The faah gene is the first direct target of estrogen in the testis: Role of histone demethylase LSD1

Estrogen (E₂) regulates spermatogenesis, yet its direct target genes have not been identified in the testis. Here, we cloned the proximal 50 flanking region of the mouse fatty acid amide hydrolase (faah) gene upstream of the luciferase reporter gene, and demonstrated its promoter activity and E ₂ inducibility in primary mouse Sertoli cells. Specific mutations in the E₂ response elements (ERE) of the faah gene showed that two proximal ERE sequences (ERE₂/3) are essential for E ₂-induced transcription, and chromatin immunoprecipitation experiments showed that E₂ induced estrogen receptor β binding at ERE₂/3 sites in the faah promoter in vivo. Moreover, the histone demethylase LSD1 was found to be associated with ERE₂/3 sites and to play a role in mediating E₂ induction of FAAH expression. E ₂ induced epigenetic modifications at the faah proximal promoter compatible with transcriptional activation by remarkably decreasing methylation of both DNA at CpG site and histone H3 at lysine 9. Finally, FAAH silencing abolished E₂ protection against apoptosis induced by the FAAH substrate anandamide. Taken together, our results identify FAAH as the first direct target of E₂.