Bile acids and ceramide overcome the entry restriction for GII.3 human norovirus replication in human intestinal enteroids

Proc Natl Acad Sci U S A. 2020 Jan 21;117(3):1700-1710. doi: 10.1073/pnas.1910138117. Epub 2020 Jan 2.

Abstract

Human noroviruses (HuNoVs) cause sporadic and epidemic outbreaks of gastroenteritis in all age groups worldwide. We previously reported that stem cell-derived human intestinal enteroid (HIE) cultures support replication of multiple HuNoV strains and that some strains (e.g., GII.3) replicate only in the presence of bile. Heat- and trypsin-treatment of bile did not reduce GII.3 replication, indicating a nonproteinaceous component in bile functions as an active factor. Here we show that bile acids (BAs) are critical for GII.3 replication and replication correlates with BA hydrophobicity. Using the highly effective BA, glycochenodeoxycholic acid (GCDCA), we show BAs act during the early stage of infection, BA-dependent replication in HIEs is not mediated by detergent effects or classic farnesoid X receptor or Takeda G protein-coupled receptor 5 signaling but involves another G protein-coupled receptor, sphingosine-1-phosphate receptor 2, and BA treatment of HIEs increases particle uptake. We also demonstrate that GCDCA induces multiple cellular responses that promote GII.3 replication in HIEs, including enhancement of 1) endosomal uptake, 2) endosomal acidification and subsequent activity of endosomal/lysosomal enzyme acid sphingomyelinase (ASM), and 3) ceramide levels on the apical membrane. Inhibitors of endosomal acidification or ASM reduce GII.3 infection and exogenous addition of ceramide alone permits infection. Furthermore, inhibition of lysosomal exocytosis of ASM, which is required for ceramide production at the apical surface, decreases GII.3 infection. Together, our results support a model where GII.3 exploits rapid BA-mediated cellular endolysosomal dynamic changes and cellular ceramide to enter and replicate in jejunal HIEs.

Keywords: acid sphingomyelinase; bile acid; ceramide; enteroid/organoid; norovirus.

Publication types

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

MeSH terms

  • Bile Acids and Salts / metabolism*
  • Bile Acids and Salts / pharmacology
  • Ceramides / metabolism*
  • Ceramides / pharmacology
  • Glycochenodeoxycholic Acid
  • Humans
  • Intestines / virology*
  • Norovirus / drug effects*
  • Receptors, G-Protein-Coupled
  • Sphingomyelin Phosphodiesterase / metabolism
  • Sphingosine-1-Phosphate Receptors
  • Virus Internalization / drug effects*
  • Virus Replication / drug effects*

Substances

  • Bile Acids and Salts
  • Ceramides
  • GPBAR1 protein, human
  • Receptors, G-Protein-Coupled
  • S1PR2 protein, human
  • Sphingosine-1-Phosphate Receptors
  • Glycochenodeoxycholic Acid
  • Sphingomyelin Phosphodiesterase