User:Jaswanth Roy Navana/CRISPR

Applications of CRISPR

The CRISPR technique has a positive response in working towards different disorders like Nervous system, Circulatory system, Stem cells, blood disorders, muscular degeneration. This tool has made advanced approaches in both therapeutic and biomedical systems and some of the applications are discussed below,

1.1 β-Hemoglobinopathies

This disease comes under genetic disorders which are caused by mutation occurring in the structure of hemoglobin or due to substitution of different amino acids in globin chains. Due to this, the red blood cells (RBC) cause a string of obstacles such as failure of heart, hindrance of blood vessels, defects in growth and optical problems. To rehabilitate β-hemoglobinopathies, the patient's multipotent cells are transferred in a mice model to study the rate of gene therapy in ex-vivo which results in expression of mRNA and the gene being rectified. Intriguingly RBC half-life was also increased.

1.2 Hemophilia

It is a loss of function in blood where clotting factors do not work properly. There are two types, Hemophilia A and Hemophilia B. By using CRISPR-Cas9, a vector is inserted into bacteria. The vector used is Adenoviral vector which helps in correction of genes. Doubtlessly, CRISPR has given hope for the treatment of hemophilia by setting right the genes.

1.3 Neurological disorders

CRISPR is used in suppressing the mutations which cause gain of function and also repairs the mutations with loss of functions with gene editing in neurological disorders. The gene editing tool setup a foothold in vivo application for assimilation of molecular pathways.

1.4 Blindness

The Eye disorders became more impediment for the doctors to treat the victims. Moreover, the retinal tissue present in the eye is free from body immune response. The most commonly occurring worldwide eye diseases are cataract and retinitis pigmentosa (RP). These are caused by a missense mutation in the alpha chain that leads to permanent blindness. The approach of CRISPR is to bag the gene coding retinal protein and edit the genome which results in good vision.

1.5 Cardiovascular diseases

The CRISPR technology works more efficiently towards diseases related to the heart. Due to deposition of cholesterol in the walls of the artery leads to blockage of flow of blood. This is caused by mutation in low density lipoprotein cholesterol receptors (LDLC) which results in release of cholesterol into blood in higher levels. This can be treated by deletion of base pair in exon 4 of LDLC receptor. This is a nonsense mutation.

Applications of CRISPR in agriculture

The application of CRISPR in plants was successfully achieved in the year 2013. CRISPR Cas9 has become an influential appliance in editing genomes in crops. It made a mark in present breeding systems.

2.1 Boosting the yield

For high production of yield in cereals the balance of cytokinin is changed. cytokinin oxidase/dehydrogenase (CKX), is an enzyme, so the gene that codes this enzyme was knocked out for more yield to be produced.

2.2 Enhancing quality

Grains have a high amount of amylose polysaccharide. To decrease the amylose content CRISPR is used to alter the amino acids which leads to low production of saccharide. Moreover, wheat contains gluten proteins due to which some of them are intolerant to gluten and cause a disorder called coeliac disease. The gene editing tool targets the gluten genes which results in low gluten production in wheat.

2.3 Resistance to disease

The biotic stress of plants can be reduced by using CRISPR tools. The bacterial infections caused on the rice leads to activation of transcription of genes, the products of these are susceptible to disease and by using CRISPR scientists were able to generate lines of resistance.

General applications of CRISPR

3.1 Gene Therapy

The overall genetic disorders discovered till now are about 6000. Most of them do not have treatment till date. The role of gene therapy is to substitute with exogenous DNA in the place of defective genes and edit the mutated sequence. This therapy made a huge impact in medical biotechnology.

3.2 Base editing

They are two types of base editing’s:

Cytidine base editor is a novel therapy in which the cytidine (C) changes to thymidine (T).

Adenine base editor (ABE), in this there is a change in base complements from adenine (A) to Guanine (G).

The mutations were directly installed in cellular DNA so that the donor template is not required. The base editing’s can only edit point mutations moreover they can only fix up to four-point mutations. So, to master this problem CRISPR system has introduced a new technique known as Cas9 fusion to stretch the level of genome editing.

3.3 Gene silencing and activating

Furthermore, the CRISPR Cas9 protein can modulate genes either by activating or silencing based on genes of interest. There is a nuclease called dCas9 (endonuclease) used to silence or activate the expression of genes.

Limitations in Applications of CRISPR

The researchers are facing many challenges in gene editing. The major hurdles coming in the clinical applications are ethical issues and the transport system to the target site. As the units of CRISPR system taken from bacteria, when they are transferred to host cells it produces an immune response against them. Physical, chemical, viral vectors are used as vehicles to deliver the complex into the host. Due to this many complications are arising such as cell damage that leads to cell death. In the case of viral vectors, the capacity of the virus is small and Cas9 protein is large. So, to overcome these new methods were developed in which smaller strains of Cas9 are taken from bacteria. Finally, a great extent of work is still needed to improve the system.