Biology subjects

Shynlova, O.

Publications and source records attributed to Shynlova, O..

8 recordsLinked to original sources

bioRxiv2026

Macrophage to Myocyte Mitochondrial Transfer in the Myometrium: A Novel Mechanism for the Initiation of Labor

Labor initiation involves influx of peripheral monocytes into uterine tissue, where they differentiate into macrophages (Macs) and polarize toward pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes. Crosstalk between uterine myocytes (MYO) and Macs is implicated in myometrial activation, but the underlying mechanisms remain unclear. Using immunofluorescence and live-cell imaging, we show that M1-Macs (but not M2-Macs) form tunneling nanotubes (TNT) with MYOs, enabling direct, unidirectional mitochondrial transfer. TNT-mediated mitochondrial transfer enhances ATP production and 20-HSD expression in MYO. Functionally, M1-Macs induce intracellular and functional progesterone (P4) withdrawal in MYOs via 20-HSD mediated P4 metabolism and increased PR-A phosphorylation. In vivo, transfer of monocytes, carrying dendra-labelled mitochondria in pregnant mice confirm their myometrial recruitment, differentiation, polarization to M1-Macs, and M1-Mac/MYO mitochondrial transfer. Increased M1-Macs and mitochondrial transfer to MYOs are observed before labor onset, implicating M1-Macs/MYO interaction as key regulator of labor initiation and potentially a therapeutic target to prevent preterm birth.

immunology↗

bioRxiv2026

A Broad-Spectrum Chemokine Inhibitor Prevents Preterm Labor in Mice by Supressing Inflammation Induced by Intra-Amniotic Injection of Interleukin-1 alpha

Preterm birth (PTB) is a leading cause of perinatal and infant mortality worldwide. PTB can be induced by systemic maternal or intra-uterine infection or by sterile intra-amniotic inflammation driven by alarmins such as interleukin-1 (IL-1). We reported earlier that a Broad-Spectrum Chemokine Inhibitor (BSCI) prevented PTB in murine and non-human primate models of infection-mediated preterm labor. Here, we investigated whether BSCI can prevent PTB in pregnant C57BL/6 mice following ultrasound-guided intra-amniotic injection of IL-1 (400 ng per sac) on gestational day (GD)16.5. Half the mice received BSCI (10 mg/kg, intravenous daily) beginning GD15.5 and through to term. The impact of IL-1 alone or IL-1 plus BSCI was assessed on (i) injection-to-delivery interval, fetal survival, placental and neonatal weight; (ii) cytokine and chemokine levels in maternal plasma and amniotic fluid and inflammatory gene expression in maternal and fetal tissues (Real-Time RT-qPCR); (iii) global transcriptomic profiling of myometrial tissues at 2 and 24 hrs (RNA sequencing) together with examination of myometrial chromatin accessibility (Assay for transposase accessible chromatin sequencing) at 24 hrs; (iv) uterine leukocyte infiltration (immunofluorescence). Pretreatment with BSCI i) prevented IL-1-induced PTB; (ii) significantly attenuated cytokine and chemokine signals in maternal plasma, myometrium, decidua, and placenta, and amniotic fluid; (iii) suppressed myometrial contraction-associated genes, including Nfkb1, Ptgs2, Akr1c18, and Gja1; (iv) prevented global IL-1-induced changes in myometrial gene expression and chromatin accessibility (v) reduced uterine macrophage (F4/80+) counts and prevented the increase in pro-inflammatory M1-like macrophages observed with IL-1-treatment. BSCI-treated dams that delivered at term had live pups with normal placental and fetal weight. Taken together, BSCI reduced the incidence of IL-1-mediated PTB and maintained uterine quiescence by suppressing uterine inflammation and genome-wide changes in labor gene expression and chromatin accessibility. BSCI represents a promising therapeutic approach for PTB prevention in high-risk pregnant women.

physiology↗

bioRxiv2026

Temporal chromatin and transcriptome dynamics driven by JUND and progesterone receptor binding in the pregnant mouse myometrium

