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

Summary: 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...

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Main Authors: Caitlin B. Dingwall, Yo Sasaki, Amy Strickland, Tong Wu, Daniel W. Summers, A. Joseph Bloom, Aaron DiAntonio, Jeffrey Milbrandt
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:iScience
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Online Access:http://www.sciencedirect.com/science/article/pii/S2589004225008879
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Summary:Summary: 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.
ISSN:2589-0042