Recent Advances in Improving Gene-Editing Specificity through CRISPR-Cas9 Nuclease Engineering

Reporter Alleles in hiPSCs: Visual Cues on Development and Disease

Reporter alleles are essential for advancing research with human induced pluripotent stem cells (hiPSCs), notably in developmental biology and disease modeling. This study investigates the state-of-the-art gene-editing techniques tailored for generating reporter alleles in hiPSCs, emphasizing their effectiveness in investigating cellular dynamics and disease mechanisms. Various methodologies, including the application of CRISPR/Cas9 technology, are discussed for accurately integrating reporter genes into the specific genomic loci. The synthesis of findings from the studies utilizing these reporter alleles reveals insights into developmental processes, genetic disorder modeling, and therapeutic screening, consolidating the existing knowledge. These hiPSC-derived models demonstrate remarkable versatility in replicating human diseases and evaluating drug efficacy, thereby accelerating translational research. Furthermore, this review addresses challenges and future directions in refining the reporter allele design and application to bolster their reliability and relevance in biomedical research. Overall, this investigation offers a comprehensive perspective on the methodologies, applications, and implications of reporter alleles in hiPSC-based studies, underscoring their essential role in advancing both fundamental scientific understanding and clinical practice.

Model-directed generation of artificial CRISPR-Cas13a guide RNA sequences improves nucleic acid detection

CRISPR guide RNA sequences deriving exactly from natural sequences may not perform optimally in every application. Here we implement and evaluate algorithms for designing maximally fit, artificial CRISPR-Cas13a guides with multiple mismatches to natural sequences that are tailored for diagnostic applications. These guides offer more sensitive detection of diverse pathogens and discrimination of pathogen variants compared with guides derived directly from natural sequences and illuminate design principles that broaden Cas13a targeting.

Exploring Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR-Associated Protein 9 (CRISPR-Cas9) as a Therapeutic Modality for Cancer: A Scoping Review

The global burden of cancer and the limitations of conventional therapies highlight the potential of clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR-Cas9) in reshaping cancer treatment paradigms. In this review, we have investigated the mechanism of CRISPR, an adaptive immune system in bacteria that enables highly precise gene editing at the molecular level. This versatile tool demonstrates its efficacy in human cancer therapy through gene knockout, metabolic disruption, base editing, screening, and immunotherapy enhancement without affecting normal bodily domains. Despite its superiority over other nucleases like zinc-finger nucleases and transcription activator-like effector nucleases, hurdles such as off-target effects, inefficient delivery of the system to target cells, the emergence of escapers, and the ethical debate surrounding genome editing are discussed. In this article, we have reviewed the promising approaches of CRISPR-Cas9 in cancer treatment while exploring the underlying mechanism, advantages, and associated challenges.

Mitochondrial Genome Editing: Exploring the Possible Relationship of the Atherosclerosis-Associated Mutation m.15059G>A With Defective Mitophagy

Objective

The aim of this study was to evaluate the effect of the m.15059G>A mitochondrial nonsense mutation on cellular functions related to atherosclerosis, such as lipidosis, pro-inflammatory response, and mitophagy. Heteroplasmic mutations have been proposed as a potential cause of mitochondrial dysfunction, potentially disrupting the innate immune response and contributing to the chronic inflammation associated with atherosclerosis.

Methods

The human monocytic cell line THP-1 and cytoplasmic hybrid cell line TC-HSMAM1 were used. An original approach based on the CRISPR/Cas9 system was developed and used to eliminate mitochondrial DNA (mtDNA) copies carrying the m.15059G>A mutation in the MT-CYB gene. The expression levels of genes encoding enzymes related to cholesterol metabolism were analyzed using quantitative polymerase chain reaction. Pro-inflammatory cytokine secretion was assessed using enzyme-linked immunosorbent assays. Mitophagy in cells was detected using confocal microscopy.

Results

In contrast to intact TC-HSMAM1 cybrids, Cas9-TC-HSMAM1 cells exhibited a decrease in fatty acid synthase (FASN) gene expression following incubation with atherogenic low-density lipoprotein. TC-HSMAM1 cybrids were found to have defective mitophagy and an inability to downregulate the production of pro-inflammatory cytokines (to establish immune tolerance) upon repeated lipopolysaccharide stimulation. Removal of mtDNA harboring the m.15059G>A mutation resulted in the re-establishment of immune tolerance and the activation of mitophagy in the cells under investigation.

