Inhibitory activity of CX-659S, a novel diaminouracil derivative, against the rebound phenomenon following withdrawal of corticosteroid therapy for chronic contact hypersensitivity responses

Corydalis tomentella Franch. Exerts anti-inflammatory and analgesic effects by regulating the calcium signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Corydalis tomentella Franch. is a perennial cespitose plant commonly used to treat stomachaches as a folk medicine. The C. tomentella total alkaloids have good protective effects against acute liver injury and potential anti-hepatoma and anti-Alzheimer's disease activities.

AIM OF THE STUDY

To establish an effective purification process for total alkaloids from C. tomentella and investigate the mechanism of their anti-inflammatory effects.

MATERIALS AND METHODS

Corydalis tomentella were purified using macroporous resin. Then the crude and purified C. tomentella extracts (cCTE and pCTE) were qualitatively analyzed using UPLC-Triple-TOF-MS/MS. The cCTE and pCTE were used to investigate and compare their anti-inflammatory effects on lipopolysaccharide (LPS)-induced RAW264.7 cells. Doses at 100, 200 and 400 mg/kg/d of pCTE were used to study their anti-inflammatory and analgesic activities in mice with xylene-induced ear swelling and acetic acid-induced writhing tests. Content of nitric oxide (NO), interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) were determined both in RAW264.7 cells and mice. Network pharmacology was used to predict the anti-inflammatory mechanism of C. tomentella, and the key enzymes were validated using qPCR and Western Blot analysis. Concentration of intracellular Ca2+ was detected using flow cytometric analysis.

RESULTS

The C. tomentella total alkaloid purity increased from 6.29% to 47.34% under optimal purification conditions. A total of 54 alkaloids were identified from CTE. Both cCTE and pCTE could suppress the LPS-induced production of NO, IL-6, IL-1β, and TNF-α in RAW264.7 cells. The pCTE exhibited a more potent anti-inflammatory effect; it also inhibited pain induced by xylene and acetic acid in mice. The calcium signaling pathway is associated with the anti-inflammatory and analgesic activities of C. tomentella. The mRNA expression of nitric oxide synthase (NOS) 2, NOS3 and calmodulin1 (CALM1) was regulated by C. tomentella through the reduction of inflammation-induced Ca2+ influx, and it also exhibited a more pronounced effect than the positive control (L-NG-nitro arginine methyl ester).

CONCLUSIONS

Purified C. tomentella extract shows anti-inflammatory effect both in vitro and in vivo. It exerts anti-inflammatory and analgesic effects through the calcium signaling pathway by down-regulating NOS2 and CALM1 expression and up-regulating NOS3 expression in LPS-induced RAW264.7 cells, and decreasing intracellular Ca2+ concentration.

Inhibitory effect of timolol on topical glucocorticoid‑induced skin telangiectasia

The aim of the present study wasto investigate the potential inhibitory effect of timolol on topical glucocorticoid-induced skin telangiectasia. In rabbits, flumethasone ointment was used to induce skin telangiectasia in the inner ear. Subsequently, timolol maleate (0.5%) eye drops (TMEDs) were administered twice daily for 4 weeks. Expression of the antibacterial peptides 37-amino acid peptide (LL-37) and kallikrein-5 (KLK5) was detected using quantitative polymerase chain reaction (PCR) and semi-quantitative reverse transcription-PCR. In patients with facial skin telangiectasia, one cheek of each patient was assigned to a treatment group and the other to a control group. For the treatment group cheeks, topical application of TMEDs was combined with 0.1% tacrolimus ointment once or twice daily for 8 weeks. The control group cheeks were administered with 0.1% tacrolimus ointment alone. Alterations in lesions were recorded by dermoscopy, and the L, a and b values of lesions were measured, based on the Commission Internationale de l'Éclairage system, with a chromameter prior to and at 1, 2, 4 and 8 weeks following treatment. The results indicated that erythema, papules and telangiectasia were significantly diminished following 4 weeks of treatment with TMEDs in rabbits. Notably, the expression of LL-37 and KLK5 mRNA was increased in the negative control group; however, it was decreased in the trial and blank groups. Clinical and dermoscopy images demonstrated that erythema was reduced in the 2 groups for 1 week, and that telangiectasia in the treatment group was markedly reduced compared with the control group at 4 weeks. The difference of the L and a values of lesions between the treatment and control group was significant (P<0.05). Overall, the present results suggested that the abnormal expression of LL-37 may be one of the mechanisms underlying the pathogenesis of facial corticosteroid addiction dermatitis (FCAD) and TMEDs may inhibit the mRNA expression of LL-37 by downregulating KLK5; in this regard, TMEDs may serve a role in attenuating telangiectasia, which may be beneficial in improving the telangiectasia symptoms of FCAD.

