Cardiac Troponin I in Non- Acute Coronary Syndrome Patients with Chronic Kidney Disease

Objective

The aim of this study was to assess the results of troponin I (cTnI) in non- acute Coronary Syndrome (ACS) patients with chronic kidney disease (CKD). We also examined the risk factors for elevated cTnI in non-ACS patients with CKD and whether stage 5 CKD modifies the associations of elevated cTnI and the risk factors in non-ACS patients with CKD.

Methods

A retrospective study was performed. Logistic regression models were used.

Results

293 non-ACS patients with CKD were included in the current study. 43.34% non-ACS patients with CKD have an elevated cTnI level and 5.12% have an elevated cTnT level in MI range. In CKD patients without ACS and heart failure, only 26.03% (38/146) patients have an elevated cTnT level. In adjusted analyses, age, diastolic blood pressure and congestive heart failure is associated with an elevated cTnI level in non-ACS patients with CKD. Congestive heart failure is associated with an elevated cTnI level in non-ACS patients with CKD (OR 2.30, 95% CI 1.08,4.88, P=0.03). Stage 5 CKD does not modify the association of congestive heart failure and an elevated cTnI level.

Conclusion

43.34% non-ACS patients with CKD and 26.03% CKD patients without ACS and congestive heart failure have an elevated cTnI level. Congestive heart failure is associated with an elevated cTnI level in non-ACS patients with CKD. Stage 5 CKD does not modify the association of congestive heart failure and an elevated cTnI level.     

A Country-Wide Study of Spoligotype and Drug Resistance Characteristics of Mycobacterium tuberculosis Isolates from Children in China

Background

Tuberculosis (TB) is still a big threat to human health, especially in children. However, an isolation of Mycobacterium tuberculosis culture from pediatric cases remains a challenge. In order to provide some scientific basis for children TB control, we investigated the genotyping and drug resistance characteristics of M. tuberculosis isolates from pediatric cases in China.

Methodology/Principal Findings

In this study, a total of 440 strains including 90 from children (<15 years), 159 from adolescents (15–18 years) and 191 from adults (>18 years) isolated in 25 provinces across China were subjected to spoligotyping and drug susceptibility testing. As a result, Beijing family strains were shown to remain predominant in China (85.6%, 81.1% and 75.4% in three above groups, respectively), especially among new children cases (91.0% vs. 69.6% in previously treated cases, P = 0.03). The prevalence of the Beijing genotype isolates was higher in northern and central China in the total collection (85.1% in northern and 83.9% in central vs. 61.6% in southern China, P<0.001) and a similar trend was seen in all three age groups (P = 0.708, <0.001 and 0.025, respectively). In adolescents, the frequencies of isoniazid (INH)-resistant and ethambutol (EMB)-resistant isolates were significantly higher among Beijing strains compared to non-Beijing genotype strains (P = 0.028 for INH and P = 0.027 for EMB). Furthermore, strong association was observed between resistance to rifampicine (RIF), streptomycin (STR) and multidrug resistance (MDR) among Beijing compared to non-Beijing strains in previously treated cases of children (P = 0.01, 0.01 and 0.025, respectively).

Conclusion/Significance

Beijing family was more prevalent in northern and central China compared to southern China and these strains were predominant in all age groups. The genetic diversity of M. tuberculosis isolates from children was similar to that found in adolescents and adults. Beijing genotype was associated with RIF, STR and MDR resistance in previously treated children.     

Theoretical study on aluminum carbide endohedral fullerene-Al4C@C80

The possibility of a new endohedral fullerene with a trapped aluminum carbide cluster, Al₄C @C₈₀-I _h , was theoretical investigated. The geometries and electronic properties of it were investigated using density functional theory methods. The Al₄C unit formally transfers six electrons to the C₈₀ cage which induces stabilization of Al₄C@C₈₀. A favorable binding energy, relatively large HOMO-LUMO gap, electron affinities and ionization potentials suggested the Al₄C@C₈₀ is rather stable. The analysis of vertical ionization potential and vertical electron affinity indicate Al₄C@C₈₀ is a good electron acceptor.

