Arabidopsis Transporter MGT6 Mediates Magnesium Uptake and Is Required for Growth under Magnesium Limitation

Although magnesium (Mg²⁺) is the most abundant divalent cation in plant cells, little is known about the mechanism of Mg²⁺ uptake by plant roots. Here, we report a key function of Magnesium Transport6 (MGT6)/Mitochondrial RNA Splicing2-4 in Mg²⁺ uptake and low-Mg²⁺ tolerance in Arabidopsis thaliana. MGT6 is expressed mainly in plant aerial tissues when Mg²⁺ levels are high in the soil or growth medium. Its expression is highly induced in the roots during Mg²⁺ deficiency, suggesting a role for MGT6 in response to the low-Mg²⁺ status in roots. Silencing of MGT6 in transgenic plants by RNA interference (RNAi) resulted in growth retardation under the low-Mg²⁺ condition, and the phenotype was restored to normal growth after RNAi plants were transferred to Mg²⁺-sufficient medium. RNAi plants contained lower levels of Mg²⁺ compared with wild-type plants under low Mg²⁺ but not under Mg²⁺-sufficient conditions. Further analysis indicated that MGT6 was localized in the plasma membrane and played a key role in Mg²⁺ uptake by roots under Mg²⁺ limitation. We conclude that MGT6 mediates Mg²⁺ uptake in roots and is required for plant adaptation to a low-Mg²⁺ environment.

Dominant-negative function of the C-terminal fragments of NBR1 and SQSTM1 generated during enteroviral infection

Coxsackievirus infection induces an abnormal accumulation of ubiquitin aggregates that are generally believed to be noxious to the cells and have a key role in viral pathogenesis. Selective autophagy mediated by autophagy adaptor proteins, including sequestosome 1 (SQSTM1/p62) and neighbor of BRCA1 gene 1 protein (NBR1), are an important pathway for disposing of misfolded/ubiquitin conjugates. We have recently demonstrated that SQSTM1 is cleaved after coxsackievirus infection, resulting in the disruption of SQSTM1 function in selective autophagy. NBR1 is a functional homolog of SQSTM1. In this study, we propose to test whether NBR1 can compensate for the compromise of SQSTM1 after viral infection. Of interest, we found that NBR1 was also cleaved after coxsackievirus infection. This cleavage took place at two sites mediated by virus-encoded protease 2A(pro) and 3C(pro), respectively. In addition to the loss-of-function, we further investigated whether cleavage of SQSTM1/NBR1 leads to the generation of toxic gain-of-function mutants. We showed that the C-terminal fragments of SQSTM1 and NBR1 exhibited a dominant-negative effect against native SQSTM1/NBR1, probably by competing for LC3 and ubiquitin chain binding. Finally, we demonstrated a positive, mutual regulatory relationship between SQSTM1 and NBR1 during viral infection. We showed that knockdown of SQSTM1 resulted in reduced expression of NBR1, whereas overexpression of SQSTM1 led to increased level of NBR1, and vice versa, further excluding the possible compensation of NBR1 for the loss of SQSTM1. Taken together, the findings in this study suggest a novel mechanism through which coxsackievirus infection induces increased accumulation of ubiquitin conjugates and subsequent viral damage.

Identification of candidate serum biomarkers for small cell lung cancer by proteomics analysis

AIM

Detection of novel tumor biomarker will aid in diagnosis of early-stage small cell lung cancer (SCLC). The purpose of this study was to identify novel tumor biomarker in serum from patients with SCLC using a proteomics-based approach.

METHODS

Sera were analyzed before the initiation of chemotherapy. Serum proteins of SCLC patients and healthy controls were collected and separated by 2-D fluorescence differential gel electrophoresis (2-D DIGE). Positive spots were analyzed by LC-MS/MS. Different expression of identified biomarker was verified by immunohistochemical method in wax specimen from 40 patients.

RESULTS

A total of 86 proteins were shown to be differentially abundant between the serum of SCLC patients and normal subjects by 2-D DIGE. Fifteen proteins were identified by LC-MS/MS. According to the bioinformatic analysis, these proteins are mainly involved in development and carcinogenesis. Some of them have been previously demonstrated to be important prognostic factors. Differential expression of 5 proteins between the normal tissue and cancerious tissue was confirmed by immunochemistry of SCLC patients.

CONCLUSION

We have identified different serum proteins between SCLC patients and healthy controls. These proteins may be potential serum biomarkers for early detection of SCLC and play a role in the development and metastasis of SCLC.

