A Hypomorphic Lsd1 Allele Results in Heart Development Defects in Mice

Lysine-specific demethylase 1 (Lsd1/Aof2/Kdm1a), the first enzyme with specific lysine demethylase activity to be described, demethylates histone and non-histone proteins and is essential for mouse embryogenesis. Lsd1 interacts with numerous proteins through several different domains, most notably the tower domain, an extended helical structure that protrudes from the core of the protein. While there is evidence that Lsd1-interacting proteins regulate the activity and specificity of Lsd1, the significance and roles of such interactions in developmental processes remain largely unknown. Here we describe a hypomorphic Lsd1 allele that contains two point mutations in the tower domain, resulting in a protein with reduced interaction with known binding partners and decreased enzymatic activity. Mice homozygous for this allele die perinatally due to heart defects, with the majority of animals suffering from ventricular septal defects. Molecular analyses revealed hyperphosphorylation of E-cadherin in the hearts of mutant animals. These results identify a previously unknown role for Lsd1 in heart development, perhaps partly through the control of E-cadherin phosphorylation.     

Identification and Effect Decomposition of Risk Factors for Brucella Contamination of Raw Whole Milk in China

Background

Lack of clear risk factor identification is the main reason for the persistence of brucellosis infection in the Chinese population, and there has been little assessment of the factors contributing to Brucella contamination of raw whole milk. The purpose of this study was to identify risk factors affecting Brucella contamination of raw milk, and to evaluate effective measures for disease reduction in order to determine preventive strategies.

Methods and Findings

A nationwide survey was conducted and samples were obtained from 5211 cows corresponding to 25 sampling locations throughout 15 provinces in China. The prevalence of Brucella in the raw milk samples averaged 1.07% over the 15 Chinese provinces, while the prevalence of positive areas within these regions ranged from 0.23–3.84% among the nine provinces with positive samples. The survey examined factors that supposedly influence Brucella contamination of raw whole milk, such as management style, herd size, abortion rate, hygiene and disease control practices. A binary logistic regression analysis was carried out to determine the association between risk factors for Brucella and contamination of milk samples. Furthermore, a relative effect decomposition study was conducted to determine effective strategies for reducing the risk of Brucella contamination of raw whole milk. Our data indicate that disease prevention and control measures, abortion rate, and animal polyculture are the most important risk factors. Meanwhile, culling after quarantine was identified as an effective protective measure in the current Chinese dairy situation.

Conclusions

These results indicate that, although there is a low risk of contamination of milk with Brucella nationwide in China, there are individual regions where contamination is a significant problem. Controlling three factors–culling after quarantine, maintaining a low abortion rate, and avoiding mixing groups of cattle and small ruminants–could effectively reduce the risk of Brucella contamination of raw whole milk.     

Single-Row or Double-Row Fixation Technique for Full-Thickness Rotator Cuff Tears: A Meta-Analysis

Background

The single-row and double-row fixation techniques have been widely used for rotator cuff tears. However, whether the double-row technique produces superior clinical or anatomic outcomes is still considered controversial. This study aims to use meta-analysis to compare the clinical and anatomical outcomes between the two techniques.

Methods

The Pubmed, Embase, and Cochrane library databases were searched for relevant studies published before November 1, 2012. Studies clearly reporting a comparison of the single-row and double-row techniques were selected. The Constant, ASES, and UCLA scale systems and the rotator cuff integrity rate were evaluated. The weighted mean differences and relative risks were calculated using a fixed-effects or random-effects model.

Results

Eight studies were included in this meta-analysis. The weighted mean differences of the ASES (−0.84; P = 0.04; I² = 0%) and UCLA (−0.75; P = 0.007; I² = 0%) scales were significantly low in the single-row group for full-thickness rotator cuff tears. For tear sizes smaller than 3 cm, no significant difference was found between the groups no matter in Constant (P = 0.95; I² = 0%), ASES (P = 0.77; I² = 0%), or UCLA (P = 0.24; I² = 13%) scales. For tear sizes larger than 3 cm, the ASES (−1.95; P = 0.001; I² = 49%) and UCLA (−1.17; P = 0.006; I² = 0%) scales were markedly lower in the single-row group. The integrity of the rotator cuff (0.81; P = 0.0004; I² = 10%) was greater and the partial thickness retear rate (1.93; P = 0.007; I² = 10%) was less in the double-row group. Full-thickness retears showed no difference between the groups (P = 0.15; I² = 0%).

Conclusion

The meta-analysis suggests that the double-row fixation technique increases post-operative rotator cuff integrity and improves the clinical outcomes, especially for full-thickness rotator cuff tears larger than 3 cm. For tear sizes smaller than 3 cm, there was no difference in the clinical outcomes between the two techniques.

Level of Evidence

Level I.     

