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Hibberd TJ, Costa M, Smolilo DJ, Keightley LJ, Brookes SJ, Dinning PG, Spencer NJ. Mechanisms underlying initiation of propulsion in guinea pig distal colon. Am J Physiol Gastrointest Liver Physiol 2022; 323:G71-G87. [PMID: 35502864 DOI: 10.1152/ajpgi.00055.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Colonic motor complexes (CMCs) are a major neurogenic activity in guineapig distal colon. The identity of the enteric neurons that initiate this activity is not established. Specialized intrinsic primary afferent neurons (IPANs) are a major candidate. We aimed to test this hypothesis. To do this, segments of guineapig distal colon were suspended vertically in heated organ baths and propulsive forces acting on a pellet inside the lumen were recorded by isometric force transducer while pharmacological agents were applied to affect IPAN function. In the absence of drugs, CMCs acted periodically on the pellet, generating peak propulsive forces of 12.7 ± 5 g at 0.56 ± 0.22 cpm, lasting 49 ± 17 s (215 preparations; n = 60). Most but not all CMCs were abolished by nicotinic receptor blockade to inhibit fast excitatory synaptic transmission (50/62 preparations; n = 25). Remarkably, CMCs inhibited by hexamethonium were restored by a pharmacological strategy that aimed to enhance IPAN excitability. Thus, CMCs were restored by increased smooth muscle tension (using BAY K8644, bethanechol or carbachol) and by IPAN excitation using phorbol dibutyrate; NK3 receptor agonist, senktide; and partially by αCGRP. The IPAN inhibitor, 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazole-2-one (DCEBIO), decreased CMC frequency. CGRP, but not NK3-receptor antagonists, decreased CMC frequency in naive preparations. Finally, CMCs were blocked by tetrodotoxin, and this was not reversed by any drugs listed above. These results support a major role for IPANs that does not require fast synaptic transmission, in the periodic initiation of neurogenic propulsive contractions. Endogenous CGRP plays a role in determining CMC frequency, whereas further unidentified signaling pathways may determine their amplitude and duration.NEW & NOTEWORTHY The colonic motor complex (CMC) initiates propulsion in guinea pig colon. Here, CMCs evoked by an intraluminal pellet were restored during nicotinic receptor blockade by pharmacological agents that directly or indirectly enhance intrinsic primary afferent neuron (IPAN) excitability. IPANs are the only enteric neuron in colon that contain CGRP. Blocking CGRP receptors decreased CMC frequency, implicating their role in CMC initiation. The results support a role for IPANs in the initiation of CMCs.
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Affiliation(s)
- Timothy J Hibberd
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Marcello Costa
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - David J Smolilo
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Lauren J Keightley
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Simon J Brookes
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Phil G Dinning
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Nick J Spencer
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
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2
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Oskoueian E, Oskoueian A, Shakeri M, Jahromi MF. Benefits and Challenges of Jatropha Meal as Novel Biofeed for Animal Production. Vet Sci 2021; 8:179. [PMID: 34564573 PMCID: PMC8472097 DOI: 10.3390/vetsci8090179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/28/2021] [Accepted: 08/30/2021] [Indexed: 11/30/2022] Open
Abstract
Jatropha curcas L. has gained importance as a source of seed oil for biodiesel production. The meal contained about 60% protein with a good balance of essential amino acids, containing various bioactive compounds, including saponins, phytic acids, trypsin inhibitors, lectins, phenolics, and flavonoids, which render it as a potential biofeed for animal production. The Jatropha meal demonstrated various biological activities, including antioxidant, antibacterial, and anti-inflammatory effects which enhance its property as a bio-feed. The levels of these bioactive compounds in the seeds are dependent on the genotypes. The J. curcas possessed different varieties which are either toxic or non-toxic according to the presence of phorbol esters. The presence of phorbol esters in the meal confirmed the toxic variety of Jatropha resulting in the limited application of meal as a biofeed. The Jatropha meal devoid of phorbol esters could be applied as a biofeed in the animal production industry, and for the toxic varieties, various techniques such as physicochemical and biological treatments have been introduced to the industry to remove the phorbol esters from Jatropha meal. Several studies employing various cells and animals confirmed the toxicity of the phorbol esters. The molecular mechanism of action of phorbol esters is through up-regulation of PKC-β II gene, overexpression of down-stream proto-oncogenes resulted in inflammation and oxidative stress ending by apoptotic cell death. Despite the presence of valuable bioactive compounds in the Jatropha meal, its nutritional application is not recommended unless the phorbol esters are completely removed.
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Affiliation(s)
- Ehsan Oskoueian
- Department of Research and Development, Arka Biotechnology Corporation, Mashhad 1696700, Iran; (A.O.); (M.F.J.)
| | - Arshin Oskoueian
- Department of Research and Development, Arka Biotechnology Corporation, Mashhad 1696700, Iran; (A.O.); (M.F.J.)
| | - Majid Shakeri
- Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Mohammad Faseleh Jahromi
- Department of Research and Development, Arka Biotechnology Corporation, Mashhad 1696700, Iran; (A.O.); (M.F.J.)
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3
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DGKα in Neutrophil Biology and Its Implications for Respiratory Diseases. Int J Mol Sci 2019; 20:ijms20225673. [PMID: 31766109 PMCID: PMC6887790 DOI: 10.3390/ijms20225673] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 12/21/2022] Open
Abstract
Diacylglycerol kinases (DGKs) play a key role in phosphoinositide signaling by removing diacylglycerol and generating phosphatidic acid. Besides the well-documented role of DGKα and DGKζ as negative regulators of lymphocyte responses, a robust body of literature points to those enzymes, and specifically DGKα, as crucial regulators of leukocyte function. Upon neutrophil stimulation, DGKα activation is necessary for migration and a productive response. The role of DGKα in neutrophils is evidenced by its aberrant behavior in juvenile periodontitis patients, which express an inactive DGKα transcript. Together with in vitro experiments, this suggests that DGKs may represent potential therapeutic targets for disorders where inflammation, and neutrophils in particular, plays a major role. In this paper we focus on obstructive respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD), but also rare genetic diseases such as alpha-1-antitrypsin deficiency. Indeed, the biological role of DGKα is understudied outside the T lymphocyte field. The recent wave of research aiming to develop novel and specific inhibitors as well as KO mice will allow a better understanding of DGK's role in neutrophilic inflammation. Better knowledge and pharmacologic tools may also allow DGK to move from the laboratory bench to clinical trials.
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4
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Diacylglycerol kinase control of protein kinase C. Biochem J 2019; 476:1205-1219. [DOI: 10.1042/bcj20180620] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 12/27/2022]
Abstract
Abstract
The diacylglycerol kinases (DGK) are lipid kinases that transform diacylglycerol (DAG) into phosphatidic acid (PA) in a reaction that terminates DAG-based signals. DGK provide negative regulation to conventional and novel protein kinase C (PKC) enzymes, limiting local DAG availability in a tissue- and subcellular-restricted manner. Defects in the expression/activity of certain DGK isoforms contribute substantially to cognitive impairment and mental disorders. Abnormal DGK overexpression in tumors facilitates invasion and resistance to chemotherapy preventing tumor immune destruction by tumor-infiltrating lymphocytes. Effective translation of these findings into therapeutic approaches demands a better knowledge of the physical and functional interactions between the DGK and PKC families. DGKζ is abundantly expressed in the nervous and immune system, where physically and functionally interacts with PKCα. The latest discoveries suggest that PDZ-mediated interaction facilitates spatial restriction of PKCα by DGKζ at the cell–cell contact sites in a mechanism where the two enzymes regulate each other. In T lymphocytes, DGKζ interaction with Sorting Nexin 27 (SNX27) guarantees the basal control of PKCα activation. SNX27 is a trafficking component required for normal brain function whose deficit has been linked to Alzheimer's disease (AD) pathogenesis. The enhanced PKCα activation as the result of SNX27 silencing in T lymphocytes aligns with the recent correlation found between gain-of-function PKCα mutations and AD and suggests that disruption of the mechanisms that provides a correct spatial organization of DGKζ and PKCα may lie at the basis of immune and neuronal synapse impairment.
