A comprehensive, tri-national, cross-sectional analysis of characteristics and impact of pruritus in psoriasis.

BACKGROUND: Pruritus is prevalent in psoriasis but still many features of pruritus, its response to therapy and its burden in psoriasis remain to be better characterized. OBJECTIVE: To investigate characteristics and burden of pruritus in an international cohort of patients with psoriasis. METHODS: This cross-sectional study included a total of 634 patients and 246 controls from Germany, Poland and Russia. Physicians examined and interviewed participants, recording clinical characteristics, such as severity, therapy and localization of psoriatic lesions. Participants filled out self-reported questionnaires including questions on pruritus severity and impact, characteristics, and response to therapy, and quality of life (QoL). Localization patterns of pruritus and skin lesions were visualized using body heat maps. RESULTS: Most patients (82%) experienced pruritus throughout their disease, and 75% had current pruritus. The majority of patients (64%) perceived pure pruritus, and those who reported additional painful and/or burning sensations (36%) reported overall stronger pruritus. The scalp was the most frequently reported localization of pruritus, even in the absence of skin lesions. Body surface area (BSA) of pruritus was not linked to pruritus intensity, but to BSA of psoriatic lesions (rho = 0.278; P < 0.001). One third of patients (31%) reported impaired sex-life, and 4% had suicidal ideations due to pruritus. In up to one third of patients, psoriasis therapies had little or no effect on pruritus. The only therapeutic option offered to some of these patients were antihistamines, which appeared to be effective in most cases. CONCLUSION: Pruritus is highly prevalent in psoriasis and is linked to a significant burden. Current psoriasis therapies are frequently insufficient to control pruritus. Managing psoriasis should include the assessment and control of itch. Efficient antipruritic therapies should be developed and be made available for patients with psoriasis.

A possible role of DNA methylation in functional divergence of a fast evolving duplicate gene encoding odorant binding protein 11 in the honeybee.

Although gene duplication is seen as the main path to evolution of new functions, molecular mechanisms by which selection favours the gain versus loss of newly duplicated genes and minimizes the fixation of pseudo-genes are not well understood. Here, we investigate in detail a duplicate honeybee gene obp11 belonging to a fast evolving insect gene family encoding odorant binding proteins (OBPs). We report that obp11 is expressed only in female bees in rare antennal sensilla basiconica in contrast to its tandem partner obp10 that is expressed in the brain in both females and males (drones). Unlike all other obp genes in the honeybee, obp11 is methylated suggesting that functional diversification of obp11 and obp10 may have been driven by an epigenetic mechanism. We also show that increased methylation in drones near one donor splice site that correlates with higher abundance of a transcript variant encoding a truncated OBP11 protein is one way of controlling its contrasting expression. Our data suggest that like in mammals and plants, DNA methylation in insects may contribute to functional diversification of proteins produced from duplicated genes, in particular to their subfunctionalization by generating complementary patterns of expression.

EGFR gene methylation is not involved in Royalactin controlled phenotypic polymorphism in honey bees.

The 2011 highly publicised Nature paper by Kamakura on honeybee phenotypic dimorphism, (also using Drosophila as an experimental surrogate), claims that a single protein in royal jelly, Royalactin, essentially acts as a master "on-off" switch in development via the epidermal growth factor receptor (AmEGFR), to seal the fate of queen or worker. One mechanism proposed in that study as important for the action of Royalactin is differential amegfr methylation in alternate organismal outcomes. According to the author differential methylation of amegfr was experimentally confirmed and shown in a supportive figure. Here we have conducted an extensive analysis of the honeybee egfr locus and show that this gene is never methylated. We discuss several lines of evidence casting serious doubts on the amegfr methylation result in the 2011 paper and consider possible origins of the author's statement. In a broader context, we discuss the implication of our findings for contrasting context-dependent regulation of EGFR in three insect species, Apis mellifera, D. melanogaster and the carpenter ant, Camponotus floridanus, and argue that more adequate methylation data scrutiny measures are needed to avoid unwarranted conclusions.

Common variants of ZNF750, RPTOR and TRAF3IP2 genes and psoriasis risk.

