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Lai PF, Young RC, Tribe RM, et al., 2021, Evaluating aminophylline and progesterone combination treatment to modulate contractility and labor‐related proteins in pregnant human myometrial tissues, Pharmacology Research & Perspectives, Vol: 9, Pages: 1-18, ISSN: 2052-1707
Progesterone (P4) and cyclic adenosine monophosphate (cAMP) are regarded as pro-quiescent factors that suppress uterine contractions during pregnancy. We previously used human primary cells in vitro and mice in vivo to demonstrate that simultaneously enhancing myometrial P4 and cAMP levels may reduce inflammation-associated preterm labor. Here, we assessed whether aminophylline (Ami; phosphodiesterase inhibitor) and P4 can reduce myometrial contractility and contraction-associated proteins (CAPs) better together than individually; both agents are clinically used drugs. Myometrial tissues from pregnant non-laboring women were treated ex vivo with Ami acutely (while spontaneous contracting) or throughout 24-h tissue culture (±P4); isometric tension measurements, PKA assays, and Western blotting were used to assess tissue contractility, cAMP action, and inflammation. Acute (1 h) treatment with 250 and 750 μM Ami reduced contractions by 50% and 84%, respectively, which was not associated with a directly proportional increase in whole tissue PKA activity. Sustained myometrial relaxation was observed during 24-h tissue culture with 750 μM Ami, which did not require P4 nor reduce CAPs. COX-2 protein can be reduced by 300 nM P4 but this did not equate to myometrial relaxation. Ami (250 μM) and P4 (100 and 300 nM) co-treatment did not prevent oxytocin-augmented contractions nor reduce CAPs during interleukin-1β stimulation. Overall, Ami and P4 co-treatment did not suppress myometrial contractions more than either agent alone, which may be attributed to low specificity and efficacy of Ami; cAMP and P4 action at in utero neighboring reproductive tissues during pregnancy should also be considered.
Li JKH, Lai PF, Tribe RM, et al., 2021, Transcription factors regulated by cAMP in smooth muscle of the myometrium at human parturition., Biochemical Society Transactions, Vol: 49, Pages: 997-1011, ISSN: 0300-5127
Cyclic adenosine monophosphate (cAMP) contributes to maintenance of a quiescent (relaxed) state in the myometrium (i.e. uterine smooth muscle) during pregnancy, which most commonly has been attributed to activation of protein kinase A (PKA). PKA-mediated phosphorylation of cytosolic contractile apparatus components in myometrial smooth muscle cells (mSMCs) are known to promote relaxation. Additionally, PKA also regulates nuclear transcription factor (TF) activity to control expression of genes important to the labour process; these are mostly involved in actin-myosin interactions, cell-to-cell connectivity and inflammation, all of which influence mSMC transition from a quiescent to a contractile (pro-labour) phenotype. This review focuses on the evidence that cAMP modulates the activity of TFs linked to pro-labour gene expression, predominantly cAMP response element (CRE) binding TFs, nuclear factor κB (NF-κB), activator protein 1 (AP-1) family and progesterone receptors (PRs). This review also considers the more recently described exchange protein directly activated by cAMP (EPAC) that may oppose the pro-quiescent effects of PKA, as well as explores findings from other cell types that have the potential to be of novel relevance to cAMP action on TF function in the myometrium.
Lai PF, Georgiou EX, Tribe RM, et al., 2020, The impact of progesterone and RU-486 on classic pro-labour proteins & contractility in human myometrial tissues during 24-hour exposure to tension & Interleukin-1β, Molecular and Cellular Endocrinology, Vol: 500, ISSN: 0303-7207
Increased expression of pro-labour genes that encode cyclooxygenase-2 (COX-2), oxytocin receptor (OTR) and connexin-43 (Cx43) at parturition is often attributed to P4 functional withdrawal, based on findings from animal models and human primary myometrial cells. However, the cause of reduced myometrial P4 responsiveness that promotes contractions at labour is not fully determined. Uterine stretch occurs with advancing gestation but most in vitro experimental models do not take this into consideration. We aimed to examine whether tissue-level myometrial stretch influences the ability of P4 to regulate pro-labour protein abundance by using myometrial biopsies from term gestation pregnant women to assess the impact of 24 h exposure to combinations of (i) stretch-mediated tension, (ii) P4 (100 nM) and (iii) an anti-progestin, RU-486 (1 μM). Firstly, we observed baseline COX-2 and Cx43 protein levels increased, whereas P4 content along with calponin-1 and progesterone receptor (PR) protein abundance decreased, in vehicle-treated tissues. P4 supplementation subtly reduced COX-2 levels in un-stretched tissues. Spontaneous and oxytocin-augmented contractility were unchanged by tissue culture exposure to P4 and/or RU-486. Interleukin-1β (IL-1β; 1 ng/ml) enhanced COX-2 protein and PGE2 content in un-stretched tissues. Overall, tissue stretch may, in part, regulate P4-sensitive pro-labour protein levels, but this is likely to be reliant on interaction with other in utero factors that were absent in our tissue cultures. More complex culture conditions should be evaluated in future to aid further development of a physiologically relevant model to improve our understanding of in utero myometrial P4 responsiveness.
