Precision gene editing technologies based on CRISPR/Cas9: a review / 生物工程学报

Gene editing technology is a genetic operation technology that can modify the DNA sequence at the genomic level. The precision gene editing technology based on CRISPR/Cas9 system is a gene editing technology that is easy to operate and widely used. Unlike the traditional CRISPR/Cas9 system, the precision gene editing technology can perform site-directed mutation of genes without DNA template. This review summarizes the recent development of precision gene editing technology based on CRISPR/Cas9, and prospects the challenges and opportunities of this technology.

Human 8-cell embryos enable efficient induction of disease-preventive mutations without off-target effect by cytosine base editor

Approximately 140 million people worldwide are homozygous carriers of APOE4 (ε4), a strong genetic risk factor for late onset familial and sporadic Alzheimer's disease (AD), 91% of whom will develop AD at earlier age than heterozygous carriers and noncarriers. Susceptibility to AD could be reduced by targeted editing of APOE4, but a technical basis for controlling the off-target effects of base editors is necessary to develop low-risk personalized gene therapies. Here, we first screened eight cytosine base editor variants at four injection stages (from 1- to 8-cell stage), and found that FNLS-YE1 variant in 8-cell embryos achieved the comparable base conversion rate (up to 100%) with the lowest bystander effects. In particular, 80% of AD-susceptible ε4 allele copies were converted to the AD-neutral ε3 allele in human ε4-carrying embryos. Stringent control measures combined with targeted deep sequencing, whole genome sequencing, and RNA sequencing showed no DNA or RNA off-target events in FNLS-YE1-treated human embryos or their derived stem cells. Furthermore, base editing with FNLS-YE1 showed no effects on embryo development to the blastocyst stage. Finally, we also demonstrated FNLS-YE1 could introduce known protective variants in human embryos to potentially reduce human susceptivity to systemic lupus erythematosus and familial hypercholesterolemia. Our study therefore suggests that base editing with FNLS-YE1 can efficiently and safely introduce known preventive variants in 8-cell human embryos, a potential approach for reducing human susceptibility to AD or other genetic diseases.

CRISPR-mediated base editing in mice using cytosine deaminase base editor 4

BACKGROUND: Many human genetic diseases arise from point mutations. These genetic diseases can theoretically be corrected through gene therapy. However, gene therapy in clinical application is still far from mature. Nearly half of the pathogenic single-nucleotide polymorphisms (SNPs) are caused by G:C>A:T or T:A>C:G base changes and the ideal approaches to correct these mutations are base editing. These CRISPR-Cas9-mediated base editing does not leave any footprint in genome and does not require donor DNA sequences for homologous recombination. These base editing methods have been successfully applied to cultured mammalian cells with high precision and efficiency, but BE4 has not been confirmed in mice. Animal models are important for dissecting pathogenic mechanism of human genetic diseases and testing of base correction efficacy in vivo. Cytidine base editor BE4 is a newly developed version of cytidine base editing system that converts cytidine (C) to uridine (U). RESULTS: In this study, BE4 system was tested in cells to inactivate GFP gene and in mice to introduce single-base substitution that would lead to a stop codon in tyrosinase gene. High percentage albino coat-colored mice were obtained from black coat-colored donor zygotes after pronuclei microinjection. Sequencing results showed that expected base changes were obtained with high precision and efficiency (56.25%). There are no off-targeting events identified in predicted potential off-target sites. CONCLUSIONS: Results confirm BE4 system can work in vivo with high precision and efficacy, and has great potentials in clinic to repair human genetic mutations.

En homenaje al doctor Carlos Alfonso Mejía Pavony: Memoria y legado

"El maestro que camina, a la prestigiosa sombra de un templo, en medio de sus discípulos, no les da de su sabiduría, sino, que les transmite de su fe y de su amor, su disfrutar en la búsqueda. Pues si él, es verdaderamente sabio, él sabe que, no podrá hacerlos entrar en la casa de su sabiduría; él los conducirá, no obstante, hasta el umbral de tu propio espíritu". El Profeta (Gibran Jalil Gibran, 1923).

