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• Chronic diesel particulate extract (DPE)/its vapor cause global proteomic changes. • DPE/DPE vapor alter skin integrity related proteins in primary skin keratinocytes. • DPE vapor affects OXPHOS and cell migration associated proteins in skin cells. • DPE/DPE vapor treatment in 3D skin recapitulates their effects on 2D culture. • Vitamin E partially restores altered proteins in DPE/vapor exposed cells. Skin acts as a protective barrier against direct contact with pollutants but inhalation and systemic exposure have indirect effect on keratinocytes. Exposure to diesel exhaust has been linked to increased oxidative stress. To investigate global proteomic alterations in diesel particulate extract (DPE)/ its vapor exposed skin keratinocytes. We employed Tandem Mass Tag (TMT)-based proteomics to study effect of DPE/ DPE vapor on primary skin keratinocytes. We observed an increased expression of oxidative stress response protein NRF2, upon chronic exposure of primary keratinocytes to DPE/ its vapor which includes volatile components such as polycyclic aromatic hydrocarbons (PAHs). Mass spectrometry-based quantitative proteomics led to identification 4490 proteins of which 201 and 374 proteins were significantly dysregulated (≥1.5 fold, p ≤ 0.05) in each condition, respectively. Proteins involved in cellular processes such as cornification (cornifin A), wound healing (antileukoproteinase) and differentiation (suprabasin) were significantly downregulated in primary keratinocytes exposed to DPE/ DPE vapor. These results were corroborated in 3D skin models chronically exposed to DPE/ DPE vapor. Bioinformatics analyses indicate that DPE and its vapor affect distinct molecular processes in skin keratinocytes. Components of mitochondrial oxidative phosphorylation machinery were seen to be exclusively overexpressed upon chronic DPE vapor exposure. In addition, treatment with an antioxidant like vitamin E partially restores expression of proteins altered upon exposure to DPE/ DPE vapor. Our study highlights distinct adverse effects of chronic exposure to DPE/ DPE vapor on skin keratinocytes and the potential role of vitamin E in alleviating adverse effects of environmental pollution. [ABSTRACT FROM AUTHOR]

Highlights • Chronic exposure to diesel particulate extract/ its vapor cause global proteomic alterations in primary skin keratinocytes. • DPE/DPE vapor alter proteins involved in maintaining skin integrity in primary skin keratinocytes. • DPE vapor affects proteins associated with OXPHOS and cell migration in skin keratinocytes. • Similar effects are observed upon DPE/DPE vapor treatment in 2D and 3D skin model. • Vitamin E partially restores altered proteins in DPE/vapor exposed skin keratinocytes. Abstract Background Skin acts as a protective barrier against direct contact with pollutants but inhalation and systemic exposure have indirect effect on keratinocytes. Exposure to diesel exhaust has been linked to increased oxidative stress. Objective To investigate global proteomic alterations in diesel particulate extract (DPE)/its vapor exposed skin keratinocytes. Methods We employed Tandem Mass Tag (TMT)-based proteomics to study effect of DPE/DPE vapor on primary skin keratinocytes. Results We observed an increased expression of oxidative stress response protein NRF2, upon chronic exposure of primary keratinocytes to DPE/its vapor which includes volatile components such as polycyclic aromatic hydrocarbons (PAHs). Mass spectrometry-based quantitative proteomics led to identification 4490 proteins of which 201 and 374 proteins were significantly dysregulated (≥1.5 fold, p ≤ 0.05) in each condition, respectively. Proteins involved in cellular processes such as cornification (cornifin A), wound healing (antileukoproteinase) and differentiation (suprabasin) were significantly downregulated in primary keratinocytes exposed to DPE/DPE vapor. These results were corroborated in 3D skin models chronically exposed to DPE/DPE vapor. Bioinformatics analyses indicate that DPE and its vapor affect distinct molecular processes in skin keratinocytes. Components of mitochondrial oxidative phosphorylation machinery were seen to be exclusively overexpressed upon chronic DPE vapor exposure. In addition, treatment with an antioxidant like vitamin E partially restores expression of proteins altered upon exposure to DPE/DPE vapor. Conclusions Our study highlights distinct adverse effects of chronic exposure to DPE/DPE vapor on skin keratinocytes and the potential role of vitamin E in alleviating adverse effects of environmental pollution. [ABSTRACT FROM AUTHOR]

Dicer is a crucial RNase III enzyme in miRNA biogenesis pathway. Although numerous studies have been carried out to investigate the role of miRNAs and Dicer in the regulation of biological processes, few studies have examined proteomic alterations upon knockout of Dicer. We employed a Cre--loxP-based inducible knockout mouse system to investigate the proteome regulated by Dicer-dependent miRNAs. We utilized spiked liver lysates from metabolically labeled mice to quantify the subtle changes in the liver proteome upon deletion of Dicer. We identified 2137 proteins using high resolution tandem mass spectrometry analysis. The upregulated proteins included several enzymes involved in peroxisomal β-oxidation of fatty acids and a large majority of the upregulated proteins involved in lipid metabolism were known PPARα targets. MRM-based assays were carried out to confirm the upregulation of enzymes including peroxisomal bifunctional enzyme, phosphoenolpyruvate carboxykinase 1, cytochrome P450 3A13, cytochrome P450 3A41 and myristoylated alanine-rich protein kinase C substrate. Further, miRNA-124 which is predicted to regulate expression of peroxisomal bifunctional enzyme was confirmed to be downregulated in the Dicer knockout mice. Our study demonstrates the strength of coupling knockout mouse models and quantitative proteomic strategies to investigate functions of individual proteins in vivo. [ABSTRACT FROM AUTHOR]