Induction Of Glucose Research Articles

Txnip inhibits porcine adipocyte differentiation through PPARγ and impairs the induction of glucose via ChREBP

Txnip inhibits porcine adipocyte differentiation through PPARγ and impairs the induction of glucose via ChREBP

Betulinic acid and its ionic derivatives impaired growth of prostate cancer cells without induction of GRP78 and CHOP

Abstract Prostate cancer (PCa) is the most common invasive malignancy for men in the USA. The incidence and mortality rates of PCa are significantly higher among African American men, as compared to those in Caucasian men. Betulinic acid (BA) is a penta-cyclic triterpenoid that is often found in the bark of several species of plants. It possesses a variety of biological activities, including anti-cancer activities. We examined the cytotoxic effects and endoplasmic reticulum (ER) stress induced by BA and its ionic derivatives with PCa cells derived from African Americans and Caucasian men. The viability of all PCa cells was reduced by the BA compounds, and the cytotoxicity of these BA compounds was independent of ethnicity and androgen dependency. The BA compounds induced modest effects on ER stress proteins when compared with ER stress inducers, tunicamycin and thapsigargin. The induction of glucose regulated protein 78 (GRP78) was largely correlated with the expression of C/EBP homologous protein (CHOP) and cleaved poly [ADP-ribose] polymerase (PARP)/caspase-3 in the PCa cells. In summary, our data demonstrated that BA compounds impaired the growth of PCa cells regardless of ethnicity – through GRP78- and CHOP-independent pathways.

Amyloid-β aggregates induced by β-cholesteryl glucose-embedded liposomes

Senile plaques that is characterized as an amyloid deposition found in Alzheimer's disease are composed primarily of fibrils of an aggregated peptide, amyloid β (Aβ). The ability to monitor senile plaque formation on a neuronal membrane under physiological conditions provides an attractive model. In this study, the growth behavior of amyloid Aβ fibrils in the presence of liposomes incorporating β-cholesteryl-D-glucose (β-CG) was examined using total internal reflection fluorescence microscopy, transmittance electron microscopy, and other spectroscopic methods. We found that β-CG on the liposome membrane induced the spontaneous formation of spherulitic Aβ fibrillar aggregates. The β-CG cluster formed on liposome membranes appeared to induce the accumulation of Aβ, followed by the growth of the spherulitic Aβ aggregates. In contrast, DMPC and DMPC incorporated cholesterol-induced fibrils that are laterally associated with each other. A comparison study using three types of liposomes implied that the induction of glucose contributed to the agglomeration of Aβ fibrils and liposomes. This agglomeration required the spontaneous formation of spherulitic Aβ fibrillary aggregates. This action can be regarded as a counterbalance to the growth of fibrils and their toxicity, which has great potential in the study of amyloidopathies.

Glucose induces metabolic reprogramming in neutrophils during type 2 diabetes to form constitutive extracellular traps and decreased responsiveness to lipopolysaccharides

Recurrent infections are one of the common morbidities in Type 2 Diabetes (T2D) subjects. Bidirectional activation of innate immune cells such as neutrophils and glucose metabolism in T2D conditions leads to a pro-inflammatory milieu and reduced neutrophil function, which can be a potential cause for recurrent infections. In pathological conditions of sterile inflammation associated T2D, neutrophils form constitutive extracellular traps (NETs) due to hyperglycemia and respond poorly to infections. The present study was aimed at understanding the cellular and metabolic consequences, and NETs formation in T2D. We show that glucose induces NADPH oxidase derived reactive oxygen species and further citrullinates the histones to form weaker NETs leading to reduced response to lipopolysaccharide (LPS). Untargeted metabolomics analysis in neutrophils cultured under high glucose and from T2D subjects revealed enrichment of polyol pathway intermediates (1-anhydrosorbitol) and reduced glutathione metabolism products (cysteinylglycine). NADPH is an absolute requirement for three independent pathways of formation of 1-anhydrosorbitol via aldose reductase under excess glucose, induction of glutathione synthesis and glucose induced NETs formation. During T2D and in presence of high glucose, there is a competition for NADPH between these processive reactions, which leads to its insufficiency to produce NETs in response to LPS. Interestingly, supplementation of NADPH and pharmacological inhibitor of aldose reductase, ranirestat, restored NETs formation in presence of LPS. Our study provides novel insights on the metabolic reprogramming of neutrophils, which may lead to susceptibility of T2D subjects to infections.