Herbert BR, Markovic D, Georgiou E, et al., 2019, Aminophylline and progesterone prevent inflammation-induced preterm parturition in the mouse, Biology of Reproduction, Vol: 101, Pages: 813-822, ISSN: 1529-7268
Although progesterone (P4) supplementation is the most widely used therapy for the prevention of preterm labor (PTL), reports of its clinical efficacy have been conflicting. We have previously shown that the anti-inflammatory effects of P4 can be enhanced by increasing intracellular cAMP levels in primary human myometrial cells. Here we have examined whether adding aminophylline (Am), a non-specific phosphodiesterase (PDE) inhibitor that increases intracellular cyclic adenosine monophosphate (cAMP) levels, to P4 might improve its efficacy using in vivo and in vitro models of PTL. In a mouse model of lipopolysaccharide (LPS)-induced PTL, we found that the combination of P4 and Am delayed the onset of LPS-induced PTL, while the same dose of P4 and Am alone had no effect. Pup survival was not improved by either agent alone or in combination. Myometrial prolabor and inflammatory cytokine gene expression was reduced, but the reduction was similar in P4 and P4/Am treated mice. There was no effect of the combination of P4 and Am on an ex vivo assessment of myometrial contractility. In human myometrial cells and myometrial tissue explants, we found that the combination had marked anti-inflammatory effects, reducing cytokine and COX-2 mRNA and protein levels to a greater extent than either agent alone. These data suggest that the combination of P4 and Am has a more potent anti-inflammatory effect than either agent alone and may be an effective combination in women at high-risk of PTL.
Stanfield Z, Lai PF, Lei K, et al., 2019, Corrigendum: Myometrial transcriptional signatures of human parturition, Frontiers in Genetics, Vol: 10, ISSN: 1664-8021
A Corrigendum onMyometrial Transcriptional Signatures of Human Parturitionby Stanfield, Z., Lai, P. F., Lei, K., Johnson, M. R., Blanks, A. M., Romero, R., et al. (2019). Front. Genet. 10:185. doi: 10.3389/fgene.2019.00185“Pei F. Lai” and “Kaiyu Lei” were not included as authors in the published article. Due to the addition of authors, the list of affiliations had been updated accordingly. The corrected Author Contributions Statement appears below.
Stanfield Z, Johnson MR, Blanks AM, et al., 2019, Myometrial transcriptional signatures of human parturition, Frontiers in Genetics, Vol: 10, ISSN: 1664-8021
The process of parturition involves the transformation of the quiescent myometrium (uterine smooth muscle) to the highly contractile laboring state. This is thought to be driven by changes in gene expression in myometrial cells. Despite the existence of multiple myometrial gene expression studies, the transcriptional programs that initiate labor are not known. Here, we integrated three transcriptome datasets, one novel (NCBI Gene Expression Ominibus: GSE80172) and two existing, to characterize the gene expression changes in myometrium associated with the onset of labor at term. Computational analyses including classification, singular value decomposition, pathway enrichment, and network inference were applied to individual and combined datasets. Outcomes across studies were integrated with multiple protein and pathway databases to build a myometrial parturition signaling network. A high-confidence (significant across all studies) set of 126 labor genes were identified and machine learning models exhibited high reproducibility between studies. Labor signatures included both known (interleukins, cytokines) and unknown (apoptosis, MYC, cell proliferation/differentiation) pathways while cyclic AMP signaling and muscle relaxation were associated with non-labor. These signatures accurately classified and characterized the stages of labor. The data-derived parturition signaling networks provide new genes/signaling interactions to understand phenotype-specific processes and aid in future studies of parturition.
