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CELLULAR AND MOLECULAR
Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan (N.B., K.C.N., M.R., J.V.); Department of Dermatology, University of Michigan Medical School, and Dermatology Service, and Veterans Affairs Medical Center, Ann Arbor, Michigan (C.N.E.); Department of Medicinal Chemistry, University of Mississippi, Oxford, Mississippi (A.C., M.A.); Departments of Family Medicine, Kern Medical Center and University of California, Irvine, California (H.A.P.); Bethesda Pharmaceuticals, Inc., Bakersfield, California (H.A.P.); and Department of Laboratory Medicine, University of California, San Francisco, California (T.W.K.)
Received for publication
June 15, 2005
Accepted
August 17, 2005.
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Abstract |
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can ameliorate clinical features of psoriasis in humans. Thiazolidinediones also inhibit the proliferation of psoriatic keratinocytes in monolayer and organ culture, and at least one of these agents (troglitazone) inhibits epidermal hyperplasia of human psoriatic skin transplanted to severe-combined immunodeficient (SCID) mice. In the present study, we show that a novel, synthetic, thiazoladinedione derivative, BP-1107 ({2-[4-(2,4-dioxo-thiazolidin-5-ylmethyl)-phenoxy]-ethyl}-methyl-amide), is capable of inhibiting psoriatic hyperplasia in the SCID mouse transplant model after topical application. Like other thiazolidinediones, BP-1107 inhibits proliferation of rapidly growing keratinocytes in monolayer culture, but compared with these agents, the effective dose of BP-1107 needed to suppress keratinocyte proliferation is much lower. Concentrations of BP-1107 that effectively inhibit keratinocyte function have no detrimental effect on dermal fibroblasts. These data suggest that effective topical antipsoriatic therapy may be provided with this agent.
, interferon-, and various interleukins (IL-2, IL-6, and IL-8) (Nickoloff, 1991
; Valdimarsson et al., 1995; Austin et al., 1999). Although the immune system is likely to be responsible for initiating the disease, the subsequent hyperproliferative response in the keratinocytes seems to be a direct consequence of proproliferative intraepidermal events.
In recent studies, we (Ellis et al., 2000; Bhagavathula et al., 2004) and other investigators (Komuves et al., 1998; Kubota et al., 1998; Mueller et al., 1998; Rivier et al., 1998, 2000; Sarraf et al., 1998; Mao-Qiang et al., 2004) have shown that agonists of the peroxisome proliferator-activated receptor- (PPAR-), including thiazolidinediones such as troglitazone, rosiglitazone, and pioglitazone, reduce epithelial cell proliferation and induce differentiation. At least one of the thiazolidinediones (i.e., troglitazone) normalizes the histological appearance of human psoriatic skin in organ culture and in the human skin-severe-combined immunodeficient (SCID) mouse model (Ellis et al., 2000). Both troglitazone and pioglitazone have been shown to reduce the clinical and histological presentation of psoriasis after systemic treatment (Pershadsingh et al., 1998; Ellis et al., 2000; Robertshaw and Friedmann, 2005; Shafiq et al., 2005). Unfortunately, these agents cause serious side effects (fluid retention and weight gain) in a subset of patients. Although the first clinically approved thiazolidinedione ligand of PPAR- (troglitazone) was withdrawn from the market because of hepatotoxicity, this does not seem to be a class effect because liver toxicity has not been an issue with other PPAR- activators such as pioglitazone or rosiglitazone (Lebovitz, 2002).
Recently, we synthesized a series of thiazolidinedione PPAR- agonists. One of these agents (referred to as BP-1107) was shown to have high affinity for PPAR- (EC50 of 26 pM compared with 64 nM for rosiglitazone) (Bhagavathula et al., 2004). Given the high affinity of BP-1107 for PPAR-, we conducted a series of experiments to assess the ability of this agent to modulate keratinocyte proliferation in vitro and epidermal thickness in the human skin-SCID mouse transplant model. Our results show that BP-1107 is a potent keratinocyte growth inhibitor in vitro and effectively reduces epidermal hyperplasia of human psoriatic skin transplanted to SCID mice. Of significance, BP-1107 is effective when delivered topically.
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Materials and Methods |
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ligand, was obtained from Dr. Avery (Department of Medicinal Chemistry, University of Mississippi, Oxford, MS) and Bethesda Pharmaceuticals, Inc. (Bakersfield, CA). Structurally, BP-1107 is an adamantyl-coupled thiazolidinedione (Fig. 1).