XIST silencing alleviated inflammation and mesangial cells proliferation in diabetic nephropathy by sponging miR-485

In this study, we investigated the role of XIST in the development of diabetic nephropathy (DN) and further explored its underlying mechanism. qRT-PCR was used to examine the level of XIST in serum of DN patients. ELISA, MTT, and flow cytometry were used to investigate the effect of XIST on biological functions of human mesangial cells (HMCs) treated with high glucose. The recovery experiments were used to explore the potential mechanism. The result showed XIST expression was elevated significantly in serums of DN patients. XIST silencing alleviated the induction of high glucose in biological behaviour of HMCs. Besides, miR-485 inhibitor revised the suppression by si-XIST in biological behaviour of high glucose induced HMCs. Furthermore, PSMB8 mimic relieved the inhibition of si-XIST in biological behaviour of high glucose induced HMCs. In short, XIST silencing could alleviate biological process and inflammation of HMCs treated with high glucose by sponging miR-485.

LncRNA TUG1 inhibits the proliferation and fibrosis of mesangial cells in diabetic nephropathy via inhibiting the PI3K/AKT pathway.

To elucidate the potential function of long non-coding RNA (lncRNA) TUG1 in the progression of diabetic nephropathy (DN) and the underlying mechanism. Rat diabetes mellitus (DM) model was established by streptozocin (STZ) administration. In vivo levels of TUG1 and relative genes in the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in DM rats and control rats were determined by the quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Moreover, levels of kidney weight, 24 h-urine protein, blood urea nitrogen and serum creatinine in DM rats and controls were detected. Mesangial cells were subjected to induction of high-level glucose. Relative levels of TUG1 and relative genes in the PI3K/AKT pathway in mesangial cells were determined as well. Through Cell Counting Kit-8 (CCK-8) and 5-Ethynyl-2'-deoxyuridine (EdU) assay, the regulatory effect of TUG1 on the proliferative ability of mesangial cells induced with high-level glucose was evaluated. Finally, expression changes in the PI3K/AKT pathway and extracellular matrix (ECM)-related genes in mesangial cells were determined. TUG1 was downregulated in DM rats and mesangial cells induced with high-level glucose. Compared with controls, DM rats presented higher levels of kidney weight, 24 h-urine protein, blood urea nitrogen and serum creatinine, which were markedly reduced after TUG1 overexpression in vivo. Moreover, overexpression of TUG1 downregulated TGF-β1, FN, and COL-IV, and inhibited the activation of the PI3K/AKT pathway. TUG1 is downregulated in DN. The overexpression of TUG1 could suppress the proliferation and ECM accumulation of mesangial cells via inhibiting the PI3K/AKT pathway.

383-P: The Potential Role of Il-6 in Defective Glucose Sensing following Recurrent Hypoglycaemia

Hypoglycaemia is common in insulin-treated therapy in the management of type 1 and long duration type 2 diabetes. Hypoglycemia evokes a significant stress response stimulating the release of several inflammatory mediators including interleukin 6 (IL-6). Importantly, glial cells also release IL-6 in response to glucose deprivation. We have previously demonstrated a role for IL-6 in the induction of defective neuronal glucose sensing in vitro. Here we investigate the potential role of IL-6 in the development of defective counter-regulatory response (CRR) to hypoglycaemia in vivo. IL-6Ra-/- mice were generated by crossing IL-6RaFlx/flx with Nestin-Cre+/-animals. Male IL-6Ra-/- and Cre+/- animals (Control) 18 weeks old, n=10/12 per group) were fed standard laboratory chow for 20 weeks. Hormonal response to hypoglycaemia was assessed in vivo by hyperinsulinaemic-hypoglycaemic clamps. Plasma epinephrine and glucagon were measured by ELISA in response to either acute (single hypo; AH) or recurrent (3 episodes per week for 4 weeks; RH) hypoglycaemia. Data are expressed as mean±SEM. The epinephrine response to hypoglycaemia was significantly elevated (>3 fold higher) in male IL-6Ra-/- animals following AH when compared to their control counterparts (0.38±0.09 vs. 1.31±0.28 delta; p<0.05). Plasma glucagon levels were comparable between genotypes (p=ns). In contrast, there was a significant suppression of the CRR to hypoglycaemia in both Control and IL-6Ra-/- animals following RH. Indeed, both IL-6Ra-/- and Control animals had suppressed epinephrine (50% and 68% reduction) and glucagon (65% and 44% reduction) responses to following RH when compared to their non-RH counterparts. These findings highlight an important role for central IL-6 signaling in response to acute hypoglycemia, however, additional mechanisms appear to contribute to the development of defective CRR following RH. Disclosure A.D. McNeilly: None. J. Gallagher: None. R.J. McCrimmon: Advisory Panel; Self; Eli Lilly and Company, Novo Nordisk A/S, Sanofi-Aventis. Research Support; Self; The Leona M. and Harry B. Helmsley Charitable Trust. Funding Diabetes UK

