Chemical xenobiotics and mitochondrial autoantigens in primary biliary cirrhosis: identification of antibodies against a common environmental, cosmetic, and food additive, 2-octynoic acid

Emerging evidence has suggested environmental factors as causative agents in the pathogenesis of primary biliary cirrhosis (PBC). We have hypothesized that in PBC the lipoyl domain of the immunodominant E2 component of pyruvate dehydrogenase (PDC-E2) is replaced by a chemical xenobiotic mimic, which is sufficient to break self-tolerance. To address this hypothesis, based upon our quantitative structure-activity relationship data, a total of 107 potential xenobiotic mimics were coupled to the lysine residue of the immunodominant 15 amino acid peptide of the PDC-E2 inner lipoyl domain and spotted on microarray slides. Sera from patients with PBC (n = 47), primary sclerosing cholangitis (n = 15), and healthy volunteers (n = 20) were assayed for Ig reactivity. PBC sera were subsequently absorbed with native lipoylated PDC-E2 peptide or a xenobiotically modified PDC-E2 peptide, and the remaining reactivity analyzed. Of the 107 xenobiotics, 33 had a significantly higher IgG reactivity against PBC sera compared with control sera. In addition, 9 of those 33 compounds were more reactive than the native lipoylated peptide. Following absorption, 8 of the 9 compounds demonstrated cross-reactivity with lipoic acid. One compound, 2-octynoic acid, was unique in both its quantitative structure-activity relationship analysis and reactivity. PBC patient sera demonstrated high Ig reactivity against 2-octynoic acid-PDC-E2 peptide. Not only does 2-octynoic acid have the potential to modify PDC-E2 in vivo but importantly it was/is widely used in the environment including perfumes, lipstick, and many common food flavorings.     

Cigarette smoke extract increases S-adenosylmethionine and cystathionine in human lung epithelial-like (A549) cells

The effect of cigarette smoke extract (CSE) on S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and sulfur amino acid metabolism was examined in human lung epithelial-like (A549) cells exposed to various CSE concentrations (2.5-100%) for 24 or 48 h. Intracellular SAM and SAM/SAH ratio were elevated after exposure to CSE for 48 h. Cell SAH content decreased, but the effect was not consistent. Cellular cystathionine, cysteine, and methionine levels were increased after CSE exposure for 48h. Sub-acute exposure to CSE induced increases in cellular SAM and SAM/SAH ratio. The transsulfuration pathway was likely activated by CSE since cystathionine increased, potentially contributing to the increased total intracellular GSH content.     

Expansion of bone marrow IFN-alpha-producing dendritic cells in New Zealand Black (NZB) mice: high level expression of TLR9 and secretion of IFN-alpha in NZB bone marrow

Patients with systemic lupus erythematosus have elevated IFN-alpha production. Furthermore, sera IFN-alpha levels correlate with disease activity. We have focused our attention on whether this phenotype is also seen in the New Zealand Black (NZB) mice and simultaneously addressed the underlying mechanisms. Specifically, we analyzed: 1) levels of sera IFN-alpha after type A CpG ODN 2216 injection in autoimmunity-prone NZB and control mice, and 2) levels of IFN-alpha synthesized by IFN-alpha-producing dendritic cells (IPDCs) using highly enriched populations of CD11c+B220+ IPDCs derived from NZB and control mice; IPDCs are divided into two subpopulations (CD4+CD11c+B220+ and CD4-CD11c+B220+). Our data demonstrate that NZB mice produced higher levels of sera IFN-alpha after type A CpG ODN 2216 injection when compared with control mice (p < 0.01). In addition, the cell numbers, frequency, and TLR9 mRNA levels of CD4+ and CD4- IPDC were markedly increased in the bone marrow (BM) of NZB mice. Upon in vitro stimulation with TLR9 ligand-CpG ODN 2216, higher levels of IFN-alpha were synthesized by IPDCs from the BM of NZB. The major contributor of IFN-alpha was the CD4-CD11c+B220+ IPDC subpopulation. Furthermore, NZB BM IPDCs manifest impaired expression of homing chemokine CCR7 and CD62L, and IL-12 production. These data on the functional characteristics of the IPDC lineages explain in part the mechanism of hyper-IFN-alpha production and help clarify the mechanism for the expansion of NZB BM IPDCs.     

Mutations in TRIOBP, which encodes a putative cytoskeletal-organizing protein, are associated with nonsyndromic recessive deafness

In seven families, six different mutant alleles of TRIOBP on chromosome 22q13 cosegregate with autosomal recessive nonsyndromic deafness. These alleles include four nonsense (Q297X, R788X, R1068X, and R1117X) and two frameshift (D1069fsX1082 and R1078fsX1083) mutations, all located in exon 6 of TRIOBP. There are several alternative splice isoforms of this gene, the longest of which, TRIOBP-6, comprises 23 exons. The linkage interval for the deafness segregating in these families includes DFNB28. Genetic heterogeneity at this locus is suggested by three additional families that show significant evidence of linkage of deafness to markers on chromosome 22q13 but that apparently have no mutations in the TRIOBP gene.     

