1
|
Sasahara T, Satomura K, Tada M, Kakita A, Hoshi M. Alzheimer's Aβ assembly binds sodium pump and blocks endothelial NOS activity via ROS-PKC pathway in brain vascular endothelial cells. iScience 2021; 24:102936. [PMID: 34458695 PMCID: PMC8379508 DOI: 10.1016/j.isci.2021.102936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/24/2021] [Accepted: 07/29/2021] [Indexed: 01/12/2023] Open
Abstract
Amyloid β-protein (Aβ) may contribute to worsening of Alzheimer's disease (AD) through vascular dysfunction, but the molecular mechanism involved is unknown. Using ex vivo blood vessels and primary endothelial cells from human brain microvessels, we show that patient-derived Aβ assemblies, termed amylospheroids (ASPD), exist on the microvascular surface in patients' brains and inhibit vasorelaxation through binding to the α3 subunit of sodium, potassium-ATPase (NAKα3) in caveolae on endothelial cells. Interestingly, NAKα3 is also the toxic target of ASPD in neurons. ASPD-NAKα3 interaction elicits neurodegeneration through calcium overload in neurons, while the same interaction suppresses vasorelaxation by increasing the inactive form of endothelial nitric oxide synthase (eNOS) in endothelial cells via mitochondrial ROS and protein kinase C, independently of the physiological relaxation system. Thus, ASPD may contribute to both neuronal and vascular pathologies through binding to NAKα3. Therefore, blocking the ASPD-NAKα3 interaction may be a useful target for AD therapy.
Collapse
Affiliation(s)
- Tomoya Sasahara
- Department for Brain and Neurodegenerative Disease Research, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, CLIK 6F 6-3-7 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- TAO Health Life Pharma Co., Ltd., Med-Pharma Collaboration Bldg, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kaori Satomura
- Department for Brain and Neurodegenerative Disease Research, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, CLIK 6F 6-3-7 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- TAO Health Life Pharma Co., Ltd., Med-Pharma Collaboration Bldg, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Mari Tada
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Minako Hoshi
- Department for Brain and Neurodegenerative Disease Research, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, CLIK 6F 6-3-7 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| |
Collapse
|
2
|
Nelson RK, Ya-Ping J, Gadbery J, Abedeen D, Sampson N, Lin RZ, Frohman MA. Phospholipase D2 loss results in increased blood pressure via inhibition of the endothelial nitric oxide synthase pathway. Sci Rep 2017; 7:9112. [PMID: 28831159 PMCID: PMC5567230 DOI: 10.1038/s41598-017-09852-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 07/14/2017] [Indexed: 11/10/2022] Open
Abstract
The Phospholipase D (PLD) superfamily is linked to neurological disease, cancer, and fertility, and a recent report correlated a potential loss-of-function PLD2 polymorphism with hypotension. Surprisingly, PLD2 -/- mice exhibit elevated blood pressure accompanied by associated changes in cardiac performance and molecular markers, but do not have findings consistent with the metabolic syndrome. Instead, expression of endothelial nitric oxide synthase (eNOS), which generates the potent vasodilator nitric oxide (NO), is decreased. An eNOS inhibitor phenocopied PLD2 loss and had no further effect on PLD2 -/- mice, confirming the functional relationship. Using a human endothelial cell line, PLD2 loss of function was shown to lower intracellular free cholesterol, causing upregulation of HMG Co-A reductase, the rate-limiting enzyme in cholesterol synthesis. HMG Co-A reductase negatively regulates eNOS, and the PLD2-deficiency phenotype of decreased eNOS expression and activity could be rescued by cholesterol supplementation and HMG Co-A reductase inhibition. Together, these findings identify a novel pathway through which the lipid signaling enzyme PLD2 regulates blood pressure, creating implications for on-going therapeutic development of PLD small molecule inhibitors. Finally, we show that the human PLD2 polymorphism does not trigger eNOS loss, but rather creates another effect, suggesting altered functioning for the allele.
