Application of CRISPR-Cas9 to interrogate novel gene functions in cutaneous melanoma

Melanoma accounts for 3% of skin neoplasms and is the leading cause of death from skin disorders worldwide. The high mortality rate associated with this disease stems from the high capacity of melanoma patients to develop metastases and treatment relapse with inhibitors of the MAPK signaling pathway (such as BRAF inhibitors), commonly used in melanoma therapy. Thus, the investigation of genes involved in the mechanisms of melanoma development is essential for new and more effective therapeutic strategies. Hence, we describe in this thesis two projects involving the genes SIN3B and IRF4 as possible biomarkers for cutaneous melanoma. Initially, through bioinformatics analyses performed by our group, an upregulation of SIN3B was found in metastatic melanomas. This result together with the understanding of SIN3B role in regulating gene expression and oncogenic transformation, prompted us to describe in this thesis some mechanisms by which SIN3B may influence melanoma development. We then sought to characterize the gene function using SIN3B-deleted cells, generated by the CRISPR-Cas9 methodology. Initially, we observed increased SIN3B expression in BRAF-mutant metastatic melanomas, where we noted that the long splicing variant of the gene (NM_001297595.1) was effectively prevalent in melanomas. Subsequently, we designed gRNAs between the exons 2 and 3 of the human SIN3B gene and engineered three knockout clones and three control clones (containing empty lentiCRISPRv2 plasmid) from different melanoma cell lines (SKMEL28, A2058, and A375). Through functional analyses, it was observed that the absence of the gene did not interfere in the proliferation of tumor cells; however, it led to a decrease in invasive properties. These results were verified by Boyden chamber assays and transcriptome analysis (total RNA sequencing of deleted cells), where a decrease in migration and motility pathways was observed. Additionally, a screening of synthetically lethal genes with SIN3B was performed with a genome wide CRISPR library. These results showed that USP7 and STK11 genes, which belong to the FoxO signaling pathway, were essential in SIN3B-depleted melanoma cells. Finally, through a collaborative project with the Wellcome Trust Sanger Institute, previous large-scale sequencing analyses demonstrated that deletion of the IRF4 gene was lethal for melanoma cells. Accordingly, we performed IRF4 silencing in vitro and noticed that the lack of IRF4 promotes cell death and apoptosis, independently of MYC and MITF, known in the literature to be downstream targets of this gene. Therefore, these data suggest that IRF4 plays a vital role in melanoma cell survival. Taken together, both works herein described in this thesis demonstrate how CRISPR-Cas9 can be applied to study the functions and mechanisms of genes involved in melanoma progression, collectively helping in the development of more effective therapeutic strategies for this tumor

O melanoma representa 3% dos tipos de neoplasias cutâneas e é a maior causa das mortes por distúrbios de pele no mundo. A alta taxa de mortalidade associada à essa doença advém da alta capacidade de pacientes com melanoma desenvolverem metástases, e apresentarem recidiva após tratamento com inibidores da via de sinalização MAPK (como da proteína BRAF), comumente utilizados no tratamento de pacientes metastáticos. Assim, a investigação de genes envolvidos nos mecanismos de desenvolvimento do melanoma é primordial para novas estratégias terapêuticas mais efetivas. Dessa forma, descrevemos no presente trabalho dois projetos envolvendo os genes SIN3B e IRF4 como possíveis biomarcadores para melanoma cutâneo. Em análises prévias de bioinformática realizados pelo nosso grupo, SIN3B foi identificado tendo maior expressão em melanomas metastáticos. Além disso, diversos estudos mostraram que o gene está envolvido na regulação da expressão gênica e transformação oncogênica. Dessa forma, descrevemos nessa tese alguns mecanismos pelos quais SIN3B pode influenciar no desenvolvimento do melanoma, através da caracterização funcional de células SIN3B-deletadas pela metodologia CRISPR-Cas9. Inicialmente, observamos aumento na expressão de SIN3B em melanomas metastáticos BRAF-mutados, onde notamos que a variante de splicing longa do gene (NM_001297595.1), era efetivamente prevalente em melanomas. Assim, desenhamos sequências de RNA guias entre os éxons 2 e 3 do gene SIN3B humano e, obtivemos três clones knockout e outros três clones controle (contendo plasmídeo vazio) em diferentes linhagens de melanoma (SKMEL28, A2058 e A375), para caracterização funcional. Observou-se que a ausência do gene não interferiu na proliferação das células tumorais, contudo, acarretou na diminuição de processos invasivos. Esses resultados foram averiguados através de ensaios em câmara de Boyden e análises de transcriptoma (sequenciamento de RNA total das células deletadas), onde notou-se diminuição das vias de migração e motilidade. Adicionalmente, um rastreamento de genes sinteticamente letais com SIN3B foi realizado com uma biblioteca de CRISPR capaz de silenciar todo o genoma. Esses resultados mostraram que os genes USP7 e STK11, ambos pertencentes à via de sinalização de FoxO, são essenciais nas células SIN3B deletadas. Por fim, através de um projeto colaborativo com o Wellcome Trust Sanger Institute, análises prévias de sequenciamento de larga escala demonstraram que a deleção do gene IRF4 era letal para células de melanoma. Dessa forma, realizamos o silenciamento de IRF4 in vitro e notamos que a ausência do gene promove morte celular e apoptose, independentemente de MYC e MITF, conhecidos na literatura por serem alvos downstream do gene. Portanto, esses dados sugerem que IRF4 tem um papel importante na sobrevivência de células de melanoma. Em conjunto, ambos trabalhos descritos nessa tese, demonstram como a metodologia CRISPR-Cas9 pode auxiliar no entendimento de processos importantes para a malignidade do melanoma e contribuir para estratégias terapêuticas mais efetivas para esse tumor

