Patrick M Viatour, Pharm.D, PhD

faculty photo
Assistant Professor of Pathology and Laboratory Medicine
Department: Pathology and Laboratory Medicine
Graduate Group Affiliations

Contact information
Children's Hospital of Philadelphia
Colket Translational Research Building, Rm 4064
3501 Civic Center Blvd
Philadelphia, PA 19104
Office: 267-425-3004
Education:
BS (Pharmacy)
University of Liege, Belgium, 1998.
Master (of Science)
University of Liege, Belgium, 1999.
PhD
University of Liege, Belgium, 2004.
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Description of Research Expertise

Keywords:
Hematopoietic Stem Cell Biology
Liver Stem/Progenitor Cell Biology
Retinoblastoma and the Rb pathway

Research Overview:
The laboratory is interested in the regulation of stem cells activity in physiological and pathological contexts, and we have chosen the hematopoietic compartment and the liver as working models.
We study the mechanisms that regulate various aspects of stem cell biology, including cell cycle regulation, the decision to self-renew or differentiate into more mature cells, and interactions between stem cells and their niches. While hematopoietic stem cells are well described and serve as a paradigm to study stem cells from other biological systems, the liver stem/progenitor cell compartment is poorly characterized, and the contribution of stem cells to liver development and homeostasis is a subject of intense debate. We are developing several approaches, including new lines of transgenesis, to identify populations of stem and progenitor cells throughout different steps of development (from embryogenesis to adult liver) and we intend to characterize these populations, in order to identify a spatio-temporal hierarchy between them and understand their contribution to liver biology.
In addition, we investigate the mechanisms that promote the aberrant activity of stem cells, and the development of various types of cancer that originates from the stem cell compartment. In particular, we are developing an important research effort to characterize the role of the Rb pathway in the regulation of stem cells activity. The Rb family of genes includes Rb (the first identified tumor suppressor gene), p130 and p107, and is a central component of the Rb pathway. Genetic or epigenetic events targeting various components of the Rb pathway have been identified in the vast majority of cancers of diverse origin, and an important consequence of these events is the functional inactivation of the Rb family of proteins. However, mechanisms of tumorigenesis upon functional alteration of the Rb pathway are poorly understood, and we have recently shown that the stem cell compartment is particularly sensitive to loss of Rb family of genes. We have developed several mouse models to investigate the role of the Rb family of genes in the control of hematopoietic and liver stem cells activity, and we use a combination of bioinformatic analysis, in vitro, ex vivo and in vivo approaches to characterize the molecular and cellular mechanisms of tumorigenesis upon alteration of the Rb pathway in the liver (hepatocellular carcinoma) and the blood (myeloid disorders).
Graduate students interested in rotating in the lab should contact Dr. Viatour for additional information on the research projects currently developed.

Lab members:
Amy Tarangelo, Research Assistant
Nathanael Lo, Research Assistant
Eunsun Kim, Graduate Student
Pichai Raman, Bioinformatician
Kathryn Wurges, Administrative Assistant

Selected Publications

Garfin P, Min D, Bryson J, Serwold T, Edris B, Blackburn CC, Richie E, Weinberg K, Manley N, Sage J and Viatour P: Inactivation of the RB family prevents thymus involution and promotes thymic function by direct control of Foxn1 expression. Journal of Experimental Medicine in press, 2013.

Viatour P and Sage J: Newly identified aspects of tumor suppression by Rb. Disease Models and Mechanisms 4 (5), 2011.

Viatour P, Saddic L, Elhmer U, Lin C, Dorrell C, Andersen JB, Schaffer B, Ostermeier A, Vogel H, Sylvester KG, Thorgeirsson SS, Grompe M, and Sage J.: Notch signaling suppresses hepatocellular carcinoma initiated from mouse adult liver progenitors following inactivation of the Rb family. Journal of Experimental Medicine 208 (10): 1963-76, 2011.

Wirt SE, Adler AS, Gebala V, Weimann JM, Schaffer BE, Saddic LA, Viatour P, Vogel H, Chang HY, Meissner A, Sage J.: G1 arrest and differentiation can occur independently of Rb family function. J Cell Biol. 191(4): 809-25, 2010.

Viatour P, Somervaille TC, Venkatasubrahmanyam S, Kogan S, McLaughlin ME, Weissman IL, Butte AJ, Passegue E and Sage J.: Hematopoietic stem cell quiescence is maintained by compound contributions of the retinoblastoma gene family. Cell Stem Cell 3(4): 416-428, 2008.

Kotake Y, Cao R, Viatour P, Sage J, Zhang Y, Xiong Y.: pRb family proteins are required for H3K27 trimethylation and Polycomb repression complexes binding to and silencing p16INK4alpha tumor suppressor gene. Genes and Development 21(1): 49-54, 2007.

Viatour P, Merville MP, Bours V and Chariot A.: Phosphorylation of NF-κB/IκB proteins: implications in cancer and inflammation. Trends in Biochemical Sciences 30(1): 43-52, 2005.

Viatour P, Dejardin E, Warnier M, Lair F, Claudio E, Bureau F, Marine JC, Merville MP, Maurer U, Green DR, Piette J, Siebenlist U, Bours V and Chariot A.: GSK3-mediated BCL-3 phosphorylation modulates its degradation and its oncogenicity. Molecular Cell 16(1): 35-45, 2004.

Viatour P, Bentires-Alj M, Chariot A, Deregowski V, de Leval L, Merville MP and Bours V.: NF-kappaB2/p100 induces Bcl-2 expression. Leukemia 17(7): 1349-1356, 2003.

Viatour P, Legrand-Poels S, Van Lint C, Warnier M, Merville MP, Gielen J, Piette J, Bours V and Chariot A.: Cytoplasmic IkappaBalpha increases NF-kappaB independent transcription through binding to HDAC1 and HDAC3. Journal of Biological Chemistry 278(47): 46541-46548, 2003.

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Last updated: 01/13/2014
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