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Psoriasis genomics: analysis of proinflammatory (type 1) gene expression in large plaque (Western) and small plaque (Asian) psoriasis vulgaris.

BACKGROUND: Type 1 T cells are hypothesized to be central in the immunopathogenesis of psoriasis. Through elaboration of interferon (IFN)-gamma, type 1 T cells regulate the expression of many 'downstream' inflammatory genes, including an array of chemokines that regulate leucocyte trafficking and activation in skin lesions. Accordingly, disease progression and/or severity might be controlled by the degree to which differing cytokines and chemokines are overexpressed in focal skin regions. To examine this possibility, we studied two forms of chronic psoriasis vulgaris that differ significantly in overall severity and progression: small plaque (SP) psoriasis occurring in Korean patients, and large plaque (LP) psoriasis occurring in North American patients. OBJECTIVES: To characterize LP and SP psoriasis vulgaris with respect to expression of proinflammatory genes that define the type 1 T-cell axis in skin lesions [genes encoding interleukin (IL)-12, IFN-gamma, and IFN-gamma-regulated chemokines or inflammatory mediators]. METHODS: Total cellular RNA of skin samples from groups of patients with LP or SP psoriasis was analysed by quantitative reverse transcription-polymerase chain reaction (TaqMan analysis) to compare the differences in mRNA expression of genes related to the IFN-gamma pathway. RESULTS: The mRNA expression of keratin 16, CD25, IFN-gamma, IL-12 p40, signal transducer and activator of transcription-1, inducible nitric oxide synthase, IL-8, macrophage inflammatory protein-3alpha, monocyte chemoattractant protein-1, S100A12, IFN-gamma-inducible protein of 10 kDa, IFN-inducible T-cell alpha-chemoattractant and monokine induced by IFN-gamma was increased in the lesions of both LP psoriasis and SP psoriasis. However, IL-18 mRNA expression was significantly different in the lesions of LP psoriasis in comparison with those of SP psoriasis. CONCLUSIONS: The results indicate that proinflammatory type 1 genes regulated by IFN-gamma are similarly increased in both SP and LP psoriasis, but a potential difference in IL-18 exists between these disease forms. The consistent activation of this set of genes argues for a central role of IFN-gamma as a molecular regulator of inflammation in these distinct subtypes of psoriasis vulgaris. In contrast, disease extent/severity must be controlled by yet other factors.

Adult↗

Liposome-mediated transfer of vascular endothelial growth factor cDNA augments survival of random-pattern skin flaps in the rat.

Tissue engineering is an application for gene therapy that is in its infancy. We show that simple liposomal-mediated gene transfer could result in a potentially useful biological effect in the field of wound healing. cDNA encoding the 165 amino acid form of vascular endothelial growth factor complexed to commercially available liposomes was injected into rat skin 1 week before raising a random pattern 3 x 10 cm flap. The flap survival was enhanced by 14 percent, and was accomplished without accessing the arterial inflow of the territory. These results were statistically significant (p<0.002) and reproducible. No adverse effects were seen. Histological analysis of the angiogenesis localized much of the new vessel formation to the area around the hair follicles. Polymerase chain reaction amplification of extracted flap tissue confirmed the presence of the transgene.

Animals↗

Genomic analysis of Borrelia japonica sp. nov. isolated from Ixodes ovatus in Japan.

