Dual effect of nifedipine on pregnant human myometrium contractility: Implication of TRPC1.
Ontology highlight
ABSTRACT:
SUBMITTER: Yart L
PROVIDER: S-EPMC9306527 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:BACKGROUND: Human uterus undergoes distinct molecular and functional changes during pregnancy and parturition. Hydrogen sulfide (H(2)S) has recently been shown to play a key role in the control of smooth muscle tension. The role of endogenous H(2)S produced locally in the control of uterine contractility during labour is unknown. METHODOLOGY/PRINCIPAL FINDINGS: Human myometrium biopsies were obtained from pregnant women undergoing cesarean section at term. Immunohistochemistry analysis showed that cystathionine-?-lyase (CSE) and cystathionine-?-synthetase (CBS), the principle enzymes responsible for H(2)S generation, were mainly localized to smooth muscle cells of human pregnant myometrium. The mRNA and protein expression of CBS as well as H(2)S production rate were down-regulated in labouring tissues compared to nonlabouring tissues. Cumulative administration of L-cysteine (10(-7)-10(-2) mol/L), a precursor of H(2)S, caused a dose-dependent decrease in the amplitude of spontaneous contractions in nonlabouring and labouring myometrium strips. L-cysteine at high concentration (10(-3) mol/L) increased the frequency of spontaneous contractions and induced tonic contraction. These effects of L-cysteine were blocked by the inhibitors of CBS and CSE. Pre-treatment of myometrium strips with glibenclamide, an inhibitor of ATP-sensitive potassium (K(ATP)) channels, abolished the inhibitory effect of L-cysteine on spontaneous contraction amplitude. The effects of L-cysteine on the amplitude of spontaneous contractions and baseline muscle tone were less potent in labouring tissues than that in nonlabouring strips. CONCLUSION/SIGNIFICANCE: H(2)S generated by CSE and CBS locally exerts dual effects on the contractility of pregnant myometrium. Expression of H(2)S synthetic enzymes is down-regulated during labour, suggesting that H(2)S is one of the factors involved in the transition of pregnant uterus from quiescence to contractile state after onset of parturition.
| S-EPMC3160323 | biostudies-literature
Project description:Context: Increased uterine stretch appears to increase the risk of preterm labour, but the mechanism is unknown. Objectives: To identify a targetable mechanism mediating the effect of stretch on human myometrium. Design: Myometrial explants, prepared from biopsies obtained at elective caesarean delivery, were either studied acutely, or were maintained in prolonged culture (up to 65 h) under tension with either a 0.6 g or 2.4 g mass, and compared using in vitro contractility, whole genome array, and qRT-PCR. Results: Increased stretch for 24 or 65 h increased potassium-induced and oxytocin-induced contractility. Gene array identified 62 differentially expressed transcripts after 65 h exposure to increased stretch. Two probes for gastrin-releasing peptide (GRP), a known stimulatory agonist of smooth muscle, were among the top five up-regulated by stretch (3.4-fold and 2.0-fold). Up-regulation of GRP by stretch was confirmed in a separate series of 10 samples using qRT-PCR (2.8-fold, P = 0.01). GRP stimulated contractions acutely when added to freshly obtained myometrial strips in 3 out of 9 cases, but Western blot demonstrated expression of the GRP receptor in 9 out of 9 cases. Prolonged incubation of stretched explants in the GRP antagonists PD-176252 or RC-3095 (65 and 24 h respectively) significantly reduced potassium chloride and oxytocin-induced contractility. Conclusion: Stretch of human myometrium increases contractility and stimulates the expression of a known smooth muscle stimulatory agonist, GRP. Incubation of myometrium in GRP receptor antagonists ameliorates the effect of stretch. GRP may be a target for novel therapies to reduce the risk of preterm birth in multiple pregnancy.
