1
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Guan Z, Jiang Z. A systematic method for solving data imbalance in CRISPR off-target prediction tasks. Comput Biol Med 2024; 178:108781. [PMID: 38936075 DOI: 10.1016/j.compbiomed.2024.108781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 06/05/2024] [Accepted: 06/15/2024] [Indexed: 06/29/2024]
Abstract
Accurately identifying potential off-target sites in the CRISPR/Cas9 system is crucial for improving the efficiency and safety of editing. However, the imbalance of available off-target datasets has posed a major obstacle in enhancing prediction performance. Despite several prediction models have been developed to address this issue, there remains a lack of systematic research on handling data imbalance in off-target prediction. This article systematically investigates the data imbalance issue in off-target datasets and explores numerous methods to process data imbalance from a novel perspective. First, we highlight the impact of the imbalance problem on off-target prediction tasks by determining the imbalance ratios present in these datasets. Then, we provide a comprehensive review of various sampling techniques and cost-sensitive methods to mitigate class imbalance in off-target datasets. Finally, systematic experiments are conducted on several state-of-the-art prediction models to illustrate the impact of applying data imbalance solutions. The results show that class imbalance processing methods significantly improve the off-target prediction capabilities of the models across multiple testing datasets. The code and datasets used in this study are available at https://github.com/gzrgzx/CRISPR_Data_Imbalance.
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Affiliation(s)
- Zengrui Guan
- School of Computer Science and Technology, East China Normal University, Shanghai, 200062, China
| | - Zhenran Jiang
- School of Computer Science and Technology, East China Normal University, Shanghai, 200062, China.
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2
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Li JD, Taipale M, Blencowe BJ. Efficient, specific, and combinatorial control of endogenous exon splicing with dCasRx-RBM25. Mol Cell 2024; 84:2573-2589.e5. [PMID: 38917795 DOI: 10.1016/j.molcel.2024.05.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 04/24/2024] [Accepted: 05/30/2024] [Indexed: 06/27/2024]
Abstract
Efficient targeted control of splicing is a major goal of functional genomics and therapeutic applications. Guide (g)RNA-directed, deactivated (d)Cas CRISPR enzymes fused to splicing effectors represent a promising strategy due to the flexibility of these systems. However, efficient, specific, and generalizable activation of endogenous exons using this approach has not been previously reported. By screening over 300 dCasRx-splicing factor fusion proteins tethered to splicing reporters, we identify dCasRx-RBM25 as a potent activator of exons. Moreover, dCasRx-RBM25 efficiently activates the splicing of ∼90% of targeted endogenous alternative exons and displays high on-target specificity. Using gRNA arrays for combinatorial targeting, we demonstrate that dCasRx-RBM25 enables multiplexed activation and repression of exons. Using this feature, the targeting of neural-regulated exons in Ptpb1 and Puf60 in embryonic stem cells reveals combinatorial effects on downstream alternative splicing events controlled by these factors. Collectively, our results enable versatile, combinatorial exon-resolution functional assays and splicing-directed therapeutic applications.
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Affiliation(s)
- Jack Daiyang Li
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Mikko Taipale
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
| | - Benjamin J Blencowe
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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3
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Liu Y, Kong J, Liu G, Li Z, Xiao Y. Precise Gene Knock-In Tools with Minimized Risk of DSBs: A Trend for Gene Manipulation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2401797. [PMID: 38728624 PMCID: PMC11267366 DOI: 10.1002/advs.202401797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/29/2024] [Indexed: 05/12/2024]
Abstract
Gene knock-in refers to the insertion of exogenous functional genes into a target genome to achieve continuous expression. Currently, most knock-in tools are based on site-directed nucleases, which can induce double-strand breaks (DSBs) at the target, following which the designed donors carrying functional genes can be inserted via the endogenous gene repair pathway. The size of donor genes is limited by the characteristics of gene repair, and the DSBs induce risks like genotoxicity. New generation tools, such as prime editing, transposase, and integrase, can insert larger gene fragments while minimizing or eliminating the risk of DSBs, opening new avenues in the development of animal models and gene therapy. However, the elimination of off-target events and the production of delivery carriers with precise requirements remain challenging, restricting the application of the current knock-in treatments to mainly in vitro settings. Here, a comprehensive review of the knock-in tools that do not/minimally rely on DSBs and use other mechanisms is provided. Moreover, the challenges and recent advances of in vivo knock-in treatments in terms of the therapeutic process is discussed. Collectively, the new generation of DSBs-minimizing and large-fragment knock-in tools has revolutionized the field of gene editing, from basic research to clinical treatment.
