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1.
Localization of Idd11 using NOD congenic mouse strains: elimination of Slc9a1 as a candidate gene 总被引:5,自引:0,他引:5
Type 1 diabetes is a multigenic autoimmune disease, the genetic basis for which is perhaps best characterized in the nonobese
diabetic (NOD) mouse model. We previously located a NOD diabetes susceptibility locus, designated Idd11, on mouse Chromosome (Chr) 4 by analyzing diabetic backcross mice produced after crossing NOD/Lt with the nondiabetic resistant strain C57BL/6 (B6) strain. In order to confirm Idd11 and further refine its location, three NOD congenic mouse strains with different B6 derived intervals within Chr 4 were generated.
Two of the congenic strains had a significant decrease in the cumulative incidence of diabetes compared with NOD/Lt control
mice. The third NOD congenic strain, containing a B6 interval surrounding the Slc9a1 locus, was not protected against diabetes. These results define a new distal boundary for Idd11 and eliminate the Slc9a1 gene as a candidate. The Idd11 locus has now been definitively mapped to a 13cM interval on mouse Chr 4.
Received: 15 May 1999 / Revised: 25 September 1999 相似文献
2.
β-1,4-galactosyltransferase I (β-1,4-GalT I) plays an important role in the synthesis of the backbone structure of adhesion molecules involved in leukocyte–endothelial
cell interaction. The expression of β-1,4-GalT I mRNA increased in primary human endothelial cells after exposure to tumor necrosis factor-α (TNF-α). In the central nervous system (CNS), astrocytes play a pivotal role in immunity as immunocompetent cells by secreting
cytokines and inflammatory mediators, there are two types of astrocytes. Type-1 astrocytes can secrete TNF-α when stimulated
with Lipopolysaccharide (LPS), while the responses of type-2 astrocytes during inflammation are unknown. So we examined the
expression change of β-1,4-GalT I mRNA in type-2 astrocytes after exposure to TNF-α and LPS. Real-time PCR showed that TNF-α or LPS affected β-1,4-GalT I mRNA expression in a time- and dose-dependent manner. RT-PCR analysis revealed that TNFR1 and TNFR2 were present
in normal untreated type-2 astrocytes, and that TNF-α, TNFR1 and TNFR2 increased in type-2 astrocytes after exposure to TNF-α or LPS. Immunocytochemistry showed that TNFR1 was
expressed in the cytoplasm, nucleus and processes of normal untreated type-2 astrocytes, and distributed mainly in the cytoplasm
and processes after exposure to LPS. TNFR2 was mainly expressed in the nucleus of normal untreated type-2 astrocytes, and
distributed mainly in the processes of type-2 astrocytes after exposure to LPS. Both anti-TNFR1 and anti-TNFR2 antibodies
suppressed β-1,4-GalT I mRNA expression induced by TNF-α or LPS. From these results, we conclude that TNF-α signaling via both TNFR1 and TNFR2 translocated from nucleus to cytoplasm or processes is sufficient to induce β-1,4-GalT I mRNA. In addition, we observed that not only exogenous TNF-α but also TNF-α produced by type-2 astrocytes affected β-1,4-GalT I mRNA production in type-2 astrocytes. These results suggest that an autocrine loop involving TNF-α contributes
to the production of β-1,4-GalT I mRNA in response to inflammation.
Chunlin Xia is the co-first author. 相似文献
3.
Joëlle Morin Christian Boitard David Vallois Philip Avner Ute Christine Rogner 《Mammalian genome》2006,17(11):1105-1112
In the nonobese diabetes mouse, the murine type 1 diabetes susceptibility locus Idd20 interacts genetically with the diabetes resistance locus Idd19. Both Idds are located on distal mouse Chromosome 6, and previous studies on NOD.C3H congenic strains have shown that C3H alleles at
Idd20 can suppress the disease-promoting effects of C3H alleles at Idd19 in both spontaneous and cyclophosphamide-induced diabetes. In this article we present the construction of novel congenic
strains which, while maintaining the C3H alleles at Idd19, have allowed the candidate interval of Idd20 to be reduced from 4 to 1.8 cM. The analysis of these strains shows that Idd20 controls the progression of insulitis. Idd20 also increases the suppressive but not the pathogenic activity of splenocytes in diabetes transfer experiments. Our results
suggest that the two Chromosome 6 susceptibility loci, Idd6 and Idd20, interact with the resistance locus Idd19 by regulating the activity of suppressor cells in the peripheral immune system. 相似文献
4.
