Phenyl 2‐pyridyl ketoxime induces cellular senescence‐like alterations via nitric oxide production in human diploid fibroblasts

Yang, Kyeong Eun,Jang, Hyun&#x2010,Jin,Hwang, In&#x2010,Hu,Chung, Young&#x2010,Ho,Choi, Jong&#x2010,Soon,Lee, Tae&#x2010,Hoon,Chung, Yun&#x2010,Jo,Lee, Min&#x2010,Seung,Lee, Mi Young,Yeo, Eui&#x2010,J BLACKWELL PUBLISHING 2016 AGING CELL Vol.15 No.2

<P><B>Summary</B></P><P>Phenyl‐2‐pyridyl ketoxime (PPKO) was found to be one of the small molecules enriched in the extracellular matrix of near‐senescent human diploid fibroblasts (HDFs). Treatment of young HDFs with PPKO reduced the viability of young HDFs in a dose‐ and time‐dependent manner and resulted in senescence‐associated β‐galactosidase (SA‐β‐gal) staining and G2/M cell cycle arrest. In addition, the levels of some senescence‐associated proteins, such as phosphorylated ERK1/2, caveolin‐1, p53, p16<SUP>ink4a</SUP>, and p21<SUP>waf1</SUP>, were elevated in PPKO‐treated cells. To monitor the effect of PPKO on cell stress responses, reactive oxygen species (ROS) production was examined by flow cytometry. After PPKO treatment, ROS levels transiently increased at 30 min but then returned to baseline at 60 min. The levels of some antioxidant enzymes, such as catalase, peroxiredoxin II and glutathione peroxidase I, were transiently induced by PPKO treatment. SOD II levels increased gradually, whereas the SOD I and III levels were biphasic during the experimental periods after PPKO treatment. Cellular senescence induced by PPKO was suppressed by chemical antioxidants, such as N‐acetylcysteine, 2,2,6,6‐tetramethylpiperidinyloxy, and L‐buthionine‐(<I>S</I>,<I>R</I>)‐sulfoximine. Furthermore, PPKO increased nitric oxide (NO) production via inducible NO synthase (iNOS) in HDFs. In the presence of NOS inhibitors, such as L‐NG‐nitroarginine methyl ester and L‐NG‐monomethylarginine, PPKO‐induced transient NO production and SA‐β‐gal staining were abrogated. Taken together, these results suggest that PPKO induces cellular senescence in association with transient ROS and NO production and the subsequent induction of senescence‐associated proteins<B>.</B></P>

Areca nut exposure increases secretion of tumor‐promoting cytokines in gingival fibroblasts that trigger DNA damage in oral keratinocytes

Illeperuma, Rasika P.,Kim, Do Kyeong,Park, Young Jin,Son, Hwa Kyung,Kim, Jue Young,Kim, Jinmi,Lee, Doo Young,Kim, Ki&#x2010,Yeol,Jung, Da&#x2010,Woon,Tilakaratne, Wanninayake M.,Kim, Jin Alan R. Liss, Inc 2015 International journal of cancer Vol.137 No.11

