Stem Cells Flashcards
Totipotent
Can become any cell in body or placenta
Pluripotent
Can become any cell in body
Multipotent:
Can become any cell within a specific germ layer or cell lineage
Steps of cell fate
Fertilised egg > totipotent stem cell > FATE decision
Embryonic stem cells
- Pluripotent
- From embryonic tissues
- Not committed to a specific fate
- Self-renewing
Adult Stem Cells
- Multipotent
- From adult tissues
- Limited resource/difficult access
- Limited renewal
Induced Pluripotent Stem Cells
- Pluripotent
- From adult peripheral tissue
- Genetically manipulated e.g fibroblast
- Self-renewing, but not for indefinite time
Original protocol
- Retroviral transduction
- Introducing pluripotent TFs
- Major rearrangement of epigenome
- Differentiation into cell type
- Clear fibroblast for hard wired info
What processes are requires for cells do go from fibroblast to neurons and glia ??
+ Transcription factors or miRNAs
SDR
What processes are required to go from fibroblast to iPSCS?/
Fribroblasts > + transient pluripotency factors expression ( epigenetic actviation)
> unstable intermediates > continued expression of pluripotency factors > iPSCs
Unstable intermediates
Unstable intermediates - 2 pathways
PDR> + neuralising condition to a neural progenitor
OR
Continued expression of pluripotency factors > iPSCs
Cheaper and faster alternatives
Fibroblast straight to neurons and glia
IPSCs
Large quantities
Fibroblast to Neuron
one shot
iPSC reprogramming
Rejuventation
old and young fibroblasts to iPSCc motor neuron
Direct Reprogramming
Ageing maintenance
YOung and old fibroblast»_space; young Fib-iMN and Old Fib -iMN
IPSC-
wiped out epigenome
Mimic embryonic stage > result sc are embryonic like
Issue when studying neurodegeneration> often in older population
What is the key difference between direct and iPSPC reprogramming ?
Direct allows preservation of some of the ageing features
Potential for Stem cells
• Exploring disease mechanisms
– Study how basic cellular mechanisms are disrupted in disease
• Drug discovery
– High-throughput assays will identify targets. For example, using hSC cell-derived neural cells for an assay to screen drugs for Alzheimer’s disease
• Toxicology testing
- Identify environmental toxins
ALS
ALS is one of the most common adult onset motor disorders, characterised by progressive degeneration of upper and lower MNs
ALS mutations response for 60%of familial cases
SOD1, TARDBP, FUS and C9ORF72
Difference between clinical ALS and Familial ?
clinically undistinguishable
- no in vitro model only a cellular model
Astrocytes
Astrocytes- support MN metabolic processes and GFs
- neural support cell
Drug discovery protocol in ALS patients -
- skin biopsy of ALs patient
2 - Donor fibroblast culture - iNPCs - cellular programming with reprogramming genes
- Neural cell aggregates
- MN and astrocytes in culture
- Robotic drug screening - test one chemical compound per well ** identify therapeutic compounds and disease mechanisms**
MS Demyelinating disorder - Drug discovery
Oligodendrocyte precursor cells in a well with test compunds
- pre myelinatiing oligodendrocyte
- fix and anti MBP immunostain
- automated image acquisition and quantification
***
- treated with 727 drugs
stained for myelin
looked for compounds promoting myelin - 34
Drug screening in AD
- made patient cortical Neurons
- ipsc - based trial for mutiple individuals
- iPscs
- patient cortical neurons
- pharmaceutical compound library
- chemical structure- based clustering and combination analysis
- Anti-ab cocktail
- iPscs
Stem cell transplants in AD patients
- Provide injured area with trophic factors
- Induce activation and proliferation of endogenous neural stem cells
- Partial cell replacement
