Foxp3(+) T cells expressing RORγt represent a stable regulatory T-cell effector lineage with enhanced suppressive capacity during intestinal inflammation.

Foxp3 (forkhead box P3 transcription factor)-expressing regulatory T cells (Tregs) are essential for immunological tolerance, best illustrated by uncontrolled effector T-cell responses and autoimmunity upon loss of Foxp3 expression. Tregs can adopt specific effector phenotypes upon activation, reflecting the diversity of functional demands in the different tissues of the body. Here, we report that Foxp3(+)CD4(+) T cells coexpressing retinoic acid-related orphan receptor-γt (RORγt), the master transcription factor for T helper type 17 (Th17) cells, represent a stable effector Treg lineage. Transcriptomic and epigenetic profiling revealed that Foxp3(+)RORγt(+) T cells display signatures of both Tregs and Th17 cells, although the degree of similarity was higher to Foxp3(+)RORγt(-) Tregs than to Foxp3(-)RORγt(+) T cells. Importantly, Foxp3(+)RORγt(+) T cells were significantly demethylated at Treg-specific epigenetic signature genes such as Foxp3, Ctla-4, Gitr, Eos, and Helios, suggesting that these cells have a stable regulatory rather than inflammatory function. Indeed, adoptive transfer of Foxp3(+)RORγt(+) T cells in the T-cell transfer colitis model confirmed their Treg function and lineage stability in vivo, and revealed an enhanced suppressive capacity as compared with Foxp3(+)RORγt(-) Tregs. Thus, our data suggest that RORγt expression in Tregs contributes to an optimal suppressive capacity during gut-specific immune responses, rendering Foxp3(+)RORγt(+) T cells as an important effector Treg subset in the intestinal system.

Effect of HGF on the apoptosis of rat corpus cavernosum smooth muscle cells induced by TGFß1.

Corpus cavernosum smooth muscle cells (CCSMCs) are important functional cells for penile erection. We evaluated the effect of transforming growth factor ß1 (TGFß1) and hepatocyte growth factor (HGF) on the viability and apoptosis of CCSMCs in vitro. CCSMCs from healthy male Sprague Dawley rats were randomly divided into four groups: a negative control group, a TGFß1 group, a HGF group and a HGF+ TGFß1 group. Differences in cell viability and apoptosis among groups were observed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay and flow cytometry. Western blot was used to detect the change of apoptosis-related proteins. The level of reactive oxygen species (ROS) was detected by colorimetry. In the TGFß1 group, the MTT values were obviously decreased at 12 h, 24 h, 48 h-0.320, 0.383 and 0.432 respectively. However, compared with the normal group, the apoptosis index was markedly increased, reaching 26.86% at the 48-h time point. After TGFß1 treatment, the levels of cleaved caspase-3 and p-Smad2 were increased in the cells, but the levels of Bcl-xL, Bcl-2 and p-Akt were significantly lower. However, HGF co-treatment partially reversed these changes and could decrease the intracellular ROS level while increasing the Akt phosphorylation level. These results indicate that TGFß1 might induce apoptosis of CCSMCs in vitro and that HGF could interfere with the above process through downregulation of apoptosis signalling and oxidative stress reaction.