MyCRISPRWish.com

CRISPR can be applied in the body in different ways, depending on the target tissue or organ that needs to be edited. There are two main approaches: viral and non-viral delivery.

Viral delivery uses viruses, such as adeno-associated viruses (AAVs), to carry the CRISPR components (Cas9 protein, guide RNA and donor DNA) into specific cells in the body. This method can target tissues such as muscle, lung and central nervous system. For example, a clinical trial sponsored by Allergan plc and Editas Medicine used AAVs to deliver CRISPR to the retina of a patient with a genetic form of blindness. This was the first time CRISPR was used to edit human genes within the body.

Non-viral delivery uses other methods, such as lipid nanoparticles (LNPs), to encapsulate and transport the CRISPR components into the cells. This method can mainly target the liver, where many genetic diseases occur. For example, a clinical trial by Intellia Therapeutics and Regeneron Pharmaceuticals used LNPs to deliver CRISPR to the liver of patients with transthyretin amyloidosis, a rare and fatal disease caused by a mutation in a liver gene. This was the first time CRISPR was used to edit human genes in vivo without using viruses.

Both viral and non-viral delivery methods have advantages and disadvantages, such as efficiency, specificity, safety and immunogenicity. Researchers are working on improving and optimizing these methods for different applications and diseases. CRISPR in vivo has the potential to cure many genetic disorders that are currently untreatable or incurable.

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. These are segments of DNA that are found in bacteria and archaea, which are simple single-celled microorganisms. CRISPR segments act as a defense system against viruses that infect these microbes. They store copies of the viral DNA sequences, which can be used to recognize and destroy the invaders in future attacks.

To do this, bacteria and archaea use CRISPR-associated proteins, or Cas proteins, which are enzymes that can cut DNA. One of the most widely used Cas proteins is Cas9. Cas9 works together with a guide RNA molecule, which is a molecular cousin to DNA. The guide RNA matches the target DNA sequence that needs to be edited. When Cas9 and the guide RNA find the target DNA, Cas9 cuts both strands of the DNA at a specific location.

After cutting the DNA, the cell can either repair the break by joining the two ends back together, or insert a new piece of DNA into the gap. This new piece of DNA can be provided by the researchers who want to edit the gene. By doing this, they can delete, modify or add new genetic information to the cell.