Proteomic analysis for Type I interferon antagonism of Japanese encephalitis virus NS5 protein

Japanese encephalitis virus (JEV) nonstructural protein 5 (NS5) exhibits a Type I interferon (IFN) antagonistic function. This study characterizes Type I IFN antagonism mechanism of NS5 protein, using proteomic approach. In human neuroblastoma cells, NS5 expression would suppress IFNβ‐induced responses, for example, expression of IFN‐stimulated genes PKR and OAS as well as STAT1 nuclear translocation and phosphorylation. Proteomic analysis showed JEV NS5 downregulating calreticulin, while upregulating cyclophilin A, HSP 60 and stress‐induced‐phosphoprotein 1. Gene silence of calreticulin raised intracellular Ca²⁺ levels while inhibiting nuclear translocalization of STAT1 and NFAT‐1 in response to IFNβ, thus, indicating calreticulin downregulation linked with Type I IFN antagonism of JEV NS5 via activation of Ca²⁺/calicineurin. Calcineurin inhibitor cyclosporin A attenuated NS5‐mediated inhibition of IFNβ‐induced responses, for example, IFN‐sensitive response element driven luciferase, STAT1‐dependent PKR mRNA expression, as well as phosphorylation and nuclear translocation of STAT1. Transfection with calcineurin (vs. control) siRNA enhanced nuclear translocalization of STAT1 and upregulated PKR expression in NS5‐expressing cells in response to IFNβ. Results prove Ca²⁺, calreticulin, and calcineurin involvement in STAT1‐mediated signaling as well as a key role of JEV NS5 in Type I IFN antagonism. This study offers insights into the molecular mechanism of Type I interferon antagonism by JEV NS5.     

Amino‐functionalized macroporous silica for efficient tryptic digestion in acidic solutions

Amino‐functionalized macroporous silica foam (NH₂‐MOSF) has been developed as a host reactor to realize highly efficient proteolysis in acidic solutions where normal tryptic reactions cannot occur. The digestion protocol consists simply of adding the functionalized NH₂‐MOSF into the protein and trypsin solutions without altering the bulk pH or preloading the enzymes on the materials. With this protocol, digestion of sample fractions from LC can be efficiently realized in the acidic solutions directly. Digestion of a protein fraction extracted from rat liver tissue after LC separation was performed to illustrate this principle, where 103 proteins were successfully identified at pH 3 after 1.5 h of tryptic digestion.     

Prediction of Drug-Target Interactions for Drug Repositioning Only Based on Genomic Expression Similarity

Small drug molecules usually bind to multiple protein targets or even unintended off-targets. Such drug promiscuity has often led to unwanted or unexplained drug reactions, resulting in side effects or drug repositioning opportunities. So it is always an important issue in pharmacology to identify potential drug-target interactions (DTI). However, DTI discovery by experiment remains a challenging task, due to high expense of time and resources. Many computational methods are therefore developed to predict DTI with high throughput biological and clinical data. Here, we initiatively demonstrate that the on-target and off-target effects could be characterized by drug-induced in vitro genomic expression changes, e.g. the data in Connectivity Map (CMap). Thus, unknown ligands of a certain target can be found from the compounds showing high gene-expression similarity to the known ligands. Then to clarify the detailed practice of CMap based DTI prediction, we objectively evaluate how well each target is characterized by CMap. The results suggest that (1) some targets are better characterized than others, so the prediction models specific to these well characterized targets would be more accurate and reliable; (2) in some cases, a family of ligands for the same target tend to interact with common off-targets, which may help increase the efficiency of DTI discovery and explain the mechanisms of complicated drug actions. In the present study, CMap expression similarity is proposed as a novel indicator of drug-target interactions. The detailed strategies of improving data quality by decreasing the batch effect and building prediction models are also effectively established. We believe the success in CMap can be further translated into other public and commercial data of genomic expression, thus increasing research productivity towards valid drug repositioning and minimal side effects.     

