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Shi M, Deng S, Cui Y, Chen X, Shi T, Song L, Zhang R, Zhang Y, Xu J, Shi J, Wang C, Li L. Repeated low-dose exposures to sarin disrupted the homeostasis of phospholipid and sphingolipid metabolism in guinea pig hippocampus. Toxicol Lett 2020; 338:32-39. [PMID: 33253782 DOI: 10.1016/j.toxlet.2020.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 01/22/2023]
Abstract
Repeated low-level exposure to sarin results to hippocampus dysfunction. Metabonomics involves a holistic analysis of a set of metabolites in an organism in the search for a relationship between these metabolites and physiological or pathological changes. The objective of the present study was to evaluate the effects of repeated exposure to low-level sarin on the metabonomics in hippocampus of a guinea pig model. Guinea pigs were divided randomly into control and sarin treated groups (n = 14). Guinea pigs in the control group received saline; while the sarin-treated group received 0.4×LD50 (16.8 μg/kg) sarin. Daily injections (a total of 14 days) were administered sc between the shoulder blades in a volume of 1.0 ml/kg body weight. At the end of the final injection, 6 animals in each group were chosen for Morris water maze test. The rest guinea pigs (n = 8 for each group) were sacrificed by decapitation, and hippocampus were dissected for analysis. Compared with the control-group, the escape latency in sarin-group was significantly (p < 0.05) longer while the crossing times were significantly decreased in the Morris water task (p < 0.05). Sarin inhibited activities of acetylcholinesterase (AChE) and neuropathy target esterase (NTE) in hippocampus. The AChE activity of hippocampus from sarin-treated groups is equivalent to 59.9 ± 6.4 %, and the NTE activity of hippocampus from sarin-groups is equivalent to 78.1 ± 8.3 % of that from control-group. Metabolites were identified and validated. A total of 14 variables were selected as potential biomarkers. Phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylinositol (PI), Lysophosphatidylethanolamine (LysoPE or LPE)] and sphingolipids (SPs) [sphinganine (SA), phytosphingosine (PSO) and sphinganine-1-phosphate (SA1P)] were clearly modified. In conclusion, repeated low-dose exposures to sarin disrupted the homeostasis of phospholipid and sphingolipid metabolism in guinea pig hippocampus and may lead to a neuronal-specific function disorders. Identified metabolites such as SA1P need to be studied more deeply on their biological function that against sarin lesions. In future research, we should pay more attention to characterize the physiological roles of lipid metabolism enzymes as well as their involvement in pathologies induced by repeated low-level sarin exposure.
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Affiliation(s)
- Meng Shi
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Shikun Deng
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Yalan Cui
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Xuejun Chen
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Tong Shi
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Liangcai Song
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Ruihua Zhang
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Yi Zhang
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Jianfu Xu
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Jingjing Shi
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China
| | - Chen Wang
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China.
| | - Liqin Li
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, PR China.
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Dinarelli S, Girasole M, Misiti F. Amyloid β peptide affects erythrocyte morphology: Role of intracellular signaling pathways. Clin Hemorheol Microcirc 2019; 71:437-449. [PMID: 31156152 DOI: 10.3233/ch-199007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Circulating red blood cells (RBCs) undergo aging, a fundamental physiological phenomenon that regulates their turnover. OBJECTIVE Understanding the role of Aβ in the cross talk between cell signalling pathways and modulation of the cell structural and biomechanical properties occurring in RBCs during aging. METHODS The morphological pattern has been monitored using Atomic Force Microscopy (AFM) imaging and measuring the RBCs' plasma membrane roughness employed as a morphological parameter capable to provide information on the structure and integrity of the membrane-skeleton. RESULTS We show that treatment with Aβ accelerates the occurrence of morphological and biochemical aging markers in human RBC and influences the cell metabolism. Biochemical data demonstrate that contemporaneously to morphological alterations, Aβ triggers: (i) metabolic alterations and (ii) a complex signaling pathway involving caspase 3, protein kinase C and nitric oxide derived metabolites. CONCLUSIONS our study provides a comprehensive picture in which Aβ treatment of RBC induces changes in specific cell signalling events and/or metabolic pathways, in turns affecting the membrane-cytoskeleton interaction and the membrane integrity.
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Affiliation(s)
- Simone Dinarelli
- Institute for the Structure of Matter (ISM), National Research Council (CNR), Rome, Italy
| | - Marco Girasole
- Institute for the Structure of Matter (ISM), National Research Council (CNR), Rome, Italy
| | - Francesco Misiti
- Human, Social and Health Department, University of Cassino and Lazio Meridionale, V. S. Angelo, Loc. Folcara, Cassino (FR), Italy
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Ma D, Wang P, Fang Q, Yu Z, Zhou Z, He Z, Wei D, Yu K, Lu T, Zhang Y, Wang J. Low-dose staurosporine selectively reverses BCR-ABL-independent IM resistance through PKC-α-mediated G2/M phase arrest in chronic myeloid leukaemia. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2019; 46:S208-S216. [PMID: 30618318 DOI: 10.1080/21691401.2018.1490310] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Dan Ma
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Ping Wang
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Qin Fang
- Department of Pharmacy, Affiliated Baiyun Hospital of Guizhou Medical University, Guiyang, China
- Department of Pharmacy, Affiliated Hospital of Guiyang Medical University, Guiyang, China
| | - Zhengyu Yu
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Zhen Zhou
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
- Department of Pharmacy, Affiliated Baiyun Hospital of Guizhou Medical University, Guiyang, China
- Department of Pharmacy, Affiliated Hospital of Guiyang Medical University, Guiyang, China
| | - Zhengchang He
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Danna Wei
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Kunling Yu
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Tingting Lu
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Yaming Zhang
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
| | - Jishi Wang
- Department of Hematology, Key Laboratory of Hematological Disease Diagnostic & Treat Centre of Guizhou Province, Affiliated Hospital of Guizhou Medical University, Guizhou Province Institute of Hematology, Guiyang, China
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4
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Kikkawa U. The story of PKC: A discovery marked by unexpected twists and turns. IUBMB Life 2018; 71:697-705. [PMID: 30393952 DOI: 10.1002/iub.1963] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 10/03/2018] [Accepted: 10/04/2018] [Indexed: 11/11/2022]
Abstract
Protein kinase C (PKC) is activated by 1,2-diacylglycerol as a second messenger in the signaling mechanism coupled with the hydrolysis of membrane inositol phospholipids, although it was not found by screening for a 1,2-diacylglycerol-dependent enzyme. PKC is also a receptor for the tumor-promoting phorbol esters, but it was not identified by its property of binding phorbol esters, either. Instead, the discovery and characterization of PKC, now known to comprise a family with multiple isoforms, was through a circuitous voyage filled with unexpected twists and turns. This review summarizes the discovery and the initial experiments of PKC as a historical perspective of the enzyme family in the context of the progress in the studies on protein phosphorylation. © 2018 IUBMB Life, 71(6):697-705, 2019.
