Disrupted intercellular bridges and spermatogenesis in fatty acyl-CoA reductase 1 knockout mice: A new model of ether lipid deficiency.

Peroxisomal fatty acyl-CoA reductase 1 (FAR1) is a rate-limiting enzyme for ether lipid (EL) synthesis. Gene mutations in FAR1 cause a rare human disease. Furthermore, altered EL homeostasis has also been associated with various prevalent human diseases. Despite their importance in human health, the exact cellular functions of FAR1 and EL are not well-understood. Here, we report the generation and initial characterization of the first Far1 knockout (KO) mouse model. Far1 KO mice were subviable and displayed growth retardation. The adult KO male mice had smaller testes and were infertile. H&E and immunofluorescent staining showed fewer germ cells in seminiferous tubules. Round spermatids were present but no elongated spermatids or spermatozoa were observed, suggesting a spermatogenesis arrest at this stage. Large multi-nucleated giant cells (MGC) were found lining the lumen of seminiferous tubules with many of them undergoing apoptosis. The immunofluorescent signal of TEX14, an essential component of intercellular bridges (ICB) between developing germ cells, was greatly reduced and mislocalized in KO testis, suggesting the disrupted ICBs as an underlying cause of MGC formation. Integrative analysis of our total testis RNA-sequencing results and published single-cell RNA-sequencing data unveiled cell type-specific molecular alterations underlying the spermatogenesis arrest. Many genes essential for late germ cell development showed dramatic downregulation, whereas genes essential for extracellular matrix dynamics and cell-cell interactions were among the most upregulated genes. Together, this work identified the cell type-specific requirement of ELs in spermatogenesis and suggested a critical role of Far1/ELs in the formation/maintenance of ICB during meiosis.

Genome-wide Association Study Identifies HLA-DPB1 as a Significant Risk Factor for Severe Aplastic Anemia.

Severe aplastic anemia (SAA) is a rare disorder characterized by hypoplastic bone marrow and progressive pancytopenia. The etiology of acquired SAA is not understood but is likely related to abnormal immune responses and environmental exposures. We conducted a genome-wide association study of individuals with SAA genetically matched to healthy controls in discovery (359 cases, 1,396 controls) and validation sets (175 cases, 1,059 controls). Combined analyses identified linked SNPs in distinct blocks within the major histocompatibility complex on 6p21. The top SNP encodes p.Met76Val in the P4 binding pocket of the HLA class II gene HLA-DPB1 (rs1042151A>G, odds ratio [OR] 1.75, 95% confidence interval [CI] 1.50-2.03, p = 1.94 × 10-13) and was associated with HLA-DP cell surface expression in healthy individuals (p = 2.04 × 10-6). Phylogenetic analyses indicate that Val76 is not monophyletic and likely occurs in conjunction with different HLA-DP binding groove conformations. Imputation of HLA-DPB1 alleles revealed increased risk of SAA associated with Val76-encoding alleles DPB1∗03:01, (OR 1.66, p = 1.52 × 10-7), DPB1∗10:01 (OR 2.12, p = 0.0003), and DPB1∗01:01 (OR 1.60, p = 0.0008). A second SNP near HLA-B, rs28367832G>A, reached genome-wide significance (OR 1.49, 95% CI 1.22-1.78, p = 7.27 × 10-9) in combined analyses; the association remained significant after excluding cases with clonal copy-neutral loss-of-heterozygosity affecting class I HLA genes (8.6% of cases and 0% of controls). SNPs in the HLA class II gene HLA-DPB1 and possibly class I (HLA-B) are associated with SAA. The replacement of Met76 to Val76 in certain HLA-DPB1 alleles might influence risk of SAA through mechanisms involving DP peptide binding specificity, expression, and/or other factors affecting DP function.

Inferred expression regulator activities suggest genes mediating cardiometabolic genetic signals.

