共查询到20条相似文献,搜索用时 78 毫秒
1.
Hiroyuki Kamiguchi Kazunari Yoshida Hirooki Wakamoto Makoto Inaba Hikaru Sasaki Mitsuhiro Otani Shigeo Toya 《Neurochemical research》1996,21(6):701-706
Cytokines such as interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and epidermal growth factor (EGF) are probable factors
responsible for up-regulation of basic fibroblast growth factor (bFGF) expression in reactive astrocytes following brain damage,
however the effect of these cytokines on the expression of each bFGF-isoform has not been elucidated. Western biot analysis
revealed the expression of 18, 22 and 24-kD bFGF isoforms in cultured rat hippocampal astrocytes, and the expression of high
molecular weight (HMW)-isoforms (22 and 24-kD isoforms) but not of 18-kD isoform was selectively increased by cytokines. Immunofluorescent
analysis demonstrated that bFGF content in the cytoplasm of astrocytes is initially increased by cytokines followed by nuclear
targeting and localization in agreement with the previous evidence that HMW-isoforms possess a nuclear targeting signal. The
present results suggest the important role of HMW-bFGF isoforms in the response of nervous tissue to injury. 相似文献
2.
Demir AY Groothuis PG Dunselman GA Schurgers L Evers JL de Goeij AF 《Cell and tissue research》2005,322(2):299-311
We have studied menstrual effluent in order to identify soluble menstrual factors that induce epithelial to mesenchymal transitions
(EMT) in mesothelial cells. A variety of molecules, such as nitric oxide and its reaction products, proteases (i.e. matrix
metalloproteinases, plasmin) and proteins and/or peptides (i.e. growth factors: b-fibroblast growth factor, epidermal growth
factor, hepatocyte growth factor, transforming growth factor-β; cytokines: interleukin 1β, tumour necrosis factor-α [TNF-α])
may be involved in this process. We have demonstrated that TNF-α is involved in EMT, whereas the other molecules are not.
Biochemical analysis has shown that the inducing menstrual factors are heat-labile molecules, are uncharged at neutral pH,
have a molecular weight between 50–70 kDa (or are bound in complexes of that size) and are eluted in the albumin fraction
during gel filtration chromatography. Further analysis of this fraction by using proteomics and mass spectrometry has led
to the identification of α-enolase and haemoglobin whose inhibition partially prevents EMT. When antibodies against TNF-α,
α-enolase and haemoglobin are combined, EMT is almost completely inhibited. Thus, the candidates for soluble menstrual factors
that induce mesothelial EMT are TNF-α, α-enolase and haemoglobin. 相似文献
3.
Michael Hoffmann Mathias Schmidt Winfried Wels 《Cancer immunology, immunotherapy : CII》1998,47(3):167-175
Tumor necrosis factor (TNF)-α has a broad range of biological activities, which depend heavily on cell type and physiological
condition. In a panel of human tumor cell lines we analyzed expression of the receptor tyrosine kinases EGFR, ErbB2 and ErbB3,
and the response to TNF-α. Among the cell lines tested those resistant to TNF-α were found to express high levels of either
EGFR, or ErbB2 and ErbB3. In TNF-sensitive breast and cervical carcinoma cells activation of EGFR or ErbB2 by the exogenous
growth factors EGF and heregulin β1 resulted in a significant increase in the number of cells surviving TNF-α treatment. In
contrast, inhibition of EGFR activation in TNF-resistant breast carcinoma cells by the novel antagonistic anti-EGFR antibody
14E1 sensitized the cells to the cytotoxic effects of TNF-α. A bacterially expressed fusion protein consisting of a 14E1 single-chain
(sc) Fv antibody fragment linked to human TNF-α retained TNF-α activity. This scFv(14E1)-TNF-α molecule localized specifically
to EGFR on the surface of tumor cells and activated the NF-κB pathway in co-cultured T cells, as demonstrated by electrophoretic
mobility shift assays.
Received: 6 May 1998 / Accepted: 16 July 1998 相似文献
4.
