Curcumin activates autophagy and attenuates high glucose-induced apoptosis in HUVECs through the ROS/NF-κB signaling pathway.

Curcumin (CUR) is well known for its anti-inflammatory and antioxidant effects. However, the endothelial protective effect of CUR in diabetes and the underlying signaling pathway remains unclear. The goal of the current study was to provide evidence regarding the protective mechanism of CUR against the high glucose (HG)-induced damage to human umbilical vein endothelial cells (HUVECs). HG-induced HUVECs injury model was used to evaluate the protective effect and the underlying mechanism of CUR against endothelial injury. The cell viability was determined by the MTT method. The cell reactive oxygen species (ROS) were determined by using flow cytometry. The protein expression levels of Bcl-2, Bax, LC3-II/I, Beclin-1, p62, cleaved caspase-3, IκBα and NF-κB were measured by the western blotting. Results showed that CUR significantly decreased the cell apoptosis, the ROS generation and the inflammatory cytokine NF-κB activity in the HG-induced HUVECs versus the control, P<0.05. In addition, CUR significantly increased the expressions of LC3-II/I, Beclin-1, IκBα and Bax/Bcl-2 in the HG-induced HUVECs versus the control, P<0.05. Furthermore, the addition of autophagy inhibitor 3-MA impaired the autophagy, exacerbated the apoptotic death and increased the ROS and NF-κB levels in HUVECs under the high glucose condition, P<0.05. In brief, autophagy served a protective role in the HG-induced apoptosis in HUVECs and CUR alleviated apoptosis by promoting autophagy and inhibiting the ROS/NF-κB signaling pathway.

A Dual Inhibitor of DYRK1A and GSK3ß for ß-Cell Proliferation: Aminopyrazine Derivative GNF4877.

Loss of ß-cell mass and function can lead to insufficient insulin levels and ultimately to hyperglycemia and diabetes mellitus. The mainstream treatment approach involves regulation of insulin levels; however, approaches intended to increase ß-cell mass are less developed. Promoting ß-cell proliferation with low-molecular-weight inhibitors of dual-specificity tyrosine-regulated kinase 1A (DYRK1A) offers the potential to treat diabetes with oral therapies by restoring ß-cell mass, insulin content and glycemic control. GNF4877, a potent dual inhibitor of DYRK1A and glycogen synthase kinase 3ß (GSK3ß) was previously reported to induce primary human ß-cell proliferation in vitro and in vivo. Herein, we describe the lead optimization that lead to the identification of GNF4877 from an aminopyrazine hit identified in a phenotypic high-throughput screening campaign measuring ß-cell proliferation.

Wenxin Granule Ameliorates Hypoxia/Reoxygenation-Induced Oxidative Stress in Mitochondria via the PKC-δ/NOX2/ROS Pathway in H9c2 Cells.

Myocardial infarction and following reperfusion therapy-induced myocardial ischemia/reperfusion (I/R) injury have been recognized as an important subject of cardiovascular disease with high mortality. As the antiarrhythmic agent, Wenxin Granule (WXG) is widely used to arrhythmia and heart failure. In our pilot study, we found the antioxidative potential of WXG in the treatment of myocardial I/R. This study is aimed at investigating whether WXG could treat cardiomyocyte hypoxia/reoxygenation (H/R) injury by inhibiting oxidative stress in mitochondria. The H9c2 cardiomyocyte cell line was subject to H/R stimuli to mimic I/R injury in vitro. WXG was added to the culture medium 24 h before H/R exposing as pretreatment. Protein kinase C-δ (PKC-δ) inhibitor rottlerin or PKC-δ lentivirus vectors were conducted on H9c2 cells to downregulate or overexpress PKC-δ protein. Then, the cell viability, oxidative stress levels, intracellular and mitochondrial ROS levels, mitochondrial function, and apoptosis index were analyzed. In addition, PKC-δ protein expression in each group was verified by western blot analysis. Compared with the control group, the PKC-δ protein level was significantly increased in the H/R group, which was remarkably improved by WXG or rottlerin. PKC-δ lentivirus vector-mediated PKC-δ overexpression was not reduced by WXG. WXG significantly improved H/R-induced cell injury, lower levels of SOD and GSH/GSSG ratio, higher levels of MDA, intracellular and mitochondrial ROS content, mitochondrial membrane potential and ATP loss, mitochondrial permeability transition pore opening, NOX2 activation, cytochrome C release, Bax/Bcl-2 ratio and cleaved caspase-3 increasing, and cell apoptosis. Similar findings were obtained from rottlerin treatment. However, the protective effects of WXG were abolished by PKC-δ overexpression, indicating that PKC-δ was a potential target of WXG treatment. Our findings demonstrated a novel mechanism by which WXG attenuated oxidative stress and mitochondrial dysfunction of H9c2 cells induced by H/R stimulation via inhibitory regulation of PKC-δ/NOX2/ROS signaling.

