Understanding the mechanisms regulating myometrial intracellular free Ca (Cai) dynamics is critical to understanding the control of myometrial activity. Signal-regulated calcium entry (also called capacitative entry) is broadly defined here to include both receptor- and store-operated entry. This pathway has been implicated in regulation of membrane potential and tone in smooth muscle and may play a role in the regulation of myometrial contractile activity by hormones, growth factors and cytokines. Hence regulated calcium entry may participate in control of uterine contractile activity during pregnancy and parturition. We found that rat and human myometrial cells respond to more than one signal-regulated calcium stimulus and express a number of TrpC mRNAs and proteins implicated in this type of calcium entry. The overall goal of this study is to understand the role of TrpC proteins in the regulation of myometrial Cai dynamics and control of contractile activity.
Aim 1 will determine the relative importance of signal-regulated Ca entry in the control of myometrial Cai dynamics, measured by fluorescence imaging, and to contractile activity in uterine strips.
Aim 2 will delineate the contribution of specific TrpC proteins to signal-regulated calcium entry and Cai dynamics in human myometrial cells. The effects of both overexpression and suppression of TrpC expression on myometrial cell Cai dynamics will be determined and linked to specific responses.
Aim 3 will examine the regulation of TrpC expression and of signal-regulated Ca entry by other signaling pathways in myometrium. These studies will utilize Q-RT-PCR, immunoblot and Ca imaging approaches in human myometrial cells and the pregnant rat model.
Aim 4 will examine the influence of TrpC subtype expression on TrpC association with myometrial plasma membrane and possible effects of signal-regulated Ca entry on activity of other membrane proteins. These studies will use scanning confocal microscopy and subcellular fractionation approaches. These studies promise new insights into the role of this tightly regulated calcium entry mechanism in the control of myometrial Cai dynamics and myometrial contraction and may lead to design of new approaches for controlling myometrial activity during pregnancy and labor.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD038970-08
Application #
7467919
Study Section
Pregnancy and Neonatology Study Section (PN)
Program Officer
Ilekis, John V
Project Start
2000-06-01
Project End
2011-08-31
Budget Start
2008-09-01
Budget End
2011-08-31
Support Year
8
Fiscal Year
2008
Total Cost
$176,162
Indirect Cost
Name
Colorado State University-Fort Collins
Department
Veterinary Sciences
Type
Schools of Veterinary Medicine
DUNS #
785979618
City
Fort Collins
State
CO
Country
United States
Zip Code
80523
Murtazina, Dilyara A; Chung, Daesuk; Ulloa, Aida et al. (2011) TRPC1, STIM1, and ORAI influence signal-regulated intracellular and endoplasmic reticulum calcium dynamics in human myometrial cells. Biol Reprod 85:315-26
Chung, Daesuk; Kim, Yoon-Sun; Phillips, Jennifer N et al. (2010) Attenuation of canonical transient receptor potential-like channel 6 expression specifically reduces the diacylglycerol-mediated increase in intracellular calcium in human myometrial cells. Endocrinology 151:406-16
Ulloa, Aida; Gonzales, Albert L; Zhong, Miao et al. (2009) Reduction in TRPC4 expression specifically attenuates G-protein coupled receptor-stimulated increases in intracellular calcium in human myometrial cells. Cell Calcium 46:73-84
Sanborn, Barbara M (2007) Hormonal signaling and signal pathway crosstalk in the control of myometrial calcium dynamics. Semin Cell Dev Biol 18:305-14
Ku, Chun-Ying; Babich, Lidiya; Word, R Ann et al. (2006) Expression of transient receptor channel proteins in human fundal myometrium in pregnancy. J Soc Gynecol Investig 13:217-25
Sanborn, Barbara M; Ku, Chun-Ying; Shlykov, Sergiy et al. (2005) Molecular signaling through G-protein-coupled receptors and the control of intracellular calcium in myometrium. J Soc Gynecol Investig 12:479-87
Babich, Lidiya G; Ku, Chun-Ying; Young, Hays W J et al. (2004) Expression of capacitative calcium TrpC proteins in rat myometrium during pregnancy. Biol Reprod 70:919-24
Shlykov, Sergiy G; Sanborn, Barbara M (2004) Stimulation of intracellular Ca2+ oscillations by diacylglycerol in human myometrial cells. Cell Calcium 36:157-64
Shlykov, Sergiy G; Yang, Ming; Alcorn, Joseph L et al. (2003) Capacitative cation entry in human myometrial cells and augmentation by hTrpC3 overexpression. Biol Reprod 69:647-55
Yang, Ming; Gupta, Anupma; Shlykov, Sergiy G et al. (2002) Multiple Trp isoforms implicated in capacitative calcium entry are expressed in human pregnant myometrium and myometrial cells. Biol Reprod 67:988-94