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5
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Oskoueian E, Abdullah N, Noura R, Ebrahimi M, Ahmad S, Shakeri M. Mode of action of Jatropha curcas phorbol esters in bovine kidney cells. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2019. [DOI: 10.1016/j.bcab.2019.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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PKC delta activation increases neonatal rat retinal cells survival in vitro: Involvement of neurotrophins and M1 muscarinic receptors. Biochem Biophys Res Commun 2018; 500:917-923. [PMID: 29705702 DOI: 10.1016/j.bbrc.2018.04.193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 04/24/2018] [Indexed: 01/02/2023]
Abstract
Protein kinase C (PKC) is a family of serine/threonine kinases related to several phenomena as cell proliferation, differentiation and survival. Our previous data demonstrated that treatment of axotomized neonatal rat retinal cell cultures for 48 h with phorbol 12-myristate 13-acetate (PMA), a PKC activator, increases retinal ganglion cells (RGCs) survival. Moreover, this treatment decreases M1 receptors (M1R) and modulates BDNF levels. The aim of this work was to assess the possible involvement of neurotrophins BDNF and NGF in the modulation of M1R levels induced by PKC activation, and its involvement on RGCs survival. Our results show that PMA (50 ng/mL) treatment, via PKC delta activation, modulates NGF, BDNF and M1R levels. BDNF and NGF mediate the decrease of M1R levels induced by PMA treatment. M1R activation is essential to PMA neuroprotective effect on RGCs as telenzepine (M1R selective antagonist) abolished it. Based on our results we suggest that PKC delta activation modulates neurotrophins levels by a signaling pathway that involves M1R activation and ultimately leading to an increase in RGCs survival in vitro.
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7
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Czikora A, Kedei N, Kalish H, Blumberg PM. Importance of the REM (Ras exchange) domain for membrane interactions by RasGRP3. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2017; 1859:2350-2360. [PMID: 28912101 PMCID: PMC5659902 DOI: 10.1016/j.bbamem.2017.09.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 11/18/2022]
Abstract
RasGRP comprises a family of guanine nucleotide exchange factors, regulating the dissociation of GDP from Ras GTPases to enhance the formation of the active GTP-bound form. RasGRP1 possesses REM (Ras exchange), GEF (catalytic), EF-hand, C1, SuPT (suppressor of PT), and PT (plasma membrane-targeting) domains, among which the C1 domain drives membrane localization in response to diacylglycerol or phorbol ester and the PT domain recognizes phosphoinositides. The homologous family member RasGRP3 shows less plasma membrane localization. The objective of this study was to explore the role of the different domains of RasGRP3 in membrane translocation in response to phorbol esters. The full-length RasGRP3 shows limited translocation to the plasma membrane in response to PMA, even when the basic hydrophobic cluster in the PT domain, reported to be critical for RasGRP1 translocation to endogenous activators, is mutated to resemble that of RasGRP1. Moreover, exchange of the C-termini (SuPT-PT domain) of the two proteins had little effect on their plasma membrane translocation. On the other hand, while the C1 domain of RasGRP3 alone showed partial plasma membrane translocation, truncated RasGRP3 constructs, which contain the PT domain and are missing the REM, showed stronger translocation, indicating that the REM of RasGRP3 was a suppressor of its membrane interaction. The REM of RasGRP1 failed to show comparable suppression of RasGRP3 translocation. The marked differences between RasGRP3 and RasGRP1 in membrane interaction necessarily will contribute to their different behavior in cells and are relevant to the design of selective ligands as potential therapeutic agents.
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Affiliation(s)
- Agnes Czikora
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Noemi Kedei
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States
| | - Heather Kalish
- Trans-NIH Shared Resource on Biomedical Engineering and Physical Science (BEPS), National Institute of Biomedical Imaging and Bioengineering (NIBIB) National Institutes of Health, United States
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, United States.
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8
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Leroux AE, Schulze JO, Biondi RM. AGC kinases, mechanisms of regulation and innovative drug development. Semin Cancer Biol 2017; 48:1-17. [PMID: 28591657 DOI: 10.1016/j.semcancer.2017.05.011] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/16/2017] [Accepted: 05/31/2017] [Indexed: 12/22/2022]
Abstract
The group of AGC kinases consists of 63 evolutionarily related serine/threonine protein kinases comprising PDK1, PKB/Akt, SGK, PKC, PRK/PKN, MSK, RSK, S6K, PKA, PKG, DMPK, MRCK, ROCK, NDR, LATS, CRIK, MAST, GRK, Sgk494, and YANK, while two other families, Aurora and PLK, are the most closely related to the group. Eight of these families are physiologically activated downstream of growth factor signalling, while other AGC kinases are downstream effectors of a wide range of signals. The different AGC kinase families share aspects of their mechanisms of inhibition and activation. In the present review, we update the knowledge of the mechanisms of regulation of different AGC kinases. The conformation of the catalytic domain of many AGC kinases is regulated allosterically through the modulation of the conformation of a regulatory site on the small lobe of the kinase domain, the PIF-pocket. The PIF-pocket acts like an ON-OFF switch in AGC kinases with different modes of regulation, i.e. PDK1, PKB/Akt, LATS and Aurora kinases. In this review, we make emphasis on how the knowledge of the molecular mechanisms of regulation can guide the discovery and development of small allosteric modulators. Molecular probes stabilizing the PIF-pocket in the active conformation are activators, while compounds stabilizing the disrupted site are allosteric inhibitors. One challenge for the rational development of allosteric modulators is the lack of complete structural information of the inhibited forms of full-length AGC kinases. On the other hand, we suggest that the available information derived from molecular biology and biochemical studies can already guide screening strategies for the identification of innovative mode of action molecular probes and the development of selective allosteric drugs for the treatment of human diseases.
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Affiliation(s)
- Alejandro E Leroux
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina.
| | - Jörg O Schulze
- Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Ricardo M Biondi
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina; Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany, German Cancer Research Center (DKFZ), Heidelberg, Germany.
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9
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Hautala LC, Koistinen R, Koistinen H. Repressed PKCδ activation in glycodelin-expressing cells mediates resistance to phorbol ester and TGFβ. Cell Signal 2016; 28:1463-9. [PMID: 27373413 DOI: 10.1016/j.cellsig.2016.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 06/17/2016] [Accepted: 06/27/2016] [Indexed: 11/30/2022]
Abstract
Glycodelin is a glycoprotein mainly expressed in well-differentiated epithelial cells in reproductive tissues. In normal secretory endometrium, the expression of glycodelin is abundant and regulated by progesterone. In hormone-related cancers glycodelin expression is associated with well-differentiated tumors. We have previously found that glycodelin drives epithelial differentiation of HEC-1B endometrial adenocarcinoma cells, resulting in reduced tumor growth in a preclinical mouse model. Here we show that glycodelin-transfected HEC-1B cells have repressed protein kinase C delta (PKCδ) activation, likely due to downregulation of PDK1, and are resistant to phenotypic change and enhanced migration induced by phorbol 12-myristate 13-acetate (PMA). In control cells, which do not express glycodelin, the effects of PMA were abolished by using PKCδ and PDK1 inhibitors, and knockdown of PKCδ, MEK1 and 2, or ERK1 and 2 by siRNAs. Similarly, transforming growth factor β (TGFβ)-induced phenotypic change was only seen in control cells, not in glycodelin-producing cells, and it was mediated by PKCδ. Taken together, these results strongly suggest that PKCδ, via MAPK pathway, is involved in the glycodelin-driven cell differentiation rendering the cells resistant to stimulation by PMA and TGFβ.
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Affiliation(s)
- Laura C Hautala
- Department of Clinical Chemistry, Medicum, University of Helsinki and Helsinki University Central Hospital, Haartmaninkatu 8, 00290 Helsinki, Finland
| | - Riitta Koistinen
- Department of Clinical Chemistry, Medicum, University of Helsinki and Helsinki University Central Hospital, Haartmaninkatu 8, 00290 Helsinki, Finland
| | - Hannu Koistinen
- Department of Clinical Chemistry, Medicum, University of Helsinki and Helsinki University Central Hospital, Haartmaninkatu 8, 00290 Helsinki, Finland.
