A DddA ortholog-based and transactivator-assisted nuclear and mitochondrial cytosine base editors with expanded target compatibility.

Bacterial double-stranded DNA (dsDNA) cytosine deaminase DddAtox-derived cytosine base editor (DdCBE) and its evolved variant, DddA11, guided by transcription-activator-like effector (TALE) proteins, enable mitochondrial DNA (mtDNA) editing at TC or HC (H = A, C, or T) sequence contexts, while it remains relatively unattainable for GC targets. Here, we identified a dsDNA deaminase originated from a Roseburia intestinalis interbacterial toxin (riDddAtox) and generated CRISPR-mediated nuclear DdCBEs (crDdCBEs) and mitochondrial CBEs (mitoCBEs) using split riDddAtox, which catalyzed C-to-T editing at both HC and GC targets in nuclear and mitochondrial genes. Moreover, transactivator (VP64, P65, or Rta) fusion to the tail of DddAtox- or riDddAtox-mediated crDdCBEs and mitoCBEs substantially improved nuclear and mtDNA editing efficiencies by up to 3.5- and 1.7-fold, respectively. We also used riDddAtox-based and Rta-assisted mitoCBE to efficiently stimulate disease-associated mtDNA mutations in cultured cells and in mouse embryos with conversion frequencies of up to 58% at non-TC targets.

A natural DNMT1 mutation elevates the fetal hemoglobin level via epigenetic derepression of the γ-globin gene in ß-thalassemia.

DNA methyltransferase 1 (DNMT1) is a major epigenetic regulator of the formation of large macromolecular complexes that repress human γ-globin expression by maintaining DNA methylation. However, very little is known about the association of DNMT1 variants with ß-thalassemia phenotypes. We systematically investigated associations between variants in DNMT1 and phenotypes in 1142 ß-thalassemia subjects and identified a novel missense mutation (c.2633G>A, S878F) in the DNMT1 bromo-adjacent homology-1 (BAH1) domain. We functionally characterized this mutation in CD34+ cells from patients and engineered HuDEP-2 mutant cells. Our results demonstrate that DNMT1 phosphorylation is abrogated by substituting serine with phenylalanine at position 878, resulting in lower stability and catalytic activity loss. S878F mutation also attenuated DNMT1 interactions with BCL11A, GATA1, and HDAC1/2, and reduced recruitment of DNMT1 to the γ-globin (HBG) promoters, leading to epigenetic derepression of γ-globin expression. By analyzing the F-cell pattern, we demonstrated that the effect of DNMT1 mutation on increased fetal hemoglobin (HbF) is heterocellular. Furthermore, introduction of S878F mutation into erythroid cells by clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) recapitulated γ-globin reactivation. Thus, the natural S878F DNMT1 mutation is a novel modulator of HbF synthesis and represents a potential new therapeutic target for ß-hemoglobinopathies.

Correction of the pathogenic mutation in TGM1 gene by adenine base editing in mutant embryos.

A couple diagnosed as carriers for lamellar ichthyosis, an autosomal recessive rare disease, encountered two pregnancy losses. Their blood samples showed the same heterozygous c.607C>T mutation in the TGM1 gene. However, we found that about 98.4% of the sperm had mutations, suggesting possible de novo germline mutation. To explore the probability of correcting this mutation, we used two different adenine base editors (ABEs) combined with related truncated single guide RNA (sgRNA) to repair the pathogenic mutation in mutant zygotes. Our results showed that the editing efficiency was 73.8% for ABEmax-NG combined with 20-bp-length sgRNA and 78.7% for Sc-ABEmax combined with 19-bp-length sgRNA. The whole-genome sequencing (WGS) and deep sequencing analysis demonstrated precise DNA editing. This study reveals the possibility of correcting the genetic mutation in embryos with the ABE system.

Helper-Polymer Based Five-Element Nanoparticles (FNPs) for Lung-Specific mRNA Delivery with Long-Term Stability after Lyophilization.