Expression QTL (eQTL) analyses have suggested many genes mediating genome-wide association study (GWAS) signals but most GWAS signals still lack compelling explanatory genes. We have leveraged an adipose-specific gene regulatory network to infer expression regulator activities and phenotypic master regulators (MRs), which were used to detect activity QTLs (aQTLs) at cardiometabolic trait GWAS loci. Regulator activities were inferred with the VIPER algorithm that integrates enrichment of expected expression changes among a regulator's target genes with confidence in their regulator-target network interactions and target overlap between different regulators (i.e., pleiotropy). Phenotypic MRs were identified as those regulators whose activities were most important in predicting their respective phenotypes using random forest modeling. While eQTLs were typically more significant than aQTLs in cis, the opposite was true among candidate MRs in trans. Several GWAS loci colocalized with MR trans-eQTLs/aQTLs in the absence of colocalized cis-QTLs. Intriguingly, at the 1p36.1 BMI GWAS locus the EPHB2 cis-aQTL was stronger than its cis-eQTL and colocalized with the GWAS signal and 35 BMI MR trans-aQTLs, suggesting the GWAS signal may be mediated by effects on EPHB2 activity and its downstream effects on a network of BMI MRs. These MR and aQTL analyses represent systems genetic methods that may be broadly applied to supplement standard eQTL analyses for suggesting molecular effects mediating GWAS signals.

Germline variants in hereditary breast cancer genes are associated with early age at diagnosis and family history in Guatemalan breast cancer.

PURPOSE: Mutations in hereditary breast cancer genes play an important role in the risk for cancer. METHODS: Cancer susceptibility genes were sequenced in 664 unselected breast cancer cases from Guatemala. Variants were annotated with ClinVar and VarSome. RESULTS: A total of 73 out of 664 subjects (11%) had a pathogenic variant in a high or moderate penetrance gene. The most frequently mutated genes were BRCA1 (37/664, 5.6%) followed by BRCA2 (15/664, 2.3%), PALB2 (5/664, 0.8%), and TP53 (5/664, 0.8%). Pathogenic variants were also detected in the moderate penetrance genes ATM, BARD1, CHEK2, and MSH6. The high ratio of BRCA1/BRCA2 mutations is due to two potential founder mutations: BRCA1 c.212 + 1G > A splice mutation (15 cases) and BRCA1 c.799delT (9 cases). Cases with pathogenic mutations had a significantly earlier age at diagnosis (45 vs 51 years, P < 0.001), are more likely to have had diagnosis before menopause, and a higher percentage had a relative with any cancer (51% vs 37%, P = 0.038) or breast cancer (33% vs 15%, P < 0.001). CONCLUSIONS: Hereditary breast cancer mutations were observed among Guatemalan women, and these women are more likely to have early age at diagnosis and family history of cancer. These data suggest the use of genetic testing in breast cancer patients and those at high risk as part of a strategy to reduce breast cancer mortality in Guatemala.

Reduced preload increases Mechanical Control (strain-rate dependence) of Relaxation by modifying myosin kinetics.

Rapid myocardial relaxation is essential in maintaining cardiac output, and impaired relaxation is an early indicator of diastolic dysfunction. While the biochemical modifiers of relaxation are well known to include calcium handling, thin filament activation, and myosin kinetics, biophysical and biomechanical modifiers can also alter relaxation. We have previously shown that the relaxation rate is increased by an increasing strain rate, not a reduction in afterload. The slope of the relaxation rate to strain rate relationship defines Mechanical Control of Relaxation (MCR). To investigate MCR further, we performed in vitro experiments and computational modeling of preload-adjustment using intact rat cardiac trabeculae. Trabeculae studies are often performed using isometric (fixed-end) muscles at optimal length (Lo, length producing maximal developed force). We determined that reducing muscle length from Lo increased MCR by 20%, meaning that reducing preload could substantially increase the sensitivity of the relaxation rate to the strain rate. We subsequently used computational modeling to predict mechanisms that might underlie this preload-dependence. Computational modeling was not able to fully replicate experimental data, but suggested that thin-filament properties are not sufficient to explain preload-dependence of MCR because the model required the thin-filament to become more activated at reduced preloads. The models suggested that myosin kinetics may underlie the increase in MCR at reduced preload, an effect that can be enhanced by force-dependence. Relaxation can be modified and enhanced by reduced preload. Computational modeling implicates myosin-based targets for treatment of diastolic dysfunction, but further model refinements are needed to fully replicate experimental data.