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10
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Hormetic and regulatory effects of lipid peroxidation mediators in pancreatic beta cells. Mol Aspects Med 2016; 49:49-77. [PMID: 27012748 DOI: 10.1016/j.mam.2016.03.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 02/23/2016] [Accepted: 03/09/2016] [Indexed: 12/12/2022]
Abstract
Nutrient sensing mechanisms of carbohydrates, amino acids and lipids operate distinct pathways that are essential for the adaptation to varying metabolic conditions. The role of nutrient-induced biosynthesis of hormones is paramount for attaining metabolic homeostasis in the organism. Nutrient overload attenuate key metabolic cellular functions and interfere with hormonal-regulated inter- and intra-organ communication, which may ultimately lead to metabolic derangements. Hyperglycemia and high levels of saturated free fatty acids induce excessive production of oxygen free radicals in tissues and cells. This phenomenon, which is accentuated in both type-1 and type-2 diabetic patients, has been associated with the development of impaired glucose tolerance and the etiology of peripheral complications. However, low levels of the same free radicals also induce hormetic responses that protect cells against deleterious effects of the same radicals. Of interest is the role of hydroxyl radicals in initiating peroxidation of polyunsaturated fatty acids (PUFA) and generation of α,β-unsaturated reactive 4-hydroxyalkenals that avidly form covalent adducts with nucleophilic moieties in proteins, phospholipids and nucleic acids. Numerous studies have linked the lipid peroxidation product 4-hydroxy-2E-nonenal (4-HNE) to different pathological and cytotoxic processes. Similarly, two other members of the family, 4-hydroxyl-2E-hexenal (4-HHE) and 4-hydroxy-2E,6Z-dodecadienal (4-HDDE), have also been identified as potential cytotoxic agents. It has been suggested that 4-HNE-induced modifications in macromolecules in cells may alter their cellular functions and modify signaling properties. Yet, it has also been acknowledged that these bioactive aldehydes also function as signaling molecules that directly modify cell functions in a hormetic fashion to enable cells adapt to various stressful stimuli. Recent studies have shown that 4-HNE and 4-HDDE, which activate peroxisome proliferator-activated receptor δ (PPARδ) in vascular endothelial cells and insulin secreting beta cells, promote such adaptive responses to ameliorate detrimental effects of high glucose and diabetes-like conditions. In addition, due to the electrophilic nature of these reactive aldehydes they form covalent adducts with electronegative moieties in proteins, phosphatidylethanolamine and nucleotides. Normally these non-enzymatic modifications are maintained below the cytotoxic range due to efficient cellular neutralization processes of 4-hydroxyalkenals. The major neutralizing enzymes include fatty aldehyde dehydrogenase (FALDH), aldose reductase (AR) and alcohol dehydrogenase (ADH), which transform the aldehyde to the corresponding carboxylic acid or alcohols, respectively, or by biding to the thiol group in glutathione (GSH) by the action of glutathione-S-transferase (GST). This review describes the hormetic and cytotoxic roles of oxygen free radicals and 4-hydroxyalkenals in beta cells exposed to nutritional challenges and the cellular mechanisms they employ to maintain their level at functional range below the cytotoxic threshold.
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Görlach A, Dimova EY, Petry A, Martínez-Ruiz A, Hernansanz-Agustín P, Rolo AP, Palmeira CM, Kietzmann T. Reactive oxygen species, nutrition, hypoxia and diseases: Problems solved? Redox Biol 2015; 6:372-385. [PMID: 26339717 PMCID: PMC4565025 DOI: 10.1016/j.redox.2015.08.016] [Citation(s) in RCA: 241] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/21/2015] [Accepted: 08/25/2015] [Indexed: 02/06/2023] Open
Abstract
Within the last twenty years the view on reactive oxygen species (ROS) has changed; they are no longer only considered to be harmful but also necessary for cellular communication and homeostasis in different organisms ranging from bacteria to mammals. In the latter, ROS were shown to modulate diverse physiological processes including the regulation of growth factor signaling, the hypoxic response, inflammation and the immune response. During the last 60–100 years the life style, at least in the Western world, has changed enormously. This became obvious with an increase in caloric intake, decreased energy expenditure as well as the appearance of alcoholism and smoking; These changes were shown to contribute to generation of ROS which are, at least in part, associated with the occurrence of several chronic diseases like adiposity, atherosclerosis, type II diabetes, and cancer. In this review we discuss aspects and problems on the role of intracellular ROS formation and nutrition with the link to diseases and their problematic therapeutical issues. Oxidative stress is linked to overnutrition, obesity and associated diseases or cancer. Reactive oxygen species (ROS) are crucially involved in modulation of signaling cascades. NOX proteins and hypoxia contribute to formation of ROS under different nutrient regimes. ROS are powerful post-transcriptional and epigenetic regulators. Treatment of obesity with antioxidants requires more, larger, and better monitored clinical trials.
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Affiliation(s)
- Agnes Görlach
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich, Technical University Munich, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Elitsa Y Dimova
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Andreas Petry
- Experimental and Molecular Pediatric Cardiology, German Heart Center Munich, Technical University Munich, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Antonio Martínez-Ruiz
- Servicio de Immunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain
| | - Pablo Hernansanz-Agustín
- Servicio de Immunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa, Madrid, Spain; Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Anabela P Rolo
- Department of Life Sciences, University of Coimbra and Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - Carlos M Palmeira
- Department of Life Sciences, University of Coimbra and Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - Thomas Kietzmann
- Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland.
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12
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Pu Y, Kang JH, Sigano DM, Peach M, Lewin NE, Marquez VE, Blumberg PM. Diacylglycerol lactones targeting the structural features that distinguish the atypical C1 domains of protein kinase C ζ and ι from typical C1 domains. J Med Chem 2014; 57:3835-44. [PMID: 24684293 PMCID: PMC4310642 DOI: 10.1021/jm500165n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Indexed: 01/25/2023]
Abstract
To explore the feasibility of developing ligands targeted to the atypical C1 domains of protein kinase C ζ and ι, we have prepared diacylglycerol lactones substituted with hydrophilic groups on their side chains, which potentially could interact with the arginine residues that distinguish the atypical C1 domains of PKCζ and PKCι from typical C1 domains, and we have measured their binding to mutated versions of the C1b domain of PKCδ that incorporate one or more of these arginine residues. The most selective of the diacylglycerol lactones showed only a 10-fold reduction in binding affinity with the triple arginine mutant (N7R/S10R/L20R) compared to the wild-type, whereas phorbol 12,13-dibutyrate showed a 6000-fold loss of affinity. Molecular modeling confirms that these ligands are indeed able to interact with the arginine residues. Our results show that dramatic changes in selectivity can be obtained through appropriate substitution of diacylglycerol lactones.
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Affiliation(s)
- Yongmei Pu
- Laboratory
of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of
Health, Bethesda, Maryland 20892, United
States
| | - Ji-Hye Kang
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland 21702, United States
| | - Dina M. Sigano
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland 21702, United States
| | - Megan
L. Peach
- Chemical
Biology Laboratory, Basic Science Program, Frederick National Laboratory
for Cancer Research, Leidos Biomedical,
Inc., Frederick, Maryland 21702, United
States
| | - Nancy E. Lewin
- Laboratory
of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of
Health, Bethesda, Maryland 20892, United
States
| | - Victor E. Marquez
- Chemical
Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland 21702, United States
| | - Peter M. Blumberg
- Laboratory
of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of
Health, Bethesda, Maryland 20892, United
States
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13
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Kelsey JS, Geczy T, Lewin NE, Kedei N, Hill CS, Selezneva JS, Valle CJ, Woo W, Gorshkova I, Blumberg PM. Charge density influences C1 domain ligand affinity and membrane interactions. Chembiochem 2014; 15:1131-1144. [PMID: 24777910 DOI: 10.1002/cbic.201400041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Indexed: 12/25/2022]
Abstract
The C1 domain, which represents the recognition motif on protein kinase C for the lipophilic second messenger diacylglycerol and its ultrapotent analogues, the phorbol esters, has emerged as a promising therapeutic target for cancer and other indications. Potential target selectivity is markedly enhanced both because binding reflects ternary complex formation between the ligand, C1 domain, and phospholipid, and because binding drives membrane insertion of the C1 domain, permitting aspects of the C1 domain surface outside the binding site, per se, to influence binding energetics. Here, focusing on charged residues identified in atypical C1 domains which contribute to their loss of ligand binding activity, we showed that increasing charge along the rim of the binding cleft of the protein kinase C δ C1 b domain raises the requirement for anionic phospholipids. Correspondingly, it shifts the selectivity of C1 domain translocation to the plasma membrane, which is more negatively charged than internal membranes. This change in localization is most pronounced in the case of more hydrophilic ligands, which provide weaker membrane stabilization than do the more hydrophobic ligands and thus contributes an element to the structure-activity relations for C1 domain ligands. Coexpressing pairs of C1-containing constructs with differing charges each expressing a distinct fluorescent tag provided a powerful tool to demonstrate the effect of increasing charge in the C1 domain.
