Era of Genomic Medicine: A Narrative Review on CRISPR Technology as a Potential Therapeutic Tool for Human Diseases.

Odatha W Kotagama,Thelma Abeysinghe,Chanika D Jayasinghe

doi:10.1155/2019/1369682

Abstract

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) provides acquired immunity in microorganisms against exogenous DNA that may hinder the survival of the organism. Pioneering work by Doudna and Charpentier in 2012 resulted in the creation of the CRISPR/Cas9 genome editing tool on the basis of this concept. The aim of this was to create a rapid, efficient, and versatile genome-editing tool to facilitate genetic manipulation. The mechanism relies on two components: the RNA guide which acts as a sentinel and a Cas protein complex which functions as a highly precise molecular knife. The guide RNA can be modified to match a DNA sequence of interest in the cell and accordingly be used to rectify mutations that may otherwise cause disease. Within a few years following the development of the CRISPR/Cas9 tool, its usage has become ubiquitous. Its influence extends into many fields of biological sciences from biotechnology and biochemistry to molecular biology and biomedical sciences. The following review aims at shedding some light on to the applications of the CRISPR/Cas9 tool in the field of biomedical sciences, particularly gene therapy. An insight with relation to a few of the many diseases that are being tackled with the aid of the CRISPR/Cas9 mechanism and the trends, successes, and challenges of this application as a gene therapy are discussed in this review.

Highlights

Understanding the genetic basis of human diseases has allowed for substantial progress in biomedical research
A large amount of works have been done with the use of zincfinger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs) with success being achieved through each mechanism, and scientists have begun to turn their attention to the use of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 tool as well
Promising work was carried out by De Ravin et al [46], and it was shown that the CRISPR/Cas9 protein geneediting tool was used to correct mutations in blood stem cells of patients suffering from Chronic granulomatous disease (CGD). 31% of cells exhibited gp91phox expression, and when corrected cells were engrafted into mice, stable expression of the gp91phox gene was observed for five months [45]

Summary

Introduction

Understanding the genetic basis of human diseases has allowed for substantial progress in biomedical research. In CRISPR/Cas, accurate site-specific changes are mediated by programmable RNA and a restriction enzyme complex referred to as Cas gives rise to a highly efficient gene-editing tool [6] Over the years, this system has been applied in biomedical research, aiming at developing therapeutic interventions for monogenic as well as multifactorial diseases [4]. The cellular mechanism will direct the cell to proceed with nonhomologous end joining (NHEJ) of fragments or with homology-directed repair (HDR) While the former is a rapid and simple process essentially allowing the two separated components of the DNA molecule to join together, it is inefficient and can generate errors by frameshift mutations [14]. Microhomology-mediated base pairing together with CRISPR has been developed to form an efficient tagging tool that will greatly aid functional analysis of proteins in their native state [18]

Common Genomic Editing Approaches

Findings

Multifactorial Diseases