Oncogene-dependent addiction to carbohydrate-responsive element binding protein in hepatocellular carcinoma

Metabolic reprogramming is a hallmark of many cancer types, including hepatocellular carcinoma (HCC). Identifying the critical players in this process might be crucial for the generation of novel and effective anti-neoplastic therapies. In the present investigation, we determined the importance of carbohydrate responsive element binding protein (ChREBP), a central player in the regulation of lipid and glucose metabolism in the liver, on the development of HCC in in vitro and in vivo models. We found that genetic deletion of ChREBP (that will be referred to as ChREBPKO mice) strongly delays or impairs hepatocarcinogenesis driven by AKT or AKT/c-Met overexpression in mice, respectively. In contrast, HCC development was found to be completely unaffected by ChREBP depletion in mice co-expressing AKT and N-Ras protooncogenes. In mouse and human HCC cell lines, suppression of ChREBP via specific small interfering RNAs (siRNAs) resulted in decreased proliferation and induction of apoptosis. Of note, these cellular events were strongly augmented by concomitant inhibition of the mitogen-activated protein kinase (MAPK) pathway. The present data indicate that ChREBP activity might be required or dispensable for HCC growth, depending on the oncogenes involved. In particular, the activation of Ras/MAPK signaling might represent a possible mechanism of resistance to ChREBP depletion in this tumor type. Additional studies are needed to unravel the molecular mechanisms rendering HCC cells insensitive to ChREBP suppression.     

<Emphasis Type="Italic">Roseomonas aeriglobus</Emphasis> sp. nov., isolated from an air-conditioning system

A novel pale pink-coloured, strictly aerobic, Gram-stain negative bacterial strain, designated strain KER25-12^T, was isolated from a laboratory air-conditioning system in South Korea. Cells were observed to be non-motile cocci showing positive catalase and oxidase reactions. Strain KER25-12^T was found to grow at 10–30 °C (optimum, 25–30 °C), at pH 4.0–9.0 (optimum, pH 6.0–7.0) and in the presence of 0–2% (w/v) NaCl (optimum, 0%). Ubiquinone-10 and spermidine were detected as the sole respiratory quinone and the predominant polyamine, respectively. The major fatty acids were identified as summed feature 8 (comprising C_18:1 ω7c and/or C_18:1 ω6c), summed feature 3 (comprising C_16:1 ω7c and/or C_16:1 ω6c), C_16:0 and C_18:0. The genomic DNA G+C content of strain KER25-12^T was determined to be 70.0 mol%. The major polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified aminolipid. Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain KER25-12^T belongs to the genus Roseomonas and shows high sequence similarity to Roseomonas aerilata 5420S-30^T (98.57%), Roseomonas pecuniae N75^T (97.44%) and Roseomonas vinacea CPCC 100056^T (97.40%). Based on the morphological, physiological, chemotaxonomic and phylogenetic features, strain KER25-12^T is concluded to represent a novel species of the genus Roseomonas, for which the name Roseomonas aeriglobus sp. nov. is proposed. The type strain is KER25-12^T (= KACC 19282^T = JCM 32049^T).     

Circ-8073 regulates CEP55 by sponging miR-449a to promote caprine endometrial epithelial cells proliferation via the PI3K/AKT/mTOR pathway

Circular RNAs (circRNAs) are a large class of endogenous non-coding RNAs that function as regulators in various cells and tissues. Here, the function and mechanism of circRNA8073 (Circ-8073) on endometrial epithelial cells (EECs) and the development of endometrial receptivity were investigated in dairy goats. Circ-8073 could bind to and inhibit miR-449a activity. Circ-8073 binding to the target site of miR-449a had a negative feedback relationship. Centrosomal protein55 (CEP55) was a direct target gene of miR-449a, and Circ-8073 could increase the expression levels of CEP55 by sponging miR-449a in EECs in vitro. Circ-8073/miR-449a/CEP55 could promote EECs proliferation via the PI3K/AKT/mTOR pathway. In addition, CEP55 could regulate the expression levels of vascular endothelial growth factor (VEGF) and forkhead box M1 (FOXM1) in EECs, which contributed to the development of endometrial receptivity. These findings showed that Circ-8073 regulated CEP55 by sponging miR-449a to promote EEC proliferation via the PI3K/AKT/mTOR pathway, suggesting that it could function as a regulator in the development of endometrial receptivity in dairy goats.     

