variable biological activity at different stages of biotransformation. The biological activity of low doses of mycotoxins determines their metabolic activity. Therefore, taking into account the impact of low doses of mycotoxins on energy-intensive processes and their endogenous metabolism, it seems that the observed situation may lead to the activation of adaptation mechanisms.

Senescence and autophagy relation with the expressional status of non-canonical estrogen receptors in testes and adrenals of roe deer (Capreolus capreolus) during the pre-rut period

The roe deer bucks represent a spontaneous model to study the synchronized testicular involution and recrudescence cycles. However, cellular processes and hormonal control of steroidogenic glands are scarcely known. For the present study testes and adrenal glands obtained from roe deer during the pre-rut season were used. We aimed to determine (i) senescence and autophagy involvement in testis atrophy (immunohistochemical analysis for tumor suppressor protein encoded by the cyclin-dependent kinase inhibitor 2A; p16 and microtubule-associated protein 1A/1B-light chain 3; LC3, respectively), (ii) the size of the adrenal cortex and medulla (morphometric analysis), (iii) G-protein coupled estrogen receptor (GPER) and estrogen-related receptors (ERRs; type α, β, and Y) distribution and expression (qRT-PCR and immunohistochemical analyses) and (iv) serum testosterone and estradiol levels (immunoassay ELISA). This study revealed pre-rut characteristics of testis structure with the presence of both senescence and autophagy-positive cells and higher involvement of senescence, especially in spermatogenic cells (P < 0.05). In the adrenal cortex, groups of cells exhibiting shrinkage were observed. The presence of ERRs in cells of the seminiferous epithelium and interstitial Leydig cells and GPER presence distinctly in Leydig cells was revealed. In adrenals, these receptors were localized in groups of normal-looking cells and those with shrinkage. Morphometric analysis showed differences in cortex width which was smaller (P < 0.05) than that of the medulla. A weak immunohistochemical signal was observed for ERRβ when compared to ERRα and ERRγ. The mRNA expression level of ERRα and ERRγ was lower (P < 0.001 and P < 0.05, respectively) while ERRβ was higher (P < 0.001) in adrenals when compared to testes. mRNA GPER expression was similar in both glands. In the pre-rut season, the testosterone level was 4.89 ng/ml while the estradiol level was 0.234 ng/ml. We postulate that: (i) senescence and autophagy may be involved in both reinitiation of testis function and/or induction of abnormal processes, (ii) hormonal modulation of testis inactivity may affect adrenal cortex causing cell shrinkage, (iii) ERRs and GPER localization in spermatogenic cells and interstitial cells, as well as cortex cells, may maintain and control the morpho-functional status of both glands, and (iv) androgens and estrogens (via ERRs and GPER) drive cellular processes in the testis and adrenal pre-rut physiology.