High-throughput deep sequencing reveals that microRNAs play important roles in salt tolerance of euhalophyte Salicornia europaea

BACKGROUND

microRNAs (miRNAs) are implicated in plant development processes and play pivotal roles in plant adaptation to environmental stresses. Salicornia europaea, a salt mash euhalophyte, is a suitable model plant to study salt adaptation mechanisms. S. europaea is also a vegetable, forage, and oilseed that can be used for saline land reclamation and biofuel precursor production on marginal lands. Despite its importance, no miRNA has been identified from S. europaea thus far.

RESULTS

Deep sequencing was performed to investigate small RNA transcriptome of S. europaea. Two hundred and ten conserved miRNAs comprising 51 families and 31 novel miRNAs (including seven miRNA star sequences) belonging to 30 families were identified. About half (13 out of 31) of the novel miRNAs were only detected in salt-treated samples. The expression of 43 conserved and 13 novel miRNAs significantly changed in response to salinity. In addition, 53 conserved and 13 novel miRNAs were differentially expressed between the shoots and roots. Furthermore, 306 and 195 S. europaea unigenes were predicted to be targets of 41 conserved and 29 novel miRNA families, respectively. These targets encoded a wide range of proteins, and genes involved in transcription regulation constituted the largest category. Four of these genes encoding laccase, F-box family protein, SAC3/GANP family protein, and NADPH cytochrome P-450 reductase were validated using 5'-RACE.

CONCLUSIONS

Our results indicate that specific miRNAs are tightly regulated by salinity in the shoots and/or roots of S. europaea, which may play important roles in salt tolerance of this euhalophyte. The S. europaea salt-responsive miRNAs and miRNAs that target transcription factors, nucleotide binding site-leucine-rich repeat proteins and enzymes involved in lignin biosynthesis as well as carbon and nitrogen metabolism may be applied in genetic engineering of crops with high stress tolerance, and genetic modification of biofuel crops with high biomass and regulatable lignin biosynthesis.

Genetic variants of PLA2G6 are associated with Type 2 diabetes mellitus and triglyceride levels in a Chinese population

AIM

To test the association of PLA2G6 variants with Type 2 diabetes and clinical characteristics in large Chinese population-based samples.

METHODS

A total of 6822 people were recruited. In the first stage, 15 single nucleotide polymorphisms within the PLA2G6 region were selected and genotyped in 3700 Chinese Han people. In the second stage, the single nucleotide polymorphisms that showed a significant association were genotyped in an additional 3122 samples for replication. Genotype-phenotype association studies and meta-analyses were performed after combining data from the two stages.

RESULTS

In the first stage, we detected rs132984 and rs2284060 as significantly associated with Type 2 diabetes with odds ratios of 1.247 (95% CI 1.074-1.449, P = 0.004, empirical P = 0.047) and 1.173 (95% CI 1.059-1.299, P = 0.002, empirical P = 0.029), respectively. In the second stage, a similar effect of rs132984 on Type 2 diabetes was observed (odds ratio 1.280, 95% CI 1.094-1.497, P = 0.002). The meta-analysis showed a significant effect of the two single nucleotide polymorphisms on Type 2 diabetes (odds ratio 1.254, 95% CI 1.104-1.451, P = 4.85 × 10⁻⁵ for rs132984; odds ratio 1.120, 95% CI 1.046-1.195, P = 0.003 for rs2284060). Moreover, genotype-phenotype association analysis showed that rs132984 was associated with triglyceride levels (P = 0.022, empirical P = 0.044) and area under the curve for glucose (P = 0.015, empirical P = 0.030).

CONCLUSIONS

Our data imply that common single nucleotide polymorphisms within the PLA2G6 region are associated with Type 2 diabetes and triglyceride levels in the Chinese population.