Selective DYRK1A Inhibitor for the Treatment of Type 1 Diabetes: Discovery of 6-Azaindole Derivative GNF2133.

Autoimmune deficiency and destruction in either ß-cell mass or function can cause insufficient insulin levels and, as a result, hyperglycemia and diabetes. Thus, promoting ß-cell proliferation could be one approach toward diabetes intervention. In this report we describe the discovery of a potent and selective DYRK1A inhibitor GNF2133, which was identified through optimization of a 6-azaindole screening hit. In vitro, GNF2133 is able to proliferate both rodent and human ß-cells. In vivo, GNF2133 demonstrated significant dose-dependent glucose disposal capacity and insulin secretion in response to glucose-potentiated arginine-induced insulin secretion (GPAIS) challenge in rat insulin promoter and diphtheria toxin A (RIP-DTA) mice. The work described here provides new avenues to disease altering therapeutic interventions in the treatment of type 1 diabetes (T1D).

Pancreas-Specific Delivery of ß-Cell Proliferating Small Molecules.

Our research groups recently described a series of small-molecule inducers of ß-cell proliferation that could be used to increase ß-cell mass. To mitigate the risk of nonspecific proliferation of other cell types, we devised a delivery strategy built on the tissue specificity observed in the experimental ß-cell imaging agent (+)-dihydrotetrabenazine (DTBZ). The ß-cell proliferator agent aminopyrazine (AP) was covalently linked with (+)-DTBZ to afford conjugates that retain both the proliferation activity and binding affinity for vesicular monoamine transporter-2 (VMAT2). In vivo mouse tissue distribution studies of a prototypical AP-DTBZ conjugate showed 15-fold pancreas exposure over plasma. Tissue-to-plasma ratios in liver and kidneys were two- and five-fold, respectively. This work is the first demonstration of enhanced delivery of ß-cell-proliferating molecules to the pancreas by leveraging the intrinsic tissue specificity of a ß-cell imaging agent.

Inhibition of DYRK1A and GSK3B induces human ß-cell proliferation.

Insufficient pancreatic ß-cell mass or function results in diabetes mellitus. While significant progress has been made in regulating insulin secretion from ß-cells in diabetic patients, no pharmacological agents have been described that increase ß-cell replication in humans. Here we report aminopyrazine compounds that stimulate robust ß-cell proliferation in adult primary islets, most likely as a result of combined inhibition of DYRK1A and GSK3B. Aminopyrazine-treated human islets retain functionality in vitro and after transplantation into diabetic mice. Oral dosing of these compounds in diabetic mice induces ß-cell proliferation, increases ß-cell mass and insulin content, and improves glycaemic control. Biochemical, genetic and cell biology data point to Dyrk1a as the key molecular target. This study supports the feasibility of treating diabetes with an oral therapy to restore ß-cell mass, and highlights a tractable pathway for future drug discovery efforts.

Levels of brain natriuretic peptide are associated with peripheral arterial disease in subjects with type-2 diabetes mellitus.

BACKGROUND: The effects of brain natriuretic peptide (BNP) on the risk of cardiovascular disease and atherosclerosis have been studied. However, little information is available regarding peripheral arterial disease (PAD), particularly among subjects with type-2 diabetes mellitus (T2DM). The aim of our study was to assess the potential relationship between BNP levels and PAD among T2DM patients. METHODS: The study cohort was 507 T2DM outpatients in which BNP levels were measured. Cross-sectional associations between BNP levels (in tertiles) and PAD were examined. RESULTS: Compared withT2DM patients without PAD, BNP levels were markedly higher in patients with PAD (p = 0.001). Correlation analyses showed that the BNP level was negatively correlated with the ankle-brachial index (r = -0.453, p = 0.033). At a cutoff value of 78.2 pg/ml, the BNP level showed a sensitivity of 71.9%, a specificity of 68.1%, and a positive predictive value of 84.3% for a diagnosis of PAD. The area under the receiver-operating characteristic curve increased significantly if BNP levels were incorporated into a predictive model of the potential risk factors for PAD (0.85 vs 0.81, p = 0.029). CONCLUSIONS: BNP is a potential and promising biomarker for PAD screening in T2DM patients.

