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Constance JE, Despres SD, Nishida A, Lim CS. Selective targeting of c-Abl via a cryptic mitochondrial targeting signal activated by cellular redox status in leukemic and breast cancer cells. Pharm Res 2012; 29:2317-28. [PMID: 22549737 DOI: 10.1007/s11095-012-0758-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 04/11/2012] [Indexed: 01/03/2023]
Abstract
PURPOSE The tyrosine kinase c-Abl localizes to the mitochondria under cell stress conditions and promotes apoptosis. However, c-Abl has not been directly targeted to the mitochondria. Fusing c-Abl to a mitochondrial translocation signal (MTS) that is activated by reactive oxygen species (ROS) will selectively target the mitochondria of cancer cells exhibiting an elevated ROS phenotype. Mitochondrially targeted c-Abl will thereby induce malignant cell death. METHODS Confocal microscopy was used to determine mitochondrial colocalization of ectopically expressed c-Abl-EGFP/cMTS fusion across three cell lines (K562, Cos-7, and 1471.1) with varying levels of basal (and pharmacologically modulated) ROS. ROS were quantified by indicator dye assay. The functional consequences of mitochondrial c-Abl were assessed by DNA accessibility to 7-AAD using flow cytometry. RESULTS The cMTS and cMTS/c-Abl fusions colocalized to the mitochondria in leukemic (K562) and breast (1471.1) cancer phenotypes (but not Cos-7 fibroblasts) in a ROS and PKC dependent manner. CONCLUSIONS We confirm and extend oxidative stress activated translocation of the cMTS by demonstrating that the cMTS and Abl/cMTS fusion selectively target the mitochondria of K562 leukemia and mammary adenocarcinoma 1471.1 cells. c-Abl induced K562 leukemia cell death when targeted to the matrix but not the outer membrane of the mitochondria.
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Affiliation(s)
- Jonathan E Constance
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108, USA.
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52
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Cao Y, Zhao Z, Eckert RL, Reece EA. The essential role of protein kinase Cδ in diabetes-induced neural tube defects. J Matern Fetal Neonatal Med 2012; 25:2020-4. [PMID: 22463764 DOI: 10.3109/14767058.2012.677963] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Maternal diabetes causes neural tube defects (NTDs) in the embryos via activating protein kinase Cs (PKCs), which regulate programmed cell death (apoptosis). The aims of this study are to investigate the role of proapoptotic PKCδ in NTD formation and the underlying mechanisms. METHODS PKCδ heterozygous (pkcδ(+/-)) female mice were diabetic (DM) induced by intravenous injection of streptozotocin. Occurrence of NTDs was evaluated at embryonic day 11.5 and compared between wild type (WT) and PKCδ homozygous (pkcδ(-/-)) embryos. Changes in oxidative and endoplasmic reticulum (ER) stress-associated factors and stress-response c-Jun N-terminal kinases (JNKs) were assessed using Western blot assay. RESULTS Compared to DM/WT, the DM/PKCδ(-/-) embryos had significantly lower NTD rate and lower levels of oxidative and ER stress factors and JNK activation. These values were similar to those in the non-diabetic control group. CONCLUSION PKCδ plays a critical role in diabetes-induced NTDs, potentially through increasing oxidative and ER stress and JNK-associated stress-response pathways.
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Affiliation(s)
- Yuanning Cao
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Abstract
Given the functional importance of the endoplasmic reticulum (ER), an organelle that performs folding, modification, and trafficking of secretory and membrane proteins to the Golgi compartment, the maintenance of ER homeostasis in insulin-secreting β-cells is very important. When ER homeostasis is disrupted, the ER generates adaptive signaling pathways, called the unfolded protein response (UPR), to maintain homeostasis of this organelle. However, if homeostasis fails to be restored, the ER initiates death signaling pathways. New observations suggest that both chronic hyperglycemia and hyperlipidemia, known as important causative factors of type 2 diabetes (T2D), disrupt ER homeostasis to induce unresolvable UPR activation and β-cell death. This review examines how the UPR pathways, induced by high glucose and free fatty acids (FFAs), interact to disrupt ER function and cause β-cell dysfunction and death.
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Affiliation(s)
- Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan, Republic of Korea 680-749
| | - Randal J. Kaufman
- Degenerative Disease Research Program, Neuroscience, Aging, and Stem Cell Research Center, Sanford Burnham Medical Research Institute, La Jolla, California 92037
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Jäger R, Bertrand MJM, Gorman AM, Vandenabeele P, Samali A. The unfolded protein response at the crossroads of cellular life and death during endoplasmic reticulum stress. Biol Cell 2012; 104:259-70. [PMID: 22268789 DOI: 10.1111/boc.201100055] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 01/18/2012] [Indexed: 12/14/2022]
Abstract
One of the early cellular responses to endoplasmic reticulum (ER) stress is the activation of the unfolded protein response (UPR). ER stress and the UPR are both implicated in numerous human diseases and pathologies. In spite of this, our knowledge of the molecular mechanisms that regulate cell fate following ER stress is limited. The UPR is initiated by three ER transmembrane receptors: PKR-like ER kinase (PERK), activating transcription factor (ATF) 6 and inositol-requiring enzyme 1 (IRE1). These proteins sense the accumulation of unfolded proteins and their activation triggers specific adaptive responses to resolve the stress. Intriguingly, the very same receptors can initiate signalling pathways that lead to apoptosis when the attempts to resolve the ER stress fail. In this review, we describe the known pro-apoptotic signalling pathways emanating from activated PERK, ATF6 and IRE1 and discuss how their signalling switches from an adaptive to a pro-apoptotic response.
