Studies during the initial funding period have demonstrated that activation of the phosphatidylinositol signaling pathway (PSP) results in cytosolic calcium oscillation (CCO) driven phasic myometrial contractions. The repetitive cytosolic calcium transients are produced by the release of stored intracellular calcium, along with the influx of extracellular calcium. Additional studies have demonstrated that several isoforms of the signal transduction proteins involved in the PSP are expressed in rat myometrial tissue, including five isoforms for phospholipase C (PLC). The physiologic significance of the simultaneous expression of these multiple PLC isoforms in myometrial tissue is yet to be completely defined; however, it appears that different isoforms are necessary to mediate PSP activation via different membrane receptor classes (i.e. G-protein coupled v. tyrosine kinase coupled). The overall goal of the studies being proposed in this revised Competing Continuation Application is to test the hypothesis that one (or both) of the PLC-gamma isoforms expressed in myometrium are required for the generation of phasic contractions in response to activators of tyrosine kinase (TK), including thrombin and platelet activating factor (PAF).
The specific aims are to test the following hypotheses: 1) that pervanadate (a tyrosine phosphatase inhibitor) produces increased PLC- gamma phosphorylation, inositol phosphate (IP) production, the generation of CCOs, and phasic myometrial contractions, 2) that myometrial contractions in response to thrombin are mediated by TK activation, increased PLC-gamma phosphorylation, IP production, and the generation of CCOs, 3) that PAF produces phasic myometrial contractions mediated by TK activation, increased PLC-gamma phosphorylation, IP production, and the generation of CCOs and 4) that one (or both) of the PLC-gamma isoforms are essential for the pervanadate, thrombin and PAF stimulated activation of the PSP and the generation of cytosolic calcium transients. The latter studies will be performed utilizing antisense oligonucleotides for PLC-gamma1 and PLC-gamma2 with primary uterine myocytes cultures. These proposed studies will continue to improve our understanding of the molecular mechanisms underlying myometrial contractions, and ultimately improve our ability to more effectively treat clinically important disturbances of uterine contractile activity, especially premature labor which contributes substantially to the excessive preterm delivery rate in the U.S.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
7R01HD028506-07
Application #
6548646
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Program Officer
Ilekis, John V
Project Start
1994-09-01
Project End
2003-03-31
Budget Start
2001-09-01
Budget End
2002-03-31
Support Year
7
Fiscal Year
2001
Total Cost
$181,305
Indirect Cost
Name
University of Vermont & St Agric College
Department
Obstetrics & Gynecology
Type
Schools of Medicine
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
Phillippe, Mark; Sweet, Leigh M; Bradley, Diana F et al. (2009) Role of nonreceptor protein tyrosine kinases during phospholipase C-gamma 1-related uterine contractions in the rat. Reprod Sci 16:265-73
Phillippe, Mark; Sweet, Leigh M; Engle, Daniel (2007) The role of phospholipase Cgamma1 tyrosine phosphorylation during phasic myometrial contractions. Am J Obstet Gynecol 196:179.e1-7
Phillippe, Mark; Bradley, Diana F; Engle, Daniel et al. (2006) SHP protein tyrosine phosphatase expression in rat uterine tissue. J Soc Gynecol Investig 13:338-42
Chien, Edward K; Sweet, Leigh; Phillippe, Mark et al. (2003) Protease-activated receptor isoform expression in pregnant and nonpregnant rat myometrial tissue. J Soc Gynecol Investig 10:460-8
Phillippe, Mark; Wolff, David; Saunders, Trevania et al. (2002) Intrauterine expression of prothrombin in the sprague-dawley rat. J Soc Gynecol Investig 9:276-81
Phillippe, M; Elovitz, M; Saunders, T (2001) Thrombin-stimulated uterine contractions in the pregnant and nonpregnant rat. J Soc Gynecol Investig 8:260-5
Elovitz, M A; Ascher-Landsberg, J; Saunders, T et al. (2000) The mechanisms underlying the stimulatory effects of thrombin on myometrial smooth muscle. Am J Obstet Gynecol 183:674-81
Elovitz, M A; Saunders, T; Ascher-Landsberg, J et al. (2000) Effects of thrombin on myometrial contractions in vitro and in vivo. Am J Obstet Gynecol 183:799-804
Ascher-Landsberg, J; Saunders, T; Elovitz, M et al. (1999) The effects of 2-aminoethoxydiphenyl borate, a novel inositol 1,4, 5-trisphosphate receptor modulator on myometrial contractions. Biochem Biophys Res Commun 264:979-82
Ascher-Landsberg, J; Saunders, T; Phillippe, M (1999) Tyrosine kinase-mediated activation of cytosolic calcium oscillations and phasic myometrial contractions. J Soc Gynecol Investig 6:240-4

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