Binding of an arm repeat protein to the kinase domain of the S-locus receptor kinase

Screening of a yeast two-hybrid library for proteins that interact with the kinase domain of an S-locus receptor kinase (SRK) resulted in the isolation of a plant protein called ARC1 (Arm Repeat Containing). This interaction was mediated by the C-terminal region of ARC1 in which five arm repeat units were identified. Using the yeast two-hybrid system and in vitro binding assays, ARC1 was found to interact specifically with the kinase domains from SRK-910 and SRK-A14 but failed to interact with kinase domains from two different Arabidopsis receptor-like kinases. In addition, treatment with a protein phosphatase or the use of a kinase-inactive mutant reduced or abolished the binding of ARC1 to the SRK-910 kinase domain, indicating that the interaction was phosphorylation dependent. Lastly, RNA blot analysis revealed that the expression of ARC1 is restricted to the stigma, the site of the self-incompatibility response.

New susceptibility loci associated with kidney disease in type 1 diabetes

Diabetic kidney disease, or diabetic nephropathy (DN), is a major complication of diabetes and the leading cause of end-stage renal disease (ESRD) that requires dialysis treatment or kidney transplantation. In addition to the decrease in the quality of life, DN accounts for a large proportion of the excess mortality associated with type 1 diabetes (T1D). Whereas the degree of glycemia plays a pivotal role in DN, a subset of individuals with poorly controlled T1D do not develop DN. Furthermore, strong familial aggregation supports genetic susceptibility to DN. However, the genes and the molecular mechanisms behind the disease remain poorly understood, and current therapeutic strategies rarely result in reversal of DN. In the GEnetics of Nephropathy: an International Effort (GENIE) consortium, we have undertaken a meta-analysis of genome-wide association studies (GWAS) of T1D DN comprising ~2.4 million single nucleotide polymorphisms (SNPs) imputed in 6,691 individuals. After additional genotyping of 41 top ranked SNPs representing 24 independent signals in 5,873 individuals, combined meta-analysis revealed association of two SNPs with ESRD: rs7583877 in the AFF3 gene (P = 1.2 × 10(-8)) and an intergenic SNP on chromosome 15q26 between the genes RGMA and MCTP2, rs12437854 (P = 2.0 × 10(-9)). Functional data suggest that AFF3 influences renal tubule fibrosis via the transforming growth factor-beta (TGF-β1) pathway. The strongest association with DN as a primary phenotype was seen for an intronic SNP in the ERBB4 gene (rs7588550, P = 2.1 × 10(-7)), a gene with type 2 diabetes DN differential expression and in the same intron as a variant with cis-eQTL expression of ERBB4. All these detected associations represent new signals in the pathogenesis of DN.

A new marker for mosaic analysis in Caenorhabditis elegans indicates a fusion between hyp6 and hyp7, two major components of the hypodermis

A fusion of the sur-5 protein to the green fluorescent protein containing a nuclear localization signal is demonstrated as a marker for genetic mosaic analysis in the nematode Caenorhabditis elegans. Because of an extensive accumulation of bright fluorescence in many nuclei, normal growth plates, each containing hundreds of worms, can be rapidly screened with a dissecting microscope for rare mosaic individuals. As the marker can also be used to detect transgenic worms, the construction of strains for mosaic analyses can be minimized. In the course of examining rare mosaic animals, an unexpected pattern of fluorescence was noticed for hyp6, a syncytial component of the hypodermis, which indicated that the marker may serve as a means of assessing cellular fusions during development. Immunofluorescent staining of adherens junctions confirmed a postembryonic fusion of hyp6 with hyp7, the major syncytium of the hypodermis.