Psoriasis vulgaris is a genetically heterogenous disease with unclear molecular background. We assessed the association of psoriasis and its main clinical phenotypes with common variants of three potential psoriasis susceptibility genes: ZNF750, RPTOR and TRAF31P2. We genotyped 10 common variants in a cohort of 1,034 case-control individuals using Taqman genotyping assays and sequencing. Minor alleles of all four TRAF3IP2 variants were more frequent among cases. The strongest, significant association was observed for rs33980500 (OR = 2.5, p = 0.01790). Minor allele of this SNP was always present in two haplotypes found to be associated with increased psoriasis risk: rs13196377_G + rs13190932_G + rs33980500_T + rs13210247_A (OR = 2.7, p = 0.0054) and rs13196377_A + rs13190932_A + rs33980500_T + rs13210247_G (OR = 1.8, p = 0.0008). Analyses of clinically relevant phenotypes revealed association of rs33980500 with pustular psoriasis (OR = 1.2, p = 0.0109). We observed significant connection of severity of cutaneous disease with variation at rs13190932 and suggestive with three remaining TRAF3IP2 SNPs. Another positive associations were found between age of onset and familial aggregation of disease: smoking and younger age of onset, smoking and occurrence of pustular psoriasis, nail involvement and arthropatic psoriasis, nail involvement and more severe course of psoriasis. We found no statistically significant differences in the prevalence of the examined variants of RPTOR and ZNF750 genes among our cases and controls. We have replicated the association of TRAF3IP2-_rs33980500 variant with the susceptibility to psoriasis. We have found new associations with clinically relevant subphenotypes such as pustular psoriasis or moderate-to-severe cases. We ascertain no connection of RPTOR and ZNF750 variants with psoriasis or its subphenotypes.

Xeroderma pigmentosum genes and melanoma risk.

Xeroderma pigmentosum is a rare autosomal recessive disease that is associated with a severe deficiency in nucleotide excision repair. The presence of a distinct the nucleotide excision repair (NER) mutation signature in melanoma suggests that perturbations in this critical repair process are likely to be involved with disease risk. We hypothesized that persons with polymorphic NER gene(s) are likely to have reduced NER activity and are consequently at an increased risk of melanoma development. We assessed the association between 94 SNPs within seven XP genes (XPA-XPG) and the melanoma risk in the Polish population. We genotyped 714 unselected melanoma patients and 1,841 healthy adults to determine if there were any polymorphisms differentially represented in the disease group. We found that a significantly decreased risk of melanoma was associated with the Xeroderma pigmentosum complementation (XPC) rs2228000_CT genotype (odds ratio [OR] = 0.15; p < 0.001) and the rs2228000_TT genotype (OR = 0.11; p < 0.001) compared to the reference genotype. Haplotype analysis within XPC revealed the rs2228001_A + G1475A_G + G2061A_A + rs2228000_T + rs3731062_C haplotype (OR = 0.26; p < 0.05) was associated with a significantly decreased disease risk. The haplotype analysis within the Xeroderma pigmentosum group D (XPD) showed a modest association between two haplotypes and a decrease in melanoma risk. There were no major differences between the prevalence of the XP polymorphisms among young or older patients with melanoma. Linkage disequilibrium of XPC: rs2228001, G1475A, G2061A, rs2228000 and rs3731062 was found. The data from our study support the notion that only XPC and XPD genes are associated with melanoma susceptibility.

DNA methylation changes elicited by social stimuli in the brains of worker honey bees.

Social environments are notoriously multifactorial, yet studies in rodents have suggested that single variables such as maternal care can in fact be disentangled and correlated with specific DNA methylation changes. This study assesses whether non-detrimental social environmental variation in a highly plastic social insect is correlated with epigenomic modifications at the DNA methylation level. Honey bee workers perform tasks such as nursing and foraging in response to the social environment in the hive, in an age-linked but not age-dependent manner. In this study, the methylation levels of 83 cytosine-phosphate-guanosine dinucleotides over eight genomic regions were compared between the brains of age-matched bees performing nursing or foraging tasks. The results reveal more changes correlated with task than with chronological age, and also hive-associated methylation at some sites. One methylation site from a gene encoding Protein Kinase C binding protein 1 was consistently more methylated in foragers than nurses, which is suggested to lead to production of task-specific protein isoforms via alternative splicing. This study illustrates the ability of the neural epigenome to dynamically respond to complex social stimuli.

Vitamin D receptor variants and the malignant melanoma risk: a population-based study.