Suppression of stress induction of the 78-kilodalton glucose regulated protein (GRP78) in cancer by IT-139, an anti-tumor ruthenium small molecule inhibitor

In many cancers, combination therapy regimens are successfully improving response and survival rates, but the challenges of toxicity remain. GRP78, the master regulator of the unfolded protein response, is emerging as a target that is upregulated in tumors, specifically following treatment, and one that impacts tumor cell survival and disease recurrence. Here, we show IT-139, an antitumor small molecule inhibitor, suppresses induction of GRP78 from different types of endoplasmic reticulum (ER) stress in a variety of cancer cell lines, including those that have acquired therapeutic resistance, but not in the non-cancer cells being tested. We further determined that IT-139 treatment exacerbates ER stress while at the same time suppresses GRP78 induction at the transcriptional level. Our studies revealed a differential effect of IT-139 on chaperone protein family expression at multiple levels in different cancer cell lines. In xenograft studies, IT-139 decreased BRAF inhibitor upregulation of GRP78 expression in the tumor, while having minimal effect on GRP78 expression in the adjacent normal cells. The preferential decrease in GRP78 levels in tumor cells over normal cells, supported by the manageable safety profile seen in the Phase 1 clinical trial, reinforce the value IT-139 brings to combination therapies as it continues its clinical development.

Ganho de peso e alterações metabólicas em camundongos submetidos à dieta hiperlipídica

Objetivo: Avaliar a eficiência da dieta hiperlipídica na indução da obesidade e nas alterações do metabolismo da glicose e dos lipídeos, em camundongos C57BL/6.Materiais e Métodos: Utilizou-se 19 camundongos C57BL/6, divididos em grupo controle (dieta comercial; n=9) e experimental (dieta hiperlipídica; n=10). Foi mensurado o consumo de ração e ganho de peso durante 12 semanas, e calculado o Coeficiente de Eficiência Alimentar (CEA) e Índice Aterogênico. Foi realizado o Teste Oral de Tolerância à Glicose (TOTG), e construída a curva glicêmica, sendo verificada a área sobre a curva (AUC). Foram dissecados o fígado e os sítios de tecido adiposo (TA), feita análise histológica do fígado e TA epididimal, calculado o Índice de Adiposidade (IA%) e mensurada a concentração do colesterol total e frações, glicose e triglicerídeos séricos.Resultados: O grupo experimental apresentou menor consumo de ração (p<0,001) e maior ganho de peso total (p=0,001) e CEA (p<0,001). Observou-se aumento no TA epididimal (p<0,001), retroperitoneal (p<0,001), mesentérico (p=0,002) e perirrenal (p=0,012), gordura total (p<0,001) e IA% (p<0,001) no grupo experimental. O colesterol total foi maior no grupo experimental (p=0,025) e o HDL menor no controle (p=0,005). A área dos adipócitos do grupo experimental foi maior que do controle (p=0,049). Nos demais parâmetros não houve diferença significante entre os grupos.Conclusão: Este modelo induziu a obesidade em um curto período de tempo e promoveu aumento da adiposidade visceral, com dieta de baixo custo. São necessários outros estudos visando melhorar sua eficiência e alterar de forma completa os lipídeos sanguíneos e a glicemia nos camundongos C57BL/6.

