The long-term goal of our studies is to understand the role of biliary epithelium in the repair and regeneration of the liver after damage. Inherited cholangiopathies with identified genetic defects serve as model diseases to elucidate the fundamental pathophysiological mechanisms. The previously funded proposal focused on polycystic liver disease associated to Adult Dominant Polycystic Kidney Disease (PLD-ADPKD) as a paradigm for the role of angiogenic signaling in biliary diseases. We uncovered mechanisms that may be relevant for the pathogenesis of other congenital and acquired liver diseases. In fact, using mice models with inducible defects of polycystins, we found that: 1) the cystic epithelium produces VEGF and expresses its cognate receptor VEGFR2;2) VEGF-mediated stimulation of VEGFR2 results in increased ERK1/2-dependent proliferation of the cystic epithelium, 3) PC2-defective cystic cholangiocytes, altered cellular Ca2+ homeostasis and a cAMP- dependent increase in PKA/Ras/Raf/ERK signaling results in mTOR/HIF-1?-mediated stimulation of VEGF production, 4) in response to stimuli able to deplete ER Ca2+ stores, PC2 participates in store-operated Ca2+ entry (SOCE);5) if PC2 is defective, an alternative pathway is activated (store-operated cAMP production - SOcAMP), leading to an inappropriate overproduction of cAMP;6) VEGF/VEGFR2 play a key role on cyst growth and expansion through paracrine effects on pericystic vascular cells, and autocrine stimulation of the cystic epithelium proliferation. These findings are the basis of this new proposal which main hypothesis is that the mechanism linking PC2 to VEGF secretion and VEGFR2 expression identified in PLD-ADPKD is of general relevance in biliary pathophysiology. We will address this hypothesis through three specific aims: 1) to better understand the interactions between PC2 function store-operated Ca2+ entry and inappropriate production of cAMP, 2) to study if PC2 expression in WT cholangiocytes can be modulated by cell stressors, thereby reproducing the changes seen in PC2-defective cells;3) to study the mechanisms leading to VEGFR2 expression in cystic and reactive cholangiocytes, and to elucidate the role of VEGF in the branching morphogenesis of the biliary epithelium during liver repair. These studies will address the novel idea that PC2 play a pivotal role in the regulation of cholangiocyte response to biliary damage acquired cholangiopathies, and that VEGF secreted by reactive cholangiocytes is a major factor in liver repair. Furthermore, our studies will increase understanding of VEGF/VEGFR2 signaling in epithelia and will address a fundamental mechanism in congenital and acquired cholangiopathies. Understanding the pathophysiology of cholangiopathies is a fundamental step for preserving liver function and prolonging the survival of patients

Public Health Relevance

Cholangiopathies are a group of genetic and acquired liver diseases responsible for significant morbidity and mortality among liver patients. In this proposal we will test the novel idea that Polycystin-2 (PC2), the protein mutated in ADPKD, can be modulated in response to biliary damage/repair and stimulate reparative VEGF secretion and VEGFR2 expression. Understanding of VEGF/VEGFR2 signaling in epithelia addresses a fundamental mechanism in congenital and acquired cholangiopathies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK079005-06
Application #
8629435
Study Section
Hepatobiliary Pathophysiology Study Section (HBPP)
Program Officer
Doo, Edward
Project Start
2007-07-01
Project End
2018-06-30
Budget Start
2013-09-18
Budget End
2014-06-30
Support Year
6
Fiscal Year
2013
Total Cost
$362,138
Indirect Cost
$144,638
Name
Yale University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Cadamuro, Massimiliano; Spagnuolo, Gaia; Sambado, Luisa et al. (2016) Low-Dose Paclitaxel Reduces S100A4 Nuclear Import to Inhibit Invasion and Hematogenous Metastasis of Cholangiocarcinoma. Cancer Res 76:4775-84
Spirli, Carlo; Mariotti, Valeria; Villani, Ambra et al. (2016) Adenylyl cyclase 5 links changes in calcium homeostasis to cAMP-dependent cyst growth in polycystic liver disease. J Hepatol :
Locatelli, Luigi; Cadamuro, Massimiliano; Spirlì, Carlo et al. (2016) Macrophage recruitment by fibrocystin-defective biliary epithelial cells promotes portal fibrosis in congenital hepatic fibrosis. Hepatology 63:965-82
Geisler, Fabian; Strazzabosco, Mario (2015) Emerging roles of Notch signaling in liver disease. Hepatology 61:382-92
Scirpo, Roberto; Fiorotto, Romina; Villani, Ambra et al. (2015) Stimulation of nuclear receptor peroxisome proliferator-activated receptor-γ limits NF-κB-dependent inflammation in mouse cystic fibrosis biliary epithelium. Hepatology 62:1551-62
Morton, Stuart Duncan; Cadamuro, Massimiliano; Brivio, Simone et al. (2015) Leukemia inhibitory factor protects cholangiocarcinoma cells from drug-induced apoptosis via a PI3K/AKT-dependent Mcl-1 activation. Oncotarget 6:26052-64
Spirli, Carlo; Villani, Ambra; Mariotti, Valeria et al. (2015) Posttranslational regulation of polycystin-2 protein expression as a novel mechanism of cholangiocyte reaction and repair from biliary damage. Hepatology 62:1828-39
Bonato, Giulia; Cristoferi, Laura; Strazzabosco, Mario et al. (2015) Malignancies in Primary Sclerosing Cholangitis--A Continuing Threat. Dig Dis 33 Suppl 2:140-8
Brivio, Simone; Cadamuro, Massimiliano; Fabris, Luca et al. (2015) Epithelial-to-Mesenchymal Transition and Cancer Invasiveness: What Can We Learn from Cholangiocarcinoma? J Clin Med 4:2028-41
Fouassier, Laura; Fiorotto, Romina (2015) Ezrin finds its groove in cholangiocytes. Hepatology 61:1467-70

Showing the most recent 10 out of 33 publications