What diseases does CRISPR-Cas9 treat?
Interestingly, CRISPR-Cas9 could be used to the investigation of treatments of various human hereditary diseases such as hemophila, β-thalassemia, cystic fibrosis, Alzheimer's, Huntington's, Parkinson's, tyrosinemia, Duchnene muscular dystrophy, Tay-Sachs, and fragile X syndrome disorders.
What kind of disease would be best targeted using CRISPR-Cas9?
Scientists are studying CRISPR for many conditions, including high cholesterol, HIV, and Huntington's disease. Researchers have also used CRISPR to cure muscular dystrophy in mice. Most likely, the first disease CRISPR helps cure will be caused by just one flaw in a single gene, like sickle cell disease.
What known diseases has CRISPR been used for in clinical trials?
Right now, CRISPR-based therapies are mainly aimed at treating blood cancers like leukemia and lymphoma. A trial in China for a type of lung cancer was recently completed, as well.
Which diseases are suitable targets for genome editing?
Current preclinical research on genome editing primarily concentrates on viral infections, cardiovascular diseases (CVDs), metabolic disorders, primary defects of the immune system, hemophilia, muscular dystrophy, and development of T cell-based anticancer immunotherapies.
Can CRISPR be used for Alzheimer's?
In recent years, due to the short experimental period and relatively low consumption of CRISPR/Cas9 technology, CRISPR/Cas9 is currently widely used in the AD field including construction of AD model, screening pathogenic genes, and target therapy.
Is CRISPR being used to treat cystic fibrosis?
New CRISPR/Cas9 technique corrects cystic fibrosis in cultured human stem cells. Summary: Researchers corrected mutations that cause cystic fibrosis in cultured human stem cells. They used a technique called prime editing to replace the 'faulty' piece of DNA with a healthy piece.
For which disease CRISPR has been used for its cure and clinical trial?
Cancer. China has been spearheading the first clinical trials using CRISPR-Cas9 as a cancer treatment. One of these studies was testing the use of CRISPR to modify immune T cells extracted from the patient. The gene-editing technology is used to remove the gene that encodes for a protein called PD-1.
What disease is the first human CRISPR trial?
In the trial, six people with a rare and fatal condition called transthyretin amyloidosis received a single treatment with the gene-editing therapy. All experienced a drop in the level of a misshapen protein associated with the disease.
What diseases can gene therapy cure?
Gene therapy holds promise for treating a wide range of diseases, such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS. Researchers are still studying how and when to use gene therapy. Currently, in the United States, gene therapy is available only as part of a clinical trial.
Can CRISPR cure sickle cell anemia?
A small clinical trial of a CRISPR cure for sickle cell disease, approved earlier this year by the U.S. Food and Drug Administration, has received $17 million to enroll about nine patients, the first of which may be selected early next year.
How could CRISPR help treat genetic diseases like DMD or hemophilia?
CRISPR-Cas can be used to permanently repair the mutated DMD gene, leading to the expression of the encoded protein, dystrophin, in systems ranging from cells derived from DMD patients to animal models of DMD.
Can CRISPR cure autoimmune disease?
They have shown they can use CRISPR to correct the mutation in immune cells derived from the family, suggesting that gene editing could treat rare autoimmune conditions.
What are some examples of CRISPR/CAS9?
Double stranded DNA breaks are subsequently repaired by cellular DNA repair machinery via the NHEJ or HDR pathway. (b)dCas9 fused with transcriptional activators or repressors activates or inhibits the expression of a target gene. These systems are called CRISPRa or CRISPRi. dCas9 indicates catalytically inactive dead Cas9, which is able to bind the target DNA without cutting. CRISPRa, CRISPR activators to activate transcriptional process; CRISPRi, CRISPR inhibitors to interference transcriptional process. (c)Base editors are the combination of Cas9 D10A nickase with cytidine or adenine deaminase to induce G->T or A->G transition. Prime editor, different from base editors, is the fusion protein of Cas9 H840A nickase and reverse transcriptase. It can achieve up to 12 types of base-to-base conversions, and targeted insertions and deletions without DSBs or donor DNA templates. pegRNA, prime editing guide RNA.
What is CRISPR/CAS?
CRISPR/Cas genome editing is a simple, cost effective, and highly specific technique for introducing genetic variations. In mammalian cells, CRISPR/Cas can facilitate non-homologous end joining, homology- directed repair, and single-base exchanges. Cas9/Cas12a nuclease, dCas9 transcriptional regulators, base editors, PRIME editors and RNA editing tools are widely used in basic research. Currently, a variety of CRISPR/Cas-based therapeutics are being investigated in clinical trials. Among many new findings that have advanced the field, we highlight a few recent advances that are relevant to CRISPR/Cas-based gene therapies for monogenic human genetic diseases.
