Targeting TL1A/DR3 Signaling Offers a Therapeutic Advantage to Neutralizing IL13/IL4Rα in Muco-Secretory Fibrotic Disorders

Mucus secretion is an important feature of asthma that highly correlates with morbidity. Current therapies, including administration of mucolytics and anti-inflammatory drugs, show limited effectiveness and durability, underscoring the need for novel effective and longer lasting therapeutic approaches. Here we show that mucus production in the lungs is regulated by the TNF superfamily member 15 (TL1A) acting through the mucus-inducing cytokine IL-13. TL1A induces IL13 expression by innate lymphoid cells leading to mucus production, in addition to promoting airway inflammation and fibrosis. Reciprocally, neutralization of IL13 signaling through its receptor (IL4Rα), completely reverses TL1A-induced mucus secretion, while maintaining airway inflammation and fibrosis. Importance of TL1A is further demonstrated using a preclinical asthma model induced by chronic house dust mite exposure where TL1A neutralization by genetic deletion or antagonistic blockade of its receptor DR3 protected against mucus production and fibrosis. Thus, TL1A presents a promising therapeutic target that out benefits IL13 in reversing mucus production, airway inflammation and fibrosis, cardinal features of severe asthma in humans.

Assessment of differentially methylated loci in individuals with end-stage kidney disease attributed to diabetic kidney disease: an exploratory study

BACKGROUND

A subset of individuals with type 1 diabetes mellitus (T1DM) are predisposed to developing diabetic kidney disease (DKD), the most common cause globally of end-stage kidney disease (ESKD). Emerging evidence suggests epigenetic changes in DNA methylation may have a causal role in both T1DM and DKD. The aim of this exploratory investigation was to assess differences in blood-derived DNA methylation patterns between individuals with T1DM-ESKD and individuals with long-duration T1DM but no evidence of kidney disease upon repeated testing to identify potential blood-based biomarkers. Blood-derived DNA from individuals (107 cases, 253 controls and 14 experimental controls) were bisulphite treated before DNA methylation patterns from both groups were generated and analysed using Illumina's Infinium MethylationEPIC BeadChip arrays (n = 862,927 sites). Differentially methylated CpG sites (dmCpGs) were identified (false discovery rate adjusted p ≤ × 10^-8 and fold change ± 2) by comparing methylation levels between ESKD cases and T1DM controls at single site resolution. Gene annotation and functionality was investigated to enrich and rank methylated regions associated with ESKD in T1DM.

RESULTS

Top-ranked genes within which several dmCpGs were located and supported by functional data with methylation look-ups in other cohorts include: AFF3, ARID5B, CUX1, ELMO1, FKBP5, HDAC4, ITGAL, LY9, PIM1, RUNX3, SEPTIN9 and UPF3A. Top-ranked enrichment pathways included pathways in cancer, TGF-β signalling and Th17 cell differentiation.

CONCLUSIONS

Epigenetic alterations provide a dynamic link between an individual's genetic background and their environmental exposures. This robust evaluation of DNA methylation in carefully phenotyped individuals has identified biomarkers associated with ESKD, revealing several genes and implicated key pathways associated with ESKD in individuals with T1DM.

Multi-cell type gene coexpression network analysis reveals coordinated interferon response and cross-cell type correlations in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an incurable autoimmune disease disproportionately affecting women. A major obstacle in finding targeted therapies for SLE is its remarkable heterogeneity in clinical manifestations as well as in the involvement of distinct cell types. To identify cell-specific targets as well as cross-correlation relationships among expression programs of different cell types, we here analyze six major circulating immune cell types from SLE patient blood. Our results show that presence of an interferon response signature stratifies patients into two distinct groups (IFNneg vs. IFNpos). Comparing these two groups using differential gene expression and differential gene coexpression analysis, we prioritize a relatively small list of genes from classical monocytes including two known immune modulators: TNFSF13B/BAFF (target of belimumab, an approved therapeutic for SLE) and IL1RN (the basis of anakinra, a therapeutic for rheumatoid arthritis). We then develop a multi-cell type extension of the weighted gene coexpression network analysis (WGCNA) framework, termed mWGCNA. Applying mWGCNA to RNA-seq data from six sorted immune cell populations (15 SLE, 10 healthy donors), we identify a coexpression module with interferon-stimulated genes (ISGs) among all cell types and a cross-cell type correlation linking expression of specific T helper cell markers to B cell response as well as to TNFSF13B expression from myeloid cells, all of which in turn correlates with disease severity of IFNpos patients. Our results demonstrate the power of a hypothesis-free and data-driven approach to discover drug targets and to reveal novel cross-correlation across cell types in SLE with implications for other autoimmune diseases.

Comparison of methylation patterns generated from genomic and cell-line derived DNA using the Illumina Infinium MethylationEPIC BeadChip array

Objectives

Genomic DNA (gDNA) is the optimal source of DNA for methylation analysis. This study compared methylation patterns in gDNA derived from blood with cell-line derived DNA (clDNA) from the same individuals. The clDNA had been generated via an Epstein-Barr virus transformation of the participant’s lymphocytes. This analysis sought to determine whether clDNA has the potential to be utilised in lieu of finite/unavailable gDNA in methylation analyses using Illumina Infinium MethylationEPIC BeadChip arrays that assess 862,927 CpG sites.

Results

DNA samples were divided into two groups with eight gDNA and eight matched clDNA samples compared in each group (n = 16 individuals with 32 samples in total). Methylation patterns for gDNA samples generated for both groups were compared to the clDNA equivalent samples using Partek^® Genomics Suite^® to assess whether the significantly different CpG sites were consistent between both groups. In total, 28,632 CpG sites with significantly different levels of methylation (p < ×10⁻⁸) were common to both groups while 828,072 CpG sites assessed by the MethylationEPIC array were not significantly different in either group. This indicates that there is potential for clDNA to be used as a replacement for finite gDNA samples when absolutely necessary in DNA methylation studies.

Proteomic and metabolomic approaches in the search for biomarkers in chronic kidney disease

Chronic kidney disease (CKD) is an aging-related disorder that represents a major global public health burden. Current biochemical biomarkers, such as serum creatinine and urinary albumin, have important limitations when used to identify the earliest indication of CKD or in tracking the progression to more advanced CKD. These issues underline the importance of finding and testing new molecular biomarkers that are capable of successfully meeting this clinical need. The measurement of changes in nature and/or levels of proteins and metabolites in biological samples from patients provide insights into pathophysiological processes. Proteomic and metabolomic techniques provide opportunities to record dynamic chemical signatures in patients over time. This review article presents an overview of the recent developments in the fields of metabolomics and proteomics in relation to CKD. Among the many different proteomic biomarkers proposed, there is particular interest in the CKD273 classifier, a urinary proteome biomarker reported to predict CKD progression and with implementation potential. Other individual non-invasive peptidomic biomarkers that are potentially relevant for CKD detection include type 1 collagen, uromodulin and mucin-1. Despite the limited sample sizes and variability of the metabolomics studies, some metabolites such as trimethylamine N-oxide, kynurenine and citrulline stand out as potential biomarkers in CKD.

Analysis of single nucleotide polymorphisms implicate mTOR signalling in the development of new-onset diabetes after transplantation

Introduction

Despite excellent first year outcomes in kidney transplantation, there remain significant long-term complications related to new-onset diabetes after transplantation (NODAT). The purpose of this study was to validate the findings of previous investigations of candidate gene variants in patients undergoing a protocolised, contemporary immunosuppression regimen, using detailed serial biochemical testing to identify NODAT development.

