Helen Blau | |
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Born | Helen Margaret Blau London, England |
Nationality |
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Other names | Helen M Blau |
Alma mater | |
Spouse | David Spiegel |
Children | 2 |
Family | Eve Blau (sister) |
Scientific career | |
Fields | Developmental biology, Regenerative medicine, Stem cell biology |
Institutions | Stanford University Medical School |
Website | Blau Lab website |
Helen Blau FRS is a cell biologist and stem cell researcher famous for her work on muscle diseases, regeneration and aging. She is the Donald E. and Delia B. Baxter Foundation Professor and the Director of the Baxter Laboratory for Stem Cell Biology at Stanford University. [1] Blau is known for overturning the prevailing view that once a cell assumes a certain specialty in the body — or differentiated state —such as a skin or liver cell, it cannot be changed. Her research established that the fate of mammalian cells can be altered. [2] [3] [4] [5] Her finding that specialized cells can be triggered to turn on genetic programs characteristic of other differentiated states provided early evidence that mammalian cellular reprogramming was possible and opened the door to the use of reprogramming in stem cell biology. [6] Her work set the stage for the development of induced pluripotent stem cells and associated stem cell therapies. [7]
Blau is also known internationally for her work on adult stem cells and how they maintain, repair and rejuvenate tissues, in particular muscle. [8] [9] [10] [11] [12] She revealed the role of the microenvironment of the niche, most notably tissue stiffness, in regulating stem cell function and showed how stem cell function declines in aging and hereditary muscle wasting diseases. She discovered ways to rejuvenate aged stem cell function. Blau discovered a new class of aging-associated enzyme she termed a “gerozyme” and showed that pharmacological targeting of the gerozyme in aged muscle tissue can rejuvenate tissue structure and metabolism and increase strength. [13] [14]
Blau was born in London and is a dual citizen of the United States and Great Britain. She earned a B.A. from the University of York in England and an M.A. and Ph.D. in biology from Harvard University with Fotis C. Kafatos.
After a postdoctoral fellowship with Charles J. Epstein in the departments of Biochemistry and Biophysics and the Division of Medical Genetics at The University of California, San Francisco (UCSF), she joined the faculty at Stanford University in 1978. She was awarded an endowed chair in 1999 and named Director of the Baxter Laboratory for Stem Cell Biology in 2002. She is married to David Spiegel, also a Professor at Stanford. They have two children, Daniel Blau Spiegel and Julia Blau Spiegel.
It was long thought that the differentiated state is fixed and irreversible. In the 1980s, Blau challenged that idea using a cell fusion system she devised to join cells of two different species and differentiated states. Her experiments showed that previously silent genes could be activated. [2] [3] [4] [5] Specifically, when human skin, connective tissue, or liver cells were fused with mouse muscle cells, the human cells began to make muscle-specific gene products. This body of work showed that the differentiated state requires continuous reinforcement, and that a shift in the balance of regulator proteins called transcription factors in the nucleus can reprogram the cell to become a different type of cell. [6] [15] [16] This discovery of an unexpected plasticity, or flexibility, in cell fate was foundational for the development of the field of stem cell biology and regenerative medicine. It was featured as “Plasticity of the Differentiated State” on the cover of the Frontiers in Biology special issue of the journal Science in 1985. [17]
Adult stem cells are found in tissues throughout the body. When they divide during development, or to repair damage after injury, one daughter cell remains a stem cell (it self-renews), while the other differentiates (it specializes) to become one of the cell types that make up that tissue.
In 2008, Blau published the first parameters for isolating muscle stem cells, also known as satellite cells, using flow cytometry. Her lab pioneered the use of bioluminescence imaging to monitor the dynamics of muscle stem cell engraftment in muscles in live mice and confirmed that the cells were true stem cells, capable of both self-renewal and differentiation. [8] They also designed a bioengineered hydrogel with a stiffness that mimics healthy young muscle. Unlike rigid plastic tissue culture dishes, the elastic hydrogel preserves the stemness of the cells when grown in culture. [9] [18] [19] This discovery provided the first functional link between substrate elasticity and the maintenance of stem cell self-renewal properties and established a paradigm with broad utility to enhance the regenerative capacity of tissue-specific stem cells grown in the laboratory.