Low Serum retinol-binding protein-4 levels in acute exacerbations of chronic obstructive pulmonary disease at intensive care unit admission is a predictor of mortality in elderly patients.

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are thought to be associated with increased mortality in elderly patients. Low retinol-binding protein-4 (RBP4) is associated with a high risk of respiratory infections in the general population. Therefore, we hypothesized that low RBP4 levels are associated with an increased risk of AECOPD and can be used as a biomarker for AECOPD in elderly patients. METHODS: Enzyme-linked immunosorbent assays were used to assess RBP4 levels in elderly with AECOPD within the first 24 hours after intensive care unit admission. Forty-six elderly patients with stable COPD in outpatient clinics and 50 healthy elderly persons who had physical examinations as outpatients were controls. RESULTS: In AECOPD patients, RBP4 levels were lower than those in stable COPD patients and healthy controls (59.7 vs 91.2 and 113.6 mg/L, p < 0.001). RBP4 levels were decreased by 30.6% in non-survivors compared with survivors (51.5 vs 74.2 mg/L, p < 0.001). A higher Acute Physiology and Chronic Health Enquiry II (APACHE II) score and Simplified Acute Physiology score (SAPS II) were associated with lower RBP4 levels (r = -0.692, p = 0.024 and r = -0.670, p = 0.015, respectively). RBP4 was positively correlated with creatinine and body mass index, and negatively correlated with C-reactive protein and Global Initiative for Chronic Obstructive Lung Disease stage. Multivariate logistic regression showed that RBP4 was an independent mortality predictor of AECOPD (odds ratio: 0.926, p = 0.007). Analysis of the area under the receiver operating characteristic (AUC) curve showed that RBP4 showed good discrimination (AUC: 0.88; 95% confidence interval: 0.78-0.94; p = 0.008) in predicting mortality. RBP4 improved the prognostic accuracy of mortality for the APACHE II and SAPS II scores. CONCLUSIONS: Serum RBP4 levels are significantly reduced in elderly AECOPD patients. RBP4 might be a good predictive biomarker for mortality in elderly AECOPD patients in the intensive care unit.

Serum galectin-3: a risk factor for vascular complications in type 2 diabetes mellitus.

BACKGROUND: Plasma galectin-3, a mediator of fibrogenesis and inflammation, its potential to associate with type 2 diabetes (T2DM) is poorly investigated. Here, we explored its interaction with the serum galectin-3 and vascular complications. METHODS: We conducted a population-based cross-sectional survey in Zhejiang, China involving 165 men and 119 women (age range, 43 - 84 years), investigating the relationship between serum galectin-3 and vascular disease in patients with T2DM. RESULTS: Serum galectin-3 was higher in subjects with T2DM than that in control participants (27.4 vs. 17.6 ng/ml, P < 0.001). Compared with subjects with galectin-3 values in the lowest quartile, those with values in the highest quartile had an increased likelihood of vascular complications (4th quartile odds ratio (OR) 2.52, 95% confidence interval (CI), 1.25 - 4.07). Increased risk of micro- or macrovascular complications correlated with serum galectin-3 concentration (ORs 11.4 and 8.5, respectively). An increased number of vascular complications was associated with high serum galectin-3 levels (P < 0.05). Patients with serum galectin-3 levels > 25 ng/ml had an elevated risk of diabetes relative to patients with levels < 10 ng/ml (OR for any vascular complication 2.64, for heart failure 3.97, for nephropathy 4.09, for peripheral arterial disease (PAD) 4.18; all P < 0.05). Complication risk was higher in patients with neurogenic, stroke, or retinopathy complications, but this difference was not significant after risk factor adjustment. Serum galectin-3 levels correlated with diabetes duration, C-reactive protein (CRP) levels, and albuminuria. CONCLUSION: High galectin-3 values were associated with increased odds of developing heart failure, nephropathy, and peripheral arterial disease in patients with T2DM.

