Molecular priming of reverse migration in neutrophil subpopulations

Chronic inflammation is a detrimental status, preventing efficient wound healing. In chronic inflammation, neutrophils remain active at the wound site after the acute inflammation period, continuing to recruit other immune cells and potentially exacerbating the wound condition. One approach for inflammation resolution is to promote neutrophil reverse migration, a path that some neutrophils take in regular wound healing processes. While signals and triggers have been identified for reverse migration, the underlying molecular regulation remains elusive. This study aims to decipher the molecular status of neutrophils during wound healing, with a long-term goal to identify determinants that promote neutrophil reverse migration. Our recent work has shown that there are four neutrophil subpopulations in zebrafish either in normal development or in burn wound healing conditions. The K99 Phase of this study will focus on identifying key subpopulations among them that are involved in reverse migration, tracking the dynamics of their molecular profiles, and examining the necessity and sufficiency of candidate subpopulations or factors in the process. By connecting molecular scale changes to the migration behavior, this part of the study will provide insight into developing novel strategies to achieve controlled neutrophil clearance for inflammation resolution. In this phase, I will receive training and develop skills in applying quantitative imaging on zebrafish models to visualize cellular behaviors. This training will prepare me to become an independent investigator who develops strategies to promote wound healing by integrating genetic and genomic approaches to study the role of innate immune cells in wound healing and regeneration. The R00 Phase of this study focuses on the role of opsin and phototransduction pathway in regulating neutrophil behavior, which is a wound-healing related molecular signature identified from my current work. By applying quantitative imaging skills on genetic models, I will assess the impact of light on neutrophil function, exploring the connection from physical interactions to molecular regulation in the control of neutrophil behaviors. In addition to scientific progression, this proposal also provides a detailed plan to facilitate my transition to independency. Aside from receiving training for imaging-related research skills, I will improve my communication, teaching and mentoring, and leadership skills through formal and informal interaction with my advisory committee, attending and presenting at conferences, mentoring students, and participating in leadership skill workshops. The proposed study will be conducted under the mentorship of Dr. Anna Huttenlocher and the support of my advisory committee. The Huttenlocher lab in the Department of Medical Microbiology and Immunology at University of Wisconsin-Madison provides an ideal environment for me to develop both research and non-research-related skills, supporting me in achieving research independency. Project Number: 1K99GM160698-01A1 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of General Medical Sciences (NIGMS) | Principal Investigator: Yiran Hou | Institution: UNIVERSITY OF WISCONSIN-MADISON, MADISON, WI | Award Amount: $116,005 | Activity Code: K99 | Study Section: Special Emphasis Panel[ZRG1 IIDA-T (80)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11352238