Engineered exosomes for targeted microRNA delivery to reverse liver fibrosis

Despite the widespread use of nucleic acid drugs in liver fibrosis treatment, their therapeutic efficacy remains limited due to challenges in penetrating extracellular matrix (ECM) and effectively targeting activated hepatic stellate cells (aHSCs). Exosomes (Exos) have emerged as promising drug carriers; however, their clinical application is hindered by low yield, limited drug-loading capacity, and suboptimal delivery efficiency. To overcome these challenges, we developed a nanosecond pulsed microfluidic system (T-nsPMs) for the high-throughput production of engineered Exos. These Exos were co-modified with a 5HT1D antibody and CD47 protein (TCMExos) to construct a nanoscale drug delivery system for the targeted delivery of microRNA-29b (miR-29b). TCMExos effectively penetrated the ECM, evaded macrophage phagocytosis, and targeted aHSCs, enabling the precise release of miR-29b at the site of fibrosis. This led to the inhibition of hepatic stellate cells activation, as demonstrated by the significant downregulation of α-SMA, COL1A1, TIMP-1, and phosphorylated SMAD2 proteins. Moreover, TCMExos markedly reduced collagen fibers deposition, showing excellent antifibrotic efficacy. Mechanistic studies revealed that TCMExos exert their antifibrotic efficacy by suppressing the TGF-β/SMAD signaling pathway. In conclusion, this work presents a new strategy for liver fibrosis treatment, offering an efficient and targeted approach to overcome current therapeutic limitations.