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-tubulin was obtained from Santa Cruz Biotechnology, Inc. (Santa Cruz, CA). Epidermal growth factor (EGF) was from R&D Systems (Minneapolis, MN). Human Tissue. Six-millimeter punch biopsies of psoriatic lesional skin (four biopsies per volunteer) were obtained from two individuals with active psoriasis on the trunk and/or hip. Neither of the tissue donors was on therapy at the time of biopsy, and neither had been on systemic therapy for a period of at least 6 months. Six-millimeter punch biopsies of skin were also obtained from four nonpsoriatic volunteers (four biopsies per volunteer). The use of human skin in this study was approved by the University of Michigan Institutional Review Board, and biopsies were obtained after receiving written informed consent from the donors.
Transplantation Procedure. SCID mice (CB-17 strain; Taconic Farms, Germantown, NY) were used as tissue recipients. One 6-mm punch biopsy was transplanted onto the dorsal surface of a recipient mouse as described previously (Zeigler et al., 2001). In brief, mice were anesthetized, and skin from the dorsal region was shaved. Mouse skin was surgically removed to size and replaced with the human tissue. The human tissue was secured to the back of the mouse with absorbable sutures (4-0 Dexon"S"; Davis-Geck, Manati, Puerto Rico). The transplants were then bandaged with Xeroform petrolatum dressing (Kendall Company, Mansfield, MA) for 3 to 4 days. The animals were maintained in a pathogen-free environment throughout the preparation and treatment phases. Treatment was initiated 1 to 2 weeks post-transplantation, depending on how rapidly the tissue healed. The human skin-SCID mouse transplant model has been used previously to study the pathophysiology of psoriasis (Nickoloff et al., 1995; Wrone-Smith and Nickoloff, 1996; Gilhar et al., 1997) and to assess potential antipsoriatic therapies (Ellis et al., 2000; Zeigler et al., 2001; Bhagavathula et al., 2005).
In Vivo Treatment Protocol. Normal human skin and psoriatic lesional plaque skin transplanted onto SCID mice were treated topically with BP-1107. In brief, 100 µl of solution— either DMSO alone or BP-1107 (100 µM) in DMSO—was applied daily for 21 days. At the end of the treatment period, animals were sacrificed. The transplanted skin with a small amount of surrounding mouse skin was removed and fixed in 10% buffered formalin. After staining with hematoxylin and eosin, skin sections were examined by light microscopy. Tissue sections were visualized by light microscopy at 200x magnification. Epidermal thickness measurements were made at four or more sites on three or four different histological sections from each transplant (two control and two BP-1107-treated biopsies per subject) and averaged. From these values, mean epidermal thickness was determined.
Human Epidermal Keratinocytes and Dermal Fibroblasts in Monolayer Culture. Normal human epidermal keratinocytes were isolated as described previously (Varani et al., 1994). Primary and early passage cells were maintained in keratinocyte growth medium (KGM) (Cambrex Bio Science Walkersville, Walkersville, MD). KGM is a modification of MCDB-153 medium containing a low level (0.15 mM) of extracellular Ca2+ and further supplemented with a mixture of growth factors, including 0.1 ng/ml EGF, 0.5 µg/ml insulin, and 2% bovine pituitary extract. Fibroblasts were obtained from the same tissue and grown in monolayer culture using Dulbecco's modified Eagle's medium supplemented with nonessential amino acids and 10% fetal bovine serum. Both keratinocytes and fibroblasts were maintained at 37°C in an atmosphere of 95% air and 5% CO2. Cells were subcultured by exposure to EDTA and used at passage 2 to 3.
Proliferation Assays. For dose-response studies, keratinocytes and fibroblasts were seeded at 5 x 104 cells/well in their respective growth media (24-well plate) and allowed to attach overnight. Cells were treated with different concentrations of BP-1107. Proliferation was measured on day 3 by releasing the cells with trypsin/EDTA and enumerating them using a particle counter (Beckman Coulter, Inc., Fullerton, CA). For time-course studies, 5 x 104 cells were seeded per well in a 24-well plate, allowed to attach overnight, and treated with 1 µM BP-1107. Cell counts were made on days 1 through 3. KGM was used for keratinocyte proliferation studies, and KBM supplemented with 1.4 mM Ca2+ was used for fibroblast proliferation assays. KBM consists of the same basal medium as KGM but is not supplemented with growth factors.
Cytotoxicity Assays. Keratinocytes were plated at 5 x 104 cells/well in KGM and incubated overnight to allow the cells to attach. On the next day, cells were exposed to control conditions or to different concentrations of BP-1107 for 4 h. At the end of the incubation period, the cells were harvested, counted, and replated in growth medium. Eighteen hours later, the percentage of cells that had reattached and spread was determined. The ability of cells to reattach and spread after treatment was used as a measure of cell viability (Varani et al., 1985).
