Nascent HSPCs acquire definitive hematopoietic characteristics only when they develop into fetal HSPCs; however, the mechanisms underlying fetal HSPC development are poorly understood.
The research team led by Prof. LIU Feng at Institute of Zoology of Chinese Academy of Sciences and Prof. ZHANG Yong at Tongji University profiled the chromatin accessibility and transcriptional features of zebrafish nascent- and fetal HSPCs using ATAC-seq and RNA-seq and revealed dynamic changes during HSPC transition. Functional assays demonstrated that chromatin remodeler-mediated epigenetic programming facilitates fetal HSPC development in vertebrates. Systematical screening of chromatin remodeler-related genes identified that smarca5 is responsible for the maintenance of chromatin accessibility at promoters of hematopoiesis-related genes in fetal HSPCs. Mechanistically, Smarca5 interacts with Nucleolin to promote chromatin remodeling, thereby facilitating genomic binding of transcription factors to regulate expression of hematopoietic regulators such as bcl11ab. The results unravel a new role of epigenetic regulation and reveal that Smarca5-mediated epigenetic programming is responsible for fetal HSPC development, which will provide new insights into the generation of functional HSPCs both in vivo and in vitro. The study was published in BLOOD on August 5.