Anti-inflammatory and Anti-oxidative Effects of Korean Red Ginseng Extract in Human Keratinocytes

BACKGROUND

In this study, we have investigated the effect of Korean red ginseng (KRG) extracts on the production of TNF-α and IL-8 in human keratinocytes. Also, to examine the antioxidative effect of red ginseng extracts, free radical scavenging activity and superoxide dismutase (SOD) activity in human dermal fibroblasts was measured.

METHODS

To investigate the effect of KRG in atopic dermatitis, we measured the level of TNF-α and IL-8 secretion in LPS-stimulated human keratinocytes after the treatment of KRG extracts using enzyme-linked immunosorbent assay. Anti-oxidative activity was investigated by measuring 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and SOD activity.

RESULTS

The stimulation of human keratinocytes with KRG extracts shifted the LPS-induced cytokine secretion toward a more immunosuppressive response. KRG dose-dependently decreased TNF-α and IL-8 production in HaCaT cells and a significant inhibition of TNF-α was shown when cells were treated with 500 and 1,000 µg/ml of KRG extracts. Additionally, KRG extracts showed DPPH radical scavenging and SOD activity in a dose-dependent manner. Particularly, SOD activities of concentrations higher than 60 µg/ml of KRG extracts were significantly different in human dermal fibroblast cells.

CONCLUSION

Based on this study, KRG extracts may be a useful immunosuppressive agent in the treatment of atopic dermatitis.

A novel organogermanium protected atopic dermatitis induced by oxazolone

Atopic dermatitis (AD) is a chronic inflammatory disease of the skin that is often associated with other atopic diseases, such as asthma and allergic rhinitis. Although topical steroids have widely been prescribed for patients with AD, skin abnormalities are frequently observed after prolonged steroid treatment. In this study, a novel water-soluble organogermanium compound (Ge-Vit) was prepared because organogermanium is a known INF-gamma inducer. The Ge-Vit treatment decreased the basal TEWL and IgE production and attenuated the disruption of the skin barrier function in a murine model of chronic contact dermatitis. The histological examination further supported the anti-AD activities. These results suggested that Ge-Vit can be a useful drug candidate for treating atopic dermatitis.

Scratching behavior does not necessarily correlate with epidermal nerve fiber sprouting or inflammatory cell infiltration

BACKGROUND

Increased sprouting of epidermal nerve fibers of lesional skin are thought to be associated with persistent pruritus in chronic inflammatory dermatitis such as atopic dermatitis as supported by a murine study using tacrolimus (or FK506: FK) which was shown to inhibit both epidermal sprouting of nerves and scratching behavior or by immunohistochemical observations of lesional skin in the patients with atopic dermatitis or prurigo, etc.

OBJECTIVES

To examine a mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 (MEK1/2) inhibitor (CX-659S: CX) for a possible anti-pruritic property in vivo since some MEK1/2 inhibitors have been reported to inhibit neurite growth in vitro.

METHODS

CX, FK and corticosteroids (betamethasone valerate: BV) were topically applied on inflamed skin in a mouse model of chronic dermatitis using repetitive hapten painting to examine anti-pruritic property and anti-inflammatory effects. Scratching behaviors were assessed using MicroAct automatic measuring system, and epidermal sprouting of nerves and skin inflammation was assessed histologically.

RESULTS

FK significantly decrease scratching behavior, but CX and BV failed to do so despite of their ability to significantly inhibit epidermal nerve fiber sprouting and skin inflammation, respectively. In addition, CX+BV mixture synergistically inhibited epidermal nerve fiber sprouting and skin inflammation even more potently than FK without decreasing scratching behavior.

CONCLUSIONS

These findings suggest that the scratching behavior does not necessarily correlate with epidermal nerve fiber sprouting or inflammatory cell infiltration.