<▼1><P>Molecular crosstalk between cancer cells and fibroblasts has been an emerging hot issue in understanding carcinogenesis. As oral submucous fibrosis (OSF) is an inflammatory fibrotic disease that can potentially transform into squamous cell carcinoma, OSF has been considered to be an appropriate model for studying the role of fibroblasts during early stage carcinogenesis. In this sense, this study aims at investigating whether areca nut (AN)‐exposed fibroblasts cause DNA damage of epithelial cells. For this study, immortalized hNOF (hTERT‐hNOF) was used. We found that the levels of GRO‐α, IL‐6 and IL‐8 increased in AN‐exposed fibroblasts. Cytokine secretion was reduced by antioxidants in AN‐exposed fibroblasts. Increase in DNA double strand breaks (DSB) and 8‐oxoG FITC‐conjugate was observed in immortalized human oral keratinocytes (IHOK) after the treatment of cytokines or a conditioned medium derived from AN‐exposed fibroblasts. Cytokine expression and DNA damage were also detected in OSF tissues. The DNA damage was reduced by neutralizing cytokines or antioxidant treatment. Generation of reactive oxygen species (ROS) and DNA damage response, triggered by cytokines, were abolished when NADPH oxidase (NOX) 1 and 4 were silenced in IHOK, indicating that cytokine‐triggered DNA damage was caused by ROS generation through NOX1 and NOX4. Taken together, this study provided strong evidence that blocking ROS generation might be a rewarding approach for cancer prevention and intervention in OSF.</P></▼1><▼2><P><B>What's new?</B></P><P>Fibroblasts in the tumor microenvironment influence tumor initiation and growth and are of particular interest in oral submucous fibrosis (OSF), a progressive fibrotic disease of malignant potential. This study shows that the release of tumor‐promoting cytokines by fibroblasts exposed to areca nut, the primary cause of OSF, induce DNA damage in oral keratinocytes. The findings suggest that fibroblasts indirectly promote epithelial transformation in OSF by secreting cytokines, whereby DNA damage of epithelial cells is inflicted by reactive oxygen species generated <I>via</I> NADPH oxidases. These insights could inform the development of new therapeutic approaches for OSF.</P></▼2>

IKK‐β‐mediated myeloid cell activation exacerbates inflammation and inhibits recovery after spinal cord injury

Kang, Junghee,Jiang, Mei Hua,Min, Hyun Jung,Jo, Eun&#x2010,Kyeong,Lee, Soojin,Karin, Michael,Yune, Tae Young,Lee, Sung Joong WILEY‐VCH Verlag 2011 European journal of immunology Vol.41 No.5

<P><B>Abstract</B></P><P>Traumatic spinal cord injury (SCI) is followed by massive infiltration and activation of myeloid cells such as neutrophils and macrophages, but the functions of these cells are controversial. In this study, our objective was to elucidate the in vivo role of a signaling pathway involved in activation of these innate immune cells in SCI using myeloid cell‐specific IκB kinase (IKK)‐β conditional knockout (<TEX>${\rm {ikk}}{\rm {\beta}}^{\Delta mye}$</TEX><IMG src='/wiley-blackwell_img/equation/tex2gif-ueqn-1.gif' alt ='equation image'/> ) mice. In these mice, the <I>ikk</I>β gene has been specifically deleted from myeloid cells, compromising their in vivo IKK/NF‐κB‐dependent activation. We found that <TEX>${\rm {ikk}}{\rm {\beta}}^{\Delta mye}$</TEX><IMG src='/wiley-blackwell_img/equation/tex2gif-ueqn-2.gif' alt ='equation image'/> mice had significantly reduced neutrophil and macrophage infiltrations after SCI compared to <I>ikk</I>β<SUP>+/+</SUP> controls. SCI‐induced proinflammatory gene expression was also reduced in <TEX>${\rm {ikk}}{\rm {\beta}}^{\Delta mye}$</TEX><IMG src='/wiley-blackwell_img/equation/tex2gif-ueqn-3.gif' alt ='equation image'/> mice. Reduced neuroinflammation in <TEX>${\rm {ikk}}{\rm {\beta}}^{\Delta mye}$</TEX><IMG src='/wiley-blackwell_img/equation/tex2gif-ueqn-4.gif' alt ='equation image'/> mice was accompanied by attenuated neuronal loss and behavioral deficits in motor activity. In addition, the SCI‐induced expression of CXC ligand 1 was reduced in <TEX>${\rm {ikk}}{\rm {\beta}}^{\Delta mye}$</TEX><IMG src='/wiley-blackwell_img/equation/tex2gif-ueqn-5.gif' alt ='equation image'/> mice, which may be responsible for the reduced neutrophil infiltration in these mice. Our data demonstrate that IKK‐β‐dependent myeloid cell activation potentiates neuroinflammation and neuronal damage after SCI.</P>

Peroxiredoxin‐1, a possible target in modulating inflammatory cytokine production in macrophage like cell line RAW264.7

Tae Lim, Young,Sup Song, Dong,Joon Won, Tae,Lee, Yun&#x2010,Jung,Yoo, Jong&#x2010,Sun,Eun Hyung, Kyeong,Won Yoon, Joo,Park, So&#x2010,Young,Woo Hwang, Kwang Blackwell Publishing Asia 2012 Microbiology and immunology Vol.56 No.6

