scholarly journals The Chaperone Function of hsp70 Is Required for Protection against Stress-Induced Apoptosis

2000 ◽  
Vol 20 (19) ◽  
pp. 7146-7159 ◽  
Author(s):  
Dick D. Mosser ◽  
Antoine W. Caron ◽  
Lucie Bourget ◽  
Anatoli B. Meriin ◽  
Michael Y. Sherman ◽  
...  
Keyword(s):  
Protective Effects ◽  
Atpase Domain ◽  
Caspase Activation ◽  
Apoptotic Pathway ◽  
Mutant Proteins ◽  
Chaperone Function ◽  
Induced Apoptosis ◽  
Jnk Activation ◽  
In Cells

ABSTRACT Cellular stress can trigger a process of self-destruction known as apoptosis. Cells can also respond to stress by adaptive changes that increase their ability to tolerate normally lethal conditions. Expression of the major heat-inducible protein hsp70 protects cells from heat-induced apoptosis. hsp70 has been reported to act in some situations upstream or downstream of caspase activation, and its protective effects have been said to be either dependent on or independent of its ability to inhibit JNK activation. Purified hsp70 has been shown to block procaspase processing in vitro but is unable to inhibit the activity of active caspase 3. Since some aspects of hsp70 function can occur in the absence of its chaperone activity, we examined whether hsp70 lacking its ATPase domain or the C-terminal EEVD sequence that is essential for peptide binding was required for the prevention of apoptosis. We generated stable cell lines with tetracycline-regulated expression of hsp70, hsc70, and chaperone-defective hsp70 mutants lacking the ATPase domain or the C-terminal EEVD sequence or containing AAAA in place of EEVD. Overexpression of hsp70 or hsc70 protected cells from heat shock-induced cell death by preventing the processing of procaspases 9 and 3. This required the chaperone function of hsp70 since hsp70 mutant proteins did not prevent procaspase processing or provide protection from apoptosis. JNK activation was inhibited by both hsp70 and hsc70 and by each of the hsp70 domain mutant proteins. The chaperoning activity of hsp70 is therefore not required for inhibition of JNK activation, and JNK inhibition was not sufficient for the prevention of apoptosis. Release of cytochrome c from mitochondria was inhibited in cells expressing full-length hsp70 but not in cells expressing the protein with ATPase deleted. Together with the recently identified ability of hsp70 to inhibit cytochromec-mediated procaspase 9 processing in vitro, these data demonstrate that hsp70 can affect the apoptotic pathway at the levels of both cytochrome c release and initiator caspase activation and that the chaperone function of hsp70 is required for these effects.

scholarly journals Role of the human heat shock protein hsp70 in protection against stress-induced apoptosis.

1997 ◽  
Vol 17 (9) ◽  
pp. 5317-5327 ◽  
Author(s):  
D D Mosser ◽  
A W Caron ◽  
L Bourget ◽  
C Denis-Larose ◽  
B Massie
Keyword(s):  
Cell Death ◽  
Heat Shock ◽  
Apoptotic Cell ◽  
Parp Cleavage ◽  
Substrate Protein ◽  
Resistance To Stress ◽  
Induced Apoptosis ◽  
Jnk Activation ◽  
In Cells