Regulating the structure of bacterial cellulose by altering the expression of bcsD using CRISPR/dCas9 / 生物工程学报

Gluconacetobacter xylinus is a primary strain producing bacterial cellulose (BC). In G. xylinus, BcsD is a subunit of cellulose synthase and is participated in the assembly process of BC. A series of G. xylinus with different expression levels of the bcsD gene were obtained by using the CRISPR/dCas9 technique. Analysis of the structural characteristics of BC showed that the crystallinity and porosity of BC changed with the expression of bcsD. The porosity varied from 59.95%-84.05%, and the crystallinity varied from 74.26%-93.75%, while the yield of BC did not decrease significantly upon changing the expression levels of bcsD. The results showed that the porosity of bacterial cellulose significantly increased, while the crystallinity was positively correlated with the expression of bcsD, when the expression level of bcsD was below 55.34%. By altering the expression level of the bcsD gene, obtaining BC with different structures but stable yield through a one-step fermentation of G. xylinus was achieved.

A CRISPR/dCpf1-based transcriptional repression system for Gluconobacter oxydans / 生物工程学报

Gluconobacter oxydans are widely used in industrial due to its ability of oxidizing carbohydrate rapidly. However, the limited gene manipulation methods and less of efficient gene editing tools impose restrictions on its application in industrial production. In recent years, the clustered regularly interspaced short palindromic repeats (CRISPR) system has been widely used in genome editing and transcriptional regulation which improves the efficiency of genome editing greatly. Here we constructed a CRISPR/dCpf1-mediated gene transcriptional repression system, the expression of a nuclease inactivation Cpf1 protein (dCpf1) in Gluconobacter oxydans together with a 19 nt direct repeats showed effective repression in gene transcription. This system in single gene repression had strong effect and the relative repression level had been increased to 97.9%. While it could be applied in multiplex gene repression which showed strong repression ability at the same time. Furthermore, this system was used in the metabolic pathway of L-sorbose and the regulatory of respiratory chain. The development of CRISPR transcriptional repression system effectively covered the shortage of current gene regulation methods in G. oxydans and provided an efficient gene manipulation tool for metabolic engineering modification in G. oxydans.

Crispr-cas9: el debate bioético más allá de la línea germinal / Crispr-cas9: the bioethical debate beyond the germline / Crispr-cas9: o debate bioético mais além da linhagem germinativa

Resumen El sistema CRISPR-Cas9 es una tecnología de edición genética que, además de ampliar las posibilidades en investigación científica, despierta reflexiones asociadas a la dignidad humana, el control biológico, la terapia y la mejora genética. Se revisaron las discusiones bioéticas asociadas a los desafíos y las repercusiones que suscita su aplicación. Como resultado, los cuestionamientos bioéticos tienden a problematizar la aplicación en organismos no humanos, en la investigación básica y en la línea somática y germinal humana. Para concluir, falta incrementar los niveles de seguridad y efectividad para que los beneficios superen los riesgos y, de esta forma, sea posible disminuir las preocupaciones bioéticas y aumentar la credibilidad en el uso de la técnica.