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Affiliation(s)
- Yongfeng Liu
- Department of PharmacologySchool of PharmacyChina Pharmaceutical UniversityNanjing210009China
- State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjing210009China
- Mudi Meng Honors CollegeChina Pharmaceutical UniversityNanjing210009China
| | - Jianping Kong
- Department of PharmacologySchool of PharmacyChina Pharmaceutical UniversityNanjing210009China
- State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjing210009China
| | - Gongyu Liu
- Department of PharmacologySchool of PharmacyChina Pharmaceutical UniversityNanjing210009China
- State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjing210009China
| | - Zhaoxing Li
- Department of PharmacologySchool of PharmacyChina Pharmaceutical UniversityNanjing210009China
- State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjing210009China
- Chongqing Innovation Institute of China Pharmaceutical UniversityChongqing401135China
| | - Yibei Xiao
- Department of PharmacologySchool of PharmacyChina Pharmaceutical UniversityNanjing210009China
- State Key Laboratory of Natural MedicinesChina Pharmaceutical UniversityNanjing210009China
- Chongqing Innovation Institute of China Pharmaceutical UniversityChongqing401135China
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4
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Kim G, Kim HJ, Kim K, Kim HJ, Yang J, Seo SW. Tunable translation-level CRISPR interference by dCas13 and engineered gRNA in bacteria. Nat Commun 2024; 15:5319. [PMID: 38909033 PMCID: PMC11193725 DOI: 10.1038/s41467-024-49642-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 06/13/2024] [Indexed: 06/24/2024] Open
Abstract
Although CRISPR-dCas13, the RNA-guided RNA-binding protein, was recently exploited as a translation-level gene expression modulator, it has still been difficult to precisely control the level due to the lack of detailed characterization. Here, we develop a synthetic tunable translation-level CRISPR interference (Tl-CRISPRi) system based on the engineered guide RNAs that enable precise and predictable down-regulation of mRNA translation. First, we optimize the Tl-CRISPRi system for specific and multiplexed repression of genes at the translation level. We also show that the Tl-CRISPRi system is more suitable for independently regulating each gene in a polycistronic operon than the transcription-level CRISPRi (Tx-CRISPRi) system. We further engineer the handle structure of guide RNA for tunable and predictable repression of various genes in Escherichia coli and Vibrio natriegens. This tunable Tl-CRISPRi system is applied to increase the production of 3-hydroxypropionic acid (3-HP) by 14.2-fold via redirecting the metabolic flux, indicating the usefulness of this system for the flux optimization in the microbial cell factories based on the RNA-targeting machinery.
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Affiliation(s)
- Giho Kim
- School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea
| | - Ho Joon Kim
- School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea
| | - Keonwoo Kim
- School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea
| | - Hyeon Jin Kim
- Interdisciplinary Program in Bioengineering, Seoul National University, Seoul, South Korea
| | - Jina Yang
- Department of Chemical Engineering, Jeju National University, Jeju-si, South Korea
| | - Sang Woo Seo
- School of Chemical and Biological Engineering, Seoul National University, Seoul, Republic of Korea.
- Interdisciplinary Program in Bioengineering, Seoul National University, Seoul, South Korea.
- Institute of Chemical Processes, Seoul National University, Seoul, South Korea.
- Bio-MAX Institute, Seoul National University, Seoul, South Korea.
- Institute of Bio Engineering, Seoul National University, Seoul, South Korea.
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5
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Hwang H, Jeon H, Yeo N, Baek D. Big data and deep learning for RNA biology. Exp Mol Med 2024; 56:1293-1321. [PMID: 38871816 PMCID: PMC11263376 DOI: 10.1038/s12276-024-01243-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/27/2024] [Accepted: 03/05/2024] [Indexed: 06/15/2024] Open
Abstract
The exponential growth of big data in RNA biology (RB) has led to the development of deep learning (DL) models that have driven crucial discoveries. As constantly evidenced by DL studies in other fields, the successful implementation of DL in RB depends heavily on the effective utilization of large-scale datasets from public databases. In achieving this goal, data encoding methods, learning algorithms, and techniques that align well with biological domain knowledge have played pivotal roles. In this review, we provide guiding principles for applying these DL concepts to various problems in RB by demonstrating successful examples and associated methodologies. We also discuss the remaining challenges in developing DL models for RB and suggest strategies to overcome these challenges. Overall, this review aims to illuminate the compelling potential of DL for RB and ways to apply this powerful technology to investigate the intriguing biology of RNA more effectively.
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Affiliation(s)
- Hyeonseo Hwang
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyeonseong Jeon
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, Republic of Korea
- Genome4me Inc., Seoul, Republic of Korea
| | - Nagyeong Yeo
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Daehyun Baek
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea.
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, Republic of Korea.
- Genome4me Inc., Seoul, Republic of Korea.
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6
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Ciucci G, Braga L, Zacchigna S. Discovery platforms for RNA therapeutics. Br J Pharmacol 2024. [PMID: 38760893 DOI: 10.1111/bph.16424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 04/14/2024] [Accepted: 04/19/2024] [Indexed: 05/20/2024] Open
Abstract
RNA therapeutics are emerging as a unique opportunity to drug currently "undruggable" molecules and diseases. While their advantages over conventional, small molecule drugs, their therapeutic implications and the tools for their effective in vivo delivery have been extensively reviewed, little attention has been so far paid to the technological platforms exploited for the discovery of RNA therapeutics. Here, we provide an overview of the existing platforms and ex vivo assays for RNA discovery, their advantages and disadvantages, as well as their main fields of application, with specific focus on RNA therapies that have reached either phase 3 or market approval.
