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Expression of connexin-43 in human myometrium and leiomyoma
1Department of Obstetrics and Gynecology, School of Medicine, State University of New York at Stony Brook 11794-8091.
Insights
Human leiomyoma cells express connexin-43 (Cx43) gap junctions, unlike normal myometrial cells. Cx43 levels in leiomyomas are higher and influenced by steroid hormones, suggesting a role in uterine fibroid development.
Area of Science:
- Cell biology
- Reproductive medicine
- Molecular biology
Background:
- Uterine leiomyomas, also known as fibroids, are common benign tumors.
- Connexin-43 (Cx43) is a key protein in gap junctions, crucial for cell-to-cell communication.
- The role of Cx43 in leiomyoma development is not fully understood.
Purpose of the Study:
- To investigate the expression of connexin-43 (Cx43) in human leiomyomas and compare it with autologous myometrium.
- To analyze the regulation of Cx43 by steroid hormones in leiomyoma and myometrial cells.
Main Methods:
- Indirect immunofluorescence was employed to detect Cx43 gap junctions in tissue and cell cultures.
- Immunoblot and Northern analyses were performed to quantify Cx43 protein and messenger RNA (mRNA) levels.
- Primary cultures of myometrial and leiomyoma cells were treated with 17 beta-estradiol and medroxyprogesterone acetate.
Main Results:
- Connexin-43 (Cx43) gap junctions were present in leiomyoma tissue but absent in autologous myometrial tissue.
- Cx43 gap junctions formed spontaneously in primary cultures of both cell types when treated with 17 beta-estradiol.
- Cx43 protein and mRNA levels were generally higher in leiomyoma cells compared to myometrial cells.
- Medroxyprogesterone acetate treatment led to decreased Cx43 mRNA levels in cultured cells.
Conclusions:
- The differential expression of connexin-43 (Cx43) in leiomyoma versus myometrial cells may indicate distinct responses to steroid hormones.
- These findings suggest that Cx43 and its regulation by hormones could play a role in the pathogenesis of uterine fibroids.
Objectives:
The expression of connexin-43 was examined in human leiomyomas and in autologous myometrium.
Study Design:
Indirect immunofluorescence was used to detect connexin-43 gap junctions in myometrial and leiomyoma tissues and in primary cultures. Immunoblot and Northern analyses were used to examine the levels of connexin-43 protein and cx43 messenger ribonucleic acid in primary cultures.
Results:
Connexin-43 gap junctions were detected in leiomyoma tissue from nonpregnant premenopausal women but not in autologous myometrial tissue. Connexin-43 gap junctions form spontaneously in primary cultures of myometrium and leiomyoma in the presence of 17 beta-estradiol. Fluorescent dye injection confirmed that the gap junctions were coupled in the primary cells. Connexin-43 protein and messenger ribonucleic acid levels generally were higher in leiomyoma cells compared with those of autologous myometrial cells. Steady-state levels of cx43 messenger ribonucleic acid decreased with addition of medroxyprogesterone acetate to the cultures.
Conclusions:
Differences in the levels of cx43 expression in leiomyoma and myometrial cells may reflect differences in responses to steroid hormones.