RCSI Year 1 FFP Cellular Differentiation & Stem Cells 2024 PDF

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Cellular Differentiation & Stem Cells Module FFP1 Lecture Cellular Differentiation & Stem Cells Lecturer Prof Maria Morgan ([email protected]) Date Oct 2024  LEARNING OUTCOMES 1. Define cellular...

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Cellular Differentiation & Stem Cells Module FFP1 Lecture Cellular Differentiation & Stem Cells Lecturer Prof Maria Morgan ([email protected]) Date Oct 2024  LEARNING OUTCOMES 1. Define cellular differentiation. 2. Define the unique properties of stem cells. 3. Describe the different sources of stem cells including embryonic, tissue and induced pluripotent (iPS) stem cells. 4. Describe the potential applications of stem cells. 5. Discuss the ethical issues surrounding stem cell use.  Human Development… zygote inner cell mass (ICM) morula trophectoderm blastocyst embryo fetus 8th week See also Anatomy lectures 3 FUNDAMENTAL ASPECTS OF DEVELOPMENTAL BIOLOGY 1. Cell division Growth of cell populations, where one cell grows and divides to produce two ‘daughter cells’. 2. Cell differentiation Process by which a less specialized cell becomes a more specialized cell type. 3. Morphogenesis Process controls the organized spatial distribution of cells  CELLULAR DIFFERENTIATION Complex organism requires many different cell types to form structures and carry out specific functions. If all the cells arise from a single fertilised egg cell and all contain the same DNA in their nuclei, how do they become different to each other or ‘differentiate’? This is what we call cellular differentiation. CONTROL OF CELLULAR DIFFERENTIATION By differential gene expression: cells become different because they express different genes. Same DNA if cells from one individual  express myosin genes  express globin gene X express globin gene X express myosin genes Different cell types follow different differentiation programmes. Differentiation is a common process in adults as well: adult stem cells divide and create fully differentiated daughter cells during tissue repair and normal cell turnover. Stem cell biology basics 7 Stem cell are different from other cells of the body Stem cell Stem cell 1. SELF-RENEWAL 2. DIFFERENTIATION (copying) (specializing) specialized cell Identical stem cells -e.g. muscle cell, nerve cell - cannot divide to make copies of themselves Self renewal - maintains Differentiation - replaces dead or damaged the stem cell pool cells throughout your life  STEM CELLS Self-renewal Undifferentiated cells that divide and give rise to cells that Differentiation differentiate into specialized cells  Stem cell niches Niche stem cell Microenvironment around stem cells that provides support and signals regulating self-renewal and differentiation niche Direct contact Soluble factors Intermediate cell  Where are stem cells found? 2. tissue stem cells fetus, baby and throughout life 1. embryonic stem cells blastocyst - a very early embryo 3. induced pluripotent stem cells  Stem cell Terms Potency: A measure of how many types of specialized cell a stem cell can make Multipotent Can make multiple types of specialized cells, but not all types Tissue stem cells are multipotent Pluripotent Can make all types of specialized cells in the body Lack potential to (extensively) contribute to extraembryonic tissue, such as the placenta Embryonic stem cells from ICM are pluripotent Totipotent Can make all types of cells in the body PLUS cells that are needed during development of the embryo only: placenta, umbilical cord Early embryonic stem cells (8 cell stage embryo, morula) are totipotent  Types of stem cell: 1) Embryonic stem cells  Embryonic stem (ES) cells: Where we find them blastocyst cells inside = ‘inner cell mass’ fluid with nutrients culture in the lab embryonic stem cells taken from to grow more cells the inner cell mass outer layer of cells = ‘trophectoderm’  Embryonic stem (ES) cells: What they can do differentiation embryonic stem cells PLURIPOTENT all possible types of specialized cells  Embryonic stem (ES) cells: Challenges skin neurons embryonic stem cells blood ? liver Types of stem cell: 2) Tissue stem cells  Tissue stem cells: Where we find them surface of the eye brain skin breast testicles intestines (gut) bone marrow muscles  Tissue stem cells: What they can do blood stem cell differentiation found in bone marrow only specialized types of blood cell: red blood cells, white blood cells, MULTIPOTENT platelets Tissue stem cells can ONLY make the kinds of cell found in the tissue they belong to.  