Evaluation of UVA-Mediated Oxidative Damage to Proteins and Lipids in Extracorporeal Photoimmunotherapy

Hepatoprotective effects of hydroxysafflor yellow A in D-galactose-treated aging mice

Hydroxysafflor yellow A (HSYA) is an effective chemical component isolated from Chinese herb Carthamus tinctorius L. In present study, we aimed to evaluate the effects of HSYA on D-galactose- (D-gal-) induced aging in mice, and to elucidate the underlying mechanism. Male C57BL/6 mice were intraperitoneal injection of D-gal and HSYA for 8 weeks. The body weight gain, spleen and thymus coefficients were determined. Levels of super dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) in serum and liver were measured using commercial kits. Pathological changes and the SA-β-Gal activity in liver tissues were detected by hematoxylin and eosin and SA-β-Gal staining. The expression levels of p16, CDK4, CDK6 and phosphorylation levels of Retinoblastoma (Rb) were detected by immunohistochemistry and western blot analysis. mRNA levels of genes regulated by p16-Rb pathway were determined by quantitative real-time PCR. In vivo, HSYA improved the aging changes including body weight, organ index and antioxidant status such as activities of SOD, CAT, GSH-Px and MDA in D-gal treated aging mice. HSYA also dramatically attenuated pathologic changes of aging liver tissues induced by D-gal. Furthermore, HSYA significantly decreased the mRNA and protein level of cyclin-dependent kinase inhibitor p16, followed by increasing CDK4/6 protein expression and decreasing the phosphorylation of Retinoblastoma (pRb) which up-regulated the expression of downstream genes CCNE1, CCNA2, P107 and MCM4. Collectively, these data indicated that HSYA could ameliorate aging, especially hepatic replicative senescence resulting from D-gal, the mechanism could be associated with the suppression of p16-Rb pathway.

Ultraviolet radiation and echinoderms: past, present and future perspectives

There is general consensus that solar ultraviolet radiation (UVR) negatively impacts many marine species. Echinoderms are ubiquitous within the marine environment, with members of the phyla often long-lived and numerically dominant within the benthic macrofauna, consequently the impact of UVR on the population dynamics of these organisms will influence marine communities and ecosystems. Research to date has shown that exposure of echinoderms to solar UVR can, affect reproduction and development, change behaviour, cause numerous biochemical and physiological changes and potentially cause increased mutation rates, by causing DNA damage. There is also considerable evidence that echinoderms utilise several different mechanisms to protect themselves against excessive UVR and subsequent UVR-induced damage. However, these protective mechanisms may pose conflicting selection pressures on echinoderms, as UVR is an additional stressor in oceans subjected to anthropogenic-induced climate change. This review summarises our knowledge of the effects of UVR on the Echinodermata. We outline the research conducted to date, highlight key studies on UVR that have utilised echinoderms and look to the future of UVR research in a rapidly changing ocean.

UVA1 radiation (340–400nm) interferes with the perforin-granule system of CD8hi+ cytotoxic T lymphocytes in vitro

UVA1-irradiation was introduced as an innovative and effective phototherapy of atopic dermatitis (AD) and other skin diseases. In AD, a defect of a central apoptosis inducing effector system involved in immunoregulation and immune defense, i.e., the system of perforin-granules in cytotoxic T lymphocytes (CTL), was recently reported: perforin-reduction and perforin-hyperreleasability. We now investigated UVA1-effects on the perforin-granule system in vitro. Peripheral blood CTLs were exposed in vitro to 10-100 J/cm2 UVA1 (340-400 nm), and to 30-150 mJ/cm2 UVB (280-315 nm) as a control. A time-dependent perforin-granule release was induced by phorbol 12-myristate 13-acetate (PMA) and ionomycin. This release was inhibited dose-dependently by UVA1, but not by UVB. An UVA1-dose dependent pattern of sensitive (80%) and insensitive (20%) individuals was found. The kinetics of perforin release in AD-CTLs, i.e. hyperreleasability, was normalized by 50 J/cm2 UVA1 in vitro. Sodium azide as a quencher of reactive oxygen species prevented the UVA1-mediated inhibition of perforin-granule release. Our data demonstrate for the first time a dose- and wavelength-dependent UVA1-effect in vitro on a major effector system of cytotoxic lymphocytes, the system of perforin-granules. This might contribute to the further understanding of immunomodulatory UVA1-effects in vivo.