Conclusion

The m.15059G>A mutation was found to be associated with defective mitophagy, immune tolerance, and impaired metabolism of intracellular lipids due to upregulation of FASN in monocytes and macrophages.

dCas9 Tells Tales: Probing Gene Function and Transcription Regulation in Cancer

Clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editing is evolving into an essential tool in the field of biological and medical research. Notably, the development of catalytically deactivated Cas9 (dCas9) enzyme has substantially broadened its traditional boundaries in gene editing or perturbation. The conjugation of dCas9 with various molecular effectors allows precise control over transcriptional processes, epigenetic modifications, visualization of chromosomal dynamics, and several other applications. This expanded repertoire of CRISPR-Cas9 applications has emerged as an invaluable molecular tool kit that empowers researchers to comprehensively interrogate and gain insights into health and diseases. This review delves into the advancements in Cas9 protein engineering, specifically on the generation of various dCas9 tools that have significantly enhanced the CRISPR-based technology capability and versatility. We subsequently discuss the multifaceted applications of dCas9, especially in interrogating the regulation and function of genes that involve in supporting cancer pathogenesis. In addition, we also delineate the designing and utilization of dCas9-based tools as well as highlighting its current constraints and transformative potentials in cancer research.

Engineering Cas9: next generation of genomic editors

The Cas9 endonuclease of the CRISPR/Cas type IIA system from Streptococcus pyogenes is the heart of genome editing technology that can be used to treat human genetic and viral diseases. Despite its large size and other drawbacks, S. pyogenes Cas9 remains the most widely used genome editor. A vast amount of research is aimed at improving Cas9 as a promising genetic therapy. Strategies include directed evolution of the Cas9 protein, rational design, and domain swapping. The first generation of Cas9 editors comes directly from the wild-type protein. The next generation is obtained by combining mutations from the first-generation variants, adding new mutations to them, or refining mutations. This review summarizes and discusses recent advances and ways in the creation of next-generation genomic editors derived from S. pyogenes Cas9. KEY POINTS: • The next-generation Cas9-based editors are more active than in the first one. • PAM-relaxed variants of Cas9 are improved by increased specificity and activity. • Less mutagenic and immunogenic variants of Cas9 are created.

Expanding the DNA editing toolbox: Novel lambda integrase variants targeting microalgal and human genome sequences

Recombinase enzymes are extremely efficient at integrating very large DNA fragments into target genomes. However, intrinsic sequence specificities curtail their use to DNA sequences with sufficient homology to endogenous target motifs. Extensive engineering is therefore required to broaden applicability and robustness. Here, we describe the directed evolution of novel lambda integrase variants capable of editing exogenous target sequences identified in the diatom Phaeodactylum tricornutum and the algae Nannochloropsis oceanica. These microorganisms hold great promise as conduits for green biomanufacturing and carbon sequestration. The evolved enzyme variants show >1000-fold switch in specificity towards the non-natural target sites when assayed in vitro. A single-copy target motif in the human genome with homology to the Nannochloropsis oceanica site can also be efficiently targeted using an engineered integrase, both in vitro and in human cells. The developed integrase variants represent useful additions to the DNA editing toolbox, with particular application for targeted genomic insertion of large DNA cargos.

Recent Advancements in Reducing the Off-Target Effect of CRISPR-Cas9 Genome Editing

The CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)) and the associated protein (Cas9) system, a young but well-studied genome-editing tool, holds plausible solutions to a wide range of genetic disorders. The single-guide RNA (sgRNA) with a 20-base user-defined spacer sequence and the Cas9 endonuclease form the core of the CRISPR-Cas9 system. This sgRNA can direct the Cas9 nuclease to any genomic region that includes a protospacer adjacent motif (PAM) just downstream and matches the spacer sequence. The current challenge in the clinical applications of CRISPR-Cas9 genome-editing technology is the potential off-target effects that can cause DNA cleavage at the incorrect sites. Off-target genome editing confuses and diminishes the therapeutic potential of CRISPR-Cas9 in addition to potentially casting doubt on scientific findings regarding the activities of genes. In this review, we summarize the recent technological advancements in reducing the off-target effect of CRISPR-Cas9 genome editing.

