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PubMed1993

Lectin staining of the endothelial cell membrane is more sensitive to ultraviolet radiation than the epidermal cell staining in guinea-pig skin.

Ultraviolet radiation (UVR)-induced alterations in lectin stainings of both endothelial and epidermal cells were histochemically analysed in guinea-pig skin using Bandeiraea simplicifolia agglutinin-I and Ricinus communis agglutinin-I. The endothelial cell staining with both lectins was more sensitive to a single exposure to middle-wave UVR (UVB) and topical psoralen plus long-wave UVR (UVA) (PUVA) than the epidermal cell staining. More remarkable changes were seen following PUVA radiation than UVB radiation. No significant alterations were induced by UVA radiation alone or psoralen alone. The results suggest that the endothelial cell is a susceptible target for UVB and PUVA radiation.

Animals↗
PubMed1993

Degradation of psoralen photo-oxidation products induced by ferrous ions.

Psoralen was irradiated at 366 nm in aerated aqueous or ethanol solutions. Fe2+ ions reduced photo-oxidized psoralen (POP) with the formation of free radicals and electronically excited states. Free radicals were detected by the electron spin resonance (ESR) method using the spin trap C-phenyl-N-tert-butyl-nitrone (PBN), and electronically excited states were registered by chemiluminescence (ChL) accompanying the destruction of POP by Fe2+ ions. PBN could not scavenge directly free radicals generated by the reduction of POP with Fe2+ and required the presence of ethanol during the reaction. Analysis of ESR spectra indicated that PBN trapped hydroxyethyl free radicals which were produced as a byproduct in the reaction of POP and Fe2+. The dependence of the yield of PBN adducts on the fluence of psoralen irradiation and the concentration of Fe2+ ions was measured. Although both ESR and ChL estimated the POP products destructible by Fe2+ (POPFe), they gave information about different POPFe products. A kinetic analysis showed that ChL-estimated POPFe products were produced with the participation of two molecules of psoralen (one in the electronically excited state and one in the ground state), whereas ESR-estimated POPFe products were produced with the participation of one molecule of psoralen in the excited state. ESR-estimated products were stable in both water and ethanol solutions and could be stored for 20 h without significant decay; pre-incubation of POP solutions with catalase or glutathione-peroxidase decreased the yield of PBN adducts by 50%. ChL-estimated products were essentially less stable, about 30% being spontaneously destroyed during storage in ethanol solution at room temperature; pre-incubation of these products with catalase decreased the ChL by 90%. The possible biological role of POPFe products is discussed.

Electron Spin Resonance Spectroscopy↗
PubMed2004

Cinnamic acid 4-hydroxylase mechanism-based inactivation by psoralen derivatives: cloning and characterization of a C4H from a psoralen producing plant-Ruta graveolens-exhibiting low sensitivity to psoralen inactivation.

Cinnamate 4-hydroxylase (C4H, EC 1.14.13.11) complete cDNA was cloned from the leaves of Ruta graveolens, a psoralen producing plant. The recombinant enzyme (classified CYP73A32) was expressed in Saccharomyces cerevisiae. Mechanism-based inactivation was investigated using various psoralen derivatives. Only psoralen and 8-methoxypsoralen were found to inactivate C4H. The inactivation was dependent on the presence of NADPH, time of pre-incubation, and inhibitor concentration. Inactivation stoichiometry was 0.9 (+/-0.2) for CYP73A1 and 1.1 (+/-0.2) for CYP73A32. SDS-PAGE analysis demonstrated that [3H]psoralen was irreversibly bound to the C4H apoprotein. K(i) and k(inact) for psoralen and 8-methoxypsoralen inactivation on the two C4H revealed a lower sensitivity for CYP73A32 compared to CYP73A1. Inactivation kinetics were also determined for CYP73A10, a C4H from another furocoumarin-producing plant, Petroselinum crispum. This enzyme was found to behave like CYP73A32, with a weak sensitivity to psoralen and 8-MOP inactivation. Cinnamic acid hydroxylation is a key step in the biosynthesis of phenylpropanoid compounds, psoralen derivatives included. Our results suggest a possible evolution of R. graveolens and P. crispum C4H that might tolerate substantial levels of psoralen derivatives in the cytoplasmic compartment without a depletive effect on C4H and the general phenylpropanoid metabolism.