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Affiliation(s)
- Jessica S Kelsey
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Tamas Geczy
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Nancy E Lewin
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Noemi Kedei
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Colin S Hill
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Julia S Selezneva
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Christopher J Valle
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Wonhee Woo
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
| | - Inna Gorshkova
- Biomedical Engineering and Physical Science Share Resource Program, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, U.S.A
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, U.S.A
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14
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Samoylenko A, Hossain JA, Mennerich D, Kellokumpu S, Hiltunen JK, Kietzmann T. Nutritional countermeasures targeting reactive oxygen species in cancer: from mechanisms to biomarkers and clinical evidence. Antioxid Redox Signal 2013; 19:2157-96. [PMID: 23458328 PMCID: PMC3869543 DOI: 10.1089/ars.2012.4662] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 02/08/2013] [Accepted: 03/01/2013] [Indexed: 02/06/2023]
Abstract
Reactive oxygen species (ROS) exert various biological effects and contribute to signaling events during physiological and pathological processes. Enhanced levels of ROS are highly associated with different tumors, a Western lifestyle, and a nutritional regime. The supplementation of food with traditional antioxidants was shown to be protective against cancer in a number of studies both in vitro and in vivo. However, recent large-scale human trials in well-nourished populations did not confirm the beneficial role of antioxidants in cancer, whereas there is a well-established connection between longevity of several human populations and increased amount of antioxidants in their diets. Although our knowledge about ROS generators, ROS scavengers, and ROS signaling has improved, the knowledge about the direct link between nutrition, ROS levels, and cancer is limited. These limitations are partly due to lack of standardized reliable ROS measurement methods, easily usable biomarkers, knowledge of ROS action in cellular compartments, and individual genetic predispositions. The current review summarizes ROS formation due to nutrition with respect to macronutrients and antioxidant micronutrients in the context of cancer and discusses signaling mechanisms, used biomarkers, and its limitations along with large-scale human trials.
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Affiliation(s)
- Anatoly Samoylenko
- Department of Biochemistry, Biocenter Oulu, University of Oulu, Oulu, Finland
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Jubayer Al Hossain
- Department of Biochemistry, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Daniela Mennerich
- Department of Biochemistry, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Sakari Kellokumpu
- Department of Biochemistry, Biocenter Oulu, University of Oulu, Oulu, Finland
| | | | - Thomas Kietzmann
- Department of Biochemistry, Biocenter Oulu, University of Oulu, Oulu, Finland
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15
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Song X, Lopez-Campistrous A, Sun L, Dower NA, Kedei N, Yang J, Kelsey JS, Lewin NE, Esch TE, Blumberg PM, Stone JC. RasGRPs are targets of the anti-cancer agent ingenol-3-angelate. PLoS One 2013; 8:e72331. [PMID: 23991094 PMCID: PMC3749120 DOI: 10.1371/journal.pone.0072331] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 07/08/2013] [Indexed: 11/26/2022] Open
Abstract
Ingenol-3–angelate (I3A) is a non-tumor promoting phorbol ester-like compound identified in the sap of Euphoria peplus. Similar to tumor promoting phorbol esters, I3A is a diacylglycerol (DAG) analogue that binds with high affinity to the C1 domains of PKCs, recruits PKCs to cellular membranes and promotes enzyme activation. Numerous anti-cancer activities have been attributed to I3A and ascribed to I3A’s effects on PKCs. We show here that I3A also binds to and activates members of the RasGRP family of Ras activators leading to robust elevation of Ras-GTP and engagement of the Raf-Mek-Erk kinase cascade. In response to I3A, recombinant proteins consisting of GFP fused separately to full-length RasGRP1 and RasGRP3 were rapidly recruited to cell membranes, consistent with direct binding of the compound to RasGRP’s C1 domain. In the case of RasGRP3, IA3 treatment led to positive regulatory phosphorylation on T133 and activation of the candidate regulatory kinase PKCδ. I3A treatment of select B non-Hodgkin’s lymphoma cell lines resulted in quantitative and qualitative changes in Bcl-2 family member proteins and induction of apoptosis, as previously demonstrated with the DAG analogue bryostatin 1 and its synthetic analogue pico. Our results offer further insights into the anticancer properties of I3A, support the idea that RasGRPs represent potential cancer therapeutic targets along with PKC, and expand the known range of ligands for RasGRP regulation.
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Affiliation(s)
- Xiaohua Song
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Lucy Sun
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nancy A. Dower
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Noemi Kedei
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jing Yang
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jessica S. Kelsey
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nancy E. Lewin
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tim E. Esch
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter M. Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - James C. Stone
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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Oskoueian E, Abdullah N, Ahmad S. Phorbol esters isolated from Jatropha meal induced apoptosis-mediated inhibition in proliferation of chang and Vero cell lines. Int J Mol Sci 2012. [PMID: 23203036 PMCID: PMC3509552 DOI: 10.3390/ijms131113816] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The direct feeding of Jatropha meal containing phorbol esters (PEs) indicated mild to severe toxicity symptoms in various organs of different animals. However, limited information is available on cellular and molecular mechanism of toxicity caused by PEs present in Jatropha meal. Thus, the present study was conducted to determine the cytotoxic and mode of action of PEs isolated from Jatropha meal using human hepatocyte (Chang) and African green monkey kidney (Vero) cell lines. The results showed that isolated PEs inhibited cell proliferation in a dose-dependent manner in both cell lines with the CC50 of 125.9 and 110.3 μg/mL, respectively. These values were compatible to that of phorbol 12-myristate 13-acetate (PMA) values as positive control i.e., 124.5 and 106.3 μg/mL respectively. Microscopic examination, flow cytometry and DNA fragmentation results confirmed cell death due to apoptosis upon treatment with PEs and PMA at CC50 concentration for 24 h in both cell lines. The Western blot analysis revealed the overexpression of PKC-Δ and activation of caspase-3 proteins which could be involved in the mechanism of action of PEs and PMA. Consequently, the PEs isolated form Jatropha meal caused toxicity and induced apoptosis-mediated proliferation inhibition toward Chang and Vero cell lines involving over-expression of PKC-Δ and caspase-3 as their mode of actions.
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Affiliation(s)
- Ehsan Oskoueian
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; E-Mail:
- Agriculture Biotechnology Research Institute of Iran (ABRII)-East and North-East Branch, P.O.B. 91735/844, Mashhad, Iran
| | - Norhani Abdullah
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; E-Mail:
- Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +603-89466700; Fax: +603-89430913
| | - Syahida Ahmad
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; E-Mail:
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17
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Oskoueian E, Abdullah N, Ahmad S. Phorbol esters from Jatropha meal triggered apoptosis, activated PKC-δ, caspase-3 proteins and down-regulated the proto-oncogenes in MCF-7 and HeLa cancer cell lines. Molecules 2012; 17:10816-30. [PMID: 22964499 PMCID: PMC6268826 DOI: 10.3390/molecules170910816] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/02/2012] [Accepted: 08/21/2012] [Indexed: 01/31/2023] Open
Abstract
Jatropha meal produced from the kernel of Jatropha curcas Linn. grown in Malaysia contains phorbol esters (PEs). The potential benefits of PEs present in the meal as anticancer agent are still not well understood. Hence, this study was conducted to evaluate the cytotoxic effects and mode of actions of PEs isolated from Jatropha meal against breast (MCF-7) and cervical (HeLa) cancer cell lines. Isolated PEs inhibited cells proliferation in a dose-dependent manner of both MCF-7 and HeLa cell lines with the IC₅₀ of 128.6 ± 2.51 and 133.0 ± 1.96 µg PMA equivalents/mL respectively, while the values for the phorbol 12-myristate 13-acetate (PMA) as positive control were 114.7 ± 1.73 and 119.6 ± 3.73 µg/mL, respectively. Microscopic examination showed significant morphological changes that resemble apoptosis in both cell lines when treated with PEs and PMA at IC₅₀ concentration after 24 h. Flow cytometry analysis and DNA fragmentation results confirmed the apoptosis induction of PEs and PMA in both cell lines. The PEs isolated from Jatropha meal activated the PKC-δ and down-regulated the proto-oncogenes (c-Myc, c-Fos and c-Jun). These changes probably led to the activation of Caspase-3 protein and apoptosis cell death occurred in MCF-7 and HeLa cell lines upon 24 h treatment with PEs and PMA. Phorbol esters of Jatropha meal were found to be promising as an alternative to replace the chemotherapeutic drugs for cancer therapy.