An updatable holographic three-dimensional display

Holographic three-dimensional (3D) displays provide realistic images without the need for special eyewear, making them valuable tools for applications that require situational awareness, such as medical, industrial and military imaging. Currently commercially available holographic 3D displays use photopolymers that lack image-updating capability, resulting in restricted use and high cost. Photorefractive polymers are dynamic holographic recording materials that allow updating of images and have a wide range of applications, including optical correlation, imaging through scattering media and optical communication. To be suitable for 3D displays, photorefractive polymers need to have nearly 100% diffraction efficiency, fast writing time, hours of image persistence, rapid erasure, and large area-a combination of properties that has not been shown before. Here, we report an updatable holographic 3D display based on photorefractive polymers with such properties, capable of recording and displaying new images every few minutes. This is the largest photorefractive 3D display to date (4 x 4 inches in size); it can be recorded within a few minutes, viewed for several hours without the need for refreshing, and can be completely erased and updated with new images when desired.

Caenorhabditis elegans SUR-5, a novel but conserved protein, negatively regulates LET-60 Ras activity during vulval induction

The let-60 ras gene acts in a signal transduction pathway to control vulval differentiation in Caenorhabditis elegans. By screening suppressors of a dominant negative let-60 ras allele, we isolated three loss-of-function mutations in the sur-5 gene which appear to act as negative regulators of let-60 ras during vulval induction. sur-5 mutations do not cause an obvious mutant phenotype of their own, and they appear to specifically suppress only one of the two groups of let-60 ras dominant negative mutations, suggesting that the gene may be involved in a specific aspect of Ras activation. Consistent with its negative function, overexpressing sur-5 from an extragenic array partially suppresses the Multivulva phenotype of an activated let-60 ras mutation and causes synergistic phenotypes with a lin-45 raf mutation. We have cloned sur-5 and shown that it encodes a novel protein. We have also identified a potential mammalian SUR-5 homolog that is about 35% identical to the worm protein. SUR-5 also has some sequence similarity to acetyl coenzyme A synthetases and is predicted to contain ATP/GTP and AMP binding sites. Our results suggest that sur-5 gene function may be conserved through evolution.

Impact of the hypoxia-inducible factor-1 α (HIF1A) Pro582Ser polymorphism on diabetes nephropathy

OBJECTIVE

Hypoxia plays a major pathogenic role in diabetic nephropathy (DN). We have investigated in this study the effect of hypoxia-inducible factor 1 α subunit (HIF1A) genetic polymorphisms on the development of DN.

RESEARCH DESIGN AND METHODS

In 1,165 American type 1 diabetic patients with and without DN selected from the Genetics of Kidneys in Diabetes (GoKinD) study, the HIF1A genetic polymorphisms were genotyped with TaqMan allelic discrimination. The regulation of HIF-1α in the kidneys of diabetic mice was appreciated by immunohistochemistry, and the effect HIF1A Pro582Ser polymorphism on HIF-1α sensitivity to glucose was evaluated in vitro.

RESULTS

We identified a protective association between HIF1A Pro582Ser polymorphism and DN in male subjects. We also provided mechanistic insights that HIF-1α is repressed in the medulla of diabetic mice despite hypoxia and that Pro582Ser polymorphism confers less sensitivity to the inhibitory effect of glucose during a hypoxic challenge.

CONCLUSIONS

The current study demonstrates for the first time that HIF1A Pro582Ser polymorphism has an effect on DN, possibly by conferring a relative resistance to the repressive effect of glucose on HIF-1α.

Two members of the thioredoxin-h family interact with the kinase domain of a Brassica S locus receptor kinase

To determine potential targets of the S locus receptor kinase (SRK) during the Brassica self-incompatibility response, a yeast two-hybrid library was screened with the SRK-910 protein kinase domain. Two thioredoxin-h-like clones, THL-1 and THL-2, were found to interact specifically with the SRK-910 protein kinase domain and not to interact with the protein kinase domains from the Arabidopsis receptor-like protein kinases (RLK) RLK4 and RLK5. The interaction between THL-1 and the SRK-910 protein kinase domain was confirmed using coimmunoprecipitation experiments with fusion proteins produced in Escherichia coli. THL-1 has thioredoxin activity based on an insulin reduction assay, and THL-1 is weakly phosphorylated by the SRK-910 protein kinase domain. THL-1 and THL-2 are both expressed in a variety of tissues but show some differences in steady state mRNA levels, with THL-2 being preferentially expressed in floral tissues. This indicates a more general biological function for these thioredoxins in addition to a potential role as effector molecules in the self-incompatibility signal cascade.

