Biology subjects

Baltayeva, J.

Publications and source records attributed to Baltayeva, J..

6 recordsLinked to original sources

bioRxiv2022

Single-cell assessment of trophoblast stem cell-based organoids as human placenta-modeling platforms

The recent discovery of human trophoblast stem cells (hTSC) and techniques allowing for trophoblast organoid (TOrg) culture have established promising approaches for studying human trophoblast development. To validate the accuracy of these models at single-cell resolution, we directly compared in vitro TOrg cultures derived from primary progenitor cytotrophoblasts (CTB) or commercially available hTSC lines to in vivo human trophoblasts using a scRNA-seq approach. While patient-derived (PD)- and hTSC-derived TOrgs overall reflect cell differentiation trajectories with accuracy, specific features related to trophoblast state make-up, distinct sub-paths of differentiation, and predicted transcriptional drivers regulating stem cell maintenance were shown to be misaligned in the in vitro platforms. This is best exemplified by the identification of a distinct progenitor state in hTSC-derived TOrgs that showed characteristics of CTB- and extravillous-like cell states. Together, this work provides a comprehensive resource that identifies underlying strengths and limitations of current TOrg platforms. Summary StatementSingle-cell transcriptomics provides comprehensive comparison between trophoblast organoids derived from commercially available trophoblast stem cells and first-trimester primary human cytotrophoblasts. HIGHLIGHTSO_LIAn integrated single cell transcriptomic atlas of placental and organoid trophoblasts establishes a comprehensive and public web-based resource C_LIO_LIDirect comparison of trophoblasts from placental/decidual tissue to trophoblasts extracted from two distinct organoid platforms highlights both conserved and divergent features C_LIO_LIComputational modeling describes novel trophoblast states and routes of cell differentiation in human trophoblast organoids C_LI IN BRIEFWhile the merits and utility of current trophoblast organoid cultures have been established, high-resolution assessment and comparison of conserved and divergent features of these systems to cell states and differentiation trajectories of trophoblasts in situ or in vitro has not been performed. Here, Shannon et al. generate a single-cell transcriptomic atlas of two trophoblast organoids that comprehensively define the similarities and discrepancies in relation to trophoblasts from the placental-maternal interface.

developmental biology↗

bioRxiv2022

Transcriptomic mapping of the metzincin landscape in human trophoblasts

The metzincin family of metalloproteases coordinates cell and tissue developmental processes through regulation of growth factor availability, receptor signaling, and cell-cell/cell-matrix adhesion. During placental development, while distinct roles for metzincin proteases in controlling specific trophoblast functions have been described, a comprehensive assessment of metzincins during discrete stages of trophoblast differentiation has yet to be performed. Here we provide a comprehensive single cell transcriptomic resource of metzincin protease expression in diverse states of human trophoblasts from first trimester placental and decidual tissues. In the 8 distinct trophoblasts states categorized [four progenitor cytotrophoblast (CTB), one syncytiotrophoblast precursor (SCTp), two column CTB (cCTB), and one extravillous trophoblast (EVT) state], we identified 24 metzincin genes. These included 12 adamalysins, 2 pappalysins, 3 astacins and 7 matrixins. Cell trajectory modeling shows that expression of most (19/24) metzincins increases across CTB to EVT differentiation, though select proteases also increase as CTB fuse into syncytiotrophoblast. Within the CTB niche, single-cell velocity ordering identified 11 metzincins (ADAM10, -17, MMP14, -15, -19, -23B, ADAMTS1, -6, -19, TLL-1, -2) expressed in progenitors proximal to the predicted origin. Analysis of metzincin-substrate interactions within the CTB niche revealed [~]150 substrates and binding partners, including FBN2 as an ADAMTS6-specific substrate preferentially expressed in trophoblast progenitors. Together, this work characterizes the metzincin transcriptomic landscape in human first trimester trophoblasts and establishes insight into the roles specific proteases perform within distinct trophoblast niches and across differentiation. This resource serves as a guide for future investigations into the roles of metzincin proteases in human placental development. Summary StatementSingle cell RNA sequencing characterizes the expression of multiple metzincin proteases within first trimester placental trophoblasts. Examination of protease-substrate interactions within cytotrophoblasts identifies potential interactions between ADAMTS6 and FBN2. HighlightsO_LISingle cell RNA sequencing identifies 24 distinct metzincin proteases expressed in human first trimester trophoblasts C_LIO_LILineage trajectory modelling shows that metzincin genes are dynamic and likely control processes in progenitor, mid-point, and end-point states of trophoblast differentiation. C_LIO_LIADAMTS6, and its putative substrate FBN2, localize specifically to progenitor trophoblasts C_LI

