scholarly journals α-Melanocyte-Stimulating Hormone Counteracts the Suppressive Effect of UVB on Nrf2 and Nrf-Dependent Gene Expression in Human Skin

Endocrinology ◽  
2009 ◽  
Vol 150 (7) ◽  
pp. 3197-3206 ◽  
Author(s):  
Agatha Kokot ◽  
Dieter Metze ◽  
Nicolas Mouchet ◽  
Marie-Dominique Galibert ◽  
Meinhard Schiller ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Human Skin ◽  
Uv Light ◽  
Ex Vivo ◽  
Suppressive Effect ◽  
Heme Oxygenase 1 ◽  
Organ Cultures ◽  
Normal Keratinocytes

Human skin is constantly exposed to UV light, the most ubiquitous environmental stressor. Here, we investigated the expression and regulation of Nrf1-3, transcription factors crucially involved in protection against oxidative stress in human skin cells in vitro, ex vivo, and in situ. In particular, we examined whether α-MSH, a UV-induced peptide, is capable of modulating Nrf2 and Nrf-dependent gene expression. Nrf1, -2, and -3 were found to be expressed in various cutaneous cell types in vitro. Surprisingly, UVB irradiation at physiological doses (10 mJ/cm2) reduced Nrf2 and Nrf-dependent gene expression in normal keratinocytes and melanocytes in vitro as well as ex vivo in skin organ cultures. α-MSH alone significantly increased Nrf2 as well as Nrf-dependent heme oxygenase-1, γ-glutamylcysteine-synthetase, and glutathione-S-transferase Pi gene expression in both keratinocytes and melanocytes. This effect of α-MSH occurred at physiological doses and was due to transcriptional induction, mimicked by the artificial cAMP inducer forskolin, and blocked by protein kinase A pathway inhibition. In silico promoter analysis of Nrf2 further identified several putative binding sites for activator protein 1 and cAMP response element-binding protein, transcription factors typically activated by α-MSH. Importantly, α-MSH prevented or even overcompensated the UVB-induced suppression of Nrf2 and Nrf-dependent genes not only in normal keratinocytes and melanocytes in vitro but also in skin organ cultures. These findings, for the first time, show regulation of Nrf2 and Nrf-dependent genes by α-MSH. Our data also highlight a novel facet in the cytoprotective and antioxidative effector mechanisms of α-MSH and perhaps of related melanocortin peptides.

scholarly journals Delivering nitric oxide into human skin from encapsulated S-nitrosoglutathione under UV light: An in vitro and ex vivo study

Nitric Oxide ◽  
2020 ◽  
Vol 94 ◽  
pp. 108-113 ◽  
Author(s):  
Milena T. Pelegrino ◽  
Richard B. Weller ◽  
André Paganotti ◽  
Amedea B. Seabra
Keyword(s):  
Nitric Oxide ◽  
Human Skin ◽  
Uv Light ◽  
Ex Vivo ◽  
Ex Vivo Study

scholarly journals Ginseng Berry Extract Prevents Atherogenesis via Anti-Inflammatory Action by Upregulating Phase II Gene Expression

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Chun-Ki Kim ◽  
Dong Hui Cho ◽  
Kyu-Sun Lee ◽  
Dong-Keon Lee ◽  
Chan-Woong Park ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phase Ii ◽  
Underlying Mechanism ◽  
Suppressive Effect ◽  
Heme Oxygenase 1 ◽  
Cellular Events ◽  
Atherosclerotic Lesions ◽  
Species Production

Ginseng berry possesses higher ginsenoside content than its root, which has been traditionally used in herbal medicine for many human diseases, including atherosclerosis. We here examined the antiatherogenic effects of the Korean ginseng berry extract (KGBE) and investigated its underlying mechanism of actionin vitroandin vivo. Administration of KGBE decreased atherosclerotic lesions, which was inversely correlated with the expression levels of phase II genes to include heme oxygenase-1 (HO-1) and glutamine-cysteine ligase (GCL). Furthermore, KGBE administration suppressed NF-κB-mediated expression of atherogenic inflammatory genes (TNF-α, IL-1β, iNOS, COX-2, ICAM-1, and VCAM-1), without altering serum cholesterol levels, in ApoE-/-mice fed a high fat-diet. Treatment with KGBE increased phase II gene expression and suppressed lipopolysaccharide-induced reactive oxygen species production, NF-κB activation, and inflammatory gene expression in primary macrophages. Importantly, these cellular events were blocked by selective inhibitors of HO-1 and GCL. In addition, these inhibitors reversed the suppressive effect of KGBE on TNF-α-mediated induction of ICAM-1 and VCAM-1, resulting in decreased interaction between endothelial cells and monocytes. These results suggest that KGBE ameliorates atherosclerosis by inhibiting NF-κB-mediated expression of atherogenic genes via upregulation of phase II enzymes and thus has therapeutic or preventive potential for atherosclerosis.