Increased heterologous protein production in Aspergillus niger fermentation through extracellular proteases inhibition by pelleted growth

The dependence of filamentous fungal protease secretion on morphology was investigated by employing the recombinant Aspergillus niger strain AB4.1[pgpdAGLAGFP] which contains a gene for the glucoamylase-GFP (green fluorescence protein) fusion protein. Different inoculum levels were used to obtain different sizes of pellet or free mycelia. The extracellular protease activity of the cultures varied with the pellet size and decreased dramatically when the morphology was changed from free mycelia to pellets. The culture with an optimal pellet size of 1.6 mm was obtained from an inoculum of 4 x 10(6) spores/mL. It resulted in a specific protease activity of 158 units/L, only one-third of that in free mycelial growth, and a maximum specific GFP yield of 0.98 mg/g (cell mass) compared to 0. 29 mg/g for free mycelial growth with an inoculum of 10(7) spores/mL. The results indicate that this bioprocessing strategy can be effectively used to inhibit protease activity in filamentous fungal fermentation and thereby to enhance heterologous protein production.

Adherence to oral second-generation antipsychotic medications in patients with schizophrenia and bipolar disorder: physicians' perceptions of adherence vs. pharmacy claims

OBJECTIVE

To compare physician-reported adherence of specific patients to oral second-generation antipsychotics vs. actual adherence rates determined from the patients' pharmacy claims.

METHODS

Claims data from the HealthCore Integrated Research Database identified patients with schizophrenia or bipolar disorder with ≥ 1 oral second-generation antipsychotic prescription. The prescribing physicians were identified from the pharmacy claims and asked to complete an Internet survey assessing their perception of medication adherence for 1-2 of their patients and their beliefs regarding adherence to second-generation antipsychotics in general for a 1-year period. Adherence to second-generation antipsychotics was determined for each patient by pharmacy claims for the same period. Physician survey data were merged with patient claims data via unique patient identifiers, and physician-reported adherence rates were compared with claims-based rates as measured by the medication possession ratio.

RESULTS

One hundred and fifty-three physicians responded to the survey, representing 214 patients (44 with claims for schizophrenia, 162 with bipolar disorder, 8 with claims for bipolar disorder and schizophrenia). Most physicians (60%) had no formal adherence training. More than two-thirds (68%) reported emphasising the importance of adherence and reported approximately 76% of their patients were adherent (≥ 71% of the time). In the schizophrenia group, 16 of 17 (94%) patients with low-to-moderate (≤ 70%) adherence levels had high (≥ 71%) physician-estimated adherence. In the bipolar disorder group, 62 of 92 (67%) patients with low-to-moderate adherence levels had high physician-estimated adherence.

CONCLUSIONS/INTERPRETATION

These analyses suggest that, even when physicians are asked about specific patients in their practice, there is discordance between physician perceptions and adherence as measured through pharmacy claims. This disparity may delay appropriate interventions, potentially contributing to relapses.

Regulation of sialyltransferase activities by phosphorylation and dephosphorylation

The composition of tissue gangliosides is thought to result mainly from the active regulation and selective expression of specific enzymes responsible for their metabolism. In the last few years, we have purified several rat brain sialyltransferases to homogeneity; the availability of these highly purified enzymes enabled us to investigate their regulation and expression at the molecular level. Thus, we studied the regulation of sialyltransferase activities, in particular, CMP-NeuAc:GM1 and CMP-NeuAc:LacCer sialyltransferases by a phosphorylation/dephosphorylation mechanism. Protein kinase C was added to a standard enzyme assay mixture containing [gamma-32P]ATP, and the activity of the enzyme was measured after various incubation times. We found that treatment of several sialyltransferases by protein kinase C decreased their activities in a time-dependent manner. Analyses of 32P-labeled amino acids revealed that the major phosphorylation site of CMP-NeuAc:GM1 alpha 2-->3 sialyltransferase (ST-IV) was serine and that for CMP-NeuAc:LacCer alpha 2-->3 sialyltransferase (ST-I) was primarily threonine. Partial recovery of the enzyme activity could be achieved by treatment of the phosphorylated sialyltransferases with rat brain protein phosphatase. We conclude that the activities of sialyltransferases can be modulated by protein kinase C and protein phosphatase and this may represent a potential regulatory mechanism for ganglioside biosynthesis.