Continuous publication / Publicación continua

Continuous publication is defined as the publication of manuscripts in a scientific journal without periodicity and continuously, in order to accelerate the publication of results from author's research. In this edition model, the manuscript is published immediately its acceptance and after being evaluated by peer reviewers. This way of edition has been used since 2013 by several scientific journals world wide, and have been accepted by editors with high satisfaction in terms of improved production workflow, decreased dependence on production deadlines and increased speed of research dissemination.

Recent advances and applications of base editing systems / 生物工程学报

The CRISPR system is able to accomplish precise base editing in genomic DNA, but relies on the cellular homology-directed recombination repair pathway and is therefore extremely inefficient. Base editing is a new genome editing technique developed based on the CRISPR/Cas9 system. Two base editors (cytosine base editor and adenine base editor) were developed by fusing catalytically disabled nucleases with different necleobase deaminases. These two base editors are able to perform C>T (G>A) or A>G (T>C) transition without generating DNA double-stranded breaks. The base editing technique has been widely used in gene therapy, animal models construction, precision animal breeding and gene function analysis, providing a powerful tool for basic and applied research. This review summarized the development process, technical advantages, current applications, challenges and perspectives for base editing technique, aiming to help the readers better understand and use the base editing technique.

Proportion of women on the editorial committees of dental journals in the world / Proporção de mulheres nos comitês editoriais de revistas odontológicas no mundo

Objective: Despite the increase in the female contribution to careers in the health sector, Dentistry has shown slow progress towards gender equality. The objective of this study was to quantify the proportion of women in the editorial committees of dental journals in the world. Material and Methods: Dental journals published in the world were compiled, which met inclusion criteria: dental journals indexed to Scopus in their 2020 edition, access to the composition of the editorial committee. Non-current journals, without access to their website, journals not classified in a quartile, and journals with publishers outside their country of origin, were excluded. The selection of journals was carried out from January 11 to 19, 2021. The analysis variables were the composition of the editorial committee, dental specialty according to the SJR category and the title of the journal, quartile of the journal, and country of origin of the editorial headquarters. Results: One hundred eighty nine journals were identified. Women represented 22.91% for the position of director or editor-in-chief. With respect to associate editors and members of the editorial board, 24.76% and 22.91% were women, respectively. Likewise, greater female participation was observed in Q2 and Q1 journals and in thematic areas of Geriatric Dentistry, Dental Education, Dental Public Health, and Basic Sciences. Conclusion: The findings demonstrate the low proportion of women on the editorial boards of dental journals in the world (AU)

Objetivo: Apesar do aumento da contribuição feminina para as carreiras no setor da saúde, a odontologia tem apresentado avanços lentos em direção à equidade de gênero. O objetivo deste estudo foi quantificar a proporção de mulheres nos comitês editoriais de periódicos odontológicos no mundo. Material e Métodos: Foram compilados periódicos odontológicos publicados no mundo, que atenderam aos critérios de inclusão: periódicos odontológicos indexados ao Scopus em sua edição de 2020, acesso à composição do comitê editorial. Foram excluídos os periódicos não atuais, sem acesso ao site, os periódicos não classificados em quartil e os periódicos com editoras fora do país de origem. A seleção dos periódicos foi realizada no período de 11 a 19 de janeiro de 2021. As variáveis de análise foram a composição do comitê editorial, especialidade odontológica de acordo com a categoria SJR e o título do periódico, quartil do periódico e país de origem da sede do editorial. Resultados:Cento e oitenta e nove periódicos foram identificados. As mulheres representaram 22,91% para o cargo de diretora ou redatora-chefe. Em relação aos editores associados e membros do comitê editorial, 24,76% e 22,91% eram mulheres, respectivamente. Da mesma forma, foi observada maior participação feminina nos periódicos Q2 e Q1 e nas áreas temáticas de Odontologia Geriátrica, Educação Odontológica, Saúde Pública Odontológica e Ciências Básicas. Conclusão: Os achados demonstram a baixa proporção de mulheres nos conselhos editoriais de periódicos odontológicos no mundo. (AU)