Methods

One hundred twelve live and deceased donor renal transplant recipients were prospectively followed-up for NODAT onset, biochemical testing at days 7, 90, and 365 after transplantation. Sixty-eight patients were included after exclusion for non-white ethnicity and pre-transplant diabetes. Literature review to identify candidate gene variants was undertaken as described previously.

Results

Over 25% of patients developed NODAT. In an adjusted model for age, sex, BMI, and BMI change over 12 months, five out of the studied 37 single nucleotide polymorphisms (SNPs) were significantly associated with NODAT: rs16936667:PRDM14 OR 10.57;95% CI 1.8–63.0;p = 0.01, rs1801282:PPARG OR 8.5; 95% CI 1.4–52.7; p = 0.02, rs8192678:PPARGC1A OR 0.26; 95% CI 0.08–0.91; p = 0.03, rs2144908:HNF4A OR 7.0; 95% CI 1.1–45.0;p = 0.04 and rs2340721:ATF6 OR 0.21; 95%CI 0.04–1.0; p = 0.05.

Conclusion

This study represents a replication study of candidate SNPs associated with developing NODAT and implicates mTOR as the central regulator via altered insulin sensitivity, pancreatic β cell, and mitochondrial survival and dysfunction as evidenced by the five SNPs.

General significance

1)

Highlights the importance of careful biochemical phenotyping with oral glucose tolerance tests to diagnose NODAT in reducing time to diagnosis and missed cases.

2)

This alters potential genotype:phenotype association.

3)

The replication study generates the hypothesis that mTOR signalling pathway may be involved in NODAT development.

•

Oral glucose tolerance tests reduce time to NODAT diagnosis and missed cases

•

Biochemical testing changes genotype:phenotype association

•

mTOR signalling pathway may be involved in NODAT development

Genetic risk factors affecting mitochondrial function are associated with kidney disease in people with Type 1 diabetes

AIM

To evaluate the association with diabetic kidney disease of single nucleotide polymorphisms (SNPs) that may contribute to mitochondrial dysfunction.

METHODS

The mitochondrial genome and 1039 nuclear genes that are integral to mitochondrial function were investigated using a case (n = 823 individuals with diabetic kidney disease) vs. control (n = 903 individuals with diabetes and no renal disease) approach. All people included in the analysis were of white European origin and were diagnosed with Type 1 diabetes before the age of 31 years. Replication was conducted in 5093 people with similar phenotypes to those of the discovery collection. Association analyses were performed using the plink genetic analysis toolset, with adjustment for relevant covariates.

RESULTS

A total of 25 SNPs were evaluated in the mitochondrial genome, but none were significantly associated with diabetic kidney disease or end-stage renal disease. A total of 38 SNPs in nuclear genes influencing mitochondrial function were nominally associated with diabetic kidney disease and 16 SNPS were associated with end-stage renal disease, secondary to diabetic kidney disease, with meta-analyses confirming the same direction of effect. Three independent signals (seven SNPs) were common to the replication data for both phenotypes with Type 1 diabetes and persistent proteinuria or end-stage renal disease.

CONCLUSIONS

Our results suggest that SNPs in nuclear genes that influence mitochondrial function are significantly associated with diabetic kidney disease in a white European population.

Distinct methylation patterns in genes that affect mitochondrial function are associated with kidney disease in blood-derived DNA from individuals with Type 1 diabetes

AIMS

Epigenetic modifications, such as DNA methylation, can influence the risk of developing kidney disease. We studied methylation profiles in genes related to mitochondrial function to assess whether differences in these epigenetic features were associated with diabetic kidney disease in people with Type 1 diabetes.

METHODS

A case-control association study was undertaken (n = 196 individuals with diabetic kidney disease vs. n = 246 individuals without renal disease). Participants were White and diagnosed with Type 1 diabetes before 31 years of age. Genes that encode mitochondrial proteins (n = 780) were downloaded from mitoproteome.org. DNA methylation profiles from blood-derived DNA were generated using the Illumina Infinium HumanMethylation450 (262 samples) and Illumina Infinium HumanMethylation27 (192 samples) arrays. Beta values (β) were calculated and quality control was conducted, including evaluating blind duplicate DNA samples.

RESULTS

Fifty-four Cytosine-phosphate-Guanine probes across 51 unique genes were significantly associated (P ≤ 10(-8) ) with diabetic kidney disease across both the 450K and the 27K methylation arrays. A subanalysis, employing the 450K array, identified 755 Cytosine-phosphate-Guanine probes in 374 genes that were significantly associated (P ≤ 10(-8) ) with end-stage renal disease. Forty-six of the top-ranked variants for diabetic kidney disease were also identified as being differentially methylated in individuals with end-stage renal disease. The largest change in methylation (Δβ = 0.2) was observed for cg03169527 in the TAMM41 gene, chromosome 3p25.2. Three genes, PMPCB, TSFM and AUH, were observed with differential methylation at multiple Cytosine-phosphate-Guanine sites each (P < 10(-12) ).

CONCLUSIONS

Differential methylation in genes that influence mitochondrial function are associated with kidney disease in individuals with Type 1 diabetes.

Genetic and epigenetic factors influencing chronic kidney disease

Chronic kidney disease (CKD) has become a serious public health problem because of its associated morbidity, premature mortality, and attendant healthcare costs. The rising number of persons with CKD is linked with the aging population structure and an increased prevalence of diabetes, hypertension, and obesity. There is an inherited risk associated with developing CKD, as evidenced by familial clustering and differing prevalence rates across ethnic groups. Previous studies to determine the inherited risk factors for CKD rarely identified genetic variants that were robustly replicated. However, improvements in genotyping technologies and analytic methods are now helping to identify promising genetic loci aided by international collaboration and multiconsortia efforts. More recently, epigenetic modifications have been proposed to play a role in both the inherited susceptibility to CKD and, importantly, to explain how the environment dynamically interacts with the genome to alter an individual's disease risk. Genome-wide, epigenome-wide, and whole transcriptome studies have been performed, and optimal approaches for integrative analysis are being developed. This review summarizes recent research and the current status of genetic and epigenetic risk factors influencing CKD using population-based information.

Vitamin d receptor gene variants and esophageal adenocarcinoma risk: a population-based case-control study

PURPOSE

Polymorphisms in the vitamin D receptor (VDR) gene may be of etiological importance in determining cancer risk. The aim of this study was to assess the association between common VDR gene polymorphisms and esophageal adenocarcinoma (EAC) risk in an all-Ireland population-based case-control study.

METHODS

EAC cases and frequency-matched controls by age and gender recruited between March 2002 and December 2004 throughout Ireland were included. Participants were interviewed, and a blood sample collected for DNA extraction. Twenty-seven single nucleotide polymorphisms in the VDR gene were genotyped using Sequenom or TaqMan assays while the poly(A) microsatellite was genotyped by fluorescent fragment analysis. Unconditional logistic regression was applied to assess the association between VDR polymorphisms and EAC risk.

RESULTS

A total of 224 cases of EAC and 256 controls were involved in analyses. After adjustment for potential confounders, TT homozygotes at rs2238139 and rs2107301 had significantly reduced risks of EAC compared with CC homozygotes. In contrast, SS alleles of the poly(A) microsatellite had significantly elevated risks of EAC compared with SL/LL alleles. However, following permutation analyses to adjust for multiple comparisons, no significant associations were observed between any VDR gene polymorphism and EAC risk.

CONCLUSIONS

VDR gene polymorphisms were not significantly associated with EAC development in this Irish population. Confirmation is required from larger studies.