Antioxidant potential of Buriti (Mauritia flexuosa) pulp flour in diabetic rats

Buriti pulp flour (BPF) contains significant levels of antioxidants. This study evaluated the effect of BPF on biomarkers of oxidative damage in the liver, heart, and pancreas of diabetic rats. The chemical composition, antioxidant capacity, and polyphenol content of BPF were determined. Thirty-six female Fisher rats were divided into four groups: control (C); control + BPF (CB); diabetic (D); diabetic + BPF (DB). Diabetes was induced by treatment with streptozotocin. Thirty days after the induction of diabetes, glucose, total cholesterol and triacylglycerides serum levels, aminotransferase and paraoxonase activities were evaluated. Oxidative damage to lipids and proteins was assessed through thiobarbituric acid reactive substances (TBARS) and protein carbonyl analyses, respectively. Histopathological analyses were also performed. BPF contained high concentrations of phenolic compounds, lipids, and fibers, and exhibited a high capacity to neutralize the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Diabetes was evidenced by equivalent high levels of glucose in plasma from rats in the D and DB groups. Diabetic rats in both groups also presented the same increased activity of aminotransferases. Protein carbonyl levels were increased in liver, heart, and pancreas in the D compared with C group. Although treatment with BPF did not result in any histopathological alterations, it reduced significantly the levels of TBARS in the heart and protein carbonyls in the liver and heart. No effect on blood glucose and tissue histology was observed following treatment with BPF. However, BPF diminished oxidative damage in liver and heart, indicating a possible antioxidant potential in vivo, in addition to in vitro.

Potential suppression of the high glucose and insulin-induced retinal neovascularization by Sirtuin 3 in the human retinal endothelial cells

Retinal neovascularization generally play roles in the formation of various severe eye diseases, such as age-related macular degeneration and diabetic retinopathy. The regulation of neovascularization-related pathways by Sirtuin 3 (Sirt3), a major mitochondrial NAD+-dependent deacetylase, give us a cue that Sirt3 may participate in the retinal neovascularization. However, the mechanism remains unclear. Here, we established a retinal neovascularization model by using human retinal endothelial cells (HRECs) under the induction of high glucose and insulin (HGI). With this model, Sirt3-expressing lentivirus was constructed and then used to investigate the effect of Sirt3 overexpression on the expression of migration-, neovascularization- and autophagy-related genes. After the treatment of HGI on HRECs, the mRNA and protein levels of migration-related genes, including matrix metalloproteinase-2 (MMP-2) and MMP-9, were significantly upregulated. Meanwhile, angiogenesis-related genes, including vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1α (HIF-1α), and insulin-like growth factor-1 (IGF-1) were promoted at both mRNA and protein levels. However, HGI had no clear effect on the mRNA and protein levels of microtubule associated protein 1 light chain 3 (LC3), an autophagy-related gene. When Sirt3 was overexpressed by lentivirus infection after HGI, the upregulation of MMP-2, MMP-9, VEGF, HIF-1α, and IGF-1 were suppressed at both transcription and translation levels. At the same time, LC3 mRNA and LC3-II protein increased. These results suggest that Sirt3 may inhibit retinal neovascularization by regulating the migration-, neovascularization- and autophagy-related factors expression. Thus we argue that Sirt3 may be a potential candidate drug for curing various eye diseases induced by retinal neovascularization.

Effect of metanephric mesenchyme cells on podocytes apoptosis induced by high glucose

To study the effect of metanephric mesenchyme cells on podocytes apoptosis induced by high glucose. Mice's podocyte was cultured in vitro,and apoptosis and injury model of podocyte was then established by high glucose (30 mmol/L) induction. Metanephric mesenchyme cells were extracted from E13.5 mouse embryos and used to make conditioned medium which was used to treat podocytes apoptosis. The flow cytometry and confocal fluorescence imaging were used to detect the apoptosis ratio and cytoskeletal protein (synaptopodin) expression of podocyte at several time points (24, 48, 72 h), in order to explore the effect of high glucose on podocytes and the treatment effect of metanephric mesenchyme cell conditioned medium. Significant increasing of podocyte apoptosis ratio and decreasing in synaptopodin expression contrast to control group was observed after induction of high glucose, with a statistical difference. Metanephric mesenchyme cells could be isolated from E13.5 mouse embryos successfully, and had the capacity of osteogenic and adipogenic differentiation. Metanephric mesenchyme cell conditioned medium and high glucose stimulations was used to generate podocytes cells. Compared to the group treated with high glucose stimulation, the flow cytometry detection result suggested that metanephric mesenchyme cell could reduce podocytes apoptosis in a dose-dependent manner: with increasing in the concentration of metanephric mesenchyme cell conditioned medium, the treatment effect was better. Metanephric mesenchyme cells could prevent apoptosis and injury of podocyte induced by high glucose.

Extended oxygen consumption assay reveals size dependent differences of rat islets of Langerhans

Introduction: The mitochondrial viability of islet beta cells is critical for two key functions: first, the provision of energy for maintenance of cellular metabolism and homeostasis, and second, the induction of glucose stimulated insulin secretion. Recently the measurement of the oxygen consumption rate (OCR) in combination with the isolation factor, a marker of islet size, has been proposed as a new quality control parameter of islets destined for transplantation for the therapy of type 1 diabetes.