developmental biology↗

bioRxiv2022

Decidual innate immune cell kinetics following lipopolysaccharide challenge

In early pregnancy, macrophages (M{varphi}) and natural killer cells (NK) infiltrate and expand within the decidua to comprise 30% of all cellular content. These immune cell populations coordinate angiogenic and tissue remodeling processes that are needed for a healthy pregnancy. Importantly, decidual tissue-resident macrophages (trM{varphi}) and uterine NK retain immunosurveillance properties that facilitate the targeting of infections (e.g., viral, bacterial). The timing and severity of these infections, as well as the resulting immune response, can dictate pregnancy outcome. However, little is known about the kinetics and activities of uterine myeloid and NK populations following infections. To address this knowledge gap, we defined the stepwise changes of uterine myeloid and NK subpopulations following lipopolysaccharide (LPS) challenge in a mouse model of early pregnancy. Low (25 {micro}g/kg), moderate (50 {micro}g/kg), and high (200 {micro}g/kg) doses of LPS resulted in dose-dependent increases in peripheral and uterine inflammation, as well as a dose-dependent increase in the rate of fetal resorption. Compared with saline controls, mice exposed to LPS showed higher frequencies of immature monocytes, decreased TNF-producing monocytes and M{varphi}, and increased conventional (c)NK expression of granzyme B in the uterus. These changes were followed by alterations in overall uterine (u)NK frequencies with increased cNK and decreased tissue resident (tr)NK. Together, this work describes how discrete levels of LPS-induced inflammation shape the innate immune cell landscape of the decidua. These findings establish insight into the stepwise immunological changes following endotoxin challenge and provide a better understanding of how inflammation controls the activity of key decidual leukocytes. Summary sentenceGraded LPS challenge in early pregnancy leads to a stepwise increase in fetal resorption and associates with distinct alterations in frequencies and activities of uterine immune cells.

immunology↗

bioRxiv2021

Single cell trajectory modeling identifies a primitive trophoblast state defined by BCAM enrichment

In early placental development, progenitor cytotrophoblasts (CTBs) differentiate along one of two cellular trajectories: the villous or extravillous pathways. CTBs committed to the villous pathway fuse with neighboring CTBs to form the outer multinucleated syncytiotrophoblast (SCT), while CTBs committed to the extravillous pathway differentiate into invasive extravillous trophoblasts (EVT). Unfortunately, little is known about the processes controlling human CTB progenitor maintenance and differentiation. To address this, we established a single cell RNA sequencing (scRNA-seq) dataset from first trimester placentas to identify cell states important in trophoblast progenitor establishment, renewal, and differentiation. Multiple distinct trophoblast states were identified, representing progenitor CTBs, column CTBs, SCT precursors, and EVT. Lineage trajectory analysis identified a progenitor origin that was reproduced in human trophoblast stem cell organoids. Heightened expression of basal cell adhesion molecule (BCAM) defined this primitive state, where BCAM enrichment or gene silencing resulted in enhanced or diminished organoid growth. Together, this work describes at high-resolution trophoblast heterogeneity within the first trimester, resolves gene networks within human CTB progenitors, and identifies BCAM as a primitive progenitor marker and possible regulator. Summary StatementLineage trajectory modeling identifies multiple human progenitor trophoblast states and defines trophoblast differentiation kinetics, where BCAM-expressing progenitors demonstrate enhanced regenerative ability.

developmental biology↗

bioRxiv2019

Low oxygen enhances trophoblast column growth by potentiating the extravillous lineage and promoting LOX activity

Early placental development and the establishment of the invasive trophoblast lineage take place within a low oxygen environment. However, conflicting and inconsistent findings have obscured the role of oxygen in regulating invasive trophoblast differentiation. In this study, the effect of hypoxic, normoxic, and atmospheric oxygen on invasive extravillous pathway progression was examined using a human placental explant model. Here, we show that exposure to low oxygen enhances extravillous column outgrowth and promotes the expression of genes that align with extravillous trophoblast (EVT) lineage commitment. By contrast, super-physiological atmospheric levels of oxygen promote trophoblast proliferation while simultaneously stalling EVT progression. Low oxygen-induced EVT differentiation coincided with elevated transcriptomic levels of lysyl oxidase (LOX) in trophoblast anchoring columns, where functional experiments established a role for LOX activity in promoting EVT column outgrowth. The findings of this work support a role for low oxygen in potentiating the differentiation of trophoblasts along the extravillous pathway. Additionally, these findings generate insight into new molecular processes controlled by oxygen during early placental development.\n\nSummary StatementLow oxygen promotes extravillous trophoblast differentiation

developmental biology↗

bioRxiv2018

A mouse model of maternal obesity leads to uterine natural killer (uNK) cell activation and uterine artery remodeling defects

Maternal obesity associates with multiple adverse reproductive outcomes, negatively affecting the health and survival of both the mother and the fetus. The contributory effects of obesity on adipose-derived immune changes have been well established, however the mechanisms that link obesity to pregnancy complications remain unclear. Proper development of the placenta and establishment of utero-placental vasculature is essential in early pregnancy to allow for optimal fetal growth and survival. Uterine immune cells, particularly uterine natural killer (uNK) cells, play fundamental roles in promoting these events. Using an obesogenic high-fat/high-sucrose (HFD) mouse model of maternal obesity, uNK cells and placenta/uterine vascular remodeling were examined at gestational days (Gd) 10.5 and 14.5 of pregnancy. While mice fed a HFD 13 weeks prior to pregnancy significantly gained more weight than control mice fed a low-fat/no-sucrose diet (LFD), fetal survival was not different in either diet. At Gd 10.5, HFD had no effect on total uNK proportions, nor did it affect proportions of distinct CD122+/CD49a tissue resident or CD122+/DX5+ conventional uNKs. However, HFD resulted in increased proportions of NCR1+ uNK and overall heightened uNK activity. Moreover, HFD resulted in impairments in uterine vascular remodeling at Gd10.5. By Gd14.5, uterine artery defects were no longer observed and placental structure was comparable between HFD and LFD mice. Gene analysis of IFN{gamma}, TNF and VEGFA in Gd10.5 uNK indicated that, while not significant, a HFD leads to subtle alterations in uNK cytokine gene expression. These findings show that HFD in mice results in changes in uNK biology and temporary uterine artery remodeling impairments. Further, this work establishes insight into the cellular changes occurring in early pregnancy as a result of HFD exposure.

immunology↗