Processing of syndecan-2 by matrix metalloproteinase-14 and effect of its cleavage on VEGF-induced tube formation of HUVECs

Lee, Young Hun,Park, Jun Hyoung,Cheon, Dong Huey,Kim, Taeyoung,Park, Yae Eun,Oh, Eok-Soo,Lee, Ji Eun,Lee, Seung-Taek Portland Press Ltd. 2017 Biochemical journal Vol. No.

<P>Syndecans (SDCs) are transmembrane proteoglycans that are involved in cell adhesion and cell communication. Specifically, SDC2 plays a key role in tumorigenesis, metastasis, and angiogenesis. Previously, we found that rat SDC2 is shed by matrix metalloproteinase-7 (MMP-7) in colon cancer cells. Here, we analyzed the susceptibility of rat SDC2 to various MMPs. We found that the rat SDC2 ectodomain (ECD) fused to the C-terminal Fc region, which was expressed in mammalian cells, was cleaved more efficiently by MMP-14 than MMP-7. Likewise, when anchored on the surface of HeLa cells, rat SDC2 was cleaved more efficiently by the treatment of MMP-14 than MMP-7 and was shed more readily by membrane-anchored MMP-14 than soluble MMP-14. Furthermore, MMP-14 cleaved recombinant SDC2-ECD expressed in <I>Escherichia coli</I> into multiple fragments. Using N-terminal amino acid sequencing and the top-down proteomics approach, we determined that the major cleavage sites were S<SUP>88</SUP>↓L<SUP>89</SUP>, T<SUP>98</SUP>↓M<SUP>99</SUP>, T<SUP>100</SUP>↓L<SUP>101</SUP>, D<SUP>132</SUP>↓P<SUP>133</SUP>, and N<SUP>148</SUP>↓L<SUP>149</SUP> for rat SDC2-ECD and S<SUP>55</SUP>↓G<SUP>56</SUP>, S<SUP>65</SUP>↓P<SUP>66</SUP>, P<SUP>75</SUP>↓K<SUP>76</SUP>, N<SUP>92</SUP>↓I<SUP>93</SUP> D<SUP>122</SUP>↓P<SUP>123</SUP>, and S<SUP>138</SUP>↓L<SUP>139</SUP> for human SDC2-ECD. Finally, the rat and human SDC2-ECD lost the ability to suppress vascular endothelial growth factor-induced formation of capillary-like tubes by human umbilical vein endothelial cells following cleavage by MMP-14, but its major cleavage-site mutant of rat SDC2-ECD did not. These results suggest that MMP-14 is a novel enzyme responsible for degrading SDC2 and impairing its physiological roles including angiogenesis.</P>

Human mesenchymal stem cells - current trends and future prospective

Ullah, Imran,Subbarao, Raghavendra ,Baregundi,Rho, Gyu ,Jin Portland Press Ltd. 2015 Bioscience reports Vol.35 No.2

<▼1><P>Stem cells are cells specialized cell, capable of renewing themselves through cell division and can differentiate into multi-lineage cells. These cells are categorized as embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and adult stem cells. Mesenchymal stem cells (MSCs) are adult stem cells which can be isolated from human and animal sources. Human MSCs (hMSCs) are the non-haematopoietic, multipotent stem cells with the capacity to differentiate into mesodermal lineage such as osteocytes, adipocytes and chondrocytes as well ectodermal (neurocytes) and endodermal lineages (hepatocytes). MSCs express cell surface markers like cluster of differentiation (CD)29, CD44, CD73, CD90, CD105 and lack the expression of CD14, CD34, CD45 and HLA (human leucocyte antigen)-DR. hMSCs for the first time were reported in the bone marrow and till now they have been isolated from various tissues, including adipose tissue, amniotic fluid, endometrium, dental tissues, umbilical cord and Wharton's jelly which harbours potential MSCs. hMSCs have been cultured long-term in specific media without any severe abnormalities. Furthermore, MSCs have immunomodulatory features, secrete cytokines and immune-receptors which regulate the microenvironment in the host tissue. Multilineage potential, immunomodulation and secretion of anti-inflammatory molecules makes MSCs an effective tool in the treatment of chronic diseases. In the present review, we have highlighted recent research findings in the area of hMSCs sources, expression of cell surface markers, long-term <I>in vitro</I> culturing, <I>in vitro</I> differentiation potential, immunomodulatory features, its homing capacity, banking and cryopreservation, its application in the treatment of chronic diseases and its use in clinical trials.</P></▼1><▼2><P>In this review, we highlighted recent research findings in the area of human mesenchymal stem cells, its application in the treatment of chronic diseases and its use in human clinical trials.</P></▼2>

Regulation of IGFBP-2 expression during fasting

Kang, Hye ,Suk,Kim, Mi-Young,Kim, Seung-Jae,Lee, Jae-Ho,Kim, Yong-Deuk,Seo, Young-Kyo,Bae, Jae-Hoon,Oh, Goo-Taeg,Song, Dae-Kyu,Ahn, Yong-Ho,Im, Seung-Soon Portland Press Ltd. 2015 Biochemical journal Vol.467 No.3