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Affiliation(s)
- Ehsan Oskoueian
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
- Agriculture Biotechnology Research Institute of Iran (ABRII)-East and North-East Branch, Mashhad 91735, Iran
| | - Norhani Abdullah
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
- Institute of Tropical Agriculture, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - Syahida Ahmad
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
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18
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Chowdhury RR, Ghosh SK. Phytol-derived novel isoprenoid immunostimulants. Front Immunol 2012; 3:49. [PMID: 22566931 PMCID: PMC3342073 DOI: 10.3389/fimmu.2012.00049] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 02/28/2012] [Indexed: 12/03/2022] Open
Abstract
This review describes the adjuvanticity of novel diterpenoids (synthetic phytol derivatives) compared to some commercially available adjuvants. The efficacy of the phytol-derived immunostimulants was evaluated in terms of their ability to activate innate immunity, amplify various antigen-specific immune responses, and engender immunological memory with no discernible adverse effects in both competent and immune-deficient mice. The profile that emerges out of these studies reveals that the phytol derivatives are excellent immunostimulants, superior to a number of commercial adjuvants in terms of long-term memory induction and activation of both innate and acquired immunity. Additionally, the phytol-derived compounds have no cumulative inflammatory or toxic effects even in immuno-compromised mice.
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19
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C1 Domain-targeted isophthalate derivatives induce cell elongation and cell cycle arrest in HeLa cells. PLoS One 2011; 6:e20053. [PMID: 21629792 PMCID: PMC3100349 DOI: 10.1371/journal.pone.0020053] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/11/2011] [Indexed: 11/19/2022] Open
Abstract
Diacylglycerol (DAG)-mediated signaling pathways, such as those mediated by protein kinase C (PKC), are central in regulating cell proliferation and apoptosis. DAG-responsive C1 domains are therefore considered attractive drug targets. Our group has designed a novel class of compounds targeted to the DAG binding site within the C1 domain of PKC. We have previously shown that these 5-(hydroxymethyl)isophthalates modulate PKC activation in living cells. In this study we investigated their effects on HeLa human cervical cancer cell viability and proliferation by using standard cytotoxicity tests and an automated imaging platform with machine vision technology. Cellular effects and their mechanisms were further characterized with the most potent compound, HMI-1a3. Isophthalate derivatives with high affinity to the PKC C1 domain exhibited antiproliferative and non-necrotic cytotoxic effects on HeLa cells. The anti-proliferative effect was irreversible and accompanied by cell elongation. HMI-1a3 induced down-regulation of retinoblastoma protein and cyclins A, B1, D1, and E. Effects of isophthalates on cell morphology, cell proliferation and expression of cell cycle-related proteins were different from those induced by phorbol 12-myristate-13-acetate (PMA) or bryostatin 1, but correlated closely to binding affinities. Therefore, the results strongly indicate that the effect is C1 domain-mediated.
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20
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Stewart MD, Morgan B, Massi F, Igumenova TI. Probing the determinants of diacylglycerol binding affinity in the C1B domain of protein kinase Cα. J Mol Biol 2011; 408:949-70. [PMID: 21419781 DOI: 10.1016/j.jmb.2011.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/09/2011] [Accepted: 03/10/2011] [Indexed: 01/20/2023]
Abstract
C1 domains are independently folded modules that are responsible for targeting their parent proteins to lipid membranes containing diacylglycerol (DAG), a ubiquitous second messenger. The DAG binding affinities of C1 domains determine the threshold concentration of DAG required for the propagation of signaling response and the selectivity of this response among DAG receptors in the cell. The structural information currently available for C1 domains offers little insight into the molecular basis of their differential DAG binding affinities. In this work, we characterized the C1B domain of protein kinase Cα (C1Bα) and its diagnostic mutant, Y123W, using solution NMR methods and molecular dynamics simulations. The mutation did not perturb the C1Bα structure or the sub-nanosecond dynamics of the protein backbone, but resulted in a >100-fold increase in DAG binding affinity and a substantial change in microsecond timescale conformational dynamics, as quantified by NMR rotating-frame relaxation-dispersion methods. The differences in the conformational exchange behavior between wild type and Y123W C1Bα were localized to the hinge regions of ligand-binding loops. Molecular dynamics simulations provided insight into the identity of the exchanging conformers and revealed the significance of a particular residue (Gln128) in modulating the geometry of the ligand-binding site. Taken together with the results of binding studies, our findings suggest that the conformational dynamics and preferential partitioning of the tryptophan side chain into the water-lipid interface are important factors that modulate the DAG binding properties of the C1 domains.
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Affiliation(s)
- Mikaela D Stewart
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX 77843, USA
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21
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TLR2-dependent pathway of heterologous down-modulation for the CC chemokine receptors 1, 2, and 5 in human blood monocytes. Blood 2010; 117:1851-60. [PMID: 21148810 DOI: 10.1182/blood-2010-05-287474] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
During innate immune responses, the inflammatory CC chemokine receptors CCR1, CCR2, and CCR5 mediate the recruitment of blood monocytes to infected tissues by promoting cell migration in response to chemokines CCL2-5. Toll-like receptors also play an essential role, allowing pathogen recognition by the recruited monocytes. Here, we demonstrate that Toll-like receptor 2 (TLR2) stimulation by lipoteichoic acid (LTA) from Staphylococcus aureus leads to gradual down-modulation of CCR1, CCR2, and CCR5 from the plasma membrane of human blood-isolated monocytes and inhibits chemotaxis. Interestingly, LTA does not promote rapid desensitization of chemokine-mediated calcium responses. We found that the TLR2 crosstalk with chemokine receptors is not dependent on the Toll/interleukin-1 receptor domain-containing adaptor protein, but instead involves phospholipase C, the small G protein Rac1, and is phorbol ester sensitive. Activation of this pathway by LTA lead to β-arrestin-mediated endocytosis of Ser349-phosphorylated CCR5 into recycling endosomes, as does CCL5 treatment. However, LTA-induced internalization of CCR5 is a slower process associated with phospholipase C-mediated and phorbol ester-sensitive phosphorylation. Overall, our data indicate that TLR2 negatively regulates CCR1, CCR2, and CCR5 on human blood monocytes by activating the machinery used to support chemokine-dependent down-modulation and provide a molecular mechanism for inhibiting monocyte migration after pathogen recognition.
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22
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Irie K, Yanagita RC, Nakagawa Y. Challenges to the development of bryostatin-type anticancer drugs based on the activation mechanism of protein kinase Cδ. Med Res Rev 2010; 32:518-35. [DOI: 10.1002/med.20220] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Kazuhiro Irie
- Division of Food Science and Biotechnology; Graduate School of Agriculture; Kyoto University; Kitashirakawa Oiwake-cho, Sakyo-ku Kyoto Japan
| | - Ryo C. Yanagita
- Division of Food Science and Biotechnology; Graduate School of Agriculture; Kyoto University; Kitashirakawa Oiwake-cho, Sakyo-ku Kyoto Japan
| | - Yu Nakagawa
- Synthetic Cellular Chemistry Laboratory; Advanced Science Institute; RIKEN; Wako-shi Saitama Japan
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23
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Adhikary G, Chew YC, Reece EA, Eckert RL. PKC-delta and -eta, MEKK-1, MEK-6, MEK-3, and p38-delta are essential mediators of the response of normal human epidermal keratinocytes to differentiating agents. J Invest Dermatol 2010; 130:2017-30. [PMID: 20445555 DOI: 10.1038/jid.2010.108] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Previous studies suggest that the novel protein kinase C (PKC) isoforms initiate a mitogen-activated protein kinase (MAPK) signaling cascade that regulates keratinocyte differentiation. However, assigning these functions has relied on treatment with pharmacologic inhibitors and/or manipulating kinase function using overexpression of wild-type or dominant-negative kinases. As these methods are not highly specific, an obligatory regulatory role for individual kinases has not been assigned. In this study, we use small interfering RNA knockdown to study the role of individual PKC isoforms as regulators of keratinocyte differentiation induced by the potent differentiating stimulus, 12-O-tetradecanoylphorbol-13-acetate (TPA). PKC-delta knockdown reduces TPA-activated involucrin promoter activity, nuclear activator protein-1 factor accumulation and binding to DNA, and cell morphology change. Knockdown of PKC downstream targets, including MEKK-1, MEK-6, MEK-3, or p38-delta, indicates that these kinases are required for these responses. Additional studies indicate that knockdown of PKC-eta inhibits TPA-dependent involucrin promoter activation. In contrast, knockdown of PKC-alpha (a classical PKC isoform) or PKC-epsilon (a novel isoform) does not inhibit these TPA-dependent responses. Further studies indicate that PKC-delta is required for calcium and green tea polyphenol-dependent regulation of end responses. These findings are informative as they suggest an essential role for selected PKC and MAPK cascade enzymes in mediating a range of end responses to a range of differentiation stimuli in keratinocytes.
