The role of Nrf2 in the antioxidant cellular response to medical ozone exposure

Ozone (O3) is a natural, highly unstable atmospheric gas that rapidly decomposes to oxygen. Although not being a radical molecule, O3 is a very strong oxidant and therefore it is potentially toxic for living organisms. However, scientific evidence proved that the effects of O3 exposure are dose-dependent: high dosages stimulate severe oxidative stress resulting in inflammatory response and tissue injury, whereas low O3 concentrations induce a moderate oxidative eustress activating antioxidant pathways. These properties make O3 a powerful medical tool, which can be used as either a disinfectant or an adjuvant agent in the therapy of numerous diseases. In this paper, the cellular mechanisms involved in the antioxidant response to O3 exposure will be reviewed with special reference to the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its role in the efficacy of ozone therapy

Ozone at low concentrations does not affect motility and proliferation of cancer cells in vitro

Exposure to low ozone concentrations is used in medicine as an adjuvant/complementary treatment for a variety of diseases. The therapeutic potential of low ozone concentrations relies on their capability to increase the nuclear translocation of the Nuclear factor erythroid 2-related factor 2 (Nrf2), thus inducing the transcription of Antioxidant Response Elements (ARE)-driven genes and, through a cascade of events, a general cytoprotective response. However, based on the controversial role of Nrf2 in cancer initiation, progression and resistance to therapies, possible negative effects of ozone therapy may be hypothesised in oncological patients. With the aim to elucidate the possible changes in morphology, migration capability and proliferation of cancer cells following mild ozone exposure, we performed wound healing experiments in vitro on HeLa cells treated with low ozone concentrations currently used in the clinical practice. By combining a multimodal microscopy approach (light and fluorescence microscopy, scanning electron microscopy, atomic force microscopy) with morphometric analyses, we demonstrated that, under our experimental conditions, exposure to low ozone concentrations does not alter cytomorphology, motility and proliferation features, thus supporting the notion that ozone therapy should not positively affect tumour cell growth and metastasis

Ozone activates the Nrf2 pathway and improves preservation of explanted adipose tissue in vitro

In clinical practice, administration of low ozone (O3) dosages is a complementary therapy for many diseases, due to the capability of O3 to elicit an antioxidant response through the Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2)-dependent pathway. Nrf2 is also involved in the adipogenic differentiation of mesenchymal stem cells, and low O3 concentrations have been shown to stimulate lipid accumulation in human adipose-derived adult stem cells in vitro. Thus, O3 treatment is a promising procedure to improve the survival of explanted adipose tissue, whose reabsorption after fat grafting is a major problem in regenerative medicine. In this context, we carried out a pilot study to explore the potential of mild O3 treatment in preserving explanted murine adipose tissue in vitro. Scanning and transmission electron microscopy, Western blot, real-time polymerase chain reaction and nuclear magnetic resonance spectroscopy were used. Exposure to low O3 concentrations down in the degradation of the explanted adipose tissue and induced a concomitant increase in the protein abundance of Nrf2 and in the expression of its target gene Hmox1. These findings provide a promising background for further studies aimed at the clinical application of O3 as an adjuvant treatment to improve fat engraftment

Environmental awareness gained during a citizen science project in touristic resorts is maintained after 3 years since participation

The research leading to these results has received funding from Project AWARE Foundation, ASTOI Association, Milano, Ministry of Tourism of the Arab Republic of Egypt, Settemari S. p. A Tour Operator, Scuba Nitrox Safety International, Viaggio nel Blu Diving Center.Tourism is one of the largest economic sectors in the world. It has a positive effect on the economy of many countries, but it can also lead to negative impacts on local ecosystems. Informal environmental education through Citizen Science (CS) projects can be effective in increasing citizen environmental knowledge and awareness in the short-term. A change of awareness could bring to a behavioral change in the long-term, making tourism more sustainable. However, the long-term effects of participating in CS projects are still unknown. This is the first follow-up study concerning the effects of participating in a CS project on cognitive and psychological aspects at the basis of pro-environmental behavior. An environmental education program was developed, between 2012 and 2013, in a resort in Marsa Alam, Egypt. The study directly evaluated, through paper questionnaires, the short-term (after 1 week or 10 days) retention of knowledge and awareness of volunteers that had participated in the activities proposed by the program. After three years, participants were re-contacted via email to fill in the same questionnaire as in the short-term study, plus a new section with psychological variables. 40.5% of the re-contacted participants completed the follow-up questionnaires with a final sample size of fifty-five people for this study. Notwithstanding the limited sample size, positive trends in volunteer awareness, personal satisfaction regarding the CS project, and motivation to engage in pro-environmental behavior in the long-term were observed.Publisher PDFPeer reviewe

