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1.
There is now a wealth of information regarding the apoptotic mode of cell death and its importance in toxicological studies
in many mammalian organs including the liver. In this study, we investigated the modulatory effects of the heavy metal Zn2+ on transforming growth factor-β1 (TGF-β1)-induced apoptosis in primary rat hepatocytes. Apoptosis induced by TGF-β1 (1 ng/ml) in hepatocytes was accompanied by nuclear condensation as assessed morphologically by staining with Hoechst 33258
and DNA cleavage as detected biochemically by in situ end-labeling, field inversion and conventional gel electrophoresis. Pretreatment with 100 μmol/L Zn2+ abrogated the nuclear condensation, in situ end-labeling, and DNA laddering in TGF-β1-treated hepatocytes. Surprisingly, Zn2+ did not inhibit the formation of high-molecular-weight DNA fragments (30–50 kbp to 250–300 kbp). These data provide evidence
that Zn2+ exerts its effects on the endonucleases that act downstream in the execution phase of TGF-β1-induced apoptosis in hepatocytes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Dirk Pohlers Andreas Beyer Dirk Koczan Thomas Wilhelm Hans-Jürgen Thiesen Raimund W Kinne 《Arthritis research & therapy》2007,9(3):R59
Genome-wide gene expression was comparatively investigated in early-passage rheumatoid arthritis (RA) and osteoarthritis (OA)
synovial fibroblasts (SFBs; n = 6 each) using oligonucleotide microarrays; mRNA/protein data were validated by quantitative PCR (qPCR) and western blotting
and immunohistochemistry, respectively. Gene set enrichment analysis (GSEA) of the microarray data suggested constitutive
upregulation of components of the transforming growth factor (TGF)-β pathway in RA SFBs, with 2 hits in the top 30 regulated
pathways. The growth factor TGF-β1, its receptor TGFBR1, the TGF-β binding proteins LTBP1/2, the TGF-β-releasing thrombospondin
1 (THBS1), the negative effector SkiL, and the smad-associated molecule SARA were upregulated in RA SFBs compared to OA SFBs,
whereas TGF-β2 was downregulated. Upregulation of TGF-β1 and THBS1 mRNA (both positively correlated with clinical markers
of disease activity/severity) and downregulation of TGF-β2 mRNA in RA SFBs were confirmed by qPCR. TGFBR1 mRNA (only numerically
upregulated in RA SFBs) and SkiL mRNA were not differentially expressed. At the protein level, TGF-β1 showed a slightly higher
expression, and the signal-transducing TGFBR1 and the TGF-β-activating THBS1 a significantly higher expression in RA SFBs
than in OA SFBs. Consistent with the upregulated TGF-β pathway in RA SFBs, stimulation with TGF-β1 resulted in a significantly
enhanced expression of matrix-metalloproteinase (MMP)-11 mRNA and protein in RA SFBs, but not in OA SFBs. In conclusion, RA
SFBs show broad, constitutive alterations of the TGF-β pathway. The abundance of TGF-β, in conjunction with an augmented mRNA
and/or protein expression of TGF-β-releasing THBS1 and TGFBR1, suggests a pathogenetic role of TGF-β-induced effects on SFBs
in RA, for example, the augmentation of MMP-mediated matrix degradation/remodeling. 相似文献
3.
Effects of TGF-betas and a specific antagonist on apoptosis of immature rat male germ cells in vitro 总被引:1,自引:0,他引:1
Konrad L Keilani MM Laible L Nottelmann U Hofmann R 《Apoptosis : an international journal on programmed cell death》2006,11(5):739-748
Massive apoptosis of pubertal male germ cells is important for the development of functional spermatogenesis in the adult
testis. Although the trigger(s) for male germ cell loss at puberty remain undefined, we have hypothesized that transforming
growth factor-betas (TGF-βs) play an active role. Here we demonstrate that the three mammalian TGF-β isoforms, TGF-β1, TGF-β2
and TGF-β3, induce distinct apoptosis of pubertal spermatogonia and spermatocytes in a dose-dependent manner. Induction of
male germ cell death by activation of caspase-3 was most pronounced with TGF-β2 compared to TGF-β1 and TGF-β3. Furthermore,
we found colocalization of activated caspase-3 with apoptotic protease-activating factor-1 (Apaf-1) in apoptotic germ cells,
thus indicating the importance of the intrinsic mitochondrial pathway in TGF-β-induced apoptosis. The specificity of the TGF-β
effects was proven by addition of recombinant latency-associated peptide against TGF-β1 (rLAP-TGF-β1) which completely abolished
TGF-β1-induced and TGF-β3-induced germ cell apoptosis. Although TGF-β2-triggered germ cell death also was significantly reduced
by rLAP-TGF-β1, inhibition was not maximal. Our results suggest that the three TGF-β isoforms induce apoptosis of pubertal
male germ cells via the mitochondrial pathway in vitro and are thus likely candidates involved in the excessive first wave of apoptosis of male germ cells during puberty.