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Affiliation(s)
- Giulio Ciucci
- Cardiovascular Biology Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Luca Braga
- Functional Cell Biology Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Serena Zacchigna
- Cardiovascular Biology Laboratory, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
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7
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Nemudraia A, Nemudryi A, Wiedenheft B. Repair of CRISPR-guided RNA breaks enables site-specific RNA excision in human cells. Science 2024; 384:808-814. [PMID: 38662916 PMCID: PMC11175973 DOI: 10.1126/science.adk5518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 04/14/2024] [Indexed: 05/07/2024]
Abstract
Genome editing with CRISPR RNA-guided endonucleases generates DNA breaks that are resolved by cellular DNA repair machinery. However, analogous methods to manipulate RNA remain unavailable. We show that site-specific RNA breaks generated with type-III CRISPR complexes are repaired in human cells and that this repair can be used for programmable deletions in human transcripts to restore gene function. Collectively, this work establishes a technology for precise RNA manipulation with potential therapeutic applications.
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Affiliation(s)
- Anna Nemudraia
- Department of Microbiology and Cell Biology, Montana State University; Bozeman, MT, 59717, USA
| | - Artem Nemudryi
- Department of Microbiology and Cell Biology, Montana State University; Bozeman, MT, 59717, USA
| | - Blake Wiedenheft
- Department of Microbiology and Cell Biology, Montana State University; Bozeman, MT, 59717, USA
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8
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Hart SK, Wessels HH, Méndez-Mancilla A, Müller S, Drabavicius G, Choi O, Sanjana NE. Low copy CRISPR-Cas13d mitigates collateral RNA cleavage. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.594039. [PMID: 38798586 PMCID: PMC11118291 DOI: 10.1101/2024.05.13.594039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
While CRISPR-Cas13 systems excel in accurately targeting RNA, the potential for collateral RNA degradation poses a concern for therapeutic applications and limits broader adoption for transcriptome perturbations. We evaluate the extent to which collateral RNA cleavage occurs when Rfx Cas13d is delivered via plasmid transfection or lentiviral transduction and find that collateral activity only occurs with high levels of Rfx Cas13d expression. Using transcriptome-scale and combinatorial CRISPR pooled screens in cell lines with low-copy Rfx Cas13d, we find high on-target knockdown, without extensive collateral activity regardless of the expression level of the target gene. In contrast, transfection of Rfx Cas13d, which yields higher nuclease expression, results in collateral RNA degradation. Further, our analysis of a high-fidelity Cas13 variant uncovers a marked decrease in on-target efficiency, suggesting that its reduced collateral activity may be due to an overall diminished nuclease capability.
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9
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Fiflis DN, Rey NA, Venugopal-Lavanya H, Sewell B, Mitchell-Dick A, Clements KN, Milo S, Benkert AR, Rosales A, Fergione S, Asokan A. Repurposing CRISPR-Cas13 systems for robust mRNA trans-splicing. Nat Commun 2024; 15:2325. [PMID: 38485709 PMCID: PMC10940283 DOI: 10.1038/s41467-024-46172-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 02/16/2024] [Indexed: 03/18/2024] Open
Abstract
Type VI CRISPR enzymes have been developed as programmable RNA-guided Cas proteins for eukaryotic RNA editing. Notably, Cas13 has been utilized for site-targeted single base edits, demethylation, RNA cleavage or knockdown and alternative splicing. However, the ability to edit large stretches of mRNA transcripts remains a significant challenge. Here, we demonstrate that CRISPR-Cas13 systems can be repurposed to assist trans-splicing of exogenous RNA fragments into an endogenous pre-mRNA transcript, a method termed CRISPR Assisted mRNA Fragment Trans-splicing (CRAFT). Using split reporter-based assays, we evaluate orthogonal Cas13 systems, optimize guide RNA length and screen for optimal trans-splicing site(s) across a range of intronic targets. We achieve markedly improved editing of large 5' and 3' segments in different endogenous mRNAs across various mammalian cell types compared to other spliceosome-mediated trans-splicing methods. CRAFT can serve as a versatile platform for attachment of protein tags, studying the impact of multiple mutations/single nucleotide polymorphisms, modification of untranslated regions (UTRs) or replacing large segments of mRNA transcripts.
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Affiliation(s)
- David N Fiflis
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Nicolas A Rey
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | | | - Beatrice Sewell
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | | | - Katie N Clements
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Sydney Milo
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Abigail R Benkert
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Alan Rosales
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Sophia Fergione
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA
| | - Aravind Asokan
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
- Department of Surgery, Duke University School of Medicine, Durham, NC, USA.
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, USA.