Overexpression of SeNHX1 improves both salt tolerance and disease resistance in tobacco

Recently, we found NHX1, the gene encoding a Na(+)/H(+) exchanger, participated in plant disease defense. Although NHX1 has been confirmed to be involved in plant salt tolerance, whether the NHX1 transgenic plants exhibit both salt tolerance and disease resistance has not been investigated. The T1 progenies of Nicotiana tabacum L. lines expressing SeNHX1 (from Salicornia europaea) were generated for the present study. Compared with PBI-type control plants, SeNHX1 transgenic tobaccos exhibited more biomass, longer root length, and higher K(+)/Na(+) ratio at post germination or seedling stage under NaCl treatment, indicating enhanced salt tolerance. The vacuolar H(+) efflux in SeNHX1 transgenic tobacco was increased after treatment of NaCl with different concentration. Meanwhile, the SeNHX1 transgenic tobaccos showed smaller wilted spot area, less H2O2 accumulation in leaves after infection of Phytophthora parasitica var. nicotianae. Further investigation demonstrated a larger NAD(P)(H) pool in SeNHX1 transgenic tobacco. These evidences revealed that overexpression of SeNHX1 intensified the compartmentation of Na(+) into vacuole under salt stress and improved the ability of eliminating ROS after pathogen attack, which then enhanced salt tolerance and disease resistance simultaneously in tobacco. Our findings indicate NHX1 has potential value in creating crops with both improved salt tolerance and disease resistance.

Topical axitinib suppresses angiogenesis pathways induced by pulsed dye laser

BACKGROUND

The recurrence of port-wine stain (PWS) blood vessels by pulsed dye laser (PDL)-induced angiogenesis is a critical barrier that must be overcome to achieve a better therapeutic outcome.

OBJECTIVES

To determine whether PDL-induced angiogenesis can be suppressed by topical axitinib.

METHODS

The mRNA expression profiles of 86 angiogenic genes and phosphorylation levels of extracellular signal regulated kinases (ERKs), phosphorylated protein kinase B (AKT) and ribosomal protein S6 kinase (p70S6K) in rodent skin were examined with or without topical axitinib administration after PDL exposure.

RESULTS

The PDL-induced increased transcriptional levels of angiogenic genes peaked at days 3-7 post-PDL exposure. Topical application of 0·5% axitinib effectively suppressed the PDL-induced increase in mRNA levels of the examined angiogenic genes and activation of AKT, P70S6K and ERK from days 1 to 7 post-PDL exposure. After topical administration, axitinib penetrated into rodent skin to an approximate depth of 929·5 μm.

CONCLUSIONS

Topical application of 0·5% axitinib can systematically suppress the PDL-induced early stages of angiogenesis via inhibition of the AKT/mammalian target of rapamycin/p70S6K and Src homology 2 domain containing transforming protein-1/mitogen-activated protein kinase kinase/ERK pathway cascades.

Vitamin D deficiency increases the risk of retinopathy in Chinese patients with type 2 diabetes

AIMS

To investigate the relationship between vitamin D deficiency and diabetic retinopathy.

METHODS

In total, 1520 patients with Type 2 diabetes were recruited and divided into three groups according to their fundus oculi results: no diabetic retinopathy (n = 625, 41.12%); non-sight-threatening diabetic retinopathy (n = 562, 36.97%); and sight-threatening diabetic retinopathy (n = 333, 21.91%). Vitamin D deficiency was defined as a serum circulating 25-hydroxyvitamin D level < 20 ng/ml. Clinical characteristics and biochemical parameters were detected and compared.