Transgenic Overexpression of Ephrin B1 in Bone Cells Promotes Bone Formation and an Anabolic Response to Mechanical Loading in Mice

To test if ephrin B1 overexpression enhances bone mass, we generated transgenic mice overexpressing ephrin B1 under the control of a 3.6 kb rat collagen 1A1 promoter (Col3.6-Tg^efnb1). Col3.6-Tg^efnb1 mice express 6-, 12- and 14-fold greater levels of full-length ephrin B1 protein in bone marrow stromal cells, calvarial osteoblasts, and osteoclasts, respectively. The long bones of both genders of Col3.6-Tg^efnb1 mice have increased trabecular bone volume, trabecular number, and trabecular thickness and decreased trabecular separation. Enhanced bone formation and decreased bone resorption contributed to this increase in trabecular bone mass in Col3.6-Tg^efnb1 mice. Consistent with these findings, our in vitro studies showed that overexpression of ephrin B1 increased osteoblast differentiation and mineralization, osterix and collagen 1A1 expression in bone marrow stromal cells. Interaction of ephrin B1 with soluble clustered EphB2-Fc decreased osteoclast precursor differentiation into multinucleated cells. Furthermore, we demonstrated that the mechanical loading-induced increase in EphB2 expression and newly formed bone were significantly greater in the Col3.6-Tg^efnb1 mice than in WT littermate controls. Our findings that overexpression of ephrin B1 in bone cells enhances bone mass and promotes a skeletal anabolic response to mechanical loading suggest that manipulation of ephrin B1 actions in bone may provide a means to sensitize the skeleton to mechanical strain to stimulate new bone formation.     

Moderate Alcohol Use and Cardiovascular Disease from Mendelian Randomization

Background

Observational studies show moderate alcohol use negatively associated with ischemic heart disease (IHD) and cardiovascular disease (CVD). However, healthier attributes among moderate users compared to never users may confound the apparent association. A potentially less biased way to examine the association is Mendelian randomization, using alcohol metabolizing genes which influence alcohol use.

Methods

We used instrumental variable analysis with aldehyde dehydrogenase 2 (ALDH2) genotypes (AA/GA/GG) as instrumental variables for alcohol use to examine the association of alcohol use (10 g ethanol/day) with CVD risk factors (blood pressure, lipids and glucose) and morbidity (self-reported IHD and CVD) among men in the Guangzhou Biobank Cohort Study.

Results

ALDH2 genotypes were a credible instrument for alcohol use (F-statistic 74.6). Alcohol was positively associated with HDL-cholesterol (0.05 mmol/L per alcohol unit, 95% confidence interval (CI) 0.02 to 0.08) and diastolic blood pressure (1.15 mmHg, 95% CI 0.23 to 2.07) but not with systolic blood pressure (1.00 mmHg, 95% CI -0.74 to 2.74), LDL-cholesterol (0.03 mmol/L, 95% CI -0.03 to 0.08), log transformed triglycerides (0.03 mmol/L, 95% CI -0.01 to 0.08) or log transformed fasting glucose (0.01 mmol/L, 95% CI -0.006 to 0.03), self-reported CVD (odds ratio (OR) 0.98, 95% CI 0.76 to 1.27) or self-reported IHD (OR 1.10, 95% CI 0.83 to 1.45).

Conclusion

Low to moderate alcohol use among men had the expected effects on most CVD risk factors but not fasting glucose. Larger studies are needed to confirm the null associations with IHD, CVD and fasting glucose.     

Esophageal Squamous Cell Carcinoma and Gastric Cardia Adenocarcinoma Shared Susceptibility Locus in PLCE1: A Meta-Analysis

Background And Objective

Two recent genome-wide association studies have identified a shared susceptibility variation PLCE1 rs2274223 for esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinomas (GCA). Subsequent case-control studies have reported this association in other populations. However, the findings were controversial and the effect remains undetermined. Our aim is to provide a precise quantification of the association between PLCE1 rs2274223 variation and the risk of ESCC and GCA.

Methods

Studies were identified by a literature search in MEDLINE and EMBASE databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association in allele, dominant, recessive, homozygous, and heterozygous models.

Results

Ten articles were identified, including 22156 ESCC cases and 28803 controls, 5197 GCA cases and 17613 controls. Overall, PLCE1 rs2274223 G allele (G vs. A: OR=1.26, 95% CI: 1.15-1.39 for ESCC; OR=1.51, 95% CI: 1.35–1.69 for GCA) and its carrier (GG +AG vs. AA: OR = 1.23; 95% CI =1.02-1.49 for ESCC; OR =1.62; 95% CI =1.15-2.29 for GCA) were significantly associated with the risk of ESCC and GCA. In stratified analysis by ethnicity, significant association of PLCE1 rs2274223 G allele and the risk of ESCC (OR=1.33, 95% CI 1.21–1.45) and GCA (OR =1.56, 95% CI: 1.47-1.64) was observed in Chinese population.

Conclusions

Our meta-analysis results indicated that PLCE1 rs2274223 G allele significantly contributed to the risk of ESCC and GCA, especially in Chinese population.     