Inhibitory effect of a potent and selective cytosolic phospholipase A2alpha inhibitor RSC-3388 on skin inflammation in mice

Cytosolic phospholipase A2alpha (cPLA2alpha) preferentially hydrolyzes membrane phospholipids containing arachidonic acid, resulting in the biosynthesis of eicosanoids such as prostaglandins and leukotrienes. To examine the contribution of cPLA2alpha to skin inflammation, we evaluated the effect of (E)-N-[(2S,4R)-4-[N-(biphenyl-2-ylmethyl)-N-2-methylpropylamino]-1-[2-(2,4-difluorobenzoyl)benzoyl]pyrrolidin- 2-yl]methyl-3-[4-(2,4-dioxothiazolidin-5-ylidenemethyl) phenyl]acrylamide (RSC-3388), a potent and selective cPLA2alpha inhibitor, on 2,4,6-trinitro-1-chlorobenzene (TNCB)-induced ear inflammation and mite antigen-induced dermatitis in mice. Topical application of RSC-3388 showed a significant inhibitory activity against TNCB-induced ear swelling and eicosanoid production in mice. Comprehensive expression analysis using Gene-Chip technology and subsequent experiments concerning mRNA and protein expression demonstrated that RSC-3388 clearly reduced the levels of interleukin-1beta, macrophage inflammatory protein-1alpha (MIP-1alpha) and MIP-1beta in a TNCB-induced mouse model. In addition, RSC-3388 ointment significantly alleviated atopic dermatitis-like skin lesions induced by repeated application of mite antigen. Furthermore, increased expression of cPLA(2)alpha, assessed by anti-phospho-cPLA2alpha antibody, was observed in the skin lesions of mite-antigen-induced dermatitis. These results indicate that cPLA2alpha is involved in the development of skin inflammation in mice, and RSC-3388 is expected to be useful for the treatment of inflammatory skin disorders such as atopic dermatitis.

Inhibitory or scavenging action of ketoconazole and ciclopiroxolamine against reactive oxygen species released by primed inflammatory cells

BACKGROUND

Reactive oxygen species (ROS) released from inflammatory cells constitute one of the critical causative factors in inflammatory skin diseases such as seborrhoeic dermatitis and atopic dermatitis.

OBJECTIVES

To investigate inhibitory effects of ketoconazole (KCZ) and ciclopiroxolamine (CPO), both of which have been used for the treatment of seborrhoeic dermatitis, on ROS released from inflammatory cells.

METHODS

The methyl-Cypridina-luciferin analogue-dependent chemiluminescence method was employed for the detection of ROS production by phorbol 12-myristate 13-acetate (PMA)-stimulated inflammatory cells. Moreover, the radical scavenging activities of both agents were examined by using a hypoxanthine-xanthine oxidase system and the stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). NADPH oxidase activity was determined in particulate (membrane) fractions prepared from PMA-stimulated RAW 264 x 7 cells, a macrophage-like cell line.

RESULTS

Both of these antifungal agents inhibited PMA-stimulated ROS production. However, only CPO significantly scavenged both ROS generated by the hypoxanthine-xanthine oxidase system and DPPH, and the scavenging activity of CPO seemed to act on ROS other than superoxide anions. Although KCZ inhibited PMA-stimulated ROS production, it did not show radical-scavenging activities. The inhibition of ROS production by KCZ is probably attributable to the inhibition of NADPH oxidase activity.

CONCLUSIONS

The mechanism of the inhibitory action of KCZ against PMA-stimulated ROS production is distinct from that of CPO. Knowledge of the inhibitory or scavenging effects of both antifungal agents on ROS released from inflammatory cells may be useful in developing a therapeutic strategy for dermatitis.

Effect of orally administered rolipram, a phosphodiesterase 4 inhibitor, on a mouse model of the dermatitis caused by 2,4,6-trinitro-1-chlorobenzene (TNCB)-repeated application

The purpose of this study was to evaluate the efficacy of rolipram, a phosphodiesterase (PDE) 4 inhibitor, in a mouse model of dermatitis induced by repeated application of 2,4,6-trinitro-1-chlorobenzene (TNCB). BALB/c mice were sensitized with 0.3% w/v TNCB applied to the ear on day -7, followed by application three times a week from day 0. Rolipram, prednisolone and cyclosporine A were administered orally once daily from day 0 to 21. Rolipram at a dose of 10 mg/kg/day significantly inhibited the ear thickness and the increase in cytokine levels and enzyme activity in the ear. Interleukin (IL)-4 production was markedly decreased in cervical lymph node cells from animals treated with rolipram at a dose of 10 mg/kg/day. Prednisolone and cyclosporine A significantly reduced ear thickness. These compounds significantly decreased the total cell and lymphocyte number of the cervical lymph nodes. Furthermore, prednisolone markedly suppressed body weight gain, and cyclosporine A significantly increased the serum total IgE concentration compared with that in the vehicle-treated control. Rolipram, unlike prednisolone and cyclosporine A, did not influence body weight and the total IgE concentration in the serum. The present results suggest that the PDE4 inhibitor is a promising oral medicine for the treatment of chronic skin inflammatory diseases.