Abstract The CRISPR-Cas9 system is a genetic editing technology that, in addition to expanding the possibilities for scientific research, promotes reflections associated with human dignity, biological control, therapy, and genetic improvement. Bioethical discussions on the challenges and repercussions of the CRISPR-Cas9 system are reviewed. As a result, bioethical questions tend to problematize the application to non-human organisms, primary research, and the human somatic and germline. In brief, it is necessary to increase the levels of safety and effectiveness so that the benefits outweigh the risks, while reducing bioethical concerns and increasing the credibility of the technique.

Resumo O sistema CRISPR-Cas9 é uma tecnologia de edição de genes que, além de ampliar as possibilidades em pesquisa científica, desperta reflexões associadas com a dignidade humana, o controle biológico, a terapia e o aperfeiçoamento genético. Foram revisadas as discussões bioéticas relacionadas aos desafios e às repercussões que sua aplicação suscita. Como resultado, os questionamentos bioéticos tendem a problematizar a aplicação em organismos não humanos, na pesquisa básica e na linhagem somática e germinativa humana. Para concluir, falta aumentar os níveis de segurança e efetividade para que os benefícios sejam maiores do que os riscos, e assim, seja possível diminuir as preocupações bioéticas e aumentar a credibilidade no uso da técnica.

CRISPR-Cas, el editor de genes / CRISPR, gene editor

El término CRISPR, por su acrónimo en inglés refiere a Clustered Regularly Interspaced Short Palindromic Repeats, es decir, repeticiones palindrómicas cortas, agrupadas y regularmente esparcidas, por sus características en el genoma, pertenece naturalmente al sistema de defensa de bacterias y arqueas. Este ha sido adaptado biotecnológicamente para la edición del ADN de células eucariotas, incluso de células humanas. El sistema CRISPR-Cas para editar genes consta, en forma generalizada, de dos componentes: una proteína nucleasa (Cas) y un ARN guía (sgRNA). La simplicidad del complejo lo hace una herramienta molecular reprogramable capaz de ser dirigida y de editar cualquier sitio en un genoma conocido. Su principal foco son las terapias para enfermedades hereditarias monogénicas y para el cáncer. Sin embargo, además de editor de genes, la tecnología CRISPR se utiliza para edición epigenética, regulación de la expresión génica y método de diagnóstico molecular. Este artículo tiene por objetivo presentar una revisión de las aplicaciones de la herramienta molecular CRISPR-Cas, particularmente en el campo biomédico, posibles tratamientos y diagnósticos, y los avances en investigación clínica, utilizando terapia génica con CRISPR/Cas más relevantes hasta la fecha. (AU)

CRISPR are Clustered Regularly Interspaced Short Palindromic Repeats, which naturally belong to the defense system of bacteria and archaea. It has been biotechnologically adapted for editing the DNA of eukaryotic cells, including human cells. The CRISPR-Cas system for editing genes generally consists of two components, a nuclease protein (Cas) and a guide RNA (sgRNA). The simplicity of the complex makes it a reprogrammable molecular tool capable of being targeted and editing any site in a known genome. Its main focus is therapies for monogenic inherited diseases and cancer. However, in addition to gene editor, CRISPR technology is used for epigenetic editing, regulation of gene expression, and molecular diagnostic methods. This article aims to present a review of the applications of the CRISPR-Cas molecular tool, particularly in the biomedical field, possible treatments and diagnoses, and the advances in clinical research, using the most relevant CRISPR-Cas gene therapy to date. (AU)

Deciphering the functional role of EGR1 in Prostaglandin F2 alpha induced luteal regression applying CRISPR in corpus luteum of buffalo

