FFP1-Cellular Differentiation and Stem Cells PDF

Royal College of Surgeons in Ireland – Medical University of Bahrain FFP1-18 Cellular Differentiation & Stem Cells Module :FFP1 Code :FFP1 Class : MedYear1 semester 1 Lecturer : Dr Jeevan Shetty Date : 29th Sep 2024 Pre class Please watch these short videos 15-minute film, “A Stem C...

Royal College of Surgeons in Ireland – Medical University of Bahrain FFP1-18 Cellular Differentiation & Stem Cells Module :FFP1 Code :FFP1 Class : MedYear1 semester 1 Lecturer : Dr Jeevan Shetty Date : 29th Sep 2024 Pre class Please watch these short videos 15-minute film, “A Stem Cell Story” provides an excellent introduction to stem cells. See www.eurostemcell.org/films Video tutorials: – (Khan Academy): – https://www.youtube.com/watch?v=- yCIMk1x0Pk&ab_channel=KhanAcademy https://www.youtube.com/watch? v=uUH5YI5dTOg&ab_channel=khanacademymedicine 2 Learning Objectives 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. Compare and contrast the types of stem cells. 5. Describe the potential applications of stem cells. 6. Discuss the ethical issues surrounding stem  Human zygote Development… 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. zygote 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 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. 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 8 cell are different from other cells of the Stem cell Stem cell 1. SELF-RENEWAL 2. (copying) DIFFERENTIATI ON (specializing) specialized cell Identical stem cells -e.g. muscle cell, nerve cell - cannot divide to make Self renewal - copies Differentiation of themselves - replaces dead or dama maintains the stem cells throughout your life  Maintain the pool of stem cells STEM CELLS Self-renewal Undifferentiat ed cells that divide and Differentiation give rise to cells that differentiate into specialized Replacing Developme cells damaged nt of cells embryo  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 lif 1. embryonic stem cells blastocyst - a very early embryo 3. induced pluripotent stem cells haematopoietic (blood) stem cells umbilical cord blood  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  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 ns A skin io c ondit under grow grow under con ditions B neuro grow und ns embryonic stem cells er c ond gro i ti o n w sC un de blood rc on dit ion sD live r ? Controls not 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: MULTIPOTENT red blood cells, white blood cells, 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 - higher potency committed - rare progenitors: specialized - “transient amplifying cells: cells” - work - multipotent - no division - divide rapidly - no self-renewal  Tissue stem cell examples: 1. Haematopoietic stem cells (HSCs) NK cell T cell B cell dendritic cell megakaryocyteplatelet s HSC erythrocytes macrophage neutrophil bone marrow eosinophil basophil committed specialized progenitors cells  Tissue stem cell examples: 2. Mesenchymal stem cells (MSCs) Bone (osteoblasts) MSC Cartilage (chondrocytes) bone marrow Fat (adipocytes) committed specialized cells progenitors  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 Shinya Yamanaka and John Gurdon- 2012 Nobel differentiation culture iPS cells in the lab all possible types of vantage: No need for embryos specialized cells Genetically identical advantages: 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 Number of different processes used to produce genetically identical copies of a biological entity. 27  Cloning There are three VERY different types of cloning: Reproductive cloning Therapeutic Molecular cloning cloning gene 1 gene 2 Live birth cloning. DNA cloning. Use to make two identical Experimental cloning. Use to study what a gene individuals Use to make patient- does specific cell lines Very difficult to do isolated from an Routine in the biology lab embryo (not intended Illegal to do on humansfor transfer in utero)  Reproductive cloning adult cell egg take the cell remove nucleus (containing DNA) and take the rest of the cell How many Clone attempts? identical to the individual that gave the nucleus Dolly the sheep Somatic-Cell Transfer (SCT) laboratory technique for creating a cloned 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. 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 Is a human embryo equivalent to a human Does a human at fertilization, embryo have in the womb, or child? any rights? at birth? Might the destruction of a With iPS cells now single embryo be justified available as an Since ES cells can if it provides a cure for a alternative to hES grow indefinitely in a countless number of cells, is the debate dish and can, in theory, patients? over stem cell still grow into a human being, is the embryo research irrelevant? Should the laws that really destroyed? govern iPS cells differ from those for hES iPS cells have the Since iPS cells are not cells? If so, what potential to develop exactly the same as hESlegislation is needed? into a human cells, and hES cells still embryo, in effect provide important controls, producing a clone of should hES research 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): – https://www.youtube.com/watch?v=- yCIMk1x0Pk&ab_channel=KhanAcademy https://www.youtube.com/watch? v=uUH5YI5dTOg&ab_channel=khanacademymedicine 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. Post session Knowledge Check (fill the boxes) Name 3 types 1. 2. 3. of 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 cell mass of a umbilical and reprogramming blastocyst throughout involving the 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 patient. informed consent. matched to patient. No major ethical concerns.