Resistance to stress-induced apoptosis was examined in cells in which the expression of hsp70 was either constitutively elevated or inducible by a tetracycline-regulated transactivator. Heat-induced apoptosis was blocked in hsp70-expressing cells, and this was associated with reduced cleavage of the common death substrate protein poly(ADP-ribose) polymerase (PARP). Heat-induced cell death was correlated with the activation of the stress-activated protein kinase SAPK/JNK (c-Jun N-terminal kinase). Activation of SAPK/JNK was strongly inhibited in cells in which hsp70 was induced to a high level, indicating that hsp70 is able to block apoptosis by inhibiting signaling events upstream of SAPK/JNK activation. In contrast, SAPK/JNK activation was not inhibited by heat shock in cells with constitutively elevated levels of hsp70. Cells that constitutively overexpress hsp70 resist apoptosis induced by ceramide, a lipid signaling molecule that is generated by apoptosis-inducing treatments and is linked to SAPK/JNK activation. Similar to heat stress, resistance to ceramide-induced apoptosis occurs in spite of strong SAPK/JNK activation. Therefore, hsp70 is also able to inhibit apoptosis at some point downstream of SAPK/JNK activation. Since PARP cleavage is prevented in both cell lines, these results suggest that hsp70 is able to prevent the effector steps of apoptotic cell death. Processing of the CED-3-related protease caspase-3 (CPP32/Yama/apopain) is inhibited in hsp70-expressing cells; however, the activity of the mature enzyme is not affected by hsp70 in vitro. Caspase processing may represent a critical heat-sensitive target leading to cell death that is inhibited by the chaperoning function of hsp70. The inhibition of SAPK/JNK signaling and apoptotic protease effector steps by hsp70 likely contributes to the resistance to stress-induced apoptosis seen in transiently induced thermotolerance.

Cyanidin-3-glucoside attenuates 4-hydroxynonenal- and visible light-induced retinal damage in vitro and in vivo

2019 ◽  
Vol 10 (5) ◽  
pp. 2871-2880 ◽  
Author(s):  
Yong Wang ◽  
Wentao Qi ◽  
Yazhen Huo ◽  
Ge Song ◽  
Hui Sun ◽  
...  
Keyword(s):  
Retinal Pigment Epithelial ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelial Cells ◽  
Retinal Damage ◽  
Protective Effects ◽  
Pigment Epithelial ◽  
Induced Apoptosis ◽  
Pigment Epithelial Cells

Cyanidin-3-glucoside has efficient protective effects on 4-hydroxynonenal-induced apoptosis, senescence, and angiogenesis in retinal pigment epithelial cells.

scholarly journals Isorhynchophylline Protects PC12 Cells Against Beta-Amyloid-Induced Apoptosis via PI3K/Akt Signaling Pathway

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yan-Fang Xian ◽  
Zhi-Xiu Lin ◽  
Qing-Qiu Mao ◽  
Jian-Nan Chen ◽  
Zi-Ren Su ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Pc12 Cells ◽  
Molecular Mechanisms ◽  
Glycogen Synthase ◽  
Neuroprotective Effect ◽  
Protective Action ◽  
Protective Effects ◽  
Phosphorylated Akt ◽  
Induced Apoptosis

The neurotoxicity of amyloid-β(Aβ) has been implicated as a critical cause of Alzheimer’s disease. Isorhynchophylline (IRN), an oxindole alkaloid isolated fromUncaria rhynchophylla,exerts neuroprotective effect againstAβ25–35-induced neurotoxicityin vitro. However, the exact mechanism for its neuroprotective effect is not well understood. The present study aimed to investigate the molecular mechanisms underlying the protective action of IRN againstAβ25–35-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. Pretreatment with IRN significantly increased the cell viability, inhibited the release of lactate dehydrogenase and the extent of DNA fragmentation inAβ25–35-treated cells. IRN treatment was able to enhance the protein levels of phosphorylated Akt (p-Akt) and glycogen synthase kinase-3β(p-GSK-3β). Lithium chloride blockedAβ25–35-induced cellular apoptosis in a similar manner as IRN, suggesting that GSK-3βinhibition was involved in neuroprotective action of IRN. Pretreatment with LY294002 completely abolished the protective effects of IRN. Furthermore, IRN reversedAβ25–35-induced attenuation in the level of phosphorylated cyclic AMP response element binding protein (p-CREB) and the effect of IRN could be blocked by the PI3K inhibitor. These experimental findings unambiguously suggested that the protective effect of IRN againstAβ25–35-induced apoptosis in PC12 cells was associated with the enhancement of p-CREB expression via PI3K/Akt/GSK-3βsignaling pathway.

scholarly journals Apigenin Suppresses Angiogenesis by Inhibiting Tube Formation and Inducing Apoptosis