Collapse
Affiliation(s)
- Rochelle K Nelson
- The Graduate Program in Physiology & Biophysics, Stony Brook University, New York, USA
| | - Jiang Ya-Ping
- Department of Physiology & Biophysics, Stony Brook University, New York, USA
| | - John Gadbery
- Biochemistry and Structural Biology, Stony Brook University, New York, USA
| | - Danya Abedeen
- The Undergraduate Program in Biochemistry, Stony Brook University, New York, USA
| | - Nicole Sampson
- Biochemistry and Structural Biology, Stony Brook University, New York, USA
- Department of Chemistry, Stony Brook University, New York, USA
| | - Richard Z Lin
- Department of Physiology & Biophysics, Stony Brook University, New York, USA
- Medical Service, Northport Veterans Affairs Medical Center, Northport, NY, USA
| | - Michael A Frohman
- Department of Pharmacological Sciences, Stony Brook University, New York, USA.
| |
Collapse
|
3
|
AlMatar M, Makky EA. Cladosporium cladosporioides from the perspectives of medical and biotechnological approaches. 3 Biotech 2016; 6:4. [PMID: 28330073 PMCID: PMC4697913 DOI: 10.1007/s13205-015-0323-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 06/16/2015] [Indexed: 11/24/2022] Open
Abstract
Fungi are important natural product sources that have enormous potential for the production of novel compounds for use in pharmacology, agricultural applications and industry. Compared with other natural sources such as plants, fungi are highly diverse but understudied. However, research on Cladosporium cladosporioides revealed the existence of bioactive products such as p-methylbenzoic acid, ergosterol peroxide (EP) and calphostin C as well as enzymes including pectin methylesterase (PME), polygalacturonase (PG) and chlorpyrifos hydrolase. p-Methylbenzoic acid has ability to synthesise 1,5-benzodiazepine and its derivatives, polyethylene terephthalate and eicosapentaenoic acid. EP has anticancer, antiangiogenic, antibacterial, anti-oxidative and immunosuppressive properties. Calphostin C inhibits protein kinase C (PKC) by inactivating both PKC-epsilon and PKC-alpha. In addition, calphostin C stimulates apoptosis in WEHI-231 cells and vascular smooth muscle cells. Based on the stimulation of endoplasmic reticulum stress in some types of cancer, calphostin C has also been evaluated as a potential photodynamic therapeutic agent. Methylesterase (PME) and PG have garnered attention because of their usage in the food processing industry and significant physiological function in plants. Chlorpyrifos, a human, animal and plant toxin, can be degraded and eliminated by chlorpyrifos hydrolase.
Collapse
Affiliation(s)
- Manaf AlMatar
- Department of Biotechnology, Institute of Natural and Applied Sciences (Fen Bilimleri Enstitüsü), Cukurova University, Rectorate 01330 Balcali, Adana, Turkey.
| | - Essam A Makky
- Department of Biotechnology, Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang (UMP), 26300, Gambang, Kuantan, Malaysia
| |
Collapse
|
4
|
Scott SA, Mathews TP, Ivanova PT, Lindsley CW, Brown HA. Chemical modulation of glycerolipid signaling and metabolic pathways. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1060-84. [PMID: 24440821 DOI: 10.1016/j.bbalip.2014.01.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 01/06/2014] [Accepted: 01/07/2014] [Indexed: 01/04/2023]
Abstract
Thirty years ago, glycerolipids captured the attention of biochemical researchers as novel cellular signaling entities. We now recognize that these biomolecules occupy signaling nodes critical to a number of physiological and pathological processes. Thus, glycerolipid-metabolizing enzymes present attractive targets for new therapies. A number of fields-ranging from neuroscience and cancer to diabetes and obesity-have elucidated the signaling properties of glycerolipids. The biochemical literature teems with newly emerging small molecule inhibitors capable of manipulating glycerolipid metabolism and signaling. This ever-expanding pool of chemical modulators appears daunting to those interested in exploiting glycerolipid-signaling pathways in their model system of choice. This review distills the current body of literature surrounding glycerolipid metabolism into a more approachable format, facilitating the application of small molecule inhibitors to novel systems. This article is part of a Special Issue entitled Tools to study lipid functions.
