Heterologous survey of 130 DNA transposons in human cells highlights their functional divergence and expands the genome engineering toolbox.

Experimental studies on DNA transposable elements (TEs) have been limited in scale, leading to a lack of understanding of the factors influencing transposition activity, evolutionary dynamics, and application potential as genome engineering tools. We predicted 130 active DNA TEs from 102 metazoan genomes and evaluated their activity in human cells. We identified 40 active (integration-competent) TEs, surpassing the cumulative number (20) of TEs found previously. With this unified comparative data, we found that the Tc1/mariner superfamily exhibits elevated activity, potentially explaining their pervasive horizontal transfers. Further functional characterization of TEs revealed additional divergence in features such as insertion bias. Remarkably, in CAR-T therapy for hematological and solid tumors, Mariner2_AG (MAG), the most active DNA TE identified, largely outperformed two widely used vectors, the lentiviral vector and the TE-based vector SB100X. Overall, this study highlights the varied transposition features and evolutionary dynamics of DNA TEs and increases the TE toolbox diversity.

Identification of restrictive molecules involved in oncolytic virotherapy using genome-wide CRISPR screening.

Oncolytic viruses (OVs) offer a novel approach to treat solid tumors; however, their efficacy is frequently suboptimal due to various limiting factors. To address this challenge, we engineered an OV containing targets for neuron-specific microRNA-124 and Granulocyte-macrophage colony-stimulating factor (GM-CSF), significantly enhancing its neuronal safety while minimally compromising its replication capacity. Moreover, we identified PARP1 as an HSV-1 replication restriction factor using genome-wide CRISPR screening. In models of glioblastoma (GBM) and triple-negative breast cancer (TNBC), we showed that the combination of OV and a PARP inhibitor (PARPi) exhibited superior efficacy compared to either monotherapy. Additionally, single-cell RNA sequencing (scRNA-seq) revealed that this combination therapy sensitized TNBC to immune checkpoint blockade, and the incorporation of an immune checkpoint inhibitor (ICI) further increased the survival rate of tumor-bearing mice. The combination of PARPi and ICI synergistically enhanced the ability of OV to establish durable tumor-specific immune responses. Our study effectively overcomes the inherent limitations of OV therapy, providing valuable insights for the clinical treatment of TNBC, GBM, and other malignancies.

Modified lentiviral globin gene therapy for pediatric ß0/ß0 transfusion-dependent ß-thalassemia: A single-center, single-arm pilot trial.

ß0/ß0 thalassemia is the most severe type of transfusion-dependent ß-thalassemia (TDT) and is still a challenge facing lentiviral gene therapy. Here, we report the interim analysis of a single-center, single-arm pilot trial (NCT05015920) evaluating the safety and efficacy of a ß-globin expression-optimized and insulator-engineered lentivirus-modified cell product (BD211) in ß0/ß0 TDT. Two female children were enrolled, infused with BD211, and followed up for an average of 25.5 months. Engraftment of genetically modified hematopoietic stem and progenitor cells was successful and sustained in both patients. No unexpected safety issues occurred during conditioning or after infusion. Both patients achieved transfusion independence for over 22 months. The treatment extended the lifespan of red blood cells by over 42 days. Single-cell DNA/RNA-sequencing analysis of the dynamic changes of gene-modified cells, transgene expression, and oncogene activation showed no notable adverse effects. Optimized lentiviral gene therapy may safely and effectively treat all ß-thalassemia.

Genomic analysis of human brain metastases treated with stereotactic radiosurgery reveals unique signature based on treatment failure.

Stereotactic radiosurgery (SRS) has been shown to be efficacious for the treatment of limited brain metastasis (BM); however, the effects of SRS on human brain metastases have yet to be studied. We performed genomic analysis on resected brain metastases from patients whose resected lesion was previously treated with SRS. Our analyses demonstrated for the first time that patients possess a distinct genomic signature based on type of treatment failure including local failure, leptomeningeal spread, and radio-necrosis. Examination of the center and peripheral edge of the tumors treated with SRS indicated differential DNA damage distribution and an enrichment for tumor suppressor mutations and DNA damage repair pathways along the peripheral edge. Furthermore, the two clinical modalities used to deliver SRS, LINAC and GK, demonstrated differential effects on the tumor landscape even between controlled primary sites. Our study provides, in human, biological evidence of differential effects of SRS across BM's.

Changes of Facial Lipidomics by Intense Pulsed Light Treatment Based on LC-MS.

