A Critical Analysis of the Role of SNARE Protein SEC22B in Antigen Cross-Presentation

S. Julia Wu, Yashar S. Niknafs, Stephanie H. Kim, Katherine Oravecz-Wilson, Cynthia Zajac, Tomomi Toubai, Yaping Sun, Jayendra Prasad, Daniel Peltier, Hideaki Fujiwara, Israel Hedig, Nathan D. Mathewson, Rami Khoriaty, David Ginsburg, Pavan Reddy

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Cross-presentation initiates immune responses against tumors and viral infections by presenting extracellular antigen on MHC I to activate CD8+ T cell-mediated cytotoxicity. In vitro studies in dendritic cells (DCs) established SNARE protein SEC22B as a specific regulator of cross-presentation. However, the in vivo contribution of SEC22B to cross-presentation has not been tested. To address this, we generated DC-specific Sec22b knockout (CD11c-Cre Sec22bfl/fl) mice. Contrary to the paradigm, SEC22B-deficient DCs efficiently cross-present both in vivo and in vitro. Although in vitro small hairpin RNA (shRNA)-mediated Sec22b silencing in bone-marrow-derived dendritic cells (BMDCs) reduced cross-presentation, treatment of SEC22B-deficient BMDCs with the same shRNA produced a similar defect, suggesting the Sec22b shRNA modulates cross-presentation through off-target effects. RNA sequencing of Sec22b shRNA-treated SEC22B-deficient BMDCs demonstrated several changes in the transcriptome. Our data demonstrate that contrary to the accepted model, SEC22B is not necessary for cross-presentation, cautioning against extrapolating phenotypes from knockdown studies alone.

Original languageEnglish
Pages (from-to)2645-2656
Number of pages12
JournalCell Reports
Volume19
Issue number13
DOIs
Publication statusPublished - Jun 27 2017
Externally publishedYes

Keywords

  • RNA-seq
  • SEC22B
  • SNARE protein
  • cross-presentation
  • dendritic cell
  • off-target effect

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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