cell and molecular therapy Flashcards
What do we need new therapies?
Disability increases w age, population increasing in age
Most tissues have limited potential to regenerate
Advances in cell and molecular biology
Cost, effectiveness, public expectation
What are stem cells?
Undifferentiated cells (self-renewal) and grt one and often many cell types in body
Embryonic- pluripotent- any cell type
Adult- multi potent- limited no of cell types (bone marrow, most organs), can be persuaded to grt a few more cells
For 50 years- bone marrow transplants
How are teeth grown?
Permanent premolar tooth germ isolated from postnatal 30 day
Epithelial tissue and mesenchymal cell cross talk to form reconstituted tooth germ
Placed in organ culture for 2 days
Autologous transplantation into dogs mandible
If used in humans- use wisdom teeth to grow other types of teeth
However, elderly need and they often have these teeth removed
What is shed?
Stem cells from human exfoliated deciduous teeth
Also, teeth are a treasure chest of stem cells
What could be done w stem cells from oral cavity?
Grow teeth
Repair/regenerate dental tissue (pulp, PDL)
Craniomaxillofacial bone repair- dental pulp stem cells and craniofacial osteoblasts both derived from neural crest cells
What are cells types that could be derived from dental stem cells?
Cementoblast Pulp cells Endothelial cells Odontoblasts Osteoblasts Neuronal cells Myoblasts Chondrocytes Hepatocytes Melanocytes Adipocytes
What are problems with stem cells?
Rejection/immune reaction (need own)
Legal/ethical/political, esp embryonic stem cells and human cloning
Adult stem cells difficult to isolate and purify
May be the cells that produce cancer
What needs to be considered for tissue engineering?
Cells
Scaffold (3D matrix, natural/synthetic)
Signals (GFs, TFs etc to tell cells what to do in the environment)
What is gene therapy?
Corrects defective gene to treat disease
Vector delivers genes to target cells to insert into genome
Vectors (retro, adeno or adeno associated)
What is salivary gland gene therapy?
Encapsulated and accessible Stable cell population Exports large amounts of protein Can be removed if problem Could treat Sjögren’s syndrome/radiation damage Could be used for systemic conditions
What are problems with gene therapy?
Could have immune response to vectors or could cause cancer
Often multi gene disorders so multiple targets
Short lived therapy in rapidly dividing cells
Ethics and regulation- germ cell therapy
What is gene editing?
Efficiently/precisely modify DNA in cell
~recognise specific DNA sequences
~cut DNA (nuclease)
Enzymes that cut DNA- Zn finger nuclease, TAL effector nuclease, CRISPR associated nuclease
Editing can change characteristics of cell/organisms
Permanent repair to genome
What is CRISPR-Cas9?
Clustered regularly interspaced short palindromic repeat (recognises the DNA)
Cas9 (the enzyme)
What are challenges to gene editing?
Needs to be further developed
Can enough cells be edited to impact
Will other aspects of genome be indirectly affected
Designer babies? Worrying
What is screening/diagnosis via microarray analysis?
Looks at gene chips Expression of 61000 genes analysed simultaneously and rapidly Could use saliva Relatively cheap Could identify patients w- ~disease ~high risk of recurrence ~responders to therapy ~customise treatment
