Bcl-xL mediates interferon-beta secretion by protease-activated receptor 2 deficiency through the mitochondrial permeability transition pore in colorectal cancer metastasis.

Cellular plasticity and immune escape are synergistic drivers of tumor colonization in metastatic organs. Activation of protease-activated receptor 2 (PAR2) signaling promotes metastasis of colorectal carcinoma (CRC). The role of PAR2 in regulating the immune microenvironment and cancer progression remains unclear. We demonstrated that the regulation of liver metastasis by PAR2 requires a competent immune system. PAR2 knockdown enhanced liver infiltration of activated CD8+ T cells prior to metastatic foci formation in an interferon receptor-dependent manner. PAR2 depletion increased interferon (IFN)-ß production via the cGAS-STING and RIG-1 pathways. PAR2 inhibition increased mitochondrial permeability and cytosolic accumulation of mitochondrial DNA, which was reversed by Bcl-xL expression. Strikingly, shRNA against PAR2 with an immune checkpoint blocker (ICB) acted synergistically to suppress liver metastasis. Analysis of single-cell sequence data and 24 paired samples confirmed the regulatory effect of PAR2 on the metastatic immune environment in human CRC. Therefore, PAR2 signaling is involved in stabilizing the mitochondrial membrane and regulating the immune microenvironment through IFN-ß during liver metastasis in CRC. The synergistic effect of the PAR2 inhibitor and ICB provides a potential therapeutic strategy for metastatic CRC treatment.

Pan-cancer analysis identifies PD-L2 as a tumor promotor in the tumor microenvironment.

Background: Programmed cell death protein 1 (PD-1) receptor has two ligands,programmed death-ligand 1 (PD-L1) and PD-L2. When compared with PD-L1, PD-L2 has not received much attention, and its role remains unclear. Methods: The expression profiles of pdcd1lg2 (PD-L2-encoding gene) mRNA and PD-L2 protein were analyzed using TCGA, ICGC, and HPA databases. Kaplan-Meier and Cox regression analyses were used to assess the prognostic significance of PD-L2. We used GSEA, Spearman's correlation analysis and PPI network to explore the biological functions of PD-L2. PD-L2-associated immune cell infiltration was evaluated using the ESTIMATE algorithm and TIMER 2.0. The expressions of PD-L2 in tumor-associated macrophages (TAMs) in human colon cancer samples, and in mice in an immunocompetent syngeneic setting were verified using scRNA-seq datasets, multiplex immunofluorescence staining, and flow cytometry. After fluorescence-activated cell sorting, flow cytometry and qRT-PCR and transwell and colony formation assays were used to evaluate the phenotype and functions of PD-L2+TAMs. Immune checkpoint inhibitors (ICIs) therapy prediction analysis was performed using TIDE and TISMO. Last, a series of targeted small-molecule drugs with promising therapeutic effects were predicted using the GSCA platform. Results: PD-L2 was expressed in all the common human cancer types and deteriorated outcomes in multiple cancers. PPI network and Spearman's correlation analysis revealed that PD-L2 was closely associated with many immune molecules. Moreover, both GSEA results of KEGG pathways and GSEA results for Reactome analysis indicated that PD-L2 expression played an important role in cancer immune response. Further analysis showed that PD-L2 expression was strongly associated with the infiltration of immune cells in tumor tissue in almost all cancer types, among which macrophages were the most positively associated with PD-L2 in colon cancer. According to the results mentioned above, we verified the expression of PD-L2 in TAMs in colon cancer and found that PD-L2+TAMs population was not static. Additionally, PD-L2+TAMs exhibited protumor M2 phenotype and increased the migration, invasion, and proliferative capacity of colon cancer cells. Furthermore, PD-L2 had a substantial predictive value for ICIs therapy cohorts. Conclusion: PD-L2 in the TME, especially expressed on TAMs, could be applied as a potential therapeutic target.

Anesthetic propofol inhibits ferroptosis and aggravates distant cancer metastasis via Nrf2 upregulation.