Lutz Konrad and Marcel Munir Keilani contributed equally to this work. 相似文献
4.
5.
Matsuzaki K 《Cell and tissue research》2012,347(1):225-243
Hepatocellular carcinoma (HCC) usually arises from hepatic fibrosis caused by chronic inflammation. In chronic liver damage,
hepatic stellate cells undergo progressive activation to myofibroblasts (MFB), which are important extracellular-matrix-producing
mesenchymal cells. Concomitantly, perturbation of transforming growth factor (TGF)-β signaling by pro-inflammatory cytokines
in the epithelial cells of the liver (hepatocytes) promotes both fibrogenesis and carcinogenesis (fibro-carcinogenesis). Insights
into fibro-carcinogenic effects on chronically damaged hepatocytes have come from recent detailed analyses of the TGF-β signaling
process. Smad proteins, which convey signals from TGF-β receptors to the nucleus, have intermediate linker regions between
conserved Mad homology (MH) 1 and MH2 domains. TGF-β type I receptor and pro-inflammatory cytokine-activated kinases differentially
phosphorylate Smad2 and Smad3 to create phosphoisoforms phosphorylated at the COOH-terminal, linker, or both (L/C) regions.
After acute liver injury, TGF-β-mediated pSmad3C signaling terminates hepatocytic proliferation induced by the pro-inflammatory
cytokine-mediated mitogenic pSmad3L pathway; TGF-β and pro-inflammatory cytokines synergistically enhance collagen synthesis
by activated hepatic stellate cells via pSmad2L/C and pSmad3L/C pathways. During chronic liver disease progression, pre-neoplastic
hepatocytes persistently affected by TGF-β together with pro-inflammatory cytokines come to exhibit the same carcinogenic
(mitogenic) pSmad3L and fibrogenic pSmad2L/C signaling as do MFB, thereby accelerating liver fibrosis while increasing risk
of HCC. This review of Smad phosphoisoform-mediated signals examines similarities and differences between epithelial and mesenchymal
cells in acute and chronic liver injuries and considers Smad linker phosphorylation as a potential target for the chemoprevention
of fibro-carcinogenesis. 相似文献
6.
Kelitha Maxis Aline Delalandre Johanne Martel-Pelletier Jean-Pierre Pelletier Nicolas Duval Daniel Lajeunesse 《Arthritis research & therapy》2007,8(6):R181
Osteoarthritis (OA) is characterized by articular cartilage degradation and hypertrophic bone changes with osteophyte formation
and abnormal bone remodeling. Two groups of OA patients were identified via the production of variable and opposite levels
of prostaglandin E2 (PGE2) or leukotriene B4 (LTB4) by subchondral osteoblasts, PGE2 levels discriminating between low and high subgroups. We studied whether the expression of 5-lipoxygenase (5-LO) or 5-LO-activating
protein (FLAP) is responsible for the shunt from prostaglandins to leukotrienes. FLAP mRNA levels varied in low and high OA
groups compared with normal, whereas mRNA levels of 5-LO were similar in all osteoblasts. Selective inhibition of cyclooxygenase-2
(COX-2) with NS-398-stimulated FLAP expression in the high OA osteoblasts subgroup, whereas it was without effect in the low
OA osteoblasts subgroup. The addition of PGE2 to the low OA osteoblasts subgroup decreased FLAP expression but failed to affect it in the high OA osteoblasts subgroup.