<P><B>ABSTRACT</B></P><P>Peroxiredoxin (PRX), a scavenger of H<SUB>2</SUB>O<SUB>2</SUB> and alkyl hydroperoxides in living organisms, protects cells from oxidative stress. Contrary to its known anti‐oxidant roles, the involvement of PRX‐1 in the regulation of lipopolysaccharide (LPS) signaling is poorly understood, possible immunological functions of PRX‐1 having been uncovered only recently. In the present study, it was discovered that the PRX‐1 deficient macrophage like cell line (RAW264.7) has anti‐inflammatory activity when stimulated by LPS. Treatment with LPS for 3 hrs resulted in increased gene expression of an anti‐inflammatory cytokine, interleukin‐10 (IL‐10), in PRX‐1 knock down RAW264.7 cells. Gene expression of pro‐inflammatory cytokines IL‐1β and tumor necrosis factor‐ α (TNF‐α) did not show notable changes under the same conditions. However, production of these cytokines significantly decreased in PRX‐1 knock down RAW264.7 cells with 12 hrs of stimulation. Production of IL‐10 was also increased in PRX‐1 knock down RAW264.7 cells with 12 hrs of stimulation. We predicted that higher concentrations of IL‐10 would result in decreased expression of IL‐1β and TNF‐α in PRX‐1 knock‐down cells. This was confirmed by blocking IL‐10, which reestablished IL‐1β and TNF‐α secretion. We also observed that increased concentrations of IL‐10 do not affect the NF‐κB pathway. Interestingly, STAT3 phosphorylation by LPS stimulation was significantly increased in PRX‐1 knockdown RAW264.7 cells. Up‐regulation of IL‐10 in PRX‐1 knockdown cells and the resulting downregulation of proinflammatory cytokine production seem to involve the STAT3 pathway in macrophages. Thus, down‐regulation of PRX‐1 may contribute to the suppression of adverse effects caused by excessive activation of macrophages through affecting the STAT3 signaling pathway.</P>

Structures of <i>Staphylococcus aureus</i> peptide deformylase in complex with two classes of new inhibitors

Lee, Sang Jae,Lee, Seung&#x2010,Jae,Lee, Seung Kyu,Yoon, Hye&#x2010,Jin,Lee, Hyung Ho,Kim, Kyeong Kyu,Lee, Bong Jin,Lee, Byung Il,Suh, Se Won International Union of Crystallography 2012 Acta crystallographica. Section D, Biological crys Vol.68 No.7

<P>Peptide deformylase (PDF) catalyzes the removal of the formyl group from the N‐terminal methionine residue in newly synthesized polypeptides, which is an essential process in bacteria. Four new inhibitors of PDF that belong to two different classes, hydroxamate/pseudopeptide compounds [PMT387 (7a) and PMT497] and reverse‐hydroxamate/nonpeptide compounds [PMT1039 (15e) and PMT1067], have been developed. These compounds inhibited the growth of several pathogens involved in respiratory‐tract infections, such as <I>Streptococcus pneumoniae</I>, <I>Moraxella catarrhalis</I> and <I>Haemophilus influenzae</I>, and leading nosocomial pathogens such as <I>Staphylococcus aureus</I> and <I>Klebsiella pneumoniae</I> with a minimum inhibitory concentration (MIC) in the range 0.1–0.8 mg ml<SUP>−1</SUP>. Interestingly, the reverse‐hydroxamate/nonpeptide compounds showed a 250‐fold higher antimicrobial activity towards <I>S.?aureus</I>, although the four compounds showed similar <I>K</I><SUB>i</SUB> values against <I>S.?aureus</I> PDF enzymes, with <I>K</I><SUB>i</SUB> values in the 11–85 n<I>M</I> range. To provide a structural basis for the discovery of additional PDF inhibitors, the crystal structures of <I>S. aureus</I> PDF in complex with the four inhibitors were determined at resolutions of 1.90–2.30 Å. The inhibitor‐bound structures displayed distinct deviations depending on the inhibitor class. The distance between the Zn<SUP>2+</SUP> ion and the carbonyl O atom of the hydroxamate inhibitors (or the hydroxyl O atom of the reverse‐hydroxamate inhibitors) appears to be correlated to <I>S.?aureus</I> inhibition activity. The structural information reported in this study should aid in the discovery of new PDF inhibitors that can be used as novel antibacterial drugs.</P>

