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Background: Siglec-1 is a macrophage lectin-like receptor that mediates sialic acid-dependent cellular interactions. Its upregulation on macrophages in autoimmune disease was shown previously to promote inflammation through suppressing the expansion of regulatory T cells (Tregs). Here we investigate the molecular basis for Siglec-1 binding to Tregs using in vitro-induced cells as a model system.
Methods: Glycosylation changes that affect Siglec-1 binding were studied by comparing activated and resting Tregs using RNA-Seq, glycomics, proteomics and binding of selected antibodies and lectins. A proximity labelling and proteomics strategy was used to identify Siglec-1 counter-receptors expressed on activated Tregs.
Results: Siglec-1 binding was strongly upregulated on activated Tregs, but lost under resting conditions. Glycomics revealed changes in N-glycans and glycolipids following Treg activation and we observed changes in expression of multiple 'glycogenes' that could lead to the observed increase in Siglec-1 binding. Proximity labelling of intact, living cells identified 49 glycoproteins expressed by activated Tregs that may function as Siglec-1 counter-receptors. These represent ~5% of the total membrane protein pool and were mainly related to T cell activation and proliferation. We demonstrate that several of these counter-receptors were upregulated following activation of Tregs and provide initial evidence that their altered glycosylation may also be important for Siglec-1 binding.
Conclusions: We provide the first comprehensive analysis of glycan changes that occur in activated Tregs, leading to recognition by the macrophage lectin, Siglec-1 and suppression of Treg expansion. We furthermore provide insights into glycoprotein counter-receptors for Siglec-1 expressed by activated Tregs that are likely to be important for suppressing Treg expansion.
|Number of pages||30|
|Journal||Wellcome Open Research|
|Publication status||Published - 1 Jun 2021|
- Regulatory T cell
- Sialic acid
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Biochemistry, Genetics and Molecular Biology(all)
FingerprintDive into the research topics of 'Activation of regulatory T cells triggers specific changes in glycosylation associated with Siglec-1-dependent inflammatory responses'. Together they form a unique fingerprint.
- 1 Finished
Molecular Dissection of Siglec-Mediated Regulation of Neutrophil Inflammatory Responses (Senior Investigator Award)
1/08/14 → 31/12/19
Fingerprints Proteomics FacilityCentre for Advanced Scientific Technologies
Flow Cytometry and Cell SortingCentre for Advanced Scientific Technologies