The epidermal growth factor (EGF) family of polypeptides is regulators for tissue development and repair, and is characterized
by the fact that their mature forms are proteolytically derived from their integral membrane precursors. This article reviews
roles of the prominent members of the EGF family (EGF, transforming growth factor-alpha [TGF-α] and heparin-binding EGF [HB-EGF])
and the related neuregulin family in the nerve system. These polypeptides, produced by neurons and glial cells, play an important
role in the development of the nervous system, stimulating proliferation, migration, and differentiation of neuronal, glial,
and Schwann precursor cells. These peptides are also neurotrophic, enhancing survival and inhibiting apoptosis of post-mitotic
neurons, probably acting directly through receptors on neurons, or indirectly via stimulating glial proliferation and glial
synthesis of other molecules such as neurotrophic factors. TGF-α, EGF, and neuregulins are involved in mediating glial-neuronal
and axonal-glial interactions, regulating nerve injury responses, and participating in injury-associated astrocytic gliosis,
brain tumors, and other disorders of the nerve system. Although the collective roles of the EGF family (as well as those of
the neuregulins) are shown to be essential for the nervous system, redundancy may exist among members of the EGF family. 相似文献
5.
Kazuo Fushimi Kakuji Torigoe Hiroshi Yamauchi Shouji Furusako Masashi Kurimoto Masayoshi Namba 《In vitro cellular & developmental biology. Animal》1998,34(6):463-467
Summary To develop a new gene therapy model for cancer, a clonal cell line (KMST-6/TNF) which produces human tumor necrosis factor
α (hTNF-α) has been developed by introducing hTNF-α cDNA into a human immortal fibroblast cell line (KMST-6). The conditioned
medium (CM) of KMST-6/TNF cells inhibited the growth of various malignant human cell lines, but not that of normal human fibroblasts.
Although the growth inhibitory effects of KMST-6/TNF CM were neutralized to a considerable degree by anti-TNF-α antibody,
its inhibitory effects were more marked than the purified human natural TNF-α itself in the same units, suggesting that KMST-6/TNF
CM contains some growth inhibitory substances other than TNF-α. However, interferons α, β, and γ were undetectable in the
KMST-6/TNF CM. 相似文献
6.
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
7.
Birk Poller Jürgen Drewe Stephan Krähenbühl Jörg Huwyler Heike Gutmann 《Cellular and molecular neurobiology》2010,30(1):63-70
Brain capillary endothelial cells form the blood–brain barrier (BBB), a highly selective permeability membrane between the
blood and the brain. Besides tight junctions that prevent small hydrophilic compounds from passive diffusion into the brain
tissue, the endothelial cells express different families of drug efflux transport proteins that limit the amount of substances
penetrating the brain. Two prominent efflux transporters are the breast cancer resistance protein and P-glycoprotein (P-gp).
During inflammatory reactions, which can be associated with an altered BBB, pro-inflammatory cytokines are present in the
systemic circulation. We, therefore, investigated the effect of the pro-inflammatory cytokines interleukin-1β (IL-1β), interleukin-6
(IL-6) and tumor necrosis factor-α (TNF-α) on the expression and activity of BCRP and P-gp in the human hCMEC/D3 cell line.
BCRP mRNA levels were significantly reduced by IL-1β, IL-6 and TNF-α. The strongest BCRP suppression at the protein level
was observed after IL-1β treatment. IL-1β, IL-6 and TNF-α also significantly reduced the BCRP activity as assessed by mitoxantrone
uptake experiments. P-gp mRNA levels were slightly reduced by IL-6, but significantly increased after TNF-α treatment. TNF-α
also increased protein expression of P-gp but the uptake of the P-gp substrate rhodamine 123 was not affected by any of the
cytokines. This in vitro study indicates that expression levels and activity of BCRP, and P-gp at the BBB may be altered by
acute inflammation, possibly affecting the penetration of their substrates into the brain. 相似文献
8.
We have previously shown that oral administration of skimmed milk(SM) fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 (OLL1073R-1/SM) to DBA/1 mice inhibited the development of collagen-induced arthritis (CIA). In this study, our
aim was to examine possible mechanisms of inhibiting the development of CIA. We studied the effect of OLL1073R-1/SM on cytokine
secretion from cells of popliteal lymph nodes (lymph node cells; LNC) of mice. The results showed that feeding OLL1073R-1/SM
inhibited secretion of proinflammatory cytokines such as interferon γ (IFN-γ), interleukin 6 (IL-6), tumor necrosis factor
α (TNF-α) and the chemokine, monocyte chemoattractant protein 1 (MCP-1). The most prominent effect was inhibition of TNF-α.
