Yuan Lab discovers the role of RIPK1 in mediating axonal degeneration in amyotrophic lateral sclerosis (ALS)

Graphic of Microglia and Oligodendrocyte

Axonal degeneration is frequently observed before the death of neuronal cell bodies in patients with neurodegenerative disorders including ALS and contributes significantly to neurological disability. While blocking axonal degeneration may represent an important therapeutic goal, the mechanism of axonal degeneration is unclear. In a recent paper published in Science by Yuan lab, Ito et al. investigated the role of RIPK1 in Optn-/- mice. Loss-of-function mutations in the Optineurin (Optn)gene have been implicated in both familial and sporadic cases of ALS. The authors demonstrated that optineurin actively suppressed RIPK1-dependent signaling by regulating its turnover. Loss-of-Optn led to progressive dysmyelination and axonal degeneration through engagement of necroptotic machinery, including RIPK1, RIPK3 and MLKL, in the CNS. Furthermore, RIPK1/RIPK3-mediated axonal pathology was commonly observed in SOD1G93A transgenic mice and pathological samples from human ALS. Thus, RIPK1/RIPK3 plays a critical role in mediating progressive axonal degeneration and inhibiting RIPK1 kinase may provide an axonal protective strategy for the treatment of ALS and other human degenerative diseases characterized by axonal degeneration.