A new genus and three new species of miniaturized microhylid frogs from Indochina(Amphibia: Anura:Microhylidae: Asterophryinae)

We report on the discovery of a new genus of microhylid subfamily Asterophryinae from northern and eastern Indochina, containing three new species.Vietnamophryne Gen. nov. are secretive miniaturized frogs(SVL21 mm) with a mostly semi-fossorial lifestyle. To assess phylogenetic relationships, we studied 12 S rRNA – 16 S rRNA mt DNA fragments with a final alignment of 2 591 bp for 53 microhylid species. Morphological and osteological characters were analyzed using micro-CT scanning and used to describe the new genus. Results of phylogenetic analyses assigned the new genus into the mainly Australasian subfamily Asterophryinae as a sister taxon to the genus Siamophryne from southern Indochina. The three specimens collected from Gia Lai Province in central Vietnam, Cao Bang Province in northern Vietnam, and Chiang Rai Province in northern Thailand proved to be separate species, different both in morphology and genetics(genetic divergence 3.1%≤P≤5.1%). Our work provides further evidence for the "out of Indo-Eurasia"scenario for Asterophryinae, indicating that the initial cladogenesis and differentiation of this group of frogs occurred in the Indochina Peninsula. To date, each of the three new species of Vietnamophryne Gen. nov. is known only from a single specimen; thus,their distribution, life history, and conservation status require further study.     

Neuroprotective Effects of n-3 Polyunsaturated Fatty Acid-Enriched Phosphatidylserine Against Oxidative Damage in PC12 Cells

Neurodegenerative diseases are defined by progressive loss of specific neuronal cell populations and are associated with protein aggregates. Oxidative stress has been implicated in their pathological processes. Previous studies revealed that docosahexaenoic acid (DHA) is beneficial in neurodegenerative diseases. Phospholipids (PLs) derived from marine products are rich in DHA and eicosapentaenoic acid (EPA). In the present study, we investigated the neuroprotective effects of DHA-enriched and unenriched phosphatidylcholine (PC) and phosphatidylserine (PS) on oxidative stress induced by hydrogen peroxide (H₂O₂) and tert-butylhydroperoxide in PC12 cells. Cell viability and leakage of lactate dehydrogenase results showed that the neuroprotective effect of PS was superior to that of PC. DHA- and EPA-enriched PC and PS were superior to that without DHA or EPA; in addition, the improvement with n-3 polyunsaturated fatty acid-enriched PS (n-3 PS) was dose dependent. Acridine orange/ethidium bromide staining showed that DHA- and EPA-enriched PS (DHA/EPA-PS) could significantly inhibit apoptosis. Mechanistic studies revealed that EPA-PS and DHA-PS were effective to increase superoxide dismutase (SOD) levels by 48.4 and 58.2 % and total antioxidant capacity (T-AOC) level by 51 and 94 %, respectively, in the H₂O₂ model. Similar results for SOD and T-AOC levels were shown in the t-BHP model. EPA/DHA-PS could downregulate the messenger RNA level of Caspase-3, Caspase-9, and Bax, upregulate Bcl-2, inhibit Bax, and increase Bcl-2 at protein level. In conclusion, EPA/DHA-PS could protect PC12 cells from oxidative stress and prevent mitochondrial-mediated apoptosis. Our findings indicate that the neuroprotective effects of DHA/EPA-PLs depend on the molecular form. Further studies are necessary to reveal detailed mechanisms and structure–effect relationships.     

Formation of Avenacein Y by<Emphasis Type="Italic">Fusarium avenaceum</Emphasis> Fries Sacc. isolates from poland and biological properties of the compound

Eighteen isolates ofFusarium avenaceum Fries Sacc. originating from cereals, potato and carrot from Poland synthesized Avenacein Y in amounts ranging from 0.01 to 2.0 g/kg of wheat grain. The compound was produced in 1 kg of corn kernels by isolate KF-58, isolated, identified and used to test for antibiotic activity against plant pathogenic fungi of 11 genera. Application of Avenacein Y caused slight decrease of mycelium growth in four species only.     