Secretion of IL-2 and IL-4 were not influenced. Feeding OLL1073R-1/SM inhibited secretion of proinflammatory cytokines produced
by accessory cells, but not T cells. We conclude that CIA may be prevented via down regulation of secretion of proinflammatory
cytokines such as IL-6, TNF-α and IFN-γ, and of the chemokine of MCP-1.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
The failure of chondrocytes to replace the lost extracellular matrix contributes to the progression of degenerative disorders
of cartilage. Inflammatory mediators present in the joint regulate the breakdown of the established matrix and the synthesis
of new extracellular matrix molecules. In the present study, we investigated the effects of tumor necrosis factor alpha (TNF-α)
and epidermal growth factor (EGF) on chondrocyte morphology and matrix gene expression. Chondrocytes were isolated from distal
femoral condyles of neonatal rats. Cells in primary culture displayed a cobblestone appearance. EGF, but not TNF-α, increased
the number of cells exhibiting an elongated morphology. TNF-α potentiated the effect of EGF on chondrocyte morphology. Individually,
TNF-α and EGF diminished levels of aggrecan and type II collagen mRNA. In combination, the effects of TNF-α and EGF were additive,
indicating the involvement of discrete signaling pathways. Cell viability was not compromised by TNF-α or by EGF, alone or
in combination. EGF alone did not activate NF-κB or alter NF-κB activation by TNF-α. Pharmacologic studies indicated that
the effects of TNF-α and EGF alone or in combination were independent of protein kinase C signaling, but were dependent on
MEK1/2 activity. Finally, we analyzed the involvement of Sox-9 using a reporter construct of the 48 base pair minimal enhancer
of type II collagen. TNF-α attenuated enhancer activity as expected; in contrast, EGF did not alter either the effect of TNF-α
or basal activity. TNF-α and EGF, acting through distinct signaling pathways, thus have additive adverse effects on chondrocyte
function. These findings provide critical insights into the control of chondrocytes through the integration of multiple extracellular
signals. 相似文献
10.
Huang CD Ammit AJ Tliba O Kuo HP Penn RB Panettieri RA Amrani Y 《Journal of biomedical science》2005,12(5):763-776
Summary Using thapsigargin (Tg), an agent that mobilizes calcium by directly emptying intracellular stores, we previously showed that
intracellular calcium may play an important role in the regulation of intercellular adhesion molecule (ICAM)-1 gene expression
induced by cytokines in human airway smooth muscle (ASM) cells. In the present study, we extended this previous observation
by comparing the effect of Tg and other calcium-mobilizing G-protein-coupled receptor (GPCR) agonists on the expression of
different pro-inflammatory genes in response to tumor necrosis factor (TNF)-α in ASM cells. We found that in resting cells,
Tg (10–100 nM) or the bradykinin (BK) (1–10 μM) and thrombin (Thr) (1 U/ml) stimulated interleukin (IL)-6 secretion but had
no effect on regulated on activation, normal T cells expressed and secreted (RANTES) levels. More importantly, such calcium-mobilizing
agents significantly enhanced TNF-α-induced IL-6 secretion while RANTES secretion was abrogated. The use of luciferase-tagged
IL-6 and RANTES promoter constructs demonstrated similar effects of Tg on IL-6 and RANTES genes in basal and TNF-α-stimulated
conditions. The cyclic adenosine monophosphate (cAMP)-dependent pathway plays a minor role in this differential regulation
of IL-6 and RANTES genes expression. 2-Aminoethoxydiphenyl borate (APB), a blocker of store-operated calcium channels (SOCs),
and bisindolylmaleimide I (Bis I), a broad-spectrum protein kinase C (PKC) inhibitor, inhibited the basal and synergic effects
of IL-6 secretion in response to calcium-mobilizing agents and TNF-α, but did not prevent the abrogated effect of RANTES secretion.
