1,8-cineol inhibits the Wnt/ß-catenin signaling pathway through GSK-3 dephosphorylation in nasal polyps of chronic rhinosinusitis patients.

Chronic rhinosinusitis with nasal polyps (CRSwNP) represents a benign neoplasm of the nasal mucosa, which leads to a decreased breathing capacity and reduced olfaction. The pathogenesis and the molecular mechanisms driving nasal polyps are not very well known. GSK-3 is involved in the regulation of various biosynthetic pathways and various kinases are able to regulate the GSK-3. Therefore, we investigated the effect of the monoterpene oxide 1,8-cineol on the regulation of the Wnt/ß-catenin signaling pathway with its central regulator protein GSK-3 in vitro. We determined GSK-3 expression and phosphorylation as well as the expression of negative regulators (Akt and SGK) and downstream activation of ß-catenin in nasal polyps of patients with CRSwNP by immunohistochemistry and Western blot experiments. In this study we demonstrated for the first time, that 1,8-cineol acts as a potential inhibitor of the Wnt/ß-catenin signaling pathway, by affecting the inhibitory phosphorylation of GSK-3, which is the key regulator of the ß-catenin activity. Our data provide novel insights in the regulatory networks responsible for the progression of CRSwNP and furthermore represent a new mechanism of 1,8-cineol activity, which may lead to novel treatment approaches to this natural drug.

Increased phosphorylation of eNOS in nasal polyps of chronic rhinosinusitis patients can be diminished by 1,8-cineol.

INTRODUCTION: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a significant health problem, but the pathogenesis remains unclear to date. Nitric oxide (NO) has known airway modulating functions. Therefore, we investigated nitric oxide production to determine the role of eNOS in nasal polyps, with additional analysis of the effect of the monoterpene oxide 1,8-cineol on the possible regulation of eNOS signaling and thus NO production. METHODS: We determined eNOS expression, as well as regulatory and effector proteins like NOSTRIN and CASP8, using whole genome microarray, immunohistochemistry and western blot. To evaluate the influence of 1,8-cineol on eNOS signaling, we examined tissue samples of nasal polyps of patients with CRSwNP incubated with 100 µM 1,8-cineol using quantitative real-time PCR, western blot and phosphorylation arrays. RESULTS: Microarray analysis revealed an increased gene expression of eNOS (1.40-fold) as well as a decreased gene expression of NOSTRIN (0.53-fold) and CASP8 (0.44-fold) in nasal polyps. At the protein level, we detected 2.3-fold higher protein expression of eNOS and significant higher phosphorylation levels of eNOS in nasal polyps (19.7-fold, p ≤ 0.001) compared to inferior turbinates. Additionally, 1,8-cineol did not influence NOSTRIN and CASP8, but decreased the eNOS phosphorylation significantly (p ≤ 0.05). DISCUSSION: Our study demonstrated for the first time that nasal polyps exhibit an increased phosphorylation of eNOS, which could be important for vascular permeability and the associated edema and elevated inflammation. Additionally, we detected that 1,8-cineol affects the eNOS phosphorylation significantly and thus its activation. This could be important to handle the elevated inflammation and edema formation by regulating the vascular permeability.

Subtyping of polyposis nasi: phenotypes, endotypes and comorbidities.

BACKGROUND: Chronic rhinosinusitis (CRS) is a heterogeneous, multifactorial inflammatory disease of the nasal and paranasal mucosa. It has not been possible to date to develop an internationally standardized, uniform classification for this disorder. A phenotype classification according to CRS with (CRSwNP) and without polyposis (CRSsNP) is usually made. However, a large number of studies have shown that there are also different endotypes of CRS within these phenotypes, with different pathophysiologies of chronic inflammation of the nasal mucosa. This review describes the central immunological processes in nasal polyps, as well as the impact of related diseases on the inflammatory profile of nasal polyps. MATERIALS AND METHODS: The current knowledge on the immunological and molecular processes of CRS, in particular CRSwNP and its classification into specific endotypes, was put together by means of a structured literature search in Medline, PubMed, the national and international guideline registers, and the Cochrane Library. RESULTS: Based on the current literature, the different immunological processes in CRS and nasal polyps were elaborated and a graphical representation in the form of an immunological network developed. In addition, different inflammatory profiles can be found in CRSwNP depending on related diseases, such as bronchial asthma, cystic fibrosis (CF), or NASID-Exacerbated Respiratory Disease (N­ERD). CONCLUSION: The identification of different endotypes of CRSwNP may help to improve diagnostics and develop novel individual treatment approaches in CRSwNP.

Neuronal Differentiation Capability of Nasal Polyps of Chronic Rhinosinusitis.

Chronic rhinosinusitis with nasal polyps is considered a subgroup of chronic rhinosinusitis and a significant health problem, but the pathogenesis remains unclear to date. Therefore, we investigated the stemness to determine the role of stem cells in nasal polyps, with additional analysis of the neuronal differentiation potential of nasal polyp cells. We determined gene and protein expression profiles of stem cells in nasal polyp tissues, using whole genome microarray, quantitative real-time PCR (qPCR), immunohistochemistry, and flow cytometry. To evaluate the neuronal differentiation potential of nasal polyp cells, we used an efficient xenogeneic co-culture model with unsliced adult rat brain biopsies, followed by qPCR, immunohistochemistry, and growth factor antibody arrays. During gene expression analysis and immunohistochemistry, we were able to detect different stem cell markers, like Oct-4, Sox2, Klf4, c-Myc, ABCG2, Nanog, CD133, and Nestin, which confirmed the existence of stem cell like cells within nasal polyps. In addition, co-culture experiments give evidence for a guided differentiation into the neuronal lineage by overexpression of Nestin, Neurofilament, and GM-CSF. Our study demonstrated the expression of stem cell-related markers in nasal polyps. Furthermore, we characterized, for the first time, the stemness and neuronal differentiation potential of nasal polyp cells. These results gave new insights into the pathogenesis of nasal polyps and its therapeutic effectiveness could represent a promising strategy in the future.