BACKGROUND: PGF2α is essential for the induction of the corpus luteum regression which in turn reduces progesterone production. Early growth response (EGR) proteins are Cys2-His2-type zinc-finger transcription factor that are strongly linked to cellular proliferation, survival and apoptosis. Rapid elevation of EGR1 was observed after luteolytic dose of PGF2α. EGR1 is involved in the transactivation of many genes, including TGFß1, which plays an important role during luteal regression. METHODS: The current study was conducted in buffalo luteal cells with the aim to better understand the role of EGR1 in transactivation of TGFß1 during PGF2α induced luteal regression. Luteal cells from mid stage corpus luteum of buffalo were cultured and treated with different doses of PGF2α for different time durations. Relative expression of mRNAs encoding for enzymes within the progesterone biosynthetic pathway (3ßHSD, CYP11A1 and StAR); Caspase 3; AKT were analyzed to confirm the occurrence of luteolytic event. To determine if EGR1 is involved in the PGF2α induced luteal regression via induction of TGFß1 expression, we knocked out the EGR1 gene by using CRISPR/Cas9. RESULT: The present experiment determined whether EGR1 protein expression in luteal cells was responsive to PGF2α treatment. Quantification of EGR1 and TGFß1 mRNA showed significant up regulation in luteal cells of buffalo at 12 h post PGF2α induction. In order to validate the role of PGF2α on stimulating the expression of TGFß1 by an EGR1 dependent mechanism we knocked out EGR1. The EGR1 ablated luteal cells were stimulated with PGF2α and it was observed that EGR1 KO did not modulate the PGF2α induced expression of TGFß1. In PGF2α treated EGR1 KO luteal cell, the mRNA expression of Caspase 3 was significantly increased compared to PGF2α treated wild type luteal cells maintained for 12 h. We also studied the influence of EGR1 on steroidogenesis. The EGR1 KO luteal cells with PGF2α treatment showed no substantial difference either in the progesterone concentration or in StAR mRNA expression with PGF2α-treated wild type luteal cells. CONCLUSION: These results suggest that EGR1 signaling is not the only factor which plays a role in the regulation of PGF2α induced TGFß1 signaling for luteolysis.

Application of CRISPR in evolution analysis, detecting and typing, virulence and antibiotic resistance regulation in food-borne pathogens / 生物工程学报

Clustered regularly interspaced short palindromic repeats (CRISPR) and its associated protein gene system can limit the horizontal gene transfer, thereby effectively preventing the invasion of foreign gene elements such as bacteriophages. CRISPR arrays of different bacteria are diverse. Based on the differences in the CRISPR system, this review summarizes the application of CRISPR in food-borne pathogen evolution analysis, detection and typing, virulence and antibiotic resistance in recent years. We also address bacterial detection typing method developed based on the characteristics of CRISPR arrays and the association of CRISPR with virulence and drug resistance of food-borne pathogens. The shortcomings of CRISPR in evolution, detection and typing, virulence and resistance applications are analyzed. In addition, we suggest standardizing CRISPR typing methods, improving and expanding the CRISPR database of pathogenic bacteria, and further exploring the co-evolution relationship between phages and bacteria, to provide references for further exploration of CRISPR functions.

CRISPR/Cas: a Nobel Prize award-winning precise genome editing technology for gene therapy and crop improvement / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Since it was first recognized in bacteria and archaea as a mechanism for innate viral immunity in the early 2010s, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) has rapidly been developed into a robust, multifunctional genome editing tool with many uses. Following the discovery of the initial CRISPR/Cas-based system, the technology has been advanced to facilitate a multitude of different functions. These include development as a base editor, prime editor, epigenetic editor, and CRISPR interference (CRISPRi) and CRISPR activator (CRISPRa) gene regulators. It can also be used for chromatin and RNA targeting and imaging. Its applications have proved revolutionary across numerous biological fields, especially in biomedical and agricultural improvement. As a diagnostic tool, CRISPR has been developed to aid the detection and screening of both human and plant diseases, and has even been applied during the current coronavirus disease 2019 (COVID-19) pandemic. CRISPR/Cas is also being trialed as a new form of gene therapy for treating various human diseases, including cancers, and has aided drug development. In terms of agricultural breeding, precise targeting of biological pathways via CRISPR/Cas has been key to regulating molecular biosynthesis and allowing modification of proteins, starch, oil, and other functional components for crop improvement. Adding to this, CRISPR/Cas has been shown capable of significantly enhancing both plant tolerance to environmental stresses and overall crop yield via the targeting of various agronomically important gene regulators. Looking to the future, increasing the efficiency and precision of CRISPR/Cas delivery systems and limiting off-target activity are two major challenges for wider application of the technology. This review provides an in-depth overview of current CRISPR development, including the advantages and disadvantages of the technology, recent applications, and future considerations.

