Unusual interlayer quantum transport behavior caused by the zeroth Landau level in YbMnBi2

Relativistic fermions in topological quantum materials are characterized by linear energy-momentum dispersion near band crossing points. Under magnetic fields, relativistic fermions acquire Berry phase of π in cyclotron motion, leading to a zeroth Landau level (LL) at the crossing point, a signature unique to relativistic fermions. Here we report the unusual interlayer quantum transport behavior resulting from the zeroth LL mode observed in the time reversal symmetry breaking type II Weyl semimetal YbMnBi2. The interlayer magnetoresistivity and Hall conductivity of this material are found to exhibit surprising angular dependences under high fields, which can be well fitted by a model, which considers the interlayer quantum tunneling transport of the zeroth LL's Weyl fermions. Our results shed light on the unusual role of zeroth LLl mode in transport.The transport behavior of the carriers residing in the lowest Landau level is hard to observe in most topological materials. Here, Liu et al. report a surprising angular dependence of the interlayer magnetoresistivity and Hall conductivity arising from the lowest Landau level under high magnetic field in type II Weyl semimetal YbMnBi2.

[Analysis of infection and drug-resistance in 6 107 cases of extrapulmonary tuberculosis in Chengdu area]

Objective: To analyze the infection and drug resistance of extrapulmonary tuberculosis, in order to provide useful references for prevention and treatment of tuberculosis (TB). Methods: A total of 6 107 suspected cases of extrapulmonary tuberculosis, including lymph node, pleural, peritoneal, meningeal, urinary tract, and bone tuberculosis, were collected retrospectively from January 2013 to December 2015 in Public Health Clinical Center of Chengdu. There were 4 033 male and 2 074 female patients, and the average age was 37 years.The epidemiological data, infection and drug resistance were analyzed statistically. Results: There were 21 036 cases of mycobacterial culture from January 2013 to December 2015, of which 7 119 were positive(33.8%). Extrapulmonary tuberculosis was found in 6 107 cases, of which 896 were positive, accounting for 12.6% of the positive cases(896/7 119). Culture-positive cases of extra-pulmonary tuberculosis showed a rising trend from 2013 to 2015 (n=174, 310, 421, respectively), and the annual average increasing rate was over 50%.Cases were distributed at younger ages (21-40 years), with an average age of 34 years.There were more male patients, with a male to female ratio of 2.1∶1. The most common site of extrapulmonary tuberculosis was the bone(62/243, 25.5%), followed by lymph node(283/1 297, 21.8%), pleural(289/1 840, 15.7%), urinary tract(63/452, 13.9%), peritoneum(41/303, 13.5%), meningeal(156/1 915, 8.1%)and other types of tuberculosis(2/57, 3.5%). Drug sensitivity test of 896 extrapulmonary tuberculosis strains showed that the resistance rate (from high to low) was in the order of isoniazid, rifampicin, streptomycin, ofloxacin, ciprofloxacin, amikacin, capreomycin and ethambutol. Multidrug-resistant(MDR)and extremely-drug resistant (XDR) rate was 9.7 %(87/896)and 2.0%(17/896)respectively. Conclusions: Cases of extrapulmonary tuberculosis sent for bacterial culture and the positive rate showed a rising trend by years in Chengdu area.The drug resistance level was higher than that reported both in China and abroad.The prevention and treatment of extrapulmonary tuberculosis should be strengthened in this area.

[DNA damage associated genetic variants contribute to lung cancer susceptibility in a Han Chinese population]

OBJECTIVE

To explore the association between DNA damage-related genetic variants and lung cancer susceptibility in a Han Chinese population.

METHODS

This case-control study enrolled patients from the Cancer Hospital of Jiangsu Province and Jiangsu Province Hospital from 2003 to 2009. Controls were randomly selected from individuals who visited the same hospital or a community-based health examination program during the same time period. A 5 ml venous blood sample was obtained from each participant and epidemiological information was collected on a standard questionnaire. Illumina Infinium(®) BeadChip was used for genotyping of 35 DNA damage-related single nucleotide variations (SNVs), which were identified in our previous study. Multivariate and binary logistic regressions were used to calculate the OR and 95%CI for lung cancer risk. HaploReg V4.1 and Regulome DB were used to understand functional annotation on important SNV.