Muscle metaboreflex-induced increases in effective arterial elastance: effect of heart failure.

Dynamic exercise elicits robust increases in sympathetic activity in part due to muscle metaboreflex activation (MMA), a pressor response triggered by activation of skeletal muscle afferents. MMA during dynamic exercise increases arterial pressure by increasing cardiac output via increases in heart rate, ventricular contractility, and central blood volume mobilization. In heart failure, ventricular function is compromised, and MMA elicits peripheral vasoconstriction. Ventricular-vascular coupling reflects the efficiency of energy transfer from the left ventricle to the systemic circulation and is calculated as the ratio of effective arterial elastance (Ea) to left ventricular maximal elastance (Emax). The effect of MMA on Ea in normal subjects is unknown. Furthermore, whether muscle metaboreflex control of Ea is altered in heart failure has not been investigated. We utilized two previously published methods of evaluating Ea [end-systolic pressure/stroke volume (EaPV)] and [heart rate × vascular resistance (EaZ)] during rest, mild treadmill exercise, and MMA (induced via partial reductions in hindlimb blood flow imposed during exercise) in chronically instrumented conscious canines before and after induction of heart failure via rapid ventricular pacing. In healthy animals, MMA elicits significant increases in effective arterial elastance and stroke work that likely maintains ventricular-vascular coupling. In heart failure, Ea is high, and MMA-induced increases are exaggerated, which further exacerbates the already uncoupled ventricular-vascular relationship, which likely contributes to the impaired ability to raise stroke work and cardiac output during exercise in heart failure.

Computed Tomography Findings in Vernix Caseosa Peritonitis.

INTRODUCTION: Vernix caseosa peritonitis (VCP) is a rare peripartum complication secondary to the introduction of fetal vernix into the maternal peritoneal cavity. Vernix caseosa peritonitis typically manifests a few hours to days after a cesarian section and is often initially misdiagnosed as a more common disease process resulting in delayed diagnosis. We report the computed tomography (CT) findings in 2 patients with VCP and reviewed the previously reported CT findings of VCP. CASES: Two patients, aged 17 and 24 years, presented with signs and symptoms of peritonitis within days of undergoing a cesarian section. In both cases, CT scans of the abdomen and pelvis demonstrated ascites and multiple small, well-defined, peripherally enhancing, cystic peritoneal nodules which were most prominent around the liver and became larger and more numerous over time. Antibiotic therapy was not effective, subsequent laparoscopic peritoneal biopsy demonstrated VCP, and patients were successfully treated with lavage and the addition of intravenous steroids. CONCLUSIONS: Vernix caseosa peritonitis is an underrecognized disorder that is most often mistaken for other more common causes of peritonitis. In the setting of peripartum peritonitis, the CT findings of ascites with multiple small, well-defined, peripherally enhancing, cystic peritoneal nodules, especially adjacent to the liver, which grow in size and number strongly suggests VCP.

HIV-1 subtype variability and transmitted drug resistance in a culturally diverse population in Western Sydney, New South Wales, Australia.

