CRISPR-Cas System: The Current and Emerging Translational Landscape

Abstract

CRISPR-Cas technology has rapidly changed life science research and human medicine. The ability to add, remove, or edit human DNA sequences has transformative potential for treating congenital and acquired human diseases. The timely maturation of the cell and gene therapy ecosystem and its seamless integration with CRISPR-Cas technologies has enabled the development of therapies that could potentially cure not only monogenic diseases such as sickle cell anemia and muscular dystrophy, but also complex heterogenous diseases such as cancer and diabetes. Here, we review the current landscape of clinical trials involving the use of various CRISPR-Cas systems as therapeutics for human diseases, discuss challenges, and explore new CRISPR-Cas-based tools such as base editing, prime editing, CRISPR-based transcriptional regulation, CRISPR-based epigenome editing, and RNA editing, each promising new functionality and broadening therapeutic potential. Finally, we discuss how the CRISPR-Cas system is being used to understand the biology of human diseases through the generation of large animal disease models used for preclinical testing of emerging therapeutics.

Keywords: CRISPR animal models; CRISPR-Cas; base editors; clinical study; gene editing; prime editors; translational research.

Figure 1

Summary of the various CRISPR-Cas systems discussed in this review.

Figure 2

A scheme of CRISPR-Cas9 engineering in autologous CAR-T therapy. T cells are extracted from cancer patients and engineered with CRISPR-Cas9 to edit select genes. Later, chimeric antigen receptor (CAR) is randomly inserted into the genome via lentivirus or precisely engineered into a target locus via the CRISPR-Cas9 system to create an engineered autologous CAR-T cell. Engineered CAR-T cells are later given back to the cancer patients.

Figure 3

A scheme of CRISPR-Cas9 engineering in the allogenic CAR-T therapy. T cells are extracted from healthy donors and engineered with CRISPR-Cas9 technology to edit select genes including genes for TCR, PD1, and MHC Class I and II molecules, among others. Later, CAR is randomly inserted into the genome via lentivirus or precisely inserted at a target locus via the CRISPR-Cas9 system to create an engineered allogenic off-the-shelf CAR-T cell. These donor-derived allogenic CAR-T cells are manufactured in scale and given back to multiple cancer patients.

Figure 4

Delivery systems for base editors. (A) Base editors can be delivered directly to patients in vivo, typically through adeno-associated viruses or lipid nanoparticles. The base editor then acts directly in patients (e.g., VERVE-101 edits PCSK9 in the liver). (B) Base editors can also be used to modify T cells or HSCs ex vivo before the edited cells are infused into patients.

Figure 5

Emerging therapeutic applications for RNA editing by Cas enzymes.

Figure 6

Diagram showing the steps to generate large animal models. SCNT: somatic cell nuclear transfer.