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1.
J Ethnopharmacol ; 321: 117516, 2024 Mar 01.
Article En | MEDLINE | ID: mdl-38042390

ETHNOPHARMACOLOGICAL RELEVANCE: In the progression of chronic liver diseases, liver fibrosis is a reversible pathophysiologic event for liver diseases prognosis and risk of cirrhosis. Liver injury factors of different etiologies mediate this process. There is still a lack of effective medications for treating liver fibrosis. Additionally, the ameliorative effects of traditional herbs on liver fibrosis have been commonly reported. Tianhuang formula (THF) is a drug combination consisting of 2 traditional Chinese herbs, which has been showing significant improvement in metabolic liver diseases. However, the hepatoprotective effect and mechanism of THF in ameliorating liver fibrosis are still unclear. AIM OF THE STUDY: This study aimed to investigate the effects of THF on carbon tetrachloride (CCl4)-induced and methionine-choline-deficient (MCD) diet-induced liver fibrosis model and to reveal the potential mechanisms. It can provide experimental evidence for THF as a therapeutic candidate for liver fibrosis. MATERIALS AND METHODS: In this study, CCl4-induced mice were treated with THF (80 mg/kg, 160 mg/kg) or Fuzheng Huayu (FZHY) capsules (4.8 g/kg) for 6 weeks. MCD-induced mice received the same doses of THF or FZHY for 4 weeks. FZHY is used as a comparative study in these two models. Following that, using kit reagents detected changes in relevant serum and liver biochemical indicators. Histological changes in mouse liver were measured by staining of H&E and Sirius Red. The markers expression of liver fibrosis and inflammation were detected using qRT-PCR, western blotting and immunohistochemical staining analysis. The potential regulatory mechanism of THF to ameliorate liver fibrosis was performed by RNA-sequencing analysis. Finally, the analysis results were verified by immunofluorescence co-staining, qRT-PCR and western blotting. RESULTS: Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic triglyceride (TG) levels in CCl4 and MCD-induced liver fibrosis mice were significantly improved after THF treatment. Meanwhile, the expression of fibrosis and inflammation markers were significantly suppressed. Furthermore, THF downregulated the expression of the macrophage marker CD68. According to RNA-sequencing analysis, we found the CCL2-CCR2 axis and MAPK/NF-κB as the potential signaling pathway for THF against liver fibrosis. CONCLUSION: This study revealed that THF ameliorated liver injury, inflammation and fibrotic process by inhibiting CCL2-CCR2 axis and its downstream MAPK/NF-κB signaling pathway.


Liver Cirrhosis , NF-kappa B , Mice , Animals , NF-kappa B/metabolism , Liver Cirrhosis/chemically induced , Liver Cirrhosis/drug therapy , Liver Cirrhosis/metabolism , Liver , Fibrosis , Signal Transduction , Carbon Tetrachloride/pharmacology , Inflammation/pathology , RNA/metabolism , RNA/pharmacology , RNA/therapeutic use
2.
Molecules ; 28(13)2023 Jul 02.
Article En | MEDLINE | ID: mdl-37446826

Protein folding is a process in which a polypeptide must undergo folding process to obtain its three-dimensional structure. Thermodynamically, it is a process of enthalpy to overcome the loss of conformational entropy in folding. Folding is primarily related to hydrophobic interactions and intramolecular hydrogen bondings. During folding, hydrophobic interactions are regarded to be the driving forces, especially in the initial structural collapse of a protein. Additionally, folding is guided by the strong interactions within proteins, such as intramolecular hydrogen bondings related to the α-helices and ß-sheets of proteins. Therefore, a protein is divided into the folding key (FK) regions related to intramolecular hydrogen bondings and the non-folding key (non-FK) regions. Various conformations are expected for FK and non-FK regions. Different from non-FK regions, it is necessary for FK regions to form the specific conformations in folding, which are regarded as the necessary folding pathways (or "beacons"). Additionally, sequential folding is expected for the FK regions, and the intermediate state is found during folding. They are reflected on the local basins in the free energy landscape (FEL) of folding. To demonstrate the structural model, molecular dynamics (MD) simulations are conducted on the folding pathway of the TRP-cage in water.


