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Suppressing phagocyte activation by overexpressing the phosphatidylserine lipase ABHD12 preserves sarmopathic nerves
Journal article   Peer reviewed

Suppressing phagocyte activation by overexpressing the phosphatidylserine lipase ABHD12 preserves sarmopathic nerves

Caitlin B. Dingwall, Yo Sasaki, Amy Strickland, Tong Wu, Daniel W. Summers, A. Joseph Bloom, Aaron DiAntonio and Jeffrey Milbrandt
iScience, Vol.28(6), 112626
06/20/2025
DOI: 10.1016/j.isci.2025.112626

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Abstract

Programmed axon degeneration (AxD) is a hallmark of many neurodegenerative diseases. In healthy axons, NMNAT2 inhibits SARM1, the key executioner of AxD, to keep it from depleting NAD+ and triggering axon destruction. AxD was assumed to be governed by axon-intrinsic mechanisms, independent of external factors. However, using a human disease model of neuropathy caused by hypomorphic NMNAT2 mutations resulting in chronic SARM1 activation, we demonstrated that neuronal SARM1 can initiate macrophage-mediated axon elimination long before stressed-but-viable axons would otherwise succumb to intrinsic metabolic failure. Chronic SARM1 activation causes axonal blebbing and disrupts phosphatidylserine (PS), a signaling molecule that promotes axon engulfment by macrophages. Neuronal expression of ABDH12, a PS lipase, reduces macrophage activation, preserves axons, and rescues motor function in this model, suggesting that PS dysregulation is an early SARM1-dependent axonal stress signal. Blocking macrophage-mediated axon elimination could be a promising therapeutic strategy for SARM1-dependent neurological diseases. [Display omitted] •NMNAT2 deletion is sufficient to evoke chronic SARM1 activity in uninjured neurons•Chronic SARM1 activation triggers axon blebbing and phosphatidylserine exposure•Axon blebbing occurs in a sarmopathy mouse model•Neuronal ABHD12 overexpression in sarmopathy mouse model rescues motor neuropathy
ABHD12 axons macrophages neuroinflammation Phosphatidylserine SARM1

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