The recombinant adeno-associated virus (rAAV) vector has been successfully employed in clinical trials for patients with blindness and bleeding diseases as well as neuromuscular disorders. To date, it remains a major challenge to achieve higher transduction efficiency with a lower dose of rAAV vector. Our previous studies have demonstrated that serum proteins are able to directly interact with AAV virions for transduction enhancement. Herein, we explored the effect of the FerA domains, which are derived from ferlin proteins and possess membrane-fusion activity, on AAV transduction. Our results show that FerA domains from dysferlin, myoferlin, and otoferlin proteins are able to directly interact with AAV vectors and enhance AAV transduction in vitro and in mice through either intravenous or intramuscular injections. The enhanced AAV transduction induced by human/mouse FerA domains is achieved in various cell lines and in mice regardless of AAV serotypes. Mechanism studies demonstrated that the FerA domains could effectively enhance the ability of AAV vectors to bind to target cells and cross the vascular barrier. Additionally, FerA domains slow down the blood clearance of AAV. Systemic administration of AAV8/hFIX-FerA complex induced approximate 4-fold more human coagulation factor IX expression and improved hemostasis in hemophilia B mice than that of AAV8/hFIX. Collectively, we show, for the first time, that multiple FerA domains could be tethered on the AAV capsid and enhance widespread tissue distribution in an AAV serotypes-independent manner. This approach therefore holds a promise for future clinical application.

中文翻译：

---

膜融合 FerA 结构域增强腺相关病毒载体转导。

重组腺相关病毒 (rAAV) 载体已成功用于失明和出血性疾病以及神经肌肉疾病患者的临床试验。迄今为止，用较低剂量的 rAAV 载体实现更高的转导效率仍然是一项重大挑战。我们之前的研究表明，血清蛋白能够直接与 AAV 病毒粒子相互作用以增强转导。在此，我们探讨了源自 ferlin 蛋白并具有膜融合活性的 FerA 结构域对 AAV 转导的影响。我们的研究结果表明，dysferlin、myoferlin 和 otoferlin 蛋白的 FerA 结构域能够直接与 AAV 载体相互作用，并通过静脉内或肌肉内注射增强体外和小鼠体内的 AAV 转导。无论 AAV 血清型如何，人/小鼠 FerA 结构域诱导的 AAV 转导增强都在各种细胞系和小鼠中实现。机制研究表明，FerA 结构域可以有效增强 AAV 载体与靶细胞结合并穿过血管屏障的能力。此外，FerA 结构域减缓了 AAV 的血液清除。与 AAV8/hFIX 相比，AAV8/hFIX-FerA 复合物的全身给药在血友病 B 小鼠中诱导了大约 4 倍的人凝血因子 IX 表达并改善了止血。总的来说，我们首次表明，多个 Fe​​rA 结构域可以束缚在 AAV 衣壳上，并以独立于 AAV 血清型的方式增强广泛的组织分布。因此，这种方法有望用于未来的临床应用。