SUMMARY Heightened effector function and prolonged persistence, the key attributes of Th1 and Th17 cells, respectively, are key features of potent anti-tumor T cells. Here, we established ex vivo culture conditions to generate hybrid Th1/17 cells, which persisted long-term in vivo while maintaining their effector function. Using transcriptomics and metabolic profiling approaches, we showed that the enhanced anti-tumor property of Th1/17 cells was dependent on the increased NAD+-dependent activity of the histone deacetylase Sirt1. Pharmacological or genetic inhibition of Sirt1 activity impaired the anti-tumor potential of Th1/17 cells. Importantly, T cells with reduced surface expression of the NADase CD38 exhibited intrinsically higher NAD+, enhanced oxidative phosphorylation, higher glutaminolysis, and altered mitochondrial dynamics that vastly improved tumor control. Lastly, blocking CD38 expression improved tumor control even when using Th0 anti-tumor T cells. Thus, strategies targeting the CD38-NAD+ axis could increase the efficacy of anti-tumor adoptive T cell therapy.

NF-κB is constitutively activated in psoriatic epidermis. However, how activated NF-κB promotes keratinocyte hyperproliferation in psoriasis is largely unknown. Here we report that the NF-κB activation triggered by inflammatory cytokines induces the transcription of microRNA (miRNA) miR-31, one of the most dynamic miRNAs identified in the skin of psoriatic patients and mouse models. The genetic deficiency of miR-31 in keratinocytes inhibits their hyperproliferation, decreases acanthosis and reduces the disease severity in psoriasis mouse models. Furthermore, protein phosphatase 6 (ppp6c), a negative regulator that restricts the G1 to S phase progression, is diminished in human psoriatic epidermis and is directly targeted by miR-31. The inhibition of ppp6c is functionally important for miR-31-mediated biological effects. Moreover, NF-κB activation inhibits ppp6c expression directly through the induction of miR-31, and enhances keratinocyte proliferation. Thus, our data identify NF-κB-induced miR-31 and its target, ppp6c, as critical factors for the hyperproliferation of epidermis in psoriasis.

Allogeneic hematopoietic cell transplantation (HCT) is effective therapy for hematologic malignancies through T cellmediated GVL effects. However, HCT benefits are frequently offset by the destructive GVHD, which is also induced by donor T cells. Naive Th can differentiate into Th1 and Th17 subsets and both can mediate GVHD after adoptive transfer into an allogeneic host. Here we tested the hypothesis that blockade of Th1 and Th17 differentiation is required to prevent GVHD in mice. T cells with combined targeted disruption of T-bet and ROR␥t have defective differentiation toward Th1 and Th17 and skewed differentiation toward Th2 and regulatory phenotypes, and caused ameliorated GVHD in a major MHC-mismatched model of HCT. GVL effects mediated by granzyme-positive CD8 T cells were largely preserved despite T-bet and ROR␥t deficiency. These data indicate that GVHD can be prevented by targeting Th1 and Th17 transcription factors without offsetting GVL activity. (Blood. 2011;118(18):5011-5020) IntroductionSeparation of GVHD from GVL effects is the major challenge of allogeneic hematopoietic cell transplantation (HCT) that is used for the treatment of hematologic malignancies. On Ag stimulation, T-cell precursors can differentiate into distinct functional cell subsets including Th1 and Th17 cells. Understanding the role of each subset in the development of GVHD is critical to develop effective therapy and improve HCT outcome.The cytokine storm caused by the conditioning regimen and Th1-cell cytokines is key to initiating the inflammatory cascade and amplifying immune responses that cause GVHD. 1-3 However, studies using IFN-␥ gene knockout (KO) mice as donors showed that deficiency of IFN-␥ is paradoxically associated with more severe acute GVHD. 4,5 Our group and others found that Th17 cells can augment GVHD in some circumstances, 6,7 and in vitro-generated Th17 cells alone are sufficient to mediate lung and skin GVHD. 8 IFN␥ blockade promotes Th17 differentiation, while IL-17 blockade promotes Th1 differentiation and each blockade alone is ineffective for preventing GVHD,9 suggesting that Th1 and Th17 cells are mutually inhibitory, and that each Th type alone is sufficient to induce GVHD.The transcription factor T-bet is required for the differentiation of Th1 cells 10 and ROR␥t is necessary for Th17 cells. 11 Therefore, we hypothesized that targeted disruption of both T-bet and ROR␥t factors would block Th1 and Th17 differentiation and prevent GVHD. In the current study, we used mice deficient for T-bet, ROR␥t, or both as T-cell donors to test T-bet and ROR␥t as targets to prevent GVHD after allogeneic HCT. Methods Mice Abs and flow cytometryThe following Abs were used for cell-surface staining: anti-CD4-FITC, or -allophycocyanin (L3T4), anti-CD8␣-FITC, -allophycocyanin, -allophycocyanin-cy7 or -Alexa Fluor 700(Ly-2), anti-CD45.1-FITC, or -allophycocyanin (A20), anti-B220-PE (RA3-6B2), anti-H-2K b -FITC, -PE, or -biotin (AF6), purchased from eBioscience; anti-CD4-Pacific Blue (RM4-5) purchased from BD Bioscience...