Quantitation of interferon gamma mRNA levels in psoralen/UVA-treated HUT-78 cells by competitive PCR

Effect of glucose on the expression of type I collagen and transforming growth factor-beta1 in cultured human peritoneal fibroblasts

OBJECTIVE

To determine the effect of high glucose levels on the expression of type I collagen, and whether this effect is regulated by transforming growth factor (TGF)-beta1 in human peritoneal fibroblasts in culture.

DESIGN

Prospective experimental study.

SETTING

University medical center.

PATIENT(S)

Primary cultures of fibroblasts established from peritoneal tissues of five patients. High glucose treatment of the primary cultured fibroblasts.

MAIN OUTCOME MEASURE(S)

Primary cultures of human peritoneal fibroblasts were incubated with varying amounts of glucose (1-5 g/L) for 24 hours. Total RNA was extracted from human peritoneal fibroblasts and converted to cDNA by reverse transcriptase. Multiplex reverse transcriptase/polymerase chain reaction (PCR) simultaneously co-amplifying beta-actin with TGF-beta1 or type I collagen mRNAs was used to quantitate type I collagen and TGF-beta1 mRNA levels in response to increasing glucose concentrations with and without TGF-beta1 antibody treatment.

RESULT(S)

There was a significant increase in the mRNA for type I collagen and TGF-beta1 in response to increasing glucose concentrations in a dose response-dependent manner. The TGF-beta1 antibody treatment resulted in an 83% and 68% decrease in type I collagen and TGF-beta1 mRNA levels, respectively.

CONCLUSION(S)

Increasing glucose concentrations stimulated type I collagen expression in human peritoneal fibroblasts in culture. A potential mediator for this effect is TGF-beta1. These results have implications not only for individuals with diabetes mellitus who may be predisposed to greater postoperative adhesion development, but also for individuals with surgical stress responses after surgery.

Augmentation of monocyte interleukin-8 production by psoralen/UVA-treated CD4+ T cells

Treatment of cells with psoralen and ultraviolet A light (UVA) modulates their cytokine production. As extracorporeal photochemotherapy has been reported to induce cytokine production by monocytes, we quantified interleukin-8 (IL-8), a representative chemokine produced by monocytes, in culture supernatants from human peripheral blood mononuclear cells (PBMC) treated with 8-methoxypsoralen (8-MOP) and UVA. Lipopolysaccharide stimulated IL-8 production in 8-MOP-phototreated PBMC more efficiently than those untreated or treated with 8-MOP or UVA. More interestingly, when cultured with T-cell-stimulating anti-CD3 and anti-CD28 antibodies, 8-MOP/UVA-treated PBMC produced enhanced amounts of IL-8 with an increased level of IL-8 mRNA expression. Depletion of CD4 but not CD8 T cells from PBMC abrogated this augmented IL-8 elaboration, and CD4 T cells per se secreted no substantial amount of IL-8 even upon CD3/CD28 stimulation. Thus, 8-MOP/UVA-treated CD4 T cells stimulated monocytes to secrete IL-8. The IL-8 overproduction was induced by direct contact of monocytes with 8-MOP/UVA-treated CD4 T cells but not by cytokines from the treated CD4 T cells. These findings imply that in extracorporeal photochemotherapy, monocytes effectively produce IL-8 by cell-to-cell contact with 8-MOP/UVA-treated malignant CD4 T cells. The augmentation of monocyte cytokine/chemokine production by 8-MOP/UVA may be one of the mechanisms underlying the therapeutic efficacy of extracorporeal photochemotherapy.