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Affiliation(s)
- Richard Jäger
- Apoptosis Research Centre, National University of Ireland Galway, Galway, Ireland
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55
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Protein kinase C beta in postischemic brain mitochondria. Mitochondrion 2012; 12:138-43. [DOI: 10.1016/j.mito.2011.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 04/06/2011] [Accepted: 06/10/2011] [Indexed: 11/23/2022]
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56
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Ranta F, Leveringhaus J, Theilig D, Schulz-Raffelt G, Hennige AM, Hildebrand DG, Handrick R, Jendrossek V, Bosch F, Schulze-Osthoff K, Häring HU, Ullrich S. Protein kinase C delta (PKCδ) affects proliferation of insulin-secreting cells by promoting nuclear extrusion of the cell cycle inhibitor p21Cip1/WAF1. PLoS One 2011; 6:e28828. [PMID: 22216119 PMCID: PMC3246440 DOI: 10.1371/journal.pone.0028828] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 11/15/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND High fat diet-induced hyperglycemia and palmitate-stimulated apoptosis was prevented by specific inhibition of protein kinase C delta (PKCδ) in β-cells. To understand the role of PKCδ in more detail the impact of changes in PKCδ activity on proliferation and survival of insulin-secreting cells was analyzed under stress-free conditions. METHODOLOGY AND PRINCIPAL FINDINGS Using genetic and pharmacological approaches, the effect of reduced and increased PKCδ activity on proliferation, apoptosis and cell cycle regulation of insulin secreting cells was examined. Proteins were analyzed by Western blotting and by confocal laser scanning microscopy. Increased expression of wild type PKCδ (PKCδWT) significantly stimulated proliferation of INS-1E cells with concomitant reduced expression and cytosolic retraction of the cell cycle inhibitor p21(Cip1/WAF1). This nuclear extrusion was mediated by PKCδ-dependent phosphorylation of p21(Cip1/WAF1) at Ser146. In kinase dead PKCδ (PKCδKN) overexpressing cells and after inhibition of endogenous PKCδ activity by rottlerin or RNA interference phosphorylation of p21(Cip1/WAF1) was reduced, which favored its nuclear accumulation and apoptotic cell death of INS-1E cells. Human and mouse islet cells express p21(Cip1/WAF1) with strong nuclear accumulation, while in islet cells of PKCδWT transgenic mice the inhibitor resides cytosolic. CONCLUSIONS AND SIGNIFICANCE These observations disclose PKCδ as negative regulator of p21(Cip1/WAF1), which facilitates proliferation of insulin secreting cells under stress-free conditions and suggest that additional stress-induced changes push PKCδ into its known pro-apoptotic role.
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Affiliation(s)
- Felicia Ranta
- Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - Johannes Leveringhaus
- Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - Dorothea Theilig
- Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - Gabriele Schulz-Raffelt
- Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - Anita M. Hennige
- Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - Dominic G. Hildebrand
- Interfaculty Institute for Biochemistry (IFIB), University of Tübingen, Tübingen, Germany
| | - René Handrick
- Institute for Pharmaceutical Biotechnology, Biberach University of Applied Sciences, Biberach, Germany
| | | | - Fatima Bosch
- Center of Animal Biotechnology and Gene Therapy, Universita Autònoma Barcelona, Bellaterra and CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Klaus Schulze-Osthoff
- Interfaculty Institute for Biochemistry (IFIB), University of Tübingen, Tübingen, Germany
| | - Hans-Ulrich Häring
- Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - Susanne Ullrich
- Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
- * E-mail:
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Zheng H, Liu J, Liu C, Lu F, Zhao Y, Jin Z, Ren H, Leng X, Jia J, Hu G, Dong S, Zhong X, Li H, Yang B, Xu C, Zhang W. Calcium-sensing receptor activating phosphorylation of PKCδ translocation on mitochondria to induce cardiomyocyte apoptosis during ischemia/reperfusion. Mol Cell Biochem 2011; 358:335-43. [DOI: 10.1007/s11010-011-0984-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 07/06/2011] [Indexed: 12/15/2022]
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Kim J, Koyanagi T, Mochly-Rosen D. PKCδ activation mediates angiogenesis via NADPH oxidase activity in PC-3 prostate cancer cells. Prostate 2011; 71:946-54. [PMID: 21541971 PMCID: PMC3544470 DOI: 10.1002/pros.21310] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 10/21/2010] [Indexed: 11/07/2022]
Abstract
BACKGROUND PKCδ is generally known as a pro-apoptotic and anti-proliferative enzyme in human prostate cancer cells. METHODS Here, we investigated the role of PKCδ on the growth of PC-3 human prostate cancer cells in vivo and in vitro. RESULTS We found that sustained treatment with a specific PKCδ activator (ψδ receptor for active C kinase, ψδRACK) increased growth of PC-3 xenografts. There was increased levels of HIF-1α, vascular endothelial growth factor and CD31-positive cells in PC-3 xenografts, representative of increased tumor angiogenesis. Mechanistically, PKCδ activation increased the levels of reactive oxygen species (ROS) by binding to and phosphorylating NADPH oxidase, which induced its activity. Also, PKCδ-induced activation of NADPH oxidase increased the level of HIF-1α. CONCLUSIONS Our results using tumors from the PC-3 xenograft model suggest that PKCδ activation increases angiogenic activity in androgen-independent PC-3 prostate cancer cells by increasing NADPH oxidase activity and HIF-1α levels and thus may partly be responsible for increased angiogenesis in advanced prostate cancer.
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Affiliation(s)
- Jeewon Kim
- Department of Chemical and Systems Biology, Stanford University, School of Medicine, Stanford, CA, 94305
| | - Tomoyoshi Koyanagi
- Department of Chemical and Systems Biology, Stanford University, School of Medicine, Stanford, CA, 94305
| | - Daria Mochly-Rosen
- Department of Chemical and Systems Biology, Stanford University, School of Medicine, Stanford, CA, 94305
- Address for all correspondence: Daria Mochly-Rosen, Department of Chemical and Systems Biology, Stanford University, School of Medicine, Stanford, CA, 94305-5174, Tel: 650-725-7720, Fax: 650-723-4686,
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Bezy O, Tran TT, Pihlajamäki J, Suzuki R, Emanuelli B, Winnay J, Mori MA, Haas J, Biddinger SB, Leitges M, Goldfine AB, Patti ME, King GL, Kahn CR. PKCδ regulates hepatic insulin sensitivity and hepatosteatosis in mice and humans. J Clin Invest 2011; 121:2504-17. [PMID: 21576825 DOI: 10.1172/jci46045] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 03/30/2011] [Indexed: 12/27/2022] Open
Abstract
C57BL/6J and 129S6/Sv (B6 and 129) mice differ dramatically in their susceptibility to developing diabetes in response to diet- or genetically induced insulin resistance. A major locus contributing to this difference has been mapped to a region on mouse chromosome 14 that contains the gene encoding PKCδ. Here, we found that PKCδ expression in liver was 2-fold higher in B6 versus 129 mice from birth and was further increased in B6 but not 129 mice in response to a high-fat diet. PRKCD gene expression was also elevated in obese humans and was positively correlated with fasting glucose and circulating triglycerides. Mice with global or liver-specific inactivation of the Prkcd gene displayed increased hepatic insulin signaling and reduced expression of gluconeogenic and lipogenic enzymes. This resulted in increased insulin-induced suppression of hepatic gluconeogenesis, improved glucose tolerance, and reduced hepatosteatosis with aging. Conversely, mice with liver-specific overexpression of PKCδ developed hepatic insulin resistance characterized by decreased insulin signaling, enhanced lipogenic gene expression, and hepatosteatosis. Therefore, changes in the expression and regulation of PKCδ between strains of mice and in obese humans play an important role in the genetic risk of hepatic insulin resistance, glucose intolerance, and hepatosteatosis; and thus PKCδ may be a potential target in the treatment of metabolic syndrome.