Epigenetic analyses of the insulin-like growth factor binding protein 1 gene in type 1 diabetes and diabetic nephropathy

Background

Clinical observations have demonstrated that high levels of circulating insulin-like growth factor binding protein-1 (IGFBP-1) are associated with type 1 diabetes (T1D), whereas low serum IGFBP-1 levels are associated with the risk of type 2 diabetes (T2D). Recently, we reported that increased DNA methylation levels in the IGFBP1 gene were associated with T2D. In the present study, we evaluated the epigenetic changes of IGFBP1 in T1D and diabetic nephropathy (DN).

Results

In total, 778 Swedish individuals, including T1D patients with or without DN and subjects with the normal glucose tolerance (NGT), were involved in the study. IGFBP1 methylation levels in genomic DNA extracted from peripheral blood were analyzed with bisulfite pyrosequencing. Serum IGFBP-1 levels were measured with radioimmunoassay. We found that DNA methylation levels in the IGFBP1 gene were decreased (15.6% versus 16.9%; P < 0.001), whereas serum IGFBP-1 levels were increased (31 versus 24 μg/L, P = 0.003) in T1D patients compared with NGT subjects. Furthermore, T1D patients with DN had increased circulating IGFBP-1 concentration compared with the patients without DN (52 versus 28 μg/L; P = 0.006). However, no difference of the IGFBP1 DNA methylation levels between T1D patients with and without DN was observed.

Conclusions

This study shows for the first time that T1D patients had decreased DNA methylation levels in the IGFBP1 gene and further implies that increased circulating IGFBP-1 levels are associated with T1D and DN.

Increased DNA methylation levels of the insulin-like growth factor binding protein 1 gene are associated with type 2 diabetes in Swedish men

Background

Prospective studies have shown that low levels of circulating insulin-like growth factor binding protein-1 (IGFBP-1) are associated with the risk of type 2 diabetes. In the present study, we investigated DNA methylation in the IGFBP1 gene to evaluate its changes in relation to serum IGFBP-1 levels in type 2 diabetes.

Results

A total of 406 Swedish men, including age-matched normal glucose tolerance subjects and type 2 diabetes patients either newly diagnosed or undergoing treatment, were selected from the Stockholm Diabetes Prevention Program. IGFBP1 methylation levels in genomic DNA extracted from peripheral blood were analysed by bisulfite pyrosequencing. Serum IGFBP-1 levels were measured by radio-immunoassay. We found that IGFBP1 DNA methylation levels were higher in both newly diagnosed and treated type 2 diabetes patients with a mean diabetes duration of 3 years compared with subjects with normal glucose tolerance (19.8% and 20.2% vs. 16.9%, P < 0.001 for both). Serum levels of IGFBP-1 in newly diagnosed and in treated type 2 diabetes patients were lower compared with healthy individuals (18 μg/l both vs. 24 μg/l, P = 0.011, P < 0.001). IGFBP1 methylation levels but not serum IGFBP-1 levels in type 2 diabetes patients were independent of body mass index. Newly diagnosed patients with a family history of diabetes (FHD) had higher IGFBP1 methylation levels than those without FHD (20.3% vs. 18.6%, P = 0.017).

Conclusions

This study provides the first evidence that changes in DNA methylation of the IGFBP1 gene are associated with type 2 diabetes in Swedish men and suggests that increased IGFBP1 DNA methylation and decreased IGFBP-1 serum levels are features of type 2 diabetes with a short duration.

