The role of transforming growth factor beta in cervical remodeling within the rat cervix

Progesterone modulates integrin {alpha}2 (ITGA2) and {alpha}11 (ITGA11) in the pregnant cervix

OBJECTIVE

Fibrillar collagen in the cervical extracellular matrix (ECM) is the predominant component providing mechanical support. Cellular integrins contribute to structural integrity by cross-linking ECM components. We investigated the expression of collagen-binding integrins in the normal rat gestation and after treatment with mifepristone to determine whether integrin modulation is involved in changes in tissue resistance.

STUDY DESIGN

Cervical tissue was harvested from nonpregnant and timed pregnant Sprague-Dawley rats. Normal gestational expression was evaluated in nonpregnant and timed pregnant tissue on days 12, 16, 18, 20, 21 and 22. Progesterone inhibition was induced with 3 mg mifepristone administered on day 15. Primary rat cervical stromal (RCS) cell cultures were generated from nonpregnant rats using tissue explants. The effects of progesterone environment on RCS cells were evaluated in the presence and absence of various inhibitors. Protein expression and signaling pathways were evaluated by Western blot.

RESULTS

Integrin α2 (ITGA2) expression increased over gestation, peaking at the end of gestation (analysis of variance [ANOVA] P < .01). Integrin α11 (ITGA11) expression increased through mid-gestation, peaking on day 18 and decreasing through day 22 (ANOVA P < .001). Progesterone increased the expression of ITGA11 and phosphorylated focal adhesion kinase ([pFAK] P < .002). Mifepristone blocked these effects in vitro. Mifepristone increased ITGA2 and phosphorylated extracellular signal-regulated kinases 1 and 2 (pERK1/2) in vivo and in vitro. Mifepristone-induced upregulation of ITGA2 was abrogated by inhibition of ERK1/2.

CONCLUSION

Progesterone/progesterone withdrawal is involved in regulating the expression of collagen-binding integrins. These changes differ among the collagen-binding integrins. Mitogen-activated protein kinase (MAPK) signaling is involved in regulating some of these integrins.

The transcriptome of cervical ripening in human pregnancy before the onset of labor at term: identification of novel molecular functions involved in this process

OBJECTIVE

The aim of this study was to identify changes in the cervical transcriptome in the human uterine cervix as a function of ripening before the onset of labor.

STUDY DESIGN

Human cervical tissue was obtained from women at term not in labor with ripe (n = 11) and unripe (n = 11) cervices and profiled using Affymetrix GeneChip HGU133Plus2.0 arrays. Gene expression was analyzed using a moderated t-test (False Discovery Rate 5%). Gene ontology and pathway analysis were performed. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used for confirmation of selected differentially expressed genes.

RESULTS

(1) Ninety-one genes were differentially expressed between ripe and unripe groups. (2) Cervical ripening was associated with enrichment of specific biological processes (e.g. cell adhesion, regulation of anatomical structure), pathways and 11 molecular functions (e.g. extracelluar matrix (ECM)-structural constituent, protein binding, glycosaminoglycan binding). (3) qRT-PCR confirmed that 9 of 11 tested differentially expressed genes (determined by microarray) were upregulated in a ripe cervix (e.g. MYOCD, VCAN, THBS1, COL5A1). (4) Twenty-three additional genes related to ECM metabolism and adhesion molecules were differentially regulated (by qRT-PCR) in ripe cervices.

CONCLUSION

(1) This is the first description of the changes in the human cervical transcriptome with ripening before the onset of labor. (2) Biological processes, pathways and molecular functions were identified with the use of this unbiased approach. (3) In contrast to cervical dilation after term labor, inflammation-related genes did not emerge as differentially regulated with cervical ripening. (4) Myocardin was identified as a novel gene upregulated in human cervical ripening.