Biology subjects

Bennett, A. Z.

Publications and source records attributed to Bennett, A. Z..

4 recordsLinked to original sources

bioRxiv2026

Endometrial Hyperplasia Risk Is Increased by High-Fat Diet Via Estrogen-Driven Stromal Fibroblast Reprogramming Toward a Pro-Fibrotic State

The uterine endometrium is capable of scarless regeneration under coordinated estrogen and progesterone signaling across the menstrual cycle. Obesity suppresses progesterone production, leading to chronic estrogen exposure and increased endometrial hyperplasia (EH) risk. To define how obesity alters endometrial cell states, endometrial tissues from control and EH-predisposed mice fed either a control diet or a high-fat diet (HFD) were analyzed by single-cell RNA sequencing and tissue phenotyping. HFD reprogrammed endometrial stroma towards an inflammatory, pro-fibrotic state, reducing progesterone receptor-network-associated Aldh1a2+ fibroblasts and expanding estrogen receptor-network-associated Gsn fibroblasts. HFD further impaired macrophage recruitment and promoted hyperplastic epithelial signatures, consistent with increased disease severity in an EH mouse model. Stromal deletion of Estrogen Receptor established stromal estrogen signaling as a driver of HFD-induced extracellular matrix (ECM) accumulation. Collectively, these findings identify HFD-driven fibroblast reprogramming as a central mechanism linking estrogen dominance to stromal fibrosis, defective immune clearance, and heightened EH susceptibility. We propose that, in response to progesterone, fibroblast-mediated ECM remodeling is vital to normal endometrial homeostasis. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=161 SRC="FIGDIR/small/713224v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@1f79ceborg.highwire.dtl.DTLVardef@15f128aorg.highwire.dtl.DTLVardef@ba5604org.highwire.dtl.DTLVardef@16543dc_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO HFD-induced estrogen dominance disrupts endometrial fibroblast homeostasis to predispose the endometrium to diseaseThis study demonstrates that HFD drives estrogen-dependent reprogramming of stromal fibroblasts, characterized by inflammation, stromal ECM accumulation and fibrosis, and a post-ovulatory shift from PGR-network-associated Aldh1a2+ Fibroblasts toward increasing ER-network-associated Gsn+ Fibroblasts. These fibroblast changes are accompanied by a reduction in endometrial macrophages and a transcriptomic shift of HFD epithelium toward hyperplastic epithelium seen in a mouse model of EH. Figure made with BioRender. C_FIG

physiology↗

bioRxiv2026

ULK1 drives NDP52-mediated selective autophagic degradation of MHC-I to promote immune evasion in HPV-positive head and neck cancer

Antigen presentation by major histocompatibility complex class I (MHC-I) is critical for tumor cell killing by CD8+ T cells. Accordingly, tumor cells downregulate MHC-I expression through multiple mechanisms, thereby evading the immune response. Importantly, lower levels of MHC-I are associated with poor responses to immune checkpoint inhibitor therapy. Our recent study has shown that the human papillomavirus (HPV) oncoproteins induce MHC-I protein ubiquitination by membrane-associated Ring-CH-type finger 8 (MARCHF8) in HPV-positive head and neck cancer (HPV+ HNC). However, the mechanism by which ubiquitinated MHC-I is degraded remains elusive. By performing genome-wide CRISPR screens, we identified components of the ULK1 and PIK3C3 complexes for autophagy initiation complexes among the top negative regulators of cell-surface MHC-I expression in HPV+ HNC cells. We show that MHC-I is recruited from the ER to autophagosomes by the cargo receptor NDP52, decreasing MHC-I levels. Further, inhibiting the initiation or nucleation steps of autophagy before autophagosome formation is critical for restoring MHC-I levels on the cell surface. Finally, genetic inhibition of autophagy initiation suppresses HPV+ HNC tumor growth in vivo and enhances the CD8+ T cell-mediated antitumor response. Our findings suggest that autophagic degradation of MARCHF8-ubiquitinated MHC-I is a key immune evasion mechanism in HPV+ HNC.

cancer biology↗

bioRxiv2025

Generation and characterization of a mouse model of conditional Chd4 knockout in the endometrial epithelium.

Chromatin remodeling plays an integral part in endometrial homeostasis, having roles in the maintenance of cell identity, epithelial integrity, and prevention of endometrial disease. Chromodomain-helicase-DNA-binding protein 4 (CHD4) is a chromatin remodeling protein and member of the NuRD complex, which predominantly represses transcription. CHD4 is mutated in endometrial carcinoma, with most mutations leading to loss of function. CHD4 has been identified as a tumor suppressor and regulator of stemness in endometrial carcinoma cells, but little is known about the tissue-specific roles of CHD4 in the endometrial epithelia in vivo. We generated a conditional Chd4 floxed allele and combined it with BAC-Sprr2f-Cre to drive Chd4 loss in the endometrial epithelium. Consistent with previous reports, BAC-Sprr2f-Cre expression is absent in the oviducts, ovaries, and kidneys, and it shows variegated expression within the endometrial epithelium. Loss of CHD4 was confirmed by immunohistochemistry, and stained cells were quantified to determine the percentage of endometrial epithelial cells with and without CHD4. Compared to the glandular epithelium, the extent of CHD4 loss was higher in the luminal epithelium and unaffected by age. Mice with conditional knockout of Chd4 had normal endometrial histology. A 6-month breeding trial was performed to assess the functional effects of endometrial epithelial Chd4 loss on fertility. No difference in litter size, mean number of pups per litter per dam, or pup weight was found between genotypes. These findings demonstrate that Chd4 conditional loss using BAC-Sprr2f-Cre is not sufficient to alter the structure and function of the endometrial epithelium or drive tumorigenesis. As CHD4 is frequently co-mutated with other cancer driver genes such as TP53, PIK3CA, and PTEN, future mouse modeling efforts emulating patient mutational profiles might provide insight into the role of CHD4 in endometrial carcinoma.

developmental biology↗

bioRxiv2024

Unraveling the Molecular Landscape of Uterine Fibroids, Insights into HMGA2 and Stem Cell Involvement

Uterine fibroids are prevalent benign tumors in women that exhibit considerable heterogeneity in clinical presentation and molecular characteristics, necessitating a deeper understanding of their etiology and pathogenesis. HMGA2 overexpression has been associated with fibroid development, yet its precise role remains elusive. Mutations in fibroids are mutually exclusive and largely clonal, suggesting that tumors originate from a single mutant cell. We explored a possible role for HMGA2 overexpression in differentiated myometrial cells, hypothesizing its potential to induce a stem cell-like or dedifferentiating phenotype and drive fibroid development. Myometrial cells were immortalized and transduced with an HMGA2 lentivirus to produce HMGA2hi cells. In vitro stem cell assays were conducted and RNA from HMGA2hi and control cells and fibroid-free myometrial and HMGA2 fibroid (HMGA2F) tissues were submitted for RNA-sequencing. HMGA2hi cells have enhanced self-renewal capacity, decreased proliferation, and have a greater ability to differentiate into other mesenchymal cell types. HMGA2hi cells exhibit a stem cell-like signature and share transcriptomic similarities with HMGA2F. Moreover, dysregulated extracellular matrix pathways are observed in both HMGA2hi cells and HMGA2F. Our findings suggest that HMGA2 overexpression drives myometrial cells to dedifferentiate into a more plastic phenotype and underscore a pivotal role for HMGA2 in fibroid pathogenesis.

molecular biology↗