LTB4 levels in OA osteoblasts were stimulated about twofold by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) plus transforming growth factor-β (TGF-β), a situation corresponding to their effect on FLAP mRNA levels. Treatments with
1,25(OH)2D3 and TGF-β also modulated PGE2 production. TGF-β stimulated PGE2 production in both OA osteoblast groups, whereas 1,25(OH)2D3 alone had a limited effect but decreased the effect of TGF-β in the low OA osteoblasts subgroup. This modulation of PGE2 production was mirrored by the synthesis of COX-2. IL-18 levels were only slightly increased in a subgroup of OA osteoblasts
compared with normal; however, no relationship was observed overall between IL-18 and PGE2 levels in normal and OA osteoblasts. These results suggest that the shunt from the production of PGE2 to LTB4 is through regulation of the expression of FLAP, not 5-LO, in OA osteoblasts. The expression of FLAP in OA osteoblasts is
also modulated differently by 1,25(OH)2D3 and TGF-β depending on their endogenous low and high PGE2 levels. 相似文献
7.
Interleukin-1β enhances the effect of serum deprivation on rat annular cell apoptosis 总被引:3,自引:0,他引:3
Zhao CQ Liu D Li H Jiang LS Dai LY 《Apoptosis : an international journal on programmed cell death》2007,12(12):2155-2161
Excessive apoptosis of disc cells is believed to play an important role in intervertebral disc (IVD) degeneration. It has
been shown that interleukin-1β (IL-1β) is involved in the failure of disc matrix by suppressing the synthesis of matrix components
and stimulating the expression of matrix metalloproteinases. However, whether IL-1β induces disc cell apoptosis is still unclear.
The objective of this study was to investigate the effect of IL-1β on the apoptosis of rat annular cells cultured with or
without serum supplement. First-passage rat annular cells were cultured with 0% or 10% fetal bovine serum (FBS) supplement
and stimulated with 0, 10, 20 or 50 ng/ml IL-1β for 12, 24 or 48 h. Apoptotic incidences were quantified by flow cytometry,
morphologic changes in apoptotic cells were visualized by Hoechst 33258 staining and phase-contrast microscopy, and caspase-3
activity was also determined. When rat annular cells were cultured with 10% FBS supplement, no significant changes in apoptotic
incidences, apoptotic morphology and caspase-3 activity were observed even when cells were stimulated with 50 ng/ml IL-1β
for 48 h. In contrast, serum deprivation for 24 h led to an increase in apoptotic incidences, the number of apoptotic nuclei
and caspase-3 activity, and IL-1β significantly increased the effects of serum deprivation in a dose-dependent manner. Our
results indicate that IL-1β alone is not a sufficient stimulus to induce disc cell apoptosis and that in order to suppress
disc cell apoptosis, improving the nutrient supply to the disc may be more effective than antagonizing the adverse effects
of IL-1β. 相似文献
8.
9.
Dose-related influence of sodium selenite on apoptosis in human thyroid follicles in vitro induced by iodine, EGF, TGF-β, and H2O2 总被引:1,自引:0,他引:1
Lehmann P Rank P Hallfeldt KL Krebs B Gärtner R 《Biological trace element research》2006,112(2):119-130
Apoptosis of thyroid follicular cells is induced by high doses of iodide, epidermal growth factor (EGF), transforming growth
factor-β (TGF-β), as well as H2O2 and might be attenuated by antioxidants. Therefore, we examined the apoptotic index induced by these substances in selenium-treated
vs untreated human thyroid follicular cells. Reconstituted human thyroid follicles were incubated with sodium selenite (10
or 100 nM) for 72 h; controls received none. The follicles were then distributed to 24-well plates and incubated with potassium iodide
(5, 10, or 20 nM), EGF (5 ng/mL), TGF-β (5 ng/mL), or H2O2 (100 μM). Apoptosis was determined by a mitochondrial potential assay and the number of apoptotic cells counted by two independent,
experienced technicians and the glutathione peroxidase (GPx) activity was determined. A significant increase of apoptic cells
was obtained in control thyroid follicles treated with iodine (5, 10, or 20 μM), thyroid-stimulating hormone (TSH) 1, or 10 mU/mL in combination with 5 and 10 μM iodine, EGF (5 ng/mL) and TGF-β (5 ng/mL), or H2O2 (100 μM) (p<0.001). In contrast, in thyroid follicles preincubated with 10 or 100 nM sodium selenite, the apoptototic index was identical to the basal rate. In H2O2-treated follicles, the apoptotic index was still significantly elevated but 50% lower compared to control cells. The GPx
activity increased from 1.4±0.2 to 2.25±0.4 mU/μg DNA with 10 nM selenite and 2.6+0.4 mU/μg DNA with 100 nM selenite. Sodium selenite might increase the antioxidative potential in human thyroid follicles in vitro and therefore diminish
the apoptosis induced by TGF-β, EGF, iodide, and even H2O2 相似文献
10.
