Rapamycin Affects Palmitate-Induced Lipotoxicity in Osteoblasts by Modulating Apoptosis and Autophagy

2019 ◽  
Vol 75 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Ahmed Al Saedi ◽  
Craig A. Goodman ◽  
Damian E. Myers ◽  
Alan Hayes ◽  
Gustavo Duque
Keyword(s):  
Time Course ◽  
Marrow Fat ◽  
Human Osteoblasts ◽  
Protein Levels ◽  
Mtorc1 Pathway ◽  
The Media ◽  
Normal Human ◽  
Induced Apoptosis ◽  
Confocal Fluorescence Imaging

Abstract Bone marrow fat infiltration is one of the hallmarks of aging and osteoporotic bones. Marrow adipocytes produce substantial amounts of palmitic acid (PA). PA is toxic to bone-forming osteoblasts in vitro, affecting their differentiation, function, and survival. Since rapamycin (RAP)-induced inhibition of target of rapamycin complex 1 (mTORC1) activates autophagy and prevents apoptosis, we hypothesized that RAP may preserve osteoblast viability and reduce PA-induced lipotoxicity. Normal human osteoblasts were incubated with RAP in the presence of a lipotoxic concentration of PA or vehicle for 24 and 48 hours. Expression of LC3 protein levels and the phosphorylation of the direct mTORC1 target p70S6K1-T389 were quantified by Western blot. Lysosomes and autophagosomes were studied using confocal fluorescence imaging, lysotracker, and live-cell imaging. RAP reduced PA-induced apoptosis. In addition, PA-induced autophagosome formation increased substantially over the time-course, an effect that was significantly regulated by the presence of RAP in the media. In addition, LC3I/II ratios were higher in PA-induced cells with RAP whereas p70S6K1-T389 were lower in PA and RAP together. In summary, this study highlights the role of the RAP-sensitive mTORC1 pathway in normal human osteoblasts under lipotoxic conditions. RAP-associated therapies could, potentially, be targeted for specific roles in osteoporosis and aging bone.

scholarly journals Wnt/β-Catenin and Wnt5a/Ca2+ Pathways Regulate Proliferation and Apoptosis of Keratinocytes in Psoriasis Lesions

2015 ◽  
Vol 36 (5) ◽  
pp. 1890-1902 ◽  
Author(s):  
Yanfei Zhang ◽  
Chen Tu ◽  
Dingwei Zhang ◽  
Yan Zheng ◽  
Zhenhui Peng ◽  
...  
Keyword(s):  
Human Keratinocytes ◽  
Mrna Levels ◽  
Protein Levels ◽  
Proliferation And Apoptosis ◽  
Genes Encoding ◽  
Keratinocyte Cell ◽  
Normal Human ◽  
Induced Apoptosis ◽  
Psoriatic Lesions

Background/Aims: Wnt5a is overexpressed in psoriasis lesions, however the mechanism by which Wnt5a is involved in the pathogenesis of psoriasis is not clear. To address this, the expression of Wnt5a in psoriatic lesions and its effect on keratinocyte cell proliferation and apoptosis was examined in vitro. Methods: The expression levels of WNT5A, and genes encoding its receptors frizzled2 (FZD2) and frizzled5 (FZD5) were examined in samples obtained from individuals with psoriasis and healthy controls. Knockdown of Wnt5a with short interfering (si)RNAs was performed in cultured HaCaT keratinocytes and normal human keratinocytes (NHK), and the expression of Wnt5a, protein kinase C (PKC), and β-catenin were determined, and cell cycle activity, proliferation and apoptosis were assessed. Results: The expression of WNT5A, FZD2 and FZD5 mRNA and protein were increased in psoriatic lesions. Wnt5a knockdown suppressed proliferation and induced apoptosis in HaCaT and NHK cells. Additionally, expression of PCNA, MKI67, CCND1, BCL2, CTNNB1, and genes encoding PKC and survivin were downregulated, whereas CASP3 was upregulated. The mRNA levels of the Wnt pathway inhibitors DKK1 and SFRP1 were upregulated, Western blotting analyses demonstrated reduction in β-catenin and PKC protein levels. Conclusion: Knockdown of Wnt5a suppresses the proliferation of keratinocytes and induces apoptosis by inhibiting the Wnt/β-catenin or Wnt5a/Ca2+ pathways.