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Affiliation(s)
- Ushio Kikkawa
- Biosignal Research Center, Kobe University, Kobe, Japan
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Carelli-Alinovi C, Dinarelli S, Sampaolese B, Misiti F, Girasole M. Morphological changes induced in erythrocyte by amyloid beta peptide and glucose depletion: A combined atomic force microscopy and biochemical study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:236-244. [PMID: 30040926 DOI: 10.1016/j.bbamem.2018.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 06/21/2018] [Accepted: 07/19/2018] [Indexed: 12/28/2022]
Abstract
Circulating red blood cells (RBCs) undergo aging, a fundamental physiological phenomenon that regulates their turnover. We show that treatment with beta amyloid peptide 1-42 (Aβ) accelerates the occurrence of morphological and biochemical aging markers in human RBCs and influences the cell metabolism leading to intracellular ATP depletion. The morphological pattern has been monitored using Atomic Force Microscopy (AFM) imaging and measuring the RBCs' plasma membrane roughness employed as a morphological parameter capable to provide information on the structure and integrity of the membrane-skeleton. Results evidence that Aβ boosts the development of crenatures and proto-spicules simultaneously to acceleration in the weakening of the cell-cytoskeleton contacts and to the induction of peculiar nanoscale features on the cell membrane. Incubation in the presence of glucose can remove all but the latter Aβ-induced effects. Biochemical data demonstrate that contemporaneously to morphological and structural alterations, Aβ and glucose depletion trigger a complex signaling pathway involving caspase 3, protein kinase C (PKC) and nitric oxide derived metabolites. As a whole, the collected data revealed that, the damaging path induced by Aβ in RBC provide a sequence of morphological and functional intermediates following one another along RBC life span, including: (i) an acceleration in the development of shape alteration typically observed along the RBC's aging; (ii) the development of characteristic membrane features on the plasma membrane and (iii) triggering a complex signaling pathway involving caspase 3, PKC and nitric oxide derived metabolites.
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Affiliation(s)
- Cristiana Carelli-Alinovi
- Biochemistry and Clinical Biochemistry Institute, Catholic University, School of Medicine, L. go F. Vito n.1, 00168 Rome, Italy
| | - Simone Dinarelli
- Institute for the Structure of the Matter (ISM), National Research Council (CNR), via Fosso del Cavaliere 100, 00133 Rome, Italy
| | - Beatrice Sampaolese
- Institute of Chemistry of the Molecular Recognition (ICRM), National Research Council (CNR), L. go F. Vito n.1, 00168 Rome, Italy
| | - Francesco Misiti
- Human, Social and Health Department, University of Cassino and Lazio Meridionale, V. S. Angelo, Loc. Folcara, 03043 Cassino, FR, Italy.
| | - Marco Girasole
- Institute for the Structure of the Matter (ISM), National Research Council (CNR), via Fosso del Cavaliere 100, 00133 Rome, Italy
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Kitessa SM, Abeywardena MY. Lipid-Induced Insulin Resistance in Skeletal Muscle: The Chase for the Culprit Goes from Total Intramuscular Fat to Lipid Intermediates, and Finally to Species of Lipid Intermediates. Nutrients 2016; 8:E466. [PMID: 27483311 PMCID: PMC4997379 DOI: 10.3390/nu8080466] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 07/13/2016] [Accepted: 07/21/2016] [Indexed: 12/16/2022] Open
Abstract
The skeletal muscle is the largest organ in the body. It plays a particularly pivotal role in glucose homeostasis, as it can account for up to 40% of the body and for up to 80%-90% of insulin-stimulated glucose disposal. Hence, insulin resistance (IR) in skeletal muscle has been a focus of much research and review. The fact that skeletal muscle IR precedes β-cell dysfunction makes it an ideal target for countering the diabetes epidemic. It is generally accepted that the accumulation of lipids in the skeletal muscle, due to dietary lipid oversupply, is closely linked with IR. Our understanding of this link between intramyocellular lipids (IMCL) and glycemic control has changed over the years. Initially, skeletal muscle IR was related to total IMCL. The inconsistencies in this explanation led to the discovery that particular lipid intermediates are more important than total IMCL. The two most commonly cited lipid intermediates for causing skeletal muscle IR are ceramides and diacylglycerol (DAG) in IMCL. Still, not all cases of IR and dysfunction in glycemic control have shown an increase in either or both of these lipids. In this review, we will summarise the latest research results that, using the lipidomics approach, have elucidated DAG and ceramide species that are involved in skeletal muscle IR in animal models and human subjects.
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Affiliation(s)
- Soressa M Kitessa
- CSIRO Health and Biosecurity, Kintore Avenue, Adelaide 5000, SA, Australia.
- Division of Livestock and Farming Systems, South Australian Research and Development Institute, J S Davies Bldg, Roseworthy Campus, GPO Box 397, Adelaide 5000, SA, Australia.
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Boneh A. Signal transduction in inherited metabolic disorders: a model for a possible pathogenetic mechanism. J Inherit Metab Dis 2015; 38:729-40. [PMID: 25735935 DOI: 10.1007/s10545-015-9820-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 01/20/2015] [Accepted: 02/02/2015] [Indexed: 01/08/2023]
Abstract
Signal transduction is the process by which external or internal signals exert their intracellular biological effects and by which intracellular communication is regulated. An important component of the signalling pathway is the second messenger, which is produced upon stimulation of the cell and mediates its effects downstream through phosphorylation and dephosphorylation of target proteins. Intracellular accumulation or deficiency of metabolites that serve as second messengers, due to inborn errors of their metabolism, may lead to perturbation of signalling pathways and disruption of the balance between them, serving as a missing link between the genotype, biochemical phenotype and clinical phenotype. The main second messengers that are putatively associated with the pathogenesis of IEM are 'bioactive lipids' (complex lipids and long-chain fatty acids), 'calcium', 'stress' (osmotic, reactive oxygen/nitorgen species, misfolded proteins and others) and 'metabolic' (AMP/ATP ratio, leucine, glutamine). They act through protein kinase C, calcium dependent kinases (CamK) and phosphatase (CN), 'stress-mediated' kinases (MAPK) and AMP/ATP-dependent kinase (AMPK). These signalling pathways lead to cell proliferation, inflammatory response, autophagy (and mitophagy) and apoptosis, suggesting that there are only few final common pathways involved in this pathogenetic mechanism. Questions remain regarding the complexity of the effects of the accumulating metabolites on different signalling pathways, and regarding the relative role and origin of 'proxy' second messengers such as reactive oxygen species. A better understanding of the signalling pathways in IEM may enhance the development of novel therapies in situations where normalising intracellular concentrations of the second messenger is impossible or impractical.
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Affiliation(s)
- Avihu Boneh
- Metabolic Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, Vic, 3052, Melbourne, Australia,
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8
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He X, Zang J, Li X, Shao J, Yang H, Yang J, Huang H, Chen L, Shi L, Zhu C, Zhang G, Zhou N. Activation of BNGR-A24 by direct interaction with tachykinin-related peptides from the silkworm Bombyx mori leads to the Gq- and Gs-coupled signaling cascades. Biochemistry 2014; 53:6667-78. [PMID: 25275886 DOI: 10.1021/bi5007207] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tachykinins constitute one of the largest peptide families in the animal kingdom and exert their diverse actions via G protein-coupled receptors (GPCRs). In this study, the Bombyx tachykinin-related peptides (TKRPs) were identified as specific endogenous ligands for the Bombyx neuropeptide GPCR A24 (BNGR-A24) and thus designated BNGR-A24 as BmTKRPR. Using both mammalian cell line HEK293 and insect cell line Sf21, further characterization demonstrated that BmTKRPR was activated, thus resulting in intracellular accumulation of cAMP, Ca(2+) mobilization, and ERK1/2 phosphorylation in a Gs and Gq inhibitor-sensitive manner. Moreover, quantitative reverse transcriptase polymerase chain reaction analysis and dsRNA-mediated knockdown experiments suggested a possible role for BmTKRPR in the regulation of feeding and growth. Our findings enhance the understanding of the Bombyx TKRP system in the regulation of fundamental physiological processes.