RESULTS

The patients with sight-threatening diabetic retinopathy had significantly lower serum 25-hydroxyvitamin D concentrations and higher prevalence of vitamin D deficiency than other two groups (all P < 0.05). In addition, there was a downward trend in average 25-hydroxyvitamin D level with the increased stages of diabetic retinopathy (P < 0.01). The prevalence of diabetic retinopathy and sight-threatening diabetic retinopathy in patients with vitamin D deficiency was also higher than in those without vitamin D deficiency (both P < 0.01). After adjusting for all potential confounders, vitamin D deficiency was still associated with increased risk of diabetic retinopathy (odds ratio 1.93) and sight-threatening diabetic retinopathy (odds ratio 2.42) (both P < 0.01). Logistical regression analysis further revealed that vitamin D deficiency was an independent risk factor for diabetic retinopathy (β = 0.66) and sight-threatening diabetic retinopathy (β = 0.93) (both P < 0.01). ROC analysis indicated that a serum 25-hydroxyvitamin D level < 15.57 ng/ml suggested the occurrence of sight-threatening diabetic retinopathy (odds ratio 2.38, P < 0.01).

CONCLUSIONS

Vitamin D deficiency is an independent risk factor for diabetic retinopathy and sight-threatening diabetic retinopathy. The prevalence of sight-threatening diabetic retinopathy doubles when the serum 25-hydroxyvitamin D level is < 15.57 ng/ml.

Systemic delivery of siRNA in pumpkin by a plant PHLOEM SMALL RNA-BINDING PROTEIN 1-ribonucleoprotein complex

In plants, the vascular system, specifically the phloem, functions in delivery of small RNA (sRNA) to exert epigenetic control over developmental and defense-related processes. Although the importance of systemic sRNA delivery has been established, information is currently lacking concerning the nature of the protein machinery involved in this process. Here, we show that a PHLOEM SMALL-RNA BINDING PROTEIN 1 (PSRP1) serves as the basis for formation of an sRNA ribonucleoprotein complex (sRNPC) that delivers sRNA (primarily 24 nt) to sink organs. Assembly of this complex is facilitated through PSRP1 phosphorylation by a phloem-localized protein kinase, PSRPK1. During long-distance transport, PSRP1-sRNPC is stable against phloem phosphatase activity. Within target tissues, phosphatase activity results in disassembly of PSRP1-sRNPC, a process that is probably required for unloading cargo sRNA into surrounding cells. These findings provide an insight into the mechanism involved in delivery of sRNA associated with systemic gene silencing in plants.

Na⁺/H⁺ exchanger 1 participates in tobacco disease defence against Phytophthora parasitica var. nicotianae by affecting vacuolar pH and priming the antioxidative system

Despite the importance of NHX1 (Na(+)/H(+) exchanger 1) in plant salt tolerance, little is known about its other functions. In this study, intriguingly, it was found that NHX1 participated in plant disease defence against Phytophthora parasitica var. nicotianae (Ppn) in Nicotiana benthamiana. NbNHX1 was originally isolated from N. benthamiana, and characterized. The subcellular localization of NbNHX1 with its C-terminus fused with green fluorescent protein indicated that NbNHX1 localized primarily to the tonoplast. Tobacco rattle virus-induced NbNHX1 silencing led to reduced H(+) efflux from the vacuole to cytoplasts, and decreased Ppn resistance in N. benthamiana. After attack by Ppn, NbNHX1-silenced plants exhibited impaired ability to scavenge reactive oxidative species (ROS) induced by the pathogen. Pea early browning virus-mediated ectopic expression of SeNHX1 (from Salicornia europaea) or AtNHX1 (from Arabidopsis thaliana) both conferred enhanced Ppn resistance to N. benthamiana, with a lower H2O2 concentration after Ppn inoculation. Further investigation of the role of NHX1 demonstrated that transient overexpression of NbNHX1 improved the vacuolar pH and cellular ROS level in N. benthamiana, which was coupled with an enlarged NAD(P) (H) pool and higher expression of ROS-responsive genes. In contrast, NbNHX1 silencing led to a lower pH in the vacuole and a lower cellular ROS level in N. benthamiana, which was coupled with a decreased NAD(P) (H) pool and decreased expression of ROS-responsive genes. These results suggest that NHX1 is involved in plant disease defence; and regulation of vacuolar pH by NHX1, affecting the cellular oxidation state, primes the antioxidative system which is associated with Ppn resistance in tobacco.