2012-06-15 | GSE31329 | GEO
Project description:Context: Progesterone is important physiologically and therapeutically to maintain uterine quiescence during pregnancy. It acts in part through controlling myometrial gene expression. Objective: To use expression microarray and qRT-PCR validation to determine the changes in gene expression induced by prolonged exposure to a synthetic progestogen. Design: Myometrial explants, obtained at elective Caesarean section (n=9 patients), were maintained in culture, under 0.6g tension, for 3 days in the presence or absence of medroxyprogesterone acetate (MPA, 100nM). Expression array was performed using Illumina human-8 v3 beadchip arrays. Approximately 30% of differentially expressed transcripts were validated in biological replicates (n=10) using qRT-PCR. Results: Transcripts from 114 genes were significantly differentially expressed. These were significantly enriched in inflammatory response (P=0.00001), growth factor activity (P=0.0004) and cytokine activity genes (P=0.008). 34 transcripts were validated using qRT-PCR using an additional independent sample set obtained from 10 further women. There was very close agreement in the fold changes obtained by array and qRT-PCR analysis (r2=0.9, P<0.0001). We confirmed significant down-regulation of a number of genes which have been well characterized as progesterone sensitive, such as IL1B, IL6, PTGS2 and GJA1. However, the top and 6th most down-regulated genes encoded two cytokines, IL11 and IL24, respectively, not previously implicated in mediating the effects of progesterone in myometrium. Both were validated by qRT-PCR (4.3-fold and 2.2-fold down-regulated, both P<0.001). Conclusions: Progestogens control expression of multiple genes in myometrium, including many with no previously recognised role, including IL11 and IL24. It is plausible that proteins encoded by some of these genes may have important, but as yet uncharacterized effects in controlling human parturition.
2011-06-08 | GSE22961 | GEO
Project description:Context: Progesterone is important physiologically and therapeutically to maintain uterine quiescence during pregnancy. It acts in part through controlling myometrial gene expression. Objective: To use expression microarray and qRT-PCR validation to determine the changes in gene expression induced by prolonged exposure to a synthetic progestogen. Design: Myometrial explants, obtained at elective Caesarean section (n=9 patients), were maintained in culture, under 0.6g tension, for 3 days in the presence or absence of medroxyprogesterone acetate (MPA, 100nM). Expression array was performed using Illumina human-8 v3 beadchip arrays. Approximately 30% of differentially expressed transcripts were validated in biological replicates (n=10) using qRT-PCR. Results: Transcripts from 114 genes were significantly differentially expressed. These were significantly enriched in inflammatory response (P=0.00001), growth factor activity (P=0.0004) and cytokine activity genes (P=0.008). 34 transcripts were validated using qRT-PCR using an additional independent sample set obtained from 10 further women. There was very close agreement in the fold changes obtained by array and qRT-PCR analysis (r2=0.9, P<0.0001). We confirmed significant down-regulation of a number of genes which have been well characterized as progesterone sensitive, such as IL1B, IL6, PTGS2 and GJA1. However, the top and 6th most down-regulated genes encoded two cytokines, IL11 and IL24, respectively, not previously implicated in mediating the effects of progesterone in myometrium. Both were validated by qRT-PCR (4.3-fold and 2.2-fold down-regulated, both P<0.001). Conclusions: Progestogens control expression of multiple genes in myometrium, including many with no previously recognised role, including IL11 and IL24. It is plausible that proteins encoded by some of these genes may have important, but as yet uncharacterized effects in controlling human parturition. 9 paired samples of human myometrium treated with MPA (10-7M) or vehicle
2011-06-08 | E-GEOD-22961 | biostudies-arrayexpress
Project description:Context: Increased uterine stretch appears to increase the risk of preterm labour, but the mechanism is unknown. Objectives: To identify a targetable mechanism mediating the effect of stretch on human myometrium. Design: Myometrial explants, prepared from biopsies obtained at elective caesarean delivery, were either studied acutely, or were maintained in prolonged culture (up to 65 h) under tension with either a 0.6 g or 2.4 g mass, and compared using in vitro contractility, whole genome array, and qRT-PCR. Results: Increased stretch for 24 or 65 h increased potassium-induced and oxytocin-induced contractility. Gene array identified 62 differentially expressed transcripts after 65 h exposure to