Inactivation of Notch signaling reverses the Th17/Treg imbalance in cells from patients with immune thrombocytopenia

Abstract

T helper 17 (Th17) cells and regulatory T (Treg) cells, along with Th1 and Th2 cells, may contribute to the development of immune thrombocytopenia (ITP). The imbalance of Th17/Treg toward Th17 cells has been shown to play a pivotal role in the peripheral immune response. Notch signaling has been implicated in peripheral T-cell activation and effector cell differentiation. However, the role of Th17/Treg in the pathogenesis of ITP and the effect of Notch signaling on Th17/Treg imbalances remain largely elusive in ITP. In vitro, we treated peripheral blood mononuclear cells (PBMCs) from ITP and healthy controls with g-secretase inhibitor (DAPT). Th17 cells and Treg cells were measured by flow cytometry and IL-17, IL-21, and IL-10 secretion by enzyme immunoassay technique. The mRNA expression of Ntoch1, Hes1, Hey1, RORgt, and Foxp3 was investigated by RT-PCR. Cell proliferation and apoptosis were determined by the Cell Counting Kit-8 and apoptosis detection kit. We demonstrated that DAPT was effective in inhibiting mRNA expression of Notch signaling molecules. In untreated cultured PBMCs from ITP patients, we observed elevated Th17 cell and IL-21 levels and RORgt mRNA expression, decreased Treg cells and Foxp3 mRNA expression, and an increased ratio of Th17/Treg and RORgt/Foxp3. After inactivating Notch signal by DAPT, Th17 cells and Th17/Treg ratio were dose dependently decreased and accompanied by the reduction of IL-17 in culture supernatants and RORgt mRNA expression in ITP patients. However, no significant difference was found for Treg cells and Foxp3 mRNA expression, RORgt/Foxp3 ratio, and IL-21 and IL-10 levels after DAPT treatment in ITP patients. We also present evidence that the effect of DAPT inhibition on the Th17 cell response was associated with downregulation of RORgt and IL-17 transcription using human in vitro polarization. In conclusion, our findings highlight the importance of Notch signaling in Th17/Treg imbalances in ITP. Inactivation of Notch signaling might be a potential immunoregulatory strategy in ITP patients.

Correlation between microRNA-21 and expression of Th17 and Treg cells in microenvironment of rats with hepatocellular carcinoma

“…Lv et al reported that miR141-CXCL1-CXCR2 signal-induced Treg recruitment could regulate the metastasis and survival rate of non-small cell lung cancer [11] ; Dong et al found that, in patients with rheumatoid arthritis, there was the correlation between the reduced expression of miR-21 and the imbalance of Th17 and Treg cells [12] . Though this study confirmed the positive correlation between the up-regulated expression of miR-21 and the ratio of Th17/Treg, it is still essential to study the specific regulatory mechanism of molecular biology, in order to provide the new target spots for the diagnosis and treatment of diseases.…”

Notch signalling suppresses regulatory T‐cell function in murine experimental autoimmune uveitis

“…13 With regard to the role of Notch signalling in Treg cells, contradictory results are present in previous studies, including either positive or negative effects on Treg cell homeostasis and function. [14][15][16] However, the exact role of Notch signalling in the modulation of uveitic Treg cells, especially infiltrating Treg cells in uveitic eyes, has not been specified.…”

CCR6 defines a subset of activated memory T cells of Th17 potential in immune thrombocytopenia

“…Conversion of T reg to Th17 cells is regulated partly by epigenetic modifications of transcription factors and signature cytokines [15,33]. The T reg /Th17 ratio may be a useful marker for assessing the severity of diseases in ITP [34]. Interestingly, we found that the CCR6 + Th17/ CCR6 + T reg ratio was higher in ITP patients compared with healthy controls and correlated with the response of treatment, suggesting that the CCR6 + Th17/CCR6 + T reg imbalance might be involved in the pathogenesis of ITP.…”