Biomaterials as vectors for the delivery of CRISPR-Cas9

Aptamer/Peptide-Functionalized Genome-Editing System for Effective Immune Restoration through Reversal of PD-L1-Mediated Cancer Immunosuppression

Effective reversal of tumor immunosuppression is of critical importance in cancer therapy. A multifunctional delivery vector that can effectively deliver CRISPR-Cas9 plasmid for β-catenin knockout to reverse tumor immunosuppression is constructed. The multi-functionalized delivery vector is decorated with aptamer-conjugated hyaluronic acid and peptide-conjugated hyaluronic acid to combine the tumor cell/nuclear targeting function of AS1411 with the cell penetrating/nuclear translocation function of TAT-NLS. Due to the significantly enhanced plasmid enrichment in malignant cell nuclei, the genome editing system can induce effective β-catenin knockout and suppress Wnt/β-catenin pathway, resulting in notably downregulated proteins involved in tumor progression and immunosuppression. Programmed death-ligand 1 (PD-L1) downregulation in edited tumor cells not only releases the PD-1/PD-L1 brake to improve the cancer killing capability of CD8⁺ T cells, but also enhances antitumor immune responses of immune cells. This provides a facile strategy to reverse tumor immunosuppression and to restore immunosurveillance and activate anti-tumor immunity.

CRISPR/Cas9-mediated knockout of MLL5 enhances apoptotic effect of cisplatin in HeLa cells in vitro

Mixed lineage leukemia 5 (MLL5) transactivates the expression of E6 and E7 oncogenes in cervical cancer cells. In this study, we utilized CRISPR/Cas9 system with the aim to target HPV-E6 and MLL5 to enhance apoptosis efficiency in HPV-18 positive HeLa cells and to improve chemotherapeutic efficacy of Cisplatin as the most common anticancer drug, used for cervical cancer. sgRNAs against MLL5 and E6 were designed and cloned into PX458 plasmid vector. Real-time PCR was used to determine knockout expression of MLL5 and E6 following, transfection with cloned plasmids. Cell viability and apoptosis were evaluated, using Dimethyl-thiazolyl diphenyl tetrazolium bromide (MTT) assay and Annexin V flow cytometry. ‏Cellular p‎53 level was measured, using enzyme linked immune sorbent assay (ELISA).‏ Real-time PCR indicated the downregulation of E6 and MLL5 in the transfected cells. A significant increase in the accumulation of P53 was observed due to targeting MLL5 and E6 genes. MTT and apoptosis assays showed a significant decrease in cell viability and enhanced apoptosis rate of transfected cells. Combination therapy showed that targeting E6 and MLL5 enhanced apoptotic effect of Cisplatin in MLL5 knockout cells in a synergistic manner. ‏The results suggest that CRISPR/Cas9 targeting of E6 and MLL5 genes can increase‎ apoptotic effects of Cisplatin and can be considered as a potential combination therapy for the treatment of HPV-‎related cervical cancer.

Ex vivo cell-based CRISPR/Cas9 genome editing for therapeutic applications

The recently developed CRISPR/Cas9 technology has revolutionized the genome engineering field. Since 2016, increasing number of studies regarding CRISPR therapeutics have entered clinical trials, most of which are focusing on the ex vivo genome editing. In this review, we highlight the ex vivo cell-based CRISPR/Cas9 genome editing for therapeutic applications. In these studies, CRISPR/Cas9 tools were used to edit cells in vitro and the successfully edited cells were considered as therapeutics, which can be introduced into patients to treat diseases. Considering a large number of previous reviews have been focused on the CRISPR/Cas9 delivery methods and materials, this review provides a different perspective, by mainly introducing the targeted conditions and design strategies for ex vivo CRISPR/Cas9 therapeutics. Brief descriptions of the history, functionality, and applications of CRISPR/Cas9 systems will be introduced first, followed by the design strategies and most significant results from previous research that used ex vivo CRISPR/Cas9 genome editing for the treatment of conditions or diseases. The last part of this review includes general information about the status of CRISPR/Cas9 therapeutics in clinical trials. We also discuss some of the challenges as well as the opportunities in this research area.

Niosome-Based Approach for In Situ Gene Delivery to Retina and Brain Cortex as Immune-Privileged Tissues

Non-viral vectors have emerged as a promising alternative to viral gene delivery systems due to their safer profile. Among non-viral vectors, recently, niosomes have shown favorable properties for gene delivery, including low toxicity, high stability, and easy production. The three main components of niosome formulations include a cationic lipid that is responsible for the electrostatic interactions with the negatively charged genetic material, a non-ionic surfactant that enhances the long-term stability of the niosome, and a helper component that can be added to improve its physicochemical properties and biological performance. This review is aimed at providing recent information about niosome-based non-viral vectors for gene delivery purposes. Specially, we will discuss the composition, preparation methods, physicochemical properties, and biological evaluation of niosomes and corresponding nioplexes that result from the addition of the genetic material onto their cationic surface. Next, we will focus on the in situ application of such niosomes to deliver the genetic material into immune-privileged tissues such as the brain cortex and the retina. Finally, as future perspectives, non-invasive administration routes and different targeting strategies will be discussed.

