Ectodysplasin is released by proteolytic shedding and binds to the EDAR protein

Anhidrotic ectodermal dysplasia (EDA) is an X-linked disorder characterized by abnormal development of ectoderm and its appendices. The EDA gene encodes different isoforms of ectodysplasin, a transmembrane protein. The two longest isoforms, ectodysplasin-A1 and -A2, which differ by an insertion of two amino acids, are trimeric type II membrane proteins with an extracellular portion containing a short collagenous domain and a TNF ligand motif in the C-terminal region. We show that ectodysplasin is released from cells to the culture medium. Deletion constructs were used to localize the cleavage site and show that the putative recognition sequence of a furin-like enzyme is needed for the cleavage. Some EDA patients have missense mutations affecting this recognition sequence, suggesting that cleavage has biological significance in vivo. EDAR, a recently cloned member of the TNFR family and the product of the downless gene, is able to co-precipitate ectodysplasin, confirming that they form a ligand-receptor pair. In situ hybridization and immunostaining studies show that ectodysplasin and EDAR are expressed in adjacent or partially overlapping layers in the developing human skin. We conclude that as a soluble ligand, ectodysplasin is able to interact with EDAR and mediate signals needed for the development of ectodermal appendages.     

Abnormalities of chromosomes 7 and 22 in human malignant pleural mesothelioma: correlation between Southern blot and cytogenetic analyses.

Southern blot hybridization studies were performed on 23 mesothelioma primary tumor specimens to detect chromosome 1-, 7-, and 22-specific numerical changes, gene amplifications, and gene rearrangements. The molecular findings were compared with previous cytogenetic findings. No gene rearrangements or amplifications were detected. A numerical abnormality of chromosome 7 was detected by Southern blot analysis in two cases in which no numerical abnormality had been detected by the previous chromosome study. A numerical aberration of chromosome 22 was detected in five cases, which was compatible with the cytogenetic finding of monosomy 22 in these cases. The Southern blot results for the copy numbers of chromosomes 7 and 22 were concordant with the cytogenetic findings in 65%-80% of the cases.     

Characterization of GPRA, a novel G protein-coupled receptor related to asthma

We recently identified a novel positional asthma susceptibility gene, GPRA, which belongs to the G protein-coupled receptor family. In the present studies, we show that isoform specific activation of GPRA-A with its agonist, Neuropeptide S (NPS) resulted in significant inhibition of cell growth. GPRA has several variants due to extensive alternative splicing. We observed that only the full-length variants, GPRA-A and GPRA-B, with 7 transmembrane topology are transported into the plasma membrane, while the truncated proteins retain intracellular compartments. To clarify disease mechanism, we studied co-expression of the variants without finding any indication that truncated variants would inhibit the receptor transport into the plasma membrane. By using in situ hybridization and immunohistochemistry, we detected ubiquitous expression of GPRA-B, and frequent expression of GPRA-A in the epithelia of several organs including bronchi and gastrointestinal tract. Furthermore, we observed aberrant mRNA and protein expression levels of GPRA in the asthmatic bronchi. Finally, we demonstrate that GPRA and NPS are co-expressed in bronchial epithelium. In summary, this study provides evidence that GPRA might have functional relevance in modulating asthma by increased expression levels in the relevant tissues under diseased state and by potential inhibitory effect of GPRA-A activation on cell growth.     

Coding haplotype analysis supports HCR as the putative susceptibility gene for psoriasis at the MHC PSORS1 locus

PSORS1, near HLA-C, is the major genetic determinant of psoriasis. We present genetic and structural evidence suggesting a major role for the HCR gene at the PSORS1 locus. Genotyping of 419 families from six populations revealed that coding single-nucleotide polymorphisms of HCR formed a conserved allele HCR*WWCC that associated highly significantly with psoriasis and with the HLA-Cw6 allele in all populations. Because of strong linkage disequilibrium between HLA-Cw6 and HCR*WWCC, the two genes could not be genetically distinguished by this sample size. However, the variant HCR allele was predicted to differ in secondary structure from the wild-type protein. HCR protein expression in lesional psoriatic skin differed considerably from that observed in normal skin. These results provide strong evidence for the HCR*WWCC allele as a major genetic determinant for psoriasis, probably by a mechanism impacting on keratinocyte proliferation.     

Working memory brain activity and capacity link MAOA polymorphism to aggressive behavior during development

A developmental increase in working memory capacity is an important part of cognitive development, and low working memory (WM) capacity is a risk factor for developing psychopathology. Brain activity represents a promising endophenotype for linking genes to behavior and for improving our understanding of the neurobiology of WM development. We investigated gene–brain–behavior relationships by focusing on 18 single-nucleotide polymorphisms (SNPs) located in six dopaminergic candidate genes (COMT, SLC6A3/DAT1, DBH, DRD4, DRD5, MAOA). Visuospatial WM (VSWM) brain activity, measured with functional magnetic resonance imaging, and VSWM capacity were assessed in a longitudinal study of typically developing children and adolescents. Behavioral problems were evaluated using the Child Behavior Checklist (CBCL). One SNP (rs6609257), located ∼6.6 kb downstream of the monoamine oxidase A gene (MAOA) on human chromosome X, significantly affected brain activity in a network of frontal, parietal and occipital regions. Increased activity in this network, but not in caudate nucleus or anterior prefrontal regions, was correlated with VSWM capacity, which in turn predicted externalizing (aggressive/oppositional) symptoms, with higher WM capacity associated with fewer externalizing symptoms. There were no direct significant correlations between rs6609257 and behavioral symptoms. These results suggest a mediating role of WM brain activity and capacity in linking the MAOA gene to aggressive behavior during development.     