Lipid nanoparticles (LNPs) carrying therapeutic mRNAs hold great promise in treating lung-associated diseases like viral infections, tumors, and genetic disorders. However, because of their thermodynamically unstable nature, traditional LNPs carrying mRNAs need to be stored at low temperatures, which hinders their prevalence. Herein, an efficient lung-specific mRNA delivery platform named five-element nanoparticles (FNPs) is developed in which helper-polymer poly(ß-amino esters) (PBAEs) and DOTAP are used in combination. The new strategy endows FNPs with high stability by increasing the charge repulsion between nanoparticles and the binding force of the aliphatic chains within the nanoparticles. The structure-activity relationship (SAR) shows that PBAEs with E1 end-caps, higher degrees of polymerization, and longer alkyl side chains exhibit higher hit rates. Lyophilized FNP formulations can be stably stored at 4 °C for at least 6 months. Overall, a novel delivery platform with high efficiency, specificity, and stability was developed for advancing mRNA-based therapies for lung-associated diseases.

[Role of podocyte injury signaling pathway in steroid-resistant nephrotic syndrome and research progress in traditional Chinese medicine intervention].

As one of the main diseases leading to end-stage renal disease, steroid-resistant nephrotic syndrome(SRNS) can cause serious complications such as infection. Without effective control, this disease can further lead to the malignant development of the renal function, bringing serious social and economic burdens. As previously reported, the formation of SRNS is mostly related to the podocyte injury in the body, i.e., the injury of glomerular visceral epithelial cells. Phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt) signaling pathway, nuclear transcription factor-κB(NF-κB) signaling pathway, mammalian target of rapamycin(mTOR)/adenosine monophosphate(AMP)-activated protein kinase(AMPK), transforming growth factor(TGF)-ß1/Smads, and other signaling pathways are classical signaling pathways related to podocyte injury. By regulating the expression of signaling pathways, podocyte injury can be intervened to improve the adhesion between podocyte foot processes and glomerular basement membrane and promote the function of podocytes, thereby alleviating the clinical symptoms of SRNS. Through the literature review, traditional Chinese medicine(TCM) has unique advantages and an important role in intervening in podocyte injury. In the intervention in podocyte injury, TCM, by virtue of multi-target and multi-pathway role, can regulate and intervene in podocyte injury in many ways, alleviate the clinical symptoms of SRNS, and interfere with the progress of SRNS, reflecting the unique advantages of TCM. On the other hand, TCM can directly or indirectly inhibit podocyte injury by regulating the above signaling pathways, which can not only promote the effect of hormones and immunosuppressants and shorten the course of treatment, but also reduce the toxic and side effects caused by various hormones and immunosuppressants to exert the advantages of small side effects and low price of TCM. This article reviewed TCM in the treatment of SRNS by interfering with podocyte injury-related signaling pathways and is expected to provide a reference for the in-depth study of TCM in the treatment of SRNS, as well as a theoretical basis and a new direction for the clinical application of TCM to shorten the course of treatment of SRNS and delay the progression to end-stage renal disease.

Harnessing A3G for efficient and selective C-to-T conversion at C-rich sequences.

BACKGROUND: Site-specific C>T DNA base editing has been achieved by recruiting cytidine deaminases to the target C using catalytically impaired Cas proteins; the target C is typically located within 5-nt editing window specified by the guide RNAs. The prototypical cytidine base editor BE3, comprising rat APOBEC1 (rA1) fused to nCas9, can indiscriminately deaminate multiple C's within the editing window and also create substantial off-target edits on the transcriptome. A powerful countermeasure for the DNA off-target editing is to replace rA1 with APOBEC proteins which selectively edit C's in the context of specific motifs, as illustrated in eA3A-BE3 which targets TC. However, analogous editors selective for other motifs have not been described. In particular, it has been challenging to target a particular C in C-rich sequences. Here, we sought to confront this challenge and also to overcome the RNA off-target effects seen in BE3. RESULTS: By replacing rA1 with an optimized human A3G (oA3G), we developed oA3G-BE3, which selectively targets CC and CCC and is also free of global off-target effects on the transcriptome. Furthermore, we created oA3G-BE4max, an upgraded version of oA3G-BE3 with robust on-target editing. Finally, we showed that oA3G-BE4max has negligible Cas9-independent off-target effects at the genome. CONCLUSIONS: oA3G-BE4max can edit C(C)C with high efficiency and selectivity, which complements eA3A-editors to broaden the collective editing scope of motif selective editors, thus filling a void in the base editing tool box.

Correction of the Marfan Syndrome Pathogenic FBN1 Mutation by Base Editing in Human Cells and Heterozygous Embryos.