We also found that Go-6976, a selective calcium-dependent PKC isozyme inhibitor, did not inhibit IL-6 secretion in response
to GPCR agonist and TNF-α; whereas Rottlerlin, a PKC-δ inhibitor, inhibited both Thr- and TNF-α-induced expression of IL-6,
while BK-induced IL-6 secretion was not affected. Interestingly, TNF-α-induced interferon regulatory factor (IRF)-1 activation
was significantly inhibited by all calcium-mobilizing agents, BK, Thr and Tg. These results show that calcium-mobilizing GPCR
agonists functionally interact with TNF-α to differentially regulate pro-inflammatory genes expression in human ASM cells,
possibly by involving Tg-sensitive intracellular calcium stores, SOC and PKC. 相似文献
11.
The role of the interaction between neurons and glial cells in the pathogenesis of neurodegenerative diseases is gaining more
attention. Neuroinflammation participates in the progressive nature of diverse neurologic diseases including Parkinson's disease,
Alzheimer's disease and multiple sclerosis. Activated microglia release neurotoxic molecules, which take part in the neuroinflammatory
responses. Astrocytes are also key players in these responses. Reactive astrocytes secrete inflammatory factors, including
tumor necrosis factor-α (TNF-α). This secretion can be regulated by extracellular ATP mediated through P2X7 receptors. However,
whether the activity of astrocytic P2X7 receptors changes in Parkinson’s disease and whether these changes would influence
the secretion of inflammatory factors in astrocytes are still unclear. In our study, through immunocytochemistry, whole-cell
patch clamp and ELISA assay, we found that P2X7 receptors were expressed in midbrain astrocytes, and that, rotenone, a Parkinson’s
disease model used at a low concentration (2–20 nM) for 48 h increased the P2X7 receptor current density and thereby inhibited
the secretion of TNF-α. Our research suggests that rotenone can regulate cytokine secretion of astrocytes through elevated
P2X7 channel current density and, in turn, take part in the neuroinflammatory process in the rotenone Parkinson’s disease
model. 相似文献
12.
Yao Z Qiu S Wang L Lu R Zhou CL Zhao PP Li HQ Gao WY 《Cancer immunology, immunotherapy : CII》2006,55(1):56-60
Tyroserleutide (YSL) is a type of active, low molecular weight polypeptide, comprised of three amino acids, which has antitumor
effects. YSL has various advantages over the other bioactive peptides such as its low molecular weight, simple construction,
nonimmunogenicity, specificity, few side effects, and ease of synthesis. However, the biological activities contributing to
it’s antitumor effects are not yet known. We studied the effects of YSL on the in vitro cytotoxic activity of BALB/c mice
peritoneal macrophages (PEMφ) against the target tumor cell lines BEL-7402 and B16-F10. We also measured the concentrations
of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and nitric oxide (NO) produced by YSL-activated Mφ, and we determined
the concentrations of IL-1β and NO secreted by YSL-activated murine macrophage RAW264.7 cells. YSL activated Mφ in vitro,
inhibited BEL-7402 proliferation, enhanced PEMφ antitumor effects, and stimulated IL-1β, TNF-α, and NO production by RAW264.7
cells. These data suggest that YSL activates the monocyte–macrophage system, which enhances Mφ antitumor effects against BEL-7402
and B16-F10 cells and stimulates the secretion by Mφ of cytotoxic effectors such as IL-1β, TNF-α, and NO. 相似文献
13.
To determine some early signs connected with the increased risk of future allergy development, gene expression and production
of selected cytokines were tested in children of allergic mothers and compared with newborns of healthy mothers. Expression
of IL-1β, IL-2, IL-4, IL-8, IL-10, IL-13, IFN-γ, TNF-α, TGF-β and EGF was tested in cord blood cells using real-time PCR and
production of these cytokines was evaluated in cord sera by ELISA. Gene expression of IL-2, IL-4, IL-8, IFN-γ, IL-1β, TNF-α
and TGF-β was decreased and that of IL-10, IL-13 and EGF increased in children of allergic mothers in comparison with those
of healthy mothers. Significant differences in sera of healthy and allergic groups were only in IL-10 and EGF. Different relationship
among serum cytokine levels reflects the fact that the cytokines are not produced only by blood cells. Significantly decreased
production of EGF in newborns of allergic mothers could negatively influence maturation of mucosal membranes of these children
and support thus their easier allergization. Allergic phenotype pointing to the bias to TH2 response and to possibly impaired intestine maturation was apparent already on the level of cord blood and could serve as
a predictive sign of increased allergy risk. 相似文献
14.