Motility Assay. Motility was assessed using the "scratch wound" assay. The cells were seeded into a 24-well dish at 1 x 105 cells/well and incubated in KGM to near confluence. At that point, a scratch-wound approximately 100 µm in width was made through the monolayer. The wounded monolayers were incubated in KGM with different concentrations of BP-1107 for 2 days. At the end of the incubation period, the cultures were photographed under phase-contrast microscopy at 200x magnification. The distance the cells migrated into the wounded area was measured using a micrometer.
MMP Assays. Keratinocyte- or fibroblast-conditioned medium was assayed for MMP activity. SDS-PAGE substrate embedded enzymography (zymography) was used to identify enzymes with gelatinase activity. Assays were carried out as described in a previous report (Gibbs et al., 1999). In brief, denatured but nonreduced culture fluid samples were resolved in 10% SDS-PAGE gels prepared with incorporation of gelatin (1 mg/ml) before casting. After electrophoresis, gels were washed twice for 15 min in 50 mM Tris buffer containing 1 mM Ca2+, 0.5 mM Zn2+, and 2.5% Triton X-100. The gels were then incubated overnight in Tris buffer with 1% Triton X-100 and stained the next day with Brilliant Blue 250-R. After destaining, zones of enzyme activity were detected as regions of negative staining against the dark background. Gelatin zymography is used for detection of MMP-2 (72-kDa gelatinase A) and MMP-9 (92-kDa gelatinase B).
Fibroblast-conditioned medium was assayed for MMP-1 (interstitial collagenase) by Western blotting as described previously (Bhagavathula et al., 2004). In brief, samples were separated in 10% SDS-PAGE under denaturing and reducing conditions and transferred to nitrocellulose membranes. After blocking with a 5% nonfat milk solution in Tris-buffered saline at 4°C overnight, membranes were incubated for 1 h at room temperature with a rabbit polyclonal anti-human MMP-1 antibody, diluted 1:6000 in 0.5% nonfat milk/0.1% Tween 20-Tris-buffered saline. Thereafter the membranes were washed with 0.1% Tween 20-Tris-buffered saline and bound antibody detected using the Phototope-HRP Western blot detection kit (Cell Signaling Technology Inc.).
Type I Procollagen Assay. Fibroblast-conditioned medium was assayed for type I procollagen by enzyme-linked immunosorbent assay (Pan Vera Corp., Madison, WI) as described previously (Varani et al., 2000). The procollagen assay uses an antibody to the C-terminal propeptide region that is part of the collagen molecule as it is synthesized and secreted (before being proteolytically cleaved). As such, this assay is a measure of newly synthesized collagen.
Preparation of Cell Lysates and Immunoblot Analysis of Signaling Intermediates. Cells were lysed in 1x cell lysis buffer (Cell Signaling Technology Inc.). Lysis was performed at 4°C by scraping the cells into lysis buffer and sonicating the samples. Cell lysates were incubated on ice for 30 min and then cleared by microcentrifugation at 16,000g for 15 min. The supernatant fluids were collected and protein concentration was estimated using the Bio-Rad DC protein assay kit (Bio-Rad, Hercules, CA). Cell extracts containing equivalent amounts of protein (40 µg of total protein per lane) were electrophoresed in 10% SDS-polyacrylamide gels. Western blotting for signaling intermediates was carried out as described above for MMP-1.
Statistical Analysis. Measurements were expressed as means ± S.E. or means ± S.D. Statistical analyses were carried out using the Student's t test where two groups were compared or by analysis of variance followed by paired group comparisons where there were multiple groups. p < 0.05 was considered statistically significant.
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Results |
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In addition to transplanting and treating psoriatic plaque skin, skin from four nonpsoriatic donors was also transplanted to SCID mice and treated topically with BP-1107. With nonpsoriatic skin samples, BP-1107 was used at two concentrations (25 and 100 µM). Consistent with past reports (Zeigler et al., 2001; Bhagavathula et al., 2005), skin from nonpsoriatic tissue donors became hyperplastic upon transplantation. When the nonpsoriatic skin transplants were treated topically with a 100 µM concentration, findings were similar to those with psoriatic skin, i.e., shrinkage of the tissue and areas of epidermal erosion were observed. These gross changes were not observed in animals treated with the lower concentration. Histological findings including thinning of the epidermis with loss of rete pegs and ridges were observed with both drug concentrations (Fig. 3).