Multiple Involvement of Oxidative Stress in Werner Syndrome Phenotype

Werner syndrome is a genetic disease characterized by early ageing, excess cancer risk, high incidence of type II diabetes mellitus, early atherosclerosis, ocular cataracts, and osteoporosis. The protein encoded by the defective gene, WRN (WRNp) associates with three activities, that is, a RecQ DNA helicase, 3'-5'-exonuclease and ATPase activities. By highlighting the DNA helicase activity, a widespread consensus in WS-associated defect(s) has been established, pointing toward a deficiency in maintaining DNA integrity. However, a possible involvement of redox pathways in WS may be suggested by several lines of evidence that include: (i) the multiple functions and interactions of WRNp with oxidative stress-related activities and factors; (ii) the pleiotropic WS clinical phenotype encompassing a number of oxidative stress-related pathologies; (iii) redox-related toxicity mechanisms of several xenobiotics exerting excess toxicity in WS cells; (iv) recent in vivo and in vitro findings of redox abnormalities in WS patients and in WS cells. The working hypothesis is raised that a deficiency in WRNp, and the pleiotropic clinical phenotype in WS patients may provide the basis to envision an underlying in vivo prooxidant state, which causes oxidative damage to biomolecules, with multiple oxidative stress-related alterations, resulting in multi-faceted clinical consequences.

Quantitative echographic analysis of photochemotherapy on systemic sclerosis skin

Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology, in which development of fibrosis, vascular insufficiency and inflammatory processes are prominent in the skin as well as in other organs. We studied the effect of photochemotherapy with quantitative echography in SSc. Dermal echo intensity and dermal thickness was measured using high-frequency dermal echography before and after therapy. The dermal echo intensity after photochemotherapy (33.51+/-9.34) significantly increased than that before therapy (21.23+/-6.00) (P < 0.01), while dermal thickness (1.20+/-0.20) significantly decreased than that before therapy (1.38+/-0.18) (P < 0.05). Photochemotherapy was more likely to improve dermal edema, not fibrosis, because echo intensity after treatment was significantly elevated with that before treatment in patients with edema. Quantitative echographic analysis was concluded to be a reliable method in evaluating the change of skin edema in SSc.

Phototoxicity, distribution and kinetics of association of UVA-activated chlorpromazine, 8-methoxypsoralen, and 4,6,4′-trimethylangelicin in Jurkat cells

Extracorporeal phototherapy (ECP) is a therapeutic approach based on photobiological effects of 8-methoxypsoralen (8-MOP) on white blood cells isolated from the blood, exposed to UVA and then reinfused into the patient. 8-MOP is presently the only drug approved for clinical application of ECP; therefore, identification of other photosensitizers with better photochemical and pharmacokinetic properties might enhance the efficacy of this treatment modality. Among such alternative drugs are 4,6,4'-trimethylangelicin (TMA) and chlorpromazine (CPZ), which have previously been studied in an animal model for ECP. In this current study, cellular bioavailability of 8-MOP, TMA and CPZ was investigated in vitro, using low doses of UVA relevant for the clinical setting of ECP. Our fluorescence microscopy study revealed that 8-MOP and CPZ penetrated readily into the cells, where they accumulated with similar kinetics. No distinct fluorescence was observed in cells incubated with TMA. We found that the phototoxic efficiency of 8-MOP was an order of magnitude greater than that of CPZ, i.e., to obtain a similar reduction in survival of cells subjected to photosensitization by the drugs, the concentration of CPZ needed to be 10 times higher than that of 8-MOP. The photoactivated TMA exhibited the highest pro-apoptotic efficiency. A clear indication of photoinduced formation of reactive oxygen species and peroxidation of lipids was observed only in CPZ-sensitized cells, suggesting different mechanisms for phototoxicity mediated by CPZ and by the two furocoumarins.

Fanconi anaemia proteins: major roles in cell protection against oxidative damage

Fanconi anaemia (FA) is a cancer-prone genetic disorder that is characterised by cytogenetic instability and redox abnormalities. Although rare subtypes of FA (B, D1 and D2) have been implicated in DNA repair through links with BRCA1 and BRCA2, such a role has yet to be demonstrated for gene products of the common subtypes. Instead, these products have been strongly implicated in xenobiotic metabolism and redox homeostasis through interactions of FANCC with cytochrome P-450 reductase and with glutathione S-transferase, and of FANCG with cytochrome P-450 2E1, as well as redox-dependent signalling through an interaction between FANCA and Akt kinase. We hypothesise that FA proteins act directly (via FANCC and FANCG) and indirectly (via FANCA, BRCA2 and FANCD2) with the machinery of cellular defence to modulate oxidative stress. The latter interactions may co-ordinate the link between the response to DNA damage and oxidative stress parameters (3, 6-12).