Balzer Sandrock Karen M. Hudson Douglas E. Williams Michael A. Lieberman 《In vitro cellular & developmental biology. Animal》1996,32(4):225-233
Summary The regulation of megakaryopoeisis by cytokines is not yet well understood. It is possible that autocrine loops are established
during megakaryocyte growth and differentiation, aiding in the maturation of these cells. The CHRF-288-11 human megakaryoblastic
cell line has been examined for cytokine production in growing cells and cells stimulated to differentiate by the addition
of phorbol esters. It has been demonstrated that these cells produce RNA corresponding to the interleukins IL-1α, 1β, 3, 7,
8, and 11, granulocyte-macrophage colony stimulating factor (GM-CSF), stem cell factor (SCF), transforming growth factor-β
(TGF-β), tumor necrosis factor-α (TNF-α), interferon-α (INF-α), and basic fibroblast growth factor (bFGF). Additionaly, RNA
corresponding to the receptors for IL-6, GM-CSF, SCF, INF-α,β, bFGF, and monocyte colony stimulating factor (M-CSF) were also
expressed by the cells. The receptor for TNF-α was detected immunologically. Analysis at the protein level demonstrated that
significant amounts of INF-α, TNF-α, GM-CSF, SCF, IL-1α, and a soluble form of the IL-6 receptor were produced by the cells.
Addition of phorbol esters to CHRF-288-11 cells enhances their megakaryocytic phenotype; such treatment also results in increased
secretion of INF-α, TNF-α, and GM-CSF. These results suggest that potential autocrine loops are established during the differentiation
of CHRF-288-11 cells, which may alter the capability of the cell to differentiate. These findings are similar to those recently
obtained for marrow-derived megakaryocytes (Jiang et al.) suggesting that CHRF-288-11 cells provide a useful model system
for the study of cytokine release during megakaryocyte differentiation. 相似文献
15.
de Souza LF Gelain DP Jardim FR Ribeiro GR Zim M Bernard EA 《Molecular and cellular biochemistry》2006,281(1-2):123-128
Recent reports have described purinergic modulation of tumor necrosis factor-alpha (TNF-α) signaling in neutrophils and astrocytes.
In Sertoli cells, both TNF-R1 and TNF-R2 TNF-α receptors are present and this cytokine modulates many functions of these cells
related to the maintenance of spermatogenesis. Sertoli cells express distinct purinoreceptors and previous work has shown
that these cells secrete extracellular nucleotides and their metabolites. In this work, we studied the possible role of extracellular
purines in TNF-α signaling in cultured Sertoli cells. This cytokine increased inosine concentration from 30 min to 6 h, with
no effect at 24 h. Both TNF-α and inosine increased nitrite accumulation and nitric oxide synthase activity. Erythro-9-(2-hydroxy-3-nonyl)adenine
(EHNA), an adenosine deaminase inhibitor, abolished the TNF-α induced inosine increase, nitrite accumulation and nitric oxide
synthase activity. These results suggest that extracellular inosine acts as intermediary in TNF-α stimulated nitric oxide
production in cultured Sertoli cells. 相似文献
16.
Peroxisome proliferator-activated receptor gamma (PPARγ) activation by its ligands reportedly inhibits monocyte function.
However, because the concentrations of PPARγ ligands used in previous studies were higher than typically expected to activate
PPARγ, we clarified whether PPARγ ligands influence monocyte function and cell viability of the human monocyte cell line THP-1.
We determined tumor necrosis factor-alpha (TNF-α) release as a monocyte function and cell viability using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium
bromide. Both troglitazone and 15-deoxy-Δ12,14-prostaglandin J2 (15-d-PGJ2) seemed to inhibit phorbol ester-induced TNF-α release from THP-1 cells. On the other hand, neither pioglitazone
nor rosiglitazone inhibited phorbol ester-induced TNF-α release. Because the cytotoxicity of troglitazone and 15-d-PGJ2 was
significantly (p<0.05, Tukey–Kramer) stronger than that of pioglitazone and rosiglitazone, the inhibition of TNF-α release seemed to parallel
the lack of cell viability. We concluded that PPARγ ligands did not directly inhibit TNF-α release in THP-1 cells.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
17.