Association of PAX4 genetic variants with oral antidiabetic drugs efficacy in Chinese type 2 diabetes patients

The aim of this study was to investigate the association of PAX4 variants with therapeutic effect of oral antidiabetic drugs in Chinese type 2 diabtes mellitus (T2DM) patients. A total of 209 newly diagnosed T2DM patients were randomly assigned to treatment with repaglinide or rosiglitazone for 48 weeks, and the therapeutic effects were compared. In the rosiglitazone cohort, rs6467136 GA+AA carriers showed greater decrease in 2-h glucose levels (P=0.0063) and higher cumulative attainment rates of target 2-h glucose levels (Plog rank=0.0093) than GG homozygotes. In the subgroup with defective β-cell function, rs6467136 GA+AA carriers exhibited greater decrements of 2-h glucose level and improvement of homeostasis model assessment of insulin resistance (P=0.0143). Moreover, GA+AA carriers were more likely to attain the target fasting and 2-h glucose level (Plog rank=0.0091 and 0.007, respectively). However, these single-nucleotide polymorphisms showed no effect on repaglinide efficacy. In conclusion, PAX4 variant rs6467136 was associated with the therapeutic effect of rosiglitazone in Chinese T2DM patients.

Clinical study of exercise on improvement of β-cell function and insulin resistance in non-diabetic young offsprings of diabetic patients

BACKGROUND

Previous studies have shown that exercise could improve β-cell function in humans or animal models of type 2 diabetes. However, whether it can prevent the progression of pre-diabetes to diabetes remains unclear.

AIM

To study the effects of exercise on glycolipid metabolism, β-cell function, and insulin resistance in the non-diabetic young offsprings of diabetic patients.

METHODS

One hundred and eighty-two normal glucose tolerance young offsprings of type 2 diabetic parents were enrolled. Individuals with fasting insulin ≥ 12.0 mU/L were assigned to hyperinsulinemia group (n = 72) and those with fasting insulin <12.0 mU/L were assigned to normal group (n = 110). The subjects in hyperinsulinemia group received 12-week exercise intervention. A 75-g oral glucose tolerance test and insulin release test were conducted before and after intervention. The area under curve of glucose (AUCglu), area under curve of insulin (AUCINS), HOMA insulin resistance index (HOMA-IR), HOMA β-cell function (HOMA-β), and early insulin secretion index (ΔI 30/ΔG 30) were calculated. Body composition was measured by dual energy X-ray absorptiometry.

RESULTS

At baseline, AUCINS and HOMA-β in hyperinsulinemia group were significantly higher compared with the normal group (P < 0.05). After the 12-week exercise intervention, no significant changes in blood pressure, body mass index, blood glucose, serum lipids, and percentage of body fat were found in hyperinsulinemia group; however, AUCINS, HOMA-β, HOMA-IR (P < 0.05) and ΔI 30/ΔG 30 (P < 0.01) were significantly decreased.

CONCLUSIONS

Exercise is effective for preventing pre-diabetic insulin resistance and β-cell dysfunction in non-diabetic young offsprings of diabetic patients.

Transcriptome analysis of Salicornia europaea under saline conditions revealed the adaptive primary metabolic pathways as early events to facilitate salt adaptation

BACKGROUND

Halophytes such as Salicornia europaea have evolved to exhibit unique mechanisms controlled by complex networks and regulated by numerous genes and interactions to adapt to habitats with high salinity. However, these mechanisms remain unknown.

METHODS

To investigate the mechanism by which halophytes tolerate salt based on changes in the whole transcriptome, we performed transcriptome sequencing and functional annotation by database search. Using the unigene database, we conducted digital gene expression analysis of S. europaea at various time points after these materials were treated with NaCl. We also quantified ion uptakes. Gene functional enrichment analysis was performed to determine the important pathways involved in this process.

