Immune-enhancing neutrophils reprogrammed by subclinical low-dose endotoxin in cancer treatment.

Despite the re-emergence of the pioneering "Coley's toxin" concept in anti-cancer immune therapies highlighted by check-point inhibitors and CAR-T approaches, fundamental mechanisms responsible for the immune-enhancing efficacy of low-dose "Coley's toxin" remain poorly understood. This study examines the novel reprogramming of immune-enhancing neutrophils by super-low dose endotoxin conducive for anti-cancer therapies. Through integrated analyses including scRNAseq and functional characterizations, we examined the efficacy of reprogrammed neutrophils in treating experimental cancer. We observed that neutrophils trained by super-low dose endotoxin adopt a potent immune-enhancing phenotype characterized by CD177loCD11bloCD80hiCD40hiDectin2hi. Both murine and human neutrophils trained by super-low dose endotoxin exhibit relieved suppression of adaptive T cells as compared to un-trained neutrophils. Functionally, neutrophils trained by super-low dose endotoxin can potently reduce tumor burden when transfused into recipient tumor-bearing mice. Mechanistically, Super-low dose endotoxin enables the generation of immune-enhancing neutrophils through activating STAT5 and reducing innate suppressor IRAK-M. Together, our data clarify the long-held mystery of "Coley's toxin" in rejuvenating anti-tumor immune defense, and provide a proof-of-concept in developing innate neutrophil-based anti-tumor therapeutics.

Monocytes reprogrammed by 4-PBA potently contribute to the resolution of inflammation and atherosclerosis.

Background: Chronic inflammation initiated by inflammatory monocytes underlies the pathogenesis of atherosclerosis. However, approaches that can effectively resolve chronic low-grade inflammation targeting monocytes are not readily available. The small chemical compound 4-phenylbutyric acid (4-PBA) exhibits broad anti-inflammatory effects in reducing atherosclerosis. Selective delivery of 4-PBA reprogrammed monocytes may hold novel potential in providing targeted and precision therapeutics for the treatment of atherosclerosis. Methods: Systems analyses integrating single-cell RNA-sequencing and complementary immunological approaches characterized key resolving characteristics as well as defining markers of reprogrammed monocytes trained by 4-PBA. Molecular mechanisms responsible for monocyte reprogramming was assessed by integrated biochemical and genetic approaches. The inter-cellular propagation of homeostasis resolution was evaluated by co-culture assays with donor monocytes trained by 4-PBA and recipient naïve monocytes. The in vivo effects of monocyte resolution and atherosclerosis prevention by 4-PBA were assessed with the high fat diet-fed ApoE -/- mouse model with i.p. 4-PBA administration. Furthermore, the selective efficacy of 4-PBA trained monocytes were examined by i.v. transfusion of ex vivo trained monocytes by 4-PBA into recipient high fat diet-fed ApoE -/- mice. Results: In this study, we found that monocytes can be potently reprogrammed by 4-PBA into an immune-resolving state characterized by reduced adhesion and enhanced expression of anti-inflammatory mediator CD24. Mechanistically, 4-PBA reduced the expression of ICAM-1 via reducing peroxisome stress and attenuating SYK-mTOR signaling. Concurrently, 4-PBA enhanced the expression of resolving mediator CD24 through promoting PPARγ neddylation mediated by TOLLIP. 4-PBA trained monocytes can effectively propagate anti-inflammation activity to neighboring monocytes through CD24. Our data further demonstrated that 4-PBA trained monocytes effectively reduce atherosclerosis pathogenesis when administered in vivo . Conclusion: Our study describes a robust and effective approach to generate resolving monocytes, characterizes novel mechanisms for targeted monocyte reprogramming, and offers a precision-therapeutics for atherosclerosis based on delivering reprogrammed resolving monocytes.