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SZ 95 sebocytes - OLR1 knockdown - treated with UV-oxidized PAPC

ABSTRACT: Human SZ95 sebocytes were transfected by lipofection with either scramble siRNA or OLR1 siRNA and after 24h were treated with 25µg/ml of UV-oxidized 1-palmitoyl-2-arachidonoyl-sn-phosphocholine (UVPAPC) for 7 hours. Phospholipid oxidation products (OxPL) are versatile stress signaling mediators in the skin. These lipid signaling molecules can be generated non-enzymatically or enzymatically by ultraviolet light, the major extrinsic skin aging factor. OxPL regulate cytoprotective, immunological and metabolic adaptation of the skin to oxidant stress. We here investigated whether the scavenger receptor Oxidized Low Density Lipoprotein Receptor 1 (OLR1, LOX-1) would have a function in cutaneous oxPL signaling. We found that OLR1 is expressed in several cutaneous cell types, most prominently in cells of the sebaceous gland and in keratinocytes. We repressed OLR1 expression with siRNA in SZ95 sebocytes, exposed cells to oxidized 1-palmitoyl-2-arachidonoyl-sn-phosphatiylcholine (PAPC) and performed transcriptomic profiling. Bioinformatic analysis revealed that OxPL exposure induced the Nrf2 antioxidant stress response and aldosterone signaling. The analysis also revealed that OLR1 is not required for the transcriptional regulation induced by oxidized PAPC, but interestingly, OLR1 knockdown affected expression of CNN2, HMRR, ITGB6 and KIF20A, all genes governing cell proliferation and motility. We identify sebocytes as cutaneous cells responsive to lipid mediated redox stress which is not dependent on the scavenger receptor OLR1.

ORGANISM(S): Homo sapiens

PROVIDER: GSE98335 | GEO | 2020/04/15

REPOSITORIES: GEO

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Project description:Long wavelength Ultraviolet (UVA-1) radiation causes oxidative stress that leads to the formation of noxious substances within the skin. As a defensive mechanism skin cells produce detoxifying enzymes and antioxidants when they detect modified molecules. We have recently shown that UVA-1 irradiation oxidizes the abundant membrane phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC), which then induced the synthesis of the stress response protein heme oxygenase 1 (HO-1) in dermal fibroblasts. Here we examined the effects of UVA-1 and (UV-) oxidized phospholipids on the global gene expression in human dermal fibroblasts. We identified a cluster of genes that were co-induced by UVA-1-oxidized PAPC and UVA-1 radiation. The cluster included HO-1, glutamate-cysteine ligase modifier subunit (GCLM), aldo-keto reductases-1-C1 and -C2 (AKR1C1, AKR1C2), and interleukin 8 (IL8). These genes are members of the cellular stress response system termed âantioxidant responseâ or âPhase II detoxificationâ. Accordingly, the regulatory regions of all these genes contain binding sites for NF-E2-related factor 2 (Nrf2), a major regulator of the antioxidant response. Both UVA-1 irradiation and treatment with oxidized lipids led to increased nuclear accumulation of Nrf2. Silencing expression of Nrf2 using siRNA or using cells and tissue from Nrf2-deficient mice, we show that the induction of the co-regulated genes was suppressed. Expression of other canonical UVA-1-induced genes, including cyclooxygenase 2 (Cox2) and interleukin 6 (IL6) was unaltered in the absence of Nrf2. Together, our data show that UVA-1-mediated lipid oxidation induces induction of antioxidant response genes, which is dependent on the redox-regulated transcription factor Nrf2. To activate Nrf2 is a major strategy for novel antioxidant drugs, the skin photo-adaptation (SPA) inducers. Our finding that specific uv-oxidized lipids act similar sheds a new (ultraviolet) light on the usually detrimental âimageâ of UV generated lipid mediators. Experiment Overall Design: we profiled global mRNA expression levels in human dermal fibroblasts that had been treated with either UVA-1 or oxidized lipids. To investigate the effect of oxidized phospholipids on gene regulation, we used two preparations, which differed in their degree of oxidation; the minimally oxidized UV-PAPC resulting from UVA-1 irradiation of PAPC, and air-oxidized PAPC (OxPAPC), which represents the full spectrum of oxidation products (Gruber 07) (Reis et al., 2005). We irradiated dermal fibroblasts with UVA-1 (40J/cmÂ²) or treated them with UV-PAPC, OxPAPC or native PAPC (100Âµg/ml each). We analyzed global gene expression four hours after stimulation with gene arrays (Affymetrix U133A Plus 2.0 Gene Chips).