Inter‐domain handover scheme using an intermediate mobile access gateway for seamless service in vehicular networks

Lee, Kang&#x2010,Won,Seo, Won&#x2010,Kyeong,Cho, You&#x2010,Ze,Kim, Jong&#x2010,Woo,Park, Jin&#x2010,Soo,Moon, Byoung&#x2010,Sub John Wiley Sons, Ltd. 2010 International Journal of Communication Systems Vol.23 No.9

<P><B>Abstract</B></P>10.1002/dac.1076.abs<P>Current IP‐level mobility management protocols are unable to satisfy the stringent handover latency requirements for supporting real‐time multimedia services between different domains in a high‐speed vehicular environment. This paper proposes an inter‐domain handover scheme for Proxy Mobile IPv6 (PMIPv6) with a new network entity, called intermediate‐mobile access gateway (iMAG). The iMAG is located between the home and the foreign domains and is connected to both domains. The proposed scheme is a proactive handover approach that performs the inter‐domain L3 handover in advance before the inter‐domain L2 handover while the Mobile Node (MN) is still connected to the iMAG in the home domain. Therefore, the proposed scheme enables the inter‐domain handover latency to reduce as low as the intra‐domain handover latency. Numerical analysis and simulation results demonstrate that the proposed scheme is able to support seamless service continuity in inter‐domain handovers. Copyright © 2009 John Wiley & Sons, Ltd.</P>

Mycobacterial lipoprotein activates autophagy via TLR2/1/CD14 and a functional vitamin D receptor signalling

Shin, Dong&#x2010,Min,Yuk, Jae&#x2010,Min,Lee, Hye&#x2010,Mi,Lee, Sang&#x2010,Hee,Son, Ji Woong,Harding, Clifford V.,Kim, Jin&#x2010,Man,Modlin, Robert L.,Jo, Eun&#x2010,Kyeong Blackwell Publishing Ltd 2010 Cellular microbiology Vol.12 No.11

<P><B>Summary</B></P><P>In human monocytes, Toll‐like receptor (TLR) 2/1 activation leads to vitamin D3‐dependent antimycobacterial activities, but the molecular mechanisms by which TLR2/1 stimulation induces antimicrobial activities against mycobacteria remain unclear. Here we show that TLR2/1/CD14 stimulation by mycobacterial lipoprotein LpqH can robustly activate antibacterial autophagy through vitamin D receptor signalling activation and cathelicidin induction. We found that CCAAT/enhancer‐binding protein (C/EBP)‐β‐dependent induction of 25‐hydroxycholecalciferol‐1α‐hydroxylase (Cyp27b1) hydroxylase was critical for LpqH‐induced cathelicidin expression and autophagy. In addition, increases in intracellular calcium following AMP‐activated protein kinase (AMPK) activation played a crucial role in LpqH‐induced autophagy. Moreover, AMPK‐dependent p38 mitogen‐activated protein kinase (MAPK) activation was required for LpqH‐induced Cyp27b1 expression and autophagy activation. Collectively, these data suggest that TLR2/1/CD14‐Ca<SUP>2+</SUP>‐AMPK‐p38 MAPK pathways contribute to C/EBP‐β‐dependent expression of Cyp27b1 and cathelicidin, which played an essential role in LpqH‐induced autophagy. Furthermore, these results establish a previously uncharacterized signalling pathway of antimycobacterial host defence through a functional link of TLR2/1/CD14‐dependent sensing to the induction of autophagy.</P>

Sclerodermatous chronic graft‐versus‐host disease induced by host T‐cell‐mediated autoimmunity

