Mutation in KERA Identified by Linkage Analysis and Targeted Resequencing in a Pedigree with Premature Atherosclerosis

Aims

Genetic factors explain a proportion of the inter-individual variation in the risk for atherosclerotic events, but the genetic basis of atherosclerosis and atherothrombosis in families with Mendelian forms of premature atherosclerosis is incompletely understood. We set out to unravel the molecular pathology in a large kindred with an autosomal dominant inherited form of premature atherosclerosis.

Methods and Results

Parametric linkage analysis was performed in a pedigree comprising 4 generations, of which a total of 11 members suffered from premature vascular events. A parametric LOD-score of 3.31 was observed for a 4.4 Mb interval on chromosome 12. Upon sequencing, a non-synonymous variant in KERA (c.920C>G; p.Ser307Cys) was identified. The variant was absent from nearly 28,000 individuals, including 2,571 patients with premature atherosclerosis. KERA, a proteoglycan protein, was expressed in lipid-rich areas of human atherosclerotic lesions, but not in healthy arterial specimens. Moreover, KERA expression in plaques was significantly associated with plaque size in a carotid-collar Apoe^−/− mice (r² = 0.69; p<0.0001).

Conclusion

A rare variant in KERA was identified in a large kindred with premature atherosclerosis. The identification of KERA in atherosclerotic plaque specimen in humans and mice lends support to its potential role in atherosclerosis.     

Asthma and Chronic Obstructive Pulmonary Disease (COPD) Prevalence and Health Services Use in Ontario Métis: A Population-Based Cohort Study

Introduction

Chronic respiratory diseases cause a significant health and economic burden around the world. In Canada, Aboriginal populations are at increased risk of asthma and chronic obstructive pulmonary disease (COPD). There is little known, however, about these diseases in the Canadian Métis population, who have mixed Aboriginal and European ancestry. A population-based study was conducted to quantify asthma and COPD prevalence and health services use in the Métis population of Ontario, Canada’s largest province.

Methods

The Métis Nation of Ontario Citizenship Registry was linked to provincial health administrative databases to measure and compare burden of asthma and COPD between the Métis and non-Métis populations of Ontario between 2009 and 2012. Asthma and COPD prevalence, health services use (general physician and specialist visits, emergency department visits, hospitalizations), and mortality were measured.

Results

Prevalences of asthma and COPD were 30% and 70% higher, respectively, in the Métis compared to the general Ontario population (p<0.001). General physician and specialist visits were significantly lower in Métis with asthma, while general physician visits for COPD were significantly higher. Emergency department visits and hospitalizations were generally higher for Métis compared to non-Métis with either disease. All-cause mortality in Métis with COPD was 1.3 times higher compared to non-Métis with COPD (p = 0.01).

Conclusion

There is a high burden of asthma and COPD in Ontario Métis, with significant prevalence and acute health services use related to these diseases. Lower rates of physician visits suggest barriers in access to primary care services.     

How formalin affects the outcome of routine and special stains

The discovery of formaldehyde for preserving tissue structures produced a new dimension in microscopy. Preserving structure and morphology became important; therefore, identifying a proper fixing agent for particular structures, chemical entities, and tissues, also became important. The methods for demonstrating tissue structures evolved and were implemented with careful observation and documentation of the results and outcomes. Formalin was incorporated into many techniques, and provided helpful results in many cases and hindrances in others. The effects of formalin on the outcomes of routine and special staining techniques are reported here.     

Enhanced biofilm and extracellular matrix production by chronic carriage versus acute isolates of Salmonella Typhi

Salmonella Typhi is the primary causative agent of typhoid fever; an acute systemic infection that leads to chronic carriage in 3–5% of individuals. Chronic carriers are asymptomatic, difficult to treat and serve as reservoirs for typhoid outbreaks. Understanding the factors that contribute to chronic carriage is key to development of novel therapies to effectively resolve typhoid fever. Herein, although we observed no distinct clustering of chronic carriage isolates via phylogenetic analysis, we demonstrated that chronic isolates were phenotypically distinct from acute infection isolates. Chronic carriage isolates formed significantly thicker biofilms with greater biomass that correlated with significantly higher relative levels of extracellular DNA (eDNA) and DNABII proteins than biofilms formed by acute infection isolates. Importantly, extracellular DNABII proteins include integration host factor (IHF) and histone-like protein (HU) that are critical to the structural integrity of bacterial biofilms. In this study, we demonstrated that the biofilm formed by a chronic carriage isolate in vitro, was susceptible to disruption by a specific antibody against DNABII proteins, a successful first step in the development of a therapeutic to resolve chronic carriage.     

