Polymorphisms in RYBP and AOAH Genes Are Associated with Chronic Rhinosinusitis in a Chinese Population: A Replication Study

BACKGROUND: The development of CRS is believed to be the result of combined interactions between the genetic background of the affected subject and environmental factors. OBJECTIVES: To replicate and extend our recent findings from genetic association studies in chronic rhinosinusitis (CRS) performed in a Canadian Caucasian population in a Chinese population. METHODS: In a case-control replication study, DNA samples were obtained from CRS with (n  = 306; CRSwNP) and without (n = 332; CRSsNP) nasal polyps, and controls (n = 315) in a Chinese population. A total of forty-nine single nucleotide polymorphisms (SNPs) selected from previous identified SNPs associated with CRS in Canadian population, and SNPs from the CHB HapMap dataset were individually genotyped. RESULTS: We identified two SNPs respectively in RYBP (rs4532099, p = 2.15E-06, OR = 2.59) and AOAH (rs4504543, p = 0.0001152, OR = 0.58) significantly associated with whole CRS cohort. Subgroup analysis for the presence of nasal polyps (CRSwNP and CRSsNP) displayed significant association in CRSwNP cohorts regarding to one SNP in RYBP (P = 3.24(E)-006, OR = 2.76). Evidence of association in the CRSsNP groups in terms of 2 SNPs (AOAH_rs4504543 and RYBP_rs4532099) was detected as well. Stratifying analysis by gender demonstrated that none of the selected SNPs were associated with CRSwNP as well as CRSsNP. Meanwhile 3 SNPs (IL1A_rs17561, P = 0.005778; IL1A_rs1800587, P = 0.009561; IRAK4_rs4251513, P = 0.03837) were associated with serum total IgE level. CONCLUSIONS: These genes are biologically plausible, with roles in regulation of transcription (RYBP) and inflammatory response (AOAH). The present data suggests the potential common genetic basis in the development of CRS in Chinese and Caucasian population

Essential Domains of Anaplasma phagocytophilum Invasins Utilized to Infect Mammalian Host Cells

Anaplasma phagocytophilum causes granulocytic anaplasmosis, an emerging disease of humans and domestic animals. The obligate intracellular bacterium uses its invasins OmpA, Asp14, and AipA to infect myeloid and non-phagocytic cells. Identifying the domains of these proteins that mediate binding and entry, and determining the molecular basis of their interactions with host cell receptors would significantly advance understanding of A. phagocytophilum infection. Here, we identified the OmpA binding domain as residues 59 to 74. Polyclonal antibody generated against a peptide spanning OmpA residues 59 to 74 inhibited A. phagocytophilum infection of host cells and binding to its receptor, sialyl Lewis x (sLex-capped P-selectin glycoprotein ligand 1. Molecular docking analyses predicted that OmpA residues G61 and K64 interact with the two sLex sugars that are important for infection, α2,3-sialic acid and α1,3-fucose. Amino acid substitution analyses demonstrated that K64 was necessary, and G61 was contributory, for recombinant OmpA to bind to host cells and competitively inhibit A. phagocytophilum infection. Adherence of OmpA to RF/6A endothelial cells, which express little to no sLex but express the structurally similar glycan, 6-sulfo-sLex, required α2,3-sialic acid and α1,3-fucose and was antagonized by 6-sulfo-sLex antibody. Binding and uptake of OmpA-coated latex beads by myeloid cells was sensitive to sialidase, fucosidase, and sLex antibody. The Asp14 binding domain was also defined, as antibody specific for residues 113 to 124 inhibited infection. Because OmpA, Asp14, and AipA each contribute to the infection process, it was rationalized that the most effective blocking approach would target all three. An antibody cocktail targeting the OmpA, Asp14, and AipA binding domains neutralized A. phagocytophilumbinding and infection of host cells. This study dissects OmpA-receptor interactions and demonstrates the effectiveness of binding domain-specific antibodies for blocking A. phagocytophilum infection

Lysine-based surfactants in nanovesicle formulations: the role of cationic charge position and hydrophobicity in in vitro cytotoxicity and intracellular delivery

