Biology subjects

Hutchins, A.

Publications and source records attributed to Hutchins, A..

8 recordsLinked to original sources

bioRxiv2025

Thioredoxin-1 inhibits granulosa cell ferroptosis to rescue ovarian aging through mitophagy-dependent activation of BNIP3L

Ovarian aging is closely associated with a decline in fertility and an increase in reproductive dysfunction. Ovarian granulosa cells (GCs) support oocyte homeostasis and development, yet insight into GC dysfunction during aging is limited. Here, we show that aged GCs of humans and mice have indications of elevated ferroptosis, including increased ferroptosis-related metabolites, lipid peroxidation, and iron accumulation. The ferroptosis inhibitor Ferrostatin-1 reversed ovarian impairment and fertility of aged mice in vivo. We show that the age-related reduction in the expression of TXN (thioredoxin) leads to ferroptosis in human and mouse GCs by blocking BNIP3L-dependent mitophagy. Exogenous activation of TXN could promote mitophagy, thereby clearing excessive ROS and inhibiting ferroptosis. These results suggest that anti-ferroptosis-related treatments may assist in treating aging-related reproductive disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/664497v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1b97e8forg.highwire.dtl.DTLVardef@123f8d0org.highwire.dtl.DTLVardef@a44c61org.highwire.dtl.DTLVardef@92b32e_HPS_FORMAT_FIGEXP M_FIG C_FIG Key pointsO_LIFerroptosis signatures are upregulated in aged GCs from human and mouse ovaries C_LIO_LITXN is deregulated in aged GCs, leading to mitochondrial and ROS metabolic dysfunction C_LIO_LITXN binds to DNA to regulate autophagy and mitophagy genes, including BNIP3L C_LIO_LIInhibition of ferroptosis can ameliorate GC dysfunction C_LI

cell biology↗

bioRxiv2025

Cellular type is a major determinant of R-loop genomic distribution

R-loops containing a DNA:RNA hybrid and unpaired single-stranded DNA are important for normal cell physiology and pathogenesis of numerous diseases. Although several different approaches for R-loop mapping have been developed, these techniques can produce conflicting results. In order to assess their robustness, a study by Chedin et al compared a number of R-loop datasets obtained using different methodologies from normal and cancer cell lines. That study assumed a high degree of similarity between R-loop genomic distributions across different cell types. Here, comparing DRIP datasets produced using the same protocol in different cell lines; we show that only 26 percent of R-loop peaks are common between a chronic myeloid leukemiaderived HAP1 and human pluripotent stem cells, whereas HAP1-derived knockout cell lines share substantial fractions of R-loop peaks with their parental line. We conclude that cellular type represents a major determinant of R-loop genomic distribution and, therefore, only a systematic comparison of a large array of various cell/tissue-types-derived R-loop datasets may address the inconsistencies between different R-loop mapping techniques.

molecular biology↗

bioRxiv2024

BRD8 guards the pluripotent state by sensing and maintaining histone acetylation

Epigenetic control of cell fates is a critical determinant to maintain cell type stability and permissive differentiation. However, the epigenetic control mechanisms are not well understood. Here, we show that the histone acetyltransferase reader protein BRD8 impairs the conversion of primed mouse EpiSCs (epiblast stem cells) to naive mouse ESCs (embryonic stem cells). BRD8 works by maintaining histone acetylation on promoters and transcribed gene bodies. BRD8 is responsible for maintaining open chromatin at somatic genes, and histone acetylation at naive-specific genes. When Brd8 expression was reduced, chromatin accessibility was unchanged, but histone acetylation at primed-specific genes was reduced. Conversely, naive-specific genes had reduced repressive chromatin marks, and acquired accessible chromatin more rapidly during the cell type conversion. We show that this process requires active histone deacetylation to promote the conversion of primed to naive. Our data supports a model for BRD8 reading histone acetylation to accurately localize the genome-wide binding of the histone acetyltransferase KAT5. Overall, this study shows how the reading of the histone acetylation state by BRD8 maintains cell type stability. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/585857v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@199139forg.highwire.dtl.DTLVardef@d735c6org.highwire.dtl.DTLVardef@10b6e15org.highwire.dtl.DTLVardef@16863cf_HPS_FORMAT_FIGEXP M_FIG C_FIG Key findingsO_LIBRD8 blocks the primed-to-naive transition. C_LIO_LIReduced Brd8 promoted the suppression of somatic and primed genes through reduced chromatin repression. C_LIO_LIReduced Brd8 enabled the accelerated activation of naive-specific genes by opening chromatin. C_LIO_LIBRD8 anchors the histone acetyltransferase KAT5 to acetylated genomic loci. C_LI

cell biology↗

bioRxiv2023

coRIC map: a framework for the exploration of multifaceted subcellular RNA-binding proteins

The ability of RNA-binding proteins (RBPs) to form complexes with other biomolecules underpins a broad range of functions and remarkable structural properties. Understanding the precise spatiotemporal dynamics of RBPs and their interacting partners in the steady state and upon perturbation is key to deciphering these aspects. Here, we present the coRIC (compartmentalized RNA Interactome Capture) map, an experimental resource and analytical pipeline to study the subcellular dynamics of RBPs through multimodal dataset integration and machine learning. Using this approach, we have generated an atlas comprising 1,768 RBPs distributed in a broad panel of subcellular compartments and delineated their intermolecular and intercompartmental relationships. We have also defined the hierarchy of RBP-containing complexes at multiple scales across the cell, uncovering previously unknown functions of multiple RBPs. Furthermore, we have investigated the changes in RBP complex composition and subcellular distribution in response to C9ORF72 amyotrophic lateral sclerosis/frontotemporal dementia dipeptide repeats and DNA damage stress. The coRIC map provides a valuable new approach for defining the roles of RBPs in homeostasis and disease.

