Inhibition of glucosylceramide synthase stimulates autophagy flux in neurons.
Aggregate-prone mutant proteins, such as α-synuclein and huntingtin, play a prominent role in the pathogenesis of various neurodegenerative disorders; thus, it has been hypothesized that reducing the aggregate-prone proteins may be a beneficial therapeutic strategy for these neurodegenerative disorders. Here, we identified two previously described glucosylceramide (GlcCer) synthase inhibitors, DL-threo-1-Phenyl-2-palmitoylamino-3-morpholino-1-propanol and Genz-123346(Genz), as enhancers of autophagy flux. We also demonstrate that GlcCer synthase inhibitors exert their effects on autophagy by inhibiting AKT-mammalian target of rapamycin (mTOR) signaling. More importantly, siRNA knock down of GlcCer synthase had the similar effect as pharmacological inhibition, confirming the on-target effect. In addition, we discovered that inhibition of GlcCer synthase increased the number and size of lysosomal/late endosomal structures. Although inhibition of GlcCer synthase decreases levels of mutant α-synuclein in neurons, it does so, according to our data, through autophagy-independent mechanisms. Our findings demonstrate a direct link between glycosphingolipid biosynthesis and autophagy in primary neurons, which may represent a novel pathway with potential therapeutic value for the treatment of Parkinson's disease. Inhibition of GlcCer synthase enhances autophagy by inhibiting AKT-mTOR signaling, and increases the number and size of lysosomal/late endosomal structures. Furthermore, inhibition of GlcCer synthase decreased levels of mutant α-synuclein in neurons, which may represent a potential therapeutic target for Parkinson's disease.
Pfizer Neuroscience Research Unit, Cambridge, Massachusetts, USA.
Wei
W
Shen
Anastasia G
AG
Henry
Katrina L
KL
Paumier
Li
L
Li
Kewa
K
Mou
John
J
Dunlop
Zdenek
Z
Berger
Warren D
WD
Hirst
D000818:Animals; D001343:Autophagy / Q000502:physiology*; D015153:Blotting, Western; D002478:Cells, Cultured; D004146:Dioxanes / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors*; D006028:Glycosphingolipids / Q000096:biosynthesis; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008614:Meperidine / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009474:Neurons / Q000502:physiology*; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010300:Parkinson Disease / Q000235:genetics; D010766:Phosphorylation; D061251:Primary Cell Culture; D011759:Pyrrolidines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
C520404:(2-(2',3'-dihydrobenzo(1,4)dioxin-6'-yl)-2-hydroxy-1-pyrrolidin-1-ylmethylethyl)nonanoic acid amide; D004146:Dioxanes; D004791:Enzyme Inhibitors; D006028:Glycosphingolipids; D011759:Pyrrolidines; D034741:RNA, Small Interfering; C026733:4-propionyloxy-4-phenyl-N-methylpiperidine; D008614:Meperidine; D005964:Glucosyltransferases; C023246:ceramide glucosyltransferase; D051058:Oncogene Protein v-akt
Parkinson's disease; glucosylceramide; lysosome