Ver y leer. Anotaciones sobre la imprenta de la Biblioteca Nacional de Colombia y los clisés de la Campaña nacional contra el analfabetismo / To see and to read. Annotations about the press of the National Library of Colombia and the stereotypes of the national campaign against the illiteracy / Ver e ler. Anotações sobre a imprensa da Biblioteca Nacional da Colômbia e as pranchas de impressão da campanha nacional contra o analfabetismo

Resumen Introducción: este artículo realiza una aproximación sociohistórica a las contribuciones de la imprenta de la Biblioteca Nacional de Colombia a los procesos de alfabetización en la primera mitad del siglo XX en el país. Objetivo: se examina el papel que desempeñó la Imprenta de la Biblioteca Nacional de Colombia en la Campaña nacional contra el analfabetismo liderada por el Ministerio de Educación Nacional durante 1930-1960. Materiales y métodos: metodológicamente se efectuó un análisis tipográfico, iconográfico y material a un acervo de publicaciones que se encontraron a partir de la colección de 28 clisés de impresión, encontrados en el sótano de la Biblioteca en el 2015. Resultados: los clisés fueron una herramienta de reproductibilidad y repetición, constituyéndose en prototipo y arquetipo de la Modernidad y la mecanización. Asimismo, la comprensión de las planchas de impresión, en tanto fenómenos sociomateriales complejos, implica una perspectiva que trasciende la fijación por la objetualidad técnica del oficio de la impresión y amplía su interpretación como resultado de esfuerzos humanos e institucionales. Conclusiones: las técnicas de impresión y los procedimientos de transformación e innovación tuvieron incidencia en la cultura impresa configurando un sistema técnico que privilegió la alfabetización. De esta manera se debe pensar de forma relacional los aportes de las artes gráficas al desarrollo de proyectos editoriales alfabetizadores liderados por el Estado-instructor a lo largo del período de estudio.

Abstract Introduction: this article makes a sociohistorical approach to the contributions of the printing press of the National Library of Colombia to the literacy processes in the first half of the 20th century in the country. Objective: the role played by the Printing Office of the National Library of Colombia in the national Campaign against illiteracy led by the Ministry of National Education during 19301960 is examined. Materials and methods: methodologically, a typographic, iconographic and material analysis was carried out on a collection of publications that were found from the collection of 28 printing cliches, found in the basement of the Library in 2015. Results: the cliches were a tool of reproducibility and repetition, becoming a prototype and archetype of Modernity and mechanization. Likewise, the understanding of printing plates, as complex sociomaterial phenomena, implies a perspective that transcends the fixation for the technical objectuality of the printing trade and broadens its interpretation as a result of human and institutional efforts. Conclusions: the printing techniques and the transformation and innovation procedures had an impact on the printed culture, configuring a technical system that privileged literacy. In this way, the contributions of graphic arts to the development of literacy publishing projects led by the State-instructor throughout the study period should be thought in a relational way.

