Key elements for designing and performing a CRISPR/Cas9-based genetic screen

CAR-T cell therapy: a game-changer in cancer treatment and beyond

In recent years, cancer has become one of the primary causes of mortality, approximately 10 million deaths worldwide each year. The most advanced, chimeric antigen receptor (CAR) T cell immunotherapy has turned out as a promising treatment for cancer. CAR-T cell therapy involves the genetic modification of T cells obtained from the patient's blood, and infusion back to the patients. CAR-T cell immunotherapy has led to a significant improvement in the remission rates of hematological cancers. CAR-T cell therapy presently limited to hematological cancers, there are ongoing efforts to develop additional CAR constructs such as bispecific CAR, tandem CAR, inhibitory CAR, combined antigens, CRISPR gene-editing, and nanoparticle delivery. With these advancements, CAR-T cell therapy holds promise concerning potential to improve upon traditional cancer treatments such as chemotherapy and radiation while reducing associated toxicities. This review covers recent advances and advantages of CAR-T cell immunotherapy.

A Recombinant Turkey Herpesvirus Expressing the F Protein of Newcastle Disease Virus Genotype XII Generated by NHEJ-CRISPR/Cas9 and Cre-LoxP Systems Confers Protection against Genotype XII Challenge in Chickens

In this study, we developed a new recombinant virus rHVT-F using a Turkey herpesvirus (HVT) vector, expressing the fusion (F) protein of the genotype XII Newcastle disease virus (NDV) circulating in Peru. We evaluated the viral shedding and efficacy against the NDV genotype XII challenge in specific pathogen-free (SPF) chickens. The F protein expression cassette was inserted in the unique long (UL) UL45–UL46 intergenic locus of the HVT genome by utilizing a clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 gene-editing technology via a non-homologous end joining (NHEJ) repair pathway. The rHVT-F virus, which expressed the F protein stably in vitro and in vivo, showed similar growth kinetics to the wild-type HVT (wtHVT) virus. The F protein expression of the rHVT-F virus was detected by an indirect immunofluorescence assay (IFA), Western blotting, and a flow cytometry assay. The presence of an NDV-specific IgY antibody was detected in serum samples by an enzyme-linked immunosorbent assay (ELISA) in SPF chickens vaccinated with the rHVT-F virus. In the challenge experiment, the rHVT-F vaccine fully protects a high, and significantly reduced, virus shedding in oral at 5 days post-challenge (dpc). In conclusion, this new rHVT-F vaccine candidate is capable of fully protecting SPF chickens against the genotype XII challenge.

CRISPR-Cas9-Mediated Gene Silencing in Cultured Human Epithelia

CRISPR/Cas9 technology enables rapid and efficient genome editing in a variety of experimental systems. Genome editing using CRISPR/Cas9 has become an increasingly popular genetic engineering tool due to (1) an extensive array of commercial ready-to-use CRIPSR/Cas9 systems, (2) improved efficiency of cell delivery, and (3) the possibility to do multigene editing. Here, we describe a method to introduce single gene disruption in lung bronchial epithelial cells. This approach can be used to study host factors important for pathogen interaction or to identify and study genetic markers determining susceptibility to fungal disease.

Modeling neurodegenerative diseases with cerebral organoids and other three-dimensional culture systems: focus on Alzheimer's disease

Many neurodegenerative diseases (NDs) such as Alzheimer’s disease, Parkinson’s disease, frontotemporal dementia, amyotrophic lateral sclerosis and Huntington’s disease, are characterized by the progressive accumulation of abnormal proteinaceous assemblies in specific cell types and regions of the brain, leading to cellular dysfunction and brain damage. Although animal- and in vitro-based studies of NDs have provided the field with an extensive understanding of some of the mechanisms underlying these diseases, findings from these studies have not yielded substantial progress in identifying treatment options for patient populations. This necessitates the development of complementary model systems that are better suited to recapitulate human-specific features of ND pathogenesis. Three-dimensional (3D) culture systems, such as cerebral organoids generated from human induced pluripotent stem cells, hold significant potential to model NDs in a complex, tissue-like environment. In this review, we discuss the advantages of 3D culture systems and 3D modeling of NDs, especially AD and FTD. We also provide an overview of the challenges and limitations of the current 3D culture systems. Finally, we propose a few potential future directions in applying state-of-the-art technologies in 3D culture systems to understand the mechanisms of NDs and to accelerate drug discovery.

