by Janice Fisher
The road to discovery of the Myo/Nog lineage began almost 30 years ago with the identification of 10 skeletal muscle stem cells that were hidden among a hundred thousand other cells鈥攖he veritable needle in the haystack.
鈥淲e were asking a relatively simple question, using the chick embryo as the model,鈥�
says Mindy George-Weinstein, PhD, chief research and science officer, 黑料传送门.
鈥淭he question was: When does skeletal muscle begin to develop in the embryo? The dogma
at the time was that embryonic cells were naive until they received signals from the
developing spinal cord to become programmed to form muscle.鈥� But two reports in the
literature caught the eye of Dr. George-Weinstein. Researchers Howard Holtzer, PhD,
and Michael Solursh, PhD, had found that muscle could develop from early embryos before
the formation of the spinal cord if cells were grown in the presence of a rich, undefined
mixture of molecules. 鈥淲e decided to take a closer look.鈥�
The first step involved culturing embryonic cells in the absence of molecules seen within the embryo itself. Lo and behold, muscle appeared. Next, the George-Weinstein lab found 10 to 20 cells that contained MyoD, a molecule that drives skeletal muscle development. Visualizing MyoD was possible using three-dimensional DNA nanoparticles (3DNA) developed by PolyProbe, a company whose laboratory was housed at 黑料传送门. The group then discovered that the cells with MyoD released a molecule called Noggin, an inhibitor of bone morphogenetic proteins (BMPs) that are present in the embryo and adults. (The scientists who had discovered Noggin applied this name because a mutated form produces malformations of the head.)
The cells found in the George-Weinstein lab were named Myo/Nog for their dual roles as precursors to muscle and factories for Noggin production. Myo/Nog cells were also identified with an antibody called G8. 鈥淭he beauty of this antibody,鈥� says Dr. George-Weinstein, 鈥渋s that it binds to the cell surface. We could apply the antibody to living embryos to track Myo/Nog cells, isolate the cells to study their properties in culture, and kill them.鈥�
For almost 20 years, the George-Weinstein lab studied the roles of Myo/Nog cells during embryonic development. 鈥淎s organs are forming,鈥� explains Dr. George-Weinstein, 鈥淢yo/Nog cells become integrated into many different tissues, some that have muscle and some that don鈥檛.鈥� The tiny population of Myo/Nog cells present in the early embryo is critical for muscle formation and development of multiple organs, including the eyes, heart and brain.
鈥淥ne unique feature of Myo/Nog cells,鈥� says Dr. George-Weinstein, 鈥渋s their stubbornness to remain as both a muscle precursor cell and a cell that produces Noggin regardless of their environment.鈥� As it turns out, Myo/Nog cells are also found in normal and diseased tissue of adult mice, rats, rabbits and humans. They not only produce Noggin; they migrate very quickly to sites of injury. That鈥檚 where the story gets even more interesting.
Based on the lab鈥檚 discovery that killing Myo/Nog cells disrupts normal eye development in the chick embryo, they began to study their roles in the more mature lens and retina. In collaboration with a group of researchers at Thomas Jefferson University, they found that Myo/Nog cells developed into a type of muscle cell called a myofibroblast, in response to wounding of the chick lens. The George-Weinstein lab then made the leap to adult human eyes, where Myo/Nog cells were found in low numbers.
Again, the group found themselves overturning a dogma in the field. Myofibroblasts in the lens were presumed to develop from epithelial cells that along with their mature derivatives, the lens fiber cells, were thought to be the only cells in the lens. Using human lens tissue removed during cataract surgery, they discovered that Myo/Nog cells are the source of contractile myofibroblasts that resemble skeletal muscle cells. 鈥淭he problem with myofibroblasts is that their contractions produce wrinkles in the capsule that surrounds the lens. These wrinkles can affect the pathway of light as it passes through the lens on its way to the retina,鈥� says Dr. George-Weinstein. This phenomenon occurs in a disease called posterior capsule opacification (PCO), or secondary cataract. Between 15 and 30 percent of adults, and almost all children, get PCO after cataract surgery. This vision-impairing disease can be treated with laser, but side effects, some serious, can occur, and laser surgery isn鈥檛 available worldwide.
