• IMMUNE NETWORK
• /
• v.23 no.3
• /
• pp.29.1-29.23
• /
• 2023

Cholesterol (CL) is required for various biomolecular production processes, including those of cell membrane components. Therefore, to meet these needs, CL is converted into various derivatives. Among these derivatives is cholesterol sulfate (CS), a naturally produced CL derivative by the sulfotransferase family 2B1 (SULT2B1), which is widely present in human plasma. CS is involved in cell membrane stabilization, blood clotting, keratinocyte differentiation, and TCR nanocluster deformation. This study shows that treatment of T cells with CS resulted in the decreased surface expression of some surface T-cell proteins and reduced IL-2 release. Furthermore, T cells treated with CS significantly reduced lipid raft contents and membrane CLs. Surprisingly, using the electron microscope, we also observed that CS led to the disruption of T-cell microvilli, releasing small microvilli particles containing TCRs and other microvillar proteins. However, in vivo, T cells with CS showed aberrant migration to high endothelial venules and limited infiltrating splenic T-cell zones compared with the untreated T cells. Additionally, we observed significant alleviation of atopic dermatitis in mice injected with CS in the animal model. Based on these results, we conclude that CS is an immunosuppressive natural lipid that impairs TCR signaling by disrupting microvillar function in T cells, suggesting its usefulness as a therapeutic agent for alleviating T-cell-mediated hypersensitivity and a potential target for treating autoimmune diseases.

• Journal of Life Science
• /
• v.14 no.2
• /
• pp.315-319
• /
• 2004

For antibody development of human serine palmitoyltransferase (SPT, EC 2.3.1.50), SPTLC1 and SPTLC2 genes were subcloned in pRset vector and expressed in E. coli BL21 (DE3)pLys cells. Eucaryotic SPT is a membrane-bound heterodimer enzyme, while all other members are soluble homodimer enzymes. cDNA library were obtained from total RNA from human embryo kidney cell line, HEK293, using RT-PCR and PCR with specific primers was carried out for preparing SPTLC1 and SPTLC2 genes. pRset vector which can express hexahistidine-tag fusion protein was used and the DNA sequences of pRsetB/SPTLC1 and pRsetA/SPTLC2 were confirmed. Recombinant BL21 cells with SPTLC subunits were selected with LB plate containing ampicillin and chroramphenicol. SPTLC1 and SPTLC2 proteins were induced with 1 mM IPTG and seperated on 10% SDS-PAGE gel. Expressed proteins were confirmed by western blotting with His-tag antibody.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.81.2-82
• /
• 2003

Plants have evolved along with pathogens, and they have developed sophisticated defense systems against specific microorganisms to survive. G-protons are considered one of the upstream signaling components working as a key for the defense signal transduction pathway. For activation and inactivation of G-protein, GTP-biding proteins are involved. GTP -binding proteins are found in all organisms. Small GTP-binding proteins, having masses of 21 to 30kD, belong to a superfamily, often named the Ras supefamily because the founding members are encoded by human Ras genes initially discovered as cellular homologs of the viral ras oncogene. Members of this supefamily share several common structural features, including several guanine nucleotide binding domains and an effector binding domain. However, exhibiting a remarkable diversity in both structure and function. They are important molecular switches that cycle between the GDP-bound inactive form into the GTP-bound active form through GDP/GTP replacement. In addition, most GTP-binding proteins cycle between membrane-bound and cytosolic forms. such as the RAC family are cytosolic signal transduction proteins that often are involved in processing of extracellular stimuli. Plant RAC proteins are implicated in regulation of plant cell architecture secondary wall formation, meristem signaling, and defense against pathogens. But their molecular mechanisms and functions are not well known. We isolated a RacB homolog from rice to study its role of defense against pathogens. We introduced the constitutively active and the dominant negative forms of the GTP-hinging protein OsRacB into the wild type rice. The dominant negative foms are using two forms (full-sequence and specific RNA interference with RacB). Employing southern, and protein analysis, we examine to different things between the wild type and the transformed plant. And analyzing biolistic bombardment of onion epidermal cell with GFP-RacB fusion protein revealed association with the nucle.