increased stretch. Two probes for gastrin-releasing peptide (GRP), a known stimulatory agonist of smooth muscle, were among the top five up-regulated by stretch (3.4-fold and 2.0-fold). Up-regulation of GRP by stretch was confirmed in a separate series of 10 samples using qRT-PCR (2.8-fold, P = 0.01). GRP stimulated contractions acutely when added to freshly obtained myometrial strips in 3 out of 9 cases, but Western blot demonstrated expression of the GRP receptor in 9 out of 9 cases. Prolonged incubation of stretched explants in the GRP antagonists PD-176252 or RC-3095 (65 and 24 h respectively) significantly reduced potassium chloride and oxytocin-induced contractility. Conclusion: Stretch of human myometrium increases contractility and stimulates the expression of a known smooth muscle stimulatory agonist, GRP. Incubation of myometrium in GRP receptor antagonists ameliorates the effect of stretch. GRP may be a target for novel therapies to reduce the risk of preterm birth in multiple pregnancy. 9 paired samples of human myometrium cultured under low (0.6g) or high (2.4g) tension
2012-06-14 | E-GEOD-31329 | biostudies-arrayexpress
Project description:The mechanisms governing maintenance of quiescence during pregnancy remain largely unknown. The current study characterizes a stretch-activated, tetraethylammonium-insensitive K(+) current in smooth muscle cells isolated from pregnant human myometrium. This study hypothesizes that these K(+) currents can be attributed to TREK-1 and that upregulation of this channel during pregnancy assists with the maintenance of a negative cell membrane potential, conceivably contributing to uterine quiescence until full term. The results of this study demonstrate that, in pregnant human myometrial cells, outward currents at 80 mV increased from 4.8 ± 1.5 to 19.4 ± 7.5 pA/pF and from 3.0 ± 0.8 to 11.8 ± 2.7 pA/pF with application of arachidonic acid (AA) and NaHCO3, respectively, causing intracellular acidification. Similarly, outward currents were inhibited following application of 10 μM fluphenazine by 51.2 ± 9.8% after activation by AA and by 73.9 ± 4.2% after activation by NaHCO3. In human embryonic kidney (HEK-293) cells stably expressing TREK-1, outward currents at 80 mV increased from 91.0 ± 23.8 to 247.5 ± 73.3 pA/pF and from 34.8 ± 8.9 to 218.6 ± 45.0 pA/pF with application of AA and NaHCO3, respectively. Correspondingly, outward currents were inhibited 89.5 ± 2.3% by 10 μM fluphenazine following activation by AA and by 91.6 ± 3.4% following activation by NaHCO3. Moreover, currents in human myometrial cells were activated by stretch and were reduced by transfection with small interfering RNA or extracellular acidification. Understanding gestational regulation of expression and gating of TREK-1 channels could be important in determining appropriate maintenance of uterine quiescence during pregnancy.
| S-EPMC3761174 | biostudies-literature
Project description:We describe here the expression of the ryanodine receptor isoforms RyR2 and RyR3 in human non-pregnant and pregnant (non-labouring) myometrium, and in isolated cultured myometrial cells. The mRNA encoding the RyR3 isoform was found in both non-pregnant and pregnant myometrial tissue samples; however, the mRNA for RyR2 was found only in pregnant samples. It can be speculated that the appearance of this additional isoform in the pregnant myometrium may increase the ability of this tissue to contract at term. Control of expression of the RyR2 gene may therefore be another example of an up-regulated signalling system in pregnancy. Although the mRNA for RyR3 was expressed in cultured myometrial cells, the mRNA for RyR2 could not be detected. Thus cultured myometrial cells appear to be similar to the non-pregnant myometrium. The cytokine transforming growth factor beta (TGF-beta) has been reported to alter RyR mRNA expression in many cell types. After treatment with TGF-beta, both RyR2 and RyR3 mRNAs could be detected in cultured myometrial cells. These observations support the idea that the expression of the RyR2 isoform is up-regulated both in pregnancy and in TGF-beta-treated cultured myometrial cells. Using measurements of 45Ca2+ release, we have further demonstrated that cultured human myometrial cells show a significant augmentation of both the Ca2+-induced Ca2+ release (CICR) mechanism and ryanodine-induced Ca2+ release after treatment with TGF-beta. Additionally, caffeine was able to induce Ca2+ release and sensitize the CICR mechanism to ryanodine. Thus we suggest that the appearance of RyR2 mRNA leads to the expression of this receptor/channel protein with identifiable pharmacological characteristics. These results are discussed in the context of the potential role of gene activation in the process of maturation of the human myometrium during pregnancy.
