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. Heatand 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.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - Jan 21 2020
Bibliographical noteFunding Information:
Competing interest statement: M.K.E. is named as an inventor on patents related to cloning and cultivation of the Norwalk virus genome and is a consultant to and received research funding from Takeda Vaccines, Inc. R.L.A. has received research funding from Takeda Vaccines, Inc.
ACKNOWLEDGMENTS. This research was supported by in part by NIH Grant P01 AI57788; the Texas Medical Center Digestive Diseases Center supported by PHS Grants P01AI 057788 (to M.K.E.) and P30 DK 56338 from the NIH; by Agriculture and Food Research Initiative Competitive Grant 2011-68003-30395 from the US Department of Agriculture, National Institute of Food and Agriculture (to M.K.E.); by Japan Agency for Medical Research and Development Grants JP18fk0108034 and JP19fk0108102 (to K.M.); Japan Society for the Promotion of Science KAKENHI Grant JP18K07153 (to K.M.); NIH grants R01AG034389 and R01NS095215 (to E.B.); National Science Foundation Grant 1615874 (to E.B.); Advanced Technology Core Laboratories (Baylor College of Medicine), specifically the Integrated Microscopy Core with funding from CPRIT (RP150578, RP170719); the Genomic and RNA Profiling Core with funding from NIH S10 Grant 1S10OD023469; and the Protein and Monoclonal Antibody Production Core, the Flow Cytometry Core at Baylor College of Medicine with funding from the NIH (CA125123, The Dan L Duncan Comprehensive Cancer Center, and Baylor College of Medicine Office of Research). We thank Xiaomin Yu and Yoko Yamaoka for technical assistance and Alan Hofmann for helpful discussions.
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- Acid sphingomyelinase
- Bile acid
ASJC Scopus subject areas