Peptides , Water , Water/chemistry , Peptides/chemistry , Proteins/chemistry , Protein Folding , Thermodynamics , Hydrogen , Hydrogen Bonding , Protein Conformation
3.
Heliyon ; 9(5): e15691, 2023 May.
Article En | MEDLINE | ID: mdl-37205997

Anhui Province locates in the Yangtze River Delta region. The spatial difference between the north and the south is significant, and the air quality is improved over time. Studying the spatial and temporal changes of air pollution and its influencing factors for the coordinated control of air pollutants in the Yangtze River Delta region is significant. This study used the annual and monthly average data of six pollutants, PM2.5, PM10, O3, NO2, SO2, and CO, in Anhui Province and various cities from 2015 to 2021 and analyzed the spatiotemporal change characteristics using Excel and GIS software. Meanwhile, this paper used the SPSS correlation analysis method to analyze the correlation between pollutants and meteorological factors and analyzed the impact of economic development and environmental protection policies. The results are shown below. (1) The concentrations of SO2, NO2, and CO showed an overall downward trend at an interannual level. Meanwhile, the concentrations of PM10 and PM2.5 first increased slowly before 2017 and then declined, while the concentrations of O3 increased significantly before 2018 and then declined slowly. On a monthly scale, O3 presented an M-shaped change, while the other five pollutants basically presented a U-shaped change mode. The top monthly pollutants in each city followed the order of PM2.5, O3, PM10, and NO2. (2) PM2.5 and PM10 showed apparent characteristics of high concentrations in the north and low concentrations in the south in space. There were no significant differences in NO2, SO2, and CO pollution between the north and the south in space, and the differences in spatial pollution among cities were reduced significantly. (3) Five pollutants (SO2, NO2, PM10, PM2.5, and CO) except O3 were positively correlated, and the degree of correlation was correlated, strongly correlated, and above. However, five pollutants were negatively correlated with O3. The temperature had the most significant impact of negative correlation on five pollutants except for O3. The sunshine duration had the most significant impact on O3. (4) Economic growth and environmental protection policies in Anhui Province have positively affected environmental governance.

4.
Hepatol Commun ; 7(2): e0039, 2023 02 01.
Article En | MEDLINE | ID: mdl-36706173

Non-alcoholic steatohepatitis (NASH) has become a major cause of liver transplantation and liver-associated death. The gut-liver axis is a potential therapy for NASH. Sodium cholate (SC) is a choleretic drug whose main component is bile acids and has anti-inflammatory, antifibrotic, and hepatoprotective effects. This study aimed to investigate whether SC exerts anti-NASH effects by the gut-liver axis. Mice were fed with an high-fat and high-cholesterol (HFHC) diet for 20 weeks to induce NASH. Mice were daily intragastric administrated with SC since the 11th week after initiation of HFHC feeding. The toxic effects of SC on normal hepatocytes were determined by CCK8 assay. The lipid accumulation in hepatocytes was virtualized by Oil Red O staining. The mRNA levels of genes were determined by real-time quantitative PCR assay. SC alleviated hepatic injury, abnormal cholesterol synthesis, and hepatic steatosis and improved serum lipid profile in NASH mice. In addition, SC decreased HFHC-induced hepatic inflammatory cell infiltration and collagen deposition. The target protein-protein interaction network was established through Cytoscape software, and NR1H4 [farnesoid x receptor (FXR)] was identified as a potential target gene for SC treatment in NASH mice. SC-activated hepatic FXR and inhibited CYP7A1 expression to reduce the levels of bile acid. In addition, high-dose SC attenuated the abnormal expression of cancer markers in NASH mouse liver. Finally, SC significantly increased the expression of FXR and FGF15 in NASH mouse intestine. Taken together, SC ameliorates steatosis, inflammation, and fibrosis in NASH mice by activating hepatic and intestinal FXR signaling so as to suppress the levels of bile acid in NASH mouse liver and intestine.