RESULTS

The distributions of age (61.06±10.15) vs. (61.32±11.07) years; t=-0.72, P=0.473) and sex (χ(2)=1.81, P=0.179) were similar between cases and controls. However, the case group had a higher frequency of smokers (61.08% vs. 48.54%; χ(2)=50.04, P<0.001) and heavy smokers (42.28% vs. 24.07%; χ(2)=122.32, P<0.001). Among the 34 SNVs that passed quality control, two SNVs were significantly associated with lung cancer risk after adjustments for age, sex and cumulative smoking dose: rs9267576 C>A (CA genotype/CC genotype, OR=1.56, 95% CI: 1.01-2.40) and rs3130683 A>G (AG genotype/AA genotype, OR=1.87, 95%CI: 1.13-3.09). After step-wise logistic regression analysis, only the rs3130683 SNV was retained in the model, indicating that the association between rs9267576 and lung cancer may be due to the effect of rs3130683. Functional annotation indicated that rs3130683 was located in the promoter and enhancer regions, and was an expression quantitative trait loci of HLA. The Cancer Genome Atlas indicated that expression of HLA-C, DQB1, DRB1 and DRB5 in lung cancer tissue was significantly lower than in paired normal tumor-adjacent tissue, with down-regulation of the four respective genes in 81.3%, 88.8%, 90.7% and 90.7% of lung cancer tissues (P-values were 6.68×10(-15), 2.21×10(-13), 2.20×10(-16), 2.58×10(-13), respectively).

CONCLUSIONS

The SNV rs3130683 (A>G) was associated with the risk of lung cancer in a Han Chinese population. This SNV may affect the risk of lung cancer by regulating HLA expression.

Impact of gain-of-function mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) on glucose and lipid homeostasis

LRP5 loss-of-function mutations have been shown to cause profound osteoporosis and have been associated with impaired insulin sensitivity and dysregulated lipid metabolism. We hypothesized that gain-of-function mutations in LRP5 would also affect these parameters. We therefore studied individuals with LRP5 gain-of-function mutations exhibiting high bone mass (HBM) phenotypes and found that while there was no detected change in insulin sensitivity, there was a significant reduction in serum LDL.

INTRODUCTION

Wnt signaling through LRP5 represents a newly appreciated metabolic pathway, which potentially represents a target for drug discovery in type 2 diabetes and hyperlipidemia. Studies in animal models suggest a physiologic link between LRP5 and glucose and lipid homeostasis; however, whether it plays a similar role in humans is unclear. As current literature links loss-of-function LRP5 to impaired glucose and lipid metabolism, we hypothesized that individuals with an HBM-causing mutation in LRP5 would exhibit improved glucose and lipid homeostasis. Since studies in animal models have suggested that Wnt signaling augments insulin secretion, we also examined the effect of Wnt signaling on glucose-stimulated insulin secretion on human pancreatic islets.

METHODS

This was a matched case-control study. We used several methods to assess glucose and lipid metabolism in 11 individuals with HBM-causing mutations in LRP5. Affected study participants were recruited from previously identified kindreds with HBM-causing LRP5 mutations and included 9 males and 2 females. Two subjects that were being treated with insulin for type 2 diabetes were excluded from our analysis, as this would have obscured our ability to determine the impact of gain-of-function LRP5 mutations on glucose metabolism. The mean age of the evaluated study subjects was 55 ± 7 with a mean BMI of 27.2 ± 2.0. Control subjects were matched and recruited from the general community at an equivalent ratio, with 18 males and 4 females (mean age 56 ± 4; mean BMI 27.2 ± 1.0). Study testing was conducted at an academic medical center.

RESULTS

There were no statistically significant differences between affected and matched control populations for HbA1c (p = 0.06), eAG (p = 0.06), insulin (p = 0.82), HOMA-B (p = 0.34), or HOMA-IR (p = 0.66). The mean Insulin Sensitivity Index (ISI) was also similar between control and affected individuals. Total cholesterol (p = 0.43), triglycerides (TG) (p = 0.56), and HDL (p = 0.32) were not different between the same two groups. In a small subset of studied subjects, intramyocellular and hepatic lipid content were similar in the affected individuals and controls when quantified by proton magnetic resonance spectroscopy (MRS). However, the mean value for serum LDL was significantly lower (p = 0.04) in affected individuals. In primary human islets, there were no differences between control and Wnt treatment groups for insulin secretion measured as area under the curve (AUC) for first phase (p = 0.17) or second phase (p = 0.33) insulin secretion.

CONCLUSIONS

Although our sample size was small, our data do not support the hypothesis that HBM-causing LRP5 mutations, associated with increased Wnt signaling, improve glucose metabolism in humans. However, it does appear that LRP5 variants may affect LDL metabolism, a major risk factor for coronary artery disease. The molecular mechanisms underpinning this effect warrant further study.