<▼1><P>Insulin-like growth factor (IGF)-binding protein-2 (IGFBP-2), one of the most abundant circulating IGFBPs, is known to attenuate the biological action of IGF-1. Although the effect of IGFBP-2 in preventing metabolic disorders is well known, its regulatory mechanism remains unclear. In the present study, we demonstrated the transcriptional regulation of the <I>Igfbp-2</I> gene by peroxisome-proliferator-activated receptor (PPAR) α in the liver. During fasting, both <I>Igfbp-2</I> and <I>PPARα</I> expression levels were increased. Wy14643, a selective PPARα agonist, significantly induced <I>Igfbp-2</I> gene expression in primary cultured hepatocytes. However, <I>Igfbp-2</I> gene expression in <I>Pparα</I> null mice was not affected by fasting or Wy14643. In addition, through transient transfection and chromatin immunoprecipitation assay in fasted livers, we determined that PPARα bound to the putative PPAR-responsive element between −511 bp and −499 bp on the <I>Igfbp-2</I> gene promoter, indicating that the <I>Igfbp-2</I> gene transcription is activated directly by PPARα. To explore the role of PPARα in IGF-1 signalling, we treated primary cultured hepatocytes with Wy14643 and observed a decrease in the number of IGF-1 receptors (IGF-1Rs) and in Akt phosphorylation. No inhibition was observed in the hepatocytes isolated from <I>Pparα</I> null mice. These results suggest that PPARα controls IGF-1 signalling through the up-regulation of hepatic <I>Igfbp-2</I> transcription during fasting and Wy14643 treatment.</P></▼1><▼2><P>Insulin-like growth factor (IGF)-binding protein-2 (IGFBP-2) is known to attenuate the biological action of IGF-1, but its regulatory mechanism remains unclear. We demonstrate the transcriptional regulation of the hepatic <I>Igfbp-2</I> gene by peroxisome-proliferator-activated receptor (PPAR) α during fasting. We also show how PPARα controls IGF-1 signalling through IGFBP-2.</P></▼2>

HBx induces the proliferation of hepatocellular carcinoma cells via AP1 over-expressed as a result of ER stress.

Cho, Hyun Kook,Kim, So Young,Kyaw, Yi Yi,Win, Aye Aye,Koo, Seung-Hoi,Kim, Hyeong-Hoe,Cheong, Jaehun Portland Press Ltd. 2015 Biochemical journal Vol.466 No.1

<P>Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and chronic hepatitis B virus (HBV) infection is the most common risk factor for HCC. The HBV proteins can induce oncogenic or synergy effects with a hyperproliferative response on transformation into HCC. CREBH (cAMP-responsive, element-binding protein H), activated by stress in the endoplasmic reticulum (ER), is an ER-resident transmembrane bZIP (basic leucine zipper) transcription factor that is specifically expressed in the liver. In the present study, we address the role played by CREBH activated by ER stress in HBV-induced hepatic cell proliferation. We confirmed CREBH activation by ER stress and showed that it occurred as a result of/via hepatitis B virus X (HBx)-induced ER stress. CREBH activated by HBx increased the expression of AP-1 target genes through c-Jun induction. Under pathological conditions such as liver damage or liver regeneration, activated CREBH may have an important role to play in hepatic inflammation and cell proliferation, as an insulin receptor with dual functions under these conditions. We showed that CREBH activated by HBx interacted with HBx protein, leading to a synergistic effect on the expression of AP-1 target genes and the proliferation of HCC cells and mouse primary hepatocytes. In conclusion, in HBV-infected hepatic cells or patients with chronic HBV, CREBH may induce proliferation of hepatic cells in co-operation with HBx, resulting in HCC.</P>

Arp2/3 complex regulates adipogenesis by controlling cortical actin remodelling.

Yang, Wulin,Thein, Shermaine,Lim, Chun-Yan,Ericksen, Russell E,Sugii, Shigeki,Xu, Feng,Robinson, Robert C,Kim, Jae Bum,Han, Weiping Portland Press Ltd. 2014 Biochemical journal Vol.464 No.2

<P>Extensive actin cytoskeleton remodelling occurs during adipocyte development. We have previously shown that disruption of stress fibres by the actin-severing protein cofilin is a requisite step in adipogenesis. However, it remains unclear whether actin nucleation and assembly into the cortical structure are essential for adipocyte development. In the present study we investigated the role of cortical actin assembly and of actin nucleation by the actin-related protein 2/3 (Arp2/3) complex in adipogenesis. Cortical actin structure formation started with accumulation of filamentous actin (F-actin) patches near the plasma membrane during adipogenesis. Depletion of Arp2/3 by knockdown of its subunits Arp3 or ARPC3 strongly impaired adipocyte differentiation, although adipogenesis-initiating factors were unaffected. Moreover, the assembly of F-actin-rich structures at the plasma membrane was suppressed and the cortical actin structure poorly developed after adipogenic induction in Arp2/3-deficient cells. Finally, we provide evidence that the cortical actin cytoskeleton is essential for efficient glucose transporter 4 (GLUT4) vesicle exocytosis and insulin signal transduction. These results show that the Arp2/3 complex is an essential regulator of adipocyte development through control of the formation of cortical actin structures, which may facilitate nutrient uptake and signalling events.</P>

The miR-19a/b family positively regulates cardiomyocyte hypertrophy by targeting atrogin-1 and MuRF-1.

