Angiogenesis is the process whereby new blood vessels sprout from existing vessels and requires that the specialized resident cells lining the vasculature, the endothelial cells (ECs), proliferate, migrate and differentiate spatially and temporally in response to specific signals. Vasculogenesis, on the other hand, has only recently emerged as an alternative mechanism of blood vessel growth in adult tissues and is the result of homing and engraftment of circulating EC precursors (ECPs) of bone marrow origin to areas of neovascularization. Both events are known to occur within the liver vasculature under very different conditions of growth, injury and repair, but the extent of each and the mechanisms by which they proceed in each case is completely unknown. The overall goal of this proposal is to determine the specific growth factor signaling events that induce angiogenic versus vasculogenic blood vessel growth in the context of liver and determine the subsequent microenvironmental milieu that induces EPC recruitment and/or differentiation of the liver-specific sinusoidal endothelial cell (SEC) fenestrated morphotype. Two paradigms of clinically-relevant liver repair allow us to spatially and temporally detail the growth factor signaling events and evaluate sinusoidal ultrastructure and liver-specific SEC function in the rat.
AIM I : Growth factor and microenvironmental interactions will be examined at the sinusoidal surface following 70% partial hepatectomy (PHx) since there is initially extensive hepatocyte proliferation in the absence of EC proliferation until 96 hr post-PHx, resulting in avascular hepatic foci. Subsequent proliferation and infiltration of the SEC into these avascular parenchymal clusters and reestablishment of the normal hepatic architecture provides a well-timed model for evaluating physiological angiogenesis.
AIM II : Angiogenic and vasculogenic events will be examined concurrently using an allogeneic liver transplant model (dual cross strain and female to male transplants, non-GFP to GFP rats) to ascertain the source of SEC (host vs. graft) and determine extent of recipient and donor involvement in SEC engraftment and/or proliferation. Prior to transplantation, livers are stored under cold, ischemic conditions for 18 h, and upon transplantation (warm reperfusion), a majority of the SEC slough off immediately from the sinusoidal surface. Remarkably, within 24 hr, the SEC lining has nearly completely repopulated at least partially from ECPs, but microvascular remodeling, morphological and functional modification occurs over subsequent days. Comparative analysis of these two systems will elucidate both similar and dissimilar growth factor signaling mechanisms and the role of the microenvironment that control these events and potentially lead to optimization of therapies that will reflect the specific requirements for injury based liver neovascularization.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA076541-09
Application #
7187422
Study Section
Metabolic Pathology Study Section (MEP)
Program Officer
Jhappan, Chamelli
Project Start
1998-08-15
Project End
2009-02-28
Budget Start
2007-03-01
Budget End
2008-02-29
Support Year
9
Fiscal Year
2007
Total Cost
$220,307
Indirect Cost
Name
University of Pittsburgh
Department
Physiology
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Robinson, Andria R; Yousefzadeh, Matthew J; Rozgaja, Tania A et al. (2018) Spontaneous DNA damage to the nuclear genome promotes senescence, redox imbalance and aging. Redox Biol 17:259-273
Norris, Callie A; He, Mu; Kang, Liang-I et al. (2014) Synthesis of IL-6 by hepatocytes is a normal response to common hepatic stimuli. PLoS One 9:e96053
Filali, Ebtisam El; Hiralall, Johan K; van Veen, Henk A et al. (2013) Human liver endothelial cells, but not macrovascular or microvascular endothelial cells, engraft in the mouse liver. Cell Transplant 22:1801-11
Tanaka, Yugo; Shigemura, Norihisa; Kawamura, Tomohiro et al. (2012) Profiling molecular changes induced by hydrogen treatment of lung allografts prior to procurement. Biochem Biophys Res Commun 425:873-9
Hang, Ta-Chun; Lauffenburger, Douglas A; Griffith, Linda G et al. (2012) Lipids promote survival, proliferation, and maintenance of differentiation of rat liver sinusoidal endothelial cells in vitro. Am J Physiol Gastrointest Liver Physiol 302:G375-88
Gregg, Siobhán Q; Gutiérrez, Verónica; Robinson, Andria Rasile et al. (2012) A mouse model of accelerated liver aging caused by a defect in DNA repair. Hepatology 55:609-21
Goss, James R; Stolz, Donna Beer; Robinson, Andria Rasile et al. (2011) Premature aging-related peripheral neuropathy in a mouse model of progeria. Mech Ageing Dev 132:437-42
Ikeda, Atsushi; Ueki, Shinya; Nakao, Atsunori et al. (2009) Liver graft exposure to carbon monoxide during cold storage protects sinusoidal endothelial cells and ameliorates reperfusion injury in rats. Liver Transpl 15:1458-68
Straub, Adam C; Klei, Linda R; Stolz, Donna B et al. (2009) Arsenic requires sphingosine-1-phosphate type 1 receptors to induce angiogenic genes and endothelial cell remodeling. Am J Pathol 174:1949-58
Tomiyama, Koji; Murase, Noriko; Stolz, Donna Beer et al. (2008) Characterization of transplanted green fluorescent protein+ bone marrow cells into adipose tissue. Stem Cells 26:330-8

Showing the most recent 10 out of 15 publications