Bortezomib blocks Bax degradation in malignant B cells during treatment with TRAIL

Blood ◽  
2008 ◽  
Vol 111 (5) ◽  
pp. 2797-2805 ◽  
Author(s):  
Feng-Ting Liu ◽  
Samir G. Agrawal ◽  
John G. Gribben ◽  
Hongtao Ye ◽  
Ming-Qing Du ◽  
...  
Keyword(s):  
B Cells ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Resistant Cell ◽  
Protein Levels ◽  
Bax Protein ◽  
Degradation Activity ◽  
Potent Drug ◽  
Induced Apoptosis

Proapoptotic Bcl-2 family member Bax is a crucial protein in the induction of apoptosis, and its activation is required for this process. Here we report that Bax is a short-lived protein in malignant B cells and Bax protein levels decreased rapidly when protein synthesis was blocked. Malignant B cells were relatively resistant to tumor necrosis factor–related apoptosis inducing ligand (TRAIL)–induced apoptosis, and this correlated with low basal Bax protein levels. Furthermore, during treatment with TRAIL, the resistant cell lines showed prominent Bax degradation activity. This degradation activity was localized to mitochondrial Bax and could be prevented by truncated Bid, a BH3-only protein; in contrast, cytosolic Bax was relatively stable. The proteasome inhibitor bortezomib is a potent drug in inducing apoptosis in vitro in malignant B-cell lines and primary chronic lymphocytic leukemic (CLL) cells. In CLL cells, bortezomib induced Bax accumulation, translocation to mitochondria, conformational change, and oligomerization. Accumulation and stabilization of Bax protein by bortezomib-sensitized malignant B cells to TRAIL-induced apoptosis. This study reveals that Bax instability confers resistance to TRAIL, which can be reversed by Bax stabilization with a proteasome inhibitor.

scholarly journals Complexing of the CD-3 subunit by a monoclonal antibody activates a microtubule-associated protein 2 (MAP-2) serine kinase in Jurkat cells

1989 ◽  
Vol 262 (2) ◽  
pp. 449-456 ◽  
Author(s):  
C Hanekom ◽  
A Nel ◽  
C Gittinger ◽  
A Rheeder ◽  
G Landreth
Keyword(s):  
T Cells ◽  
Time Course ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Jurkat Cells ◽  
Serine Kinase ◽  
Transient Activation ◽  
Normal Human ◽  
Dose Dependent

Treatment of Jurkat T-cells with anti-CD-3 monoclonal antibodies resulted in the rapid and transient activation of a serine kinase which utilized the microtubule-associated protein, MAP-2, as a substrate in vitro. The kinase was also activated on treatment of Jurkat cells with phytohaemagglutinin, but with a different time course. The activation of the MAP-2 kinase by anti-CD-3 antibodies was dose-dependent, with maximal activity observed at concentrations of greater than 500 ng/ml. Normal human E-rosette-positive T-cells also exhibited induction of MAP-2 kinase activity during anti-CD-3 treatment. The enzyme was optimally active in the presence of 2 mM-Mn2+; lower levels of activity were observed with Mg2+, even at concentrations up to 20 mM. The kinase was partially purified by passage over DE-52 Sephacel with the activity eluting as a single peak at 0.25 M-NaCl. The molecular mass was estimated to be 45 kDa by gel filtration. The activation of the MAP-2 kinase was probably due to phosphorylation of this enzyme as treatment with alkaline phosphatase diminished its activity. These data demonstrate that the stimulation of T-cells through the CD-3 complex results in the activation of a novel serine kinase which may be critically involved in signal transduction in these cells.