The expression of matrix metalloproteinase-1 mRNA induced by ultraviolet A1 (340-400 nm) is phototherapy relevant to the glutathione (GSH) content in skin fibroblasts of systemic sclerosis

The excessive deposition of collagen in systemic sclerosis (SSc) is thought to be due to an abnormal function of fibroblasts, which may be the result of an immune dysregulation in skin. Ultraviolet A1 (UVA1) irradiation has been shown to be an effective therapy. This is thought to be due to its capacity to induce matrix metalloproteinase-1 (MMP-1) expression in human dermal fibroblasts. In the present in vitro study, the effect of UVA1 irradiation on MMP-1 was studied using skin fibroblasts from healthy controls (n=5) and patients with systemic sclerosis (n=5). In vitro irradiation studies showed that gene expression for MMP-1 after UVA1 irradiation (p<0.05) was induced in all the fibroblasts studied, but that the induction rate was greater in SSc fibroblasts than in normal ones (p<0.05). The glutathione (GSH) level was lower in SSc fibroblasts than in controls before UVA1 irradiation. However, after UVA1 irradiation, GSH levels were increased and equivalent between normal and SSc fibroblasts. These findings indicated that the relatively stronger increase in MMP-1 expression in SSc fibroblasts was due to the lower antioxidant capacity. These data support the concept that clinical responses to UVA1 radiation are influenced by the antioxidative state of the patients' skin.

Capillary zone electrophoresis with electrochemical detection--a simple and effective method to analyze oxygen-consuming and peroxide-forming processes

Numerous biological, chemical and photochemical processes consume molecular oxygen, thereby forming peroxides, hydroperoxides and even hydrogen peroxide. This paper describes a new system for monitoring quasi simultaneously oxygen uptake and peroxide formation. For this purpose capillary electrophoresis with electrochemical detection was connected to a new automated injector that periodically injects a sample of the reaction mixture into the capillary electrophoresis system without any contact with the atmosphere. The device was tested with some pharmacologically relevant reactions such as enzymatic oxidation of glucose catalyzed by glucose oxidase, enzymatic lipid oxidation by lipoxygenase and the photodynamic reaction of the anti-inflammatory drug ketoprofen.

A sensitive gas chromatography-mass spectrometry assay reveals increased levels of monohydroxyeicosatetraenoic acid isomers in human plasma after extracorporeal photoimmunotherapy and under in vitro ultraviolet A exposure

Extracorporeal photoimmunotherapy (photopheresis) is a highly effective therapy in the treatment of various disorders. Although extracorporeal photoimmunotherapy has been successfully used for more than 10 y, its mechanism of action is still unclear. The formation of reactive oxygen species have been implicated in extracorporeal photoimmunotherapy, but malonyl dialdehyde as a marker of systemic lipid peroxidation did not increase significantly during treatment. To investigate further the involvement of reactive oxygen species in extracorporeal photoimmunotherapy, we have introduced a highly sensitive negative ion gas chromatography-mass spectrometry based method for quantitating oxygenated arachidonic acid isomers (hydroxyeicosatetraenoic acids) in plasma samples of patients treated with extracorporeal photoimmunotherapy. In the plasma of healthy volunteers pmole amounts of 2-, 3-, 5-, 8-12-, and 15-hydroxyeicosatetraenoic acid were detected and we observed a dose-dependent augmentation in these metabolites when the blood was irradiated with increasing doses of ultraviolet A in the presence of the photosensitizer 8-methoxypsoralen. Analysis of plasma samples obtained from patients before and after extracorporeal photoimmunotherapy revealed a characteristic increase in total hydroxyeicosatetraenoic acid levels, particularly of 5-hydroxyeicosatetraenoic acid which contributed 80% to the sum of all hydroxyeicosatetraenoic acid isomers. Chiral phase high-performance liquid chromatography indicated almost equal amounts of 5S- and 5R-hydroxyeicosatetraenoic acid suggesting that the majority of lipid peroxidation products are formed via nonenzymatic oxidation reactions.

PUVA (psoralen + UVA) photochemotherapy: processes triggered in the cells

Photochemotherapy using psoralens and UVA is a treatment used widely in some skin diseases, in cutaneous lymphomas and in autoimmune diseases. This review has selected recent publications dealing with the photochemical processes triggered in the cells by UVA radiation and psoralen treatment. The photochemical changes initiated in the cell membranes were described.