Functional conservation of the glycosyltransferase gene GT47A in the monocot rice

Glucuronoarabinoxylan is the major hemicellulose in grass cell walls, yet the mechanism of xylan synthesis in monocot plants is still unclear. Unraveling the genes involved in the biosynthesis of xylan in rice will be very important for the utilization of rice straw as a source of bioenergy in the future. In this report, we investigated the functional role of a rice gene homologous to Arabidopsis IRREGULAR XYLEM10 (IRX10), belonging to the glycosyl transferase (GT) gene family 47 (GT47), in the biosynthesis of xylan. The protein sequence of OsGT47A from rice exhibits a 93.49 % similarity to IRX10, which is involved in the biosynthesis of glucuronoxylan in Arabidopsis. Phylogenetic analysis of the GT47 glycosyl transferase family in the rice genome revealed that OsGT47A is a closely related homolog of IRX10 and IRX10L. Expression pattern analysis showed that the OsGT47A gene is highly expressed in the rice stem. Overexpression of OsGT47A in the irx10 irx10L double mutant rescued the plant growth phenotype and restored secondary wall thickness. Analysis of monosaccharides indicated that the rescued plants had levels of xylose identical to those of the wild type plants, and the fluorescence signals were restored in the complementation plants by xylan immunolocalization. The OsGT47A complementation under the native promoter of Arabidopsis IRX10L (ProIRX10L) partially rescued the double mutant, indicating that OsGT47A is functionally equivalent to IRX10L. Together, these results suggest that the IRX10 homolog OsGT47A exhibits functional conservation and is most likely involved in xylan synthesis in rice.     

Progesterone Attenuates Aquaporin-4 Expression in an Astrocyte Model of Ischemia/Reperfusion

Previous studies have suggested that progesterone may be involved in neuroprotection by preventing brain edema. In this study, we assessed the effects of progesterone on aquaporin-4 (AQP4) expression in an ischemia/reperfusion model of cultured rat astrocytes, and further explored the possible role of the protein kinase C (PKC) pathway in this course. We evaluate primary culture astrocytes exposed to 4 h oxygen–glucose deprivation (OGD) followed by 24 h reperfusion (OGD4h/R24h) as a means of simulating cortex ischemia and reperfusion, and test the effect of progesterone on AQP4 expression in response to OGD4h/R24h. Besides, the cell viability was assessed by MTT reduction and lactate dehydrogenase release assay, accompanied by cell morphology survey. At a concentration of 1 and 2 μM, progesterone significantly attenuated AQP4 at the level of both protein and mRNA and ameliorated the cell viability of astrocytes from OGD/reperfusion injury. Moreover, this effect was blocked by the PKC inhibitor Ro31-8220, which was employed before the OGD. These results indicate that progesterone exerts the protective effects and attenuates AQP4 expression in an astrocyte model of ischemia/reperfusion depending on the PKC signal pathway.     

Mutations in EMP2 Cause Childhood-Onset Nephrotic Syndrome

Nephrotic syndrome (NS) is a genetically heterogeneous group of diseases that are divided into steroid-sensitive NS (SSNS) and steroid-resistant NS (SRNS). SRNS inevitably leads to end-stage kidney disease, and no curative treatment is available. To date, mutations in more than 24 genes have been described in Mendelian forms of SRNS; however, no Mendelian form of SSNS has been described. To identify a genetic form of SSNS, we performed homozygosity mapping, whole-exome sequencing, and multiplex PCR followed by next-generation sequencing. We thereby detected biallelic mutations in EMP2 (epithelial membrane protein 2) in four individuals from three unrelated families affected by SRNS or SSNS. We showed that EMP2 exclusively localized to glomeruli in the kidney. Knockdown of emp2 in zebrafish resulted in pericardial effusion, supporting the pathogenic role of mutated EMP2 in human NS. At the cellular level, we showed that knockdown of EMP2 in podocytes and endothelial cells resulted in an increased amount of CAVEOLIN-1 and decreased cell proliferation. Our data therefore identify EMP2 mutations as causing a recessive Mendelian form of SSNS.     

PPARα agonist fenofibrate protects the kidney from hypertensive injury in spontaneously hypertensive rats via inhibition of oxidative stress and MAPK activity

Oxidative stress has been shown to play an important role in the development of hypertensive renal injury. Peroxisome proliferator-activated receptors α (PPARα) has antioxidant effect. In this study, we demonstrated that fenofibrate significantly reduced proteinuria, inflammatory cell recruitment and extracellular matrix (ECM) proteins deposition in the kidney of SHRs without apparent effect on blood pressure. To investigate the mechanisms involved, we found that fenofibrate treatment markedly reduced oxidative stress accompanied by reduced activity of renal NAD(P)H oxidase, increased activity of Cu/Zn SOD, and decreased phosphorylation of p38MAPK and JNK in the kidney of SHRs.Taken together, fenofibrate treatment can protect against hypertensive renal injury without affecting blood pressure by inhibiting inflammation and fibrosis via suppression of oxidative stress and MAPK activity.     