RESULTS

A total of 57,151 unigenes with lengths of >300 bp were assembled, in which 57.5% of these unigenes were functionally annotated. Differentially expressed genes indicated that cell wall metabolism and lignin biosynthetic pathways were significantly enriched in S. europaea to promote the development of the xylem under saline conditions. This result is consistent with the increase in sodium uptake as ions pass through the xylem. Given that PSII efficiency remained unaltered, salt treatment activated the expression of electron transfer-related genes encoded by the chloroplast chromosome. Chlorophyll biosynthesis was also inhibited, indicating the energy-efficient state of the electron transfer system of S. europaea.

CONCLUSIONS

The key function of adjusting important primary metabolic pathways in salt adaption was identified by analyzing the changes in the transcriptome of S. europaea. These pathways could involve unique salt tolerance mechanisms in halophytes. This study also provided information as the basis of future investigations on salt response genes in S. europaea. Ample gene resources were also provided to improve the genes responsible for the salt tolerance ability of crops.

Asymmetric dimethylarginine attenuates serum starvation-induced apoptosis via suppression of the Fas (APO-1/CD95)/JNK (SAPK) pathway

Asymmetric dimethylarginine (ADMA) is synthesized by protein arginine methyltransferases during methylation of protein arginine residues and released into blood upon proteolysis. Higher concentrations of ADMA in blood have been observed in patients with metabolic diseases and certain cancers. However, the role of ADMA in colon cancer has not been well investigated. ADMA serum levels in human patients diagnosed with colon cancer were found to be higher than those present in healthy subjects. ADMA treatment of LoVo cells, a human colon adenocarcinoma cell line, attenuated serum starvation-induced apoptosis and suppressed the activation of the Fas (APO-1/CD95)/JNK (SAPK) (c-Jun N terminal protein kinase/stress-activated protein kinase)pathway. ADMA also suppressed the activation of JNK triggered by death receptor ligand anti-Fas mAb and exogenous C₂-ceramide. Moreover, we demonstrated that ADMA pretreatment protected LoVo cells from doxorubicin hydrochloride-induced cell death and activation of the Fas/JNK pathway. In summary, our results suggest that the elevated ADMA in colon cancer patients may contribute to the blocking of apoptosis of cancer cells in response to stress and chemotherapy.

Association between KCNQ1 genetic variants and QT interval in a Chinese population

AIM

There is a close link between electrocardiographic ventricular repolarization QT parameters and Type 2 diabetes. The aim of the present study was to assess the effects of QT-related and diabetes-related variants in KCNQ1 on QT interval in a Chinese population.

METHODS

We recruited 2415 patients with Type 2 diabetes and 1163 subjects with normal glucose regulation in the present study. QT interval was obtained and the heart rate-corrected QT interval (QTc) was calculated using Bazett's formula. Four single nucleotide polymorphisms in KCNQ1 were selected (rs12296050, rs12576239, rs2237892 and rs2237895) and genotyped.

RESULTS

In participants with normal glucose regulation, the minor allele T of rs12296050 was associated with a 3.46-ms QTc prolongation under an additive model (P = 0.0109, empirical P = 0.0498). In patients with Type 2 diabetes, we did not find any association for the single nucleotide polymorphisms.

CONCLUSIONS

Our findings indicate that KCNQ1 is associated with QT interval in a Chinese population with normal glucose regulation.

Cometabolism of microbes and host: implications for drug metabolism and drug-induced toxicity

The recognition of the gut microbial-mammalian metabolic axis and its implications in human metabolic disease opens a new window to understanding the contribution of the gut microbiome to drug metabolism and drug-induced toxicity. The integrative omics approaches, including pharmacometabonomics and metagenomics, have demonstrated great promise for characterizing xenobiotic interventions that are associated with wide variation in efficacy or toxicity in humans, as well as for predicting individual response and susceptibility to toxicity.