Non-alcoholic Fatty Liver Disease , Mice , Animals , Non-alcoholic Fatty Liver Disease/etiology , Sodium Cholate , Receptors, Cytoplasmic and Nuclear/genetics , Bile Acids and Salts , Cholesterol , Lipids
5.
Curr Microbiol ; 80(1): 2, 2022 Nov 22.
Article En | MEDLINE | ID: mdl-36418790

The purpose of this study was to elucidate the roles of peptidoglycan-associated lipoprotein (Pal protein) in the proliferation of Brucella in macrophage and bacterial virulence, and to evaluate the immune effect of Pal protein to Salmonella enteritidis. Murine macrophage-like cell line Raw264.7 was stimulated by recombinant Pal protein, and the expression of TNF-α and IFN-γ were up-regulated, but not it of IL-1ß and IL-6. The macrophages infection and in vitro simulated stress assays showed that deletion of pal gene reduced the proliferation of Brucella in macrophages, the survival in acidic, oxidative and polymyxin B-contained environment. The mice infection assay showed that mice challenged with the pal mutant strain were found to have more severe splenomegaly, but less bacterial load. After oral immunization of mice, Pal protein induced a higher titer of mucosal and humoral antibody (IgA and IgG) against heat-killed Salmonella enteritidis, and a stronger Th1 cellular immune response. The challengte experiments showed Pal protein elevated the survival rate and reduced the bacterial load of spleens in immunized mice. In conclusion, our results revealed the important roles of pal gene in Brucella virulence, and Pal protein was a potentially valuable adjuvant against mucosal pathogens, such as Salmonella enteritidis.


Brucella , Mice , Animals , Salmonella enteritidis/genetics , Virulence , Macrophages , Cell Proliferation
6.
Front Endocrinol (Lausanne) ; 13: 864703, 2022.
Article En | MEDLINE | ID: mdl-35784533

Nonalcoholic steatohepatitis (NASH) has become a major cause of liver transplantation and liver-associated death. Targeting the gut-liver axis is a potential therapy for NASH. The Fufang Zhenzhu Tiaozhi (FTZ) capsule, a traditional Chinese medicine commonly used in clinical practice, has recently emerged as a promising drug candidate for metabolic diseases such as NASH. The present study aimed to investigate whether FTZ exerts an anti-NASH effect by targeting the gut-liver axis. Mice were fed with a high-fat diet (HFD) for 20 weeks to induce NASH. HFD-fed mice were daily intragastrically administrated with FTZ at 10 weeks after tbe initiation of HFD feeding. The mRNA levels of genes associated with the intestinal tight junction, lipid metabolism, and inflammation were determined by the q-PCR assay. Hepatic pathology was evaluated by H&E staining. The gut microbiota was analyzed by 16S rRNA gene sequencing. FTZ attenuated HFD-induced obesity, insulin resistance, and hepatic steatosis in mice. FTZ treatment decreased the elevated levels of serum aminotransferases and liver triglyceride in NASH mice. Furthermore, FTZ treatment reduced hepatic inflammatory cell infiltration and fibrosis in mice. In addition, FTZ attenuated the intestinal inflammatory response and improved intestinal barrier function. Mechanistically, FTZ-treated mice showed a different gut microbiota composition compared with that in HFD-fed mice. Finally, we identified eight differential metabolites that may contribute to the improvement of NASH with FTZ treatment. In summary, FTZ ameliorates NASH by inhibiting gut inflammation, improving intestinal barrier function, and modulating intestinal microbiota composition.


