Protocol Preview: In Vivo Gene Therapy Using Peptide-Based Delivery Blog post by Jasmin Skinner Gene therapy has been in discussion since 1972, but its translation to clinical practice has been a slow and challenging process [1]. Aside from its steep cost at 1.6 million dollars per patient [2], current gene modification methods are ethically questionable, short-lived, and can result in harmful immune responses [3]. More serious complications can also arise due to off-target effects, such as germ line mutations or activation/alteration of the incorrect portion of the genome [3]. Although current in vivo gene therapies are ineffective and controversial, a novel peptide-based delivery method could drastically improve future studies.

Current problems with in vivo gene therapy

While many researchers boast the benefits of gene therapy for treating recessive genetic disorders (e.g., sickle cell anemia, cystic fibrosis), very few therapies have seen success in clinical trials, in part due to the choice of vector [3]. Since viruses (and viral vectors) have evolved over millions of years to deliver DNA and RNA into a foreign host, they are extremely effective at delivering genetic material to a target cell in the context of gene therapy [4]. However, viral vectors must first get past the immune system. Immunity to viral capsules is one of the biggest challenges in gene therapy to date, as commonly used vectors are derived from harmless viruses circulating in humans [4]. Additionally, an undesired immune response could occur and be fatal for immunocompromised individuals [4]. On the other end of the spectrum, non-viral vectors for in vivo gene therapy greatly reduce the risk of unwanted immune responses, but with the trade-off of lower delivery efficiency [5]. Although advances in specificity, efficiency, and gene expression duration have led to their increased use in clinical trials, non-viral vector properties can still be improved [5]. As a solution to this translational challenge, Allen et al. have proposed a peptide-based delivery method of Cre recombinase for in vivo gene therapy [6]. https://insidescientific.com/wp-content/uploads/2022/03/Optimizing-CD34-Cell-Genome-Editing-for-Efficiency-and-HSPC-Maintenance_F1.jpg Optimizing CD34+ Cell Genome Editing for Efficiency and HSPC Maintenance In this webinar, Marta Walasek, PhD, and Danielle Nguyen Truong, BSc, provide an overview of hematopoietic stem and progenitor cells (HSPCs) and CRISPR-Cas9 genome editing, and define optimal culture conditions for an efficient genome editing workflow. WATCH NOW

Benefits of a peptide-based delivery method for gene modification

The authors sought to compare the efficacy of this peptide-based delivery method to adeno-associated viruses (AAVs), the most common in vivo gene delivery technique used to date. While AAVs are non-pathogenic and predictable, they have a very limited packaging capacity, slow gene expression, low transduction efficiency, and the potential to incorporate themselves into the host genome. Direct protein delivery can alleviate some of these issues, as intracellular activities can be initiated without a delay in transcription or translation. However, the technology for facilitating this direct delivery must first be improv