Environmental drivers of increased ecosystem respiration in a warming tundra.

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5-7. This hampers the accuracy of global land carbon-climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9-2.0 °C] in air and 0.4 °C [CI 0.2-0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22-38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

Subclinical thyroid dysfunction, bone mineral density, and osteoporosis in a middle-aged Korean population.

Thyroid dysfunction is associated with the loss of bone density (osteoporosis). However, the connection between subclinical thyroid dysfunction and osteoporosis remains controversial. This study found no apparent association between subclinical hypothyroidism or subclinical hyperthyroidism and bone mineral density (BMD) in the lumbar spine and femur. INTRODUCTION: The present study examined the relationship between subclinical thyroid dysfunction and BMD in healthy middle-aged adults. METHODS: A total of 25,510 healthy Koreans with normal free thyroxine levels were enrolled from January 2011 to December 2016, and 91% of subjects visited only once. The average age of the 15,761 women was 45, and the average age of the 9749 men was 48. Levels of thyroid-stimulating hormone (TSH) and BMD were recorded in all subjects. BMD was measured using dual-energy X-ray absorptiometry. RESULTS: No apparent association was found between subclinical thyroid dysfunction and BMD in the lumbar spine, femur-neck, and proximal femur sites compared with a euthyroid group. Age, body mass index (BMI), and postmenopausal status affected BMD in women, and only BMI affected BMD in men. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis (odds ratio 0.657, 95% confidence interval 0.464-0.930) in 4710 postmenopausal women. CONCLUSIONS: No apparent association was found between subclinical hypothyroidism or subclinical hyperthyroidism defined on single TSH measurement and BMD at the lumbar spine and femur in a large cohort of middle-aged men and women. Subclinical hypothyroidism was independently associated with a lower risk of osteoporosis in postmenopausal women.

Correction: ESRP1 is overexpressed in ovarian cancer and promotes switching from mesenchymal to epithelial phenotype in ovarian cancer cells.

Since publication of the original article, the authors have noticed that there were errors in the labelling of Figures 6D and 6E. The correct figure and its legend are reproduced here. The authors wish to apologise for any inconvenience caused.

Updating genome annotation for the microbial cell factory Aspergillus niger using gene co-expression networks.

A significant challenge in our understanding of biological systems is the high number of genes with unknown function in many genomes. The fungal genus Aspergillus contains important pathogens of humans, model organisms, and microbial cell factories. Aspergillus niger is used to produce organic acids, proteins, and is a promising source of new bioactive secondary metabolites. Out of the 14,165 open reading frames predicted in the A. niger genome only 2% have been experimentally verified and over 6,000 are hypothetical. Here, we show that gene co-expression network analysis can be used to overcome this limitation. A meta-analysis of 155 transcriptomics experiments generated co-expression networks for 9,579 genes (∼65%) of the A. niger genome. By populating this dataset with over 1,200 gene functional experiments from the genus Aspergillus and performing gene ontology enrichment, we could infer biological processes for 9,263 of A. niger genes, including 2,970 hypothetical genes. Experimental validation of selected co-expression sub-networks uncovered four transcription factors involved in secondary metabolite synthesis, which were used to activate production of multiple natural products. This study constitutes a significant step towards systems-level understanding of A. niger, and the datasets can be used to fuel discoveries of model systems, fungal pathogens, and biotechnology.

ESRP1 is overexpressed in ovarian cancer and promotes switching from mesenchymal to epithelial phenotype in ovarian cancer cells.

This corrects the article DOI: 10.1038/oncsis.2017.87.

ESRP1 is overexpressed in ovarian cancer and promotes switching from mesenchymal to epithelial phenotype in ovarian cancer cells.