Increasing Gene Editing Efficiency via CRISPR/Cas9- or Cas12a-Mediated Knock-In in Primary Human T Cells

T lymphocytes represent a promising target for genome editing. They are primarily modified to recognize and kill tumor cells or to withstand HIV infection. In most studies, T cell genome editing is performed using the CRISPR/Cas technology. Although this technology is easily programmable and widely accessible, its efficiency of T cell genome editing was initially low. Several crucial improvements were made in the components of the CRISPR/Cas technology and their delivery methods, as well as in the culturing conditions of T cells, before a reasonable editing level suitable for clinical applications was achieved. In this review, we summarize and describe the aforementioned parameters that affect human T cell editing efficiency using the CRISPR/Cas technology, with a special focus on gene knock-in.

Scaffold-based non-viral CRISPR delivery platform for efficient and prolonged gene activation to accelerate tissue regeneration

Clustered regularly interspaced short palindromic repeat activation (CRISPRa) technology has emerged as a precise genome editing tool for activating endogenous transgene expression. While it holds promise for precise cell modification, its translation into tissue engineering has been hampered by biosafety concerns and suboptimal delivery methods. To address these challenges, we have developed a CRISPRa non-viral gene delivery platform by immobilizing non-viral CRISPRa complexes into a biocompatible hydrogel/nanofiber (Gel/NF) composite scaffold. The Gel/NF scaffold facilitates the controlled and sustained release of CRISPRa complexes and also promotes cell recruitment to the scaffold for efficient and localized transfection. As a proof of concept, we employed this CRISPRa delivery platform to activate the vascular endothelial growth factor (VEGF) gene in a rat model with full-thickness skin defects. Our results demonstrate sustained upregulation of VEGF expression even at 21 days post-implantation, resulting in enhanced angiogenesis and improved skin regeneration. These findings underscore the potential of the Gel/NF scaffold-based CRISPRa delivery platform as an efficient and durable strategy for gene activation, offering promising prospects for tissue regeneration. STATEMENT OF SIGNIFICANCE: Translation of clustered regularly interspaced short palindromic repeat activation (CRISPRa) therapy to tissue engineering is limited by biosafety concerns and unsatisfactory delivery strategy. To solve this issue, we have developed a CRISPRa non-viral gene delivery platform by immobilizing non-viral CRISPRa complexes into a biocompatible hydrogel/nanofiber (Gel/NF) composite scaffold. This scaffold enables controlled and sustained release of CRISPRa and can induce cell recruitment for localized transfection. As a proof of concept, we activated vascular endothelial growth factor (VEGF) in a rat model with full-thickness skin defects, leading to sustained upregulation of VEGF expression, enhanced angiogenesis and improved skin regeneration in vivo. These findings demonstrate the potential of this platform for gene activation, thereby offering promising prospects for tissue regeneration.

Increasing the Activity of the High-Fidelity SpyCas9 Form in Yeast by Directed Mutagenesis of the PAM-Interacting Domain

CRISPR/Cas systems are used for genome editing, both in basic science and in biotechnology. However, CRISPR/Cas editors have several limitations, including insufficient specificity leading to "off-targets" and the dependence of activity on chromatin state. A number of highly specific Cas9 variants have now been obtained, but most of them are characterized by reduced activity on eukaryotic chromatin. We identified a spatial cluster of amino acid residues in the PAM-recognizing domain of Streptococcus pyogenes Cas9, whose mutations restore the activity of one of the highly specific forms of SpyCas9 without reducing its activity in Saccharomyces cerevisiae. In addition, one of these new mutations also increases the efficiency of SpyCas9-mediated editing of a site localized on the stable nucleosome. The improved Cas9 variants we obtained, which are capable of editing hard-to-reach regions of the yeast genome, may help in both basic research and yeast biotechnological applications.