Non-alcoholic Fatty Liver Disease , Animals , Diet, High-Fat/adverse effects , Inflammation/pathology , Mice , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/drug therapy , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/metabolism , RNA, Ribosomal, 16S
7.
Sci Rep ; 12(1): 3419, 2022 03 01.
Article En | MEDLINE | ID: mdl-35233013

In heterogeneous wireless networks, random packet loss and high latency lead to conventional TCP variants performing unsatisfactorily in the case of competing communications. Especially on high-latency wireless links, conventional TCP variants are unable to estimate congestion degrees accurately for fine-grained congestion control because of the effects of random packet loss and delay oscillations. This paper proposes a TCP variant at the sender side to identify congestion degrees, namely TCP-WBQ, which quickly responses to the real congestion and effectively shields against random packet loss and oscillations of latency time. The proposed algorithm of congestion control firstly constructs a backlog-queue model based on the dynamics of the congestion window, and deduces the two bounds of the model which delimit oscillations of the backlog queue for non-congestion and random packet loss respectively. TCP-WBQ detects congestion degrees more accurately and thus implements the corresponding schemes of adjusting the congestion window, maintaining a tradeoff between high throughputs and congestion avoidance. The comprehensive simulations show that TCP-WBQ works efficiently in bandwidth utilization with single and multiple bottleneck scenarios, and achieves high performance and competitive fairness in heterogeneous wireless networks.


Computer Communication Networks , Software , Algorithms , Communication , Computer Simulation
8.
Mol Cell Endocrinol ; 520: 111064, 2021 01 15.
Article En | MEDLINE | ID: mdl-33091558

Recent evidence shows that long non-coding RNAs (lncRNAs), a class of non-coding RNAs, are involved in the regulation of reproductive processes. In this study, we identified a lncRNA, TCONS_00814106, that was upregulated in high-fecundity sow ovarian tissues and influenced by reproductive hormones. Bioinformatics analyses and luciferase reporter assays showed that TCONS_00814106 is a miR-1343 target. Cell counting kit (CCK)-8 and apoptosis assays showed that TCONS_00814106 promotes proliferation and inhibits apoptosis in porcine granulosa cells (GCs), and that this could be reversed by miR-1343. Also, we observed that transforming growth factor-ß receptor type I (TGFBR1) is a functional target of miR-1343 in GCs. TCONS_00814106 serves as a competing endogenous RNA to regulate TGFBR1 expression by sponging miR-1343, thereby exerting regulatory functions in GCs. Overall, these results provide new insights into the biological function of the lncRNA TCONS_00814106.


Granulosa Cells/cytology , Granulosa Cells/metabolism , MicroRNAs/metabolism , RNA, Long Noncoding/metabolism , Animals , Apoptosis/drug effects , Apoptosis/genetics , Base Sequence , Cell Proliferation/genetics , Chorionic Gonadotropin/pharmacology , Female , Follicle Stimulating Hormone/pharmacology , Gene Expression Regulation/drug effects , Granulosa Cells/drug effects , HEK293 Cells , Humans , MicroRNAs/genetics , RNA, Long Noncoding/genetics , Receptor, Transforming Growth Factor-beta Type I/metabolism , Swine
9.
Ann Hum Biol ; 47(1): 65-69, 2020 Feb.
Article En | MEDLINE | ID: mdl-31905040

Background: Currently, the Han population in China may be comprised of different genetic groups due to geographic, cultural and economic factors. Understanding population structure is very important for forensic purposes. However, knowledge of the genetic substructure within the whole Han population in China is still limited.Aim: This study is designed to ascertain the genetic structure of the Han population in China through genetic data from autosomal short tandem repeats (STRs).Subjects and methods: A set of 41 STR markers were analysed in 8725 unrelated Han Chinese males from the seven geographic regions of Northeast, North, East, Central, South, Southwest and Northwest in mainland China. Allele frequencies and F-statistics were estimated. Principal coordinate analysis (PCoA), phylogenetic analyses, analysis of molecular variance (AMOVA) and discriminant analysis of principal components (DAPC) were performed to explore the population structure.Results: Rare alleles that have not been observed in previous samples were detected. The small overall Fst values (0.0008), AMOVA and DAPC indicated that there is no population structure in Han Chinese. However, the PCoA and phylogenetic tree disclose a genetic differentiation pattern from north to south.Conclusions: There is no apparent population substructure in the Han population in China. However, genetic distances among the Han populations correlate with geographic locations.


