The Expression And Mechanisms Of Sirtuins In Chronic Rhinosinusits With Nasal Polyps

BackgroundDespite major advances in understanding the molecular pathogenesis and mechanism of chronic rhinosinusitis with nasal polyps (CRSwNP), yet whether other regulatory events required to the network of mediators involved in the processed of CRSwNP are less well understood. Release of various pro-inflammatory cytokines including IL-1β, IL-5, IL-6, IL-17, and HMGB1,and excessive reactive oxygen species (ROS) production are considered to participate in the pathogenesis of CRSwNP. Accumulating evidences suggest the Sirtuins family members (Sirtl-Sirt7) have protective effects against aging,inflammation, cell death and oxidative stress in pathological progresses of various acute or chronic inflammatory diseases, immune disorders and metabolic diseases. Our previous studies have initially demonstrated that Sirtl and Sirt6 modulated the lipopolysaccharide (LPS)-induced translocation and release of HMGB1 in nasal epithelial cells However, the Sirtuins signaling in nasal polyps remains controversial. The therapeutic efficacy of CRSwNP is still needed to be improved. Therefore, the specific molecules mechanism associated with inflammation and oxidative stress and in-depth study of its regulation mechanisms is required.ObjectiveThe aim of our present study is to investigate the expression of Sirtuins and related factors in CRSwNP, and molecule mechanisms of Sirtuins in the protective effects that associated with inflammation and oxidative stress in nasal epithelial cells.MethodsNasal polyps samples were obtained from 52 patients with CRSwNP and normal nasal mucosa samples from 15 non-CRS patients were used as controls. Expression levels of Sirtuins, inflammatory cytokines (IL-1β, IL5, IL-8, IL-10, IL-17 and HMGB1),oxidative stress related antioxidant enzymes GPX4 was investigated by real-time PCR,western blotting and immunohistochemistry assay. The primary human nasal epithelial(HNE) cells from nasal polyps were stimulated with LPS. siRNA technique was utilized to knockdown Sirtl expression in HNE cells. Effects of knockdown and overexpressed Sirtl on the proliferation were examined by MTT. The differentiation of HNE cells was observed by immunofluorescence assay and flow cytometry (FACS). Cell death was determined by Annexin V/7AAD staining using FACS. ROS production was assessed by BODIPY staining using FACS.ResultsIn the present study, we identified both mRNA and protein expression levels of Sirtl, Sirt3 and Sirt6 to be lower in CRSwNP tissue compared to normal nasal mucosa.Protein levels of HMGB1 and Nrf2, as well as NF-kB, p-IkB was upregulated in CRSwNP. However, GPX4 and p-STAT was decreased in CRSwNP. Moreover, GPX4 mRNA expression was negatively correlated with IL-1(3, IL-5, IL-8, and IL-17 mRNA expression. In vitro, Sirtl was introduced into human nasal epithelial (HNE) cells and Sirtl was knockdown by RNA interference. We found that Sirtl knockdown dramatically inhibited cell growth and induced cell death. Sirtl also affected cilia differentiation and upregulated CK14 expression levels in Sirtl knockdown HNE cells.Further, Sirtl modulated the oxidative stress of HNE cells through regulating GPX4,NF-kB and STAT pathway. Additionally, Sirtl knockdown sensitized HNE cells for LPS induced ROS accumulation and ferroptosis.ConclusionsThese findings revealed the alternative expressions of Sirtuins in nasal polyps, and elucidated a crucial role of Sirtl as a protective factor against inflammation and oxidative stress in nasal epithelial cells, providing an insight into the mechanisms of epigenetic modulation of immune responses. Sirtl pathway might be a potential therapeutic target for controlling the process of chroni rhinisinusitis with nasal polyps.