Since it can鈥檛 be predicted which adults will get PCO, ideally a drug that kills Myo/Nog cells could be given to everyone having cataract surgery. The George-Weinstein lab developed such a drug in collaboration with Robert Getts, PhD, vice-president of research and development and chief scientific officer at Genisphere LLC, a company that evolved from PolyProbe. The G8 antibody used for targeting the drug to Myo/Nog cells was attached to 3DNA nanoparticles containing a toxic molecule called doxorubicin that鈥檚 commonly used for cancer chemotherapy. In a recently published paper, the team reported that this novel drug specifically kills Myo/Nog cells and prevents the emergence of myofibroblasts in cultures of human lens tissue. In collaboration with veterinarians at the University of Utah, the drug is currently being tested for its ability to reduce PCO in rabbits undergoing cataract surgery.
Myo/Nog cells are also present in the retina. Arturo Bravo-Nuevo, PhD, at Jefferson University, and Alice Brandli, PhD, and Jonathan Stone, PhD, both at the University of Sydney, have explored the roles of Myo/Nog cells in two models of retinal disease鈥攔etinopathy of prematurity, which afflicted Stevie Wonder and Ray Charles, and light damage. Their publications describe the effects of either eliminating or adding Myo/Nog cells to the diseased retina. Myo/Nog cells were shown to be important for preserving the viability and function of photoreceptor cells that respond to light. The next step is to determine how Myo/Nog cells protect the retina. 鈥淚f their protective effects are mediated by releasing a molecule, then hypothetically the molecule itself could be injected into the eye instead of the cells,鈥� says Dr. George-Weinstein. 鈥淭his approach would circumvent the formation of muscle from injected Myo/Nog cells whose contractions could have devastating effects on vision.鈥�
鈥淭he take-home message from our work is that Myo/Nog cells might be good guys or bad guys鈥攐r even both, in the same organ. That鈥檚 what makes these cells so interesting to study,鈥� says Dr. George-Weinstein. In the embryo and the retina, Myo/Nog cells orchestrate normal development and protect cells from damage. While Myo/Nog cells are critical for lens development, they contribute to PCO with their contractions. 鈥淚n some wounds, such as diabetic ulcers, the addition of Myo/Nog cells may help with healing,鈥� suggests Dr. George-Weinstein. On the other hand, sometimes injury leads to scar tissue formation, for example after a myocardial infarction. 鈥淲e know that Myo/Nog cells are present in the heart, kidney and lungs. Do they mediate normal wound healing, deposit scar tissue, or both鈥攁nd if the answer is both, what flips the switch?鈥�
Myo/Nog cells are also present in tumors. The group has proposed that Myo/Nog cells
may indirectly affect the behavior of cancer cells. In animal models, an increase
in Noggin promotes skin cancer, and in human skin tumors, the number of Myo/Nog cells
correlates with the extent of invasion. While Myo/Nog cells may act indirectly in
some tumors, a second hypothesis, and one that Dr. George-Weinstein has been eager
to test for years, is that the Myo/Nog cell itself might be the stem cell for cancers
with muscle-like properties. In both scenarios, eliminating Myo/Nog cells may be therapeutic.
Mindy George-Weinstein, PhD, chief research and science officer, has spent three decades discovering, targeting and closely observing Myo/Nog cells. Her pioneering work is presently the focus of a multi-institutional consortium consisting of four separate yet interrelated research projects.
These questions and hypotheses will be addressed in a multi-institutional consortium of Myo/Nog cell researchers. Dr. George-Weinstein and Ms. Gerhart will continue their studies of targeting Myo/Nog cells in the lens to prevent PCO. Mark Byrne, PhD, of Rowan University is working with the scientists at Genisphere and Dr. George-Weinstein and Ms. Gerhart to develop a more effective method of drug delivery. Dr. Bravo-Nuevo and Nancy Philp, PhD, of Thomas Jefferson University will be studying the neuroprotective properties of Myo/Nog cells. The role of Myo/Nog cells in fibrosis and sarcomas will be investigated by Kathryn Behling, MD, PhD, of Cooper Medical School of Rowan University.