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Affiliation(s)
- Xiaobai He
- Institute of Biochemistry, College of Life Sciences, Zhejiang University , Zijingang Campus, Hangzhou, Zhejiang 310058, China
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Mencalha AL, Corrêa S, Abdelhay E. Role of calcium-dependent protein kinases in chronic myeloid leukemia: combined effects of PKC and BCR-ABL signaling on cellular alterations during leukemia development. Onco Targets Ther 2014; 7:1247-54. [PMID: 25045273 PMCID: PMC4099416 DOI: 10.2147/ott.s64303] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Calcium-dependent protein kinases (PKCs) function in a myriad of cellular processes, including cell-cycle regulation, proliferation, hematopoietic stem cell differentiation, apoptosis, and malignant transformation. PKC inhibitors, when targeted to these pathways, have demonstrated efficacy against several types of solid tumors as well as leukemia. Chronic myeloid leukemia (CML) represents 20% of all adult leukemia. The aberrant Philadelphia chromosome has been reported as the main cause of CML development in hematopoietic stem cells, due to the formation of the BCR-ABL oncogene. PKCs and BCR-ABL coordinate several signaling pathways that are crucial to cellular malignant transformation. Experimental and clinical evidence suggests that pharmacological approaches using PKC inhibitors may be effective in the treatment of CML. This mini review summarizes articles from the National Center for Biotechnology Information website that have shown evidence of the involvement of PKC in CML.
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Affiliation(s)
- André L Mencalha
- Biophysics and Biometry Department, Roberto Alcântara Gomes Biology Institute, Rio de Janeiro's State University (UERJ), Rio de Janeiro, Brazil
| | - Stephany Corrêa
- Bone Marrow Transplantation Unit (CEMO), National Cancer Institute (INCA), Rio de Janeiro, Brazil
| | - Eliana Abdelhay
- Bone Marrow Transplantation Unit (CEMO), National Cancer Institute (INCA), Rio de Janeiro, Brazil
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Anti-Chikungunya viral activities of aplysiatoxin-related compounds from the marine cyanobacterium Trichodesmium erythraeum. Mar Drugs 2014; 12:115-27. [PMID: 24394406 PMCID: PMC3917264 DOI: 10.3390/md12010115] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 11/25/2013] [Accepted: 12/12/2013] [Indexed: 11/21/2022] Open
Abstract
Tropical filamentous marine cyanobacteria have emerged as a viable source of novel bioactive natural products for drug discovery and development. In the present study, aplysiatoxin (1), debromoaplysiatoxin (2) and anhydrodebromoaplysiatoxin (3), as well as two new analogues, 3-methoxyaplysiatoxin (4) and 3-methoxydebromoaplysiatoxin (5), are reported for the first time from the marine cyanobacterium Trichodesmium erythraeum. The identification of the bloom-forming cyanobacterial strain was confirmed based on phylogenetic analysis of its 16S rRNA sequences. Structural determination of the new analogues was achieved by extensive NMR spectroscopic analysis and comparison with NMR spectral data of known compounds. In addition, the antiviral activities of these marine toxins were assessed using Chikungunya virus (CHIKV)-infected cells. Post-treatment experiments using the debrominated analogues, namely compounds 2, 3 and 5, displayed dose-dependent inhibition of CHIKV when tested at concentrations ranging from 0.1 µM to 10.0 µM. Furthermore, debromoaplysiatoxin (2) and 3-methoxydebromoaplysiatoxin (5) exhibited significant anti-CHIKV activities with EC50 values of 1.3 μM and 2.7 μM, respectively, and selectivity indices of 10.9 and 9.2, respectively.
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Barker CJ, Berggren PO. The pancreatic beta cell as a paradigm for advances in inositide research. Adv Biol Regul 2012; 52:361-368. [PMID: 22884029 DOI: 10.1016/j.jbior.2012.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 05/16/2012] [Indexed: 06/01/2023]
Abstract
In a previous review for Advances in Enzyme Research (Berggren and Barker, 2008) we outlined the history of our involvement in discovering important roles for inositides in the insulin secreting pancreatic beta cell. In this current appraisal we bring the work up to date and project how we believe this field will continue to develop in the future. Recently, we have seen an important synergism between the growth in our understanding of inositide function and our knowledge of beta cell stimulus-secretion coupling in both physiological and pathophysiological contexts. Important advances have been made in three areas. 1. The classic regulation of cytoplasmic free Ca(2+) concentration [Ca(2+)](i) by Inositol 1,4,5-trisphosphate (Ins(1,4,5)P(3)) and its receptor, 2. A novel role of the inositol pyrophosphates, especially 5-diphosphoinositol pentakisphosphate (5-PP-InsP(5)), in exocytosis, and 3. The unique signaling roles of PI3K pathways instituted by the engagement of the insulin receptor in an autocrine, positive feed-back loop. We examine each of these in turn and close with an assessment of the likely future directions the research will take.
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Affiliation(s)
- Christopher J Barker
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
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RamaRao G, Waghmare C, Kumar Gupta A, Bhattacharya BK. Soman-induced alterations of protein kinase C isozymes expression in five discrete areas of the rat brain. Drug Chem Toxicol 2011; 34:221-32. [DOI: 10.3109/01480545.2010.511647] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Sheremet YA, Yemets AI, Vissenberg K, Verbelen JP, Blume YB. Effects of inhibitors of serine/threonine protein kinases on Arabidopsis thaliana root morphology and microtubule organization in its cells. ACTA ACUST UNITED AC 2010. [DOI: 10.1134/s1990519x10040139] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Akhtar Khan N. Polyunsaturated fatty acids in the modulation of T-cell signalling. Prostaglandins Leukot Essent Fatty Acids 2010; 82:179-87. [PMID: 20189788 DOI: 10.1016/j.plefa.2010.02.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Indexed: 11/25/2022]
Abstract
n-3 polyunsaturated fatty acids (PUFA) have been shown to modulate immune responses. These agents, being considered as adjuvant immunosuppressants, have been used in the treatment of various inflammatory and autoimmune diseases. However, the molecular mechanisms of action of n-3 PUFA-induced immunosuppressive effects are not well-understood. Since exogenous n-3 PUFA, under in vitro and in vivo conditions, are efficiently incorporated into T-cell plasma membranes, a number of recent studies have demonstrated that these agents may modulate T-cell signalling. In this review, the interactions of n-3 PUFA with the second messenger cascade initiated during early and late events of T-cell activation are discussed. We particularly focus on how these fatty acids can modulate the production of diacylglycerol and the activation of protein kinase C, mitogen activated protein kinase, calcium signalling and translocation of transcriptional factors, implicated in the regulation of gene transcription in T-cells.
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Affiliation(s)
- Naim Akhtar Khan
- University of Burgundy, Department of Physiology, UPRES EA4183 Lipids and Cell Signalling, Faculty of Life Sciences, Dijon, France.
