Biology subjects

BAGCHI, I. C.

Publications and source records attributed to BAGCHI, I. C..

7 recordsLinked to original sources

bioRxiv2026

HIF2α-Regulated Pathways Control Human Extravillous Trophoblast Functions by Modulating Cell-to-Cell Communication Through Extracellular Vesicles

Successful pregnancy in humans requires extravillous trophoblast (EVT) cells to invade the endometrium, remodel maternal tissue, and establish a functional placenta. How trophoblasts communicate with the endometrium to coordinate this remodeling remains poorly understood. We previously demonstrated that human endometrial stromal cells communicate through secreted extracellular vesicles (EVs) at the maternal-fetal interface, but whether trophoblasts engage in reciprocal EV-mediated communication remained unknown. Here, using an in vitro trophoblast stem cell differentiation model, we show that EVT cells secrete EVs carrying protein cargo that regulates endometrial stromal cell remodeling, revealing a previously unrecognized arm of maternal-fetal communication. Hypoxia, a defining feature of early placentation, enhanced EV secretion, EVT differentiation, and trophoblast invasion, and these responses required hypoxia-inducible factor 2 (HIF2). Loss of HIF2 impaired EVT differentiation and significantly reduced EV production. Functionally, EVT-derived EVs altered endometrial stromal cell remodeling, in part through HIF2-regulated cargo proteins including matrix metalloproteinase 2 (MMP2). MMP2 depletion reduced both EVT invasion and EV-mediated stromal remodeling, identifying MMP2 as an important mediator of trophoblast-maternal communication. Strikingly, MMP2 deficiency also redirected trophoblast cell fate toward the syncytiotrophoblast (ST) lineage, accompanied by morphological and molecular genetic hallmarks of syncytialization, revealing an unexpected role for a matrix-remodeling enzyme in trophoblast lineage specification. Together, these findings establish a hypoxia-regulated trophoblast EV signaling pathway that links oxygen sensing to trophoblast differentiation, invasion, and maternal tissue remodeling, and reveal an unexpected connection between extracellular matrix remodeling and trophoblast cell-fate decisions during early placental development.

developmental biology↗

bioRxiv2026

Image-Informed Inverse Finite Element Analysis Reveals Altered Constitutive Behavior Following Controlled Uterine Tissue Remodeling

Purpose: Fibrotic remodeling of the uterus, associated with aging, disease, and environmental exposures, alters collagen organization and tissue stiffness, yet how these changes influence organ-level mechanical behavior remains poorly understood. Glutaraldehyde (GA)-induced collagen crosslinking was used as a controlled surrogate for fibrotic remodeling to determine whether image-informed inverse finite element analysis (iFEA), combined with inflation testing and micro-computed tomography (microCT), could detect and quantify the resulting changes in uterine constitutive behavior. Methods: Murine uteri (n = 6 untreated, n = 6 GA-crosslinked) underwent volume-controlled balloon inflation with simultaneous microCT imaging to quantify deformation of the inner and outer wall boundaries for iFEA. Specimen-specific Gasser-Ogden-Holzapfel (GOH) finite element models were optimized by adjusting model parameters to reproduce experimentally measured wall contours throughout inflation. Model performance was evaluated using contour root mean square error (RMSE), and parameter identifiability was assessed through sensitivity analyses. Results: GA treatment significantly increased inflation work, linear stiffness, and maximum inflation resistance (p < 0.001). The iFEA framework accurately reproduced experimental deformation (RMSE < 3%) and revealed significant increases in the estimated GOH parameters C10 (9.2-fold), k1 (2.0-fold), and k2 (2.7-fold), consistent with increased effective tissue stiffness and a shift toward earlier collagen fiber recruitment. Sensitivity analyses demonstrated unique, well-defined minima for all parameter combinations. Conclusion: Image-informed iFEA provides a quantitative framework for relating collagen remodeling to organ-level uterine mechanics through specimen-specific constitutive parameter estimation. This approach establishes a foundation for investigating the mechanical consequences of uterine fibrosis and other remodeling processes.

bioengineering↗

bioRxiv2026

Loss of Glucose Transporter 1 in Mouse Uterine Cells Disrupts Trophoblast Differentiation and Promotes Gestational Diabetes