Ab Initio Modeling and Experimental Assessment of Janus Kinase 2 (JAK2) Kinase-Pseudokinase Complex Structure

The Janus Kinase 2 (JAK2) plays essential roles in transmitting signals from multiple cytokine receptors, and constitutive activation of JAK2 results in hematopoietic disorders and oncogenesis. JAK2 kinase activity is negatively regulated by its pseudokinase domain (JH2), where the gain-of-function mutation V617F that causes myeloproliferative neoplasms resides. In the absence of a crystal structure of full-length JAK2, how JH2 inhibits the kinase domain (JH1), and how V617F hyperactivates JAK2 remain elusive. We modeled the JAK2 JH1–JH2 complex structure using a novel informatics-guided protein-protein docking strategy. A detailed JAK2 JH2-mediated auto-inhibition mechanism is proposed, where JH2 traps the activation loop of JH1 in an inactive conformation and blocks the movement of kinase αC helix through critical hydrophobic contacts and extensive electrostatic interactions. These stabilizing interactions are less favorable in JAK2-V617F. Notably, several predicted binding interfacial residues in JH2 were confirmed to hyperactivate JAK2 kinase activity in site-directed mutagenesis and BaF3/EpoR cell transformation studies. Although there may exist other JH2-mediated mechanisms to control JH1, our JH1–JH2 structural model represents a verifiable working hypothesis for further experimental studies to elucidate the role of JH2 in regulating JAK2 in both normal and pathological settings.     

Lysine-Specific Demethylase 1 in Breast Cancer Cells Contributes to the Production of Endogenous Formaldehyde in the Metastatic Bone Cancer Pain Model of Rats

Background

Bone cancer pain seriously affects the quality of life of cancer patients. Our previous study found that endogenous formaldehyde was produced by cancer cells metastasized into bone marrows and played an important role in bone cancer pain. However, the mechanism of production of this endogenous formaldehyde by metastatic cancer cells was unknown in bone cancer pain rats. Lysine-specific demethylase 1 (LSD1) is one of the major enzymes catalyzing the production of formaldehyde. The expression of LSD1 and the concentration of formaldehyde were up-regulated in many high-risk tumors.

Objective

This study aimed to investigate whether LSD1 in metastasized MRMT-1 breast cancer cells in bone marrows participated in the production of endogenous formaldehyde in bone cancer pain rats.

Methodology/Principal Findings

Concentration of the endogenous formaldehyde was measured by high performance liquid chromatography (HPLC). Endogenous formaldehyde dramatically increased in cultured MRMT-1 breast cancer cells in vitro, in bone marrows and sera of bone cancer pain rats, in tumor tissues and sera of MRMT-1 subcutaneous vaccination model rats in vivo. Formaldehyde at a concentration as low as the above measured (3 mM) induced pain behaviors in normal rats. The expression of LSD1 which mainly located in nuclei of cancer cells significantly increased in bone marrows of bone cancer pain rats from 14 d to 21 d after inoculation. Furthermore, inhibition of LSD1 decreased the production of formaldehyde in MRMT-1 cells in vitro. Intraperitoneal injection of LSD1 inhibitor pargyline from 3 d to 14 d after inoculation of MRMT-1 cancer cells reduced bone cancer pain behaviors.

Conclusion

Our data in the present study, combing our previous report, suggested that in the endogenous formaldehyde-induced pain in bone cancer pain rats, LSD1 in metastasized cancer cells contributed to the production of the endogenous formaldehyde.     

A Genome-Wide Scan for Breast Cancer Risk Haplotypes among African American Women

Genome-wide association studies (GWAS) simultaneously investigating hundreds of thousands of single nucleotide polymorphisms (SNP) have become a powerful tool in the investigation of new disease susceptibility loci. Haplotypes are sometimes thought to be superior to SNPs and are promising in genetic association analyses. The application of genome-wide haplotype analysis, however, is hindered by the complexity of haplotypes themselves and sophistication in computation. We systematically analyzed the haplotype effects for breast cancer risk among 5,761 African American women (3,016 cases and 2,745 controls) using a sliding window approach on the genome-wide scale. Three regions on chromosomes 1, 4 and 18 exhibited moderate haplotype effects. Furthermore, among 21 breast cancer susceptibility loci previously established in European populations, 10p15 and 14q24 are likely to harbor novel haplotype effects. We also proposed a heuristic of determining the significance level and the effective number of independent tests by the permutation analysis on chromosome 22 data. It suggests that the effective number was approximately half of the total (7,794 out of 15,645), thus the half number could serve as a quick reference to evaluating genome-wide significance if a similar sliding window approach of haplotype analysis is adopted in similar populations using similar genotype density.