Casticin Induced Apoptosis in A375.S2 Human Melanoma Cells through the Inhibition of NF-κB and Mitochondria-Dependent Pathways In Vitro and Inhibited Human Melanoma Xenografts in a Mouse Model In Vivo

2016 ◽  
Vol 44 (03) ◽  
pp. 637-661 ◽  
Author(s):  
Yin-Wen Shiue ◽  
Chi-Cheng Lu ◽  
Yu-Ping Hsiao ◽  
Ching-Lung Liao ◽  
Jing-Pin Lin ◽  
...  
Keyword(s):  
Human Melanoma ◽  
Oxygen Species ◽  
Protein Levels ◽  
Phase Arrest ◽  
Viable Cells ◽  
M Phase ◽  
Induced Apoptosis ◽  
Western Blotting Assay

Casticin, a polymethoxyflavone occurring in natural plants, has been shown to have anticancer activities. In the present study, we aims to investigate the anti-skin cancer activity of casticin on melanoma cells in vitro and the antitumor effect of casticin on human melanoma xenografts in nu/nu mice in vivo. A flow cytometric assay was performed to detect expression of viable cells, cell cycles, reactive oxygen species production, levels of [Formula: see text] and caspase activity. A Western blotting assay and confocal laser microscope examination were performed to detect expression of protein levels. In the in vitro studies, we found that casticin induced morphological cell changes and DNA condensation and damage, decreased the total viable cells, and induced G2/M phase arrest. Casticin promoted reactive oxygen species (ROS) production, decreased the level of [Formula: see text], and promoted caspase-3 activities in A375.S2 cells. The induced G2/M phase arrest indicated by the Western blotting assay showed that casticin promoted the expression of p53, p21 and CHK-1 proteins and inhibited the protein levels of Cdc25c, CDK-1, Cyclin A and B. The casticin-induced apoptosis indicated that casticin promoted pro-apoptotic proteins but inhibited anti-apoptotic proteins. These findings also were confirmed by the fact that casticin promoted the release of AIF and Endo G from mitochondria to cytosol. An electrophoretic mobility shift assay (EMSA) assay showed that casticin inhibited the NF-[Formula: see text]B binding DNA and that these effects were time-dependent. In the in vivo studies, results from immuno-deficient nu/nu mice bearing the A375.S2 tumor xenograft indicated that casticin significantly suppressed tumor growth based on tumor size and weight decreases. Early G2/M arrest and mitochondria-dependent signaling contributed to the apoptotic A375.S2 cell demise induced by casticin. In in vivo experiments, A375.S2 also efficaciously suppressed tumor volume in a xenotransplantation model. Therefore, casticin might be a potential therapeutic agent for the treatment of skin cancer in the future.

Arsenic induces apoptosis of multidrug-resistant human myeloid leukemia cells that express Bcr-Abl or overexpress MDR, MRP, Bcl-2, or Bcl-xL

Blood ◽  
2000 ◽  
Vol 95 (3) ◽  
pp. 1014-1022 ◽  
Author(s):  
Charles Perkins ◽  
Caryn N. Kim ◽  
Guofu Fang ◽  
Kapil N. Bhalla
Keyword(s):  
Myeloid Leukemia ◽  
Blast Crisis ◽  
K562 Cells ◽  
Cell Types ◽  
Multidrug Resistant ◽  
Leukemia Cells ◽  
Protein Levels ◽  
Growth Inhibitory ◽  
Induced Apoptosis

We investigated the in vitro growth inhibitory and apoptotic effects of clinically achievable concentrations of As2O3 (0.5 to 2.0 μmol/L) against human myeloid leukemia cells known to be resistant to a number of apoptotic stimuli. These included chronic myelocytic leukemia (CML) blast crisis K562 and HL-60/Bcr-Abl cells, which contain p210 and p185 Bcr-Abl, respectively, and HL-60 cell types that overexpress Bcl-2 (HL-60/Bcl-2), Bcl-xL(HL-60/Bcl-xL), MDR (HL-60/VCR), or MRP (HL-60/AR) protein. The growth-inhibitory IC50 values for As2O3 treatment for 7 days against all these cell types ranged from 0.8 to 1.5 μmol/L. Exposure to 2 μmol/L As2O3 for 7 days induced apoptosis of all cell types, including HL-60/Bcr-Abl and K562 cells. This was associated with the cytosolic accumulation of cyt c and preapoptotic mitochondrial events, such as the loss of inner membrane potential (▵Ψm) and the increase in reactive oxygen species (ROS). Treatment with As2O3 (2 μmol/L) generated the activities of caspases, which produced the cleavage of the BH3 domain containing proapoptotic Bid protein and poly (ADP-ribose) polymerase. Significantly, As2O3-induced apoptosis of HL-60/Bcr-Abl and K562 cells was associated with a decline in Bcr-Abl protein levels, without any significant alterations in the levels of Bcl-xL, Bax, Apaf-1, Fas, and FasL. Although As2O3 treatment caused a marked increase in the expression of the myeloid differentiation marker CD11b, it did not affect Hb levels in HL-60/Bcr-Abl, K562, or HL-60/neo cells. However, in these cells, As2O3 potently induced hyper-acetylation of the histones H3 and H4. These findings characterize As2O3 as a growth inhibiting and apoptosis-inducing agent against a variety of myeloid leukemia cells resistant to multiple apoptotic stimuli.