Jang TJ Kim NI Lee CH 《Apoptosis : an international journal on programmed cell death》2006,11(7):1131-1138
Non-steroidal anti-inflammatory drugs (NSAIDs) activated gene (NAG-1) is a newly identified member of the transforming growth
factor-β (TGF-β) superfamily. Members of the TGF-β family are multifunctional growth factors, and the nature of their effects
depends on the cellular context and cell type. NAG-1 has antitumorigenic and proapoptotic activities in colon and gastric
cancer cells lacking endogenous cyclooxgenase-2 (COX-2) expression. In contrast, COX-2 overexpression is related to antiapoptotic
activity. The purpose of this study is to evaluate the proapoptotic activity of NAG-1 according to COX-2 expression and cell
type. NAG-1 cDNA was transfected in SNU668 cells with endogenous COX-2 expression, SNU601 cells with forced COX-2 expression
and Hep3B hepatocellular carcinoma cells. SNU668 cells with ectopic expression of NAG-1 showed markedly elevated subG1 population,
induced death receptor-4 (DR-4) and DR-5, and revealed smaller active fragments of caspase-3. Forced COX-2 expression in SNU601
cells did not inhibit apoptosis caused by NAG-1 expression. Sulindac sulfide caused apoptosis, and induced expression of DR-5
and NAG-1 in Hep3B cells. However, Hep3B cells ectopically expressing NAG-1 did not cause apoptosis, and smaller active fragments
of caspase-3 and an 85 kDa band of poly ADP-ribose polymerase (PARP) did not appear in the transfected cells, either. This
study suggests that proapoptotic activity of NAG-1 is cell type specific and not related to COX-2 expression. 相似文献
11.
Oral squamous cell carcinoma (OSCC) is a world-wide health problem and its incidence accounts for 1.9–3.5% of all malignant
tumors. Transforming growth factor beta/Smads (TGF-β/Smads) signaling pathway plays an important role in oncogenesis, but
its function and molecular mechanisms in OSCC remain unclear. Expression of transforming growth factor-β receptor type II
(TβRII) and Smad4 was studied by immunohistochemistry in 108 OSCC patients and 10 normal controls. Function and molecular
mechanisms of TGF-β/Smads signaling pathway was then investigated in two human tongue squamous carcinoma cell lines with high
and low metastasis (Tb and Tca8113) by RT-PCR, Western Blot, immunofluorescence, cell growth curve and flow cytometry (FCM),
respectively. TβRII and Smad4 were significantly down-regulated in tumor tissues (with or without lymph node metastasis) compared
to normal oral epithelium tissues (P < 0.05). TGF-β1 induced arrest of the cell cycle rather than cell death in Tca8113 and Tb cells, and this influence was mediated
by the increasing the expression and changing the location of its downstream components of TGF-β1/Smads signaling pathway.
TGF-β1 rapidly increased the expression of p15 and p21 in both Tca8113 and Tb cells. TGF-β1 did not increase p27 expression
in Tca8113 cells, but p27 expression was increased in Tb cells. These indicated that TGF-β1 induced G1 arrest of cell cycle through a different regulating pathway in Tb cells compared with Tca8113 cells. Thus, we conclude that
TGF-β/Smads signaling pathway play a important role on cell growth and metastasis potential in OSCC.
Xiumei Wang, Wenjing Sun, and Jing Bai contributed equally to this paper. 相似文献
12.
Summary Platelet-derived growth factor (PDGF) and transforming growth factor beta-1(TGF-β1) were tested separately or together for
the ability to stimulate migration of human aortic vascular smooth muscle cells (VSMC). PDGF (10 ng/ml) stimulated migration
of VSMC over a 48-h period. TGF-β1 (10 ng/ml) had no effect on migration during the same period. VSMC exposed simultaneously
to both TGF-β1 and PDGF exhibited diminished migration (50%) when compared to cells treated only with PDGF. Cells that migrated
in the presence of PDGF possessed short actin cables that extended from cellular processes at the leading edge of migrating
cells; focal adhesions containing the αvβ3/β5 integrins localized to the same region. Cells grown in the presence of TGF-β1 exhibited long, intensely stained actin filaments
that spanned the entire length of the cell and were similar to untreated control VSMC. Focal adhesions containing αvβ3/β5 distributed evenly on the basal surface in both TGF-β1-treated cells and control cultures. Cellular responses to PDGF were
mitigated when TGF-β1 was present in the culture medium. VSMC grown in the presence of both PDGF and TGF-β1 exhibited elongated
actin filaments that were similar to nonmotile TGF-β1-treated cultures. Concomitant exposure of VSMC to PDGF and TGF-β1 resulted
in focal adhesions that distributed evenly on the lower cell surface. This study suggests that TGF-β1 can partially reverse
the stimulatory effect of PDGF on VSMC migration in vitro by modifying the actin cytoskeleton and the distribution of the α
vβ3/β5 integrins. 相似文献
13.