Host-Specific Phenotypic Plasticity of the Turtle Barnacle Chelonibia testudinaria: A Widespread Generalist Rather than a Specialist

Turtle barnacles are common epibionts on marine organisms. Chelonibia testudinaria is specific on marine turtles whereas C. patula is a host generalist, but rarely found on turtles. It has been questioned why C. patula, being abundant on a variety of live substrata, is almost absent from turtles. We evaluated the genetic (mitochondrial COI, 16S and 12S rRNA, and amplified fragment length polymorphism (AFLP)) and morphological differentiation of C. testudinaia and C. patula from different hosts, to determine the mode of adaptation exhibited by Chelonibia species on different hosts. The two taxa demonstrate clear differences in shell morphology and length of 4–6^th cirri, but very similar in arthropodal characters. Moreover, we detected no genetic differentiation in mitochondrial DNA and AFLP analyses. Outlier detection infers insignificant selection across loci investigated. Based on combined morphological and molecular evidence, we proposed that C. testudinaria and C. patula are conspecific, and the two morphs with contrasting shell morphologies and cirral length found on different host are predominantly shaped by developmental plasticity in response to environmental setting on different hosts. Chelonibia testudinaria is, thus, a successful general epibiotic fouler and the phenotypic responses postulated can increase the fitness of the animals when they attach on hosts with contrasting life-styles.     

Pyrosequencing to Identify Homogeneous Phenomenon When Using Recipients/Donors with Different CYP3A5*3 Genotypes in Living Donor Liver Transplantation

This study used pyrosequencing to determine the proportional distribution of CYP3A5*3 genotypes to further confirm the homogeneous phenomenon that is observed when recipients and donors in living donor liver transplantation (LDLT) have a different single nucleotide polymorphism (SNP) genotype. We enrolled 42 recipient/living donor pairs and the SNPs of CYP3A5*3 were identified by polymerase chain reaction-restriction fragment length polymorphism. We performed 120 liver graft biopsies as part of clinical investigations after LDLT. Pyrosequencing of the CYP3A5*3 SNPs revealed that among the 16 recipients with the G/G genotype, 94.68% had the G and 5.32% the A allele. Among the 14 recipients with the A/G genotype, 78.08% had the G and 21.92% the A allele, and among the 12 recipients with the A/A genotype, 18.45% had the G and 81.55% the A allele. Among the 12 donors with the G/G genotype, 93.85% had the G and 6.14% the A allele. Among the 26 donors with the A/G genotype, 75.73% had the G and 24.27% the A allele, and among the 4 donors with the A/A genotype, 11.09% had the G and 88.91% the A allele. There were a total of 120 liver graft biopsy samples; among the 37 recipients with the G/G genotype, 89.74% had the G and 10.26% the A allele, among the 70 recipients with the A/G genotype, 71.57% had the G and 28.43% the A allele, and among the 13 recipients with the A/A genotype, 48.25% had the G and 51.75% the A allele. The proportional distribution of G and A alleles of the CYP3A5*3 SNP between recipients/donors and liver grafts after LDLT was significantly different (p<0.001). Pyrosequencing was useful in identifying detailed proportional changes of the CYP3A5*3 SNP allele distribution, and to confirm the homogeneous phenomenon when recipients and donors in LDLT have a different genotype.     

GSTP1 Ile105Val Polymorphism and Prostate Cancer Risk: Evidence from a Meta-Analysis

Background

Glutathione S-transferase P1 (GSTP1) is thought to be involved in the detoxification of reactive carcinogen metabolites. Numerous epidemiological studies have evaluated the association of GSTP1 Ile105Val polymorphism with the risk of prostate cancer. However, the results remain inconclusive. To derive a more precise estimation, a meta-analysis was performed.

Methodology/Principal Findings

A comprehensive search was conducted to identify the eligible studies. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the relationship. The overall association was not significant (Val/Val vs. Ile/Ile OR = 1.06, 95% CI = 0.90–1.25, P = 0.50; Val/Val vs. Val/Ile+Ile/Ile: OR = 1.07, 95% CI = 0.91–1.25, P = 0.44). In subgroup analyses by ethnicity and prostate cancer grade, the similar results were observed. However, in stratified analysis by clinical stage, we found a significant association with low-stage prostate cancer (Val/Val vs. Ile/Ile: OR = 2.70, 95% CI = 1.73–4.22, P<0.001; Val/Val vs. Val/Ile+Ile/Ile: OR = 2.14, 95% CI = 1.38–3.33, P = 0.001). Moreover, there was no statistically significant evidence of multiplicative interactions neither between the GSTP1 Ile105Val polymorphism and GSTM1, nor between smoking status and GSTP1 on prostate cancer risk.

Conclusions

This meta-analysis showed that GSTP1 Ile105Val polymorphism might not be significantly associated with overall prostate cancer risk. Further stratified analyses showed a significant association with low-stage prostate cancer.