SNP in the genome-wide association study hotspot on chromosome 9p21 confers susceptibility to diabetic nephropathy in type 1 diabetes

AIMS/HYPOTHESIS

Parental type 2 diabetes mellitus increases the risk of diabetic nephropathy in offspring with type 1 diabetes mellitus. Several single nucleotide polymorphisms (SNPs) that predispose to type 2 diabetes mellitus have recently been identified. It is, however, not known whether such SNPs also confer susceptibility to diabetic nephropathy in patients with type 1 diabetes mellitus.

METHODS

We genotyped nine SNPs associated with type 2 diabetes mellitus in genome-wide association studies in the Finnish population, and tested for their association with diabetic nephropathy as well as with severe retinopathy and cardiovascular disease in 2,963 patients with type 1 diabetes mellitus. Replication of significant SNPs was sought in 2,980 patients from three other cohorts.

RESULTS

In the discovery cohort, rs10811661 near gene CDKN2A/B was associated with diabetic nephropathy. The association remained after robust Bonferroni correction for the total number of tests performed in this study (OR 1.33 [95% CI 1.14, 1.56], p = 0.00045, p (36tests) = 0.016). In the meta-analysis, the combined result for diabetic nephropathy was significant, with a fixed effects p value of 0.011 (OR 1.15 [95% CI 1.02, 1.29]). The association was particularly strong when patients with end-stage renal disease were compared with controls (OR 1.35 [95% CI 1.13, 1.60], p = 0.00038). The same SNP was also associated with severe retinopathy (OR 1.37 [95% CI 1.10, 1.69] p = 0.0040), but the association did not remain after Bonferroni correction (p (36tests) = 0.14). None of the other selected SNPs was associated with nephropathy, severe retinopathy or cardiovascular disease.

CONCLUSIONS/INTERPRETATION

A SNP predisposing to type 2 diabetes mellitus, rs10811661 near CDKN2A/B, is associated with diabetic nephropathy in patients with type 1 diabetes mellitus.

ANCA-associated vasculitis is linked to carriage of the Z allele of α₁ antitrypsin and its polymers

BACKGROUND

Small studies have linked α1 antitrypsin (α1AT) deficiency to patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV).

OBJECTIVE

To test the validity and the mechanism of this association between α1AT and AAV.

METHODS

The distribution of α1AT deficiency alleles Z and S was compared between 856 White Europeans with AAV and 1505 geographic and ethnically matched healthy controls. Genotyping was performed by allelic discrimination assay.

RESULTS

were compared between cases and controls using χ(2) tests. The serum and renal biopsies for α1AT polymers were compared using the polymer-specific 2C1 antibody. The role of α1AT polymers in promoting inflammation was investigated by examining their ability to prime neutrophils for ANCA activation as assessed by CD62L shedding, superoxide production and myeloperoxidase degranulation. Results The Z but not the S allele was over-represented in the patients compared with controls (HR=2.25, 95% CI 1.60 to 3.19). Higher concentrations of polymers of α1AT were detected in serum from patients carrying the Z allele than in those not carrying the Z allele (median (IQR) 1.40 (0.91-3.32) mg/dl vs 0.17 (0.06-0.28) mg/dl, p<0.001); polymers of α1AT were also seen in the renal biopsy of a patient with vasculitic glomerulonephritis. Polymers of α1AT primed neutrophils with CD62L shedding and increased superoxide production following ANCA activation. Carriage of the Z allele was not associated with disease severity, survival or relapse.

CONCLUSIONS

The Z but not the S deficiency allele is associated with AAV. Polymers of α1AT are present in the serum and glomeruli of at least some patients with the Z allele, which may promote inflammation through priming of neutrophils.

Association analysis of Notch pathway signalling genes in diabetic nephropathy

AIMS/HYPOTHESIS

Several studies have provided compelling evidence implicating the Notch signalling pathway in diabetic nephropathy. Co-regulation of Notch signalling pathway genes with GREM1 has recently been demonstrated and several genes involved in the Notch pathway are differentially expressed in kidney biopsies from individuals with diabetic nephropathy. We assessed single-nucleotide polymorphisms (SNPs; n = 42) in four of these key genes (JAG1, HES1, NOTCH3 and ADAM10) for association with diabetic nephropathy using a case-control design.

METHODS

Tag SNPs and potentially functional SNPs were genotyped using Sequenom or Taqman technologies in a total of 1371 individuals with type 1 diabetes (668 patients with nephropathy and 703 controls without nephropathy). Patients and controls were white and recruited from the UK and Ireland. Association analyses were performed using PLINK (http://pngu.mgh.harvard.edu/∼purcell/plink/) and haplotype frequencies in patients and controls were compared. Adjustment for multiple testing was performed by permutation testing.

RESULTS

In analyses stratified by centre, we identified six SNPs, rs8708 and rs11699674 (JAG1), rs10423702 and rs1548555 (NOTCH3), rs2054096 and rs8027998 (ADAM10) as being associated with diabetic nephropathy before, but not after, adjustment for multiple testing. Haplotype and subgroup analysis according to duration of diabetes also failed to find an association with diabetic nephropathy.

CONCLUSIONS/INTERPRETATION

Our results suggest that common variants in JAG1, HES1, NOTCH3 and ADAM10 are not strongly associated with diabetic nephropathy in type 1 diabetes among white individuals. Our findings, however, cannot entirely exclude these genes from involvement in the pathogenesis of diabetic nephropathy.

Expression and agonist responsiveness of CXCR3 variants in human T lymphocytes

The chemokine receptor CXCR3 and its ligands CXCL9, CXCL10 and CXCL11 are involved in variety of inflammatory disorders including multiple sclerosis, rheumatoid arthritis, psoriasis and sarcoidosis. Two alternatively spliced variants of the human CXCR3-A receptor have been described, termed CXCR3-B and CXCR3-alt. Human CXCR3-B binds CXCL9, CXCL10, CXCL11 as well as an additional ligand CXCL4. In contrast, CXCR3-alt only binds CXCL11. We report that CXCL4 induces intracellular calcium mobilization as well as Akt and p44/p42 extracellular signal-regulated kinase phosphorylation, in activated human T lymphocytes. These responses have similar concentration dependence and time-courses to those induced by established CXCR3 agonists. Moreover, phosphorylation of Akt and p44/p42 is inhibited by pertussis toxin, suggesting coupling to Gα(i) protein. Surprisingly, and in contrast with the other CXCR3 agonists, stimulation of T lymphocytes with CXCL4 failed to elicit migratory responses and did not lead to loss of surface CXCR3 expression. Taken together, our findings show that, although CXCL4 is coupled to downstream biochemical machinery, its role in T cells is probably distinct from that of CXCR3-A agonists.

Investigation of ACE, ACE2 and AGTR1 genes for association with nephropathy in Type 1 diabetes mellitus

BACKGROUND

Polymorphisms in ACE and AGTR1 genes have been assessed in multiple studies for association with diabetic nephropathy; however, results are conflicting. The ACE2 gene has not been studied extensively for association with diabetic nephropathy.

METHODS

We investigated variants in ACE, ACE2 and AGTR1 for association with nephropathy in a case-control group (1467 participants with Type1 diabetes, case subjects n=718; control subjects n=749) of white descent with grandparents born in the British Isles. All recruited individuals were carefully phenotyped and genotyping was performed using Sequenom, Taqman and gel electrophoresis methods. The χ(2) -test for contingency tables was used to compare genotype and allele frequencies in case and control groups.