Shah NM, Lai PF, Imami N, et al., 2019, Progesterone-related immune modulation of pregnancy and labor, Frontiers in Endocrinology, Vol: 10, ISSN: 1664-2392
Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.
Lai PF, Young RC, Tribe RM, et al., 2018, The Efficacy of Aminophylline and Progesterone Co-Treatment to Suppress Human Myometrial Contractions during Prolonged Exposure., 65th Annual Scientific Meeting of the Society-for-Reproductive-Investigation (SRI), Publisher: SAGE PUBLICATIONS INC, Pages: 104A-104A, ISSN: 1933-7191
Lai PF, Tribe RM, Johnson MR, 2017, Effects of Tension on cAMP-Driven Control of Contractility in Human Myometrial Tissue., 64th Annual Scientific Meeting of the Society-for-Reproductive-Investigation (SRI), Publisher: SAGE PUBLICATIONS INC, Pages: 244A-244A, ISSN: 1933-7191
Georgiou E, Lei K, Lai P, et al., 2016, Progesterone repression of IL-1 beta action is maintained in human myometrium after the onset of labour, Publisher: WILEY-BLACKWELL, Pages: E12-E13, ISSN: 1470-0328
Lai PF, Tribe RM, Johnson MR, 2016, Differential impact of acute and prolonged cAMP agonist exposure on protein kinase A activation and human myometrium contractile activity, Journal of Physiology-London, Vol: 594, Pages: 6369-6393, ISSN: 1469-7793
Acute cAMP elevation inhibits myometrial contractility, but the mechanisms responsible are not fully defined and the long-term effects uncertain. These need to be defined in pregnant human myometrium before the therapeutic potential of cAMP-elevating agents in the prevention of preterm labour can be realised. In the present study, we tested the hypotheses that PKA activity is necessary for cAMP-induced myometrial relaxation and prolonged cAMP elevation can prevent myometrial contractions. Myometrial tissues obtained from term, pre-labour elective Caesarean sections were exposed to receptor-independent cAMP agonists to determine the relationship between myometrial contractility (spontaneous and oxytocin-induced), PKA activity, HSP20 phosphorylation and expression of contraction-associated and cAMP signalling proteins. Acute (1 h) application of cAMP agonists promoted myometrial relaxation but this was weakly related to PKA activation. PKA-specific activator, 6-Bnz-cAMP, increased PKA activity (6.8 ± 2.0 mean fold versus vehicle; P = 0.0313) without inducing myometrial relaxation. Spontaneous myometrial contractility declined after 24 h but was less marked when tissues were constantly exposed to cAMP agonists, especially for 8-bromo-cAMP (4.3 ± 1.2 mean fold versus vehicle; P = 0.0043); this was associated with changes to calponin, cofilin and HSP20 phosphorylated/total protein levels. Oxytocin-induced contractions were unaffected by pre-incubation with cAMP agonists despite treatments being able to enhance PKA activity and HSP20 phosphorylation. These data suggest that cAMP-induced myometrial relaxation is not solely dependent on PKA activity and the ability of cAMP agonists to repress myometrial contractility is lost with prolonged exposure. We conclude that cAMP agonist treatment alone may not prevent preterm labour.