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10
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Tieu V, Sotillo E, Bjelajac JR, Chen C, Malipatlolla M, Guerrero JA, Xu P, Quinn PJ, Fisher C, Klysz D, Mackall CL, Qi LS. A versatile CRISPR-Cas13d platform for multiplexed transcriptomic regulation and metabolic engineering in primary human T cells. Cell 2024; 187:1278-1295.e20. [PMID: 38387457 PMCID: PMC10965243 DOI: 10.1016/j.cell.2024.01.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 11/10/2023] [Accepted: 01/23/2024] [Indexed: 02/24/2024]
Abstract
CRISPR technologies have begun to revolutionize T cell therapies; however, conventional CRISPR-Cas9 genome-editing tools are limited in their safety, efficacy, and scope. To address these challenges, we developed multiplexed effector guide arrays (MEGA), a platform for programmable and scalable regulation of the T cell transcriptome using the RNA-guided, RNA-targeting activity of CRISPR-Cas13d. MEGA enables quantitative, reversible, and massively multiplexed gene knockdown in primary human T cells without targeting or cutting genomic DNA. Applying MEGA to a model of CAR T cell exhaustion, we robustly suppressed inhibitory receptor upregulation and uncovered paired regulators of T cell function through combinatorial CRISPR screening. We additionally implemented druggable regulation of MEGA to control CAR activation in a receptor-independent manner. Lastly, MEGA enabled multiplexed disruption of immunoregulatory metabolic pathways to enhance CAR T cell fitness and anti-tumor activity in vitro and in vivo. MEGA offers a versatile synthetic toolkit for applications in cancer immunotherapy and beyond.
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Affiliation(s)
- Victor Tieu
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elena Sotillo
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jeremy R Bjelajac
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Crystal Chen
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Meena Malipatlolla
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Justin A Guerrero
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peng Xu
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Patrick J Quinn
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chris Fisher
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dorota Klysz
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Crystal L Mackall
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Lei S Qi
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Sarafan ChEM-H, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, San Francisco, CA 94080, USA.
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11
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Pacesa M, Pelea O, Jinek M. Past, present, and future of CRISPR genome editing technologies. Cell 2024; 187:1076-1100. [PMID: 38428389 DOI: 10.1016/j.cell.2024.01.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 03/03/2024]
Abstract
Genome editing has been a transformative force in the life sciences and human medicine, offering unprecedented opportunities to dissect complex biological processes and treat the underlying causes of many genetic diseases. CRISPR-based technologies, with their remarkable efficiency and easy programmability, stand at the forefront of this revolution. In this Review, we discuss the current state of CRISPR gene editing technologies in both research and therapy, highlighting limitations that constrain them and the technological innovations that have been developed in recent years to address them. Additionally, we examine and summarize the current landscape of gene editing applications in the context of human health and therapeutics. Finally, we outline potential future developments that could shape gene editing technologies and their applications in the coming years.
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Affiliation(s)
- Martin Pacesa
- Laboratory of Protein Design and Immunoengineering, École Polytechnique Fédérale de Lausanne and Swiss Institute of Bioinformatics, Station 19, CH-1015 Lausanne, Switzerland
| | - Oana Pelea
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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12
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Morris JA, Sun JS, Sanjana NE. Next-generation forward genetic screens: uniting high-throughput perturbations with single-cell analysis. Trends Genet 2024; 40:118-133. [PMID: 37989654 PMCID: PMC10872607 DOI: 10.1016/j.tig.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/23/2023]
Abstract
Programmable genome-engineering technologies, such as CRISPR (clustered regularly interspaced short palindromic repeats) nucleases and massively parallel CRISPR screens that capitalize on this programmability, have transformed biomedical science. These screens connect genes and noncoding genome elements to disease-relevant phenotypes, but until recently have been limited to individual phenotypes such as growth or fluorescent reporters of gene expression. By pairing massively parallel screens with high-dimensional profiling of single-cell types/states, we can now measure how individual genetic perturbations or combinations of perturbations impact the cellular transcriptome, proteome, and epigenome. We review technologies that pair CRISPR screens with single-cell multiomics and the unique opportunities afforded by extending pooled screens using deep multimodal phenotyping.
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Affiliation(s)
- John A Morris
- New York Genome Center, New York, NY 10013, USA; Department of Biology, New York University, New York, NY 10003, USA
| | - Jennifer S Sun
- New York Genome Center, New York, NY 10013, USA; Department of Biology, New York University, New York, NY 10003, USA
| | - Neville E Sanjana
- New York Genome Center, New York, NY 10013, USA; Department of Biology, New York University, New York, NY 10003, USA.
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13
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Bailleux C, Gal J, Chamorey E, Mograbi B, Milano G. Artificial Intelligence and Anticancer Drug Development-Keep a Cool Head. Pharmaceutics 2024; 16:211. [PMID: 38399265 PMCID: PMC10893490 DOI: 10.3390/pharmaceutics16020211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Artificial intelligence (AI) is progressively spreading through the world of health, particularly in the field of oncology. AI offers new, exciting perspectives in drug development as toxicity and efficacy can be predicted from computer-designed active molecular structures. AI-based in silico clinical trials are still at their inception in oncology but their wider use is eagerly awaited as they should markedly reduce durations and costs. Health authorities cannot neglect this new paradigm in drug development and should take the requisite measures to include AI as a new pillar in conducting clinical research in oncology.
