Alpha-defensin DEFA1A3 gene copy number variation in Asians and its genetic association study in Chinese systemic lupus erythematosus patients

Neutrophil extracellular traps (NETs) were closely associated with activation of type I interferon (IFN) pathway in systemic lupus erythematosus (SLE). We aimed to study the genetic basis of NETs-DEFA1A3 copy number variations (CNV) in SLE and HapMap CHB + JPT populations by quantitative real-time PCR and whole genome sequences data. DEFA1A3 CNs did not differ significantly between SLE patients and controls. DEFA1A3 CNs ranged from 3 to 11 in CHB and 4 to 16 in JPT. The median of DEFA1A3 CNV of CHB (6 copies) was significantly lower than that of JPT (9 copies). Associations of genotype of tag SNP rs2738113 with DEFA1A3 CNs and mRNA expression of IFNα were observed in CHB and JPT populations. Our data provided a genetic reference of DEFA1A3 CNV for further studies and suggested that the genetic pathogenesis of NETs, as well as DEFA1A3 in SLE should be further evaluated, specially in different populations.     

In vitro immunization of Epstein–Barr virus-immortalized B cells augments antigen-specific antibody production

The current method for in vitro immunization (IVI) uses several antigens including toxins, food allergens, pathogenic bacteria, and self-antigen-derived peptides that induce an antigen-specific immune response in peripheral blood mononuclear cells (PBMCs). This protocol, however, requires donor blood collection and preparation of PBMCs before every IVI. In the present study, we aimed to design a more efficient system utilizing B cells immortalized with Epstein–Barr virus (EBV-B) as host cells for IVI to make antigen-specific antibodies. Results showed that previously antigen-sensitized, EBV-B cells exposed to the antigen along with IL-6, CpG oligonucleotides, and CD40 ligand signal produced antigen-specific antibodies. These results provide evidence for a novel and easy method to expand memory-type B cells and produce antigen-specific antibodies.     

Cytotoxic and Apoptosis‐Inducing Activities,and Anti‐Tumor‐Promoting Effects of Cyanogenated and Oxygenated Triterpenes

Two of each semisynthetic lanostane‐ and cycloartane‐type triterpenes with a cyano‐enone functionality, i.e., 13 and 18 , and 23 and 28 , respectively, sixteen of their synthetic intermediates, 9 – 12, 14 – 17, 19 – 22 , and 24 – 27 , along with seven semisynthetic oxygenated triterpene acetates, 29 – 35 , and eight natural hydroxy triterpenes, 1 – 8 , were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK‐BR‐3) cancer cell lines. One natural triterpene, 8 , and ten semisynthetic triterpenes, 9, 13, 15, 18, 23, 25, 28, 29, 32 , and 33 , exhibited potent cytotoxicities against one or more cell lines with IC₅₀ values in the range of 1.4–9.9 μM . Two lanostane‐type triterpenes with a cyano‐enone functionality, 3‐oxolanosta‐1,8,24‐triene‐2‐carbonitrile ( 13 ) and 3‐oxolanosta‐1,8‐diene‐2‐carbonitrile ( 18 ), induced apoptosis in HL60 cells, as observed by membrane phospholipid exposure in flow cytometry. Western blot analysis showed that 13 and 18 significantly reduced procaspases‐3, ‐8, and ‐9, and increased cleaved caspases‐3, ‐8, and ‐9. These findings indicated that compounds 13 and 18 induced apoptosis in HL60 cells via both the mitochondrial and the death receptor‐mediated pathways. In addition, upon evaluation of the inhibitory effects on Epstein? Barr virus early antigen (EBV‐EA) activation induced with 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in Raji cells, seven natural triterpenes, 1 – 6 and 8 , and ten semisynthetic triterpenes, 9, 10, 14, 15, 19, 20, 24, 25, 29 , and 30 , exhibited inhibitory effects which were higher than that of β‐carotene, a vitamin A precursor studied widely in cancer‐chemoprevention animal models.     