Rapid screening of single guide RNA targeting pig genome and the harvesting of monoclonal cells by microarray seal / 生物医学工程学杂志

The emergence of regular short repetitive palindromic sequence clusters (CRISPR) and CRISPR- associated proteins 9 (Cas9) gene editing technology has greatly promoted the wide application of genetically modified pigs. Efficient single guide RNA (sgRNA) is the key to the success of gene editing using CRISPR/Cas9 technology. For large animals with a long reproductive cycle, such as pigs, it is necessary to screen out efficient sgRNA

Structure-based optimization and design of CRISPR protein xCas9 / 生物工程学报

Streptococcus pyogenes Cas9 (SpCas9) has become a powerful genome editing tool, but has a limited range of recognizable protospacer adjacent motifs (PAMs) and shows off-target effects. To address these issues, we present a rational approach to optimize the xCas9 mutant derived from SpCas9 by directed evolution. Firstly, energy minimization with the Rosetta program was applied to optimize the three-dimensional structure of Cas9 to obtain the lowest energy conformation. Subsequently, combinatorial mutations were designed based on the mutations sites of xCas9 acquired during the directed evolution. Finally, optimal mutants were selected from the designed mutants by free energy ranking and subjected to experimental verification. A new mutant yCas9 (262A/324R/409N/480K/543D/694L/1219T) with multiple PAM recognition ability and low off-target effects was obtained and verified by DNA cleavage experiments. This mutant recognizes the NG, GAA and GAT PAMs and shows low off-target DNA cleavage activity guided by mismatched sgRNA, thus provides a gene editing tool with potential applications in biomedical field. Furthermore, we performed molecular dynamics simulations on the structures of SpCas9, xCas9 and yCas9 to reveal the mechanisms of their PAM recognition and off-target effects. These may provide theoretical guidance for further optimization and modification of CRISPR/Cas9 proteins.

CRISPR/Cas9 technology in disease research and therapy: a review / 生物工程学报

Genome editing is a genetic manipulation technique that can modify DNA sequences at the genome level, including insertion, knockout, replacement and point mutation of specific DNA fragments. The ultimate principle of genome editing technology relying on engineered nucleases is to generate double-stranded DNA breaks at specific locations in genome and then repair them through non-homologous end joining or homologous recombination. With the intensive study of these nucleases, genome editing technology develops rapidly. The most used nucleases include meganucleases, zinc finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeats associated Cas proteins. Based on introducing the development and principles of above mentioned genome editing technologies, we review the research progress of CRISPR/Cas9 system in the application fields of identification of gene function, establishment of disease model, gene therapy, immunotherapy and its prospect.

CRISPR/Cas-based genome editing in Aspergillus niger / 生物工程学报

Aspergillus niger is a vital industrial workhouse widely used for the production of organic acids and industrial enzymes. This fungus is a crucial cell factory due to its innate tolerance to a diverse range of abiotic conditions, high production titres, robust growth during industrial scale fermentation, and status as a generally recognized as safe (GRAS) organism. Rapid development of synthetic biology and systems biology not only offer powerful approaches to unveil the molecular mechanisms of A. niger productivity, but also provide more new strategies to construct and optimize the A. niger cell factory. As a new generation of genome editing technology, the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR associated (Cas) system brings a revolutionary breakthrough in targeted genome modification for A. niger. In this review, we focus on current advances to the CRISPR/Cas genome editing toolbox, its application on gene modification and gene expression regulation in this fungal. Moreover, the future directions of CRISPR/Cas genome editing in A. niger are highlighted.

Crispr, una herramienta para editar genomas / Crispr, a tool for editing genomes

El artículo se centra en la utilización de la nueva herramienta, CRISPR (repeticiones palindrómicas cortas agrupadas a intervalos regulares), la cual permite editar los genomas de los seres vivos de manera más precisa que otras técnicas; a lo largo del artículo se mencionan trabajos relacionados con la detención de la angiogénesis, cáncer, Sarcoma de Kaposi en inmunodeficiencias, Parkinson, regeneración y modificación genética en humanos, todas estas investigaciones tiene en común la utilización de la herramienta CRISPR. También se comenta las complicaciones éticas que conlleva utilizar esta tecnología en el ADN de células embrionarias humanas, que según diferentes criterios, podrían llevar a generar seres humanos “mejorados”, es decir no solo sin susceptibilidad a enfermedades degenerativas o incurables, sino también modificados en aspectos físicos que no necesariamente estarían ligados a alguna patología.