Influence of N1-Methylpseudouridine in Guide RNAs on CRISPR/Cas9 Activity

At present, there are many strategies to improve the activity of CRISPR/Cas9. A well-known and effective approach is guide RNA modification. Many chemical guide RNA modifications have been studied, whereas naturally occurring RNA modifications are largely unexplored. N1-methylpseudouridine (m1Ψ) is an RNA base modification widely used in mRNA therapy, and it holds great promise for application in genome editing systems. The present study focuses on investigating the effect of N1-methylpseudouridine on the functioning of CRISPR/Cas9. In vitro cleavage assays helped determine the level of m1Ψ guide RNA modification that is sufficient to cleave the target substrate. By analyzing FAM-labeled dsDNA substrate cleavage, we calculated the kinetic parameters and the specificity scores of modified guide RNAs. Neon transfection and digital PCR enabled us to assess the activity of modified guide RNAs in mammalian cells. Our study shows that the presence of m1Ψ in guide RNAs can help preserve on-target genome editing while significantly reducing the off-target effects of CRISPR/Cas9 in vitro. We also demonstrate that Cas9 complexes with guide RNAs containing m1Ψ allow for genome editing in human cells. Thus, the incorporation of m1Ψ into guide RNAs supports CRISPR/Cas9 activity both in vitro and in cells.

Genome and transcriptome engineering by compact and versatile CRISPR-Cas systems

Comparative genomics has enabled the discovery of tiny clustered regularly interspaced short palindromic repeat (CRISPR) bacterial immune system effectors with enormous potential for manipulating eukaryotic genomes. Recently, smaller Cas proteins, including miniature Cas9, Cas12, and Cas13 proteins, have been identified and validated as efficient genome editing and base editing tools in human cells. The compact size of these novel CRISPR effectors is highly desirable for generating CRISPR-based therapeutic approaches, mainly to overcome in vivo delivery constraints, providing a promising opportunity for editing pathogenic mutations of clinical relevance and knocking down RNAs in human cells without inducing chromosomal insertions or genome alterations. Thus, these tiny CRISPR-Cas systems represent new and highly programmable, specific, and efficient platforms, which expand the CRISPR toolkit for potential therapeutic opportunities.

Recent Advances in CRISPR/Cas9 Delivery Approaches for Therapeutic Gene Editing of Stem Cells

Rapid advancement in genome editing technologies has provided new promises for treating neoplasia, cardiovascular, neurodegenerative, and monogenic disorders. Recently, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system has emerged as a powerful gene editing tool offering advantages, including high editing efficiency and low cost over the conventional approaches. Human pluripotent stem cells (hPSCs), with their great proliferation and differentiation potential into different cell types, have been exploited in stem cell-based therapy. The potential of hPSCs and the capabilities of CRISPR/Cas9 genome editing has been paradigm-shifting in medical genetics for over two decades. Since hPSCs are categorized as hard-to-transfect cells, there is a critical demand to develop an appropriate and effective approach for CRISPR/Cas9 delivery into these cells. This review focuses on various strategies for CRISPR/Cas9 delivery in stem cells.

CRISPR-based bioengineering in microalgae for production of industrially important biomolecules

Microalgae, as photosynthetic organisms, have the potential to produce biomolecules for use in food, feed, cosmetics, nutraceuticals, fuel, and other applications. Faster growth rates and higher protein and lipid content make microalgae a popular chassis for many industrial applications. However, challenges such as low productivity and high production costs have limited their commercialization. To overcome these challenges, bioengineering approaches such as genetic engineering, metabolic engineering, and synthetic biology have been employed to improve the productivity and quality of microalgae-based products. Genetic engineering employing genome editing tools like CRISPR/Cas allows precise and targeted genetic modifications. CRISPR/Cas systems are presently used to modify the genetic makeup of microalgae for enhanced production of specific biomolecules. However, these tools are yet to be explored explicitly in microalgae owing to some limitations. Despite the progress made in CRISPR-based bioengineering approaches, there is still a need for further research to optimize the production of microalgae-based products. This includes improving the efficiency of genome editing tools, understanding the regulatory mechanisms of microalgal metabolism, and optimizing growth conditions and cultivation strategies. Additionally, addressing the ethical, social, and environmental concerns associated with genetic modification of microalgae is crucial for the responsible development and commercialization of microalgae-based products. This review summarizes the advancements of CRISPR-based bioengineering for production of industrially important biomolecules and provides key considerations to use CRISPR/Cas systems in microalgae. The review will help researchers to understand the progress and to initiate genome editing experiments in microalgae.