Background Transmitted human immunodeficiency virus type 1 (HIV-1) drug resistance (TDR) is an important contributor to antiretroviral treatment failure, and is associated with HIV-1 transmission among men who have sex with men (MSM), non-MSM clusters and individuals diagnosed with concurrent sexually transmissible infections (STI). Western Sydney has a culturally diverse population, with a high proportion of non-Australian-born individuals. This study describes the prevalence of TDR and non-B HIV-1 subtypes in a clinic-based population. METHODS: A clinic database was examined for all newly diagnosed treatment-naïve HIV-1 patients and information on their HIV-1 resistance and subtype, demographics including country of birth and diagnosis of a bacterial sexually transmissible infection was collected. RESULTS: Data were available from 74/79 individuals (62 cis-male, 16 cis-female and 1 transgender woman). Of the 74 genotypes, the prevalence of non-B subtypes and TDR was 43/74 (58%; 95%CI = 46.9-69.3) and 14/74 (19%; 95%CI = 10.0 to 27.8). It was also found that 30/79 (38%) had a concurrent bacterial STI. TDR was associated with subtype B infection (OR 3.53; 95%CI = 1.41-8.82; P = 0.007) and being born in Australia (OR 12.0; 95%CI = 2.45-58.86; P = 0.002). CONCLUSION: The relative prevalence of non-B HIV-1 subtypes and TDR is higher in Western Sydney than in the rest of Australia. TDR is associated with subtype B HIV-1 and being Australian born, suggesting ongoing local transmission. This highlights the diversity of the HIV epidemic locally and the need for interventions to prevent ongoing HIV transmission.

How myofilament strain and strain rate lead the dance of the cardiac cycle.

Movement of the myocardium can modify organ-level cardiac function and its molecular (crossbridge) mechanisms. This motion, which is defined by myocardial strain and strain rate (muscle shortening, lengthening, and the speed of these movements), occurs throughout the cardiac cycle, including during isovolumic periods. This review highlights how the left ventricular myocardium moves throughout the cardiac cycle, how muscle mechanics experiments provide insight into the regulation of forces used to move blood in and out of the left ventricle, and its impact on (and regulation by) crossbridge and sarcomere kinetics. We specifically highlight how muscle mechanics experiments explain how myocardial relaxation is accelerated by lengthening (strain rate) during late systole and isovolumic relaxation, a lengthening which has been measured in human hearts. Advancing and refining both in vivo measurement and ex vivo protocols with physiologic strain and strain rates could reveal important insights into molecular (crossbridge) kinetics. These advances could provide an improvement in both diagnosis and precise treatment of cardiac dysfunction.

Specialized landing maneuvers in Spix's disk-winged bats (Thyroptera tricolor) reveal linkage between roosting ecology and landing biomechanics.

Disk-winged bats (Thyroptera spp.) are the only mammals that use suction to cling to smooth surfaces, having evolved suction cups at the bases of the thumbs and feet that facilitate attachment to specialized roosts: the protective funnels of ephemeral furled leaves. We predicted that this combination of specialized morphology and roosting ecology is coupled with concomitantly specialized landing maneuvers. We tested this by investigating landings in Thyroptera tricolor using high-speed videography and a force-measuring landing pad disguised within a furled leaf analogue. We found that their landing maneuvers are distinct among all bats observed to date. Landings comprised three phases: (1) approach, (2) ballistic descent and (3) adhesion. During approach, bats adjusted trajectory until centered in front of and above the landing site, typically the leaf's protruding apex. Bats initiated ballistic descent by arresting the wingbeat cycle and tucking their wings to descend toward the leaf, simultaneously extending the thumb disks cranially. Adhesion commenced when the thumb disks contacted the landing site. Significant body reorientation occurred only during adhesion, and only after contact, when the thumb disks acted as fulcra about which the bats pitched 75.02±26.17 deg (mean±s.d.) to swing the foot disks into contact. Landings imposed 6.98±1.89 bodyweights of peak impact force. These landing mechanics are likely to be influenced by the orientation, spatial constraints and compliance of furled leaf roosts. Roosting ecology influences critical aspects of bat biology, and taken as a case study, this work suggests that roosting habits and landing mechanics could be functionally linked across bats.

Differential Effects of Isoproterenol on Regional Myocardial Mechanics in Rat Using Three-Dimensional Cine DENSE Cardiovascular Magnetic Resonance.