Collapse
Affiliation(s)
- Sarah A Scott
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Thomas P Mathews
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Pavlina T Ivanova
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - H Alex Brown
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA.
| |
Collapse
|
5
|
Yin H, Gui Y, Du G, Frohman MA, Zheng XL. Dependence of phospholipase D1 multi-monoubiquitination on its enzymatic activity and palmitoylation. J Biol Chem 2010; 285:13580-8. [PMID: 20189990 DOI: 10.1074/jbc.m109.046359] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phospholipase D (PLD) is an important lipase in many cellular processes, including vesicular trafficking, cell survival, and cell migration. In the present study, we show that PLD1, but not PLD2, is posttranslationally modified by multi-monoubiquitination. Intriguingly, suppression of lipase activity either by mutation of the HKD motif (PLD1 H896R, K898R, or D903A) or the phosphatidylinositol 4,5-bisphosphate binding motif (PLD1 R691G,R695G) or through use of PLD-selective inhibitors impaired the ubiquitination of PLD1, although stimulation of lipase activity by phorbol 12-myristate 13-acetate did not enhance its ubiquitination. A palmitoylation-deficient mutant PLD1 allele, which exhibits altered patterns of vesicular trafficking, had significantly lower levels of monoubiquitination. In addition, the expression of ubiquitin-fused PLD1 induced aberrantly enlarged vesicles partially co-localized with the Golgi complex but not with early endosomes. The altered localization was reduced by the K898R mutation, suggesting a role of multi-monoubiquitination in PLD1 subcellular localization. Surprisingly, the degradation of PLD1, but not of PLD1 K898R or PLD2, was blocked by inhibitors of proteasomes but not by inhibitors of lysosomes or other proteases, suggesting a role of the ubiquitination in proteasomal degradation of PLD1. In summary, our studies show that PLD1, but not PLD2, is multi-monoubiquitinated. The ubiquitination modification might represent a novel regulatory mechanism in PLD1 functioning, particularly in the context of subcellular trafficking between different membrane compartments.
Collapse
Affiliation(s)
- Hao Yin
- Smooth Muscle Research Group, Libin Cardiovascular Institute of Alberta, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | | | | | | | | |
Collapse
|
6
|
Cerium elicitor-induced phosphatidic acid triggers apoptotic signaling development in Taxus cuspidata cell suspension cultures. Chem Phys Lipids 2009; 159:13-20. [PMID: 19428358 DOI: 10.1016/j.chemphyslip.2009.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 01/25/2009] [Accepted: 02/05/2009] [Indexed: 01/06/2023]
Abstract
Degradation of membrane phospholipids is associated with apoptotic responses, but the signaling development of this degradation is not well understood. Cerium (Ce(4+)), an important rare earth element, induces cellular apoptosis and taxol biosynthesis in Taxus cuspidata suspension cultures. Here, using mass spectrometry and biochemical technique, we demonstrated that the phospholipase D (PLD) was rapidly activated by Ce(4+) and hydrolyzed structural phospholipids to generate lipid signal molecule, phosphatidic acid (PA). 1-Butanol, an antagonist of PLD-dependent PA production, blocked the biphasic burst of superoxide anions (O2(*-)) and thus mitigated cellular apoptosis. The time-course analysis of PA accumulation and ERK-like mitogen-activated protein kinase (MAPK) regulation indicated PA generation preceded MAPK activation, suggesting that the rapid accumulation of PA might be required for the initial MAPK activity. After 2h of Ce(4+) elicitation, however, PA-induced O2(*-) burst, forming a negative regulation to MAPK activity, which in turn led to apoptotic signaling development.
