CCN5 Expression, Localization, and Function in Smooth Muscle Cells.

摘要

CCN5, a member of the CCN family of growth factors, inhibits the proliferation and migration of smooth muscle cells in cell culture and animal models. Expressed in both embryonic and adult tissues, CCN5 exhibits a matricellular localization pattern characteristic of secreted proteins that are closely associated with the cell surface. In addition to this observed expression pattern, immunohistochemical evidence suggests the presence of nuclear CCN5 in some cells. In chapter two of this thesis I show that CCN5 is a nuclear protein through immunohistochemistry, confocal imaging, and cell fractionation. Using site directed mutagenesis we confirm that the identified putative nuclear localization signal in the VWC domain of rat CCN5 is not necessary for nuclear localization.;The third chapter of this thesis explores the effect of CCN5 on cell cycle proteins in myometrial smooth muscle cells (SMC). Preliminary microarray data suggests that CCN5 increases p27 and p21 mRNA and decreases cyclin D1 mRNA expression in vascular SMC. Forced expression of CCN5 in vascular SMC released from growth arrest delays cyclin D1 protein expression. In contrast to these observations made in vascular SMC, I found that CCN5 had no effect on cyclin D1, p21, or p27 in myometrial SMC suggesting that CCN5 expression may affect proliferation of vascular and myometrial SMC by different mechanisms.;Observations from both cell culture and clinical studies suggest that the selective estrogen receptor modulators (SERMs) tamoxifen and raloxifene and the progesterone antagonist mifepristone may be effective therapeutics for uterine leiomyoma. Chapter 4 of this thesis evaluates the anti-proliferative effects of tamoxifen, raloxifene, and mifepristone on two patient samples of human uterine myometrial and leiomyoma SMC. Although raloxifene and tamoxifen had no affect on uterine SMC proliferation, mifepristone inhibited proliferation of leiomyoma SMC from one patient sample.;Overall the results presented in this thesis provide new insights into the localization, expression, and function of CCN5 in vascular and myometrial SMC.