Genetic characteristics of 12 Borrelia isolates from the tick, Ixodes ovatus, I. persulcatus, and the rodent, Apodemus speciosus ainu, in Japan were compared to members of the three genospecies of Borrelia burgdorferi sensu lato; B. burgdorferi sensu stricto, B. garinii and group VS461. The methods used in this study were the quantitative microplate DNA hybridization assay and restriction fragment length polymorphism (RFLP) analyses of the flagellin structural genes and the 16S rRNA genes. The six isolates from I. persulcatus and A. speciosus ainu were identified as genospecies B. garinii using RFLP analysis of the flagellin and 16S rRNA genes. In contrast, RFLP analysis of the six isolates from I. ovatus indicated that they were different from the three reported genospecies. DNA homology studies confirmed the RFLP results. The six isolates from I. ovatus had DNA homologies ranging from 85 to 99%, whereas DNA relatedness of the I. ovatus isolate with strains belonging to the three genospecies was 50 to 64%. These results suggest that the strains isolated from I. ovatus in Japan differ from the three genospecies and should be classified as a new genospecies of B. burgdorferi sensu lato. We propose that strains isolated from I. ovatus should be classified as B. japonica sp. nov.

Animals↗

Construction, transfer and properties of a novel temperature-sensitive integrable plasmid for genomic analysis of Staphylococcus aureus.

As an alternative approach to genetic transfer and analysis, a novel integrable plasmid system was developed that should prove useful for mapping and cloning various genes in Staphylococcus aureus and other Gram-positive bacteria. The use of a restriction-deficient recipient strain and an improved protocol for protoplast plasmid transformation facilitated direct cloning of a recombinant plasmid (pPQ126) in S. aureus NCTC 8325-4. Plasmid pPQ126 (13.6 kb) is a novel, temperature-sensitive integrable plasmid containing genes encoding resistance to erythromycin and chloramphenicol (from plasmid pTV1ts), and resistance to gentamicin (from transposon Tn4001). When introduced into an appropriate recipient strain at the permissive temperature (30 degrees C), pPQ126 replicates autonomously. Integration of pPQ126 is directed into homologous chromosomal target sequences (chromosomal insertions of Tn551 or Tn4001) by growing a population of cells containing autonomous pPQ126 in the presence of gentamicin, erythromycin, and chloramphenicol at 39 degrees C (nonpermissive temperature). Elevated temperature both selects for and maintains pPQ126 as an integrated replicon. Integration of pPQ126 occurs at significantly reduced frequency in a recombination-deficient host, and does not occur in the absence of host chromosomal homology. Integrated pPQ126 excises from the chromosome under permissive conditions (30 degrees C), and excision results in derivatives of pPQ126 that harbour DNA of chromosomal origin.

Chromosomes↗

Genomic analysis of the F subtypes of human complement factor B.

Factor B of human complement is encoded within the Major Histocompatibility Complex (MHC) and is polymorphic, with up to 30 alleles defined by electrophoretic mobility. One of the most common alleles, BF*F, is subdivided into the FA and FB subtypes, which differ at the gene level by non-synonymous base substitutions in the seventh codon. We have found at this position a new restriction site polymorphism, as a Bsl I site absent from the FB allele. Using this restriction polymorphism, we have developed a method for BF F subtype determination, based on amplification by polymerase chain reaction of the 5' end of the BF gene, and digestion with Bsl I. This new method has been applied to a panel of 29 selected BF F individuals. A single strand DNA conformation analysis of the same region of the gene allowed us to confirm the above DNA-based BF F subtyping. During this study, two BF*F1 alleles showed discrepancies between protein and DNA typing, which were confirmed by our sequencing data. These were identical, in the 5' region, to BF*S and BF*FB genes, respectively. In a comparison with two protein subtyping methods, identical results were found for only one third of the selected samples. The conflicting results may arise, in part, from previously undescribed molecular heterogeneity within BF F subtypes, or from the presence of a null allele. Our new method allows BF*F subtyping to be used with confidence in the definition of disease-associated MHC haplotypes.

Alleles↗

Genome analysis.

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Algorithms↗

Molecular and genomic analysis of genes encoding surface-anchored proteins from Clostridium difficile.

