Á. F. Kovács1, N. Fekete1, L. Kőhidai1, E. I. Buzás1, É. Pállinger1
1 Department of Genetics, Cell- and Immunobiology, Semmelweis University, Budapest
Introduction: Regulatory T cell (Treg) signature is composed of cell clusters of discrete states dispersed in a continuum gravitating around four different well-definable functional poles. The cell number and function of memory Treg cells is of key question, as these cells promote reproductive fitness during human pregnancy by reinforcing immune tolerance against fetal antigens.
The aim of our study was to examine the role of trophoblast associated HSPE1 in Treg differentiation and its influence on the functional states.
Methods: Flow cytometry was applied for determination of HSPE1 expression in BeWo trophoblastic cell line and BeWo-derived extracellular vesicles (EVs). EVs binding to lymphocytes and EV-induced IL6Rα expression and cytokine production were quantified by FACS. Treg cells were differentiated from CD4+ T lymphocytes in the presence or absence of EVs. Gene expression of HSPE1 in circulating lymphocytes was evaluated by qPCR. Single-cell Treg and naïve T cell sequencing data were obtained from 10x Genomics repository and analysed with Python based Scanpy toolkit.
Results: HSPE1 could be detected in EVs. BeWo-derived EVs bound to CD4+ T cells and downregulated IL6Rα and induced IL-10 production. BeWo EVs in the presence of IL-6 induced the expression of HSPE1 in lymphocytes. Differentiated Treg subpopulations were identified with single-cell transcriptomic data. We defined 4 in-house panels for the Treg cell subtype identification. Two clusters of memory Treg were identified. Among Treg cells, HSPE1 shows a cluster-dependent expression pattern; the memory subtype expressing the highest levels.
Conclusion: By our in silico approach, we defined 4 gene panels which provide a good identification tool for the different Treg cells subtypes. Single-cell analysis shows a Treg cell subtype-specific signature of HSPE1 expression. Our results raise the possibility that BeWo-derived HSPE1+ EVs may be an inducing factor for Treg cell differentiation and memory Treg expansion.
Doctoral School of Molecular Medicine
Program: Basis of Human Molecular Genetics and Gene Diagnostics
Supervisor: Éva Pállinger