Genome Editing - Shaping the Future of Gene Therapy
Table of Contents:
Introduction to Gene Editing
A scientist working on his PhD in Spain identified genomic sequences in archaea that were repeated up to 600 times in a row in the early 1990s. In the late 1980s, Japanese scientists made a similar discovery in bacteria. Later research discovered that these repeats are part of a prokaryotic immune system. They are employed to retain genetic information on bacterial viruses (bacteriophages) that the organism and its ancestors have been exposed to, as well as ready the organism to defend itself against that invader in the future. Few people would have predicted that this discovery, known as CRISPR, would lead to the current frenzy in mammalian genome editing.
Since the 1970s, genetic engineering has been used to introduce new genetic components into organisms. The random manner with which the DNA is inserted into the host's genome has been a downside of this method, impairing or altering other genes inside the organism.
However, various ways for targeting inserted genes to specific places within an organism's genome have been discovered. It has also made it possible to modify specific sequences inside a genome while reducing off-target effects. Before the advent of the current nuclease-based gene-editing platforms, genome editing was pioneered in the 1990s, but its utility was limited by poor editing efficiency.
Emmanuelle Charpentier of the Max Planck Unit for the Science of Pathogens and Jennifer Doudna of the University of California, Berkeley were jointly awarded the Nobel Prize in Chemistry in 2020 to develop the CRISPR/Cas9 genetic scissors, which have revolutionized genome editing.
What is Genome/Gene Editing?
Genome editing, also known as genome engineering or gene editing, involves inserting, deleting, modifying, or replacing DNA in a living organism's genome. Unlike earlier genetic engineering approaches that randomly inserted genetic material into a host genome, genome editing focuses insertions to specified sites. Editing DNA can alter physical characteristics such as eye colour and disease risk. To achieve so, scientists employ a variety of technologies.
How does Genome/Gene editing work?
Genome editing methods are similar to scissors in that they cut DNA at exact locations. The sliced DNA can then be removed, replaced, or added to as needed.
CRISPR, a genome-editing method that was created in 2009, has made DNA modification easier than ever before. CRISPR is more precise, easier, faster, and less expensive than previous genome editing technologies. CRISPR is utilised by a lot of scientists that do genome editing.
Gene Therapy and Gene Surgery
The initial attempts at "gene therapy" comprised implanting a functional copy of the illness gene into the relevant tissue, in the hopes of partially replacing regular gene activity and therefore curing or at least reducing the harmful consequences of the inherited gene defect. Recent techniques have included attempting "gene surgery" to correct DNA coding faults by converting mutations to the correct, normal sequence. As the first step in the repair process, gene surgery necessitates the availability of enzymes that can target and cut DNA at particular places within living human cells.
The gene-cleavage technology of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) consists of two components: a nuclease (e.g., Cas9), which acts like a pair of scissors and is responsible for cleavage of double-stranded DNA, and a single guide RNA (sgRNA), which forms a complex with the nuclease and provides sequence specificity, essentially "guiding" the Cas nuclease to a single target site within the three billion bases of DNA present in a human genome.
Uses of Gene Editing
Scientists are working on gene therapies, or treatments that involve genome editing, to prevent and treat diseases in humans. Genome editing techniques can help treat diseases with a genetic basis, such as cystic fibrosis and diabetes. There are two types of gene therapies: germline therapy and somatic therapy. Germline therapies lead to alterations in the DNA of reproductive cells (such as sperm and eggs), which are handed down from generation to generation. Somatic therapies, on the other hand, target non-reproductive cells, and any alterations in these cells effect only the person who receives the gene therapy.
Key Facts about Gene Editing
The global genome editing/genome engineering market is estimated to grow at a CAGR of 18.2 percent from USD 5.1 billion in 2021 to USD 11.7 billion in 2026. The rise in government funding and the number of genomics initiatives, as well as expanding application areas of genomics and the advent of CRISPR-Cas9 for genome engineering, are projected to fuel the expansion of the genome editing/genome engineering market.
The services sector is expected to increase at the fastest rate by 2020. Sequencing services, data analysis, bioinformatics services, and other services, such as informatics, clean up, gene expression, and DNA synthesis services, make up the genomic editing/genome engineering services industry.
North America, Europe, Asia Pacific, Latin America (LATAM), and the Middle East and Africa make up the genome editing/genome engineering market (MEA). Government funding should be increased, and R&D infrastructure should be developed. The primary factors driving the growth of the genome editing/genome engineering market in the Asia Pacific region are increased research funding and an increase in the number of applications of gene synthesis for genetic engineering of cells and tissues of organisms. In 2020, the genome editing/genome engineering market was dominated by Thermo Fisher Scientific (US), Merck KGaA (Germany), GenScript (China), and PerkinElmer (US). CRISPR Therapeutics AG (Switzerland), Tecan Life Sciences (Switzerland), Precision Biosciences (US), Agilent Technologies (US), and Cellectis S.A (France) are some of the other major competitors in this sector.
Out of the total, the number of patents equate to 16,824 in the US - which is the highest count of all the countries in the world. China takes the second rank with a total number of 11,817 patents. The European Patent Office has recorded 10306 taking it to the third position. Canada is on the fourth position with 7362 patent applications. Japan holds 7144 patents while Australia has 5852 patents.
Patent Filing Trend Over Last 10 Years
Patenting has seen an upward rise initially and then a steep fall is seen in the trend analysis of over ten years.
The first year saw a record of 1325 patents followed by 1876 and 2849 in the following two years. The fifth year saw a slight spike with 5539 patent applications. 1130 patents were recorded in the eighth year. The number of patent applications saw a steep fall in the tenth year with just 7321 patent applications. It further fell to 3559 in the following year.
Who are the top players in Genome Editing Industry?
PIONEER HI BRED INTERNATIONAL has bagged the first place in the count of patents with 2090 to its credit. MIT ranks second with 1324 patent applications followed by UNIVERSITY OF CALIFORNIA on the third spot with 1262 patent applications. Broad Institute ranks fourth with 1103 applications and Monsanto Technology ranks fifth with 1013 patent applications. These developments can be credited to the robust R&D and constant upgradations in the technical domain.
Technical Roadblocks in the path of Genome Editing
CRISPR is an improvement over prior genome editing technologies, however it is not without limitations. For example, genome editing tools can sometimes cut in the wrong location, and scientists aren't sure how these errors will affect patients. Researchers must analyze the safety of gene treatments and develop genome editing procedures to ensure that they are safe for patients.
Ethical Concerns related to Genome Editing
Scientists and the rest of us should think about the myriad ethical considerations that genome editing can raise, including safety.
Before genome editing can be utilized to treat patients, it must first be proven to be safe. Other ethical issues that scientists and society should examine include:
Is it permissible to perform gene therapy on an embryo when the embryo's consent to treatment is difficult to obtain? Is it sufficient to obtain parental consent?
What if gene therapies are prohibitively expensive, and only the wealthy can afford them? This could exacerbate current health disparities between rich and poor people.
Will some people utilize genome editing to improve attributes that aren't health-related, like athletic aptitude or height?
Should scientists be permitted to modify germline cells in the future?
The majority of individuals think that scientists should not edit the genomes of germline cells at this time due to safety concerns. Scientists worldwide are cautious about germline therapy research since changes to a germline cell would be handed down through generations. For this reason, many governments and organizations have tight restrictions prohibiting germline editing. The National Institutes of Health, for example, does not finance research into human embryo editing.
The International Summit on Human Gene Editing brought together scientists worldwide to discuss these and other ethical concerns.