The present study assessed the acute effects of isoproterenol on left ventricular (LV) mechanics in healthy rats with the hypothesis that ß-adrenergic stimulation influences the mechanics of different myocardial regions of the LV wall in different ways. To accomplish this, magnetic resonance images were obtained in the LV of healthy rats with or without isoproterenol infusion. The LV contours were divided into basal, midventricular, and apical regions. Additionally, the midventricular myocardium was divided into three transmural layers with each layer partitioned into four segments (i.e., septal, inferior, lateral, and anterior). Peak systolic strains and torsion were quantified for each region. Isoproterenol significantly increased peak systolic radial strain and circumferential-longitudinal (CL) shear strain, as well as ventricular torsion, throughout the basal, midventricle, and apical regions. In the midventricle, isoproterenol significantly increased peak systolic radial strain, and induced significant increases in peak systolic circumferential strain and longitudinal strain in the septum. Isoproterenol consistently increased peak systolic CL shear strain in all midventricular segments. Ventricular torsion was significantly increased in nearly all segments except the inferior subendocardium. The effects of isoproterenol on LV systolic mechanics (i.e., three-dimensional (3D) strains and torsion) in healthy rats depend on the region. This region dependency is also strain component-specific. These results provide insight into the regional response of LV mechanics to ß-adrenergic stimulation in rats and could act as a baseline for future studies on subclinical abnormalities associated with the inotropic response in heart disease.

Characterising cis-regulatory variation in the transcriptome of histologically normal and tumour-derived pancreatic tissues.

OBJECTIVE: To elucidate the genetic architecture of gene expression in pancreatic tissues. DESIGN: We performed expression quantitative trait locus (eQTL) analysis in histologically normal pancreatic tissue samples (n=95) using RNA sequencing and the corresponding 1000 genomes imputed germline genotypes. Data from pancreatic tumour-derived tissue samples (n=115) from The Cancer Genome Atlas were included for comparison. RESULTS: We identified 38 615 cis-eQTLs (in 484 genes) in histologically normal tissues and 39 713 cis-eQTL (in 237 genes) in tumour-derived tissues (false discovery rate <0.1), with the strongest effects seen near transcriptional start sites. Approximately 23% and 42% of genes with significant cis-eQTLs appeared to be specific for tumour-derived and normal-derived tissues, respectively. Significant enrichment of cis-eQTL variants was noted in non-coding regulatory regions, in particular for pancreatic tissues (1.53-fold to 3.12-fold, p≤0.0001), indicating tissue-specific functional relevance. A common pancreatic cancer risk locus on 9q34.2 (rs687289) was associated with ABO expression in histologically normal (p=5.8×10-8) and tumour-derived (p=8.3×10-5) tissues. The high linkage disequilibrium between this variant and the O blood group generating deletion variant in ABO (exon 6) suggested that nonsense-mediated decay (NMD) of the 'O' mRNA might explain this finding. However, knockdown of crucial NMD regulators did not influence decay of the ABO 'O' mRNA, indicating that a gene regulatory element influenced by pancreatic cancer risk alleles may underlie the eQTL. CONCLUSIONS: We have identified cis-eQTLs representing potential functional regulatory variants in the pancreas and generated a rich data set for further studies on gene expression and its regulation in pancreatic tissues.

Identification of a novel susceptibility locus at 13q34 and refinement of the 20p12.2 region as a multi-signal locus associated with bladder cancer risk in individuals of European ancestry.

