Tissue-Resident Memory CD4+ T Cells Play a Dominant Role in the Initiation of Antitumor Immunity.

Tumor immunology has been studied extensively. Tumor immunology-based cancer immunotherapy has become one of the most promising approaches for cancer treatment. However, one of the fundamental aspects of tumor immunology-the initiation of antitumor immunity-is not fully understood. Compared to that of CD8+ T cells, the effect of CD4+ T cells on antitumor immunity has not been fully appreciated. Using a gene knockout mouse model, the mice of which are deficient in the TCRα repertoire, specifically lacking invariant NKT and mucosal-associated invariant T cells, we found that the deficiency in TCRα repertoire diversity did not affect the antitumor immunity, at least to B16BL6 melanoma and EO771 breast cancer. However, after acquiring thymocytes or splenocytes from wild-type mice, these knockout mice exhibited greatly enhanced and long-lasting antitumor immunity. This enhanced antitumor immunity depended on CD4+ T cells, especially CD4+ tissue-resident memory T (TRM) cells, but not invariant NKT or CD8+ T cells. We also present evidence that CD4+ TRM cells initiate antitumor immunity through IFN-γ, and the process is dependent on NK cells. The CD4+ TRM/NK axis appears to control tumor formation and development by eliminating tumor cells and modulating the tumor microenvironment. Taken together, our results demonstrated that CD4+ TRM cells play a dominant role in the initiation of antitumor immunity.

Chronic Alcohol Consumption Enhances Skeletal Muscle Wasting in Mice Bearing Cachectic Cancers: The Role of TNFα/Myostatin Axis.

BACKGROUND: Chronic alcohol consumption enhances cancer-associated cachexia, which is one of the major causes of decreased survival. The precise molecular mechanism of how alcohol consumption enhances cancer-associated cachexia, especially skeletal muscle loss, remains to be elucidated. METHODS: We used a mouse model of chronic alcohol consumption, in which 20% (w/v) alcohol was provided as sole drinking fluid, and Lewis lung carcinoma to study the underlying mechanisms. RESULTS: We found that alcohol consumption up-regulated the expression of MAFbx, MuRF-1, and LC3 in skeletal muscle, suggesting that alcohol enhanced ubiquitin-mediated proteolysis and LC3-mediated autophagy. Alcohol consumption enhanced phosphorylation of Smad2/3, p38, and ERK and decreased the phosphorylation of FOXO1. These are the signaling molecules governing protein degradation pathways. Moreover, alcohol consumption slightly up-regulated the expression of insulin receptor substrate-1, did not affect phosphatidylinositol-3 kinase, but decreased the phosphorylation of Akt and mammalian target of rapamycin (mTOR), and down-regulated the expression of Raptor and p70 ribosomal kinase S6 kinase, suggesting that alcohol impaired protein synthesis signaling pathway in skeletal muscle of tumor-bearing mice. Alcohol consumption enhanced the expression of myostatin in skeletal muscle, plasma, and tumor, but did not affect the expression of myostatin in non-tumor-bearing mice. In TNFα knockout mice, the effects of alcohol-enhanced expression of myostatin and protein degradation-related signaling molecules, and decreased protein synthesis signaling in skeletal muscle were abolished. Consequently, alcohol consumption neither affected cancer-associated cachexia nor decreased the survival of TNFα KO mice bearing cachectic cancer. CONCLUSIONS: Chronic alcohol consumption enhances cancer-associated skeletal muscle loss through suppressing Akt/mTOR-mediated protein synthesis pathway and enhancing protein degradation pathways. This process is initiated by TNFα and mediated by myostatin.

Effects of TNF-α deletion on iNKT cell development, activation, and maturation in the steady-state and chronic alcohol-consuming mice.