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Affiliation(s)
- Caroline Bailleux
- Centre Antoine Lacassagne, Oncology Departement Unit, University Côte d’Azur, 06000 Nice, France;
| | - Jocelyn Gal
- Centre Antoine Lacassagne, Epidemiology and Biostatistics Department, University Côte d’Azur, 06000 Nice, France; (J.G.); (E.C.)
| | - Emmanuel Chamorey
- Centre Antoine Lacassagne, Epidemiology and Biostatistics Department, University Côte d’Azur, 06000 Nice, France; (J.G.); (E.C.)
| | | | - Gérard Milano
- Centre Antoine Lacassagne, University Côte d’Azur, 33 Avenue de Valombrose, 06189 Nice, France
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14
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Molina Vargas A, Sinha S, Osborn R, Arantes P, Patel A, Dewhurst S, Hardy D, Cameron A, Palermo G, O’Connell M. New design strategies for ultra-specific CRISPR-Cas13a-based RNA detection with single-nucleotide mismatch sensitivity. Nucleic Acids Res 2024; 52:921-939. [PMID: 38033324 PMCID: PMC10810210 DOI: 10.1093/nar/gkad1132] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/27/2023] [Accepted: 11/09/2023] [Indexed: 12/02/2023] Open
Abstract
An increasingly pressing need for clinical diagnostics has required the development of novel nucleic acid-based detection technologies that are sensitive, fast, and inexpensive, and that can be deployed at point-of-care. Recently, the RNA-guided ribonuclease CRISPR-Cas13 has been successfully harnessed for such purposes. However, developing assays for detection of genetic variability, for example single-nucleotide polymorphisms, is still challenging and previously described design strategies are not always generalizable. Here, we expanded our characterization of LbuCas13a RNA-detection specificity by performing a combination of experimental RNA mismatch tolerance profiling, molecular dynamics simulations, protein, and crRNA engineering. We found certain positions in the crRNA-target-RNA duplex that are particularly sensitive to mismatches and establish the effect of RNA concentration in mismatch tolerance. Additionally, we determined that shortening the crRNA spacer or modifying the direct repeat of the crRNA leads to stricter specificities. Furthermore, we harnessed our understanding of LbuCas13a allosteric activation pathways through molecular dynamics and structure-guided engineering to develop novel Cas13a variants that display increased sensitivities to single-nucleotide mismatches. We deployed these Cas13a variants and crRNA design strategies to achieve superior discrimination of SARS-CoV-2 strains compared to wild-type LbuCas13a. Together, our work provides new design criteria and Cas13a variants to use in future easier-to-implement Cas13-based RNA detection applications.
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Affiliation(s)
- Adrian M Molina Vargas
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Department of Biomedical Genetics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Souvik Sinha
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Raven Osborn
- Clinical and Translational Sciences Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Pablo R Arantes
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Amun Patel
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
| | - Stephen Dewhurst
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Dwight J Hardy
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Andrew Cameron
- Department of Pathology and Laboratory Medicine, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Giulia Palermo
- Department of Bioengineering, University of California Riverside, Riverside, CA, USA
- Department of Chemistry, University of California Riverside, Riverside, CA, USA
| | - Mitchell R O’Connell
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
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15
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Kuo HC, Prupes J, Chou CW, Finkelstein IJ. Massively parallel profiling of RNA-targeting CRISPR-Cas13d. Nat Commun 2024; 15:498. [PMID: 38216559 PMCID: PMC10786891 DOI: 10.1038/s41467-024-44738-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 01/02/2024] [Indexed: 01/14/2024] Open
Abstract
CRISPR-Cas13d cleaves RNA and is used in vivo and for diagnostics. However, a systematic understanding of its RNA binding and cleavage specificity is lacking. Here, we describe an RNA Chip-Hybridized Association-Mapping Platform (RNA-CHAMP) for measuring the binding affinity for > 10,000 RNAs containing structural perturbations and other alterations relative to the CRISPR RNA (crRNA). Deep profiling of Cas13d reveals that it does not require a protospacer flanking sequence but is exquisitely sensitive to secondary structure within the target RNA. Cas13d binding is penalized by mismatches in the distal crRNA-target RNA region, while alterations in the proximal region inhibit nuclease activity. A biophysical model built from these data reveals that target recognition initiates in the distal end of the target RNA. Using this model, we design crRNAs that can differentiate between SARS-CoV-2 variants by modulating nuclease activation. This work describes the key determinants of RNA targeting by a type VI CRISPR enzyme.
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Affiliation(s)
- Hung-Che Kuo
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.
| | - Joshua Prupes
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Chia-Wei Chou
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.
- Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX, 78712, USA.
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16
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Dixit S, Kumar A, Srinivasan K, Vincent PMDR, Ramu Krishnan N. Advancing genome editing with artificial intelligence: opportunities, challenges, and future directions. Front Bioeng Biotechnol 2024; 11:1335901. [PMID: 38260726 PMCID: PMC10800897 DOI: 10.3389/fbioe.2023.1335901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 12/19/2023] [Indexed: 01/24/2024] Open
Abstract
Clustered regularly interspaced short palindromic repeat (CRISPR)-based genome editing (GED) technologies have unlocked exciting possibilities for understanding genes and improving medical treatments. On the other hand, Artificial intelligence (AI) helps genome editing achieve more precision, efficiency, and affordability in tackling various diseases, like Sickle cell anemia or Thalassemia. AI models have been in use for designing guide RNAs (gRNAs) for CRISPR-Cas systems. Tools like DeepCRISPR, CRISTA, and DeepHF have the capability to predict optimal guide RNAs (gRNAs) for a specified target sequence. These predictions take into account multiple factors, including genomic context, Cas protein type, desired mutation type, on-target/off-target scores, potential off-target sites, and the potential impacts of genome editing on gene function and cell phenotype. These models aid in optimizing different genome editing technologies, such as base, prime, and epigenome editing, which are advanced techniques to introduce precise and programmable changes to DNA sequences without relying on the homology-directed repair pathway or donor DNA templates. Furthermore, AI, in collaboration with genome editing and precision medicine, enables personalized treatments based on genetic profiles. AI analyzes patients' genomic data to identify mutations, variations, and biomarkers associated with different diseases like Cancer, Diabetes, Alzheimer's, etc. However, several challenges persist, including high costs, off-target editing, suitable delivery methods for CRISPR cargoes, improving editing efficiency, and ensuring safety in clinical applications. This review explores AI's contribution to improving CRISPR-based genome editing technologies and addresses existing challenges. It also discusses potential areas for future research in AI-driven CRISPR-based genome editing technologies. The integration of AI and genome editing opens up new possibilities for genetics, biomedicine, and healthcare, with significant implications for human health.
