On the open problem related to rank equalities for the sum of finitely many idempotent matrices and its applications.

Tian and Styan have shown many rank equalities for the sum of two and three idempotent matrices and pointed out that rank equalities for the sum P1 + ⋯+P k with P1,…, P k be idempotent (k > 3) are still open. In this paper, by using block Gaussian elimination, we obtained rank equalities for the sum of finitely many idempotent matrices and then solved the open problem mentioned above. Extensions to scalar-potent matrices and some related matrices are also included.

Endoplasmic reticulum stress-mediated aldosterone-induced apoptosis in vascular endothelial cells.

The aim of this study was to examine the effects of endoplasmic reticulum (ER) stress on aldosterone (Aldo)-induced apoptosis of endothelial cells. Glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP, a hallmark of ER-associated apoptosis) were used to evaluate ER stress. Western blotting and real-time PCR were used to analyze indicators of ER molecule. Apoptosis was detected by annexin V/propidium iodide staining and flow cytometry. Human umbilical vein endothelial cells (HUVECs) were stimulated with different concentrations of Aldo for different durations. Aldo promoted apoptosis of HUVECs and induced ER stress, as evidenced by increased expression of GRP78 and CHOP. siRNA knockdown of CHOP attenuated Aldo-mediated apoptosis. These results indicate that ER stress may be involved in Aldo-induced apoptosis of HUVECs.

Icariin ameliorates glycolytic dysfunction in Alzheimer's disease models by activating the Wnt/ß-catenin signaling pathway.

It was reported that the Wnt/ß-catenin pathway is involved in the regulation of aerobic glycolysis and that brain glycolytic dysfunction results in the development of Alzheimer's disease (AD). Icariin (ICA), an active component extracted from Epimedii Folium, has been reported to produce neuroprotective effects in multiple models of AD, but its underlying mechanism remains to be fully described. We aimed to investigate the protective effects of ICA on animal and cell models of AD and confirm whether the Wnt/ß-catenin pathway has functions in the neuroprotective function of ICA. The 3 × Tg-AD mice were treated with ICA. HT22 cells, the Aß25-35 peptide and Dickkopf-1 (DKK1) agent (a specific inhibitor of the Wnt/ß-catenin pathway) were used to further explore the underlying mechanism of ICA that produces anti-AD effects. Behavioral examination, western blotting assay, staining analysis, biochemical test, and lactate dehydrogenase (LDH) assays were applied. We first demonstrated that ICA significantly improved cognitive function and autonomous behavior, reduced neuronal damage, and reversed the protein levels and activities of glycolytic key enzymes, and expression of protein molecules of the canonical Wnt signaling pathway, in 3 × Tg-AD mice back to wild-type levels. Next, we further found that ICA increased cell viability and effectively improved the dysfunctional glycolysis in HT22 cells injured by Aß25-35. However, when canonical Wnt signaling was inhibited by DKK1, the above effects of ICA on glycolysis were abolished. In summary, ICA exerts neuroprotective effects in 3 × Tg-AD animals and AD cellular models by enhancing the function of glycolysis through activation of the Wnt/ß-catenin pathway.

Icariin ameliorates memory deficits through regulating brain insulin signaling and glucose transporters in 3×Tg-AD mice.

Icariin, a major prenylated flavonoid found in Epimedium spp., is a bioactive constituent of Herba Epimedii and has been shown to exert neuroprotective effects in experimental models of Alzheimer's disease. In this study, we investigated the neuroprotective mechanism of icariin in an APP/PS1/Tau triple-transgenic mouse model of Alzheimer's disease. We performed behavioral tests, pathological examination, and western blot assay, and found that memory deficits of the model mice were obviously improved, neuronal and synaptic damage in the cerebral cortex was substantially mitigated, and amyloid-ß accumulation and tau hyperphosphorylation were considerably reduced after 5 months of intragastric administration of icariin at a dose of 60 mg/kg body weight per day. Furthermore, deficits of proteins in the insulin signaling pathway and their phosphorylation levels were significantly reversed, including the insulin receptor, insulin receptor substrate 1, phosphatidylinositol-3-kinase, protein kinase B, and glycogen synthase kinase 3ß, and the levels of glucose transporter 1 and 3 were markedly increased. These findings suggest that icariin can improve learning and memory impairments in the mouse model of Alzheimer's disease by regulating brain insulin signaling and glucose transporters, which lays the foundation for potential clinical application of icariin in the prevention and treatment of Alzheimer's disease.

Suppression of hnRNP A1 binding to HK1 RNA leads to glycolytic dysfunction in Alzheimer's disease models.

