Modular Lentiviral Vectors for Highly Efficient Transgene Expression in Resting Immune Cells

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.

End-to-End Approach to Surfactant Selection, Risk Mitigation, and Control Strategies for Protein-Based Therapeutics

A survey performed by the AAPS Drug Product Handling community revealed a general, mostly consensus, approach to the strategy for the selection of surfactant type and level for biopharmaceutical products. Discussing and building on the survey results, this article describes the common approach for surfactant selection and control strategy for protein-based therapeutics and focuses on key studies, common issues, mitigations, and rationale. Where relevant, each section is prefaced by survey responses from the 22 anonymized respondents. The article format consists of an overview of surfactant stabilization, followed by a strategy for the selection of surfactant level, and then discussions regarding risk identification, mitigation, and control strategy. Since surfactants that are commonly used in biologic formulations are known to undergo various forms of degradation, an effective control strategy for the chosen surfactant focuses on understanding and controlling the design space of the surfactant material attributes to ensure that the desired material quality is used consistently in DS/DP manufacturing. The material attributes of a surfactant added in the final DP formulation can influence DP performance (e.g., protein stability). Mitigation strategies are described that encompass risks from host cell proteins (HCP), DS/DP manufacturing processes, long-term storage, as well as during in-use conditions.

New Advances in Using Virus-like Particles and Related Technologies for Eukaryotic Genome Editing Delivery

The designer nucleases, including Zinc Finger Nuclease (ZFN), Transcription Activator-Like Effector Nuclease (TALEN), and Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated (CRISPR/Cas), have been widely used for mechanistic studies, animal model generation, and gene therapy development. Clinical trials using designer nucleases to treat genetic diseases or cancers are showing promising results. Despite rapid progress, potential off-targets and host immune responses are challenges to be addressed for in vivo uses, especially in clinical applications. Short-term expression of the designer nucleases is necessary to reduce both risks. Currently, delivery methods enabling transient expression of designer nucleases are being pursued. Among these, virus-like particles as delivery vehicles for short-term designer nuclease expression have received much attention. This review will summarize recent developments in using virus-like particles (VLPs) for safe delivery of gene editing effectors to complement our last review on the same topic. First, we introduce some background information on how VLPs can be used for safe and efficient CRISPR/Cas9 delivery. Then, we summarize recently developed virus-like particles as genome editing vehicles. Finally, we discuss applications and future directions.

Spinoculation and retronectin highly enhance the gene transduction efficiency of Mucin-1-specific chimeric antigen receptor (CAR) in human primary T cells

Background

Producing an appropriate number of engineered cells is considered as one of the influential factors in the successful treatments with chimeric antigen receptor (CAR) T cells. To this aim, the transduction rate of the viral vectors can play a significant role. In addition, improving transduction rates can affect the success rate of this treatment due to hard-transduced T lymphocytes.

Results

In this study, activated T cells were transduced using different transduction methods such as spinoculation, retronectin, polybrene, spinoculation + retronectin, and spinoculation + polybrene after selecting the most efficient transfection method to produce recombinant viral particles containing MUC1 CAR. PEI and lipofectamine with the amount of 73.72 and 72.53%, respectively, showed the highest transfection rates with respect to calcium phosphate (14.13%) for producing lentiviral particles. However, the cytotoxicity of transfection methods was not significantly different. Based on the results, spinoculation + retronectin leads to the highest transduction rates of T cells (63.19 ± 4.45%) relative to spinoculation + polybrene (34.6 ± 4.44%), polybrene (10.23 ± 0.79%), retronectin (10.37 ± 1.85%), and spinoculation (21.11 ± 1.55%). Further, the polybrene (40.02%) and spinoculation + polybrene (48.83% ± 4.83) increased cytotoxicity significantly compared to other groups.

Conclusion

Improving transduction conditions such as using spinoculation with retronectin can ameliorate the production of CAR-T cells by increasing the rate of transduction, as well as the success rate of treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-021-00397-z.