BACKGROUND: There is continuing interest in identifying low-penetrance genes which are associated with an increased susceptibility to common types of cancer, including malignant melanoma. METHODS: We sought to examine the association between four VDR common variants (rs1544410, rs731236, rs10735810, rs4516035) and the risk of melanoma in the Polish population. We also determined the prevalence of compound carriers of VDR and known MM genetic risk factors MC1R and CDKN2A (A148T) variants. We examined 763 unselected melanoma cases, 763 healthy adults matched for sex and age with the melanoma cases and 777 newborns. RESULTS: None of the VDR variants alone or as compound carriers of two or more of the VDR genotypes were associated with MM risk. There were no major differences between the prevalences of the examined variants among patients with MM on UV-exposed and UV-non exposed skin areas, as well as among early-onset and late-onset cases. We found no association between VDR and MC1R or between VDR and CDKN2A common variants. A statistically significant over-representation of one VDR haplotype: rs731236_A+rs1544410_T (OR=3.2, p=0.02) was detected. Linkage disequilibrium of rs1544410 and rs731236 was confirmed. CONCLUSION: To answer the question, whether VDR can be regarded as melanoma susceptibility gene, additional, large multi-center association studies have to be performed.

Rowell's syndrome in the course of treatment with sodium valproate: a case report and review of the literature data.

Rowell's syndrome (RS) is a rare type of coexistence of one of the lupus erythematosus (LE) types (systemic, subacute cutaneous or discoid) and erythema multiforme (EM) (including toxic epidermal necrolysis). We present the case of a 51-year-old patient with a diagnosis of RS, most probably caused by drugs given as psychiatric treatment. After cessation of sodium valproate and initiation of treatment with prednisolone, a spectacular clinical remission was achieved. The likely role of psychiatric drugs, namely sodium valproate and sertraline, as triggering factors, is discussed.

Nutritional control of reproductive status in honeybees via DNA methylation.

Fertile queens and sterile workers are alternative forms of the adult female honeybee that develop from genetically identical larvae following differential feeding with royal jelly. We show that silencing the expression of DNA methyltransferase Dnmt3, a key driver of epigenetic global reprogramming, in newly hatched larvae led to a royal jelly-like effect on the larval developmental trajectory; the majority of Dnmt3 small interfering RNA-treated individuals emerged as queens with fully developed ovaries. Our results suggest that DNA methylation in Apis is used for storing epigenetic information, that the use of that information can be differentially altered by nutritional input, and that the flexibility of epigenetic modifications underpins, profound shifts in developmental fates, with massive implications for reproductive and behavioral status.

Genome-wide analysis of genes related to ovary activation in worker honey bees.

A defining characteristic of eusocial animals is their division of labour into reproductive and nonreproductive specialists. Here, we used a microarray study to identify genes associated with functional sterility in the worker honey bee Apis mellifera. We contrasted gene expression in workers from a functionally sterile wild-type strain with that in a mutant (anarchist) strain selected for high rates of ovary activation. We identified a small set of genes from the brain (n = 7) and from the abdomen (n = 5) that are correlated in their expression with early stages of ovary activation. Sterile wild-type workers up-regulated two unknown genes and a homologue of Drosophila CG6004. By contrast, reproductive anarchist workers up-regulated genes for the yolk protein vitellogenin, venom peptides and a member of the AdoHycase superfamily, among others. The differentially expressed genes identified are likely to be involved in early differentiation into sterile and reproductive worker phenotypes and may therefore form part of the gene networks associated with the regulation of honey bee worker sterility. Our study may have lacked sufficient power to detect all but a minority of biologically relevant changes taking place; however, the differential expression of vitellogenin and a putative AdoHycase suggests that our screen has captured core reproductive genes and that ovary activation may involve an epigenetic mechanism.

Common variants of DNA repair genes and malignant melanoma.

In the current study, we evaluated the possible associations of seven common variants of the DNA repair and cell cycle control genes BRCA2 and CHEK2 with malignant melanoma (MM). We genotyped 630 unselected MM patients and over 3700 controls (newborns, age- and sex-matched healthy adults with negative cancer family histories, and the adults selected at random by family doctors) for the prevalence of three common variants of the BRCA2 (T1915M, N991D and N372H) and four common variants of the CHEK2 (1100delC, VS2+1G --> A, I157T and del5395). Our study strongly suggests that the common variant of the BRCA2 gene -- the N991D variant is associated with malignant melanoma risk (OR=1.8, p=0.002 after Bonferroni correction). Patients homozygote for the N991D variant were present in 0.32% of cases and only 0.13% of controls. The other variants studied were not over-represented among MM patients when compared to the general population. In conclusion, we report an increased melanoma risk among carriers of the N991D change of the BRCA2 and no association of the CHEK2 changes with malignant melanoma.

