Essentials of Stem Cell Biology

Robert Lanza, Anthony Atala, Robert Lanza, Anthony Atala

• Publisher: Academic Press
• Year: 2013
• ISBN:
  9780124104273
• Edition: 3
• Topic: Ciencias biológicas
• Subtopic: Biología celular

First developed as an accessible abridgement of the successful Handbook of Stem Cells, Essentials of Stem Cell Biology serves the needs of the evolving population of scientists, researchers, practitioners, and students embracing the latest advances in stem cells. Representing the combined effort of 7 editors and more than 200 scholars and scientists whose pioneering work has defined our understanding of stem cells, this book combines the prerequisites for a general understanding of adult and embryonic stem cells with a presentation by the world's experts of the latest research information about specific organ systems. From basic biology/mechanisms, early development, ectoderm, mesoderm, endoderm, and methods to the application of stem cells to specific human diseases, regulation and ethics, and patient perspectives, no topic in the field of stem cells is left uncovered.

• Contributions by Nobel Laureates and leading international investigators
• Includes two entirely new chapters devoted exclusively to induced pluripotent stem (iPS) cells written by the scientists who made the breakthrough
• Edited by a world-renowned author and researcher to present a complete story of stem cells in research, in application, and as the subject of political debate
• Presented in full color with a glossary, highlighted terms, and bibliographic entries replacing references

Part I

Introduction to Stem Cells

Outline

Chapter 1 Why Stem Cell Research? Advances in the Field

Chapter 2 ‘Stemness’

Chapter 3 Pluripotent Stem Cells from Vertebrate Embryos

Chapter 4 Embryonic Stem Cells in Perspective

Chapter 5 The Development of Epithelial Stem Cell Concepts

Chapter 1

Why Stem Cell Research? Advances in the Field

Alan Trounson, California Institute for Regenerative Medicine, San Francisco, CA, USA

Alan Trounson summarizes the major scientific discoveries that fueled the groundswell of knowledge from which today’s stem cell biology research emerged. Key people are noted as well as the organizations that are instrumental in supporting the fledgling stem cell industry.

Keywords

Origins of stem cell research; oocyte reprogramming; somatic cell reprogramming; human embryonic stem cell discovery; induction of pluripotent stem cells; International Society of Stem Cell Research; International Society for Cell Therapy; Alliance for Regenerative Medicine; California Institute for Regenerative Medicine

1.1 The Origins of Stem Cell Technology

Stem cell research, which aims to develop new cell therapies, has accelerated at an astonishing pace; both in terms of the breadth of interests and the discoveries that continue to evolve. Research in stem cell biology is opening new platforms to launch even more spectacular developments, crowding the pages of major journals each month. One might wonder why the field took so long to explode in such an incredible fashion.

The studies of John Gurdon and colleagues on reprogramming amphibian cells using oocytes stand as a very significant milestone that was emphatically amplified by Ian Wilmut and colleagues, who unexpectedly reprogrammed mammalian somatic cell nuclei into totipotent embryos when the nuclei were introduced into oocytes of the same species. Martin Evans and colleagues showed that cells isolated from the blastocyst stage of an embryo could be converted to pluripotent embryonic stem cells. Traveling on an independent plane of discovery were many great scientists, among whom Irv Weismann stands out for his discoveries of adult hematopoietic stem cells in mice and humans. Bone marrow transplants have a well-established history as a therapeutic strategy for cancer and other diseases of the blood.

What a melting pot of ingredients for James Thomson to launch the discovery of human embryonic stem cell lines, cloning for stem cells in the mouse by members of my own group, and most significantly the demonstration by Shinya Yamanaka of the ability to reprogram somatic cells to pluripotency (induced pluripotent stem cells) using four critical transcription factors. Again independently, Arthur Caplan isolated mesenchymal stem cells from bone marrow, showing their multipotent capacities to form bone, cartilage, and adipose tissue. Now we have the ingredients to explore the possibility of applying stem cell discoveries to regenerative medicine. The potential for using living cells to regenerate whole organs was quickly underscored by Anthony Atala’s demonstration of engineering bladders for patients.

1.2 Organizations that Advocate and Support the Growth of the Stem Cell Sector

Basic scientists gathered around Len Zon to form and launch the International Society of Stem Cell Research. Cell therapy and tissue transplant scientists have remained largely separate but have become another effective science and therapeutic organization under the International Society for Cell Therapy. Separately, the stem cell biotechnology industry has joined together under the umbrella of the Alliance for Regenerative Medicine to become an effective advocate for the emerging industry interests in cell and tissue therapies.