• Biomolecules & Therapeutics
• /
• v.22 no.4
• /
• pp.275-281
• /
• 2014

Autophagy is a series of catabolic process mediating the bulk degradation of intracellular proteins and organelles through formation of a double-membrane vesicle, known as an autophagosome, and fusing with lysosome. Autophagy plays an important role of death-survival decisions in neuronal cells, which may influence to several neurodegenerative disorders including Parkinson's disease. Chebulagic acid, the major constituent of Terminalia chebula and Phyllanthus emblica, is a benzopyran tannin compound with various kinds of beneficial effects. This study was performed to investigate the autophagy enhancing effect of chebulagic acid on human neuroblastoma SH-SY5Y cell lines. We determined the effect of chebulagic acid on expression levels of autophagosome marker proteins such as, DOR/TP53INP2, Golgi-associated ATPase Enhancer of 16 kDa (GATE 16) and Light chain 3 II (LC3 II), as well as those of its upstream pathway proteins, AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and Beclin-1. All of those proteins were modulated by chebulagic acid treatment in a way of enhancing the autophagy. Additionally in our study, chebulagic acid also showed a protective effect against 1-methyl-4-phenylpyridinium ($MPP^+$) - induced cytotoxicity which mimics the pathological symptom of Parkinson's disease. This effect seems partially mediated by enhanced autophagy which increased the degradation of aggregated or misfolded proteins from cells. This study suggests that chebulagic acid is an attractive candidate as an autophagy-enhancing agent and therefore, it may provide a promising strategy to prevent or cure the diseases caused by accumulation of abnormal proteins including Parkinson's disease.

• Toxicological Research
• /
• v.19 no.3
• /
• pp.197-203
• /
• 2003

Apicidin, a histone-deacetylase inhibitor, has been successfully used to inhibit the growth of cancer cells. In this study, the apoptotic potential and mechanistic insights of apicidin were investigated in human myeloid leukemia U937 cells. Treatment of U937 cells with apicidin resulted in a decrease of cell viability with apoptotic characteristics, including chromatin condensation and ladder-pattern fragmentation of genomic DNA. Apicidin converted the procaspase-3 protease to catalytically active effector protease, resulting in subsequent cleavage of poly (ADP-ribose) polymerase (PARP) and inhibitor of caspase-activated deoxyribonuclease (ICAD). In addition, apicidin induced the activation of caspase-9 protease and the cytosolic release of mitochondrial cytochrome c with mitochon-drial membrane potential transition. Moreover, apicidin transiently increased the expression of Fas and Fas ligand proteins. Taken together, the results suggest that apicidin induces apoptosis of U937 cells through activation of intrinsic caspase cascades and Fas/FasL system with mitochondrial dysfunction.

• Animal cells and systems
• /
• v.13 no.3
• /
• pp.283-288
• /
• 2009

The ubiquitous plasma membrane $Na^+/H^+$ exchanger 1 (NHE1) is rapidly activated in response to various extracellular stimuli and maintains normal cytoplasmic pH. Yeast two-hybrid screening was used in order to identify proteins interacting with NHE1 using its cytoplasmic domain as a bait from HeLa cDNA library. One of the interacting cDNA clones was human Lactate dehydrogenase B (LDHB). In vitro translated LDHB was pulled down together with GST-NHE1.cd protein in the GST pull down assay, confirming the interaction in vitro. LDHB antibody immunoprecipitated endogenous LDHB together with NHE1 from H9c2 cells, validating cellular interaction between NHE1 and LDHB. Subsequent analysis revealed that the overexpression of LDHB increased intracellular PH, implying opening of the NHE1 transporter. Moreover, overexpression of LDHB activated caspase 3 and induced cell death, consistent with the expected phenotype of hyper-activation of NHE1. Collectively, our data indicate that LDHB modulates NHE1 activity via physical interaction.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.278.2-278.2
• /
• 2003

A column-switching semi-micro HPLC method with fluorescence detection was developed for the direct analysis of rebamipide in human plasma. Plasma was filtered through a 0.45 $\mu\textrm{m}$ membrane filter and 5 ${\mu}\ell$ of the filtrate was directly injected onto the pre-column. After elution of the plasma proteins to waste, the retained rebamipide and internal standard(ofloxacin) were transferred to a C18 semi-microcolumn (5$\mu\textrm{m}$, 150 ${\times}$2.0mm) where they were separated using acetonitrile-1.4％ acetic acid (40:60, v/v) as mobile phase. (omitted)