Amino Acid Sequence↗
PubMed2004

Synthesis and photocytotoxic activity of new alpha-methylene-gamma-butyrolactone-psoralen heterodimers.

The synthesis of a new alpha-methylene-gamma-butyrolactone-psoralen heterodimer 2 is reported. Its photoantiproliferative activity and skin phototoxicity were compared with that of 5-methoxypsoralen (5-MOP) and another heterodimer 1. Both derivatives show a significant phototoxicity toward malignant cell lines including melanoma cells A375 compared to their intrinsic cytotoxicity in the dark. Both compounds were found to be nonphototoxic on mice skin and therefore could be active potential drugs in photochemotherapy.

Animals↗
PubMed2004

An efficient new method for extraction, separation and purification of psoralen and isopsoralen from Fructus Psoraleae by supercritical fluid extraction and high-speed counter-current chromatography.

Psoralen and isopsoralen were extracted from Fructus Psoraleae (Psoralea corylitolia L.) by supercritical CO2. The effect of various parameters, i.e., pressure, temperature and sample particle size on yield was investigated with an analytical-scale supercritical fluid extraction (SFE) system to find the optimal conditions. The process was then scaled up by 50 times with a preparative SFE system under the optimized conditions of pressure (26 MPa), temperature (60 degrees C) and a sample particle size of 40-60 mesh. The yield of the preparative SFE was 9.1% and the combined yield of psoralen and isopsoralen was 2.5 mg/g of dry seeds. Psoralen and isopsoralen in the extract were separated and purified by high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:0.7:1:0.8, v/v), and the fractions were analyzed by HPLC, MS, 1HNMR and 13C NMR. The structures of the products were further confirmed by comparison with authentic samples (National Institute of the Control of Pharmaceutical and Biological Products, Beijing, China).

Chromatography, High Pressure Liquid↗
PubMed2004

Preparative isolation and purification of psoralen and isopsoralen from Psoralea corylifolia by high-speed counter-current chromatography.

Psoralen and isopsoralen were separated from Psoralea corylifolia by high-speed counter-current chromatography (HSCCC). A two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (5:5:4.5:5.5, v/v) was used for HSCCC separation, and yielded, from 100 mg of crude extract, 39.6 mg of psoralen and 50.8 mg of isopsoralen each at over 99% purity as determined by high performance liquid chromatography (HPLC). The identification of psoralen and isopsoralen were performed with 1H NMR and 13C NMR.

Chromatography, High Pressure Liquid↗
PubMed2005

The yeast rDNA locus: a model system to study DNA repair in chromatin.