Curcumin improves expression of SCF/c-kit through attenuating oxidative stress and NF-κB activation in gastric tissues of diabetic gastroparesis rats.

BACKGROUND: Diabetes mellitus is associated with many kinds of complications. Recent studies have shown that oxidative stress and inflammatory reactions have critical roles in the pathogenesis of diabetic gastroparesis. Curcumin is known to have antioxidant and anti-inflammatory properties. In the present study, we investigated the effect of curcumin on diabetic gastric motility in a Sprague Dawley rat model of type 1 diabetes mellitus. METHODS: Male SD rats were divided into a control group, a control group receiving curcumin, a diabetic group, and a diabetic group receiving curcumin. Diabetes was induced by intraperitoneal injection of streptozotocin. Curcumin (150 mg/kg) was given intragastrically for 6 weeks, and blood glucose levels and body weights were measured. Stomachs were excised for analysis of gastric emptying rates, and levels of oxidative stress. NF-κB, I-κB, and stem cell factor (SCF)/c-kit protein levels were assessed by western blot analysis, while the apoptosis of interstitial cells of Cajal (ICCs) was assessed by TUNEL staining. RESULTS: Curcumin-treated diabetic rats showed significantly improved gastric emptying rates [(59.4 ± 7.5)%] compared with diabetic rats [(44.3 ± 5.7)%], as well as decreased levels of MDA [21.4 ± 1.8 (nmol/mg) vs 27.9 ± 2.1 (nmol/mg)], and increased SOD activity [126.2 ± 8.8 (units/mg) vs 107.9 ± 7.5 (units/mg)]. On the other hand, the gastric emptying level in the control group was not significantly different from that in the control group receiving curcumin treatment. In addition, curcumin-treated diabetic rats showed significantly increased levels of SCF/c-kit protein in stomach tissues, inhibited I-κB degradation and NF-κB activation, and reduced ICC apoptosis index [(26.2 ± 4.1)% vs (47.5 ± 6.2)%], compared with the diabetic group. CONCLUSION: Curcumin treatment improved gastric emptying by blocking the production of oxidative stress, abolishing NF-κB signal transduction and enhancing expression of SCF/c-kit in rats with diabetic gastroparesis.

Small-molecule inducer of ß cell proliferation identified by high-throughput screening.

The identification of factors that promote ß cell proliferation could ultimately move type 1 diabetes treatment away from insulin injection therapy and toward a cure. We have performed high-throughput, cell-based screens using rodent ß cell lines to identify molecules that induce proliferation of ß cells. Herein we report the discovery and characterization of WS6, a novel small molecule that promotes ß cell proliferation in rodent and human primary islets. In the RIP-DTA mouse model of ß cell ablation, WS6 normalized blood glucose and induced concomitant increases in ß cell proliferation and ß cell number. Affinity pulldown and kinase profiling studies implicate Erb3 binding protein-1 and the IκB kinase pathway in the mechanism of action of WS6.

Polymorphism of rs1836882 in NOX4 gene modifies associations between dietary caloric intake and ROS levels in peripheral blood mononuclear cells.

Excessive caloric intake is a contributing risk factor for human metabolic disorders. Caloric restriction may prolong a person's life by lowering the incidence of deadly diseases. Reactive oxygen species (ROS) in peripheral blood mononuclear cells (PBMC) have been associated with the biochemical basis of the relationship between caloric intake and pathophysiologic processes. Polymorphisms associated with ROS generation genes are being increasingly implicated in inter-individual responses to daily caloric intake alterations. In the current study, a single nucleotide polymorphism, rs1836882, in the nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) gene's promoter region was found to modulate associations between dietary caloric intake and ROS levels in PBMC. Based on rs1836882, 656 Chinese Han participants were classified into CC, CT and TT genotypes. ROS levels in PBMC were significantly higher in the CC or CT genotypes compared with the TT genotype with the same increases in daily caloric intake. Using an electrophoretic mobility shift assay, NOX4 promoter region with rs1836882 (T) was observed to have a higher affinity for hepatocyte nuclear factor gamma (HNF3γ) protein than rs1836882 (C). HNF3γ protein over-expression decreased NOX4 gene transcriptional activity in the TT genotype more than in the CC genotype (5.68% vs. 2.12%, P<0.05) in a dual luciferase reporter assay. By silencing the NOX4 gene using small interfering RNA or over-expressing HNF3γ using an expression plasmid, serum from high dietary caloric intake participants decreased ROS levels in PBMC of the TT genotype more than in the CC or CT genotype via HNF3γ down-regulating the NOX4 gene expression signaling pathway. This is the first study to report on the functions of phenotypes of rs1836882 in the NOX4 gene, and it suggests rs1836882 as a candidate gene for interpreting inter-individual ROS levels differences in PBMC induced by alterations in daily caloric intake.