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Affiliation(s)
- Shriniket Dixit
- School of Computer Science and Engineering, Vellore Institute of Technology, Vellore, India
| | - Anant Kumar
- School of Bioscience and Technology, Vellore Institute of Technology, Vellore, India
| | - Kathiravan Srinivasan
- School of Computer Science and Engineering, Vellore Institute of Technology, Vellore, India
| | - P. M. Durai Raj Vincent
- School of Computer Science Engineering and Information Systems, Vellore Institute of Technology, Vellore, India
| | - Nadesh Ramu Krishnan
- School of Computer Science Engineering and Information Systems, Vellore Institute of Technology, Vellore, India
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17
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Shi P, Wu X. Programmable RNA targeting with CRISPR-Cas13. RNA Biol 2024; 21:1-9. [PMID: 38764173 PMCID: PMC11110701 DOI: 10.1080/15476286.2024.2351657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2024] [Indexed: 05/21/2024] Open
Abstract
The RNA-targeting CRISPR-Cas13 system has enabled precise engineering of endogenous RNAs, significantly advancing our understanding of RNA regulation and the development of RNA-based diagnostic and therapeutic applications. This review aims to provide a summary of Cas13-based RNA targeting tools and applications, discuss limitations and challenges of existing tools and suggest potential directions for further development of the RNA targeting system.
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Affiliation(s)
- Peiguo Shi
- Department of Medicine and Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Xuebing Wu
- Department of Medicine and Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
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18
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Wei J, Lotfy P, Faizi K, Baungaard S, Gibson E, Wang E, Slabodkin H, Kinnaman E, Chandrasekaran S, Kitano H, Durrant MG, Duffy CV, Pawluk A, Hsu PD, Konermann S. Deep learning and CRISPR-Cas13d ortholog discovery for optimized RNA targeting. Cell Syst 2023; 14:1087-1102.e13. [PMID: 38091991 DOI: 10.1016/j.cels.2023.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 05/03/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023]
Abstract
Effective and precise mammalian transcriptome engineering technologies are needed to accelerate biological discovery and RNA therapeutics. Despite the promise of programmable CRISPR-Cas13 ribonucleases, their utility has been hampered by an incomplete understanding of guide RNA design rules and cellular toxicity resulting from off-target or collateral RNA cleavage. Here, we quantified the performance of over 127,000 RfxCas13d (CasRx) guide RNAs and systematically evaluated seven machine learning models to build a guide efficiency prediction algorithm orthogonally validated across multiple human cell types. Deep learning model interpretation revealed preferred sequence motifs and secondary features for highly efficient guides. We next identified and screened 46 novel Cas13d orthologs, finding that DjCas13d achieves low cellular toxicity and high specificity-even when targeting abundant transcripts in sensitive cell types, including stem cells and neurons. Our Cas13d guide efficiency model was successfully generalized to DjCas13d, illustrating the power of combining machine learning with ortholog discovery to advance RNA targeting in human cells.
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Affiliation(s)
- Jingyi Wei
- Department of Bioengineering, Stanford University, Stanford, CA, USA; Department of Biochemistry, Stanford University, Stanford, CA, USA; Arc Institute, Palo Alto, CA, USA
| | - Peter Lotfy
- Laboratory of Molecular and Cell Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Kian Faizi
- Laboratory of Molecular and Cell Biology, Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | | | - Eleanor Wang
- Laboratory of Molecular and Cell Biology, Salk Institute for Biological Studies, La Jolla, CA, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Hannah Slabodkin
- Department of Biochemistry, Stanford University, Stanford, CA, USA; Arc Institute, Palo Alto, CA, USA
| | - Emily Kinnaman
- Department of Biochemistry, Stanford University, Stanford, CA, USA; Arc Institute, Palo Alto, CA, USA
| | - Sita Chandrasekaran
- Arc Institute, Palo Alto, CA, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Hugo Kitano
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Matthew G Durrant
- Arc Institute, Palo Alto, CA, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Connor V Duffy
- Arc Institute, Palo Alto, CA, USA; Department of Genetics, Stanford University, Stanford, CA, USA
| | | | - Patrick D Hsu
- Arc Institute, Palo Alto, CA, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA; Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA.
| | - Silvana Konermann
- Department of Biochemistry, Stanford University, Stanford, CA, USA; Arc Institute, Palo Alto, CA, USA.