Most of the studies on the effect of chromatin structure and chromatin remodeling on DNA repair are based on in vitro reconstituted assays. In such experiments individual nucleosomes are either released by nuclease digestion of native chromatin fibers or are assembled from purified histones. Though reconstituted assays are valid approaches to follow NER in chromatin they are of somehow limited physiological relevance since single core particles do not exist in vivo [K. van Holde, J. Zlatanova, The nucleosome core particle: does it have structural and physiological relevance? Bioessays 21 (1999) 776-778]. This is particularly true for studies involving core histones tails, as in their natural chromatin context histones tails participate in interactions that are not necessarily present in vitro [J.C. Hansen, C. Tse, A.P. Wolffe, Structure and function of the core histone N-termini: more than meets the eye, Biochemistry 37 (1998) 17637-17641; J.J. Hayes, J.C. Hansen, Nucleosomes and chromatin fiber, Curr. Opin. Genet. Dev. 11 (2001) 124-129]. Indeed it was found that human DNA ligase I has the capability to ligate a nick on the surface of a 215bp nucleosome but not a nick in a nucleosome lacking linker DNA, possibly because of forced interactions between histone tails and core DNA present in the latter complex [D.R. Chafin, J.M. Vitolo, L.A. Henricksen, B.A. Bambara, J.J. Hayes, Human DNA ligase I efficiently seals nicks in nucleosomes, EMBO J. 19 (2000) 5492-5501]. In addition, chromatin remodeling could also occur in the higher ordered folding of chromatin and involve multiple arrays of nucleosomes [P.J. Horn, C.L. Peterson, Chromatin higher order folding: wrapping up transcription, Science 297 (2002) 1824-1827]. By studying the chromatin structure of ribosomal genes in yeast, our knowledge of the fate of nucleosomes during transcription and DNA replication has improved considerably [R. Lucchini, J.M. Sogo, The dynamic structure of ribosomal RNA gene chromatin, in: M.R. Paule (Ed.), Transcription of Ribosomal RNA Genes by Eukaryotic RNA Polymerase I, Springer-Verlag/R.G. Landes Company, 1998, pp. 254-276]. How nuclear processes such as DNA repair take place in chromatin is still largely unknown, and in this review I discuss how the yeast rDNA locus may be exploited to investigate DNA repair and chromatin modification in vivo.

Chromatin↗
PubMed2005

Psoralen-sensitive mutant pso9-1 of Saccharomyces cerevisiae contains a mutant allele of the DNA damage checkpoint gene MEC3.

Complementation analysis of the pso9-1 yeast mutant strain sensitive to photoactivated mono- and bifunctional psoralens, UV-light 254 nm, and nitrosoguanidine, with pso1 to pso8 mutants, confirmed that it contains a novel pso mutation. Molecular cloning via the reverse genetics complementation approach using a yeast genomic library suggested pso9-1 to be a mutant allele of the DNA damage checkpoint control gene MEC3. Non-complementation of several sensitivity phenotypes in pso9-1/mec3Delta diploids confirmed allelism. The pso9-1 mutant allele contains a -1 frameshift mutation (deletion of one A) at nucleotide position 802 (802delA), resulting in nine different amino acid residues from that point and a premature termination. This mutation affected the binding properties of Pso9-1p, abolishing its interactions with both Rad17p and Ddc1p. Further interaction assays employing mec3 constructions lacking the last 25 and 75 amino acid carboxyl termini were also not able to maintain stable interactions. Moreover, the pso9-1 mutant strain could no longer sense DNA damage since it continued in the cell cycle after 8-MOP + UVA treatment. Taken together, these observations allowed us to propose a model for checkpoint activation generated by photo-induced adducts.

Alleles↗
PubMed2006

gamma-H2AX formation in response to interstrand crosslinks requires XPF in human cells.

To further define the molecular mechanisms involved in processing interstrand crosslinks, we monitored the formation of phosphorylated histone H2AX (gamma-H2AX), which is generated in chromatin near double strand break sites, following DNA damage in normal and repair-deficient human cells. Following treatment with a psoralen derivative and ultraviolet A radiation doses that produce significant numbers of crosslinks, gamma-H2AX levels in nucleotide excision repair-deficient XP-A fibroblasts (XP12RO-SV) increased to levels that were twice those observed in normal control GM637 fibroblasts. A partial XPA revertant cell line (XP129) that is proficient in crosslink removal, exhibited reduced gamma-H2AX levels that were intermediate between those of GM637 and XP-A cells. XP-F fibroblasts (XP2YO-SV and XP3YO) that are also repair-deficient exhibited gamma-H2AX levels below even control fibroblasts following treatment with psoralen and ultraviolet A radiation. Similarly, another crosslinking agent, mitomycin C, did not induce gamma-H2AX in XP-F cells, although it did induce equivalent levels of gamma-H2AX in XPA and control GM637 cells. Ectopic expression of XPF in XP-F fibroblasts restored gamma-H2AX induction following treatment with crosslinking agents. Angelicin, a furocoumarin which forms only monoadducts and not crosslinks following ultraviolet A radiation, as well as ultraviolet C radiation, resulted only in weak induction of gamma-H2AX in all cells, suggesting that the double strand breaks observed with psoralen and ultraviolet A treatment result preferentially following crosslink formation. These results indicate that XPF is required to form gamma-H2AX and likely double strand breaks in response to interstrand crosslinks in human cells. Furthermore, XPA may be important to allow psoralen interstrand crosslinks to be processed without forming a double strand break intermediate.