BACKGROUND: Intense pulsed light (IPL) has been widely used to improve cutaneous photoaging in recent years. Several studies began to explore the changes of skin barrier function after treatment, but the changes of skin surface lipids (SSL), especially specific lipid content and types are still unclear. METHODS: A total of 25 female volunteers were included in our study, and each of them received three full-face treatments with one month apart. Before the first treatment and 1 month after the last treatment, we collected clinical photos and skin stratum corneum samples from individuals. A 5-level scale was used to evaluate the efficacy of IPL treatment, liquid chromatography-mass spectrometry (LC-MS), and Orthogonal Partial Least Squares Discrimination Analysis (OPLS-DA) were used to analyze the changes of SSL. RESULTS: Two patients got no improvement after treatment, 6 patients had poor improvement and mild improvement was achieved in 9 patients, 5 and 3 patients reported moderate and significant improvement. The overall "effective" rate was 68 % and the "significant effective" rate was 32 %. The results showed 18 lipid subclasses and 487 lipid molecules were identified. The change of total lipid volume was not statistically significant (P = 0.088>0.05), but lipid subclass analysis showed the amount of Triglyceride (TG), Phosphatidic Acid (PA), Phosphatidylglycerol (PG) and Lysophosphatidylglycerol (LPG) were significantly increased (P < 0.05). There were 55 kinds of lipid molecules with significant difference after treatment (P < 0.05), and 51 of them belong to TG. The analysis of chain saturation of TG showed that the quantity of TG with 0, 1 and 2 unsaturated bonds increased significantly (P < 0.05). CONCLUSIONS: IPL treatment does not have a significant effect on the overall amount of lipids while the amount of TG, PA, PG, LPG were significantly increased. These lipid changes may potentially improve the skin barrier function, but more high-quality and comprehensive studies are still needed. BULLET POINT: Lipidomics analysis based on LC-MS; Changes of skin surface lipid after IPL treatment; the relationships between skin surface lipid and skin barrier functions. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Exploring the mechanism of Xiaoqinglong decoction in the treatment of infantile asthma based on network pharmacology and molecular docking.

To explore the mechanism of Xiaoqinglong decoction (XQLD) in the treatment of infantile asthma (IA) based on network pharmacology and molecular docking. The active ingredients of fdrugs in XQLD were retrieved from Traditional Chinese Medicine Systems Pharmacology database and then the targets of drug ingredients were screened. The disease targets of IA were obtained from OMIM and Gencards databases, and the intersection targets of XQLD in the treatment of IA were obtained by Venny 2.1 mapping of ingredient targets and disease targets. Cytoscape software was used to construct active ingredient-intersection target network. The potential targets of XQLD in the treatment of IA were analyzed by protein-protein interaction network using STRING platform, and the Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were obtained by R Studio software. AutoDock was used to perform molecular docking for verification. In this study, 150 active ingredients of XQLD were obtained, including quercetin, kaempferol, ß-sitosterol, luteolin, stigmasterol, and so on. And 92 intersection targets of drugs and diseases were obtained, including interleukin 6 (IL6), cystatin 3, estrogen receptor 1, hypoxia inducible factor 1A, HSP90AA1, epidermal growth factor receptor and so on. There were 127 items of Gene Ontology enrichment analysis and 125 Kyoto Encyclopedia of Genes and Genomes enrichment results, showing that apoptosis, IL-17 signaling pathway, tumor necrosis factor signaling pathway, P13K-Akt signaling pathway and other pathways may play a key role in the treatment of IA by XQLD. The results of molecular docking showed that the key active ingredients including quercetin, kaempferol, ß-sitosterol, luteolin, stigmasterol, and the core targets including IL6, cystatin 3, estrogen receptor 1, hypoxia inducible factor 1A, HSP90AA1, and epidermal growth factor receptor had good binding activity. Through network pharmacology and molecular docking, the potential targets and modern biological mechanisms of XQLD in the treatment of IA were preliminarily revealed in the study, which will provide reference for subsequent animal experiments and clinical trials.

Nuclear receptor modulators inhibit osteosarcoma cell proliferation and tumour growth by regulating the mTOR signaling pathway.

