Biology subjects

Frolova, A.

Publications and source records attributed to Frolova, A..

8 recordsLinked to original sources

bioRxiv2026

Spatial Logic and Evolutionary Innovation in Human Placentation

Human pregnancy unfolds in a unique mosaic tissue context. Embryonic/fetal placental and maternal uterine cells (decidua basalis) coalesce, forming the basal plate where immune tolerance is coordinated and the utero-placental circulation is initiated. The remaining approximately 70% of the maternal-fetal interface is comprised of the chorionic membranes, an epithelial-like layer of placental cells that lies adjacent to but does not coalesce with the overlying decidua capsularis and parietalis. It is unknown how these two regions of the maternal-fetal interface, which are comprised of seemingly similar cell types, diverge anatomically and functionally. Likewise, it is unknown whether the molecular characteristics of the maternal-fetal interface vary across human populations, potentially contributing to population disparities in pregnancy complications. Here, we generated large-scale paired single-nucleus RNA-seq and chromatin-accessibility profiles of the basal plate and chorionic membranes-associated decidual compartments from diverse-ancestry pregnancies, integrated with spatial transcriptomics and multiplexed protein imaging. We show that the two interfaces share a conserved cytotrophoblast differentiation hierarchy, which is deployed differently resulting in the observed distinct architectures. In the chorionic membranes, progenitor, early, and mature extravillous cytotrophoblast (EVT) states form an epithelial-like laminar shell. In the basal plate, this hierarchy is elaborated upon to enable deep placentation: EVTs that arise early in pregnancy invade the farthest into the uterus, while mature EVTs accumulate superficially to sculpt the local maternal immune microenvironment. Comparative analysis identified DSC4, a decidual stromal cell subtype, as an anti-invasive barrier that is densely enriched adjacent to the chorionic membranes but substantially reduced at the basal plate. Population-resolved analysis further identified the DSC4 marker NID2, which encodes the basement-membrane glycoprotein nidogen-2, as an ancestry-associated rheostat of EVT invasion. A specific NID2 promoter haplotype arose on the modern-human lineage, is absent from available archaic-human genomes, and shows evidence of positive selection in Eurasian populations. This haplotype is associated with reduced local chromatin accessibility and lower NID2 expression in DSC4 cells. Consistent with this genetic association, extracellular NID2 directly suppressed the invasion of primary human cytotrophoblasts in vitro. Together, these findings reveal how a shared developmental program is spatially reconfigured across distinct regions of the maternal-fetal interface and identify a recent modern-human regulatory innovation that modulates maternal decidual restraint of fetal trophoblast invasion across populations.

genomics↗

bioRxiv2025

WxS-QC - a quality control pipeline for human Whole-Genome and Whole Exome sequencing cohorts

MotivationWhole-exome (WES) and whole-genome (WGS) sequencing are rapidly becoming preferred methods for population-scale analysis of the human genetic landscape. However, there are currently no standardized quality control (QC) pipelines for human WES and WGS datasets. Moveover, there are no open datasets that can be used to test QC pipelines, because most projects (like 1000 genomes and gnomAD) publish only post-QC results. ResultsWe present WxS-QC, a powerful, scalable, and convenient pipeline for the QC of human WGS and WES cohorts, developed at the Wellcome Sanger Institute (WSI). Our pipeline is based on a deep refactoring of the gnomAD quality control pipeline code and is aligned with current best practices in WGS/WES cohort data QC. It offers a set of novel QC techniques, automatic export of resulting graphs and summary tables, excellent performance and scalability, and incorporates comprehensive documentation. To test our pipeline and similar solutions, we also assembled an open dataset with all required metadata. Availability and implementationThe pipeline code is written in Python using the Hail library and is freely available under the BSD-3 license here: https://github.com/wtsi-hgi/wxs-qc. It can run in any UNIX-like environment and has been able to efficiently process cohorts of up to 200,000 whole-exome samples with the potential to handle bigger datasets, depending on the available hardware. The detailed description of the pipeline, resources and test data is available in the pipeline documentation: https://github.com/wtsi-hgi/wxs-qc/blob/main/README.md The open test dataset is available to download from https://wxs-qc-data.cog.sanger.ac.uk/wxs-qc_public_dataset_v3.tar. An example of test dataset analysis is available in the supplementary materials.