Olopatadine hydrochloride suppresses the rebound phenomenon after discontinuation of treatment with a topical steroid in mice with chronic contact hypersensitivity

BACKGROUND

Olopatadine hydrochloride (olopatadine; Allelock) is one of the second-generation antihistamines that are treated for allergic disorders such as rhinitis, urticaria and eczema dermatitis. Olopatadine has recently been shown to have inhibitory effects on the chronic contact hypersensitivity induced by repeated application of oxazolone in mice. Although topical steroids have widely been prescribed for atopic dermatitis, a relapse often occurs within several days after discontinuation of their prolonged use.

OBJECTIVES

We investigated the possible efficacy of olopatadine against the relapse after discontinuation of prolonged use of topical prednisolone in the Balb/c mice with oxazolone-induced chronic contact hypersensitivity.

METHODS

Mice with the chronic contact hypersensitivity induced by repeated application of oxazolone were treated with olopatadine as a sequential therapeutic agent. The effects of olopatadine were quantified by measurements of ear-swelling, and levels of cytokines and histamine in the lesioned ear. Results Topical prednisolone (0.05 mg/ear/day) significantly inhibited the increases in ear swelling and production of IL-1beta, IL-4, IL-18, granulocyte-macrophage colony-stimulating factor (GM-CSF) and histamine. However, after discontinuation of the treatment with topical prednisolone, the inflammation relapsed and the IL-4 level exceeded the control one. The sequential treatment with olopatadine (10 mg/kg/day) after discontinuation of the treatment with topical prednisolone alone, or topical prednisolone with olopatadine, significantly inhibited the increases in ear swelling and levels of IL-1beta, IL-4, IL-18, GM-CSF, nerve growth factor and histamine.

CONCLUSIONS

These results indicate that olopatadine is an antihistamine agent having inhibitory activities against the rebound phenomenon following the discontinuation of topical steroid therapy. Olopatadine is thus expected to be a sequential therapeutic agent after discontinuation of the chronic treatment with a topical steroid.

Animal models for atopic dermatitis: are they relevant to human disease?

Over the last decade, animal models of atopic dermatitis (AD) have received increasing attention. They include NC/Nga mice, a hapten-induced mouse model, and transgenic and knockout mouse models. Although the pathogenesis of skin inflammation elicited in these models and that in AD are not quite the same, it is pertinent to ask what these animal models really tell us about the pathogenesis and possible therapies for the disease. NC/Nga mice may yield information relevant to the dissection of the crucial components of the pathophysiology of AD rather than the assessment of potentially therapeutic agents for its treatment. A hapten-induced mouse model created by repeated application of 2,4,6-trinitrochlorobenzene (TNCB) is a simple and reproducible one. This model offers several advantages over others: by changing hapten and the mouse strain used, various types of chronic inflammation, probably reflecting heterogeneity in clinical presentation of AD, can be induced; this model is also of enormous value in its high reproducibility as well as the ease of quantitative assessment by measuring ear thickness. Among various transgenic and knockout mouse models, the IL-18-transgenic mouse is one of the closest available mouse models of human AD, although the onset of the AD-like lesions in the IL-18-transgenic mice is such a late event. Although these mice all have significant disadvantages, it is important to review the current literature on the models in the hope that one may identify useful areas for investigation.

[Recent development of new drugs for the treatment of allergic diseases]

Due to the prevalence of allergic diseases such as bronchial asthma, allergic rhinoconjunctivitis and dermallergosis, efforts at the discovery of novel and effective medications for prevention and treatment of these conditions have been reinforced. Recently, it has been recognized that these allergic diseases are a chronic inflammatory disorder of the lower and upper airways and skin. In this article, we reviewed the recent development of the following new antiallergic therapies: anti-Th2 cytokine antibodies, decoy receptors, receptor antibodies, anti-IgE antibodies, anti-cell adhesion molecules antibodies, antisense oligonucleotides, keratinocyte modulators, inhibitors of phosphodiesterase 4, tachykinin receptor antagonists, and anti-histaminic drugs. Most of these new agents are aimed to inhibit various components of allergic inflammation. The future use of allergic disease therapies hold great promise and excitement.