Model-directed generation of CRISPR-Cas13a guide RNAs designs artificial sequences that improve nucleic acid detection

Generating maximally-fit biological sequences has the potential to transform CRISPR guide RNA design as it has other areas of biomedicine. Here, we introduce model-directed exploration algorithms (MEAs) for designing maximally-fit, artificial CRISPR-Cas13a guides-with multiple mismatches to any natural sequence-that are tailored for desired properties around nucleic acid diagnostics. We find that MEA-designed guides offer more sensitive detection of diverse pathogens and discrimination of pathogen variants compared to guides derived directly from natural sequences, and illuminate interpretable design principles that broaden Cas13a targeting.

CRISPR-Cas9 Activities with Truncated 16-Nucleotide RNA Guides Are Tuned by Target Duplex Stability Beyond the RNA/DNA Hybrid

CRISPR-Cas9 has been adapted as a readily programmable genome manipulation agent, and continuing technological advances rely on an in-depth mechanistic understanding of Cas9 target discrimination. Cas9 interrogates a target by unwinding the DNA duplex to form an R-loop, where the RNA guide hybridizes with one of the DNA strands. It has been shown that RNA guides shorter than the normal length of 20-nucleotide (-nt) support Cas9 cleavage activity by enabling partial unwinding beyond the RNA/DNA hybrid. To investigate whether DNA segment beyond the RNA/DNA hybrid can impact Cas9 target discrimination with truncated guides, Cas9 double-stranded DNA cleavage rates (kcat) were measured with 16-nt guides on targets with varying sequences at +17 to +20 positions distal to the protospacer-adjacent-motif (PAM). The data reveal a log-linear inverse correlation between kcat and the PAM+(17-20) DNA duplex dissociation free energy (ΔGNN(17-20)0), with sequences having smaller ΔGNN(17-20)0 showing faster cleavage and a higher degree of unwinding. The results indicate that, with a 16-nt guide, "peripheral" DNA sequences beyond the RNA/DNA hybrid contribute to target discrimination by tuning the cleavage reaction transition state through the modulation of PAM-distal unwinding. The finding provides mechanistic insights for the further development of strategies that use RNA guide truncation to enhance Cas9 specificity.

CRISPR/Cas9 Genome Editing for Tissue-Specific In Vivo Targeting: Nanomaterials and Translational Perspective

Clustered randomly interspaced short palindromic repeats (CRISPRs) and its associated endonuclease protein, i.e., Cas9, have been discovered as an immune system in bacteria and archaea; nevertheless, they are now being adopted as mainstream biotechnological/molecular scissors that can modulate ample genetic and nongenetic diseases via insertion/deletion, epigenome editing, messenger RNA editing, CRISPR interference, etc. Many Food and Drug Administration-approved and ongoing clinical trials on CRISPR adopt ex vivo strategies, wherein the gene editing is performed ex vivo, followed by reimplantation to the patients. However, the in vivo delivery of the CRISPR components is still under preclinical surveillance. This review has summarized the nonviral nanodelivery strategies for gene editing using CRISPR/Cas9 and its recent advancements, strategic points of view, challenges, and future aspects for tissue-specific in vivo delivery of CRISPR/Cas9 components using nanomaterials.

Decoding CRISPR-Cas PAM recognition with UniDesign

The critical first step in Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated (CRISPR-Cas) protein-mediated gene editing is recognizing a preferred protospacer adjacent motif (PAM) on target DNAs by the protein's PAM-interacting amino acids (PIAAs). Thus, accurate computational modeling of PAM recognition is useful in assisting CRISPR-Cas engineering to relax or tighten PAM requirements for subsequent applications. Here, we describe a universal computational protein design framework (UniDesign) for designing protein-nucleic acid interactions. As a proof of concept, we applied UniDesign to decode the PAM-PIAA interactions for eight Cas9 and two Cas12a proteins. We show that, given native PIAAs, the UniDesign-predicted PAMs are largely identical to the natural PAMs of all Cas proteins. In turn, given natural PAMs, the computationally redesigned PIAA residues largely recapitulated the native PIAAs (74% and 86% in terms of identity and similarity, respectively). These results demonstrate that UniDesign faithfully captures the mutual preference between natural PAMs and native PIAAs, suggesting it is a useful tool for engineering CRISPR-Cas and other nucleic acid-interacting proteins. UniDesign is open-sourced at https://github.com/tommyhuangthu/UniDesign.