Photoactivational cytokine-modulatory action of 8-methoxypsoralen plus ultraviolet A in lymphocytes, monocytes, and cutaneous T cell lymphoma cells

Treatment with 8-methoxypsoralen (8-MOP) and ultraviolet A light (UVA) has been reported to modulate cytokine production in various cells. Our study was conducted to see the effects of 8-MOP/UVA on the expression/production of cytokines in peripheral blood lymphocytes and monocytes in relation to the therapeutic mechanisms of extracorporeal photochemotherapy. 8-MOP/UVA augmented the expression of mRNAs for interferon-gamma (IFN-gamma) and interleukin (IL)-2 and reduced those for IL-4 and IL-10 in peripheral blood mononuclear cells (PBMCs) from normal subjects and Sézary syndrome patients. This enhancement of Th1 cytokines was caused by increment of cytokine production by Th1 cells but not by conversion of Th2 cells to produce Th1 cytokines. The number of IFN-gamma-secreting lymphocytes was markedly increased in 8-MOP/UVA-treated PBMCs 20 h after treatment, and its amount was elevated in culture supernatants. However, this enhanced production of IFN-gamma was found only until three days after 8-MOP phototreatment, and its level was rapidly declined by five days after treatment. In addition to this Th1-polarized action, 8-MOP/UVA-treated PBMCs produced enhanced amounts of IL-8 upon stimulation with anti-CD3/CD28 antibodies. Phototreated CD4+ but not CD8+ cells provided excellent T cell help for monocytes to produce IL-8 via a direct cell-to-cell contact mechanism. These findings suggest that 8-MOP/UVA has a transient but biologically active Th1-skewing action in T cells, and the phototreated T cells simultaneously stimulate monocytes to produce IL-8. It is suggested that 8-MOP/UVA exerts a beneficial therapeutic effect on malignant Th2 neoplasms as a Th1-skewing cytokine modifier and that 8-MOP-phototreated CD4+ T cells allow monocytes to become effective tumor antigen-presenting cells for tumor-specific cytotoxic T cells.

Treatment of peripheral blood mononuclear cells with 8-methoxypsoralen plus ultraviolet A radiation induces a shift in cytokine expression from a Th1 to a Th2 response

Treatment with 8-methoxypsoralen plus ultraviolet A radiation and extracorporeal photochemotherapy (photopheresis) are widely used for the treatment of psoriasis and other inflammatory skin diseases, graft-versus-host disease, and mycosis fungoides. As the ratio of Th1 and Th2 cells appears to be critical for pathogenesis and progression of these disorders the effect of psoralen plus ultraviolet A on Th1 and Th2 cytokine production by CD4+ lymphocytes was investigated. Human peripheral blood lymphocytes were incubated in the presence of anti-CD3, rh-IL2, and rh-IL4 for 48 h. After subsequent stimulation with rh-IL2 and rh-IL4 for 72 h cells were treated with 8-methoxypsoralen (100, 500, 1000 ng per ml) plus ultraviolet A (2 J per cm2) and incubated for a further period of 5 h in the presence of ionomycine, phorbol-12-myristate acetate and monensin. Fluorescence-activated cell sorter analysis revealed a significant reduction of interleukin-2- and interferon-gamma-producing CD4+ cells upon psoralen plus ultraviolet A treatment depending on the concentration of 8-methoxypsoralen. In contrast, interleukin-4-producing CD4+ cells were increased, indicating a shift from Th1 to a Th2 cell cytokine profile upon psoralen plus ultraviolet A treatment. These results indicate that 8-methoxypsoralen photochemotherapy of lymphocytes is able to modulate their Th1/Th2 distribution. Inhibition of Th1 cytokine expression by psoralen plus ultraviolet A might help to explain its beneficial effects in the treatment of Th1 dominated skin diseases.

Alteration of type I and III collagen expression in human peritoneal mesothelial cells in response to hypoxia and transforming growth factor-beta1