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In contrast to these results, exposure of cells to higher concentrations of BP-1107 (10–20 µM) was cytotoxic. Specifically, the number of cells recovered from wells at the end of the 3-day incubation period was fewer than the number plated (indicative of cell killing) and this was verified by cell death in the 4-h cytotoxicity assay (not shown).
Keratinocyte motility was assessed next. As shown in Fig. 6, cell migration was inhibited in the presence of BP-1107. The dose-response for inhibition of motility (ED50 = 0.55 µM) was slightly lower than that for proliferation.
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Effects of BP-1107 on Intracellular Signaling Events That Underlie Proliferation, Motility, and MMP Production in Keratinocytes. Previous studies have demonstrated the importance of mitogen-activated protein kinase signaling (in particular, signaling through the ERK1/2 pathway) to EGF-induced biological events in keratinocytes (Zeigler et al., 1999). To determine whether the inhibitory effects of BP-1107 on keratinocyte function could be related to interference with mitogen-activated protein kinase signaling, we assessed the effects of the synthetic PPAR- agonist on ERK1/2 phosphorylation in EGF-stimulated keratinocytes. For this experiment, keratinocytes were treated with 10 ng/ml EGF in the absence or presence of BP-1107. At various times later, ERK1/2 phosphorylation was assessed. Inhibition was seen as early as 5 min after EGF stimulation, was maximal at 15 min, and gradually returned to baseline by 120 min (Fig. 7). In addition to the rapid/transient reduction in the phosphorylation of both ERK1 and ERK2, there was also a longer sustained reduction. This was observed by assessing phospho-ERK1/2 levels in control and BP-1107-treated keratinocytes after 1 and 2 days of treatment. On both days, the levels of phospho-ERK1/2 were lower in treated than control cells (Fig. 7). In contrast to effects on phospho-ERK1/2, there was no measurable effect of BP-1107 treatment on total ERK1/2 levels in either the short-term (5- to 120-min) or long-term (1- and 2-day) studies.
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In a final set of experiments, we examined the ability of BP-1107 to reduce c-Jun phosphorylation in keratinocytes. In contrast to what was observed with ERK1/2, treatment with BP-1107 produced essentially no change in the amount of phosphorylated c-Jun seen in keratinocytes over a 6-h time period after EGF stimulation (not shown). Likewise, there was no change in total c-Jun expression. The lack of effect on c-Jun is of interest since there was no change in MMP-9 expression under the same conditions. Previous studies have shown a role of c-Jun in MMP-9 induction (Fisher et al., 1998).
Effects of BP-1107 on Fibroblast Function in Monolayer Culture. In addition to assessing BP-1107 on keratinocyte function, human dermal fibroblasts isolated from the same skin samples as the keratinocytes were also examined for response to BP-1107. Fibroblast proliferation and procollagen synthesis proved to be resistant to the effects of this agent. When treated with a concentration of 1 µM, there was no significant effect on fibroblast proliferation over the 3-day observation period (Fig. 8, top). Likewise, there was no inhibition of type I procollagen elaboration under the same conditions (Fig. 8, middle). On the other hand, fibroblast production of MMP-1 (interstitial collagenase), which is the major collagen-degrading enzyme in human skin (Brennan et al., 2003), was reduced in the presence of BP-1107 (Fig. 8, bottom).
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Discussion |
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; Ellis et al., 2000). Subsequently, it was demonstrated in controlled studies that these synthetic PPAR- agonists were potent suppressors of epithelial proliferation and inducers of epithelial differentiation (Komuves et al., 1998; Kubota et al., 1998; Mueller et al., 1998; Rivier et al., 1998, 2000; Sarraf et al., 1998; Ellis et al., 2000; Mao-Qiang et al., 2004). Our own studies confirmed the growth-suppressing effects of troglitazone, rosiglitazone, and other synthetic thiazolidinediones on human epidermal keratinocytes (Ellis et al., 2000; Bhagavathula et al., 2004; Venkatraman et al., 2004). Motility, another commonly observed feature in psoriatic keratinocytes, was also substantially down-regulated after treatment with rosiglitazone (Bhagavathula et al., 2004).
In a significant subset of patients, systemic administration of thiazolidinediones is associated with several disconcerting side effects, including fluid retention, edema, and weight gain. Although systemic delivery may be required for treatment of conditions such as type II diabetes, psoriasis is, at least in some individuals, amenable to topical therapy. If agents with PPAR- agonist activity could be delivered topically, many of the unwanted effects associated with systemic delivery might be averted. In the present study, we demonstrate that topical treatment of human psoriatic skin transplants on SCID mice with a novel, adamantyl-coupled thiazolidinedione (BP-1107) significantly reduces the hyperplasia and normalizes differentiation in the transplanted skin.