2016 ◽  
Vol 11 (10) ◽  
pp. 1934578X1601101
Author(s):  
Hyun Ju Kim ◽  
Mok-Ryeon Ahn
Keyword(s):  
Umbilical Vein ◽  
Chorioallantoic Membrane ◽  
Tube Formation ◽  
Anticancer Activities ◽  
Apoptotic Pathway ◽  
Inhibition Of Angiogenesis ◽  
Induced Apoptosis ◽  
Umbilical Vein Endothelial Cells

Apigenin has been reported to exert angiogenic and anticancer activities in vitro. The mechanism of inhibition of angiogenesis by apigenin, however, has not been well-established. In this study, we investigated whether apigenin not only inhibited tube formation but also induced apoptosis in human umbilical vein endothelial cells (HUVECs). Furthermore, strong antiangiogenic activity of apigenin was observed in the in vivo assay using chick embryo chorioallantoic membrane (CAM). We also analyzed changes in survival signals and the apoptotic pathway through Western blotting. The results indicate that apigenin exerts its antiangiogenic effects through induction of endothelial apoptosis.

Azacytidine Suppressors Autocrine IL-6 Secretion and Demonstrates In Vitro and In Vivo Activity Against Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1566-1566
Author(s):  
Tiffany Khong ◽  
Janelle Sharkey ◽  
Andrew Spencer
Keyword(s):  
Multiple Myeloma ◽  
Murine Model ◽  
Dna Methyltransferase ◽  
Myeloma Cell ◽  
Apoptotic Pathway ◽  
P16 Gene ◽  
Induced Apoptosis ◽  
The Impact

Abstract Azacytidine (AZA), a DNA methyltransferase inhibitor, has been shown to inhibit cell growth and induce apoptosis in some cancer cells. We determined the impact of AZA on a panel of human myeloma cell lines (HMCL); KMS 12PE, KMS 18, LP-1, NCI-H929, OPM-2, RPMI-8226 and U266 and in an in vivo murine model of multiple myeloma (5T33 model). Dose responsiveness to AZA was determined via MTS assays with a range of AZA doses (1–10mM) for 72 hours. FACS and cell cycle analysis were used to evaluate the profile of the cells after exposure to AZA for 72 hours. MTS assays demonstrated a dose and time dependent AZA-induced inhibition of HMCL viability with effective concentrations of AZA ranging from 1–10 mM. This was associated with accumulation of cells in the Go/G1 phase with decreasing number of cells in the S and G2/M phases. Western Blot analysis using antibodies against caspases 3,8,10, PARP, phospho-ERK, ERK, Stat3 and phospho -Stat3 were performed to help characterize the mechanism(s) of cell killing. Cleavage of caspases 3,8,10 and PARP within 24 hours of AZA treatment confirmed early AZA-induced HMCL apoptosis. phospho-ERK which was absent in untreated U266 appeared after 48 hours exposure to 5mM AZA. Similarly inhibitors of caspases 3,8 and 9 were used to determine which apoptotic pathway was being preferentially activated by AZA. Inhibitors of both caspase 3 and 9 effectively abrogated AZA-induced apoptosis in U266 and NCI-H929. In contrast caspase 8 inhibitor was less effective which is consistent with AZA acting via the mitochondrial apoptotic pathway. Reactivation of p16 gene by AZA-induced hypomethylation was assessed with methylation specific PCR. MSP-PCR of the p16 gene indicated a loss of methylation and up-regulated transcription after 48 hours treatment with 5 mM AZA. The level of IL-6 in conditioned media from U266 cells treated with AZA was determined by ELISA assay and demonstrated a rapid fall in autocrine IL-6 production. RT-PCR demonstrated rapid AZA-induced cessation of IL-6 transcription temporarily associated with the disappearance of upstream phospho -Stat3. Addition of exogenous IL-6 did not rescue U266 from AZA-induced apoptosis. AZA was also administered to a 5T33 murine model of multiple myeloma at increasing concentrations (1, 3, 10 mg/kg). At 10 mg/kg the median survival of vehicle versus AZA treated mice was 28 days versus 30+ days (p=0.003). These findings justify further evaluation of AZA as a potential therapeutic agent for multiple myeloma.