Anti-Smith (anti-Sm) autoantibodies are directed to proteins in the small-nuclear ribonucleoprotein (snRNP) family and are
considered specific for systemic lupus erythematosus (SLE) in both humans and mice. We previously established that NOD.c3c4
mice, carrying B6 and B10 congenic segments from chromosomes 3 to 4 on an nonobese diabetic (NOD) background, and NOD.Idd9R28 mice, carrying a B10 segment on c4 alone, developed significant penetrance of anti-Sm antibody production. Here we determine
autoantibody incidence in additional NOD.Idd9 congenic strains and use a congenic mapping approach to narrow the interval necessary for enhanced autoantibody production
to a ∼5.6-Mb region containing insulin-dependent diabetes (Idd)9.3. The Idd9.3 interval contains the candidate molecule cluster of differentiation (CD)137, which is a member of the tumor necrosis factor
(TNF) receptor superfamily, functions as an inducible costimulator of T cells, and controls T–B interactions. The NOD and
B10 CD137 alleles have sequence polymorphisms and different functional effects on T cells; the NOD CD137 allele mediates weaker T cell proliferative responses and decreased interleukin (IL)-2 production after CD137-mediated costimulation.
Our work establishes CD137 as a candidate gene for control of autoantibody production in NOD.Idd9.3 congenic mice. 相似文献
5.
Species, varieties, and hybrids of Vitis are differently susceptible to feeding by the aphid Daktulosphaira vitifoliae (Fitch) (Hemiptera: Phylloxeridae). The differing levels of susceptibility were examined in Vitis riparia × V. rupestris cv. C-3309, V. vinifera × V. labrusca cv. Weiβe Amerikaner, and V. vinifera cv. Portugieser Weiβherbst by characterizing early subcellular changes to aphid feeding. We examined the fifth and sixth
layers of mesophyll parenchyma between 3 and 48 h after introducing neonate nymphs of D. vitifoliae on to those leaves. In the susceptible variety C-3309, activated and metaplasied cells appeared in 3–6 h of feeding by D. vitifoliae and developed into nutritive tissue in the next 24–48 h. On the contrary, cells of the resistant variety Portugieser Weiβherbst
accumulated phenolic materials indicating a hypersensitive response; those of Weiβe Amerikaner showed a mixed response of
developing a nutritive tissue and a concurrent accumulation of phenolic materials especially in cells away from the nutritive
tissue, indicating that this hybrid could tolerate D. vitifoliae. Galls developed on the leaves of C-3309 in 21 days, whereas no gall development occurred on the leaves of Portugieser Weiβherbst
and Weiβe Amerikaner. D. vitifoliae nymphs introduced on the leaves of Portugieser Weiβherbst died in 3–4 days, whereas on the leaves of Weiβe Amerikaner, nymphs
lived up to 21 days. Thus early subcellular changes in leaf tissues determined the feeding activity of nymphs on leaves and
the susceptibility of plants to insect feeding.