The gene slpA, encoding the S-layer precursor protein in the virulent Clostridium difficile strains C253 and 79--685, was identified. The precursor protein carries a C-terminal highly conserved anchoring domain, similar to the one found in the Cwp66 adhesin (previously characterized in strain 79--685), an SLH domain, and a variable N-terminal domain mediating cell adherence. The genes encoding the S-layer precursor proteins and the Cwp66 adhesin are present in a genetic locus carrying 17 open reading frames, 11 of which encode a similar two-domain architecture, likely to include surface-anchored proteins.

Amino Acid Sequence↗

Functional genomic analysis of three nitrogenase isozymes in the photosynthetic bacterium Rhodopseudomonas palustris.

The photosynthetic bacterium Rhodopseudomonas palustris is one of just a few prokaryotes described so far that has vnf and anf genes for alternative vanadium cofactor (V) and iron cofactor (Fe) nitrogenases in addition to nif genes for a molybdenum cofactor (Mo) nitrogenase. Transcriptome data indicated that the 32 genes in the nif gene cluster, but not the anf or vnf genes, were induced in wild-type and Mo nitrogenase-expressing strains grown under nitrogen-fixing conditions in Mo-containing medium. Strains that were unable to express a functional Mo nitrogenase due to mutations in Mo nitrogenase structural genes synthesized functional V and Fe nitrogenases and expressed vnf and anf genes in nitrogen-fixing growth media that contained Mo and V at concentrations far in excess of those that repress alternative nitrogenase gene expression in other bacteria. Thus, not only does R. palustris have multiple enzymatic options for nitrogen fixation, but in contrast to reports on other nitrogen-fixing bacteria, the expression of its alternative nitrogenases is not repressed by transition metals. Between 95 and 295 genes that are not directly associated with nitrogenase synthesis and assembly were induced under nitrogen-fixing conditions, depending on which nitrogenase was being used by R. palustris. Genes for nitrogen acquisition were expressed at particularly high levels during alternative nitrogenase-dependent growth. This suggests that alternative nitrogenase-expressing cells are relatively starved for nitrogen and raises the possibility that fixed nitrogen availability may be the primary signal that controls the synthesis of the V and Fe nitrogenases.

Adaptation, Physiological↗

Progression or resolution of coxsackievirus B4-induced pancreatitis: a genomic analysis.

Group B coxsackieviruses are associated with chronic inflammatory diseases of the pancreas, heart, and central nervous system. Chronic pancreatitis, which can develop from acute pancreatitis, is considered a premalignant disorder because it is a major risk factor for pancreatic cancer. To explore the genetic events underlying the progression of acute to chronic disease, a comparative analysis of global gene expression during coxsackievirus B4-induced acute and chronic pancreatitis was undertaken. A key feature of acute pancreatitis that resolved was tissue regeneration, which was accompanied by increased expression of genes involved in cell growth, inhibition of apoptosis, and embryogenesis and by increased division of acinar cells. Acute pancreatitis that progressed to chronic pancreatitis was characterized by lack of tissue repair, and the expression map highlighted genes involved in apoptosis, acinoductular metaplasia, remodeling of the extracellular matrix, and fibrosis. Furthermore, immune responses appeared skewed toward development of alternatively activated (M2) macrophages and T helper 2 (Th2) cells during disease that resolved and toward classically activated (M1) macrophages and Th1 cells during disease that progressed. Our hypothesis is that growth and differentiation signals coupled with the M2/Th2 milieu favor acinar cell proliferation, while diminished growth signals and the M1/Th1 milieu favor apoptosis of acinar cells and remodeling/proliferation of the extracellular matrix, resulting in fibrosis.