scholarly journals Regions of the Herpes Simplex Virus Type 1 Latency-Associated Transcript That Protect Cells from Apoptosis In Vitro and Protect Neuronal Cells In Vivo

2002 ◽  
Vol 76 (2) ◽  
pp. 717-729 ◽  
Author(s):  
Maryam Ahmed ◽  
Martin Lock ◽  
Cathie G. Miller ◽  
Nigel W. Fraser
Keyword(s):  
Herpes Simplex ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Exon 1 ◽  
Induced Apoptosis ◽  
Simplex Virus ◽  
In Cells

ABSTRACT Recent studies have suggested that the latency-associated transcript (LAT) region of herpes simplex virus type 1 (HSV-1) is effective at blocking virus-induced apoptosis both in vitro and in the trigeminal ganglia of acutely infected rabbits (Inman et al., J. Virol. 75:3636–3646, 2001; Perng et al., Science 287:1500–1503, 2000). By transfecting cells with a construct expressing the Pst-Mlu segment of the LAT, encompassing the LAT exon 1, the stable 2.0-kb intron, and 5′ part of exon 2, we confirmed that this region was able to diminish the onset of programmed cell death initiated by anti-Fas and camptothecin treatment. In addition, caspase 8-induced apoptosis was specifically inhibited in cells expressing the Pst-Mlu LAT fragment. To further delineate the minimal region of LAT that is necessary for this antiapoptotic function, LAT mutants were used in our cotransfection assays. In HeLa cells, the plasmids lacking exon sequences were the least effective at blocking apoptosis. However, similar to previous work (Inman et al., op. cit.), our data also indicated that the 5′ end of the stable 2.0-kb LAT intron appeared to contribute to the promotion of cell survival. Furthermore, cells productively infected with the 17N/H LAT mutant virus, a virus deleted in the LAT promoter, exon 1, and about half of the intron, exhibited a greater degree of DNA fragmentation than cells infected with wild-type HSV-1. These data support the finding that the exon 1 and 2.0-kb intron region of the LAT transcription unit display an antiapoptotic function both in transfected cells and in the context of the virus infection in vitro. In trigeminal ganglia of mice acutely infected with the wild-type virus, 17, and 17ΔSty, a virus lacking most of exon 1, apoptosis was not detected in cells that were positive for virus particles. However, dual staining was observed in cells from mice infected with 17N/H virus, indicating that the LAT antiapoptotic function demonstrated in cells transfected by LAT-expressing constructs may also play a role in protecting cells from virus-induced apoptosis during acute viral infection in vivo.

scholarly journals Dexmedetomidine protects against oxygen-glucose deprivation/reoxygenation injury-induced apoptosis via the p38 MAPK/ERK signalling pathway

2017 ◽  
Vol 46 (2) ◽  
pp. 675-686 ◽  
Author(s):  
Ke Wang ◽  
Yuekun Zhu
Keyword(s):  
Cell Survival ◽  
P38 Mapk ◽  
Glucose Deprivation ◽  
Signalling Pathway ◽  
Cell Counting ◽  
Oxygen Glucose Deprivation ◽  
Protective Effects ◽  
N2a Cells ◽  
Induced Apoptosis

