Prenatal testosterone triggers long-term behavioral changes in male zebra finches: unravelling the neurogenomic mechanisms

Abstract

Background Maternal hormones, like testosterone, can strongly influence developing offspring, even generating long-term organizational effects on adult behavior; yet, the mechanisms facilitating these effects are still unclear. Here, we experimentally elevated prenatal testosterone in the eggs of zebra finches (Taeniopygia guttata) and measured male aggression in adulthood along with patterns of neural gene expression (RNA-seq) and DNA methylation (MethylC-Seq) in two socially relevant brain regions (hypothalamus and nucleus taenia of the amygdala). We used enrichment analyses and protein-protein interaction networks to find candidate processes and hub genes potentially affected by the treatment. We additionally identified differentially expressed genes that contained differentially methylated regions. Results We found that males from testosterone-injected eggs displayed more aggressive behaviors compared to males from control eggs. Hundreds of genes were differentially expressed, particularly in the hypothalamus, including potential aggression-related hub genes (e.g., brain derived neurotrophic factor). There were also enriched processes with well-established links to aggressive phenotypes (e.g., somatostatin and glutamate signaling). Furthermore, several highly connected genes identified in protein-protein interaction networks also showed differential methylation, including adenylate cyclase 2 and proprotein convertase 2. Conclusions These results highlight genes and processes that may play an important role in mediating the effects of prenatal testosterone on long-term phenotypic outcomes, thereby providing insights into the molecular mechanisms that facilitate hormone-mediated maternal effects.

Neurogenomic landscape associated with status-dependent cooperative behavior

“…Using previously developed microdissection protocols (Horton et al . 2020), we conducted transcriptome-level sampling of the pituitary, testes, and 10 brain nuclei comprising the entire SBN and a portion of the mesolimbic reward system (MRS) (Lopes and König 2020; Bentz et al . 2021b; Kabelik et al .…”

“…Using the most comprehensive transcriptome-level sampling of the SBN to-date (Lopes and König 2020; Bentz et al . 2021b; Kabelik et al .…”

“…Using previously developed microdissection protocols (Horton et al 2020), we conducted transcriptome-level sampling of the pituitary, testes, and 10 brain nuclei comprising the entire SBN and a portion of the mesolimbic reward system (MRS) (Lopes and König 2020;Bentz et al 2021b;Kabelik et al 2021;Bentz et al 2021a;Antunes et al 2021) (Figure 1F, Table S1.2) from nine territorial and seven floater males. A subset of these individuals were characterized for testosterone and cooperative phenotypes (Figure 1DE).…”

Prenatal maternal stress is associated with behavioural and epigenetic changes in Japanese quail

“…For example, J o u r n a l P r e -p r o o f Bentz et al showed that zebra finches from testosterone-injected eggs presented more aggressive behaviours than control males, and had several differentially expressed genes that were also differentially methylated. Their findings suggest that in ovo testosterone may induce epigenetic modifications that could influence aggression behaviour (Bentz et al, 2021).…”

“…To mimic the effects of PMS, eggs of zebra finches were previously injected with testosterone which lead to different expression of hundreds of genes particularly in the hypothalamus (Bentz et al, 2021). Some authors suggested that influences of PMS on epigenetic marks could be implicated in offspring behavioural changes J o u r n a l P r e -p r o o f including more hypotonia and lethargy (human: Conradt et al, 2013), modulations of locomotor activity (rat: Mychasiuk et al, 2011), greater fearfulness (human: Ostlund et al, 2016), poorer spatial learning abilities (mice: Benoit et al, 2015), more aggressive behaviour (zebra finches: Bentz et al, 2021) or different foraging strategies (chicken: Nätt et al, 2009). Birds, especially precocial, are ideal animal models to study and understand these phenomena.…”