Whole genome sequencing of CCR5 CRISPR-Cas9-edited Mauritian cynomolgus macaque blastomeres reveals large-scale deletions and off-target edits

Introduction: Genome editing by CRISPR-Cas9 approaches offers promise for introducing or correcting disease-associated mutations for research and clinical applications. Nonhuman primates are physiologically closer to humans than other laboratory animal models, providing ideal candidates for introducing human disease-associated mutations to develop models of human disease. The incidence of large chromosomal anomalies in CRISPR-Cas9-edited human embryos and cells warrants comprehensive genotypic investigation of editing outcomes in primate embryos. Our objective was to evaluate on- and off-target editing outcomes in CCR5 CRISPR-Cas9-targeted Mauritian cynomolgus macaque embryos. Methods: DNA isolated from individual blastomeres of two embryos, along with paternal and maternal DNA, was subjected to whole genome sequencing (WGS) analysis. Results: Large deletions were identified in macaque blastomeres at the on-target site that were not previously detected using PCR-based methods. De novo mutations were also identified at predicted CRISPR-Cas9 off-target sites. Discussion: This is the first report of WGS analysis of CRISPR-Cas9-targeted nonhuman primate embryonic cells, in which a high editing efficiency was coupled with the incidence of editing errors in cells from two embryos. These data demonstrate that comprehensive sequencing-based methods are warranted for evaluating editing outcomes in primate embryos, as well as any resultant offspring to ensure that the observed phenotype is due to the targeted edit and not due to unidentified off-target mutations.

Visualizing the Nucleome Using the CRISPR–Cas9 System: From in vitro to in vivo

One of the latest methods in modern molecular biology is labeling genomic loci in living cells using fluorescently labeled Cas protein. The NIH Foundation has made the mapping of the 4D nucleome (the three-dimensional nucleome on a timescale) a priority in the studies aimed to improve our understanding of chromatin organization. Fluorescent methods based on CRISPR-Cas are a significant step forward in visualization of genomic loci in living cells. This approach can be used for studying epigenetics, cell cycle, cellular response to external stimuli, rearrangements during malignant cell transformation, such as chromosomal translocations or damage, as well as for genome editing. In this review, we focused on the application of CRISPR-Cas fluorescence technologies as components of multimodal imaging methods for in vivo mapping of chromosomal loci, in particular, attribution of fluorescence signal to morphological and anatomical structures in a living organism. The review discusses the approaches to the highly sensitive, high-precision labeling of CRISPR-Cas components, delivery of genetically engineered constructs into cells and tissues, and promising methods for molecular imaging.

Delivery of CRISPR/Cas9 Plasmid DNA by Hyperbranched Polymeric Nanoparticles Enables Efficient Gene Editing

Gene editing nucleases such as CRISPR/Cas9 have enabled efficient and precise gene editing in vitro and hold promise of eventually achieving in vivo gene editing based therapy. However, a major challenge for their use is the lack of a safe and effective virus-free system to deliver gene editing nuclease elements. Polymers are a promising class of delivery vehicle due to their higher safety compared to currently used viral vectors, but polymers suffer from lower transfection efficiency. Polymeric vectors have been used for small nucleotide delivery but have yet to be used successfully with plasmid DNA (pDNA), which is often several hundred times larger than small nucleotides, presenting an engineering challenge. To address this, we extended our previously reported hyperbranched polymer (HP) delivery system for pDNA delivery by synthesizing several variants of HPs: HP-800, HP-1.8K, HP-10K, HP-25K. We demonstrate that all HPs have low toxicity in various cultured cells, with HP-25K being the most efficient at packaging and delivering pDNA. Importantly, HP-25K mediated delivery of CRISPR/Cas9 pDNA resulted in higher gene-editing rates than all other HPs and Lipofectamine at several clinically significant loci in different cell types. Consistently, HP-25K also led to more robust base editing when delivering the CRISPR base editor "BE4-max" pDNA to cells compared with Lipofectamine. The present work demonstrates that HP nanoparticles represent a promising class of vehicle for the non-viral delivery of pDNA towards the clinical application of gene-editing therapy.