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Research Laboratories at Penn Vet


Penn Vet faculty are engaged in ongoing groundbreaking research. Here are examples of faculty laboratories and the projects being investigated, both at our Philadelphia campus and at New Bolton Center.

Brinster Laboratory of Reproductive Physiology

 Our research has involved studies on mammalian germ cells and early embryos. Initially, Ralph Brinster on transgenesiswe developed a culture system and manipulation techniques for mouse eggs that are the foundation for subsequent mammalian egg and embryo experiments in the field, including nuclear transfer and in vitro fertilization of human eggs.

We then used these methods to show that mouse blastocysts can be colonized by foreign stem cells and result in chimeric adults, which led to the development of embryonic stem cells. Subsequently, we used these culture and manipulation techniques to develop transgenic mice. In recent years, our research has focused on male germline stem cells, and these studies demonstrated that spermatogonial stem cells (SSCs) from a fertile male mouse can be transplanted to the testes of an infertile male where they will colonize the seminiferous tubules and generate donor cell-derived spermatozoa, thereby restoring fertility.

In addition, SSCs of mice and other rodents can be cultured in vitro and their number increased, and the SSCs can be frozen and preserved for long periods. The ability to culture, transplant and cryopreserve SSCs makes the germline of individual males immortal. The transplantation and freezing methods are readily transferrable to the SSCs of all mammalian species.

Ralph Brinster in ScienceHowever, a culture system for SSCs of nonrodent species has proven to be difficult to develop, and published reports of success have not been independently confirmed and are not universally accepted. Therefore, in recent studies we have attempted to develop a reliable system to culture human SSCs, which is essential to preserve and expand for later use the SSCs of prepubertal boys who will receive germ cell destroying treatment for cancer.

As part of these studies, we are establishing the genes and regulating mechanism used by mouse and human SSCs to survive and replicate, which will contribute to the understanding necessary for human SSC culture and expansion. In the long term, a culture system will also allow the development of techniques to support SSC differentiation in vitro with production of spermatozoa capable of fertilizing eggs.

In addition, the SSC assay system provides a powerful technique in which to test the conversion of somatic cells to functional SSCs. Over the past 10 years, we and others have identified transcription factors and micro RNAs that play key roles in SSC self-renewal. In current research, we plan to use this information to reprogram somatic cells into germ cells, specifically SSCs. The transplantation assay provides an unequivocal conformation of this reprogramming for a single cell.

Moreover, it allows for the identification of gene activation during the differentiation process in vivo and production of progeny from sperm produced from reprogrammed cells. In the future, the approach could be used to address fertility problems in humans and possibly the correction of genetic defects.

This research is supported by grants from National Institutes of Child Health and Human Development and the Robert J. Kleberg, Jr. and Helen C. Kleberg Foundation.

Contact Information

Ralph L. Brinster, VMD, PhD (Principal Investigator) Ralph Brinster, VMD/PhD, Penn Vet
Richard King Mellon Professor of Reproductive Physiology
Department of Biomedical Sciences
School of Veterinary Medicine, 100E
University of Pennsylvania
3850 Baltimore Avenue
Philadelphia, PA 19104-6009
Phone: 215-898-8805
Fax: 215-898-0667
Email: brinster@vet.upenn.edu

Mary AvarbockMary Avarbock, Brinster Laboratory

  • Research Specialist & Laboratory Manager


Male germline stem cell preservation. Before treatment for cancer by chemotherapy or irradiation, a boy could undergo a testicular biopsy to recover stem cells. The stem cells could be cryopreserved or, after development of the necessary techniques, could be cultured. After treatment, the stem cells would be transplanted to the patient's testes for the production of spermatozoa. The critical roadblock to widespread clinical use of this approach is the absence of culture techniques. 

Brinster: Male Germline Stem Cells


Clarence FreemanClarence Freeman, Brinster Lab
Animal Research Technician

Rosie Naroznowski, Brinster Lab 
Rose Naroznowski
Animal Research Technician

 

Testis spermatogonial stem cell transplantation method. A single-cell suspension is produced from a fertile donor testis (A). The cells can be cultured (B) or microinjected into the lumen of seminiferous tubules of an infertile recipient mouse (C). Only a spermatogonial stem cell can generate a colony of spermatogenesis in the recipient testis. When testis cells carry a reporter transgene that allows the cells to be stained blue, colonies of donor cell–derived spermatogenesis are identified easily in recipient testes as blue stretches of tubule (D). Mating the recipient male to a wild-type female (E) produces progeny (F), which carry donor genes. Genetic modification can be introduced while the stem cells are in culture.

