Gene delivery to the inner ear by transplantation of ex vivo gene-manipulated cells

感音神经性听力损失（SNHL）是一种常见的残疾，但目前的治疗选择仅限于人工耳蜗和助听器。因此，正在进行研究，以提供生物治疗的替代方法，包括基因治疗。需要开发安全有效的耳蜗基因传递方法，以促进这些听力损失治疗方法的临床应用。在这项研究中，我们研究了用非病毒载体将治疗分子输送到耳蜗的细胞基因治疗的潜力。将NIH3T3细胞脂质转染脑源性神经营养因子（BDNF）基因后，移植至小鼠内耳。免疫组织化学和western blotting显示移植后耳蜗内移植细胞存活长达四周。移植手术没有引起明显的听力损失。一项BDNF特异性酶联免疫吸附试验显示，工程细胞移植后，内耳BDNF的产生显著增加。这些发现表明，使用非病毒载体的细胞基因递送可能适用于局部、持续地将治疗分子递送到耳蜗。我们研究了骨髓基质细胞（BMSC）作为将基因或其产物传递到内耳组织的载体的潜力。将增强绿色荧光蛋白标记的骨髓间充质干细胞注入小鼠正常耳蜗淋巴周间隙。移植后2周的组织学分析表明，移植细胞在耳蜗组织内沉淀，尤其是螺旋韧带，尽管大多数移植物位于淋巴管周围空间。这些发现表明骨髓间充质干细胞在螺旋韧带中传递基因的潜力。

Sensorineural hearing loss (SNHL) is a common disability, but treatment options are currently limited to cochlear implants and hearing aids. Studies are therefore being conducted to provide alternative means of biological therapy, including gene therapy. Safe and effective methods of gene delivery to the cochlea need to be developed to facilitate the clinical application of these therapeutic treatments for hearing loss. In this study, we examined the potential of cell-gene therapy with non-viral vectors for delivery of therapeutic molecules into the cochlea. NIH3T3 cells were transfected with the brain-derived neurotrophic factor (BDNF) gene using lipofection and then transplanted into the mouse inner ear. Immunohistochemistry and western blotting demonstrated the survival of grafted cells in the cochlea for up to four weeks after transplantation. No significant hearing loss was induced by the transplantation procedure. A BDNF-specific enzyme-linked immunosorbent assay revealed a significant increase in BDNF production in the inner ear following transplantation of engineered cells. These findings indicate that cell-gene delivery with non-viral vectors may be applicable for the local, sustained delivery of therapeutic molecules into the cochlea. We examined the potential of bone-marrow stromal cell (BMSC) as a vehicle to deliver genes or their products into inner ear tissues. BMSCs labelled with enhanced green fluorescent protein were injected into the periplymphatic space of normal cochleae in mice. Histological analysis 2 weeks after transplantation demonstrated that transplanted cells settled within the cochlear tissues, especially in the spiral ligament, although most transplants were located in the perilymphatic space. These findings indicate the potential of BMSCs for delivering genes in the spiral ligament.