CRISPRa engineered Elite macrophages enable adoptive cell therapy for rheumatoid arthritis

Rheumatoid arthritis (RA) is a poly-articular systemic autoimmune disorder characterized by infiltration of immune cells, synovial hyperplasia and joint destruction. Macrophages (MΦs) can polarize into either pro-inflammatory M1 or anti-inflammatory M2 phenotype in response to different environmental signals. In RA, MΦs are prone to polarize into the M1 phenotype. Reprogramming MΦs has shown promise in treating diseases, e.g., the chimeric antigen receptor-MΦ (CAR-M)-based adoptive immunotherapy. Interleukin-10 (IL-10) is one of the pivotal factors for M2 polarization. Clustered regularly interspaced short palindromic repeats-based transcriptional activation (CRISPRa) harnesses the native machinery in cells to enable a quick and efficient increase of endogenous gene expression. Here, we combined a CRISPRa system with adoptive cell therapy to construct engineered lastingly interleukin-ten (IL-10) expressed MΦs (Elite MΦs). The Elite MΦs possessed powerful anti-inflammatory capability and represented a pre-activated state of M2 MΦs in vitro. The Elite MΦs were more susceptible to an M2 inducer while resistant to M1 inducers. The Elite MΦs displayed enhanced chemotactic characteristics, leading to accumulated in vivo distribution at inflamed sites. Systemic administration of the Elite MΦs relieved inflammation, synovial hyperplasia and joint destruction in mouse models of RA. The Elite MΦs constructed by CRISPRa hold promise for addressing the current unmet medical need in RA.