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Chemoresistance leads to poor responses to conventional therapy in patients with osteosarcoma. The discovery of novel effective therapeutic targets and drugs is still the main focus of osteosarcoma research. Nuclear receptors (NRs) have shown substantial promise as novel therapeutic targets for various cancers. In the present study, we performed a drug screen using 29 chemicals that specifically target 17 NRs in several different human osteosarcoma and osteoblast cell lines. The retinoic acid receptor beta (RARb) antagonist LE135, peroxisome proliferator activated receptor gamma (PPARg) antagonist T0070907, liver X receptor (LXR) agonist T0901317 and Rev-Erba agonist SR9011 significantly inhibited the proliferation of malignant osteosarcoma cells (U2OS, HOS-MNNG and Saos-2 cells) but did not inhibit the growth of normal osteoblasts. The effects of these NR modulators on osteosarcoma cells occurred in a dose-dependent manner and were not observed in NR-knockout osteosarcoma cells. These NR modulators also significantly inhibited osteosarcoma growth in vivo and enhanced the antitumour effect of doxorubicin (DOX). Transcriptomic and immunoblotting results showed that these NR modulators may inhibit the growth of osteosarcoma cells by regulating the PI3K/AKT/mTOR and ERK/mTOR pathways. DDIT4, which blocks mTOR activation, was identified as one of the common downstream target genes of these NRs. DDIT4 knockout significantly attenuated the inhibitory effects of these NR modulators on osteosarcoma cell growth. Together, our results revealed that modulators of RARb, PPARg, LXRs and Rev-Erba inhibit osteosarcoma growth both in vitro and in vivo through the mTOR signaling pathway, suggesting that treatment with these NR modulators is a novel potential therapeutic strategy.

The Efficacy of Fractional Carbon Dioxide Laser in Surgical Scars Treatment: A system Review and Meta-analysis.

BACKGROUND: Surgical scars seriously affect a patient's quality of life, and they have a strong impact on individuals. Many studies have reported the results of using fractional carbon dioxide (CO2) laser to treat surgical scars and have generally found it to be effective. OBJECTIVES: We conducted a meta-analysis with the objective of evaluating and proving the efficacy of fractional CO2 laser therapy for surgical scars. METHODS: We performed a search of databases including PubMed, Web of Science, Embase and the Cochrane Library. The outcomes of the meta-analysis were overall scores on the Vancouver Scar Scale (VSS) and its four dimensions (pigmentation, vascularity, pliability and height). Statistical analysis was performed using RevMan 5.4 software. RESULTS: A total of ten studies were included in this meta-analysis, including six randomized controlled trials (RCTs) and four nonrandomized controlled trials (N-RCTs). In the meta-analysis of RCTs and N-RCTs, similar results were obtained, and fractional CO2 laser irradiation significantly decreased VSS scores (P < 0.00001). In addition, fractional CO2 laser irradiation also had a significant effect on scores on the pigmentation (P = 0.08), vascularity (P = 0.001), flexibility (P = 0.005) and height (P = 0.008) dimensions. Except for mild pain during treatment and temporary erythema after treatment, most patients had no obvious adverse reactions. CONCLUSION: Our study found that fractional CO2 laser exhibits excellent efficacy and safety in terms of surgical scar treatment. Thus, we hope it becomes more widely available to patients with surgical scars. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266 .

Intense pulsed light treatment for inflammatory skin diseases: a review.

Although intense pulsed light (IPL) has been commonly used in the field of medical cosmetics in recent years, the exact outcomes of IPL in the treatment of inflammatory skin diseases remain unclear. To assess the clinical evidence for the use of IPL in the treatment of various inflammatory skin diseases and propose evidence-based recommendations, we searched for relevant publications in the PubMed and Web of Science databases and provided updated information. The inflammatory skin diseases treated with IPL consisted of acne vulgaris, rosacea, psoriasis, hidradenitis suppurativa (HS), atopic dermatitis (AD), Riehl's melanosis, lupus erythematosus, cutaneous sarcoidosis, pilonidal cysts, and pigmented actinic lichen planus (PALP). The efficacy of IPL treatment for these inflammatory skin diseases was described and evaluated. Forty-two studies were included to provide this assessment. The evidence suggests that IPL can effectively and safely improve acne vulgaris and rosacea (recommendation grade B). For other described inflammatory skin diseases, IPL can be used as a tentative or supplementary treatment (recommendation grade C and D). The main complications include transitory erythema, edema, and pain, with the possibility of hyperpigmentation, blisters, and a burning sensation in some individuals.

Efficacy and safety of pulsed dye laser for the treatment of surgical scars: a systematic review and meta-analysis.

