Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of macrolide therapy in chronic sinusitis patients is unclear. The authors studied the effect of macrolides on interleukin (IL)-8 secretion from cultured human nasal epithelial cells. Epithelial cells harvested from the nasal polyps of patients with chronic sinusitis were primary-cultured, and secreted IL-8 in culture media was measured by enzyme immunoassay. The cells secreted considerable amounts of IL-8 constitutively and in response to lipopolysaccharide. The secretion was significantly inhibited by 10(-5) M of erythromycin, clarithromycin, roxithromycin, and josamycin. 10(-6) M erythromycin still showed the inhibitory effect, whereas the same concentration of josamycin did not. These results indicate that macrolide antibiotics may act as an immunomodulator to reduce IL-8 in inflammatory sites and, at least partially, account for the clinically discrepant effects between 14- and 16-membered ring macrolides in long-term low-dose therapy for chronic sinusitis.
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PMID:Inhibitory effect of macrolides on interleukin-8 secretion from cultured human nasal epithelial cells. 939 83

A study was performed to elucidate the action of long-term macrolide therapy in chronic sinusitis. Clarithromycin (CAM) was administered orally once daily for 14 days. On the last 3 days, an endotoxin, lipopolysaccharide (LPS) was instilled intranasally. The extent of DNA synthesis acceleration was studied in both controls and pretreated animals by counting the number of 5-bromo-2'-deoxyuridine (BrdU)-labeled cells in the nasal transitional epithelium. Six hours after the final intranasal instillation of LPS, the number of BrdU-positive cells was significantly higher than control. Pretreatment with CAM for 2 weeks significantly inhibited this increase. Because similar results were obtained in neutrophil-depleted rats, LPS apparently promotes proliferation of the nasal epithelium in the absence of neutrophils: CAM-suppressed epithelial proliferation independently of the neutrophil count. Our results suggest that CAM inhibits LPS-induced increased rates of DNA synthesis by directly affecting the nasal epithelium. The mechanism by which macrolide therapy alleviates the signs and symptoms of chronic sinusitis might therefore involve suppression of inflammatory processes in the nasal and paranasal sinus epithelium.
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PMID:Clarithromycin suppresses proliferation of rat nasal epithelium exposed to endotoxin. 988 3

Although several studies have demonstrated that low-dose, long-term 14-member macrolides (erythromycin (EM), roxithromycin (RXM), clarithromycin (CAM)) are effective in the treatment of chronic airway diseases like chronic sinusitis and diffuse panbronchiolitis (DPB), the mechanism of action of these drugs is not yet clear. Both these airway diseases are associated with an increase in the proliferation of fibroblasts. Moreover, fibroblasts are also an important source of proinflammatory cytokines such as interleukin-8 (IL-8), that play an important role in the pathogenesis of nasal polyps. Therefore, using primary fibroblast lines derived from nasal polyps, we investigated the effect of RXM on the synthesis of IL-8 and proliferation of nasal polyp fibroblasts (NPF). These fibroblasts were either treated with lipopolysaccharide (LPS) and RXM for 24 h, or pre-incubated with RXM for 24 h and then treated with LPS and RXM for 24 h. The level of IL-8 mRNA in NPF was analysed by reverse transcriptase-polymerase chain (RT-PCR) and the level of IL-8 in culture supernatants was measured by ELISA. Next, the proliferative capacity of NPF after treatment with RXM was analysed by cell counting and 3H-thymidine uptake. RXM had no effect on LPS-induced IL-8 synthesis by NPF. On the other hand, RXM suppressed the proliferation of NPF in a dose-dependent manner. These findings suggest that, although RXM cannot directly inhibit the synthesis of IL-8, it probably reduces IL-8 production by inhibiting the proliferation of NPF.
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PMID:Effect of roxithromycin on IL-8 synthesis and proliferation of nasal polyp fibroblasts. 1009 66