Zusammenfassung Bl?tter verschiedener Rebsorten reagieren unterschiedlich auf den Befall mit der Reblaus Daktulosphaira vitifoliae (Fitch). Hier wurde die Reaktion der Sorten Vitis riparia × V. rupestris cv. C-3309, V. vinifera × V. labrusca cv. Weiβe Amerikaner und V. vinifera cv. Portugieser Weiβherbst (kurz: C-3309, Weiβe Amerikaner und Portugieser Weiβherbst) verglichen, um die unterschiedliche Empfindlichkeit zu verstehen. Dazu wurden frühe subzellul?re Ver?nderungen der Blattgewebe in aseptischen Dualkulturen aus Vitis und D. vitifoliae charakterisiert. Da die Stechborsten der jungen Nymphen von D. vitifoliae bis in die fünfte oder sechste Mesophyllschicht von C-3309 eindringen, wurden Zellen dieser Schichten bei allen drei Rebsorten 3–48 Stunden nach Zugabe der Nymphen beobachtet. Bei der Sorte C-3309 erfolgte eine Differenzierung von aktivierten und metaplasierten Zellen 3–6 Stunden nach dem Befall. In den folgenden 24–48 Stunden entwickelten sich diese Zellen zu einem N?hrgewebe; somit erfolgte eine kompatible Reaktion. Im Gegensatz dazu zeigten die Zellen der Sorte Portugieser Weiβherbst eine hypersensitive Reaktion mit Akkumulation phenolischer Verbindungen. Zellen der Sorte Weiβe Amerikaner reagierten sowohl mit der Bildung von N?hrzellen als auch mit der Akkumulation phenolischer Verbindungen ausserhalb der N?hrzellen; dies ist ein Zeichen für Toleranz. Die Entwicklung typischer Gallen erfolgte in 21 Tagen ausschliesslich an den Bl?ttern der Sorte C-3309. An Portugieser Weiβherbst starben die Nymphen innerhalb von 3–4 Tagen ab, an Bl?ttern von Weiβe Amerikaner überlebten sie bis zum 21 Tag, ohne dass eine Gallbildung erfolgte. Die frühen subzellul?re Ver?nderungen der Blattgewebe bestimmten somit die Frasst?tigkeit der Nymphen und die Empfindlichkeit der drei Rebsorten auf den Insektenbefall.相似文献
6.
Mary L García-Cazarín Jennifer L Smith Kyle A Olszewski Dan F McCune Linda A Simmerman Robert W Hadley Susan D Kraner Michael T Piascik 《Journal of molecular signaling》2008,3(1):1-9
Background
We have previously shown that c-FLIPL is a more potent inhibitor than c-FLIPS of Fas ligand-induced apoptosis and that c-FLIPL physically binds to Daxx, an alternative Fas-signaling adaptor. Here we examined whether c-FLIPS effectively inhibits TNFR1-mediated apoptosis and triggers JNK activation through its interaction with TRAF2.Results
Some cancer cell lines, such as DU145, AGS, and PC3, have higher levels of c-FLIPS than other cell lines, such as SNU-719 and T24. The expression of c-FLIPS correlated with the susceptibility to TNFR1-mediated apoptosis. In contrast to DU145 and PC3, which are resistant to TNFR1-mediated apoptosis, T24 and SNU719 were sensitive to TNF-α treatment. To address the role of c-FLIPS in TNFR1-mediated apoptosis, we examined the molecular interaction between c-FLIPS and TRAF2. As expected, western blot analysis revealed that TRAF2 antibody immunoprecipitated a greater amount of c-FLIPS than c-FLIPL. Also, we measured the involvement of c-FLIPS in TNF-α-induced JNK activation and apoptosis by comparing these in TNF-α-resistant and TNF-α-sensitive cell lines. Treatment with TNF-α increased the phosphorylated JNK level in SNU719 and T24 cells, whereas DU145 and AGS cells were resistant to TNF-α-mediated apoptosis.Conclusion
We now report that the short form of c-FLIPS is a more efficient inhibitor of TNF-receptor 1-mediated apoptosis signaling than the long form of the protein. 相似文献7.
Type 1 diabetes (T1D) results from autoimmune destruction of the insulin-producing β-cells in the pancreatic islets of Langerhans
by autoreactive T helper 1 (Th1) cells characterized by their cytokine secretory products, interleukin-2 (IL-2) and interferon
γ (IFNγ). Th1-type cytokines (IL-2 and IFNγ) correlate with T1D, whereas Th2 (IL-4 and IL-10), Th3 (transforming growth factor
beta [TGFβ]), and T regulatory cell-type cytokines (IL-10 and TGFβ) correlate with protection from T1D. Paradoxically, however,
administrations of Th1-type cytokines (IL-2 and IFNγ) and immunotherapies that induce Th1-type cytokine responses actually
prevent T1D, at least in animal models. Therefore, immunotherapies that inhibit IL-2 production/action will block Th1 cell/cytokine-driven
effector mechanisms of pancreatic islet β-cell destruction; however, anti-IL-2 therapy will not allow immune tolerance to
be established. In contrast, immunotherapies that increase IL-2 production/action may correct an immunodeficiency in IL-2
production that appears to underlie the autoimmunity of T1D, thereby restoring immune tolerance to islet β-cells and prevention
of T1D. 相似文献
8.
