Search

Eczema is a complex chronic inflammatory skin disease impacted by environmental factors, infections, immune disorders, and deficiencies in skin barrier function. Shi Zhen Tea (SZT), derived from traditional Chinese medicine Xiao-Feng-San, has shown to be an effective integrative therapy for treating skin lesions, itching, and sleeping loss, and it facilitates reduction of topical steroid and antihistamine use in pediatric and adult patients with severe eczema. Yet, its active compounds and therapeutic mechanisms have not been elucidated. In this study, we sought to investigate the active compounds and molecular mechanisms of SZT in treating eczema using systems pharmacology and in silico docking analysis. SZT is composed of 4 medicinal herbs, Baizhu (Atractylodis macrocephalae rhizome), Jingjie (Schizonepetae herba), Kushen (Sophorae flavescentis radix), and Niubangzi (Arctii fructus). We first identified 51 active compounds from SZT and their 81 potential molecular targets by high-throughput computational analysis, from which we identified 4 major pathways including Th17 cell differentiation, metabolic pathways, pathways in cancer, and the PI3K-Akt signaling pathway. Through network analysis of the compound-target pathway, we identified hub molecular targets within these pathways including carbonic anhydrase II (CA2), peroxisome proliferator activated receptor γ (PPAR γ), retinoid X receptor α (RXRA), and vitamin D receptor (VDR). We further identified top 5 compounds including cynarine, stigmasterin, kushenol, β-sitosterol, and (24S)-24-propylcholesta-5-ene-3β-ol as putative key active compounds on the basis of their molecular docking scores with identified hub target proteins. Our study provides an insight into the therapeutic mechanism underlying multiscale benefits of SZT for eczema and paves the way for developing new and potentially more effective eczema therapies.

The effect of thrombin receptor activation on monocyte conformation was evaluated using the human monocyte cell line, THP-1, and the thrombin mimetic peptide, Trap-14. Treatment of THP-1 cells with Trap-14 induced rapid rounding of ameboid cells adherent to fibronectin-coated slides, whereas cell rounding was abrogated in the presence of the nitric oxide synthase inhibitor, NG-nitro-l-arginine or the endothelin B receptor antagonist, BQ-788. Endothelin-1 (ET-1) levels in the culture supernatant increased markedly within minutes of Trap-14 exposure with a concomitant loss in cellular ET-1 immunoreactivity. Importantly, loss of ET-1 immunoreactivity was blocked by pretreatment with the vesicle translocation inhibitor, nocodazole. Trap-14 potently induced the release of NO from THP-1 cells, whereas NO release was ablated by preincubation with BQ-788. These data demonstrate that thrombin receptor activation may inhibit cellular spreading as a result of autocrine ET-1 release and subsequent endothelin B receptor-dependent NO production, and suggest that initial exposure of inflammatory cells to thrombin may limit cellular activation and recruitment.

The effect of agonists of the known protease activated receptors (PAR), the thrombin and the PAR-2 receptors, on vasoactive mediator release and vascular tone were studied using rings of rat aorta. Stimulation of aortic rings with the thrombin receptor agonist, Trap-14, or the PAR-2 agonist, SLIGRL, resulted in a rapid release of nitric oxide. Trap-14 and SLIGRL-induced nitric oxide release was reduced by pre-treatment with BQ-788, an ET B endothelin receptor-specific antagonist. Consistent with a role for endothelin-1 receptor activation in Trap-14 and SLIGRL-induced nitric oxide release, endothelin-1 levels were increased significantly following 5 min treatment of aortic rings with Trap-14 or SLIGRL. Cumulative addition of Trap-14 to aortic rings denuded of endothelium resulted in dose-dependent contraction with an EC 50 value of 23 ± 5 μM, whereas SLIGRL addition failed to induce aortic contraction. These data suggest that the known protease activated receptors are functionally coupled to nitric oxide release. In addition, the thrombin receptor appears to modulate both vasodilator and contractile responses, whereas the PAR-2 receptor is linked only to vasodilation.

Crystalline silica stimulates macrophages in vitro to release interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and nitric oxide (NO) and induces apoptosis of macrophages. Because the fibrogenic potential of a particulate paralleled its ability to induce apoptosis in macrophages, we investigated the underlying mechanisms by which IL-1beta and NO mediate apoptosis and inflammation in murine silicosis. First, we demonstrated that silica induced NO production and apoptosis in vitro using the IC-21 macrophage cell line. Both NO release and apoptosis could be inhibited by neutralizing anti-IL-1beta antibody or the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine-methyl ester (L-NAME), demonstrating the requirement for IL-1beta-mediated NO release in silica-induced apoptosis. We exposed IL-1beta knockout (IL-1beta(-/-)) mice, inducible NOS knockout (iNOS(-/-)) mice, and wild-type mice to 250 mg/m(3) silica for 5 h/d for 10 d using an inhalation chamber. Exposure of wild-type mice to silica resulted in lung inflammation, apoptosis, and significantly larger and more numerous silicotic lesions than in IL-1beta(-/-) mice over a 12-wk course. We also exposed iNOS(-/-) mice via inhalation in the same protocol and compared with wild-type mice and demonstrated that iNOS(-/-) mice had significantly reduced apoptosis and inflammation. These results demonstrated an association between apoptosis and inflammation in murine silicosis and support a potential role for IL-1beta-dependent NO-mediated apoptosis in the evolution of silicosis.