Development and testing of AAV-delivered single-chain variable fragments for the treatment of methamphetamine abuse

Methamphetamine (METH) substance abuse disorders have major impact on society, yet no medications have proven successful at preventing METH relapse or cravings. Anti-METH monoclonal antibodies can reduce METH brain concentrations; however, this therapy has limitations, including the need for repeated dosing throughout the course of addiction recovery. An adeno-associated viral (AAV)-delivered DNA sequence for a single-chain variable fragment could offer long-term, continuous expression of anti-METH antibody fragments. For these studies, we injected mice via tail vein with 1 x 1012 vector genomes of two AAV8 scFv constructs and measured long-term expression of the antibody fragments. Mice expressed each scFv for at least 212 days, achieving micromolar scFv concentrations in serum. In separate experiments 21 days and 50 days after injecting mice with AAV-scFvs mice were challenged with METH in vivo. The circulating scFvs were capable of decreasing brain METH concentrations by up to 60% and sequestering METH in serum for 2 to 3 hrs. These results suggest that AAV-delivered scFv could be a promising therapy to treat methamphetamine abuse.

甲基苯丙胺（Methamphetamine, METH）物质使用障碍对社会造成严重危害，但目前尚无获批药物可有效预防METH复吸或渴求症状。抗METH单克隆抗体能够降低METH的脑内浓度，但该疗法存在局限性，例如在成瘾康复全程需反复给药。腺相关病毒（adeno-associated viral, AAV）递送的单链可变片段（single-chain variable fragment, scFv）DNA序列，可实现抗METH抗体片段的长期持续表达。本研究中，我们通过尾静脉向小鼠注射两种AAV8 scFv构建体的1×10^12个载体基因组，并检测了抗体片段的长期表达情况。结果显示，小鼠可稳定表达各scFv至少212天，血清中scFv浓度可达微摩尔级。在注射AAV-scFvs后的第21天和第50天开展独立实验，对小鼠进行体内METH攻毒实验。循环中的scFvs可将脑内METH浓度降低最高达60%，并在2至3小时内将METH截留于血清中。上述结果表明，AAV递送的scFv有望成为治疗甲基苯丙胺滥用的潜在疗法。