Ethnicity/genetics , Gene Frequency , Microsatellite Repeats/genetics , China , Genetic Markers , Humans , Male , Phylogeny
10.
Cell Signal ; 62: 109337, 2019 10.
Article En | MEDLINE | ID: mdl-31173879

Radiation-induced tumor cells death is the theoretical basis of tumor radiotherapy. Death signaling disorder is the most important factor for radioresistance. However, the signaling pathway(s) leading to radiation-triggered cell death is (are) still not completely known. To better understand the cell death signaling induced by radiation, the immortalized mouse embryonic fibroblast (MEF) deficient in "initiator" caspases, "effector" caspases or different Bcl-2 family proteins together with human colon carcinoma cell HCT116 were used. Our data indicated that radiation selectively induced the activation of caspase-9 and caspase-3/7 but not caspase-8 by triggering mitochondrial outer membrane permeabilization (MOMP). Importantly, the role of radiation in MOMP is independent of the activation of both "initiator" and "effector" caspases. Furthermore, both proapoptotic and antiapoptotic Bcl-2 family proteins were involved in radiation-induced apoptotic signaling. Overall, our study indicated that radiation specifically triggered the intrinsic apoptotic signaling pathway through Bcl-2 family protein-dependent mitochondrial permeabilization, which indicates targeting mitochondria is a promising strategy for cancer radiotherapy.


Apoptosis/radiation effects , Mitochondria/radiation effects , Neoplasms/genetics , Proto-Oncogene Proteins c-bcl-2/genetics , Animals , Apoptosis/genetics , Caspase 3/genetics , Caspase 7/genetics , Caspase 9/genetics , Cell Death , Fibroblasts/radiation effects , HCT116 Cells , Humans , Mice , Mitochondria/genetics , Mitochondrial Transmembrane Permeability-Driven Necrosis/radiation effects , Neoplasms/pathology , Neoplasms/radiotherapy
11.
Nucleic Acids Res ; 46(16): 8275-8298, 2018 09 19.
Article En | MEDLINE | ID: mdl-29947794

CRISPR/Cas9 is an attractive platform to potentially correct dominant genetic diseases by gene editing with unprecedented precision. In the current proof-of-principle study, we explored the use of CRISPR/Cas9 for gene-editing in myotonic dystrophy type-1 (DM1), an autosomal-dominant muscle disorder, by excising the CTG-repeat expansion in the 3'-untranslated-region (UTR) of the human myotonic dystrophy protein kinase (DMPK) gene in DM1 patient-specific induced pluripotent stem cells (DM1-iPSC), DM1-iPSC-derived myogenic cells and DM1 patient-specific myoblasts. To eliminate the pathogenic gain-of-function mutant DMPK transcript, we designed a dual guide RNA based strategy that excises the CTG-repeat expansion with high efficiency, as confirmed by Southern blot and single molecule real-time (SMRT) sequencing. Correction efficiencies up to 90% could be attained in DM1-iPSC as confirmed at the clonal level, following ribonucleoprotein (RNP) transfection of CRISPR/Cas9 components without the need for selective enrichment. Expanded CTG repeat excision resulted in the disappearance of ribonuclear foci, a quintessential cellular phenotype of DM1, in the corrected DM1-iPSC, DM1-iPSC-derived myogenic cells and DM1 myoblasts. Consequently, the normal intracellular localization of the muscleblind-like splicing regulator 1 (MBNL1) was restored, resulting in the normalization of splicing pattern of SERCA1. This study validates the use of CRISPR/Cas9 for gene editing of repeat expansions.


CRISPR-Cas Systems , Gene Editing/methods , Induced Pluripotent Stem Cells/metabolism , Myoblasts/metabolism , Myotonic Dystrophy/genetics , Trinucleotide Repeat Expansion/genetics , Cells, Cultured , Child , Female , Humans , Middle Aged , Muscle Development/genetics , Myotonic Dystrophy/metabolism , Myotonic Dystrophy/pathology
12.
Nat Med ; 21(11): 1357-63, 2015 Nov.
Article En | MEDLINE | ID: mdl-26398868