RESULTS

No departure from Hardy-Weinberg equilibrium was observed in cases or controls. Two variants within the ACE gene (rs4293, P(allelic) =0.02, P(genotypic) =0.008; rs4309, P(allelic) =0.02, P(genotypic) =0.01) were significantly associated with nephropathy at the 5% level. No variant remained statistically significant following adjustment for multiple comparisons. No single nucleotide polymorphisms in the ACE2 or AGTR1 genes were significantly associated with nephropathy when analysed either by genotype or allele frequencies.

CONCLUSIONS

Our independent case-control study provides no evidence that common variants in ACE, ACE2 and AGTR1 play a major role in genetic susceptibility to diabetic nephropathy in a white population with Type1 diabetes.

Investigation of the association of BMP gene variants with nephropathy in Type 1 diabetes mellitus

AIMS

Diabetic nephropathy is a leading cause of end-stage renal disease. The transforming growth factor beta-bone morphogenic protein (BMP) pathway is implicated in the pathogenesis of diabetic nephropathy. The BMP2, BMP4 and BMP7 genes are located near linkage peaks for renal dysfunction, and we hypothesize that genetic polymorphisms in these biological and positional candidate genes may be risk factors for diabetic kidney disease.

METHODS

The BMP7 gene was screened, variants identified and allele frequencies determined by bidirectionally sequencing 46 individuals to facilitate selection of tag SNPs (n = 4). For BMP2 and BMP4 genes, data were downloaded for 19 single nucleotide polymorphisms (SNPs) from the International HapMap project and six tag SNPs selected.

RESULTS

The BMP7 gene was screened for novel genetic polymorphisms, haplotypes were identified, an appropriate subset of variants selected for the investigation of common genetic risk factors, and BMP2, BMP4 and BMP7 genes assessed for association with diabetic nephropathy in 1808 individuals. Thirty-two SNPs were identified, of which 11 were novel, including an amino-acid changing SNP (+63639C>T). No significant differences (P > 0.2) were observed when comparing genotype or allele or haplotype frequencies between 864 individuals with Type 1 diabetes and nephropathy compared with 944 individuals with Type 1 diabetes without nephropathy, stratified by recruitment centre.

CONCLUSIONS

Common polymorphisms in these BMP genes do not strongly influence genetic susceptibility to diabetic nephropathy in White individuals with Type 1 diabetes mellitus.

Polymorphisms of the macrophage migration inhibitory factor gene in a UK population with Type 1 diabetes mellitus

AIMS

Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine whose production is transcriptionally regulated by glucose. Experimental data from both Type 1 diabetes mellitus (T1D) patients and animal models suggests a role for MIF in the development of T1D. The aim of this study was to employ gene resequencing to identify common DNA polymorphisms in the MIF gene and subsequently assess haplotype tagged single nucleotide polymorphisms (htSNPs) using a combination of case-control and family-based association analyses in order to assess the association of MIF htSNPs with the development of T1D in a white population.

METHODS

All exons, introns and approximately 3 kb upstream and downstream of the MIF gene were screened for DNA polymorphisms in 46 individuals using DNA sequencing. Genotyping of the htSNPs was performed in 432 cases, 407 control subjects and 290 T1D parent-offspring trios, using Taqman, Sequenom, Pyrosequencing and fluorescence-based microsatellite technologies.

RESULTS

Twenty-three polymorphisms (two novel) with a minor allele frequency > 10% were identified. Four MIF htSNPs (rs875643 G>A, rs7388067 C>T, rs5844572 -/CATT, rs6003941 T>G) were identified. Allele and haplotype frequencies were similar between case and control groups (P > 0.6 by permutation test) and assessment of allele transmission distortion from informative parents to affected offspring also failed to find an association. Stratification of these analyses for age-at-onset and human leukocyte antigen (HLA)-DR risk group (DR3/DR4) did not reveal any significant associations.

CONCLUSIONS

It is unlikely that common polymorphisms in the MIF gene strongly influence susceptibility to T1D in the UK population.

Genetic polymorphisms in nitric oxide synthase 3 gene and implications for kidney disease: a meta-analysis

BACKGROUND/AIMS

The NOS3 gene is a biological and positional candidate for diabetic nephropathy. However, the relationship between NOS3 polymorphisms and renal disease is inconclusive. This study aimed to clarify the association of NOS3 variants with nephropathy in individuals with type 1 diabetes.

METHODS

We conducted a case-control study examining all common SNPs in the NOS3 gene by a tag SNP approach. Individuals with type 1 diabetes and persistent proteinuria (cases, n = 718) were compared with individuals with type 1 diabetes but no evidence of renal disease (controls, n = 749). Our replication collection comprised 1,105 individuals with type 1 diabetes recruited to a nephropathy case group and 862 control individuals with normal urinary albumin excretion rates. Meta-analysis was conducted for SNPs where more than three genotype datasets were available.

RESULTS

A novel association was identified in the discovery collection (rs1800783, p(genotype) = 0.006, p(allele) = 0.002, OR = 1.26, 95% CI: 1.08-1.47) and supported by independent replication using a tag SNP (rs4496877, pairwise r² = 0.96 with rs1800783) in the replication collection (p(genotype) = 0.002, p(allele) = 0.0006, OR = 1.27, 95% CI: 1.10-1.45).

CONCLUSION

The A allele of rs1800783 is a significant risk factor for nephropathy in individuals with type 1 diabetes, and further comprehensive studies are warranted to confirm the definitive functional variant in the NOS3 gene.

Investigation of DNA polymorphisms in SMAD genes for genetic predisposition to diabetic nephropathy in patients with type 1 diabetes mellitus

AIMS/HYPOTHESIS

SMAD proteins are involved in multiple signalling pathways and are key modulators of gene expression. We hypothesised that genetic variation in selected SMAD genes contributes to susceptibility to diabetic nephropathy.

METHODS

We selected 13 haplotype tag (ht) single nucleotide polymorphisms (SNPs) from 67 variants identified by resequencing the SMAD2 and SMAD3 genes. For SMAD1, SMAD4 and SMAD5 genes, genotype data were downloaded for 217 SNPs from Phase II of the International HapMap project. Of these, 85 SNPs met our inclusion criteria, resulting in the selection of 13 tag SNPs for further investigation. A case-control approach was employed, using 267 nephropathic patients and 442 controls with type 1 diabetes from Ireland. Two further populations (totalling 1,407 patients, 2,238 controls) were genotyped to validate initial findings. Genotyping was conducted using iPLEX, TaqMan and gel electrophoresis.

RESULTS

The distribution of genotypes was in Hardy-Weinberg equilibrium. Analysis by the chi(2) test of genotype and allele frequencies in patients versus controls in the Irish population (n = 709) revealed evidence for the association of one allele at 5% level of significance (rs10515478, p(uncorrected) = 0.006; p(corrected) = 0.04). This finding represents a relatively small difference in allele frequency of 6.4% in the patient group compared with 10.7% in the control group; this difference was not supported in subsequent investigations using DNA from European individuals with similar phenotypic characteristics.

CONCLUSIONS/INTERPRETATION

We selected an appropriate subset of variants for the investigation of common genetic risk factors and assessed SMAD1 to SMAD5 genes for association with diabetic nephropathy. We conclude that common polymorphisms in these genes do not strongly influence genetic susceptibility to diabetic nephropathy in white individuals with type 1 diabetes mellitus.

Genetic association analyses of non-synonymous single nucleotide polymorphisms in diabetic nephropathy

AIMS/HYPOTHESIS

Diabetic nephropathy, characterised by persistent proteinuria, hypertension and progressive kidney failure, affects a subset of susceptible individuals with diabetes. It is also a leading cause of end-stage renal disease (ESRD). Non-synonymous (ns) single nucleotide polymorphisms (SNPs) have been reported to contribute to genetic susceptibility in both monogenic disorders and common complex diseases. The objective of this study was to investigate whether nsSNPs are involved in susceptibility to diabetic nephropathy using a case-control design.