[The relationship between sleep quality and glucose level, diabetic complications in elderly type 2 diabetes mellitus].

OBJECTIVE: To explore the relationship between sleep quality and glucose level, diabetic complications in elderly type 2 diabetes mellitus. METHODS: A total of 130 hospitalized elderly type 2 diabetes in our hospital were included in the study. Questionnaires and other related clinical data were collected within one week after admission. Patients were divided into two groups: poor-sleeper group and good-sleeper group according to Pittsburgh Sleep Quality Index (PSQI). RESULTS: Sixty percent (78/130) of these patients were poor sleepers. The following parameters differed in the two groups: the duration of diabetes [(7.9 ± 1.8) years vs (7.2 ± 1.5) years, t = 2.318], systolic blood pressure [(148 ± 30) mm Hg (1 mm Hg = 0.133 kPa) vs (138 ± 23) mm Hg, t = 2.037], fasting plasma glucose (FPG) [(10.7 ± 2.2) mmol/L vs (9.8 ± 1.9) mmol/L, t = 2.410], hemoglobin A1c (HbA1c) [(8.6 ± 2.2)% vs (7.8 ± 2.1)%, t = 2.068], high-sensitive C-reactive protein (hs-CRP) [(5.27 ± 2.34) mg/L vs (4.44 ± 1.76) mg/L, t = 2.179], ratio of diabetic complications (61% vs 32%, χ(2) = 4.257), percentage of depression (20% vs 8%, χ(2) = 3.722), score of life quality [(98 ± 19) scores vs (89 ± 13) scores, t = 2.980], and proportion of patients treated with insulin (32% vs 12%, χ(2) = 4.489). All the above parameters were significantly higher in poor-sleeper group than the good-sleeper group (all P value < 0.05). Multiple correlation analysis showed that the factors affecting sleep quality were FPG, HbA1c, duration of diabetes, diabetic complications, depression, life quality and insulin application (r = 0.213, 0.257, 0.223, 0.335, 0.422, 0.3451, 0.231, respectively; all P value < 0.05). By multivariate logistic regression analysis, the followings were found: FPG (ß = 1.29, P < 0.05) and PSQI (ß = 1.07, P < 0.05) were found to be correlated with HbA1c. With increasing of PSQI, FPG, HbA1c, diabetic complications and life quality were changed significantly (all P value < 0.05). The independent risk factors of diabetic complications were duration of diabetes (OR = 1.32, 95%CI 1.01 - 2.01), HbA1c (OR = 2.01, 95%CI 1.63 - 2.67), hs-CRP (OR = 1.12, 95%CI 1.08 - 1.21) and PSQI (OR = 1.71, 95%CI 1.58 - 2.02). CONCLUSIONS: Elderly type 2 diabetes mellitus are usually poor sleepers. Sleep quality probably affects blood glucose regulation, and is closely correlated with the occurrence of complications. In addition, poor sleep quality results in poor life quality.

Predictive value of serum cholinesterase for the prognosis of aged patients with systemic inflammatory response syndrome.