The vast majority of disease-associated single-nucleotide polymorphisms (SNPs) mapped by genome-wide association studies (GWASs) are located in the non-protein-coding genome, but establishing the functional and mechanistic roles of these sequence variants has proven challenging. Here we describe a general pipeline in which candidate functional SNPs are first evaluated by fine mapping, epigenomic profiling, and epigenome editing, and then interrogated for causal function by using genome editing to create isogenic cell lines followed by phenotypic characterization. To validate this approach, we analyzed the 6q22.1 prostate cancer risk locus and identified rs339331 as the top-scoring SNP. Epigenome editing confirmed that the rs339331 region possessed regulatory potential. By using transcription activator-like effector nuclease (TALEN)-mediated genome editing, we created a panel of isogenic 22Rv1 prostate cancer cell lines representing all three genotypes (TT, TC, CC) at rs339331. Introduction of the 'T' risk allele increased transcription of the regulatory factor 6 (RFX6) gene, increased homeobox B13 (HOXB13) binding at the rs339331 region, and increased deposition of the enhancer-associated H3K4me2 histone mark at the rs339331 region compared to lines homozygous for the 'C' protective allele. The cell lines also differed in cellular morphology and adhesion, and pathway analysis of differentially expressed genes suggested an influence of androgens. In summary, we have developed and validated a widely accessible approach that can be used to establish functional causality for noncoding sequence variants identified by GWASs.


Chromosomes, Human, Pair 6/genetics , Gene Expression Regulation, Neoplastic/genetics , Prostatic Neoplasms/genetics , RNA, Messenger/metabolism , Transcription Factors/genetics , Alleles , Cell Line, Tumor , Chromosome Mapping , DNA-Binding Proteins/genetics , Epigenomics , Genetic Predisposition to Disease , Genome-Wide Association Study , Histone Code , Histones/metabolism , Homeodomain Proteins/genetics , Humans , Male , Polymorphism, Single Nucleotide , Regulatory Factor X Transcription Factors , Reverse Transcriptase Polymerase Chain Reaction
13.
Methods Mol Biol ; 1311: 317-34, 2015.
Article En | MEDLINE | ID: mdl-25981483

In recent years, the zebrafish has become a critical contributor to various areas of biomedical research, advancing our fundamental understanding of biomedicine and helping discover candidate therapeutics for human diseases. Nevertheless, to further extend the power of this important model organism requires a robust and simple-to-use genome editing platform that will enable targeted gene knockouts and introduction of specific mutations identified in human diseases into the zebrafish genome. We describe here protocols for creating insertion or deletion (indel) mutations or precise sequence modifications in zebrafish genes using customizable CRISPR-Cas9 RNA-guided nucleases (RGNs). These methods can be easily implemented in any lab and may also potentially be extended for use in other organisms.


CRISPR-Associated Proteins/metabolism , CRISPR-Cas Systems/genetics , Deoxyribonucleases/metabolism , Genetic Engineering/methods , Mutagenesis , RNA/genetics , Zebrafish/genetics , Animals , Embryo, Nonmammalian/metabolism , Genetic Vectors/genetics , Mutation , Zebrafish/embryology
14.
Clin Exp Pharmacol Physiol ; 42(12): 1275-86, 2015 Dec.
Article En | MEDLINE | ID: mdl-26743678

Hemangioblast, including primitive hematopoietic progenitor cells, play an important role in hematopoietic development, however, the underlying mechanism for the propagation of hematopoietic progenitor cells remains elusive. A variety of regulatory molecules activated in early embryonic development play a critical role in the maintenance of function of hematopoietic progenitor cells. Homeobox transcription factors are an important class of early embryonic developmental regulators determining hematopoietic development. However, the effect of homeobox protein Hox-B4 (HOXB4) ectopic expression on the development of hemangioblasts has not been fully addressed. This study aimed to investigate the role of Hoxb4a, an ortholog gene of HOXB4 in zebrafish, in the hematopoietic development in zebrafish. A transgenic zebrafish line was established with Cre-loxP system that stably overexpressed enhanced green fluorescent protein (EGFP)-tagged Hoxb4a protein under the control of hemangioblast-specific lmo2 promoter. Overexpression of Hoxb4a in the development of hemangioblasts resulted in a considerable increase in the number of stem cell leukemia (scl) and lmo2-positive primitive hematopoietic progenitor cells occurring in the posterior intermediate cell mass (ICM). Interestingly, Hoxb4a overexpression also disrupted the development of myelomonocytes in the anterior yolk sac and the posterior ICM, without affecting erythropoiesis in the posterior ICM. Taken together, these results indicate that Hoxb4a favours the development of hematopoietic progenitor cells originated from hemangioblasts in vivo.