Resumo Introdução: este artigo faz uma abordagem sócio-histórica das contribuições da imprensa da Biblioteca Nacional da Colômbia para os processos de alfabetização na primeira metade do século XX no país. Objetivo: examina-se o papel desempenhado pela Imprensa da Biblioteca Nacional da Colômbia na Campanha nacional contra o analfabetismo dirigida pelo Ministério da Educação Nacional durante 1930-1960. Materiais e métodos: metodologicamente, foi realizada uma análise tipográfica, iconográfica e material de uma coleção de publicações que se encontravam no acervo de 28 clichês impressos, encontrados no porão da Biblioteca em 2015. Resultados: os clichês foram uma ferramenta de reprodutibilidade e repetição, tornandose protótipo e arquétipo da Modernidade e da mecanização. Da mesma forma, a compreensão das chapas de impressão, como fenômenos sociomateriais complexos, implica uma perspectiva que transcende a fixação pela objetualidade técnica da tipografia e amplia sua interpretação a partir de esforços humanos e institucionais. Conclusões: as técnicas de impressão e os procedimentos de transformação e inovação impactaram a cultura impressa, configurando um sistema técnico que privilegiava o letramento. Desta forma, as contribuições das artes gráficas para o desenvolvimento de proJetos editoriais de alfabetização liderados pelo Estado-instrutor ao longo do período de estudos devem ser pensadas de forma relacional.

Application of base editors in the treatment of genetic disorders / 药学学报

To date, CRISPR/Cas systems represent the most widely used tool for genome editing; however, its application scope for gene therapy has been largely limited due to its limited efficiency in activating homology-directed repair for DNA and off-target effect. Base editing is a new CRISPR/Cas-based genome-editing strategy, which allows single nucleotide to be precisely corrected in a narrow window scope on the target DNA or RNA by taking advantage of different nucleobase deaminases. Base editors include cytosine base editors (CBEs) and adenine base editors (ABEs), which can induce the conversions from C·G to T·A and A·T to G·C, respectively. Base editors work independently of double-strand DNA breaks (DSBs) and DNA donor templates, and thus they are extensively adopted for a wide range of therapeutic applications for genetic diseases, largely owing to their high efficiency and great specificity. In this review, we summarize the development of base editors and their potentials as therapeutic drugs for treating genetic diseases, and future outlooks are also discussed.

[Carta al Editor] / Carta al Editor

Teniendo en cuenta que el artículo de Barrera-Dussán et al.(1), "Prevalencia y determinantes sociales de malnutrición en menores de 5 años afiliados al Sistema de Selección de Beneficiarios para Programas Sociales (SISBEN) del área urbana del municipio de Palermo en Colombia 2017" publicado en el último número de la Revista Universidad y Salud Año 2018 Septiembre-Diciembre Volumen 20 Número 3 Páginas 236-246; no solamente será leído a nivel nacional/colombiano, sino a nivel internacional/mundial, mi comentario más que el desconocer las cifras obtenidas en este excelente artículo original, es tener la oportunidad de que con lo solicitado aquí, pueda aportar mayor e importante información.

¿Temor de compartir los datos?: La necesidad de una ciencia más abierta / Fear of sharing the data?: The need for a more open science

Es una editorial

It is a editorial

Summary of the 2019 Working Conference of Editor-in-Chief of Chinese Journal of Burns / 中华烧伤杂志

The Working Conference of Editor-in-Chief, sponsored by the Editorial Committee of Chinese Journal of Burns, was successfully held in Guiyang, Guizhou Province, from April 10th to 12th 2019. Consultant for life, honorary editor-in-chief, editor-in-chief, deputy editor-in-chief, and members of the standing committee gave effective proposal involving construction and development of journal, planning scheme for 20th anniversary celebration of journal, and future work plan.

Advice to the author: a scientific approach to the issue of paper modification / 中国实用护理杂志

If a paper can be accepted by a journal and finally published, it must go through the 'modification'stage, and the editor will write the modification opinion according to the specific situation of the paper. When the author receives the editor′s modification opinion, he must be treated correctly because it is a matter of paper'life and death'. However, the editor′s modification opinion cannot be fully authoritative, although the author should attach great importance to it, he should treat it correctly. The author should communicate with the editor to improve the quality of the paper.