BACKGROUND: Some studies found that cholinesterase (ChE) can be an independent risk factor for patients with multiple organ dysfunction syndrome. To assess aged patients with systemic inflammatory response syndrome (SIRS) early and predict their prognosis, the predictive value of ChE for the prognosis of aged patients with SIRS was analyzed. METHODS: From September 2009 to September 2010, all aged patients with SIRS in the ICU of the Second Affiliated Hospital of Zhejiang University School of Medicine were retrospectively analyzed if they met inclusion criteria: patients aged ≥ 65 years and met American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference criteria for SIRS. Serum ChE, albumin, D-dimer, lactic acid and C-reactive protein (CRP) were measured, and the Acute Physiology and Chronic Health Evaluation (APACHE) II and Glasgow Coma Scale (GCS) scores were evaluated within the first 24 hours in the ICU. Fisher's exact test was used for comparison of the primary disease between the deceased group and surviving group. For comparison of study variables between the two groups, the Student's t test or Mann-Whitney U test was used. Multivariate significance was tested with binary Logistic regression analysis. RESULTS: The clinical data of 124 aged patients with SIRS were collected and analyzed. Sixty-six patients (46 male, 20 female, mean age (78.70 ± 8.08) years) who died were included in the deceased group and 58 patients (34 male, 24 female, mean age (76.02 ± 6.57) years) who survived were included in the surviving group. There were no significant differences in age, gender, APACHE II score and GCS score between the deceased group and surviving group (all P > 0.05), but there were significant differences in lactic acid (P = 0.011), D-dimer (P = 0.011), albumin (P = 0.007), CRP (P = 0.008), and ChE (P < 0.0001). The correlation analysis showed that the APACHE II score and CRP were not correlated with ChE (both P < 0.05). D-dimer and albumin were correlated with ChE (Spearman's rho correlation coefficients were -0.206 and 0.324, the corresponding P values were 0.022 and < 0.0001). Multiple Logistic regression analysis showed that age, gender, lactic acid, D-dimer, albumin, CRP, APACHE II score, and GCS score were not independent risk factors for prognosis of aged patients with SIRS, but that ChE was (P < 0.0001). The receiver operating characteristic curve of ChE had an area under the curve of 0.797 (standard error = 0.04; P < 0.0001), and a ChE of 103.00 U/L was the cut-off value with sensitivity = 0.793, specificity = 0.742. CONCLUSION: Serum ChE might be a predictive marker for the prognosis of aged patients with SIRS, with low serum ChE levels indicating poor prognosis.

[Relationship between plasma total homocysteine and mild cognitive impairment in senile patients with type 2 diabetes].

OBJECTIVE: To explore the relationship between fasting plasma level of total homocysteine (tHcy) and mild cognitive impairment in senile patients with type 2 diabetes mellitus. METHODS: A total of 88 senile type 2 diabetics with mild cognitive impairment treated at our hospital from July 2008 to November 2010 were recruited into the MCI group while 52 senile type 2 diabetics into the DNC group. And the control group was composed of 36 healthy elders. The parameters of tHcy, total glyceride (TG), total cholesterol (TC), low density lipoprotein-C (LDL-C), high density lipoprotein-C (HDL-C), creatinine (Cr), hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), 2 h plasma glucose (2 hPG), fasting insulin (FINS), homeostasis model of insulin resistance (HOMA-IR), folic acid (FA) and vitamin B(12) (VitB(12)) were detected. RESULTS: The patients had a higher level of tHcy in the MCI group than those in the NCM and control groups [(11.3 ± 1.8) vs (9.8 ± 1.5) and (8.1 ± 1.1) µmol/L; P < 0.01]. ROC curve showed that tHcy level had some value of predicting the occurrence of mild cognitive impairment in senile patients with type 2 diabetes mellitus (AUC 0.825, 95%CI 0.758-0.893, P < 0.01). Logistic regression analysis showed that tHcy, SBP, HbA1c, 2 h PG, FINS, LDL-C, HOMA-IR, FA and VitB(12) [OR value: 3.64, 1.68, 1.10, 1.05, 0.81, 1.42, 0.83, 0.74, 0.86 (P < 0.05 or 0.01)] were independent risk factors of mild cognitive impairment in senile diabetic patients. CONCLUSION: Such factors as tHcy, SBP, HbA1c, FPG, 2 hPG, FINS, LDL-C, HOMA-IR, FA and VitB(12) induce senile patients with type 2 diabetes mellitus to suffer mild cognitive impairment. But tHcy level may play an important role in senile diabetic patients with mild cognitive impairment.

Small molecule antagonists in distinct binding modes inhibit drug-resistant mutant of smoothened.

Several small molecule antagonists for Smoothened (Smo) have been developed, and achieved promising preclinical efficacy in cancers that are dependent on Hedgehog (Hh) signaling. However, in a recent clinical study, a drug-resistant D473H SMO mutant was identified that is thought to be responsible for cancer relapse in a patient with medulloblastoma. Here, we report two Smo antagonists that bind to distinct sites, as compared to known antagonists and agonists, and inhibit both wild-type and mutant Smo. These findings provide an insight of the ligand-binding sites of Smo and a basis for the development of potential therapeutics for tumors with drug-resistant Smo mutations.