Ectopic Gene Expression , Embryonic Development/genetics , Hemangioblasts/metabolism , Hematopoiesis/genetics , Homeodomain Proteins/genetics , Zebrafish Proteins/genetics , Zebrafish/embryology , Zebrafish/genetics , Animals , Animals, Genetically Modified , Base Sequence , Gene Expression Regulation, Developmental , LIM Domain Proteins/genetics , Molecular Sequence Data , Promoter Regions, Genetic/genetics , Recombination, Genetic , Transcription Factors/genetics
15.
Methods Enzymol ; 546: 21-45, 2014.
Article En | MEDLINE | ID: mdl-25398334

CRISPR RNA-guided nucleases have recently emerged as a robust genome-editing platform that functions in a wide range of organisms. To reduce off-target effects of these nucleases, we developed and validated a modified system that uses truncated guide RNAs (tru-gRNAs). The use of tru-gRNAs leads to decreases in off-target effects and does not generally compromise the on-target efficiencies of these genome-editing nucleases. In this chapter, we describe guidelines for identifying potential tru-gRNA target sites and protocols for measuring the on-target efficiencies of CRISPR RNA-guided nucleases in human cells.


CRISPR-Cas Systems , Endonucleases/metabolism , Gene Targeting , Genome, Human , RNA, Guide, Kinetoplastida/genetics , Base Sequence , CRISPR-Associated Proteins/metabolism , Cell Line , Clustered Regularly Interspaced Short Palindromic Repeats , Humans , Molecular Sequence Data , Mutagenesis , RNA, Guide, Kinetoplastida/metabolism
16.
Nat Biotechnol ; 32(3): 279-284, 2014 Mar.
Article En | MEDLINE | ID: mdl-24463574

Clustered, regularly interspaced, short palindromic repeat (CRISPR) RNA-guided nucleases (RGNs) are highly efficient genome editing tools. CRISPR-associated 9 (Cas9) RGNs are directed to genomic loci by guide RNAs (gRNAs) containing 20 nucleotides that are complementary to a target DNA sequence. However, RGNs can induce mutations at sites that differ by as many as five nucleotides from the intended target. Here we report that truncated gRNAs, with shorter regions of target complementarity <20 nucleotides in length, can decrease undesired mutagenesis at some off-target sites by 5,000-fold or more without sacrificing on-target genome editing efficiencies. In addition, use of truncated gRNAs can further reduce off-target effects induced by pairs of Cas9 variants that nick DNA (paired nickases). Our results delineate a simple, effective strategy to improve the specificities of Cas9 nucleases or paired nickases.


Bacterial Proteins/genetics , CRISPR-Associated Proteins/genetics , Endonucleases/genetics , RNA, Guide, Kinetoplastida/genetics , Base Sequence , CRISPR-Associated Proteins/metabolism , DNA/chemistry , DNA/genetics , DNA/metabolism , Endonucleases/chemistry , Endonucleases/metabolism , Humans , Molecular Sequence Data , RNA, Guide, Kinetoplastida/chemistry , RNA, Guide, Kinetoplastida/metabolism
17.
Nat Methods ; 10(10): 977-9, 2013 Oct.
Article En | MEDLINE | ID: mdl-23892898

Short guide RNAs (gRNAs) can direct catalytically inactive CRISPR-associated 9 nuclease (dCas9) to repress endogenous genes in bacteria and human cells. Here we show that single or multiple gRNAs can direct dCas9 fused to a VP64 transcriptional activation domain to increase expression of endogenous human genes. This proof-of-principle work shows that clustered regularly interspaced short palindromic repeat (CRISPR)-Cas systems can target heterologous effector domains to endogenous sites in human cells.