Epithelial splicing regulatory protein 1 (ESRP1) and 2 (ESRP2), epithelial cell-specific regulators of alternative splicing, are downregulated during the epithelial-mesenchymal transition (EMT). These factors have roles in tumor progression and metastasis in some cancers; however, their expression and function in ovarian cancer (OC) remain unclear. We found that ESRP1 and ESRP2 mRNAs were expressed at higher levels in OC cells than in immortalized ovarian surface epithelial (IOSE) cells, and confirmed their overexpression in OC tissues at the protein level. The Cancer Genome Atlas (TCGA) data analysis revealed frequent gene amplification of ESRP1 in OC tissues; however, we detected no significant correlation between ESRP1 gene copy number and gene expression in OC cells. Importantly, expression of ESRP1 and ESRP2 was inversely correlated with DNA methylation in OC cells, and ESRP2 overexpression in OC tissues was significantly associated with DNA hypomethylation. Notably, survival analysis using TCGA data from 541 OC tissues revealed that high ESRP1 expression was significantly associated with shorter 5-year survival of patients. Ectopic ESRP1 expression in mesenchymal OC cells promoted cell proliferation but suppressed cell migration. Furthermore, we found that ESRP1 drives a switch from mesenchymal to epithelial phenotype characterized by reduced cell migration in association with induction of epithelial cell-specific variant of CD44 and ENAH. Taken together, our findings suggest that an epigenetic mechanism is involved in ESRP1 overexpression, and that ESRP1 has a role in OC progression.

The effect of PPARγ agonist on SGLT2 and glucagon expressions in alpha cells under hyperglycemia.

BACKGROUND: Although sodium glucose cotransporter 2 (SGLT2) inhibitors have many beneficial effects for type 2 diabetes, including decreased cardiovascular death, recent reports that they increased glucagon through SGLT2 inhibition raised some concern. Troglitazone, Peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, was reported to increase SGLT2 in renal proximal tubule cells, but its role on pancreatic alpha cells have not been reported. We investigated the effect of troglitazone on SGLT2 expression in alpha cells and subsequent glucagon regulation in hyperglycemia. METHODS: An Alpha TC1-6 cell line was cultured in control (5 mM) or hyperglycemia (HG, 15 mM) for 72 h. We applied troglitazone with or without PPARγ antagonist (GW9662 10 µM). To investigate the involvement of PI3K/Akt pathway, we applied troglitazone with or without Wortmanin. We measured sodium glucose transporter 2 (SGLT2) and glucagon (GCG) mRNA and protein expression. PPAR gamma, PI3K and Akt protein were also measured. RESULTS: Exposure of alpha TC cells to HG for 72 h increased glucagon mRNA and protein expression. HG decreased SGLT2 mRNA and protein expression. Troglitazone significantly reversed HG-induced reduction of SGLT2 expression and increase of glucagon secretion. PPARγ antagonist (GW9662 10 µM) decreased the expression of SGLT2 and increased glucagon as HG did. Hyperglycemia increased PI3K and pAkt expression in alpha cells. Wortmanin (PI3K inhibitor, 1 µM) reversed HG-induced SGLT2 decrease and glucagon increase. Troglitazone treatment decreased PI3K and pAkt expression in HG. CONCLUSION: In conclusion, PPARγ agonist, troglitazone improved glucose transport SGLT2 dysfunction and subsequent glucagon dysregulation in alpha cell under hyperglycemia. Those effects were through the involvement of PI3K/pAkt signaling pathway. This study may add one more reason for the ideal combination of PPARγ agonist and SGLT2 inhibitor in clinical practice.

Insulin resistance increases loss of antibody to hepatitis B surface antigen in nondiabetic healthy adults.