A successful pregnancy hinges on a finely coordinated dialogue between the maternal endometrium and the implanting embryo. Following embryo attachment to the uterine epithelium, underlying stromal cells undergo a transformation into decidual cells that promote a vascularized maternal-fetal interface and direct trophoblast lineage decisions through paracrine cues. However, the metabolic adaptations that enable decidual cells to support these energetically demanding processes remain poorly understood. Here, using a uterine-specific knockout mouse model, we identify Glucose Transporter 1 (Glut1) as a critical metabolic regulator linking endometrial glucose uptake to reproductive success. We demonstrate that stromal Glut1, induced by hypoxia-inducible factor 2 (Hif2), sustains a Hif2-Rab27b feed-forward circuit that drives vesicular trafficking during pregnancy through the glucose-sensing transcription factor MAX-like protein X (Mlx). Mice lacking endometrial Glut1 are severely subfertile despite normal embryo attachment. Glut1-deficient uteri exhibit impaired stromal extracellular vesicle secretion, defective decidual angiogenesis, and marked dysregulation of trophoblast differentiation, including expansion of trophoblast progenitors, accumulation of glycogen trophoblast cells, and altered placental lactogen production. These placental defects culminate in mid-gestation fetal loss and maternal gestational diabetes mellitus (GDM). Collectively, our findings establish endometrial Glut1 as a metabolic gatekeeper of maternal glucose homeostasis and placentation and introduce a genetically tractable mouse model of spontaneously developing GDM, a disorder affecting nearly one in seven pregnancies worldwide. SIGNIFICANCEThis study uncovers endometrial Glut1 as a previously unrecognized metabolic regulator of placentation, demonstrating that maternal stromal glucose uptake dictates trophoblast fate and maternal glycemic control, and providing the field with its first genetically defined mouse model of spontaneously arising gestational diabetes.

physiology↗

bioRxiv2024

Impact of Paraben on Uterine Collagen: An Integrated and Targeted Correlative Approach Using Second Harmonic Generation Microscopy, Nanoindentation, and Atomic Force Microscopy

This study investigates the structural and mechanical changes in uterine collagen following exposure to propylparaben (PP), using a combined methodology of Second Harmonic Generation (SHG) microscopy, Nanoindentation (NI), and Atomic Force Microscopy (AFM). SHG analysis identified significant disorganization in collagen fibril orientation in the circumferential layer and heterogeneous distribution of regions with elevated forward to backward ratios (F/B) across all uterine layers due to PP exposure. High F/B can indicate multiple potential fibril-level changes like thickened fibrils, higher crosslinking, fibril disorganization - changes not fully decipherable by SHG alone. Recognizing this limitation, the study employs NI and AFM to provide complementary mechanical and nanoscale insights. NI revealed increased indentation modulus in the exposed uteri, suggesting increased stiffness. Co-registration of the indentation response with SHG parameters uncovered that elevated F/B regions show enhanced mechanical stiffness, suggesting a fibrotic transformation following PP exposure. AFM was specifically performed on regions identified by SHG as having low or high F/B, providing the necessary nanoscale resolution to elucidate the structural changes in fibrils that are likely responsible for the observed alterations. This approach confirmed the presence of disordered and entangled collagen fibrils in the circumferential layer in all regions and an increase in fibril diameter in the high F/B regions in the exposed uteri. Together, these findings demonstrate significant alterations in collagen architecture due to PP exposure, revealing disruptions at both the fiber and fibril levels and highlighting the potential for broader applications of the multi-scale, multi-modal approach in collagenous tissue studies.

bioengineering↗

bioRxiv2024

Long-term dietary exposure to a mixture of phthalates enhances estrogen and beta-catenin signaling pathways, leading to endometrial hyperplasia in mice

Phthalates, synthetic chemicals widely utilized as plasticizers and stabilizers in various consumer products, present a significant concern due to their persistent presence in daily human life. While past research predominantly focused on individual phthalates, real-life human exposure typically encompasses complex mixtures of these compounds. The cumulative effects of prolonged exposure to phthalate mixtures on uterine health remain poorly understood. To address this knowledge gap, we conducted studies utilizing adult female mice exposed to a phthalate mixture for 6 and 12 months through ad libitum chow consumption. We previously reported that continuous exposure to this phthalate mixture for 6 months led to uterine fibrosis. In this study, we show that the exposure, when continued beyond 6 months to 1 year, caused fibrotic uteri to display hyperplasia with a significant increase in gland to stroma ratio. Endometrial hyperplasia is commonly caused by unopposed estrogen action, which promotes increased expression of pro-inflammatory cytokines and chemokines and proliferation of the endometrial epithelial cells. Indeed, RNA sequencing analysis revealed a marked upregulation of several estrogen-regulated genes, Wnt ligands that are involved in oncogenic pathways, as well as chemokines, in phthalate-exposed uterine tissues. Consequently, the exposed uteri exhibited increased proliferation of endometrial epithelial cells, and a heightened inflammatory response indicated by extensive homing of macrophages. Further studies revealed a marked enhancement of the Wnt/{beta}-Catenin signaling pathway, potentially contributing to the development of endometrial hyperplasia. Collectively, this study underscores the significance of understanding the exposure to environmental factors in the pathogenesis of endometrial disorders.