METHODS

White type 1 diabetic patients with (cases) and without (controls) nephropathy from eight centres in the UK and Ireland were genotyped for a selected subset of nsSNPs using Illumina's GoldenGate BeadArray assay. A chi (2) test for trend, stratified by centre, was used to assess differences in genotype distribution between cases and controls. Genomic control was used to adjust for possible inflation of test statistics, and the False Discovery Rate method was used to account for multiple testing.

RESULTS

We assessed 1,111 nsSNPs for association with diabetic nephropathy in 1,711 individuals with type 1 diabetes (894 cases, 817 controls). A number of SNPs demonstrated a significant difference in genotype distribution between groups before but not after correction for multiple testing. Furthermore, neither subgroup analysis (diabetic nephropathy with ESRD or diabetic nephropathy without ESRD) nor stratification by duration of diabetes revealed any significant differences between groups.

CONCLUSIONS/INTERPRETATION

The nsSNPs investigated in this study do not appear to contribute significantly to the development of diabetic nephropathy in patients with type 1 diabetes.

Investigation of Adducin 2 (beta) DNA polymorphisms in genetic predisposition to diabetic nephropathy in Type 1 diabetes

AIMS

Adducin 2 (beta) (ADD2) is a biological and positional candidate gene proposed to confer genetic risk for diabetic nephropathy. This study aimed to comprehensively investigate all common and putatively functional polymorphisms in the genomic region encompassing this gene.

METHODS

Tag single nucleotide polymorphisms (n = 23) derived from phase II of the International HapMap Project and in silico functional variants (n = 2) were genotyped in 1467 White individuals from the British Isles (cases, n = 718; control subjects, n = 749) by a combination of Sequenom iPLEX and TaqMan technologies.

RESULTS

Chi(2) analysis of genotype and allele frequencies in cases vs. control subjects revealed weak evidence for association of one variant at the 5% level of significance (rs10164951, P = 0.02). Adjusting for multiple testing in the present case-control collection negated this association.

CONCLUSIONS

We selected an appropriate subset of variants suitable for genetic investigations of the ADD2 gene and report the first investigation of polymorphisms in ADD2 with diabetic nephropathy. Our results suggest that common polymorphisms and putatively functional variants in the ADD2 gene do not strongly influence genetic susceptibility to diabetic nephropathy in this White population with Type 1 diabetes.

Antibody generation through B cell panning on antigen followed by in situ culture and direct RT-PCR on cells harvested en masse from antigen-positive wells

We describe a method for the generation of high-affinity monoclonal antibodies, which combines the power of natural immune responses with in vitro panning, B cell culture, RT-PCR and expression of the recombinant product. B cells from immunised rabbits were incubated at approximately 1000-10,000 cells per well with solid phase antigen coated on the surface of 96-well ELISA plates. Extensive washing removed non-binding cells as well as those B cells, which bound with low affinity. Retained B cells were cultured for 7 days in the presence of activated rabbit splenocyte supernatant and irradiated EL-4-B5 mouse thymoma cells, to induce proliferation and secretion of immunoglobulin. Supernatants were screened to confirm the presence of specific antibody, before the cells were harvested en masse from individual positive wells. Single heavy- and light-chain variable region genes were recovered from individual wells by RT-PCR, critically without the need for isolation of single B cells. Paired VH and VL genes were subsequently expressed as recombinant antibodies and shown to retain the original activity and specificity of the B cell culture supernatants. The method has also been successfully applied to the generation of high-affinity antibodies to antigen expressed on the surface of target cells.

Gene structure and transcript analysis of the human and mouse EGF-TM7 molecule, FIRE

The epidermal growth factor-transmembrane seven (EGF-TM7) family are proteins that express EGF-like domains at their extracellular N-terminus coupled to a classical seven transmembrane (TM7) cassette. Recently, we identified, in mice, a novel member of this family termed FIRE (EMR-4). Here, we present the structure of the mouse and human FIRE genes. The structures of the two genes are strikingly similar, with the positions of the introns, relative to the deduced protein sequences, highly conserved. Moreover, the gene structures are typical of other members of the EGF-TM7 family. Other researchers have identified a point deletion in exon eight of the human FIRE gene, which introduces a frame shift into the cDNA leading to a premature stop codon. Thus, human FIRE is predicted to be expressed only as a soluble protein; even though sequence potentially encoding the TM7 cassette is found in a separate open reading frame of the same mRNA transcript. We explored the possibility that a cell surface expressed form of human FIRE did exist, either as an allelic variant, or as an alternatively spliced transcript. Although, we did identify two alternatively spliced human FIRE transcripts, neither are predicted to express the TM7 cassette. Thus if human FIRE exists, it is likely to be expressed as a soluble secreted molecule.

Modulation of CSF-1-regulated post-natal development with anti-CSF-1 antibody

Colony-stimulating factor-1 (CSF-1) regulates the survival, proliferation and differentiation of macrophages. CSF-1-deficient mice are osteopetrotic due to a lack of osteoclasts, while their tissue macrophage deficiencies and an absence of CSF-1 regulation of CSF-1 receptor-expressing cells in the female reproductive tract contribute to their pleiotropic phenotype. To further understand CSF-1 regulation of macrophages in vivo, we developed a neutralizing anti-mouse CSF-1 antibody which was expressed as a recombinant Fab' fragment and coupled to 40 kDa polyethylene glycol. As developmental regulation by CSF-1 is highest during the early post-natal period, the ability of this anti-CSF-1 reagent to inhibit development was tested by regular subcutaneous injection of mice from post-natal days 0.5-57.5. Antibody treatment decreased growth rate, decreased osteoclast number, induced osteopetrosis, decreased macrophage density in bone marrow, liver, dermis, synovium and kidney and decreased adipocyte size in adipose tissue, thereby inducing phenotypes shared by CSF-1- and CSF-1 receptor-deficient mice. While the antibody blocked macrophage development in some tissues, macrophage densities in other tissues were initially high and were reduced by treatment, proving that the antibody also blocked macrophage maintenance. Since cell surface CSF-1 is sufficient for the maintenance of normal synovial macrophage densities, these studies suggest that anti-CSF-1 Fab'-PEG efficiently neutralizes all three CSF-1 isoforms in vivo, namely the secreted proteoglycan, secreted glycoprotein and cell surface glycoprotein. Since CSF-1 has been shown to enhance chronic disease development in a number of mouse model systems, these studies demonstrate the feasibility of neutralizing CSF-1 effects in these models with an anti-CSF-1 antibody.

Functional analysis of the murine Emr1 promoter identifies a novel purine-rich regulatory motif required for high-level gene expression in macrophages

This study has investigated the transcriptional regulation of the Emr1 gene in murine macrophages and defined an enhancer element within the proximal promoter that is necessary for Emr1 expression in myeloid cells. This element consists of an extended purine-rich sequence (PuRS) of 83 consecutive purine residues containing 9 GGAA sequences, the core binding sequence for members of the Ets family of transcription factors. The Ets factor PU.1 associates with this PuRS element both in vitro and in vivo. Using a standard BLAST search we identified similar PuRS elements in other myeloid and nonmyeloid genes. All PuRS elements tested confer enhancer activity onto a heterologous promoter and chromatin immunoprecipitation experiments revealed that PU.1 associates in vivo with the PuRS elements from the genes expressed in myeloid cells. Our results provide evidence that extended purine-rich sequence elements may constitute a new transcription regulatory motif and that PU.1 association is a prerequisite for macrophage-specific expression.