Cultura y sociedad: Próspero Calderón y su legado para las artes, letras y publicaciones costarricenses / Culture and society: Prospero Calderón and his legacy for Costa Rican arts, letters and publications

Resumen Próspero Calderón (1862-1934) será el primer costarricense que se dedique a la profesión de editor; asimismo, será fotógrafo, docente, diseñador y precursor de las Artes gráficas en el país. Bajo sus ideales de promoción de la cultura se fundan las primeras publicaciones costarricenses en formato de revista: Costa Rica Ilustrada y Páginas Ilustradas, presentando en sus páginas fotografías de H.N. Rudd, Manuel Gómez Miralles y Amando Céspedes, entre otros, así como textos de Joaquín García Monge, Justo A. Facio, Carmen Lyra y Lisímaco Chavarría. Su aporte es imprescindible en el estudio de la sociedad y del arte costarricense en la transición del s. XIX al s. XX. Por lo anterior, para la realización de esta investigación, se recurrió a la Metodología Histórica, desarrollada a partir de las etapas heurística y hermenéutica, para finalizar con una propuesta teórica bajo la figura de Biografía histórica.

Abstract Prospero Calderón (1862-1934) will be the first Costa Rican to devote himself to the profession of editor; Likewise he will be photographer, teacher, designer and precursor of the graphic arts in the country. Under its ideals for the promotion of culture, the first Costa Rican publications are published in a magazine format: Costa Rica Ilustrada and Páginas Ilustradas, featuring on its pages photographs of H.N. Rudd, Manuel Gómez Miralles and Amando Céspedes, among others, as well as texts by Joaquín García Monje, Justo A. Facio, Carmen Lyra and Lisímaco Chavarría. His contribution is essential in the study of Costa Rican society and art in the transition of the s. XIX to s. XX. In order to carry out this research, was used the Historical Methodology, developed from the heuristic and hermeneutic stages, to conclude with a theoretical proposal under the figure of Historical Biography.

Carta al Editor: Manejo del Trauma de Cráneo sin Monitoreo de la Presión Intracraneal / Letter to the Editor: Head Trauma Management without Intracranial Pressure Monitoring

Cada año millones de personas alrededor del mundo sufren de Trauma de Cráneo (TEC), una sustancial proporción han muerto o se mantienen discapacitados [1]. El TEC provoca una lesión estructural y/o una disrupción fisiológica de la función cerebral; aunque en gran parte el daño cerebral definitivo depende del trauma per se, cambios inflamatorios pos-traumáticos también contribuyen al resultado final . La Universidad de Washington, a través del Dr. Randall M Chesnut y su equipo nos ha hecho llegar al Hospital de Especialidades José Carrasco Arteaga una placa de reconocimiento por el trabajo que hasta hoy se ha realizado en la Unidad de Cuidados Intensivos (UCI) del hospital y el Servicio de Neurocirugía, con la participación activa de las Dras. Soraya Puertas y Katy Trelles y con el apoyo del Dr. Marco Rivera, Coordinador General de Investigación del Hospital. Esperamos que los resultados de este estudio sirvan para optimizar el cuidado de nuestros pacientes, objetivo final de todo esfuerzo médico.

Medical Ethics Principles in the Writing and Review of Medical Journals / 中国医学伦理学

The basic principles of medical ethics included respect and autonomy,beneficial and nonmaleficence,informed consent and confidentiality,impartiality and mutual assistance.During medical journal editing,medical ethics principles should be strictly applied.Focused on two types of medical thesis,medical scientific research and clinical trials,this paper concluded the ethics issues related to experimental animals,cells and gene researches,all these should be noticed in manuscripts.Meanwhile,this paper analyzed the ethics principles about contrast set and the use of placebo that should be abided in clinical trial,and the respects of patients'privacy during clinical observation,etc.Some review key points were put forward from the perspective of editors.

