Kutschenko Anna, Reinert Marie-Christine, Krez Nadja, Liebetanz David, Rummel Andreas
Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany.
Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany.
Neurotoxicology. 2017 Mar;59:1-8. doi: 10.1016/j.neuro.2016.12.008. Epub 2016 Dec 30.
The highly potent Botulinum neurotoxins (BoNT) are successful drugs to treat neuromuscular disorders. Efforts are being made to further reduce the injected BoNT dose and to lengthen the interval between treatments. Detailed knowledge of the BoNT structure-activity relationship (SAR) allows combining the best features of the different BoNT serotypes. Of all seven BoNT serotypes A-G, BoNT/A displays the highest potency despite low neuronal binding affinity, while BoNT/B exhibits much higher affinity. Recently, a new BoNT/AB hybrid (AABB) was constructed comprising the catalytic and translocation domain of BoNT/A and the 50kDa cell binding domain of BoNT/B. Here, we compared BoNT/A wild-type (AAAA) and AABB with regard to ex vivo potency and in vivo potency, efficacy and duration of action using the mouse phrenic nerve hemidiaphragm assay and the murine running wheel assay, respectively. The ex vivo potency of AABB was found to be 8.4-fold higher than that of AAAA. For the latter, two and 5 pg each of AAAA and AABB, respectively, were bilaterally injected into the calf muscles and mouse running wheel performance was automatically monitored during the following weeks to determine potency, efficacy and duration. Mice displayed a dose-dependent impairment of running performance. AABB showed potency, efficacy and duration equal to AAAA demonstrating successful exchange of the cell binding domain. AABB might combine the higher potency and longer duration of BoNT/A with the target specificity for the autonomic nervous system of BoNT/B. AABB might therefore constitute an improved treatment option for acetylcholine-mediated autonomic disorders such as hypersalivation or hyperhidrosis.
高效力的肉毒杆菌神经毒素（BoNT）是治疗神经肌肉疾病的成功药物。目前正在努力进一步降低BoNT的注射剂量，并延长治疗间隔时间。对BoNT结构-活性关系（SAR）的详细了解有助于结合不同BoNT血清型的最佳特性。在所有七种BoNT血清型A-G中，BoNT/A尽管神经元结合亲和力较低，但显示出最高的效力，而BoNT/B表现出更高的亲和力。最近，构建了一种新的BoNT/AB杂交体（AABB），它包含BoNT/A的催化和转位结构域以及BoNT/B的50kDa细胞结合结构域。在这里，我们分别使用小鼠膈神经半膈肌试验和小鼠跑步轮试验，比较了BoNT/A野生型（AAAA）和AABB在体外效力、体内效力、疗效和作用持续时间方面的差异。发现AABB的体外效力比AAAA高8.4倍。对于后者，分别将2 pg和5 pg的AAAA和AABB双侧注射到小腿肌肉中，并在接下来的几周内自动监测小鼠跑步轮的性能，以确定效力、疗效和持续时间。小鼠表现出剂量依赖性的跑步性能受损。AABB显示出与AAAA相等的效力、疗效和持续时间，表明细胞结合结构域的交换成功。AABB可能将BoNT/A的高效力和更长持续时间与BoNT/B对自主神经系统的靶标特异性结合起来。因此，AABB可能构成治疗乙酰胆碱介导的自主神经疾病（如流涎过多或多汗症）的一种改进选择。
