부산대학교 도서관

Neutrophils are important effector cells in innate immunity, possessing a wide range of effector functions, including reactive oxygen species (ROS) production, phagocytosis and chemotaxis. These properties enable neutrophils to rapidly respond to stimulation and orchestrate protective immunity. Currently, the transcriptional regulatory networks underlying neutrophil activation and function remain largely unexplored. Of note, there is partial understanding of transcription factors (TFs) that act as key regulators to control neutrophil development and inflammatory responses. Neutrophils undergo tightly controlled genomic and transcriptional changes while transitioning between bone marrow, blood, and tissue sites. However, the molecular mechanisms underlining neutrophil function during inflammation have yet to be fully elucidated. To determine the transcription factor networks that shape these responses, we have undertaken integrated transcriptional and chromatin analyses of neutrophils during acute inflammation and revealed distinct sets of putative transcription factors (TFs) associated with control of neutrophil differentiation and inflammatory responses. To investigate the regulatory role of the selected TFs in neutrophils, I utilised HoxB8 myeloid progenitors as a model system for in vitro production of neutrophils and generated stable knockout lines for JUNB, RELB, IRF5, RFX2, KLF6, and RUNX1 in Hoxb8 myeloid progenitors, using the CRISPR/Cas9 mediated system. Additionally, I have demonstrated the importance of RUNX1, KLF6 in neutrophil differentiation. RUNX1, KLF6 deletion in HoxB8 progenitors caused a block in neutrophil differentiation and produced lower levels of mature neutrophils. KLF6 and RUNX1 deficient neutrophils also displayed impaired transmigration properties. Consistent with findings in the Hoxb8 in vitro model, conditional deletion of RUNX1 in myeloid populations produced lower mature neutrophils in the bone marrow. To validate the functional role of the selected TFs in neutrophil activation, I examined the consequence of CEBPβ, RELB, IRF5, JUNB knockouts on neutrophil effector functions, such as phagocytosis, cytokine production, generation of ROS, formation of NETs and bacterial killing. I found that RELB, IRF5, JUNB knockout significantly affect the ability of neutrophils to produce inflammatory mediators. JUNB and RELB also contribute to neutrophil phagocytosis, ROS generation and NETosis.