Cytokines play critical roles in regulating iNKT cell development, activation, and maturation. TNF-α co-occurs with iNKT cells in steady-state and many disease conditions. How TNF-α affects iNKT cell function has not been thoroughly investigated. It was found that chronic alcohol consumption enhanced iNKT cell activation and maturation. The underlying mechanism is not known. Herein, a TNF-α KO mouse model was used to address these issues. It was found that the depletion of TNF-α mitigated alcohol consumption-enhanced iNKT cell activation and maturation. In steady-state, depletion of TNF-α did not affect the frequency of iNKT cells in the thymus and spleen but decreased iNKT cells in the liver and increased liver iNKT cell apoptosis. The portion of stage-2 immature iNKT cells increased, stage-3 mature iNKT cells decreased in the thymus of TNF-α KO mice, suggesting that depletion of TNF-α impairs iNKT cell development and maturation. The percentage of CD69+ iNKT cells was significantly lower in the thymus, spleen, and liver of TNF-α KO mice compared to their wild-type littermates, suggesting that depletion of TNF-α inhibits iNKT cell activation. Moreover, the percentage of splenic IL-4- and IFN-γ-producing iNKT cells was significantly lower in TNF-α KO mice than in their wild-type littermates. The depletion of TNF-α increased PLZF+ iNKT cells in the thymus and down-regulated the expression of CD122 on iNKT cells. Collectively, these results support that TNF-α plays a vital role in the regulation of iNKT cell development, activation, and maturation, and alcohol consumption enhances iNKT cell activation and maturation through TNF-α.

SucA-dependent uptake of sucrose across the outer membrane of Caulobacter crescentus.

Caulobacter crescentus is an aquatic Gram-negative bacterium that lives in nutrient-poor environments. Like several other aquatic and phytopathogenic bacteria, Caulobacter cells have a relatively large number of genes predicted to encode TonB-dependent receptors (TBDRs). TBDRs transport nutrients across the outer membrane using energy from the proton motive force. We identified one TBDR gene, sucA, which is situated within a cluster of genes predicted to encode a lacI-family transcription factor (sucR), amylosucrase (sucB), fructokinase (sucC), and an inner membrane transporter (sucD). Given its genomic neighborhood, we proposed that sucA encodes a transporter for sucrose. Using RT-qPCR, we determined that expression of sucABCD is strongly induced by sucrose in the media and repressed by the transcription factor, SucR. Furthermore, cells with a deletion of sucA have a reduced uptake of sucrose. Although cells with a non-polar deletion of sucA can grow with sucrose as the sole carbon source, cells with a polar deletion that eliminates expression of sucABCD cannot grow with sucrose as the sole carbon source. These results show that the suc locus is essential for sucrose utilization while SucA functions as one method of sucrose uptake in Caulobacter crescentus. This work sheds light on a new carbohydrate utilization locus in Caulobacter crescentus.

Therapeutic effects of recombinant human S100A6 and soluble receptor for advanced glycation end products(sRAGE) on CCl4-induced liver fibrosis in mice.

Hepatic fibrosis is a pathological process in which extracellular matrix excessively aggregates in an injured liver. Research on hepatic fibrosis is expanding, however, much information in this process is still unclear. Here, we examined the gene expression changes within the process of liver fibrosis, providing the first evidence that secreted S100A6 is a critical contributor. We discovered that expression of the S100 family is highly correlated with CCl4-induced liver fibrosis and post self-recovery in mice. Recombinant human S100A6 (rhS100A6) introduced to CCl4-induced mice was found to enhance liver fibrosis through the promotion of activated hepatic stellate cell (HSC) proliferation. More importantly, we showed that rhS100A6 can induce cell cycle transition from S to G2 stage and significantly elevate the level of ERK phosphorylation in the MARK pathway. In contrast to rhS100A6, recombinant human and soluble receptor for advanced glycation end products (sRAGE), a natural antagonist of the S100/RAGE pathway, was found to have a preventative effect on liver fibrosis in CCl4-induced mice. In conclusion, our study supports that S100A6 could be a novel therapeutic in liver fibrosis and its receptor antagonist, sRAGE, proofed to be effective for the treatment of liver fibrosis.