Dr. George-Weinstein describes the multi-institutional consortium as 鈥渁n integrated and collaborative fact-finding mission that promotes the flow of ideas and data between investigators focused on a single cell type in multiple diseases.鈥� Dr. George-Weinstein notes that the entire body of work was made possible by her 30-year collaboration with Ms. Gerhart.
鈥淛ackie invented the techniques required for the experiments, generated and interpreted data, and contributed to the overall vision of the projects that were supported by 黑料传送门, the NIH and multiple foundations over the years. Jackie鈥檚 work was described by reviewers of our manuscripts as a technical tour-de-force.鈥� Many talented MS and DO students were also instrumental in uncovering the mysteries of Myo/Nog cells.
鈥淚t鈥檚 incredible,鈥� reflects Dr. George-Weinstein, 鈥渢hat what appeared to be a simple question which we answered in the chick embryo has led to the development of potential therapies for human diseases. This extremely fulfilling journey, like most research, has had its struggles that were overcome with persistence and hard work. The winding path began at 黑料传送门. We are thrilled to have returned to our roots for the next stage of the journey.鈥�
When Jacquelyn Gerhart became 黑料传送门鈥檚 laboratory coordinator of the scientific support staff and bio-imaging core facility in 2015, it was a definitive homecoming. Her campus home, the bio-imaging core facility in Evans Hall, is precisely where she began her 黑料传送门 career in 1987, right out of college. It was then the electron microscopy suite; she recalls two electron microscopes, one of them room-sized. Today, a range of more sophisticated devices have joined those microscopes鈥攏ow much smaller and more powerful.
Ms. Gerhart is responsible for helping faculty and research staff from the Philadelphia and Georgia campuses with microscopy, cytology and related techniques. She also coordinates the efforts of the research support staff, participates in interviewing applicants for research positions, and orients new employees. Ms. Gerhart spends approximately 20 percent of her time conducting her own research.
In 1990, Ms. Gerhart began working with Dr. George-Weinstein when 鈥渢he chick system was up and running. We were looking for an antibody that we could use to study skeletal muscle, and that鈥檚 where it all began.鈥� The productivity and longevity of their collaboration (which continued even when they were not at 黑料传送门) is perhaps no longer so unusual among contemporary women scientists. But Ms. Gerhart remembers chatting at a professional meeting with the late Elizabeth Hay, MD, a pioneering cell and developmental biologist. As they stood in a line for the women鈥檚 bathroom, Dr. Hay commented that she hadn鈥檛 always had to wait in such lines because there were so few women in the field.
The collaborative culture of 黑料传送门 was a powerful lure for Ms. Gerhart. She knows that if she鈥檚 not able to check on the well-being of her cultures containing human lens tissue, for example, 鈥渢here鈥檚 always someone who is willing to help out, from the people we鈥檝e hired right out of college to staff that have been here for 20 or more years.鈥� Students volunteer to work at night; they tell her, 鈥淚 live right here, and I can come in and take care of this for you.鈥� Students who worked in the lab with Ms. Gerhart and Dr. George-Weinstein stay in touch, seeking updates on their research as well as opportunities to network among the web of connections formed in their nurturing environment. Ms. Gerhart has mentored biomedical studies students on the research track, as well as research-loving DO students. She also welcomed undergraduates from Cabrini College and high school students from Lower Merion High School, her alma maters.