Proteomic analysis for the assessment of different lots of fetal bovine serum as a raw material for cell culture. Part IV. Application of proteomics to the manufacture of biological drugs

Fetal bovine serum (FBS) is the most widely used growth supplement for cell cultures, primarily because of its high levels of growth stimulatory factors and low levels of growth inhibitory factors. Maintaining successful and consistent cell fermentations can be difficult, as FBS is a complex natural product and may vary from lot to lot even from a single manufacturer. The quality and concentration of both bulk and specific proteins can affect cell growth. Quality control tools for FBS are relatively primitive and expensive given the complexity of the sample and the large amounts of FBS used. We undertook this study to examine whether proteomics could be used as a tool to analyze the variability of different fermentation processes. We hypothesized that inconsistent cell growth in fermentations could be due to the quality of FBS and that different lots of FBS had varying concentrations of proteins such as growth stimulatory factors, growth inhibitory factors, and/or other proteins that may correlate with cellular growth rate. To investigate whether this was the case, we grew three batches of adult retinal pigment epithelial cells (ARPE-19) using three different lots of fetal bovine serum (FBS-Ia, FBS-Ib, and FBS-II). We found that the growth rate of the culture was significantly and consistently higher in the FBS-II lot. To determine why the other lots promoted different growth properties, we used proteomic techniques to analyze the protein composition of the three lots. We then performed a time course study to monitor specific changes in individual proteins in the fermentation medium. The amount of several extracellular matrix and structural proteins, which are indicators of cell growth, increased over time. Alternatively, components supplied by the FBS addition, such as nutritional-related and cell-spreading-related proteins, decreased over time.     

Evaluation of polymorphisms in microRNA‐binding sites and pancreatic cancer risk in Chinese population

As promising biomarkers and therapy targets, microRNAs (miRNAs) are involved in various physiological and tumorigenic processes. Genetic variants in miRNA‐binding sites can lead to dysfunction of miRNAs and contribute to disease. However, systematic investigation of the miRNA‐related single nucleotide polymorphisms (SNPs) for pancreatic cancer (PC) risk remains elusive. We performed integrative bioinformatics analyses to select 31 SNPs located in miRNA‐target binding sites using the miRNASNP v2.0, a solid database providing miRNA‐related SNPs for genetic research, and investigated their associations with risk of PC in two large case‐control studies totally including 1847 cases and 5713 controls. We observed that the SNP rs3802266 is significantly associated with increased risk of PC (odds ratio (OR) = 1.21, 95% confidence intervals (CI) = 1.11‐1.31, P = 1.29E‐05). Following luciferase reporter gene assays show that rs3802266‐G creates a stronger binding site for miR‐181a‐2‐3p in 3′ untranslated region (3′UTR) of the gene ZHX2. Expression quantitative trait loci (eQTL) analysis suggests that ZHX2 expression is lower in individuals carrying rs3802266‐G with increased PC risk. In conclusion, our findings highlight the involvement of miRNA‐binding SNPs in PC susceptibility and provide new clues for PC carcinogenesis.     

Musashi2 promotes the progression of pancreatic cancer through a novel ISYNA1‐p21/ZEB‐1 pathway

Our previous studies found overexpression of Musashi2 (MSI2) conduced to the progression and chemoresistance of pancreatic cancer (PC) by negative regulation of Numb and wild type p53 (wtp53). Now, we further investigated the novel signalling involved with MSI2 in PC. We identified inositol‐3‐phosphate synthase 1 (ISYNA1) as a novel tumour suppressor regulated by MSI2. High MSI2 and low ISYNA1 expression were prevalently observed in 91 PC tissues. ISYNA1 expression was negatively correlated with MSI2 expression, T stage, vascular permeation and poor prognosis in PC patients. What's more, patients expressed high MSI2 and low ISYNA1 level had a significant worse prognosis. And in wtp53 Capan‐2 and SW1990 cells, ISYNA1 was downregulated by p53 silencing. ISYNA1 silencing promoted cell proliferation and cell cycle by inhibiting p21 and enhanced cell migration and invasion by upregulating ZEB‐1. However, MSI2 silencing upregulated ISYNA1 and p21 but downregulated ZEB‐1, which can be rescued by ISYNA1 silencing. Moreover, reduction of cell migration and invasion resulting from MSI2 silencing was significantly reversed by ISYNA1 silencing. In summary, MSI2 facilitates the development of PC through a novel ISYNA1‐p21/ZEB‐1 pathway, which provides new gene target therapy for PC.