The aim of this study was to evaluate the impact of insulin resistance on the persistence of a protective level of anti-HBs (hepatitis B surface antigen) in a nondiabetic general population. A cohort study was designed comprising of 38 473 Korean men and women with anti-HBs at concentrations ≥10 mIU/mL, who underwent a health examination. Insulin resistance was assessed with a homoeostasis model assessment of insulin resistance (HOMA-IR). A decline in anti-HBs to <10 mIU/L during the follow-up was considered to be a loss of protective anti-HBs. Cox-proportional hazard models were used to estimate the adjusted hazard ratios and 95% confidence intervals for anti-HBs loss across quintiles of HOMA-IR and insulin. We identified 20 826 incidents of loss of anti-HBs antibody during 180 522 person-years of follow-up (incident rate 11.5 per 100 person-years). Increasing HOMA-IR was positively associated with incident loss of anti-HBs. The multivariable-adjusted hazard ratios (95% confidence intervals) for incident loss of anti-HBs comparing quintiles 2-5 vs quintile 1 of HOMA-IR were 1.09 (1.04-1.14), 1.14 (1.09-1.19), 1.14 (1.09-1.19) and 1.21 (1.16-1.27), respectively. These associations were stronger in younger individuals under the age of 35 than in people 35 years of age or older (P for interaction = 0.004). The association was also more evident in subjects with higher titres (≥100 mIU/mL) of anti-HBs than in those with low titres (P for interaction < 0.001). Insulin resistance was associated with an increased risk for loss of vaccine-acquired anti-HBs in a large sample of a nondiabetic, general population, indicating a possible role of insulin resistance in vaccine-induced immunity.

Triiodothyronine induces proliferation of pancreatic ß-cells through the MAPK/ERK pathway.

BACKGROUND: 3,5,3'-Triiodothyronine (T3) has a stimulatory effect on cellular growth via thyroid hormone receptors (TRs) in several cell lines. TR expression in the pancreas suggests that pancreatic beta cell proliferation might be induced by T3. The purpose of this study was to demonstrate that T3 induces pancreatic beta cell proliferation through the mitogen activated protein kinase/extracellular regulated kinase (MAPK/ERK) pathway. METHODS: INS-1 cells were plated as a monolayer at densities of 4×104, cultured in RPMI 1,640 with 10% fetal bovine serum with 2-mercaptoethanol, respectively, in 6-well multiplates. After 48 h, they were exposed to 10-7 M T3 or to vehicle alone. Viable cells were harvested after 24, 48, and 72 h of continuous exposure. Cell proliferation and TRα1 and TRß1 expression were analyzed by flow-assisted cell sorting analysis, Ki-67 staining, and Western blotting. The p38 MAPK, ERK, and Akt pathways were analyzed by Western blotting. Beta cell function was evaluated by assaying insulin secretion. RESULTS: T3 enhanced INS-1 cell proliferation at a dose of 10-7 M in a time-dependent manner via the MAPK/ERK pathway and promoted insulin secretion. CONCLUSIONS: Our results demonstrate that MAPK/ERK pathway plays an important role in the T3 induced pancreatic beta cell proliferation.

Clinical significance of CD151 overexpression in subtypes of invasive breast cancer.

BACKGROUND: CD151 is a member of the tetraspanin family, which interacts with laminin-binding integrins and other tetraspanins. This protein is implicated in motility, invasion, and metastasis of cancer cells, but the prevalence of CD151 expression in subtypes of breast cancers and its influence on clinical outcome remains to be evaluated. METHODS AND RESULTS: The immunohistochemistry-based tissue microarray analysis showed that 127 (14.3%) cases overexpressed CD151 among 886 breast cancer patients. CD151 overexpression was found to be significantly associated with larger tumour size, higher nodal stage, advanced stage, absence of oestrogen receptor and progesterone receptor, and human epidermal growth factor receptor 2 overexpression. CD151 overexpression resulted in poorer overall survival (OS) (P<0.001) and disease-free survival (P=0.02), and stage II and III patients with CD151 overexpression demonstrated substantially poorer OS (P=0.0474 and 0.0169). In the five subtypes analyses, CD151 overexpression retained its adverse impact on OS in the Luminal A (P=0.0105) and quintuple-negative breast cancer (QNBC) subtypes, one subgroup of triple-negative breast cancer (P=0.0170). Multivariate analysis that included stage, subtype, and adjuvant chemotherapy showed that CD151 overexpression was independently associated with poor OS in invasive breast cancer. CONCLUSION: CD151 overexpression may be a potential molecular therapeutic target for breast cancer, especially in QNBC subtype and more advanced stages of breast cancer.

Evaluation of the nucleated red blood cell count in neonates using the Beckman Coulter UniCel DxH 800 analyzer.