There are urgent demands for efficient treatment of heritable genetic diseases. The base editing technology has displayed its efficiency and precision in base substitution in human embryos, providing a potential early-stage treatment for genetic diseases. Taking advantage of this technology, we corrected a Marfan syndrome pathogenic mutation, FBN1T7498C. We first tested the feasibility in mutant cells, then successfully achieved genetic correction in heterozygous human embryos. The results showed that the BE3 mediated perfect correction at the efficiency of about 89%. Importantly, no off-target and indels were detected in any tested sites in samples by high-throughput deep sequencing combined with whole-genome sequencing analysis. Our study therefore suggests the efficiency and genetic safety of correcting a Marfan syndrome (MFS) pathogenic mutation in embryos by base editing.

[Cluster analysis of Dendrobium officinale from different populations through agronomy characterization].

Through resources investigation and sample collection,a total number of 392 Dendrobium officinale from 38 different populations,9 provinces were processed for measuring and observing.Fourteen agronomy characterizations like stem height,stem diameter,number of node in stem were selected for further classification.The cluster analysis was performed using Ward and Euclidean method.The results showed that the threshold of genetic distance was 2.77.Thirtyeight populations were divided into 6 groups.The factor analysis showed that,the leaf shape,stem shape,pitch length and leaf color were very important factors for classification.This study establish the foundation for analyzing the genetic relationship of D.officinale from different populations.

Isoviolanthin Extracted from Dendrobium officinale Reverses TGF-ß1-Mediated Epithelial⁻Mesenchymal Transition in Hepatocellular Carcinoma Cells via Deactivating the TGF-ß/Smad and PI3K/Akt/mTOR Signaling Pathways.

Dendrobium officinale is a precious medicinal herb and health food, and its pharmacological actions have been studied and proved. However, the mechanisms by which its active flavonoid glycosides affect epithelial⁻mesenchymal transition (EMT) in hepatocellular carcinoma (HCC) cells, such as HepG2 and Bel-7402 cells, have not been previously investigated. Therefore, we investigated whether isoviolanthin extracted from the leaves of Dendrobium officinale inhibits transforming growth factor (TGF)-ß1-induced EMT in HCC cells. In this study, the physicochemical properties and structure of isoviolanthin were identified by HPLC, UV, ESIMS, and NMR and were compared with literature data. HCC cells were pretreated with 10 ng/mL TGF-ß1 to induce EMT and then treated with isoviolanthin. Herein, we found that isoviolanthin exhibited no cytotoxic effects on normal liver LO2 cells but notably reduced the migratory and invasive capacities of TGF-ß1-treated HCC cells. Additionally, isoviolanthin treatment decreased matrix metalloproteinase (MMP)-2 and -9 levels, and remarkably altered the expression of EMT markers via regulating the TGF-ß/Smad and PI3K/Akt/mTOR signaling pathways; Western blot analysis confirmed that the effects of the inhibitors SB431542 and LY294002 were consistent with those of isoviolanthin. These findings demonstrate the potential of isoviolanthin as a therapeutic agent for the treatment of advanced-stage metastatic HCC.

Structural Characterization of Polysaccharides from Dendrobium officinale and Their Effects on Apoptosis of HeLa Cell Line.

Dendrobium officinale is a widely used medicinal plant in China with numerous bio-activities. However, the main structure and anti-tumor activity of the polysaccharides from this plant have not been investigated. In this study, we elucidated the main structure of polysaccharides purified with DEAE and Sephadex G-25 from Dendrobium officinale grown under different planting conditions. In addition, the anti-tumor activity was tested via MTT assays. The results showed that the polysaccharides of Dendrobium officinale grown under different conditions were almost the same, with slight differences in the branched chain; both polysaccharide fractions consisted of (1→4)-linked mannose and (1→4)-linked glucose, with an O-acetyl group in the mannose. After degradation, the polysaccharide fractions from wild plants showed significant anti-proliferation activity in HeLa cells. The fractions F1 and F3 induced apoptosis by up-regulating the expression of ERK, JNK, and p38. We concluded that polysaccharides from Dendrobium officinale planted in the wild exhibit significant anti-tumor effects only after being degraded to smaller molecular weight species. The planting mode is a significant factor in the pharmacological activity of Dendrobium officinale. We advise that the planting conditions for Dendrobium officinale should be changed.

