Trending Topics in Biotechnology: Gene Therapy

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  • What is Genetic Engineering?

GHR: “a type of gene editing, involving the introduction of genetic material into cells to compensate for abnormal genes or to make a beneficial protein”
All organisms generated through genetic engineering are considered to be GMOs.
There are several applications of genetic engineering:
- Agriculture
- Medicine
- Research
- Industry


  • Genome Editing Techniques

The basic working principle of major genome-editing technologies.
- Meganucleases
These are engineered restriction enzymes that recognize long stretches of DNA sequences.
- Zinc Finger Nucleases
These are restriction enzymes that are engineered to recognise the specific desired triplet DNA sequence
These are restriction enzymes that are engineered to recognise any location via protein-DNA interaction
This is a natural defence mechanism in bacteria adopted for simple RNA–DNA base pairing and the PAM sequence determine CRISPR targeting specificity


  • CRISPR – The Biggest Science Story of the Decade.

1. Discovery
- CRISPR was first discovered in 1987 by Yoshizumi Ishino at Osaka University Japan.
- This technology was proposed for programmable gene editing in 2012 by Jennifer Doudna and Emmanuelle Charpentier at UC Berkeley
2. Method
- Viral DNA is injected into the bacterial cell to cause infection.
- When the bacterial cell detects the presence of foreign DNA, it produces an RNA-Protein (Cas-9) complex, that matches that of the viral DNA.
- Cas-9 is a nuclease, a type of enzyme that cuts the DNA, therefore rendering the viral DNA ineffective.
3. Application
- Researchers found that this complex can be engineered to cut any DNA sequence at a precisely chosen location in vivo.
- The cut strand is then repaired by insertion of new nucleotides, either randomly or by with the desired sequence.
- This method will have applications in basic research, drug development, agriculture and human disease


  • Gene Therapy vs Cell Therapy

Gene Therapy
An approach of treating disease by modifying gene expression by:
Replacing a mutated gene
Inactivating or knocking out a mutated gene
Introducing a new gene
Mode of Action
-Therapeutic genetic material could be transferred to in vivo or ex vivo to somatic or germline cells.
-A vector, often a virus (AAV) or physical/chemical methods to deliver a new working gene or genetic material into the cell.
-20 Gene Therapy Products approved(FDA) e.g. Luxturna(Novartis), Macugen(Pfizer), Glybera(AMT)
-2000+human gene therapy clinical trials worldwide
Cell Therapy
An approach of treating disease whereby cellular material (i.e. living cells) is injected, grafted or implanted into a patient.
Mode of Action
-Cells that are pluripotent/multipotent stem are injected into the site of injury, where they replace damaged tissue and facilitate the improved function of the organ/tissue
-Cells that are able to release soluble factors like chemokines, cytokines or growth factors act in a paracrine or endocrine manner to facilitate self-healing.
-Stem Cell Therapy–Embryonic, Mesenchymal, Neural, Hematopoietic
-CAR T-Cell Therapies–Kymriah(Novartis) & Yeskarta(Gilead)


  • What are T-cells?

T-cells are a type of white blood cell (immune cells) that are cable to search and destroy any foreign invaders.
These cells recognise ‘non-self antigens’ and generate responses to eliminate the pathogen or pathogen-infected cells
What does CAR stand for?
CAR refers to chimeric antigen receptors, which are proteins that have been engineered to give the T-cell the ability to target a specific protein
These receptors are chimeric as they combine both antigen-binding and T-cell activating functions into a single receptor.