INTRODUCTION: Nucleated red blood cell (NRBC) count is closely associated with the prognosis of neonates. The analysis of NRBC has traditionally been measured manually. Recently, a newly developed automated hematology analyzer, the UniCel DxH 800 (DxH 800), was released. The goal of our study was to evaluate the performance of the DxH 800 NRBC method in neonates with the reference manual method and against previous generation hematology analyzers. METHODS: NRBCs were counted in 162 neonatal blood samples using the DxH 800, LH 750, and ADVIA 2120 vs. the reference manual technique. The concordance rate, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained. RESULTS: The DxH 800 showed an R(2) value of 0.945 and the concordance rate of 93.8%. Further assessment revealed 85.3% sensitivity, 96.1% specificity, 85.3% PPV, and 96.1% NPV, resulting in the highest area under the curve (0.961). The LH 750 and ADIVA 2120 demonstrated R(2) values of 0.851 and 0.529, respectively. CONCLUSION: The results obtained indicate the UniCel DxH 800 to be an excellent test on neonatal blood and superior to the other analyzers. Therefore, the DxH 800 is an effective and highly sensitive system for the analysis of NRBCs on newborns.

The sphingosine kinase activator K6PC-5 stimulates C2C12 myoblast differentiation.

Previously, K6PC-5, a synthetic derivative of ceramide, was demonstrated to activate sphingosine kinase (SK)-1 in keratinocytes. In this study its potential biological effect in mouse myoblasts was examined. The obtained results show that K6PC-5 promotes myogenic differentiation by enhancing myogenic marker expression, differentiation index and fusion index. Interestingly, its biological action was prevented by pharmacological inhibition of SK or S1P2 receptor, in full agreement with their recognized role in myoblast differentiation. This is the first evidence that pharmacological activation of SK accelerates myogenesis and suggests that this new therapeutic strategy could be possibly employed in skeletal muscle disorders where muscle regeneration is deficient.

Sonoporation of the minicircle-VEGF(165) for wound healing of diabetic mice.

PURPOSE: The purpose of this study is to examine the efficiency of sonoporation with minicircle DNA for the skin wound healing in diabetic mice. METHODS: Minicircle DNA containing the human VEGF(165) was constructed and tested in vitro. Diabetes was induced in 2-week old male C57BL/6J mice via streptozotocin (STZ) injection. 6 mm circular skin wounds were made on the mice back. After the subcutaneous injection of the minicircle DNA at the edge of the wound, the mice were exposed to the ultrasound irradiation for the sonoporation. Wound areas were analyzed until the day 12. Blood perfusion and angiogenesis were evaluated using a laser Doppler imaging and CD31 immunostaining, respectively. Re-epithelialization was assessed by histochemical analysis using hematoxylin and eosin staining. RESULTS: Accelerated wound closure was observed in the mice receiving sonoporation of minicircle-VEGF(165), which corresponds to the markedly increased skin blood perfusion and CD31 expression. Histological analysis revealed that the minicircle treated wound tissues showed fully restored normal architectures as compared with the non-treated diabetic controls with the markedly edematous and chaotic morphologies. CONCLUSIONS: Ultrasound mediated gene therapy with the minicircle-VEGF(165) is effective for the healing of the skin wound of the diabetic mice.

Identification of mutations in the F9 gene including exon deletion by multiplex ligation-dependent probe amplification in 33 unrelated Korean patients with haemophilia B.

Haemophilia B (HB) is a rare X-linked recessive bleeding disorder caused by a mutation in the F9 gene. The aims of this study were to characterize the mutation spectrum of F9 in Korean patients with HB to establish the optimal molecular diagnostic strategy and to find genotype-phenotype correlations. Study subjects consisted of 33 unrelated Korean patients with HB. We performed polymerase chain reaction (PCR) amplification and direct sequencing of all exons and flanking sequences of F9. When large deletion was suspected from PCR failure, exon dosage test using multiplex ligation-dependent probe amplification (MLPA) was performed. We identified disease-causing mutations in 32 out of 33 patients by direct sequencing analyses (mutation detection rate, 97%). A total of 28 unique mutations were detected, including 7 novel ones. Six mutations were recurrent but observed in no more than two patients. In the remaining one patient, exon 1 was not amplified, and MLPA analysis confirmed a large deletion involving exon 1. The genotype-phenotype correlations between the type of mutation and the severity of factor deficiency were not consistent, as has been previously reported. One patient developed inhibitor, and he was the patient with exon 1 deletion. Based on our results from 33 Korean patients with HB, which showed no hotspot for mutations, direct sequencing of all exons with flanking sequences is needed as the first-line test. MLPA can be a feasible platform at clinical laboratories to detect large deletion mutations in suspected cases.

