Therapy of Genetic Diseases

Weiying Jiang

Department of medical genetics

Gene Therapy

Conventional Approaches

Therapy of Genetic Diseases

Dietary Therapy

Protein and Enzyme replacement

Pharmacal Therapy

Surgery

Conventional Approaches

Dietary Therapy

Protein and Enzyme replacement

HemophiliaFactor Ⅷ

Replacement

Protein and Enzyme replacement

Enzymatic Therapy

β-glucosidase β-glucosidase

Gaucher disease

Lysosome

Pharmacal Therapy

Prenatal Therapy

Patient Therapy

Substitution

Addition

Remove surplus

Vitamine

Substitution

Dwarf

Growth hormone

sodium dimercaptosulphonate ，(DMPS)

Cu++

Wilson’s Disease

Remove surplus

Remove surplus

Statins

Lower cholesterol

LDL receptor

Increased LDL clearance form plasma

Inhibiting HMG-CoA

reducease

heparin

agarose

Ca2Cl

Blood filter

Familial hypercholesterolemia

Surgery

Orthopedics

Cleft lip

Presymptom Therapy

Familial polyposis coli.

Transplantation

Therapeutic applications of recombinant DNA Technology

Pig pancreas

Insulin

Therapeutic applications of recombinant DNA

Technology

Insulin

Gene Therapy

The deliberate introduction of genetic material into human somatic cells for therapeutic, prophylactic or diagnostic purposes.

Protocols of Gene therapy

Somatic versus Germline Gene therapy

Ex vivo versus in vivo Gene therapy

Somatic Cell Gene therapy

Manipulating the genome of somatic cells in selected tissues .The effect of the therapy are planned to be limited to the individual undergoing treatment and are not designed to introduce potentially heritable genetics modification.

Germline Gene therapy

It is possible to permanently modify the germline of animals,which makes the young generation normally .In theory, it should be possible to do in people.

Transfer of the target DNA

Physical Method

Chemical Method

Membrane integration

Virus vector

Receptor system

Homo-recombination

Physical Method

Injection

Electroporation

DNA

DNA

DNA

Micro-particle Bombardment

Micro -particle of Gold or Wolfram

DNA

Gene Gun

Very high speed

Membrane integration

lipisome delivery system

A lipisome is an ambipathic molecular capable of binding to DNA and incorporating it into a lipid bilayer which facilitates endocytic entry of the DNA into cells.

p346

lipid bilayer Cationic

DNA-lipid complex

Virus Vector

The process of using a virus to carry a foreign gene into a cell is referring to as transduction.

Virus Vector

Retrovirus

Lentivirus

Adenovirus

Adeno-Associated Virus

Herpesvirus

5‘ 3’

LTR gag pol env LTR

U3 R U5 U3 R U5ψ

Mo-MLV Structure

(Moloney-Murine Leukemia Virus)

5’ 3’

U3 R U5 U3 R U5ψ Target DNA

Replication Defective- Virus

U3 R U5 U3 R U5

gag pol env

Help virus

Approaches of Gene therapy

Ex vivo Gene therapy (p344)

The cells to be modified are first removed

from the patient genetically modified in

tissue culture, then returned to the patient.

Approaches of Gene therapy

DNA recombination

In vivo Gene therapy

Attempt to treat the patient with a gene

delivery vehicle that will transfer the

target gene to the appropriate target organ

and directly modify the genome of the

target cells.

Gene Therapy Strategies

RNA modification

Target gene correction

Somatic stem-cell therapy

Embryonic stem-cell therapy

RNA modification

Ribozymes

RNAi

Antisense Technology

Regulation of gene expression—

Antisense Technology

A method for negating gene expression involves in the introduction of a single strand DNA, RNA or even synthetic nucleic acid derivative that is complementary to the sequence of the target gene. The complementary antisense nucleic acid can then bind to the single mRNA translated from the targeted gene to create a double strand molecule that is no longer able to translate.

DNA Antisense DNA

transcription

RNA Sense Strand

RNA

Antisense RNA

Human β-globin

E1 E2 E3

Intron1 Intron2

GT AG

Human β-Globin IVS-2 654(C T) 突变

E1 E2 E3

Intron1 Intron2

GT AGGTAG

GT AG

Human β-Globin IVS-2 654(C T) 突变

E1 E2 E3

Intron1 Intron2

GT AGGT

GT AG

Human β-globin

E1 E2 E3

Intron1 Intron2

GT AG

Ribozymes

RNA digestion

transcription blocked

RNA interference, RNAi

Andrew Fir Craig mello

RNA interference (RNAi )

RNAi silencing is triggered by

double-stranded RNA .

Artificial generation of dsRNA from a hairpin construct

Double DNA

siRNAs

RNA-induced silencing complex (RISC )

Containing targets cognate mRNAs for inactivation

Dicer

In situ repair:

5’ATCGGGTCAATTCGA3’ mutation

3’TAGCCAAGTTAACGA5’

5’ATCGGGGCAATTCGA3’ wild

3’TAGCCACGTTAACGA5’

Target gene correction

Stem-cells transplantation

Stem-cells transplantation

Stem cells are unspecialized cells that

defined by their capacity for self-renewal

and the ability to differentiate into the cell

types found in the tissue which they are

derived.

Stem-cells transplantation

Somatic stem-cells transplantation

Bone marrow transplantation

Risk of infection Graft-versus

host disease

Limit donors

Disadvantage

Gene therapy using embryonic stem cells

中山大学中山医学院医学遗传学教研室

蒋玮莹