Project description:The transition of the endothelium to a pro-inflammatory state is key to progression of chronic inflammatory diseases including rheumatoid arthritis, chronic bowel disease and atherosclerosis. In atherosclerosis it is hypothesized that low density lipoproteins (LDL) that become trapped in the intima of the blood vessels are oxidized to minimally modified LDL (mmLDL) and that these serve as an important contributing factors to endothelial dysfunction. Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphatidylcholine (OX-PAPC), a model of the active phospholipid components of mmLDL affects the expression of hundreds of genes involved in inflammatory and other biological processes in human aortic endothelial cells (HAECs). We hypothesized that microRNAs (miRNAs) partially regulate this response. Using next generation sequencing, we identified miR-21-3p and miR-27a-5p to be induced 4-fold and 3-fold, respectively in response to OX-PAPC treatment compared to control treatment in HAECs. To identify the targets, we performed whole genome transcript profiling following transient over-expression of these two miRNAs followed by. In total, 1254 genes were down-regulated with 925 of them overlapping between the two miRNAs. Functional enrichment analysis using Gene Ontology predicted that the two miRNAs were involved in the regulation of NF-κB signaling. We characterized the Toll/interleukin-1 receptor (TIR) domain-containing adaptor protein TICAM2 as a direct target of miR-21-3p and miR-27a-5p. Furthermore, we showed that over-expression of miR-21-3p and miR-27a-5p lead to decreased p65 translocation to the nucleus and decreased the expression of known NF-κB downstream target genes confirming both miRNAs’ role in negatively regulating NF-κB signaling in endothelial cells. mRNA expression profiling of human aortic endothelial cells from two separate donors that were transfected with 1 nM microRNA mimics and negative control. The miRIDIAN mimics used were miR-21-3p (Catalog Number:C-301023-01-0005), miR-27a-5p (Catalog No: C-301028-01-0005), negative control (Catalog No: CN-001000-01-05)

Project description:Long wavelength Ultraviolet (UVA-1) radiation causes oxidative stress that leads to the formation of noxious substances within the skin. As a defensive mechanism skin cells produce detoxifying enzymes and antioxidants when they detect modified molecules. We have recently shown that UVA-1 irradiation oxidizes the abundant membrane phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC), which then induced the synthesis of the stress response protein heme oxygenase 1 (HO-1) in dermal fibroblasts. Here we examined the effects of UVA-1 and (UV-) oxidized phospholipids on the global gene expression in human dermal fibroblasts. We identified a cluster of genes that were co-induced by UVA-1-oxidized PAPC and UVA-1 radiation. The cluster included HO-1, glutamate-cysteine ligase modifier subunit (GCLM), aldo-keto reductases-1-C1 and -C2 (AKR1C1, AKR1C2), and interleukin 8 (IL8). These genes are members of the cellular stress response system termed “antioxidant response” or “Phase II detoxification”. Accordingly, the regulatory regions of all these genes contain binding sites for NF-E2-related factor 2 (Nrf2), a major regulator of the antioxidant response. Both UVA-1 irradiation and treatment with oxidized lipids led to increased nuclear accumulation of Nrf2. Silencing expression of Nrf2 using siRNA or using cells and tissue from Nrf2-deficient mice, we show that the induction of the co-regulated genes was suppressed. Expression of other canonical UVA-1-induced genes, including cyclooxygenase 2 (Cox2) and interleukin 6 (IL6) was unaltered in the absence of Nrf2. Together, our data show that UVA-1-mediated lipid oxidation induces induction of antioxidant response genes, which is dependent on the redox-regulated transcription factor Nrf2. To activate Nrf2 is a major strategy for novel antioxidant drugs, the skin photo-adaptation (SPA) inducers. Our finding that specific uv-oxidized lipids act similar sheds a new (ultraviolet) light on the usually detrimental “image” of UV generated lipid mediators.

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SZ 95 sebocytes - OLR1 knockdown - treated with UV-oxidized PAPC

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