Objective: To investigate the mechanism of RNA-binding protein hnRNP A1 in mouse hippocampal neurons (HT22) on glycolysis. Methods: RIP and CLIP-qPCR were performed by HT22 in vitro to observe the mechanism of hnRNP A1 regulating the expression of key proteins in glycolysis. The RNA binding domain of hnRNP A1 protein in HT22 was inhibited by VPC-80051, and the effect of hnRNP A1 on glycolysis of HT22 was observed. Lentivirus overexpression of hnRNP A1 was used to observe the effect of overexpression of hnRNP A1 on glycolysis of Aß25-35-injured HT22. The expression of hnRNP A1 in brain tissues of wild-type mice and triple-transgenic (APP/PS1/Tau) AD mice at different ages was studied by Western blot assay. Results: The results of RIP experiment showed that hnRNP A1 and HK1 mRNA were significantly bound. The results of CLIP-qPCR showed that hnRNP A1 directly bound to the 2605-2821 region of HK1 mRNA. hnRNP A1 inhibitor can down-regulate the expression of HK1 mRNA and HK1 protein in HT22 cells. Overexpression of hnRNP A1 can significantly reduce the toxic effect of Aß25-35 on neurons via the hnRNP A1/HK1/ pyruvate pathway. In addition, inhibition of hnRNP A1 binding to amyloid precursor protein (APP) RNA was found to increase Aß expression, while Aß25-35 also down-regulated hnRNP A1 expression by enhancing phosphorylation of p38 MAPK in HT22. They interact to form bidirectional regulation, further down-regulating the expression of hnRNP A1, and ultimately aggravating glycolytic dysfunction. Protein immunoblotting showed that hnRNP A1 decreased with age in mouse brain tissue, and the decrease was greater in AD mice, suggesting that the decrease of hnRNP A1 may be a predisposed factor in the pathogenesis of AD.

Glycogen Synthase Kinase 3ß Inhibitor (2'Z,3'E)-6-Bromo-indirubin- 3'-Oxime Enhances Drug Resistance to 5-Fluorouracil Chemotherapy in Colon Cancer Cells.

OBJECTIVE: To explore the effects and mechanism of glycogen synthase kinase 3ß (GSK-3ß) inhibitor (2'Z,3'E)-6-bromo-indirubin-3'-oxime (BIO) on drug resistance in colon cancer cells. METHODS: The colon cancer SW480 and SW620 cells were treated with BIO, 5-fluorouracil (5-FU) and BIO/5-FU, separately. Cell cycle distribution, apoptosis level and efflux ability of rhodamine 123 (Rh123) were detected by flow cytometry. The protein expressions of P-glycoprotein (P-gp), multidrug resistance protein 2 (MRP2), thymidylate synthase (TS), ß-catenin, E2F-1 and Bcl-2 were detected by Western blot. ß-catenin and P-gp were stained with double immunofluorescence and observed under a confocal microscope. RESULTS: BIO up-regulated ß-catenin, P-gp, MRP2 and TS, enhanced the efflux ability of Rh123, decreased Bcl-2 protein and gave the opposite effect to E2F-1 protein in SW480 and SW620 cells. Furthermore, BIO significantly inhibited cell apoptosis, increased S and G(2)/M phase cells, and reduced the cell apoptosis induced by 5-FU in SW480 cells, whereas the effects were slight or not obvious in SW620 cells. CONCLUSION: GSK-3ß was involved in drug resistance regulation, and activation of ß-catenin and inhibition of E2F-1 may be the most responsible for the enhancement of 5-FU chemotherapy resistance induced by GSK-3ß inhibitor BIO in colon cancer.

[The study of salivary pepsin content and laryngopharyngeal reflux scale in 91 asymptomatic volunteers].

OBJECTIVES: To investigate the content of pepsin in salivary, and to assess the laryngophargeal lesions based on the reflux founding score (RFS) scale in asymptomatic volunteers, in order to provide a reference for the diagnosis of laryngopharyngeal reflux. METHODS: A total of 91 asymptomatic subjects were recruited in this study. Participants provided a fasting saliva specimen for pepsin measurement using enzyme-linked immunoadsorbent assay, completed the reflux symptom index (RSI) assessment and underwent laryngostroboscopic examination using a rigid endoscope. Their RFS were graded according to the laryngeal findings. RESULTS: The median concentration of pepsin in 91 asymptomatic volunteers was 55.5 µg/L (range 3.53-191.64 µg/L). The mean individuals RSI was 2.24±2.34, and the mean individuals RFS was 5.78±1.74. CONCLUSIONS: Our data demonstrate that certain concentration of pepsin was detected and showed a higher RFS score in asymptomatic volunteers.

[An early warning method of cucumber downy mildew in solar greenhouse based on canopy temperature and humidity modeling].

The greenhouse environmental parameters can be used to establish greenhouse nirco-climate model, which can combine with disease model for early warning, with aim of ecological controlling diseases to reduce pesticide usage, and protecting greenhouse ecological environment to ensure the agricultural product quality safety. Greenhouse canopy leaf temperature and air relative humidity, models were established using energy balance and moisture balance principle inside the greenhouse. The leaf temperature model considered radiation heat transfer between the greenhouse crops, wall, soil and cover, plus the heat exchange caused by indoor net radiation and crop transpiration. Furthermore, the water dynamic balance in the greenhouse including leaf transpiration, soil evaporation, cover and leaf water vapor condensation, was considered to develop a relative humidity model. The primary infection and latent period warning models for cucumber downy mildew (Pseudoperonospora cubensis) were validated using the results of the leaf temperature and relative humidity model, and then the estimated disease occurrence date of cucumber downy mildew was compared with actual disease occurrence date of field observation. Finally, the results were verified by the measured temperature and humidity data of September and October, 2014. The results showed that the root mean square deviations (RMSDs) of the measured and estimated leaf temperature were 0.016 and 0.024 °C, and the RMSDs of the measured and estimated air relative humidity were 0.15% and 0.13%, respectively. Combining the result of estimated temperature and humidity models, a cucumber disease early warning system was established to forecast the date of disease occurrence, which met with the real date. Thus, this work could provide the micro-environment data for the early warning system of cucumber diseases in solar greenhouses.