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Affiliation(s)
- Gautam Adhikary
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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24
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Orisme W, Li J, Goldmann T, Bolch S, Wolfrum U, Smith WC. Light-dependent translocation of arrestin in rod photoreceptors is signaled through a phospholipase C cascade and requires ATP. Cell Signal 2010; 22:447-56. [PMID: 19887106 DOI: 10.1016/j.cellsig.2009.10.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 10/26/2009] [Accepted: 10/27/2009] [Indexed: 10/20/2022]
Abstract
Partitioning of cellular components is a critical mechanism by which cells can regulate their activity. In rod photoreceptors, light induces a large-scale translocation of arrestin from the inner segments to the outer segments. The purpose of this project is to elucidate the signaling pathway necessary to initiate arrestin translocation to the outer segments and the mechanism for arrestin translocation. Mouse retinal organotypic cultures and eyes from transgenic Xenopus tadpoles expressing a fusion of GFP and rod arrestin were treated with both activators and inhibitors of proteins in the phosphoinositide pathway. Confocal microscopy was used to image the effects of the pharmacological agents on arrestin translocation in rod photoreceptors. Retinas were also depleted of ATP using potassium cyanide to assess the requirement for ATP in arrestin translocation. In this study, we demonstrate that components of the G-protein-linked phospholipase C (PLC) pathway play a role in initiating arrestin translocation. Our results show that arrestin translocation can be stimulated by activators of PLC and protein kinase C (PKC), and by cholera toxin in the absence of light. Arrestin translocation to the outer segments is significantly reduced by inhibitors of PLC and PKC. Importantly, we find that treatment with potassium cyanide inhibits arrestin translocation in response to light. Collectively, our results suggest that arrestin translocation is initiated by a G-protein-coupled cascade through PLC and PKC signaling. Furthermore, our results demonstrate that at least the initiation of arrestin translocation requires energy input.
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Affiliation(s)
- Wilda Orisme
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610-0284, USA
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25
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Poon HY, Stone JC. Functional links between diacylglycerol and phosphatidylinositol signaling systems in human leukocyte-derived cell lines. Biochem Biophys Res Commun 2009; 390:1395-401. [PMID: 19896467 DOI: 10.1016/j.bbrc.2009.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 11/01/2009] [Indexed: 01/29/2023]
Abstract
In leukocytes, diacylglycerol (DAG) regulates the small GTPase Ras through the agency of Ras guanyl releasing proteins (RasGRPs). Ras is thought to regulate phosphatidylinositol 3-kinase (PI3K). Therefore, DAG signaling is hypothesized to impact PI3K activity. The DAG analogue "pico" was used to activate RasGRPs in leukocyte-derived cell lines. PI3K signaling was monitored using antibodies that recognize the activated form of the PI3K-regulated protein kinase Akt. Diverse responses were documented. Some cell lines exhibit a DAG analogue-stimulated increase in phospho-Akt but this response proceeded even when Ras activation was blocked. In some Epstein-Barr virus-associated malignant cell lines and transformed B cells, high basal phospho-Akt was decreased by DAG analogue treatment. The pan-PKC inhibitor Bisindolymaleimide I blocked this effect. Basal phospho-Akt was also decreased by treatment with Go6976, an inhibitor of conventional protein kinase C and protein kinase D. While the proposed RasGRP-Ras-PI3K-Akt signaling axis may operate in some situations, our results indicate that alternative links between DAG targets such as protein kinases and the PI3K signaling system are more prominent.
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Affiliation(s)
- Ho Y Poon
- Department of Biochemistry, University of Alberta, Edmonton Alberta, Canada T6G 2H7
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26
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Giusto NM, Pasquaré SJ, Salvador GA, Ilincheta de Boschero MG. Lipid second messengers and related enzymes in vertebrate rod outer segments. J Lipid Res 2009; 51:685-700. [PMID: 19828910 DOI: 10.1194/jlr.r001891] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Rod outer segments (ROSs) are specialized light-sensitive organelles in vertebrate photoreceptor cells. Lipids in ROS are of considerable importance, not only in providing an adequate environment for efficient phototransduction, but also in originating the second messengers involved in signal transduction. ROSs have the ability to adapt the sensitivity and speed of their responses to ever-changing conditions of ambient illumination. A major contributor to this adaptation is the light-driven translocation of key signaling proteins into and out of ROS. The present review shows how generation of the second lipid messengers from phosphatidylcholine, phosphatidic acid, and diacylglycerol is modulated by the different illumination states in the vertebrate retina. Findings suggest that the light-induced translocation of phototransduction proteins influences the enzymatic activities of phospholipase D, lipid phosphate phosphatase, diacylglyceride lipase, and diacylglyceride kinase, all of which are responsible for the generation of the second messenger molecules.
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Affiliation(s)
- Norma M Giusto
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina.
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27
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Keck GE, Li W, Kraft MB, Kedei N, Lewin NE, Blumberg PM. The bryostatin 1 A-ring acetate is not the critical determinant for antagonism of phorbol ester-induced biological responses. Org Lett 2009; 11:2277-80. [PMID: 19419164 DOI: 10.1021/ol900585t] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The contribution of the A-ring C(7) acetate to the function of bryostatin 1 has been investigated through synthesis and biological evaluation of an analogue incorporating this feature into the bryopyran core structure. No enhanced binding affinity for protein kinase C (PKC) was observed, relative to previously characterized analogues lacking the C(7) acetate. Functional assays showed biological responses characteristic of those induced by the phorbol ester PMA and distinctly different from those observed with bryostatin 1.
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Affiliation(s)
- Gary E Keck
- University of Utah, Department of Chemistry, Salt Lake City, Utah 84112, USA.
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28
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Salamat Z, Sullivan JT. Involvement of protein kinase C signalling and mitogen-activated protein kinase in the amebocyte-producing organ of Biomphalaria glabrata (Mollusca). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2009; 33:725-727. [PMID: 19183562 DOI: 10.1016/j.dci.2009.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 01/04/2009] [Accepted: 01/09/2009] [Indexed: 05/27/2023]
Abstract
Mechanisms that regulate hemocyte production in molluscs, at either the organismal or cellular levels, are not well understood. In the present study, 24-h saline cultures of the amebocyte-producing organ (APO) of the schistosome-transmitting snail Biomphalaria glabrata were used to test for the potential involvement of protein kinase C (PKC) signalling in hematopoiesis. Exposure to phorbol myristate acetate (PMA), an activator of PKC, resulted in an increase in the number of dividing hematopoietic cells in APOs from schistosome-resistant Salvador snails. PMA-induced cell division was blocked by treatment with U0126, an inhibitor of the mitogen-activated protein kinase kinase, MEK1/2. These results suggest that PKC-induced activation of the mitogen-activated protein kinase, ERK1/2, is involved in cell division in the APO.