The Regulation of Natural Food Dyes Curcumin on the Amyloidogenic Pathway of APP

2013 ◽  
Vol 781-784 ◽  
pp. 1160-1163
Author(s):  
Xiong Zhang ◽  
Jie Yun Sun ◽  
Hong Mei Zhang ◽  
Lu Si ◽  
Yu Li
Keyword(s):  
Time Course ◽  
Mrna Level ◽  
Time Dependent ◽  
Hek293 Cells ◽  
Natural Food ◽  
Inhibition Effect ◽  
Dose Time ◽  
Protein Levels ◽  
Food Dyes

As a promising prevention and therapeutic intervention in Alzheimer’s disease, natural food dyes curcumin could obviously inhibit the generation of Aβ, but the mechanism is not fully defined. This study aims to investigate the effects of curcumin on the amyloidogenic pathway of APP in vitro. Plasmids APPswe and BACE1-mychis were transiently co-transfected into SH-SY5Y and HEK293 cells. Then, they were treated with curcumin at 0, 1.25, 5, 20 μmol/L for 24 h, or with curcumin at 5μmol/L for 0, 12, 24 and 48 h for the time course assay. Our findings showed that curcumin could inhibit the expression of the APP at mRNA level; the expression of the BACE1 and C99 at mRNA and protein levels, furthermore it could inhibit the generation of Aβ40/42, and those changes were dose-time dependent (p<0.05). Our study indicates that Aβ40/42 generation inhibition effect of curcumin might due to its influence on amyloidogenic pathway. This may provide important experimental basis for AD treatment with curcumin.

Abstract 221: miR-19b Protects Myocardial Ischemia Reperfusion Injury

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Dongchao Lv ◽  
Shengguang Ding ◽  
Ping Chen ◽  
Yihua Bei ◽  
Chongjun Zhong ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Cellular Proliferation ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
H9c2 Cells ◽  
Protein Levels ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion ◽  
Induced Apoptosis

Ischemia-reperfusion injury (IRI) following acute myocardial infarction (AMI) has no effective treatment and a poor prognosis. microRNA (miRNA)-19b is a key functional member of miRNA-19-72 cluster family, regulating cellular proliferation, apoptosis, differentiation, and metabolism. Dysregulation of the miR-19b cluster is critically involved in a spectrum of cardiovascular diseases. However, the role of miR-19b in myocardial IRI is unknown. In this study, we found that miR-19b was downregulated in a mouse model of IRI. Meanwhile, about 50% downregulation of miR-19b was detected in H2O2-treated H9C2 cells mimicking myocardial IRI. We also found that overexpression of miR-19b decreased H2O2-induced apoptosis (36.02%±3.92% vs 29.34%±0.79% in nc-mimics vs miR-19b-mimics, respectively) and necrosis (23.11%±1.64% vs 18.76%±0.71% in nc-mimics vs miR-19b-mimics, respectively), and increased proliferation of H9C2 cells in vitro, while downregulation of miR-19b had reverse effects. Furthermore, PTEN, a previously validated target gene of miR-19b, has been found to be negatively regulated by miR-19b at protein levels in H9C2 cells. These data reveal the potential of miR-19b as a therapeutic target for myocardial IRI.

scholarly journals NFκB activation and stimulation of chemokine production in normal human macrophages by the gadolinium-based magnetic resonance contrast agent Omniscan: possible role in the pathogenesis of nephrogenic systemic fibrosis