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Affiliation(s)
- Olivier Bezy
- Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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60
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Wang H, Xiao L, Kazanietz MG. p23/Tmp21 associates with protein kinase Cdelta (PKCdelta) and modulates its apoptotic function. J Biol Chem 2011; 286:15821-15831. [PMID: 21454541 PMCID: PMC3091192 DOI: 10.1074/jbc.m111.227991] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 03/14/2011] [Indexed: 02/05/2023] Open
Abstract
There is emerging evidence that C1 domains, motifs originally identified in PKC isozymes and responsible for binding of phorbol esters and diacylglycerol, interact with the Golgi/endoplasmic reticulum protein p23 (Tmp21). In this study, we investigated whether PKCδ, a kinase widely implicated in apoptosis and inhibition of cell cycle progression, associates with p23 and determined the potential functional implications of this interaction. Using a yeast two-hybrid approach, we found that the PKCδ C1b domain associates with p23 and identified two key residues (Asp(245) and Met(266)) implicated in this interaction. Interestingly, silencing p23 from LNCaP prostate cancer cells using RNAi markedly enhanced PKCδ-dependent apoptosis and activation of PKCδ downstream effectors ROCK and JNK by phorbol 12-myristate 13-acetate. Moreover, translocation of PKCδ to the plasma membrane by phorbol 12-myristate 13-acetate was enhanced in p23-depleted LNCaP cells. Notably, a PKCδ mutant that failed to interact with p23 triggered a strong apoptotic response when expressed in LNCaP cells. In summary, our data compellingly support the concept that C1 domains have dual roles both in lipid and protein associations and provide strong evidence that p23 acts as an anchoring protein that retains PKCδ at the perinuclear region, thus limiting the availability of this kinase for activation in response to stimuli.
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Affiliation(s)
- HongBin Wang
- From the Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160
| | - Liqing Xiao
- From the Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160
| | - Marcelo G. Kazanietz
- From the Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6160
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Zhou W, Brush MH, Choy MS, Shenolikar S. Association with endoplasmic reticulum promotes proteasomal degradation of GADD34 protein. J Biol Chem 2011; 286:21687-96. [PMID: 21518769 DOI: 10.1074/jbc.m110.212787] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Stress-induced endogenous and ectopically expressed GADD34 proteins were present both in the cytoplasm and in membranes, with their membrane association showing similar biochemical properties. Deletion of N-terminal sequences in GADD34-GFP proteins highlighted an amphipathic helix, whose hydrophobic surface, specifically valine 25 and leucine 29, mediated endoplasmic reticulum (ER) localization. Substitution of leucines for three arginines on the polar surface indicated that the same helix also mediated the association of GADD34 with mitochondria. Fluorescence protease protection and chemical modification of cysteines substituted in the membrane-binding domain pointed to a monotopic insertion of GADD34 into the outer layer of the ER membrane. Fluorescence recovery after photobleaching showed that ER association retards the mobility of GADD34 in living cells. Both WT GADD34 and the mutant, V25R, effectively scaffolded the α-isoform of protein phosphatase-1 (PP1α) and enabled eIF2α dephosphorylation. However, the largely cytosolic V25R protein displayed a reduced rate of proteasomal degradation, and unlike WT GADD34, whose ectopic expression resulted in a dilated or distended ER, V25R did not modify ER morphology. These studies suggested that the association of with ER modulates intracellular trafficking and proteasomal degradation of GADD34, and in turn, its ability to modify ER morphology.
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Affiliation(s)
- Wei Zhou
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore 169857
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Liu S, Yuan Q, Zhao S, Wang J, Guo Y, Wang F, Zhang Y, Liu Q, Zhang S, Ling EA, Hao A. High glucose induces apoptosis in embryonic neural progenitor cells by a pathway involving protein PKCδ. Cell Signal 2011; 23:1366-74. [PMID: 21440619 DOI: 10.1016/j.cellsig.2011.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 03/15/2011] [Accepted: 03/18/2011] [Indexed: 11/29/2022]
Abstract
Diabetic-induced neural tube defects in embryos are caused by apoptosis of neural progenitor cells (NPCs); however, the underlying mechanisms are poorly understood. The present study is aimed to investigate the specific cellular proteins that may be involved in apoptosis of NPCs. We show here that hyperglycemia-induced apoptosis of NPCs was through a PKCδ-dependent mechanism. Tyrosine phosphorylation of PKCδ was required for PKCδ binding to c-Abl in the cytoplasm, and inhibition of c-Abl by STI571 or knock-down of c-Abl by RNAi decreased the phosphorylation of PKCδ. Moreover, translocation of PKCδ and c-Abl complex from the cytoplasm to the nucleus, was blocked by down-regulation of PKCδ or c-Abl. Furthermore, we found that interaction of PKCδ and c-Abl played a crucial role in p53 accumulation in the nucleus, which was linked to the apoptosis of NPCs in response to high glucose.
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Affiliation(s)
- Shangming Liu
- Department of Histology and Embryology, Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University School of Medicine, 44#, Wenhua Xi Road, Jinan, Shandong, 250012, PR China
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Protein tyrosine phosphatase interacting protein 51--a jack-of-all-trades protein. Cell Tissue Res 2011; 344:189-205. [PMID: 21369858 DOI: 10.1007/s00441-011-1146-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 02/05/2011] [Indexed: 01/30/2023]
Abstract
Protein tyrosine phosphatase interacting protein 51 (PTPIP51) interacts both in vitro and in vivo with PTP1B, a protein tyrosine phosphatase involved in cellular regulation. PTPIP51 is known to be expressed in many different types of tissues. It is involved in cellular processes such as proliferation, differentiation and apoptosis. Nevertheless, the exact cellular function of PTPIP51 is still unknown. The present review summarizes our current knowledge of the PTPIP51 gene and its mRNA and protein structure.
