4. Therapeutic Adult Stem Cells Flashcards
What is a stem cell?
Unspecialied cell capable:
Self rewnel
Proliferation
Differentiation into multiple linages
What is the potency heirachy?
Totipotency - (Zygote)
Pluripotent - (Inner cell mass)
Multipotent - (Neural SCs, Haematopoetic SCs)
Unipotent - (Commited progenitors, blood cells etc)
What are Adult Stem cells?
Stem cells of specific tissues
What do adult stem cells do?
Replenish different mature cell types
Where in the tissue are ASCs usually located and how often do they divide?
They are usually quiescent in the niche
Divide infrequently (Form one stem cell along with a rapidly cycling progenitor)
Progenitor forms cells of tissue
Adult stem cells are known for expressing plasticity, what does this mean?
They have the ability to cross over their identity from one organ to another
What two fields are ASCs used extensively in?
Cell therapy
Tissue engineering
What is the stem cell niche?
Specialized + restricted micoenvironment
Integrates signals
Maintains pool of quiescent stem cells
What are some extrinsic signals maintaining stem cells?
Local microenvironment
Soluble growth factors
Cell-ECM interaction
Mechanical factors
Cell-cell contact
Neural inputs
What are some intrinsic regulators of stem cell fate?
Instructive control
Selective Control
What is the process for extrinsive tissue formation?
- Increase in ECM turnover + thinning = stretch of tissue
- Stretched cells responsive to soluble growth factor and proliferate
- Increase in epithelial cell mass and new ECM causes bud formation
What is the difference between instructive and selective control?
What types of cells do Hematopoietic stem cells give rise to?
Myeloid (WBC, RBC, platelets)
Lymphoid
Where can you get Hematopietic stem cells from?
Bone marrow
Peripheral blood
Umbilical cord blood
Fetal tissues
What are the surface markers of HSCs in mice?
CD34low/-
SCA-1+
Thy1+ (low)
CD38+
C-kit+
lin-
What are the HSC surface markers in humans?
CD34+
CD59+
Thy1/CD90+
CD38low/-
C-kit/Cd117+
lin-
What are the clinical applications of HSC transplantation?
Autologous transplantation (self donation)
Allogenic Transplantation (recipients need immunosupressive meds, need to be HLA matched)
Treat hematopoietic + immune malignancies (replenish cells after high does chemo)
What are the two major advantages of HSC transplantation?
- No need to expand cells in culture
- No need to reconstitute multi-cellular tissue architecture prior to reimplantation
What are mesenchynal/stromal stem cells?
Non-hematopoietic cells residing in bonem arrow and other adult tissues
What lineages do mesenchyma stem cells differentiate into?
Mesoderm but can also have endodermic and neuroectodermic potential
Are MSCs a heterogenous population?
Yes
Can MSCs be expanded in vitro without loss of differentiation?
Yes
What markers are MSCs positive for?
CD29
CD44
CD54
CD71
CD73
CD90 (Thy1)
CD105
Cd106
CD271
GD2
Stro-1