Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA.
Gene Ther. 2010 Dec;17(12):1476-83. doi: 10.1038/gt.2010.110. Epub 2010 Aug 19.
The IκB kinase (IKKα, β and the regulatory subunit IKKγ) complex regulates nuclear factor of κB (NF-κB) transcriptional activity, which is upregulated in many chronic inflammatory diseases. NF-κB signaling promotes inflammation and limits muscle regeneration in Duchenne muscular dystrophy (DMD), resulting in fibrotic and fatty tissue replacement of muscle that exacerbates the wasting process in dystrophic muscles. Here, we examined whether dominant-negative forms of IKKα (IKKα-dn) and IKKβ (IKKβ-dn) delivered by adeno-associated viral (AAV) vectors to the gastrocnemius (GAS) and tibialis anterior (TA) muscles of 1, 2 and 11-month-old mdx mice, a murine DMD model, block NF-κB activation and increase muscle regeneration. At 1 month post-treatment, the levels of nuclear NF-κB in locally treated muscle were decreased by gene transfer with either AAV-CMV-IKKα-dn or AAV-CMV-IKKβ-dn, but not by IKK wild-type controls (IKKα and β) or phosphate-buffered saline (PBS). Although treatment with AAV-IKKα-dn or AAV-IKKβ-dn vectors had no significant effect on muscle regeneration in young mdx mice treated at 1 and 2 months of age and collected 1 month later, treatment of old (11 months) mdx with AAV-CMV-IKKα-dn or AAV-CMV-IKKβ-dn significantly increased levels of muscle regeneration. In addition, there was a significant decrease in myofiber necrosis in the AAV-IKKα-dn- and AAV-IKKβ-dn-treated mdx muscle in both young and old mice. These results demonstrate that inhibition of IKKα or IKKβ in dystrophic muscle reduces the adverse effects of NF-κB signaling, resulting in a therapeutic effect. Moreover, these results clearly demonstrate the therapeutic benefits of inhibiting NF-κB activation by AAV gene transfer in dystrophic muscle to promote regeneration, particularly in older mdx mice, and block necrosis.
IKK 激酶（IKKα、β 和调节亚基 IKKγ）复合物调节核因子 κB（NF-κB）转录活性，该活性在许多慢性炎症性疾病中上调。NF-κB 信号促进 Duchenne 肌营养不良症（DMD）中的炎症，并限制肌肉再生，导致肌肉纤维化和脂肪组织替代，从而加剧营养不良肌肉的消耗过程。在这里，我们检查了通过腺相关病毒（AAV）载体递送到 1、2 和 11 月龄 mdx 小鼠（DMD 模型的一种鼠类）腓肠肌（GAS）和胫骨前肌（TA）的显性负形式 IKKα（IKKα-dn）和 IKKβ（IKKβ-dn）是否阻断 NF-κB 激活并增加肌肉再生。在治疗后 1 个月，通过基因转移用 AAV-CMV-IKKα-dn 或 AAV-CMV-IKKβ-dn 降低局部处理肌肉中的核 NF-κB 水平，但用 IKK 野生型对照（IKKα 和β）或磷酸盐缓冲盐水（PBS）则不会。尽管在 1 和 2 月龄时用 AAV-IKKα-dn 或 AAV-IKKβ-dn 载体治疗年轻的 mdx 小鼠，1 个月后收集时对肌肉再生没有显著影响，但用 AAV-CMV-IKKα-dn 或 AAV-CMV-IKKβ-dn 治疗老年（11 月龄）mdx 小鼠可显著增加肌肉再生水平。此外，在年轻和老年 mdx 肌肉中，用 AAV-IKKα-dn 和 AAV-IKKβ-dn 处理的 mdx 肌肉中的肌纤维坏死明显减少。这些结果表明，在营养不良的肌肉中抑制 IKKα 或 IKKβ 可降低 NF-κB 信号的不利影响，从而产生治疗效果。此外，这些结果清楚地表明，通过 AAV 基因转移抑制 NF-κB 激活在促进再生方面对营养不良肌肉具有治疗益处，特别是在老年 mdx 小鼠中，并阻止坏死。