Georgiou EX, Lei K, Lai PF, et al., 2016, The study of progesterone action in human myometrial explants., Molecular Human Reproduction, ISSN: 1460-2407
STUDY HYPOTHESIS: Myometrial explants represent a superior model compared with cell culture models for the study of human myometrial progesterone (P4) signalling in parturition. STUDY FINDING: Gene expression analysis showed myometrial explants closely resemble the in vivo condition and the anti-inflammatory action of P4 is not lost with labour onset. WHAT IS KNOWN ALREADY: Circulating P4 levels decline before the onset of parturition in most animals, but not in humans. This has led to the suggestion that there is a functional withdrawal of P4 action at the myometrial level prior to labour onset. However, to date, no evidence of a loss of P4 function has been provided, with studies hampered by a lack of a physiologically relevant model. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: Myometrial biopsies obtained at Caesarean section were dissected into explants after a portion was immediately snap frozen (t = 0). Microarray analysis was used to compare gene expression of t = 0 with paired (i) explants, (ii) passage 4 myometrial cell cultures or (iii) the hTERT myometrial cell line. Western blotting and chemokine/cytokine assays were used to study P4 signalling in myometrial explants. MAIN RESULTS AND THE ROLE OF CHANCE: Gene expression comparison of t = 0 to the three models demonstrated that explants more closely resemble the in vivo status. At the protein level, explants maintain both P4 receptor (PR) and glucocorticoid receptor (GR) levels versus t = 0 whereas cells only maintain GR levels. Additionally, treatment with 1 µM P4 led to a reduction in interleukin-1 (IL-1) β-driven cyclooxygenase-2 in explants but not in cells. P4 signalling in explants was PR-mediated and associated with a repression of p65 and c-Jun phosphorylation. Furthermore, the anti-inflammatory action of P4 was maintained after labour onset. LIMITATIONS/REASONS FOR CAUTION: There is evidence of basal inflammation in the myometrial explant model. WIDER IMPLICATIONS OF THE FINDINGS: Myomet
Georgiou EX, Lai PF, Yulia A, et al., 2015, Progesterone Repression of IL-1 beta-Driven COX-2 Expression in Myometrial Explant Cultures, Publisher: SAGE PUBLICATIONS INC, Pages: 134A-134A, ISSN: 1933-7191
Lai PF, Tribe RM, Johnson MR, 2015, Sustained Presence of Progesterone Reduces Spontaneous Contractility Enhanced By Prolonged Exposure To 8-bromo-cAMP., Publisher: SAGE PUBLICATIONS INC, Pages: 334A-334A, ISSN: 1933-7191
Newton GK, Perrior TR, Jenkins K, et al., 2014, The Discovery of Potent, Selective, and Reversible Inhibitors of the House Dust Mite Peptidase Allergen Der p 1: An Innovative Approach to the Treatment of Allergic Asthma, JOURNAL OF MEDICINAL CHEMISTRY, Vol: 57, Pages: 9447-9462, ISSN: 0022-2623
Lai PF, Tribe RM, Johnson MR, 2014, Prolonged Exposure to cAMP Enhancers Increases Pregnant Human Myometrium Contractility and Alters Contraction-Associated Protein Expression, 61st Annual Scientific Meeting of the Society-for-Gynecologic-Investigation (SGI), Publisher: SAGE PUBLICATIONS INC, Pages: 242A-243A, ISSN: 1933-7191
Lai PF, Tribe RM, Johnson MR, 2013, Prolonged Elevation of cAMP Enhances Spontaneous Contractility in Human Myometrium from Pregnant Women at Term, 60th Annual Scientific Meeting of the Society-for-Gynecologic-Investigation (SGI), Publisher: SAGE PUBLICATIONS INC, Pages: 173A-173A, ISSN: 1933-7191
Lai P, Michelangeli F, 2012, Bis(2-hydroxy-3-tert-butyl-5-methyl-phenyl)-methane (bis-phenol) is a potent and selective inhibitor of the secretory pathway Ca2+ ATPase (SPCA1), BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, Vol: 424, Pages: 616-619, ISSN: 0006-291X
Lai P, Yip NC, Michelangeli F, 2011, Regucalcin (RGN/SMP30) alters agonist- and thapsigargin- induced cytosolic [Ca2+] transients in cells by increasing SERCA Ca(2+)ATPase levels, FEBS LETTERS, Vol: 585, Pages: 2291-2294, ISSN: 0014-5793
Lai P, Michelangeli F, 2009, Changes in expression and activity of the secretory pathway Ca2+ ATPase 1 (SPCA1) in A7r5 vascular smooth muscle cells cultured at different glucose concentrations, BIOSCIENCE REPORTS, Vol: 29, Pages: 397-404, ISSN: 0144-8463
Michelangeli F, Ogunbayo OA, Wootton LL, et al., 2008, Endocrine disrupting alkylphenols: Structural requirements for their adverse effects on Ca2+ pumps, Ca2+ homeostasis & Sertoli TM4 cell viability, CHEMICO-BIOLOGICAL INTERACTIONS, Vol: 176, Pages: 220-226, ISSN: 0009-2797
Ogunbayo OA, Lai PF, Connolly TJ, et al., 2008, Tetrabromobisphenol A (TBBPA), induces cell death in TM4 Sertoli cells by modulating Ca2+ transport proteins and causing dysregulation of Ca2+ homeostasis, TOXICOLOGY IN VITRO, Vol: 22, Pages: 943-952, ISSN: 0887-2333
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