Duchenne muscular dystrophy is an X-linked monogenic disease caused by mutations in the dystrophin gene (DMD) characterized by progressive muscle weakness, leading to loss of ambulation and decreased life expectancy. Since the current standard of care for Duchenne muscular dystrophy is to merely treat symptoms, there is a dire need for treatment modalities that can correct the underlying genetic mutations. While several gene replacement therapies are being explored in clinical trials, one emerging approach that can directly correct mutations in genomic DNA is base editing. We have recently developed CRISPR-SKIP, a base editing strategy to induce permanent exon skipping by introducing C > T or A > G mutations at splice acceptors in genomic DNA, which can be used therapeutically to recover dystrophin expression when a genomic deletion leads to an out-of-frame DMD transcript. We now demonstrate that CRISPR-SKIP can be adapted to correct some forms of Duchenne muscular dystrophy by disrupting the splice acceptor in human DMD exon 45 with high efficiency, which enables open reading frame recovery and restoration of dystrophin expression. We also demonstrate that AAV-delivered split-intein base editors edit the splice acceptor of DMD exon 45 in cultured human cells and in vivo, highlighting the therapeutic potential of this strategy.

The COVID-19 pandemic has required a substantial increase in online course delivery across higher education. While hands-on laboratory courses are common offerings in biomedical engineering undergraduate programs that have been shown to improve learning outcomes [1], adapting them for online and remote formats is difficult. Specifically, practical skills (e.g., “The degree to which students can properly use scientific equipment, technology, and instrumentation, follow technical and professional protocols, and/or demonstrate proficiency in physical laboratory techniques, procedures, and measurements” [2]) are often regarded as challenging to teach outside a traditional laboratory setting [3]. In an effort to provide students enrolled in an online cell and tissue engineering lab course with hands-on activities for learning lab techniques, we prepared a kit containing the equipment and supplies needed to perform the activities remotely and mailed it to students. The activities included micropipetting exercises, casting and loading DNA gels, simulating cell culture, performing protein quantification and studying enzyme kinetics using protocols that were adapted to meet safety and equipment limitations. The instructors organized synchronous lab session meetings with students to review lab protocols and detailed videos of experiments as well as to discuss experimental design and data analysis. Finally, students also completed one asynchronous lab session and a livestreamed session facilitated by an instructor wearing a GoPro to compare to the synchronous pre-recorded video format. Students will be asked to complete an optional end of semester survey to assess the effectiveness of the online delivery format to accomplish the learning objectives. In this presentation we will provide a detailed description of the experiments we created and the delivery format we developed for online students as well as the student evaluation of instruction. The results of this work can be used to adopt similar at home instructional lab models at other institutions as well as guide the implementation of future online and hybrid lab course offerings.

The rapid spread of COVID-19 has fundamentally transformed our educational system. The need to protect both students and instructors from exposure to viral infection has required the implementation of remote instructional models.