The article focuses on the use of the new tool, CRISPR (short palindromic repetitions grouped at regular intervals), which allows editing the genomes of living beings more accurately than other techniques; Throughout the article, works related to the arrest of angiogenesis, cancer, Kaposi’s sarcoma in immunodeficiencies, Parkinson’s, regeneration and genetic modification in humans are mentioned, all these investigations have in common the use of the CRISPR tool. You can also comment on the ethical complications that involve using this technology in the DNA of human embryonic cells, which according to different criteria, carry out improved human beings, that is not only without susceptibility to degenerative or incurable diseases, but also modified in physical aspects that are not linked to any pathology.

Innovaciones en la terapia antimicrobiana / Innovations in antimicrobial therapy

Resumen La resistencia microbiana ha llevado a la búsqueda de innovadoras alternativas para su contención y dentro de las más promisorias están el uso de péptidos sintéticos, no sólo por sus características intrínsecas antimicrobianas, sino por las interacciones sinérgicas y antagónicas que presenta con otros mediadores inmunológicos. Estas propiedades han permitido crear péptidos sintéticos reguladores de defensa innata que representan un nuevo enfoque inmunomodulador para el tratamiento de infecciones; sin embargo, sólo los diseñados con alto score antimicrobiano, han demostrado eficacia en estudios clínicos de Fase 3. Debido a su amplio espectro de actividad, un único péptido puede actuar contra bacterias Gram negativas, Gram positivas, hongos, e incluso virus y parásitos, aumentando el interés por investigar estas dinámicas moléculas. Por otra parte, se encuentra el sistema CRISPR, para la edición de genomas bacterianos, permitirá reducir su actividad virulenta y diseñar antimicrobianos basados en nucleasas CRISPR-Cas 9 programables contra dianas específicas, las que representan un promisorio camino en el estudio de nuevas alternativas con alto potencial para eliminar la resistencia a antibióticos de bacterias altamente patógenas. Asimismo, se aborda la terapia con fagos, referida a la acción de virus que infectan bacterias, usados solos o en cocteles para aumentar el espectro de acción de estos, aprovechando su abundancia en la naturaleza, ya que se ha considerado que cada bacteria tiene un virus específico que podría emplearse como potente agente antibacteriano. Finalmente, mientras se usen como principal medio de contención solo tratamientos convencionales antimicrobianos, incluso de manera oportuna y acertada, la microevolución en las bacterias se asegurará de seguir su curso.

Abstract Microbial resistance has led to the search for innovative alternatives to contain it. One of the most promising ones is the use of peptides, not only due to their intrinsically antimicrobial characteristics, but also due to the synergistic and antagonistic interactions they present with other immunological mediators. These properties have enabled the creation of innate immune regulatory peptides, which represent a new immunomodulatory approach to treat infections. However, despite multiple attempts tested, only the designed with a high antimicrobial score have demonstrated effectiveness in phase three clinical trials. Yet, given their exceptionally wide spectrum of activity, a single peptide can have activity against Gram-negative bacterial, Gram-positive bacterial, fungi and even viruses and parasites, increasing the interest in researching these dynamic molecules. Furthermore, the CRISPR system enables the editing of bacterial genomes, which would make it possible to reduce their virulent activity and design antimicrobials based on programmable CRISPR-Cas 9 nucleases against specific targets. This system represent a promising path in the study of new alternatives with high potential to eliminate antibiotic resistance of highly pathogenic bacteria. Likewise, phage therapy, that is, the action of viruses that infect bacteria, used alone or in cocktails to increase their spectrum of action, taking advantage of their abundance in nature, given that it has been considered that each bacterium has a specific virus that it could be used as a potent antibacterial agent. Finally, as long as conventional antimicrobial treatments continue to be used as the main means of containment, even when they are used correctly, the microevolution of bacteria will be itself sure to continue its own path.

Consideraciones sobre el diagnóstico de COVID-19 y el papel del diagnóstico salival / Considerations on the diagnosis of COVID-19 and the role of the salival diagnosis

El nuevo coronavirus SARS-CoV-2 es el agente etiológico de la enfermedad por coronavirus de 2019 (COVID-19), convertida rápidamente en una pandemia, emergencia sanitaria y una crisis de salud pública en los países afectados a lo largo de los cinco continentes. El objetivo de la presente revisión bibliográfica fue describir algunas consideraciones sobre el diagnóstico del COVID-19 y el papel de los diagnósticos salivales. El diagnóstico molecular, la historia clínica, las manifestaciones clínicas, los hallazgos de laboratorio y los imagenológicos, y la prueba viral del ácido nucleico, el diagnóstico serológico, el sistema CRISPR/ Cas13 y la técnica SHERLOCK son elementos del arsenal diagnóstico de esta infección. Éstos son imprescindibles para el trabajo de los profesionales en salud, ya que generar y conocer medidas de identificación diagnóstica, son pilares esenciales, en el intento de mitigar una mayor propagación de esta infección (AU)