Brinster Lab: Germline Stem Cells 

Carolyn Pope Carolyn Pope
Office Manager

Long-term science/research colleagues and support personnel indicating their years in our laboratory: Mary Avarbock (56 years); Clarence Freeman (33 years); Rose Naroznowski (39 years); Carolyn Pope (40 years), a total of 168 years. Without their support and interaction our research would never have been possible.

Wu, X., Goodyear, S. M., Abramowitz, L. A., Bartolomei, M. S., Tobias, J. W., Avarbock, M. R., and Brinster, R. L. Fertile offspring derived from mouse spermatogonial stem cells cryopreserved for more than 14 years. Human Reproduction. 2012 May; 27(5): 1249-1259. DOI:10.1093/humrep/des077; PMCID: PMC3329194. 

Oatley, J. M. and Brinster, R. L., The germline stem cell niche unit in mammalian testes. Rev. 2012 Apr; 92(2): 577-595. 2012. DOI:10.1152/physrev.00025.2011; PMCID: PMC3970841. 

Ginsberg, J. P., Li, Y., Carlson, C. A., Gracia, C., Hobbie, W. L., Miller, V. A., Mulhall, J., Shnorhavorian, M., Kolon, T. F., and Brinster, R. L. Testicular tissue cryopreservation in prepubertal male children: an analysis of parental decision-making. Pediatric Blood and Cancer. Sep. 2014; 61(9): 1673-8. DOI:10.1002/pbc.25078; PMCID: PMC4676076.

Pietzak, E. J., Tasian, G. E., Tasian, S. K., Brinster, R. L., Carlson, C., Ginsberg, J. P., and Kolon, T. F. Histological findings of testicular biopsy specimens obtained for an experimental fertility preservation technique. The Journal of Urology. 2015 Nov; 194(5): 1420-4. DOI: 10.1016/j.juro.2015.04.117; PMCID: PMC4615387.

Niu, Z., Goodyear, S. M., Avarbock, M. R., and Brinster, R. L. Chemokine (C-X-C) ligand 12 facilities trafficking of donor spermatogonial stem cells. Stem Cells International. Vol. 2016: 1-8, Article ID: 5796305. DOI: 10.1155/2016/5796305.

Goodyear, S. and Brinster, R.L. Spermatogonial stem cell transplantation to the testis. In: Cold Spring Harbor Protocol. 2017; (4): 299-305. DOI: 10.1101/pdb. prot094235; PMID: 28373495.

Goodyear, S. and Brinster, R.L. Culture and expansion of primary undifferentiated spermatogonial stem cells. In: Cold Spring Harbor Protocol. 2017; (4): 293-6. DOI: 10.1101/pdb. prot094193; PMID: 28373493.

Goodyear, S. and Brinster, R.L. Isolation of the spermatogonial stem cell-containing fraction from testes. In: Cold Spring Harbor Protocol. 2017; (4): 289-292. DOI: 10.1101/pdb. prot094185; PMID: 28373492.

Kubota, H. and Brinster, R. L. Culture and transplantation of spermatogonial stem cells. In: The Biology of Mammalian Spermatogonia. Editors: Oatley, J. M. and Griswold, M. D. Springer Publishing. 2017. Chap. 11: 271-300

Kubota, H. and Brinster, R. L. Germ Cell Transplantation. In: Encyclopedia of Reproduction, Second Edition. Aug. 2018; Vol. 1, Chap. 29, Male Reproduction. Editors: Jégou, B. and Skinner, M.K., Elsevier.

Kubota, H. and Brinster, R. L. Spermatogonial transplantation and SSC competence. In: Encyclopedia of Reproduction, Second Edition. 2018; Vol.3, Chap. 18, Gametogenesis, Fertilization and Early Development. Editors: McCarrey, J. and Wei, Y. Elsevier.

Kubota, H., and Brinster, R.L. Spermatogonial stem cells. Reprod. 2018 Mar.; 99(0) 50th Anniversary Special Issue: 1-23. DOI: 10.1093/biolre/ioy077; PMID: 29617903.