Gyorgy Szabadkai Michael R. Duchen 《Apoptosis : an international journal on programmed cell death》2009,14(12):1405-1423
Mitochondrial dysfunction plays a role in the pathogenesis of a wide range of diseases that involve disordered cellular fuel
metabolism and survival/death pathways, including neurodegenerative diseases, cancer and diabetes. Cytokine, virus recognition
and cellular stress pathways converging on mitochondria cause apoptotic and/or necrotic cell death of β-cells in type-1 diabetes. Moreover, since mitochondria generate crucial metabolic signals for glucose stimulated insulin secretion (GSIS),
mitochondrial dysfunction underlies both the functional derangement of GSIS and (over-nutrition) stress-induced apoptotic/necrotic
β-cell death, hallmarks of type-2 diabetes. The apparently distinct mechanisms governing β-cell life/death decisions during the development of diabetes provide
a remarkable example where remote metabolic, immune and stress signalling
meet with mitochondria mediated apoptotic/necrotic death pathways to determine the fate of the β-cell. We summarize the main findings supporting such a pivotal role of mitochondria in β-cell
death in the context of current trends in diabetes research. 相似文献
9.
Jing Li Weiping Yu Richa Tiwary Sook-Kyung Park Ailian Xiong Bob G Sanders Kimberly Kline 《Cancer cell international》2010,10(1):40
Background
Alpha-tocopherol ether-linked acetic acid (α-TEA), an analog of vitamin E (RRR-alpha-tocopherol), is a potent and selective apoptosis-inducing agent for human cancer cells in vivo and in vitro. α-TEA induces apoptosis via activation of extrinsic death receptors Fas (CD95) and DR5, JNK/p73/Noxa pathways, and suppression of anti-apoptotic mediators Akt, ERK, c-FLIP and survivin in breast, ovarian and prostate cancer cells. 相似文献10.
Gaurav Verma Malabika Datta 《Apoptosis : an international journal on programmed cell death》2010,15(7):864-876
The proinflammatory cytokine, IL-1β (Interleukin-1β) is a significant determinant of pancreatic apoptosis and cell death that
are common characteristics during diabetes. Using human derived pancreatic MIA PaCa-2 cells, we describe one of the underlying
molecular mechanisms behind this observation. Incubation of these cells with IL-1β at doses from 0.5 to 3.0 ng/ml caused significant
cell death at 36 h. This was accompanied with marked increases in JNK and p38 phosphorylation together with increased levels
of the endoplasmic reticulum (ER) stress markers, namely BiP, CHOP, GADD34, ATF4 and sXBP1. IL-1β also led to increased phosphorylation
of eIF2α and all these events could be prevented by pretreatment with the JNK inhibitor, SP600125. A time course study indicated
that while IL-1β mediated JNK phosphorylation was induced as early as 2 h of IL-1β treatment, induction of the ER stress markers
was evident at later time points. IL-1β stimulated JNK phosphorylation was observed even in the presence of the ER stress
inhibitor, 4-phenyl butyrate and the decrease in cell viability was significantly prevented in the presence of the JNK inhibitor.
All these suggest that JNK activation is a pre-requisite for ER stress induction and cell death. Reports till date have consistently
demonstrated JNK activation as a consequence of ER stress induction by IL-1β in the pancreas. We show here for the first time
that the activation of JNK by IL-1β is a prelude to the subsequent induction of ER stress and cell death. These therefore
suggest that the JNK-ER stress axis is critical in deciding the decreased survival status by IL-1β in MIA PaCa-2 cells. 相似文献
11.
