The overall hypothesis addressed by the proposed work is that the Ca- regulatory/cell growth peptide, parathyroid hormone-related protein (PTHrP), plays important regulatory cells in the gut and liver. The major thrust is to identify and elucidate molecular mechanisms by which PTHrP functions in gut epithelium and hepatocytes to regulate cell growth and turnover.
Specific aim 1 will utilize GI and liver cells treated with exogenous PTHrP analogs or stably transfected with PTHrP cDNA in a sense or antisense or antisense orientation to study mechanisms and modes of action or PTHrP on cell proliferation and cell death (apoptosis). PTHrP cDNA bearing mutations of the peptide's nuclear targeting sequences, as well as neutralizing PTHrP antisera will be employed by discern whether the protein acts in an intracrine fashion by targeting directly to the nucleus or largely by autocrine/paracrine mechanisms following secretion. Mechanisms underlying changes in cell proliferation or cell death will be examined systematically using a variety of methods already in hand.
Specific aim 2 will extend the vitro findings in aim 1 to the intact animal by establishing transgenic mice that over- or under- express PTHrP in the gut and liver. The animals will receive a transgene construct containing the coding sequence for full-length PTHrP driven by a fatty acid binding protein promoter sequence that targets protein expression to the intestinal epithelium and liver. Studies of peptide expression using histological, immunoassay, and RNA detection methods will be coupled to studies assessing biological functioning of the gut and complex context of the whole organism.
Specific aim 3 is designed to express sufficient amounts of recombinant PTHrP to enable study of its 3D structure. An intein-mediated purification of expressed protein using an affinity chitin-binding column will be used to generate the mg quantities of protein required for 1D, 2D, and eventual 3D analysis. The overall goal is to understand the fundamental structure of the peptide and relate that to findings from eventual studies of its interaction with receptor proteins that mediate its effects or with enzymes that process it. Overall the work will provide insight into the fundamental actions of PTHrP in the gut and liver and should enhance our understanding of the important roles this protein plays in health and disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Program Projects (P01)
Project #
5P01DK035608-17
Application #
6587852
Study Section
Special Emphasis Panel (ZDK1)
Project Start
2002-04-01
Project End
2003-03-31
Budget Start
Budget End
Support Year
17
Fiscal Year
2002
Total Cost
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Type
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555
Bhatia, Vandanajay; Cao, Yanna; Ko, Tien C et al. (2016) Parathyroid Hormone-Related Protein Interacts With the Transforming Growth Factor-?/Bone Morphogenetic Protein-2/Gremlin Signaling Pathway to Regulate Proinflammatory and Profibrotic Mediators in Pancreatic Acinar and Stellate Cells. Pancreas 45:659-70
Staloch, Dustin; Gao, Xuxia; Liu, Ka et al. (2015) Gremlin is a key pro-fibrogenic factor in chronic pancreatitis. J Mol Med (Berl) 93:1085-1093
Mrazek, Amy A; Porro, Laura J; Bhatia, Vandanajay et al. (2015) Apigenin inhibits pancreatic stellate cell activity in pancreatitis. J Surg Res 196:8-16
Gao, Xuxia; Cao, Yanna; Staloch, Dustin A et al. (2014) Bone morphogenetic protein signaling protects against cerulein-induced pancreatic fibrosis. PLoS One 9:e89114
Bhatia, Vandanajay; Rastellini, Cristiana; Han, Song et al. (2014) Acinar cell-specific knockout of the PTHrP gene decreases the proinflammatory and profibrotic responses in pancreatitis. Am J Physiol Gastrointest Liver Physiol 307:G533-49
Gao, Xuxia; Cao, Yanna; Yang, Wenli et al. (2013) BMP2 inhibits TGF-?-induced pancreatic stellate cell activation and extracellular matrix formation. Am J Physiol Gastrointest Liver Physiol 304:G804-13
Deng, Xiyun; Cao, Yanna; Liu, Yan et al. (2013) Overexpression of Evi-1 oncoprotein represses TGF-? signaling in colorectal cancer. Mol Carcinog 52:255-264
Cao, Yanna; Zhang, Weili; Gao, Xuxia et al. (2013) PTHrP is a novel mediator for TGF-?-induced apoptosis. Regul Pept 184:40-6
Cao, Yanna; Yang, Wenli; Tyler, Matthew A et al. (2013) Noggin attenuates cerulein-induced acute pancreatitis and impaired autophagy. Pancreas 42:301-7
Okamura, Daiki; Starr, Marlene E; Lee, Eun Y et al. (2012) Age-dependent vulnerability to experimental acute pancreatitis is associated with increased systemic inflammation and thrombosis. Aging Cell 11:760-9

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