Priming with LSD1 inhibitors promotes the persistence and antitumor effect of adoptively transferred T cells.

The antitumor efficacy of adoptively transferred T cells is limited by their poor persistence, in part due to exhaustion, but the underlying mechanisms and potential interventions remain underexplored. Here, we show that targeting histone demethylase LSD1 by chemical inhibitors reshapes the epigenome of in vitro activated and expanded CD8+ T cells, and potentiates their antitumor efficacy. Upon T cell receptor activation and IL-2 signaling, a timely and transient inhibition of LSD1 suffices to improve the memory phenotype of mouse CD8+ T cells, associated with a better ability to produce multiple cytokines, resist exhaustion, and persist in both antigen-dependent and -independent manners after adoptive transfer. Consequently, OT1 cells primed with LSD1 inhibitors demonstrate an enhanced antitumor effect in OVA-expressing solid tumor models implanted in female mice, both as a standalone treatment and in combination with PD-1 blockade. Moreover, priming with LSD1 inhibitors promotes polyfunctionality of human CD8+ T cells, and increases the persistence and antitumor efficacy of human CD19-CAR T cells in both leukemia and solid tumor models. Thus, pharmacological inhibition of LSD1 could be exploited to improve adoptive T cell therapy.

CPT1A induction following epigenetic perturbation promotes MAVS palmitoylation and activation to potentiate antitumor immunity.

Targeting epigenetic regulators to potentiate anti-PD-1 immunotherapy converges on the activation of type I interferon (IFN-I) response, mimicking cellular response to viral infection, but how its strength and duration are regulated to impact combination therapy efficacy remains largely unknown. Here, we show that mitochondrial CPT1A downregulation following viral infection restrains, while its induction by epigenetic perturbations sustains, a double-stranded RNA-activated IFN-I response. Mechanistically, CPT1A recruits the endoplasmic reticulum-localized ZDHHC4 to catalyze MAVS Cys79-palmitoylation, which promotes MAVS stabilization and activation by inhibiting K48- but facilitating K63-linked ubiquitination. Further elevation of CPT1A incrementally increases MAVS palmitoylation and amplifies the IFN-I response, which enhances control of viral infection and epigenetic perturbation-induced antitumor immunity. Moreover, CPT1A chemical inducers augment the therapeutic effect of combined epigenetic treatment with PD-1 blockade in refractory tumors. Our study identifies CPT1A as a stabilizer of MAVS activation, and its link to epigenetic perturbation can be exploited for cancer immunotherapy.

Ezh2 competes with p53 to license lncRNA Neat1 transcription for inflammasome activation.

Inflammasome contributes to the pathogenesis of various inflammatory diseases, but the epigenetic mechanism controlling its activation remains elusive. Here, we found that the histone methyltransferase Ezh2 mediates the activation of multiple types of inflammasomes in macrophages/microglia independent of its methyltransferase activity and thus promotes inflammasome-related pathologies. Mechanistically, Ezh2 functions through its SANT2 domain to maintain the enrichment of H3K27 acetylation in the promoter region of the long noncoding RNA (lncRNA) Neat1, thereby promoting chromatin accessibility and facilitating p65-mediated transcription of Neat1, which is a critical mediator of inflammasome assembly and activation. In addition, the tumour suppressor protein p53 competes with Ezh2 for the same binding region in the Neat1 promoter and thus antagonises Ezh2-induced Neat1 transcription and inflammasome activation. Therefore, loss of Ezh2 strongly promotes the binding of p53, which recruits the deacetylase SIRT1 for H3K27 deacetylation of the Neat1 promoter and thus suppresses Neat1 transcription and inflammasome activation. Overall, our study demonstrates an epigenetic mechanism involved in modulating inflammasome activation through an Ezh2/p53 competition model and highlights a novel function of Ezh2 in maintaining H3K27 acetylation to support lncRNA Neat1 transcription.

Recombinant HcGAPDH Protein Expressed on Probiotic Bacillus subtilis Spores Protects Sheep from Haemonchus contortus Infection by Inducing both Humoral and Cell-Mediated Responses.

Probiotic Bacillales are effective in controlling pathogens. Live probiotic bacteria improve the composition of the gastrointestinal microbiota, leading to a reduction in pathogen colonization. However, it remains largely unknown how probiotics regulate the host's immunologic responses and protect the host from parasitic infection. In this study, we addressed whether Bacillales were effective against Haemonchus contortus, a parasitic nematode that infects small ruminants worldwide. Using 16S rRNA sequencing, we found that Bacillales were largely depleted in the abomasal microbiota of sheep infected with H. contortus We constructed a recombinant Bacillus subtilis named rBS CotB-HcG that express the glyceraldehyde-3-phosphate dehydrogenase of H. contortus (HcGAPDH) on its spore surface using the Bacillus subtilis spore coat protein B (CotB) as a carrier. Mice receiving rBS CotB-HcG orally showed strong Th1-dominated immune responses. More importantly, sheep administered BS CotB-HcG per os showed increasing proliferation of the peripheral blood mononucleates, elevated anti-HcGAPDH IgG in sera, and higher anti-HcGAPDH sIgA in the intestinal mucus than the control sheep. The average weight gain of H. contortus-infected sheep treated with rBS CotB-HcG (Hc+rBS CotB-HcG ) was 48.73% greater than that of unvaccinated sheep. Furthermore, these Hc+rBS CotB-HcG sheep had fewer eggs per gram of feces by 84.1% and adult worms by 71.5%. They also demonstrated greatly lessened abomasal damage by H. contortus with an abundance of probiotic species in the abomasal microbiota. Collectively, our data unequivocally demonstrate the protective roles of CotB-HcGAPDH-expressing B. subtilis spores in against H. contortus infection and showed great potential of using probiotic-based strategy in controlling parasitic nematodes of socioeconomic importance in general.IMPORTANCE Initial analyses of the abomasal microbiota of sheep using 16S rRNA sequencing suggested that probiotic bacteria played a protective role in against H. contortus infection. A recombinant Bacillus subtilis expressing a fusion protein CotB-HcGAPDH on its spore's surface induced strong Th1 immune response in a murine model. The same probiotic recombinant, upon only one oral application, protected sheep against H. contortus infection by reducing egg shedding and decreasing adult worm loads of the parasite and increasing body weight gain of infected sheep. Both Th1 and Th2 immune responses were evident in these immunized sheep.