What is the purpose of CRISPR/CAS?
The CRISPR/Cas system was originally discovered as a prokaryotic adaptive immunity system used to recognize and cleave invading nucleic acids 6-8. Based on this prokaryotic system, scientists have engineered a series of CRISPR/Cas tools for genome editing in mammalian cells, with the list of CRISPR/Cas systems in use continuing to expand. The most commonly used Cas nuclease comes from Streptococcus pyogenes(SpCas9), and belongs to the type II CRISPR system. SpCas9 was the first to be reprogrammed for genome editing in mammalian cells. For specific nucleotide sequence recognition, engineered SpCas9 relies on the guidance of a single-guide RNA (sgRNA). Typically, sgRNA is composed of a scaffold sequence that is bound by the Cas protein, and a custom-designed ∼20 nucleotide spacer that defines the genomic target to be modified. Following hybridization of the spacer to a target genomic sequence that is positioned next to a protospacer adjacent motif (PAM), the target DNA is cleaved, leading to a double-strand break (DSB) 7-9. The Cas-mediated DSB is subsequently repaired by cellular DNA repair machinery via homology- directed repair (HDR) or the non-homologous end joining (NHEJ) pathway. NHEJ can be used to produce insertions and deletions (indels) that disrupt or inactivate the target gene, while HDR can be used for precise nucleotide sequence modifications, such as point mutation correction 10-12(Figure Figure11a).
What is Cas9 used for?
dCas9 can also be used as a visualization tool . Chen and colleagues have used dCas9 fused to enhanced green fluorescent protein (EGFP) to visualize repetitive DNA sequences using one sgRNA, or nonrepetitive loci using multiple sgRNAs 16-18. In addition, David R. Liu's group has fused D10A Cas9 nickase with either cytidine or adenine deaminase to generate cytidine base editors (CBEs) and adenine base editors (ABEs), respectively. CBEs and ABEs generate transitions between A•T and C•G base pairs without causing high levels of double-stranded DNA cleavage in the target genomic region. Importantly, the Liu's group has extended base editing to utilize H840A Cas9 nickase fused with reverse transcriptase to create prime editors (PEs), which can achieve all possible base-to-base conversions (12 in total), as well as targeted insertions and deletions without DSBs or donor DNA templates 19(Figure Figure11c).
What is LCA10?
Leber congenital amaurosis (LCA) is a rare genetic eye disease manifesting severe vision loss at birth or infancy. LCA10 caused by mutations in the CEP290gene is a severe retinal dystrophy. CEP290gene (~7.5 kb) is too large to be packaged into a single AAV. To overcome this limitation, Editas Medicine developed EDIT-101, a candidate genome editing therapeutic, to correct the CEP290splicing defect in human cells and in humanized CEP290 mice by subretinal delivery. This approach uses SaCas9 to remove the aberrant splice donor generated by the IVS26 mutation. In the human CEP290 IVS26 knock-in mouse model, over 94% of the treated eyes achieved therapeutic target editing level (10%) when the dose of AAV was not less than 1 × 1012vg/ml 53. Allergan and Editas Medicine have initiated a clinical trial of EDIT-101 for the treatment of LCA10 (Table Table33).
How is CRISPR used in research?
To date, CRISPR/Cas systems have been used to investigate target genes in genome modification 22, splicing 23, transcription 24and epigenetic regulation 25, and have been applied in a research setting to investigate and treat genetic diseases 26, infectious diseases 27, cancers 28, and immunological diseases 29, 30. Among the exciting advances, translational use of CRISPR/Cas in monogenic human genetic diseases has the potential to provide long-term therapy after a single treatment. In this section, we summarize the recent applications of the CRISPR/Cas system in the generation of disease models and in the treatment of genetic diseases in vitroand in vivo.
Why is CRISPR used in disease models?
