Super-enhancer receives signals from the extracellular matrix to induce PD-L1-mediated immune evasion via integrin/ BRAF/TAK1/ERK/ETV4 signaling

Objective:PD-L1 and PD-L2 expression levels determine immune evasion and the therapeutic efficacy of immune checkpoint blockade.The factors that drive inducible PD-L1 expression have been extensively studied,but mechanisms that result in constitutive PD-L1 expression in cancer cells are largely unknown.Methods:DNA elements were deleted in cells by CRISPR/Cas9-mediated knockout.Protein function was inhibited by chemical inhibitors.Protein levels were examined by Western blot,mRNA levels were examined by real-time RT-PCR,and surface protein expression was determined by cellular immunofluorescence and flow cytometry.Immune evasion was examined by in vitro T cell-mediated killing.Results:We determined the core regions(chr9:5,496,378–5,499,663)of a previously identified PD-L1L2-super-enhancer(SE).Through systematic analysis,we found that the E26 transformation-specific(ETS)variant transcription factor(ETV4)bound to this core DNA region but not to DNA surrounding PD-L1L2SE.Genetic knockout of ETV4 dramatically reduced the expressions of both PD-L1 and PD-L2.ETV4 transcription was dependent on ERK activation,and BRAF/TAK1-induced ERK activation was dependent on extracellular signaling fromαvβ3 integrin,which profoundly affected ETV4 transcription and PD-L1/L2 expression.Genetic silencing or pharmacological inhibition of components of the PD-L1L2-SE-associated pathway rendered cancer cells susceptible to T cell-mediated killing.Conclusions:We identified a pathway originating from the extracellular matrix that signaled via integrin/BRAF/TAK1/ERK/ETV4 to PD-L1L2-SE to induce PD-L1-mediated immune evasion.These results provided new insights into PD-L1L2-SE activation and pathways associated with immune checkpoint regulation in cancer.

Effect of Different Hormone Combinations on Somatic Embryogenesis in Cotton Cultivar Xinluzao 33(Gossypium hirsutum L.)

[Objective] This study was conducted to evaluate the efficiency of somatic embryogenesis and plant regeneration for an upland cotton cultivar Xinluzao33 under the induction of different hormone combinations and thus to determine the optimal hormone combination. [Method] Calli of Xinluzao33(Gossypium hirsutum L.) were induced from seedling hypocotyl tissue by a range of DK and BK combinations. Embryogenic calli and embryos were induced on callus-inducing medium(CIM) without any hormones. Callus appearance and quality were compared to determine which medium was the optimal for callus induction. Embryogenesis ratio was calculated to determine which medium was the best for somatic embryogenesis and plant regeneration. [Result] Callus induction rate was 100% in all the 12 hormone combinations.The calli were yellow or kelly, and their texture was loose or soft under low concentrations of DK combinations, green or white, variably compact under high concentrations of DK combinations. The calli induced by BK combinations were kelly or green, covering creamy white substance. The best medium for callus induction was DK6(0.05 mg/L 2, 4-D and 0.10 mg/L KT). Embryogenic calli were successfully induced from all the combinations. The efficiency of embryogenic callus induction,embryogenesis, and plantlet regeneration were significantly different among the 12 combinations. The result showed that the embryogenesis ratio was the highest in BK3 combination(0.50 mg/L IBA and 0.50 mg/L KT), 72.86% of embryogenic calli differentiated into somatic embryos after being cultured on CIM for 80 d, and80.93% of the somatic embryos finally regenerated into plants on SEM(somatic embryo induction medium). [Conclusion] These results indicate that hormone combination BK3(0.50 mg/LIBA and 0.50 mg/L KT) was the best medium for somatic embryogenesis and plant regeneration from Xinluzao33.

Conjugation with Acridines Turns Nuclear Localization Sequence into Highly Active Antimicrobial Peptide

The emergence of multidrug-resistant bacteria creates an urgent need for alternative antibiotics with new mechanisms of action. In this study, we synthesized a novel type of antimicrobial agent, Ac r_3-NLS, by conjugating hydrophobic acridines to the N-terminus of a nuclear localization sequence(NLS), a short cationic peptide. To further improve the antimicrobial activity of our agent, dimeric(Acr_3-NLS)_2 was simultaneously synthesized by joining two monomeric Acr_3-NLS together via a disulfide linker. Our results show that Acr_3-NLS and especially(Acr_3-NLS)_2 display signifi cant antimicrobial activity against gramnegative and gram-positive bacteria compared to that of the NLS. Subsequently, the results derived from the study on the mechanism of action demonstrate that Acr_3-NLS and(Acr_3-NLS)_2 can kill bacteria by membrane disruption and DNA binding. The double targets—cell membrane and intracellular DNA—will reduce the risk of bacteria developing resistance to Acr_3-NLS and(Acr_3-NLS)_2. Overall, this study provides a novel strategy to design highly eff ective antimicrobial agents with a dual mode of action for infection treatment.

Advances in the detec

Human health is threatened by foodborne illness and Staphylococcus aureus is a common foodborne pathogenic bacteria.It can cause food poisoning when we are infected,therefore,it is necessary to detect pathogenic bacteria.The virulence genes and detection methods of S.aureus are summarized from literatures.Traditional detection methods are simple but need bacteria enrichment and to prolong detection time.Immunological technology has high specificity,but false positive results are easy to occur in its detection.In recent years,molecular biology methods have developed rapidly,and various PCR techniques have been applied to detect foodborne pathogens.Real-time fluorescent quantitative PCR is more effective than ordinary PCR,while price is expensive when use it,the scope of use is limited.LAMP is a flexible detection method,biosensor and flow cytometry are fast but the cost of detection is high and the price is relatively expensive.