Dual effect of nifedipine on pregnant human myometrium contractility: Implication of TRPC1.
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ABSTRACT:
SUBMITTER: Yart L
PROVIDER: S-EPMC9306527 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundHuman 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 findingsHuman myometrium biopsies were obtained from pregnant women undergoing cesarean section at term. Immunohistochemistry analysis showed that cystathionine-γ-lyase (CSE) and cystathionine-β-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/significanceH(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:During gestation, uterine smooth muscle cells transition from a state of quiescence to one of contractility, but the molecular mechanisms underlying this transition at a genomic level are not well-known. To better understand these events, we evaluated the epigenetic landscape of the mouse myometrium during the pregnant, laboring, and postpartum stages. We generated gestational time point-specific enrichment profiles for histone H3 acetylation on lysine residue 27 (H3K27ac), histone H3 trimethylation of lysine residue 4 (H3K4me3), and RNA polymerase II (RNAPII) occupancy by chromatin immunoprecipitation with massively parallel sequencing (ChIP-seq), as well as gene expression profiles by total RNA-sequencing (RNA-seq). Our findings reveal that 533 genes, including known contractility-driving genes (Gap junction alpha 1 [Gja1], FBJ osteosarcoma oncogene [Fos], Fos-like antigen 2 [Fosl2], Oxytocin receptor [Oxtr], and Prostaglandin G/H synthase 2 (Ptgs2), for example), are up-regulated at day 19 during active labor because of an increase in transcription at gene bodies. Labor-associated promoters and putative intergenic enhancers, however, are epigenetically activated as early as day 15, by which point the majority of genome-wide H3K27ac or H3K4me3 peaks present in term laboring tissue is already established. Despite this early exhibited histone signature, increased noncoding enhancer RNA (eRNA) production at putative intergenic enhancers and recruitment of RNAPII to the gene bodies of labor-associated loci were detected only during labor. Our findings indicate that epigenetic activation of the myometrial genome precedes active labor by at least 4 days in the mouse model, suggesting that the myometrium is poised for rapid activation of contraction-associated genes in order to exit the state of quiescence.
| S-EPMC7384763 | biostudies-literature
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:Metabolic inactivation of progesterone within uterine myocytes by 20α-hydroxysteroid dehydrogenase (20α-HSD) has been postulated as a mechanism contributing to functional progesterone withdrawal at term. In humans, 20α-HSD is encoded by the gene AKR1C1. Myometrial AKR1C1 mRNA abundance has been reported to increase significantly during labor at term. In spontaneous preterm labor, however, we previously found no increase in AKR1C1 mRNA level in the myometrium except for preterm labor associated with clinical chorioamnionitis. This suggests that increased 20α-HSD activity is a mechanism through which inflammation drives progesterone withdrawal in preterm labor. In this study, we have determined the effects of various treatments of therapeutic relevance on AKR1C1 expression in pregnant human myometrium in an ex vivo culture system. AKR1C1 expression increased spontaneously during 48 h culture (p < 0.0001), consistent with the myometrium transitioning to a labor-like phenotype ex vivo, as reported previously. Serum supplementation, prostaglandin F2α, phorbol myristate acetate, and mechanical stretch had no effect on the culture-induced increase, whereas progesterone (p = 0.0058) and cAMP (p = 0.0202) further upregulated AKR1C1 expression. In contrast, culture-induced upregulation of AKR1C1 expression was dose-dependently repressed by three histone/protein deacetylase inhibitors: trichostatin A at 5 (p = 0.0172) and 25 µM (p = 0.0115); suberoylanilide hydroxamic acid at 0.5 (p = 0.0070), 1 (p = 0.0045), 2.5 (p = 0.0181), 5 (p = 0.0066) and 25 µM (p = 0.0014); and suberoyl bis-hydroxamic acid at 5 (p = 0.0480) and 25 µM (p = 0.0238). We propose the inhibition of histone/protein deacetylation helps to maintain the anti-inflammatory, pro-quiescence signaling of progesterone in pregnant human myometrium by blocking its metabolic inactivation. Histone deacetylase inhibitors may represent a class of agents that preserve or restore the progesterone sensitivity of the pregnant uterus.
| S-EPMC10784398 | 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