[Dynamic change of four triterpenic acids contents in different organs of loquat (Eriobotrya japonica) and phenology].

The loquat is widely cultivated in China, its succulent fruits, leaves and flower are used as a traditional medicine for the treatment of many diseases. The study is aimed to analyse the content of the four triterpene compounds ( ursolic acid, corosolic acid, maslinic acid, oleanolic acid) in different organs, and investigate the dynamic changes in different phenological period. The triterpenic acids content in the samples was measured by HPLC based on the plant phenological observations. The results showed that order of four triterpenic acids content in different organs from high to low was defoliation (23.2 mg x g(-1)) > mature leaves (21.7 mg x g(-1)) > young leaves (17.5 mg x g(-1)) > fruits (7.36 mg x g(-1)) > flowers (6.40 mg x g(-1)). The triterpenic acids were not detected in the seeds. The total amount of the four triterpenic acids in the loquat leaves collected in the different phenological stages of sprout, flower bud, blossom and fruit varied between 17.8 and 26.2 mg x g(-1) (defoliation), 16.5 and 23.5 mg x g(-1) (mature leaves), 14.7 and 21.5 mg x g(-1) (young leaves), respectively. The content increased progressively with the leaf development, maturation and aging. There was a higher level of the dry material and triterpenic acids accumulation in the mature leaves during fruit enlargement. This paper attempts to present the case for medicinal plants of a broad geographical distribution to study on the secondary metabolites and harvesting time.

Global, regional, and national burden of syphilis, 1990-2021 and predictions by Bayesian age-period-cohort analysis: a systematic analysis for the global burden of disease study 2021.

Objective: To comprehensively assess the global burden of syphilis and related risk factors over 1990-2021, forecast future disease trends, and understand the impact of syphilis on global health. Methods: Global Burden of Disease Study 2021 (GBD 2021) data were used for age-, sex-, and region-stratified analysis of the numbers and age-standardized rates (per 100,000 population) of syphilis incidence, prevalence, deaths, and disability-adjusted life years (DALYs). Next, a differential analysis of syphilis risk factors was performed. Finally, trends for years after 2021 were predicted using Bayesian age-period-cohort (BAPC) prediction models. Results: In 2021, the total number of syphilis prevalence globally was 70,541,482.80 (95% uncertainty interval: 54,910,897.66-88,207,651.97), with the highest numbers noted in Central Sub-Saharan Africa [4,622.60 (95% uncertainty interval: 3,591.97-5,753.45)]. Over 1990-2021, the global age-standardized prevalence and incidence rates increased, whereas the age-standardized death and DALY rates decreased. Among all groups, infants aged <5 years demonstrated the highest age-standardized DALY rates. Moreover, the lower the sociodemographic index (SDI), the higher was the age-standardized rate. The primary factor contributing to syphilis disease burden was identified to be unsafe sex. BAPC analysis revealed an overall increase in age-standardized prevalence rate in the <5-year age group over 1990-2035, and the highest age-standardized prevalence rate occurred in the 25-34-year age group. Conclusion: Between 1990 and 2021, syphilis occurrence and prevalence increased consistently. Projections indicated a continual increase in syphilis incidence in children aged <5 years, and age-standardized prevalence rates were the highest in adults aged 25-34 years. Our results regarding the epidemiological trends of syphilis and its variations across regions, age groups, and sexes may aid policymakers in addressing the global impact of the disease effectively.

Phase evolution for oxidizing bismuth selenide.

The novel Bi2O2Se, produced by the oxidation of the layered Bi2Se3, has been considered as one of the most promising candidates for the next-generation electronics owing to its high carrier mobility and air-stability. In this work, by using crystal structure prediction and first-principles calculations, we report the phase transformations from the hexagonal Bi2Se3to the monoclinic Bi2OSe2, and then to the tetragonal Bi2O2Se with the gradual oxidization. Owing to the difference in electronegativity between selenium (Se) and oxygen (O), the oxidation process is accompanied by an increase in bond ionicity. Our results shed light on the phenomena occurring in the interaction between the precursors Bi2Se3and O2and have a potential contribution to the application of optoelectronic devices. The intermediate Bi2OSe2with calculated band gap of 1.01 eV, may be a candidate for photovoltaic application in future.

Functional Phosphoproteomics in Cancer Chemoresistance Using CRISPR-Mediated Base Editors.