Free proline contents in two different groups of rice mutants resistant to hydroxy-L-proline

Summary In four rice (Oryza sativa L.) mutants resistant to hydroxy-L-proline (Hyp), HYP101, HYP203, HYP205 and HYP210, and in their original variety, Nipponbare, free proline and Hyp contents in the seeds and in the 14-day-old seedlings have been determined. The four mutants can be divided into two groups: HYP101 and HYP203 are classified as to recessive gene and the levels of free proline are similar to that of the original variety; the second group includes mutants HYP205 and HYP210 where the Hyp resistance is transmitted heterozygously and, both in the seeds and in the seedlings, a remarkable increase in free proline content is observed. In particular, free proline contents in the seeds of HYP205 and HYP210 are, respectively, 24 and 12 times that of the original variety. Hyp is detected only in the seedlings cultured with Hyp solution. In the Hyp resistant seedlings of HYP205 and HYP210, Hyp contents are twice that of the original variety and less than half in the seedlings of HYP101 and HYP203. Hyp resistance and differential proline levels are also evident in the callus initiated from the mutants. This suggests that the Hyp resistant mutants are good genetic markers both in planta and in vitro. The Hyp mutants are also discussed with regard to stress resistance.     

Sinensetin ameliorates high glucose-induced diabetic nephropathy via enhancing autophagy in vitro and in vivo

Diabetic nephropathy (DN) affects around 40% of people with diabetes, the final outcome of which is end-stage renal disease. The deficiency of autophagy and excessive oxidative stress have been found to participate in the pathogenesis of DN. Sinensetin (SIN) has been proven to have strong antioxidant capability. However, the effect of SIN on DN has not been studied. We examined the effect of SIN on cell viability and autophagy in the podocyte cell line, MPC5 cells, treated with high glucose (HG). For in vivo studies, DN mice models were established by intraperitoneal injected with streptozotocin (40 mg/kg) for 5 consecutive days and fed with a 60% high-fat diet, and SIN was given (10, 20, and 40 mg/kg) for 8 weeks via intraperitoneal injection. The results showed that SIN could protect MPC5 cells against HG-induced damage and significantly improve the renal function of DN mice. Moreover, SIN remarkably restored the autophagy activity of MPC5 cells which was inhibited under HG conditions. Consistent with this, SIN efficiently improved autophagy in the kidney tissue of DN mice. In brief, our findings demonstrated the protective effect of SIN on DN via restoring the autophagic function, which might provide a basis for drug development.     

Concanavalin A distorts the beta-GlcNAc-(1-->2)-Man linkage of beta- GlcNAc-(1-->2)-alpha-Man-(1-->3)-[beta-GlcNAc-(1-->2)-alpha-Man- (1-- >6)]-Man upon binding

Carbohydrate recognition by proteins is a key event in many biological processes. Concanavalin A is known to specifically recognize the pentasaccharide core (beta-GlcNAc-(1-->2)-alpha- Man-(1-->3)-[beta- GlcNAc-(1-->2)-alpha-Man-(1-->6)]-Man) of N-linked oligosaccharides with a Ka of 1.41 x 10(6 )M-1. We have determined the structure of concanavalin A bound to beta-GlcNAc-(1-->2)-alpha-Man-(1-->3)-[beta- GlcNAc-(1-->2)-alpha-Man- (1-->6)]-Man to 2.7A. In six of eight subunits there is clear density for all five sugar residues and a well ordered binding site. The pentasaccharide adopts the same conformation in all eight subunits. The binding site is a continuous extended cleft on the surface of the protein. Van der Waals interactions and hydrogen bonds anchor the carbohydrate to the protein. Both GlcNAc residues contact the protein. The GlcNAc on the 1-->6 arm of the pentasaccharide makes particularly extensive contacts and including two hydrogen bonds. The binding site of the 1-->3 arm GlcNAc is much less extensive. Oligosaccharide recognition by Con A occurs through specific protein carbohydrate interactions and does not require recruitment of adventitious water molecules. The beta-GlcNAc-(1-->2)-Man glycosidic linkage PSI torsion angle on the 1-->6 arm is rotated by over 50 degrees from that observed in solution. This rotation is coupled to disruption of interactions at the monosaccharide site. We suggest destabilization of the monosaccharide site and the conformational strain reduces the free energy liberated by additional interactions at the 1-->6 arm GlcNAc site.