Cloning of intestinal phospholipase A2 from intestinal epithelial RNA by differential display PCR

Differential display polymerase chain reaction (DD-PCR) is a powerful technique for comparing gene expression between cell types, or between stages of development or differentiation. Differentially expressed genes may be cloned and analysed further. Here we extend the use of DD-PCR to analyse differences in gene expression between two complex epithelia: that of the small intestine and of the large intestine. The aim of this study was to identify genes expressed preferentially in Paneth cells. Paneth cells are secretory epithelial cells putatively involved in host defense and regulation of crypt cell proliferation and are found at the base of the small intestinal crypts adjacent to the stem cell zone. Of 34 clones that were analysed, partial sequencing identified two clones related to known Paneth cell products: a homologue of secretory phospholipase A2 (clone B1) and a homologue of a neutrophil defensin (clone C5). B1 was strongly expressed in Paneth cells, as demonstrated by in-situ hybridization. B1 was also expressed at a lower level in the large intestinal epithelium. A full length B1 cDNA clone was isolated and sequenced, and shown to be highly homologous to type II secretory phospholipase A2 genes, and almost identical to the enhancing factor gene and the putative gene for the MOM-1 locus. B1 expression is limited to the intestinal tract, and we propose that it be designated intestinal phospholipase A2, or i-PLA2. The method we describe is well suited to the rapid identification of genes expressed exclusively or predominantly in Paneth cells.

Inactivation of the F4/80 glycoprotein in the mouse germ line

Macrophages play a crucial role in the defense against pathogens. Distinct macrophage populations can be defined by the expression of restricted cell surface proteins. Resident tissue macrophages, encompassing Kupffer cells of the liver and red pulp macrophages of the spleen, characteristically express the F4/80 molecule, a cell surface glycoprotein related to the seven transmembrane-spanning family of hormone receptors. In this study, gene targeting was used to simultaneously inactivate the F4/80 molecule in the germ line of the mouse and to produce a mouse line that expresses the Cre recombinase under the direct control of the F4/80 promoter (F4/80-Cre knock-in). F4/80-deficient mice are healthy and fertile. Macrophage populations in tissues can develop in the absence of F4/80 expression. Functional analysis revealed that the generation of T-cell-independent B-cell responses and macrophage antimicrobial defense after infection with Listeria monocytogenes are not impaired in the absence of F4/80. Interestingly, tissues of F4/80-deficient mice could not be labeled with anti-BM8, another macrophage subset-specific marker with hitherto undefined molecular antigenic structure. Recombinant expression of a F4/80 cDNA in heterologous cells confirmed this observation, indicating that the targets recognized by the F4/80 and BM8 monoclonal antibodies are identical.

Graduated driver licensing: what works?

BACKGROUND

Graduated driver licensing (GDL) adds an intermediate stage to driver licensing between the learner permit and full licensure stages that is intended to ameliorate the high risk of novice drivers.

OBJECTIVES

To assess the contribution of various elements of GDL to reduction in the crash rates of young novice drivers.

METHODS

An extensive review of the literature was undertaken to synthesise research findings on crash reduction.

RESULTS

Increasing the length of the learner period and the amount practice required has reduced crash risk, partly through improved performance and partly by delaying licensure. Intervening early with traffic violators and making full licensure dependent on a clean driving record provide both general and specific deterrents to unsafe driving. Restrictions on night driving and carrying passengers are effective in reducing the increased risk of these situations. The benefits of multistage instruction and testing as well as the use of visible tags to identify novices have not as yet been adequately evaluated.

CONCLUSIONS

While graduated driver licensing has proven a generally effective means of reducing the crash risk of novice drivers, controlled research is needed to assess the benefits of its individual components.

Organization of the mouse macrophage C-type lectin (Mcl) gene and identification of a subgroup of related lectin molecules

A number of genes encoding C-type lectin molecules have been mapped to the natural killer gene complex (NKC) at the distal region of mouse chromosome 6 and to a syntenic region on human chromosome 12p12-p13. In addition to those receptors which regulate NK cell function, related structures expressed on other cells types have also been localized to this chromosomal region. Among these are a number of recently characterized genes, including macrophage C-type lectin (MCL), macrophage-inducible C-type lectin (Mincle), dendritic cell immunoreceptor (DCIR) and dendritic cell-associated lectin-2 (Dectin-2). The amino acid sequences comprising the single C-type lectin domains of MCL, Mincle, DCIR and Dectin-2 are shown here to be closely related to each other. These molecules show overall similarity to two groups of animal C-type lectins, groups II and V, which demonstrate type II transmembrane topology. In this study, sequence analysis suggests that MCL, Mincle, DCIR and Dectin-2 represent a subset of group II-related C-type lectins which may participate in analogous recognition events on macrophages and dendritic cells. The genomic organization of the MCL gene and the sequence of the promoter region, with putative regulatory elements, were determined from a mouse MCL genomic DNA clone and are described here in detail.

Molecular analysis of the epidermal growth factor-like short consensus repeat domain-mediated protein-protein interactions: dissection of the CD97-CD55 complex

Epidermal growth factor-like (EGF) and short consensus repeat (SCR) domains are commonly found in cell surface and soluble proteins that mediate specific protein-protein recognition events. Unlike the immunoglobulin (Ig) superfamily, very little is known about the general properties of intermolecular interactions encoded by these common modules, and in particular, how specificity of binding is achieved. We have dissected the binding of CD97 (a member of the EGF-TM7 family) to the complement regulator CD55, two cell surface modular proteins that contain EGF and SCR domains, respectively. We demonstrate that the interaction is mediated solely by these domains and is characterized by a low affinity (86 microm) and rapid off-rate (at least 0.6 s(-1)). The interaction is Ca(2+) -dependent but is unaffected by glycosylation of the EGF domains. Using biotinylated multimerized peptides in cell binding assays and surface plasmon resonance, we show that a CD97-related EGF-TM7 molecule (termed EMR2), differing by only three amino acids within the EGF domains, binds CD55 with a K(D) at least an order of magnitude weaker than that of CD97. These results suggest that low affinity cell-cell interactions may be a general feature of highly expressed cell surface proteins and that specificity of SCR-EGF binding can be finely tuned by a small number of amino acid changes on the EGF module surface.

Human epidermal growth factor (EGF) module-containing mucin-like hormone receptor 3 is a new member of the EGF-TM7 family that recognizes a ligand on human macrophages and activated neutrophils

The epidermal growth factor (EGF)-TM7 subgroup of G-protein-coupled receptors is composed predominantly of leukocyte-restricted glycoproteins defined by their unique hybrid structure, in which extracellular EGF-like domains are coupled to a seven-span transmembrane moiety via a mucin-like stalk. The EGF-TM7 group comprises mouse F4/80, human EGF module-containing mucin-like hormone receptor (EMR) 1, human EMR2, and human and mouse CD97, the genes for which map to human chromosome 19p13 and the syntenic regions of the mouse genome. In this study we describe the cloning and characterization of EMR3, a novel human EGF-TM7 molecule, and show the existence of its cellular ligand. The EMR3 gene maps closely to the existing members of the EGF-TM7 family on human chromosome 19p13.1 and, in common with other EGF-TM7 genes, is capable of generating different protein isoforms through alternative splicing. Two alternative splice forms have been isolated: one encoding a 652-amino acid cell surface protein consisting of two EGF-like domains, a mucin stalk, and a putative G-protein-coupled receptor domain and the other encoding a truncated soluble form containing only two EGF-like domains. As with other members of the EGF-TM7 family, EMR3 mRNA displays a predominantly leukocyte-restricted expression pattern, with highest levels in neutrophils, monocytes, and macrophages. Through the use of soluble EMR3 multivalent probes we have shown the presence of a ligand at the surface of monocyte-derived macrophages and activated human neutrophils. These interactions suggest a potential role for EMR3 in myeloid-myeloid interactions during immune and inflammatory responses.