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19
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Wen DJ, Theodoris CV. Interpretable model of CRISPR-Cas9 enzymatic reactions. NATURE COMPUTATIONAL SCIENCE 2023; 3:1011-1012. [PMID: 38177728 DOI: 10.1038/s43588-023-00570-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Affiliation(s)
- David J Wen
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Program in Developmental and Stem Cell Biology (DSCB), University of California, San Francisco (UCSF), San Francisco, CA, USA
| | - Christina V Theodoris
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA.
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA.
- Department of Pediatrics, UCSF, San Francisco, CA, USA.
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20
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Song B, Liu D, Dai W, McMyn N, Wang Q, Yang D, Krejci A, Vasilyev A, Untermoser N, Loregger A, Song D, Williams B, Rosen B, Cheng X, Chao L, Kale HT, Zhang H, Diao Y, Bürckstümmer T, Siliciano JM, Li JJ, Siliciano R, Huangfu D, Li W. Decoding Heterogenous Single-cell Perturbation Responses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.30.564796. [PMID: 37961332 PMCID: PMC10635009 DOI: 10.1101/2023.10.30.564796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Understanding diverse responses of individual cells to the same perturbation is central to many biological and biomedical problems. Current methods, however, do not precisely quantify the strength of perturbation responses and, more importantly, reveal new biological insights from heterogeneity in responses. Here we introduce the perturbation-response score (PS), based on constrained quadratic optimization, to quantify diverse perturbation responses at a single-cell level. Applied to single-cell transcriptomes of large-scale genetic perturbation datasets (e.g., Perturb-seq), PS outperforms existing methods for quantifying partial gene perturbation responses. In addition, PS presents two major advances. First, PS enables large-scale, single-cell-resolution dosage analysis of perturbation, without the need to titrate perturbation strength. By analyzing the dose-response patterns of over 2,000 essential genes in Perturb-seq, we identify two distinct patterns, depending on whether a moderate reduction in their expression induces strong downstream expression alterations. Second, PS identifies intrinsic and extrinsic biological determinants of perturbation responses. We demonstrate the application of PS in contexts such as T cell stimulation, latent HIV-1 expression, and pancreatic cell differentiation. Notably, PS unveiled a previously unrecognized, cell-type-specific role of coiled-coil domain containing 6 (CCDC6) in guiding liver and pancreatic lineage decisions, where CCDC6 knockouts drive the endoderm cell differentiation towards liver lineage, rather than pancreatic lineage. The PS approach provides an innovative method for dose-to-function analysis and will enable new biological discoveries from single-cell perturbation datasets. One sentence summary We present a method to quantify diverse perturbation responses and discover novel biological insights in single-cell perturbation datasets.
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21
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Kimchi O, Larsen BB, Dunkley ORS, te Velthuis AJ, Myhrvold C. RNA structure modulates Cas13 activity and enables mismatch detection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.05.560533. [PMID: 37987004 PMCID: PMC10659300 DOI: 10.1101/2023.10.05.560533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The RNA-targeting CRISPR nuclease Cas13 has emerged as a powerful tool for applications ranging from nucleic acid detection to transcriptome engineering and RNA imaging1-6. Cas13 is activated by the hybridization of a CRISPR RNA (crRNA) to a complementary single-stranded RNA (ssRNA) protospacer in a target RNA1,7. Though Cas13 is not activated by double-stranded RNA (dsRNA) in vitro, it paradoxically demonstrates robust RNA targeting in environments where the vast majority of RNAs are highly structured2,8. Understanding Cas13's mechanism of binding and activation will be key to improving its ability to detect and perturb RNA; however, the mechanism by which Cas13 binds structured RNAs remains unknown9. Here, we systematically probe the mechanism of LwaCas13a activation in response to RNA structure perturbations using a massively multiplexed screen. We find that there are two distinct sequence-independent modes by which secondary structure affects Cas13 activity: structure in the protospacer region competes with the crRNA and can be disrupted via a strand-displacement mechanism, while structure in the region 3' to the protospacer has an allosteric inhibitory effect. We leverage the kinetic nature of the strand displacement process to improve Cas13-based RNA detection, enhancing mismatch discrimination by up to 50-fold and enabling sequence-agnostic mutation identification at low (<1%) allele frequencies. Our work sets a new standard for CRISPR-based nucleic acid detection and will enable intelligent and secondary-structure-guided target selection while also expanding the range of RNAs available for targeting with Cas13.