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Kim W, Khan NA, McMurray DN, Prior IA, Wang N, Chapkin RS. Regulatory activity of polyunsaturated fatty acids in T-cell signaling. Prog Lipid Res 2010; 49:250-61. [PMID: 20176053 DOI: 10.1016/j.plipres.2010.01.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 01/06/2010] [Accepted: 01/19/2010] [Indexed: 12/25/2022]
Abstract
n-3 Polyunsaturated fatty acids (PUFA) are considered to be authentic immunosuppressors and appear to exert beneficial effects with respect to certain immune-mediated diseases. In addition to promoting T-helper 1 (Th1) cell to T-helper 2 (Th2) cell effector T-cell differentiation, n-3 PUFA may also exert anti-inflammatory actions by inducing apoptosis in Th1 cells. With respect to mechanisms of action, effects range from the modulation of membrane receptors to gene transcription via perturbation of a number of second messenger cascades. In this review, the putative targets of anti-inflammatory n-3 PUFA, activated during early and late events of T-cell activation will be discussed. Studies have demonstrated that these fatty acids alter plasma membrane micro-organization (lipid rafts) at the immunological synapse, the site where T-cells and antigen-presenting cells (APC) form a physical contact for antigen initiated T-cell signaling. In addition, the production of diacylglycerol and the activation of different isoforms of protein kinase C (PKC), mitogen-activated protein kinase (MAPK), calcium signaling, and nuclear translocation/activation of transcriptional factors, can be modulated by n-3 PUFA. Advantages and limitations of diverse methodologies to study the membrane lipid raft hypothesis, as well as apparent contradictions regarding the effect of n-3 PUFA on lipid rafts will be critically presented.
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Affiliation(s)
- Wooki Kim
- Program in Integrative Nutrition and Complex Diseases, Center for Environmental and Rural Health, Texas A&M University, USA
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Giaroni C, Zanetti E, Pascale A, Oldrini R, Canciani L, Giuliani D, Amadio M, Chiaravalli AM, Lecchini S, Frigo GM. Involvement of Ca2+-dependent PKCs in the adaptive changes of mu-opioid pathways to sympathetic denervation in the guinea pig colon. Biochem Pharmacol 2009; 78:1233-41. [PMID: 19591807 DOI: 10.1016/j.bcp.2009.06.107] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 06/29/2009] [Accepted: 06/29/2009] [Indexed: 11/17/2022]
Abstract
In the guinea pig colon, chronic sympathetic denervation entails supersensitivity to inhibitory mu-opioid agents modulating cholinergic neurons. The mechanism underlying such adaptive change has not yet been unravelled, although protein kinase C (PKC) may be involved. A previous study indirectly demonstrated that activation of mu-opioid receptors on myenteric neurons facilitates PKC activity. Such coupling may counteract the inhibitory action of mu-opioid agents on acetylcholine overflow, since PKC, per se, increases this parameter. After chronic sympathetic denervation such restraint abates, representing a possible mechanism for development of supersensitivity to mu-opioid agents. In the present study, this hypothesis was further investigated. After chronic sympathetic denervation, Ca(2+)-dependent PKC activity was reduced in colonic myenteric plexus synaptosomes. The mu-opioid agent, DAMGO, increased Ca(2+)-dependent PKC activity in synaptosomes obtained from normal, but not from denervated animals. In myenteric synaptosomes obtained from this experimental group, protein levels of Ca(2+)-dependent PKC isoforms betaI, betaII and gamma decreased, whereas alpha levels increased. In whole-mount preparations, the four Ca(2+)-dependent PKC isoforms co-localized with mu-opioid receptors on subpopulations of colonic myenteric neurons. The percentage of neurons staining for PKCbetaII, as well as the number of mu-opioid receptor-positive neurons staining for PKCbetaII, decreased in denervated preparations. The same parameters related to PKCalpha, betaI or gamma remained unchanged. Overall, the present data strengthen the concept that mu-opioid receptors located on myenteric neurons are coupled to Ca(2+)-dependent PKCs. After chronic sympathetic denervation, a reduced efficiency of this coupling may predominantly involve PKCbetaII, although also PKCbetaI and gamma, but not PKCalpha, may be implicated.
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Affiliation(s)
- C Giaroni
- Department of Clinical Medicine, Section of Experimental and Clinical Pharmacology, University of Insubria, via O. Rossi 9, Varese, Italy.
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17
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Michell RH. First came the link between phosphoinositides and Ca2+ signalling, and then a deluge of other phosphoinositide functions. Cell Calcium 2009; 45:521-6. [DOI: 10.1016/j.ceca.2009.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 03/11/2009] [Indexed: 12/20/2022]
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18
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Diouf B, Collazos A, Labesse G, Macari F, Choquet A, Clair P, Gauthier-Rouvière C, Guérineau NC, Jay P, Hollande F, Joubert D. A 20-amino acid module of protein kinase C{epsilon} involved in translocation and selective targeting at cell-cell contacts. J Biol Chem 2009; 284:18808-15. [PMID: 19429675 DOI: 10.1074/jbc.m109.004614] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the pituitary gland, activated protein kinase C (PKC) isoforms accumulate either selectively at the cell-cell contact (alpha and epsilon) or at the entire plasma membrane (beta1 and delta). The molecular mechanisms underlying these various subcellular locations are not known. Here, we demonstrate the existence within PKCepsilon of a cell-cell contact targeting sequence (3CTS) that, upon stimulation, is capable of targeting PKCdelta, chimerin-alpha1, and the PKCepsilon C1 domain to the cell-cell contact. We show that this selective targeting of PKCepsilon is lost upon overexpression of 3CTS fused to a (R-Ahx-R)(4) (where Ahx is 6-aminohexanoic acid) vectorization peptide, reflecting a dominant-negative effect of the overexpressed 3CTS on targeting selectivity. 3CTS contains a putative amphipathic alpha-helix, a 14-3-3-binding site, and the Glu-374 amino acid, involved in targeting selectivity. We show that the integrity of the alpha-helix is important for translocation but that 14-3-3 is not involved in targeting selectivity. However, PKCepsilon translocation is increased when PKCepsilon/14-3-3 interaction is abolished, suggesting that phorbol 12-myristate 13-acetate activation may initiate two sets of PKCepsilon functions, those depending on 14-3-3 and those depending on translocation to cell-cell contacts. Thus, 3CTS is involved in the modulation of translocation via its 14-3-3-binding site, in cytoplasmic desequestration via the alpha-helix, and in selective PKCepsilon targeting at the cell-cell contact via Glu-374.