Sinha, N., Whelan, E. and Brinster, R.L. Isolation, cryopreservation, and transplantation of spermatogonial stem cells. In: Chimera Reseach: Methods and Protocols. Editors: Hyun, I. and De Los Angeles, A. Springer Science Business Media, LLC. 2019; Vol. 5, Chap. 14: 205-220. 

Ginsberg, J. and Brinster, R.L. Transplantation of Cryopreserved Spermatogonia. In: Fertility Preservation: Principles & Practice, Second Edition. 18, Fertility Preservation Strategies in the Male. Editors: Donnez, J. and Kim, S., Cambridge University Press. 2021. ISBN: 9781108494595.

Yang, F., Whelan, E., Guan, X., Bingquan, D., Shu, W., Sun, J., Avarbock, M.R, Wu, X., Brinster, R.L. FGF9 promotes mouse spermatogonial stem cell proliferation mediated by p38 MAPK signaling. Cell Prolif. 2021;54: e12933. https://doi.org/10.1111/cpr.12933.

Sinha N, Whelan EC, Tobias JW, Avarbock M, Stefanovski D, Brinster RL. Roles of Stra8 and Tcerg1l in retinoic acid induced spermatogonial differentiation in mouse. Biology of Reproduction, 2021, 1-16 doi:10.1093/biolre/ioab093

Whelan EC, Yang F, Avarbock MR, Sullivan MC, Beiting DP, Brinster RL (2022) spermatogenesis after more than 20 years of cryopreservation of rat spermatogonial stem cells reveals an important impact in differentiation capacity. PLOS Biol 20(5): e3001618. https://doi.org/10.1371/journal. pbio.300.

Of the total publications, approximately 400 are in peer-reviewed journals and 84 are chapters/reviews.  Included in the publications are 30 in Nature, 18 in Cell, 13 in Science, and 35 in Proc. Natl. Acad. Sci. USA. H-Index: 120

For a full list of publications, please visit PubMed

Dr. Ralph Brinster, VMD/PhD, Penn Vet's Richard King Mellon Professor of Reproductive Physiology, is the first veterinarian and the eighth scientist from Penn to receive the National Medal of Science since its inception in 1963. Recognized as the father of transgenesis, Dr. Brinster's research on the manipulation of the mammalian germ line gave rise to this groundbreaking field.

Here are some news stories and magazine articles on Dr. Brinster and his work:

National Medal of Science

Dr. Brinster, President Barack Obama 

Convocation Speech: http://livestre.am/56Cfg Introduction begins at time 35:10.

Read the article about Dr. Brinster

Dr. Brinster, Penn Vet

  • Penn Research Points to New Way of Preserving Fertility for Boys Undergoing Cancer Treatment.

Winter 2012 Bellwether, Dr. Brinster

Here are additional resources to learn more about Dr. Brinster and the Brinster Laboratory of Reproductive Biology:

 Ralph L. Brinster

Personal

Military Service: 1954-1956 Lieutenant, USA.
Korean War Veteran

Office

Office address: School of Veterinary Medicine
University of Pennsylvania
Philadelphia, Pennsylvania 19104
Telephone: (215) 898-8805
Email: brinster@vet.upenn.edu

Education

1949-53 BS, School of Agriculture, Rutgers University

1956-60 VMD, School of Veterinary Medicine, University of Pennsylvania

1960-64 PhD (Physiology), Graduate School of Arts & Sciences, University of Pennsylvania

Additional Training

1960 Postdoctoral Fellow, Jackson Laboratory, Bar Harbor, Maine, Summer.

1962 Postdoctoral Fellow, Marine Biological Laboratory, Woods Hole, Massachusetts, Summer.

Appointments

1960-64 Teaching Fellow, Department of Physiology, School of Medicine, University of Pennsylvania.

1964-65 Instructor, Department of Physiology, School of Medicine, University of Pennsylvania.

1965-66 Assistant Professor of Physiology, Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, USA.

1966-70 Associate Professor of Physiology, Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania.

1968-83 Founding Program Director and Director, Reproductive Physiology Training Program, School of Veterinary Medicine, University of Pennsylvania.

1969-84 Founding Program Director and Director, Veterinary Medical Scientist Training Program, School of Veterinary Medicine, University of Pennsylvania.

1970-75 Professor of Physiology, School of Veterinary Medicine, University of Pennsylvania.

