The Role Of Differential Expression Of Prostaglandin E2Receptors In The Pathogenesis Of CRSwNP In Active Smoking And Non-smoking Patients

Background and objective::Several studies have suggested that prostaglandin E2(PGE2) and E-prostanoid (EP) receptors play a role in the pathogenesis of chronic rhinosinusitis (CRS) in Caucasian populations. However, until now there was no report about EP receptor expression and their roles in the pathophysiology of CRS in Chinese patients. To investigate expression profiles of the four EP receptor subtypes, EP1, EP2, EP3and EP4receptors in different Chinese CRS patients with aspirin tolerance.Methods:Nasal biopsies were obtained from12controls,12chronic rhinosinusitis without nasal polyps (CRSsNP),12eosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP) and16noneosinophilic CRSwNP patients. Histopathologic characteristics were observed under light microscopy. Immunostaining was used to examine tissue localization of EP receptors. mRNA and protein expression of EP receptors were examined by means of quantitative RT-PCR and western blot respectively. Immunohistochemical staining of consecutive serial sections was conducted between EP receptor and eosinophil cationic protein (ECP).Results:Different types of CRS presented different histopathologic hallmarks. EP receptors were expressed mainly on epithelium, glands and infiltrating inflammatory cells in nasal tissue. In controls, CRSsNP and noneosinophilic CRSwNP patients, EP4mRNA level was higher than EP1, EP2and EP3receptors. EP2was down-expressed and EP1was up-expressed in eosinophilic CRSwNP patients. When comparing EP receptor expression between different groups, mRNA and protein of EP1receptor were significantly enhanced in eosinophilic CRSwNP, but EP2, EP3and EP4receptor did not show significant difference. The percentage of both EP1and ECP positive cells to total EP1-positive cells was47%(40～53%), and to total ECP-positive cells was50%(42～54%).Conclusion:EP receptor expression present different features in healthy subjects and different CRS. The up-regulated EPl receptors in eosinophilic CRSwNP might be associated with excessive infiltrations of eosinophils and other inflammatory cells. The accurate role of the four EP receptors in the pathogenesis of different CRS remains to be further explored. Background and Objective:The pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) remains unknown. Previous studies found that PGE2-EP involved in the pathogenesis of CRSwNP. The expression of EP receptor is regulated by various physiological and pathophysiological stimulus. Tobacco smoke is a risk factor in respiratory inflammation, whether it plays a significant role in the pathogenesis of CRSwNP remains unclear. However, the majority of the research suggested smoking may cause and aggravate inflammation in CRSwNP. We aim to compare the expression of EP1, EP2, EP3and EP4receptors in both groups, and to explore the relationship between smoking and the formation of CRSwNP.Methods:Nasal polyps samples were obtained from21Smoking CRSwNP (S-NP) and28Non-Smoking CRSwNP (N-NP). Histopathologic characteristics of both S-NP and N-NP groups were observed under optical microscope. Immunohistochemical staining was used to examine tissue localization of the four EP receptor subtypes. mRNA and protein expression of EP receptors were analyzed by quantitative RT-PCR and western blot respectively.Results:Histopathologic analysis showed that squamous metaplasia, goblet cell hyperplasia, neutrophil infiltration and interstitial fibrosis were more intense in S-NP group as compared with N-NP group. Immunohistochemical analysis showed that the expression localization of EP receptors in both group were similar. The rank orders of EP mRNA expression were EP4>EP3>EP1>>EP2in N-NP group, and EP3>EP1>EP4>>EP2in S-NP. Compared with N-NP group, mRNA and protein expression of EP2and EP4receptors, but not EP1and EP3receptor, were significantly down-regulated in S-NP group,Conclusion:Smoke exposure does not alter the tissue localization of EP receptors. Cigarette smoke might be involved in the formation and development of CRSwNP by down-regulating the expression of EP2and EP4receptors. Background and Objective:Studies have confirmed that expression of TNF-a, IL-6and other cytokines increased in nasal secretion or polyps tissue, which play an important pro-inflammatory role in the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). We previously found that reduced expression of EP4and EP2receptors in S-NP tissue potentially mediated target cell activation and involved in the development and progression of CRSwNP. However, whether smoking promots the airway and systemic inflammation in CRSwNP patients is unclear. In this study, we aim to compare the expression of TNF-a, IL-6in polyps tissue and serum between S-NP group and N-NP group, and to study whether the inflammatory mediators is correlated with smoking intensity.Methods:Nasal polyp samples and intravenous serum samples obtained from21S-NP (Smoking CRSwNP) and28N-NP (Non-Smoking CRSwNP). Smoking Index (SI) was calculated as the number of packets of smoking every day×years of smoking. ELISA (Enzyme-linked immunosorbent assay) was used to detect the levels of IL-6, TNF-a in polyps and serum of different groups. Spearmam test was used for correlation analysis with SI.Results:Compared with N-NP group, contents of TNF-a (P<0.05) and IL-6(P value-0.06) were increased in S-NP group. No significant difference in serum concentrations of TNF-α and IL-6were detected between N-NP and S-NP. Spearman correlation analysis showed TNF-a and IL-6levels were not correlated with SI. Conclusions:Active smoking may lead to the production of cytokines in nasal tissue but not lead to systematic inflammation, and the effect is independent of smoking intensity. Objective:1. To compare the expression of EP1, EP2, EP3and EP4receptors of peripheral blood mononuclear cell (PBMC) in active smoking (S-NP) and non-smoking CRSwNP (N-NP) groups.2. To study the effect of cigarette smoke extract (CSE) on the EP receptors expression and TNF-a and IL-6release in human peripheral blood mononuclear cell (PBMC).Methods:1. PBMCs were obtained using Ficoll density gradient centrifugation method from21S-NP and28N-NP. mRNA and protein expression of EP receptors were tested by quantitative RT-PCR and western blot respectively.2. PBMCs from6N-NP patients were stimulated with different concentration of CSE (0%、0.1%、1%、10%). After24hours, mRNA and protein expression of EP receptors were analyzed by quantitative RT-PCR and western blot respectively. Elisa technique was used to detect TNF-a and IL-6concentrations in supernatant.Results:1. The rank orders of EP mRNA expression intensity were EP4>>EP2>>EP1>EP3in both N-NP and S-NP groups. Compared with N-NP group, mRNA and protein expression of all EP receptors were not significantly different.2. Compared with the controls, EP1and EP3expression of PBMC was significantly increased after CSE stimulation for24hours. By contrast, EP2and EP4expression of PBMC was significantly decreased after CSE stimulation.3. After stimulating to PBMC with different concentrations of CSE (0.1%,1%,10%), the levels of TNF-a and IL-6in supernatant increased concentration-dependently, compared with the control group. And the1%and10%CSE groups showed statistical significance compared with controls.Conclusions:Altered expression of EP receptors between active smoking and non-smoking CRSwNP groups maybe confined to the nasal mucosa. CSE stimuli probably facilitate the initiation and progress of inflammation by upregulating EP1, EP3receptors expression and down-regulating EP2, EP4receptors expression in human PBMC.