The myometrium, the muscle layer of the uterus, undergoes profound phenotypic changes throughout pregnancy, labor, and postpartum, allowing for successful reproduction. Transcriptomic analysis of the murine myometrium revealed distinct gene expression signatures corresponding to these physiological stages, which reflect the dynamic remodeling processes occurring in the uterus during late gestation, term labor, and postpartum. These transcriptomic signatures at specific gestational points were accompanied by changes to the accessible chromatin landscape. Notably, increased chromatin accessibility was observed in the mouse myometrium at full term (gestational day 19) before the onset of active labor contractions. Accessible chromatin regions were bound by the transcription factor JUND, from the AP-1 family, and associated with progesterone receptor (PR) binding. Depletion of the progesterone receptor isoform B (PRB) from accessible chromatin at this prelabor stage implicates progesterone receptor isoform A (PRA) as a binding partner with JUND at prelabor and labor. During labor onset, accessible chromatin regions were associated with elevated production of enhancer RNAs and enriched in binding sites for transcription factors from the AP-1, SOX, and ETS families, implicating additional transcription factors in the labor process. Although PRB was strikingly absent from labor-associated accessible chromatin, it was found associated with histone H3 lysine 27 trimethylated (H3K27me3) repressed regions in late gestation and the postpartum period. These findings provide new insight into the dynamic transcriptional regulatory networks and chromatin-based mechanisms controlling gene expression in the myometrium across gestational stages providing new therapeutic targets for reproductive disorders.

genomics↗

bioRxiv2024

JUND plays a genome-wide role in the quiescent to contractile switch in the pregnant human myometrium

The myometrium, the muscular layer of the uterus, undergoes crucial transitions during pregnancy, maintaining quiescence throughout gestation, and generating coordinated contractions during labor. Dysregulation of this transition can lead to premature labor with serious complications for the infant. Despite extensive gene expression data available for varying myometrial states, the molecular mechanisms governing the increase in contraction- associated gene expression at labor onset remain unclear. Transcription factors, such as JUND and progesterone receptor (PR), play essential roles in regulating transcription of select myometrial contraction-associated genes, however, a broader understanding of their involvement in transcriptional regulation at a genome-wide scale is lacking. This study examines changes in transcription and JUND binding within human myometrial tissue during the transition from quiescence (term-not-in labor/TNIL) to contractility (term labor/TL). Total RNA- sequencing reveals a global increase in primary transcript levels at TL, with AP-1/JUND binding motifs overrepresented in the promoters of upregulated transcripts. Interestingly, ChIP-seq analysis demonstrates higher JUND enrichment in TNIL compared to TL tissues, suggesting its role in preparing the myometrium for labor onset. Integration of JUND and PR ChIP-seq data identifies over 10,000 gene promoters bound by both factors at TNIL and TL, including genes involved in labor-driving processes. Additionally, the study uncovers elevated levels of enhancer RNAs (eRNAs) at intergenic JUND peaks in laboring myometrial tissues, and implicates additional transcription factors, such as NFKB and ETS, in the regulatory switch from quiescence to contractility. In summary, this research enhances our understanding of the myometrial molecular regulatory network during pregnancy and labor, shedding light on the roles of JUND and PR in gene expression regulation genome-wide. These findings open avenues for further exploration, potentially leading to improved interventions for preventing premature labor and the associated complications.

genomics↗

bioRxiv2023

SOX4 exerts contrasting regulatory effects on labor-associated gene promoters in myometrial cells

The uterine muscular layer, or myometrium, undergoes profound changes in global gene expression during its progression from a quiescent state during pregnancy to a contractile state at the onset of labor. In this study, we investigate the role of SOX family transcription factors in myometrial cells and provide evidence for the role of SOX4 in regulating labor-associated genes. We show that Sox4 has elevated expression in the murine myometrium during a term laboring process and in two mouse models of preterm labor. Additionally, SOX4 differentially affects labor-associated gene promoter activity in cooperation with activator protein 1 (AP-1) dimers. SOX4 exerted no effect on the Gja1 promoter; a JUND-specific activation effect at the Fos promoter; a positive activation effect on the Mmp11 promoter with the AP-1 dimers; and surprisingly, we noted that the reporter expression of the Ptgs2 promoter in the presence of JUND and FOSL2 was repressed by the addition of SOX4. Our data indicate SOX4 may play a diverse role in regulating gene expression in the laboring myometrium in cooperation with AP-1 factors. This study enhances our current understanding of the regulatory network that governs the transcriptional changes associated with the onset of labor and highlights a new molecular player that may contribute to the labor transcriptional program.

molecular biology↗

bioRxiv2022

MYB and ELF3 differentially modulate labor-inducing gene expression in myometrial cells