The impact of anesthetic management on the prognosis of patients with cancer undergoing surgery is controversial. Circulating tumor cells (CTCs) play critical roles during cancer metastasis and can be released in large quantities during surgery. The ferroptosis of CTCs is related to metastasis. Whether anesthetics affect distant metastasis by increasing the survival of CTCs is unknown. To test this hypothesis, mice were inoculated with cancer cells via tail vein injection before treatment with propofol or sevoflurane for 2 h. After 2 weeks, more metastases were observed in the propofol group compared with the sevoflurane and vehicle groups. Then, we used the ferroptosis inhibitor ferrostatin-1 to explore the effect of ferroptosis on metastasis. Similar to propofol, pretreatment with ferrostatin-1 significantly increased CTC survival in mouse lungs at 24 h and the tumor burden at 10 weeks post-inoculation. Moreover, propofol protected cancer cells from RSL3-induced ferroptosis in vitro, as evidenced by decreases in intracellular levels of reactive oxygen species (ROS), lipid peroxide, and ferroptosis markers. Further studies showed that propofol treatment upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target genes, including HO-1, NQO1, and SLC7A11. Finally, the targeted knockdown of Nrf2 abolished the anti-ferroptosis effect of propofol. Collectively, we demonstrated the risk of a specific type of anesthetic, propofol, in promoting cancer cell metastasis through Nrf2-mediated ferroptosis inhibition. These findings may guide the choice of anesthetic for surgical removal of tumors.

Nonlinear relationship between aspartate aminotransferase to alanine aminotransferase ratio and the risk of prediabetes: A retrospective study based on chinese adults.

Objective: Recent evidence has revealed that the aspartate aminotransferase to alanine aminotransferase ratio (AST/ALT ratio) may be closely associated with metabolic syndrome and insulin resistance. However, it is unclear whether the AST/ALT ratio correlates with prediabetes risk. The aim of our study was to examine the association between AST/ALT ratios and the risk of prediabetes among a large cohort of Chinese subjects. Methods: This retrospective cohort study recruited 75204 Chinese adults with normoglycemia at baseline who underwent physical examinations at the Rich Healthcare Group from 2010 to 2016. The AST/ALT ratio at baseline was the target independent variable, and the risk of developing prediabetes during follow-up was the dependent variable. Cox proportional-hazards regression was used to evaluate the independent association between the AST/ALT ratio and prediabetes. This study identified nonlinear relationships by applying a generalized additive model (GAM) and smooth curve fitting. In order to assess the robustness of this study, we performed a series of sensitivity analyses. Moreover, we performed a subgroup analysis to evaluate the consistency of the association in different subgroups. Data from this study have been updated on the DATADRYAD website. Results: The AST/ALT ratio was negatively and independently related to the prediabetes risk among Chinese adults (HR: 0.76, 95% CI: 0.75-0.84, P<0.0001) after adjusting demographic and biochemical covariates. Furthermore, a nonlinear relationship between the AST/ALT ratio and the risk of developing prediabetes was found at an inflection point of 1.50 for the AST/ALT ratio. When the AST/ALT ratio was to the left of the inflection point (AST/ALT ratio ≤ 1.50), the AST/ALT ratio was negatively related to the prediabetes risk (HR:0.70, 95%CI: 0.65-0.76, P<0.0001). In contrast, the relationship tended to be saturated when the AST/ALT ratio was more than 1.50 (HR: 1.01, 95%CI: 0.89-1.15, P=0.8976). Our findings remained robust across a range of sensitivity analyses. Subgroup analysis revealed that other variables did not alter the relationship between the AST/ALT ratio and prediabetes risk. Conclusion: This study revealed that AST/ALT ratio was negatively and independently associated with prediabetes risk among Chinese participants. The relationship between the AST/ALT ratio and prediabetes risk was nonlinear, and AST/ALT ratio ≤ 1.50 was strongly inversely correlated with prediabetes risk.

High-fat diet alleviates colitis by inhibiting ferroptosis via solute carrier family seven member 11.