Cell Line↗
PubMed2006

Nuclear targeting of non-viral gene carriers using psoralen-nuclear localization signal (NLS) conjugates.

A nuclear localization signal was non-covalently attached to DNA for the purpose of enhancing transfection efficiencies of non-viral gene carriers. Psoralen, a nucleic acid-intercalating agent, was chemically attached to a signal peptide. The conjugate spontaneously intercalated into DNA and then poly(ethyleneimine) [PEI] was added to prepare a DNA/PEI complex containing the signal peptide moieties. The existence of the conjugate did not alter the complexation process between DNA and PEI, which was confirmed by dynamic light scattering. The conjugate was slowly released from the DNA/PEI complex for 24h, while a burst release was examined when the conjugated was added to DNA without PEI. The complex containing a signal peptide moiety increased transfection efficiencies on COS-1 cells, compared to a mutant signal peptide or a control. Cytotoxicity of the conjugate slowly increased as the amount of the conjugate increased, however, the cytotoxic effect of the conjugate was not significant at the effective concentration of the conjugate for transfections. Therefore, the psoralen-nuclear localization signal is expected to be a potent transfection enhancing agent without a covalent modification of transgenes.

Amino Acid Sequence↗
PubMed2004

Activation of gene expression by triplex-directed psoralen crosslinks.

Psoralen-conjugated triplex-forming oligonucleotides (pso-TFOs) can target photochemical adducts to specific DNA sequences. Here, we have used pso-TFOs to activate gene expression on a plasmid. We designed a pso-TFO adapter, consisting of a single-stranded TFO for targeting DNA, linked to a double-stranded hairpin segment that contains a hybrid ecdysone response element (E/GRE) enhancer for binding activated ecdysone receptors. When targeted to the 5' flanking region of a minimal promoter, this pso-TFO adapter increased the expression of a downstream reporter gene three- to four-fold. Gene activation, however, was independent of both the E/GRE hairpin of the adapter and ecdysone receptors, suggesting it was due to an intrinsic effect of triplex. Gene activation was dependent on psoralen photo-crosslinking. Gene activation by pso-TFOs in which the psoralen was linked to the TFO via a disulfide bond was similar before and after detachment of the TFO and its release from the triplex. These results indicate that psoralen photo-crosslinks play a prominent role in activation. Gene activation was undiminished in XPA, XPD and XPG human cell lines, indicating that activation was not dependent on the complete nucleotide excision repair (NER) pathway. Collectively, these results demonstrate that TFOs can be used to direct psoralen crosslinks adjacent to a gene as a way of activating gene expression.

Binding Sites↗
PubMed2005

Traditional systemic treatments have not fully met the needs of psoriasis patients: results from a national survey.

