Medial amygdala ERα expression influences monogamous behaviour of male prairie voles in the field

Formation of long-term pair-bonds is a complex process, involving multiple neural circuits and is context- and experience-dependent. While laboratory studies using prairie voles have identified the involvement of several neural mechanisms, efforts to translate these findings into predictable field outcomes have been inconsistent at best. Here we test the hypothesis that inhibition of oestrogen receptor alpha (ERα) in the medial amygdala of male prairie voles would significantly increase the expression of social monogamy in the field. Prairie vole populations of equal sex ratio were established in outdoor enclosures with males bred for high levels of ERα expression and low levels of prosocial behaviour associated with social monogamy. Medial amygdala ERα expression was knocked down in half the males per population. Knockdown males displayed a greater degree of social monogamy in five of the eight behavioural indices assessed. This study demonstrates the robust nature of ERα in playing a critical role in the expression of male social monogamy in a field setting.

Epigenetic Mechanisms in the Neurodevelopmental Theory of Depression

The genome (genes), epigenome, and environment work together from the earliest stages of human life to produce a phenotype of human health or disease. Epigenetic modifications, including among other things: DNA methylation, modifications of histones and chromatin structure, as well as functions of noncoding RNA, are coresponsible for specific patterns of gene expression. This refers also to mental disorders, including depressive disorders. Early childhood experiences accompanied by severe stressors (considered a risk factor for depression in adult life) are linked with changes in gene expression. They include genes involved in a response to stress (hypothalamic-pituitary-adrenal axis, HPA), associated with autonomic nervous system hyperactivity and with cortical, and subcortical processes of neuroplasticity and neurodegeneration. These are, among others: gene encoding glucocorticoid receptor, FK506 binding protein 5 gene (FKBP5), gene encoding arginine vasopressin and oestrogen receptor alpha, 5-hydroxy-tryptamine transporter gene (SLC6A4), and gene encoding brain-derived neurotrophic factor. How about personality? Can the experiences unique to every human being, the history of his or her development and gene-environment interactions, through epigenetic mechanisms, shape the features of our personality? Can we pass on these features to future generations? Hence, is the risk of depression inherent in our biological nature? Can we change our destiny?

FOXL2 antagonises the male developmental pathway in embryonic chicken gonads

FOXL2 is a conserved transcription factor with a central role in ovarian development and function. Studies in humans and mice indicate that the main role of FOXL2 is in the postnatal ovary, namely folliculogenesis. To shed light on the function and evolution of FOXL2 in the female gonad, we examined its role in embryonic avian gonads, using in ovo overexpression and knockdown. FOXL2 mRNA and protein are expressed female specifically in the embryonic chicken gonad, just prior to the onset of sexual differentiation. FOXL2 is expressed in the medullary cord cells, in the same cell type as aromatase (CYP19A1). In addition, later in development, expression also becomes localised in a subset of cortical cells, distinct from those expressing oestrogen receptor alpha. Misexpression of FOXL2 in the male chicken embryonic gonad suppresses the testis developmental pathway, abolishing local expression of the male pathway genes SOX9, DMRT1 and AMH and repressing Sertoli cell development. Conversely, knockdown of FOXL2 expression allows ectopic activation of SOX9 in female gonads. However, misexpression of FOXL2 alone was insufficient to activate aromatase expression in male gonads, while FOXL2 knockdown did not affect aromatase expression in females. These results indicate that FOXL2 plays an important role in embryonic differentiation of the avian ovary via antagonism of SOX9, but may be dispensable for aromatase activation at embryonic stages. The data suggest that FOXL2 has different roles in different species, more central for embryonic ovarian differentiation in egg-laying vertebrates.

Evaluating the oestrogenic activities of aqueous root extract of Asparagus africanus Lam in female Sprague-Dawley rats and its phytochemical screening using Gas Chromatography-Mass Spectrometry (GC/MS)

Asparagus africanus Lam. is a plant used traditionally for natal care. This study evaluates the oestrogenic activities of aqueous root extract and screens for possible bioactive phytochemicals. Oestrogenicity of A. africanus was evaluated in ovariectomised rats treated with 50, 200, and 800 mg/kgBW doses twice daily for three days. Ethinyl estradiol (EE)1 mg/kg was used as positive control, and hormonal analysis and gene expression were carried out. The findings demonstrated that the extract produced a dose-dependent increase in the oestrogen levels with a significant increase compared to untreated rats. Pre-treatment with oestrogen receptor antagonist (ORA) prior to A. africanus treatment reversed the trend. Gene expression analysis on rats treated with 200 mg/kgBW A. africanus showed significant (p < 0.005) upregulation of oestrogen receptor alpha (ERα), while pre-treating animals with (ORA) significantly (p < 0.005) increased the expression of calbindin 3 (Calb3) in the EE group as compared to the untreated rats. The GC/MS results showed the presence of steroidal saponins such as stigmasterol and sarsasapogenin. These might be the bioactive constituents that exhibited these activities. The oestrogenic properties of A. africanus revealed in this study could contribute to the antifertility properties of the plant. However, further pharmacological studies are required to confirm the antifertility effect.