Anti-Inflammatory Effects of Novel Standardized Platelet Rich Plasma Releasates on Knee Osteoarthritic Chondrocytes and Cartilage in vitro

2019 ◽  
Vol 20 (11) ◽  
pp. 920-933 ◽  
Author(s):  
Lucía Gato-Calvo ◽  
Tamara Hermida-Gómez ◽  
Cristina R. Romero ◽  
Elena F. Burguera ◽  
Francisco J. Blanco
Keyword(s):  
Gene Expression ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Cartilage Explants ◽  
Ex Vivo Model ◽  
Chondrocyte Viability ◽  
Platelet Concentration ◽  
The Absolute ◽  
Anti Inflammatory

Background: Platelet Rich Plasma (PRP) has recently emerged as a potential treatment for osteoarthritis (OA), but composition heterogeneity hampers comparison among studies, with the result that definite conclusions on its efficacy have not been reached. Objective: 1) To develop a novel methodology to prepare a series of standardized PRP releasates (PRP-Rs) with known absolute platelet concentrations, and 2) To evaluate the influence of this standardization parameter on the anti-inflammatory properties of these PRP-Rs in an in vitro and an ex vivo model of OA. Methods: A series of PRPs was prepared using the absolute platelet concentration as the standardization parameter. Doses of platelets ranged from 0% (platelet poor plasma, PPP) to 1.5·105 platelets/µl. PRPs were then activated with CaCl2 to obtain releasates (PRP-R). Chondrocytes were stimulated with 10% of each PRP-R in serum-free culture medium for 72 h to assess proliferation and viability. Cells were co-stimulated with interleukin (IL)-1β (5 ng/ml) and 10% of each PRP-R for 48 h to determine the effects on gene expression, secretion and intra-cellular content of common markers associated with inflammation, catabolism and oxidative stress in OA. OA cartilage explants were co-stimulated with IL-1β (5 ng/ml) and 10% of either PRP-R with 0.75·105 platelets/µl or PRP-R with 1.5·105 platelets/µl for 21 days to assess matrix inflammatory degradation. Results: Chondrocyte viability was not affected, and proliferation was dose-dependently increased. The gene expression of all pro-inflammatory mediators was significantly and dose-independently reduced, except for that of IL-1β and IL-8. Immunoblotting corroborated this effect for inducible NO synthase (NOS2). Secreted matrix metalloproteinase-13 (MMP-13) was reduced to almost basal levels by the PRP-R from PPP. Increasing platelet dosage led to progressive loss to this anti-catabolic ability. Safranin O and toluidine blue stains supported the beneficial effect of low platelet dosage on cartilage matrix preservation. Conclusion: We have developed a methodology to prepare PRP releasates using the absolute platelet concentration as the standardization parameter. Using this approach, the composition of the resulting PRP derived product is independent of the donor initial basal platelet count, thereby allowing the evaluation of its effects objectively and reproducibly. In our OA models, PRP-Rs showed antiinflammatory, anti-oxidant and anti-catabolic properties. Platelet enrichment could favor chondrocyte proliferation but is not necessary for the above effects and could even be counter-productive.

Subnuclear compartmentalization of sequence-specific transcription factors and regulation of eukaryotic gene expression

2005 ◽  
Vol 83 (4) ◽  
pp. 535-547 ◽  
Author(s):  
Gareth N Corry ◽  
D Alan Underhill
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Current Knowledge ◽  
Nuclear Architecture ◽  
Subnuclear Localization ◽  
Modular Structures