Animals↗

Random amplified polymorphic DNA analysis, genome size, and genomic in situ hybridization of triploid viviparous onions

Triploid viviparous onions (Allium cepa L. var. viviparum Metzg. (ALEF.), auct.), (2n = 3x = 24), are known in some countries only as a rare relic crop, while in other parts of the world they are still traditionally or even commercially cultivated. Results indicating an identical random amplified polymorphic DNA (RAPD) banding pattern and the same DNA content (2C = 43.4 pg) establish the high genetic similarity and the unique origin of the Croatian clone Ljutika and the Indian clone Pran. In order to determine the parental Allium species of these natural triploid hybrids, genomic fluorescent in situ hybridization (GISH) was applied. Biotinylated genomic DNAs from six diploid Allium species (A. cepa L., A. fistulosum L., A. roylei Stearn, A. vavilovii M. Pop. et Vved., A. galanthum Kar. et Kir., A. oschaninii O. Fedtsch.) were used as probes in this study. While probes obtained from genomic DNA of A. cepa, A. vavilovii, and A. roylei hybridized to somatic chromosomes of Ljutika probes from A. fistulosum, A. galanthum, and A. oschaninii did not. The DNA probes of A. cepa and A. roylei each completely or predominantly labelled one genome (eight chromosomes). A few chromosomes, the markers of the triploid karyotype, were not completely labelled by any probe applied. Our GISH results indicate that triploid viviparous onions might possess a complex triparental genome organization.

Journal Article↗

Efficacy and Genomic Analysis of HER2-Mutant Metastatic Triple-Negative Breast Cancer Treated with Neratinib Alone or with Trastuzumab in the SUMMIT Basket Trial.

PURPOSE: Human epidermal growth factor receptor 2 (HER2) mutations occur in 1% to 3% of triple-negative breast cancers (TNBC), representing a novel target for biomarker-directed treatment. In the SUMMIT basket trial (NCT01953926), patients with HER2-mutant, metastatic TNBC received neratinib (240 mg/day) or neratinib + trastuzumab (N + T; neratinib 240 mg/day, intravenous trastuzumab 8 mg/kg initially and then 6 mg/kg every 3 weeks). We report final results from the neratinib and N + T TNBC cohorts. PATIENTS AND METHODS: Primary endpoint: investigator-assessed objective response rate at first postbaseline tumor assessment (ORRfirst); secondary endpoints included confirmed ORR by investigator, clinical benefit rate (CBR), and progression-free survival (PFS); exploratory endpoint included circulating tumor DNA (ctDNA) collected at baseline, during treatment, and at the end of treatment. RESULTS: Twenty-seven patients were enrolled between July 2014 and September 2021. Confirmed ORRs were 40% [95% confidence interval (CI), 12.2-73.8] for neratinib (n = 10) and 35.3% (95% CI, 14.2-61.7) for N + T (n = 17). CBRs were 40% (95% CI, 12.2-73.8) and 47.1% (95% CI, 23-72.2), respectively; median PFS times were 2.89 (95% CI, 0.95-5.52) and 6.24 months (95% CI, 2.10-8.18), respectively. HER2 mutation variant allele frequencies in ctDNA from patients with response or stable disease decreased upon treatment and increased upon progression. Serial ctDNA sequencing revealed emergence or increase in on-pathway (ERBB3) and off-pathway (KRAS and TP53) mutations. The most common treatment-emergent adverse events were diarrhea, nausea, and constipation. CONCLUSIONS: N + T in patients with HER2-mutant metastatic TNBC seemed to prolong responses versus neratinib alone, representing a novel approach for patients with biomarker-defined metastatic TNBC. Based on these and previously published data, neratinib-based combinations are endorsed by the National Comprehensive Cancer Network guidelines for patients with hormone receptor-positive or -negative metastatic breast cancer with activating HER2 mutations. See related commentary by Lloyd et al., p. 3715.

Adult↗

Genome analysis of BK (WW) viral DNA cloned directly from human urine.

DNA from a third isolate of the WW strain of BK virus was prepared from human urine and was cloned into the BamHI site of pBR322. Restriction mapping showed a number of changes relative to the prototype BK viral DNA, including the presence of a new PstI, an SstI, and an AvaII site and the loss of a HindIII, an SstI, and an NcoI site. There is evidence for more extensive changes in the vicinity of the origin of replication.

BK Virus↗