Selective inhibition of targeted protein kinases is an effective therapeutic approach for treatment of human malignancies, which interferes phosphorylation of cellular substrates. However, a drug-imposed selection creates pressures for tumor cells to acquire chemoresistance-conferring mutations or activating alternative pathways, which can bypass the inhibitory effects of kinase inhibitors. Thus, identifying downstream phospho-substrates conferring drug resistance is of great importance for developing poly-pharmacological and targeted therapies. To identify functional phosphorylation sites involved in 5-fluorouracil (5-FU) resistance during its treatment of colorectal cancer cells, CRISPR-mediated cytosine base editor (CBE) and adenine base editor (ABE) are utilized for functional screens by mutating phosphorylated amino acids with two libraries specifically targeting 7779 and 10 149 phosphorylation sites. Among the top enriched gRNAs-induced gain-of-function mutants, the target genes are involved in cell cycle and post-translational covalent modifications. Moreover, several substrates of RSK2 and PAK4 kinases are discovered as main effectors in responding to 5-FU chemotherapy, and combinational treatment of colorectal cancer cells with 5-FU and RSK2 inhibitor or PAK4 inhibitor can largely inhibit cell growth and enhance cell apoptosis through a RSK2/TP53BP1/γ-H2AX phosphorylation signaling axis. It is proposed that this screen approach can be used for functional phosphoproteomics in chemotherapy of various human diseases.

Engineering of near-PAMless adenine base editor with enhanced editing activity and reduced off-target.

About 47% of pathogenic point mutations could be corrected by ABE-induced A·T-to-G·C conversions. However, the applications of ABEs are still hindered by undesired editing efficiency, limited editing scopes, and off-targeting effects. Here, we develop a new adenine base editor, by embedding TadA-8e monomer into SpRY-nCas9, named as CE-8e-SpRY, which exhibits higher activity at NRN than NYN PAMs favored by SpRY nuclease. CE-8e-SpRY could target nearly all genomic sites in principle and induces the highest targeting efficiency among tested SpRY-based ABEs. In addition, CE-8e-SpRY also shows reduced RNA and DNA off-targeting activities. With optimized sgRNAs, CE-8e-SpRY induces efficient or desired target editing at some disease-relevant loci where conventional ABEs were unable to induce precise and satisfied editing. Taken together, our CE-8e-SpRY could broaden the applicability of ABEs in correcting or introducing pathogenic point mutations.

PPARγ phase separates with RXRα at PPREs to regulate target gene expression.

Peroxisome proliferator-activated receptor (PPAR)-γ is a key transcription activator controlling adipogenesis and lipid metabolism. PPARγ binds PPAR response elements (PPREs) as the obligate heterodimer with retinoid X receptor (RXR) α, but exactly how PPARγ orchestrates the transcriptional response is unknown. This study demonstrates that PPARγ forms phase-separated droplets in vitro and solid-like nuclear condensates in cell, which is intriguingly mediated by its DNA binding domain characterized by the zinc finger motif. Furthermore, PPARγ forms nuclear condensates at PPREs sites through phase separation to compartmentalize its heterodimer partner RXRα to initiate PPARγ-specific transcriptional activation. Finally, using an optogenetic approach, the enforced formation of PPARγ/RXRα condensates leads to preferential enrichment at PPREs sites and significantly promotes the expression of PPARγ target genes. These results define a novel mechanism by which PPARγ engages the phase separation principles for efficient and specific transcriptional activation.

Structure-guided engineering of adenine base editor with minimized RNA off-targeting activity.

Both adenine base editors (ABEs) and cytosine base editors (CBEs) have been recently revealed to induce transcriptome-wide RNA off-target editing in a guide RNA-independent manner. Here we construct a reporter system containing E.coli Hokb gene with a tRNA-like motif for robust detection of RNA editing activities as the optimized ABE, ABEmax, induces highly efficient A-to-I (inosine) editing within an E.coli tRNA-like structure. Then, we design mutations to disrupt the potential interaction between TadA and tRNAs in structure-guided principles and find that Arginine 153 (R153) within TadA is essential for deaminating RNAs with core tRNA-like structures. Two ABEmax or mini ABEmax variants (TadA* fused with Cas9n) with deletion of R153 within TadA and/or TadA* (named as del153/del153* and mini del153) are successfully engineered, showing minimized RNA off-targeting, but comparable DNA on-targeting activities. Moreover, R153 deletion in recently reported ABE8e or ABE8s can also largely reduce their RNA off-targeting activities. Taken together, we develop a strategy to generate engineered ABEs (eABEs) with minimized RNA off-targeting activities.