Spontaneous uterine contractions are initiated when smooth muscle cells (SMCs) within the uterine muscle, or myometrium, transition from a functionally dormant to an actively contractile phenotype at the end of the pregnancy period. We know that this process is accompanied by gestational time point-specific differences in the SMC transcriptome, which can be modulated by the Activator protein 1 (AP-1), Nuclear factor kappa beta (Nf-{kappa}{beta}), Estrogen receptor (ER), and Progesterone receptor (PR) transcription factors. Less is known, however, about the additional proteins that might assist these factors in conferring the transcriptional changes observed at labor onset. Here, we present functional evidence for the roles of two proteins previously understudied in the SMC context - MYB and ELF3 - which can contribute to the regulation of labor-driving gene transcription. We show that the MYB and ELF3 genes exhibit elevated transcript expression levels in mouse and human myometrial tissues during spontaneous term labor. The expression of both genes was also significantly increased in mouse myometrium during preterm labor induced by the progesterone antagonist, mifepristone (RU486), but not during infection-simulating preterm labor induced by intrauterine infusion of Lipopolysaccharide (LPS). Furthermore, both MYB and ELF3 proteins affect labor-driving gene promoter activity, although in surprisingly opposing ways: Gja1 and Fos promoter activation increases in the presence of MYB and decreases in the presence of ELF3. Collectively, our study adds to the current understanding of the transcription factor network that defines the transcriptomes of SMCs during late gestation and implicates two new players in the control of labor timing.

molecular biology↗

bioRxiv2020

The pregnant myometrium is epigenetically activated at contractility-driving gene loci prior to the onset of labor in mice

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 pregnancy, labor and post-partum. We established gestational timepoint-specific enrichment profiles involving histone H3K27 acetylation (H3K27ac), H3K4 tri-methylation (H3K4me3), and RNA polymerase II (RNAPII) occupancy by chromatin immunoprecipitation 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 (Gja1, Fos, Oxtr, Ptgs2), are upregulated during active labor due to an increase in transcription at gene bodies. Their promoters and putative intergenic enhancers, however, are epigenetically activated by H3K27ac as early as day 15, four days prior to the onset of active labor on day 19. In fact, we find that the majority of genome-wide H3K27ac or H3K4me3 peaks identified during active labor are present in the myometrium on day 15. Despite the early presence of H3K27ac at labor-associated genes, both an increase in non-coding enhancer RNA (eRNA) production, and in recruitment of RNAPII to corresponding genes occur during active labor, at labor upregulated gene loci. Our findings indicate that epigenetic activation of the myometrial genome precedes active labor by at least four days in the mouse model, suggesting the myometrium is poised for rapid activation of contraction-associated genes in order to exit the state of quiescence.

genomics↗

bioRxiv2019

MicroRNA-transcriptome networks in whole blood and monocytes of women undergoing preterm labor

Preterm birth is attributed to neonatal morbidity as well as cognitive and physiological challenges. We have previously identified significant differences in mRNA expression in whole blood and monocytes, as well as differences in miRNA concentration in blood plasma, extracellular vesicles (EV) and EV-depleted plasma in women undergoing spontaneous preterm labor (sPTL). The goal of this analysis was to identify differences in miRNA expression within whole blood (WB) and peripheral monocytes (PM) from the same population of women undergoing sPTL compared to nonlaboring controls matched by gestational age. We performed single end small RNA sequencing in whole blood and peripheral monocytes from women undergoing sPTL with active contractions(24-34 weeks of gestation, N=15) matched for gestational age to healthy pregnant non laboring controls (>37 weeks gestation, N=30) who later delivered at term as a part of the Ontario Birth Study (Toronto, Ontario CA). We identified significant differences in expression of 16 miRNAs in PMs and 9 miRNAs in WB in women undergoing sPTL. In PMs, these miRNAs were predicted targets of 541 genes, including 28 previously associated with sPTL. In WB, miRNAs were predicted to target 303 genes, including 9 previously associated with sPTL. These genes were involved in a variety of immune pathways, including interleukin 2 signaling. This study is the first to identify changes in miRNA expression in WB and PMs of women undergoing sPTL. Our results shed light on potential mechanisms by which miRNAs may play a role in mediating systemic inflammatory response in pregnant women that deliver prematurely.

systems biology↗