Low ozone concentrations promote adipogenesis in human adipose-derived adult stem cells

Ozone is a strong oxidant, highly unstable atmospheric gas. Its medical use at low concentrations has been progressively increasing as an alternative/adjuvant treatment for several diseases. In this study, we investigated the effects of mild ozonisation on human adipose-derived adult stem (hADAS) cells i.e., mesenchymal stem cells occurring in the stromal-vascular fraction of the fat tissue and involved in the tissue regeneration processes. hADAS cells were induced to differentiate into the adipoblastic lineage, and the effect of low ozone concentrations on the adipogenic process was studied by combining histochemical, morphometric and ultrastructural analyses. Our results demonstrate that ozone treatment promotes lipid accumulation in hADAS without inducing deleterious effects, thus paving the way to future studies aimed at elucidating the effect of mild ozonisation on adipose tissue for tissue regeneration and engineering

Effects of mild ozonisation on the dynamics of lipid droplets in adipose-derived stem cells and mature adipocytes

The effects of mild ozonisation on the dynamics of lipid droplets in adipose cells are describe

Effects of mild ozonisation on the dynamics of lipid droplets in adipose-derived stem cells and mature adipocytes

The effects of mild ozonisation on the dynamics of lipid droplets in adipose cells are describe

Adipogenic effect of mild ozonisation on human adipose-derived adult stem cells

Effects of low ozone concentrations on human adipose-derived adult stem (hADAS) cells by combining light and electron microscop

Mild ozonisation induces lipid accomulation in human adipose-derived adult stem cells

The effects of mild ozonisation on human adipose-derived adult stem (hADAS) cells was investigated combining light and transmission electron microscop

Ozone treatment induces antioxidant stress response through Keap1/Nrf2 dependent pathway

Recently ozone therapy has been applied successfully as adjuvant therapy in the treatment of several disorders such as rheumatoid arthr\u131tis, heart and vascular disease, asthma emphysema and multiple sclerosis. Positive effects of ozone therapy have been hypothesized to rely on the capability of mild acute oxidative stress to induce antioxidant response. Nevertheless, molecular mechanisms behind those beneficial effects remain unclear. Some evidence suggests that mild oxidative stress induced by ozone treatments leads to activation of the transcription factor Nrf2 (nuclear factor erythroid-derived-like2). Nrf2 regulates the expression of genes under the control of antioxidant response element (ARE) enhancer. These genes include drug metabolizing enzymes, such as glutathione s-transferases (GSTs) and NAD(P)H-quinone Oxidoreductase 1 (NQO1), and antioxidant genes, such as heme oxygenase-1 (OH-1), the subunit of \u3b3-glutamylcysteine synthetase (\u3b3-GCS) and thioredoxin. Under basal conditions, Nrf2 is sequestered in the cytoplasm by its specific inhibitor Keap1 (Kelch-like ECH associated protein), which promotes Nrf2 ubiquitination and proteasomal degradation within a few minutes after its transcription. Under specific stimuli, Nrf2 dissociates from Keap1 and is preserved from degradation. Then, Nrf2 translocates into the nucleus, heterodimerizes with Maf proteins and trans-activates ARE-mediated genes. The current study was designed to investigate whether ozone therapy might induce ARE activation via Nrf2-dependent mechanisms. First, we established a HeLa cell line engineered to express NanoLuc Luciferase under the control of ARE promoter. We show that the treatment with different concentrations of ozone increased ARE-driven expression of NanoLuc in a dose- 413 dependent manner (Figure 1a). Ultrastructural immunocytochemistry showed Nrf2 to be associated to perichromatin fibrils, which are sites of active transcription (Figure 1b). Hela cells were transiently transfected with Nrf2-GFP and/or Keap1-dsRed fusion proteins to enable microscopy visualization of Nfr2 and Keap1 subcellular localization (Figure 2a). As expected, in untreated cells Nrf2-GFP disappeared when co-transfected with Keap1-dsRed. In contrast, ozone treatment induced persistence of Nrf2-GFP fluorescence and its massive nuclear translocation, suggesting that ozone might prevent Keap1-mediated Nrf2 degradation. In line with this conclusion we found an increased amount of Nrf2 protein compared to controls over 30 minutes after ozone treatment (Figure 2b), likely due to an increased Nrf2 stability. Finally, Keap1 transient overexpression partially reverted ARE-Luc activation in ozone treated cells (Figure 2c), thus providing further evidence that ozone treatment is able to induce an antioxidant stress response through a Keap1/Nrf2-dependent pathway