Our previous studies have demonstrated that normal human skin becomes hyperplastic as a consequence of transplantation to SCID mice (Zeigler et al., 2001). Therapeutic approaches that interfere with the immune basis of psoriasis (i.e., cyclosporine and anti-CD11a) inhibited psoriatic hyperplasia but not the hyperplasia developing in normal skin upon transplantation. In contrast, agents that interfere with the biochemical events that are directly involved in keratinocyte growth control (i.e., antibody to amphiregulin and corticosteroids) suppressed hyperplasia in both normal and psoriatic skin (Zeigler et al., 2001; Bhagavathula et al., 2005). Not surprisingly, given what is known about PPAR- receptors in epidermal growth control, BP-1107 was found to suppress the reactive hyperplasia in nonpsoriatic skin transplants as well as the hyperplasia in the psoriatic skin transplants. Likewise, inhibition of human epidermal keratinocyte proliferation in monolayer was also demonstrated with BP-1107, as was down-regulation of keratinocyte motility. In these regards, the effects of BP-1107 were similar to those we have reported previously with troglitazone and rosiglitazone (Ellis et al., 2000; Bhagavathula et al., 2004), the differences being that BP-1107 functions at significantly lower concentrations than the other thiazolidinediones and works in vivo after topical application.
In addition to assessing effects on keratinocyte function, BP-1107 was also examined for effects on dermal fibroblasts. No detrimental effects on fibroblast proliferation or type I procollagen elaboration were seen at concentrations that effectively interfered with epidermal proliferation. Unexpectedly, MMP-1 (interstitial collagenase) production was significantly suppressed by BP-1107. The mechanism of MMP-1 suppression or its possible significance is not yet known. Given these actions of topical BP-1107 in the epidermis and dermis, one might expect antipsoriatic activity without the dermal atrophy associated with corticosteroid use. On the other hand, since BP-1107 seems to function at the keratinocyte level to suppress epidermal hyperplasia, there is the possibility for erosion of the reactive epidermis at the edge of the psoriatic lesion. Likewise, the possibility exists that the normal wound-healing response would be disturbed. Additional studies will be needed to determine whether these consequences materialize. Regardless, topical use of the agent is unlikely to produce a generalized effect on normal epidermal function or on wound healing.
The findings presented here may help advance understanding of how thiazolidinediones function in psoriasis. The pathophysiology of psoriasis is complex and multifaceted. A T cell-mediated immune response is involved in the initiation of psoriatic lesions, but a variety of studies suggest that intraepidermal events directly mediate hyperplastic epidermal growth. In particular, hyperplastic epidermal proliferation in psoriatic lesional skin is thought to reflect autocrine or paracrine stimulation through the EGF receptor. Ligands for the EGF receptor, including transforming growth factor-, amphiregulin, and heparin-binding EGF are elevated in psoriatic lesional skin and/or in psoriatic keratinocytes relative to control skin/cells (Gottlieb et al., 1988; Elder et al., 1989; Cook et al., 1992; Piepkorn et al., 1998, 2003). Amphiregulin may be particularly important, since transgenic mice overexpressing the amphiregulin gene develop a psoriasiform phenotype (Cook et al., 1997, 2004). Furthermore, our own recent studies have shown that interfering with human amphiregulin in the human skin-SCID mouse model suppresses hyperplasia in the transplanted skin (Bhagavathula et al., 2005). Although thiazolidinediones do not seem to interfere with the initial ligand-receptor-mediated events (Bhagavathula et al., 2004), by interfering with downstream signaling events (i.e., ERK1/2 activation), these agents prevent the cellular responses to EGF receptor activation that control proliferation.
Although the findings presented here strongly suggest that a direct effect of the thiazolidinediones on keratinocyte function contributes to their antipsoriatic activity, this does not rule out additional effects mediated through immune modulation. A number of PPAR- agonists, including members of the thiazoladinedine family, have been shown to be beneficial in immune/inflammatory conditions (Augstein et al., 2003; Culver et al., 2004; Hasegawa et al., 2005; Schaefer et al., 2005). Efficacy is presumed to reflect modulation of the Th1/Th2 cytokine balance. Obviously, antiproliferative activity for keratinocytes and modulation of immune function are not mutually exclusive. Additional studies will be necessary to completely delineate the relative importance of these activities to the overall antipsoriatic activity of the thiazolidinedione compounds.