In silico Method in CRISPR/Cas System: An Expedite and Powerful Booster

The CRISPR/Cas system has stood in the center of attention in the last few years as a revolutionary gene editing tool with a wide application to investigate gene functions. However, the labor-intensive workflow requires a sophisticated pre-experimental and post-experimental analysis, thus becoming one of the hindrances for the further popularization of practical applications. Recently, the increasing emergence and advancement of the in silico methods play a formidable role to support and boost experimental work. However, various tools based on distinctive design principles and frameworks harbor unique characteristics that are likely to confuse users about how to choose the most appropriate one for their purpose. In this review, we will present a comprehensive overview and comparisons on the in silico methods from the aspects of CRISPR/Cas system identification, guide RNA design, and post-experimental assistance. Furthermore, we establish the hypotheses in light of the new trends around the technical optimization and hope to provide significant clues for future tools development.

CRISPR Tools for Physiology and Cell State Changes: Potential of Transcriptional Engineering and Epigenome Editing

Given the large amount of genome-wide data that have been collected during the last decades, a good understanding of how and why cells change during development, homeostasis, and disease might be expected. Unfortunately, the opposite is true; triggers that cause cellular state changes remain elusive, and the underlying molecular mechanisms are poorly understood. Although genes with the potential to influence cell states are known, the historic dependency on methods that manipulate gene expression outside the endogenous chromatin context has prevented us from understanding how cells organize, interpret, and protect cellular programs. Fortunately, recent methodological innovations are now providing options to answer these outstanding questions, by allowing to target and manipulate individual genomic and epigenomic loci. In particular, three experimental approaches are now feasible due to DNA targeting tools, namely, activation and/or repression of master transcription factors in their endogenous chromatin context; targeting transcription factors to endogenous, alternative, or inaccessible sites; and finally, functional manipulation of the chromatin context. In this article, we discuss the molecular basis of DNA targeting tools and review the potential of these new technologies before we summarize how these have already been used for the manipulation of cellular states and hypothesize about future applications.

CRISPR/Cas9-Based Genetic Screening to Study T-Cell Function

T-cell-based cancer immunotherapies have emerged as a promising approach for cancer treatment, highlighting the importance of understanding the regulation of T-cell function. However, the molecular mechanisms underlying T-cell activation are not fully understood. The CRISPR/Cas9 system can serve as a robust method to systematically study signaling pathways. In this chapter, we describe details of using the CRISPR screen to identify regulators in TCR signaling, from the sgRNA library construction to genomic DNA sequencing. We also add some notes to further help readers performing the CRISPR screen. This approach can be readily adapted to study the activation of other immune cells, including B cells and dendritic cells.

NGS-Based High-Throughput Screen to Identify MicroRNAs Regulating Growth of B-Cell Lymphoma

MicroRNAs (miRNAs) play important roles in development, differentiation, and homeostasis by regulating protein translation. In B-cell lymphoma, many miRNAs have altered expression levels, and for a limited subset of them, experimental data supports their functional relevance in lymphoma pathogenesis. This chapter describes an unbiased next-generation sequencing (NGS)-based high-throughput screening approach to identify miRNAs that are involved in the control of cell growth. First, we provide a protocol for performing high-throughput screening for miRNA inhibition and overexpression. Second, we describe the procedure for next-generation sequencing library preparation. Third, we provide a workflow for data analysis.