The Bush administration in the USA raised concerns within the fledgling stem cell science community by restricting the funding of embryonic stem cell research and limiting the number of embryonic stem cell lines that could be studied with federal funding. Key scientists in California coopted Robert Klein, a financier and lawyer, to their cause and he was able to galvanize the Californian voters to pass Proposition 71 (with 59% support) – a game-changing state bond initiative that required California to sell general obligation bonds up to $3 billion to fund pluripotent stem and progenitor cell research. This extremely clever approach to funding intellectual capital was supported by the Republican Governor Arnold Schwarzenegger, and established the Californian Institute for Regenerative Medicine (CIRM).

California has since become a major hub for stem cell research, attracting many of the world’s best scientists and rivaling the well-established biotechnology hubs around Boston and New York. Twelve new research institutes have been built in California under CIRM sponsorship, assembling a critical mass of intellectual excellence and driving an incredible productivity of discovery research. Both Thompson and Yamanaka have appointments in California institutions. Two clusters of biotechnology companies involved in cell therapies have evolved in the Bay Area and San Diego, with a third forming in Los Angeles. Companies are relocating to California and are actively opening offices and labs to contribute to the energized environment there. CIRM has also developed a very major network of collaborations with 12 international countries and states, a number of US states, foundations, and, most recently, with the US National Institutes of Health. These collaborations are driving globally a vast array of basic research and translational medicine, and changing the quality and depth of global research to find solutions to the world’s most feared and intractable diseases.

1.3 Applications of Stem Cells in Medicine

At the forefront of applying stem cell research are critical studies to find the means to eradicate the most dangerous cell of all – the malignancy seeding cancer stem cell in blood and solid tumors. There are also rapidly evolving strategies for curing HIV/AIDS, recovering sight from blindness, potentially curing Type I diabetes, using stem cells for delivering gene therapy, reversing spinal cord injuries, and curing other motor neuron and demyelinating diseases. The list of potential therapies is exhaustive and needs to be addressed as science opens an understanding of these diseases. Surprisingly, induced pluripotent stem (iPS) cell studies are exposing new insights into mental retardation, autism, epilepsy, and schizophrenia. Hope remains strong that cell therapies can offer substantial benefits to neurodegenerative conditions such as Parkinson’s, Alzheimer’s, and Huntington’s diseases.

Meanwhile the biotechnology industry has begun to deliver clinical trials using therapies derived from adult cells. The majority of trials are employing mesenchymal stem cells, adipose-derived stromal cells, and adult or fetal neural stem cells to evaluate safety and efficacy of cell-based therapies in indications ranging from disorders of soft tissue and bone to chronic conditions of heart disease, diabetes, and stroke. Adult cell-based therapies are even being evaluated for their ability to reverse or ameliorate genetic diseases.

Why would there not be a strong move of scientists towards stem cell research with the tools and critical technologies that have evolved? It appears that endogenous cell lineages may be manipulated by judicious use of tissue targeting of key transcription factors. Converting stromal phenotypes to endocrine, muscle, or neural cell types that have been lost in disease and injury could be the next major platform of stem and progenitor cell research. Could these developments sidestep the need to develop transplantation tolerance strategies for enabling effective grafting of allogeneic cellular therapies?

1.4 Challenges to the Use of Stem Cells

There remain very vocal and manipulative conservative and religious interest groups that decry the potential benefits of embryonic stem cell science, despite very strong overall community support in the US and elsewhere. They exclusively support adult stem cell therapies, including those where there is little scientific evidence of benefit and a lack of safety regulation. There is an important consideration that often fails in these commentaries that ignore science – do no harm.

Stem cell science will ultimately prevail despite the opposition from some quarters, because researchers will derive the evidence for understanding disease. By rigorous design and adequately controlled experimentation the true value of stem cell-based treatments will be demonstrated. If not, the hypotheses will fail and we will move on.

I wish I were starting again in stem cell research.

For Further Study

1. Atala A. Tissue engineering of human bladder. Br Med Bull. 2011;97:81–104.

2. Campbell KH, McWhir J, Ritchie WA, Wilmut I. Sheep cloned by nuclear transfer from a cultured cell line. Nature. 1996;380(6569):64–66.

3. Caplan AI. Mesenchymal stem cells. J Orthop Res. 1991;9(5):641–650.

4. Evans M. Embryonic stem cells: the mouse source – vehicle for mammalian genetics and beyond (Nobel Lecture). ChemBioChem. 2008;9(11):1690–1696.

