Biology subjects

Twigger, A.-J.

Publications and source records attributed to Twigger, A.-J..

4 recordsLinked to original sources

bioRxiv2025

Integrated omics analysis reveals human milk oligosaccharide biosynthesis programs in human lactocytes

Human milk oligosaccharides (HMOs) are integral to infant health. Yet, their complex biosynthesis pathways in the mammary gland during lactation remain under characterized. To address this knowledge gap, we performed integrated analyses of single-cell RNA-sequencing (scRNA-seq) datasets combined with select HMO concentration measures. We identify differential expression patterns of known HMO synthesis genes in epithelial subsets and nominate several candidate genes that vary with HMO concentration. Additionally, we identify novel gene patterns and transcription factors that may regulate the expression of HMO biosynthesis genes and the cellular pathways supporting HMO production. Finally, we demonstrate that co-expression of HMO synthesis genes and milk fat synthesis genes is limited, suggesting distinct epithelial cell subtypes may be responsible for the production of different milk components. Our study suggests that HMO synthesis may be achieved through cell type specialization within the lactocyte compartment.

systems biology↗

bioRxiv2023

A Human Breast Cell Atlas Mapping the Homeostatic Cellular Shifts in the Adult Breast

One of the barriers for breast cancer prevention and treatment is our poor understanding of the dynamic cellular shifts that naturally occur within the breast and how these changes contribute to tumour initiation. In this study we report the use of single cell RNA sequencing (scRNAseq) to compile a Human Breast Cell Atlas (HBCA) assembled from 55 donors that had undergone reduction mammoplasties or risk reduction mammoplasties. The data from more than 800,000 cells identified 41 cell subclusters distributed across the epithelial, immune, and stromal compartments. We found that the contribution of these different clusters varied according to the natural history of the tissue. Breast cancer risk modulating factors such as age, parity, and germline mutation affected the homeostatic cellular state of the breast in different ways however, none of the changes observed were restricted to any one cell type. Remarkably, we also found that immune cells from BRCA1/2 carriers had a distinct gene expression signature indicative of potential immune exhaustion. This suggests that immune escape mechanisms could manifest in non-cancerous tissues during very early stages of tumour initiation. Therefore, the Atlas presented here provides the research community with a rich resource that can be used as a reference for studies on the origins of breast cancer which could inform novel approaches for early detection and prevention.

cancer biology↗

bioRxiv2021

A strategy to address dissociation-induced compositional and transcriptional bias for single-cell analysis of the human mammary gland

Single-cell transcriptomics provide insights into cellular heterogeneity and lineage dynamics that are key to better understanding normal mammary gland function as well as breast cancer initiation and progression. In contrast to murine tissue, human mammary glands require laborious dissociation protocols to isolate single cells. This leads to unavoidable procedure-induced compositional and transcriptional bias. Here, we present a new strategy on how to identify and minimize systematic error by combining different tissue dissociation strategies and then directly comparing composition and transcriptome of isolated cells using single-cell RNA sequencing and flow cytometry. Depending on the tissue isolation strategy, we found dramatic differences in abundance and heterogeneity of certain stromal cells types. Moreover, we identified lineage-specific dissociation-induced gene expression changes that, if left unchecked, could lead to misinterpretation of cellular heterogeneity and, since the basal epithelial population is particularly affected by this, wrongful assignment of putative stem cell populations.

cell biology↗

bioRxiv2020

Transcriptional changes in the mammary gland during lactation revealed by single cell sequencing of cells from human milk

Findings from epidemiological studies suggest that breast cancer risk is influenced by parity in an age-dependent manner. However, human mammary tissue remodelling that takes place during pregnancy and lactation remain little understood due to the challenge of acquiring samples. Here, we present an approach to overcome this using single-cell RNA sequencing to examine viable primary mammary epithelial cells isolated from human milk compared to resting, non-lactating breast tissue. Thereby, we determined that separate to breast tissue, human milk largely contains epithelial cells belonging to the luminal lineage, as well as immune cells. Our data reveal the presence of two distinct secretory luminal cell clusters in milk which highly express luminal progenitor signatures akin to non-lactating breast tissue luminal cells. Taking advantage of the fact that both the resting and lactating mammary gland contain a luminal compartment, we focussed on comparing these transcriptomes and identified differences in mammary cell function and metabolism between these maturation states. These findings provide the basis to dissect human luminal differentiation and milk biosynthesis pathways that in the future, may be interrogated to determine how parity influences luminal cell metabolism and breast cancer risk.

cell biology↗