physiology↗

bioRxiv2023

Chronic exposure of mice to phthalates enhances TGF beta signaling and promotes uterine fibrosis

Phthalates are synthetic chemicals widely used as plasticizers and stabilizers in various consumer products. Because of the extensive production and use of phthalates, humans are exposed to these chemicals daily. While most studies focus on a single phthalate, humans are exposed to a mixture of phthalates on a regular basis. The impact of continuous exposure to phthalate mixture on uterus is largely unknown. Thus, we conducted studies in which adult female mice were exposed for 6 months to 0.15 ppm and 1.5 ppm of a mixture of phthalates containing di(2-ethylhexyl) phthalate, di-iso-nonyl phthalate, benzyl butyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, and diethyl phthalate via chow ad libitum. Our studies revealed that consumption of phthalate mixture at 0.15 ppm and 1.5 ppm for 6 months led to a significant increase in the thickness of the myometrial layer compared to control. Further investigation employing RNA-sequencing revealed an elevated transforming growth factor beta (TGF-{beta}) signaling in the uteri of mice fed with phthalate mixture. TGF-{beta} signaling is associated with the development of fibrosis, a consequence of excessive accumulation of extracellular matrix components, such as collagen fibers in a tissue. Consistent with this observation, we found a higher incidence of collagen deposition in uteri of mice exposed to phthalate mixture compared to unexposed controls. Second Harmonic Generation imaging showed disorganized collagen fibers and an increase in uterine stiffness upon exposure to phthalate mixture. Collectively, our results demonstrate that chronic exposure to phthalate mixture can have adverse effects on uterine homeostasis.

physiology↗

bioRxiv2023

Runx1 regulates critical factors that control uterine angiogenesis and trophoblast differentiation during placental development

During early pregnancy in humans and rodents, uterine stromal cells undergo a remarkable differentiation to form the decidua, a transient maternal tissue that supports the growing fetus. It is important to understand the key decidual pathways that orchestrate the proper development of the placenta, a key structure at the maternal-fetal interface. We discovered that ablation of expression of the transcription factor Runx1 in decidual stromal cells in a conditional Runx1-null mouse model (Runx1d/d) causes fetal lethality during placentation. Further phenotypic analysis revealed that uteri of pregnant Runx1d/d mice exhibited severely compromised decidual angiogenesis, and a lack of trophoblast differentiation and migration, resulting in impaired spiral artery remodeling. Gene expression profiling using uteri from Runx1d/d and control mice revealed that Runx1 directly controls the decidual expression of the gap junction protein connexin 43 (also known as GJA1), which was previously shown to be essential for decidual angiogenesis. Our study also revealed a critical role of Runx1 in controlling insulin-like growth factor (IGF) signaling at the maternal-fetal interface. While Runx1-deficiency drastically reduced the production of IGF2 by the decidual cells, we observed concurrent elevated expression of the IGF-binding protein 4 (IGFBP4), which regulates the bioavailability of IGFs thereby controlling trophoblast differentiation. We posit that dysregulated expression of GJA1, IGF2, and IGFBP4 in Runx1d/d decidua contributes to the observed defects in uterine angiogenesis, trophoblast differentiation, and vascular remodeling. This study therefore provides unique insights into key maternal pathways that control the early phases of maternal-fetal interactions within a critical window during placental development. SignificanceA clear understanding of the maternal pathways that ensure coordination of uterine differentiation and angiogenesis with embryonic growth during the critical early stages of placenta formation still eludes us. The present study reveals that the transcription factor Runx1 controls a set of molecular, cellular, and integrative mechanisms that mediate maternal adaptive responses controlling uterine angiogenesis, trophoblast differentiation, and resultant uterine vascular remodeling, which are essential steps during placenta development.

physiology↗