Cloning and characterization of CPVL, a novel serine carboxypeptidase, from human macrophages

Carboxypeptidases are proteases that cleave single amino acids from the carboxy termini of proteins or peptides. In addition to degradative functions in the gut, carboxypeptidases activate or inactivate bioactive peptides such as angiotensin, bradykinin, and endothelin I. Using differential display PCR, we cloned a novel carboxypeptidase expressed in human macrophages but not in other leukocytes. The 476-amino-acid gene product has a putative signal sequence but no transmembrane domain and has striking sequence similarity to serine carboxypeptidases, a large family of enzymes in eukaryotes. Only one serine carboxypeptidase, lysosomal protective protein, has previously been reported in mammals. Among known proteins, this gene is most similar (43% amino acid identity) to vitellogenic carboxypeptidase, a serine carboxypeptidase expressed in mosquito ovaries. Therefore, we have named this new gene carboxypeptidase, vitellogenic-like (CPVL). In addition to monocyte/macrophage-rich sources such as spleen, leukocytes, and placenta, CPVL mRNA is abundantly expressed in heart and kidney, suggesting a separate role for CPVL outside the immune system. The CPVL gene contains at least 13 exons spread over more than 150 kb on human chromosome 7p14-p15. An affinity-purified polyclonal antiserum recognized a protein of approximately 57 kDa in macrophage lysates, but not in lysates from lymphocytes, neutrophils, or monocytes. CPVL protein expression was induced during maturation of monocytes into macrophages. Possible functions for CPVL in macrophages include digestion of phagocytosed particles in the lysosome, participation in an inflammatory protease cascade, and trimming of peptides for antigen presentation.

Exogenous and endogenous corticosteroids modulate blood-brain barrier development in the ovine fetus

We previously reported decreases in blood-brain barrier permeability in the ovine fetus at 80% of gestation after antenatal corticosteroids and shown that permeability is not reduced in newborn lambs after postnatal corticosteroids. We now test the hypotheses that exogenous antenatal corticosteroids decrease blood-brain barrier permeability at 60% but not 90% of gestation in ovine fetuses and that endogenous increases in plasma cortisol concentrations are associated with ontogenic decreases in barrier permeability during gestation. Chronically instrumented ovine fetuses were studied 12 h after the last of four 6-mg dexamethasone or placebo injections were given 12 h apart over 48 h to ewes. Fetuses at 80% of gestation from placebo-treated ewes studied under the same protocol were also included. Blood-brain barrier function was quantified with the blood-to-brain transfer constant (K(i)) to alpha-aminoisobutyric acid. K(i) values were lower in cerebral cortex, caudate nucleus, hippocampus, superior colliculus, thalamus, medulla, and cervical spinal cord in fetuses of dexamethasone- than placebo-treated ewes at 60% but not 90% of gestation. Regional brain K(i) values demonstrated inverse correlations with increases in gestation and plasma cortisol concentrations in most brain regions. We conclude that maternal treatment with exogenous corticosteroids was associated with decreases in blood-brain barrier permeability at 60% but not 90% of gestation and that increases in gestation and endogenous cortisol concentrations were associated with ontogenic decreases in barrier permeability during fetal development.

Human EMR2, a novel EGF-TM7 molecule on chromosome 19p13.1, is closely related to CD97

The epidermal growth factor (EGF)-TM7 proteins [EMR1, (EGF-like molecule containing mucin-like hormone receptor 1) F4/80, and CD97] constitute a recently defined class B GPCR subfamily and are predominantly expressed on leukocytes. These molecules possess N-terminal EGF-like domains coupled to a seven-span transmembrane (7TM) moiety via a mucin-like spacer domain. Genomic mapping analysis has suggested a possible EGF-TM7 gene family on the human chromosome 19p13 region. In this study, a new member of the EGF-TM7 family, EMR2, which shares strikingly similar molecular characteristics with CD97, is described. In addition to mapping closely to CD97 on human chromosome 19p13.1, EMR2 contains a total of five tandem EGF-like domains and expresses similar protein isoforms consisting of various numbers of EGF-like domains as a result of alternative RNA splicing. Furthermore, EMR2 and CD97 exhibit highly homologous EGF-like domains and share identical gene organization, indicating that both genes are the products of a recent gene duplication event. The homologous EGF-like domains enable the identification of both EMR2 and CD97 by monoclonal antibodies (mAbs) raised against the first EGF-like domain of CD97, whereas mAbs directed against the extracellular spacer domain of CD97 are able to differentiate these two proteins. Both EMR2 and CD97 are highly expressed in immune tissues; however, unlike CD97, which is ubiquitously expressed in most cell types, EMR2 expression is restricted to monocytes/M&phi; and granulocytes. EMR2 fails to interact with CD55, the cellular ligand for CD97, suggesting the possibility of a different cellular ligand(s). EMR2 may therefore have a unique function in cells of monocyte/M&phi; and granulocyte lineages.

LNB-TM7, a group of seven-transmembrane proteins related to family-B G-protein-coupled receptors

A number of unusual seven-transmembrane molecules have recently been characterized that have significant amino acid sequence similarity within the membrane-spanning hydrophobic regions and intervening loops to members of G-protein-coupled receptor family B. However, in contrast to the family-B G-protein-coupled receptors, these molecules have unusually large N-terminal extracellular domains that contain a number of well- characterized protein modules. The range of cell types expressing these complex molecules and their potential roles in cell adhesion and signalling have become a major focus of research in a number of biological systems.

Effects of duration of positive-pressure ventilation on blood-brain barrier function in premature lambs

We have been studying the ontogeny of the blood-brain barrier function in ovine fetuses and lambs. During these studies, we have found that the duration of ventilation also influences blood-brain barrier permeability in premature lambs. Chronically instrumented hysterotomy-delivered surfactant-treated premature lambs were studied at 90% or 137 days of gestation (n = 9). Blood-brain barrier function was quantified with the blood-to-brain transfer constant K(i) to alpha-aminoisobutyric acid. Linear regression analysis was used to compare the K(i) values in the brain regions, as the dependent variable, to the duration of ventilation, as the independent variable. There were direct correlations (P < 0.05) between the K(i) values and the duration of ventilation [306 min (mean), 162-474 min (range)] in the cerebral cortex, cerebellum, medulla, caudate nucleus, hippocampus, superior colliculus, inferior colliculus, thalamus, pons, cervical spinal cord, and choroid plexus, but not in the pituitary gland. Ventilatory pressures and rates were established before the onset of the permeability studies. Calculated mean airway pressures [14 cmH(2)O (mean), 7-20 cmH(2)O (range)] from similarly studied premature lambs did not correlate with the duration of positive-pressure ventilation. We conclude that increases in the duration of positive-pressure ventilation predispose premature lambs to increases in regional blood-brain barrier permeability. These alterations in barrier function occur over relatively short time intervals (minutes to hours). In our study, these changes in permeability are most likely not attributable to changes in mean airway pressure.

The behavioral contributors to highway crashes of youthful drivers

The per-mile crash rate of drivers under age 20 is over five times that of the adult population in general, while that of 16-year-old novices is approximately ten times that of adults. Reports of over 2,000 non-fatal crashes involving young drivers were analyzed for behavioral crash contributors as a step in orienting preventive efforts. The great majority of non-fatal crashes resulted from errors in attention, visual search, speed relative to conditions, hazard recognition, and emergency maneuvers, with high speeds and patently risky behavior accounting from but a small minority. The pattern of errors for novices did not differ significantly from that of more experienced youth.

