Downregulation of Wnt-Mediated ROS generation is causally implicated in leprechaunism

Although mutations in the insulin receptor have been causally implicated with leprechaunsim, the full pathophysiology of the syndrome cannot be accounted for by malfunction of this gene alone. We sought to characterize a connection between Wnt-mediated cell signaling and the production of reactive oxygen species (ROS) which revealed a novel mechanistic basis for understanding the pathogenesis of leprechaunism. To identify candidate genes involved in this process, a PCR-based subtractive hybridization was performed. Candidate genes were examined for interaction with the Wnt signaling pathway and ROS generation. We found that Dickkopf 1 (Dkk1), a Wnt inhibitor, is overexpressed in skin fibroblast cells derived from three leprechaunism patients and that the cells showed an impaired response to Wnt2 in terms of β-catenin-Tcf activation. Knockdown of Dkk1 in the patient cell lines rescued Wnt2-mediated Tcf activation. Concerted action of Wnt2 and knockdown of Dkk1 resulted in enhanced Nox4 expression and PDGF-induced ROS generation compared to parental patient cells. Furthermore, we found that NFATc2 was activated in response to Wnt2 stimulation and directly activates Nox4 expression. These data show a crosstalk between Wnt and ROS pathways which in turn provides new mechanistic insights at the molecular level into the pathogenesis of leprechaunism.     

The differential affinity of the usher for chaperone–subunit complexes is required for assembly of complete pili

Attachment to host cells via adhesive surface structures is a prerequisite for the pathogenesis of many bacteria. Uropathogenic Escherichia coli assemble P and type 1 pili for attachment to the host urothelium. Assembly of these pili requires the conserved chaperone/usher pathway, in which a periplasmic chaperone controls the folding of pilus subunits and an outer membrane usher provides a platform for pilus assembly and secretion. The usher has differential affinity for pilus subunits, with highest affinity for the tip‐localized adhesin. Here, we identify residues F21 and R652 of the P pilus usher PapC as functioning in the differential affinity of the usher. R652 is important for high‐affinity binding to the adhesin whereas F21 is important for limiting affinity for the PapA major rod subunit. PapC mutants in these residues are specifically defective for pilus assembly in the presence of PapA, demonstrating that differential affinity of the usher is required for assembly of complete pili. Analysis of PapG deletion mutants demonstrated that the adhesin is not required to initiate P pilus biogenesis. Thus, the differential affinity of the usher may be critical to ensure assembly of functional pilus fibres.     

Slc25a17 acts as a peroxisomal coenzyme A transporter and regulates multiorgan development in zebrafish

Slc25a17 is known as a peroxisomal solute carrier, but the in vivo role of the protein has not been demonstrated. We found that the zebrafish genome contains two slc25a17 genes that function redundantly, but additively. Notably, peroxisome function in slc25a17 knockdown embryos is severely compromised, resulting in an altered lipid composition. Along the defects found in peroxisome-associated phenotypic presentations, we highlighted that development of the swim bladder is also highly dependent on Slc25a17 function. As Slc25a17 showed substrate specificity towards coenzyme A (CoA), injecting CoA, but not NAD⁺, rescued the defective swim bladder induced by slc25a17 knockdown. These results indicated that Slc25a17 acts as a CoA transporter, involved in the maintenance of functional peroxisomes that are essential for the development of multiple organs during zebrafish embryogenesis. Given high homology in protein sequences, the role of zebrafish Slc25a17 may also be applicable to the mammalian system.     

Lipid phosphatase SHIP-1 regulates chondrocyte hypertrophy and skeletal development

SH2-containing inositol-5′-phosphatase-1 (SHIP-1) controls the phosphatidylinositol-3′-kinase (PI3K) initiated signaling pathway by limiting cell membrane recruitment and activation of Akt. Despite the fact that many of the growth factors important to cartilage development and functions are able to activate the PI3K signal transduction pathway, little is known about the role of PI3K signaling in chondrocyte biology and its contribution to mammalian skeletogenesis. Here, we report that the lipid phosphatase SHIP-1 regulates chondrocyte hypertrophy and skeletal development through its expression in osteochondroprogenitor cells. Global SHIP-1 knockout led to accelerated chondrocyte hypertrophy and premature formation of the secondary ossification center in the bones of postnatal mice. Drastically higher vascularization and greater number of c-kit + progenitors associated with sinusoids in the bone marrow also indicated more advanced chondrocyte hypertrophic differentiation in SHIP-1 knockout mice than in wild-type mice. In corroboration with the in vivo phenotype, SHIP-1 deficient PDGFRα + Sca-1 + osteochondroprogenitor cells exhibited rapid differentiation into hypertrophic chondrocytes under chondrogenic culture conditions in vitro. Furthermore, SHIP-1 deficiency inhibited hypoxia-induced cellular activation of Akt and extracellular-signal-regulated kinase (Erk) and suppressed hypoxia-induced cell proliferation. These results suggest that SHIP-1 is required for hypoxia-induced growth signaling under physiological hypoxia in the bone marrow. In conclusion, the lipid phosphatase SHIP-1 regulates skeletal development by modulating chondrogenesis and the hypoxia response of the osteochondroprogenitors during endochondral bone formation.     