Effect of endoplasmic reticulum (ER) stress inducer thapsigargin on the expression of extracellular-superoxide dismutase in mouse 3T3-L1 adipocytes

Endoplasmic reticulum stress is related to metabolic disorders, including atherosclerosis and type 2 diabetes. It is known that inflammatory adipocytokines and oxidative stress are increased, while anti-inflammatory adipocytokines such as adiponectin are decreased in adipocytes during above conditions. Extracellular-superoxide dismutase is an anti-inflammatory enzyme that protects cells from oxidative stress. Because plasma extracellular-superoxide dismutase levels in type 2 diabetes patients were inversely related to the body mass index and homeostasis model assessment-insulin resistance index, it is speculated that the regulation of extracellular-superoxide dismutase might lead to the suppression of metabolic disorders. Here, we observed the reduction of extracellular-superoxide dismutase and adiponectin in 3T3-L1 adipocytes treated with thapsigargin, an endoplasmic reticulum stress inducer. Interestingly, tunicamycin, another endoplasmic reticulum stress inducer, did not decrease the expression of extracellular-superoxide dismutase in spite of the induction of glucose regulated protein kinase 78 kDa, an endoplasmic reticulum stress marker. Moreover, eukaryotic translation initiation factor 2α signaling cascade plays a pivotal role in the reduction of extracellular-superoxide dismutase in 3T3-L1 adipocytes during endoplasmic reticulum stress conditions.

Molecular Identification and Physiological Characterization of a Putative Novel Plasma Membrane Protein from Arabidopsis Involved in Glucose Response

We carried out functional analysis of a putative novel Arabidopsis plasma membrane glucose-responsive regulator, designated AtPGR, which contains seven predicted transmembrane domains. Several evidences showed that AtPGR is a glucose-related protein, but its biological functions have yet to be reported in any plant. Analyses of the AtPGR promoter-β-glucuronidase (GUS) construct and RNA in situ hybridization revealed substantial gene expression in the vasculature of various tissues, especially in the phloem region. Glucose treatment induced the highest levels of GUS activity, reaching a peak at 3 h and declining thereafter, consistent with glucose-mediated regulation of the AtPGR promoter. We generated an atpgr RNAi knockdown mutant and found that this plant grew and developed normally. Ectopic expression of AtPGR gene modulated the induction of glucose and 2-deoxyglucose insensitivity under stress conditions. By way of contrast, cotyledon greening of atpgr RNAi knockdown mutant seeds enhanced sensitivity to glucose and 2-deoxyglucose. Taken together, these results suggest that AtPGR functions as a potential glucose-responsive regulator in carbohydrate metabolism.

Protective effect of taurine on diabetic rat endothelial dysfunction

As increasing evidence suggest that oxidative stress plays an important role in the developing angiopathy in diabetes, we studied the effects of taurine, a free radical scavenger, on diabetes induced angiopathy in the rat aorta. Six-week-old male Wistar rats were randomly divided into three groups; control group (Cont), diabetes group (DM) and diabetes group treated with taurine for four weeks, 500 mg/kg/day, intraperitoneally (i.p.) (DM+T). Diabetes was induced by streptozotocin (50 mg/kg i.p.). Four weeks after the induction of diabetes, serum glucose and malondialdehyde concentrations were measured. Additionally, organ bath studies and real-time PCR on muscarinic M(3) receptor and eNOS were performed. Although taurine treatment failed to decrease serum glucose levels, the increased serum malondialdehyde levels in diabetic rats were significantly decreased after taurine treatment. Norepinephrine-induced hyper-contractility as well as acetylcholine-induced, endothelium-dependent hypo-relaxation in diabetes were significantly prevented after taurine treatment. The differences in the expressions of muscarinic M(3) receptor mRNAs were statistically non-significant between groups. Moreover, diabetes-induced up-regulation of eNOS mRNAs was slightly prevented after taurine treatment. These data suggest that taurine acts beneficially against the diabetes-induced vascular dysfunction. Its potential action as a radical scavenger ameliorates the vascular disorders in diabetes.