Candidate gene and genome-wide association studies (GWAS) have identified 15 independent genomic regions associated with bladder cancer risk. In search for additional susceptibility variants, we followed up on four promising single-nucleotide polymorphisms (SNPs) that had not achieved genome-wide significance in 6911 cases and 11 814 controls (rs6104690, rs4510656, rs5003154 and rs4907479, P < 1 × 10(-6)), using additional data from existing GWAS datasets and targeted genotyping for studies that did not have GWAS data. In a combined analysis, which included data on up to 15 058 cases and 286 270 controls, two SNPs achieved genome-wide statistical significance: rs6104690 in a gene desert at 20p12.2 (P = 2.19 × 10(-11)) and rs4907479 within the MCF2L gene at 13q34 (P = 3.3 × 10(-10)). Imputation and fine-mapping analyses were performed in these two regions for a subset of 5551 bladder cancer cases and 10 242 controls. Analyses at the 13q34 region suggest a single signal marked by rs4907479. In contrast, we detected two signals in the 20p12.2 region-the first signal is marked by rs6104690, and the second signal is marked by two moderately correlated SNPs (r(2) = 0.53), rs6108803 and the previously reported rs62185668. The second 20p12.2 signal is more strongly associated with the risk of muscle-invasive (T2-T4 stage) compared with non-muscle-invasive (Ta, T1 stage) bladder cancer (case-case P ≤ 0.02 for both rs62185668 and rs6108803). Functional analyses are needed to explore the biological mechanisms underlying these novel genetic associations with risk for bladder cancer.

Meta-analysis of genome-wide association studies identifies multiple lung cancer susceptibility loci in never-smoking Asian women.

Genome-wide association studies (GWAS) of lung cancer in Asian never-smoking women have previously identified six susceptibility loci associated with lung cancer risk. To further discover new susceptibility loci, we imputed data from four GWAS of Asian non-smoking female lung cancer (6877 cases and 6277 controls) using the 1000 Genomes Project (Phase 1 Release 3) data as the reference and genotyped additional samples (5878 cases and 7046 controls) for possible replication. In our meta-analysis, three new loci achieved genome-wide significance, marked by single nucleotide polymorphism (SNP) rs7741164 at 6p21.1 (per-allele odds ratio (OR) = 1.17; P = 5.8 × 10(-13)), rs72658409 at 9p21.3 (per-allele OR = 0.77; P = 1.41 × 10(-10)) and rs11610143 at 12q13.13 (per-allele OR = 0.89; P = 4.96 × 10(-9)). These findings identified new genetic susceptibility alleles for lung cancer in never-smoking women in Asia and merit follow-up to understand their biological underpinnings.

Identification of new susceptibility loci for gastric non-cardia adenocarcinoma: pooled results from two Chinese genome-wide association studies.

OBJECTIVE: Although several genome-wide association studies (GWAS) of non-cardia gastric cancer have been published, more novel association signals could be exploited by combining individual studies together, which will further elucidate the genetic susceptibility of non-cardia gastric cancer. DESIGN: We conducted a meta-analysis of two published Chinese GWAS studies (2031 non-cardia gastric cancer cases and 4970 cancer-free controls) and followed by genotyping of additional 3564 cases and 4637 controls in two stages. RESULTS: The overall meta-analysis revealed two new association signals. The first was a novel locus at 5q14.3 and marked by rs7712641 (per-allele OR=0.84, 95% CI 0.80 to 0.88; p=1.21×10-11). This single-nucleotide polymorphism (SNP) marker maps to the intron of the long non-coding RNA, lnc-POLR3G-4 (XLOC_004464), which we observed has lower expression in non-cardia gastric tumour compared with matched normal tissue (Pwilcoxon signed-rank=7.20×10-4). We also identified a new signal at the 1q22 locus, rs80142782 (per-allele OR=0.62; 95% CI 0.56 to 0.69; p=1.71×10-19), which was independent of the previously reported SNP at the same locus, rs4072037 (per-allele OR=0.74; 95% CI 0.69 to 0.79; p=6.28×10-17). Analysis of the new SNP conditioned on the known SNP showed that the new SNP remained genome-wide significant (Pconditional=3.47×10-8). Interestingly, rs80142782 has a minor allele frequency of 0.05 in East Asians but is monomorphic in both European and African populations. CONCLUSION: These findings add new evidence for inherited genetic susceptibility to non-cardia gastric cancer and provide further clues to its aetiology in the Han Chinese population.