In 2014 Blau’s lab provided early evidence that stem cell function declines during aging due to internal defects, in addition to external factors. [10] They identified a small molecule, SB202, that inhibits an enzyme associated with aging called p38-MAP kinase and showed that the regenerative properties of aged muscle stem cells could be rejuvenated through a combination of biophysical (growth on the bioengineered hydrogels Blau’s lab designed) and biochemical (blocking p38MAPK) signals. [20] More recently, Blau showed that muscle stem cells exhibit an age-dependent increase in CD47 levels, and that this increase is a hallmark of age-related muscle stem cell dysfunction. [12] CD47 is a protein found on the surface of many cells in the body that protects them from attack by the body’s immune system; an increase in the number of CD47 molecules on old or diseased cells can prevent the body from disposing of them properly. Overcoming this increase in CD47 levels led to a robust increase in muscle strength after injury. [12] These approaches provide a paradigm for cell therapy strategies to treat muscle wasting.
In 2017 Blau’s lab identified prostaglandin E2 (PGE2) as a critical component of the inflammatory response that orchestrates the natural muscle repair process. They showed that blocking the ability of muscle stem cells to respond to PGE2, or treatment with non-steroidal anti-inflammatory drugs like ibuprofen that inhibit PGE2 synthesis, leads to loss of muscle strength after injury. [11] Injection of PGE2 into injured muscles causes resident muscle stem cells to increase in number and enhances muscle repair. [11] These experiments showed that PGE2 is required and sufficient for muscle stem cell function in recovery after injury.
In 2021 Blau discovered that with aging muscles accumulate increasing amounts of the enzyme 15-PGDH, the prostaglandin degrading enzyme which breaks down PGE2. [13] This enzyme appears to be a master regulator of muscle aging. If 15-PGDH is overexpressed in muscles of young mice, they exhibit muscle atrophy and weakness that mimic the effect of years of aging. Conversely, using a small molecule drug to reduce the activity of 15-PGDH in old mice markedly increases muscle mass, strength and endurance when running on a treadmill. [13] These experiments showed that 15-PDGH is a pivotal molecular determinant of aging in muscle — a new class of molecule Blau termed a “gerozyme”. [14]
When skeletal muscles lose synapses, points of contact with the nerves, they atrophy and weaken, which compromises mobility and affects quality of life. Denervation can be sudden due to a traumatic injury that compresses or severs the nerves or can occur progressively over time with disease or age. A total of 3 to 5% of the population in the United States suffers from such disorders, and the available treatment options are limited. [21] [22] Blau’s laboratory showed that inhibiting the gerozyme restores neuromuscular connections after either an acute or chronic loss of synapses due injury or aging. [14]
Further experiments showed that blocking the activity of the gerozyme has a synergistic beneficial effect on muscle: enhancing the number and function of cellular energy factories called mitochondria, remodeling the arrangement of protein filaments called myofibrils that make up muscle fibers, and repressing harmful aging-associated pathways. [13] Coupled with its effect on muscle stem cells and motor axons, 15-PGDH represents a potent target for treatments designed to enhance muscle strength in those who are frail due to muscle disuse, genetic disease, or age. Blau is actively involved in efforts to translate these findings to the clinic.
Blau is an ardent inventor who holds 16 issued US patents and numerous international patents which focus on assays of protein interactions, methods for telomere extension and tissue regeneration. [23] She earned an Outstanding Inventor Award from the Stanford University Office of Technology Licensing and is recognized as one of Stanford’s top innovators. She was elected to the National Academy of Inventors in 2017. [24] Blau consults for biotechnology and pharmaceutical companies and is the founder of two companies focused on regenerative medicine to increase healthspan.