5. Gurdon JB. Adult frogs derived from the nuclei of single somatic cells. Dev Biol. 1962;4:256–273.

6. Munsie MJ, Michalska AE, O’Brien CM, Trounson AO, Pera MF, Mountford PS. Isolation of pluripotent embryonic stem cells from reprogrammed adult mouse somatic cell nuclei. Curr Biol. 2000;10(16):989–992.

7. Spangrude GJ, Heimfeld S, Weissman IL. Purification and characterization of mouse hematopoietic stem cells. Science. 1988;241(4861):58–62.

8. Takahashi K, Tanabe K, Ohnuki M, et al. Induction of pluripotent stem cells from adult human fibroblasts by defined factors. Cell. 2007;131(5):861–872.

9. Thomson JA, Itskovitz-Eldor J, Shapiro SS, et al. Embryonic stem cell lines derived from human blastocysts. Science. 1998;282(5391):1145–1147.

10. Trounson A, Thakar RG, Lomax G, Gibbons D. Clinical trials for stem cell therapies. BMC Med. 2011;9:52.

Chapter 2

‘Stemness’

Definitions, Criteria, and Standards

Douglas Melton, Department of Molecular and Cellular Biology and Howard Hughes Medical Institute, Harvard University, Cambridge, MA, USA

Stem cells have generated more public and professional interest than almost any other topic in biology. One reason stem cells capture the imagination of so many is the hope that understanding their unique properties may reveal paths leading to new treatments for a variety of degenerative illnesses. And although the field of stem cell biology has grown rapidly, considerable confusion and disagreement as to the nature of stem cells exists. This confusion can be partly attributed to the sometimes idiosyncratic terms and definitions used to describe stem cells. Although definitions can be restrictive, they are useful when they provide a foundation for mutual understanding and experimental standardization. This chapter presents some definitions of stem cells, discusses the origin of stem cells, and suggests criteria or standards for identifying, isolating, and characterizing stem cells. Finally, the notion of ‘stemness’ and its possible application in understanding stem cell biology is explained.

Keywords

embryonic stem cells; adult stem cells; stemness; self-renewal; potency; lineage; differentiation potential; hematopoietic stem cells; neural stem cells

2.1 What is a Stem Cell?

Stem cells are functionally defined as having the capacity to self-renew and the ability to generate differentiated cells. More explicitly, stem cells can generate daughter cells identical to their mother (self-renewal), as well as produce progeny with more restricted potential (differentiated cells). Such a simple and broad definition may be satisfactory for embryonic or fetal stem cells that do not persist for the lifetime of an organism but it breaks down when trying to describe other types of stem cells (e.g., adult stem cells). Another functional parameter that should be included in a definition of stem cells is potency, or its potential to produce differentiated progeny. Does the stem cell generate multiple differentiated cell types (multipotent or pluripotent) or is it only capable of producing one type of differentiated cell (unipotent)? Thus, a more complete functional definition of a stem cell includes a description of its replication capacity and potency.

2.2 Self-Renewal

Stem cell literature is replete with terms such as ‘immortal,’ ‘unlimited,’ ‘continuous,’ to describe a cell’s replication capacity. These rather extreme and vague terms are not very helpful, as it can be noted that experiments designed to test the ‘immortality’ of a stem cell would by necessity outlast authors and readers alike. Such terms are probably best avoided or used sparingly.

Most somatic cells cultured in vitro display a finite number (less than 80) of population doublings prior to replicative arrest or senescence, in contrast to the seemingly unlimited proliferative capacity of stem cells cultured in vitro. Therefore, it is reasonable to say that a cell that can undergo more than twice this number of population doublings (i.e. 160) without oncogenic transformation can be termed ‘capable of extensive proliferation.’ In a few cases, this criterion has been met, most notably in embryonic stem (ES) cells derived from either humans or mice, as well as in adult neural stem cells (NSCs).

For adult stem cells, an incomplete understanding of the factors required for self-renewal ex vivo exists, thus the ability to establish similar proliferative criteria based on in vitro culture is limited. Therefore, the proliferative capacity of adult stem cells is currently best defined in vivo, where they should display sufficient proliferative capacity to last throughout the lifetime of the animal. In some cases, a rigorous assessment of the capacity for self-renewal of certain adult stem cells has been obtained by single cell or serial transfer into acceptable hosts, an excellent example of which is adult hematopoietic stem cells (HSCs).

2.3 Potency

The issue of potency may be the most difficult parameter to incorporate into a widely accepted definition of stem cells. A multipotent stem cell sits atop a lineage hierarchy and can generate multiple types of differentiated cells, the latter being cells with distinct morphologies and gene expression patterns. At the same time, many would argue that a self-renewing cell that can only produce one type of differentiated descendant is nonethel...