Pluripotent Stem Cells Flashcards
What are stem cells?
Cells with the ability to self-renew and differentiate into specialised cell types.
What are the main types of stem cells based on potency?
Totipotent, pluripotent, multipotent, and unipotent.
What are pluripotent stem cells?
Cells that can differentiate into any cell type from the three germ layers but cannot form extraembryonic tissues.
What are embryonic stem cells (ESCs)?
Pluripotent cells derived from the inner cell mass of the blastocyst.
What are induced pluripotent stem cells (iPSCs)?
Reprogrammed somatic cells that gain pluripotency through specific transcription factors.
Who discovered iPSCs and when?
Shinya Yamanaka in 2006.
What are the four Yamanaka factors used for iPSC generation?
Oct4, Sox2, Klf4, and c-Myc.
What are the main applications of iPSCs?
Disease modelling, drug screening, and regenerative medicine.
What is hematopoiesis?
The process of blood cell formation from hematopoietic stem cells.
Where does hematopoiesis occur in the embryo?
First in the yolk sac, then in the aorta-gonad-mesonephros (AGM) region, and later in the bone marrow.
What is the difference between primitive and definitive hematopoiesis?
Primitive hematopoiesis occurs early in development and produces mainly red blood cells, while definitive hematopoiesis generates all blood cell types.
What are embryoid bodies (EBs)?
3D aggregates of pluripotent stem cells that mimic early embryonic development.
What are organoids?
Miniature, 3D self-organised structures derived from stem cells that resemble an organ.
What are the three germ layers formed during differentiation?
Ectoderm, mesoderm, and endoderm.
What is the role of the extracellular matrix (ECM) in stem cell differentiation?
It provides structural and biochemical signals that guide differentiation.
What are the ethical concerns regarding embryonic stem cells?
They require the destruction of embryos, raising moral and legal debates.
How do hESCs maintain their pluripotency?
Through the expression of key transcription factors like Oct4, Sox2, and Nanog.
What are the main differentiation pathways of mesoderm-derived cells?
Cardiomyocytes, hematopoietic cells, and bone-forming cells.
What is the significance of neural crest cells in fetal stem cell biology?
They contribute to multiple tissues, including neurons, glia, and facial structures.
What are the challenges in using iPSCs for therapy?
Low efficiency of reprogramming, risk of genetic mutations, and potential immune rejection.
What is self-renewal in stem cells?
The ability of a stem cell to divide and produce identical daughter cells while maintaining its undifferentiated state.
What is the difference between totipotent and pluripotent cells?
Totipotent cells can develop into all cell types, including extraembryonic tissues, while pluripotent cells can develop into any cell type but not extraembryonic tissues.
What is the role of Waddington’s landscape model in stem cell biology?
It represents cell fate as a ball rolling down a hill, illustrating how differentiation is typically unidirectional.
What is somatic nuclear transfer (SCNT)?
A technique where the nucleus of a somatic cell is transferred into an enucleated egg cell to generate a cloned embryo.
What are the major signalling pathways involved in ESC maintenance?
LIF/STAT3, BMP, and WNT pathways.
What are the key features of ESC culture?
ESCs require a feeder layer or defined extracellular matrix, specific growth factors, and low oxygen conditions.
What is the main limitation of using viral vectors for iPSC reprogramming?
The risk of insertional mutagenesis and potential tumorigenicity.
What are non-integrative methods for iPSC generation?
Sendai virus, episomal vectors, mRNA transfection, and protein-based methods.
What is the function of telomerase in stem cells?
It maintains telomere length, enabling prolonged self-renewal and preventing cellular senescence.
Why do hESCs form teratomas in vivo?
Because they are pluripotent and can differentiate into all three germ layer-derived tissues.
What is epigenetic memory in iPSCs?
Residual DNA methylation and histone modifications from the original somatic cell that may influence differentiation potential.
What are the main challenges of differentiating iPSCs into functional β-cells for diabetes therapy?
Achieving full maturation, glucose responsiveness, and avoiding immune rejection.
What are the key applications of organoids derived from pluripotent stem cells?
Disease modelling, drug testing, and regenerative medicine.
What are the advantages of using 3D organoid cultures over 2D cell cultures?
They better mimic in vivo tissue architecture and cellular interactions.
What is the role of Notch signalling in hematopoiesis?
It regulates hematopoietic stem cell maintenance and differentiation.