Tricellulin is a tight-junction protein necessary for hearing

The inner ear has fluid-filled compartments of different ionic compositions, including the endolymphatic and perilymphatic spaces of the organ of Corti; the separation from one another by epithelial barriers is required for normal hearing. TRIC encodes tricellulin, a recently discovered tight-junction (TJ) protein that contributes to the structure and function of tricellular contacts of neighboring cells in many epithelial tissues. We show that, in humans, four different recessive mutations of TRIC cause nonsyndromic deafness (DFNB49), a surprisingly limited phenotype, given the widespread tissue distribution of tricellulin in epithelial cells. In the inner ear, tricellulin is concentrated at the tricellular TJs in cochlear and vestibular epithelia, including the structurally complex and extensive junctions between supporting and hair cells. We also demonstrate that there are multiple alternatively spliced isoforms of TRIC in various tissues and that mutations of TRIC associated with hearing loss remove all or most of a conserved region in the cytosolic domain that binds to the cytosolic scaffolding protein ZO-1. A wild-type isoform of tricellulin, which lacks this conserved region, is unaffected by the mutant alleles and is hypothesized to be sufficient for structural and functional integrity of epithelial barriers outside the inner ear.     

Enhancement of dissolution profile by solid dispersion (kneading) technique

This article investigates enhancement of the dissolution profile of valdecoxib using solid dispersion with PVP. The article also describes the preparation of fast-dissolving tablets of valdecoxib by using a high amount of superdisintegrants. A phase solubility method was used to evaluate the effect of various water-soluble polymers on aqueous solubility of valdecoxib. Polyvinyl pyrrolidone (PVP K-30) was selected and solid dispersions were prepared by the method of kneading. Dissolution studies, using the USP paddle method were performed for solid dispersions of valdecoxib. Infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and x-ray diffractometry (XRD) were performed to identify the physicochemical interaction between drug and carrier, hence its effect on dissolution. Tablets were formulated containing solid dispersion products and compared with commercial products. IR spectroscopy, XRD, and DSC showed no change in the crystal structure of valdecoxib. Dissolution of valdecoxib improved significantly in solid dispersion products (<85% in 5 minutes). Tablets containing solid dispersion exhibited better dissolution profile than commercial tablets. Thus, the solid dispersion technique can be successfully used for improvement of dissolution of valdecoxib. Published: August 18, 2006     

Multiple KIR gene polymorphisms are associated with plasma viral loads in SIV-infected rhesus macaques

Innate immune mechanisms play a deterministic role in the rate of disease progression during acute infection in HIV infected humans and SIV infection of non-human primates. The role NK cells play in mediating such an effect has thus gained importance. One of the major sets of molecules that regulate NK cell function are the killer cell immunoglobulin-like molecules (KIR’s). Our laboratory has previously shown an association of KIR3DL alleles 13 and 14 with high plasma viral loads in a cohort of SIV-infected rhesus macaques. To gain a more detailed understanding of the role of KIR polymorphisms, our laboratory herein conducted studies of three additional KIR loci and show that select KIR3DH alleles appear to be more strongly associated with high plasma viral loads than KIR3DL alleles 13 and 14. In addition, we herein document the existence of additional new alleles for the KIR1D, KIR2DL4, and the KIR3DH loci.     

Aryl hydrocarbon receptor agonists directly activate estrogen receptor alpha in MCF-7 breast cancer cells

The aryl hydrocarbon receptor (AhR) binds with high affinity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related halogenated aromatics, but also binds with lower affinity to structurally diverse exogenous and endogenous chemicals. One study reported that 3-methylcholanthrene (3MC) activated the estrogen receptor (ER) through the AhR, which acts as co-regulatory protein, whereas a recent report showed that 3MC directly bound and activated ERalpha. This study also shows that the AhR agonists benzo[a]pyrene, 3,3',4,4'-tetrachlorobiphenyl, chrysin, 6-methyl-1,3,8-trichlorodibenzofuran, and 3,3'-diindolylmethane also induce ERalpha-dependent transactivation. Moreover, in chromatin immunoprecipitation assays, these compounds induce binding of AhR and ERalpha to the CYP1A1 and pS2 gene promoters, which is consistent with their activities as both selective AhR modulators (SAhRMs) and selective ER modulators (SERMs).     

Modulation of human cortical swallowing motor pathways after pleasant and aversive taste stimuli

Human swallowing involves the integration of sensorimotor information with complexities such as taste; however, the interaction between the taste of food and its effects on swallowing control remains unknown. We assessed the effects of pleasant (sweet) and aversive (bitter) tastes on human cortical swallowing motor pathway excitability. Healthy adult male volunteers underwent a transcranial magnetic stimulation (TMS) mapping study (n = 9, mean age: 34 yr) to assess corticobulbar excitability before and up to 60 min after 10-min liquid infusions either 1) as swallowing tasks or 2) delivered directly into the stomach. Infusions were composed of sterile water (neutral), 10% glucose (sweet), and 0.5 mM quinine hydrochloride (bitter). The order of delivery was randomized, and each infusion was given on separate days. Pharyngeal motor-evoked potentials (PMEPs) were recorded from an intraluminal catheter as a measure of corticobulbar excitability and compared using repeated-measures and one-way ANOVA. After the swallowing task (water, glucose, or quinine), repeated-measures ANOVA revealed a significant time interaction across tastants (P 相似文献   

DFNB68, a novel autosomal recessive non-syndromic hearing impairment locus at chromosomal region 19p13.2

From a large collection of families with autosomal recessive non-syndromic hearing impairment (NSHI) from Pakistan, linkage has been established for two unrelated consanguineous families to 19p13.2. This new locus was assigned the name DFNB68. A 10 cM genome scan and additional fine mapping were carried out using microsatellite marker loci. Linkage was established for both families to DFNB68 with maximum multipoint LOD scores of 4.8 and 4.6. The overlap of the homozygous regions between the two families was bounded by D19S586 and D19S584, which limits the locus interval to 1.9 cM and contains 1.4 Mb. The genes CTL2, KEAP1 and CDKN2D were screened but were negative for functional sequence variants.Regie Lyn P. Santos and Muhammad Jawad Hassan contributed equally to this work.