Yeo Dae Yoon Eun Sook Lee Jong Pil Park Mee Ree Kim Jun Won Lee Tae Hoon Kim Min Kyun Na Jin Hee Kim 《Biotechnology and Bioprocess Engineering》2011,16(6):1099-1105
Hizikia fusiforme is a commonly used food that possesses potent anti-bacterial, anti-fungal, and anti-inflammatory activities. The immunostimulatory
activities of aqueous extract of Hizikia fusiforme (HFAE) in RAW 264.7 macrophages and whole spleen cells were investigated. HFAE activated RAW 264.7 macrophages to produce
cytokines such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in
a dose-dependent manner. In addition, HFAE induced the mRNA expression of TNF-α, IL-1β, and IL-6 in RAW 264.7 macrophages.
Moreover, HFAE stimulated proliferation of whole spleen cells and reference mitogen. Taken together, the results demonstrate
that HFAE potently activates the immune function by regulating NO, TNF-α, IL-1β, and IL-6 in RAW 264.7 macrophage and promoting
spleen cell proliferation. 相似文献
18.
19.
Summary Some intermediate filament (IF) proteins expressed in the development of glia include nestin, vimentin, and glial fibrillary acidic protein (GFAP). However, GFAP is the major intermediate filament protein of mature astrocytes. To determine the organization of GFAP in glial cells, rat GFAP cDNA tagged with enhanced green fluorescent protein (EGFP) was transfected into the rat C6 glioma cell line. After selection, two stable C6-EGFP-GFAP cell lines were established. Stable C6-EGFP-GFAP cell lines with or without heat shock treatment were analyzed by immunocytochemistry, electron microscopy, and Western blot analysis. In the transient transfection study, EGFP-GFAP transiently expressed in C6 cells formed punctate aggregations in the cytoplasm right after transfection, but gradually a filamentous structure of EGFP-GFAP was observed. The protein level of nestin in the C6-EGFP-GFAP stable clone was similar to that in the pEGFP-C1 transfected C6 stable clones and non-transfected C6 cells, whereas the level of vimentin was reduced in Western blotting. Interestingly, the expression level of small heat shock protein αB-crystallin in C6-EGFP-GFAP cells was also enhanced after transfection. Immunostaining patterns of C6-EGFP-GFAP cells showed that GFAP was dispersed as a fine filamentous structure. However, after heat shock treatment, GFAP formed IF bundles in C6-EGFP-GFAP cells. In the meantime, αB-crystallin also colocalized with IF bundles of GFAP in C6-EGFP-GFAP cells. The heat-induced GFAP reorganization we found suggested that small heat shock protein αB-crystallin may play a functional role regulating the cytoarchitecture of GFAP. 相似文献
20.
This study examined the interaction of the poorly metastatic human melanoma cell line M4Be and the highly metastatic clone
4 derived from M4Be, with respect to fresh adherent leukocytes (AL) isolated from 17 different healthy blood donors. These
AL contained 80% (73%–93%) monocytes, 15% (6%–20%) B lymphocytes and 5% (1%–8%) T lymphocytes. The survival of these tumor
cells against the stress exerted by these AL was estimated with a clonogenic assay where isolated tumor cells were co-cultured
for 14 days in contact with AL and lipopolysaccharide (LPS). For a given blood donor, AL either stimulates or inhibits the
colony formation of the tumor cells (T) depending on the AL/T ratio, the AL activation status and the metastatic potential
of tumor cells. At low AL/T ratios (<10/1) in the presence of low (8 ng/ml) and trace (8 pg/ml) levels of LPS, hydrogen peroxide
(H2O2) release is significantly reduced, and tumor cells significantly increase their colony formation; the feeder effect of AL
is suggested to be due to low concentrations of soluble tumor necrosis factor-alpha (TNF-α). At high AL/T ratios (>10/1),
whatever the characteristics of the blood donor, clone 4 is significantly more sensitive than M4Be to AL activated with medium
containing low (8 ng/ml) or high (1,000 ng/ml) levels of LPS; this killing effect is suggested to be due to TNF-α, both soluble
and membrane-bound, but not to be due to release of H2O2. These data suggest that the regulatory role of AL, which remove the majority of human melanoma cells and stimulate the colony
formation of a small fraction of them, is partly due to TNF-α.
Received: 2 November 2000 / Accepted: 15 February 2001 相似文献