Studying the association of microRNA-210 level with chronic hepatitis B progression

We studied the relationship between hypoxia and microRNA-210 (miR-210) levels, the miR-210 levels in patients with hepatitis B and the roles of miR-210 in liver inflammation. We used the concanavalin A (Con A) murine hepatitis model and inflammation, hypoxia and miR-210 levels were examined. In these patients, we studied serum miR-210 levels and clinical indexes related to hepatitis in 90 patients with different stages of chronic hepatitis B and 30 controls. Two functional assays of miR-210 in vitro under hypoxic condition were conducted. The animal experiments indicated that the liver and serum miR-210 levels significantly increased with liver hypoxia and inflammation. In humans, serum miR-210 levels enhanced with hepatitis severity and were related to serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB) and prothrombin activity (PTA) levels. The miR-210 functional assays showed that miR-210 elevation might be related to the decreases in HepG2.2.15 cell dehydrogenase activity and HBV replication under hypoxic conditions. Because the liver inflammation causes liver hypoxia which also results in liver and serum miR-210 level elevation, the serum miR-210 level may serve as a molecular biomarker for the severity of hepatitis and increases in liver miR-210 that we see may be a response of hepatocytes to hypoxia during hepatitis progression.

Gamma-glutamyltransferase predicts increased risk of mortality: a systematic review and meta-analysis of prospective observational studies

The aim of this study was to evaluate the association between gamma-glutamyltransferase (GGT) and mortality through a comprehensive analysis of existing evidence. PubMed, Embase, Chinese Biomedical Literature, and Science Citation Index databases were electronically searched. Studies were included if the study design was prospective and included reference and at-risk levels of GGT at baseline and mortality as a separate outcome. The quality of the studies included was assessed on the basis of Newcastle-Ottawa scale. Data from selected qualified studies were systematically reviewed, pooled, and analyzed according to the MOOSE guidelines and PRISMA statement. The results included the following: 1. 35 studies including 571,511 participants and 72,196 cases of mortality; 2. GGT, even at physiologic levels, was associated with increased all-cause mortality and cardiovascular mortality, and might also be associated with cancer-related mortality in the general population; and 3. GGT was very likely to be associated with all-cause mortality and cardiovascular mortality in patients with coronary artery disease and type 2 diabetes mellitus. Many of the studies included did not specifically exclude subjects with hepatic diseases or alcohol abuse, which may have obscured the results. Moderate heterogeneity was observed in the meta-analysis of GGT and all-cause mortality. Different compositions of cause-specific mortality might be the reason. However, subgroup analysis could only be performed on cardiovascular death because of insufficient information. GGT, even at physiologic high levels, predicted mortality, especially cardiovascular mortality and cancer mortality. The underlining mechanism and potential effects of GGT-targeted intervention on health warrant further investigation.

Phylogeny and molecular evolution analysis of PIN-FORMED 1 in angiosperm

PIN-FORMED 1 (PIN1) is an important secondary transporter and determines the direction of intercellular auxin flow. As PIN1 performs the conserved function of auxin transport, it is expected that the sequence and structure of PIN1 is conserved. Therefore, we hypothesized that PIN1 evolve under pervasive purifying selection in the protein-coding sequences in angiosperm. To test this hypothesis, we performed detailed evolutionary analyses of 67 PIN1 sequences from 35 angiosperm species. We found that the PIN1 sequences are highly conserved within their transmembrane regions, part of their hydrophilic regions. We also found that there are two or more PIN1 copies in some of these angiosperm species. PIN1 sequences from Poaceae and Brassicaceae are representative of the modern clade. We identified 12 highly conserved motifs and a significant number of family-specific sites within these motifs. One family-specific site within Motif 11 shows a different residue between monocots and dicots, and is functionally critical for the polarity of PIN1. Likewise, the function of PIN1 appears to be different between monocots and dicots since the phenotype associated with PIN1 overexpression is opposite between Arabidopsis and rice. The evolution of angiosperm PIN1 protein-coding sequences appears to have been primarily driven by purifying selection, but traces of positive selection associated with sequences from certain families also seem to be present. We verified this observation by calculating the numbers of non-synonymous and synonymous changes on each branch of a phylogenetic tree. Our results indicate that the evolution of angiosperm PIN1 sequences involve strong purifying selection. In addition, our results suggest that the conserved sequences of PIN1 derive from a combination of the family-specific site variations and conserved motifs during their unique evolutionary processes, which is critical for the functional integrity and stability of these auxin transporters, especially in new species. Finally, functional difference of PIN1 is likely to be present in angiosperm because the positive selection is occurred in one branch of Poaceae.