Foldamer Organogels: A Circular Dichroism Study of Glucose-Mediated Dynamic Helicity Induction and Amplification

This paper reports a systematic study of the dynamic process for the self-assembly of chiral organogels from achiral hydrogen bonded hydrazide foldamers by induction of chiral glucose. Six foldamers incorporated with six decyl chains and two benzene, naphthalene, anthracene, or pyrene units at the ends are revealed to strongly gelate apolar and polar solvents, including alkanes, arenes, esters, alcohols, and 1,4-dioxane. The gels are characterized by UV-vis, fluorescent, XRD, SEM, and AFM methods, based on which a dislocated "tail-to-tail" stacking pattern is proposed. Addition of octylated glucose considerably enhances the capacity of the foldamers to gelate apolar solvents due to strong complexation. The complexation also causes unique dynamic helicity induction in the gels, which is studied systematically by circular dichroism. The results are treated with the Avrami theory according to a reported method (J. Am. Chem. Soc. 2005, 127, 4336), which suggests that the gelation involves a nucleation-elongation mechanism. In addition, the "Sergeants and Soldiers" effect in the gel phase is also revealed.

Dopamine melanin‐loaded PC12 cells: a model for studies on pigmented neurons

The most conspicuous feature in idiopathic parkinsonism is the degeneration of pigmented neurons in the substantia nigra. A major problem for the study of the significance of neuromelanin for the development of parkinsonism is that common experimental animals lack neuromelanin in substantia nigra. The aim of this study was to develop an in vitro model that could be used to study the role of neuromelanin in chemically induced toxicity in dopaminergic cells. Cultured neuron-like PC12 cells were exposed to synthetic dopamine melanin (0-1.0 mg/ml) for 48 h, resulting in uptake of dopamine melanin particles into the cells. The intracellular distribution of dopamine melanin granules was similar to that found in neuromelanin-containing neurons. Dopamine melanin, up to 0.5 mg/ml, had negligible effects on ultrastructure, induction of the endoplasmic reticulum-stress protein glucose regulating protein 78, activation of caspase-3 and cell viability. The decreased cell viability in response to the cytotoxic peptide amyloid-beta25-35 was similar in melanin-loaded cells and in control cells without melanin. The results of the studies suggest that melanin-loaded PC12 cells can serve as an in vitro model for studies on the role of neuromelanin for the toxicity of chemicals, in particular neurotoxicants with melanin affinity, in pigmented neurons.

Regulation and recognition of SCFGrr1 targets in the glucose and amino acid signaling pathways.

SCFGrr1, one of several members of the SCF family of E3 ubiquitin ligases in budding Saccharomyces cerevisiae, is required for both regulation of the cell cycle and nutritionally controlled transcription. In addition to its role in degradation of Gic2 and the CDK targets Cln1 and Cln2, Grr1 is also required for induction of glucose- and amino acid-regulated genes. Induction of HXT genes by glucose requires the Grr1-dependent degradation of Mth1. We show that Mth1 is ubiquitinated in vivo and degraded via the proteasome. Furthermore, phosphorylated Mth1, targeted by the casein kinases Yck1/2, binds to Grr1. That binding depends upon the Grr1 leucine-rich repeat (LRR) domain but not upon the F-box or basic residues within the LRR that are required for recognition of Cln2 and Gic2. Those observations extend to a large number of Grr1-dependent genes, some targets of the amino acid-regulated SPS signaling system, which are properly regulated in the absence of those basic LRR residues. Finally, we show that regulation of the SPS targets requires the Yck1/2 casein kinases. We propose that casein kinase I plays a similar role in both nutritional signaling pathways by phosphorylating pathway components and targeting them for ubiquitination by SCFGrr1.

Edaravone protects against hypoxia/ischemia-induced endoplasmic reticulum dysfunction.

Endoplasmic reticulum (ER) stress-induced cell death plays an important role in cerebral ischemia. In the present study, we investigated whether edaravone (3-methyl-1-phenyl-pyrazolin-5-one), a free radical scavenger, can protect against ER damage induced by cerebral ischemia. In a mouse model of hypoxia/ischemia, treatment with edaravone reduced edema-corrected infarction volume, attenuated hemispheric swelling, and improved neurological status. Moreover, edaravone suppressed ER stress-mediated apoptosis by inhibiting eukaryotic initiation factor alpha phosphorylation, C/EBP homologous protein (CHOP) induction, and caspase-12 activation. In mouse primary cultured glial cells, edaravone attenuated ER stress as evidenced by inhibition of the induction of glucose regulated protein 78 and CHOP and XBP-1 splicing under treatment with tunicamycin (Tm), which induces ER stress. Tm did not induce the production of reactive oxygen species in primary cultured glial cells. In addition, the free radical scavengers N-acetyl-l-cysteine and ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] did not affect ER stress response caused by Tm. These results demonstrated a novel action of edaravone that can protect against ER dysfunction in cerebral ischemia.