Oxidation-Responsive Nanoassemblies for Light-Enhanced Gene Therapy

Microenvironment-responsive supramolecular assemblies have attracted great interest in the biomedical field due to their potential applications in controlled drug release. In this study, oxidation-responsive supramolecular polycationic assemblies named CPAs are prepared for nucleic acid delivery via the host-guest interaction of β-cyclodextrin based polycations and a ferrocene-functionalized zinc tetraaminophthalocyanine core. The reactive oxygen species (ROS) can accelerate the disassembly of CPA/pDNA complexes, which would facilitate the release of pDNA in the complexes and further benefit the subsequent transfection. Such improvement in transfection efficiency is proved in A549 cells with high H₂ O₂ concentration. Interestingly, the transfection efficiencies mediated by CPAs are also different in the presence or absence of light in various cell lines such as HEK 293 and 4T1. The single oxygen (¹ O₂ ), produced by photosensitizers in the core of CPAs under light, increases the ROS amount and accelerates the disassembly of CPAs/pDNA complexes. In vitro and in vivo studies further illustrate that suppressor tumor gene p53 delivered by CPAs exhibits great antitumor effects under illumination. This work provides a promising strategy for the design and fabrication of oxidation-responsive nanoassemblies with light-enhanced gene transfection performance.

Engineered materials for in vivo delivery of genome-editing machinery

Genome editing technologies, such as CRISPR/Cas9, are promising for treating otherwise incurable genetic diseases. Great progress has been made for ex vivo genome editing; however, major bottlenecks exist in the development of efficient, safe, and targetable in vivo delivery systems, which are needed for the treatment of many diseases. To achieve high efficacy and safety in therapeutic in vivo genome editing, editing activities must be controlled spatially and temporally in the body, which requires novel materials, delivery strategies, and control mechanisms. Thus, there is currently a tremendous opportunity for the biomaterials research community to develop in vivo delivery systems that overcome the problems of low editing efficiency, off-targeting effect, safety, and cell and tissue specificity. In this Review, we summarize delivery approaches and provide perspectives on the challenges and possible solutions, aiming to stimulate further development of engineered materials for in vivo delivery of genome-editing machinery.

Exploration of Plant-Microbe Interactions for Sustainable Agriculture in CRISPR Era

Plants and microbes are co-evolved and interact with each other in nature. Plant-associated microbes, often referred to as plant microbiota, are an integral part of plant life. Depending on the health effects on hosts, plant-microbe (PM) interactions are either beneficial or harmful. The role of microbiota in plant growth promotion (PGP) and protection against various stresses is well known. Recently, our knowledge of community composition of plant microbiome and significant driving factors have significantly improved. So, the use of plant microbiome is a reliable approach for a next green revolution and to meet the global food demand in sustainable and eco-friendly agriculture. An application of the multifaceted PM interactions needs the use of novel tools to know critical genetic and molecular aspects. Recently discovered clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-mediated genome editing (GE) tools are of great interest to explore PM interactions. A systematic understanding of the PM interactions will enable the application of GE tools to enhance the capacity of microbes or plants for agronomic trait improvement. This review focuses on applying GE techniques in plants or associated microbiota for discovering the fundamentals of the PM interactions, disease resistance, PGP activity, and future implications in agriculture.

RNA delivery biomaterials for the treatment of genetic and rare diseases

Genetic and rare diseases (GARDs) affect more than 350 million patients worldwide and remain a significant challenge in the clinic. Hence, continuous efforts have been made to bridge the significant gap between the supply and demand of effective treatments for GARDs. Recent decades have witnessed the impressive progress in the fight against GARDs, with an improved understanding of the genetic origins of rare diseases and the rapid development in gene therapy providing a new avenue for GARD therapy. RNA-based therapeutics, such as RNA interference (RNAi), messenger RNA (mRNA) and RNA-involved genome editing technologies, demonstrate great potential as a therapy tool for treating genetic associated rare diseases. In the meantime, a variety of RNA delivery vehicles were established for boosting the widespread applications of RNA therapeutics. Among all the RNA delivery platforms which enable the systemic applications of RNAs, non-viral RNA delivery biomaterials display superior properties and a few biomaterials have been successfully exploited for achieving the RNA-based gene therapies on GARDs. In this review article, we focus on recent advances in the development of novel biomaterials for delivery of RNA-based therapeutics and highlight their applications to treat GARDs.