S100A4 silencing suppresses proliferation, angiogenesis and invasion of thyroid cancer cells through downregulation of MMP-9 and VEGF

BACKGROUND AND AIM

It is well documented that S100A4 is upregulated in many cancers and plays a pivotal role in tumor proliferation, invasion, metastasis and angiogenesis. However, the precise role and mechanism S100A4 exerts in the thyroid cancer have not been fully elucidated to date. In the present study, we investigated the effect of S100A4 on proliferation, invasion, metastasis and angiogenesis in thyroid cancer cells.

MATERIALS AND METHODS

A plasmid construct was made that expressed full long S100A4 cDNA. The construct was stably transfected into BCPAP and ML-1 thyroid cancer cells (BCPAP/ S100A4 cDNA, ML-1/S100A4 cDNA). S100A4 siRNA was transiently transfected into the DRO cells (DRO/S100A4 siRNA). MMP-9 siRNA or VEGF siRNA was transiently transfected into the BCPAP/ S100A4 cDNA, ML-1/S100A4 cDNA cells (BCPAP/ S100A4 cDNA/VEGF siRNA, ML-1/S100A4 cDNA/ MMP-9 siRNA).

RESULTS

We found that the down-regulation of S100A4 by small interfering RNA decreased cell invasion, metastasis, and angiogenesis by using chicken chorioallantoic membrane (CAM), whereas S100A4 overexpression by cDNA transfection led to increased tumor cell invasion, metastasis, and angiogenesis. Consistent with these results, we found that the down-regulation of S100A4 reduced VEGF and MMP-9 expression. Furthermore, Knockdown of MMP-9 by MMP-9 siRNA inhibited cell invasion and metastasis in the BCPAP/S100A4 cDNA, ML-1/S100A4 cDNA cells. Knockdown of VEGF by VEGF siRNA inhibited cell angiogenesis in the BCPAP/ S100A4 cDNA, ML-1/S100A4 cDNA cells.We also found that downregulation of S100A4 by small interfering RNA resulted in enhanced cell growth inhibition and apoptosis, and vice versa. Our data suggest S100A4 could be an effective approach for the regulation of proliferation, invasion and angiogenesis. Downregulation of S100A4 could inhibit angiogenesis, proliferation and invasion by regulating the expression of MMP-9 and VEGF.

CONCLUSIONS

Our results provide evidence that the downregulation of S100A4 using RNAi technology may provide an effective tool for thyroid cancer therapy.

Genome-wide association study in a Chinese population identifies a susceptibility locus for type 2 diabetes at 7q32 near PAX4

AIMS/HYPOTHESIS

Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians.

METHODS

We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations.

RESULTS

We identified CDKN2A/B and four novel type 2 diabetes association signals with p < 1 × 10(-5) from the meta-analysis. Thirteen variants within these four loci were followed up in two independent Chinese cohorts, and rs10229583 at 7q32 was found to be associated with type 2 diabetes in a combined analysis of 11,067 cases and 7,929 controls (p meta = 2.6 × 10(-8); OR [95% CI] 1.18 [1.11, 1.25]). In silico replication revealed consistent associations across multiethnic groups, including five East Asian populations (p meta = 2.3 × 10(-10)) and a population of European descent (p = 8.6 × 10(-3)). The rs10229583 risk variant was associated with elevated fasting plasma glucose, impaired beta cell function in controls, and an earlier age at diagnosis for the cases. The novel variant lies within an islet-selective cluster of open regulatory elements. There was significant heterogeneity of effect between Han Chinese and individuals of European descent, Malaysians and Indians.

CONCLUSIONS/INTERPRETATION

Our study identifies rs10229583 near PAX4 as a novel locus for type 2 diabetes in Chinese and other populations and provides new insights into the pathogenesis of type 2 diabetes.

