University of Tennessee Health Science Center
The Biochemical Pathway Leading to Lpa Generation Upon Blood Coagulation
Abstract
dc:description.abstract<p>Platelet activation initiates an upsurge in 18:2 and 20:4 lysophosphatidic acid (LPA) production. The biochemical pathway responsible for LPA production during blood clotting is not fully understood. We have purified a phospholipase A<sub>1</sub> (PLA<sub>1</sub>) from thrombin-activated human platelets using sequential chromatographic steps followed by fluorophosphonate‑biotin affinity labeling and proteomics. We identified acyl‑protein thioesterase 1 (aka. lysophospholipase A1, accession code O75608) as a novel PLA<sub>1</sub>. Addition of this recombinant PLA<sub>1</sub> significantly increased the production of <em>sn</em>‑<em>2</em>‑esterified polyunsaturated LPCs and the corresponding LPAs in plasma. We next examined the regioisomeric preference of lysophospholipase D/autotaxin (ATX), which is the subsequent step in LPA production. To prevent acylmigration regioisomers of oleyl‑<em>sn</em>‑glycero‑3‑phosphocholine (LPAF) were synthesized. ATX preferred the <em>sn</em>‑<em>1</em> over the <em>sn</em>‑<em>2</em> regioisomer of LPAF. We propose the following LPA production pathway in blood: 1) Activated platelets secrete PLA<sub>1</sub>. 2) PLA<sub>1</sub>generates a pool of <em>sn‑2 </em>lysophospholipids. 3) These newly generated <em>sn‑2 </em>lysophospholipids undergo acyl migration to yield <em>sn‑1 </em>lysophospholipids, which are the preferred substrates of ATX. 4) ATX cleaves the <em>sn‑1 </em>lysophospholipids to generate <em>sn‑1 </em>LPA species predominant with 18:2 and 20:4 fatty acids.</p>
Degree
thesis:*- Name thesis:degree_name
- Doctor of Philosophy (PhD)
- Level thesis:degree_level
- Dissertation
- Discipline thesis:degree_discipline
- Biomedical Sciences
- Year dc:date.available
- 2011
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Bolen, Alyssa Lynn Jefferson
- Contributors dc:contributor
-
- Gabor J. Tigyi, M.D., Ph.D.
Subjects
dc:subject × 7Identifiers
dc:identifier.*- Repository record dc:identifier
- https://dc.uthsc.edu/dissertations/27
- OAI identifier oai:identifier
- oai:dc.uthsc.edu:dissertations-1027