| S-EPMC1218255 | biostudies-other
Project description:Matrix metalloproteinases 2 and 9 (MMP2/9) have previously been shown to be elevated in serum and amniotic fluid from women undergoing preterm birth. We performed experiments to determine the effects of MMP2/9 on uterine contraction and birth timing. Pregnant mice were injected daily with 50 mg/kg of SB-3CT or vehicle control beginning on gestational day 14-18 to determine if MMP2/9 inhibition would affect parturition timing. MMP2/9 expression in human myometrial tissue was determined by Simple Western (Wes) and semiquantitative western blot. Purified MMP2/9 and SB-3CT inhibitor were added to human myometrial strips to determine the effects of MMP2/9 on oxytocin-induced uterine contraction. Parturition was delayed in mice treated with MMP2/9 inhibitor SB-3CT. MMP2/9 protein levels were elevated in preterm laboring uterine myometrium. Gelatinase activity was confirmed in cell extracts and supernatants from immortalized and primary human uterine myometrial cells in culture. Addition of purified MMP2/9 increased the oxytocin-induced contractile response in myometrial tissue strips from pregnant women. In contrast, addition of the MMP2/9 inhibitor SB-3CT decreased the contractile response to oxytocin in a dose-dependent manner. These results suggest abnormal MMP2/9 expression affects the contractile state of the uterine myometrium to promote parturition and that MMP2/9 inhibition attenuates this effect.
| S-EPMC6561860 | biostudies-literature
Project description:BACKGROUND:Oxytocin receptor (OXTR) gene variants have been shown to affect the prevalence of preterm birth, mode of delivery and oxytocin (OXT) requirements for labor induction and augmentation. We hypothesized that this might be associated with different myometrium responses to oxytocin. Our aim was to investigate the influence of a selection of eight OXTR gene single nucleotide variants on oxytocin-induced stimulation of human myometrium contractility in vitro. METHODS:Human myometrium biopsies were collected during elective cesarean sections at term, if patients had given informed consent. Myometrial strips were submerged under tension in an organ bath and allowed to contract; the remaining material was stored at -?80?°C for further determination of relevant genetics and mRNA level. The area under the curve (AUC) of all contractions taking place in the absence of OXT and of those occurring upon OXT addition (for 30?min each) was measured. OXT stimulation, defined as the ratio between AUC measurements after OXT addition and those in the absence of OXT was calculated for each strip. TaqMan™ Assays were used to detect the allele distribution of the eight OXTR variants and to determine the relative amounts of OXTR-mRNA in the samples. For each variant, oxytocin stimulation of contractility was compared between samples homozygous for the reference allele (reference group) and samples with at least one variant allele (variant group) by linear regression. RESULTS:Sixty samples were included in the present study. For rs1042778, rs11706648, rs4686301, rs53576, rs237895, and rs237902, OXT stimulation was similar in the reference and in the variant groups. However, the values of OXT stimulation differed significantly between the reference and the variant groups for rs4686302 (3.1 vs. 4.1 times; p =?0.022) and rs237888 (3.2 vs. 5.5 times; p =?0.001). No significant differences between the levels of OXTR-mRNA in the various reference and corresponding variant groups were detected. CONCLUSIONS:Patients with variant alleles of rs237888 and/or rs4686302 may be more sensitive to oxytocin stimulation, explaining why these sequence variants have been associated with lower cesarean section prevalence and premature birth, respectively.
| S-EPMC6852767 | biostudies-literature
Project description:Focal adhesions are integrin-rich microdomains that structurally link the cytoskeleton to the extracellular matrix and transmit mechanical signals. In the pregnant uterus, increases in integrin expression and activation are thought to be critical for the formation of the mechanical syncytium required for labor. The aim of this study was to determine which integrins are upregulated and localized to focal adhesions in pregnant human myometrium. We used quantitative polymerase chain reaction, Western blotting, and confocal microscopy to determine the expression levels and colocalization with focal adhesion proteins. We observed increases in several integrin transcripts in pregnant myometrium. At the protein level, integrins such as ?5-integrin (ITGA5), ITGA7, ITGAV, and ITGB3 were significantly increased during pregnancy. The integrins ITGA3, ITGA5, ITGA7, and ITGB1 colocalized with focal adhesion proteins in term human myometrium. These data suggest that integrins ?3?1, ?5?1, and ?7?1 are the most likely candidates to transmit mechanical signals from the extracellular matrix through focal adhesions in pregnant human myometrium.
| S-EPMC3678871 | biostudies-other