Glucose regulates secretion of exogenously expressed insulin from HepG2 cells in vitro and in a mouse model of diabetes mellitus in vivo

Glucose-controlled insulin secretion is a key component of its regulation. Here, we examined whether liver cell secretion of insulin derived from an engineered construct can be regulated by glucose. Adenovirus constructs were designed to express proinsulin or mature insulin containing the conditional binding domain (CBD). This motif binds GRP78 (HSPA5), an endoplasmic reticulum (ER) protein that enables the chimeric hormone to enter into and stay within the ER until glucose regulates its release from the organelle. Infected HepG2 cells expressed proinsulin mRNA and the protein containing the CBD. Immunocytochemistry studies suggested that GRP78 and proinsulin appeared together in the ER of the cell. The amount of hormone released from infected cells varied directly with the ambient concentration of glucose in the media. Glucose-regulated release of the hormone from infected cells was rapid and sustained. Removal of glucose from the cells decreased release of the hormone. In streptozotocin-induced diabetic mice, when infected with adenovirus expressing mature insulin, glucose levels declined. Our data show that glucose regulates release of exogenously expressed insulin from the ER of liver cells. This approach may be useful in devising new ways to treat diabetes mellitus.

Prevalence of cardiovascular disease and risk factors in the Chinese population with impaired glucose regulation: the 2007-2008 China national diabetes and metabolic disorders study

Cardiovascular disease (CVD) is one of the most common chronic diseases in China. This aim of this study is to determine the prevalence of CVDs and risk factors in Chinese impaired glucose regulation subjects.We used a multistage, stratified sampling method to select subjects from the general Chinese population aged 20 years and older. Subjects underwent an oral glucose tolerance test to identify normal glucose tolerance (NGT) and impaired glucose regulation including isolated impaired fasting glucose (i-IFG), impaired glucose tolerance (i-IGT), and combined IFG/IGT and diabetic mellitus (DM). A logistic regression analysis was performed to examine the association between glucose abnormalities and CVD events.We identified that 34 293 subjects had NGT, 1 469 i-IFG, 4 571 i-IGT, 957 IFG/IGT and 4 949 DM. The age-sex standardized prevalence rate of cardiovascular disease was 1.06% (95% CI 0.87-1.28), 1.79% (95% CI 1.37-2.33) and 3.83% (95% CI 2.79-5.24) in NGT, impaired glucose regulation and DM, respectively. Among impaired glucose subjects, prevalence of defined CVD risk factors (smoking, overweight, obesity, hypertension and dyslipidemia) was 29.52% (95% CI: 27.8-31.21), 36.25% (95% CI: 34.29-38.26), 10.05% (95% CI: 8.86-11.37), 36.43% (95% CI: 34.53-38.36) and 69.96% (95% CI: 67.87-71.98), respectively. Compared to 1 risk factor, the odds ratios (ORs) of CVDs with 2, 3 or 4 risk factors were 1.94 (95% CI: 0.74-5.09), 2.76 (95% CI: 1.06-7.21) and 5.84 (95% CI: 1.68-20.26), respectively. Additionally, compared to i-IFGs, ORs of CVDs with i-IGT and IFG/IGT were 2.88 (95%CI 1.36-6.01) and 2.12 (95% CI 0.83-5.44), respectively.The prevalence of cardiovascular risk factors was high in the Chinese impaired glucose regulation population. The postprandial hyperglycemia is more associated with CVD than isolated fasting hyperglycemia.

Genetic variants of LPIN1 indicate an association with Type 2 diabetes mellitus in a Chinese population

AIMS

Metabolic disorders are independent risk factors for the development of Type 2 diabetes. The aim of the study is to test the association of LPIN1 variants with Type 2 diabetes and clinical characteristics in large samples of the Chinese population.

METHODS

In the first stage, 15 single nucleotide polymorphisms within the LPIN1 region were selected and genotyped in 3700 Chinese Han participants. In the second stage, the single nucleotide polymorphisms showing significant association or trends towards association were genotyped in an additional 3122 samples for replication. Meta-analyses and genotype-phenotype association studies were performed after combining the data from the two stages.