cell biology↗

bioRxiv2022

Modulating the epigenetic state promotes the reprogramming of transformed cells to pluripotency in a line-specific manner

Somatic cell reprogramming and oncogenic transformation share surprisingly similar features, yet transformed cells are highly resistant to reprogramming. There must be barriers that block transformed cells from reprogramming, but the nature of those barriers is unclear. In this study, we generated a systematic panel of transformed mouse embryonic fibroblasts (MEFs) using a variety of oncogenic transgenes, and discovered transformed cell lines that remain compatible with reprogramming when transfected with Oct4/Sox2/Klf4/Myc. By comparing the reprogramming-capable and incapable transformed lines we identified multiple stages of failure in the reprogramming process. Some transformed lines failed very early, whilst other lines seemed to progress through a normal-looking reprogramming process. Finally, we show that MEK inhibition overcomes one critical reprogramming barrier by indirectly suppressing a hyperactive epigenetic state in some of the transformed cells. This study reveals that the barriers underlying resistance to reprogramming vary between the different transformation methods. Key findingsO_LISomatic cell reprogramming of transformed cells is context-specific C_LIO_LIInhibition of MEK converts some cell lines to reprogramming-capable C_LIO_LITransformed cell lines are characterized by a hyperactive chromatin state C_LIO_LIMEK inhibition indirectly affects chromatin to enable reprogramming C_LI

cell biology↗

bioRxiv2021

A reservoir of stem-like CD8 T cells in the tumor-draining lymph node maintains the ongoing anti-tumor immune response

"Stem-like" TCF1+ CD8+ T cells (TSL) are necessary for long-term maintenance of T cell responses and the efficacy of immunotherapy but, as tumors contain signals that should drive T-cell terminal-differentiation, how these cells are maintained in tumors remains unclear. We found that a small number of TCF1+ tumor-specific CD8+ T cells were present in tumors throughout development. Yet, most intratumoral T cells differentiated as tumors progressed, corresponding with an immunologic shift in the tumor microenvironment (TME) from "hot" to "cold". By contrast, most tumor-specific CD8+ T cells in tumor-draining lymph nodes (dLNs) had functions and gene expression signatures similar to TSL from chronic LCMV infection and this population was stable over time, despite the changes in the TME. dLN T cells were the precursors of their more-differentiated intratumoral counterparts, and maintenance of TCF1 by intratumoral T cells required continuous migration from dLNs. Finally, TSL CD8 T cells were also present in LNs from lung adenocarcinoma patients, suggesting this population is also relevant in human disease. Thus, we propose that the dLN TSL reservoir has a critical function during tumor development in sustaining antitumor T cells during tumor development and protecting them from the terminal differentiation that occurs in the TME.

immunology↗

bioRxiv2020

Transposable Element-Gene Splicing Modulates the Transcriptional Landscape of Human Pluripotent Stem Cells

Transposable elements (TEs) occupy nearly 50% of mammalian genomes and are both potential dangers to genome stability and functional genetic elements. TEs can be expressed and exonised as part of a transcript, however, their full contribution to the transcript splicing remains unresolved. Here, guided by long and short read sequencing of RNAs, we show that 26% of coding and 65% of non-coding transcripts of human pluripotent stem cells (hPSCs) contain TEs. Different TE families have unique integration patterns with diverse consequences on RNA expression and function. We identify hPSC-specific splicing of endogenous retroviruses (ERVs) as well as LINE L1 elements into protein coding genes that generate TE-derived peptides. Finally, single cell RNA-seq reveals that proliferating hPSCs are dominated by ERV-containing transcripts, and subpopulations express SINE or LINE-containing transcripts. Overall, we demonstrate that TE splicing modulates the pluripotency transcriptome by enhancing and impairing transcript expression and generating novel transcripts and peptides.

genomics↗

bioRxiv2020

Unveiling transposable element expression heterogeneity in cell fate regulation at the single-cell level

Transposable elements (TEs) make up a majority of a typical eukaryotes genome, and contribute to cell heterogeneity and fate in unclear ways. Single cell-sequencing technologies are powerful tools to explore cells, however analysis is typically gene-centric and TE activity has not been addressed. Here, we developed a single-cell TE processing pipeline, scTE, and report the activity of TEs in single cells in a range of biological contexts. Specific TE types were expressed in subpopulations of embryonic stem cells and were dynamically regulated during pluripotency reprogramming, differentiation, and embryogenesis. Unexpectedly, TEs were expressed in somatic cells, including human disease-specific TEs that are undetectable in bulk analyses. Finally, we applied scTE to single cell ATAC-seq data, and demonstrate that scTE can discriminate cell type using chromatin accessibly of TEs alone. Overall, our results reveal the dynamic patterns of TEs in single cells and their contributions to cell fate and heterogeneity.

bioinformatics↗