An imbalance in the lineages of immunosuppressive regulatory T cells (T cells) and the inflammatory T17 subset of helper T cells leads to the development of autoimmune and/or inflammatory disease. Here we found that TAZ, a coactivator of TEAD transcription factors of Hippo signaling, was expressed under T17 cell-inducing conditions and was required for T17 differentiation and T17 cell-mediated inflammatory diseases. TAZ was a critical co-activator of the T17-defining transcription factor RORγt. In addition, TAZ attenuated T cell development by decreasing acetylation of the T cell master regulator Foxp3 mediated by the histone acetyltransferase Tip60, which targeted Foxp3 for proteasomal degradation. In contrast, under T cell-skewing conditions, TEAD1 expression and sequestration of TAZ from the transcription factors RORγt and Foxp3 promoted T cell differentiation. Furthermore, deficiency in TAZ or overexpression of TEAD1 induced T cell differentiation, whereas expression of a transgene encoding TAZ or activation of TAZ directed T17 cell differentiation. Our results demonstrate a pivotal role for TAZ in regulating the differentiation of T cells and T17 cells.

Reactive oxygen species (ROS) production in phagocytes is a major defense mechanism against pathogens. However, the cellular self-protective mechanism against such potential damage from oxidative stress remains unclear. Here we show that the kinases Mst1 and Mst2 (Mst1/2) sense ROS and maintain cellular redox balance by modulating the stability of antioxidant transcription factor Nrf2. Site-specific ROS release recruits Mst1/2 from the cytosol to the phagosomal or mitochondrial membrane, with ROS subsequently activating Mst1/2 to phosphorylate kelch like ECH associated protein 1 (Keap1) and prevent Keap1 polymerization, thereby blocking Nrf2 ubiquitination and degradation to protect cells against oxidative damage. Treatment with the antioxidant N-acetylcysteine disrupts ROS-induced interaction of Mst1/2 with phagosomes or mitochondria, and thereby diminishes the Mst-Nrf2 signal. Consistently, loss of Mst1/2 results in increased oxidative injury, phagocyte ageing and death. Thus, our results identify the Mst-Nrf2 axis as an important ROS-sensing and antioxidant mechanism during an antimicrobial response.

Resveratrol (R-3), a trihydroxy trans-stilbene from grape, inhibits multistage carcinogenesis in animal models. Here we report that 3,5,4'-trimethoxystilbene (MR-3), the permethylated derivative of R-3 was more potent against the growth of human cancer cells (HT-29, PC-3, COLO 205) with estimated IC(50) values of 81.31,42.71, and 6.25 microM, respectively. We further observed that MR-3 induced apoptosis in COLO 205 cells through modulation of mitochondrial functions regulated by reactive oxygen species (ROS). ROS generation occurs in the early stages of MR-3-induced apoptosis, preceding cytochrome-c release, caspase activation, and DNA fragmentation. Significant therapeutic effects were demonstrated in vivo by treating severe combined immune deficiency (SCID) mice bearing COLO 205 tumor xenografts with MR-3 (50 mg/kg ip). Assays on DNA fragmentation and caspase activation were performed and demonstrated that apoptosis occurred in tumor tissues treated with MR-3. The appearance of apoptotic cells, as shown by Hematoxylin and Eosin (H&E) staining, and an increase in p21 and decrease in proliferating cell nuclear antigen (PCNA) protein by immuno-histochemistry were observed in tumor tissues under MR-3 treatment. Our study identifies the novel mechanisms of the antitumor effects of MR-3 and indicates that these results may have significant applications for cancer chemotherapy.

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Tang. CXCL12 promotes atherosclerosis by downregulating ABCA1 expression via the CXCR4/GSK3/-cateninT120/ TCF21 pathway.

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