Huang EJ Wu CC Lee SD Chen JH Liu JY Ko JL Lin JA Lu MC Chen LM Huang CY Kuo WW 《Molecular and cellular biochemistry》2006,287(1-2):137-145
Hepatocellular carcinoma (HCC), the major manifestation of primary liver cancer, is one of the most frequent and malignant cancers worldwide, especially in Taiwan. Estrogen receptors (ERs) have been reported to play either a proliferation- or apoptosis-enhancing role in the differentiation of cancers, including HCC. In a previous experiment, we showed that transient overexpressed estrogen receptor-α induced early stage HCC cell line Hep 3B cell apoptosis by increasing the hTNF-α gene expression in a ligand-independent manner. To further clarify if the apoptotic effect occurs in poorly differentiated HCC cell line, HA22T, and elucidate the roles of ERs and TNF-α, DNA fragmentation and caspase activity were measured in late stage HCC cell line, HA22T, by measuring the expression of hER-α and hER-β using a Tetracycline-induciable system (Tet-on). Increased DNA fragmentation and caspase-3 activity were found in hERβ-overexpressed HA22T cells treated with estrogen (10−8 M) but not in hERα-overexpressed HA22T cells. Using RT-PCR/PCR and western blotting in HA22T cells, overexpressed hER-β was also found to increase the expression of hTNF-α mRNA and induce hTNF-α-dependent luciferase activity in a ligand-dependent manner. Additionally, LPS treatment and hER-β overexpression both enhance caspase-8 activities, whereas neither hER-β nor E2 treatment affected caspase-9 activities. In addition, the overexpressed hER-β plus E2 enhanced DNA fragmentation and caspase-8 activities were only partially reduced by anti-hTNF-α (0.1ng/ml), which was possibly due to the involvement of P53 and TGF-β. Taken together, our data indicates that overexpressed hER-β but not hER-α may induce caspase-8-mediated apoptosis by increasing the hTNF-α gene expression in a ligand-dependent manner in poorly differentiated HA22T cells. (Mol Cell Biochem xxx: 1–9, 2005)Shares equally contribution Contract grant sponsor: National Science Council; Contract grant number: NSC 91-2314-B-075A-006, NSC 92-2314-B-075A-014. 相似文献
14.
15.
Lasfer M Vadrot N Aoudjehane L Conti F Bringuier AF Feldmann G Reyl-Desmars F 《Cell biology and toxicology》2008,24(1):55-62
The heavy metal cadmium, an environmental pollutant, has been widely demonstrated to be toxic, in particular for liver. In
murines, cadmium induces apoptosis of hepatocytes and hepatomas. In human cells, apoptosis induced by cadmium has been exclusively
demonstrated in tumoral cell lines. Nothing was known in normal liver, in vitro or in vivo. In the present study, we examined the effects of cadmium in nonmalignant human hepatocytes. For that purpose, we investigated
whether cadmium was able to induce apoptosis of normal human hepatocytes (NHH) in primary culture and of a SV40-immortalized
human hepatocyte (IHH) cell line. Treatment of IHH and NHH with cadmium induced the presence of a sub-G1 population at 10 and 100 μmol/L, respectively. DAPI staining of both cell types treated with cadmium 100 μmol/L revealed
the induction of nuclear apoptotic bodies, supporting the hypothesis of apoptosis. In IHH and NHH, cadmium 100 μmol/L induced
PARP cleavage into a 85 kDa fragment. In order to investigate the involvement of mitochondria in cadmium-induced apoptosis,
we measured the mitochondrial membrane potential (ΔΨm). We observed that in IHH and NHH, cadmium 100 μmol/L induced a decrease of ΔΨm. As expected, cadmium under the same conditions enhanced caspase-9 and caspase-3 activities. In addition, cadmium from 1
to 100 μmol/L induced the expression of p53 and phosphorylation of its Ser15 in IHH and NHH. In conclusion, we showed in this
study that human hepatocytes were sensitive to cadmium and apoptosis induced at concentrations suggested in the literature
to inhibit p53 DNA-binding and DNA repair. 相似文献
16.