Overexpression and accumulation of extracellular matrix is central to peritoneal adhesion formation following surgically induced tissue trauma. Transforming growth factor-beta1 and hypoxia have been implicated in tissue fibrosis and postoperative adhesion formation. To extend this observation we examined whether transforming growth factor-beta1 and/or hypoxia regulate the expression of type I and III collagen in human peritoneal mesothelial cells. Cultured human mesothelial cells were maintained under hypoxia (2% oxygen), or treated with transforming growth factor-beta1 (1 ng/ml) or a combination of hypoxia and transforming growth factor-beta1. Total cellular RNA from treated and untreated cells were collected and subjected to multiplex reverse transcription/polymerase chain reaction to quantitate collagen I and III mRNA levels in response to these treatments. The results indicate that 6 hours of hypoxia increased collagen III mRNA by 7.2 fold which was further increased to 9.4 fold following transforming growth factor-beta1 treatment; in contrast collagen I mRNA decreased by 0.42 fold which was further decreased by 0.3 fold following transforming growth factor-beta1 treatment. Transforming growth factor-beta1 treatment under normal conditions resulted in an 8.4-fold increase and a 0.3-fold decrease in collagen III and I mRNA levels, respectively. Hypoxia treatment also resulted in a 1.9-fold increase in transforming growth factor-beta1 mRNA level compared with control. The ratio of type III/I collagen was increased in response to transforming growth factor-beta1 treatment under hypoxic condition. In conclusion, the data suggest that hypoxia may modulate extracellular matrix production by human mesothelial cells via a transforming growth factor-beta1 dependent mechanism.

Treatment of T lymphocytes with 8-methoxypsoralen plus ultraviolet A induces transient but biologically active Th1-skewing cytokine production

8-Methoxypsoralen plus ultraviolet A light is suggested to shift T lymphocytes from Th2 to Th1 cells. To clarify this issue, we examined the effects of 8-methoxypsoralen/ultraviolet A on the expression/production of cytokines in peripheral blood mononuclear cells from normal subjects and a Sézary syndrome patient. 8-Methoxypsoralen/ultraviolet A augmented the expression of mRNAs for interferon-gamma and interleukin-2 and reduced those for interleukin-4 and interleukin-10. It seems that this enhancement of Th1 cytokines is caused by increment of cytokine production by Th1 cells but not by conversion of Th2 cells to produce Th1 cytokines. The number of interferon-gamma-secreting lymphocytes was markedly increased in 8-methoxypsoralen/ultraviolet A-treated peripheral blood mononuclear cells 20 h after treatment, whereas that of Th2 cytokine-producing cells was decreased. Accordingly, the amount of interferon-gamma was elevated in culture supernatants from 8-methoxypsoralen-phototreated peripheral blood mononuclear cells, whereas interleukin-4 was significantly reduced. This enhanced production of interferon-gamma, however, was found only until 3 d after 8-methoxypsoralen phototreatment and was declined by 5 d after treatment. Finally, 8-methoxypsoralen/ultraviolet A treatment of T cells regulated their ability to induce keratinocyte CD54 expression. Our results show that 8-methoxypsoralen/ultraviolet A has a transient but biologically active Th1-skewing action in human T cells, suggesting that 8-methoxypsoralen/ultraviolet A exerts a beneficial therapeutic effect on Th2-mediated or Th2-malignant diseases.

Modulation of cytokine production by 8-methoxypsoralen and UVA

Modulatory effects on cytokine expression of 8-MOP in conjunction with UVA have been investigated in different systems using different cell types, including keratinocytes, lymphocytes, monocytes and endothelial cells. The vast majority of data have exhibited reduced production of cytokines in 8-MOP/UVA-treated cells and skin, reflecting its simplistic cellular damage. However, 8-MOP/UVA at modest doses stimulate T lymphocytes to produce Thl cytokines such as interferon-gamma, suggesting that some activational events may occur in certain types of cells phototreated with 8-MOP. Both the inhibitory and augmentative effects of 8-MOP/UVA on cytokine production appear to participate in the mechanisms underlying the therapeutic efficacy of PUVA and extracorporeal photochemotherapy (photopheresis). In particular, photopheresis may exert beneficial effects on cutaneous T-cell lymphoma as a cytokine modifier.

