Impaired local Vitamin D3 metabolism contributes to IL-36g overproduction in epithelial cells in chronic rhinosinusitis with nasal polyps.

BACKGROUND: Vitamin D (VD) possesses immunomodulatory properties, but its role in chronic rhinosinusitis with nasal polyps (CRSwNP) remains poorly studied. Herein, we aim to explore the regulation and function of VD3 in CRSwNP. METHODS: 25-hydroxyvitamin D3 (25VD3) levels in serum and tissue lysates were detected by ELISA. The expression of VD receptor (VDR) and cytochrome P450 family 27 subfamily B member 1 (CYP27B1), the enzyme that converts 25VD3 to the active 1,25-hydroxyvitamin D3 (1,25VD3), and their expression regulation in human nasal epithelial cells (HNECs) were studied by RT-PCR, western blotting, immunofluorescence, and flow cytometry. RNA sequencing was performed to identify genes regulated by 1,25VD3 in HNECs. HNECs and polyp tissue explants were treated with 1,25VD3, 25VD3, and dexamethasone. RESULTS: 25VD3 levels in serum and nasal tissue lysates were decreased in patients with eosinophilic and noneosinophilic CRSwNP than control subjects. The expression of VDR and CYP27B1 were reduced in eosinophilic and noneosinophilic CRSwNP, particularly in nasal epithelial cells. VDR and CYP27B1 expression in HNECs were downregulated by interferon y and poly (I:C). Polyp-derived epithelial cells demonstrated an impaired ability to convert 25VD3 to 1,25VD3 than control tissues. 1,25VD3 and 25VD3 suppressed IL-36y production in HNECs and polyp tissues, and the effect of 25VD3 was abolished by siCYP27B1 treatment. Tissue 25VD3 levels negatively correlated with IL-36y expression and neutrophilic inflammation in CRSwNP. CONCLUSION: Reduced systemic 25VD3 level, local 1,25VD3 generation and VDR expression result in impaired VD3 signaling activation in nasal epithelial cells, thereby exaggerating IL-36y production and neutrophilic inflammation in CRSwNP.

Interferon-γ-induced insufficient autophagy contributes to p62-dependent apoptosis of epithelial cells in chronic rhinosinusitis with nasal polyps.

BACKGROUND: Autophagy is a lysosomal degradation pathway that is essential for cell survival, differentiation, and homeostasis. This study aimed to investigate the contribution of autophagy to the pathogenesis of CRS with nasal polyps (CRSwNP). METHODS: The expression of autophagic proteins [microtubule-associated protein 1 light chain 3B (LC3B)-II, autophagy-related proteins (Atg), and Beclin 1], substrate proteins (p62 and ubiquitinated proteins), and apoptotic signaling molecules [cysteine-aspartic protease-3 and cysteine-aspartic protease-8, and poly-ADP-ribose polymerase] in the sinonasal mucosa and nasal epithelial cells (NECs) was detected by immunohistochemistry and Western blotting. Autophagic vacuoles were observed with transmission electron microscopy. BEAS-2B cells and NECs were treated with rapamycin, bafilomycin A1, or various cytokines. In some experiments, cultured NECs were transfected with small interfering RNA targeting p62 (sip62) or Atg5 (siAtg5). Cultured cells were analyzed with Western blotting and flow cytometry. RESULTS: Although autophagic protein expression and autophagic vacuole formation were increased in both eosinophilic and noneosinophilic CRSwNP, particularly in NECs, there was also an up-regulation of substrate proteins and apoptotic signaling molecules. IFN-γ, but not IL-4, IL-13, or IL-17A, simultaneously enhanced LC3B-II and p62 levels as well as cell apoptosis in BEAS-2B cells and/or normal NECs. Bafilomycin A1 up-regulated the levels of LC3B-II and p62 in polyp NECs and IFN-γ-treated normal NECs. IFN-γ-induced apoptosis of normal NECs was exaggerated by bafilomycin A1 and siAtg5. Sip62 suppressed apoptosis of polyp NECs and IFN-γ-treated NECs. IFN-γ protein levels were increased in both eosinophilic and noneosinophilic CRSwNP. CONCLUSIONS: IFN-γ induces activated but insufficient autophagy and thus contributes to a degree to p62-dependent apoptosis of NECs in CRSwNP.

CD8(+) T cells with distinct cytokine-producing features and low cytotoxic activity in eosinophilic and non-eosinophilic chronic rhinosinusitis with nasal polyps.