Evaluation of IGFBP-7 DNA methylation changes and serum protein variation in Swedish subjects with and without type 2 diabetes

Background

Insulin-like growth factor-binding protein 7 (IGFBP-7) is able to interact with insulin-like growth factor 1 (IGF-1) as well as insulin. Previous studies have suggested that serum IGFBP-7 levels may be associated with insulin resistance in type 2 diabetes (T2D). This study aimed to evaluate IGFBP-7 serum protein and IGFBP7 DNA methylation levels in the subjects with and without T2D.

Results

A total of 340 Swedish subjects including 100 newly diagnosed T2D patients (50 women/50 men), 100 age-matched nondiabetic control subjects (50/50) and 140 treated T2D patients (54/86) were studied. Serum IGFBP-7 levels were measured with a novel ELISA. IGF1, IGFBP-1, and insulin were determined by in-house radioimmunoassays. DNA methylation levels in the IGFBP7 gene were analyzed with a bisulfite-pyrosequencing technique. Serum IGFBP-7 protein levels were similar among nondiabetic subjects, newly diagnosed, and treated T2D patients and were not correlated with IGFBP7 DNA methylation. However, IGFBP7 DNA methylation was increased in men with newly diagnosed T2D compared with nondiabetic controls (17.6% vs. 12.5%, P < 0.01). Serum IGFBP-7 levels correlated (r = 0.331, P = 0.019) with serum IGFBP-1 levels, a marker of insulin production, in men but not women with newly diagnosed T2D.

Conclusions

This study demonstrates for the first time that IGFBP7 DNA methylation levels are increased in Swedish men with newly diagnosed T2D. The correlation between IGFBP-7 and IGFBP-1 suggests that low IGFBP-7 may be associated with insulin resistance in T2D.

Increased circulating conjugated primary bile acids are associated with hyperandrogenism in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common metabolic disorder with hyperandrogenism as the core pathophysiologic feature. Increased bile acids and altered bile acid pool composition have been implicated in the pathogenesis of several metabolic diseases. Thus, this study aimed to clarify the specific alterations in circulating bile acids in patients with PCOS and investigate its associations with hyperandrogenism. We recruited 37 patients with PCOS and 35 age- and BMI-matched control subjects. Serum bile acids and androgen profiles were assessed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Compared with control subjects, glycine- and taurine-conjugated primary bile acids were significantly elevated in patients with PCOS (P = 0.001 and P < 0.001). In addition, these conjugated primary bile acids were significantly and positively associated with serum concentrations of total testosterone and androstenedione in the PCOS group. In conclusion, increased circulating conjugated primary bile acids are positively associated with hyperandrogenism in women with PCOS. Further studies are warranted to explore the underlying mechanism.

Synthesis and electronic properties of covalent assemblies of oligophenylenevinylene units arising from a calix

Assemblies of four oligophenylenevinylene moieties arising from a calix[4]arene core, i.e., calix[4]oligophenylenevinylenes, have been prepared by Heck-type cross-coupling reactions of styrene derivatives with a tetraiodinated cone-calix[4]arene precursor. Photophysical studies in solution have revealed that there are electronic ground state interactions between the covalently bonded OPV moieties. The absorption spectra of the calix[4]oligophenylenevinylenes are significantly different from those obtained by summing the spectra of four model units and their emission is red-shifted when compared to the corresponding model compounds. Electrochemical studies have shown that the redox processes of the four OPV subunits do not take place at the same potentials indicating also a strong electronic interaction among them in the calix[4]oligophenylenevinylenes.

Ultrasound-assisted leaching of spent lithium ion batteries by natural organic acids and H2O2

Ultrasound-assisted bioacid leaching was examined for the extraction of valuable metals from spent lithium ion batteries (LIBs). In this work, organic acids in lemon juice were used as the leaching agent together with H₂O₂. Three effective factors, namely solid/liquid (S/L) ratio, lemon juice percentage, and H₂O₂ volume percentage, were optimized using Response Surface Methodology (RSM). The optimal conditions were found to be 0.98% (w/v) S/L ratio, 57.8% (v/v) lemon juice and 8.07% (v/v) H₂O₂ in the leaching liquor, achieving recovery of 100% Li, 96% Co and 96% Ni. Furthermore, the individual effects of ultrasound, H₂O₂ and lemon juice on metal recovery were studied and the results showed that without H₂O₂ or lemon juice, the metal recovery rates decreased greatly while the absence of ultrasound reduced recovery rates to a much smaller extent, indicating that both H₂O₂ and lemon juice were essential in the leaching process. The effect of time on the metals recoveries was examined and results showed that Li and Co recovery reached 100% with the leaching time of 35 min. The modified shrinking core modeling results suggested that chemical reaction was the rate controlling step.