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Mancini M, Corradi V, Petta S, Barbieri E, Manetti F, Botta M, Santucci MA. A new nonpeptidic inhibitor of 14-3-3 induces apoptotic cell death in chronic myeloid leukemia sensitive or resistant to imatinib. J Pharmacol Exp Ther 2011; 336:596-604. [PMID: 21041536 DOI: 10.1124/jpet.110.172536] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Resistance of chronic myeloid leukemia (CML) to tyrosine kinase inhibitor imatinib mesylate (IM) is most often due to point mutations in the Bcr-Abl fusion gene. T315I mutation (resulting in substitution of Ile for a Thr residue at the "gatekeeper" position 315) raises particular concern, because it also provides resistance to second-generation kinase inhibitors already approved for clinical use (nilotinib and dasatinib). Much effort is therefore focused on alternative molecular-based strategies. Previous studies proved that binding to 14-3-3 scaffolding proteins leads to cytoplasmic compartmentalization and suppression of proapoptotic and antiproliferative signals associated with Bcr-Abl protein kinase, hence contributing to leukemic clone expansion. Here we investigated the effect of 14-3-3 inhibition disruption on hematopoietic cells expressing the IM-sensitive wild type Bcr-Abl and the IM-resistant T315I mutation. Using a virtual screening protocol and docking simulations, we identified a nonpeptidic inhibitor of 14-3-3, named BV02, that exhibits a remarkable cytotoxicity against both cell types. c-Abl release from 14-3-3σ, promoting its relocation to nuclear compartment (where it triggers transcription of p73-dependent proapoptotic genes) and to mitochondrial membranes (where it induces the loss of mitochondrial transmembrane potential) combined with c-Abl enhanced association with caspase 9 (a critical step of sequential caspase activation further contributing to c-Abl pro-apoptotic function) has a prominent role in the effect of BV02 on Bcr-Abl-expressing cells. In conclusion, BV02 may be considered as a treatment option for CML and, in particular, for more advanced phases of the disease that developed IM resistance as a consequence of Bcr-Abl point mutations.
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MESH Headings
- 14-3-3 Proteins/antagonists & inhibitors
- 14-3-3 Proteins/chemistry
- Amino Acid Sequence
- Animals
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Apoptosis/physiology
- Benzamides/chemistry
- Benzamides/pharmacology
- Benzamides/therapeutic use
- Binding Sites/drug effects
- Binding Sites/physiology
- Cell Death/drug effects
- Cell Death/physiology
- Cell Line
- Cell Line, Tumor
- Crystallography, X-Ray
- Drug Resistance, Neoplasm/physiology
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Mice
- Molecular Sequence Data
- Piperazines/pharmacology
- Piperazines/therapeutic use
- Pyrazoles/chemistry
- Pyrazoles/pharmacology
- Pyrazoles/therapeutic use
- Pyrimidines/pharmacology
- Pyrimidines/therapeutic use
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Affiliation(s)
- Manuela Mancini
- Dipartimento di Ematologia e Scienze Oncologiche Lorenzo e Ariosto Seràgnoli, Policlinico S. Orsola, Bologna, Italy
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Cantley J, Boslem E, Laybutt DR, Cordery DV, Pearson G, Carpenter L, Leitges M, Biden TJ. Deletion of protein kinase Cδ in mice modulates stability of inflammatory genes and protects against cytokine-stimulated beta cell death in vitro and in vivo. Diabetologia 2011; 54:380-9. [PMID: 21103982 DOI: 10.1007/s00125-010-1962-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 10/06/2010] [Indexed: 12/23/2022]
Abstract
AIMS/HYPOTHESIS Proinflammatory cytokines contribute to beta cell destruction in type 1 diabetes, but the mechanisms are incompletely understood. The aim of the current study was to address the role of the protein kinase C (PKC) isoform PKCδ, a diverse regulator of cell death, in cytokine-stimulated apoptosis in primary beta cells. METHODS Islets isolated from wild-type or Prkcd(-/-) mice were treated with IL-1β, TNF-α and IFNγ and assayed for apoptosis, nitric oxide (NO) generation and insulin secretion. Activation of signalling pathways, apoptosis and endoplasmic reticulum (ER) stress were determined by immunoblotting. Stabilisation of mRNA transcripts was measured by RT-PCR following transcriptional arrest. Mice were injected with multiple low doses of streptozotocin (MLD-STZ) and fasting blood glucose monitored. RESULTS Deletion of Prkcd inhibited apoptosis and NO generation in islets stimulated ex vivo with cytokines. It also delayed the onset of hyperglycaemia in MLD-STZ-treated mice. Activation of ERK, p38, JNK, AKT1, the ER stress markers DDIT3 and phospho-EIF2α and the intrinsic apoptotic markers BCL2 and MCL1 was not different between genotypes. However, deletion of Prkcd destabilised mRNA transcripts for Nos2, and for multiple components of the toll-like receptor 2 (TLR2) signalling complex, which resulted in disrupted TLR2 signalling. CONCLUSIONS/INTERPRETATION Loss of PKCδ partially protects against hyperglycaemia in the MLD-STZ model in vivo, and against cytokine-mediated apoptosis in vitro. This is accompanied by reduced NO generation and destabilisation of Nos2 and components of the TLR2 signalling pathway. The results highlight a mechanism for regulating proinflammatory gene expression in beta cells independently of transcription.
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Affiliation(s)
- J Cantley
- Garvan Institute of Medical Research, St Vincent's Hospital, 384 Victoria Street, Darlinghurst, Sydney, NSW 2010, Australia
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66
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Tamura N, Sugihara K, Akama TO, Fukuda MN. Trophinin-mediated cell adhesion induces apoptosis of human endometrial epithelial cells through PKC-δ. Cell Cycle 2011; 10:135-43. [PMID: 21191175 DOI: 10.4161/cc.10.1.14448] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Trophinin is an intrinsic membrane protein expressed in trophectoderm cells of embryos and in uterine epithelial cells. Trophinin potentially mediates apical cell adhesion at human embryo implantation sites through trophinin-trophinin binding in these two cell types. Trophinin-mediated cell adhesion activates trophectoderm cells for invasion, whereas the effect of adhesion on maternal side is not known. We show that addition of GWRQ peptide, a previously established peptide that mimics trophinin-mediated cell adhesion, to human endometrial epithelial cells expressing trophinin induces their apoptosis. FAS involvement was excluded, as GWRQ did not bind to FAS, and FAS knockdown did not alter GWRQ-induced apoptosis. Immunoblotting analyses of protein kinases revealed an elevation of PKC-d protein in GWRQ-bound endometrial epithelial cells. In the absence of GWRQ, PKC-d associated with trophinin and remained cytoplasmic, but after GWRQ binding to the trophinin extracellular domain, PKC-d became tyrosine phosphorylated, dissociated from trophinin, and entered the nucleus. In PKC-d knockdown endometrial cells, GWRQ did not induce apoptosis.