RESULTS

In the first stage, we detected that rs16857876 was significantly associated with Type 2 diabetes with an odds ratio of 0.806 (95% CI 0.677-0.958, P = 0.015), while rs11695610 showed a trend with Type 2 diabetes (odds ratio 0.846, 95% CI 0.709-1.009, P = 0.062). In the second stage, a similar effect of rs11695610 on Type 2 diabetes was observed (odds ratio 0.849, 95% CI 0.700-1.030, P = 0.096). The meta-analyses combining the information from the two stages showed a significant effect of rs11695610 on Type 2 diabetes with an odds ratio of 0.847 (95% CI 0.744-0.965, P = 0.012). Finally, the phenotype-genotype association analyses showed that rs11695610 was associated with 2-h plasma glucose (P = 0.040) and triglyceride levels (P = 0.034).

CONCLUSIONS

Our data implied that common single nucleotide polymorphisms within the LPIN1 region were associated with Type 2 diabetes and metabolic traits in the Chinese population.

Potential metabolite markers of schizophrenia

Schizophrenia is a severe mental disorder that affects 0.5-1% of the population worldwide. Current diagnostic methods are based on psychiatric interviews, which are subjective in nature. The lack of disease biomarkers to support objective laboratory tests has been a long-standing bottleneck in the clinical diagnosis and evaluation of schizophrenia. Here we report a global metabolic profiling study involving 112 schizophrenic patients and 110 healthy subjects, who were divided into a training set and a test set, designed to identify metabolite markers. A panel of serum markers consisting of glycerate, eicosenoic acid, β-hydroxybutyrate, pyruvate and cystine was identified as an effective diagnostic tool, achieving an area under the receiver operating characteristic curve (AUC) of 0.945 in the training samples (62 patients and 62 controls) and 0.895 in the test samples (50 patients and 48 controls). Furthermore, a composite panel by the addition of urine β-hydroxybutyrate to the serum panel achieved a more satisfactory accuracy, which reached an AUC of 1 in both the training set and the test set. Multiple fatty acids and ketone bodies were found significantly (P<0.01) elevated in both the serum and urine of patients, suggesting an upregulated fatty acid catabolism, presumably resulting from an insufficiency of glucose supply in the brains of schizophrenia patients.

Functional analyses of the mutation nt-128 T→G in the hepatocyte nuclear factor-1α promoter region in Chinese diabetes pedigrees

AIMS

Hepatocyte nuclear factor-1α (HNF-1α) regulates the expression of genes encoding proteins involved in glucose metabolism and insulin secretion. Mutations in the HNF-1α gene cause maturity-onset diabetes of the young Type 3. However, the mechanism leading to this disease has not been completely ascertained. Previously, we found a novel mutation in the regulatory element of the human HNF-1α gene in two Chinese diabetes pedigrees. The nucleotide at position -128 T was substituted by G (nt-128 T→G). In this study, we analysed the functional defect of nt-128 T→G in HNF-1α transcription activity.

METHODS

Luciferase reporter gene assays were carried out to examine the functional characteristics of this mutant. Electrophoretic mobility shift assays and chromatin immunoprecipitation were performed to confirm the binding of nuclear proteins to oligonucleotides.

RESULTS

The variant construct (nt-128 T→G) had a 1.65-fold increase in promoter activity compared with that of the wild-type construct in HepG2 cells and a 1.33-fold increase in MIN6 cells, respectively. The variant resided at a FOXA/HNF-3 binding site identified by a series of competitive electrophoretic mobility shift assays and antibody supershift analyses. The assays showed a differential binding affinity in the wild-type and the nt-128 T→G mutant fragments by FOXA/HNF-3. Chromatin immunoprecipitation indicated that FOXA/HNF-3 bound to this region in vivo. One nucleotide substitution in the FOXA/HNF-3 site in the human HNF-1α regulatory element caused an increase of HNF-1α transcriptional activity.

CONCLUSIONS

Our data suggested that this substitution in the promoter region affects DNA-protein interaction and HNF-1α gene transcription. The mutant may contribute to the development of diabetes in these two nt-128 T→G pedigrees of Chinese.