Increased type I collagen in liver fibrosis results primarily from increased production by activated hepatic stellate cells (HSCs). Transcription of the collagen alpha1(I) gene increases 3 fold in activated HSCs compared to quiescent HSCs while the stability of the mRNA increases approximately 20 fold, which results in the 60 fold increased steady-state mRNA level. Collagen alpha1(I) mRNA stability is regulated by its 3' UTR, which binds alpha-CP, and by its stem-loop in the 5' UTR, which interacts with RNA binding proteins in the nucleus and in the cytoplasm. These proteins may also be involved in coordinate translation of alpha1(I) and alpha2(I) mRNAs and stimulation of collagen production by TGF-beta. To understand the posttranscriptional regulation of collagen alpha1(I) gene expression in HSCs, this proposal will study four specific aims: (1). To investigate the mechanisms of translation and degradation of collagen alpha1(I) mRNA. (2). To design molecular decoys that inhibit collagen type I expression in cultured hscs. (3). To evaluate molecular decoys as antifibrotic therapy in an animal model of liver fibrosis (4). To clone and characterize protein factors which bind the 5' stem-loop of the collagen alpaha1(I) mRNA. One of the goals of therapy of liver fibrosis is to prevent excessive accumulation of collagen type I. Elucidation of the mechanisms that regulate expression of collagen type I in hscs at the molecular level is essential for rational drug design. The proposed experiments will provide information about the critical steps in this regulation and about the molecules involved. Cloning of the 5' stem-loop binding proteins will lead to their characterization as potential targets of drug therapy. Molecular decoys that will be developed may be useful for gene therapy of liver fibrosis. Overall, these studies will greatly enhance our knowledge about the biosynthesis of type I collagen.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK059466-04
Application #
6790514
Study Section
General Medicine A Subcommittee 2 (GMA)
Program Officer
Doo, Edward
Project Start
2002-05-15
Project End
2007-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
4
Fiscal Year
2004
Total Cost
$167,934
Indirect Cost
Name
Florida State University
Department
Type
Schools of Medicine
DUNS #
790877419
City
Tallahassee
State
FL
Country
United States
Zip Code
32306
Zhang, Yujie; Stefanovic, Branko (2017) mTORC1 phosphorylates LARP6 to stimulate type I collagen expression. Sci Rep 7:41173
Zhang, Yujie; Stefanovic, Branko (2016) LARP6 Meets Collagen mRNA: Specific Regulation of Type I Collagen Expression. Int J Mol Sci 17:419
Zhang, Yujie; Stefanovic, Branko (2016) Akt mediated phosphorylation of LARP6; critical step in biosynthesis of type I collagen. Sci Rep 6:22597
Wang, Hao; Stefanovic, Branko (2014) Role of LARP6 and nonmuscle myosin in partitioning of collagen mRNAs to the ER membrane. PLoS One 9:e108870
Stefanovic, Lela; Longo, Liam; Zhang, Yujie et al. (2014) Characterization of binding of LARP6 to the 5' stem-loop of collagen mRNAs: implications for synthesis of type I collagen. RNA Biol 11:1386-401
Manojlovic, Zarko; Earwood, Ryan; Kato, Akiko et al. (2014) RFX7 is required for the formation of cilia in the neural tube. Mech Dev 132:28-37
Stefanovic, Branko (2013) RNA protein interactions governing expression of the most abundant protein in human body, type I collagen. Wiley Interdiscip Rev RNA 4:535-45
Manojlovic, Zarko; Blackmon, John; Stefanovic, Branko (2013) Tacrolimus (FK506) prevents early stages of ethanol induced hepatic fibrosis by targeting LARP6 dependent mechanism of collagen synthesis. PLoS One 8:e65897
Vukmirovic, Milica; Manojlovic, Zarko; Stefanovic, Branko (2013) Serine-threonine kinase receptor-associated protein (STRAP) regulates translation of type I collagen mRNAs. Mol Cell Biol 33:3893-906
Manojlovic, Zarko; Stefanovic, Branko (2012) A novel role of RNA helicase A in regulation of translation of type I collagen mRNAs. RNA 18:321-34

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