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Affiliation(s)
- Naoaki Tamura
- Tumor Microenvironment Program, Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
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67
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Kajimoto T, Sawamura S, Tohyama Y, Mori Y, Newton AC. Protein kinase C {delta}-specific activity reporter reveals agonist-evoked nuclear activity controlled by Src family of kinases. J Biol Chem 2010; 285:41896-910. [PMID: 20959447 PMCID: PMC3009917 DOI: 10.1074/jbc.m110.184028] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 10/18/2010] [Indexed: 12/20/2022] Open
Abstract
Conventional and novel protein kinase C (PKC) isozymes transduce the abundance of signals mediated by phospholipid hydrolysis; however redundancy in regulatory mechanisms confounds dissecting the unique signaling properties of each of the eight isozymes constituting these two subgroups. Previously, we created a genetically encoded reporter (C kinase activity reporter (CKAR)) to visualize the rate, amplitude, and duration of agonist-evoked PKC signaling at specific locations within the cell. Here we designed a reporter, δCKAR, that specifically measures the activation signature of one PKC isozyme, PKC δ, in cells, revealing unique spatial and regulatory properties of this isozyme. Specifically, we show two mechanisms of activation: 1) agonist-stimulated activation at the plasma membrane (the site of most robust PKC δ signaling), Golgi, and mitochondria that is independent of Src and can be triggered by phorbol esters and 2) agonist-stimulated activation in the nucleus that requires Src kinase activation and cannot be triggered by phorbol esters. Translocation studies reveal that the G-protein-coupled receptor agonist UTP induces the translocation of PKC δ into the nucleus by a mechanism that depends on the C2 domain and requires Src kinase activity. However, translocation from the cytosol into the nucleus is not required for the Src-dependent regulation of nuclear activity; a construct of PKC δ prelocalized to the nucleus continues to be activated by UTP by a mechanism dependent on Src kinase activity. These data identify the nucleus as a signaling hub for PKC δ that is driven by receptor-mediated signaling pathways (but not phorbol esters) and differs from signaling at plasma membrane and Golgi in that it is controlled by Src family kinases.
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Affiliation(s)
- Taketoshi Kajimoto
- From the Department of Pharmacology, University of California at San Diego, La Jolla, California 92093
- the Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan, and
| | - Seishiro Sawamura
- the Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan, and
| | - Yumi Tohyama
- the Division of Biochemistry, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kamiohno, Himeji, Hyogo 670-8524, Japan
| | - Yasuo Mori
- the Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan, and
| | - Alexandra C. Newton
- From the Department of Pharmacology, University of California at San Diego, La Jolla, California 92093
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68
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Qi X, Disatnik MH, Shen N, Sobel RA, Mochly-Rosen D. Aberrant mitochondrial fission in neurons induced by protein kinase C{delta} under oxidative stress conditions in vivo. Mol Biol Cell 2010; 22:256-65. [PMID: 21119009 PMCID: PMC3020920 DOI: 10.1091/mbc.e10-06-0551] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Neuronal cell death in a number of neurological disorders is associated with aberrant mitochondrial dynamics and mitochondrial degeneration. However, the triggers for this mitochondrial dysregulation are not known. Here we show excessive mitochondrial fission and mitochondrial structural disarray in brains of hypertensive rats with hypertension-induced brain injury (encephalopathy). We found that activation of protein kinase Cδ (PKCδ) induced aberrant mitochondrial fragmentation and impaired mitochondrial function in cultured SH-SY5Y neuronal cells and in this rat model of hypertension-induced encephalopathy. Immunoprecipitation studies indicate that PKCδ binds Drp1, a major mitochondrial fission protein, and phosphorylates Drp1 at Ser 579, thus increasing mitochondrial fragmentation. Further, we found that Drp1 Ser 579 phosphorylation by PKCδ is associated with Drp1 translocation to the mitochondria under oxidative stress. Importantly, inhibition of PKCδ, using a selective PKCδ peptide inhibitor (δV1-1), reduced mitochondrial fission and fragmentation and conferred neuronal protection in vivo and in culture. Our study suggests that PKCδ activation dysregulates the mitochondrial fission machinery and induces aberrant mitochondrial fission, thus contributing to neurological pathology.
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Affiliation(s)
- Xin Qi
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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69
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Colabardini AC, De Castro PA, De Gouvêa PF, Savoldi M, Malavazi I, Goldman MHS, Goldman GH. Involvement of the Aspergillus nidulans protein kinase C with farnesol tolerance is related to the unfolded protein response. Mol Microbiol 2010; 78:1259-79. [PMID: 21091509 DOI: 10.1111/j.1365-2958.2010.07403.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Previously, we demonstrated that the Aspergillus nidulans calC2 mutation in protein kinase C pkcA was able to confer tolerance to farnesol (FOH), an isoprenoid that has been shown to inhibit proliferation and induce apoptosis. Here, we investigate in more detail the role played by A. nidulans pkcA in FOH tolerance. We demonstrate that pkcA overexpression during FOH exposure causes increased cell death. FOH is also able to activate several markers of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). Our results suggest an intense cross-talk between PkcA and the UPR during FOH-induced cell death. Furthermore, the overexpression of pkcA increases both mRNA accumulation and metacaspases activity, and there is a genetic interaction between PkcA and the caspase-like protein CasA. Mutant analyses imply that MAP kinases are involved in the signal transduction in response to the effects caused by FOH.
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Affiliation(s)
- Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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Wang CL, Shim WB, Shaw BD. Aspergillus nidulans striatin (StrA) mediates sexual development and localizes to the endoplasmic reticulum. Fungal Genet Biol 2010; 47:789-99. [PMID: 20601045 DOI: 10.1016/j.fgb.2010.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 06/12/2010] [Accepted: 06/15/2010] [Indexed: 01/20/2023]
Abstract
Striatin family proteins have been identified in animals and fungi and are considered to be scaffolding proteins. In fungi striatin orthologs have been associated with sexual development and virulence to plants. In this study, we characterized the functions and localization of the striatin ortholog, StrA, in Aspergillus nidulans. deltastrA strains showed multiple defects in conidium germination, mycelial radial growth, production of diffusible red pigment, and reduced conidiation. The most striking phenotype is the production of abnormally small cleistothecia that are defective in ascosporogenesis. Over-expression of strA enhanced cleistothecium development and increased the production of Hülle cells in shaking liquid cultures. In addition, we generated strains expressing StrA::eGFP under the endogenous promoter. By co-labeling with FM4-64 and co-localization with nuclear localized StuA(NLS)::DsRed or CxnA (an endoplasmic reticulum marker), we determined that StrA mainly localizes to endoplasmic reticulum and the nuclear envelope.