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.316.2-316.2
• /
• 2002

Manassantin B classified into dineolignans have been isolated from Saururus chinensis Manassantin B was found to induce apoptosis in human promyelocytic leukaemia HL -60 cells with characteristic apoptotic features like increase of nucleosomalladder. apoptotic body ormation. flipping of membrane phosphatidylserine. Manassantin B induced FAS and FAS ligand expression, and activated caspase 8 which cleaved bid to tbid in cytosol. The release of cytochrome c to sytosol was accompanied with decrease of bcl-2 protein and incresase of tbid and bax protein in mitochondria. Released xytochrome c activated caspase 9 and-3. but these effects were completely attenuated by the treatment of broad caspses ingibitor. Z-VAD fmk. These results indicate that manassatin B induce apoptosis through upregulation of FAS. caspase family and mitochondria-related proteins.

• Journal of Life Science
• /
• v.25 no.8
• /
• pp.849-860
• /
• 2015

The anti-cancer activities of Rhus verniciflua Stokes (GC), Ulmus davidiana var. japonica Nakai (UGP) and arsenium sublimatum (SS) extracts, which have been used Oriental medicine therapy for various diseases, were investigated. The treatment of GC, UGP and SS alone, and combined treatment with GC, UGP and SS did not affect the cell viability in the mouse normal cell lines (RAW 264.7 macrophages and C2C12 myoblasts). However, co-treatment with GC, UGP and SS markedly induces apoptosis in human gastric cancer AGS cells, but not in other various cancer cell lines (human lung cancer A549, colon cancer HCT116, liver cancer Hep3B and bladder T24 cells) as evidenced by formation of apoptotic bodies, chromatin condensation, and accumulation of annexin-V positive cells. Co-treatment with GC, UGP and SS effectively induced the expression levels of Fas and Fas ligand, and inhibited the levels IAP family proteins such as XIAP, cIAP-1 and survivin, and anti-apoptotic Bcl-xL proteins compared with treatment with either agent alone. Combined treatment also significantly induced the loss of mitochondrial membrane potential, which was associated with the activation of caspases (-3, -8, and -9) and degradation of poly (ADP-ribose) polymerase. However, the cytotoxic effects induced by co-treatment with GC, UGP and SS were significantly attenuated by pan-caspases inhibitor, z-VAD-fmk, indicating an important role for caspases. These results indicated that the caspases were key regulators of apoptosis in response to co-treatment of GC, UGP and SS in human gastric cancer AGS cells and further studies will be needed to identify the active compounds.

• Archives of Pharmacal Research
• /
• v.28 no.4
• /
• pp.421-432
• /
• 2005

In order to understand the renal reabsorption mechanism of neutral amino acids via amino acid transporters, we have isolated human L-type amino acid transporter 2 (hLAT2) and human T-type amino acid transporter 1 (hTAT1) in human, then, we have examined and compared the gene structures, the functional characterizations and the localization in human kidney. Northern blot analysis showed that hLAT2 mRNA was expressed at high levels in the heart, brain, placenta, kidney, spleen, prostate, testis, ovary, lymph node and the fetal liver. The hTAT1 mRNA was detected at high levels in the heart, placenta, liver, skeletal muscle, kidney, pancreas, spleen, thymus and prostate. Immunohistochemical analysis on the human kidney revealed that the hLAT2 and hTAT1 proteins coexist in the basolateral membrane of the renal proximal tubules. The hLAT2 transports all neutral amino acids and hTAT1 transports aromatic amino acids. The basolateral location of the hLAT2 and hTAT1 proteins in the renal proximal tubule as well as the amino acid transport activity of hLAT2 and hTAT1 suggests that these transporters contribute to the renal reabsorption of neutral and aromatic amino acids in the basolateral domain of epithelial proximal tubule cells, respectively. Therefore, LAT2 and TAT1 play essential roles in the reabsorption of neutral amino acids from the epithelial cells to the blood stream in the kidney. Because LAT2 and TAT1 are essential to the efficient absorption of neutral amino acids from the kidney, their defects might be involved in the pathogenesis of disorders caused by a disruption in amino acid absorption such as blue diaper syndrome.