bioinformatics↗

bioRxiv2025

Butyrate Rescues Cardiac Metabolic Dysfunction in Hypertensive Heart Failure with Preserved Ejection Fraction

Diastolic dysfunction in heart failure with preserved ejection fraction (HFpEF) is characterized by metabolic inflexibility. Unlike systolic heart failure, where ketone bodies support energy homeostasis, the failing heart in HFpEF lacks well-characterized alternative fuels to meet its high ATP demand. Here, we show that butyrate, a microbiota-derived short-chain fatty acid, serves as an ancillary energy source and improves diastolic function. Although cardiac power was preserved in rats with HFpEF, both experimental and human HFpEF hearts exhibited an impaired expression of proteins in mitochondrial electron transport chain and oxidative phosphorylation. Additionally, accumulation of 3-hydroxy-butyrate (BOH) in rat and also human HFpEF indicated that ketones do not rescue the cardiac energetic deficit. In HFpEF patients from the UK Biobank, higher BOH levels were associated with increased mortality, particularly those with hypertension. Applying 13C-butyrate to isolated perfused hearts with and without HFpEF resulted in isotope incorporation in butyryl-CoA and downstream TCA intermediates and thus proving its active metabolization. Butyrate was efficiently oxidized by cardiomyocytes and was overtaking BOH and amino acids in supporting respiration. Finaly, chronic butyrate supplementation improved survival, enhanced diastolic function, and reduced fibrosis and inflammation in HFpEF rats despite persistent hypertension. These findings identify butyrate as a compensatory fuel and a promising therapeutic candidate in energetically compromised HFpEF.

biochemistry↗

bioRxiv2023

Development and evaluation of a wearable peripheral vascular compensation sensor in a swine model of hemorrhage

Postpartum hemorrhage (PPH) is both the leading and most preventable cause of maternal mortality. PPH is currently diagnosed through visual estimation of blood loss or vital sign analysis of shock index (ratio of heart rate to systolic blood pressure). Visual assessment underestimates blood loss, particularly in the setting of internal bleeding, and compensatory mechanisms stabilize hemodynamics until hemorrhage is massive, beyond the point of pharmaceutical intervention. Quantitative monitoring of hemorrhage-induced compensatory processes, such as the constriction of peripheral vessels to shunt blood to the central organs, may provide an early alert for PPH. To this end, we developed a low-cost, wearable optical device that continuously monitors peripheral perfusion via laser speckle flow index (LSFI) to detect hemorrhage-induced peripheral vasoconstriction. The device was first tested using flow phantoms across a range of physiologically relevant flow rates and demonstrated a linear response. Subsequent testing occurred in swine hemorrhage studies (n=6) by placing the device on the posterior side of the swines front hock and withdrawing blood from the femoral vein at a constant rate. Resuscitation with intravenous crystalloids followed the induced hemorrhage. The mean LSFI vs. percent estimated blood volume loss had an average correlation coefficient of -0.95 during the hemorrhage phase and 0.79 during resuscitation, both of which were superior to the performance of the shock index. With continued development, this noninvasive, low-cost, and reusable device has global potential to provide an early alert of PPH when low-cost and accessible management strategies are most effective, helping to reduce maternal morbidity and mortality from this largely preventable problem.

bioengineering↗

bioRxiv2022

Disturbed trophoblast transition links preeclampsia progression from placenta to the maternal syndrome

