Background Benvitimod (Tapinarof), as a small-molecule topical therapeutical aryl hydrocarbon receptor (AHR)-modulating agent, is in clinical development for treating pso... More
Background Benvitimod (Tapinarof), as a small-molecule topical therapeutical aryl hydrocarbon receptor (AHR)-modulating agent, is in clinical development for treating psoriasis and atopic dermatitis. Benvitimod reduces proinflammatory cytokines in psoriasis by specifically binding and activation of AHR. However, whether benvitimod can inhibit keratinocyte proliferation remains unclear. Minichromosome maintenance protein 6 (MCM6) is a key element of the prereplication complex (pre-RC) assembly which is one of the essential steps in the initiation of DNA replication for cell proliferation. Objectives This study aimed to determine whether benvitimod could reduce the excessive proliferation of psoriatic keratinocytes by inhibiting MCM6. Methods We examined the inhibitory effect of benvitimod on MCM6-mediated proliferation of keratinocytes by HaCaT cells in vitro and an IMQ-induced psoriatic model of mice in vivo. Results Epidermal MCM6 expression was enhanced in the skin lesions of psoriatic patients. The experiments further revealed that MCM6 was required for the proliferation of keratinocytes and governed by the IL-22/STAT3 pathway. In addition, the antiproliferation effect of benvitimod is achieved by the inhibition of p-JAK1 and p-JAK2, which further restrained the activation of STAT3 in keratinocytes. Lastly, benvitimod could repressed imiquimod-induced skin lesions and the expression of epidermal MCM6 and p-STAT3 in mice. Moreover, knockdown of AHR in keratinocytes enhanced the activation of JAK1 and JAK2. Conclusion The findings reveal that benvitimod could decrease MCM6-mediated proliferation of keratinocytes by affecting the JAK/STAT3 pathway, thereby serving as a new treatment modality for psoriasis. Less
Diabetes-related skin problems represent the most common long-term complications in diabetes mellitus patients. These complications, which include diabetic dermopathy, di... More
Diabetes-related skin problems represent the most common long-term complications in diabetes mellitus patients. These complications, which include diabetic dermopathy, diabetic blisters, necrobiosis lipoidica diabeticorum, and eruptive xanthomatosis, may dramatically impair patients’ quality of life and cause long-lasting disability. However, the cellular and molecular mechanisms linking diabetes-related hyperglycemia and skin complications are still incompletely understood. To assess the role of the various skin-cell types in hyperglycemia-induced skin disorders, we performed RNA sequencing-based transcriptome analysis, measuring gene expression patterns in biological replicates in normal- and high glucose-stimulated skin cells. Three primary human skin-cell types were examined, i.e., epidermal keratinocytes, dermal fibroblasts, and dermal microvascular endothelial cells. For each separate cell type, we identified gene expression. Comparing gene abundances and expression levels revealed that transcription profiles exhibit distinct patterns in the three skin-cell types exposed to normal (i.e., physiological) glucose treatment and high (i.e., supraphysiological) glucose treatment. The obtained data indicate that high glucose induced differential gene expression and distinct activity patterns in signaling pathways in each skin-cell type. We are adding these data to the public database in the hope that they will facilitate future studies to develop novel targeted interventions for diabetic skin complications. Less
We present a method to create multi-layered engineered tissue composites consisting of human skin fibroblasts and keratinocytes which mimic skin layers. Three-dimensional... More
We present a method to create multi-layered engineered tissue composites consisting of human skin fibroblasts and keratinocytes which mimic skin layers. Three-dimensional (3D) freeform fabrication (FF) technique, based on direct cell dispensing, was implemented using a robotic platform that prints collagen hydrogel precursor, fibroblasts and keratinocytes. A printed layer of cell-containing collagen was crosslinked by coating the layer with nebulized aqueous sodium bicarbonate. The process was repeated in layer-by-layer fashion on a planar tissue culture dish, resulting in two distinct cell layers of inner fibroblasts and outer keratinocytes. In order to demonstrate the ability to print and culture multi-layered cell-hydrogel composites on a non-planar surface for potential applications including skin wound repair, the technique was tested on a poly(dimethylsiloxane) (PDMS) mold with 3D surface contours as a target substrate. Highly viable proliferation of each cell layer was observed on both planar and non-planar surfaces. Our results suggest that organotypic skin tissue culture is feasible using on-demand cell printing technique with future potential application in creating skin grafts tailored for wound shape or artificial tissue assay for disease modeling and drug testing. Less