Stefan U. Weber Andreas Koch Jens Kankeleit Jens-Christian Schewe Ullrich Siekmann Frank Stüber Andreas Hoeft Stefan Schröder 《Apoptosis : an international journal on programmed cell death》2009,14(1):97-107
During therapeutic hyperbaric oxygenation lymphocytes are exposed to high partial pressures of oxygen. This study aimed to
analyze the mechanism of apoptosis induction by hyperbaric oxygen. For intervals of 0.5–4 h Jurkat-T-cells were exposed to
ambient air or oxygen atmospheres at 1–3 absolute atmospheres. Apoptosis was analyzed by phosphatidylserine externalization,
caspase-3 activation and DNA-fragmentation using flow cytometry. Apoptosis was already induced after 30 min of hyperbaric
oxygenation (HBO, P < 0.05). The death receptor Fas was downregulated. Inhibition of caspase-9 but not caspase-8 blocked apoptosis induction
by HBO. Hyperbaric oxygen caused a loss of mitochondrial membrane potential and caspase-9 induction. The mitochondrial pro-survival
protein Bcl-2 was upregulated, and antagonizing Bcl-2 function potentiated apoptosis induction by HBO. In conclusion, a single
exposure to hyperbaric oxygenation induces lymphocyte apoptosis by a mitochondrial and not a Fas-related mechanism. Regulation
of Fas and Bcl-2 may be regarded as protective measures of the cell in response to hyperbaric oxygen. 相似文献
12.
Ulrike Resch Angélica Cuapio Caterina Sturtzel Erhard Hofer Rainer de Martin Yvonne M. Holper-Schichl 《The Journal of biological chemistry》2014,289(36):25088-25100
Binding of TNF to its receptor (TNFR1) elicits the spatiotemporal assembly of two signaling complexes that coordinate the balance between cell survival and cell death. We have shown previously that, following TNF treatment, the mRNA decay protein tristetraprolin (TTP) is Lys-63-polyubiquitinated by TNF receptor-associated factor 2 (TRAF2), suggesting a regulatory role in TNFR signaling. Here we demonstrate that TTP interacts with TNFR1 in a TRAF2-dependent manner, thereby initiating the MEKK1/MKK4-dependent activation of JNK activities. This regulatory function toward JNK activation but not NF-κB activation depends on lysine 105 of TTP, which we identified as the corresponding TRAF2 ubiquitination site. Disabling TTP polyubiquitination results in enhanced TNF-induced apoptosis in cervical cancer cells. Together, we uncover a novel aspect of TNFR1 signaling where TTP, in alliance with TRAF2, acts as a balancer of JNK-mediated cell survival versus death. 相似文献
13.
Effect of interferon-γ on the susceptibility to Fas (CD95/APO-1)-mediated cell death in human hepatoma cells 总被引:9,自引:0,他引:9
Shin EC Shin WC Choi Y Kim H Park JH Kim SJ 《Cancer immunology, immunotherapy : CII》2001,50(1):23-30
Many tumors, including hepatocellular carcinomas (HCCs), resist Fas-mediated cell death, which is one of the effector mechanisms
in the host's anti-tumor response; however, this resistance can be abolished by interferon-γ (IFN-γ). IFN-γ may sensitize
Fas-mediated cell death in several ways, but the exact mechanism in HCCs is uncertain. In this study, we thoroughly investigated
the effect of IFN-γ on the susceptibility of one human normal liver cell line and 12 HCC cell lines to Fas-mediated cell death.
We also investigated the effect of IFN-γ on the expression of various apoptosis-related genes such as the Fas/TNF-related
genes, the bcl-2 family, and the caspase family of genes. Although most cell lines showed considerable constitutive expression of Fas, all
tested cell lines resisted Fas-mediated cell death without IFN-γ. When cells were pretreated with IFN-γ, only three cell lines
were made significantly susceptible to Fas-mediated cell death (SNU-354, SNU-387 and SNU-423); the other 10 cell lines were
not affected. IFN-γ increased the mRNA expression of Fas, TRAIL and caspase-1, and surface Fas was also increased. The strongly
sensitized cell lines (SNU-354, SNU-387 and SNU-423) showed a particularly potent increment in surface Fas after IFN-γ treatment
(increase in surface Fas >1.7-fold). This result enabled us to conclude that a potent increment of surface Fas expression
is a major sensitizing mechanism of IFN-γ. We conclude that IFN-γ cannot play a sensitizing role in most HCC cell lines and
that IFN-γ makes HCC cells susceptible to Fas-mediated cell death through a marked up-regulation of surface Fas in some HCC
cells.