Lee, You Jeong,Min, Hye Sook,Kang, Eun Ha,Park, Hyo Jin,Jeon, Yoon Kyung,Kim, Ju Hyun,Wu, Hong Gyun,Lee, Eun&#x2010,Bong,Park, Chung&#x2010,Gyu,Yoon, Sung&#x2010,Soo,Park, Seong Hoe,Jung, Kyeong Cheon Nature Publishing Group 2012 Immunology and cell biology Vol.90 No.3

<P>Despite a long‐standing hypothesis that chronic graft‐versus‐host disease (cGVHD) is an autoimmune disorder, most mouse models of cGVHD have been developed on the assumption that donor T cells are essential for its development. Here we show that cGVHD may be caused by autoreactive host T cells in mice that have been lethally irradiated and grafted with T‐cell‐depleted allogeneic bone marrow cells. In this chimera, host T cells derived from radioresistant intrathymic T‐cell precursors caused dermal fibrosis and periportal inflammation, without the requirement for donor T cells. The lack of host DCs within the thymus after high‐dose irradiation allowed autoreactive host T cells to escape thymic negative selection. Moreover, the homeostatic expansion of these T cells may augment their autoreactivity. These findings indicate that host T‐cell‐mediated cGVHD is an autoimmune process that occurs following the grafting of T‐cell‐depleted BM cells into hosts with functioning thymuses. We propose, based on the present data, that host T‐cell‐dependent autoimmunity is a potential mechanism by which cGVHD is induced.</P>

Evidence of carrier‐mediated transport in the penetration of donepezil into the rat brain

Kim, Mi&#x2010,Hwa,Maeng, Han&#x2010,Joo,Yu, Kyung&#x2010,Ha,Lee, Kyeong‐,Ryoon,Tsuruo, Takashi,Kim, Dae&#x2010,Duk,Shim, Chang&#x2010,Koo,Chung, Suk&#x2010,Jae Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of Pharmaceutical Sciences Vol.99 No.3

<P><B>Abstract</B></P><P>The objective of this study was to characterize the mechanism that controls the transport of donepezil into the brain. The apparent brain uptake clearance (CL<SUB>app,br</SUB>) was decreased as a function of the dose of donepezil, suggesting an involvement of a saturable transport process via transporter(s) in the penetration across the blood–brain barrier (BBB). Consistent with <I>in vivo</I> results, the uptake of substrates for organic cation transporters was significantly reduced by donepezil in both MBEC4 cells (i.e., a model for BBB) and HEK 293 cells expressing the transporters found in the brain, indicative of the involvement of organic cation transporters in the transport of the drug. Furthermore, donepezil transport was enhanced (<I>p</I> < 0.01) in HEK 293 cells expressing rOCNT1, rOCTN2, or rCHT1. The CL<SUB>app,br</SUB> was reduced up to 52.8% of the control in rats that had been pretreated with choline, while the CL<SUB>app,br</SUB> was unaffected with pretreatments with organic cations other than choline, suggesting that choline and donepezil share a common transport mechanism in the penetration across the BBB <I>in vivo</I>. Taken together, these observations suggest that the transport of donepezil across the BBB is mediated by organic cation transporters such as choline transport system(s). © 2009 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1548–1566, 2010</P>

Mussel‐Inspired Adhesive Binders for High‐Performance Silicon Nanoparticle Anodes in Lithium‐Ion Batteries

Ryou, Myung&#x2010,Hyun,Kim, Jangbae,Lee, Inhwa,Kim, Sunjin,Jeong, You Kyeong,Hong, Seonki,Ryu, Ji Hyun,Kim, Taek&#x2010,Soo,Park, Jung&#x2010,Ki,Lee, Haeshin,Choi, Jang Wook WILEY‐VCH Verlag 2013 Advanced Materials Vol.25 No.11

<P><B>Conjugation of mussel‐inspired catechol groups to various polymer backbones</B> results in materials suitable as silicon anode binders. The unique wetness‐resistant adhesion provided by the catechol groups allows the silicon nanoparticle electrodes to maintain their structure throughout the repeated volume expansion and shrinkage during lithiation cycling, thus facilitating substantially improved specific capacities and cycle lives of lithium‐ion batteries.</P>