Specific induction of the unique GPR15 expression in heterogeneous blood lymphocytes by tobacco smoking

Abstract

Purpose: In the peripheral blood, it has been shown that smoking is, to date, the only specific condition leading to an increase in GPR15+ T cells. We, therefore, aimed to characterize GPR15-expressing blood T cells in more detail.

Materials and Methods: The whole transcriptome by RNAseq as a proxy for protein expression was analyzed in GPR15+ and GPR15- T cells. A deep immuno-phenotyping was conducted for the identification of T cell subtypes. Results: The expression of GPR15 seemed to be unique, not concomitantly accompanied with the expression of another protein. According to different T cell subtypes, there is no single cell type prominently represented in GPR15+ T cells. The individually different proportions of GPR15+ cells among each GPR15-expressing T cell subtypes in blood were strongly associated with chronic smoking. Indeed, the frequency of GPR15+ T cell subtypes can be effectively used as a highly convincing biomarker for tobacco smoking. Conclusions: While the chronic smoking-induced enrichment of GPR15+ T cells in blood might indicate a systemic inflammation, by the widespread presence in different T cell subtypes, GPR15 could feature a general impact on maintaining the systemic homeostasis to putatively prevent harm from smoking.

Keywords:

• GPR15
• MAIT
• Th17
• Treg
• smoking

Acknowledgements

We thank Elke Gille and Gulja Willnauer from the Institute of transfusion medicine at the University of Leipzig for their support in provision of data from voluntary blood donors. We thank Kathrin Jäger and Andreas Lösche for performing the flow-cytometric cell sorting at the laboratory of cytometry of the Core Facility at the University of Leipzig.

Disclosure statement

No potential conflict of interest was reported by the authors.