Common genetic variation and risk of gallbladder cancer in India: a case-control genome-wide association study.

BACKGROUND: Gallbladder cancer is highly lethal, with notable differences in incidence by geography and ethnic background. The aim of this study was to identify common genetic susceptibility alleles for gallbladder cancer. METHODS: In this case-control genome-wide association study (GWAS), we did a genome-wide scan of gallbladder cancer cases and hospital visitor controls, both of Indian descent, followed by imputation across the genome. Cases were patients aged 20-80 years with microscopically confirmed primary gallbladder cancer diagnosed or treated at Tata Memorial Hospital, Mumbai, India, and enrolled in the study between Sept 12, 2010, and June 8, 2015. We only included patients who had been diagnosed less than 1 year before the date of enrolment and excluded patients with any other malignancies. We recruited visitor controls aged 20-80 years with no history of cancer visiting all departments or units of Tata Memorial Hospital during the same time period and frequency matched them to cases on the basis of age, sex, and current region of residence. We estimated association using logistic regression, adjusting for age, sex, and five eigenvectors. We recruited samples for a replication cohort from patients visiting Tata Memorial Hospital between Aug 4, 2015, and May 17, 2016, and patients visiting the Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India, between July, 2010, and May, 2015. We used the same inclusion and exclusion criteria for the replication set. We examined three of the most significant single-nucleotide polymorphisms (SNPs) in the replication cohort and did a meta-analysis of the GWAS discovery and replication sets to get combined estimates of association. FINDINGS: The discovery cohort comprised 1042 gallbladder cancer cases and 1709 controls and the replication cohort contained 428 gallbladder cancer cases and 420 controls. We observed genome-wide significant associations for several markers in the chromosomal region 7q21.12 harbouring both the ABCB1 and ABCB4 genes, with the most notable SNPs after replication and meta-analysis being rs1558375 (GWAS p=3·8 × 10-9; replication p=0·01; combined p=2·3 × 10-10); rs17209837 (GWAS p=2·0 × 10-8; replication p=0·02; combined p=2·3 × 10-9), and rs4148808 (GWAS p=2·4 × 10-8; replication p=0·008; combined p=2·7 × 10-9). Combined estimates of per-allele trend odds ratios were 1·47 (95% CI 1·30-1·66; p=2·31 × 10-10) for rs1558375, 1·61 (1·38-1·89; p=2·26 × 10-9) for rs17209837, and 1·57 (1·35-1·82; p=2·71 × 10-9) for rs4148808. GWAS heritability analysis suggested that common variants are associated with substantial variation in risk of gallbladder cancer (sibling relative risk 3·15 [95% CI 1·80-5·49]). INTERPRETATION: To our knowledge, this study is the first report of common genetic variation conferring gallbladder cancer risk at genome-wide significance. This finding, along with in-silico and biological evidence indicating the potential functional significance of ABCB1 and ABCB4, underlines the likely importance of these hepatobiliary phospholipid transporter genes in the pathology of gallbladder cancer. FUNDING: The Tata Memorial Centre and Department of Biotechnology.

Myocardial relaxation is accelerated by fast stretch, not reduced afterload.

