Franklin Hamra, Ph.D.

Assistant Professor

Department: Pharmacology

Graduate Programs: Cell Regulation, Genetics and Development

Biography

F. Kent Hamra was born in Kennett,Missouri in 1965.  He received his B.S. in Zoology at Southern Illinois University in Carbondale in 1989, and then went on to work with Dr. Mark G. Currie studying nitric oxide synthases and soluble guanylyl cyclases at Monsanto Company in St. Louis, Missouri from 1990-1992.  He earned his Ph.D. in Pharmacology in the laboratory of Dr. Leonard R. Forte at the University of Missouri-Columbia (MIZZOU-RA!) in 1995 where he discovered the polypeptide hormone, Uroguanylin.  Uroguanylin is an endogenous ligand for the highly pathogenic heat-stable enterotoxin receptor-guanylyl cyclase. Kent went on to do his postdoctoral training in the Department of Pharmacology at UT Southwestern Medical Center in Dallas with Dr. David L. Garbers (HHMI), and co-mentor, Dr. Robert E. Hammer (HHMI – Biochemistry), where he invented culture conditions for isolating, propagating and genetically modifying sperm stem cells using the rat model (1996-2000).  Dr. Hamra was promoted to Instructor in 2000, Research Assistant Professor in 2004, and to Assistant Professor in 2010 in the Department of Pharmacology at UT Southwestern in Dallas, where he continues his research on germline stem cells, spermatozoan development and fertility regulation.

Dr. Hamra's research is based on the extraordinary biomedical potential of Sperm Stem Cells as it relates to advancing animal genetics, species conservation, human reproduction and well being (visit Hamra Lab).  Anatomically, sperm stem cells are technically termed “spermatogonial stem cells” (1), and function in testes by continuously regenerating mature spermatozoa for fertilizing eggs (2).  Sperm stem cells are also remarkable in that they can fully transform back into a pluripotent, embryonic stem cell state when cultured outside testes under specific growth conditions.  Given this special nature, understanding the biology of sperm maturation will lead to new strategies to rescue male factor infertility, discovery of gene targets for synthesizing male-directed contraceptives, novel avenues in regenerative medicine, and new genetic technologies to facilitate biological discovery and promote industry on a global scale.

1. The germline stem cell niche unit in mammalian testes. Oatley JM, Brinster RL., Physiol Rev. 2012 Apr;92(2):577-95.

2. Generation of pluripotent stem cells from neonatal mouse testis.  Kanatsu-Shinohara M, Inoue K, Lee J, Yoshimoto M, Ogonuki N, Miki H, Baba S, Kato T, Kazuki Y, Toyokuni S, Toyoshima M, Niwa O, Oshimura M, Heike T, Nakahata T, Ishino F, Ogura A, Shinohara T.,  Cell. 2004 Dec 29;119(7):1001-12.

Education

Undergraduate Southern Illinois University-Carbondale (1989), Zoology
Graduate School University of Missouri-Saint Louis (1995), Pharmacology

Research Interests

  • Advancing Genetics in the Laboratory Rat
  • Genetic Basis of Spermatogenesis
  • Mechanisms of Spermatogonial Development
  • Mutagenesis in the Rat using Sperm Stem Cells
  • Targeting Spermatozoan Development for Fertility Management

Publications

Featured Publications Legend

Featured Publications

Autoimmune epididymoorchitis is essential to the pathogenesis of male-specific spondylarthritis in HLA-B27-transgenic rats.

Taurog JD, Rival C, van Duivenvoorde LM, Satumtira N, Dorris ML, Sun M, Shelton JM, Richardson JA, Hamra FK, Hammer RE, Tung KS Arthritis Rheum. 2012 Aug 64 8 2518-28

Sleeping Beauty transposon mutagenesis in rat spermatogonial stem cells.

Ivics Z, Izsvák Z, Medrano G, Chapman KM, Hamra FK Nat Protoc 2011 Oct 6 10 1521-35

Foxo1 is required in mouse spermatogonial stem cells for their maintenance and the initiation of spermatogenesis.

Goertz MJ, Wu Z, Gallardo TD, Hamra FK, Castrillon DH J. Clin. Invest. 2011 Sep 121 9 3456-66

Results 1-10 of 22

Professional Associations/Affiliations

  • American Society for Andrology (2008)
  • Society for the Study of Reproduction (2008)