Silibinin Regulates Gene Expression, Production and Secretion of Mucin from Cultured Airway Epithelial Cells
ABSTRACT We investigated whether silibinin significantly affects gene expression, production and secretion of mucin from cultured airway epithelial cells. Confluent NCI-H292 cells were pretreated with silibinin for 30 min and then stimulated with epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA) or TNF-α for 24 h. The MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The effect of silibinin on TNF-α-induced activation of NF-κB p65 was also examined. Confluent primary rat tracheal surface epithelial (RTSE) cells were pretreated with adenosine triphosphate (ATP) for 5 min and then treated for 30 min in the presence of silibinin to assess the effect on mucin secretion using ELISA. The results were as follows: (i) silibinin inhibited the expression of the MUC5AC mucin gene induced by EGF, PMA or TNF-α from NCI-H292 cells; (ii) silibinin also inhibited the production of MUC5AC mucin protein induced by the same inducers from NCI-H292 cells; (iii) silibinin inhibited the activation of NF-κB p65 by TNF-α in NCI-H292 cells; (iv) silibinin significantly decreased ATP-induced mucin secretion from cultured RTSE cells. This result suggests that silibinin can regulate gene expression, production and secretion of mucin by directly acting on airway epithelial cells. Copyright © 2012 John Wiley & Sons, Ltd.
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ABSTRACT: Deregulated mucin expression is a hallmark of several inflammatory and malignant pathologies. Emerging evidence suggests that, apart from biomarkers, these deregulated mucins are functional contributors to pathogenesis in inflammation and cancer. Both overexpression and downregulation of mucins in various organ systems is associated with pathobiology of inflammation and cancer. Restoration of mucin homeostasis has become an important goal for therapy and management of such disorders and has fueled the quest for selective mucomodulators. With improved understanding of mucin regulation and mechanistic insights into their pathobiological roles, there is optimism to find selective non-toxic agents capable of modulating mucin expression and function. Recently, natural compounds derived from dietary sources have drawn attention due to their anti-inflammatory and anti-oxidant properties and low toxicity. Considerable efforts have been directed towards evaluating dietary natural products as chemopreventive and therapeutic agents; identification, characterization and synthesis of their active compounds; and improving their delivery and bioavailability. We describe the current understanding of mucin regulation, rationale for targeting mucins with natural products and discuss some natural products that modulate mucin expression and functions. We further discuss the approaches and parameters that should guide future research to identify and evaluate selective natural mucomodulators for therapy.Cancer Treatment Reviews 01/2015; 41(3). DOI:10.1016/j.ctrv.2015.01.001 · 6.47 Impact Factor
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ABSTRACT: In the present study, we investigated whether aqueous extract of Liriope Tuber, ophiopogonin D and spicatoside A derived from Liriope Tuber affect basal or phorbol ester (phorbol 12-myristate 13-acetate, PMA)-induced airway mucin production and secretion from airway epithelial cells. Confluent NCI-H292 cells were treated with each agent for 24h (basal production) or pretreated with each agent for 30min and then stimulated with PMA for 24h (PMA-induced production and secretion), respectively. MUC5AC airway mucin production and secretion were measured by ELISA. The results were as follows: (1) aqueous extract of Liriope Tuber stimulated basal mucin production and did not inhibit but increased PMA-induced mucin production; (2) ophiopogonin D and spicatoside A stimulated basal mucin production and did not inhibit but increased PMA-induced mucin production; (3) two compounds increased PMA-induced mucin secretion. These results suggest that ophiopogonin D and spicatoside A can increase mucin production and secretion, by directly acting on airway epithelial cells and, at least in part, explain the traditional use of aqueous extract of Liriope Tuber as expectorants in diverse inflammatory pulmonary diseases.Phytomedicine: international journal of phytotherapy and phytopharmacology 09/2013; DOI:10.1016/j.phymed.2013.08.013 · 2.88 Impact Factor
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ABSTRACT: Abstract Purpose: Membrane-associated mucins (MAMs) play important roles in barrier function and tear stability, and their expression on the ocular surface is altered in dry eye disease. Rebamipide is a mucin secretagogue that promotes the production of mucin-like glycoproteins in human corneal epithelial (HCE) cells. However, the expression of MAMs on the corneal epithelia (MUC1, MUC4, MUC16), which is induced by rebamipide, is poorly understood. In this study, we investigated the effect of rebamipide on the regulation of MAM expression in HCE cells. Materials and Methods: MUC16, Ki67 and PCNA expression levels in HCE cells isolated at confluence and at 24 hours after confluence were examined by Western blotting to assess cell proliferation. HCE cells isolated at 24 hours after confluence were cultured in medium supplemented with 1-10 µM rebamipide or 0.3-30 nM of epidermal growth factor (EGF). Real-time PCR (RT-PCR) and Western blot analysis of MAMs were performed to evaluate the effect of rebamipide. Western blot analysis of cells treated with an EGF receptor inhibitor (AG1478) or MEK1/2 inhibitor (U0126) was performed to reveal the relationship between EGF receptor activation and rebamipide-induced MAM expression. Results: HCE cells isolated at 24 hours after confluence had lower cell proliferation activity and increased MUC16 expression compared with cells isolated at confluence. RT-PCR and Western blot analysis revealed that rebamipide increased MAM gene expression for 2 hours and protein expression for 24 hours in HCE cells. EGF inhibitor treatment led to reduced levels of all three MAMs that are normally induced by rebamipide, whereas EGF induced the expression of all three MAMs. Conclusions: We suggested that rebamipide increased MUC1, MUC4 and MUC16 expression levels through signals involved in EGF receptor activation in the human corneal epithelia. These data suggest that rebamipide may improve subjective symptoms of dry eye disease by upregulating MAM expression.Current eye research 09/2013; DOI:10.3109/02713683.2013.834939 · 1.66 Impact Factor