2010 ◽  
Vol 69 (11) ◽  
pp. 2024-2033 ◽  
Author(s):  
Francesco Del Galdo ◽  
Peter J Wermuth ◽  
Sankar Addya ◽  
Paolo Fortina ◽  
Sergio A Jimenez
Keyword(s):  
Gene Expression ◽  
Nephrogenic Systemic Fibrosis ◽  
Specific Cell ◽  
Chemokine Production ◽  
Nuclear Localisation ◽  
Inos Protein ◽  
Protein Levels ◽  
Normal Human ◽  
Stimulation Of

ObjectiveNephrogenic systemic fibrosis (NSF) is a generalised fibrotic disorder occurring in certain individuals with renal insufficiency exposed to gadolinium-based contrast agents (GdBCA) for MRI. Histopathological examination of affected tissues shows increased numbers of activated macrophages. To elucidate the mechanisms responsible for macrophage activation, the effects of the GdBCA Omniscan on normal human macrophage global gene expression, chemokine production and nuclear factor κB (NFκB) activation was examined.MethodsNormal human monocyte-derived macrophages were incubated with Omniscan (50 mM) and their gene expression analysed by microarrays and real-time PCR. Macrophage chemokine production was assayed by multiplex ELISA. NFκB activation was assessed by NFκB nuclear localisation and quantitation of intracellular levels of inducible nitric oxide synthase (iNOS) protein. A specific cell-permeable NFκB peptide inhibitor was used to abrogate NFκB stimulation of chemokine and iNOS protein levels. CCL8/MCP-2 in affected skin of patients with NSF was examined by indirect immunofluorescence.ResultsOmniscan caused a profound change in the transcriptome of differentiated human normal macrophages in vitro, including a large increase in the expression of genes encoding CC and CXC chemokines. It induced rapid nuclear localisation of NFκB and stimulation of iNOS protein levels and chemokine production which were blocked by an NFκB inhibitory peptide. CCL8/MCP-2, the most upregulated chemokine following in vitro macrophage exposure to Omniscan, was strongly increased in NSF-affected skin.ConclusionThe GdBCA Omniscan induces potent stimulation of macrophage gene expression, NFκB activation and increased NFκB-mediated production of CC and CXC chemokines and iNOS. These alterations may play a crucial role in the pathogenesis of NSF.

scholarly journals Regulation of Hypoxia-Induced Cell Death in Human Tenocytes

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Min Liang ◽  
Hannah R. Cornell ◽  
Nasim Zargar Baboldashti ◽  
Mark S. Thompson ◽  
Andrew J. Carr ◽  
...  
Keyword(s):  
Cellular Response ◽  
Platelet Rich Plasma ◽  
Cell Types ◽  
Antiapoptotic Proteins ◽  
Vascular Growth Factor ◽  
Protective Strategy ◽  
Normal Human ◽  
Induced Apoptosis ◽  
Oxygen Requirements

Degenerate shoulder tendons display evidence of hypoxia. However tendons are relatively avascular and not considered to have high oxygen requirements and the vulnerability of tendon cells to hypoxia is unclear. Cultured human tenocytes were exposed to hypoxia and the cellular response detected using QPCR, Western blotting, viability, and ELISA assays. We find that tenocytes respond to hypoxiain vitroby activating classical HIF-1α-driven pathways. Total hypoxia caused significant tenocyte apoptosis. Transcription factors typically involved in hypoxic response, HIF-1αand FOXO3A, were upregulated. Hypoxia caused sustained upregulation of several proapoptotic proteins known to mediate hypoxia-induced apoptosis, such as Bnip3 and Nix, but others were unchanged although they were reportedly hypoxia-sensitive in other cell types. Antiapoptotic proteins Bcl2 and Bcl-xL were unchanged by hypoxia. Normal human tenocytes expressed all isoforms of the hypoxia-induced vascular growth factor VEGF except VEGF-D. Hypoxia markedly upregulated VEGF-A mRNA, followed by increased VEGF protein secretion. However treatment with VEGF did not improve tenocyte survival. As a protective strategy for tenocytes at risk of hypoxic death we added prosurvival growth factors insulin or platelet rich plasma (PRP). Both agents strongly protected tenocytes from hypoxia-induced death over 48 h, suggesting possible efficacy in the acute postrupture tendon or integrating graft.

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