Androgen Modulation of Foxp1 and Foxp2 in the Developing Rat Brain: Impact on Sex Specific Vocalization

Abstract

Sex differences in vocal communication are prevalent in both the animals and humans. The mechanism(s) mediating gender differences in human language are unknown, although, sex hormones, principally androgens, play a central role in the development of vocalizations in a wide variety of animal species. The discovery of FOXP2 has added an additional avenue for exploring the origins of language and animal communication. The FOXP2 gene is a member of the forkhead box P (FOXP) family of transcription factors. Prior to the prenatal androgen surge in male fetuses, we observed no sex difference for Foxp2 protein levels in cultured cells. In contrast, 24 hours after the onset of the androgen surge, we found a sex difference for Foxp2 protein levels in cultured cortical cells with males having higher levels than females. Furthermore, we observed the potent nonaromatizable androgen dihydrotestosterone altered not only Foxp2 mRNA and protein levels but also Foxp1. Androgen effects on both Foxp2 and Foxp1 were found to occur in the striatum, cerebellar vermis, and cortex. Immunofluorescence microscopy and coimmunoprecipitation demonstrate Foxp2 and the androgen receptor protein interact. Databases for transcription factor binding sites predict a consensus binding motif for androgen receptor on the Foxp2 promoter regions. We also observed a sex difference in rat pup vocalization with males vocalizing more than females and treatment of females with dihydrotestosterone eliminated the sex difference. We propose that androgens might be an upstream regulator of both Foxp2 and Foxp1 expression and signaling. This has important implications for language and communication as well as neuropsychiatric developmental disorders involving impairments in communication.

FoxP2 Expression in a Highly Vocal Teleost Fish with Comparisons to Tetrapods

“…Comparison of the brain expression pattern of FoxP2 in midshipman with findings in other teleosts, as well as in mice and birds, suggests a pattern of evolutionarily conserved FoxP2-expressing brain regions. We also report extensive colocalization of FoxP2 with steroid-signaling pathways, consistent with a recent study of mice showing androgen-dependent changes in FoxP2 mRNA expression levels [Bowers et al, 2014]. …”

“…The report of Bowers et al [2014] that androgens influence FoxP2 mRNA and/or protein levels in the striatum, the cerebellar vermis, and the cortex of mice during embryonic and postnatal development led us to compare sites of FoxP2 expression in midshipman with steroidsignaling pathways (Table 1). Two thirds of the FoxP2-positive sites express androgen (AR) and/or estrogen (ERα, ERβ1, and ERβ2) receptors or the enzyme aromatase (estrogen synthase) that converts testosterone to estrogen [ Table 1; see Forlano and Bass, 2011, for review].…”

Prenatal exposure to sodium valproate alters androgen receptor expression in the developing cerebellum in a region and age specific manner in male and female rats

“…Forty micrometers sagittal sections were obtained from the mid-vermis and processed for immunohistochemistry as described elsewhere (Perez-Pouchoulen et al, 2016). Briefly, cerebellar sections were incubated with a polyclonal antibody against the AR (1:1500, rabbit anti-AR, Santa Cruz Biotechnology sc-816) in 0.4% PBS with Triton X-100 (PBS-T) for 48 h at 4 • C. This antibody has been validated to localize the AR in Purkinje neurons (Bowers et al, 2014;Perez-Pouchoulen et al, 2016;Qin et al, 2007), and in other neurons of the CNS (Wood and Keller-Wood, 2008). Subsequently, sections were incubated with biotinylated anti-rabbit secondary (1:500, Vector Laboratories) in 0.4% PBS-T for 90 min at room temperature with constant agitation.…”

“…Moreover, Purkinje neurons are known to express estrogen and progesterone receptors which both regulate neuroplasticity during cerebellar development (Haraguchi et al, 2012;Sakamoto et al, 2003Sakamoto et al, , 2001Sasahara et al, 2007;Tsutsui, 2008). Furthermore, the androgen receptor (AR) is also expressed by Purkinje neurons in the developing and adult cerebellum (Bowers et al, 2014;Perez-Pouchoulen et al, 2016;Qin et al, 2007), but its function in the neurobiology of the cerebellum remains unclear. In other brain regions, the AR regulates the expression of both cytoskeletal proteins such as tubulin (Jones and Oblinger, 1994;Matsumoto et al, 1994) and neurotrophic factors such as BDNF (brain-derived neurotrophic factor) (Yang et al, 2004) as it translocates to the cell nucleus functioning as a transcription factor (Chang et al, 1995;Lee and Chang, 2003).…”

Neural FoxP2 and FoxP1 expression in the budgerigar, an avian species with adult vocal learning

“…However, recent study in rodents showed that when exogenous androgen was administered, both mRNA and protein expression of FoxP2 and FoxP1 increased in the striatum, and vocalizations were also altered [43]. Interestingly, androgen receptor expression is high in Area X of zebra finches [44], but low in MMSt in budgerigars [45].…”