To date, the majority of the research regarding eukaryotic transcription factors has focused on characterizing their function primarily through in vitro methods. These studies have revealed that transcription factors are essentially modular structures, containing separate regions that participate in such activities as DNA binding, protein–protein interaction, and transcriptional activation or repression. To fully comprehend the behavior of a given transcription factor, however, these domains must be analyzed in the context of the entire protein, and in certain cases the context of a multiprotein complex. Furthermore, it must be appreciated that transcription factors function in the nucleus, where they must contend with a variety of factors, including the nuclear architecture, chromatin domains, chromosome territories, and cell-cycle-associated processes. Recent examinations of transcription factors in the nucleus have clarified the behavior of these proteins in vivo and have increased our understanding of how gene expression is regulated in eukaryotes. Here, we review the current knowledge regarding sequence-specific transcription factor compartmentalization within the nucleus and discuss its impact on the regulation of such processes as activation or repression of gene expression and interaction with coregulatory factors.Key words: transcription, subnuclear localization, chromatin, gene expression, nuclear architecture.

scholarly journals Cell–cell coupling and DNA methylation abnormal phenotypes in the after-hours mice

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Federico Tinarelli ◽  
Elena Ivanova ◽  
Ilaria Colombi ◽  
Erica Barini ◽  
Edoardo Balzani ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Neuronal Networks ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Neuronal Cultures ◽  
Functional Impairments ◽  
After Hours ◽  
The Impact

Abstract Background DNA methylation has emerged as an important epigenetic regulator of brain processes, including circadian rhythms. However, how DNA methylation intervenes between environmental signals, such as light entrainment, and the transcriptional and translational molecular mechanisms of the cellular clock is currently unknown. Here, we studied the after-hours mice, which have a point mutation in the Fbxl3 gene and a lengthened circadian period. Methods In this study, we used a combination of in vivo, ex vivo and in vitro approaches. We measured retinal responses in Afh animals and we have run reduced representation bisulphite sequencing (RRBS), pyrosequencing and gene expression analysis in a variety of brain tissues ex vivo. In vitro, we used primary neuronal cultures combined to micro electrode array (MEA) technology and gene expression. Results We observed functional impairments in mutant neuronal networks, and a reduction in the retinal responses to light-dependent stimuli. We detected abnormalities in the expression of photoreceptive melanopsin (OPN4). Furthermore, we identified alterations in the DNA methylation pathways throughout the retinohypothalamic tract terminals and links between the transcription factor Rev-Erbα and Fbxl3. Conclusions The results of this study, primarily represent a contribution towards an understanding of electrophysiological and molecular phenotypic responses to external stimuli in the Afh model. Moreover, as DNA methylation has recently emerged as a new regulator of neuronal networks with important consequences for circadian behaviour, we discuss the impact of the Afh mutation on the epigenetic landscape of circadian biology.

scholarly journals Coactivator PC4 Mediates AP-2 Transcriptional Activity and Suppresses ras-Induced Transformation Dependent on AP-2 Transcriptional Interference

1999 ◽  
Vol 19 (1) ◽  
pp. 899-908 ◽  
Author(s):  
Perry Kannan ◽  
Michael A. Tainsky
Keyword(s):  
Gene Expression ◽  
Growth Rate ◽  
Transcription Factors ◽  
Cell Lines ◽  
Transcriptional Activity ◽  
Suppressive Effect ◽  
Transcriptional Coactivator ◽  
Transcriptional Interference ◽  
Mechanism Of Inhibition ◽  
Teratocarcinoma Cells

ABSTRACT ras oncogene-transformed PA-1 human teratocarcinoma cells have abundant AP-2 mRNA but, paradoxically, little AP-2 transcriptional activity. We have previously shown that overexpression of AP-2 in nontumorigenic variants of PA-1 cells results in inhibition of AP-2 activity and induction of tumorigenicity similar to that caused by ras transformation of PA-1 cells. Evidence indicated the existence of a novel mechanism of inhibition of AP-2 activity involving sequestering of transcriptional coactivators. In this study, we found that PC4 is a positive coactivator of AP-2 and can restore AP-2 activity in ras-transformed PA-1 cells. Relative to vector-transfected ras cell lines,ras cell lines stably transfected with and expressing the PC4 cDNA have a diminished growth rate and exhibit a loss of anchorage-independent growth, and they are unable to induce the formation of tumors in nude mice. These data suggest that a transcriptional coactivator, like a tumor suppressor, can have a growth-suppressive effect on cells. Our experiments are the first to show that ras oncogenes and oncogenic transcription factors can induce transformation through effects on the transcription machinery rather than through specific programs of gene expression.

