Biology subjects

Frolova, A. I.

Publications and source records attributed to Frolova, A. I..

6 recordsLinked to original sources

bioRxiv2026

Effects of Maternal Obesity on Fetal Cerebral Glucose Transporter Expression

Emerging evidence indicates that the maternal in utero environment has enduring effects on offspring neurodevelopment. The obesity epidemic in the United States affects nearly one-third of women before pregnancy, potentially predisposing offspring to harmful developmental conditions. Glucose, the primary energy source for the brain, is highly regulated by facilitative diffusion glucose transporters (GLUTs). However, our understanding of how maternal obesity influences perinatal cerebral glucose metabolism remains limited. We hypothesized that maternal obesity is associated with altered expression of key GLUTs and dysregulated energy-sensing mechanisms in the fetal brain. Female C57BL/6J mice were randomly assigned to either a control diet (CON) or an obesogenic diet (DIO) (60% kcal from fat, 17.5% kcal from sucrose) for 10 weeks, time-mated with control males, and fed their respective diets throughout gestation. At 18.5 days post coitum, fetal brain tissue was collected for protein analysis. DIO diet did not affect litter size, offspring body weight, or brain weight when compared to CON. Whole brain GLUT1 expression was elevated only in female DIO offspring, while GLUT3 and GLUT4 expression was increased in all DIO offspring without modification by sex. However, maternal diet was not associated with differences in the activation of energy regulatory pathways adenosine monophosphate-activated protein kinase (AMPK) or the nutrient-sensing pathway mechanistic target of rapamycin (mTOR) in the fetal brain. These findings suggest that maternal obesogenic diet alters glucose transporter expression in the fetal brain, indicating a potential disruption in cerebral glucose metabolism during critical periods of perinatal development.

developmental biology↗

bioRxiv2026

EMMIs: Engineered Myometrial Microtissues for Direct Quantification of Oxytocin-Induced Contractility

Forceful and coordinated contractions of the uterine myometrium are essential for successful labor, delivery, and postpartum uterine involution. Failure of the uterus to generate or sustain contractile force (uterine atony) after delivery results in postpartum hemorrhage, a leading cause of maternal mortality globally. Paradoxically, uterine atony is exacerbated by prolonged oxytocin exposure used to induce or augment labor through a process of contractile desensitization. Despite its prevalent use in obstetrics, the direct impact of oxytocin desensitization on myometrial contractile force generation remains poorly defined. Current model systems are inadequate to address this gap: ex vivo myometrial tissue strips are limited by tissue availability, donor variability, and lack of genetic tractability, while existing in vitro models provide only indirect readouts of contractility without direct force quantification. Here, we introduce engineered myometrial microtissues (EMMIs), a platform enabling the direct, isometric measurement of contractile force in response to physiological agonists like oxytocin. By embedding and molding immortalized human myometrial smooth muscle cells within a collagen hydrogel, we induced significant structural and molecular maturation over six days. Upon maturation, EMMIs were characterized by circumferential cellular alignment, sustained expression of smoothelin, upregulation of connexin-43, and a transcriptomic shift toward a contractile phenotype. Mature EMMIs generated calcium-sensitive, dose-dependent contractions to oxytocin and potassium chloride. Genetic deletion of the oxytocin receptor abolished oxytocin-induced contractility, establishing receptor specificity. Finally, we utilized EMMIs to recapitulate clinical oxytocin desensitization, providing a direct link between prolonged oxytocin exposure and diminished contractile output. Together, these findings establish engineered myometrial microtissues (EMMIs) as a genetically manipulable, and reproducible system for investigating myometrial contractile physiology to improve obstetric outcomes. TeaserEngineered 3D uterine tissues quantify how labor-inducing drugs weaken contractions and drive maternal hemorrhage

bioengineering↗

bioRxiv2026

Metabolic Flexibility and Energy Substrate Utilization Regulate Contractility in the Human Myometrium

The uterus requires energy for sustained contractility during labor, to deliver the fetus and diminish the risk of postpartum hemorrhage. Our objective was to define energy requirements and assess metabolic flexibility in quiescent and contractile myometrial cells. Cells were treated with oxytocin to stimulate myometrial contractility. We found that myometrial cells rely on oxidative phosphorylation during quiescence and, when treated with oxytocin, can adapt to higher energy demands by shifting their energy production to glycolysis. Treatment with mitochondrial oxidation inhibitors revealed that in quiescent myometrial cells basal oxygen consumption rate decreased when treated with glucose oxidation inhibitor UK5099, but not the long chain fatty acid oxidation inhibitor etomoxir or the glutamine oxidation inhibitor BPTES. In oxytocin treated myometrial cells, this decrease was also observed upon BPTES treatment in addition to UK5099, suggesting that contractile myometrial cells can shift energy production from glucose to glutamine. Functionally, myometrial contractility was significantly reduced by UK5099 but not by etomoxir, further indicating dependence on glucose utilization.