Psoralen photobiology and photochemotherapy: 50 years of science and medicine

In 1998 it is appropriate to commemorate the 50th anniversary of el Mofty's use of purified 8-methoxypsoralen (8-MOP) in the treatment of vitiligo (el Mofty AM. A preliminary clinical report on the treatment of leukoderma with Ammi majus linn. J R Egypt Med Assn 1948,31:651 65. el Mofty AM, el Sawalhy H, el Mofty M. Clinical study of a new preparation of 8-methoxypsoralen in photochemotherapy. Int J Dermatol 1994;8:588 92). Two young American dermatologists (Aaron Lerner and Thomas Fitzpatrick) were intrigued by the potency of this material. After Lerner determined that artificial long wavelength ultraviolet (320-400 nm, UVA) radiation was the most efficient for activating 8-MOP. the development of artificial sources enabled the efficient delivery of these photons to skin containing 8-MOP. Their initial studies for vitiligo led to further development of this therapy for the treatment of psoriasis (Parrish JA, Fitzpatrick TB, Tannenbaum L, et al. Photochemotherapy of psoriasis with oral methoxsalen and long-wave ultraviolet light. New Engl J Med 1974;291:1207-11. Honigsmann H, Fitzpatrick TB, Pathak MA, et al. Oral photochemotherapy with psoralen and UVA (PUVA): principles and practice. In: Fitzpatrick TB, Eisen AZ, Wolf K, editors. Dermatology in General Medicine. New York: McGraw-Hill, 1987:1728-54). This photochemotherapy came to be called 'PUVA' (psoralen + UVA). The position PUVA holds today as one of the most common procedures performed in dermatology can be traced to their initial curiosity and their subsequent ingenuity. Further developments in more recent years capitalized on their seminal work. The therapy met with unprecedented success from the outset, leaving little perceived need to understand underlying science. However, in recent years there has been a new found interest in the basic aspects of psoralen photobiology and molecular mechanistic events contributing to therapeutic responses as well as to the development of skin cancers in PUVA patients. These will be surveyed in this review commemorating the 50 years of modern psoralen photobiology and photomedicine.

Clinical and mechanistic aspects of photopheresis

Photopheresis is an extracorporeal form of photochemotherapy with 8-methoxypsoralen (8-MOP) and ultraviolet A (UVA) radiation. Photopheresis is used for the management of T-cell-mediated diseases, and such treatment leads to the induction of antigen-specific immune suppression directed to the pathogenic clone of T cells. Photopheresis is used to treat a wide variety of diseases--such as cutaneous T-cell lymphoma, systemic sclerosis; rheumatoid arthritis, lupus erythematosus--and is also successfully applied in the suppression of graft rejection. In addition to the clinical achievements, attention will be paid to results from animal studies. An important outcome of these studies is that photopheresis can be used to treat airway hyperreactivity. Furthermore, it was shown that the therapeutic strategy can be changed drastically: the presence of plasma during irradiation should be avoided and the amount of blood that must be treated to obtain the desired antigen-specific immunosuppression can be greatly decreased. Also, results from cellular experiments are discussed. An example of this is the increase in the major histocompatibility complex expression on the surface of cells found after treatment. The mechanism that underlies photopheresis has not yet been elucidated, but progress has been made. The following related points will be reviewed: models for investigation; and mechanistic aspects, with the emphasis on cellular biomacromolecules and on photosensitizers (drugs) other than 8-MOP.

T-cell cytokine network in cutaneous lupus erythematosus

BACKGROUND

A variety of immunologic abnormalities have been described in systemic and experimental lupus erythematosus (LE). Several T-cell defects, especially in helper T (Th) cell cytokines, have been reported.

OBJECTIVE

Our purpose was to identify the Th cytokine profile in cutaneous LE.

METHOD

Total RNA was extracted from punch biopsy specimens from 19 patients with cutaneous LE (nine, discoid LE; two, subacute cutaneous LE; and eight, systemic LE) and from four healthy control subjects. RNA was reverse transcribed into complementary DNA and amplified with polymerase chain reaction (PCR) primers specific for interleukin-2 (IL-2), IL-4, IL-5, IL-10, interferon gamma (IFN-gamma), and beta actin. PCR products were detected by agarose gel electrophoresis and Southern blot with 32P-labeled, nested probes.

RESULTS

Sixteen of 19 cutaneous LE specimens lacked IL-2, all were negative for IL-4, and 10 of 19 had detectable IL-10, whereas IFN-gamma and IL-5 messenger RNAs were present in the majority of LE specimens. IFN-gamma and IL-10 mRNAs were found in all normal skin controls, whereas IL-2, IL-4, and IL-5 mRNAs were undetectable. Functional IFN-gamma protein was evidenced by intercellular adhesion molecule-1 and HLA-DR staining of keratinocytes in nine of nine LE specimens but not in normal skin. The pattern of cytokine mRNAs, intercellular adhesion molecule-1, and/or HLA-DR expression in cutaneous LE specimens did not vary with different subtypes of LE, antinuclear antibody titer, or the magnitude of inflammation.