Pre-eclampsia (PE) is a syndrome that affects multiple organ systems and is the most severe hypertensive disorder in pregnancy. It frequently leads to preterm delivery, maternal and fetal morbidity and mortality and life-long complications1. We currently lack efficient screening tools2, 3 and early therapies4, 5 to address PE. To investigate the early stages of early onset PE, and identify candidate markers and pathways, we performed spatio-temporal multi-omics profiling of human PE placentae and healthy controls and validated targets in early gestation in a longitudinal clinical cohort. We used a single-nuclei RNA-seq approach combined with spatial proteo- and transcriptomics and mechanistic in vitro signalling analyses to bridge the gap from late pregnancy disease to early pregnancy pathomechanisms. We discovered a key disruption in villous trophoblast differentiation, which is driven by the increase of transcriptional coactivator p300, that ultimately ends with a senescence-associated secretory phenotype (SASP) of trophoblasts. We found a significant increase in the senescence marker activin A in preeclamptic maternal serum in early gestation, before the development of clinical symptoms, indicating a translation of the placental syndrome to the maternal side. Our work describes a new disease progression, starting with a disturbed transition in villous trophoblast differentiation. Our study identifies potential pathophysiology-relevant biomarkers for the early diagnosis of the disease as well as possible targets for interventions, which would be crucial steps toward protecting the mother and child from gestational mortality and morbidity and an increased risk of cardiovascular disease later in life.

systems biology↗

bioRxiv2019

Global Genetic Cartography of Urban Metagenomes andAnti-Microbial Resistance

We have created a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities across 3 years. This is the first systematic, worldwide study cataloging the urban microbial ecosystem. We identify taxonomically-defined microorganisms collected across three years. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics AMR markers, and novel genetic elements, including 10,928 viral, 1302 bacteria, and 2 archaea novel species. We identify 4,424 species of urban microorganisms and a consistent "core" of 31 species found in nearly all samples that is largely distinct from any human commensal microbiome. Profiles of AMR genes show geographic variation in type and density. Together, these results constitute a high-resolution, global metagenomic atlas, which enables the discovery of new genetic components, highlights potential forensic applications, and provides an essential first draft of the global AMR burden of the worlds cities.

microbiology↗

bioRxiv2017

Creation of gene expression database on preeclampsia-affected human placenta

Publication of gene expression raw data in open access at online resources like NCBI or ArrayExpress made it possible to use these data for cross-experiment integrative analysis and make new insights into biological phenomena. However, most popular of the present online resources are meant to be archives rather than ready for immediate access and interpretation databases. Data uploaded by independent contributors is not standardized and sometimes incomplete and needs further processing before it is ready for the analysis. Hence, the need for a specialized database appears.\n\nGiven in this article is the description of the database that was created after processing a collection of 33 relevant datasets on pre-eclampsia-affected human placenta. Data processing includes the choice of relevant experiments from ArrayExpress database, the experiment sample attributes standardization according to MeSH term dictionary and Experimental Factor Ontology and the completion of missing data using information from the corresponding articles and authors.\n\nA database of more than 1000 samples contains sufficient sample-wise metadata for them to be arranged into relevant case-control groups. Metadata includes information on biological specimen, donors diagnosis, gestational age, mode of delivery etc. The average size of these groups will be higher than it is in separate experiments. This will reduce experiment bias and enhance statistical accuracy of the subsequent analysis such as search for differentially expressed genes or inferring gene networks. The article concludes with the guidelines for the microarray experiment metadata uploading for future contributors.

bioinformatics↗

bioRxiv2017

Designing the database for microarray experiments metadata

Advancements in both computer science and biotechnology opened way to unprecedented amount and variety of gene expression studies raw data in the open access. It is sometimes worth to rearrange and unite data from several similar gene expression studies into new case-control groups to test new hypothesis using available data. Unfortunately, most popular gene expression databases such as GEO and ArrayExpress were not designed to allow such cross-study procedures. In order to locate comparable samples in different studies numerous steps are required including gathering additional sample metadata and its standardization. Specialized databases are developed by investigators in their own fields of interest to reuse the processed data and create different case-control groups and test multiple hypothesis.\n\nHere we present detailed description of the specialized database creation along with its use case which is 32 gene expression cDNA microarray datasets on human placenta under conditions of pre-eclampsia containing expression data on more than 1000 biological samples. Samples contain sufficient metadata for them to be merged into relevant cross-experiment case-control groups for further integrative analysis.

bioinformatics↗