Characterization of a metabotropic glutamate receptor in the honeybee (Apis mellifera): implications for memory formation.

G-protein-coupled metabotropic glutamate receptors (GPC mGluRs) are important constituents of glutamatergic synapses where they contribute to synaptic plasticity and development. Here we characterised a member of this family in the honeybee. We show that the honeybee genome encodes a genuine mGluR (AmGluRA) that is expressed at low to medium levels in both pupal and adult brains. Analysis of honeybee protein sequence places it within the type 3 GPCR family, which includes mGlu receptors, GABA-B receptors, calcium-sensing receptors, and pheromone receptors. Phylogenetic comparisons combined with pharmacological evaluation in HEK 293 cells transiently expressing AmGluRA show that the honeybee protein belongs to the group II mGluRs. With respect to learning and memory AmGluRA appears to be required for memory formation. Both agonists and antagonists selective against the group II mGluRs impair long-term (24 h) associative olfactory memory formation when applied 1 h before training, but have no effect when injected post-training or pre-testing. Our results strengthen the notion that glutamate is a key neurotransmitter in memory processes in the honeybee.

RNAi-induced phenotypes suggest a novel role for a chemosensory protein CSP5 in the development of embryonic integument in the honeybee (Apis mellifera).

Small chemosensory proteins (CSPs) belong to a conserved, but poorly understood, protein family found in insects and other arthropods. They exhibit both broad and restricted expression patterns during development. In this paper, we used a combination of genome annotation, transcriptional profiling and RNA interference to unravel the functional significance of a honeybee gene (csp5) belonging to the CSP family. We show that csp5 expression resembles the maternal-zygotic pattern that is characterized by the initiation of transcription in the ovary and the replacement of maternal mRNA with embryonic mRNA. Blocking the embryonic expression of csp5 with double-stranded RNA causes abnormalities in all body parts where csp5 is highly expressed. The treated embryos show a "diffuse", often grotesque morphology, and the head skeleton appears to be severely affected. They are 'unable-to-hatch' and cannot progress to the larval stages. Our findings reveal a novel, essential role for this gene family and suggest that csp5 (unable-to-hatch) is an ectodermal gene involved in embryonic integument formation. Our study confirms the utility of an RNAi approach to functional characterization of novel developmental genes uncovered by the honeybee genome project and provides a starting point for further studies on embryonic integument formation in this insect.

Novel cuticular proteins revealed by the honey bee genome.

With the completion of the honey bee genome project, a transition is now occurring from the acquisition of gene sequence to understanding the role and context of gene products within the genome. Here we annotated and characterised a cluster of three genes in a GC-rich 11 kb genomic region on the linkage group 4 encoding highly hydrophobic polypeptides (named apidermins; APD 1-3) containing both sequence motifs characteristic of cuticular proteins and distinctly novel features. Five amino acids, Ala, Gly, Leu, Pro and Val, account for 74-86% of their respective sequences with Ala being the most abundant residue (at least 30% of each peptide). A conserved tetra-peptide AAPA/V is found in all three proteins, but none has the 'R and R' signature implicated in chitin binding. Two proteins, APD-1 and APD-2, contain an arginine-rich motif RERR in short non-hydrophobic stretches near the N-terminal of mature proteins and in both proteins tryptophan is the C-terminal residue. All three genes are spliced and highly expressed in a defined spatio-temporal pattern. apd-1 is expressed in the exoskeletal epidermis, but only during a restricted period of a few days of late pupal and early adult life when the cuticle becomes dark. APD2 appears to be a protein of "internal" cuticles and is expressed in the tracheas, oesophagus and stomach, and also in the embryo. The expression of apd-3 partly overlaps with both apd-1 and apd-3, but apd-3 also is uniquely associated with non-pigmented cuticles such as the eye cover and external cuticle of white pupae. This study expands the collection of genes encoding cuticular proteins by three novel and well characterised members.

Towards a molecular definition of worker sterility: differential gene expression and reproductive plasticity in honey bees.