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Affiliation(s)
- Barthélémy Diouf
- CNRS UMR5203, INSERM, U661, University of Montpellier I and II, France
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19
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Holden NS, Squires PE, Kaur M, Bland R, Jones CE, Newton R. Phorbol ester-stimulated NF-kappaB-dependent transcription: roles for isoforms of novel protein kinase C. Cell Signal 2008; 20:1338-48. [PMID: 18436431 DOI: 10.1016/j.cellsig.2008.03.001] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Revised: 03/02/2008] [Accepted: 03/03/2008] [Indexed: 10/22/2022]
Abstract
Since protein kinase C (PKC) isoforms are variously implicated in the activation of NF-kappaB, we have investigated the role of PKC in the activation of NF-kappaB-dependent transcription by the diacyl glycerol (DAG) mimetic, phorbol 12-myristate 13-acetate (PMA), and by tumour necrosis factor (TNF) alpha in pulmonary A549 cells. The PKC selective inhibitors, Ro31-8220, Gö6976, GF109203X and Gö6983, revealed no effect on TNFalpha-induced NF-kappaB DNA binding and a similar lack of effect on serine 32/36 phosphorylated IkappaBalpha and the loss of total IkappaBalpha indicates that activation of the core IKK-IkappaBalpha-NF-kappaB cascade by TNFalpha does not involve PKC. In contrast, differential sensitivity of an NF-kappaB-dependent reporter to Ro31-8220, Gö6976, GF109203X and Gö6983 (EC(50)s 0.46 microM, 0.34 microM, >10 microM and >10 microM respectively) suggests a role for protein kinase D in transcriptional activation by TNFalpha. Compared with TNFalpha, PMA weakly induces NF-kappaB DNA binding and this effect was not associated with serine 32/36 phosphorylation of IkappaBalpha. However, PMA-stimulated NF-kappaB DNA binding was inhibited by Ro31-8220 (10 microM), GF109203X (10 microM) and Gö6983 (10 microM), but not by Gö6976 (10 microM), suggesting a role for novel PKC isoforms. Furthermore, a lack of positive effect of calcium mobilising agents on both NF-kappaB DNA binding and on transcriptional activation argues against major roles for classical PKCs. This, combined with the ability of both GF109203X and Gö6983 to prevent enhancement of TNFalpha-induced NF-kappaB-dependent transcription by PMA, further indicates a role for novel PKCs in NF-kappaB transactivation. Finally, siRNA-mediated knockdown of PKCdelta and epsilon expression did not affect TNFalpha-induced NF-kappaB-dependent transcription. However, knockdown of PKCdelta expression significantly inhibited PMA-stimulated luciferase activity, whereas knockdown of PKCepsilon was without effect. Furthermore, combined knockdown of PKCdelta and epsilon revealed an increased inhibitory effect on PMA-stimulated NF-kappaB-dependent transcription suggesting that PMA-induced NF-kappaB-dependent transcription is driven by novel PKC isoforms, particularly PKCdelta and epsilon.
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Affiliation(s)
- Neil S Holden
- Airways Inflammation Group, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
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20
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Nakajima T. Positive and negative regulation of radiation-induced apoptosis by protein kinase C. JOURNAL OF RADIATION RESEARCH 2008; 49:1-8. [PMID: 17785935 DOI: 10.1269/jrr.07053] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Indicators such as clonogenic survival, transformation, and chromosomal aberrations are used to evaluate the effects of radiation on cells. Apoptosis, another such indicator, is a mode of cell death, and radiation-induced apoptosis contributes to eliminating damaged cells and preventing malformation and carcinogenesis. Understanding radiation-induced apoptosis will assist in radiotherapy for cancer and treatment of patients in accidental radiation exposure. Protein kinase C (PKC) is a serine/threonine kinase that is related to cell proliferation, differentiation, metabolism, and apoptosis, and has many roles in the radiation-induced cellular responses involving apoptosis. This review describes the functions of PKC, including its relationship with other signaling networks and oxidative stress in the regulation of radiation-induced apoptosis. Such information might provide clues for evaluating the effects of radiation and for identifying clinical applications.
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Affiliation(s)
- Tetsuo Nakajima
- Radiation Effect Mechanisms Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, Japan.
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21
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Podar K, Raab MS, Chauhan D, Anderson KC. The therapeutic role of targeting protein kinase C in solid and hematologic malignancies. Expert Opin Investig Drugs 2007; 16:1693-707. [PMID: 17922632 DOI: 10.1517/13543784.16.10.1693] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The protein kinase C (PKC) family, the most prominent target of tumor-promoting phorbol esters, is functionally linked to cell differentiation, growth, survival, migration and tumorigenesis and so mediates tumor cell proliferation, survival, multidrug resistance, invasion, metastasis and tumor angiogenesis. Therefore, targeting PKC isozymes may represent an attractive target for novel anticancer therapies. Recent preclinical and clinical studies using the macrocyclic bisindolylmaleimide enzastaurin or the N-benzylstaurosporine midostaurin demonstrate promising activity of PKC inhibitors in a variety of tumors, including diffuse large B-cell lymphoma, multiple myeloma and Waldenstroem's macroglobulinemia. However, our knowledge of PKCs in tumorigenesis is still only partial and each PKC isoform may contribute to tumorigenesis in a distinct way. Specifically, PKC isoforms have vastly different roles, which vary depending on expression levels of organ and tissue distribution, cell type, intracellular localization, protein-protein and lipid-protein interactions and the biologic environment. Although PKC activation generally positively affects tumor cell growth, motility, invasion and metastasis, recent reports show that many PKCs can also have negative effects. Therefore, it is necessary to further dissect the relative contribution of PKC isozymes in the development and progression of specific tumors in order to identify therapeutic opportunities, using either PKC inhibitors or PKC activators.
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Affiliation(s)
- Klaus Podar
- Dana-Farber Cancer Institute, Department of Medical Oncology, Jerome Lipper Multiple Myeloma Center, 44 Binney Street, Boston, MA 02115, USA.
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22
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Santos ALSD, Soares RMDA. Effect of sphingosine and phorbol-12-myristate-13-acetate on the growth and dimethylsulfoxide-induced differentiation in the insect trypanosomatid Herpetomonas samuelpessoai. Mem Inst Oswaldo Cruz 2007; 102:601-4. [PMID: 17710305 DOI: 10.1590/s0074-02762007005000059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Accepted: 04/26/2007] [Indexed: 11/22/2022] Open
Abstract
We investigated the effect of two modulators of protein kinase C, sphingosine and phorbol-12-myristate-13-acetate (PMA), on the growth and dimethylsulfoxide (DMSO)-induced differentiation in Herpetomonas samuelpessoai. Sphingosine did not stimulate the transformation of undifferentiated-promastigotes in differentiated-paramastigotes. PMA alone or in association with DMSO increased the number of paramastigotes in comparison to control cells. DMSO inhibited the parasite growth (35%) and several unusual morphological features resembling aberrant cell division were observed. Sphingosine did not significantly reduce the growth in contrast to PMA. Collectively, our results demonstrated that the reduction of the proliferation translates in an increase of the differentiation rate in the insect trypanosomatid H. samuelpessoai.
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Affiliation(s)
- André Luis Souza dos Santos
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Universidade Federal do Rio de Janeiro, RJ, Fiocruz, Rio de Janeiro, RJ, Brasil.
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23
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Fuly AL, Machado AL, Castro P, Abrahão A, Redner P, Lopes UG, Guimarães JA, Koatz VLG. Lysophosphatidylcholine produced by the phospholipase A2 isolated from Lachesis muta snake venom modulates natural killer activity as a protein kinase C effector. Toxicon 2007; 50:400-10. [PMID: 17537472 DOI: 10.1016/j.toxicon.2007.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Accepted: 04/18/2007] [Indexed: 10/23/2022]
Abstract
We have showed that a phospholipase A(2) isolated from Lachesis muta snake venom, denoted LM-PLA(2)-I, had some biological effects. Here, we examined its effects on lymphocytes. Pre-incubation of human peripheral blood lymphocytes with LM-PLA(2)-I plus phosphatidylcholine (PC) stimulated the natural killer (NK) activity. This was accompanied by DNA binding of nuclear transcription factor kappaB and the increase in PKC activity with translocation of the enzyme from the cytoplasma into the plasma membrane. These effects were reproduced when lymphocytes were pre-incubated with commercial lysophosphatidylcholine (LPC) and abolished by stausrosporin or p-bromophenacyl bromide. Evaluation of phosphorylated PKC isoforms showed that pre-incubation with LPC activated the autophosphorylation of the PKCzeta isoform. Taken together, these results confirm that the enzymatic activity of the phospholipase A(2) present in L. muta venom is for the biological activity of the snake venom, and strongly suggest that the LPC produced may be acting as a modulator of PKC isoforms.
