GAPDH Overexpression in the T Cell Lineage Promotes Angioimmunoblastic T Cell Lymphoma through an NF-κB-Dependent Mechanism.

GAPDH is emerging as a key player in T cell development and function. To investigate the role of GAPDH in T cells, we generated a transgenic mouse model overexpressing GAPDH in the T cell lineage. Aged mice developed a peripheral Tfh-like lymphoma that recapitulated key molecular, pathological, and immunophenotypic features of human angioimmunoblastic T cell lymphoma (AITL). GAPDH induced non-canonical NF-κB pathway activation in mouse T cells, which was strongly activated in human AITL. We developed a NIK inhibitor to reveal that targeting the NF-κB pathway prolonged AITL-bearing mouse survival alone and in combination with anti-PD-1. These findings suggest the therapeutic potential of targeting NF-κB signaling in AITL and provide a model for future AITL therapeutic investigations.

Inhibition of Noninfectious Uveitis Using Intravenous Administration of Collagen II-Specific Type 1 Regulatory T Cells.

PURPOSE: To evaluate the therapeutic potential of Col-Treg, a collagen II-specific type 1 regulatory T-cell immunotherapy for the treatment of noninfectious uveitis (NIU). METHODS: Col-Treg cells were produced from collagen II-specific T cell receptor (TCR) transgenic mice or peripheral blood of healthy donors. Phenotypic characterization was performed by flow cytometry, and cytokine secretion was evaluated with Flowcytomix or ELISA. In vitro functional characterization included ATP hydrolysis, cytotoxicity, and contact-independent T-cell suppression and plasticity assays. Col-Treg migration was assessed by quantitative PCR specific to Col-Treg TCR. Col-Treg cells were administered intravenously in mice displaying experimental autoimmune uveitis (EAU) induced by interphotoreceptor retinoid-binding protein (IRBP) immunizations. Efficacy of Col-Treg was assessed by ophthalmology, histology, and immunohistochemistry. RESULTS: Mice Col-Treg cells displayed identity features of type 1 Treg cells with expression of CD25, FoxP3, low surface expression of CD127, and cytokine secretion profile (IL-10(high), IL-4(low), IFN-γ(int)). In vitro functional assays demonstrated Col-Treg suppressive capacity via soluble factor-dependent immunosuppression, cytotoxicity, and ATP hydrolysis. Col-Treg cells expressed granzyme B, CD39, and glucocorticoid-induced TNF-related protein (GITR). Administration of Col-Treg in EAU mice inhibited clinical and morphologic signs of uveitis and decreased ocular leukocyte infiltration. Col-Treg cells homed in the ocular tissues 24 hours after intravenous injection. Human Col-Treg cells were comparable to mice Col-Treg cells in identity and function and did not show the capacity to differentiate into Th17 cells in vitro. CONCLUSIONS: These results demonstrate the therapeutic potential of Col-Treg cells as a targeted approach for the treatment of NIU and the feasibility of translating this approach to the human clinical setting.

Caloric restriction modulates Mcl-1 expression and sensitizes lymphomas to BH3 mimetic in mice.

Caloric restriction (CR) is proposed to decrease tumorigenesis through a variety of mechanisms including effects on glycolysis. However, the understanding of how CR affects the response to cancer therapy is still rudimentary. Here, using the Eµ-Myc transgenic mouse model of B-cell lymphoma, we report that by reducing protein translation, CR can reduce expression of the prosurvival Bcl-2 family member Mcl-1 and sensitize lymphomas to ABT-737-induced death in vivo. By using Eµ-Myc lymphoma cells lacking p53, we showed that CR mimetics such as 2-deoxyglucose led to a decrease in Mcl-1 expression and sensitized lymphoma cells to ABT-737-induced death independently of p53. In keeping with this, Eµ-Myc lymphoma cells lacking the BH3-only proapoptotic members Noxa, Puma, or Bim were also sensitized by CR mimetics to ABT-737-induced death. Remarkably, neither the loss of both Puma and Noxa, the loss of both Puma and Bim, nor the loss of all three BH3-only proteins prevented sensitization to ABT-737 induced by CR mimetics. Thus, CR can influence Mcl-1 expression and sensitize cells to BH3 mimetic-induced apoptosis, independently of the main BH3-only proteins and of p53. Exploiting this may improve the efficiency of, or prevent resistance to, cancer therapy.

Combination of glycolysis inhibition with chemotherapy results in an antitumor immune response.

Most DNA-damaging agents are weak inducers of an anticancer immune response. Increased glycolysis is one of the best-described hallmarks of tumor cells; therefore, we investigated the impact of glycolysis inhibition, using 2-deoxyglucose (2DG), in combination with cytotoxic agents on the induction of immunogenic cell death. We demonstrated that 2DG synergized with etoposide-induced cytotoxicity and significantly increased the life span of immunocompetent mice but not immunodeficient mice. We then established that only cotreated cells induced an efficient tumor-specific T-cell activation ex vivo and that tumor antigen-specific T cells could only be isolated from cotreated animals. In addition, only when mice were immunized with cotreated dead tumor cells could they be protected (vaccinated) from a subsequent challenge using the same tumor in viable form. Finally, we demonstrated that this effect was at least partially mediated through ERp57/calreticulin exposure on the plasma membrane. These data identify that the targeting of glycolysis can convert conventional tolerogenic cancer cell death stimuli into immunogenic ones, thus creating new strategies for immunogenic chemotherapy.

Severe thymic atrophy in a mouse model of skin inflammation accounts for impaired TNFR1 signaling.

Transgenic mice expressing the caspase-cleaved form of the tyrosine kinase Lyn (LynΔN) develop a TNFα-dependent skin disease that accurately recapitulates human psoriasis. Participation of lymphocytes in this disease was confirmed by backcrossing LynΔN mice on a Rag-1 deficient background. The present study was therefore conducted to analyze whether modification of lymphocyte homeostasis does occur and participate in the phenotype of LynΔN mice. We show here that LynΔN mice consistently exhibit thymic atrophy that correlates with both a net decrease in the CD4+/CD8+ Double Positive (DP) and an increase in Single Positive (SP) thymocyte sub-populations, but also display an increase of splenic mature B cell. Interestingly, a normal immune phenotype was rescued in a TNFR1 deficient background. Finally, none of these immune alterations was detected in newborn mice before the onset of inflammation. Therefore, we conclude that chronic inflammation can induce thymic atrophy and perturb spleen homeostasis in LynΔN mice through the increased production of TNFα, LTß and TNFR1 signaling.