Layer-by-Layer Particles Deliver Epigenetic Silencing siRNA to HIV-1 Latent Reservoir Cell Types

For over two decades, nanomaterials have been employed to facilitate intracellular delivery of small interfering RNA (siRNA), both in vitro and in vivo, to induce post-transcriptional gene silencing (PTGS) via RNA interference. Besides PTGS, siRNAs are also capable of transcriptional gene silencing (TGS) or epigenetic silencing, which targets the gene promoter in the nucleus and prevents transcription via repressive epigenetic modifications. However, silencing efficiency is hampered by poor intracellular and nuclear delivery. Here, polyarginine-terminated multilayered particles are reported as a versatile system for the delivery of TGS-inducing siRNA to potently suppress virus transcription in HIV-infected cells. siRNA is complexed with multilayered particles formed by layer-by-layer assembly of poly(styrenesulfonate) and poly(arginine) and incubated with HIV-infected cell types, including primary cells. Using deconvolution microscopy, uptake of fluorescently labeled siRNA is observed in the nuclei of HIV-1 infected cells. Viral RNA and protein are measured to confirm functional virus silencing from siRNA delivered using particles 16 days post-treatment. This work extends conventional particle-enabled PTGS siRNA delivery to the TGS pathway and paves the way for future studies on particle-delivered siRNA for efficient TGS of various diseases and infections, including HIV.

Automated summary

Nanomaterials have been used for over two decades to deliver siRNA and induce PTGS, but poor intracellular and nuclear delivery hampers silencing efficiency. This study reports on the use of polyarginine-terminated multilayered particles as a versatile system for the delivery of TGS-inducing siRNA to effectively suppress virus transcription in HIV-infected cells. The siRNA is complexed with multilayered particles and taken up by the nuclei of HIV-infected cells, leading to functional virus silencing. This work expands the application of particle-enabled siRNA delivery to the TGS pathway and opens up possibilities for efficient TGS of various diseases and infections, including HIV.