1975- Richard King Mellon Professor of Reproductive Physiology, School of Veterinary Medicine and Graduate School, University of Pennsylvania.

1997-07 Scientific Director, Center for Animal Transgenesis and Germ Cell Research, School of Veterinary Medicine, University of Pennsylvania

2007-08 Founding Co-Director, Institute for Regenerative Medicine, University of Pennsylvania.

Fellowships

1960-61 American Veterinary Medical Association Fellow, Graduate School Arts & Sciences, University of Pennsylvania.

1961-64 Pennsylvania Plan Scholar, Graduate School of Arts & Sciences, University of Pennsylvania.

Honors

New York Academy of Sciences Award in Biological and Medical Sciences, 1983.

Harvey Society Lecturer, 1984.

Member of the National Academy of Medicine, 1986.

Fellow of the American Academy of Arts and Science, 1986.

Member of the National Academy of Sciences, 1987.

Honored (with L. Stevens) by an International Symposium at W. Alton Jones Cell Science Center (for pioneering work on development of the teratocarcinoma model and transgenic animals), 1987.

Fellow of the American Association for the Advancement of Science, 1989.

Distinguished Service Award of U. S. Department of Agriculture, 1989.

Invited Speaker at the Nobel Symposium on “Genetic Control of Embryonic Development”, 1991.

Pioneer Award from the International Embryo Transfer Society, 1992.

Juan March Foundation Lecture, Madrid, Spain, 1992.

Fellow of the American Academy of Microbiology, 1992.

Doctor Honoris Causa in Medicine, University of the Basque Country, Spain, 1994.

Charles-Léopold Mayer Prize (with R. Palmiter), The highest prize of the French Academy of Sciences (for development of transgenic animals), 1994.

Alumni Award of Merit, School of Veterinary Medicine, University of Pennsylvania, 1995.

First March of Dimes Prize in Developmental Biology (with B. Mintz) (for critical work in development of transgenic mice), 1996.

Carl Hartman Award, Society for the Study of Reproduction, 1997.

Bower Award and Prize for Achievement in Science, the Franklin Institute (for development of methods to transfer foreign genes into animals), 1997.

John Scott Award for Scientific Achievement, the City Trusts of Philadelphia, 1997.

Pioneer in Reproduction Research Award, The National Institute of Child Health & Human Development, National Institutes of Health, 1998.

Honored by a Special Festschrift Issue of the International Journal of Developmental Biology “Stem Cells and Transgenesis”, 1998.

George Hammel Cook Distinguished Alumni Award, Rutgers University, 1999.

Charlton Lecture, Tufts University School of Medicine, 2000.

Honorary Doctor of Science Degree, Rutgers, the State University of New Jersey, 2000.

Ernst W. Bertner Award, University of Texas M. D. Anderson Cancer Center (for research discoveries enabling development of transgenic animals), 2001.

Highly Cited Researcher (1980-2000), Designated by the Institute for Scientific Information, 2002. About 1 in 1000 authors are in this category.

Selected for the Hall of Honor, National Institute of Child Health and Human Development, 2003, (1 of 15).

Wolf Prize in Medicine, Israel (with M. Capecchi and O. Smithies) (for introducing and modifying genes in mice), 2003.

Canada Gairdner International Award, Canada (for pioneering discoveries in germ line modification in mammals), 2006.

National Medal of Science, USA (for fundamental contributions to the development of transgenic mice), 2010.

International Society for Transgenic Technology Prize for outstanding contributions to the field of transgenic animals and stem cells, 2011.

Lifetime Achievement Award. From the Alumni of the University of Pennsylvania School of Veterinary Medicine, 2012.

Career Excellence in Theriogenology Award. From the Theriogenology Foundation on behalf of the American College of Theriogenologists and the Society for Theriogenology, 2012.

Honorary Doctor of Laws, University of Calgary, Canada, 2015

Fellow of the American Physiological Society, 2015.

Ralph L. Brinster President’s Distinguished Professorship, University of Pennsylvania, 2017.

Frontiers of Germ Cell Research. Brinster Spermatogonial Stem Cell Transplantation 25th Anniversary Symposium, University of Pennsylvania, 2019.

Ralph L. Brinster Annual Symposium. Institute for Regenerative Medicine, School of Medicine, University of Pennsylvania, 2022.