Dr. Simon John
Dr. John is an Investigator of the Howard Hughes Medical Institute and Professor at The Jackson Laboratory. He is also a Research Assistant Professor in Ophthalmology at Tufts University School of Medicine and on the Graduate Faculty at the University of Maine. He received his B.Sc. degree - with joint honors in zoology and genetics - from University College Cardiff, South Wales. He earned his Ph.D. in Biology (studying human genetics) from McGill University, where he worked with Rima Rozen and Charles Scriver on the genetics of phenylketonuria. His postdoctoral training was with Nobel Laureate Oliver Smithies, at the University of North Carolina at Chapel Hill, studying genes contributing to essential hypertension. Read Dr. John's Bio
B.Sc., 1985, Joint Honors Zoology and Genetics, University College Cardiff, South Wales, UK Thesis: Chromosome Studies of the Brown Planthopper Nilaparvata lugens (Stål) Supervisor: Dr. Jerome Den Hollander
Ph.D., 1992, Biology, McGill University, Biology Department, Montreal, Canada Thesis: Haplotypes and Mutations at the Phenylalanine Hydroxylase Locus in French Canadians Supervisors: Dr. Charles R. Scriver and Dr. Rima Rozen
NEI Course:August 1994, Fundamental Issues in Vision Research, Woods Hole, MA, USA
1991 - 1995 Postdoctoral Fellow in the laboratory of Dr. Oliver Smithies, Excellence Professor of Pathology, University of North Carolina, Chapel Hill, NC, USA
1995 - Present Associate Staff, Staff and then Senior Staff Scientist/Professor (since 2006, institutional title change to professor system in 2008), The Jackson Laboratory, Bar Harbor, ME
1997 - Present Research Assistant Professor, Ophthalmology, Tufts University School of Medicine, Boston, MA
1998 - Present Assistant Investigator, Associate Investigator and then Investigator (since 2005), Howard Hughes Medical Institute
2000 - Present Graduate Faculty, The University of Maine
2003 - Present Cooperating Professor, Functional Genomics, University of Maine, Orono
2010 - Present Clinical Collaborator, Center for Implantable Devices, Purdue Unversity, West Lafayette, IN
2011 - Present Graduate Professor, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA
1985 B.Sc. Magna Cum Laude
1989 Canadian Society of Clinical Investigation Student Award
1995 Becton Dickinson Young Investigator Fellowship
1997 Ruth Salta Junior Investigator Achievement Award
1998 Ruth Salta Junior Investigator Achievement Award
2004 Cogan Award from the Association for Research in Vision & Ophthalmology
2004 Lewis Rudin Glaucoma Prize
2006 Global Glaucoma Award from the Association of International Glaucoma Societies
2008 Alcon Research Institute Award
2013 Bressler Vision Science Award
2014 Lewis Rudin Glaucoma Prize
2015 Lewis Rudin Glaucoma Prize
Simon John attributes his early interest in science to a library book about rainbows, an uncle who taught him to use a microscope, and the snakes he caught near his Welsh hometown. His passion for genetics was sparked by his father, who bred finches as a hobby. John watched with amazement as his father mated the drabbest birds to produce offspring with stunning cinnamon plumage. “That got me interested in natural variation from a very early age,” he says.
John now studies the genetics of glaucoma, a potentially blinding eye disease that affects up to 70 million people worldwide. It results from damage to the optic nerve and is often preceded by high intraocular pressure. Partly because of his own poor eyesight, John empathizes with people who have more serious problems. “I want to understand the mechanism of glaucoma, with the goal of suggesting new ways to improve vision care,” he explains.
He became interested in this complex disease while studying the causes of high blood pressure, because he wondered if certain peptides might also control pressure inside the eye. Scouring the scientific literature, he was shocked to discover how little was known about glaucoma at the molecular level.
When he moved to the Jackson Laboratory in Maine in 1995, John decided to study glaucoma in an animal model. “I thought it would be easy to take the genes we had implicated in high blood pressure and work with them in the mouse eye,” he says.