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Affiliation(s)
- Chih-Li Wang
- Program for the Biology of Filamentous Fungi, Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA
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71
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Li X, Pabla N, Wei Q, Dong G, Messing RO, Wang CY, Dong Z. PKC-delta promotes renal tubular cell apoptosis associated with proteinuria. J Am Soc Nephrol 2010; 21:1115-24. [PMID: 20395372 DOI: 10.1681/asn.2009070760] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Proteinuria may contribute to progressive renal damage by inducing tubulointerstitial inflammation, fibrosis, and tubular cell injury and death, but the mechanisms underlying these pathologic changes remain largely unknown. Here, in a rat kidney proximal tubular cell line (RPTC), albumin induced apoptosis in a time- and dose-dependent manner. Caspase activation accompanied albumin-induced apoptosis, and general caspase inhibitors could suppress this activation. In addition, Bcl-2 transfection inhibited apoptosis and attenuated albumin-induced Bax translocation to mitochondria and cytochrome c release from the organelles, further confirming a role for the intrinsic pathway of apoptosis in albuminuria-associated tubular apoptosis. We observed phosphorylation and activation of PKC-delta early during treatment of RPTC cells with albumin. Rottlerin, a pharmacologic inhibitor of PKC-delta, suppressed albumin-induced Bax translocation, cytochrome c release, and apoptosis. Moreover, a dominant-negative mutant of PKC-delta blocked albumin-induced apoptosis in RPTC cells. In vivo, we observed activated PKC-delta in proteinuric kidneys of streptozotocin-induced diabetic mice and in kidneys after direct albumin overload. Notably, albumin overload induced apoptosis in renal tubules, which was less severe in PKC-delta-knockout mice. Taken together, these results suggest that activation of PKC-delta promotes tubular cell injury and death during albuminuria, broadening our understanding of the pathogenesis of progressive proteinuric kidney diseases.
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Affiliation(s)
- Xiaoning Li
- Department of Cellular Biology and Anatomy, Medical College of Georgia and Charlie Norwood Veterans' Affairs Medical Center, Augusta, Georgia 30912, USA
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The protein kinase C agonist PEP005 (ingenol 3-angelate) in the treatment of human cancer: a balance between efficacy and toxicity. Toxins (Basel) 2010; 2:174-94. [PMID: 22069553 PMCID: PMC3206618 DOI: 10.3390/toxins2010174] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 01/07/2010] [Accepted: 01/18/2010] [Indexed: 12/31/2022] Open
Abstract
The diterpene ester ingenol-3-angelate (referred to as PEP005) is derived from the plant Euphorbia peplus. Crude euphorbia extract causes local toxicity and transient inflammation when applied topically and has been used in the treatment of warts, skin keratoses and skin cancer. PEP005 is a broad range activator of the classical (α, β, γ) and novel (δ, ε, η, θ) protein kinase C isoenzymes. Direct pro-apoptotic effects of this drug have been demonstrated in several malignant cells, including melanoma cell lines and primary human acute myelogenous leukemia cells. At micromolar concentrations required to kill melanoma cells this agent causes PKC-independent secondary necrosis. In contrast, the killing of leukemic cells occurs in the nanomolar range, requires activation of protein kinase C δ (PKCδ) and is specifically associated with translocation of PKCδ from the cytoplasm to the nuclear membrane. However, in addition to this pro-apoptotic effect the agent seems to have immunostimulatory effects, including: (i) increased chemokine release by malignant cells; (ii) a general increase in proliferation and cytokine release by activated T cells, including T cells derived from patients with chemotherapy-induced lymphopenia; (iii) local infiltration of neutrophils after topical application with increased antibody-dependent cytotoxicity; and (iv) development of specific anti-cancer immune responses by CD8(+) T cells in animal models. Published studies mainly describe effects from in vitro investigations or after topical application of the agent, and careful evaluation of the toxicity after systemic administration is required before the possible use of this agent in the treatment of malignancies other than skin cancers.
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73
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Qvit N, Mochly-Rosen D. Highly Specific Modulators of Protein Kinase C Localization: Applications to Heart Failure. DRUG DISCOVERY TODAY. DISEASE MECHANISMS 2010; 7:e87-e93. [PMID: 21151743 PMCID: PMC2998291 DOI: 10.1016/j.ddmec.2010.07.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Heart failure (HF) in which the blood supply does not match the body's needs, affects 10% of the population over 65 years old. The protein kinase C (PKC) family of kinases has a key role in normal and disease states. Here we discuss the role of PKC in HF and focus on the use of specific PKC regulators to identify the mechanism leading to this Pathology and potential leads for therapeutics.
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Affiliation(s)
- Nir Qvit
- Department of Chemical and Systems Biology, Stanford University, School of Medicine, Stanford CA 94305-5174
| | - Daria Mochly-Rosen
- Department of Chemical and Systems Biology, Stanford University, School of Medicine, Stanford CA 94305-5174
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74
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Hennige AM, Ranta F, Heinzelmann I, Düfer M, Michael D, Braumüller H, Lutz SZ, Lammers R, Drews G, Bosch F, Häring HU, Ullrich S. Overexpression of kinase-negative protein kinase Cdelta in pancreatic beta-cells protects mice from diet-induced glucose intolerance and beta-cell dysfunction. Diabetes 2010; 59:119-27. [PMID: 19826167 PMCID: PMC2797912 DOI: 10.2337/db09-0512] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE In vitro models suggest that free fatty acid-induced apoptotic beta-cell death is mediated through protein kinase C (PKC)delta. To examine the role of PKCdelta signaling in vivo, transgenic mice overexpressing a kinase-negative PKCdelta (PKCdeltaKN) selectively in beta-cells were generated and analyzed for glucose homeostasis and beta-cell survival. RESEARCH DESIGN AND METHODS Mice were fed a standard or high-fat diet (HFD). Blood glucose and insulin levels were determined after glucose loads. Islet size, cleaved caspase-3, and PKCdelta expression were estimated by immunohistochemistry. In isolated islet cells apoptosis was assessed with TUNEL/TO-PRO3 DNA staining and the mitochondrial potential by rhodamine-123 staining. Changes in phosphorylation and subcellular distribution of forkhead box class O1 (FOXO1) were analyzed by Western blotting and immunohistochemistry. RESULTS PKCdeltaKN mice were protected from HFD-induced glucose intolerance. This was accompanied by increased insulin levels in vivo, by an increased islet size, and by a reduced staining of beta-cells for cleaved caspase-3 compared with wild-type littermates. In accordance, long-term treatment with palmitate increased apoptotic cell death of isolated islet cells from wild-type but not from PKCdeltaKN mice. PKCdeltaKN overexpression protected islet cells from palmitate-induced mitochondrial dysfunction and inhibited nuclear accumulation of FOXO1 in mouse islet and INS-1E cells. The inhibition of nuclear accumulation of FOXO1 by PKCdeltaKN was accompanied by an increased phosphorylation of FOXO1 at Ser256 and a significant reduction of FOXO1 protein. CONCLUSIONS Overexpression of PKCdeltaKN in beta-cells protects from HFD-induced beta-cell failure in vivo by a mechanism that involves inhibition of fatty acid-mediated apoptosis, inhibition of mitochondrial dysfunction, and inhibition of FOXO1 activation.