Tissue stem cells: Principles of renewing tissues Stem cell stem cell: - self renew* - divide rarely committed progenitors: - higher potency (compared -to progenitor cells) - “transient amplifying cells” specialized cells: - rare - multipotent - work - divide rapidly - no division - no self-renewal *Self-renewal is division with maintenance of the undifferentiated state.  Tissue stem cell examples: 1. Haematopoietic stem cells (HSCs) NK cell T cell B cell dendritic cell megakaryocyte platelets HSC erythrocytes macrophage neutrophil bone marrow eosinophil basophil committed progenitors specialized cells  Tissue stem cell examples: 2. Mesenchymal stem cells (MSCs) Bone (osteoblasts) MSC Cartilage (chondrocytes) bone marrow Fat (adipocytes) committed progenitors specialized cells  Types of stem cell: 3)Induced pluripotent (iPS) stem cells  Induced pluripotent stem cells (iPS cells) ‘genetic reprogramming’ = add certain genes to the cell adult cell induced pluripotent stem (iPS) cell behaves like an embryonic stem cell differentiation culture iPS cells in the lab all possible types of Advantage: No need for embryos specialized cells Genetically identical Disadvantages: Large numbers of somatic cells needed Long term studies still required.  Induced pluripotent stem cells (iPS cells) genetic reprogramming adult cell (skin) Oct4, Sox2, Klf4 and c-Myc pluripotent stem cell (iPS) differentiation http://www.youtube.com/watch?v=cPvidAvzmx0&feature=player_embedded http://www.youtube.com/watch?v=i-QSurQWZo0&feature=related Cloning 26  Cloning There are three VERY different types of cloning: Reproductive cloning Therapeutic cloning Molecular cloning gene 1 gene 2 Live birth cloning. Experimental cloning. DNA cloning. Use to make two identical Use to make patient- Use to study what a gene does individuals specific cell lines isolated from an embryo (not Routine in the biology labs Very difficult to do intended for transfer in utero) Illegal to do on humans  Reproductive cloning adult cell egg take the cell remove nucleus (containing DNA) and take the rest of the cell Clone identical to the individual that gave the nucleus Dolly the sheep SOMATIC-CELL TRANSFER (SCT) laboratory technique for creating a clone embryo with a donor nucleus  THERAPEUTIC CLONING Definition: Transfer of nuclear material from a somatic cell into an enucleated oocyte in the goal of deriving embryonic cell lines with the same genome as the nuclear donor. Little to no risk of rejecting transplanted cells/tissues - immunologically compatible with patient. ? SCT in human cells ? - ethical concerns(egg procurement) & technical challenges  APPLICATIONS OF STEM CELLS Regenerative Medicine – Potential to treat diseases by replacing cells which are irreversibly lost, and for which there are currently no therapies, – E.g. Parkinson’s, heart disease, diabetes, spinal cord injury… – Bone marrow transplants and skin grafting are established examples of therapeutic use of stem cells. Drug testing and screening - stem cells directed to produce a specific cell type in lab, huge amounts of identical cells. At the early stages of candidate drug testing scientists need large number of cells to carry out assays in vitro and replicate their experiments multiple times so they need large numbers of identical cells. Study disease processes - most cases its extremely difficult to obtain cells damaged due to the disease in order to study them in detail – diseased cells used to model the disease. STEM CELL SUCCESS STORIES?  