Liver fibrosis occurs in most types of chronic liver diseases and is characterized by excessive accumulation of extracellular
matrix proteins, leading to disruption of tissue function and eventually organ failure. Transforming growth factor (TGF)-β
represents an important pro-fibrogenic factor and aberrant TGF-β action has been implicated in many disease processes of the
liver. Endoglin is a TGF-β co-receptor expressed mainly in endothelial cells that has been shown to differentially regulates
TGF-β signal transduction by inhibiting ALK5-Smad2/3 signalling and augmenting ALK1-Smad1/5 signalling. Recent reports demonstrating
upregulation of endoglin expression in pro-fibrogenic cell types such as scleroderma fibroblasts and hepatic stellate cells
have led to studies exploring the potential involvement of this TGF-β co-receptor in organ fibrosis. A recent article by Meurer
and colleagues now shows that endoglin expression is increased in transdifferentiating hepatic stellate cells in vitro and
in two different models (carbon tetrachloride intoxication and bile duct ligation) of liver fibrosis in vivo. Moreover, they
show that endoglin overexpression in hepatic stellate cells is associated with enhanced TGF-β-driven Smad1/5 phosphorylation
and α-smooth muscle actin production without altering Smad2/3 signaling. These findings suggest that endoglin may play an
important role in hepatic fibrosis by altering the balance of TGF-β signaling via the ALK1-Smad1/5 and ALK-Smad2/3 pathways
and raise the possibility that targeting endoglin expression in transdifferentiating hepatic stellate cells may represent
a novel therapeutic strategy for the treatment of liver fibrosis. 相似文献
17.
Chien-Yuan Wang Ling-Lan Chen Pei-Yin Kuo Jia-Ling Chang Yng-Jiin Wang Shih-Chieh Hung 《Apoptosis : an international journal on programmed cell death》2010,15(4):439-449
Apoptosis is an inevitable process during development and is evident in the formation of articular cartilage and endochondral
ossification of growth plate. Mesenchymal stem cells (MSCs) can serve as alternative sources for cell therapy in focal chondral
lesions or diffuse osteoarthritis. But there are few, if any, studies investigating apoptosis during chondrogenesis by MSCs.
The aim of this study was to find the better condition to prevent apoptosis during chondrogenesis by MSCs. Apoptosis were
evaluated in MSCs induced in different chondrogenic media by the use of Annexin V, TUNEL staining, lysosomal labeling with
lysotracker and immunostaining of apoptotic markers. We found apparent apoptosis was demonstrated by Annexin V, TUNEL staining
and lysosomal labeling during chondrogenesis. Meanwhile, the degree of apoptosis was related to the reagents of the defined
chondrogenic medium. Adding serum in medium increased apoptosis, however, TGF-β1 inhibited apoptosis. The apoptosis was associated
with the activation of caspase-3, the increase in the Bax/Bcl-2 ratio, the loss of lysosomal integrity, and the increase of
PARP-cleavage. Pro-inflammatory cytokines, IL-1α, IL-1β and TNFα did not induce any increase in apoptosis. Interestingly,
the inhibition of apoptosis by serum free medium supplemented with ITS was also associated with an increase in the expression
of type II collagen, and a decrease in the expression of type X collagen, Runx2, and other osteogenic genes, while TGF-β1
increased the expression of Sox9, type II and type X collagen and decreased the expression of osteogenic genes. These data
suggest apoptosis occurs during chondrogenesis by MSCs by cell death intrinsic pathway activation and this process may be
modulated by culture conditions. 相似文献
18.
Activation of extracellular signal-regulated kinase by TGF-β1 via TβRII and Smad7 dependent mechanisms in human bronchial epithelial BEP2D cells 总被引:1,自引:0,他引:1
Huo YY Hu YC He XR Wang Y Song BQ Zhou PK Zhu MX Li G Wu DC 《Cell biology and toxicology》2007,23(2):113-128
Transforming growth factor-β1 (TGF-β1) can activate mitogen-activated protein kinases (MAPKs) in many types of cells. The
mechanism of this activation is not well elucidated. Here, we explore the role of TGF-β/Smads signaling compounds in TGF-β1-mediated
activation of extracellular signal-regulated kinase (ERK) MAPK in human papillomavirus (HPV)-18 immortalized human bronchial
epithelial cell line BEP2D and the role of TGF-β1-induced phosphorylation of ERK in proliferation and apoptosis of BEP2D.