San-Huang-Yi-Shen Capsule Ameliorates Diabetic Nephropathy in Rats Through Modulating the Gut Microbiota and Overall Metabolism.

San-Huang-Yi-Shen capsule (SHYS) has been used in the treatment of diabetic nephropathy (DN) in clinic. However, the mechanisms of SHYS on DN remain unknown. In this study, we used a high-fat diet (HFD) combined with streptozotocin (STZ) injection to establish a DN rat model. Next, we used 16S rRNA sequencing and untargeted metabolomics to study the potential mechanisms of SHYS on DN. Our results showed that SHYS treatment alleviated the body weight loss, hyperglycemia, proteinuria, pathological changes in kidney in DN rats. SHYS could also inhibite the oxidative stress and inflammatory response in kidney. 16S rRNA sequencing analysis showed that SHYS affected the beta diversity of gut microbiota community in DN model rats. SHYX could also decrease the Firmicutes to Bacteroidetes (F to B) ratio in phylum level. In genus level, SHYX treatment affected the relative abundances of Lactobacillus, Ruminococcaceae UCG-005, Allobaculum, Anaerovibrio, Bacteroides and Candidatus_Saccharimonas. Untargeted metabolomics analysis showed that SHYX treatment altered the serum metabolic profile in DN model rats through affecting the levels of guanidineacetic acid, L-kynurenine, prostaglandin F1α, threonine, creatine, acetylcholine and other 21 kind of metabolites. These metabolites are mainly involved in glycerophospholipid metabolism, tryptophan metabolism, alanine, aspartate and glutamate metabolism, arginine biosynthesis, tricarboxylic acid (TCA) cycle, tyrosine metabolism, arginine and proline metabolism, arginine and proline metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine metabolism, and D-glutamine and D-glutamate metabolism pathways. Spearman correlation analysis showed that Lactobacillus, Candidatus_Saccharimonas, Ruminococcaceae UCG-005, Anaerovibrio, Bacteroides, and Christensenellaceae_R-7_group were closely correlated with most of physiological data and the differential metabolites following SHYS treatment. In conclusion, our study revealed multiple ameliorative effects of SHYS on DN including the alleviation of hyperglycemia and the improvement of renal function, pathological changes in kidney, oxidative stress, and the inflammatory response. The mechanism of SHYS on DN may be related to the improvement of gut microbiota which regulates arginine biosynthesis, TCA cycle, tyrosine metabolism, and arginine and proline metabolism.

Modeling a cataract disorder in mice with prime editing.

Prime editing enables efficient introduction of targeted transversions, insertions, and deletions in mammalian cells and several organisms. However, genetic disease models with base deletions by prime editing have not yet been reported in mice. Here, we successfully generate a mouse model with a cataract disorder through microinjection of prime editor 3 (PE3) plasmids to efficiently induce targeted single-base deletion. Notably, a generated mouse with a high G-deletion rate (38.2%) displays a nuclear cataract phenotype; the PE3-induced deletions in mutant mice achieve high rates of germline transmission to their progenies, with phenotypic inheritance of cataract. Our data propose that modeling a genetic disease with a single nucleotide deletion in mice can be achieved with prime genome editing in vivo.

Increasing the targeting scope and efficiency of base editing with Proxy-BE strategy.

Base editors (BEs) are widely used in precise gene editing due to their simplicity and versatility. However, their efficiencies are hindered by various obstacles. Considering the chromatin microenvironment as a possible obstacle, here, we demonstrate a further development of the proxy-clustered regularly interspaced short palindromic repeats strategy, termed Proxy-BE, to increase gene editing efficiency. Specifically, a nuclease-dead Cas9 (dCas9) was bound to the sequence about 20-30 base pair away from the target site, potentially improving access to the DNA and, thus, providing a better editing microenvironment for base editors. Our findings confirm that nuclease-dead Streptococcus pyogenes Cas9 can assist the base editors SaKKH-BE3 and dCpf1-BE to double their canonical base editing efficiency. This work provides a new approach to enhance base editing, extending its scope for biological research and gene therapy.