Future prospect for cell and molecular therapy

Question 1

New therapies

Answer 1

Disability > with age & pop. > in age
Most tissues have limited potential to regenerate
Advances in cell, molecular (genome project) and developmental biology
Cost, effectiveness, public expectation

Question 2

Stem cells

Answer 2

Undifferentiated cells which have potential for self renewal and can give rise to one and sometimes many different cell types

Question 3

Embryonic stem cells

Answer 3

Pluripotent

Any type of cell in the adult

Question 4

Adult stem cells

Answer 4

Multipotent
Form limited number of cell types
Found in bone marrow, most organs
Little more ‘plastic’ than previously thought
Used for 50 years (bone marrow transplantation)

Question 5

Growing teeth

Answer 5

Bioengineered tooth erupted and physiologically similar to natural teeth
Wisdom tooth germs could be used in young
Futher studies need to identify tooth-inducible stem cells in elderly
Expectation: autologous transplantation of bioengineered tooth germ reconstructed using px’s own stem cells

Question 6

SHED

Answer 6

Stem cells from Human Exfoliated Deciduous teeth

Multipotent, capable of differentiating into neural cells, odontoblasts

Question 7

Teeth: a treasure chest of stem cells

Answer 7

Lots of different sources of stem cells in teeth/ around teeth

Question 8

Dental applications

Answer 8

Growing teeth?
Repair/ regeneration of dental tissue (clinical trials ongoing)
-pulp
-PDL
Craniomaxillofacial bone repair
-DPSC and craniofacial osteoblasts both derived from neural crest cells

Question 9

Cell types derived from dental stem cells

Answer 9

(A) cementoblast
(B) adiopocyte
(C) odontoblasts
(D) neuronal cells
(F) myoblast
(G) pulp cells
(H) hepatocyte
(I) endothelial cell
(J) osteoblast
(K) melanocyte

Question 10

Extra-oral applications in animals models so far

Answer 10

NS: SHED improves cognitive function in models of Alzheimer’s
Eyes: tissue engineered sheet of DPSC to reconstruct cornea
Muscles: SHED muscle regeneration in muscular dystrophy

Question 11

Problems with stem cells

Answer 11

Rejection/ immune reaction
Legal and ethical and political, embryonic stem cells and human cloning
Adult stem cells difficult to isolate and purify
May be the cells that produce cancer

Question 12

Regenerative medicine (dentistry)

Answer 12

Scaffold + cells + signals –> regeneration

Question 13

Gene therapy

Answer 13

A technique for correcting defective genes responsible for disease development
Normal gene inserted into genome to replace defective one
Vectors deliver gene to px’s target cells
Vectors commonly viruses (retro, adeno or adeno associated)

Question 14

Gendicine

Answer 14

First commercially available gene therapy 2003
Head and neck squamous cell carcinoma
p53 adenovirus
1 injection/ week for 8 weeks: 64% regression, 32% partial

Question 15

Salivary gland gene therapy

Answer 15

Encapsulated and accessible
Stable cell population which export large amounts of protein
Can be removed if there is a problem
Sjogren's syndrome/ Radiation damage
Could be used for systemic conditions

Question 16

Problems

Answer 16

Immune response/ virus vectors (Jesse Gelsinger 1999)
Gene therapy causes cancer: leukaemia in 2 children treated for X-SCID
Multi-gene disorders e.g. heart disease, most cancers not well suited to gene therapy
Short lived - integration of DNA into genome, rapidly dividing cells
Ethics & Regulation - germ cell therapy

Question 17

Gene editing

Answer 17

Precisely and efficiently modify DNA within a cell
Genome editing tools have 2 features:
-recognise specific DNA sequences (i.e. specific genes)
-cut DNA (nuclease)
Zinc finger nuclease, TAL effector nuclease, CRISPR associated nuclease
Editing can change the characteristics of a cell/ organism
Promise of permanent repair of the underlying disease-causing mutation

Question 18

CRISPR-Cas9

Answer 18

Clustered, Regularly Interspaced, Short Palindromic Repeat technology
An important new approach for generating RNA_guided nucleases, such as Cas9

Question 19

Gene editing: acute lymphoblastic anaemia

Answer 19

Genetically engineer donor immune cells to attack cancer
TALEN used to add CAR19 gene which will recognise CD19
Also disabled a receptor on donor cells that body would recognise as ‘foreign’

Question 20

Gene editing in embryos

Answer 20

Correction of a pathogenic gene mutation in human embryos

Question 21

Gene editing challenges

Answer 21

Technology in relatively early stage, needs to be further developed
Can enough cells be edited to have therapeutic impact?
Will editing be exquisitely specific, or will other regions of genome aside from target be affected?
‘Designer babies’!

Question 22

Screening/ diagnosis

Answer 22

Microarray analysis - gene chips
Expression of 61,000 genes analysed simultaneously & rapidly
Could use saliva
Identify pxs with
-disease (before symptoms)
-> risk of recurrence
-responders to therapy
-customise treatment