Phospholipid Scramblase 1 regulates Toll-like receptor 9-mediated type I interferon production in plasmacytoid dendritic cells |
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Authors: | Amjad H Talukder Musheng Bao Tae Whan Kim Valeria Facchinetti Shino Hanabuchi Laura Bover Tomasz Zal Yong-Jun Liu |
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Affiliation: | 1.Department of Immunology, Center for Cancer Immunology Research, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA |
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Abstract: | Toll-like receptor 9 (TLR9) senses microbial DNA in the endosomes of plasmacytoid dendritic cells (pDCs) and triggers MyD88-dependent type I interferon (IFN) responses. To better understand TLR9 biology in pDCs, we established a yeast two-hybrid library for the identification of TLR9-interacting proteins. Here, we report that an IFN-inducible protein, phospholipid scramblase 1 (PLSCR1), interacts with TLR9 in pDCs. Knockdown of PLSCR1 expression by siRNA in human pDC cell line led to a 60-70% reduction of IFN-α responses following CpG-ODN (oligodeoxynucleotide) stimulation. Primary pDCs from PLSCR1-deficient mice produced lower amount of type 1 IFN than pDCs from the wild-type mice in response to CpG-ODN, herpes simplex virus and influenza A virus. Following CpG-A stimulation, there were much lower amounts of TLR9 in the early endosomes together with CpG-A in pDCs from PLSCR1-deficient mice. Our study demonstrates that PLSCR1 is a TLR9-interacting protein that plays an important role in pDC''s type 1 IFN responses by regulating TLR9 trafficking to the endosomal compartment. |
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Keywords: | PLSCR1, TLR9, IRF7, pDC, IFN-α signaling |
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