Serum soluble HLA-E in melanoma: a new potential immune-related marker in cancer

Background

Tumor-derived soluble factors, including soluble HLA molecules, can contribute to cancer immune escape and therefore impact on clinical course of malignant diseases. We previously reported that melanoma cells produce, in vitro, soluble forms of the non-classical MHC class I molecule HLA-E (sHLA-E). In order to investigate sHLA-E production by various tumors and to address its potential value as a tumor-associated marker, we developed a specific ELISA for the quantification of sHLA-E in biological fluids.

Methodology/Principal Findings

We developed a sHLA-E specific and sensitive ELISA and we showed that serum sHLA-E levels were significantly elevated (P<0.01) in melanoma patients (n = 127), compared with healthy donors (n = 94). sHLA-E was also detected in the culture supernatants of a wide variety of tumor cell lines (n = 98) including melanomas, kidney, colorectal and breast cancers. Cytokines regulation of sHLA-E production by tumor cells was also carried out. IFN-γ, IFN-α and TNF-α were found to upregulate sHLA-E production by tumor cells.

Conclusions/Significance

In view of the broad tumor tissue release of HLA-E and its up-regulation by inflammatory cytokines, sHLA-E should be studied for its involvement in immune responses against tumors. Interestingly, our results demonstrated a positive association between the presence of serum sHLA-E and melanoma. Therefore, the determination of sHLA-E levels, using ELISA approach, may be investigated as a clinical marker in cancer patients.     

Functional interactions of voltage sensor charges with an S2 hydrophobic plug in hERG channels

Human ether-à-go-go–related gene (hERG, Kv11.1) potassium channels have unusually slow activation and deactivation kinetics. It has been suggested that, in fast-activating Shaker channels, a highly conserved Phe residue (F290) in the S2 segment forms a putative gating charge transfer center that interacts with S4 gating charges, i.e., R362 (R1) and K374 (K5), and catalyzes their movement across the focused electric field. F290 is conserved in hERG (F463), but the relevant residues in the hERG S4 are reversed, i.e., K525 (K1) and R537 (R5), and there is an extra positive charge adjacent to R537 (i.e., K538). We have examined whether hERG channels possess a transfer center similar to that described in Shaker and if these S4 charge differences contribute to slow gating in hERG channels. Of five hERG F463 hydrophobic substitutions tested, F463W and F463Y shifted the conductance–voltage (G-V) relationship to more depolarized potentials and dramatically slowed channel activation. With the S4 residue reversals (i.e., K525, R537) taken into account, the closed state stabilization by F463W is consistent with a role for F463 that is similar to that described for F290 in Shaker. As predicted from results with Shaker, the hERG K525R mutation destabilized the closed state. However, hERG R537K did not stabilize the open state as predicted. Instead, we found the neighboring K538 residue to be critical for open state stabilization, as K538R dramatically slowed and right-shifted the voltage dependence of activation. Finally, double mutant cycle analysis on the G-V curves of F463W/K525R and F463W/K538R double mutations suggests that F463 forms functional interactions with K525 and K538 in the S4 segment. Collectively, these data suggest a role for F463 in mediating closed–open equilibria, similar to that proposed for F290 in Shaker channels.     

Landing Surface Color Preferences of Spathius agrili (Hymenoptera: Braconidae), a Parasitoid of Emerald Ash Borer, Agrilus planipennis (Coleoptera: Buprestidae)

The color preferences for landing surfaces were examined for Spathius agrili (Hymenoptera: Braconidae), a parasitic wasp introduced for biocontrol of emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae). Lures with the 3-component pheromone blend of male S. agrili were used to activate upwind flight by virgin female S. agrili in a laminar flow wind tunnel. Paper discs with halves of two different colors (combination pairs of black, white, red, yellow, green, or purple), with the pheromone lure in the center, were tested to quantify preferences for landing on one color over another. Females landed preferentially on green, yellow, and white surfaces, and landed the least frequently on red, black, and purple surfaces. Changes in color preferences due to adjacent colors were observed and discussed.