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Affiliation(s)
- Anita M. Hennige
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
| | - Felicia Ranta
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
| | - Isabel Heinzelmann
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
| | - Martina Düfer
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Diana Michael
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
| | - Heidi Braumüller
- Department of Dermatology, University of Tübingen, Tübingen, Germany
| | - Stefan Z. Lutz
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
| | - Reiner Lammers
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
| | - Gisela Drews
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Fatima Bosch
- Center of Animal Biotechnology and Gene Therapy, Universita Autònoma Barcelona, and CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Barcelona, Spain
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
| | - Susanne Ullrich
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Vascular Medicine, Nephrology, and Clinical Chemistry, University of Tübingen, Tübingen, Germany
- Corresponding author: Susanne Ullrich,
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Affiliation(s)
- Carsten Schmitz-Peiffer
- Garvan Institute of Medical Research, Sydney, Australia
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
| | - Trevor J. Biden
- Garvan Institute of Medical Research, Sydney, Australia
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, Australia
- Corresponding author: Trevor J. Biden,
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76
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TNFalpha activation of PKCdelta, mediated by NFkappaB and ER stress, cross-talks with the insulin signaling cascade. Cell Signal 2009; 22:274-84. [PMID: 19782747 DOI: 10.1016/j.cellsig.2009.09.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 09/14/2009] [Indexed: 02/06/2023]
Abstract
TNFalpha plays key roles in the regulation of inflammation, cell death, and proliferation and its signaling cascade cross-talks with the insulin signaling cascade. PKCdelta, a novel PKC isoform, is known to participate in proximal TNFalpha signaling events. However, it has remained unclear whether PKCdelta plays a role in distal TNFalpha signaling events. Here we demonstrate that PKCdelta is activated by TNFalpha in a delayed fashion that is temporally associated with JNK activation. To investigate the signaling pathways activating PKCdelta and JNK, we used pharmacological and genetic inhibitors of NFkappaB. We found that inhibition of NFkappaB attenuated PKCdelta and JNK activations. Further analysis revealed that ER stress contributes to TNFalpha-stimulated PKCdelta and JNK activations. To investigate the role of PKCdelta in TNFalpha action, we used 29-mer shRNAs to silence PKCdelta expression. A reduction of ~90% in PKCdelta protein levels reduced TNFalpha-stimulated stress kinase activation, including JNK. Further, PKCdelta was necessary for thapsigargin-stimulated JNK activation. Because thapsigargin is a potent inducer of ER stress, we determined whether PKCdelta was necessary for induction of the UPR. Indeed, a reduction in PKCdelta protein levels reduced thapsigargin-stimulated CHOP induction, a hallmark of the UPR, but not BiP/GRP78 induction, suggesting that PKCdelta does not globally regulate the UPR. Next, the role of PKCdelta in TNFalpha mediated cross-talk with the insulin signaling pathway was investigated in cells expressing human IRS-1 and a 29-mer shRNA to silence PKCdelta expression. We found that a reduction in PKCdelta protein levels reversed the TNFalpha-mediated reduction in insulin-stimulated IRS-1 Tyr phosphorylation, Akt activation, and glycogen synthesis. In addition, TNFalpha-stimulated IRS protein Ser/Thr phosphorylation and degradation were blocked. Our results indicate that: 1) NFkappaB and ER stress contribute in part to PKCdelta activation; 2) PKCdelta plays a key role in the propagation of the TNFalpha signal; and 3) PKCdelta contributes to TNFalpha-induced inhibition of insulin signaling events.
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Sallese M, Giannotta M, Luini A. Coordination of the secretory compartments via inter-organelle signalling. Semin Cell Dev Biol 2009; 20:801-9. [PMID: 19447052 DOI: 10.1016/j.semcdb.2009.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 04/01/2009] [Accepted: 04/03/2009] [Indexed: 11/18/2022]
Abstract
Over the last decade, accumulating data have demonstrated the presence of 'classical' signalling molecules on endomembranes, including endosomes and the Golgi complex. It is now clear that through these signalling molecules, endomembranes can serve two functions: one is to elaborate and relay signalling initiated at the plasma membrane, and the other is to initiate new signalling in response to stimuli originating from the endomembranes themselves. Here, we have examined this emerging paradigm, with particular emphasis on a novel Golgi-based signalling cascade. This system senses, and is activated by, endoplasmic reticulum chaperones that arrive at the Golgi complex during constitutive secretion; these bind to the KDEL receptor and activate the Src family kinases. These, in turn, positively regulate the intra-Golgi transport machinery. This system thus coordinates the initiating process, the membrane input, with an increased membrane output. In more general terms, it responds with signals to an endogenous event. In this respect, it is similar to the unfolded protein response, a complex cell reaction to the accumulation of unfolded proteins in the endoplasmic reticulum, that is, to our knowledge the only other examples of inter-organelle signalling initiated within the cell. However, in contrast to the Golgi-based signalling pathway, this unfolded protein signalling is generally activated by pathological conditions. We propose that inter-organelle signalling is a mechanism by which different compartments of eukaryotic cells coordinate their functions.
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Affiliation(s)
- Michele Sallese
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, 66030 Santa Maria Imbaro, CH, Italy.
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Friedman B, Schachtrup C, Tsai PS, Shih AY, Akassoglou K, Kleinfeld D, Lyden PD. Acute vascular disruption and aquaporin 4 loss after stroke. Stroke 2009; 40:2182-90. [PMID: 19372455 PMCID: PMC2753985 DOI: 10.1161/strokeaha.108.523720] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 12/22/2008] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Ischemic protection has been demonstrated by a decrease in stroke-infarct size in transgenic mice with deficient Aquaporin 4 (AQP4) expression. However, it is not known whether AQP4 is rapidly reduced during acute stroke in animals with normal AQP4 phenotype, which may provide a potential self-protective mechanism. METHODS Adult male rats underwent transient occlusion of the middle cerebral artery (tMCAo) for 1 to 8 hours followed by reperfusion for 30 minutes. Protein and mRNA expression of AQP4 and glial fibrillary acidic protein (GFAP) were determined by Western blot and rtPCR. Fluorescence quantitation was obtained with laser scanning cytometry (LSC) for Cy5-tagged immunoreactivity along with fluorescein signals from pathological uptake of plasma-borne high-molecular-weight fluorescein-dextran. Cell death was assessed with in vivo Propidium Iodide (PI) nucleus labeling. RESULTS In the ischemic hemisphere in tissue sections, patches of fluorescein-dextran uptake were overlapped with sites of focal loss of AQP4 immunoreactivity after tMCAo of 1 to 8 hours duration. However, the average levels of AQP4 protein and mRNA, determined in homogenates of whole striatum, were not significantly reduced after 8 hours of tMCAo. Tissue section cytometry (LSC) of immunoreactivity in scan areas with high densities of fluorescein-dextran uptake demonstrated reductions in AQP4, but not in IgG or GFAP, after tMCAo of 2 hours or longer. Scan areas with low densities of fluorescein-dextran did not lose AQP4. There was sparse astrocyte cell death as only 1.7+/-0.85% (mean, SD) of DAPI labeled cells were PI- and GFAP-labeled after 8 hours of tMCAo. CONCLUSIONS During acute tMCAo, a rapid loss of AQP4 immunoreactivity from viable astrocytes can occur. However, AQP4 loss is spatially selective and occurs primarily in regions of vascular damage.