Received: 3 August 2000 / Accepted: 24 November 2000 相似文献
14.
15.
The effects of trans fatty acids, elaidic acid (trans-9, C18:1) and linoelaidic acid (trans-9, trans-12 C18:2), at 20 or 40 μM
in nerve growth factor differentiated PC12 cells with or without beta-amyloid peptide (Aβ) were examined. Elaidic acid treatment
alone did not affect cell viability and oxidative injury associated markers (P > 0.05). However, co-treatments of elaidic acid and Aβ led to more reduction in mitochondrial membrane potential (MMP) and
Na+-K+-ATPase activity, and more increase in DNA fragmentation and 8-hydroxydeoxyguanosine (8-OHdG) production than Aβ treatment
alone (P < 0.05). Linoelaidic acid alone exhibited apoptotic and oxidative effects in cells via decreasing MMP and Na+-K+-ATPase activity, increasing reactive oxygen species (ROS) level, lowering glutathione content and glutathione peroxidase
(GPX) activity (P < 0.05). The co-treatments of linoelaidic acid with Aβ further enhanced oxidative damage via enhancing the generation of
ROS, nitrite oxide and 8-OHdG, elevating caspase-3, caspase-8 and nitric oxide synthase activities, as well as declining GPX,
catalase and superoxide dismutase activities (P < 0.05). These results suggested that the interaction of linoelaidic acid and Aβ promoted oxidative stress and impaired mitochondrial
functions in neuronal cells. 相似文献
16.
Alsaba F Raja Furqan Ali Inshad A Khan Abdul S Shawl Daljit S Arora Bhahwal A Shah Subhash C Taneja 《BMC microbiology》2011,11(1):54
Background
Boswellic acids are pentacyclic triterpenes, which are produced in plants belonging to the genus Boswellia. Boswellic acids appear in the resin exudates of the plant and it makes up 25-35% of the resin. β-boswellic acid, 11-keto-β-boswellic acid and acetyl-11-keto-β-boswellic acid have been implicated in apoptosis of cancer cells, particularly that of brain tumors and cells affected by leukemia or colon cancer. These molecules are also associated with potent antimicrobial activities. The present study describes the antimicrobial activities of boswellic acid molecules against 112 pathogenic bacterial isolates including ATCC strains. Acetyl-11-keto-β-boswellic acid (AKBA), which exhibited the most potent antibacterial activity, was further evaluated in time kill studies, postantibiotic effect (PAE) and biofilm susceptibility assay. The mechanism of action of AKBA was investigated by propidium iodide uptake, leakage of 260 and 280 nm absorbing material assays. 相似文献17.
1,25-dihydroxyvitamin D3 protects human pancreatic islets against cytokine-induced apoptosis via down-regulation of the fas receptor 总被引:4,自引:0,他引:4
Riachy R Vandewalle B Moerman E Belaich S Lukowiak B Gmyr V Muharram G Kerr Conte J Pattou F 《Apoptosis : an international journal on programmed cell death》2006,11(2):151-159
Beta cell loss occurs at the onset of type 1 diabetes and after islet graft. It results from the dysfunction and destruction
of beta cells mainly achieved by apoptosis. One of the mediators believed to be involved in beta cell apoptosis is Fas, a
transmembrane cell surface receptor transducing an apoptotic death signal and contributing to the pathogenesis of several
autoimmune diseases. Fas expression is particularly induced in beta cells by inflammatory cytokines secreted by islet-infiltrating
mononuclear cells and makes cells susceptible to apoptosis by interaction with Fas-ligand expressing cells. We have previously
demonstrated that 1,25 (OH)2 D3, the active metabolite of vitamin D, known to exhibit immunomodulatory properties and prevent the development of type 1 diabetes
in NOD mice, is efficient against apoptosis induced by cytokines in human pancreatic islets in vitro. The effects were mainly
mediated by the inactivation of NF-kappa-B. In this study we demonstrated that 1,25 (OH)2 D3 was also able to counteract cytokine-induced Fas expression in human islets both at the mRNA and protein levels. These results
were reinforced by our microarray analysis highlighting the beneficial effects of 1,25 (OH)2 D3 on death signals induced by Fas activation. Our results provides additional evidence that 1,25 (OH)2 D3 may be an interesting tool to help prevent the onset of type 1 diabetes and improve islet graft survival. 相似文献
18.