Neferine inhibits angiotensin II-stimulated proliferation in vascular smooth muscle cells through heme oxygenase-1.

AIM: To explore the effect of neferine on angiotensin II (Ang II)-induced vascular smooth muscle cell (VSMC) proliferation. METHODS: Human umbilical vein smooth muscle cells (HUVSMCs) were used. Cell proliferation was determined by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry analysis. Heme oxygenase (HO)-1 protein expression was tested by Western blot analysis. Extracellular signal-regulated protein kinase 1/2 (ERK1/2) activation was determined by using immunoblotting. RESULTS: Pre-incubation of HUVSMCs with neferine (0.1, 0.5, 1.0, and 5.0 micromol/L) significantly inhibited Ang II-induced cell proliferation in a concentration-dependent manner and neferine 5.0 micromol/L increased HO-1 expression by 259% compared with control. The antiproliferative effect of neferine was significantly attenuated by coapplication of zinc protoporphyrin IX (ZnPP IX, an HO-1 inhibitor) with neferine. Ang II-enhanced ERK1/2 phosphorylation was markedly reversed by neferine. By inhibiting HO-1 activity with ZnPP IX, the inhibitive effect of neferine on ERK1/2 phosphorylation was significantly attenuated. Cobalt-protoporphyrin (CoPP), an HO-1 inducer, significantly decreased Ang II-induced ERK1/2 phosphorylation and inhibited Ang II-induced cell proliferation. The ERK1/2 pathway inhibitor PD98059 significantly blocked Ang II-enhanced ERK1/2 phosphorylation and inhibited cell proliferation. CONCLUSION: These findings suggest that neferine can inhibit Ang II-induced HUVSMC proliferation by upregulating HO-1, leading to the at least partial downregulation of ERK1/2 phosphorylation.

Proteomic screen for multiprotein complexes in synaptic plasma membrane from rat hippocampus by blue native gel electrophoresis and tandem mass spectrometry.

Neuronal synapses are specialized sites for information exchange between neurons. Many diseases, such as addiction and mood disorders, likely result from altered expression of synaptic proteins, or altered formation of synaptic complexes involved in neurotransmission or neuroplasticity. A detailed description of native multiprotein complexes in synaptic plasma membranes (PM) is therefore essential for understanding biological mechanisms and disease processes. For the first time in this study, two-dimensional Blue Native/SDS-PAGE electrophoresis, combined with tandem mass spectrometry, was used to screen multiprotein complexes in synaptic plasma membranes from rat hippocampus. As a result, 514 unique proteins were identified, of which 36% were integral membrane proteins. In addition, 19 potentially novel and known heterooligomeric multiprotein complexes were found, such as the SNARE and ATPase complexes. A potentially novel protein complex, involving syntaxin, synapsin I and Na+/K+ ATPase alpha-1, was further confirmed by co-immunoprecipitation and immunofluorescence staining. As demonstrated here, Blue Native-PAGE is a powerful tool for the separation of hydrophobic membrane proteins. The combination of Blue Native-PAGE and mass spectrometry could systematically identify multiprotein complexes.

Evaluation of two cell surface modification methods for proteomic analysis of plasma membrane from isolated mouse hepatocytes.

The hepatocyte is a highly polarized cell with a heterogeneous distribution of plasma-membrane (PM) proteins. To reduce the complexity of the proteome of liver tissue and give a comprehensive profile of hepatocyte PM, two PM purification methods based on cell surface modification, named the biotin-avidin (BA) and cationic silica-polyanion (CSP) strategies were evaluated and compared with the traditional cell fractionation method to prepare highly enriched PM from freshly isolated C57 mouse hepatocytes. Employing different principles for PM modification, both methods were effective in the isolation of general and purified PM fraction. The CSP strategy showed better yield for the PM purification from freshly isolated hepatocytes. 189 non-redundant proteins were identified, including 49 from the BA method and 185 from CSP strategy. Many known and novel PM-associated proteins were also found. Our evaluation here should give implications for PM preparation from other freshly isolated tissue-derived cells. The hepatocyte PM proteins identified here should be taken as a references for the PM-related functional and diseases research.