Alpha-1-fucosidase as a prognostic indicator for hepatocellular carcinoma following hepatectomy: a large-scale, long-term study

Background:

Preoperative alpha-L-fucosidase (AFU) has been used as a diagnostic biomarker for hepatocellular carcinoma (HCC), but its role as a prognostic predictor after partial hepatectomy has not been well defined. The study aimed to investigate the prognostic significance of preoperative serum AFU for HCC patients after hepatic resection.

Methods:

A retrospective training data set and a prospective validation data set were used to evaluate the prognosis of HCC after partial hepatectomy. A total of 669 patients with histopathologically confirmed HCC were enrolled. Univariate and multivariate analyses were used to identify the prognostic significance of preoperative serum AFU.

Results:

The retrospective training data set showed a preoperative AFU>35 u l⁻¹ should be used. The prospective validation data set showed preoperative AFU was an independent prognostic factor of overall survival (OS) (P=0.008; hazard ratio: 2.333; 95% confidence interval: 1.249–4.369). Patients with a preoperative AFU>35 u l⁻¹ had a lower recurrence-free survival rate and an OS rate than those with AFU⩽35 u l⁻¹, and they have a higher tendency to form macrovascular invasion. Furthermore, the prognostic significance of AFU>35 u l⁻¹ could also be applied to patients with alpha-fetoprotein levels of ⩽400 ng ml⁻¹.

Conclusions:

Preoperative serum AFU is a prognostic predictor of HCC.

[Zygomatic arch fracture extended to the glenoid fossa: a cause of TMJ pain]

INTRODUCTION

Fractures of the zygomatic arch extended to the glenoid fossa are rare and seldom reported.

OBSERVATION

A 26-year-old man with a slightly dislocated fracture of the zygoma associated with trismus, and localized pain in the right Temporo-Mandibular Joint (TMJ) on palpation, but without any condylar fracture. The craniofacial CT scan revealed a fracture of the zygoma extended to the glenoid fossa. The treatment was an intraoral reduction of the zygoma and screw fixation of the glenoid fossa lateral region.

DISCUSSION

The risk of delayed healing by mobilization of the bone fragments was opposed to the risk of TMJ ankylosis due to a prolonged immobilization of the joint. Osteosynthesis of the fracture was finally chosen.

Evidence that duplications of 22q11.2 protect against schizophrenia

A number of large, rare copy number variants (CNVs) are deleterious for neurodevelopmental disorders, but large, rare, protective CNVs have not been reported for such phenotypes. Here we show in a CNV analysis of 47 005 individuals, the largest CNV analysis of schizophrenia to date, that large duplications (1.5-3.0 Mb) at 22q11.2--the reciprocal of the well-known, risk-inducing deletion of this locus--are substantially less common in schizophrenia cases than in the general population (0.014% vs 0.085%, OR=0.17, P=0.00086). 22q11.2 duplications represent the first putative protective mutation for schizophrenia.

Effects of liver diseases on drug-metabolizing enzymes: implications for drug fate alterations and nano-therapeutic openings

Metabolizing and eliminating toxic chemicals in the liver are key processes in the body's defense system. Drug-metabolizing enzymes (DMEs) play central roles in such processes. The activity and expression of several key DMEs are changed in various liver diseases and thus lead to significantly altered drug disposition. This phenomenon severely affects the pharmacotherapy of clinical medications in terms of the safety and efficacy of drug responses. This review highlights liver physiological functions, altered DMEs, and altered drug disposition in liver diseases. Moreover, the implications of changes in DMEs on the fate of clinically relevant drugs are also discussed. Pregnane X receptor and constitutive androstane receptor are two liver-enriched nuclear receptors originally defined as xenobiotic sensors that affect regulation of DMEs. Altered regulation of DMEs in liver diseases contributes to the development of powerful in vitro and in vivo tools to predict drug responses and options for improved drug delivery and development. Although a number of treatment drugs are available for liver diseases, they are limited by their low drug concentration in the target site, presence of side effects, and instability in the human body. The nanoparticle drug delivery system has recently attracted research attention because of its potential to offer solutions to current obstacles that involve the use of therapeutic drugs for liver diseases. Conclusively, this review aims to improve understanding on the regulation of DMEs in liver diseases and on corresponding implications in drug disposition, including novel therapeutic medications.

Engineered stealth porous silicon nanoparticles via surface encapsulation of bovine serum albumin for prolonging blood circulation in vivo

Luminescent porous silicon nanoparticles (PSiNPs) have been widely used as drug delivery. However, fast biodegradation and short blood circulation have been major challenges for their biomedical applications. Herein, bovine serum albumin was readily encapsulated onto alkyl-terminated PSiNPs surfaces via hydrophobic interaction, which could significantly improve their water-dispersibility and long-term stability under physiological conditions. Furthermore, compared with PSiNPs alone, PSiNPs coated with bovine serum albumin remarkably reduced nonspecific cellular uptake in vitro and prolonged blood circulation in vivo.