Various clinical trials have explored whether the pulsed dye laser (PDL) method is safe to treat scars, especially surgical scars. However, comprehensive evidence confirming the exact outcomes of PDL for treating surgical scars is lacking. The efficacy and safety of PDL in the treatment of surgical scars were determined through a review of several studies. The PubMed, Embase, Cochrane Library, and Web of Science databases were searched, and the main clinical outcomes were Vancouver Scar Scale (VSS) scores in terms of pigmentation, vascularity, pliability, and height. Review Manager 5.4 software was used for statistical analyses of the data; we chose a standardized mean difference (SMZ) to present the results with 95% confidence interval (CI). Overall, seven randomized controlled trials were used for this meta-analysis, all of these papers used 585 nm or 595 nm PDL with 7 mm or 10 mm spot size and a fluence of 3.5 to 10 J/cm2 for treating surgical scars; besides, the pulse duration ranged from 450 µs to 10 ms. We found that PDL significantly resulted in decreased VSS scores (P = 0.02) in four aspects: pigmentation (P = 0.0002), vascularity (P < 0.00001), pliability (P = 0.0002), and height (P = 0.0002). Moreover, scar improvement was similar when using 585 nm and 595 nm PDL in terms of pigmentation (P = 0.76), vascularity (P = 0.34), pliability (P = 0.64), and height (P = 0.57). Furthermore, our review indicated that PDL has no obvious adverse effects for most people, except transitory erythema and purpura. The meta-analysis showed that both 585 nm and 595 nm PDL therapy can effectively reduce the VSS score, suggesting that PDL can be a safe and effective method for the treatment of surgical scars.

Systematic detection of functional proteoform groups from bottom-up proteomic datasets.

To a large extent functional diversity in cells is achieved by the expansion of molecular complexity beyond that of the coding genome. Various processes create multiple distinct but related proteins per coding gene - so-called proteoforms - that expand the functional capacity of a cell. Evaluating proteoforms from classical bottom-up proteomics datasets, where peptides instead of intact proteoforms are measured, has remained difficult. Here we present COPF, a tool for COrrelation-based functional ProteoForm assessment in bottom-up proteomics data. It leverages the concept of peptide correlation analysis to systematically assign peptides to co-varying proteoform groups. We show applications of COPF to protein complex co-fractionation data as well as to more typical protein abundance vs. sample data matrices, demonstrating the systematic detection of assembly- and tissue-specific proteoform groups, respectively, in either dataset. We envision that the presented approach lays the foundation for a systematic assessment of proteoforms and their functional implications directly from bottom-up proteomic datasets.

Lentiviral delivery of co-packaged Cas9 mRNA and a Vegfa-targeting guide RNA prevents wet age-related macular degeneration in mice.

Therapeutic genome editing requires effective and targeted delivery methods. The delivery of Cas9 mRNA using adeno-associated viruses has led to potent in vivo therapeutic efficacy, but can cause sustained Cas9 expression, anti-Cas9 immune responses and off-target edits. Lentiviral vectors have been engineered to deliver nucleases that are expressed transiently, but in vivo evidence of their biomedical efficacy is lacking. Here, we show that the lentiviral codelivery of Streptococcus pyogenes Cas9 mRNA and expression cassettes that encode a guide RNA that targets vascular endothelial growth factor A (Vegfa) is efficacious in a mouse model of wet age-related macular degeneration induced by Vegfa. A single subretinal injection of engineered lentiviruses knocked out 44% of Vegfa in retinal pigment epithelium and reduced the area of choroidal neovascularization by 63% without inducing off-target edits or anti-Cas9 immune responses. Engineered lentiviruses for the transient expression of nucleases may form the basis of new treatments for retinal neovascular diseases.

STEEP mediates STING ER exit and activation of signaling.

STING is essential for control of infections and for tumor immunosurveillance, but it can also drive pathological inflammation. STING resides on the endoplasmic reticulum (ER) and traffics following stimulation to the ERGIC/Golgi, where signaling occurs. Although STING ER exit is the rate-limiting step in STING signaling, the mechanism that drives this process is not understood. Here we identify STEEP as a positive regulator of STING signaling. STEEP was associated with STING and promoted trafficking from the ER. This was mediated through stimulation of phosphatidylinositol-3-phosphate (PtdIns(3)P) production and ER membrane curvature formation, thus inducing COPII-mediated ER-to-Golgi trafficking of STING. Depletion of STEEP impaired STING-driven gene expression in response to virus infection in brain tissue and in cells from patients with STING-associated diseases. Interestingly, STING gain-of-function mutants from patients interacted strongly with STEEP, leading to increased ER PtdIns(3)P levels and membrane curvature. Thus, STEEP enables STING signaling by promoting ER exit.