Erythropoietin alleviates hepatic steatosis by activating SIRT1-mediated autophagy

Erythropoietin (EPO), besides its stimulatory effect on erythropoiesis, is beneficial to insulin resistance and obesity. However, its role in hepatic steatosis remains unexplored. Activating autophagy seems a promising mechanism for improving fatty liver disease. The present study investigated the role of EPO in alleviating hepatic steatosis and sought to determine whether its function is mediated by the activation of autophagy. Here, we show that EPO decreased hepatic lipid content significantly in vivo and in vitro. Furthermore, EPO/EPO receptor (EPOR) signalling induced autophagy activation in hepatocytes as indicated by western blot assay, transmission electron microscopy, and confocal microscopy. In addition, EPO increased the co-localization of autophagosomes and cellular lipids as shown by double labelling of the autophagy marker light chain microtubule-associated protein 3 (LC3) and lipids. Importantly, suppression of autophagy by an inhibitor or small interfering RNA (siRNA) abolished the EPO-mediated alleviation hepatic steatosis in vitro. Furthermore, EPO up-regulated sirtuin 1 (SIRT1) expression, and siRNA-mediated SIRT1 silencing abrogated the EPO-induced increases in LC3 protein and deacetylation levels, thereby preventing the alleviation of hepatic steatosis. Taken together, this study revealed a new mechanism wherein EPO alleviates hepatic steatosis by activating autophagy via SIRT1-dependent deacetylation of LC3. This finding might have therapeutic value in the treatment of hepatic steatosis.

IGF2BP2 and IGF2 genetic effects in diabetes and diabetic nephropathy

OBJECTIVE

The IGF2BP2 gene is located on chromosome 3q27.2 within a region linked to type 1 diabetes (T1D), type 2 diabetes (T2D) and diabetic nephropathy (DN). Its protein functionally binds to 5'-UTR of the imprinting IGF2 gene. The present study aims to evaluate the IGF2BP2-IGF2 genetic effects in diabetes and DN.

MATERIALS AND METHODS

Three cohorts including T1D with and without DN (n=1139) of European descents from the GoKinD study, Swedish T1D with and without DN (n=303) and Czech control subjects without diabetes, T1D, T2D with and without DN (n=1418) were enrolled in TaqMan genotyping experiments for IGF2BP2 rs4402960 and IGF2 rs10770125. Igf2bp2 gene expression in kidney tissues of db/db and control mice at the ages of 5 and 26 weeks was examined with real time RT-PCR and Western blot.

RESULTS

An association of IGF2BP2 rs4402960 with T2D in the Czech population was replicated. This IGF2BP2 polymorphism (P=0.037, OR=0.69 95% CI 0.49-0.98) was found to be associated with DN in male not in female patients with T1D selected from the GoKinD study. In the analyses of combined the GoKinD, Czech and Swedish populations, the association between IGF2BP2 polymorphism and DN in male patients with T1D was still significant (P=0.030, OR=0.73, 95% CI 0.54-0.97). IGF2 rs10770125 was also associated with DN in male T1D patients of the GoKinD population (P=0.038, OR=0.67 95% CI 0.46-0.98). There might be a genetic interaction between IGF2BP2 and IGF2 (P=0.05). The Igf2bp2 gene expression levels were increased in the kidneys of db/db mice compared to controls at the age of 5weeks but not at 26 weeks.

CONCLUSIONS

The present study has replicated the association of IGF2BP2 rs4402960 with T2D in the Czech population and provided data suggesting that IGF2BP2 may have genetic interaction with IGF2 with a protective effect against DN in male patients with T1D.