274 Junctional Epidermolysis Bullosa: Bottom Up Control Of The Skin Barrier?

Abstract

Human Cell Atlas is an international initiative aiming at creating a comprehensive map of all cells in the human body. This project contributes to Skin Atlas in attempt to resolve the population of interfollicular epidermal stem cells (IFE SCs), previously described as homogeneous. These cells are located in the basal layer of the epidermis, which is distinguished by expression of a6 integrin. We used this marker to enrich keratinocytes from human skin for basal cells and perform single-cell RNA sequencing. We found three transcriptionally distinct populations of basal keratinocytes. Two of them showed classic stem cell signature (KRT5, KRT14). The differences between these stem cells were driven by genes associated with immunomodulatory function (CCL2, CXCL14). We compared our results to large published datasets with lower gene coverage and found correlation between keratinocyte heterogeneity and our genes of interest. The third population of basal keratinocytes was enriched in markers of early stem cell commitment (KRT10). The three groups formed a continuous trajectory after pseudotime reconstruction, reflecting IFE SCs differentiation. We used the same approach to address IFE SCs changes in psoriasis, an auto-immune disease with prominent keratinocyte hyperproliferation. We found that basal cells from psoriatic epidermis also have two stem cell sub-populations and one group with early commitment signature. We identified sub-populations of stem cells that are specific to healthy and disease skin and found non-linear pseudotime trajectory of basal cells in psoriasis, suggesting a stem cell state switch in disease. To address this further, we are expanding the study to compare keratinocytes from lesional and non-lesional sites of psoriatic skin. This will provide insight into stem cell role in psoriasis and contribute to the Skin Atlas generation.

Localisation and regulation of cholesterol transporters in the human hair follicle: mapping changes across the hair cycle

“…These cholesterol deposits have been described as both needles and plates ranging from 4 to 50 µm in size (Suhalim et al 2012 ). The cholesterol striations identified in the HF basement membrane may represent an interaction of cholesterol with laminin-332 during cholesterol movement from CTS to ORS (Jones et al 2018 , 2019 ), or deposits of excess cholesterol monohydrate needles, however, additional experiments are required to confirm this.…”

A More Biomimetic Cell Migration Assay with High Reliability and Its Applications

“…Cell migration refers to the movement of cells from one location to another under various stimuli, including shear stress [1], topography [2], oxygen [3], cytokines [4], and extracellular matrix proteins [5]; it is considered as one of the important indicators of the physiological and pathological process, e.g., wound healing [6][7][8][9][10]. There is evidence that during wound healing in tissues, cell migration is essential for the re-epithelialization of the skin [11,12]. However, studies of cell migration in vivo are limited by ethical issues with animal experiments, and thus are only possibly conducted in vitro with engineered devices that mimic the in vivo environments.…”