Blau is known for her support of women in science and her success in mentoring numerous young scientists who comprise the next generation of academic leaders in muscle biology, stem cell biology and regenerative medicine. She has trained more than 95 students and postdoctoral scholars and she mentors young scientists at all levels.
Blau has served on many prominent scientific advisory boards and councils, including the Harvard Board of Overseers, the National Academy of Sciences, the National Academy of Medicine, NIH National Institute on Aging, the American Academy of Arts and Sciences, the American Society for Cell Biology, American Society for Gene Therapy, Ellison Medical Foundation, and the International Society for Stem Cell Research. She has served as the president of the American Society for Developmental Biology and president of the International Society of Differentiation. She has organized numerous national and international conferences and is an elected member of the Pontifical Academy of Sciences that advises Pope Francis at the Vatican.
Blau is an active proponent of the ethical use of stem cells, fetal tissues and animals in research and she has contributed to multiple articles in the New England Journal of Medicine discussing animal research policies [25] and the use of human fetal tissue in medicine. [26] Recently, she helped implement the International Society for Stem Cell Research’s 2023 “Guidelines for Stem Cell Research and Clinical Translation”. [27]
Honors – elected member
Honorary Doctorates
Selected Awards
Planarians (triclads) are free-living flatworms of the class Turbellaria, order Tricladida, which includes hundreds of species, found in freshwater, marine, and terrestrial habitats. Planarians are characterized by a three-branched intestine, including a single anterior and two posterior branches. Their body is populated by adult stem cells called neoblasts, which planarians use for regenerating missing body parts. Many species are able to regenerate any missing organ, which has made planarians a popular model in research of regeneration and stem cell biology. The genome sequences of several species are available, as are tools for molecular biology analysis.
Cell proliferation is the process by which a cell grows and divides to produce two daughter cells. Cell proliferation leads to an exponential increase in cell number and is therefore a rapid mechanism of tissue growth. Cell proliferation requires both cell growth and cell division to occur at the same time, such that the average size of cells remains constant in the population. Cell division can occur without cell growth, producing many progressively smaller cells, while cell growth can occur without cell division to produce a single larger cell. Thus, cell proliferation is not synonymous with either cell growth or cell division, despite these terms sometimes being used interchangeably.
Regeneration in biology is the process of renewal, restoration, and tissue growth that makes genomes, cells, organisms, and ecosystems resilient to natural fluctuations or events that cause disturbance or damage. Every species is capable of regeneration, from bacteria to humans. Regeneration can either be complete where the new tissue is the same as the lost tissue, or incomplete after which the necrotic tissue becomes fibrotic.
Embryonic stem cells (ESCs) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage pre-implantation embryo. Human embryos reach the blastocyst stage 4–5 days post fertilization, at which time they consist of 50–150 cells. Isolating the inner cell mass (embryoblast) using immunosurgery results in destruction of the blastocyst, a process which raises ethical issues, including whether or not embryos at the pre-implantation stage have the same moral considerations as embryos in the post-implantation stage of development.
In cellular biology, the Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors. The name Wnt, pronounced "wint", is a portmanteau created from the names Wingless and Int-1. Wnt signaling pathways use either nearby cell-cell communication (paracrine) or same-cell communication (autocrine). They are highly evolutionarily conserved in animals, which means they are similar across animal species from fruit flies to humans.
Regenerative medicine deals with the "process of replacing, engineering or regenerating human or animal cells, tissues or organs to restore or establish normal function". This field holds the promise of engineering damaged tissues and organs by stimulating the body's own repair mechanisms to functionally heal previously irreparable tissues or organs.