An overview of development in gene therapeutics in China.

After setbacks related to serious adverse events 20 years ago, gene therapy is now coming back to the central stage worldwide. In the past few years, gene therapy has shown astonishing efficacy against genetic diseases and cancers. In history, China carried out the world's second gene therapy clinical trial in 1991 for hemophilia B and approved the world's first gene therapy product-Gendicine-in 2003. In recent years, numerous efforts have been made on gene editing. Here, we reviewed the past of gene therapy in China and highlighted recent advances. We also discussed the regulations and future perspectives of gene therapy in China.

Huperzine A inhibits heroin-seeking behaviors induced by cue or heroin priming in rats.

Cholinergic systems modulate dopaminergic function in brain pathways are thought to mediate heroin addiction. This study investigated whether huperzine A, an acetylcholinesterase inhibitor, has beneficial effects on heroin reward and heroin-seeking behavior. Rats were trained to self-administer heroin (50 µg/kg/infusion) under the fixed ratio 1 schedule for 14 days and then drug-seeking was extinguished for 10 days, after which reinstatement of drug-seeking was induced by conditioned cues or heroin priming. Acute treatment with huperzine A at dose from 0.05 to 0.2 mg/kg potently and dose-dependently suppressed the cue- and heroin-induced reinstatement of heroin-seeking behavior following extinction. Huperzine A at these doses failed to alter either heroin rewarding effect or spontaneous locomotion activity. The study demonstrated that acute treatment with huperzine A inhibited heroin-seeking behavior, suggesting that huperzine A may be used as an adjuvant treatment for heroin relapse and addiction.

DeepAntigen: a novel method for neoantigen prioritization via 3D genome and deep sparse learning.

MOTIVATION: The mutations of cancers can encode the seeds of their own destruction, in the form of T-cell recognizable immunogenic peptides, also known as neoantigens. It is computationally challenging, however, to accurately prioritize the potential neoantigen candidates according to their ability of activating the T-cell immunoresponse, especially when the somatic mutations are abundant. Although a few neoantigen prioritization methods have been proposed to address this issue, advanced machine learning model that is specifically designed to tackle this problem is still lacking. Moreover, none of the existing methods considers the original DNA loci of the neoantigens in the perspective of 3D genome which may provide key information for inferring neoantigens' immunogenicity. RESULTS: In this study, we discovered that DNA loci of the immunopositive and immunonegative MHC-I neoantigens have distinct spatial distribution patterns across the genome. We therefore used the 3D genome information along with an ensemble pMHC-I coding strategy, and developed a group feature selection-based deep sparse neural network model (DNN-GFS) that is optimized for neoantigen prioritization. DNN-GFS demonstrated increased neoantigen prioritization power comparing to existing sequence-based approaches. We also developed a webserver named deepAntigen (http://yishi.sjtu.edu.cn/deepAntigen) that implements the DNN-GFS as well as other machine learning methods. We believe that this work provides a new perspective toward more accurate neoantigen prediction which eventually contribute to personalized cancer immunotherapy. AVAILABILITY AND IMPLEMENTATION: Data and implementation are available on webserver: http://yishi.sjtu.edu.cn/deepAntigen. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Targeted, homology-driven gene insertion in stem cells by ZFN-loaded 'all-in-one' lentiviral vectors.

Biased integration remains a key challenge for gene therapy based on lentiviral vector technologies. Engineering of next-generation lentiviral vectors targeting safe genomic harbors for insertion is therefore of high relevance. In a previous paper (Cai et al., 2014a), we showed the use of integrase-defective lentiviral vectors (IDLVs) as carriers of complete gene repair kits consisting of zinc-finger nuclease (ZFN) proteins and repair sequences, allowing gene correction by homologous recombination (HR). Here, we follow this strategy to engineer ZFN-loaded IDLVs that insert transgenes by a homology-driven mechanism into safe loci. This insertion mechanism is driven by time-restricted exposure of treated cells to ZFNs. We show targeted gene integration in human stem cells, including CD34(+) hematopoietic progenitors and induced pluripotent stem cells (iPSCs). Notably, targeted insertions are identified in 89% of transduced iPSCs. Our findings demonstrate the applicability of nuclease-loaded 'all-in-one' IDLVs for site-directed gene insertion in stem cell-based gene therapies.