cell biology↗

bioRxiv2025

PIEZO channels link mechanical forces to uterine contractions in parturition

AbstractMechanical forces are extensively involved in pregnancy and parturition, but their precise roles and mechanisms remain poorly understood. Here, we identify mechanically activated ion channels PIEZO1 and PIEZO2 as key mechanotransducers required for labor progression. Genetic deletion of Piezo1 and Piezo2 in mice resulted in weakened uterine contractions and severe parturition defects. Tissue-specific knockouts revealed that deletion in either the uterus or sensory neurons alone caused modest defects, whereas combined loss significantly impaired labor, demonstrating additive effects. Single-nuclei sequencing showed that loss of PIEZO reduced expression of connexin43 (Gja1), a gap junction protein in uterine smooth muscle cells, suggesting a mechanistic link to impaired contraction. These findings highlight the critical role of PIEZO channels in mechanotransduction during parturition and suggest therapeutic targets for labor dysfunction.

physiology↗

bioRxiv2025

The Sphingosine-1-phosphate pathway is differentially activated in human gestational tissues.

BACKGROUNDDysregulated myometrial contractility contributes to obstetric complications. Sphingosine-1-phosphate (S1P) is an important inflammatory regulator in the myometrium and decidua, yet its metabolic dynamics during pregnancy are poorly characterized. This study aimed to profile the expression of S1P metabolic enzymes and receptors, and quantify sphingolipid metabolism in human gestational tissues across pregnancy. METHODSMyometrium, decidua parietalis, and chorioamnion were collected from women undergoing cesarean sections at term ([≥]37 weeks gestation) without labor (TNL), at term with labor (TL), and preterm (<37 weeks gestation) without labor (PTNL). Messenger RNA (mRNA) expression of S1P metabolic enzymes and receptors was assessed using quantitative polymerase chain reaction, while sphingolipids were quantified using targeted liquid chromatography-tandem mass spectrometry. RESULTSS1P metabolic enzymes and receptors were differentially expressed across gestational tissues. At TNL, SPHK1 expression was significantly higher in the decidua parietalis than in the chorioamnion and myometrium. The myometrium exhibited the highest mRNA expression of S1P receptors (S1PR1-4) compared to the decidua and chorioamnion. At term, S1P was more abundant in the myometrium than in the decidua parietalis and chorioamnion. Both SPHK1 and S1P were significantly increased in TL compared to TNL myometrium. S1P levels were higher in the myometrium at TNL compared to PTNL, while no significant differences were observed in the decidua and chorioamnion. Overall, sphingolipid metabolism was highest in the decidua and myometrium and lowest in the chorioamnion at term. CONCLUSIONThese findings reveal tissue-specific regulation of S1P metabolism and signaling in human gestational tissues, suggesting a therapeutic role of S1P in modulating myometrial contractility.

developmental biology↗

bioRxiv2024

Understanding the effects of oxytocin receptor variants on OXT-OXT receptor binding: A mathematical model

Approximately half of U.S. women giving birth annually receive Pitocin, the synthetic form of oxytocin (OXT), yet its effective dose can vary significantly. This variability presents safety concerns due to unpredictable responses, which may lead to adverse outcomes for both mother and baby. To address the need for improved dosing, we developed a data-driven mathematical model to predict OXT receptor (OXTR) binding. Our study focuses on five prevalent OXTR variants (V45L, P108A, L206V, V281M, and E339K) and their impact on OXT-OXTR binding dynamics in two distinct cell types: human embryonic kidney cells (HEK293T), commonly used in experimental systems, and human myometrial smooth muscle cells, containing endogenous OXTR. We parameterized the model with cell-specific OXTR surface localization measurements. To strengthen the robustness of our study, we conducted a comprehensive meta-analysis of OXT- OXTR binding, enabling parameterization of our model with cell-specific OXT-OXTR binding kinetics (myometrial OXT-OXTR Kd = 1.6 nM, kon = 6.8 x 105 M-1 min-1, and koff = 0.0011 min-1). Our meta-analysis revealed significant homogeneity in OXT-OXTR affinity across experiments and species with a Kd = 0.52 - 9.32 nM and mean Kd = 1.48 {+/-} 0.36 nM. Our model achieves several valuable insights into designing dosage strategies. First, we predicted that the OXTR complex reaches maximum occupancy at 10 nM OXT in myometrial cells and at 1 {micro}M in HEK293T cells. This information is pivotal for guiding experimental design and data interpretation when working with these distinct cell types, emphasizing the need to consider effects for specific cell types when choosing OXTR-transfected cell lines. Second, our model recapitulated the significant effects of genetic variants for both experimental and physiologically relevant systems, with V281M and E339K substantially compromising OXT-OXTR binding capacity. These findings suggest the need for personalized oxytocin dosing based on individual genetic profiles to enhance therapeutic efficacy and reduce risks, especially in the context of labor and delivery. Third, we demonstrated the potential for rescuing the attenuated cell response observed in V281M and E339K variants by increasing the OXT dosage at specific, early time points. Cellular responses to OXT, including Ca2+ release, manifest within minutes. Our model indicates that providing V281M- and E339K-expressing cells with doubled OXT dose during the initial minute of binding can elevate OXT-OXTR complex formation to levels comparable to wild-type OXTR. In summary, our study provides a computational framework for precision oxytocin dosing strategies, paving the way for personalized medicine.

systems biology↗