BACKGROUND: CD8(+) T cells are important effectors of cell-mediated immunity; however, their contribution to the pathogenesis of CRS is unclear. OBJECTIVE: This study aimed to characterize the cytokine-producing features and cytotoxic activity of CD8(+) T cells, and their correlation with inflammation patterns in CRS with nasal polyps. METHODS: The expression of IFN-γ, IL-4, IL-5, IL-17A, forkhead box P3 (FOXP3), perforin, and granzyme B in CD8(+) T cells was studied by means of flow cytometry, immunohistochemistry, and immunofluorescence. The expression of CD8(+) T-cell subset relevant chemokines and chemokine receptors was detected by means of real-time RT-PCR or ELISA. The cytotoxic activity of sorted CD8(+) T cells was defined by anti-CD3-redirected killing assay. RESULTS: Compared with controls, elevated percentages of total CD8(+) T cells and cytotoxic T lymphocyte (Tc) 1 (IFN-γ(+) ), Tc2 (IL-4(+) ), and Tc17 (IL-17A(+) ) cell subset, and decreased percentages of FOXP3(+) CD8(+) regulatory T cells, were found in both eosinophilic and non-eosinophilic polyps with a Tc2-skewed and Tc1/Tc17-dominated response in eosinophilic and non-eosinophilic polyps, respectively. Nasal CD8(+) T cells were found to produce similar or even higher levels of IFN-γ and IL-4 compared with CD4(+) T cells. Tc1 and Tc17, and Tc2 (IL-4(+) and IL-5(+) ) cell subset percentages positively correlated with neutrophil and eosinophil counts in sinonasal mucosa, respectively. Strikingly, the expression of perforin and granzyme B and cytotoxic activity were significantly reduced in nasal CD8(+) T cells compared with their counterparts in peripheral blood. The expression of CXCL16, CCL17, and CCL20 positively correlated with Tc1, Tc2, and Tc17 cell subset number in sinonasal mucosa, respectively. CONCLUSION AND CLINICAL RELEVANCE: CD8(+) T cells have low cytotoxic activity; nevertheless, they are a significant and previously underappreciated source of inflammatory cytokine production in polyps. Different Tc cell subset domination may contribute to distinctly biased granulocyte inflammation in eosinophilic and non-eosinophilic polyps.

Cloning and sequencing of the genes downstream of the wbf gene cluster of Vibrio cholerae serogroup O139 and analysis of the junction genes in other serogroups.

The DNA sequence of the O-antigen biosynthesis cluster (wbf) of a recently emergent pathogen, Vibrio cholerae serogroup O139, has been determined. Here we report the sequence of the genes downstream of the O139 wbfX gene and analysis of the genes flanking the wbf gene cluster in other serogroups. The gene downstream of wbfX, designated rjg (right junction gene), is predicted to be not required for O-antigen biosynthesis but appears to be a hot spot for DNA rearrangements. Several variants of the rjg gene (three different insertions and a deletion) have been found in other serogroups. DNA dot blot analysis of 106 V. cholerae strains showed the presence of the left and right junction genes, gmhD and rjg, respectively, in all strains. Further, these genes mapped to a single I-CeuI fragment in all 21 strains analyzed by pulsed-field gel electrophoresis, indicating a close linkage. The insertion sequence element IS1358, found in both O1 and O139 wb* regions, is present in 61% of the strains tested; interestingly, where present, it is predominantly linked to the wb* region. These results indicated a cassette-like organization of the wb* region, with the conserved genes (gmhD and rjg) flanking the divergent, serogroup-specific wb* genes and IS1358. A similar organization of the wb* region in other serogroups raises the possibility of the emergence of new pathogens by homologous recombination via the junction genes.

The Vibrio cholerae genome contains two unique circular chromosomes.

Vibrio cholerae, the etiologic agent of the diarrheal disease cholera, is a Gram-negative bacterium that belongs to the gamma subdivision of the family Proteobacteriaceae. The physical map of the genome has been reported, and the genome has been described as a single 3.2-Mb chromosome [Majumder, R., et al. (1996) J. Bacteriol. 178, 1105-1112]. By using pulsed-field gel electrophoresis of genomic DNA immobilized in agarose plugs and digested with the restriction enzymes I-CeuI, SfiI, and NotI, we have also constructed the physical map of V. cholerae. Our analysis estimates the size of the genome at 4.0 Mb, 25% larger than the physical map reported by others. Our most notable finding is, however, that the V. cholerae chromosome appears to be not the single chromosome reported but two unique and separate circular megareplicons.