Stress In Human Fibroblasts Research Articles

Evaluation of mitochondrial stress following ultraviolet radiation and 5G radiofrequency field exposure in human skin cells.

Whether human cells are impacted by environmental electromagnetic fields (EMF) is still a matter of debate. With the deployment of the fifth generation (5G) of mobile communication technologies, the carrier frequency is increasing and the human skin becomes the main biological target. Here, we evaluated the impact of 5G-modulated 3.5 GHz radiofrequency (RF) EMF on mitochondrial stress in human fibroblasts and keratinocytes that were exposed for 24 h at specific absorption rateof 0.25, 1, and 4 W/kg. We assessed cell viability, mitochondrial reactive oxygen species(ROS) production, and membrane polarization. Knowing that human skin is the main target of environmental ultraviolet (UV), using the same read-out, we investigated whether subsequent exposure to 5G signal could alter the capacity of UV-B to damage skin cells. We found a statistically significant reduction in mitochondrial ROS concentration in fibroblasts exposed to 5G signal at 1 W/kg. On the contrary, the RF exposure slightly but statistically significantly enhanced the effects of UV-B radiation specifically in keratinocytes at 0.25 and 1 W/kg. No effect was found on mitochondrial membrane potential or apoptosis in any cell types or exposure conditions suggesting that the type and amplitude of the observed effects are very punctual.

In vitro protective effects of marine-derived Aspergillus puulaauensis TM124-S4 extract on H2O2-stressed primary human fibroblasts

Nowadays, there is a huge interest in natural products obtained from marine organisms that can promote human health.The aim of the present study is to evaluate for the first time, the in vitro effects of marine Aspergillus puulaauensis TM124-S4 extract against oxidative stress in human fibroblasts, and its potential as a cosmetic ingredient. The strain was isolated from the Mediterranean Sea star, Echinaster sepositus, and identified according to ITS molecular sequence homology as a member of Aspergillus section versicolores.To gain insight on the bioactivity underpinning the effects of TM124-S4 extract on oxidative stress, we examined a panel of a hundred genes as well as cell viability. Initially, Aspergillus puulaauensis TM124-S4 promoted cell viability.The change in gene transcripts revealed that Aspergillus puulaauensis TM124-S4 extracts exhibited skin protection properties by mediating cell proliferation (EPS8, GDF15, CASP7, VEGFA), antioxidant response (CAT, SOD1, TXN, GPX1), skin hydration (CD44, CRABP2, SERPINE) and DNA repair (PCNA, P21). The extract also modulated the expression of genes involved in skin pigmentation and aging (TYR, FOXO3).These findings indicate that Aspergillus puulaauensis TM124-S4 extract possesses significant in-vitro skin protection activity against induced oxidative stress.Furthermore, new insights are provided into the beneficial role of fungal bioactive compounds in skin related research.

Catecholamines Induce Endoplasmic Reticulum Stress Via Both Alpha and Beta Receptors.

Severely burned patients suffer from a hypermetabolic syndrome that can last for years after the injury has resolved. The underlying cause of these metabolic alterations most likely involves the persistent elevated catecholamine levels that follow the surge induced by thermal injury. At the cellular level, endoplasmic reticulum (ER) stress in metabolic tissues is a hallmark observed in patients following burn injury and is associated with several detrimental effects. Therefore, ER stress could be the underlying cellular mechanism of persistent hypermetabolism in burned patients. Here, we show that catecholamines induce ER stress and that adreno-receptor blockers reduce stress responses in the HepG2 hepatocyte cell line. Our results also indicate that norepinephrine (NE) significantly induces ER stress in HepG2 cells and 3T3L1 mouse adipocytes. Furthermore, we demonstrate that the alpha-1 blocker, prazosin, and beta blocker, propranolol, block ER stress induced by NE. We also show that the effects of catecholamines in inducing ER stress are cell type-specific, as NE treatment failed to evoke ER stress in human fibroblasts. Thus, these findings reveal the mechanisms used by catecholamines to alter metabolism and suggest inhibition of the receptors utilized by these agents should be further explored as a potential target for the treatment of ER stress-mediated disease.

Oxidants produced by methylglyoxal-modified collagen trigger ER stress and apoptosis in skin fibroblasts

Methylglyoxal (MG), a highly reactive dicarbonyl, interacts with proteins to form advanced glycation end products (AGEs). AGEs include a variety of compounds which were shown to have damaging potential and to accumulate in the course of different conditions such as diabetes mellitus and aging. After confirming collagen as a main target for MG modifications in vivo within the extracellular matrix, we show here that MG-collagen disrupts fibroblast redox homeostasis and induces endoplasmic reticulum (ER) stress and apoptosis. In particular, MG-collagen-induced apoptosis is associated with the activation of the PERK-eIF2α pathway and caspase-12. MG-collagen contributes to altered redox homeostasis by directly generating hydrogen peroxide and oxygen-derived free radicals. The induction of ER stress in human fibroblasts was confirmed using collagen extracts isolated from old mice in which MG-derived AGEs were enriched. In conclusion, MG-derived AGEs represent one factor contributing to diminished fibroblast function during aging.

Transcriptomic study of high‑glucose effects on human skin fibroblast cells.

