Published online Nov 14, 2016. doi: 10.3748/wjg.v22.i42.9356
Peer-review started: May 11, 2016
First decision: July 13, 2016
Revised: August 5, 2016
Accepted: August 19, 2016
Article in press: August 19, 2016
Published online: November 14, 2016
Processing time: 185 Days and 20.2 Hours
To investigate the role of regulatory T cell (Treg) subsets in the balance between Treg and T helper 17 (Th17) cells in various tissues from mice with dextran sulfate sodium-induced colitis.
Treg cells, Treg cell subsets, Th17 cells, and CD4+CD25+FoxP3+IL-17+ cells from the lamina propria of colon (LPC) and other ulcerative colitis (UC) mouse tissues were evaluated by flow cytometry. Forkhead box protein 3 (FoxP3), interleukin 17A (IL-17A), and RORC mRNA levels were assessed by real-time PCR, while interleukin-10 (IL-10) and IL-17A levels were detected with a Cytometric Beads Array.
In peripheral blood monocytes (PBMC), mesenteric lymph node (MLN), lamina propria of jejunum (LPJ) and LPC from UC mice, Treg cell numbers were increased (P < 0.05), and FoxP3 and IL-10 mRNA levels were decreased. Th17 cell numbers were also increased in PBMC and LPC, as were IL-17A levels in PBMC, LPJ, and serum. The number of FrI subset cells (CD4+CD45RA+FoxP3low) was increased in the spleen, MLN, LPJ, and LPC. FrII subset cells (CD4+CD45RA-FoxP3high) were decreased among PBMC, MLN, LPJ, and LPC, but the number of FrIII cells (CD4+CD45RA-FoxP3low) and CD4+CD25+FoxP3+IL-17A+ cells was increased. FoxP3 mRNA levels in CD4+CD45RA-FoxP3low cells decreased in PBMC, MLN, LPJ, and LPC in UC mice, while IL-17A and RORC mRNA increased. In UC mice the distribution of Treg, Th17 cells, CD4+CD45RA-FoxP3high, and CD4+CD45RA-FoxP3low cells was higher in LPC relative to other tissues.
Increased numbers of CD4+CD45RA-FoxP3low cells may cause an imbalance between Treg and Th17 cells that is mainly localized to the LPC rather than secondary lymphoid tissues.
Core tip: The exact etiology and pathology of ulcerative colitis (UC) remains unknown. Here we investigated the role of regulatory T cell (Treg) subsets in the balance between Treg and T helper 17 (Th17) cells in various tissues from mice with dextran sulfate sodium-induced colitis. In this study we found that increased numbers of CD4+CD45RA-FoxP3low cells may cause an imbalance between Treg and Th17 cells, which was mainly localized to the lamina propria of colon rather than secondary lymphoid tissues. Based on our findings, lamina propria-resident Treg cells appear to play important roles in shaping local peripheral tolerance and maintaining intestinal homeostasis, and an imbalance of Treg and Th17 cells in the lamina propria of the colon is critical for UC pathogenesis.