Targeting inflammation with chimeric antigen receptor macrophages using a signal switch

Chimeric antigen receptor-T (CAR-T) cell immunotherapy has shown great success in clinical cancer, bringing hope that applying CAR strategies to other immune cell lineages may be beneficial in other clinical settings. We developed a CAR-macrophage (CAR-M) that recognizes the major inflammatory molecule TNF-α and activates an intracellular IL-4 signaling pathway, thereby programming engineered macrophages for an anti-inflammatory function. Infused CAR-Ms switched to an anti-inflammatory phenotype in inflamed kidney and attenuated kidney ischemia reperfusion injury (IRI). The anti-inflammatory phenotype of infused CAR-Ms switched off during the recovery phase of kidney IRI, coinciding with the disappearance of TNF-α. In Adriamycin-induced nephropathy, a model of chronic kidney disease, infused CAR-Ms maintained an anti-inflammatory phenotype for several weeks in response to sustained high levels of TNF-α, resulting in an anti-inflammatory milieu that improved kidney function and structure. CAR-Ms also effectively reduced tissue injury in another organ, liver. The CAR-M design, utilizing signal switching, holds promise for the treatment of a broad range of acute and chronic inflammatory diseases.