Heme oxygenase-1 induction by hemin prevents oxidative stress-induced acute cholestasis in the rat

2019 ◽  
Vol 133 (1) ◽  
pp. 117-134 ◽  
Author(s):  
Pamela L. Martín ◽  
Paula Ceccatto ◽  
María V. Razori ◽  
Daniel E.A. Francés ◽  
Sandra M.M. Arriaga ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heme Oxygenase ◽  
Bile Flow ◽  
Driving Forces ◽  
Membrane Lipids ◽  
Ex Vivo ◽  
Heme Oxygenase 1 ◽  
Canalicular Transporters

Abstract We previously demonstrated in in vitro and ex vivo models that physiological concentrations of unconjugated bilirubin (BR) prevent oxidative stress (OS)-induced hepatocanalicular dysfunction and cholestasis. Here, we aimed to ascertain, in the whole rat, whether a similar cholestatic OS injury can be counteracted by heme oxygenase-1 (HO-1) induction that consequently elevates endogenous BR levels. This was achieved through the administration of hemin, an inducer of HO-1, the rate-limiting step in BR generation. We found that BR peaked between 6 and 8 h after hemin administration. During this time period, HO-1 induction fully prevented the pro-oxidant tert-butylhydroperoxide (tBuOOH)-induced drop in bile flow, and in the biliary excretion of bile salts and glutathione, the two main driving forces of bile flow; this was associated with preservation of the membrane localization of their respective canalicular transporters, bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2), which are otherwise endocytosed by OS. HO-1 induction counteracted the oxidation of intracellular proteins and membrane lipids induced by tBuOOH, and fully prevented the increase in the oxidized-to-total glutathione (GSHt) ratio, a sensitive parameter of hepatocellular OS. Compensatory elevations of the activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) were also prevented. We conclude that in vivo HO-1 induction protects the liver from acute oxidative injury, thus preventing consequent cholestasis. This reveals an important role for the induction of HO-1 and the consequently elevated levels of BR in preserving biliary secretory function under OS conditions, thus representing a novel therapeutic tool to limit the cholestatic injury that bears an oxidative background.

scholarly journals α-MSH Counteracts the Suppressive Effect of Ultraviolet B on Nrf1/2 and Nrf-Dependent Gene Expression in Human Skin

2009 ◽  
Vol 94 (5) ◽  
pp. 1835-1835
Author(s):  
Agatha Kokot ◽  
Dieter Metze ◽  
Nicolas Mouchet ◽  
Marie-Dominique Galibert ◽  
Meinhard Schiller ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Skin ◽  
Suppressive Effect ◽  
Ultraviolet B

scholarly journals Comparing the Effects of the mTOR Inhibitors Azithromycin and Rapamycin on In Vitro Expanded Regulatory T Cells

2019 ◽  
Vol 28 (12) ◽  
pp. 1603-1613 ◽  
Author(s):  
Marcus Bergström ◽  
Malin Müller ◽  
Marie Karlsson ◽  
Hanne Scholz ◽  
Nils Tore Vethe ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Ex Vivo ◽  
Mtor Inhibitors ◽  
Allogeneic Transplantation ◽  
Suppressive Effect ◽  
And Function ◽  
Treg Phenotype ◽  
Suppression Assay

Adoptive transfer of autologous polyclonal regulatory T cells (Tregs) is a promising option for reducing graft rejection in allogeneic transplantation. To gain therapeutic levels of Tregs there is a need to expand obtained cells ex vivo, usually in the presence of the mTOR inhibitor Rapamycin due to its ability to suppress proliferation of non-Treg T cells, thus promoting a purer Treg yield. Azithromycin is a bacteriostatic macrolide with mTOR inhibitory activity that has been shown to exert immunomodulatory effects on several types of immune cells. In this study we investigated the effects of Azithromycin, compared with Rapamycin, on Treg phenotype, growth, and function when expanding bulk, naïve, and memory Tregs. Furthermore, the intracellular concentration of Rapamycin in CD4+ T cells as well as in the culture medium was measured for up to 48 h after supplemented. Treg phenotype was assessed by flow cytometry and Treg function was measured as inhibition of responder T-cell expansion in a suppression assay. The concentration of Rapamycin was quantified with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Azithromycin and Rapamycin both promoted a FoxP3-positive Treg phenotype in bulk Tregs, while Rapamycin also increased FoxP3 and FoxP3+Helios positivity in naïve and memory Tregs. Furthermore, Rapamycin inhibited the expansion of naïve Tregs, but also increased their suppressive effect. Rapamycin was quickly degraded in 37°C medium, yet was retained intracellularly. While both compounds may benefit expansion of FoxP3+ Tregs in vitro, further studies elucidating the effects of Azithromycin treatment on Tregs are needed to determine its potential use.

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