Novel oligosaccharide has suppressive activity against human leukemia cell proliferation 总被引:1,自引:0,他引:1
Hosomi O Misawa Y Takeya A Matahira Y Sugahara K Kubohara Y Yamakura F Kudo S 《Glycoconjugate journal》2009,26(2):189-198
Various oligosaccharides containing galactose(s) and one glucosamine (or N-acetylglucosamine) residues with β1–4, α1–6 and β1–6 glycosidic bond were synthesized; Galβ1–4GlcNH2, Galα1–6GlcNH2, Galα1–6GlcNAc, Galβ1–6GlcNH2, Galβ1–4Galβ1–4GlcNH2 and Galβ1–4Galβ1–4GlcNAc. Galα1–6GlcNH2 (MelNH2) and glucosamine (GlcNH2) had a suppressive effect on the proliferation of K562 cells, but none of the other saccharides tested containing GlcNAc
showed this effect. On the other hand, the proliferation of the human normal umbilical cord fibroblast was suppressed by none
of the saccharides other than GlcNH2. Adding Galα1–6GlcNH2 or glucosamine to the culture of K562 cell, the cell number decreased strikingly after 72 h. Staining the remaining cells
with Cellstain Hoechst 33258, chromatin aggregation was found in many cells, indicating the occurrence of cell death. Furthermore,
all of the cells were stained with Galα1–6GlcNH-FITC (MelNH-FITC). Neither the control cells nor the cells incubated with
glucosamine were stained. On the other hand, when GlcNH-FITC was also added to cell cultures, some of them incubated with
Galα1–6GlcNH2 were stained. The difference in the stainability of the K562 cells by Galα1–6GlcNH-FITC and GlcNH-FITC suggests that the
intake of Galα1–6GlcNH2 and the cell death induced by this saccharide is not same as those of glucosamine. The isolation of the Galα1–6GlcNH2 binding protein was performed by affinity chromatography (melibiose-agarose) and LC-MS/MS, and we identified the human heterogeneous
ribonucleoprotein (hnRNP) A1 (34.3 kDa) isoform protein (30.8 kDa). The hnRNP A1 protein was also detected from the eluate(s)
of the MelNH-agarose column by the immunological method (anti-hnRNP-A1 and HRP-labeled anti-mouse IgG (γ) antibodies). 相似文献
19.
Daniela Siegmund Juliane Kums Martin Ehrenschwender Harald Wajant 《Cell death & disease》2016,7(9):e2375
Macrophages express TNFR1 as well as TNFR2 and are also major producers of tumor necrosis factor (TNF), especially upon contact with pathogen-associated molecular patterns. Consequently, TNF not only acts as a macrophage-derived effector molecule but also regulates the activity and viability of macrophages. Here, we investigated the individual contribution of TNFR1 and TNFR2 to TNF-induced cell death in macrophages. Exclusive stimulation of TNFR1 showed no cytotoxic effect whereas selective stimulation of TNFR2 displayed mild cytotoxicity. Intriguingly, the latter was strongly enhanced by the caspase inhibitor zVAD-fmk. The strong cytotoxic activity of TNFR2 in the presence of zVAD-fmk was reversed by necrostatin-1, indicating necroptotic cell death. TNFR1- and TNF-deficient macrophages turned out to be resistant against TNFR2-induced cell death. In addition, the cIAP-depleting SMAC mimetic BV6 also enforced TNF/TNFR1-mediated necroptotic cell death in the presence of zVAD-fmk. In sum, our data suggest a model in which TNFR2 sensitizes macrophages for endogenous TNF-induced TNFR1-mediated necroptosis by the known ability of TNFR2 to interfere with the survival activity of TRAF2-cIAP1/2 complexes.Tumor necrosis factor (TNF) is a pleiotropic cytokine that occurs as a type II transmembrane protein but can be released from the plasma membrane by proteolytic processing.1 Membrane-bound and soluble TNF both contain the characteristic carboxy-terminal TNF homology domain, which is responsible for self-assembly into trimeric molecules and receptor binding. Membrane-bound and soluble TNF strongly interact with two receptors, TNFR1 and