Resveratrol protects SR-B1 levels in keratinocytes exposed to cigarette smoke

Cigarette smoking (CS) has been strongly linked to several health conditions including heart disease, lung cancer, and other respiratory and circulatory ailments. Deleterious effects of cigarette smoking on skin have also been well documented, but unlike effects on other organs, damage does not depend upon inhalation. The upper layer of the skin, the stratum corneum (rich in cholesterol fatty acids and ceramide), is very susceptible to damage induced by exposure to environmental stressors that can modify its lipid composition and thereby affect its function of protecting skin from dehydration. Scavenger receptor B1 (SR-B1) is involved in the uptake of cholesterol in several tissues including skin. We previously demonstrated that CS exposure induces formation of aldehyde (HNE) adducts that decrease SR-B1 expression. As topical resveratrol, a well-known polyphenolic stilbene, has been demonstrated to show benefits against skin disorders, we investigated its possible role as a protective agent against CS-induced reduction of SR-B1 expression in cutaneous tissue. In this study, we demonstrate that resveratrol at doses ranging from 0.5 to 10 μM is not toxic and is able to increase SR-B1 protein levels in a dose-dependent manner in human keratinocytes. Moreover, when the cells that were pretreated with various doses of resveratrol were exposed to CS, the loss of SR-B1 was prevented in a dose-dependent manner. In addition, in keratinocytes, resveratrol was also able to prevent an increase in HNE-protein adducts induced by CS. In particular resveratrol was able to prevent HNE-SR-B1 adduct formation. Thus, resveratrol seems to be a natural compound that could provide skin with a defense against exogenous stressors by protecting the essential cholesterol receptor, SR-B1.

Ozonated oils as functional dermatological matrices: effects on the wound healing process using SKH1 mice

Wound tissue repair is a complex and dynamic process of restoring cellular structures and tissue layers. Improvement of this process is crucial for several pathologies characterized by chronic delayed wound closure such as diabetes, and the investigation of new approaches aimed to ameliorate the wound healing process is under continuous evolution. Recently, the usage of vegetable matrices in the form of ozonated oils has been proposed and several researchers have shown a positive effect in the wound, based on their bactericidal, antiviral, and antifungal properties. The present study was undertaken to compare the effect that different ozonated oils (olive, sesame and linseed) with the same level of ozonation have on wound healing rate in SKH1 mice. Several histological parameters and the level of key proteins such as VEGF and PCNA have been analyzed. Only treatment with ozonated sesame oil shows a faster wound closure in the first 7 days. This effect paralleled with the increased VEGF and PCNA levels, NFκB nuclear translocation and 4-HNE formation. The present study shows that not only the ozonation grade is of importance for the improvement of wound healing process but also the typical composition of the oil.

Preparation and characterization of carbon-titania nanocomposite-supported Pd3Co alloy nanoparticles for oxygen reduction

A TiO2-modified carbon (C-TiO2) has been employed as a catalyst support of Pd3Co alloy for electroduction of oxygen. Due to the strong interaction between highly dispersed TiO2 and Pd3Co alloy, the C-TiO2 support was shown to be effective for a fine dispersion of Pd3Co alloys. The degree of sintering of Pd3Co on C-TiO2 could largely decrease during heat-treatment for reduction compared to that on unmodified carbon support (C). In oxygen reduction reaction (ORR), the reduced catalysts (Pd3Co/C-X and Pd3Co/C-TiO2-X; X represents reduction temperature) showed higher catalytic performance than their as-prepared catalysts. The catalytic activities of Pd3Co/C-TiO2-X were largely enhanced compared to those of Pd3Co/C-X. The ORR activity was measured to be the highest on Pd3Co/C-TiO2-300, which was 9 times enhanced activity (at 0.85 V) relative to the best-performed catalyst supported on carbon (Pd3Co/C-400). A positive role of TiO2 for the metal dispersion, the retardation of metal growth during heat-treatment, and the modification of electronic structure of Pd3Co was responsible for the enhanced ORR performance on Pd3Co/C-TiO2-X.

Autophagy deficiency in beta cells leads to compromised unfolded protein response and progression from obesity to diabetes in mice

AIMS/HYPOTHESIS

The unfolded protein response (UPR) in endoplasmic reticulum (ER) and autophagy are known to be related. We investigated the role of autophagy in UPR of pancreatic beta cells and the susceptibility of autophagy-deficient beta cells to the ER stress that is implicated in the development of diabetes.

METHODS

Rat insulin promoter (RIP)-Cre(+);autophagy-related 7 (Atg7)(F/W) mice were bred with ob/w mice to derive RIP-Cre(+);Atg7(F/F)-ob/ob mice and to induce ER stress in vivo. GFP-LC3(+)-ob/ob mice were generated to examine in vivo autophagic activity. Real-time RT-PCR was performed to study the expression of the genes of the UPR machinery. Proteolysis was assessed by determining release of incorporated radioactive leucine.

RESULTS

Production of UPR machinery was reduced in autophagy-deficient beta cells, which was associated with diminished production of p85α and p85β regulatory subunits of phosphoinositide 3-kinase. Because of compromised UPR machinery, autophagy-deficient beta cells were susceptible to ER stressors in vitro. When mice with beta cell-specific autophagy deficiency, which have mild hyperglycaemia, were bred with ob/ob mice to induce ER stress in vivo, severe diabetes developed, which was accompanied by an increase in beta cell death and accumulation of reactive oxygen species. The increased demand for UPR present in obesity was unmet in autophagy-deficient beta cells. Autophagy level and autophagic activity were enhanced by lipid, while proteolysis was reduced.

CONCLUSIONS/INTERPRETATION

These results suggest that autophagy is important for intact UPR machinery and appropriate UPR in response to lipid injury that increases demand for UPR. Autophagy deficiency in pancreatic beta cells may contribute to the progression from obesity to diabetes.