Erythromycin and other macrolides are effective for the treatment of chronic inflammatory airway diseases such as diffuse panbronchiolitis (DPB) and chronic sinusitis. The effect of macrolides in DPB is suggested to be anti-inflammatory rather than antibacterial. We investigated the effects of clarithromycin on interleukin-8 (IL-8) production using human peripheral monocytes and the human monocytic leukaemia cell line, THP-1. Bacterial extracts from Escherichia coli, Pseudomonas aeruginosa and Helicobacter pylori, as well as E. coli-derived lipopolysaccharide (LPS), induced IL-8 production. Clarithromycin suppressed this production in a dose-dependent manner in both monocytes and THP-1 cells (49.3-75.0% inhibition at 10 mg/L). A luciferase reporter gene assay with plasmids containing a serially deleted IL-8 promoter fragment showed that both the activator protein-1 (AP-1) and/or the nuclear factor-kappa B (NF-kapp aB) binding sequences were responsible for the LPS and clarithromycin responsiveness of the IL-8 promoter. Consistently, in an electromobility shift assay, LPS increased the specific binding of both AP-1 and NF-kappaB, whereas clarithromycin suppressed it. Moreover, LPS and clarithromycin regulated three other promoters that have either the NF-kappa B or the AP-1 binding sequences: two synthetic (pAP-1-Luc and pNF-kappa B-Luc) and one naturally occurring (ELAM-Luc). Our results indicate that clarithromycin modified inflammation by sup-pressing IL-8 production and that clarithromycin may affect the expression of other genes through AP-1 and NF-kappa B. In addition to treatment of airway diseases, the anti-inflammatory effect of macrolides may be beneficial for the treatment of other inflammatory diseases such as chronic gastritis caused by H. pylori.
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PMID:Clarithromycin suppresses lipopolysaccharide-induced interleukin-8 production by human monocytes through AP-1 and NF-kappa B transcription factors. 1200 67

Chronic rhinosinusitis (CRS) is a well-known disease encountered in the department of otorhinolaryngology, yet little is known about its pathogenesis. Autophagy, a lysosome-dependent degradation process, has been reported to be involved in the process of many chronic inflammatory diseases. Here we tried to evaluate the function of autophagy in CRS as well as explore the related mechanisms. We first stained light chain 3B (LC3B) with immunohistochemistry in uncinate tissues (UT) from patients with and without CRS and found that its expression was up-regulated in CRS patients. Then, Human Nasal Epithelial Cells (HNEpC) were treated with lipopolysaccharide (LPS), one of the most common pathogenic elements in CRS, and we found that autophagy was induced in a dose- and time-dependent manner. This is supported by a rise in the expression of light chain 3B-II (LC3B-II), accumulation of GFP-LC3 vesicles, as well as decreased p62 expression. Furthermore, we found that LPS promoted AMPK phosphorylation and inactived mTOR, while AMPK inhibition by compound C significantly attenuated LPS-induced autophagy. Besides, treatment of HNEpC with LPS increased the amount of Toll-like receptor 4 (TLR4) while inhibiting TLR4 by Polymyxin B (PMB) declined autophagy caused by LPS. Taken together, our study first demonstrated that LPS caused autophagy in HNEpC, and this process was AMPK-mTOR dependent. These data suggested the relationship between LPS and autophagy in the pathogenesis of CRS.
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PMID:Lipopolysaccharide induces autophagy by targeting the AMPK-mTOR pathway in Human Nasal Epithelial Cells. 2922 53

Chronic rhinosinusitis (CRS) is a frequent disease with high social impact and multifactorial pathogenesis. Recently, the bitter taste receptor TAS2R38 has been described to play a role in upper airway innate mucosal defense. The aim was to determine the localization and expression of the TAS2R38 in the selected cell lines and tissue collected from patient suffered from CRS as well as to correlate the results with clinical data. Moreover, the purpose was the estimation of the TAS2R38 distribution changes during acute and CRS. Forty-two patients undergoing nasal surgery were enrolled in the study. The TAS2R38 expression was assessed in the collected tissues using immunohistochemistry and immunocytochemistry methods. The western blot analysis was performed on human cell lines HeLa, MCF7, MDA-MB-231 to assess the location of the TAS2R38 protein. Moreover, the HeLa cell line was used as a model of acute inflammation induces by lipopolysaccharide. Immunohistochemistry analysis displayed a statistically significant difference of TAS2R38 level in the patients with CRS compared to healthy control and was different in CRS with and without nasal polyps. The results showed the abundance of TAS2R38 receptor in the cell nucleus in patients with CRS and cell lines. The variance in TAS2R38 receptor expression in two CRS types suggests their different pathogenesis. The first time in literature, we confirmed the presence of plasma membrane TAS2R38 receptor in the cell nuclei in CRS as well as in cell lines, what strongly suggests the different than membrane TAS2R38 function.
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PMID:The expression of bitter taste receptor TAS2R38 in patients with chronic rhinosinusitis. 3290 59