Expression profile of tight junction protein claudin 3 and claudin 4 in ovarian serous adenocarcinoma with prognostic correlation.

Tight junction proteins claudin 3 (CLDN3) and claudin 4 (CLDN4) are frequently altered in several human cancers, including ovarian carcinomas. Here, we examined the gene expression of CLDN3 and CLDN4 in various tumors, including 19 normal ovaries and 47 ovarian carcinomas by analyzing Affymetrix HG-U133 array data. Furthermore, a total of 114 ovarian serous tumors, including 10 adenomas, 20 borderline tumors and 84 carcinomas, were analyzed immunohistochemically to confirm the expression of two proteins and we assessed the association of their expression with the clinicopathological characteristics and survival of the patients. The microarray experiment revealed CLDN3 and CLDN4 transcripts were significantly up-regulated by 5-fold or more in most subtypes of ovarian epithelial carcinomas while the immunohistochemical analyses indicated that each protein was expressed in 68 (81.0%) and 72 (85.7%) of 84 serous adenocarcinomas, respectively. Borderline serous tumors and adenomas showed significantly lower expression of these proteins than the adenocarcinomas. Kaplan-Meier survival analysis showed that serous adenocarcinoma patients with high CLDN3 expression had substantially shorter survival (P=0.027). Multivariate analysis demonstrated that CLDN3 overexpression is an independent negative prognostic factor. Our findings suggest that CLDN3 overexpression can be used as a prognostic indicator in ovarian serous carcinomas. Moreover, CLDN3 may be a promising target for antibody-based therapy of ovarian carcinomas.

Differences in sensitivity of vanilloid receptor 1 transfected to human embryonic kidney cells and capsaicin-activated channels in cultured rat dorsal root ganglion neurons to capsaicin receptor agonists.

Heterologously expressed vanilloid receptor 1 (VR1), a cloned cDNA encoding for capsaicin (CAP)-sensitive currents, resembles the native CAP channels in cultured sensory neurons in channel property. But, the pharmacological profile of VR1 to various CAP analogs is not known. The stable expression of VR1 in human embryonic kidney (HEK) cells was generated and confirmed by reverse transcription-polymerase chain reaction and Western blots. VR1 expressed in HEK cells retained single-channel properties similar to those of the native channels. When concentration-response relationships were compared, CAP and DA-5018.HCl, a synthetic analog of CAP, exhibited a greater potency in activating VR1 than the native channels in sensory neurons. In contrast, resiniferatoxin and its analog, phorbol 12-phenylacetate 13-acetate 20-homovanillate, was more potent in activating the CAP-activated channels in cultured sensory neurons than VR1. Thus, the difference in pharmacological profiles of VR1 and the native channels suggests the possible presence of subtypes of the CAP receptor or regulatory mechanisms associated with VR1.

Depressed convulsions by diazepam and its effects on brain monoamines and amino acids in E1 mice.

The effect of diazepam on inbred mutant E1 mice, which develop convulsive seizures after repeated sessions of being tossed up, was examined. Acute administration of diazepam (32 mg/kg, i.p.) completely inhibited the convulsions. At that time, the dopamine level was increased in the cortex and hippocampus, and the norepinephrine level in the cerebellum was decreased. 5-Hydroxytryptamine levels were not changed. As for amino acids, the glutamine level increased and the levels of GABA, glutamic acid, aspartic acid, alanine and other amino acids were not changed.