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Mol Biol Cell. 2014 Jun;25(11):1715-29. doi: 10.1091/mbc.E13-12-0730. Epub 2014 Apr 2.

Primary cilia in stem cells and neural progenitors are regulated by neutral sphingomyelinase 2 and ceramide.

Author information

1
Program in Developmental Neurobiology, Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912.
2
Division of Hematology/Oncology, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425 ebieberich@gru.edu spassisd@musc.edu.
3
Program in Developmental Neurobiology, Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912 ebieberich@gru.edu spassisd@musc.edu.

Abstract

We show here that human embryonic stem (ES) and induced pluripotent stem cell-derived neuroprogenitors (NPs) develop primary cilia. Ciliogenesis depends on the sphingolipid ceramide and its interaction with atypical PKC (aPKC), both of which distribute to the primary cilium and the apicolateral cell membrane in NP rosettes. Neural differentiation of human ES cells to NPs is concurrent with a threefold elevation of ceramide-in particular, saturated, long-chain C16:0 ceramide (N-palmitoyl sphingosine) and nonsaturated, very long chain C24:1 ceramide (N-nervonoyl sphingosine). Decreasing ceramide levels by inhibiting ceramide synthase or neutral sphingomyelinase 2 leads to translocation of membrane-bound aPKC to the cytosol, concurrent with its activation and the phosphorylation of its substrate Aurora kinase A (AurA). Inhibition of aPKC, AurA, or a downstream target of AurA, HDAC6, restores ciliogenesis in ceramide-depleted cells. Of importance, addition of exogenous C24:1 ceramide reestablishes membrane association of aPKC, restores primary cilia, and accelerates neural process formation. Taken together, these results suggest that ceramide prevents activation of HDAC6 by cytosolic aPKC and AurA, which promotes acetylation of tubulin in primary cilia and, potentially, neural processes. This is the first report on the critical role of ceramide generated by nSMase2 in stem cell ciliogenesis and differentiation.

PMID:
24694597
PMCID:
PMC4038499
DOI:
10.1091/mbc.E13-12-0730
[Indexed for MEDLINE]
Free PMC Article

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