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Affiliation(s)
- Zahra Salamat
- Department of Biology, University of San Francisco, San Francisco, CA 94117, USA
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29
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Fibronectin promotes the phorbol 12-myristate 13-acetate-induced macrophage differentiation in myeloid leukemia cells. Int J Hematol 2009; 89:167-172. [DOI: 10.1007/s12185-008-0243-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 12/01/2008] [Accepted: 12/04/2008] [Indexed: 01/12/2023]
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30
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Blumberg PM, Kedei N, Lewin NE, Yang D, Czifra G, Pu Y, Peach ML, Marquez VE. Wealth of opportunity - the C1 domain as a target for drug development. Curr Drug Targets 2008; 9:641-52. [PMID: 18691011 PMCID: PMC3420355 DOI: 10.2174/138945008785132376] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The diacylglycerol-responsive C1 domains of protein kinase C and of the related classes of signaling proteins represent highly attractive targets for drug development. The signaling functions that are regulated by C1 domains are central to cellular control, thereby impacting many pathological conditions. Our understanding of the diacylglycerol signaling pathways provides great confidence in the utility of intervention in these pathways for treatment of cancer and other conditions. Multiple compounds directed at these signaling proteins, including compounds directed at the C1 domains, are currently in clinical trials, providing strong validation for these targets. Extensive understanding of the structure and function of C1 domains, coupled with detailed insights into the molecular details of ligand - C1 domain interactions, provides a solid basis for rational and semi-rational drug design. Finally, the complexity of the factors contributing to ligand - C1 domain interactions affords abundant opportunities for manipulation of selectivity; indeed, substantially selective compounds have already been identified.
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Affiliation(s)
- P M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Center, Bethesda, MD 20892, USA.
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31
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Suzuki K, Kosho I, Namiki H. Characterization of the unique regulatory mechanisms of phorbol ester-induced polymorphonuclear leukocyte spreading in an acidified environment. Eur J Pharmacol 2008; 588:301-8. [DOI: 10.1016/j.ejphar.2008.04.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 04/02/2008] [Accepted: 04/09/2008] [Indexed: 11/28/2022]
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Abstract
Major advances in understanding regulated mucin secretion from airway goblet cells have been made in the past decade in the areas of pharmacology and basic cell biology. For instance, it is now appreciated that nucleotide agonists acting locally through P2Y purinoceptors on apical membranes of surface goblet cells provide the major regulatory system for mucin secretion. Similarly, Clara cells, the primary secretory cell in the mouse airways (and human small airways), are now recognized as major mucin-secreting cells. In Clara cells, the relative lack of staining for mucosubstances reflects essentially equal baseline rates of mucin synthesis and secretion, with little to no accumulation of mucin granules in storage pools. During mucous metaplasia induced under inflammatory conditions, mucin synthesis is massively upregulated in Clara cells, and stored mucin granules come to dominate the secretory cell phenotype. More importantly, we have seen a transition in the past few years from a pharmacological focus on regulated mucin secretion to a more molecular mechanistic focus that has great promise going forward. In part, these advances are occurring through the use of well-differentiated primary human bronchial epithelial cell cultures, but recent work in mouse models perhaps has had the most important impact. Emerging data from Munc13-2- and synaptotagmin 2-deficient mouse models represent the first direct, molecular-level manipulations of proteins involved in regulated secretory cell mucin secretion. These new data indicate that Munc13-2 is responsible for regulating a baseline mucin secretory pathway in the airways and is not essential for purinergic agonist-induced mucin secretion. In contrast, synaptotagmin 2, a fast Ca2+ sensor for the SNARE complex, is essential for regulated secretion. Interestingly, these early results suggest that there are two pathways for excocytic mucin release from goblet cells.
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Affiliation(s)
- C William Davis
- Cystic Fibrosis/Pulmonary Research & Treatment Center, University of North Carolina, Chapel Hill, NC 27599-7248, USA.
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Solodukhin AS, Kretsinger RH, Sando JJ. Initial three-dimensional reconstructions of protein kinase C δ from two-dimensional crystals on lipid monolayers. Cell Signal 2007; 19:2035-45. [PMID: 17604605 DOI: 10.1016/j.cellsig.2007.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 05/22/2007] [Accepted: 05/25/2007] [Indexed: 01/06/2023]
Abstract
Two-dimensional crystals of protein kinase C delta (PKCdelta) and of its regulatory domain (RDdelta) were grown on lipid monolayers and analyzed by electron microscopy at tilt angles varying from -50 degrees to +55 degrees. Although the crystals exhibit pseudo-3-fold symmetry, analysis of difference phase residuals indicates that there is only one way to align the crystals for merging so the data were processed in plane group P1. Three-dimensional reconstructions generated for several two-dimensional crystals each of PKCdelta and RDdelta show good agreement and are consistent with membrane attachment via a single C1 subdomain, a small surface contact by one or two loops from the C2 domain, and, in intact PKCdelta, a small appendage from the catalytic domain, probably V5. Two-dimensional crystallography with three-dimensional reconstruction should be suitable for examination of additional PKC isozymes and for analysis of the enzymes bound to substrates and other proteins.
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34
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Feng H, Ren M, Chen L, Rubin CS. Properties, Regulation, and in Vivo Functions of a Novel Protein Kinase D. J Biol Chem 2007; 282:31273-88. [PMID: 17728253 DOI: 10.1074/jbc.m701532200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase D (PKD) isoforms are protein kinase C effectors in signaling cascades controlled by diacylglycerol (DAG). All PKDs are regulated by DAG/phorbol 12-myristate 13-acetate-binding C1 domains and an activation loop (A-loop). To understand how PKD isoforms diversify DAG signaling networks, it is essential to determine redundant and novel properties of their regulatory domains, characterize factors controlling PKD gene expression, and discover their in vivo physiological roles. Studies on a novel PKD, Caenorhabditis elegans DKF-2 (D kinase family-2), addressed these topics. The C1b domain mediates phorbol 12-myristate 13-acetate-induced translocation and activation of DKF-2. However, when DAG is elevated, C1a and C1b contribute equally to targeting/activation of DKF-2. DKF-2 C1 domains do not inhibit catalytic activity; they mediate delivery of DKF-2 to a membrane where protein kinase C phosphorylates Ser(925) and Ser(929) in the A-loop. This potently stimulates DKF-2 catalytic activity. Phosphorylation of Ser(925) alone switches on 70% of maximal kinase activity. Persistent phosphorylation of Ser(929) tags DKF-2 for proteasomal degradation; Ser(P)(925) plays a minor role in DKF-2 degradation. GATA enhancer sequences govern DKF-2 expression in intestine in vivo. Adult life span increases 40% in animals lacking DKF-2. In thermally stressed wild type animals, the DAF-16 transcription factor is segregated from the nuclei of adult intestinal cells. In contrast, DAF-16 enters adult intestinal nuclei of DKF-2-deficient, thermally stressed animals, where it can trigger gene transcription that protects against various insults. The results suggest a mechanism for increased longevity and show that a PKD links DAG signals to regulation of stress responses and life span.
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Affiliation(s)
- Hui Feng
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Hartsock A, Nelson WJ. Adherens and tight junctions: structure, function and connections to the actin cytoskeleton. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1778:660-9. [PMID: 17854762 PMCID: PMC2682436 DOI: 10.1016/j.bbamem.2007.07.012] [Citation(s) in RCA: 1025] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 07/12/2007] [Accepted: 07/19/2007] [Indexed: 02/07/2023]
Abstract
Adherens junctions and Tight junctions comprise two modes of cell-cell adhesion that provide different functions. Both junctional complexes are proposed to associate with the actin cytoskeleton, and formation and maturation of cell-cell contacts involves reorganization of the actin cytoskeleton. Adherens junctions initiate cell-cell contacts, and mediate the maturation and maintenance of the contact. Adherens junctions consist of the transmembrane protein E-cadherin, and intracellular components, p120-catenin, beta-catenin and alpha-catenin. Tight junctions regulate the paracellular pathway for the movement of ions and solutes in-between cells. Tight junctions consist of the transmembrane proteins occludin and claudin, and the cytoplasmic scaffolding proteins ZO-1, -2, and -3. This review discusses the binding interactions of the most studied proteins that occur within each of these two junctional complexes and possible modes of regulation of these interactions, and the different mechanisms that connect and regulate interactions with the actin cytoskeleton.