α2-Heremans–Schmid glycoprotein gene polymorphisms are associated with adipocyte insulin action

Aims/hypothesis The aim of this study was to investigate the effect of single-nucleotide polymorphisms (SNPs) in the gene encoding the human ₂-Heremans–Schmid glycoprotein (AHSG) on obesity and insulin action in adipocytes.Methods We screened 24 individuals for SNPs in AHSG. Six haplotype-tagging SNPs were genotyped in 188 lean and 176 obese otherwise healthy women for whom common blood chemistry phenotypes were also available. Adipocyte lipolysis and lipogenesis phenotypes were quantified in a subset of 117 lean and 174 obese women.Results The –469T>G SNP, which is located in the 5 region of AHSG, was associated with insulin-mediated inhibition of lipolysis and stimulation of lipogenesis, as well as basal and 8-bromocyclic AMP-stimulated lipolysis. Three AHSG SNPs were associated with circulating levels of cholesterol. None of the six genotyped SNPs or inferred haplotypes were associated with BMI, calculated percent body fat, waist circumference, circulating levels of glucose or insulin, or homeostasis model assessment of insulin resistance, which was used as an estimate of in vivo insulin sensitivity.Conclusions/interpretation Our results are in agreement with a threshold model of susceptibility for insulin resistance and type 2 diabetes, in which specific genetic loci regulate intermediate molecular phenotypes. When an individuals set of susceptibility alleles at such loci exceeds a threshold, clinical disease occurs. Lipolysis in adipocytes appears to be a phenotype that is particularly sensitive to variation in AHSG.     

The human GIMAP5 gene has a common polyadenylation polymorphism increasing risk to systemic lupus erythematosus

Background

Several members of the GIMAP gene family have been suggested as being involved in different aspects of the immune system in different species. Recently, a mutation in the GIMAP5 gene was shown to cause lymphopenia in a rat model of autoimmune insulin‐dependent diabetes. Thus it was hypothesised that genetic variation in GIMAP5 may be involved in susceptibility to other autoimmune disorders where lymphopenia is a key feature, such as systemic lupus erythematosus (SLE).

Material and methods

To investigate this, seven single nucleotide polymorphisms in GIMAP5 were analysed in five independent sets of family‐based SLE collections, containing more than 2000 samples.

Result

A significant increase in SLE risk associated with the most common GIMAP5 haplotype was found (OR 1.26, 95% CI 1.02 to 1.54, p = 0.0033). In families with probands diagnosed with trombocytopenia, the risk was increased (OR 2.11, 95% CI 1.09 to 4.09, p = 0.0153). The risk haplotype bears a polymorphic polyadenylation signal which alters the 3′ part of GIMAP5 mRNA by producing an inefficient polyadenylation signal. This results in higher proportion of non‐terminated mRNA for homozygous individuals (p<0.005), a mechanism shown to be causal in thalassaemias. To further assess the functional effect of the polymorphic polyadenylation signal in the risk haplotype, monocytes were treated with several cytokines affecting apoptosis. All the apoptotic cytokines induced GIMAP5 expression in two monocyte cell lines (1.5–6 times, p<0.0001 for all tests).

Conclusion

Taken together, the data suggest the role of GIMAP5 in the pathogenesis of SLE.     

Triadic Interactions in MIECHV: Relations to Home Visit Quality

Objectives This study was conducted to look inside home visits to examine active intervention ingredients used and their relations with ratings of home visit quality. In particular, triadic interactions that engage the home visitor, parent, and child together and provide a context for home visitors to facilitate parent-child interactions by observing, modeling and coaching behaviors that promote optimal child development were examined. Methods Observations were conducted to describe intervention activities (with the HVOF-R) and rate quality of home visit practices and engagement (with the HOVRS A+). Results Analyses revealed the majority of home visit time (71%) was spent in home visitor-parent interactions with only a small proportion of home visit time (17%) spent in triadic interactions and an even smaller proportion of time (2%) during which home visitors actively coached parent-child interactions. Amount of time spent in triadic interactions was related positively to quality ratings of home visit practices and engagement. Moreover, time spent coaching parent-child interactions uniquely predicted home visit quality after accounting for visit length and home visitor time spent observing and modeling. Conclusions for Practice Increasing the percentage of home visitors engage the parent and child in triadic interaction should be a focus for home visiting programs. Home visitors will likely need professional development and supervisory support to enhance their skills in coaching parent-child interactions during triadic interactions.