SARM1 Role in Injury Induced Activation and Recruitment of Macrophages
Board Location: #19
Discipline: Biological Sciences
Subcategory: Cell and Molecular Biology
Session: 1
Jaisha Shumpert - Ball State University
Co-Author(s): Julianna Bennett, Ball State University, Babatunde Oriyomi, Ball State University, Ashley Kalinski, Ball State University
Axon degeneration following traumatic injury is a self-destruction pathway driven by several proteins such as Sterile and Toll Interleukin-1 Receptor Motif containing (SARM1). Degeneration activates resident and circulating macrophages to help clean up debris at the injury site. Peripheral Nerve Injury (PNI); activates SARM1 to promote axon degeneration but the role of SARM1 in macrophages following PNI remains unclear. Macrophages are important to the repair process and are influenced by their microenvironment to be polarized into M1 (pro-inflammatory) or M2 (anti-inflammatory) states. We hypothesized Sarm1 -/- mice will have impaired macrophage function after PNI. To test this hypothesis, sciatic nerve macrophages were cultured from 3-day injured adult wildtype and Sarm1-/- mice. Macrophages were cultured in media containing m-CSF to promote survival. On day three, phagocytic activity was assessed by adding fluorescently labeled latex beads for two hours until cell death occurred. Macrophage cultures were fixed, and immunostaining was performed. Antibodies against CD68 were used to identify macrophages. A fluorescent microscope with a GFP and TRITC filter was used to identify latex beads and CD68 protein expression, respectively. Wildtype and Sarm1-/- macrophages showed successful uptake of the latex beads and were positively identified by CD68 expression. Quantification indicated Sarm1-/- macrophages showed less phagocytic activity compared to WT indicating reduced macrophage function. Our data suggests loss of Sarm1 leads to improper neuroinflammatory signaling which alters macrophage function. The role of SARM1 in this process was previously unknown. These, and future experiments, will further unlock our understanding of Sarm1’s role in injury signaling.
Funder Acknowledgement(s): Funded by the Louis Stokes Alliances for Minority Participation NSF INCLUDES (award number EES 2308500)
Faculty Advisor: Ashley Kalinski, acurren@bsu.edu
Role: I worked directly alongside my mentor Babatunde in understanding SARM1 role in macrophages following nerve injury. As a part of our research, I completed cell tissue cultures, phagocytosis assays and MAC immunostainings. I also contributed to aiding in prevalent results of understanding the role of CD68 expression in relation to neuroinflammatory signaling.