The cell models of siRNA-mediated silencing of TGF-β receptor type II (TβRII), Smad2, Smad3, Smad4, and Smad7 were employed
in this study. Our results demonstrate that TGF-β1 activates ERK in a time-dependent manner with a maximum effect at 60 min;
overexpression of Smad7 increased this TGF-β1-mediated phosphorylation of the ERK; and siRNA-mediated silencing of TβRII,
Smad3, Smad4, and Smad7 abrogated this effect. Moreover, we observed that overexpression of Smad7 restored TGF-β1-mediated
ERK phosphorylation in Smad4 knockdown cells but not in TβRII knockdown cells. In BEP2D cells, TGF-β1 treatment effectively
inhibited cells’ proliferation and induced their apoptosis. Pretreatment with U0126, an inhibitor of ERK1/2, significantly
enhanced the TGF-β1-mediated antiproliferative and apoptosis induction effects in BEP2D cells. These data revealed that TβRII
and Smad7 play the critical roles in TGF-β1-mediated activation of ERK; Smad3 and Smad4 can play an indirect role through
up-regulating Smad7 expression; and TGF-β1-induced phosphorylation of ERK may participate in BEP2D cell proliferation and
apoptosis regulation. 相似文献
19.
Pleurocidin (GWGSFFKKAAHVGKHVGKAALTHYL-NH2), found in skin mucous secretions of the winter flounder Pleuronectes americanus, is known to possess a high potency and broad-spectrum antimicrobial peptide without cytotoxicity. In this study, to investigate the impact of pleurocidin on apoptotic progress, we observed morphological and physiological changes in Candida albicans. In cells exposed to pleurocidin, intracellular reactive oxygen species (ROS) which is a major cause of apoptosis were increased, and hydroxyl radicals were especially a large part of ROS. The increase of ROS induced oxidative stress and mitochondrial membrane depolarization which causes release of pro-apoptotic factors. Using FITC-VAD-FMK staining, we confirmed activation of yeast metacaspases which lead to apoptosis and phosphatidylserine externalization at early stage apoptosis was observed using annexin V FITC. In addition, pleurocidin induced-apoptotic cells underwent apoptotic morphological changes, showing the reduced cell size (low FSC) and enhanced intracellular density (high SSC) in flow cytometry dot plots. Under the influence of oxidative stress, DNA and nuclei were fragmented and condensed in cells, and they were visualized by 4′,6-diamidino-2-phenylindole (DAPI) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. These apoptotic phenomena represent that oxidative stress by inducing pleurocidin must be an important factor of the apoptotic process in C. albicans. 相似文献
20.
Méndez C Alcántara L Escalona R López-Casillas F Pedernera E 《Cell and tissue research》2006,325(1):143-149
The gonadal development of chicken embryo is regulated by hormones and growth factors. Transforming growth factor beta (TGF-β) isoforms may play a critical role in the regulation of growth in chicken gonads. We have investigated the effect of the TGF-β isoforms on the number of germ and somatic cells in the ovary of the chicken embryo. Ovaries were obtained from chicken embryos at 9 days of incubation. They were organ-cultured for 72 h in groups treated with TGF-β1, TGF-β2, soluble betaglycan, TGF-β1 plus soluble betaglycan, or TGF-β2 plus soluble betaglycan, and untreated (control). TGF-β1 and TGF-β2 diminished the somatic cell number in the ovary of the chicken embryo at this age by inhibiting the proliferation of the somatic cells without increasing apoptosis. On the other hand, TGF-β1 and TGF-β2 did not affect the number of germ cells in the cultured ovary. The capacity of TGF-β1 and TGF-β2 to diminish the number of somatic cells in the ovary was blocked with soluble betaglycan, a natural TGF-β antagonist. However, changes in the location of germ cells within the ovary suggested that TGF-β promoted the migration of the germ cells from the ovarian cortex to the medulla. Thus, TGF-β affects germ and somatic cells in the ovary of the 9-day-old chicken embryo and inhibits the proliferation of somatic cells.This work was supported by DGAPA-UNAM (IN214403) and CONACYT (45030). 相似文献