Objective To investigate the protective effects of dexmedetomidine (DEX) in oxygen-glucose deprivation/reoxygenation (OGD/R) injury, which is involved in a number of ischaemic diseases. Methods An in vitro OGD/R injury model was generated using mouse Neuro 2A neuroblastoma (N2A) cells. Different concentrations of DEX were administrated to OGD/R cells. CV-65 was used to inhibit p38 microtubule associated protein kinase/extracellular signal-regulated kinases (MAPK/ERK) signalling. Cell proliferation, cell cycle, apoptosis, and the levels of proteins related to p38 MAPK/ERK signalling and apoptosis were evaluated using Cell Counting Kit-8, flow cytometry, TdT-UTP nick end labelling and Western blot analysis, respectively. Results DEX treatment of OGD/R cells promoted cell survival and attenuated OGD/R-induced cell apoptosis. It also activated the p38 MAPK/ERK signalling pathway, increased the levels of Bcl-2, and decreased the levels of Bax and cleaved caspase-3. Treatment with the p38 MAPK/ERK inhibitor CV-65 inhibited the activation of p38 MAPK/ERK and abrogated the DEX-induced effects on cell survival and apoptosis. Conclusions DEX protects N2A cells from OGD/R-induced apoptosis via the activation of the p38 MAPK/ERK signalling pathway. DEX might be an effective agent for the treatment of ischaemic diseases.

scholarly journals Evidence for a Novel, Caspase-8-Independent, Fas Death Domain-Mediated Apoptotic Pathway

2004 ◽  
Vol 2004 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Hanping Feng ◽  
Yi Zeng ◽  
Michael W. Graner ◽  
Luke Whitesell ◽  
Emmanuel Katsanis
Keyword(s):  
Transmembrane Potential ◽  
Caspase 8 ◽  
Death Domain ◽  
Caspase Inhibitor ◽  
Caspase Activation ◽  
Null Cell ◽  
Apoptotic Pathway ◽  
Induced Apoptosis ◽  
Mitochondrial Transition Pore ◽  
Pore Permeability

Certain caspase-8 null cell lines demonstrate resistance to Fas-induced apoptosis, indicating that the Fas/FasL apoptotic pathway may be caspase-8-dependent. Some reports, however, have shown that Fas induces cell death independent of caspase-8. Here we provide evidence for an alternative, caspase-8-independent, Fas death domain-mediated apoptotic pathway. Murine 12B1-D1 cells express procaspase-3, -8, and -9, which were activated upon the dimerization of Fas death domain. Bid was cleaved and mitochondrial transmembrane potential was disrupted in this apoptotic process. All apoptotic events were completely blocked by the broad-spectrum caspase inhibitor Z-VAD-FMK, but not by other peptide caspase inhibitors. Cyclosporin A (CsA), which inhibits mitochondrial transition pore permeability, blocked neither pore permeability disruption nor caspase activation. However, CsA plus caspase-8 inhibitor blocked all apoptotic events of 12B1-D1 induced by Fas death domain dimerization. Our data therefore suggest that there is a novel, caspase-8-independent, Z-VAD-FMK-inhibitable, apoptotic pathway in 12B1-D1 cells that targets mitochondria directly.

scholarly journals Time Dependent Appearance of Selected Apoptotic Markers and Usefulness of Their Detection In vitro

2002 ◽  
Vol 45 (4) ◽  
pp. 135-144 ◽  
Author(s):  
Emil Rudolf ◽  
Miroslav Červinka
Keyword(s):  
Caspase 3 ◽  
Potassium Chromate ◽  
Experimental Setting ◽  
Apoptotic Pathway ◽  
Detection Systems ◽  
Chemically Induced ◽  
Cell Blebbing ◽  
Temporary Decrease ◽  
Induced Apoptosis

Many experiments have demonstrated that some cell lines are resistant to chemically induced apoptosis in vitro, and that apoptosis itself is far from being a homogenous phenomenon. Here we show that 10 μg/ml etoposide elicited only minor changes in Bowes human melanoma cells (temporary decrease in cell viability and proliferation, transient phospatidylserine externalization and caspase-3 activation), which weren’t clearly capable to start apoptotic pathway in the entire treated population. On the other hand, potassium chromate at concentration of 150 μg/ml executed cell death bearing some features of apoptosis (cell blebbing, caspase-3 activation and cytoskeletal changes) but lacking or showing weakly others (DNA fragmentation and phospatidylserine externalization). Our results suggest that in detecting apoptosis several faultproof detection systems are to be used to avoid misleading results and conclusions in each experimental setting.

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