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Affiliation(s)
- Andrea Hartsock
- Department of Molecular and Cellular Physiology, Stanford University
| | - W. James Nelson
- Department of Molecular and Cellular Physiology, Stanford University
- Department of Biological Sciences, Stanford University
- Corresponding Author: Department of Biological Sciences, The James H. Clark Center, The Bio-X Program, 318 Campus Drive (E200-B), Stanford University, Stanford, CA 94305-5430. Tel: 650-725-7596 Fax: 650-725-8021,
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36
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Genestra M. Oxyl radicals, redox-sensitive signalling cascades and antioxidants. Cell Signal 2007; 19:1807-19. [PMID: 17570640 DOI: 10.1016/j.cellsig.2007.04.009] [Citation(s) in RCA: 349] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Accepted: 04/23/2007] [Indexed: 01/20/2023]
Abstract
Oxidative stress is an increase in the reduction potential or a large decrease in the reducing capacity of the cellular redox couples. A particularly destructive aspect of oxidative stress is the production of reactive oxygen species (ROS), which include free radicals and peroxides. Some of the less reactive of these species can be converted by oxidoreduction reactions with transition metals into more aggressive radical species that can cause extensive cellular damage. In animals, ROS may influence cell proliferation, cell death (either apoptosis or necrosis) and the expression of genes, and may be involved in the activation of several signalling pathways, activating cell signalling cascades, such as those involving mitogen-activated protein kinases. Most of these oxygen-derived species are produced at a low level by normal aerobic metabolism and the damage they cause to cells is constantly repaired. The cellular redox environment is preserved by enzymes and antioxidants that maintain the reduced state through a constant input of metabolic energy. This review summarizes current studies that have been regarding the production of ROS and the general redox-sensitive targets of cell signalling cascades.
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Affiliation(s)
- Marcelo Genestra
- Department of Immunology, Oswaldo Cruz Institute/FIOCRUZ, Avenida Brasil, 4365-Manguinhos, Rio de Janeiro, CEP 21045-900, RJ-Brazil.
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37
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Bond JA, Gescher AJ, Verschoyle RD, Lemoine NR, Errington R, Wiltshire M, Smith PJ, Wynford-Thomas D. Cytotoxic action of phorbol esters on human pancreatic cancer cells. Int J Cancer 2007; 121:1445-54. [PMID: 17582609 DOI: 10.1002/ijc.22869] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We previously showed that phorbol esters are cytotoxic to human thyroid epithelial cells expressing a mutant RAS oncogene. Here we explore the generality of this finding using cells derived from pancreatic cancer, which, like thyroid, shows a high frequency of RAS mutation, but is a much greater cause of cancer mortality. The response to phorbol myristate acetate (PMA) and related agents was assessed on a panel of 9 pancreatic cancer cell lines, using a range of assays for cell growth and death in vitro and in vivo. In most lines, PMA induced non-apoptotic cell death which was, surprisingly, independent of its "classic" target, protein kinase C. With 24 hr exposure, the IC(50) in the most sensitive line (Aspc-1) was <1 ng/ml (1.6 nM), with survival undetectable at concentrations >/=>/=16 nM, and after only 1 hr exposure the IC(50) was still </=</=16 nM. Interestingly, the efficacy of a second phorbol ester, phorbol dibutyrate, was much lower, and the PMA analogue bryostatin-1, which is in clinical trials against other tumour types, was totally inactive. Pre-treatment of Aspc-1 cells with PMA before subcutaneous inoculation into nude mice prevented, or greatly retarded, subsequent xenograft tumour growth. Furthermore, treatment of established tumours with a single peri-tumoral injection of PMA induced extensive cell death and arrested tumour development. Taken together with recent Phase 1 clinical studies, these data suggest that activity against pancreatic cancer will be attainable by systemic administration of PMA, and point to potential novel therapeutic targets for this highly aggressive cancer.
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Affiliation(s)
- Jane A Bond
- Department of Pathology, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom
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38
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Marchet A, Mocellin S, Belluco C, Ambrosi A, DeMarchi F, Mammano E, Digito M, Leon A, D'Arrigo A, Lise M, Nitti D. Gene expression profile of primary gastric cancer: towards the prediction of lymph node status. Ann Surg Oncol 2006; 14:1058-64. [PMID: 17106627 DOI: 10.1245/s10434-006-9090-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 06/05/2006] [Accepted: 06/05/2006] [Indexed: 12/17/2022]
Abstract
BACKGROUND The identification of gastric tumors associated with a higher risk of lymph node metastasis could help surgeons select patients who may benefit from extended lymph node dissection. The aim of this study was to screen the genome in the search of primary gastric cancer gene expression profiles that might predict lymph node status. METHODS The gene expression profile was evaluated in frozen tumor samples obtained from 32 patients with primary gastric adenocarcinomas. The array consisted of a duplicated spot panel of 5,541 human genes. To classify node-positive (N+) and node-negative (N-) cases, a logistic regression model was fitted optimizing the Akaike Information Criteria after a stepwise gene selection. The accuracy was evaluated by means of leave-one-out cross validation. RESULTS All patients underwent radical gastrectomy and extended lymphadenectomy. Of all the cases, 21 were N+ and 11 demonstrated no lymph node involvement (N-). After quality filtering, the analysis of variance selected a set of 136 genes potentially correlated with nodal involvement (P value <.05). Of these 136 genes, 5 were differentially expressed (adjusted P value <.05). After a stepwise gene selection, only three genes (Bik, aurora kinase B, eIF5A2) were retained in the logistic model, which could correctly predict lymph node status in 30 of 32 cases. CONCLUSIONS If our findings were confirmed, the identified gene pattern might be used to tailor the extent of lymph node dissection on a single patient basis.
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Affiliation(s)
- Alberto Marchet
- Clinica Chirurgica II, Dipartimento di Scienze Oncologiche e Chirurgiche, Istituto Oncologico Veneto IRCCS and University of Padova, Padova, Italy
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Pu Y, Peach ML, Garfield SH, Wincovitch S, Marquez VE, Blumberg PM. Effects on Ligand Interaction and Membrane Translocation of the Positively Charged Arginine Residues Situated along the C1 Domain Binding Cleft in the Atypical Protein Kinase C Isoforms. J Biol Chem 2006; 281:33773-88. [PMID: 16950780 DOI: 10.1074/jbc.m606560200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The C1 domain zinc finger structure is highly conserved among the protein kinase C (PKC) superfamily members. As the interaction site for the second messenger sn-1,2-diacylglycerol (DAG) and for the phorbol esters, the C1 domain has been an important target for developing selective ligands for different PKC isoforms. However, the C1 domains of the atypical PKC members are DAG/phorbol ester-insensitive. Compared with the DAG/phorbol ester-sensitive C1 domains, the rim of the binding cleft of the atypical PKC C1 domains possesses four additional positively charged arginine residues (at positions 7, 10, 11, and 20). In this study, we showed that mutation to arginines of the four corresponding sites in the C1b domain of PKCdelta abolished its high potency for phorbol 12,13-dibutyrate in vitro, with only marginal remaining activity for phorbol 12-myristate 13-acetate in vivo. We also demonstrated both in vitro and in vivo that the loss of potency to ligands was cumulative with the introduction of the arginine residues along the rim of the binding cavity rather than the consequence of loss of a single, specific residue. Computer modeling reveals that these arginine residues reduce access of ligands to the binding cleft and change the electrostatic profile of the C1 domain surface, whereas the basic structure of the binding cleft is still maintained. Finally, mutation of the four arginine residues of the atypical PKC C1 domains to the corresponding residues in the deltaC1b domain conferred response to phorbol ester. We speculate that the arginine residues of the C1 domain of atypical PKCs may provide an opportunity for the design of ligands selective for the atypical PKCs.
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Affiliation(s)
- Yongmei Pu
- Laboratory of Cellular Carcinogenesis and Tumor Promotion, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA
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Corbalán-García S, Gómez-Fernández JC. Protein kinase C regulatory domains: the art of decoding many different signals in membranes. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:633-54. [PMID: 16809062 DOI: 10.1016/j.bbalip.2006.04.015] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 04/27/2006] [Accepted: 04/28/2006] [Indexed: 11/29/2022]
Abstract
Protein kinase C (PKC) is a member of a family of Ser/Thr phosphotransferases that are involved in many cellular signaling pathways. These enzymes possess two regulatory domains, C1 and C2, that are the targets of different second messengers. The purpose of this review is to describe in molecular terms the diverse mechanisms of activation of PKCs in the light of very significant advances made in this field over recent years. The role of some critical amino acid residues concerning activation of the enzymes and their location within known structures of isolated domains will be presented. For example, the recently deduced 3D structures of the C2 domains show that these domains can additionally act as PtdIns(4,5)P(2)-binding or phosphotyrosine-binding modules depending on the isoenzyme. All these capacities to play different roles in the cell wide web of signals underline the notion that we are dealing with a multifunctional family of enzymes which, after 30 years of investigation, we are just beginning to understand.
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Affiliation(s)
- Senena Corbalán-García
- Dpto. de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad de Murcia, Apdo. 4021, E-30100 Murcia, Spain.
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