The level of cell replacement required to achieve physiological benefit in the treatment of genetic liver disorders depends on which disease is being treated. The threshold can be as low as only 1% in the hemophilias or as high as 50% in urea cycle disorders. Even the low threshold is difficult to achieve with cell therapy or integrating gene transfer vectors required for life-long therapy. Fortunately, the liver is a highly regenerative organ and in mutant backgrounds where genetically normal hepatocytes have a selective advantage, extensive repopulation can be achieved. We first showed in fumarylacetoacetate hydrolase (Fah) deficient mice that cell replacement levels can reach levels of >98% illustrating the concept of "therapeutic liver repopulation".

We are tackling the problem of genetic liver disease from multiple angles, including 1) isolation and characterization of adult liver stem cells (oval cells); 2) propagation of mature hepatocytes by in vivo expansion; 3) studies on the basic biology of hepatocyte mitosis (octaploid division shown at left); 4) generation of hepatocytes from pluripotent stem cells, especially IPSC; 5) development of strategies to correct point mutations in the liver in vivo (gene repair) and 6) development of novel adeno-associated vectors capable of site-specific integration in vivo. We are considered international leaders in liver stem cell biology and hepatocyte biology.

Our lab has had a long-standing interest in the interrelationship between progenitor cells in the liver and the pancreas. In 2001 we showed that cells from the adult pancreas could give rise to hepatocytes in vivo. More recently, we have been focused on converting hepatobiliary cells to the pancreatic endocrine lineage using genetic reprogramming strategies. To facilitate these studies, our lab has developed novel monoclonal antibodies which permit the isolation of all known cell types from the adult liver and pancreas, both human and mouse. These reagents are giving us the opportunity to study highly pure cell populations from these tissues using genomic approaches and leverage these insights for more efficient reprogramming strategies.

Fanconi's anemia (FA) is a genetic disorder that affects multiple stem cells types, particularly hematopoietic stem cells and germline stem cells. Clinically, it is characterized by birth defects, progressive bone marrow failure and/or cancer proneness. FA cells are hypersensitive to DNA cross-linking agents and have an abnormal cell cycle. At least 14 different FA genes have been cloned ( A, B, C, D1, D2, E, F, G, I, J, L, M, N). Importantly, the gene mutated in FA D1 is BRCA2, the breast cancer susceptibility gene. Many details of the biochemical function(s) of the pathway remain unknown. The Grompe Lab cloned a novel Fanconi Anemia gene, FANCD2, which has been shown to link the Fanconi Anemia pathway to BRCA1, involved in familial breast cancer.

This laboratory is interested in the basic defect in FA cells and therapeutic approaches. We have made murine of FA by knocking out FANCC, FANCA and FANCD2. FANCD2 deficient mice mimic several relevant features of human FA, including hematopoietic defects and cancer susceptibility. These animals have been used for genetic studies as well as preclinical therapy. Gene therapy experiments in murine models of FA have been used to demonstrate in vivo selection at the level of hematopoietic stem cells. Recently, the Grompe lab has discovered small molecules to prevent solid tumors in this disease. Our current research is aimed at identifying novel drugs to ameliorate the hematopoietic defects. Towards this end we have developed induced pluripotent stem cells (IPSC) from FA patients and are studying hematopoiesis in FA at the stem cell level.

Liver biology

1. E. Lagasse, H. Connors, M. Al-Dhalimy, M. Reitsma, M. Dohse,L. Osborne, X. Wang, M. Finegold, I. L. Weissman and M. Grompe (2000)" Purified Hematopoietic Stem Cells Can Differentiate to Hepatocytes In Vivo", Nature Medicine 6: 1229-34
2. X. Wang, H. Willenbring, Y. Akkari, Y. Torimaru, M. Foster, M. Al-Dhalimy, E. Lagasse, M. Finegold, S. Olson and M. Grompe (2003) "Cell fusion is the principal source of bone-marrow derived hepatocytes", Nature 422(6934):897-901
3. H. Willenbring, A. S. Bailey, M. Foster, Y, Akkari, C. Dorrell, S. Olson, M. Finegold, W. H. Fleming and  M. Grompe (2004) "Myelomonocytic cells are sufficient for therapeutic cell fusion in liver", Nature Medicine 10(7):744-8
4. H. Willenbring, A. Vogel, A. Rothfuss, S. Eftekhari, M. Al-Dhalimy, M. Finegold and M. Grompe (2008) "Loss of p21 permits carcinogenesis from chronically damaged liver and kidney epithelial cells despite unchecked apoptosis.", Cancer Cell. 2008 Jul 8;14(1):59-67.
5. N. Paulk, K. Wursthorn, Z. Wang, M. Finegold, M. Kay and M. Grompe (2010) "Adeno-associated virus gene repair corrects a mouse model of hereditary tyrosinemia in vivo.", Hepatology 51(4): 1200-8
6. A.W. Duncan, M.H. Taylor, R.D. Hickey, A.E. Hanlon-Newell, M.L. Lenzi, S.B. Olson, M.J. Finegold and M.Grompe (2010) "The ploidy conveyor of mature hepatocytes as a source of genetic variation" Nature. 2010 Oct 7:467(7316):707-10
7. C.Dorrell, L. Erker, J. Schug, J.L. Kopp, P.S. Canaday, A.J. Fox, O. Smirnova, A.W. Duncan, M.J. Finegold, M. Sander, K.H. Kaestner and M. Grompe (2001) "Prospective isolation of a bipotential clonogenic liver progenitor cell in adult mice" Genes & Development 25: 1193-1203

