Biology subjects

Wann, J.

Publications and source records attributed to Wann, J..

3 recordsLinked to original sources

bioRxiv2026

Lrat-Cre Exhibits Widespread Expression Beyond Hepatic Stellate Cells Across Multiple Tissues

Hepatic stellate cells (HSCs) play a central role in liver fibrosis, shifting from quiescent vitamin A-storing cells to activated, myofibroblast-like cells that secrete collagen and other profibrotic factors1. HSCs have thus become a major focus in liver fibrosis research, and several Cre driver lines have been created to target HSCs in mice. However, early Cre lines had significant limitations. Glial fibrillary acidic protein (Gfap)-Cre labels only a subset of HSCs and also induces recombination in cholangiocytes2. Collagen type I alpha 1 (Col1a1)-Cre and alpha-smooth muscle actin (SMA)-Cre/CreERT2 primarily label activated myofibroblasts and broadly mark portal fibroblasts and vascular smooth muscle cells3,4. Platelet-derived growth factor receptor beta (Pdgfr{beta})-Cre reliably labels HSCs but also recombines pericytes and smooth muscle cells, limiting its specificity5. The introduction of lecithin-retinol acyltransferase (Lrat)-Cre marked a major advance, offering highly specific labeling of quiescent and activated HSCs and rapidly becoming the most widely used driver for HSC tracing and genetic perturbation2. However, the extrahepatic expression of Lrat-Cre remains incompletely understood. This is a critical limitation, given that liver biology is closely coordinated with other organs to maintain systemic metabolism. Addressing these gaps is essential for the accurate interpretation of HSC-specific genetic models in liver biology.

pathology↗

bioRxiv2024

Robust single nucleus RNA sequencing reveals depot-specific cell population dynamics in adipose tissue remodeling during obesity

Single nucleus RNA sequencing (snRNA-seq), an alternative to single cell RNA sequencing (scRNA-seq), encounters technical challenges in obtaining high-quality nuclei and RNA, persistently hindering its applications. Here, we present a robust technique for isolating nuclei across various tissue types, remarkably enhancing snRNA-seq data quality. Employing this approach, we comprehensively characterize the depot-dependent cellular dynamics of various cell types underlying adipose tissue remodeling during obesity. By integrating bulk nuclear RNA-seq from adipocyte nuclei of different sizes, we identify distinct adipocyte subpopulations categorized by size and functionality. These subpopulations follow two divergent trajectories, adaptive and pathological, with their prevalence varying by depot. Specifically, we identify a key molecular feature of dysfunctional hypertrophic adipocytes, a global shutdown in gene expression, along with elevated stress and inflammatory responses. Furthermore, our differential gene expression analysis reveals distinct contributions of adipocyte subpopulations to the overall pathophysiology of adipose tissue. Our study establishes a robust snRNA-seq method, providing novel insights into the biological processes involved in adipose tissue remodeling during obesity, with broader applicability across diverse biological systems.

molecular biology↗

bioRxiv2023

Uncoupling protein 1-driven Cre (Ucp1-Cre) is expressed in the epithelial cells of mammary glands and various non-adipose tissues

ObjectiveUncoupling protein 1 (UCP1), a mitochondrial protein responsible for nonshivering thermogenesis in adipose tissue, serves as a distinct marker for thermogenic brown and beige adipocytes. Ucp1-Cre mice are thus widely used to genetically manipulate these thermogenic adipocytes. However, evidence suggests that UCP1 may also be expressed in non-adipocyte cell types. In this study, we investigated the presence of UCP1 expression in different mouse tissues that have not been previously reported. MethodsWe employed Ucp1-Cre mice crossed with Cre-inducible transgenic reporter Nuclear tagging and Translating Ribosome Affinity Purification (NuTRAP) mice, to investigate Ucp1-Cre expression in various tissues of adult female mice and developing embryos. Tamoxifen-inducible Ucp1-CreERT2 mice crossed with NuTRAP mice were used to assess active UCP1 expression. Immunostaining, RNA analysis, and single-cell/nucleus RNA-seq (sc/snRNA-seq) data analysis were performed to determine the expression of endogenous UCP1 and Ucp1-Cre-driven reporter expression. We also investigated the impact of UCP1 deficiency on mammary gland development and function using Ucp1-knockout (KO) mice. ResultsUcp1-Cre expression was observed in the mammary glands within the inguinal white adipose tissue of female Ucp1-Cre; NuTRAP mice. However, endogenous Ucp1 was not actively expressed as Ucp1-CreERT2 failed to induce the reporter expression in the mammary glands. Ucp1-Cre was activated during embryonic development in various tissues, including mammary glands, as well as in the brain, kidneys, eyes, and ears, specifically in epithelial cells in these organs. While sc/snRNA-seq data suggest potential expression of UCP1 in mammary epithelial cells in adult mice and humans, Ucp1-KO female mice displayed normal mammary gland development and function. ConclusionsOur findings reveal widespread Ucp1-Cre expression in various non-adipose tissue types, starting during early development. These results highlight the importance of exercising caution when interpreting data and devising experiments involving Ucp1-Cre mice.

developmental biology↗