Clustered Regularly Interspaced Short Palindromic Repeats , RNA Editing , Recombinant Fusion Proteins/genetics , Transcriptional Activation , Vascular Endothelial Growth Factor A/genetics , Bacterial Proteins/genetics , HEK293 Cells , Humans , Ribonucleases/genetics , Streptococcus pyogenes/genetics , RNA, Small Untranslated
18.
PLoS One ; 8(7): e68708, 2013.
Article En | MEDLINE | ID: mdl-23874735

We have previously reported a simple and customizable CRISPR (clustered regularly interspaced short palindromic repeats) RNA-guided Cas9 nuclease (RGN) system that can be used to efficiently and robustly introduce somatic indel mutations in endogenous zebrafish genes. Here we demonstrate that RGN-induced mutations are heritable, with efficiencies of germline transmission reaching as high as 100%. In addition, we extend the power of the RGN system by showing that these nucleases can be used with single-stranded oligodeoxynucleotides (ssODNs) to create precise intended sequence modifications, including single nucleotide substitutions. Finally, we describe and validate simple strategies that improve the targeting range of RGNs from 1 in every 128 basepairs (bps) of random DNA sequence to 1 in every 8 bps. Together, these advances expand the utility of the CRISPR-Cas system in the zebrafish beyond somatic indel formation to heritable and precise genome modifications.


CRISPR-Cas Systems , Genome , Zebrafish/genetics , Animals , Base Sequence , CRISPR-Associated Proteins/chemistry , CRISPR-Associated Proteins/genetics , Genetic Engineering , Germ-Line Mutation , INDEL Mutation , Molecular Sequence Data , Mutagenesis, Insertional , Mutation Rate , Oligonucleotides/chemistry , Oligonucleotides/genetics , Sequence Alignment
19.
Nat Biotechnol ; 31(9): 822-6, 2013 Sep.
Article En | MEDLINE | ID: mdl-23792628

Clustered, regularly interspaced, short palindromic repeat (CRISPR) RNA-guided nucleases (RGNs) have rapidly emerged as a facile and efficient platform for genome editing. Here, we use a human cell-based reporter assay to characterize off-target cleavage of CRISPR-associated (Cas)9-based RGNs. We find that single and double mismatches are tolerated to varying degrees depending on their position along the guide RNA (gRNA)-DNA interface. We also readily detected off-target alterations induced by four out of six RGNs targeted to endogenous loci in human cells by examination of partially mismatched sites. The off-target sites we identified harbored up to five mismatches and many were mutagenized with frequencies comparable to (or higher than) those observed at the intended on-target site. Our work demonstrates that RGNs can be highly active even with imperfectly matched RNA-DNA interfaces in human cells, a finding that might confound their use in research and therapeutic applications.


CRISPR-Associated Proteins/genetics , Endonucleases/genetics , Genetic Engineering/methods , Mutagenesis/genetics , Base Sequence , HEK293 Cells , Humans , K562 Cells , Molecular Sequence Data
20.
Nat Methods ; 10(3): 243-5, 2013 Mar.
Article En | MEDLINE | ID: mdl-23396285

Artificial activators designed using transcription activator-like effector (TALE) technology have broad utility, but previous studies suggest that these monomeric proteins often exhibit low activities. Here we demonstrate that TALE activators can robustly function individually or in synergistic combinations to increase expression of endogenous human genes over wide dynamic ranges. These findings will encourage applications of TALE activators for research and therapy, and guide design of monomeric TALE-based fusion proteins.


Genetic Engineering/methods , MicroRNAs/genetics , Transcription Factors/genetics , Transcriptional Activation , Vascular Endothelial Growth Factor A/genetics , Binding Sites , Cell Culture Techniques , Fibroblasts/metabolism , HEK293 Cells , Humans , Plasmids , Promoter Regions, Genetic , Reverse Transcriptase Polymerase Chain Reaction , Tandem Repeat Sequences , Transfection , Xanthomonas , Zinc Fingers/genetics
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