Fanconi Anemia

1. C. Timmers, J. Hejna, C. Reifsteck, L. Lucas, M. Thayer, T. Taniguchi, A. D'Andrea, S. Olson, R.E. Moses and M. Grompe (2001) "Positional cloning of the Fanconi Anemia group D2 gene", Molecular Cell 7: 241-248
2. S. Houghtaling, C. Timmers, M. Noll, S.N. Jones, M. Finegold, S. Meyn and M. Grompe (2003) "Epithelial cancers in Fanconi Anemia D2 (Fancd2) knockout mice", Genes & Development, 7(16):2021-3
3. A. Rothfuss and M. Grompe (2004) "Repair Kinetics of Genomic Interstrand DNA Cross-Links: Evidence for DNA Double-Strand Break-Dependent Activation of the Fanconi Anemia,/BRCA pathway", Molecular and Cellular Biology 24(1): 123-34
4. Q.S. Zhang, L. Eaton, Eric R. Snyder, S. Houghtaling, J.B. Mitchell, M. Finegold, C. Van Waes, and M. Grompe (2008) "Tempol Protects Against Oxidative Damage and Delays Epithelial Tumor Onset in Fanconi Anemia Mice.", Cancer Research 68(5):1601-1608.
5. H.J. van de Vrugt, L. Eaton, A. Hanlon Newell, M. Al-Dhalimy, R.M. Liskay, S.B. Olson and M. Grompe (2009), Embryonic lethality after combined inactivation of Fancd2 and Mlh1 in mice. Cancer Research 69(24):9431-8
6. Q.S. Zhang, L. Marquez-Loza, L. Eaton, A.W. Duncan, D.C. Goldman, P. Anur, K. Watanabe-Smith, R.K. Rathbun, W.H. Fleming, G.C. Banby and M. Grompe (2010) "Fancd2-/- mice have hematopoietic defects that can be partially corrected by resveratrol" Blood. 116(24):5140-8.

Diabetes

1. X. Wang, M. Al-Dhalimy, E. Lagasse, M. Finegold and M. Grompe (2001) "Liver repopulation and correction of metabolic liver disease by transplanted adult mouse pancreatic cells", American Journal of Pathology 158: 571-9
2. C. Dorrell, S.L Abraham, KM Lanxon-Cookson, PS Canaday, PR Streeter and M. Grompe (2008) "Isolation of major pancreatic cell types and long-term culture-initiating cells using novel human surface markers" Stem Cell Research 1(1): 183-94
3. P. Gadue, V. Gouon-Evans, X. Cheng, E. Wandzioch, K.S. Zaret, M. Grompe, P.R. Streeter and G.M. Keller (2009) "The Generation of Monoclonal Antibodies Specific for Cell Surface Molecules Expressed on Early Mouse Endoderm", Stem Cells 27 (9): 103-13
4. C.Dorrell, M.T. Grompe, F.C. Pan, Y. Zhong, P.S. Canaday, L.D. Shultz, D.L. Greiner, C.V. Wright, P.R. Streeter and M. Grompe (2011) "Isolation of mouse pancreatic alpha, beta, duct and acinar populations with cell surface markers.: Molecular and Cellular Endocrinology 339(1-2): 144-50

Craig Dorrell

Craig Dorrell received his B.Sc in Biochemistry and Biotechnology from Carleton University in Ottawa, Canada in 1993 and an M.Sc in Molecular and Medical Genetics from the University of Toronto in 1995. He remained in Toronto but moved to the laboratory of John Dick to study normal and leukemic human hematopoetic stem cells and received a Ph.D in 2003. Since joining the Grompe laboratory he has developed collections of cell type-specific monoclonal antibodies and used these to isolate and characterize cells from the mouse liver and pancreas. His current research focuses on the nature and potential of adult stem/progenitor cells from mouse and human pancreas. These are a potential source of new beta cells for the treatment of Diabetes and may be a critical target in the initiation and maintenance of pancreatic cancer.

Annelise Haft

Annelise is a Research Assistant in the Oregon Stem Cell Center. She serves as the Lead Surgical Technician and DCM liaison for a number of projects in the Grompe Lab, including the Tyrosinemia and Fanconi Anemia studies. She previously worked in the laboratory of Dr. Scott Adams at his company, Veterinary Medicine Research and Development (VMRD), doing various diagnostic assays, and background disease research.  As an undergraduate, she undertook research focusing on the differing metabolic rates of crustaceans and Apodichthys flavidus in aquatic and aerobic environments. Annelise received her Bachelor of Science degree in Biology from the University of Puget Sound in 2008, where she was a Presidential Scholar. She plans to pursue a graduate degree in Animal Behavior and Conservation Biology.