The novel coronavirus SARS-CoV-2 is the etiologic agent of the 2019 coronavirus disease (COVID-19), rapidly converted in a pandemic, sanitary emergency and Public Health crisis in the affected countries over the world. The objective of the present bibliographical review was to describe some considerations about the diagnosis of COVID-19 and the role of salivary diagnostics. The molecular diagnosis, the clinical history, the laboratory and imagenologic findings, the nucleic acid viral test, the serologic diagnosis, the CRISPR/Cas13 system, and the SHERLOCK technique, are all elements of the diagnostic arsenal to identify this infection. These elements are indispensables for the health professionals. Generating and knowing the diagnostic identification measures are essential pillars in the attempt of mitigating a greater propagation of this disease (AU)

The luciferase reporter system of the MMP12 endogenous promoter for investigating transcriptional regulation of the human MMP12 gene

Background: Matrix metalloproteinase 12 (MMP12), a member of MMPs, can take lots of roles including extracellular matrix component degradation, viral infection, inflammation, tissue remodeling and tumorigenesis. To explore the transcriptional regulation of MMP12 gene, a sensitive luciferase reporter HEK293 cell line for endogenous MMP12 promoter was generated by CRISPR/Cas9 technology. Results: The HEK293-MMP12-T2A-luciferase-KI cell line was successfully established by CRISPR/Cas9 technology. The sequencing results indicated that one allele of the genome was proven to have a site-directed insertion of luciferase gene and another allele of the genome was confirmed to have additional 48 bp insertion in this cell line. The cell line was further demonstrated to be a sensitive reporter of the endogenous MMP12 promoter by applying transcription factors STAT3, AP-1 and SP-1 to the cell line. The reporter cell line was then screened with bioactive small molecule library, and a small molecule Tanshinone I was found to significantly inhibit the transcriptional activity of MMP12 gene in HEK293-MMP12-T2A-luciferase-KI cell line by luciferase activity assay, which was further confirmed to inhibit the expression of MMP12 mRNA in wild-type HEK293 cells. Conclusions: This novel luciferase knock-in reporter system will be helpful for investigating the transcriptional regulation of MMP12 gene and screening the drugs targeting MMP12 gene.

Advances in gene editing of Corynebacterium glutamate / 生物工程学报

Corynebacterium glutamicum, an important microorganism to produce amino acids and organic acids, has been widely applied in food and medicine fields. Therefore, using editing tools to study the function of unknown genes in C. glutamicum has great significance for systematic development of industrial strain with efficient and novel production capability. Recently, gene editing has been greatly developed. Traditional gene editing based on homologous recombination and gene editing mediated by nuclease are successfully applied in C. glutamicum. Among these, the CRISPR system has been developed to be a main tool used for gene knockout of C. glutamicum due to its advantages of efficiency, simplicity and good target specificity. However, more efficient and reliable knockout system is still urgently demanded, to help develop high-performing strains in industrial application.

Gene edited animal models applied in human disease research / 生物工程学报

Recently, with the development and the continuous improvement of various CRISPR systems represented by CRISPR/Cas9, gene editing technology has been gradually improved, and widely applied to the preparation of animal models of human diseases. The gene edited animal models provide important materials for the study of pathogenesis, pathological process, prevention and treatment of human diseases. At present, the gene edited animal models used in human disease research include mainly the rodent models represented by mice and rats, and large animal models represented by pigs. Among them, rodents differ greatly from humans in all aspects of their bodies and have short life span as well, which cannot provide effective evaluation and long-term tracking for the research and treatment of human diseases. On the other hand, pig is closer to human in physiology, anatomy, nutrition and genetics, which provides an important animal model in the field of organ transplantation and human disease research. In this paper, the application of the gene edited animal models was summarized in the researches of 5 human diseases such as neurodegenerative diseases, familial hypertrophic cardiomyopathy, cancer, immunodeficiency diseases and metabolic diseases. We hope this paper will provide a reference for the research of human diseases and the preparation of relative animal models.