Salmonella exploits HLA-B27 and host unfolded protein responses to promote intracellular replication
Abstract
Objective Salmonella enterica infections can lead to Reactive Arthritis (ReA), which can exhibit an association with human leucocyte antigen (HLA)-B*27:05, a molecule prone to misfolding and initiation of the unfolded protein response (UPR). This study examined how HLA-B*27:05 expression and the UPR affect the Salmonella life-cycle within epithelial cells. Methods Isogenic epithelial cell lines expressing two copies of either HLA-B*27:05 and a control HLA-B*35:01 heavy chain (HC) were generated to determine the effect on the Salmonella infection life-cycle. A cell line expressing HLA-B*27:05.HC physically linked to the light chain beta-2-microglobulin and a specific peptide (referred to as a single chain trimer, SCT) was also generated to determine the effects of HLA-B27 folding status on S. enterica life-cycle. XBP-1 venus and AMP dependent Transcription Factor (ATF6)-FLAG reporters were used to monitor UPR activation in infected cells. Triacin C was used to inhibit de novo lipid synthesis during UPR, and confocal imaging of ER tracker stained membrane allowed quantification of glibenclamide-associated membrane. Results S. enterica demonstrated enhanced replication with an altered cellular localisation in the presence of HLA-B*27:05.HC but not in the presence of HLA-B*27:05.SCT or HLA-B*35:01. HLA-B*27:05.HC altered the threshold for UPR induction. Salmonella activated the UPR and required XBP-1 for replication, which was associated with endoreticular membrane expansion and lipid metabolism. Conclusions HLA-B27 misfolding and a UPR cellular environment are associated with enhanced Salmonella replication, while Salmonella itself can activate XBP-1 and ATF6. These data provide a potential mechanism linking the life-cycle of Salmonella with the physicochemical properties of HLA-B27 and cellular events that may contribute to ReA pathogenesis. Our observations suggest that the UPR pathway maybe targeted for future therapeutic intervention.
Citation
Antoniou , A N , Lenart , I , Kriston-Vizi , J , Iwawaki , T , Turmaine , M , McHugh , K , Ali , S , Blake , N , Bowness , P , Bajaj-Elliott , M , Gould , K , Nesbeth , D & Powis , S J 2019 , ' Salmonella exploits HLA-B27 and host unfolded protein responses to promote intracellular replication ' , Annals of the Rheumatic Diseases , vol. 78 , no. 1 , 213532 , pp. 74–82 . https://doi.org/10.1136/annrheumdis-2018-213532
Publication
Annals of the Rheumatic Diseases
Status
Peer reviewed
ISSN
0003-4967Type
Journal article
Rights
© Author(s) (or their employer(s)) 2018. This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See: http://creativecommons.org/licenses/by-nc/4.0/.
Description
A.N.A was funded by ARUK Fellowships Non-Clinical Career Development Fellowship Ref No: 18440. I.L. was funded by an ARUK PhD studentship Ref No: 17868. A.N.A and S.J.P were also in part funded by ARUK (grant 21261)Collections
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