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

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

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetylation / drug effects
  • Animals
  • Aurora Kinase A / metabolism
  • Cell Differentiation / drug effects
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Ceramides / metabolism
  • Ceramides / pharmacology*
  • Cilia / drug effects
  • Cilia / metabolism*
  • Cytosol / drug effects
  • Cytosol / metabolism
  • Embryonic Stem Cells / cytology
  • Embryonic Stem Cells / drug effects
  • Embryonic Stem Cells / metabolism*
  • Enzyme Activation / drug effects
  • Histone Deacetylase 6
  • Histone Deacetylases / metabolism
  • Humans
  • Induced Pluripotent Stem Cells / cytology
  • Induced Pluripotent Stem Cells / drug effects
  • Induced Pluripotent Stem Cells / metabolism
  • Mice
  • Neural Stem Cells / cytology
  • Neural Stem Cells / enzymology
  • Neural Stem Cells / metabolism*
  • Organogenesis / drug effects
  • Protein Kinase C / metabolism
  • Protein Transport / drug effects
  • Proteolysis / drug effects
  • Sphingomyelin Phosphodiesterase / metabolism*
  • Spindle Apparatus / drug effects
  • Spindle Apparatus / metabolism
  • Tubulin / metabolism

Substances

  • Ceramides
  • Tubulin
  • AURKA protein, human
  • Aurora Kinase A
  • Protein Kinase C
  • SMPD3 protein, human
  • Sphingomyelin Phosphodiesterase
  • HDAC6 protein, human
  • Histone Deacetylase 6
  • Histone Deacetylases