Mitotic stability of small supernumerary marker chromosomes depends on their shape and telomeres — A long term in vitro study

Mosaicism is present in more than 50% of the cases with small supernumerary marker chromosomes (sSMCs) and karyotype 47,XX,+mar/46,XX or 47,XY,+mar/46,XY. Recently we provided first evidence that the mitotic stability of sSMC is dependent on their structure, i.e. their shape. Thus, here we performed a long term in vitro study on 12 selected cell lines from the Else Kröner–Fresenius-sSMC-cellbank (http://ssmc-tl.com/ekf-cellbank.html) to test mitotic sSMC stability systematically. The obtained results showed that inverted duplicated shaped and also the so-called complex sSMCs (group 1) are by far more stable, than centric-minute- or ring-shaped sSMCs (groups 2). Generally speaking, the percentage of cells with group-1-sSMCs remained stable over 90 days of cell culture, while that of group-2-sSMCs in parts dramatically decreased. In one group-2-cell line the sSMC was even lost completely after 30 days of in vitro culture, in others the sSMC was depleted in up to 40% of the cells. Still the highest rate of sSMC loss was recorded during EBV-transformation. Overall, the major difference between groups 1 and 2 was the number of telomeres per sSMC. In group 1 the sSMCs had “original” telomeres at both of their ends; in group 2 the sSMCs had either no, possibly secondary acquired and/or only one original telomere. This absence of protective telomeric sequences in group 2 seems to make sSMC more susceptible for loss during cell division. Still, also a growth advantage of cells without sSMC cannot be neglected entirely.     

Hyper-IgD and periodic fever syndrome: a new MVK mutation (p.R277G) associated with a severe phenotype

Hyperimmunoglobulinemia D and periodic fever syndrome (HIDS; MIM# 260920) is a rare recessively-inherited autoinflammatory condition caused by mutations in the MVK gene, which encodes for mevalonate kinase, an essential enzyme in the isoprenoid pathway. HIDS is clinically characterized by recurrent episodes of fever and inflammation. Here we report on the case of a 2 year-old Portuguese boy with recurrent episodes of fever, malaise, massive cervical lymphadenopathy and hepatosplenomegaly since the age of 12 months. Rash, arthralgia, abdominal pain and diarrhea were also seen occasionally. During attacks a vigorous acute-phase response was detected, including elevated erythrocyte sedimentation rate, C-reactive protein, serum amyloid A and leukocytosis. Clinical and laboratory improvement was seen between attacks. Despite normal serum IgD level, HIDS was clinically suspected. Mutational MVK analysis revealed the homozygous genotype with the novel p.Arg277Gly (p.R277G) mutation, while the healthy non-consanguineous parents were heterozygous. Short nonsteroidal anti-inflammatory drugs and corticosteroid courses were given during attacks with poor benefits, whereas anakinra showed positive responses only at high doses. The p.R277G mutation here described is a novel missense MVK mutation, and it has been detected in this case with a severe HIDS phenotype. Further studies are needed to evaluate a co-relation genotype, enzyme activity and phenotype, and to define the best therapeutic strategies.     

Evaluation of novel derivatisation reagents for the analysis of oxysterols

Oxysterols are oxidised forms of cholesterol that are intermediates in the synthesis of bile acids and steroid hormones. They are also ligands to nuclear and G protein-coupled receptors. Analysis of oxysterols in biological systems is challenging due to their low abundance coupled with their lack of a strong chromophore and poor ionisation characteristics in mass spectrometry (MS). We have previously used enzyme-assisted derivatisation for sterol analysis (EADSA) to identify and quantitate oxysterols in biological samples. This technique relies on tagging sterols with the Girard P reagent to introduce a charged quaternary ammonium group. Here, we have compared several modified Girard-like reagents and show that the permanent charge is vital for efficient MSⁿ fragmentation. However, we find that the reagent can be extended to include sites for potential stable isotope labels without a loss of performance.     

Origin and Evolution of Viral Interleukin-10 and Other DNA Virus Genes with Vertebrate Homologues

Phylogenies of gene families including members in both vertebrates and DNA viruses of the poxvirus and/or herpesvirus families showed that the viral genes originated at widely different times over the history of life. Certain of these viral genes (for example, the genes encoding the large and small subunits of ribonucleoside–diphosphate reductase) originated before animals diverged from fungi, while others originated much more recently. The most striking examples of recent origin involved viral genes encoding the cytokine interleukin-10 (IL-10), which originated independently in viruses at least three times since the divergence of the orders of eutherian mammals, presumably by viral capture of host genes. In certain domains, viral IL-10 genes showed significantly higher rates of nonsynonymous substitution than their nearest mammalian homologues. Though the mutation rate in these viral genes is up to 20 times that of the corresponding mammalian genes, a high mutation rate alone did not account for these differences because they were not seen in all domains. Rather, in certain domains it appears that functional constraints present in the case of mammalian IL-10 are relaxed in the case of the viral homologues. Furthermore, a nonrandom pattern of change with respect to amino acid residue charge in the N-terminal portion of the mature protein has occurred repeatedly in independently derived viral IL-10 genes, strongly suggesting that positive selection has led to divergence of this functionally important domain in viral IL-10. Received: 11 January 2001 / Accepted: 23 May 2001