Gene therapy

mohd muzahid
(M.Pharm (pharmacology)
1st year
integral university lucknow

1. Submitted By:
Mohd Muzahid
M.Pharma(Pharmacology
1
st
year)
Submitted To:
INTEGRAL
UNIVERSITY
Lucknow 104/10/2018

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3. Gene therapy is an experimental technique for
correcting defective gene that are responsible for
disease development.
The most common form of gene therapy involves
inserting a normal gene to replace an abnormal
gene.
The first approved gene therapy experiment
occurred on september 14,1990 in US, when
Ashanti DeSilva was treated for ADA-SCID.
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4. Other approaches used:
• Replacing a muted gene that causes disease with a
healthy copy of the gene.
•Introducing a new gene into the body to help fight a
disease.
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5. •Researchers are studying gene therapy for a number of
diseases, such as
Severe combined immuno-deficiencies(SCID)
Hemophilia
Perkinson’s disease
Cancer
HIV
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Types of Gene Therapy

7.  Therapeutic genes transferred into
the somatic cells.
 E.g.. Introduction of gene into bone
marrow cells, blood cells, skin cells
etc.
 Will not be inherited later
generation.
 At present all researches directed to correct
genetic defects in somatic cells.
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Somatic Gene Therapy

8. Therapeutic genes transferred into the germ cells.
E.g.. Gene introduced into eggs and sperms.
It is heritable and passed on to later generations.
For safety, ethical and technical reason, it is not being
attempted at present.
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Germ Line Gene Therapy

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Types of Somatic Gene Therapy

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Ex vivo Gene Therapy

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1
st
gene therapy – to correct deficiency of enzyme, Adenosine
deaminase (ADA).
Performed on a 4yr old girl Ashanthi DeSilva.
Was suffering from SCID-Severe Combined Immunodeficiency.
Caused due to defect in gene coding for ADA.
Deoxy adenosin accumulate and destroys T lymphocytes.
Disrupts immunity, suffer from infectious disease and die at
young age.
Example of Ex Vivo Gene Therapy

12. Introduction gene directly into tissues or
organs
without removing body cells.
Challenge is delivery only to intended tissues
Viruses act as vectors for gene delivery , but
some injected directly into tissues
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In Vivo Gene Therapy

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Example of In Vivo Gene Therapy
 In patients with cystic fibrosis, a protein called cystic
fibrosis transmembrane regulator (CFTR) is absent due
to a gene defect.
 In the absence of CFTR chloride ions concentrate within
the cells and it draws water from surrounding .
 This leads to the accumulation of sticky mucous in
respiratory tract and lungs.
 Treated by in vivo replacement of defective gene by
adenovirus vector.

14. To transfer the desired gene into a target cell, a
carrier is required. Such vehicles of gene delivery are
known as vectors.
Two main classes
 Viral vectors
 Non viral vectors
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Vector In Gene Therapy

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 Viruses introduce their genetic material into the host
cell as part of their replication cycle.
 Remove the viral DNA and using the virus as a vehicle
to deliver the therapeutic DNA.
 The viruses used are altered to make them safe,
although some risks still exist with gene therapy.

16. A number of viruses have been used for human
gene therapy, including:
 Retrovirus
 Adenovirus
 Adeno-associate virus
 Harpes simplex virus
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Type of Viral Vectors

17. 1.Pure DNA construct .
•Direct introduction of pure DNA construct into tissue.
•Efficiency of DNA uptake by cells and expression rather low.
•Consequently large quantities of DNA have to be injected
periodically.
2.DNA Molecular conjugation.
•Commonly used synthetic conjugate is poly –L- lysine bound to
specific target cell receptor.
•Therapeutic DNA is then made to combine with the conjugate
to form a complex.
•Its avoids lysosomal breakdown.
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Non Viral Vectors System

18. 3.Lipoplexes.
•Lipid DNA complexes;DNA construct surrounded by artificial
lipid layer.
•Most of it gets degraded by lysosomes.
4.Human artificial chromosomes.
•Can carry a large DNA ie, with one or more therapeutic gene
with regulatory elements
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Cont....

19. Physical Method
1-Gene Gun-
•Employs a high-pressure delivery system to shoot
tissue with gold or tungsten particles that are coated
with DNA.
2-Micro Injection-
•Process of using a glass micropipette to insert microscopic
substances into a single living cell.
•Normally performed under a specilized optical microscope setup
called a micromanipulator.
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Method of Gene Therapy

20. Chemical Method
1-Using Detergent Mixture-
•Certain charged chemical compounds like calcium phosphates
are mixed with functional cDNA of desired function.
•The mixture is introduced near the vicinity of recipient cells.
•The chemical disturbs the cell membrane, widens the pore size
and allows cDNA pass through the cell.
2-Lipofection
•It is a technique used to inject genatic material into a cell by
means of liposomes.
•Liposomes are artificial phospholipids vesicles used to deliver a
variety of molecules including DNA into the cell.
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Cont…

21. List of Advantages of Gene Therapy:
It has the ability to replace defective cells.
It is a possible cure for heart disease, AIDS and cancer.
 It can help eradicate diseases from the future
generations.
List of Disadvantages of Gene Therapy
It can damage the gene pool.
It would modify human capabilities.
It has the potential to give rise in other disorders
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Advantages & Disadvantages of gene therapy

22. •Genetic disorder (deficiency ): OTC
•Cancer
- Genetic predisposition
- Mutation in oncogene or tumor supperssor gene.
•Autoimmunity Disease: Rheumatoid arthritis
- Delivery of counteracting gene
•Diseases involves several gene and the
environmental intract:Diabetes
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Application of Gene Therapy

23. Dubey R.C,A Textbook of biotechnology, 1
st
edition (2004), S
Chand and company , New Delhi.
Gupta P.K Elements of biotechnology,1
st
edition (2001)
,Rastogi Publications, Meerut.
Satyanarayna U,Biotechnology ,1
st
edition ,book and allied (P)
Ltd, Kolkata.
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