Abstract
Objectives: To analyze the further immunomodulatory effects of endoplasmic reticulum (ER)-stressed umbilical cord-derived mesenchymal stem cells MSCs (UC-MSCs) on rheumatoid arthritis (RA) CD4+CXCR5+ICOS+ T (follicular helper-like T, Tfh) cells.
Methods: MSCs were isolated from umbilical cord and surface markers were identified by flow cytometry. CD4+ T cells were purified from RA patients’ peripheral blood mononuclear cells (PBMCs) using immunomagnetic beads. Thapsigargin (Tg)-stimulated or unstimulated MSCs were co-cultured with RA CD4+ T cells. CD4+CXCR5+ICOS+ T cells were analyzed with fluorescence activating cell sorter (FACS) and major soluble factors secreted by MSCs were detected by qRT-PCR as well as ELISA. Receptors of prostanoid E2 (PGE2), known as EP1-4, on CD4+ T cells were tested with RT-PCR and FACS. Proportion of CD4+CXCR5+ICOS+ T cells was determined after EP2/EP4 antagonists and anti-IL-6R antibody was added into co-cultured system, respectively.
Results: ER-stressed MSCs further down-regulated peripheral CD4+CXCR5+ICOS+ T cells compared with Tg-stimulated MSCs and CD4+ T co-cultured group. PGE2 and IL-6 increased obviously in the supernatants. EP2/EP4 could be detected on CD4+ T cells and frequencies of CD4+CXCR5+ICOS+ T cells were upregulated when EP2 and/or EP4 antagonists rather than anti-IL-6R antibody were added.
Conclusions: ER-stressed MSCs exhibited better inhibition effect on RA CD4+CXCR5+ICOS+ T cells by releasing PGE2, indicating the immunosuppressive effect of MSCs could be enhanced by induction of ER stress.
Compliance with ethical standards
Experiments were approved by the ethical committee of the Second Affiliated Hospital of Dalian Medical University. All study subjects signed written informed consent before participating in the study.
Conflict of interest
None