REGULATION OF STEM CELL RESEARCH Legislation regarding use of ES cells varies around the globe. Many countries (US, UK, Australia), new cell lines can be created from spare embryos from fertility clinics with consent from donors. Laws prohibit the creation of embryos for research. Ireland - one of few countries in Europe that has no regulation for stem cell research. Link to regulations in other European countries: http://www.eurostemcell.org/stem-cell-regulations  STEM CELL RESEARCH RAISES MANY QUESTIONS: Does life begin Does a human at fertilization, in Is a human embryo equivalent to a human embryo have the womb, or at any rights? birth? child? Might the destruction of a With iPS cells now single embryo be justified if available as an Since ES cells can grow it provides a cure for a alternative to hES indefinitely in a dish and countless number of cells, is the debate can, in theory, still grow patients? over stem cell into a human being, is the embryo really research irrelevant? Should the laws that destroyed? govern iPS cells differ from those for hES cells? If so, what iPS cells have the legislation is needed? potential to develop into Since iPS cells are not exactly the same as a human embryo, in hES cells, and hES cells still provide effect producing a clone important controls, should hES research of the donor – is this continue? ethical? KEY POINTS Cellular differentiation: cells become different (specialized) because they express different genes Stem cells – 2 properties – Self renewal – Differentiation Types of stem cells – Embryonic stem cells (pluripotent) – Tissue stem cells (multipotent) – Induced pluripotent stem cells Somatic-Cell Transfer (SCT) – Reproductive cloning – Therapeutic cloning  FURTHER INFORMATION AND RESOURCES 15-minute film, “A Stem Cell Story” provides an excellent introduction to stem cells. See www.eurostemcell.org/films Video tutorials: – (Khan Academy): http://www.youtube.com/watch?v=-yCIMk1x0Pk – http://learn.genetics.utah.edu/content/tech/stemcells/scintro/ Acknowledgements EuroStem Cell Slides (selected slides) - Dr Christele Gonneau, Freddy Radtke of EPFL, Switzerland, Keisuke Kaji, University of Edinburgh, UK, Jonas Larsson, Lund University, Sweden, Hans Clevers and Nick Barker, Hubrecht Institute.  KNOWLEDGE CHECK (FILL THE BOXES) Name 3 types of 1. 2. 3. stem cells Sources Potency Ethical concerns /limitations  KNOWLEDGE CHECK (ANSWERS) 3 types of stem Embryonic Tissue Induced pluripotent cells Sources Cells from the inner Fetus, baby, Genetic reprogramming cell mass of a umbilical and involving the blastocyst throughout introduction of 4 transcription factors (Oct4, Sox2, Klf4 and c- Myc) to a somatic cell Potency Pluripotent Multipotent Pluripotent Ethical concerns Requires Difficult to identify, Long term effects /limitations destruction of isolate & maintain unknown. embryo. in lab. Stem cells could be Stem cells can be genetically matched to Donation requires genetically matched patient. informed consent. to patient. No major ethical concerns.  YEAR 1 STUDENTS IN NEED OF ASSISTANCE RCSI Student Assistance Programme – If you need urgent emotional support contact our student assistance programme available 24/7/ 365. This service provides counselling free of charge to our students: Freephone: 1800 851 340 International: 00353 1 518 0277 WhatsApp: Text 'Hi' to 087 369 0010 RCSI Centre for Mastery: Personal, Professional & Academic Success (CoMPPAS) – A multidisciplinary team of RCSI professionals and specialists working collaboratively to empower students to achieve their academic, personal and professional goals: – Moodle page: https://vle.rcsi.com/course/view.php?id=2583 General Queries: [email protected] Career Development: [email protected] Academic Development: [email protected] Learning Support (Disability) : [email protected] Student Welfare : [email protected] Niteline: 1800 793 793 (Instant messaging on https://niteline.ie 9pm-2.30am every night of term). Late-night listening, support and information service run by students for students in the greater Dublin area. RCSI Security Emergency Contact (+353) 01-402219 : – If require urgent assistance from RCSI, or you are on campus you can contact security at 01 402 22 19. This number will not result in an in person response. Please note that in an emergency your safest action is to contact the local emergency services (112/999). If you are an International Student you should also contact your Embassy/ Sponsor to advise them of your circumstances. Mercers Medical Centre (General Practice) for health/COVID advice: – https://www.mercersmedicalcentre.com/rcsi-students For urgent medical advice/emergency outside regular hours contact DubDoc (Out of Hours GP) (+353) 01- 4545607 https://www.dubdoc.ie/ – DubDoc provides urgent medical care to patients that cannot wait to be seen by their usual GP. Emergency Services dial 999/112.