PDPN and Anxiety: Further experiments using alternative Pdpn-down-regulation approaches like CRISPR-Cas9-based (Cong et al., 2013; Horvath et al., 2017; Ma et al., 2017) targeted Pdpn gene deletion could additionally contribute to the verification of the here proposed in vivo role of Pdpn in neurogenesis, NGF-mediated neuroprotection and anxiety-related behaviors.