Polymorphisms rs763110 in FASL is linked to hepatitis C virus infection among high-risk populations.

BACKGROUND: The Fas cell surface death receptor (FAS) and Fas ligand (FASL) can participate in the apoptosis of immune cells and target cells infected with a virus through the FAS-FASL signalling pathway. The decoy receptor 3 (DCR3) can competitively inhibit the binding of FAS to FASL. Our aim is to investigate the effect of single nucleotide polymorphisms (SNPs) in FAS, FASL and DCR3 on hepatitis C virus (HCV) infection. METHODS: Four SNPs (rs763110 in FASL, rs1324551 and rs2234767 in FAS and rs2257440 in DCR3) were genotyped in 1495 controls free of HCV, 522 individuals with spontaneous HCV clearance and 732 patients with hepatitis C virus infection. The RegulomeDB database and RNAfold web servers were used to explore potential biological functions of SNPs. RESULTS: FASL rs763110 was associated with susceptibility to HCV infection, and not to CHC. The odds ratio (95% confidence interval) of HCV infection in high-risk populations carrying FASL rs763110-TT was 1.82 (1.36-2.51, P < 0.001) compared to that of CC genotypes and 1.93 (1.43-2.60, P < 0.001) higher than that of CC + CT genotypes. Based on computer simulation, FASL rs763110-T may affect the transcription of mRNA by affecting the binding of a transcription factor, leading to structural changes in mRNA. CONCLUSION: The genetic variant in FASL is linked with HCV infection, but not to spontaneous HCV clearance.

Fluoroscopy-guided gastric peroral endoscopic pyloromyotomy (G-POEM): a more reliable and efficient method for treatment of refractory gastroparesis.

INTRODUCTION: Prior studies show promising results of the gastric peroral endoscopic pyloromyotomy (G-POEM) procedure for treatment of refractory gastroparesis. One major technical challenge involved in this procedure is identifying the pyloric muscular ring (PMR). The aim of this study is to establish a reliable method for identification of the PMR during G-POEM. METHODS: Fluoroscopy-guided G-POEM was performed by placing an endoclip at the 9 to 11'o clock position at the pylorus for identification of PMR. Conventional G-POEM was performed by observation of blue colored mucosa at the pylorus area as an indirect marker for PMR. The degree of the PMR identification was graded into well identified, identified, and not identified based on the appearance of the PMR. Procedure times were accurately documented. Gastroparesis cardinal symptoms index and gastric emptying scintigraphy were evaluated before and after the procedure. RESULTS: Fourteen patients were studied, seven underwent fluoroscopy-guided G-POEM, and seven patients underwent conventional G-POEM. All procedures achieved technical success and no adverse events occurred. In the seven patients who underwent fluoroscopy-guided G-POEM, the PMR was well identified in four patients and identified in three patients. In the seven patients who underwent conventional G-POEM, the PMR was identified in four patients and not identified in three patients. The average time to complete the fluoroscopy-guided G-POEM was significantly shorter than that of the conventional G-POEM. CONCLUSIONS: Fluoroscopy-guided G-POEM by placement of an endoclip at the pylorus was a reliable and safe method to direct the orientation of the submucosal tunnel, to facilitate the location of the PMR, and to shorten the procedure time.

Passive transfer of lipopolysaccharide-derived myeloid-derived suppressor cells inhibits asthma-related airway inflammation.

