IL1R1+ cancer-associated fibroblasts drive tumor development and immunosuppression in colorectal cancer.

Fibroblasts have a considerable functional and molecular heterogeneity and can play various roles in the tumor microenvironment. Here we identify a pro-tumorigenic IL1R1+, IL-1-high-signaling subtype of fibroblasts, using multiple colorectal cancer (CRC) patient single cell sequencing datasets. This subtype of fibroblasts is linked to T cell and macrophage suppression and leads to increased cancer cell growth in 3D co-culture assays. Furthermore, both a fibroblast-specific IL1R1 knockout and IL-1 receptor antagonist Anakinra administration reduce tumor growth in vivo. This is accompanied by reduced intratumoral Th17 cell infiltration. Accordingly, CRC patients who present with IL1R1-expressing cancer-associated-fibroblasts (CAFs), also display elevated levels of immune exhaustion markers, as well as an increased Th17 score and an overall worse survival. Altogether, this study underlines the therapeutic value of targeting IL1R1-expressing CAFs in the context of CRC.

IRF4 and BATF are critical for CD8⁺ T-cell function following infection with LCMV.

CD8(+) T-cell functions are critical for preventing chronic viral infections by eliminating infected cells. For healthy immune responses, beneficial destruction of infected cells must be balanced against immunopathology resulting from collateral damage to tissues. These processes are regulated by factors controlling CD8(+) T-cell function, which are still incompletely understood. Here, we show that the interferon regulatory factor 4 (IRF4) and its cooperating binding partner B-cell-activating transcription factor (BATF) are necessary for sustained CD8(+) T-cell effector function. Although Irf4(-/-) CD8(+) T cells were initially capable of proliferation, IRF4 deficiency resulted in limited CD8(+) T-cell responses after infection with the lymphocytic choriomeningitis virus. Consequently, Irf4(-/-) mice established chronic infections, but were protected from fatal immunopathology. Absence of BATF also resulted in reduced CD8(+) T-cell function, limited immunopathology, and promotion of viral persistence. These data identify the transcription factors IRF4 and BATF as major regulators of antiviral cytotoxic T-cell immunity.

Reactive oxygen species delay control of lymphocytic choriomeningitis virus.

Cluster of differentiation (CD)8(+) T cells are like a double edged sword during chronic viral infections because they not only promote virus elimination but also induce virus-mediated immunopathology. Elevated levels of reactive oxygen species (ROS) have been reported during virus infections. However, the role of ROS in T-cell-mediated immunopathology remains unclear. Here we used the murine lymphocytic choriomeningitis virus to explore the role of ROS during the processes of virus elimination and induction of immunopathology. We found that virus infection led to elevated levels of ROS producing granulocytes and macrophages in virus-infected liver and spleen tissues that were triggered by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Lack of the regulatory subunit p47phox of the NADPH oxidase diminished ROS production in these cells. While CD8(+) T cells exhibited ROS production that was independent of NADPH oxidase expression, survival and T-cell function was elevated in p47phox-deficient (Ncf1(-/-)) mice. In the absence of p47phox, enhanced T-cell immunity promoted virus elimination and blunted corresponding immunopathology. In conclusion, we find that NADPH-mediated production of ROS critically impairs the immune response, impacting elimination of virus and outcome of liver cell damage.

[Haponin (eIF1AD) interacts with glyceraldehyde 3-phosphate dehydrogenase in the CHO-K1 cell line].

Haponin (HLDF-alike protein) was previously identified from the human promyelocytic leukemia HL-60 cell line. For the functional study of this protein, we obtained recombinant haponin with an N-terminal hexahistidine tag using a baculovirus expression system. Antibodies against 6xHis-haponin were produced, and the expression of endogenous haponin was demonstrated in mammalian cell lines of different origin. Using affinity chromatography and immunoprecipitation methods, we have shown that in CHO-K1 cells haponin interacts with glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which is one of the vital glycolytic enzymes with a diverse set of noncanonical functions.