Macrophage Membrane-Biomimetic Multi-Layered Nanoparticles Targeting Synovial Angiogenesis for Osteoarthritis Therapy.

Osteoarthritis (OA) is an inflammatory and progressive joint disease characterized by angiogenesis-mediated sustained, chronic, and low-grade synovitis. Anti-angiogenesis is emerging as a strategy for attenuating OA progression, but is often compromised by poor targeted drug delivery and immune clearance. Recent studies have identified macrophages formed a "protective barrier" in the lining layer (LL) of synovium, which blocked the communication of joint cavity and sublining layer (SL) of synovium. Inspired by natural mimicry, macrophage membrane-camouflaged drug delivery is explored to avoid immune clearance. Based on the single cell RNA sequencing, the CD34 synovial cells are identified as "sentinel cells" for synovium angiogenesis. Consequently, CD34 antibody-modified macrophage membrane is constructed to target new angiogenesis. Hence, a biomimetic multi-layered nanoparticle (NP) is developed that incorporates axitinib-loaded poly(lactic-co-glycolic) acid (PLGA) with CD34 antibody modified macrophage membrane (Atb@NP@Raw@CD34) to specifically deliver axitinib (Atb) to the SL and sustain inhibiting angiogenesis without immune elimination. It is found that the Atb@NP@Raw@CD34 can pass through macrophage "barrier", specifically targeting CD34 cells, continuously releasing Atb and anti-angiogenesis in OA synovitis. Furthermore, in vivo data demonstrated that Atb@NP@Raw@CD34 can attenuate joint degeneration by inhibiting synovium angiogenesis-mediated synovitis. In conclusion, local injection of Atb@NP@Raw@CD34 presents a promising approach for clinically impeding OA progression.