Song, Dong Woo,Ryu, Jae Yong,Kim, Jin Ock,Kwon, Eun Jeong,Kim, Do Han Portland Press Ltd. 2014 Biochemical journal Vol.457 No.1

<P>Progressive cardiac hypertrophy owing to pathological stimuli, such as pressure overload, is frequently associated with the development of heart failure, a major cause of morbidity and mortality worldwide. Growing evidence has shown that miRNAs are extensively involved in the pathogenesis of cardiac hypertrophy. In the present study, we examined the hypothesis that the miR-19a/b family acts as a key regulator of cardiac hypertrophy and apoptosis. Forced overexpression of miR-19a/b was sufficient to induce hypertrophy in rat neonatal cardiomyocytes. Luciferase assays revealed that miR-19a/b directly target the anti-hypertrophic genes atrogin-1 and MuRF-1 (muscle RING-finger protein-1). The endogenous expressions of the target genes were down-regulated by miR-19a/b. Pro-hypertrophic calcineurin/NFAT (nuclear factor of activated T-cells) signalling was elevated markedly in the presence of miR-19b, and the calcineurin inhibitor CsA (cyclosporin A) and the PKC (protein kinase C) inhibitor GF10923X significantly attenuated the miR-19b-mediated increase in cell size and expression of hypertrophic markers. Furthermore, miR-19b led to increased cell survival through up-regulation of the NFAT target gene encoding α-crystallin-B and repression of the pro-apoptotic gene Bim (Bcl-2-interacting mediator of cell death) under ER (endoplasmic reticulum) stress conditions. Taken together, the results of the present study demonstrate that the miR-19a/b family regulates phenotypes of cardiomyocytes via suppression of multiple direct target genes.</P>

Crystal structure of xenotropic murine leukaemia virus-related virus (XMRV) ribonuclease H

Kim, Ju ,Hee,Kang, Sunghyun,Jung, Suk-Kyeong,Yu, Keum ,Ran,Chung, Sang ,J.,Chung, Bong ,Hyun,Erikson, Raymond ,L.,Kim, Bo ,Yeon,Kim, Seung ,Jun Portland Press Ltd. 2012 Bioscience reports Vol.32 No.5

<P>RNase H (retroviral ribonuclease H) cleaves the phosphate backbone of the RNA template within an RNA/DNA hybrid to complete the synthesis of double-stranded viral DNA. In the present study we have determined the complete structure of the RNase H domain from XMRV (xenotropic murine leukaemia virus-related virus) RT (reverse transcriptase). The basic protrusion motif of the XMRV RNase H domain is folded as a short helix and an adjacent highly bent loop. Structural superposition and subsequent mutagenesis experiments suggest that the basic protrusion motif plays a role in direct binding to the major groove in RNA/DNA hybrid, as well as in establishing the co-ordination among modules in RT necessary for proper function.</P>

Effect of the guide strand 3'-end structure on the gene-silencing potency of asymmetric siRNA

Hong, S.W.,Park, J.H.,Yun, S.,Lee, C.H.,Shin, C.,Lee, D.-k. Portland Press Ltd. 2014 Biochemical journal Vol.461 No.3

Chromatin looping and eRNA transcription precede the transcriptional activation of gene in the β-globin locus

Kim, Yea ,Woon,Lee, Sungkung,Yun, Jangmi,Kim, AeRi Portland Press Ltd. 2015 Bioscience reports Vol.35 No.2

<▼1><P>Enhancers are closely positioned with actively transcribed target genes by chromatin looping. Non-coding RNAs are often transcribed on active enhancers, referred to as eRNAs (enhancer RNAs). To explore the kinetics of enhancer–promoter looping and eRNA transcription during transcriptional activation, we induced the β-globin locus by chemical treatment and analysed cross-linking frequency between the β-globin gene and locus control region (LCR) and the amount of eRNAs transcribed on the LCR in a time course manner. The cross-linking frequency was increased after chemical induction but before the transcriptional activation of gene in the β-globin locus. Transcription of eRNAs was increased in concomitant with the increase in cross-linking frequency. These results show that chromatin looping and eRNA transcription precedes the transcriptional activation of gene. Concomitant occurrence of the two events suggests functional relationship between them.</P></▼1><▼2><P>Chromatin looping between enhancer and promoter was generated after chemical induction but before the transcriptional activation of gene in the β-globin locus. Transcription of enhancer RNAs was increased in concomitant with the increase of chromatin looping in this locus.</P></▼2>

Cell imaging and DNA delivery in fibroblastic cells by conjugated polyelectrolytes

Shin, Y. C.,Lee, J. H.,Jeong, J. E.,Kim, B.,Lee, E. J.,Jin, O. S.,Jung, T. G.,Lee, J. J.,Woo, H. Y.,Han, D. W. PORTLAND PRESS LTD 2013 Biotechnology and applied biochemistry Vol.60 No.6