Stimulus-Dependent Expression of<i>Bdnf</i>Is Mediated by ATF2, MYT1L, and EGR1 Transcription Factors

Neurotrophins like BDNF have a key role in the proper functioning of the central nervous system, influencing numerous processes like memory formation and behavior. An imbalance in BDNF levels can lead to a wide range of diseases, including depression and neurodevelopmental disorders. While the potential therapeutic effects of BDNF are well-recognized, there is a knowledge gap in understanding the mechanisms governing BDNF expression levels. Here, we focused on the regulation of <i>Bdnf</i> gene expression in response to different stimuli, specifically studying the effects of neuronal activity and BDNF-TrkB signaling on <i>Bdnf</i> transcription in cultured neurons from rats of either sex. We used in vitro DNA pulldown combined with mass spectrometry to determine transcription factors that interact with the <i>Bdnf</i> promoters upon different stimuli and validated numerous known regulators, such as USF and AP1 family, and novel candidate regulators using reporter assays. We show that the USF family of transcription factors is specifically recruited after membrane depolarization, whereas the AP1 family participates in <i>Bdnf</i> regulation only after BDNF-TrkB signaling. We further describe ATF2, MYT1L, and EGR family as novel regulators of <i>Bdnf</i> expression by demonstrating their direct binding to <i>Bdnf</i> promoters using chromatin immunoprecipitation assays both in vitro and in vivo, showing their functional role in <i>Bdnf</i> gene expression and ultimately identifying their regulatory <i>cis</i>-elements in <i>Bdnf</i> promoters. Furthermore, our results show competition between ATF2, CREB, and AP1 family in regulating <i>Bdnf</i> levels. Collectively, our results provide insight into the regulation of <i>Bdnf</i> expression upon different stimuli.