The overall goal of this project is to understand how the native, membrane-bound structures of three eicosanoid-synthesizing enzymes, thromboxane A2 (TXA2) synthase (TXAS), prostaglandin 12(prostacyclin, PGI2) synthase (PGIS), and the inducible microsomal prostaglandin E2 (PGE2) synthase-1 (mPGES-1) influence their enzyme functions and their functional coupling with upstream enzymes, cyclooxygenase-1 (COX-l) and -2 (COX-2) in the biosynthesis of TXA2 (a key pro-thrombotic mediator causing stroke and heart attack), PGI2 (a key anti-thrombotic mediator against stroke and heart attack) and PGE2 (a key proinflammatory mediator). PGIS, mPGES-1 and TXAS share a common substrate, prostaglandin H2 (PGH2), produced by COX-1 or -2, mainly occurring in the endoplasmic reticulum (ER) membrane. Current studies have revealed that PGIS and mPGES-1 seem to be functionally coupled with COX-2, and TXAS is functionally coupled with COX-lin the ER membrane. The mPGES-1 belongs to a family of enzymes with a different primary structure and membrane topology compared to that of PGIS and TXAS, belonging to the P450 family. This has led us to hypothesize that PGIS, TXAS and mPGES-1 have distinct modes of functional coupling with individual COX isoforms and distinct modes of interaction with PGH2 in the ER membrane. Determination of PGH2 movement (presentation) from the COXs to the downstream enzymes, and their physical proximities in the ER membrane are crucial to elucidate the mechanisms of their different functional coupling. Based on the Pl's previous funding, the new Specific Aims are proposed to: a). Identify and compare the structures and key residues in the membrane anchor domains of TXAS, PGIS and mPGES-1 involved in the PGH2 presentation influencing their biosynthesis of TXA2, PGI2 and PGE2 differently; b). Determine the membrane topology and solution structure of mPGES-1 for comparison with PGIS and TXAS; and c). Elucidate the physical proximities between the COXs and PGIS, TXAS or mPGES- 1 to establish the relationship of the physical separations and their functional couplings. The results will be achieved by using integrated biochemical and biophysical approaches; such as, recombinant proteins and high resolution NMR spectroscopy. These studies will provide insight important to understanding the molecular mechanisms in controlling the biosynthesis of PGI2, TXA2 and PGE2, which mediates vascular and inflammatory diseases, and designs of next generation therapeutic strategies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL056712-11
Application #
7111019
Study Section
Physiological Chemistry Study Section (PC)
Program Officer
Rabadan-Diehl, Cristina
Project Start
1996-08-01
Project End
2007-07-31
Budget Start
2006-08-01
Budget End
2007-07-31
Support Year
11
Fiscal Year
2006
Total Cost
$253,769
Indirect Cost
Name
University of Texas Health Science Center Houston
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
800771594
City
Houston
State
TX
Country
United States
Zip Code
77225
Ling, Qing-Lan; Mohite, Anita J; Murdoch, Emma et al. (2018) Creating a mouse model resistant to induced ischemic stroke and cardiovascular damage. Sci Rep 8:1653
Akasaka, Hironari; Thaliachery, Natasha; Zheng, Xianghai et al. (2017) The key residue within the second extracellular loop of human EP3 involved in selectively turning down PGE2- and retaining PGE1-mediated signaling in live cells. Arch Biochem Biophys 616:20-29
Akasaka, Hironari; Ruan, Ke-He (2016) Identification of the two-phase mechanism of arachidonic acid regulating inflammatory prostaglandin E2 biosynthesis by targeting COX-2 and mPGES-1. Arch Biochem Biophys 603:29-37
Akasaka, Hironari; So, Shui-Ping; Ruan, Ke-He (2015) Relationship of the Topological Distances and Activities between mPGES-1 and COX-2 versus COX-1: Implications of the Different Post-Translational Endoplasmic Reticulum Organizations of COX-1 and COX-2. Biochemistry 54:3707-15
Vollert, Craig; Ohia, Odochi; Akasaka, Hironari et al. (2014) Elevated prostacyclin biosynthesis in mice impacts memory and anxiety-like behavior. Behav Brain Res 258:138-44
Ruan, Ke-He; Mohite, Anita J; So, Shui-Ping (2013) Resistant to thrombosis, induced stroke and heart arrest by incorporation of a single gene of PGI2-synthesizing COX-1-PGIS in vivo: Implication against human heart disease. Int J Cardiol 168:2960-1
Lin, Haocheng; Yuan, Jiuhong; Ruan, Ke-He et al. (2013) COX-2-10aa-PGIS gene therapy improves erectile function in rats after cavernous nerve injury. J Sex Med 10:1476-87
Ruan, Ke-He; Mohite, Anita; So, Shui-Ping et al. (2013) Establishing novel prostacyclin-synthesizing cells with therapeutic potential against heart diseases. Int J Cardiol 163:163-9
Chillar, Annirudha; So, Shui-Ping; Ruan, Cheng-Huai et al. (2011) A profile of NSAID-targeted arachidonic acid metabolisms in human embryonic stem cells (hESCs): implication of the negative effects of NSAIDs on heart tissue regeneration. Int J Cardiol 150:253-9
Ruan, Cheng-Huai; So, Shui-Ping; Ruan, Ke-He (2011) Inducible COX-2 dominates over COX-1 in prostacyclin biosynthesis: mechanisms of COX-2 inhibitor risk to heart disease. Life Sci 88:24-30

Showing the most recent 10 out of 26 publications