Promoting mitocytosis via gene-engineered aligned fibers for fascia regeneration

The abnormal accumulation of damaged mitochondria severely impedes tissue repair, and conventional therapeutic approaches, such as drug treatments, are often ineffective to remove damaged mitochondria. In this study, we developed gene-engineered aligned electrospun fibers by integrating microfluidic chip technology with a micro-sol oriented electrospinning technique. This study is the first to demonstrate the repair of damaged fascia by promoting mitocytosis through upregulating tetraspanin-9 (TSPAN9). The key gene for mitochondrial exocytosis, TSPAN9, was initially encapsulated into liposomes using microfluidic chip technology. Subsequently, core-shell structured aligned electrospun fibers were fabricated via oriented micro-sol electrospinning, where TSPAN9-loaded liposomes were protected by hyaluronic acid (HA) in the core layer, while aligned polylactic acid (PLA) fibers formed the outer shell layer. In vitro studies revealed that the aligned fibers closely mimicked the oriented structure of fascia tissue and significantly enhanced cell migration by providing directional physical cues. By sustained release of gene-loaded liposomes into cells, mitochondrial homeostasis was effectively restored, mitochondrial respiration was recovered, reactive oxygen species levels were reduced, and mitochondrial membrane potential was maintained. In vivo studies confirmed that these gene-engineered fibers effectively suppressed inflammatory responses and promoted fascia regeneration by facilitating the removal of damaged mitochondria through mitocytosis. In conclusion, gene-engineered fibers developed in this study, which enhance mitocytosis, offer a novel and promising therapeutic strategy for fascia tissue repair.