Microtubule inhibitors identified through nonbiased screening enhance DNA transfection efficiency by delaying p62‐dependent ubiquitin recruitment

• Published in: Genes to cells : devoted to molecular & cellular mechanisms Vol. 26; no. 9; pp. 739 - 751
• Main Authors: Tsuchiya, Megumi, Ogawa, Hidesato, Watanabe, Kento, Koujin, Takako, Mori, Chie, Nunomura, Kazuto, Lin, Bangzhong, Tani, Akiyoshi, Hiraoka, Yasushi, Haraguchi, Tokuko
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.09.2021
• Subjects: Animals; Autophagy; Cells, Cultured; Colchicine; Colchicine - pharmacology; Deoxyribonucleic acid; DNA; Efficiency; Endocytosis; Fibroblasts - drug effects; Fibroblasts - metabolism; gene delivery; Gene expression; High-Throughput Screening Assays - methods; high‐throughput screening; Mice; Microtubules - drug effects; Microtubules - metabolism; p62; Phagocytosis; phosphorylation; Polystyrene; Sequestosome-1 Protein - metabolism; Small Molecule Libraries - pharmacology; Transfection; Transfection - methods; transfection efficiency; Tubulin Modulators - pharmacology; Ubiquitin; Ubiquitin - metabolism; Ubiquitination; Vinblastine; Vinblastine - pharmacology; gene delivery; autophagy; ubiquitination; high-throughput screening; p62; phosphorylation; transfection efficiency
• ISSN: 1356-9597; 1365-2443
• DOI: 10.1111/gtc.12881

Ectopic gene expression is an indispensable tool in biology and medicine, but is often limited by the low efficiency of DNA transfection. We previously reported that depletion of the autophagy receptor p62/SQSTM1 enhances DNA transfection efficiency by preventing the degradation of transfected DNA. Therefore, p62 is a potential target for drugs to increase transfection efficiency. To identify such drugs, a nonbiased high‐throughput screening was applied to over 4,000 compounds from the Osaka University compound library, and their p62 dependency was evaluated. The top‐scoring drugs were mostly microtubule inhibitors, such as colchicine and vinblastine, and all of them showed positive effects only in the presence of p62. To understand the p62‐dependent mechanisms, the time required for p62‐dependent ubiquitination, which is required for autophagosome formation, was examined using polystyrene beads that were introduced into cells as materials that mimicked transfected DNA. Microtubule inhibitors caused a delay in ubiquitination. Furthermore, the level of phosphorylated p62 at S405 was markedly decreased in the drug‐treated cells. These results suggest that microtubule inhibitors inhibit p62‐dependent autophagosome formation. Our findings demonstrate for the first time that microtubule inhibitors suppress p62 activation as a mechanism for increasing DNA transfection efficiency and provide solutions to increase efficiency. Non‐biased high‐throughput screening for over 4,000 compounds revealed microtubule inhibitors such as colchicine and vinblastine enhance transfection efficiency. These microtubule inhibitors increase transfection efficiency by suppressing p62 phosphorylation that leads to the degradation of transfected DNA.