The crystal structure of Ac-AChBP in complex with α-conotoxin LvIA reveals the mechanism of its selectivity towards different nAChR subtypes

The α3* nAChRs, which are considered to be promising drug targets for problems such as pain, addiction, cardiovascular function, cognitive disorders etc., are found throughout the central and peripheral nervous system. The α-conotoxin (α-CTx) LvIA has been identified as the most selective inhibitor of α3β2 nAChRs known to date, and it can distinguish the α3β2 nAChR subtype from the α6/α3β2β3 and α3β4 nAChR subtypes. However, the mechanism of its selectivity towards α3β2, α6/α3β2β3, and α3β4 nAChRs remains elusive. Here we report the co-crystal structure of LvIA in complex with Aplysia californica acetylcholine binding protein (Ac-AChBP) at a resolution of 3.4 Å. Based on the structure of this complex, together with homology modeling based on other nAChR subtypes and binding affinity assays, we conclude that Asp-11 of LvIA plays an important role in the selectivity of LvIA towards α3β2 and α3/α6β2β3 nAChRs by making a salt bridge with Lys-155 of the rat α3 subunit. Asn-9 lies within a hydrophobic pocket that is formed by Met-36, Thr-59, and Phe-119 of the rat β2 subunit in the α3β2 nAChR model, revealing the reason for its more potent selectivity towards the α3β2 nAChR subtype. These results provide molecular insights that can be used to design ligands that selectively target α3β2 nAChRs, with significant implications for the design of new therapeutic α-CTxs.

Effective gene editing by high-fidelity base editor 2 in mouse zygotes

Targeted point mutagenesis through homologous recombination has been widely used in genetic studies and holds considerable promise for repairing disease-causing mutations in patients. However, problems such as mosaicism and low mutagenesis efficiency continue to pose challenges to clinical application of such approaches. Recently, a base editor (BE) system built on cytidine (C) deaminase and CRISPR/Cas9 technology was developed as an alternative method for targeted point mutagenesis in plant, yeast, and human cells. Base editors convert C in the deamination window to thymidine (T) efficiently, however, it remains unclear whether targeted base editing in mouse embryos is feasible. In this report, we generated a modified high-fidelity version of base editor 2 (HF2-BE2), and investigated its base editing efficacy in mouse embryos. We found that HF2-BE2 could convert C to T efficiently, with up to 100% biallelic mutation efficiency in mouse embryos. Unlike BE3, HF2-BE2 could convert C to T on both the target and non-target strand, expanding the editing scope of base editors. Surprisingly, we found HF2-BE2 could also deaminate C that was proximal to the gRNA-binding region. Taken together, our work demonstrates the feasibility of generating point mutations in mouse by base editing, and underscores the need to carefully optimize base editing systems in order to eliminate proximal-site deamination.

Correction of β-thalassemia mutant by base editor in human embryos

β-Thalassemia is a global health issue, caused by mutations in the HBB gene. Among these mutations, HBB -28 (A>G) mutations is one of the three most common mutations in China and Southeast Asia patients with β-thalassemia. Correcting this mutation in human embryos may prevent the disease being passed onto future generations and cure anemia. Here we report the first study using base editor (BE) system to correct disease mutant in human embryos. Firstly, we produced a 293T cell line with an exogenous HBB -28 (A>G) mutant fragment for gRNAs and targeting efficiency evaluation. Then we collected primary skin fibroblast cells from a β-thalassemia patient with HBB -28 (A>G) homozygous mutation. Data showed that base editor could precisely correct HBB -28 (A>G) mutation in the patient's primary cells. To model homozygous mutation disease embryos, we constructed nuclear transfer embryos by fusing the lymphocyte or skin fibroblast cells with enucleated in vitro matured (IVM) oocytes. Notably, the gene correction efficiency was over 23.0% in these embryos by base editor. Although these embryos were still mosaic, the percentage of repaired blastomeres was over 20.0%. In addition, we found that base editor variants, with narrowed deamination window, could promote G-to-A conversion at HBB -28 site precisely in human embryos. Collectively, this study demonstrated the feasibility of curing genetic disease in human somatic cells and embryos by base editor system.