Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Hum Gene Ther. 2022 Feb;33(3-4):119-130. doi: 10.1089/hum.2021.083. Epub 2022 Jan 6.
Glucocorticoids have anti-inflammatory and immunosuppressive functions and have commonly been used for preventing liver toxicity after the systemic application of a high dose of adeno-associated virus (AAV) vector for gene therapy. Clinical studies have reported that glucocorticoids have rescued factor IX (FIX) expression in patients with hemophilia B who showed a reduced FIX expression at 6 to 10 weeks post-AAV vector administration. In this study, we explored whether glucocorticoids could affect transgene expression in AAV targeted livers in animal models. When dexamethasone was applied before AAV9/FIX vector administration in the wild-type C57BL/6 mice, FIX expression was much higher than that of the control mice at any time point. More importantly, FIX expression transiently increased after dexamethasone was administered at week 6 or later post-AAV injection regardless of the various dexamethasone treatments applied. The transient enhancement in transgene expression was observed once there were one to several consecutive dexamethasone treatments completed. A similar result was also achieved in other wild-type BALB/c and hemophilia B mice that were treated with AAV9/FIX and dexamethasone. This mechanism study demonstrated that the administration of dexamethasone did not change either AAV genome copy number or transgene expression at the transcription level but transiently decreased interferon beta (IFN-β) and tumor necrosis factor alpha (TNF-α) expression in the livers of mice at a later time after AAV injection. Next, we studied the effect of dexamethasone on late transgene expression in hemophilia B dogs. Dexamethasone was administered 1 year after AAV9/FIX injection. Inconsistent with the results in mice, no significant change of FIX expression was observed in hemophilia B dogs. In summary, the results from this study indicate that dexamethasone may have various effects on transgene expression in AAV-transduced livers in different species, which provides valuable information about the rational application of dexamethasone in future clinical studies.
糖皮质激素具有抗炎和免疫抑制作用，常用于预防全身性给予高剂量腺相关病毒（AAV）载体进行基因治疗后的肝毒性。临床研究报道，糖皮质激素可挽救接受 AAV 载体治疗后 6 至 10 周时因子 IX（FIX）表达降低的乙型血友病患者的 FIX 表达。在这项研究中，我们探讨了糖皮质激素是否会影响动物模型中 AAV 靶向肝脏中的转基因表达。当在野生型 C57BL/6 小鼠中给予地塞米松前药，在任何时间点，FIX 表达均显著高于对照组。更重要的是，无论应用何种地塞米松处理方式，在 AAV 注射后第 6 周或更晚时给予地塞米松，FIX 表达均短暂增加。完成一次或多次连续地塞米松治疗后，即可观察到转基因表达的短暂增强。接受 AAV9/FIX 和地塞米松治疗的其他野生型 BALB/c 和乙型血友病小鼠也取得了类似的结果。该机制研究表明，地塞米松给药不会改变 AAV 基因组拷贝数或转录水平上的转基因表达，但可在 AAV 注射后较晚时间短暂降低小鼠肝脏中干扰素β（IFN-β）和肿瘤坏死因子α（TNF-α）的表达。接下来，我们研究了地塞米松对乙型血友病犬晚期转基因表达的影响。在 AAV9/FIX 注射后 1 年给予地塞米松。与小鼠的结果不一致，乙型血友病犬的 FIX 表达未观察到显著变化。总之，本研究结果表明，地塞米松可能对不同物种的 AAV 转导肝脏中的转基因表达产生各种影响，为地塞米松在未来临床研究中的合理应用提供了有价值的信息。
