Denton, Travis T.

Autophagy is a cellular digestion process that contributes to cellular homeostasis by the elimination of proteins and damaged organelles. Impaired autophagy has been implicated in aging‐related disorders and in neurodegenerative diseases, including motor neuron disorders. Therefore, upregulation of autophagy may serve as a promising therapeutic approach. Lanthionine ketenamine (LK), an amino acid metabolite found in mammalian brain tissue at low concentrations, activates autophagy in rat glioma and human neuroblastoma cells in vitro, as well as in hippocampus and cortex after in vivo administration. With the overall goal of using LK to induce autophagy flux to prevent age‐related motor neuron dysfunction, we recently tested the effects of two lanthionine ketenamine phosphonates (LK‐Ps) and one lanthionine ketenamine ethyl (ester) phosphonate (LKE‐P) on autophagy modulation in a mouse motor neuron‐like hybrid cell line (NSC‐34). For fluorescence visualization of autophagy flux, NSC‐34 cells were transfected with mCherry‐GFP‐LC3 plasmid. Motor neurons treated with LK analogs displayed increased autophagy flux measured by the ratio of mCherry area (lysosomes) over GFP area (autophagosomes that have not fused with lysosomes) compared to control cells. There results were corroborated by increased LC3‐II/LC3‐I ratio as measured by protein expression using Western blot; and presence of autophagic vacuoles identified using transmission electron microscopy. In conclusion, LK analogs constitute a promising tool to induce autophagy flux in motor neurons, which may serve to prevent age‐related motor axon withdrawal and muscle denervation.