Improving Viral-based Gene Delivery to Mammalian Cells through Simple Co-Incubation with Transportan Peptide In Vitro.

Viral-based platforms, most notably lentivirus and adeno-associated virus (AAV), are widely used to deliver genetic materials into cells for various purposes. One of the challenges in their applications is poor cellular uptake efficiency, especially in difficult-to-transfect cell lines and primary cells. Current mainstream approaches to overcome this problem often require specialized instruments or cause unwanted damages to cell viability. As an alternative, we have developed technologies to improve cellular uptake of macromolecular payloads by simply mixing them with cell-penetrating peptides (co-administration). Our previous studies have shown that co-administration with Transportan (TP), a 27-amino-acid amphiphilic cell-penetrating peptide, could enhance the cellular uptake of nano-sized particles. Here, we set out to investigate whether TP has similar effect on viral-based gene delivery. Using GFP-expressing AAVs and lentivirus, we validated the ability of TP co-administration to increase their transfection in a number of cell lines with limited cytotoxicity. Then, we used one difficult-to-transfect cell lines and two primary cells: a macrophage cell line (Raw264.7), bone marrow-derived macrophages (BMDMs), and retinal pigment epithelium (RPE) cells. Similar effects were seen as well. Overall, we present here an easy approach to improve the efficiency of viral-based gene delivery and transfection, which may benefit various clinical applications.