We show that differences in the reproductive development of honey bee workers are associated with locus-specific changes to abundance of messenger RNA. Using a cross-fostering field experiment to control for differences related to age and environment, we compared the gene expression profiles of functionally sterile workers (wild-type) and those from a mutant strain in which workers are reproductively active (anarchist). Among the set of three genes that are significantly differentially expressed are two major royal jelly proteins that are up-regulated in wild-type heads. This discovery is consistent with sterile workers synthesizing royal jelly as food for developing brood. Likewise, the relative underexpression of these two royal jellies in anarchist workers is consistent with these workers' characteristic avoidance of alloparental behaviour, in favour of selfish egg-laying. Overall, there is a trend for the most differentially expressed genes to be up-regulated in wild-type workers. This pattern suggests that functional sterility in honey bee workers may generally involve the expression of a suite of genes that effectively 'switch' ovaries off, and that selfish reproduction in honey bee workers, though rare, is the default developmental pathway that results when ovary activation is not suppressed.

Carbohydrate metabolism genes and pathways in insects: insights from the honey bee genome.

Carbohydrate-metabolizing enzymes may have particularly interesting roles in the honey bee, Apis mellifera, because this social insect has an extremely carbohydrate-rich diet, and nutrition plays important roles in caste determination and socially mediated behavioural plasticity. We annotated a total of 174 genes encoding carbohydrate-metabolizing enzymes and 28 genes encoding lipid-metabolizing enzymes, based on orthology to their counterparts in the fly, Drosophila melanogaster, and the mosquito, Anopheles gambiae. We found that the number of genes for carbohydrate metabolism appears to be more evolutionarily labile than for lipid metabolism. In particular, we identified striking changes in gene number or genomic organization for genes encoding glycolytic enzymes, cellulase, glucose oxidase and glucose dehydrogenases, glucose-methanol-choline (GMC) oxidoreductases, fucosyltransferases, and lysozymes.

XPD common variants and their association with melanoma and breast cancer risk.

There are suggestions in the literature that common variants in the XPD gene may be associated with an altered risk of melanoma and breast cancer. To establish if the XPD common variants Asp312Asn and Lys751Gln are associated with an increased melanoma or breast cancer risk we performed an association study based on genotyping 426 unselected patients with malignant melanoma (MM) and 1830 consecutive breast cancer cases and compared the results to 1262 geographically matched newborns, 621 adults from the region of Szczecin (unselected for age and cancer family history), 421 healthy adults age- and sex-matched with the melanoma cases and 511 healthy controls matched with the breast cancer patients from the region of Szczecin. Additionally we examined the prevalence of three additional XPD variants, Gly156Gly, Leu485Pro and Arg112His amongst the 421 unselected melanoma patients. All of the variants when evaluated singularly were found not to be associated either with melanoma or breast cancer risk in younger or older patients. A modest association was observed with breast cancer risk when the Lys751Gln_CC/Asp312Asn_AA genotype (OR=1.5, p<0.05) segregated together. Individuals harboring the Lys751Gln_CC/Gly156Gly_CC genotype were significantly over-represented among late-onset melanoma cases (OR=1.7, p<0.05). The results of analyses of linkage disequilibrium and haplotype frequency support the thesis that a combination of at least two SNPs (Lys751Gln_CC/Gly156Gly_CC or Lys751Gln_CC/Asp312Asn_AA) inherited as a haplotype was associated with disease. These two pairs of SNPs could therefore be regarded as a single hereditary unit that would have a very small probability of being disrupted by recombination. Additional studies are required to determine whether these particular changes can be associated with an increased risk of other malignancies at different sites of origin.

Effects of caffeine on olfactory and visual learning in the honey bee (Apis mellifera).

Although caffeine is known to improve alertness and arousal in humans and other mammals, its impacts on specific behaviours, including complex cognitive processes, remain controversial. We reasoned that the availability of an easily manipulable, but behaviourally complex invertebrate organism with a simpler nervous system would be beneficial to this field of research. We used a popular behavioural model, the honeybee, to evaluate the effects of caffeine on (1) the development of olfactory learning and (2) the performance in complex learning paradigms, including a 'delayed-match-to-sample' task and visual associative learning. To evaluate the efficacy of caffeine treatment, a variety of doses (0.4-400 ng/1 mg of body mass) were applied topically to tethered individuals. Behavioural testing was performed with either tethered or free-flying adult honeybees. We show that caffeine has marked cognitive effects in this species. In young honeybees, it reduces the age at which restrained individuals are able to learn an olfactory associative task, whereas in older, free-flying bees, caffeine improves both motivation and cognitive performance in complex learning tasks. Our results suggest that the honeybee model may be useful in explaining caffeine-related behavioural changes not only in this species, but also in mammalian systems.