But many scientists who studied glaucoma at that time had a low opinion of the mouse. “Some people told me I was wasting my time using mice for glaucoma research, because mice were anatomically inappropriate,” John says.
Through painstaking anatomical studies, John showed that the pertinent structures in the eyes of mice and men have a lot in common. Over their early years at the Jackson Laboratory, he and his group developed the first mouse models of glaucoma, developed the necessary tools for studying them, and adapted human eye exams to mice. “Now all of the powerful tools of classical and modern mouse genetics can be used to study glaucoma,” he says. “I’m very proud of the way that has taken off.”
Using one of these mouse models, John’s group discovered that errors in a gene that codes for a type of collagen cause a glaucoma-like condition. Realizing that this collagen also strengthens blood vessels, they showed that the gene predisposes mice and humans to bleeding in the brain. “This work suggests possible behavioral and medical interventions that could massively reduce the risk of hemorrhagic complications and sudden death in families with this gene,” John says. “For example, individuals in those families could avoid playing contact sports or exercising too vigorously.”
Other mouse models have generated some surprising suggestions for preventing glaucoma. John studied a mouse with defects in a gene called Cyp1b1, which human geneticists had associated with a devastating glaucoma of infants and toddlers. By crossing those mice and strains with other genetic constitutions, John discovered a gene that modulates the effects of Cyp1b1 defects on the eye. That gene codes for an enzyme that makes L-DOPA, a naturally occurring amino acid used to treat Parkinson’s disease. When John’s group spiked the drinking water of female mice with L-DOPA before and during pregnancy, the effects of the Cyp1b1 defects were largely prevented. “That’s very exciting, because there are many ways to adjust L-DOPA levels,” he says. If L-DOPA has the same effect in humans and passes the appropriate safety trials, it could be given to pregnant women who have a defective Cyp1b1 gene and whose children are at risk for glaucoma. Or such women might get enough L-DOPA simply by eating beans.
Another insight into glaucoma prevention was totally unexpected. John was studying mice that are prone to a type of glaucoma in which the iris falls apart and the eye’s drainage channels become damaged by pigment and debris. By the time the animals are middle aged, their optic nerve is usually ruined because of the high pressure inside the eye.
To explore mechanisms contributing to this condition, John’s group gave the mice one high dose of radiation before transplanting them with bone marrow. As the animals aged, most of them had healthy optic nerves, even though they still had iris disease and high intraocular pressure. “We could hardly believe it. That was the biggest surprise of my career,” says John, who then contacted scientists who are following the lives of more than 10,000 survivors of the Hiroshima and Nagasaki atomic bombs. It turned out that the survivors who received the highest dose of radiation from the atomic bombs were the least likely to have glaucoma.
In collaboration with physicists and engineers, John is devising ways to target specific amounts of radiation to parts of the tiny mouse eye so he can determine the molecular mechanism of protection. If this project pans out in mice and humans, it might one day be possible for ophthalmologists to give patients a dose of radiation that would be as safe as a dental x-ray and that would protect against glaucoma for life. “That’s a pipe dream right now,” John says. “But it will be fantastic if it works.”
Dr. John has served on various advisory panels to the National institutes of Health and other agencies. He is a member of various professional organizations including the American Association for the Advancement of Science and the Society for Neuroscience. He has received various awards for his research. Dr. John was honored in both 1997 and 1998 with the Ruth Salta Junior Investigator Achievement Award from the National Glaucoma Research Program of the American Health Assistance Foundation. He received the Cogan Award in 2004 from the Association for Research and Visual Science, to recognize his important contributions to ophthalmology and visual science. Also in 2004, he received the Lewis Rudin Glaucoma Prize from the New York Academy of Medicine for outstanding work in glaucoma. In 2006, he received the Global Glaucoma Award from the Association of International Glaucoma Societies for daring, breakthrough, creative, original body of work and for most important glaucoma paper in 2005.