Expression of a conifer COBRA-like gene ClCOBL1 from Chinese fir (Cunninghamia lanceolata) alters the leaf architecture in tobacco

The cell wall plays crucial roles in establishing the morphology of the plant cell, defence response to biotic and abiotic stresses, and mechanical properties of organs. The COBRA gene encodes a putative glycosylphosphatidylinositol (GPI)-anchored protein that possesses the ability to modulate cellulose deposition and orient cell expansion in plant cell. We reported here the functional characterization of ClCOBL1, a conifer COBRA-like gene from the differentiating xylem of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook). ClCOBL1 belonged to a woody plant-specific clade of the COBRA protein family with several conserved motifs. Expression pattern demonstrated that ClCOBL1 was constitutively expressed but with high level in cambium region. ClCOBL1 protein was mainly located in the cell wall and plasma membrane. Overexpression of ClCOBL1 in tobacco plants yielded altered leaf adaxial-abaxial patterning and short, swollen corolla tubes. The changed leaf architecture in the ClCOBL1 overexpressors was associated with the differential expression of leaf adaxial-abaxial identity genes. Our results indicated that ClCOBL1 was involved in the determination of leaf dorsoventrality and anisotropic expansion possibly by affecting the expression of adaxial and abaxial identity genes.

Overexpression of stearoyl-CoA desaturase 1 in bone-marrow mesenchymal stem cells increases osteogenesis

AIM

The goal of this study was to examine the relationship between stearoyl-CoA desaturase 1 (SCD1) and osteogenesis in bone marrow mesenchymal stem cells (BM-MSCs).

METHODS

SCD1 was overexpressed in BM-MSCs using lentiviral transduction. Then, osteogenesis was induced by low glucose DMEM (10% fetal bovine serum). Alkaline phosphatase (ALP) activity assays, Western blot analyses of SCD1 and osteocalcin, and stainings for ALP and alizarin red were done to assess the extent of osteogenesis in BM-MSCs.

RESULTS

ALP activity was markedly higher in the SCD1 overexpressing cells compared with cells transduced with empty vector or control (untransduced) cells at 1 and 2 weeks after osteogenic induction. By contrast, ALP activities were comparable between control cells and cells transduced with empty vector. Western blot analysis demonstrated that osteocalcin levels were higher in the SCD1 overexpressing cells, compared with cells transduced with empty vector or control cells, at 1 and 2 weeks after osteogenic induction. These findings were corroborated by stainings for ALP and alizarin red that demonstrated a more active osteogenesis in the SCD1 overexpressing cells 2 weeks after osteogenic induction.

CONCLUSION

Increased levels of SCD1 enhance osteogenesis in BM-MSCs.

Transcriptome characteristics and six alternative expressed genes positively correlated with the phase transition of annual cambial activities in Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook)

Background

The molecular mechanisms that govern cambial activity in angiosperms are well established, but little is known about these molecular mechanisms in gymnosperms. Chinese fir (Cunninghamia lanceolata (Lamb.) Hook), a diploid (2n  = 2x  = 22) gymnosperm, is one of the most important industrial and commercial timber species in China. Here, we performed transcriptome sequencing to identify the repertoire of genes expressed in cambium tissue of Chinese fir.

Methodology/Principal Findings

Based on previous studies, the four stage-specific cambial tissues of Chinese fir were defined using transmission electron microscopy (TEM). In total, 20 million sequencing reads (3.6 Gb) were obtained using Illumina sequencing from Chinese fir cambium tissue collected at active growth stage, with a mean length of 131 bp and a N50 of 90 bp. SOAPdenovo software was used to assemble 62,895 unigenes. These unigenes were further functionally annotated by comparing their sequences to public protein databases. Expression analysis revealed that the altered expression of six homologous genes (ClWOX1, ClWOX4, ClCLV1-like, ClCLV-like, ClCLE12, and ClPIN1-like) correlated positively with changes in cambial activities; moreover, these six genes might be directly involved in cambial function in Chinese fir. Further, the full-length cDNAs and DNAs for ClWOX1 and ClWOX4 were cloned and analyzed.

Conclusions

In this study, a large number of tissue/stage-specific unigene sequences were generated from the active growth stage of Chinese fir cambium. Transcriptome sequencing of Chinese fir not only provides extensive genetic resources for understanding the molecular mechanisms underlying cambial activities in Chinese fir, but also is expected to be an important foundation for future genetic studies of Chinese fir. This study indicates that ClWOX1 and ClWOX4 could be possible reverse genetic target genes for revealing the molecular mechanisms of cambial activities in Chinese fir.