TNFR2, but the two forms of TNF are differentially effective in receptor activation.1 Whereas membrane-bound TNF activates TNFR1 and TNFR2 efficiently, soluble TNF is sufficient for TNFR1 activation but largely inactive upon binding to TNFR2. TNFR1 belongs to the death receptor subgroup of the TNF receptor family and can trigger apoptosis and necroptosis.2, 3, 4 However, cell death induction by TNFR1 is typically efficiently antagonized by concomitant activation of the cytoprotective classical NFκB pathway and/or ubiquitous expression of anti-apoptotic proteins.1, 2 The latter involve FLIP proteins which generally inhibit death receptor-induced caspase-8 activation but also complexes containing TRAF2, cIAP1 and cIAP2 which specifically interfere with caspase-8 activation in context of TNFR1 signaling.2, 3, 4 Worth mentioning, TRAF2-cIAP1/2 complexes also mediate K63-linked ubiquitination of RIP1 in the TNFR1 signaling complex, thereby facilitating TNFR1-mediated activation of the classical NFκB pathway. Indeed, TNFR1 signaling is predominantly pro-inflammatory as TNFR1-induced cell death is blocked as long as the aforementioned protective mechanisms are not impaired.In contrast to TNFR1, TNFR2 contains no cytoplasmic death domain. Upon ligand binding, TNFR2 recruits TRAF2 and various TRAF2-associated proteins, such as TRAF1, cIAP1 and cIAP2, but also interacts with other signaling proteins independently of TRAF2.1, 5 TNFR2 activation has been linked to a variety of immune regulatory functions, which, in contrast to the activities of TNFR1, often result in anti-inflammatory effects.6Murine models shed light on the complex interplay of the TNFR1–TNFR2 system in vivo, demonstrating additive, synergistic or even antagonistic effects. At the cellular level, several mechanisms for the cross-talk between TNFR1 and TNFR2 have been identified.1 Besides the obvious competition for ligand binding, TNFR1 and TNFR2 can induce, for example, autocrine TNF production in a cell type-specific manner.1 In context of TNFR1 activation by soluble TNF, subsequent induction of membrane-bound TNF results in costimulation of TNFR2, thereby converting the initially transient activation into sustained autocrine signaling. In addition, TNFR1 and TNFR2 compete for the cytoplasmic pool of TRAF2–cIAP1/2 complexes. By depletion and/or degradation of TRAF2, TNFR2 is capable to modulate TNFR1 signaling.1 Moreover, TNFR2 but not TNFR1, stimulates the alternative NFκB pathway by triggering proteolytic processing of the inactive p100/RelB dimers into active p52/RelB NFκB complexes.7 Notably, TNFR2-induced alternative NFκB signaling can be enhanced by TNFR1-mediated induction of p100 and RelB expression via the classical NFκB pathway.7In macrophages, the complexity of the TNF-TNFR1/2 system is especially relevant. Macrophages on one hand co-express TNFR1 and TNFR2 and are on the other hand a pathophysiologically important source of TNF, for example, in response to a variety of pathogen-associated molecular patterns (PAMPs). TNF not only acts as a macrophage-derived effector molecule, but in an autocrine fashion also controls macrophage activation and survival, as seen for example during infection with mycobacteria.8, 9, 10, 11, 12, 13, 14, 15, 16, 17 However, the molecular mechanisms of TNF-induced cell death in macrophages are incompletely understood and were, therefore addressed in our study. Using macrophages genetically deficient for TNFR1, TNFR2 or TNF together with TNFR1- and TNFR2-specific TNF variants, we show that TNFR2 activation sensitizes macrophages for TNFR1-mediated necroptosis triggered by autocrine produced TNF and provide evidence that this is related to TNFR2-induced depletion/degradation of TRAF2-cIAP1/2 complexes. 相似文献