In summary, the findings presented here demonstrate that a novel high-affinity PPAR- ligand, consisting of an adamantyl-coupled thiazolidinedione, reduces epidermal hyperplasia of human skin transplanted to SCID mice. Inhibition is observed after topical treatment, suggesting that effective antipsoriatic therapy may be provided without the inherent consequences observed with systemic use of this class of agents. Given these findings, it is reasonable to consider further development of BP-1107 as a topical agent for use in psoriasis and perhaps in other conditions in which epidermal hyperplasia constitutes a major part of the pathology.
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Acknowledgements |
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Footnotes |
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H.A.P. and T.W.K. have equity in Bethesda Pharmaceuticals, Inc. and could have financial gain if the drug under study proves to be effective.
ABBREVIATIONS: Th, T-helper; IL, interleukin; PPAR-, peroxisome proliferator-activated receptor-; SCID, severe-combined immunodeficient; BP-1107, {2-[4-(2,4-dioxo-thiazolidin-5-ylmethyl)-phenoxy]-ethyl}-methyl-amide; ERK, extracellular signal-regulated kinase; MMP, matrix metalloproteinase; EGF, epidermal growth factor; DMSO, dimethyl sulfoxide; KGM, keratinocyte growth medium; KBM, keratinocyte basal medium; PAGE, polyacrylamide gel electrophoresis.
Address correspondence to: Dr. James Varani, Department of Pathology, The University of Michigan, 1301 Catherine Rd., Box 0602, Ann Arbor, MI 48109. E-mail: varani{at}umich.edu
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References |
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TopAbstractMaterials and MethodsResultsDiscussionReferences |
|---|
Augstein P, Dunger A, Heinke P, Wachlin G, Berg S, Hehmke B, and Salzsieder E (2003) Prevention of autoimmune diabetes in NOD mice by troglitazone is associated with modulation of ICAM-1 expression on pancreatic islet cells and IFN-gamma expression in splenic T cells. Biochem Biophys Res Commun 304: 378–384.[CrossRef][Medline]
Austin LM, Ozawa M, Kikuchi T, Walters IB, and Krueger JG (1999) The majority of epidermal T cells in Psoriasis vulgaris lesions can produce type 1 cytokines, interferon-gamma, interleukin-2 and tumor necrosis factor-alpha, defining TC1 (cytotoxic T lymphocyte) and TH1 effector populations: a type 1 differentiation bias is also measured in circulating blood T cells in psoriatic patients. J Investig Dermatol 113: 752–759.[CrossRef][Medline]
Bhagavathula N, Nerusu KC, Fisher GJ, Liu G, Thakur AB, Gemmell L, Kumar S, Xu ZH, Hinton P, Tsurushita N, et al. (2005) Amphiregulin and epidermal hyperplasia: amphiregulin is required to maintain the psoriatic phenotype of human skin grafts on severe combined immunodeficient mice. Am J Pathol 166: 1009–1016.
Bhagavathula N, Nerusu KC, Lal A, Ellis CN, Chittiboyina A, Avery MA, Ho CI, Benson SC, Pershadsingh HA, Kurtz TW, et al. (2004) Rosiglitazone inhibits proliferation, motility and matrix metalloproteinase production in keratinocytes. J Investig Dermatol 122: 130–139.[CrossRef][Medline]
Brennan M, Bhatti H, Nerusu KC, Bhagavathula N, Kang S, Fisher GJ, Varani J, and Voorhees JJ (2003) Matrix metalloproteinase-1 is the major collagenolytic enzyme responsible for collagen damage in UV-irradiated human skin. Photochem Photobiol 78: 43–48.[CrossRef][Medline]
Cook PW, Brown JR, Cornell KA, and Pittelkow MR (2004) Suprabasal expression of human amphiregulin in the epidermis of transgenic mice induces a severe, early-onset, psoriasis-like skin pathology: expression of amphiregulin in the basal epidermis is also associated with synovitis. Exp Dermatol 13: 347–356.[CrossRef][Medline]
Cook PW, Piepkorn M, Clegg CH, Plowman GD, DeMay JM, Brown JR, and Pittelkow MR (1997) Transgenic expression of the human amphiregulin gene induces a psoriasis-like phenotype. J Clin Investig 100: 2286–2294.[Medline]
Cook PW, Pittelkow MR, Keeble WW, Graves-Deal R, Coffey RJ Jr, and Shipley GD (1992) Amphiregulin messenger RNA is elevated in psoriatic epidermis and gastrointestinal carcinomas. Cancer Res 52: 3224–3227.