BACKGROUND: Many psoriasis patients are dissatisfied with current therapies. However, patient-centered levels of satisfaction with individual treatments have not been well described. OBJECTIVE: To assess patients' satisfaction with 4 systemic treatment options available before 2002. METHODS: We used data from a recent national survey. Psoriasis patients were randomly recruited from the general US population, members of the Psoriasis Foundation, and persons who contacted the Psoriasis Foundation but did not join. The interview included questions about use and satisfaction with specific Psoriasis therapy. RESULTS: Of 1197 psoriasis patients interviewed, 311 (26%) indicated current or past use of methotrexate, psoralen plus ultaviolet A (PUVA), cyclosporin, and/or acitretin (users). Compared with those who had never used any of these systemic therapies, users reported more extensive disease (adjusted odds ratio [OR] = 2.90, 95% confidence interval [CI] = 1.87-4.49) and higher Psoriasis Disability Index scores (category V: adjusted OR = 2.31, 95% CI = 1.22-4.36). After adjusting for these variables, more than one third of patients were dissatisfied with each therapy, except for PUVA (14%). Patients were most satisfied with methotrexate and PUVA. However, less than 40% of the users indicated they were very satisfied with any of the 4 therapies assessed. Only 10% of persons who ever used cyclosporin were currently using it. In a paired analysis, cyclosporin users were significantly less satisfied with cyclosporin than with other therapies ( P = .01). CONCLUSION: For most patients, none of the 4 systemic therapies widely utilized in 2002 for psoriasis were highly satisfactory. If we are to learn whether new treatments satisfy patients' needs, long term, prospective, comparative studies of heterogeneous patient populations that include patients' assessments are needed.

Acitretin↗
PubMed2006

Alopecia areata: a long term follow-up study of 191 patients.

BACKGROUND: The prognosis of alopecia areata (AA) is difficult to predict. Few studies report long-term follow-up of AA patients. OBJECTIVE: The purpose of this study is to better assess the long-term evolution of AA and the possible relationship between disease severity and treatment response with long-term prognosis. METHODS: One hundred ninety-one patients with AA who presented with a new diagnosis of AA between 1983 and 1990 were subsequently contacted by phone. Patients were queried regarding current disease status, treatments, and disease course. RESULTS: Severity of AA at first consultation ranged from mild (128 patients) to severe (63 patients). Fifty-five of 191 patients were affected by concomitant autoimmune or related inflammatory disease. Sixty-six of 191 patients were presently disease free (follow-up duration, 15-22 years; mean 17.74 years). These include 41 of 60 patients with S1 disease (68.3%), 22 of 68 patients with S2 disease (32.3%), 1 of 11 patients with S3 disease (9%), 1 of 14 patients with S4 disease (7.1%), and 1 of 11 patients with alopecia totalis (AT) (9.1%). Sixty-nine of 191 patients (36-1%) were presently affected by AT or alopecia universalis. There was a statistically significant tendency of severe patterns of AA to worsen over time. In children, 18 of 39 (13 with < or =S2 disease and 5 with > or =S3 disease) with AA had developed AT or alopecia universalis at long-term follow-up. In children, however, this trend was not statistically significant. Patients with severe AA who responded to topical immunotherapy seem to have a better prognosis than nonresponders. LIMITATIONS: Follow-up was only performed by phone. CONCLUSIONS: Severity of AA at time of first consultation is an important prognostic factor. Response to therapy (topical immunotherapy) may be associated with better prognosis. In children, the prognosis is worse; our study found that AA worsens over time.

Administration, Topical↗
PubMed2005

Fingerprint analysis of Psoralea corylifolia L. by HPLC and LC-MS.

High-performance liquid chromatography (HPLC) was developed for fingerprint analysis of Psoralea corylifolia. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MSn) technique was first employed to identify the components of the fingerprint. The samples were separated with an Alltima C18 column (250 mm x 4.6 mm, 5 microm) by linear gradient elution using water-acetic acid (A; 100:0.1, v/v) and acetonitrile (B; 0 min, 40%; 15 min, 50%; 35 min, 60%; 45 min, 70%; 55 min, 80%; and maintained for 5 min) as mobile phase at a flow rate of 1.0 ml/min and detector wavelength at 245 nm. A standard procedure was developed for HPLC fingerprint analysis. Average chromatogram of 10 batches of P. corylifolia L. from Sichuan and Henan Provinces, PR China, which has been considered as the original and genuine herbal medicine for a long time, was first established as the characteristic fingerprint. There are 12 common peaks in this fingerprint. Ten of these common peaks were identified by MS data. This profile was then used to identify and assess the differences among the herb grown in various areas of China. The HPLC fingerprint analysis is specific and may serve for quality identification and comprehensive evaluation of P. corylifolia.

Benzofurans↗