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Affiliation(s)
- André L Fuly
- Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Campus do Valonguinho s/n, Niterói, Rio de Janeiro 24210-150, Brazil.
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24
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Niemoeller OM, Bentzen PJ, Lang E, Lang F. Adenosine protects against suicidal erythrocyte death. Pflugers Arch 2007; 454:427-39. [PMID: 17285297 DOI: 10.1007/s00424-007-0218-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 11/21/2006] [Accepted: 01/19/2007] [Indexed: 01/13/2023]
Abstract
Suicidal death of erythrocytes or eryptosis is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine exposure at the erythrocyte surface. The cell membrane scrambling is triggered by an increase in cytosolic Ca(2+) activity and activation of protein kinase C (PKC). Phosphatidylserine exposure fosters adherence of affected erythrocytes to the vascular wall. Thus, microcirculation in ischemic tissues may be impaired by the appearance of eryptotic erythrocytes. Ischemia leads to release of adenosine, which in most tissues leads to vasodilation and protects against cell injury. The present experiments explored whether adenosine influences mechanisms underlying eryptosis. Erythrocyte phosphatidylserine exposure was estimated from annexin V binding, cell volume from forward scatter and cytosolic Ca(2+) activity from Fluo3 fluorescence. Glucose depletion (for 24 or 48 h) significantly increased annexin binding and decreased forward scatter, effects partially reversed by adenosine. The protective effect of adenosine reached statistical significance (s.d.) at > =30 microM. Low Cl(-) solution (Cl(-) exchanged by gluconate for 24 h) similarly increased annexin binding and decreased forward scatter, effects again reversed by adenosine (s.d. at > or =10 and 30 microM, respectively). Similarly, phosphatase inhibitor okadaic acid (OA, 1 microM) and PKC activator phorbol 12-myristate-13-acetate (PMA, 3 microM) significantly enhanced annexin binding and decreased forward scatter. Adenosine significantly blunted the effects of OA and PMA on annexin V binding (s.d. at > or =30 and 10 microM, respectively) and the effect of OA on forward scatter (s.d. at > or =10 microM). In conclusion, adenosine inhibits eryptosis by a mechanism presumably effective downstream of PKC. The effect may participate in the maintenance of microcirculation in ischemic tissue.
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25
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Oude Weernink PA, López de Jesús M, Schmidt M. Phospholipase D signaling: orchestration by PIP2 and small GTPases. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2007; 374:399-411. [PMID: 17245604 PMCID: PMC2020506 DOI: 10.1007/s00210-007-0131-4] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Accepted: 12/20/2006] [Indexed: 11/12/2022]
Abstract
Hydrolysis of phosphatidylcholine by phospholipase D (PLD) leads to the generation of the versatile lipid second messenger, phosphatidic acid (PA), which is involved in fundamental cellular processes, including membrane trafficking, actin cytoskeleton remodeling, cell proliferation and cell survival. PLD activity can be dramatically stimulated by a large number of cell surface receptors and is elaborately regulated by intracellular factors, including protein kinase C isoforms, small GTPases of the ARF, Rho and Ras families and, particularly, by the phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP(2)). PIP(2) is well known as substrate for the generation of second messengers by phospholipase C, but is now also understood to recruit and/or activate a variety of actin regulatory proteins, ion channels and other signaling proteins, including PLD, by direct interaction. The synthesis of PIP(2) by phosphoinositide 5-kinase (PIP5K) isoforms is tightly regulated by small GTPases and, interestingly, by PA as well, and the concerted formation of PIP(2) and PA has been shown to mediate receptor-regulated cellular events. This review highlights the regulation of PLD by membrane receptors, and describes how the close encounter of PLD and PIP5K isoforms with small GTPases permits the execution of specific cellular functions.
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Affiliation(s)
| | | | - Martina Schmidt
- />Department of Molecular Pharmacology, University of Groningen, A. Deusinglaan 1, 9713 AV Groningen, The Netherlands
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26
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Edling CE, Pedersen M, Carlsson L, Rönnstrand L, Palmer RH, Hallberg B. Haematopoietic progenitor cells utilise conventional PKC to suppress PKB/Akt activity in response to c-Kit stimulation. Br J Haematol 2007; 136:260-8. [PMID: 17156394 DOI: 10.1111/j.1365-2141.2006.06434.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Receptor tyrosine kinase (RTK) c-Kit signalling is crucial for the proliferation, survival and differentiation of haematopoietic stem cells (HSCs). To further understand the mechanisms underlying these events we explored how the downstream mediators interact. The present study investigated the function of conventional protein kinase Cs (c-PKC) in c-Kit mediated signalling pathways in HSC-like cell lines. This analysis supported earlier findings, that steel factor (SF) activates c-PKC, extracellular signal-regulated kinase (Erk) and protein kinase B (PKB). The present results were consistent with an important role of c-PKC in the positive activation of Erk and for proliferation. Further, it was observed that c-PKC negatively regulated PKB activity upon SF stimulation, indicating that c-PKC acts as a suppressor of c-Kit signalling. Finally, these observations were extended to show that c-PKC mediated the phosphorylation of the endogenous c-Kit receptor on serine 746, resulting in decreased overall tyrosine phosphorylation of c-Kit upon SF stimulation. This report showed that this specific feedback mechanism of c-PKC mediated phosphorylation of the c-Kit receptor has consequences for both proliferation and survival of HSC-like cell lines.
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Affiliation(s)
- Charlotte E Edling
- Department of Medical Biosciences/Pathology, Umeå University, Umeå, Sweden
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27
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Mahmmoud YA. Modulation of protein kinase C by curcumin; inhibition and activation switched by calcium ions. Br J Pharmacol 2006; 150:200-8. [PMID: 17160011 PMCID: PMC2042896 DOI: 10.1038/sj.bjp.0706970] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND AND PURPOSE Previous studies have identified the natural polyphenol curcumin as a protein kinase C (PKC) inhibitor. In contrast, we found significant stimulation of PKC activity following curcumin treatment. Thus, the mechanism of curcumin interaction with PKC was investigated. EXPERIMENTAL APPROACH We employed phosphorylation assays in the presence of soluble or membrane-bound PKC substrates, followed by SDS-PAGE, autoradiography and phosphorylation intensity measurements. KEY RESULTS Curcumin inhibited PKC in the absence of membranes whereas stimulation was observed in the presence of membranes. Further analysis indicated that curcumin decreased PKC activity by competition with Ca(2+) stimulation of the kinase, resulting in inhibition of activity at lower Ca(2+) concentrations and stimulation at higher Ca(2+) concentrations. The role of the membrane is likely to be facilitation of Ca(2+)-binding to the kinase, thus relieving the curcumin inhibition observed at limited Ca(2+) concentrations. Curcumin was found to mildly stimulate the catalytic subunit of PKC, which does not require Ca(2+) for activation. In addition, studies on Ca(2+)-independent PKC isoforms as well as another curcumin target (the sarcoplasmic reticulum Ca(2+)-ATPase) confirmed a correlation between Ca(2+) concentration and the curcumin effects. CONCLUSIONS AND IMPLICATIONS Curcumin competes with Ca(2+) for the regulatory domain of PKC, resulting in a Ca(2+)-dependent dual effect on the kinase. We propose that curcumin interacts with the Ca(2+)-binding domains in target proteins. To our knowledge, this is the first study that defines an interaction domain for curcumin, and provides a rationale for the broad specificity of this polyphenol as a chemopreventive drug.
