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Proteoglycan metabolism in the connective tissue of pregnant and non-pregnant human cervix. An in vitro study.

ABSTRACT: Profound changes occur in the cervix during pregnancy. In particular, the connective tissue is remodelled. To elucidate the mechanisms behind this process, the metabolism of cervical connective tissue was studied using tissue cultures. Cervical biopsies from non-pregnant and pregnant women were incubated with [35S]sulphate. The proteoglycans of the tissue specimens were purified by ion-exchange and gel chromatography and characterized by SDS/PAGE and by enzymic degradation. In the non-pregnant cervix, the incorporation of [35S]sulphate into the proteoglycans was linear for 48 h. During the first 6 h of incubation the accumulation of chiefly one small labelled proteoglycan (apparent Mr 110,000) substituted with dermatan sulphate was recorded. This is in accordance with the known proteoglycan composition of non-pregnant cervical tissue. In addition, small amounts of two larger radioactive dermatan/chondroitin sulphate proteoglycans (apparent Mr values 220,000 and greater than 500,000) were recorded. After longer periods of incubation the proportion of heparan sulphate proteoglycans increased considerably. The pregnant tissue showed a clearly different composition of labelled proteoglycans. An increased accumulation of the two larger dermatan/chondroitin sulphate proteoglycans was seen in addition to the dominant small dermatan sulphate proteoglycan of the non-pregnant cervix. The rate of accumulation of these two proteoglycans was about 3 times higher in the pregnant tissue, whereas that of the small dermatan sulphate proteoglycan was only increased 2-fold. The fact that the concentration of proteoglycans in the pregnant cervix is approximately one-half of that in the non-pregnant cervix indicates that the turnover of proteoglycans in pregnant cervical tissue is significantly increased. The major effect of this profound change of metabolism was a 50% decrease in proteoglycan content and a 2-fold increased proportion of a dermatan sulphate proteoglycan with an apparent Mr of 220,000.

SUBMITTER: Norman M

PROVIDER: S-EPMC1150081 | biostudies-other | 1991 Apr

REPOSITORIES: biostudies-other

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Project description:The aim of this study was to compare differences in expressions and relationships between key genes involved in extracellular matrix metabolism and tissue cellularity in women with and without pelvic organ prolapse (POP).A total of 80 biopsies (anterior cuff, posterior cuff, and/or leading edge) were obtained from 30 women: n = 10 premenopausal without POP (controls), n = 10 premenopausal with POP, and n = 10 postmenopausal with POP. Quantitative reverse-transcriptase polymerase chain reaction was used to assess gene expression of bone morphogenetic protein 1 (BMP1), collagen types I (COL1) and III (COL3), relaxin family peptide receptor 1 (RXFP1), matrix metallopeptidase 2, and TIMP metallopeptidase inhibitors 2 and 3. Hematoxylin and eosin staining was used to assess cellularity of the connective tissue layer. Kruskal-Wallis test, Mann-Whitney U test, Pearson correlation, or linear regression analyses were used, as appropriate.Bone morphogenetic protein 1 expression was significantly up-regulated in patients with POP compared with controls. Bone morphogenetic protein 1 expression was correlated with COL1 expression in all groups but only correlated with TIMP metallopeptidase inhibitor 3 expression in controls. Similarly, COL3 expression was correlated with RXFP1 expression in women with POP but not in controls. The degree of dependence (slope of the regression line) between COL1 and COL3 expressions was significantly elevated in premenopausal women with POP compared with the other 2 groups. The slopes between COL1-COL3, COL3-matrix metallopeptidase 2, COL1-RXFP1, and COL3-RXFP1 expressions were significantly lower in postmenopausal women compared with premenopausal women with POP. No differences were found in overall tissue cellularity.Bone morphogenetic protein 1 expression may play a significant role in the pathophysiology of POP. The finding that BMP1 expression was correlated with COL1 expression in all groups suggests a conserved association between BMP1 and collagen synthesis in the vaginal wall. The elevated slope between COL1 and COL3 expressions may be associated with early (premenopausal) development of POP. The expression of RXFP1 in postmenopausal women and its altered intergene regulation suggests a role for RXFP1 in connective tissue metabolism outside pregnancy.

Project description:BACKGROUND:Connective tissue growth factor (CCN2; CTGF) is a newly identified growth factor, which is involved in the regulation of wound repair and fibrosis. Because there is variation among individuals with respect to tissue response to injury, genetic factors might be involved in the final outcome of tissue repair or scarring. For example, polymorphisms in the promoter region of genes, such as those encoding transforming growth factor beta1 (TGF-beta1), interleukin 10 (IL-10), and tumour necrosis factor alpha (TNF-alpha), influence transcriptional responses and are thought to contribute to the dysregulation of these genes in pathological conditions. AIM:To investigate whether the promoter region of the ccn2 (ctgf) gene contains polymorphic sequences that might account for differential expression. MATERIALS/METHODS:Seventy seven human DNA samples were sequenced-45 were from healthy controls and 32 were from patients with ischaemic heart disease (IHD)-using M13 tailed sequence specific ccn2 (ctgf) primers for amplification of a 600 bp fragment upstream of the transcription start site. Amplicons were bidirectionally sequenced with a dye primer M13 forward and reverse sequencing kit. RESULTS:A C to G substitution was identified at position -132 in one of the patients with IHD. Moreover, in five of the 32 patients with IHD and in six of the 45 healthy controls, a G to C polymorphism was found at position -447. These substitutions at -132 and -447 are thought to lie within predicted binding domains for the transcription factors Pbx-1 and MZF1, respectively. In addition, insertions at position -43 (G), -47 (C), -71 (G) and a C to T substitution at position -198 were found in all DNA samples compared with the published ccn2 (ctgf) promoter sequence. These corrections do not involve sequences predicted to function as transcription factor binding sites. CONCLUSION:Sequence analysis of the ccn2 (ctgf) promoter of 77 human DNA samples has revealed corrections and polymorphic sites. The latter lie within putative regulatory elements.

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Proteoglycan metabolism in the connective tissue of pregnant and non-pregnant human cervix. An in vitro study.

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