CRISPR gene technology—the next best thing in medicine

Abstract

The gene-editing technique identified as clustered regularly interspaced palindromic repeats (CRISPR), also known as Cas9, enables quick, inexpensive, and simple correction of genetic errors as well as the inactivation or activation of genes in living cells. The 2 essential components of CRISPR technology are a guide RNA that resembles a chosen target gene and the endonuclease Cas9 (CRISPR-associated protein 9), which alters the genome by cleaving double-stranded DNA1. In 1987, Escherichia coli was found to contain the CRISPR/Cas protein system for the first time, and in 2007 it was found to be a part of the immunologic mechanisms of prokaryotic microorganisms. In bacteria and other prokaryotes, the CRISPR/Cas9 protein immune system has been revealed to be an extremely accurate mechanism permitting acquired immunity. The CRISPR/Cas9 technology was developed by Doudna and Charpentier after they applied this discovery to develop a quick and accurate gene editing method2,3. Two important studies published in 2012 contributed to the development of the straightforward and user-friendly CRISPR-Cas9 genome-editing tool. Researches have demonstrated that any portion of DNA may be sliced using CRISPR technology. By altering the nucleotide sequence of crRNA, which binds to a complementary DNA target, this might be accomplished. The system was further streamlined by Martin Jinek4 and associates by producing a single “guide” RNA. George Church5 asserts that we create 20 nucleotide base pairs that match the desired gene. A complementary RNA molecule is then created using those 20 base pairs. The DNA at that location will then be cut by the RNA and the Cas9 protein. The cell’s natural repair processes start working when the DNA is cut, altering the gene through mutations or other changes. There are 2 ways, in which this might occur. One technique is “nonhomologous end joining,” which refers to fixing the two cuts to glue them together. Here, erroneously added or deleted nucleotides result in mutations that can damage a gene. In the second technique, a nucleotide sequence is used to bridge the gap, repairing the break. A short strand of DNA serves as a template for this in the cell. The ability to introduce any gene or correct a mutation is provided by the researcher’s own DNA template6. For the purpose of diagnosing cancer-specific genetic sequence changes, targeted enzymatic digestion mediated by CRISPR technology can be used. A cancer diagnostic marker known as a microsatellite is discovered when CRISPR-mediated, enzymatic digestion is directed at short tandem repeats7. CRISPR technology allows for the modification of a patient’s T cells and stem/progenitor cells, it then might be administered to the patient once more to treat illnesses. It may be used to treat autoimmune illnesses, primary immune deficits, and solid tumors. A more successful strategy using the CRISPR system has recently been reported by Schumann and colleagues in human CD4+ T cells. Their method made it possible to change the genome in primary human T cells in an experimental and therapeutic manner. They demonstrated that T cells can be manipulated to prevent the expression of the protein PD-1, allowing solid cancers to be targeted by T cells8. In addition, the discovery of apoptotic pathways linked to Parkinson disease-related neurodegenerative processes and a better understanding of various Parkinson's Disease gene interactions have both been made possible by CRISPR. It has also been used to examine certain preventive or compensating mechanisms, such as the Prokineticin-2 signaling route, as well as neuroinflammatory processes involved in the pathophysiology of Parkinson disease, such as the PKC signaling pathway9. Treatment of infectious diseases like human immunodeficiency virus (HIV) represents yet another potential clinical use for CRISPR. Antiretroviral therapy is a treatment for HIV, but because the virus remains permanently ensconced in the host gene, there is no cure as of yet. HIV-1 genome activity could be targeted using CRISPR technology, according to research by Hu et al10. This inhibited HIV gene still expresses and replicates in a variety of cells that have the potential to be latently infected with HIV without causing any toxicity. Potentially eradicating HIV from patients represents a significant therapeutic advance in addressing the issue at hand11. A cardioprotective method presented by Lebek and colleagues may be helpful for many heart disease patients. The CaMKIId’s oxidative activation sites, which are a major contributor to cardiac disease, were disrupted using base editing. When human induced pluripotent stem cells are used to create cardiac muscle cells, ischemia/reperfusion injury is prevented by the edition of CaMKIId gene to remove oxidation-sensitive methionine residues. Furthermore, CaMKIId editing during ischemia/reperfusion injury in mice resulted in heart function recovery as opposed to severe damage. CaMKIId gene editing through CRISPR may, therefore, offer a long-term and cutting-edge method for treating heart disease12. The treatment of genetic disorders brought on by monogenic mutations is another use of CRISPR. Such illnesses include hemoglobinopathies, Duchenne muscular dystrophy, and cystic fibrosis (CF). CRISPR therapy was studied by Schwank et al for CF. Using adult intestinal stem cells derived from CF patients13, one of the common CF mutations in intestinal organoids was effectively corrected. The CF transmembrane conductor receptor function was ultimately recovered after the mutation was corrected14. Treatment for hemoglobinopathies like sickle cell disease and thalassemia may also be possible using CRISPR technology. In both mouse and primary human erythroblast cells, Canver and colleagues demonstrated that CRISPR-mediated disruption of the BCL11A gene enhancer could induce fetal hemoglobin. In the future, such a strategy might enable the expression of fetal hemoglobin when patients have adult hemoglobin that is abnormal15. CRISPR-Cas system can potentially solve the problem of antibiotic resistance by targeting essential genes that are necessary for bacterial fertility and/or nonessential genes on the chromosome or plasmids that depend on the target gene. The problem of antibiotic resistance can be approached by the use of CRISPR-Cas system, as it will be able to target multiple genes in bacterial chromosomes or target resistant plasmids16. Alexander Fleming’s discovery of antibiotics revolutionized medicine, making it possible to cure fatal diseases that were previously thought incurable. Given the transformative impact of antibiotics, it is reasonable to believe that CRISPR, the gene-editing technology, has the potential to bring about a similar revolution in modern medicine. CRISPR-Cas9 is a revolutionary technology with immense potential to positively impact both individuals and communities in the field of medicine. At the individual level, it can offer personalized health care solutions and the potential to cure previously incurable genetic diseases. This could lead to an improved quality of life for those with genetic conditions. At the community level, CRISPR-Cas9 has the potential to bring about significant positive changes in public health. The technology could be used to prevent the spread of diseases by editing the genes of disease-carrying organisms. It could also offer more effective treatments for various diseases, including cancer and HIV, thus reducing the disease burden on health care systems. Although it is still in its early stages, CRISPR-Cas9 has already shown great promise in treating certain genetic diseases. CRISPR-Cas9 could be one of the most significant technological breakthroughs of our time, as such, it can be viewed as a modern-day equivalent of Fleming’s discovery of antibiotics in terms of its potential to revolutionize medicine. It could represent the frontier of medical breakthroughs in the years to come. Ethical approval Not applicable. Sources of funding The authors received no extramural funding for the study. Author contributions H.S.R. and L.A.: conceptualization. B.S.R., H.F., L.A., and M.A.: literature and drafting of the manuscript. H.S.R.: editing and supervision. Conflict of interest disclosures The authors declare that they have no financial conflict of interest with regard to the content of this report. Research registration unique identifying number (UIN) Not applicable. Guarantor All authors take responsibility for the work, access to data and decision to publish.