Multivariate analysis of age-related driver ability and performance deficits

A computerized measure of 22 visual, attentional, perceptual, cognitive and psychomotor abilities and a structured road test were administered to 407 elderly drivers age 62 and above. Approximately two-thirds of the sample had been referred to licensing agencies on the basis of observed unsafe incidents and the remainder were volunteers free of reported incidents. Significant correlations (r = 0.4-0.5) were found between unsafe driving incidents and deficiencies in attentional, perceptual, cognitive and psychomotor categories and 0.3 for the visual. A total score based upon all ability measures correctly identified 80% of incident-involved, while misidentifying only 20% of the incident-free drivers. Unsafe driving incidents evidenced significant but small positive correlations (r = 0.1-0.2) with road test errors indicative of skill deficiencies but not with errors in routine safe driving practices. Substantial examiner differences attenuated relationships involving road performances, and correlations with skill-related performances rose (r = 0.2-0.3) when these effects were partialled out. Intercorrelations among measured abilities were high, indicating the need for caution in interpreting reported relationships between individual abilities and unsafe driving incidents. The authors also caution against interpreting correlations found in highly selected samples as representing the magnitude of relationships in the population at large.

Development of a standardized boating sobriety test

A sobriety test capable of being administered on boats was developed as an aid in establishing probable cause to request a breath sample of recreational boat operators suspected of being over the legal alcohol limit. In a laboratory phase some 12 candidate measures suitable for use in a boating environment were assessed for their relationship to blood alcohol levels through administration to 32 subjects tested at blood alcohol concentrations (BACs) of 0.00, 0.06 and 0.12%. Four measures showing significant relationships to BAC were then administered by marine police to a sample of 60 recreational boaters found to have BACs ranging from 0.0 to 0.20%. Three measures still showing significant relationships to alcohol were horizontal gaze Nystagmus given in a seated position, reciting the alphabet from A to Z, and clapping hands alternately with palm and back of hand, while counting. Correlation of the measures with BAC, and the ability to distinguish boaters over and under a 0.10% limit were similar to those found over the same BAC range with the standardized field sobriety test (SFST) for motor vehicle operators. Where there is not sufficient cause to request a boat operator to proceed to shore for testing, a standardized boating sobriety test (SBST) making use of the three measures appears to be a suitable replacement for the SFST.

The effect of lane line width and contrast upon lanekeeping

The combined effect of lane line width and line-pavement contrast upon lanekeeping was studied through simulation. Some 124 subjects, ages 17-79 (x = 56.30), 52% male, each performed 42 trials over road segments representing three levels of width crossed with 14 line-pavement contrast ratios. Lanekeeping performance was recorded in terms of heading error, position error, lane excursions and road excursions. Subjects were stratified into two levels of ability on a combined measure of visual, attentional and psychomotor variables known to decline with age. Contrast and width had a negligible effect upon performance except at very low contrast ratios, ca 1.02 at high pavement luminance levels (e.g. concrete) and 1.04 for very low luminance levels (e.g. asphalt). These ratios are similar to those encountered at night on wet roads. Mean overall performance error at the low contrast ratios increased by a factor of 1.6, 1.8 and 2.2 for 8, 6 and 4" widths, respectively. Lower ability subjects exhibited greater error at almost all contrast ratios, with no consistent relationship between degree of decrement and either width or contrast. The results suggest that lane line width and contrast have a negligible effect upon lanekeeping performance except at extremely low levels of contrast, where both have large effects. Further research in the roadway environment is needed to determine the relationships of line width and contrast ratio to lanekeeping on normal and degraded surface conditions.

Cloning of a novel C-type lectin expressed by murine macrophages

We report the cloning of a novel macrophage-restricted C-type lectin by differential display polymerase chain reaction. This molecule, named mouse macrophage C-type lectin, is a 219-amino acid, type II transmembrane protein with a single extracellular C-type lectin domain. Northern blot analysis indicates that it is expressed in cell lines and normal mouse tissues in a macrophage-restricted manner. The cDNA and genomic sequences of mouse macrophage C-type lectin indicate that it is related to the Group II animal C-type lectins. The mcl gene locus has been mapped between the genes for the interleukin-17 receptor and CD4 on mouse chromosome 6, the same chromosome as the mouse natural killer cell gene complex.

The EGF-TM7 family: unusual structures at the leukocyte surface

The isolation of cDNA clones encoding mouse F4/80, human epidermal growth factor (EGF) module-containing mucin-like hormone receptor 1 (EMR1) and human CD97 has resulted in the description of a novel family of seven-transmembrane spanning cell surface molecules. These members of the EGF-TM7 family are characterized by a variable number of NH2-terminal EGF domains and seven transmembrane-spanning hydrophobic regions, which demonstrate a degree of sequence homology to the corresponding region in members of the G-protein-coupled peptide hormone receptor family. The F4/80 molecule is macrophage-restricted, as determined by immunohistochemical analysis of a wide range mouse tissues, while mRNA transcripts encoding EMR1, the predicted human F4/80 homologue, also appear to be abundantly expressed by cells of the myelomonocytic lineage. CD97, for which a cellular ligand has been identified (CD55), is expressed on a diverse array of leukocytes and is markedly upregulated on activated T and B cells. The regulation of expression of the EGF-TM7 genes, the physiologic function(s) of these novel receptors and the further identification of their ligands is the subject of both intense study and this review.

Estimating blood alcohol level from observable signs

Attempts to induce hosts and friends to prevent drinkers from reaching dangerous levels of alcohol impairment depend upon the ability to judge impairment from observable signs of physical appearance and behavior. In a study of this ability, researchers first observed and recorded signs of change in behavior and physical appearance among dosed drinkers in small social groups (n = 149). Signs were grouped into impairment levels corresponding to three broad categories of blood alcohol concentration (BAC): < 0.04% (no signs), 0.04%-0.08%, and > 0.08%. Next, drinkers were then classified into judged impairment level by guests observing small numbers in social groups (n = 333), hosts observing large numbers in social groups (n = 480), and servers observing patrons in public establishments (n = 436). A random half of the observers in each setting were given instructional guidance in the relationships of signs to impairment level. Results showed all observers to exceed chance in their classifications of drinker impairment, with observations in the small social groups being significantly more accurate than those in the other two groups. A beneficial instructional guidance effect was significant for the social groups, with the greatest benefit found in detecting those over 0.04% in the small groups. The authors conclude that, while people are fairly accurate in judging alcohol impairment, their accuracy is greatest and guidance most effective in detecting the presence rather than degree of impairment and when attention can be concentrated upon a few drinkers at a time.

Accident prevention versus recidivism prevention courses for repeat traffic offenders

Most U.S. jurisdictions include some form of educational program among the driver improvement actions for repeated traffic offenders. The majority of programs fall into two categories: accident prevention programs seeking primarily to foster safe driving practices, and recidivism prevention programs seeking primarily to foster lawful driving behavior. Over 16,000 multiple traffic offenders were divided between courses representing each type of program. Those taking part in the recidivism prevention course evidence significantly fewer accidents and violations during the following year than did their counterparts participating in the accident prevention course. Offenders failing to participate in either course, and therefore having their licenses suspended, showed significantly fewer accidents and violations than did participants in either course. The results suggest that instruction designed primarily to reduce recidivism is more effective in reducing both violations and accidents of repeat offenders than instruction that is solely directed toward accident prevention.