Understanding nanomaterial interactions within cells is of increasing importance for assessing their toxicity and cellular transport. Here, we developed nanovesicles containing bioactive cationic lysine-based amphiphiles, and assessed whether these cationic compounds increase the likelihood of intracellular delivery and modulate toxicity. We found different cytotoxic responses among the formulations, depending on surfactant, cell line and endpoint assayed. The induction of mitochondrial dysfunction, oxidative stress and apoptosis were the general mechanisms underlying cytotoxicity. Fluorescence microscopy analysis demonstrated that nanovesicles were internalized by HeLa cells, and evidenced that their ability to release endocytosed materials into cell cytoplasm depends on the structural parameters of amphiphiles. The cationic charge position and hydrophobicity of surfactants determine the nanovesicle interactions within the cell and, thus, the resulting toxicity and intracellular behavior after cell uptake of the nanomaterial. The insights into some toxicity mechanisms of these new nanomaterials contribute to reducing the uncertainty surrounding their potential health hazards

Overproduction of acyloxyacyl hydrolase by macrophages and dendritic cells prevents prolonged reactions to bacterial lipopolysaccharide in vivo.

Although recognition of lipopolysaccharide (LPS) by the myeloid differentiation factor 2-Toll-like receptor 4 complex is important for triggering protective inflammatory responses in animals, terminating many of these responses requires LPS inactivation by a host lipase, acyloxyacyl hydrolase (AOAH). To test whether endogenously produced recombinant AOAH can modulate responses to LPS and gram-negative bacteria, we engineered transgenic mice that overexpress AOAH in dendritic cells and macrophages, cell types that normally produce it. Transgenic mice deacylated LPS more rapidly than did wild-type controls. They also were protected from LPS-induced hepatosplenomegaly, recovered more quickly from LPS-induced weight loss, and were more likely to survive when challenged with live Escherichia coli. Constitutive overexpression of AOAH in vivo hastened recovery from LPS exposure without interfering with the normal acute inflammatory response to this important microbial signal molecule. Our results suggest that the extent to which macrophages and dendritic cells produce AOAH may influence the outcome of many gram-negative bacterial diseases

Ehrlichia chaffeensis Uses Its Surface Protein EtpE to Bind GPI-Anchored Protein DNase X and Trigger Entry into Mammalian Cells

Ehrlichia chaffeensis, an obligatory intracellular rickettsial pathogen, enters and replicates in monocytes/macrophages and several non-phagocytic cells. E. chaffeensis entry into mammalian cells is essential not only for causing the emerging zoonosis, human monocytic ehrlichiosis, but also for its survival. It remains unclear if E. chaffeensis has evolved a specific surface protein that functions as an ‘invasin ’ to mediate its entry. We report a novel entry triggering protein of Ehrlichia, EtpE that functions as an invasin. EtpE is an outer membrane protein and an antibody against EtpE (the C-terminal fragment, EtpE-C) greatly inhibited E. chaffeensis binding, entry and infection of both phagocytes and non-phagocytes. EtpE-Cimmunization of mice significantly inhibited E. chaffeensis infection. EtpE-C-coated latex beads, used to investigate whether EtpE-C can mediate cell invasion, entered both phagocytes and non-phagocytes and the entry was blocked by compounds that block E. chaffeensis entry. None of these compounds blocked uptake of non-coated beads by phagocytes. Yeast twohybrid screening revealed that DNase X, a glycosylphosphatidyl inositol-anchored mammalian cell-surface protein binds EtpE-C. This was confirmed by far-Western blotting, affinity pull-down, co-immunoprecipitation, immunofluorescence labeling, and live-cell image analysis. EtpE-C-coated beads entered bone marrow-derived macrophages (BMDMs) from wildtype mice, whereas they neither bound nor entered BMDMs from DNase X-/- mice. Antibody against DNase X or DNase X knock-down by small interfering RNA impaired E. chaffeensis binding, entry, and infection. E. chaffeensis entry and infectio