BPTF Is Essential for T Cell Homeostasis and Function

Bromodomain PHD Finger Transcription Factor (BPTF), a ubiquitously expressed ATP-dependent chromatin-remodeling factor, is critical for epigenetically regulating DNA accessibility and gene expression. While BPTF is important for the development of thymocytes, its function in mature T cells remains largely unknown. By specifically deleting BPTF from late DN3/DN4 stage of developing T cells, we found that BPTF was critical for the homeostasis of T cells via a cell intrinsic manner. In addition, BPTF was essential for the maintenance and function of Treg cells. Treg cell-specific BPTF deletion led to reduced Foxp3 expression, increased lymphocyte infiltration in the non-lymphoid organs and a systemic autoimmune syndrome. These findings therefore reveal a vital role for BPTF in T and Treg cell function and immune homeostasis

MICA/B expression is inhibited by unfolded protein response and associated with poor prognosis in human hepatocellular carcinoma

BackgroundMICA/B are major ligands for NK cell activating receptor NKG2D and previous studies showed that the serum level of soluble MICA (sMICA) is an independent prognostic factor for advanced human hepatocellular carcinoma. However, the correlation between cellular MICA/B expression pattern and human hepatocellular carcinoma progression has not been well explored. The unfolded protein response is one of the main causes of resistance to chemotherapy and radiotherapy in tumor cells. However, whether the UPR in HCC could regulate the expression levels of MICA/B and affect the sensitivity of HCC cells to NK cell cytolysis has not been established yet.MethodsMICA/B expression pattern was evaluated by immunohistochemistry and Kaplan-Meier survival analysis was done to explore the relationship between MICA/B expression level and patient survival. The protein and mRNA expression levels of MICA/B in SMMC7721 and HepG2 cells treated by tunicamycin were evaluated by flow cytometry, Western Blot and RT-PCR. The cytotoxicity analysis was performed with the CytoTox 96 Non-Radioactive LDH Cytotoxicity Assay.ResultsMICA/B was highly expressed in human hepatocellular carcinoma and the expression level was significantly and negatively associated with tumor-node metastasis (TNM) stages. Patients with low level of MICA/B expression showed a trend of shorter survival time. The unfolded protein response (UPR) downregulated the expression of MICA/B. This decreased protein expression occurred via post-transcriptional regulation and was associated with proteasomal degradation. Moreover, decreased expression level of MICA/B led to the attenuated sensitivity of human HCC to NK cell cytotoxicity.ConclusionThese new findings of the connection of MICA/B, UPR and NK cells may represent a new concrete theory of NK cell regulation in HCC, and suggest that targeting this novel NK cell-associated immune evasion pathway may be meaningful in treating patients with HCC.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-014-0076-7) contains supplementary material, which is available to authorized users