The continuous opportunity to innovate sweetened her return to 黑料传送门. 鈥淪ome of the things we do haven鈥檛 been done before,鈥� she notes, 鈥渙r we had to modify someone else鈥檚 procedure to fit our project. Sometimes you have to sit there and think: 鈥楾his is what we need to do. But how are we going to do it?鈥欌�� In the early work with chick embryos, she recalls, 鈥渨e had to figure out a way to grow the embryos so we could watch them develop in the absence of Myo/Nog cells. Right after the egg was laid we would cut a window in the shell and cover it with plastic wrap to watch them grow.鈥� Ms. Gerhart, an artist, relied regularly on an art supply catalogue, following a recommendation by a fellow artist, the late Camille DiLullo, PhD, professor of anatomy, department of bio-medical sciences. 鈥淭ools for fine work in sculpture helped me manipulate embryos,鈥� says Ms. Gerhart. 鈥淐rocus cloth, used to sand art projects, was perfect for sharpening our knives.鈥�
Ms. Gerhart points to a desk drawer. 鈥淚 have my box of tools right here, and no one is allowed to touch them; they are mine,鈥� she says mildly. 鈥淚 made them 20 years ago, and they still work and I still pull them out if I need them.鈥� She remembers working with tissue sections 鈥渢hat are so thin you can barely see them; you have to float them on water and get the water to reflect just right to find them. To move them, you had to pull out an eyelash and glue it to a stick.鈥�
Years ago, learning how to perform a dissection under the microscope, Ms. Gerhart worried, 鈥淚 can鈥檛 even see what we鈥檙e cutting!鈥� Finally, 鈥渢he light was just right, and I saw it. So I tell students, don鈥檛 worry; eventually it鈥檚 just going to light up for you.鈥� What鈥檚 necessary, she stresses, is patience. 鈥淵ou have to be willing to sit and try things, or it鈥檚 not going to work.
鈥淛ust the other day I called Mindy to say, 鈥榊ou鈥檝e got to come over and see this!鈥� Mindy was as excited as I was. Leadership comes from the top down, so a leader who is excited will get everyone else excited. I think research at 黑料传送门 will do really well under her leadership as the chief research and science officer.鈥�
Ms. Gerhart and Dr. George-Weinstein continue to work together to test potential therapeutics that target Myo/Nog cells. Ms. Gerhart collaborates with Dr. Getts and his staff at Genisphere; Dr. Byrne, at Rowan University; and Liliana Werner, MD, PhD, at the University of Utah, to develop a drug that kills Myo/Nog cells to prevent secondary cataract formation.
Ms. Gerhart recalls 鈥渁 fantastic 黑料传送门 student鈥� who was recommended to the lab by his former undergraduate research mentor. The student was Mitchell B. Crawford, DO 鈥�15. Dr. Crawford quickly learned how to dissect the delicate tissues of the embryo, a variety of histological procedures and novel approaches to culturing human tissue. 鈥淲e relied upon Mitch鈥檚 imagination and ability to integrate information during brainstorming sessions in which we designed and interpreted experiments,鈥� says Dr. George-Weinstein. Like other lab members, he coauthored several papers with Ms. Gerhart and Dr. George-Weinstein.
Dr. Crawford describes Ms. Gerhart and Dr. George-Weinstein as great teachers. 鈥淭he lab was such a welcoming environment; Jackie and Mindy were so kind and so eager to teach and have me be a part of anything I was willing to help out with. It was just a brilliant place to learn.
鈥淭he lens project was pretty exciting,鈥� he says. 鈥淲e were doing things that we didn鈥檛 know how to do鈥攁nd no one else did, either. How do you take human tissue straight from the OR without damaging it? What kinds of solutions should be used? What鈥檚 the right temperature and humidity for the incubators? We were learning as we went along.鈥�
While Dr. Crawford misses working in the lab, he puts to use the skills he developed at the bench in multiple clinical research projects that engage him now, as a second-year psychiatry resident at the Harvard South Shore Psychiatry Training Program, Harvard Medical School/VA Boston Healthcare, Brockton, Massachusetts.
Dr. George-Weinstein鈥檚 concern with children who suffered from ocular diseases made a strong impression on Dr. Crawford. 鈥淲e talked about an eye drop that might be given on mission trips to kids in Third World countries. Some people say that psychiatry isn鈥檛 the most prestigious or financially rewarding specialty. My experience with Mindy and the lab helped orient me and remember that it鈥檚 important to do what you think is important in life.鈥�
When Jordanna Perlman Quinn, DO, MS/Biomed 鈥�02, joined the George-Weinstein lab, she began at the very beginning: by learning what a stem cell is. 鈥淚t wasn鈥檛 yet known that stem cells programmed to produce skeletal muscle are present in the very early embryo,鈥� she says. Dr. George-Weinstein and Ms. Gerhart 鈥渢ook me under their wing, and taught me how to work in a lab.鈥�
Today, Dr. Quinn鈥檚 practice of regenerative medicine in Golden, Colorado, includes stem cell injections into her patients to help them grow cartilage.