What are the three waves of hematopoiesis during development?
Primitive (yolk sac-derived), transient definitive (fetal liver), and definitive hematopoiesis (bone marrow).
What is the significance of the hemogenic endothelium?
It serves as the precursor for hematopoietic stem cells (HSCs) in the embryo.
What are the major cytokines involved in hematopoiesis?
Erythropoietin (EPO), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukins (IL-3, IL-6).
What are CFU assays used for in hematopoietic research?
To assess the differentiation potential of hematopoietic progenitors in vitro.
What is the major ethical concern regarding therapeutic cloning?
It involves creating and destroying human embryos to derive stem cells.
What is the difference between ESC-derived cardiomyocytes and native heart cells?
ESC-derived cardiomyocytes often lack full electrophysiological maturity and contractile function.
What are embryonic germ cells (EGCs)?
Pluripotent cells derived from the primordial germ cells of a fetus.
What is teratoma formation a test for?
Pluripotency, as stem cells injected into immunodeficient mice form tumors containing all three germ layers.
What are induced neural stem cells (iNSCs)?
Somatic cells reprogrammed to neural stem cells without passing through a pluripotent state.
What are pericytes?
Cells that wrap around endothelial cells in capillaries and venules and may have stem cell-like properties.
What is cellular reprogramming?
The process of converting one cell type into another by altering gene expression.
What is an example of a direct lineage conversion?
Fibroblasts being converted into neurons without becoming pluripotent.
What are hematopoietic stem cells (HSCs)?
Stem cells that give rise to all blood cell types and are found in the bone marrow.
What are the main markers of hematopoietic stem cells?
CD34+, CD133+, and c-Kit+.
What is the hematopoietic niche?
A specialized microenvironment in the bone marrow that supports HSC maintenance and differentiation.
What is the difference between myeloid and lymphoid progenitors?
Myeloid progenitors give rise to red blood cells, platelets, and granulocytes, while lymphoid progenitors produce B cells, T cells, and NK cells.
What are common differentiation pathways of mesodermal cells?
They can become cardiomyocytes, endothelial cells, hematopoietic cells, or bone-forming osteoblasts.
What are satellite cells?
Muscle stem cells responsible for muscle repair and regeneration.
What is the function of Sox2 in stem cells?
A transcription factor critical for maintaining pluripotency in ESCs and iPSCs.
How do growth factors influence stem cell differentiation?
They regulate cell fate by activating specific signalling pathways like Wnt, BMP, and FGF.
What are the main applications of neural stem cells?
They can be used to treat neurodegenerative diseases, spinal cord injuries, and brain injuries.
What are cardiomyocytes?
Heart muscle cells responsible for contraction and pumping blood.
Why is vascularization important in stem cell therapy?
It ensures sufficient oxygen and nutrient supply for transplanted cells.
What is the significance of bone marrow transplantation?
It is a form of stem cell therapy used to treat blood disorders such as leukemia.
What is paracrine signalling in stem cells?
A way in which stem cells influence neighbouring cells by secreting signalling molecules.
How does hypoxia affect stem cells?
Low oxygen levels maintain stem cell self-renewal and pluripotency by activating HIF-1.
What are the risks of stem cell therapy?
Tumor formation, immune rejection, and improper differentiation.
What are hematopoietic stem cell transplants used for?
To treat leukemia, lymphoma, and other blood-related diseases.
What is somatic cell nuclear transfer (SCNT) used for?
To create cloned embryos and derive patient-specific ESCs.
What is the difference between autologous and allogeneic stem cell transplants?
Autologous transplants use the patient’s own cells, while allogeneic transplants use donor cells.
What is the role of extracellular vesicles in stem cell biology?
They mediate cell communication and can influence regeneration.
How do scaffold materials aid in tissue engineering?
They provide structural support and biochemical cues for cell attachment and differentiation.
What is cell-based gene therapy?
The use of genetically modified stem cells to treat diseases by replacing defective genes.
What is an example of a disease model using iPSCs?
iPSCs from ALS patients can be used to study motor neuron degeneration.
What are clinical-grade iPSCs?
iPSCs that meet regulatory standards for use in human therapies.
What is a blastoid?
A blastocyst-like structure generated solely from stem cells.
What is the main goal of bioengineering in regenerative medicine?
To create functional tissues and organs for transplantation.
