Abstract

The long-term objective of this research program is to understand the molecular mechanisms involved in the regulation of intracellular cholesterol metabolism. Based on results presented in PRELIMINARY STUDIES, in the forthcoming granting period the focus will be on studying the mechanisms of cellular cholesterol trafficking and storage processes in mammalian cells.
Two Specific Aims are proposed:
Specific Aim 1 : To test the hypothesis that the trans-Golgi network (TGN) serves as a key organelle for transporting low-density lipoprotein (LDL)-derived cholesterol from the endosomes to the plasma membrane/endoplasmic reticulum (ER).
Sub Aim 1. 1: To test the possibility that membranes containing the Syntaxin 6/Syntaxin 16/Vti1a complex play a key role in LDL-CHOL trafficking.
Sub Aim 1. 2: To test the possibility that the v-SNAREs Vamp4/Vamp3 may contribute to LDL- CHOL transport between the NPC1 compartment and the Syntaxin 6-rich compartment.
Sub Aim 1. 3: To biochemically characterize various membrane compartments associated with 3H-CHOL derived from LDL.
Specific Aim 2 : To examine the functional and biochemical characteristics of caveolae in the ER.
Sub Aim 2. 1: To examine the functional characteristics of the ER caveolae in intact cells and in vitro.
Sub Aim 2. 2: To examine the biochemical characteristics of the ER caveolae in intact cells and in vitro. LDL is the major cholesterol carrier in the blood. High LDL is a risk factor for atherosclerosis, which is a major cause of heart disease. The outcome of research described in the current application will bring new knowledge about the intracellular transport and storage processes of LDL-derived cholesterol, and may help develop new approaches for reducing the amount of LDL-derived cholesterol stored in tissues.

Public Health Relevance

Low-density lipoprotein (LDL) is the major cholesterol carrier in the blood. High LDL is a risk factor for atherosclerosis, which is a major cause of heart disease. The outcome of research described in the current application will bring new knowledge about the transport and storage process of LDL-derived cholesterol, and may help develop new approaches for reducing the amount of LDL-derived cholesterol stored in tissues.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL036709-27
Application #
8277279
Study Section
Special Emphasis Panel (ZRG1-EMNR-G (02))
Program Officer
Liu, Lijuan
Project Start
1989-07-01
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2014-05-31
Support Year
27
Fiscal Year
2012
Total Cost
$451,349
Indirect Cost
$169,080

  Institution

Name
Dartmouth College
Department
Biochemistry
Type
Schools of Medicine
DUNS #
041027822
City
Hanover
State
NH
Country
United States
Zip Code
03755

  Publications

Poirier, Steve; Mayer, Gaétan; Murphy, Stephanie R et al. (2013) The cytosolic adaptor AP-1A is essential for the trafficking and function of Niemann-Pick type C proteins. Traffic 14:458-69
Lu, Ming; Hu, Xi-Han; Li, Qin et al. (2013) A specific cholesterol metabolic pathway is established in a subset of HCCs for tumor growth. J Mol Cell Biol 5:404-15
Maue, Robert A; Burgess, Robert W; Wang, Bing et al. (2012) A novel mouse model of Niemann-Pick type C disease carrying a D1005G-Npc1 mutation comparable to commonly observed human mutations. Hum Mol Genet 21:730-50
Sakashita, Naomi; Chang, Catherine C Y; Lei, Xiaofeng et al. (2010) Cholesterol loading in macrophages stimulates formation of ER-derived vesicles with elevated ACAT1 activity. J Lipid Res 51:1263-72
Chen, Jia; Zhao, Xiao-Nan; Yang, Li et al. (2008) RNA secondary structures located in the interchromosomal region of human ACAT1 chimeric mRNA are required to produce the 56-kDa isoform. Cell Res 18:921-36
Reid, Patrick C; Lin, Song; Vanier, Marie T et al. (2008) Partial blockage of sterol biosynthesis with a squalene synthase inhibitor in early postnatal Niemann-Pick type C npcnih null mice brains reduces neuronal cholesterol accumulation, abrogates astrogliosis, but may inhibit myelin maturation. J Neurosci Methods 168:15-25
Urano, Yasuomi; Watanabe, Hiroshi; Murphy, Stephanie R et al. (2008) Transport of LDL-derived cholesterol from the NPC1 compartment to the ER involves the trans-Golgi network and the SNARE protein complex. Proc Natl Acad Sci U S A 105:16513-8
Yamauchi, Yoshio; Reid, Patrick C; Sperry, Jeffrey B et al. (2007) Plasma membrane rafts complete cholesterol synthesis by participating in retrograde movement of precursor sterols. J Biol Chem 282:34994-5004
Sugii, Shigeki; Lin, Song; Ohgami, Nobutaka et al. (2006) Roles of endogenously synthesized sterols in the endocytic pathway. J Biol Chem 281:23191-206
Chang, Ta-Yuan; Reid, Patrick C; Sugii, Shigeki et al. (2005) Niemann-Pick type C disease and intracellular cholesterol trafficking. J Biol Chem 280:20917-20

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