Lentiviral Delivery of Proteins for Genome Engineering.

Viruses have evolved to traverse cellular barriers and travel to the nucleus by mechanisms that involve active transport through the cytoplasm and viral quirks to resist cellular restriction factors and innate immune responses. Virus-derived vector systems exploit the capacity of viruses to ferry genetic information into cells, and now - more than three decades after the discovery of HIV - lentiviral vectors based on HIV-1 have become instrumental in biomedical research and gene therapies that require genomic insertion of transgenes. By now, the efficacy of lentiviral gene delivery to stem cells, cells of the immune system including T cells, hepatic cells, and many other therapeutically relevant cell types is well established. Along with nucleic acids, HIV-1 virions carry the enzymatic tools that are essential for early steps of infection. Such capacity to package enzymes, even proteins of nonviral origin, has unveiled new ways of exploiting cellular intrusion of HIV-1. Based on early findings demonstrating the packaging of heterologous proteins into virus particles as part of the Gag and GagPol polypeptides, we have established lentiviral protein transduction for delivery of DNA transposases and designer nucleases. This strategy for delivering genome-engineering proteins facilitates high enzymatic activity within a short time frame and may potentially improve the safety of genome editing. Exploiting the full potential of lentiviral vectors, incorporation of foreign protein can be combined with the delivery of DNA transposons or a donor sequence for homology-directed repair in so-called 'all-in-one' lentiviral vectors. Here, we briefly describe intracellular restrictions that may affect lentiviral gene and protein delivery and review the current status of lentiviral particles as carriers of tool kits for genome engineering.

DNA transposition by protein transduction of the piggyBac transposase from lentiviral Gag precursors.

DNA transposon-based vectors have emerged as gene vehicles with a wide biomedical and therapeutic potential. So far, genomic insertion of such vectors has relied on the co-delivery of genetic material encoding the gene-inserting transposase protein, raising concerns related to persistent expression, insertional mutagenesis and cytotoxicity. This report describes potent DNA transposition achieved by direct delivery of transposase protein. By adapting integrase-deficient lentiviral particles (LPs) as carriers of the hyperactive piggyBac transposase protein (hyPBase), we demonstrate rates of DNA transposition that are comparable with the efficiency of a conventional plasmid-based strategy. Embedded in the Gag polypeptide, hyPBase is robustly incorporated into LPs and liberated from the viral proteins by the viral protease during particle maturation. We demonstrate lentiviral co-delivery of the transposase protein and vector RNA carrying the transposon sequence, allowing robust DNA transposition in a variety of cell types. Importantly, this novel delivery method facilitates a balanced cellular uptake of hyPBase, as shown by confocal microscopy, and allows high-efficiency production of clones harboring a single transposon insertion. Our findings establish engineered LPs as a new tool for transposase delivery. We believe that protein transduction methods will increase applicability and safety of DNA transposon-based vector technologies.

Efficient sleeping beauty DNA transposition from DNA minicircles.

DNA transposon-based vectors have emerged as new potential delivery tools in therapeutic gene transfer. Such vectors are now showing promise in hematopoietic stem cells and primary human T cells, and clinical trials with transposon-engineered cells are on the way. However, the use of plasmid DNA as a carrier of the vector raises safety concerns due to the undesirable administration of bacterial sequences. To optimize vectors based on the Sleeping Beauty (SB) DNA transposon for clinical use, we examine here SB transposition from DNA minicircles (MCs) devoid of the bacterial plasmid backbone. Potent DNA transposition, directed by the hyperactive SB100X transposase, is demonstrated from MC donors, and the stable transfection rate is significantly enhanced by expressing the SB100X transposase from MCs. The stable transfection rate is inversely related to the size of circular donor, suggesting that a MC-based SB transposition system benefits primarily from an increased cellular uptake and/or enhanced expression which can be observed with DNA MCs. DNA transposon and transposase MCs are easily produced, are favorable in size, do not carry irrelevant DNA, and are robust substrates for DNA transposition. In accordance, DNA MCs should become a standard source of DNA transposons not only in therapeutic settings but also in the daily use of the SB system.Molecular Therapy - Nucleic Acids (2013) 2, e74; doi:10.1038/mtna.2013.1; published online 26 February 2013.