Fast relaxation of cross-bridge generated force in the myocardium facilitates efficient diastolic function. Recently published research studying mechanisms that modulate the relaxation rate has focused on molecular factors. Mechanical factors have received less attention since the 1980s when seminal work established the theory that reducing afterload accelerates the relaxation rate. Clinical trials using afterload reducing drugs, partially based on this theory, have thus far failed to improve outcomes for patients with diastolic dysfunction. Therefore, we reevaluated the protocols that suggest reducing afterload accelerates the relaxation rate and identified that myocardial relengthening was a potential confounding factor. We hypothesized that the speed of myocardial relengthening at end systole (end systolic strain rate), and not afterload, modulates relaxation rate and tested this hypothesis using electrically-stimulated trabeculae from mice, rats, and humans. We used load-clamp techniques to vary afterload and end systolic strain rate independently. Our data show that the rate of relaxation increases monotonically with end systolic strain rate but is not altered by afterload. Computer simulations mimic this behavior and suggest that fast relengthening quickens relaxation by accelerating the detachment of cross-bridges. The relationship between relaxation rate and strain rate is novel and upends the prevailing theory that afterload modifies relaxation. In conclusion, myocardial relaxation is mechanically modified by the rate of stretch at end systole. The rate of myocardial relengthening at end systole may be a new diagnostic indicator or target for treatment of diastolic dysfunction.

Integration of multiethnic fine-mapping and genomic annotation to prioritize candidate functional SNPs at prostate cancer susceptibility regions.

Interpretation of biological mechanisms underlying genetic risk associations for prostate cancer is complicated by the relatively large number of risk variants (n = 100) and the thousands of surrogate SNPs in linkage disequilibrium. Here, we combined three distinct approaches: multiethnic fine-mapping, putative functional annotation (based upon epigenetic data and genome-encoded features), and expression quantitative trait loci (eQTL) analyses, in an attempt to reduce this complexity. We examined 67 risk regions using genotyping and imputation-based fine-mapping in populations of European (cases/controls: 8600/6946), African (cases/controls: 5327/5136), Japanese (cases/controls: 2563/4391) and Latino (cases/controls: 1034/1046) ancestry. Markers at 55 regions passed a region-specific significance threshold (P-value cutoff range: 3.9 × 10(-4)-5.6 × 10(-3)) and in 30 regions we identified markers that were more significantly associated with risk than the previously reported variants in the multiethnic sample. Novel secondary signals (P < 5.0 × 10(-6)) were also detected in two regions (rs13062436/3q21 and rs17181170/3p12). Among 666 variants in the 55 regions with P-values within one order of magnitude of the most-associated marker, 193 variants (29%) in 48 regions overlapped with epigenetic or other putative functional marks. In 11 of the 55 regions, cis-eQTLs were detected with nearby genes. For 12 of the 55 regions (22%), the most significant region-specific, prostate-cancer associated variant represented the strongest candidate functional variant based on our annotations; the number of regions increased to 20 (36%) and 27 (49%) when examining the 2 and 3 most significantly associated variants in each region, respectively. These results have prioritized subsets of candidate variants for downstream functional evaluation.

Genome-wide association study identifies five susceptibility loci for follicular lymphoma outside the HLA region.

Genome-wide association studies (GWASs) of follicular lymphoma (FL) have previously identified human leukocyte antigen (HLA) gene variants. To identify additional FL susceptibility loci, we conducted a large-scale two-stage GWAS in 4,523 case subjects and 13,344 control subjects of European ancestry. Five non-HLA loci were associated with FL risk: 11q23.3 (rs4938573, p = 5.79 × 10(-20)) near CXCR5; 11q24.3 (rs4937362, p = 6.76 × 10(-11)) near ETS1; 3q28 (rs6444305, p = 1.10 × 10(-10)) in LPP; 18q21.33 (rs17749561, p = 8.28 × 10(-10)) near BCL2; and 8q24.21 (rs13254990, p = 1.06 × 10(-8)) near PVT1. In an analysis of the HLA region, we identified four linked HLA-DRß1 multiallelic amino acids at positions 11, 13, 28, and 30 that were associated with FL risk (pomnibus = 4.20 × 10(-67) to 2.67 × 10(-70)). Additional independent signals included rs17203612 in HLA class II (odds ratio [OR(per-allele)] = 1.44; p = 4.59 × 10(-16)) and rs3130437 in HLA class I (OR(per-allele) = 1.23; p = 8.23 × 10(-9)). Our findings further expand the number of loci associated with FL and provide evidence that multiple common variants outside the HLA region make a significant contribution to FL risk.