CRISPR/Cas has been widely used for creating disease-related cellular models , such as DMD 31, aniridia-related keratopathy (ARK) 32, brittle bone 33, X-linked adrenoleukodystrophy (X-ALD) 34, and Alzheimer's disease 35. Moreover, researchers have created a series of mouse models using CRISPR/Cas that recapitulate DMD 36, atherosclerosis 37, obesity and diabetes 38, RTHα 39, and Alzheimer's disease 40(Table Table11). One example is the development of a mouse model for ryanodine receptor type I-related myopathies (RYR1 RM), which harbors a patient- relevant point mutation (T4706M) engineered into one allele, and a 16-base pair frameshift deletion engineered into the second allele of the RYR1 gene. Subsequent experiments demonstrated that this mouse model of RYR1 RM is a powerful tool for understanding the pathogenesis of recessive RYR1 RM, and for preclinical testing of therapeutic efficacy 41. CRISPR/Cas has also been used to generate disease models in large animals, including sheep 42, rabbit 43, pig 44, and monkey 45. For example, a monkey model was developed to study Parkinson's disease by introducing a PINK1deletion and revealed a requirement for functional PINK1 in the developing primate brain 45. CRISPR/Cas technology offers a flexible and user-friendly means of developing disease models to explore the genetic causes of diseases and evaluate therapeutic strategies.
What is CRISPR/CAS9?
Clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 is a gene-editing technology causing a major upheaval in biomedical research. It makes it possible to correct errors in the genome and turn on or off genes in cells and organisms quickly, cheaply and with relative ease. It has a number of laboratory applications including rapid generation of cellular and animal models, functional genomic screens and live imaging of the cellular genome.1It has already been demonstrated that it can be used to repair defective DNA in mice curing them of genetic disorders,2and it has been reported that human embryos can be similarly modified.3Other potential clinical applications include gene therapy, treating infectious diseases such as HIV and engineering autologous patient material to treat cancer and other diseases. In this review we will give an overview of CRISPR/Cas9 with an emphasis on how it may impact on the specialty of paediatrics. Although it is likely to have a significant effect on paediatrics through its impact in the laboratory, here we will concentrate on its potential clinical applications. We will also describe some of the difficulties and ethical controversies associated with this novel technology.
What is the purpose of CRISPR/CAS9?
CRISPR/Cas9 is a gene-editing technology which involves two essential components: a guide RNA to match a desired target gene, and Cas9 (CRISPR-associated protein 9)—an endonuclease which causes a double-stranded DNA break, allowing modifications to the genome (see figure 1).
What disease is CRISPR used for?
Tabebordbar et alrecently used adeno-associated virus (AAV) delivery of CRISPR/Cas9 endonucleases to recover dystrophin expression in a mouse model of DMD, by deletion of the exon containing the original mutation. This produces a truncated, but still functional protein. Treated mice were shown to partially recover muscle functional deficiencies.5Significantly, it was demonstrated that the dystrophin gene was edited in muscle stem cells which replenish mature muscle tissue. This is important to ensure any therapeutic effects of CRISPR/Cas9 do not fade over time. Two similar studies have described using the CRISPR/Cas9 system in vivo to increase expression of the dystrophin gene and improve muscle function in mouse models of DMD.67Other studies have used CRISPR/Cas9 to target duplication of exons in the human dystrophin gene in vitro and have shown that this approach can lead to production of full-length dystrophin in the myotubules of an individual with DMD.8
What is the potential of CRISPR?
CRISPR/Cas9 technology has the potential to revolutionise the treatment of many paediatric conditions.
Can CRISPR be used in pluripotent stem cells?
There is also interest in using CRISPR/Cas9-mediated genome editing in pluripotent stem cells or primary somatic stem cells to treat disease. For example Xie et al12showed the mutation causing β-thalassaemia could be corrected in human induced pluripotent stem cells ex vivo. They suggest that in the future such an approach could provide a source of cells for bone marrow transplantation to treat β-thalassaemia and other similar monogenic diseases.
Can CRISPR be used to modify T cells?
There has been increasing interest in the possibility of using CRISPR/Cas9 to modify patient-derived T-cells and stem/progenitor cells which can then be reintroduced into patients to treat disease. This approach may overcome some of the issues associated with how to efficiently deliver gene editing to the right cells.
Can CRISPR be used for fetal haemoglobin?
CRISPR/Cas9 could also be used to treat haemoglobinopathies. Canver et al9recently showed BCL11Aenhancer disruption by CRISPR/Cas9 could induce fetal haemoglobin in both mice and primary human erythroblast cells. In the future such an approach could allow fetal haemoglobin to be expressed in patients with abnormal adult haemoglobin. This would represent a novel therapeutic strategy in patients with diseases such as sickle cell disease or thalassaemias. Knock-in of a fully functional β-globin gene is much more challenging, which is the reason for this somewhat unusual approach.
Abstract
The new coronavirus SARS-CoV-2 pandemic has put the world on lockdown for the first time in decades. This has wreaked havoc on the global economy, put additional burden on local and global public health resources, and, most importantly, jeopardised human health.
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgement
The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University, Abha 61413, Saudi Arabia for funding this work through research groups program under grant number R.G.P-1-223-42.