A high-fat diet (HFD) is reported to exacerbate ulcerative colitis by inducing obesity, which conceals the effect of the diet itself. Ferroptosis, a type of regulated cell death induced by lipid hydroperoxides, has recently been reported in colitis. Here, we aimed to determine whether HFD affects ferroptosis and colitis progression in an obesity-independent manner. We subjected male C57BL/6J mice to either an HFD (60% fat diet) or isocaloric control diet (10% fat diet) for 4 weeks, followed by inducing colitis with 2.5% dextran sulfate sodium (DSS). Compared with the isocaloric control diet, non-obesogenic HFD reduced DSS-induced colonic mucosal injury, as shown by disease activity index, colon thickness, inflammatory infiltrations, and mucosal damage index; however, there were no differences in body weight, Lee's index, and omental fat weight between the two groups. HFD mice exhibited decreased lipid peroxidation and ferroptosis markers expression in colon tissues. Furthermore, a lipid mixture protected gut organoids and normal colonic epithelial cells from RSL3-induced ferroptosis. Mechanistically, the lipid mixture prevented glutathione deficiency by upregulating the cysteine transporter, solute carrier family seven member 11. Collectively, these findings suggest that an HFD ameliorates DSS-induced colitis through ferroptosis repression in an obesity-independent manner and provide new evidence to evaluate the effects of an HFD on colitis.

Host-induced gene silencing reveals the role of Sclerotinia sclerotiorum oxaloacetate acetylhydrolase gene in fungal oxalic acid accumulation and virulence.

Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a devastating necrotrophic pathogen which causes severe yield losses to oilseed production worldwide. Most of efforts at the genetic mitigation of the disease have not been successful. Present investigation was conducted to functionally characterize the effect of down-regulating Ssoah1 during host infection and explore the possibility of boosting host resistance by silencing this gene. We utilized host-induced gene silencing (HIGS) to silence Ssoah1 gene in the S. sclerotiorum fungus. A HIGS based vector was constructed and transformed into Arabidopsis thaliana. The pathogenicity assays in the transgenic A. thaliana lines revealed three T3 transformants with significantly higher resistance to S. sclerotiorum in comparison to untransformed controls. There was a concomitant reduction in expression of Ssoah1 and accumulation of oxalic acid in the necrotic regions of transgenic lines as compared to the non-transgenic controls. Specific Ssoah1-siRNA was highly expressed in HIGS Ssoah1 transgenic lines, as compared with WT and EV plants. The outcomes of oxalic acid estimation revealed that silencing of Ssoah1 results in decreased OA accumulation. The recovered mycelium plugs from HIGS Ssoah1 transgenic lines showed decreased Ssoah1 expression and pathogenesis. These results provide the possibility of using HIGS of Ssoah1 for engineering resistance against S. sclerotiorum.

Effect of Genetic Diversity in Swine Leukocyte Antigen-DRA Gene on Piglet Diarrhea.

The swine leukocyte antigens (SLAs) are the multigene families related to immune responses. Little is known about the effect of the DRA gene on diarrheal disease. This study reported the genetic diversity of the DRA gene in exons 1, 3 and 4 in 290 Chinese Yantai black pigs. No variation was identified in exon 3. In exon 1, three genotypes and two alleles were identified, generated by two single nucleotide polymorphisms (SNPs). In exon 4, there were eight genotypes and five alleles containing seven SNPs were detected with four SNPs being novel SNPs. The low polymorphism found in swine DRA is consistent with the concept that the DRA gene is highly conserved among all mammalian species. Statistical analyses indicated that the genotypes of exon 1 were not significantly associated with piglet diarrhea (p > 0.05); however, genotypes C4C4 (1.80 ± 0.33) and A4E4 (1.66 ± 0.25) of exon 4 were significantly susceptible to diarrhea (p < 0.01). These indicate that the particular genotypes of the DRA gene are susceptible to diarrheal disease, which provides valuable information for disease-resistance breeding in swine.