Effect of PM2.5 mediated oxidative stress on the innate immune cellular response of Der p1 treated human bronchial epithelial cells

OBJECTIVE

To investigate the effect of stimulation of Human Bronchial Epithelial Cells (HBEC) by Der p1 and PM2.5 on the expression of innate immune cell factors to find new therapeutic targets for treatment of bronchial asthma.

MATERIALS AND METHODS

The Der p1 antigen exposure model in the HEBC line, 16HBE-14o, was established in vitro. PM2.5 at a concentration of 50 µM/cm2, was added to these cells for 0.5 h, 1 h, 2 h and 3 h. Cells were treated with the following reagents for the indicated times: 300 ng/mL Der p1 for 21 h, 50 µM/cm2 PM2.5 for 3 h, 10 mM Nac for 3 h and PM2.5 contamination for 3 h. The experiment was divided into five groups: control (group A), Der p1 exposure group (group B), PM2.5 treated group (group C), PM2.5+Der p1 exposure group (group D), Nac+PM2.5+Der p1 exposure group (group E). ELISA method was adopted to test the expression levels of malondialdehyde, IL-25, IL-33 and thymic stromal lymphopoietin (TSLP), and Real-time RT-PCT was used to measure IL-25, IL-33 and TSLP mRNA.

RESULTS

The protein and mRNA levels of malondialdehyde, IL-25, IL-33 and TSLP in group D were significantly higher than those in the other groups, while the protein and mRNA levels of malondialdehyde, IL-25, IL-33 and TSLP in group E were significantly lower than those in group D (p<0.05).

CONCLUSIONS

PM2.5 can enhance the Der p1 antigen-induced HBEC innate immune response through the expression of IL-25, IL-33 and TSLP, which may exacerbate the occurrence rate of bronchial asthma.

Genetic variation and genetic structure of five Chinese indigenous pig populations in Jiangsu Province revealed by sequencing data

In this study, we investigated the genetic variants, including SNPs and indels (short insertions or deletions, less than 50 bp in length), in the genomes and genetic structures of five pig populations (in the northern Taihu Lake region, Jiangsu Province) using the genotyping by genome reducing and sequencing (GGRS) approach. A total of 581 million good reads with an average depth of 11× and an average coverage of 2.16% were used to call variants. In general, 202 106 SNPs and 34 415 indels were obtained, of which 2690 SNPs and 224 indels were capable of inducing protein‐coding changes. The genes containing these variants were extracted for functional annotation. The results of gene enrichment analysis revealed that the SNPs under investigation may be associated with reproduction, disease resistance, meat quality and adipose tissue traits, whereas the indels were associated mainly with adipose tissue and disease. Analysis of the genetic structure showed that each population displayed comparable, large differentiations from the others, indicating their uniqueness. In conclusion, the results of our study provide the first genomic overview of the genetic variants and population structures of five Chinese indigenous pig populations.

Immune complexes induce TNF-α and BAFF production from U937 cells by HMGB1 and RAGE

OBJECTIVE

This study investigated the effects of immune complexes (ICs) on tumor necrosis factor α (TNF-α) and B cell-activating factor (BAFF) production from U937 cells and further explored the mechanism.

MATERIALS AND METHODS

U937 cells were incubated with necrosis supernatant or systemic lupus erythematosus (SLE) sera alone, or their combination. The expression of TNF-α and BAFF was determined by Real-time polymerase chain reaction and enzyme-linked immunosorbent assay. High mobility group box protein 1(HMGB1) A-box was produced by gene recombination. HMGB1 A-box and anti-receptor for advanced glycation end products (RAGE) antibody were adopted in the blocking experiments. The importance of DNA for cytokine induction was investigated by DNase treatment.

RESULTS

The combination of necrosis supernatant and SLE sera induced the expression of TNF-α and BAFF significantly increased compared to necrosis supernatant or SLE sera alone. Recombinant HMGB1 A-box protein was purified, and TNF-α and BAFF production, which were induced by this combination, was blocked via HMGB1 A-box and anti-RAGE antibody. Moreover, we found that DNA component is important for the immunostimulatory activity of this combination.

CONCLUSIONS

ICs containing DNA can promote TNF-α and BAFF production in U937 cells, and this process can be mediated by HMGB1 and RAGE. One possible mechanism of increasing BAFF production in SLE is proposed in this study whereby B cell activation, antibody production and ICs stimulated monocytes may create a vicious cycle that leads to B cell hyperactivity, which can be of importance for SLE etiopathogenesis.