title: Andrographolide antagonizes cigarette smoke extract-induced inflammatory response and oxidative stress in human alveolar epithelial A549 cells through induction of microRNA-218.
abstract: Andrographolide is a major bioactive labdane diterpenoid isolated from Andrographis paniculata and has protective effects against cigarette smoke (CS)-induced lung injury. This study was done to determine whether such protective effects were mediated through modulation of microRNA (miR)-218 expression. Therefore, we exposed human alveolar epithelial A549 cells to cigarette smoke extract (CSE) with or without andrographolide pretreatment and measured the level of glutathione, nuclear factor-kappaB (NF-κB) activation, proinflammatory cytokine production, and miR-218 expression. We found that andrographolide pretreatment significantly restored the glutathione level in CSE-exposed A549 cells, coupled with reduced inhibitor κB (IκB)-α phosphorylation and p65 nuclear translocation and interleukin (IL)-8 and IL-6 secretion. The miR-218 expression was significantly upregulated by andrographolide pretreatment. To determine the biological role of miR-218, we overexpressed and downregulated its expression using miR-218 mimic and anti-miR-218 inhibitor, respectively. We observed that miR-218 overexpression led to a marked reduction in IκB-α phosphorylation, p65 nuclear accumulation, and NF-κB-dependent transcriptional activity in CSE-treated A549 cells. In contrast, miR-218 silencing enhanced IκB-α phosphorylation and p65 nuclear accumulation in cells with andrographolide pretreatment and reversed andrographolide-mediated reduction of IL-6 and IL-8 production. In addition, depletion of miR-218 significantly reversed the upregulation of glutathione levels in A549 cells by andrographolide. Taken together, our results demonstrate that andrographolide mitigates CSE-induced inflammatory response in A549 cells, largely through inhibition of NF-κB activation via upregulation of miR-218, and thus has preventive benefits in CS-induced inflammatory lung diseases.
authors.affiliation: 1Department of Cardio-thoracic Surgery, First Affiliated Hospital of Chinese PLA General Hospital, Beijing, China.
authors.forename: Ying-jie
authors.initials: YJ
authors.lastname: Li
authors.forename: Chang-hai
authors.initials: CH
authors.lastname: Yu
authors.forename: Jing-bo
authors.initials: JB
authors.lastname: Li
authors.forename: Xi-ya
authors.initials: XY
authors.lastname: Wu
mesh_terms: D056809:Alveolar Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D002460:Cell Line; D004224:Diterpenes / Q000494:pharmacology*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D020868:Gene Silencing; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D018384:Oxidative Stress / Q000187:drug effects; D012906:Smoke / Q000009:adverse effects*; D014026:Nicotiana / Q000009:adverse effects*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C508606:CXCL8 protein, human; D004224:Diterpenes; D004365:Drugs, Chinese Herbal; D020672:I-kappa B Proteins; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; C547471:MIRN218 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D012906:Smoke; D000072000:NF-KappaB Inhibitor alpha; C030419:andrographolide; D005978:Glutathione