Dr. Quinn, who received her DO from Western University of Health Sciences in Pomona, California, is board certified in physical medicine and rehabilitation, and maintains a musculoskeletal/sports-based practice with a special interest in a natural medical approach. She describes herself as 鈥渉aving one foot in Western medicine and another in the holistic approach.鈥�
鈥淛ordanna had a broad view of medicine and healing, and she embraced the osteopathic philosophy,鈥� says Dr. George-Weinstein.
Dr. Quinn recalls 鈥渓iving in the lab, day in and day out, with Jackie or by myself, extracting stem cells from quail eggs and chick eggs. It was a lot of work鈥攍ate nights, and intense.鈥� She developed the protocol for isolating Myo/Nog cells, a procedure that is currently utilized for analyses of their properties in normal and diseased adult tissues. 鈥淛ordanna鈥檚 contributions were enormous. She was exceptionally smart, dedicated and an absolute pleasure to work with,鈥� recalls Dr. George-Weinstein.
Dr. Quinn won the Sigma Xi Award for outstanding research, and was the coauthor (as Jordanna Perlman) of several papers with Ms. Gerhart and Dr. George-Weinstein. But her experiences in the lab influenced her beyond the realm of science. Throughout her career, Dr. Quinn has pondered how to inspire the people who work for her.
鈥淚 see now that Mindy was a great work model,鈥� she says. 鈥淭he atmosphere in the lab was wonderful, and that makes you want to work harder. We had so much fun, but not at expense of hard work.鈥� Dr. Quinn adds, 鈥淛ackie and Mindy were both so passionate about their work. That鈥檚 infective; you can鈥檛 help but be interested.鈥�
Besides Dr. George-Weinstein and Ms. Gerhart, the following 黑料传送门-affiliated students, faculty and technicians performed experiments that led to publications, presentations and grants. Most are coauthors on one or more of 26 peer-reviewed published papers arising from the work of the George-Weinstein lab. The first of these papers was published in Developmental Biology in 1991. Their most recent manuscripts will appear in PLOS ONE and the Journal of Pharmacology and Experimental Therapeutics early in 2017.
Brian A. Bast, DO 鈥�02
Michael C. Baytion, MS/Biomed 鈥�98
Joanna N. Capparella, DO 鈥�97
Eric T. Cochran, MS/Biomed 鈥�97, DO 鈥�01
Mitchell B. Crawford, DO 鈥�15
Rocco J. Crescenzo, DO 鈥�92, clinical assistant professor, internal medicine, 黑料传送门
Jeffrey T. Dare, MS/Biomed 鈥�97, DO 鈥�02
Steven M. DeLuca, MS/Biomed 鈥�98, DO 鈥�02
Camille DiLullo, PhD, professor of anatomy, bio-medical sciences [deceased]
Kevin M. DuPrey, DO 鈥�10
Justin L. Elder, DO 鈥�07
Joseph M. Flynn, DO 鈥�96
Gerard J. Foti, DO 鈥�94
Carolyn E. Miehle Ianieri, DO 鈥�95
Stephanie K. Iem, MS/Biomed 鈥�03
Tage Nielsen Kvist, PhD, professor emeritus, bio-medical sciences, 黑料传送门
Christian S. Lopez, MS/Biomed 鈥�99
Luis Alberto Narciso, DO 鈥�08
Christine Neely, technician
Robert Niewenhuis, PhD, professor emeritus, bio-medical sciences, 黑料传送门
Michele E. Paessler, DO 鈥�97
Jessica Pfautz, technician
Jordanna Perlman Quinn, MS/Biomed 鈥�02
Rebecca A. Reed, DO 鈥�97
Beth A. Ricci, DO 鈥�95
Jared S. Schure, MS/Biomed 鈥�05
Eileen P. Simak, DO 鈥�00
Jennifer Leigh Sobel, DO 鈥�99
Larry Wayne Spector, DO 鈥�94
Adam C. Steinberg, DO 鈥�98
Benjamin Leslie Stewart II, DO 鈥�05
Robert J. Strony, DO 鈥�03
Dolores R. Tornambe, MS/Biomed 鈥�06, DO 鈥�10