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Affiliation(s)
- Beth Friedman
- Department of Neurosciences, UCSD School of Medicine, San Diego, CA, USA
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79
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Wang F, Liu HM, Irwin MG, Xia ZY, Huang Z, Ouyang J, Xia Z. Role of protein kinase C β2 activation in TNF-α-induced human vascular endothelial cell apoptosis. Can J Physiol Pharmacol 2009; 87:221-9. [PMID: 19295663 DOI: 10.1139/y09-004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The circulatory inflammatory cytokine tumor necrosis factor alpha (TNF-α) is increased in pathologic conditions that initiate or exacerbate vascular endothelial injury, such as diabetes. Protein kinase C (PKC) has been shown to play a critical role in TNF-α-induced human endothelial cell apoptosis. However, the relative roles played by specific isoforms of PKC in TNF-α-induced human endothelial cell apoptosis have not been addressed. We investigated the effects of a selective PKCβ2 inhibitor (CGP53353) on TNF-α-induced apoptosis in human vascular endothelial cells (cell line ECV304) and on the production of reactive oxygen species and nitric oxide, and compared its effects with rottlerin, a reagent that has been shown to reduce PKCδ protein levels. Cultured human vascular endothelial cells (ECV304) were treated for 24 h with one of 4 regimes: 40 ng/mL TNF-α alone (TNF-α), TNF-α with 10 µmol/L rottlerin (T+rottlerin), TNF-α with 1 µmol/L CGP53353 (T+CGP), or untreated (control). Cell viability was measured by MTT assay, and cell apoptosis was assessed by flow cytometry. TNF-α-induced endothelial cell apoptosis was associated with dramatic increases in production of intracellular hydrogen peroxide (approximately 20 times greater than control) and superoxide (approximately 16 times greater than control), as measured by dichlorofluorescein and dihydroethidium fluorescent staining, respectively. This increase was accompanied by reduced activity of superoxide dismutase and glutathione peroxidase and, subsequently, an increase in the lipid peroxidation product malondialdehyde. CGP53353, but not rottlerin, abolished or attenuated all these changes. We conclude that PKCβ2 plays a major role in TNF-α-induced human vascular endothelial cell apoptosis.
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Affiliation(s)
- Fang Wang
- Anesthesiology Research Laboratory, Renmin Hospital, Wuhan University, Wuhan, Hubei, China
- Department of Anesthesiology, University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Pathophysiology, School of Medicine, Wuhan University, Wuhan, China
| | - Hui-min Liu
- Anesthesiology Research Laboratory, Renmin Hospital, Wuhan University, Wuhan, Hubei, China
- Department of Anesthesiology, University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Pathophysiology, School of Medicine, Wuhan University, Wuhan, China
| | - Michael G. Irwin
- Anesthesiology Research Laboratory, Renmin Hospital, Wuhan University, Wuhan, Hubei, China
- Department of Anesthesiology, University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Pathophysiology, School of Medicine, Wuhan University, Wuhan, China
| | - Zhong-yuan Xia
- Anesthesiology Research Laboratory, Renmin Hospital, Wuhan University, Wuhan, Hubei, China
- Department of Anesthesiology, University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Pathophysiology, School of Medicine, Wuhan University, Wuhan, China
| | - Zhiyong Huang
- Anesthesiology Research Laboratory, Renmin Hospital, Wuhan University, Wuhan, Hubei, China
- Department of Anesthesiology, University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Pathophysiology, School of Medicine, Wuhan University, Wuhan, China
| | - Jingping Ouyang
- Anesthesiology Research Laboratory, Renmin Hospital, Wuhan University, Wuhan, Hubei, China
- Department of Anesthesiology, University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Pathophysiology, School of Medicine, Wuhan University, Wuhan, China
| | - Zhengyuan Xia
- Anesthesiology Research Laboratory, Renmin Hospital, Wuhan University, Wuhan, Hubei, China
- Department of Anesthesiology, University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Pathophysiology, School of Medicine, Wuhan University, Wuhan, China
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Kowalczyk JE, Beresewicz M, Gajkowska B, Zabłocka B. Association of protein kinase C delta and phospholipid scramblase 3 in hippocampal mitochondria correlates with neuronal vulnerability to brain ischemia. Neurochem Int 2009; 55:157-63. [PMID: 19428821 DOI: 10.1016/j.neuint.2009.01.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 01/07/2009] [Accepted: 01/14/2009] [Indexed: 02/04/2023]
Abstract
Recent findings support the idea that mitochondrial integrity plays an important role in the propagation of excitotoxic ischemic signal and PKC is implicated in the regulation of mitochondrial membranes properties. One of the targets of PKC delta is phospholipid scramblase 3 (PLSCR3), an enzyme responsible for cardiolipin translocation from the inner to outer mitochondrial membrane. To get an insight into in vivo mechanism by which PKC delta mediates ischemia/reperfusion injury of hippocampal neurons, we examined the effects of transient brain ischemia in gerbil on association of PKC delta with mitochondria isolated from ischemia-vulnerable (CA1) and ischemia-resistant regions, and interactions between PKC delta and PLSCR3. Postischemic, biphasic and brain region-specific translocation of PKC delta to mitochondria was observed. First peak was at 30-60 min of reperfusion and the second was observed after 72-96 h following ischemia. PKC delta was translocated to mitochondria only in CA1 region. The PLSCR3 mRNA and protein was detected in brain by RT-PCR and sequence analysis, Western blotting and immunocytochemistry in electron microscopy (EM). Co-immunoprecipitation and double-labeled immuno-EM showed association of PKC delta and PLSCR3 in postischemic CA1 mitochondria. Additionally, the amount of tBid associated with mitochondria was elevated 96 h following ischemia. Our data suggest that in the postischemic brain PKC delta co-localizes with PLSCR3 in mitochondria and this event might influence the mitochondrial membranes architecture and delayed neurons degeneration.
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Affiliation(s)
- Joanna E Kowalczyk
- Molecular Biology Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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