Delivery of miR-34a-5p by Folic Acid-Modified β-Cyclodextrin-Grafted Polyethylenimine Copolymer Nanocarriers to Resist KSHV

Kaposi's sarcoma-associated herpesvirus (KSHV)infectioncan cause a range of malignancies. The use of microRNA (miRNA) tocombat viruses and inhibit tumor development has received increasingattention. However, it is difficult for free miRNA to enter into cellsdirectly and to degrade easily. Therefore, the miRNA therapy aloneoften fails to achieve the expected effect. The selection of an appropriatedelivery system for effective miRNA delivery and anti-KSHV is rarelyconsidered. In this study, a beta-cyclodextrin-grafted polyethylenimine(beta-CD-PEI) was prepared by the chemical synthesis method, andfolic acid was further coupled to a nanocarrier (beta-CD-PEI-FA).Gel electrophoresis retardation experiments showed that beta-CD-PEI-FAcould combine with miR-34a-5p to form a drug-carrying nanocomplex beta-CD-PEI-FA/miR-34a-5p, which effectively protected miR-34a-5pfrom serum and nuclease degradation. The particle size and potentialwere 203.13 +/- 0.41 nm and 27.02 +/- 0.72 mV, respectively,which were suitable for endocytosis. The cytotoxicity of the vectorto KSHV-positive cells BCBL-1 and SK-RG cells was detected by theCCK-8 assay, which proved that the vector had good biosafety in vitro.Further cell experiments showed that beta-CD-PEI-FA/miR-34a-5pnot only had the ability to transport miR-34a-5p but also acceleratedthe G2-phase process of BCBL-1 and SK-RG cells and inhibited the proliferationof KSHV-infected cells. Most importantly, it can significantly reducethe expression levels of KSHV genes ORF26, K8.1A, and LANA. Therefore,the nanocarriers may be a promising antiviral drug delivery systemwith potential applications in the anti-KSHV therapy.

Automated summary

In this study, a beta-cyclodextrin-grafted polyethylenimine (beta-CD-PEI) was prepared and further coupled with folic acid to form a nanocarrier (beta-CD-PEI-FA) for miR-34a-5p delivery. The nanocomplex beta-CD-PEI-FA/miR-34a-5p effectively protected miR-34a-5p from degradation and exhibited suitable size and potential for endocytosis. The nanocarrier not only inhibited the proliferation of KSHV-infected cells but also reduced the expression levels of KSHV genes, suggesting its potential as an antiviral drug delivery system for anti-KSHV therapy.