OBJECTIVE: Myeloid-derived suppressor cells (MDSCs) have recently been implicated in the pathogenesis of asthma through inhibiting T cell response. However, the issue of whether Lipopolysaccharide (LPS)-derived MDSCs regulate the immune response in an asthma environment is currently unclear. We sought to characterize the pathogenic function of various subtypes of MDSCs in asthma mediated by ovalbumin in mice model, in order to show that LPS-induced MDSCs can shift the balance back to normal in a Th2-dominant asthmatic environment. MATERIALS AND METHODS: Subgroups of MDSCs with Ly6C+Ly6G+, Ly6C-Ly6G+, Ly6C+Ly6G- or Ly6C-Ly6G- expression were isolated by flow cytometry and were co-cultured with spleen lymphocytes. The proportion of Th1, Th2, or Treg cells in the treated spleen lymphocytes were analyzed by flow cytometry. In an ovalbumin (OVA)-induced mouse asthma model, mice were intravenously injected (tail vein) by MDSCs with specific marker, then the lung function and tissue pathology, IL-4 content in bronchoalveolar lavage fluid (BALF) and peripheral blood, and proportion of Th1, Th2, or Treg cells in peripheral blood were analyzed. RESULTS: Ly6C+Ly6G+ MDSCs transferred into asthmatic mice via intravenous injection suppressed the infiltration of inflammatory cells into the lung and Th2 cytokine in BALF and blood. We observed a significant increase of Treg cells in the spleen lymphocytes co-cultured with Ly6C+Ly6G+, Ly6C-Ly6G+, Ly6C+Ly6G-, Ly6C-Ly6G- or CD11b+ MDSCs. The adoptive transfer of Ly6C+Ly6G+, Ly6C-Ly6G+, CD11b+ MDSCs resulted in decrease of Penh, total cell number, eosinophil and neutrophil percentage in BALF, and concentration of IL-4 in BALF and serum, thus improving the inflammatory injury, histopathology and lung function in the mice with asthma. The up-regulation of the Th1/Th2 ratio and Treg frequency were observed after adoptive transfer of Ly6C+Ly6G+, Ly6C-Ly6G+, Ly6C+Ly6G-, Ly6C-Ly6G- and CD11b+ MDSCs. CONCLUSIONS: The LPS-derived MDSCs with specific markers were able to suppress natural inflammatory response and improve inflammatory injury through reversing Th1/Th2 ratio, increasing Treg proportion and decreasing IL-4 concentration. These findings imply that LPS-derived MDSCs inhibit Th2 cell-medicated response against allergen. We propose that asthma may be effectively targeted using a novel MDSC-based cell therapy approach.

Role of cysteine residues in human plasma phospholipid transfer protein.

Phospholipid transfer protein (PLTP) belongs to a family of human plasma lipid transfer proteins that bind to small amphophilic molecules. PLTP contains cysteines at residues 5, 129, 168, and 318. Bactericidal/permeability-increasing protein, which is a member of the same gene family, contains an essential disulfide bond between Cys135 and Cys175; these residues, which correspond to Cys129 and Cys168 in PLTP, are conserved among all known members of the gene family. To identify the importance of these and the remaining cysteine residues to PLTP secretion and activity, each was replaced by a glycine by site-directed mutagenesis. The mutant as well as wild-type PLTP cDNAs were cloned into the mammalian expression vector pSV.SPORT1, and the PLTP cDNAs were transfected to COS-6 cells for expression. PLTP Cys129 --> Gly and PLTP Cys168 --> Gly were secretion incompetent. Neither PLTP mass nor activity was detectable in cell lysates and culture medium. Relative to wild-type PLTP, PLTP Cys5 --> Gly and PLTP Cys318 --> Gly exhibited similar specific activities but partially impaired PLTP synthesis and secretion. Intracellular PLTP appeared as two bands of 75 and 51 kDa corresponding to reported molecular masses for the glycosylated and nonglycosylated forms. The specific activities of PLTP Cys5 --> Gly and PLTP Cys318 --> Gly were similar in the cell lysates and medium, suggesting that glycosylation does not affect transfer activity.

Roles of cysteines in human lecithin:cholesterol acyltransferase.

Human lecithin:cholesterol acyltransferase (LCAT, E.C.2.3.1.43) is a serine-type esterase that contains six cysteines, two of which, Cys31 and Cys184, are free. The remaining cysteines form disulfide links. One of these is between Cys50 and Cys74 and the other is between Cys313 and Cys356. The cDNA of LCAT and mutants in which one or two of the six cysteines were replaced by glycine was expressed in COS-6 cells. Polymerase chain reactions and Northern blot analysis indicated that LCAT mRNA was produced by all transfectants. Western blots of all transfected cells probed with a polyclonal antibody revealed intracellular LCAT. Substitution of glycine for either Cys50, Cys74, Cys313, or Cys356 was associated with a nearly total absence of activity in the medium. No protein was secreted when glycine replaced either of the amino acid residues that link Cys313 and Cys356. The small amounts of the Cys50-->Gly and Cys74-->Gly mutants found in the medium had specific activities that were much lower than that of the wild-type LCAT. All other transfectants secreted immunologically measurable amounts of active enzyme. Mutants in which one or both free cysteines, Cys31 and Cys184, were replaced with glycine were less active than the wild type and only partially inhibited by a sulfhydryl blocking reagent. The substrate specificities of the Cys31-->Gly and Cys184-->Gly mutants differed from that of the wild type.(ABSTRACT TRUNCATED AT 250 WORDS)