Genome-Editing Technologies: Concept, Pros, and Cons of Various Genome-Editing Techniques and Bioethical Concerns for Clinical Application

The traditional healthcare system is at the doorstep for entering into the arena of molecular medicine. The enormous knowledge and ongoing research have now been able to demonstrate methodologies that can alter DNA coding. The techniques used to edit or change the genome evolved from the earlier attempts like nuclease technologies, homing endonucleases, and certain chemical methods. Molecular techniques like meganuclease, transcription activator-like effector nucleases (TALENs), and zinc-finger nucleases (ZFNs) initially emerged as genome-editing technologies. These initial technologies suffer from lower specificity due to their off-targets side effects. Moreover, from biotechnology's perspective, the main obstacle was to develop simple but effective delivery methods for host cell entry. Later, small RNAs, including microRNA (miRNA) and small interfering RNA (siRNA), have been widely adopted in the research laboratories to replace lab animals and cell lines. The latest discovery of CRISPR/Cas9 technology seems more encouraging by providing better efficiency, feasibility, and multi-role clinical application. This later biotechnology seem to take genome-engineering techniques to the next level of molecular engineering. This review generally discusses the various gene-editing technologies in terms of the mechanisms of action, advantages, and side effects.

Methods for genetic analysis of mammalian ER-associated degradation

Identification and degradation of misfolded proteins by the ubiquitin-proteasome system (UPS) is crucial for maintaining proteostasis, but only a handful of UPS components have been linked to the recognition of specific substrates. Studies in Saccharomyces cerevisiae using systematic perturbation of nonessential genes have uncovered UPS components that recognize and ubiquitylate model substrates of the UPS; however, similar analyses in metazoans have been limited. In this chapter, we describe methods for using CRISPR/Cas9 technology combined with genome-wide high complexity single guide (sgRNA) libraries and a transcriptional shutoff strategy for phenotypic selection based on kinetic measurements of protein turnover to identify the genes required to degrade model clients of the mammalian ER-associated degradation system. We also discuss considerations for screen design, execution, and interpretation.

CRISPR Ethics: Moral Considerations for Applications of a Powerful Tool

With the emergence of CRISPR technology, targeted editing of a wide variety of genomes is no longer an abstract hypothetical, but occurs regularly. As application areas of CRISPR are exceeding beyond research and biomedical therapies, new and existing ethical concerns abound throughout the global community about the appropriate scope of the systems' use. Here we review fundamental ethical issues including the following: 1) the extent to which CRISPR use should be permitted; 2) access to CRISPR applications; 3) whether a regulatory framework(s) for clinical research involving human subjects might accommodate all types of human genome editing, including editing of the germline; and 4) whether international regulations governing inappropriate CRISPR utilization should be crafted and publicized. We conclude that moral decision making should evolve as the science of genomic engineering advances and hold that it would be reasonable for national and supranational legislatures to consider evidence-based regulation of certain CRISPR applications for the betterment of human health and progress.

Genome-wide CRISPR screen identifies FAM49B as a key regulator of actin dynamics and T cell activation

Despite decades of research, mechanisms controlling T cell activation remain only partially understood, which hampers T cell-based immune cancer therapies. Here, we performed a genome-wide CRISPR screen to search for genes that regulate T cell activation. Our screen confirmed many of the known regulators in proximal T cell receptor signaling and, importantly, also uncovered a previously uncharacterized regulator, FAM49B (family with sequence similarity 49 member B). FAM49B deficiency led to hyperactivation of Jurkat T cells following T cell receptor stimulation, as indicated by enhancement of CD69 induction, PAK phosphorylation, and actin assembly. FAM49B directly interacted with the active form of the small GTPase Rac, and genetic disruption of the FAM49B-Rac interaction compromised FAM49B function. Thus, FAM49B inhibits T cell activation by repressing Rac activity and modulating cytoskeleton reorganization.