Biology subjects

Meinhardt, G.

Publications and source records attributed to Meinhardt, G..

3 recordsLinked to original sources

bioRxiv2023

NOTCH3 signalling controls human trophoblast stem cell expansion and differentiation

Failures in growth and differentiation of the early human placenta are associated with severe pregnancy disorders such as preeclampsia and fetal growth restriction. However, regulatory mechanisms controlling development of its epithelial cells, the trophoblasts, remain poorly elucidated. Using trophoblast stem cells (TSCs), trophoblast organoids (TB-ORGs) and primary cytotrophoblasts (CTBs) of early pregnancy, we herein show that autocrine NOTCH3 signalling controls human placental expansion and differentiation. NOTCH3 receptor was specifically expressed in proliferative CTB progenitors and its active form, the nuclear NOTCH3 intracellular domain (NOTCH3-ICD), interacted with the transcriptional co-activator Mastermind-like 1 (MAML1). Doxycyclin-inducible expression of dominant-negative MAML1 in TSC lines provoked cell fusion and upregulation of genes specific for multinucleated syncytiotrophoblasts, the differentiated hormone-producing cell type of the placenta. However, progenitor expansion and markers of trophoblast stemness and proliferation were suppressed. Accordingly, inhibition of NOTCH3 signalling diminished growth of TB-ORGs whereas overexpression of NOTCH3-ICD in primary CTBs and TSCs showed opposite effects. In conclusion, the data suggest that canonical NOTCH3 signalling plays a key role in human placental development promoting self-renewal of CTB progenitors.

developmental biology↗

bioRxiv2022

Hippo Signaling Cofactor, WWTR1, at the Crossroads of Human Trophoblast Progenitor Self-Renewal and Differentiation.

Healthy progression of human pregnancy relies on cytotrophoblast progenitor (CTB) self-renewal and their differentiation towards multi-nucleated syncytiotrophoblasts (STBs) and invasive extravillous trophoblasts (EVTs). However, underlying molecular mechanisms that fine-tune CTB self-renewal or direct their differentiation towards STBs or EVTs during human placentation are poorly defined. Here, we show that hippo signaling cofactor WW Domain Containing Transcription Regulator 1 (WWTR1) is a master regulator of trophoblast fate choice during human placentation. Using human trophoblast stem cells (human TSCs), primary CTBs and human placental explants, we demonstrate that WWTR1 promotes self-renewal in human CTBs and is essential for their differentiation to EVTs. In contrast, WWTR1 prevents induction of STB fate in undifferentiated CTBs. Our single-cell RNA-sequencing analyses in first-trimester human placenta along with mechanistic analyses in human TSCs revealed that WWTR1 fine-tunes trophoblast fate by directly regulating Wnt signaling components. Importantly, our analyses of placentae from pathological pregnancies show that extreme preterm birth (gestational time [≤]28weeks) and intrauterine growth restriction along with preeclampsia (IUGR/PE) are often associated with loss of WWTR1 expression in CTBs. In summary, our findings establish a critical importance of WWTR1 at the crossroads of human trophoblast progenitor self-renewal vs. differentiation. It plays positive instructive roles to promote CTB self-renewal and EVT differentiation and safeguards undifferentiated CTBs from obtaining the STB fate. SIGNIFICANCEHuman pregnancy relies on formation of the transient organ placenta and trophoblast cells are the major building blocks of the placenta. A defect in trophoblast progenitor self-renewal or their differentiation is associated with either pregnancy loss or pathological pregnancies, yet underlying molecular mechanisms that regulate trophoblast differentiation are poorly understood. In this study, we discovered that WWTR1, a transcription cofactor and a component of conserved Hippo signaling pathway, optimizes trophoblast progenitor self-renewal and is essential for their differentiation into the invasive extravillous trophoblast cell lineage. Our findings establish WWTR1 as a critical regulator for success in human placentation and progression of a healthy pregnancy.

developmental biology↗

bioRxiv2020

PRG2 and AQPEP are misexpressed in fetal membranes in placenta previa and percreta

The obstetrical conditions placenta accreta spectrum (PAS) and placenta previa are a significant source of pregnancy-associated morbidity and mortality, yet the specific molecular and cellular underpinnings of these conditions are not known. In this study, we identified misregulated gene expression patterns in tissues from placenta previa and percreta (the most extreme form of PAS) compared with control cases. By comparing this gene set with existing placental single-cell and bulk RNA-Seq datasets, we show that the upregulated genes predominantly mark extravillous trophoblasts. We performed immunofluorescence on several candidate molecules and found that PRG2 and AQPEP protein levels are upregulated in both the fetal membranes and the placental disk in both conditions. While this increased AQPEP expression remains restricted to trophoblasts, PRG2 is mislocalized and is found throughout the fetal membranes. Using a larger patient cohort with a diverse set of gestationally aged-matched controls, we validated PRG2 as a marker for both previa and PAS and AQPEP as a marker for only previa in the fetal membranes membranes. Our findings suggest that the extraembryonic tissues surrounding the conceptus, including both the fetal membranes membranes and the placental disk, harbor a signature of previa and PAS that reflects increased trophoblast invasiveness. Summary sentence3SEQ and immunofluorescence reveal that extravillous trophoblast factors, most notably PRG2 and AQPEP, define the diseases placenta previa and placenta accreta spectrum (PAS) in both the chorioamniotic membranes and the placental disk.

pathology↗