Culver DA, Barna BP, Raychaudhuri B, Bonfield TL, Abraham S, Malur A, Farver CF, Kavuru MS, and Thomassen MJ (2004) Peroxisome proliferator-activated receptor gamma activity is deficient in alveolar macrophages in pulmonary sarcoidosis. Am J Respir Cell Mol Biol 30: 1–5.
Elder JT, Fisher GJ, Lindquist PB, Bennett GL, Pittelkow MR, Coffey RJ Jr, Ellingsworth L, Derynck R, and Voorhees JJ (1989) Overexpression of transforming growth factor alpha in psoriatic epidermis. Science (Wash DC) 243: 811–814.
Ellis CN, Varani J, Fisher GJ, Zeigler ME, Pershadsingh HA, Benson SC, Chi Y, and Kurtz TW (2000) Troglitazone improves psoriasis and normalizes models of proliferative skin disease: ligands for peroxisome proliferator-activated receptor-gamma inhibit keratinocyte proliferation. Arch Dermatol 136: 609–616.
Fisher GJ, Talwar HS, Lin J, Lin P, McPhillips F, Wang Z, Li X, Wan Y, Kang S, and Voorhees JJ (1998) Retinoic acid inhibits induction of c-Jun protein by ultraviolet radiation that occurs subsequent to activation of mitogen-activated protein kinase pathways in human skin in vivo. J Clin Investig 101: 1432–1440.[Medline]
Gibbs DF, Warner RL, Weiss SJ, Johnson KJ, and Varani J (1999) Characterization of matrix metalloproteinases produced by rat alveolar macrophages. Am J Respir Cell Mol Biol 20: 1136–1144.
Gilhar A, David M, Ullmann Y, Berkutski T, and Kalish RS (1997) T-lymphocyte dependence of psoriatic pathology in human psoriatic skin grafted to SCID mice. J Investig Dermatol 109: 283–288.[CrossRef][Medline]
Gottlieb AB, Chang CK, Posnett DN, Fanelli B, and Tam JP (1988) Detection of transforming growth factor alpha in normal, malignant and hyperproliferative human keratinocytes. J Exp Med 167: 670–675.
Hasegawa H, Takano H, Zou Y, Qin Y, Hizukuri K, Odaka K, Toyozaki T, and Komuro I (2005) Pioglitazone, a peroxisome proliferator-activated receptor gamma activator, ameliorates experimental autoimmune myocarditis by modulating Th1/Th2 balance. J Mol Cell Cardiol 38: 257–265.[CrossRef][Medline]
Komuves LG, Hanley K, Jiang Y, Elias PM, Williams ML, and Feingold KR (1998) Ligands and activators of nuclear hormone receptors regulate epidermal differentiation during fetal rat skin development. J Investig Dermatol 111: 429–433.[CrossRef][Medline]
Kubota T, Koshizuka K, Williamson EA, Asou H, Said JW, Holden S, Miyoshi I, and Koeffler HP (1998) Ligand for peroxisome proliferator-activated receptor gamma (troglitazone) has potent antitumor effect against human prostate cancer both in vitro and in vivo. Cancer Res 58: 3344–3352.
Lebovitz HE (2002) Differentiating members of the thiazolidinedione class: a focus on safety. Diabetes Metab Res Rev 18 (Suppl 2): S23–S29.
Mao-Qiang M, Fowler AJ, Schmuth M, Lau P, Chang S, Brown BE, Moser AH, Michalik L, Desvergne B, Wahli W, et al. (2004) Peroxisome-proliferator-activated receptor (PPAR)-gamma activation stimulates keratinocyte differentiation. J Investig Dermatol 123: 305–312.[CrossRef][Medline]
Mueller E, Sarraf P, Tontonoz P, Evans RM, Martin KJ, Zhang M, Fletcher C, Singer S, and Spiegelman BM (1998) Terminal differentiation of human breast cancer through PPAR gamma. Mol Cell 1: 465–470.[CrossRef][Medline]
Nickoloff BJ (1991) The cytokine network in psoriasis. Arch Dermatol 127: 871–884.
Nickoloff BJ, Kunkel SL, Burdick M, and Strieter RM (1995) Severe combined immunodeficiency mouse and human psoriatic skin chimeras. Validation of a new animal model. Am J Pathol 146: 580–588.[Abstract]
Pershadsingh HA, Sproul JA, Benjamin E, Finnegan J, and Amin NM (1998) Treatment of psoriasis with troglitazone therapy. Arch Dermatol 134: 1304–1305.