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Affiliation(s)
- Y A Mahmmoud
- Institute of Physiology and Biophysics, Ole Worms Allé 1185, University of Aarhus, Aarhus C, Denmark.
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28
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Podar K, Raab MS, Zhang J, McMillin D, Breitkreutz I, Tai YT, Lin BK, Munshi N, Hideshima T, Chauhan D, Anderson KC. Targeting PKC in multiple myeloma: in vitro and in vivo effects of the novel, orally available small-molecule inhibitor enzastaurin (LY317615.HCl). Blood 2006; 109:1669-77. [PMID: 17023575 PMCID: PMC1794057 DOI: 10.1182/blood-2006-08-042747] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In multiple myeloma (MM) protein kinase C (PKC) signaling pathways have been implicated in cell proliferation, survival, and migration. Here we investigated the novel, orally available PKC-inhibitor enzastaurin for its anti-MM activity. Enzastaurin specifically inhibits phorbol ester-induced activation of PKC isoforms, as well as phosphorylation of downstream signaling molecules MARCKS and PKCmu. Importantly, it also inhibits PKC activation triggered by growth factors and cytokines secreted by bone marrow stromal cells (BMSCs), costimulation with fibronectin, vascular endothelial growth factor (VEGF), or interleukin-6 (IL-6), as well as MM patient serum. Consequently, enzastaurin inhibits proliferation, survival, and migration of MM cell lines and MM cells isolated from multidrug-resistant patients and overcomes MM-cell growth triggered by binding to BMSCs and endothelial cells. Importantly, strong synergistic cytotoxicity is observed when enzastaurin is combined with bortezomib and moderate synergistic or additive effects when combined with melphalan or lenalidomide. Finally, tumor growth, survival, and angiogenesis are abrogated by enzastaurin in an in vivo xenograft model of human MM. Our results therefore demonstrate in vitro and in vivo efficacy of the orally available PKC inhibitor enzastaurin in MM and strongly support its clinical evaluation, alone or in combination therapies, to improve outcome in patients with MM.
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Affiliation(s)
- Klaus Podar
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
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Oude Weernink PA, Han L, Jakobs KH, Schmidt M. Dynamic phospholipid signaling by G protein-coupled receptors. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1768:888-900. [PMID: 17054901 DOI: 10.1016/j.bbamem.2006.09.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 09/18/2006] [Accepted: 09/18/2006] [Indexed: 11/19/2022]
Abstract
G protein-coupled receptors (GPCRs) control a variety of fundamental cellular processes by regulating phospholipid signaling pathways. Essential for signaling by a large number of receptors is the hydrolysis of the membrane phosphoinositide PIP(2) by phospholipase C (PLC) into the second messengers IP(3) and DAG. Many receptors also stimulate phospholipase D (PLD), leading to the generation of the versatile lipid, phosphatidic acid. Particular PLC and PLD isoforms take differential positions in receptor signaling and are additionally regulated by small GTPases of the Ras, Rho and ARF families. It is now recognized that the PLC substrate, PIP(2), has signaling capacity by itself and can, by direct interaction, affect the activity and subcellular localization of PLD and several other proteins. As expected, the synthesis of PIP(2) by phosphoinositide 5-kinases is tightly regulated as well. In this review, we present an overview of how these signaling pathways are governed by GPCRs, explain the molecular basis for the spatially and temporally organized, highly dynamic quality of phospholipid signaling, and point to the functional connection of the pathways.
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Affiliation(s)
- Paschal A Oude Weernink
- Institut für Pharmakologie, Universitätsklinikum Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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30
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Abstract
Suicidal death of erythrocytes (eryptosis) is characterized by cell shrinkage, membrane blebbing, activation of proteases, and phosphatidylserine exposure at the outer membrane leaflet. Exposed phosphatidylserine is recognized by macrophages that engulf and degrade the affected cells. Eryptosis is triggered by erythrocyte injury after several stressors, including oxidative stress. Besides caspase activation after oxidative stress, two signaling pathways converge to trigger eryptosis: (a) formation of prostaglandin E(2) leads to activation of Ca(2+)-permeable cation channels, and (b) the phospholipase A(2)-mediated release of platelet-activating factor activates a sphingomyelinase, leading to formation of ceramide. Increased cytosolic Ca(2+) activity and enhanced ceramide levels lead to membrane scrambling with subsequent phosphatidylserine exposure. Moreover, Ca(2+) activates Ca(2+)-sensitive K(2+) channels, leading to cellular KCl loss and cell shrinkage. In addition, Ca(2+) stimulates the protease calpain, resulting in degradation of the cytoskeleton. Eryptosis is inhibited by erythropoietin, which thus extends the life span of circulating erythrocytes. Eryptosis may be a mechanism of defective erythrocytes to escape hemolysis. Conversely, excessive eryptosis favors the development of anemia. Conditions with excessive eryptosis include iron deficiency, lead or mercury intoxication, sickle cell anemia, thalassemia, glucose 6- phosphate dehydrogenase deficiency, malaria, and infection with hemolysin-forming pathogens.
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Affiliation(s)
- Florian Lang
- Department of Physiology, Eberhard-Karls-University of Tübingen, Germany.
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31
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Klarl BA, Lang PA, Kempe DS, Niemoeller OM, Akel A, Sobiesiak M, Eisele K, Podolski M, Huber SM, Wieder T, Lang F. Protein kinase C mediates erythrocyte "programmed cell death" following glucose depletion. Am J Physiol Cell Physiol 2006; 290:C244-53. [PMID: 16338977 DOI: 10.1152/ajpcell.00283.2005] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucose depletion of erythrocytes leads to activation of Ca2+-permeable cation channels, Ca2+ entry, activation of a Ca2+-sensitive erythrocyte scramblase, and subsequent exposure of phosphatidylserine at the erythrocyte surface. Ca2+ entry into erythrocytes was previously shown to be stimulated by phorbol esters and to be inhibited by staurosporine and chelerythrine and is thus thought to be regulated by protein phosphorylation/dephosphorylation, presumably via protein kinase C (PKC) and the corresponding phosphoserine/threonine phosphatases. The present experiments explored whether PKC could contribute to effects of energy depletion on erythrocyte phosphatidylserine exposure and cell volume. Phosphatidylserine exposure was estimated from annexin binding and cell volume from forward scatter in fluorescence-activated cell sorter analysis. Removal of extracellular glucose led to depletion of cellular ATP, stimulated PKC activity, led to translocation of PKCalpha, enhanced serine phosphorylation of membrane proteins, decreased cell volume, and increased annexin binding, the latter effect being blunted but not abolished in the presence of 1 microM staurosporine or 50 nM calphostin C. The PKC stimulator phorbol-12-myristate-13-acetate (3 microM) and the phosphatase inhibitor okadaic acid (1-10 microM) mimicked the effect of glucose depletion and similarly led to translocation of PKCalpha and enhanced serine phosphorylation, increased annexin binding, and decreased forward scatter, the latter effects being abrogated by PKC inhibitor staurosporine (1 microM). Fluo-3 fluorescence measurements revealed that okadaic acid also enhanced erythrocyte Ca2+ activity. The present observations suggest that protein phosphorylation and dephosphorylation via PKC and the corresponding protein phosphatases contribute to phosphatidylserine exposure and cell shrinkage after energy depletion.