Skin ulcers are a common complication of diabetes mellitus (DM). Fibroblasts are located within the dermis of skin tissue and can be damaged by diabetes. However, the underlying mechanism of how DM affects fibroblasts remains elusive. To understand the effects of DM on fibroblasts, the current study mimicked DM by high‑glucose (HG) supplementation in the culture medium of human foreskin primary fibroblast cells, and the analysis of transcriptomic changes was conducted. RNA sequencing‑based transcriptome analysis identified that, upon HG stress, 463 genes were upregulated and 351 genes downregulated (>1.5‑fold changes; P<0.05). These altered genes were distributed into 20 different pathways. In addition, gene ontology (GO) analysis indicated that 31 GO terms were enriched. Among the pathways identified, nuclear factor κB (NF‑κB) pathway genes were highly expressed, and the addition of Bay11‑7082, a typical NF‑κB signaling inhibitor, blocked the previously observed alterations in plasminogen activator inhibitor 1 (PAI1), an inflammation marker and frizzled class receptor 8 (FZD8), a Wnt signaling gene, expression that resulted from HG stress. Furthermore, an inhibitor of Wnt signaling diminished the role of Bay11‑7082 in the regulation of PAI1 expression under HG conditions, suggesting that Wnt signaling may function downstream of the NF‑κB pathway to protect fibroblast cells from HG stress. To the best of our knowledge, the current study is the first analysis of transcriptomic responses under HG stress in human fibroblasts. The data provided here may aid the understanding of the molecular mechanisms by which fibroblast cells are damaged in the skin of patients with DM.

Lipoic acid and acetyl-carnitine reverse iron-induced oxidative stress in human fibroblasts

Iron overload occurs frequently in thalassemia and other disorders that require regular blood transfusions. Excess iron is toxic owing to the generation of free radicals that lead to oxidation of biomolecules and tissue damage. In order to identify compounds that reduce oxidative injury from iron, we evaluated α-lipoic acid (LA), a multifunctional antioxidant, in iron-overloaded primary human fibroblasts (IMR-90). Oxidant stress was measured using dichlorodihydrofluorescein diacetate that is converted to the fluorescent dichlorofluorescein (DCF) upon oxidation. Exposure to ferric ammonium citrate (FAC) increased the iron-content of IMR-90 cells and caused a rise in oxidant appearance. The addition of LA improved the cellular redox status and attenuated the iron-mediated rise in oxidants in a dose-dependent manner. The R- and RS-enantiomers of LA demonstrated similar antioxidant activity. N-tert-butyl hydroxylamine (NtBHA) treated cells also exhibited a decrease in DCF fluorescence, but at a much higher concentration compared with LA. The combination acetyl-L-carnitine (ALCAR) and LA exhibited superior antioxidant effect at all dose levels. We conclude that LA is highly effective in reversing oxidative stress arising from iron overload and that its antioxidant efficacy is further enhanced in combination with ALCAR.

Overexpression of human metallothionein-III prevents hydrogen peroxide-induced oxidative stress in human fibroblasts

Metallothioneins (MT) are ubiquitous low molecular weight metal binding proteins that may act as antioxidants. In the present study, the cloned human MT-III coding region was permanently transfected into GM00637 cells in order to investigate the antioxidative effects of this brain-specific MT isoform. GM00637/MT-III cells overexpressed MT-III mRNA versus pcDNA3 plasmid-transfected control cells (GM00637). When challenged with H 2O 2, the GM00637/MT-III cells displayed significantly more resistance than the GM00637 cells, as determined by cell cytotoxicity, lactate dehydrogenase leakage, and lipid peroxidation. In addition, the GM00637/MT-III cells were highly protected from the H 2O 2-induced production of reactive oxygen species and DNA damage. These results directly support the antioxidative role of MT-III, and demonstrate MT-III can scavenge free oxygen radicals and protect cells from oxidative stress.

Cooperative Induction of c-fosand Heme Oxygenase Gene Products under Oxidative Stress in Human Fibroblastic Cells

Heme oxygenase-1 is a stress responsive enzyme and implicated in a protective function of cellular damage. We investigated cellular events leading to the heme oxygenase-1 gene expression induced by sublethal concentrations of glutathione depletors, phorone and diethyl maleate, in human fibroblastic cells. Accumulation of heme oxygenase-1 mRNA by glutathione depletors was canceled by simultaneous treatment with cycloheximide, an inhibitor of protein synthesis; however, the inhibitory effect decreased when the inhibitor was added 30 min later. Among the inducible early response genes, the c-fosexpression was significantly elevated with a peak at 30 min after the agents. Accumulation of heme oxygenase-1 and c-fostranscripts was abrogated in cells pretreated with 1,4-diazabicyclo[2.2.2]octane, an oxygen-free radical quencher. Decrease in glutathione levels preferentially activated extracellular-signal regulated kinases rather than other stress-activated protein kinases such as c-Jun N-terminal kinases and p38 MAP kinase. Pretreatment of cells with PD 98059, an inhibitor of the extracellular-signal regulated kinase cascade, or the c-fosantisense oligodeoxynucleotide inhibited the heme oxygenase-1 induction elicited by glutathione depletion. These observations indicated that c-Fos protein plays a role in heme oxygenase-1 gene expression induced by glutathione depletion-mediated oxidative stress in human fibroblasts.