Piepkorn M, Pittelkow MR, and Cook PW (1998) Autocrine regulation of keratinocytes: the emerging role of heparin-binding, epidermal growth factor-related growth factors. J Investig Dermatol 111: 715–721.[CrossRef][Medline]
Piepkorn M, Predd H, Underwood R, and Cook P (2003) Proliferation-differentiation relationships in the expression of heparin-binding epidermal growth factor-related factors and erbB receptors by normal and psoriatic human keratinocytes. Arch Dermatol Res 295: 93–101.[CrossRef][Medline]
Rivier M, Castiel I, Safonova I, Ailhaud G, and Michel S (2000) Peroxisome proliferator-activated receptor-alpha enhances lipid metabolism in a skin equivalent model. J Investig Dermatol 114: 681–687.[CrossRef][Medline]
Rivier M, Safonova I, Lebrun P, Griffiths CE, Ailhaud G, and Michel S (1998) Differential expression of peroxisome proliferator-activated receptor subtypes during the differentiation of human keratinocytes. J Investig Dermatol 111: 1116–1121.[CrossRef][Medline]
Robertshaw H and Friedmann PS (2005) Pioglitazone: a promising therapy for psoriasis. Br J Dermatol 152: 189–191.[CrossRef][Medline]
Sarraf P, Mueller E, Jones D, King FJ, DeAngelo DJ, Partridge JB, Holden SA, Chen LB, Singer S, Fletcher C, et al. (1998) Differentiation and reversal of malignant changes in colon cancer through PPAR. Nat Med 4: 1046–1052.[CrossRef][Medline]
Schaefer KL, Denevich S, Ma C, Cooley SR, Nakajima A, Wada K, Schlezinger J, Sherr D, and Saubermann LJ (2005) Intestinal antiinflammatory effects of thiazolidenedione peroxisome proliferator-activated receptor-gamma ligands on T helper type 1 chemokine regulation include nontranscriptional control mechanisms. Inflamm Bowel Dis 11: 244–252.[CrossRef][Medline]
Shafiq N, Malhotra S, Pandhi P, Gupta M, Kumar B, and Sandhu K (2005) Pilot trial: pioglitazone versus placebo in patients with plaque psoriasis (the P6). Int J Dermatol 44: 328–333.[CrossRef][Medline]
Valdimarsson H, Baker BS, Jonsdottir I, Powles A, and Fry L (1995) Psoriasis: a T-cell-mediated autoimmune disease induced by streptococcal superantigens? Immunol Today 16: 145–149.[CrossRef][Medline]
Varani J, Fligiel SE, Till GO, Kunkel RG, Ryan US, and Ward PA (1985) Pulmonary endothelial cell killing by human neutrophils. Possible involvement of hydroxyl radical. Lab Investig 53: 656–663.[Medline]
Varani J, Perone P, Griffiths CE, Inman DR, Fligiel SE, and Voorhees JJ (1994) All-trans retinoic acid (RA) stimulates events in organ-cultured human skin that underlie repair. Adult skin from sun-protected and sun-exposed sites responds in an identical manner to RA while neonatal foreskin responds differently. J Clin Investig 94: 1747–1756.
Varani J, Warner RL, Gharaee-Kermani M, Phan SH, Kang S, Chung JH, Wang ZQ, Datta SC, Fisher GJ, and Voorhees JJ (2000) Vitamin A antagonizes decreased cell growth and elevated collagen-degrading matrix metalloproteinases and stimulates collagen accumulation in naturally aged human skin. J Investig Dermatol 114: 480–486.[CrossRef][Medline]
Venkatraman MS, Chittiboyina A, Meingassner J, Ho CI, Varani J, Ellis CN, Avery MA, Pershadsingh HA, Kurtz TW, and Benson SC (2004) -Lipoic acid-based PPAR agonists for treating inflammatory skin diseases. Arch Dermatol Res 296: 97–104.[Medline]
Wrone-Smith T and Nickoloff BJ (1996) Dermal injection of immunocytes induces psoriasis. J Clin Investig 98: 1878–1887.[Medline]
Zeigler M, Chi Y, Tumas DB, Bodary S, Tang H, and Varani J (2001) Anti-CD11a ameliorates disease in the human psoriatic skin-SCID mouse transplant model: comparison of antibody to CD11a with Cyclosporin A and clobetasol propionate. Lab Investig 81: 1253–1261.[CrossRef][Medline]
Zeigler ME, Chi Y, Schmidt T, and Varani J (1999) Role of ERK and JNK pathways in regulating cell motility and matrix metalloproteinase 9 production in growth factor-stimulated human epidermal keratinocytes. J Cell Physiol 180: 271–284.[CrossRef][Medline]
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