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Affiliation(s)
- Barbara A Klarl
- Department of Physiology, University of Tübingen, Tübingen, Germany
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Sridhar J, Pattabiraman N. Synthesis and isozyme selectivity of small molecule protein kinase C inhibitors: a review of patents. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.15.12.1691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Piechulek T, Rehlen T, Walliser C, Vatter P, Moepps B, Gierschik P. Isozyme-specific stimulation of phospholipase C-gamma2 by Rac GTPases. J Biol Chem 2005; 280:38923-31. [PMID: 16172125 DOI: 10.1074/jbc.m509396200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The regulation of the two isoforms of phospholipase C-gamma, PLCgamma(1) and PLCgamma(2), by cell surface receptors involves protein tyrosine phosphorylation as well as interaction with adapter proteins and phosphatidylinositol 3,4,5-trisphosphate (PtdInsP(3)) generated by inositol phospholipid 3-kinases (PI3Ks). All three processes may lead to recruitment of the PLCgamma isozymes to the plasma membrane and/or stimulation of their catalytic activity. Recent evidence suggests that PLCgamma may also be regulated by Rho GTPases. In this study, PLCgamma(1) and PLCgamma(2) were reconstituted in intact cells and in a cell-free system with Rho GTPases to examine their influence on PLCgamma activity. PLCgamma(2), but not PLCgamma(1), was markedly activated in intact cells by constitutively active Rac1(G12V), Rac2(G12V), and Rac3(G12V) but not by Cdc42(G12V) and RhoA(G14V). The mechanism of PLCgamma(2) activation was apparently independent of phosphorylation of tyrosine residues known to be modified by PLCgamma(2)-activating protein-tyrosine kinases. Activation of PLCgamma(2) by Rac2(G12V) in intact cells coincided with a translocation of PLCgamma(2) from the soluble to the particulate fraction. PLCgamma isozyme-specific activation of PLCgamma(2) by Rac GTPases (Rac1 approximately Rac2 > Rac3), but not by Cdc42 or RhoA, was also observed in a cell-free system. Herein, activation of wild-type Rac GTPases with guanosine 5'-(3-O-thio)triphosphate caused a marked stimulation of PLCgamma(2) but had no effect on the activity of PLCgamma(1). PLCgamma(1) and PLCgamma(2) have previously been shown to be indiscriminately activated by PtdInsP(3) in vitro. Thus, the results suggest a novel mechanism of PLCgamma(2) activation by Rac GTPases involving neither protein tyrosine phosphorylation nor PI3K-mediated generation of PtdInsP(3).
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Affiliation(s)
- Thomas Piechulek
- Department of Pharmacology and Toxicology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Neschen S, Morino K, Hammond LE, Zhang D, Liu ZX, Romanelli AJ, Cline GW, Pongratz RL, Zhang XM, Choi CS, Coleman RA, Shulman GI. Prevention of hepatic steatosis and hepatic insulin resistance in mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase 1 knockout mice. Cell Metab 2005; 2:55-65. [PMID: 16054099 DOI: 10.1016/j.cmet.2005.06.006] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Revised: 05/10/2005] [Accepted: 06/22/2005] [Indexed: 10/25/2022]
Abstract
In order to investigate the role of mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase 1 (mtGPAT1) in the pathogenesis of hepatic steatosis and hepatic insulin resistance, we examined whole-body insulin action in awake mtGPAT1 knockout (mtGPAT1(-/-)) and wild-type (wt) mice after regular control diet or three weeks of high-fat feeding. In contrast to high-fat-fed wt mice, mtGPAT1(-/-) mice displayed markedly lower hepatic triacylglycerol and diacylglycerol concentrations and were protected from hepatic insulin resistance possibly due to a lower diacylglycerol-mediated PKC activation. Hepatic acyl-CoA has previously been implicated in the pathogenesis of insulin resistance. Surprisingly, compared to wt mice, mtGPAT1(-/-) mice exhibited increased hepatic insulin sensitivity despite an almost 2-fold elevation in hepatic acyl-CoA content. These data suggest that mtGPAT1 might serve as a novel target for treatment of hepatic steatosis and hepatic insulin resistance and that long chain acyl-CoA's do not mediate fat-induced hepatic insulin resistance in this model.
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Affiliation(s)
- Susanne Neschen
- Howard Hughes Medical Institute, Department of Internal Medicine, Yale University School of Medicine, New Haven, CN 06520, USA
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Orchel A, Dzierzewicz Z, Parfiniewicz B, Weglarz L, Wilczok T. Butyrate-induced differentiation of colon cancer cells is PKC and JNK dependent. Dig Dis Sci 2005; 50:490-8. [PMID: 15810631 DOI: 10.1007/s10620-005-2463-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Butyric acid, a short-chain fatty acid physiologically present in human large gut, is derived from bacterial fermentation of complex carbohydrates. It has been shown to reduce the growth and motility of colon cancer cell lines and to induce cell differentiation and apoptosis. Apoptosis is considered a result of normal colonocyte terminal differentiation in vivo. The aim of this study was to characterize the cellular mechanisms regulating differentiation of colon cancer cells stimulated with sodium butyrate (NaB). The two human colon cancer cell lines Caco-2 and HT-29 were treated with NaB at physiologically relevant concentrations. Alkaline phosphatase (ALP) activity, a marker of colonocyte differentiation, was increased 48 hr after treatment with 1 mM NaB. Higher doses of NaB (5 and 10 mM) induced apoptosis of the cells and failed to stimulate the colonocyte differentiation. Therefore, we assumed that butyrate augments cell differentiation and induces apoptosis, acting via various intracellular mechanisms, and butyrate-mediated programmed cell death cannot be considered a consequence of colonocyte terminal differentiation. The effect of NaB on ALP activity was significantly attenuated in the presence of inhibitors of protein kinase C and JNK. Inhibition of MEK-ERK signal transduction pathways augmented the impact of butyrate on colonocyte differentiation. These results suggest that butyrate could influence the colonocyte differentiation via modulation of the activity of cellular protein kinases and signal transduction.
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Affiliation(s)
- Arkadiusz Orchel
- Department of Biopharmacy, Medical University of Silesia, 41-200 Sosnowiec, Poland.
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Spitaler M, Cantrell DA. Protein kinase C and beyond. Nat Immunol 2004; 5:785-90. [PMID: 15282562 DOI: 10.1038/ni1097] [Citation(s) in RCA: 222] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Accepted: 06/07/2004] [Indexed: 11/08/2022]
Abstract
Protein kinase C molecules regulate both positive and negative signal transduction pathways essential for the initiation and homeostasis of immune responses. There are multiple isoforms of protein kinase C that are activated differently by calcium and diacylglycerol, and these are activated mainly by antigen receptors in T cells, B cells and mast cells. Additionally, mammals express several other diacylglycerol binding proteins that are linked to a network of key signal transduction pathways that control lymphocyte biology. Diacylglycerol and protein kinase C regulate a broad range of gene transcription programs but also modulate integrins, chemokine responses and antigen receptors, thereby regulating lymphocyte adhesion, migration, differentiation and proliferation.
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Affiliation(s)
- Martin Spitaler
- School of Life Sciences, Division of Cell Biology & Immunology, University of Dundee, MSI/WTB Complex, Dow Street, Dundee DD1 5EH, UK
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