High‐Performance Tandem Organic Solar Cells Using HSolar as the Interconnecting Layer

Tandem structure provides a practical way to realize high efficiency organic photovoltaic cells, it can be used to extend the wavelength coverage for light harvesting. The interconnecting layer (ICL) between subcells plays a critical role in the reproducibility and performance of tandem solar cells, yet the processability of the ICL has been a challenge. In this work the fabrication of highly reproducible and efficient tandem solar cells by employing a commercially available material, PEDOT:PSS HTL Solar (HSolar), as the hole transporting material used for the ICL is reported. Comparing with the conventional PEDOT:PSS Al 4083 (c‐PEDOT), HSolar offers a better wettability on the underlying nonfullerene photoactive layers, resulting in better charge extraction properties of the ICL. When FTAZ:IT‐M and PTB7‐Th:IEICO‐4F are used as the subcells, a power conversion efficiency (PCE) of 14.7% is achieved in the tandem solar cell. To validate the processability of these tandem solar cells, three other research groups have successfully fabricated tandem devices using the same recipe and the highest PCE obtained is 16.1%. With further development of donor polymers and device optimization, the device simulation results show that a PCE > 22% can be realized in tandem cells in the near future.     

In vitro wound healing: Inhibition activity of insect‐derived mAb CO17‐1A in human colorectal cancer cell migration

The monoclonal antibody (mAb) CO17‐1A specifically binds to the tumor‐associated cell surface glycoprotein GA733 in colorectal cancer cells. Thus, mAb CO17‐1A has the potential to act as an immune therapeutic protein against colorectal cancer. Recently, it was shown that the baculovirus insect cell expression system produces anti‐colorectal cancer mAb CO17‐1A. In this study, the colorectal cancer antibody mAb CO17‐1A fused to the endoplasmic reticulum (ER) retention signal sequence (KDEL), and the (mAb CO17‐1AK) was expressed in Spodoptera frugiperda Sf9 insect cells. The yield, cell cytotoxicity, and in vitro anti‐tumor activity of mAb CO17‐1AK were verified. Western blotting was performed to confirm that both heavy and light chains of mAb CO17‐1A were expressed in Sf9 insect cells. The insect‐derived mAb (mAb^I) CO17‐1A was purified using a protein G affinity column. An in vitro wound healing assay was conducted to determine the inhibition activity of mAb CO17‐1A during tumor cell migration, showing that mAb^I CO17‐1AK was effective as mammalian‐derived mAb CO17‐1A (mAb^M CO17‐1A). These results suggest that the insect cell expression system can produce and properly assemble mAbs that inhibit tumor cell migration.     

Fuscibacter oryzae gen. nov., sp. nov., a phosphate-solubilizing bacterium isolated from the rhizosphere of rice plant

An ovoid to rod shaped, white to brown pigmented, facultative anaerobic, mesophilic, non-phototrophic, Gram-staining-negative, non-motile, multiply by binary fission designated strain KVB23^T, which was isolated from root of rice plant, near Ilsan, South Korea, was investigated for its taxonomic position by polyphasic approach. Optimal growth was found to occur at 30?C, at pH 6.5 and in the absence of NaCl on R2A. Phylogenetic analysis based on the 16S rRNA gene sequence of strain KVB23^T revealed that it formed a distinct lineage, as a separate deep branch within the family Rhodobacteriaceae, with?<?96.5% sequence similarity to representatives of the genera Rhodobacter, Xinfangfangia, Tabrizicola, Falsirhodobacter, Haematobacter, Paenirhodobacter, Pseudorhodobacter and Pararhodobacter. Based in 16S rRNA sequences strain KVB23^T was most closely related to Tabrizicola fusiformis KCTC 62105 ^T (96.5%) and Rhodobacter thermarum KCTC 52712 ^T (96.2%). The draft genome of strain KVB23^T was 3.80 bp long with a DNA G?+?C content of 63.1%. Genome of strain KVB23^T harboured gene clusters for tryptophan and cobalamin biosynthesis. The strain contained Q-10 as the sole respiratory quinone. The predominant fatty acids were found to consist of C_16:0, C_18:0 and summed feature 8 (comprising C_18:1 ω7c and / or C_18:1 ω6). The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, seven unidentified phosphoglycolipids, two unidentified aminophosphoglycolipid, one unidentified glycolipid and four unidentified lipids. Phosphate-solubilizing bacteria have the ability to dissolve insoluble phosphates and enhance the soil fertility. Strain KVB23^T can solubilize calcium phosphate tribasic. Phosphate solubilizing and tryptophan biosynthesis property of strain KVB23^T could be a possible factor for the increase in growth of rice plant. Differential phenotypic, chemotaxonomic and genotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain KVB23^T was found to represent a novel genus in the Rhodobacteriaceae family, for which the name Fuscibacter oryzae gen. nov., sp. nov. is proposed, with the type strain KVB23^T(=?KACC 21711 ^T?=?NBRC 114716 ^T).