Elaine V. Fuchs is an American cell biologist known for her work on the biology and molecular mechanisms of mammalian skin and skin diseases, who helped lead the modernization of dermatology. Fuchs pioneered reverse genetics approaches, which assess protein function first and then assess its role in development and disease. In particular, Fuchs researches skin stem cells and their production of hair and skin. She is an investigator at the Howard Hughes Medical Institute and the Rebecca C. Lancefield Professor of Mammalian Cell Biology and Development at The Rockefeller University.
Douglas A. Melton is an American medical researcher who is the Xander University Professor at Harvard University, and was an investigator at the Howard Hughes Medical Institute until 2022. Melton serves as the co-director of the Harvard Stem Cell Institute and was the first co-chairman of the Harvard University Department of Stem Cell and Regenerative Biology. Melton is the founder of several biotech companies including Gilead Sciences, Ontogeny, iPierian, and Semma Therapeutics. Melton holds membership in the National Academy of the Sciences, the American Academy of Arts and Sciences, and is a founding member of the International Society for Stem Cell Research.
Sean J. Morrison is a Canadian-American stem cell biologist and cancer researcher. Morrison is the director of Children's Medical Center Research Institute at UT Southwestern (CRI), a nonprofit research institute established in 2011 as a joint venture between Children’s Health System of Texas and UT Southwestern Medical Center. With Morrison as founding director, CRI was established to perform transformative biomedical research at the interface of stem cell biology, cancer and metabolism to better understand the biological basis of disease. He is a Howard Hughes Medical Institute Investigator, has served as president of the International Society for Stem Cell Research, and is a member of the U.S. National Academy of Medicine, U.S. National Academy of Sciences and European Molecular Biology Organization.
Cell potency is a cell's ability to differentiate into other cell types. The more cell types a cell can differentiate into, the greater its potency. Potency is also described as the gene activation potential within a cell, which like a continuum, begins with totipotency to designate a cell with the most differentiation potential, pluripotency, multipotency, oligopotency, and finally unipotency.
Mesenchymal stem cells (MSCs), also known as mesenchymal stromal cells or medicinal signaling cells, are multipotent stromal cells that can differentiate into a variety of cell types, including osteoblasts, chondrocytes, myocytes and adipocytes.
Myogenic factor 5 is a protein that in humans is encoded by the MYF5 gene. It is a protein with a key role in regulating muscle differentiation or myogenesis, specifically the development of skeletal muscle. Myf5 belongs to a family of proteins known as myogenic regulatory factors (MRFs). These basic helix loop helix transcription factors act sequentially in myogenic differentiation. MRF family members include Myf5, MyoD (Myf3), myogenin, and MRF4 (Myf6). This transcription factor is the earliest of all MRFs to be expressed in the embryo, where it is only markedly expressed for a few days. It functions during that time to commit myogenic precursor cells to become skeletal muscle. In fact, its expression in proliferating myoblasts has led to its classification as a determination factor. Furthermore, Myf5 is a master regulator of muscle development, possessing the ability to induce a muscle phenotype upon its forced expression in fibroblastic cells.
Margaret Buckingham, is a British developmental biologist working in the fields of myogenesis and cardiogenesis. She is an honorary professor at the Pasteur Institute in Paris and emeritus director in the Centre national de la recherche scientifique (CNRS). She is a member of the European Molecular Biology Organization, the Academia Europaea and the French Academy of Sciences.
Amy J. Wagers is the Forst Family Professor of Stem Cell and Regenerative Biology at Harvard University and Harvard Medical School, an investigator in islet cell and regenerative biology at the Joslin Diabetes Center, and principal faculty of the Harvard Stem Cell Institute. She is co-chair of the Department of Stem Cells and Regenerative Biology at Harvard Medical School.
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Valerie Horsley is an American cell and developmental biologist. She currently works as an associate professor at Yale University, where she has extensively researched the growth, restoration, and maintenance of skin cells. She is a currently a member of the Yale Cancer Center and Yale Stem Cell Center. She received a Presidential Early Career Award for Scientists and Engineers in 2012 and in 2013 she was the recipient of the Rosalind Franklin Young Investigator Award.
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