CONCLUSION

The presence of IL-5 mRNA in cutaneous LE specimens suggests that Th type 2 cells combine with local IFN-gamma production to augment disease and may be related to the pathophysiology of cutaneous LE.

Quantification of interleukin-6 mRNA in wallerian degeneration by competitive reverse transcription polymerase chain reaction

Following peripheral nerve injury, cytokines might be critically involved in regulating the cellular response within the lesioned nerve but are frequently difficult to measure due to their low abundancy. Competitive quantitative RT-PCR assays are potentially useful in quantifying cytokine mRNAs in small tissue samples but frequently do not fulfill the theoretical demands on proportional amplification of natural and standard sequences. Using this technique, we constructed standard curves for rat interleukin (IL)-6 mRNA with strictly proportional slopes and shifts when varying natural and standard RNA concentrations. A strong and transient increase in IL-6 mRNA was found in both nerve stumps 12 h after rat sciatic nerve transection, with low expression already in uninjured rat sciatic nerves. IL-6 might be involved in regulating the cellular response to peripheral nerve injury, and standard curves obtained by independent variation of standard and natural RNA are helpful in detecting and controlling experimental variables and pitfalls in competitive RT-PCR assays, thus increasing their reliability and reproducibility.

The immunological effect of 8-methoxypsoralen and UVA treatment on murine T-cell leukemia

8-Methoxypsoralen (8-MOP) plus long-wavelength UV radiation (UVA, 320-400 nm) have been used to treat various diseases such as cutaneous T-cell lymphoma, systemic scleroderma, rheumatoid arthritis and rejection of heart transplants. However, the immunological mechanism of this treatment remains unknown. In this report, we investigated the effect of 8-MOP/UVA on the modulation of the immunogenicity of a T-cell leukemia cell line (RL male 1 cells). The results demonstrated that the stimulator function of the in vitro 8-MOP/UVA-treated RL male 1 cells was enhanced in both RL male 1-specific allogeneic and syngeneic immune responses. Furthermore, the enhancement of the immunogenicity of the 8-MOP/UVA-treated RL male 1 cells was found to be strongly associated with the increase of intercellular adhesion molecule-1 expression on these 8-MOP/UVA-treated tumor cells. Therefore, our findings suggested that the alteration of the expression of the immune-related cell surface molecules might be an important effect of 8-MOP/UVA treatment on the elevation of the immunogenicity of the 8-MOP/UVA-treated tumor cells.

Treatment with 8-MOP and UVA enhances MHC class I synthesis in RMA cells: preliminary results

The response of psoriasis and cutaneous T-cell lymphoma to treatment with 8-methoxypsoralen (8-MOP) and long wavelength ultraviolet light (UVA) is only partly understood. Psoralens form photoadducts within the DNA after activation by UVA and this damage leads to the inhibition of DNA synthesis. Additionally, it has been shown that different forms of DNA damage can induce a stress response, leading to upregulation of selected products. Among these are the major histocompatibility complex (MHC) class I genes. Thus the aim of the present study was to assess the rate of synthesis of MHC class I proteins in murine T-cell lymphoma cells (RMA) after treatment with 8-MOP and UVA. RMA cells were treated with 8-MOP (50-200 ng ml-1) and UVA (1 J.cm-2) and metabolically labelled with 35S-methionine 4 and 24 h after treatment. MHC class I synthesis was determined by immunoprecipitation of the cell lysates with an anti-Kb monoclonal antibody, Y3. After 4 h, treated and untreated cells demonstrated no differences in the rate of MHC class I synthesis. However, after 24 h a dose-dependent increase in MHC class I synthesis was observed. This increase in MHC class I expression could be responsible, at least partly, for the responses observed in patients treated with photopheresis.