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Affiliation(s)
- Ofer Kimchi
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, 08544, USA
| | - Benjamin B. Larsen
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544, USA
| | - Owen R. S. Dunkley
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544, USA
| | | | - Cameron Myhrvold
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, 08544, USA
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, 08544, USA
- Omenn-Darling Bioengineering Institute, Princeton University, Princeton, New Jersey, 08544, USA
- Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA
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22
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Schertzer MD, Stirn A, Isaev K, Pereira L, Das A, Harbison C, Park SH, Wessels HH, Sanjana NE, Knowles DA. Cas13d-mediated isoform-specific RNA knockdown with a unified computational and experimental toolbox. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557474. [PMID: 37745416 PMCID: PMC10515814 DOI: 10.1101/2023.09.12.557474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Alternative splicing is an essential mechanism for diversifying proteins, in which mature RNA isoforms produce proteins with potentially distinct functions. Two major challenges in characterizing the cellular function of isoforms are the lack of experimental methods to specifically and efficiently modulate isoform expression and computational tools for complex experimental design. To address these gaps, we developed and methodically tested a strategy which pairs the RNA-targeting CRISPR/Cas13d system with guide RNAs that span exon-exon junctions in the mature RNA. We performed a high-throughput essentiality screen, quantitative RT-PCR assays, and PacBio long read sequencing to affirm our ability to specifically target and robustly knockdown individual RNA isoforms. In parallel, we provide computational tools for experimental design and screen analysis. Considering all possible splice junctions annotated in GENCODE for multi-isoform genes and our gRNA efficacy predictions, we estimate that our junction-centric strategy can uniquely target up to 89% of human RNA isoforms, including 50,066 protein-coding and 11,415 lncRNA isoforms. Importantly, this specificity spans all splicing and transcriptional events, including exon skipping and inclusion, alternative 5' and 3' splice sites, and alternative starts and ends.
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Affiliation(s)
- Megan D Schertzer
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
| | - Andrew Stirn
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
| | - Keren Isaev
- New York Genome Center, New York, NY
- Department of Systems Biology, Columbia University, New York, NY
| | | | - Anjali Das
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
| | | | - Stella H Park
- New York Genome Center, New York, NY
- Department of Biomedical Engineering, Columbia University, New York, NY
| | - Hans-Hermann Wessels
- New York Genome Center, New York, NY
- Department of Biology, New York University, New York, NY
| | - Neville E Sanjana
- New York Genome Center, New York, NY
- Department of Biology, New York University, New York, NY
| | - David A Knowles
- New York Genome Center, New York, NY
- Department of Computer Science, Columbia University, New York, NY
- Department of Systems Biology, Columbia University, New York, NY
- Data Science Institute, Columbia University, New York, NY
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23
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Nemudraia A, Nemudryi A, Wiedenheft B. Repair of CRISPR-guided RNA breaks enables site-specific RNA editing in human cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.29.555404. [PMID: 37693568 PMCID: PMC10491232 DOI: 10.1101/2023.08.29.555404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Genome editing with CRISPR RNA-guided endonucleases generates DNA breaks that are resolved by cellular DNA repair machinery. However, analogous methods to manipulate RNA remain unavailable. Here, we show that site-specific RNA breaks generated with RNA-targeting CRISPR complexes are repaired in human cells, and this repair can be used for programmable deletions in human transcripts that restore gene function. Collectively, this work establishes a technology for precise RNA manipulation with potential therapeutic applications.
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Affiliation(s)
- Anna Nemudraia
- Department of Microbiology and Cell Biology, Montana State University; Bozeman, MT, 59717, USA
| | - Artem Nemudryi
- Department of Microbiology and Cell Biology, Montana State University; Bozeman, MT, 59717, USA
| | - Blake Wiedenheft
- Department of Microbiology and Cell Biology, Montana State University; Bozeman, MT, 59717, USA
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24
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Vargas AMM, Osborn R, Sinha S, Arantes PR, Patel A, Dewhurst S, Palermo G, O'Connell MR. New design strategies for ultra-specific CRISPR-Cas13a-based RNA-diagnostic tools with single-nucleotide mismatch sensitivity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.26.550755. [PMID: 37547020 PMCID: PMC10402140 DOI: 10.1101/2023.07.26.550755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
The pressing need for clinical diagnostics has required the development of novel nucleic acid-based detection technologies that are sensitive, fast, and inexpensive, and that can be deployed at point-of-care. Recently, the RNA-guided ribonuclease CRISPR-Cas13 has been successfully harnessed for such purposes. However, developing assays for detection of genetic variability, for example single-nucleotide polymorphisms, is still challenging and previously described design strategies are not always generalizable. Here, we expanded our characterization of LbuCas13a RNA-detection specificity by performing a combination of experimental RNA mismatch tolerance profiling, molecular dynamics simulations, protein, and crRNA engineering. We found certain positions in the crRNA-target-RNA duplex that are particularly sensitive to mismatches and establish the effect of RNA concentration in mismatch tolerance. Additionally, we determined that shortening the crRNA spacer or modifying the direct repeat of the crRNA leads to stricter specificities. Furthermore, we harnessed our understanding of LbuCas13a allosteric activation pathways through molecular dynamics and structure-guided engineering to develop novel Cas13a variants that display increased sensitivities to single-nucleotide mismatches. We deployed these Cas13a variants and crRNA design strategies to achieve superior discrimination of SARS-CoV-2 strains compared to wild-type LbuCas13a. Together, our work provides new design criteria and new Cas13a variants for easier-to-implement Cas13-based diagnostics. KEY POINTS Certain positions in the Cas13a crRNA-target-RNA duplex are particularly sensitive to mismatches.Understanding Cas13a's allosteric activation pathway allowed us to develop novel high-fidelity Cas13a variants.These Cas13a variants and crRNA design strategies achieve superior discrimination of SARS-CoV-2 strains. GRAPHICAL ABSTRACT
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