Collapse
|
7
|
Gui Y, Zheng XL, Zheng J, Walsh MP. Inhibition of rat aortic smooth muscle contraction by 2-methoxyestradiol. Am J Physiol Heart Circ Physiol 2008; 295:H1935-42. [PMID: 18775847 DOI: 10.1152/ajpheart.00723.2008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies suggest that 2-methoxyestradiol (2-ME), an estrogen metabolite, has a similar inhibitory effect as 17beta-estradiol (E2) on vascular tone. However, it is not known whether 2-ME mediates the effects of E2 or by what mechanism 2-ME regulates smooth muscle contraction. Therefore, we compared the effects of 2-ME and E2 on rat aortic smooth muscle contraction. A preincubation with 2-ME (10 microM) for 1 h inhibited phenylephrine (PE)-induced tension in endothelium-intact, but not -denuded, tissues, whereas E2 inhibited PE-induced contraction in both preparations. The effects of 2-ME and E2 on endothelium-intact preparations were prevented by L-NAME hydrochloride (a nitric oxide synthase inhibitor). The 2-ME treatment reduced PE-induced phosphorylation of the 20-kDa myosin regulatory light chain. The inhibitory effects of 2-ME and E2 were not affected by ICI-182780 (an estrogen receptor antagonist) or actinomycin D (a gene transcription inhibitor); however, the effect of 2-ME, but not E2, was prevented by cycloheximide (a protein synthesis inhibitor). Furthermore, the effect of E2 was not blocked by 1-aminobenzotriazole (a cytochrome P-450 inhibitor) or Ro 41-0960 (a catechol-O-methyltransferase inhibitor). The effect of 2-ME was not mimicked by microtubule-interfering agents (nocodazole or Taxol). We conclude that 2-ME inhibits smooth muscle contractility through an endothelium- and nitric oxide-dependent mechanism, which does not involve estrogen receptors or microtubule disruption. The effect of 2-ME, but not E2, involves de novo protein synthesis. 2-ME does not mediate the inhibitory effect of E2 on smooth muscle contraction. These results support a potentially important role of 2-ME in the regulation of smooth muscle tone in the vasculature.
Collapse
Affiliation(s)
- Yu Gui
- Smooth Muscle Research Group, Department of Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Dr. NW, Calgary, Alberta, T2N 4N1 Canada
| | | | | | | |
Collapse
|
8
|
Calphostin C-induced apoptosis is mediated by a tissue transglutaminase-dependent mechanism involving the DLK/JNK signaling pathway. Cell Death Differ 2008; 15:1522-31. [PMID: 18497756 DOI: 10.1038/cdd.2008.77] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A role for tissue transglutaminase (TG2) and its substrate dual leucine zipper-bearing kinase (DLK), an upstream component of the c-Jun N-terminal kinase (JNK) signaling pathway, has been previously suggested in the apoptotic response induced by calphostin C. In the current study, we directly tested this hypothesis by examining via pharmacological and RNA-interference approaches whether inhibition of expression or activity of TG2, DLK and JNK in mouse NIH 3T3 fibroblasts and human MDA-MB-231 breast cancer epithelial cells affects calphostin C-induced apoptosis. Our experiments with the selective JNK inhibitor SP600125 reveal that calphostin C is capable of causing JNK activation and JNK-dependent apoptosis in both cell lines. Small interfering RNA-mediated depletion of TG2 alone strongly reduces calphostin C action on JNK activity and apoptosis. Consistent with an active role for DLK in this cascade of event, cells deficient in DLK demonstrate a substantial delay of JNK activation and poly-ADP-ribose polymerase (PARP) cleavage in response to calphostin C, whereas overexpression of a recombinant DLK resistant to silencing, but sensitive to TG2-mediated oligomerization, reverses this effect. Importantly, combined depletion of TG2 and DLK further alters calphostin C effects on JNK activity, Bax translocation, caspase-3 activation, PARP cleavage and cell viability, demonstrating an obligatory role for TG2 and DLK in calphostin C-induced apoptosis.
Collapse
|
9
|
Wright MH, Farquhar MJ, Aletrari MO, Ladds G, Hodgkin MN. Identification of caspase 3 motifs and critical aspartate residues in human phospholipase D1b and phospholipase D2a. Biochem Biophys Res Commun 2008; 369:478-84. [PMID: 18298948 DOI: 10.1016/j.bbrc.2008.02.064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 02/09/2008] [Indexed: 11/24/2022]
Abstract
Stimulation of mammalian cells frequently initiates phospholipase D-catalyzed hydrolysis of phosphatidylcholine in the plasma membrane to yield phosphatidic acid (PA) a novel lipid messenger. PA plays a regulatory role in important cellular processes such as secretion, cellular shape change, and movement. A number of studies have highlighted that PLD-based signaling also plays a pro-mitogenic and pro-survival role in cells and therefore anti-apoptotic. We show that human PLD1b and PLD2a contain functional caspase 3 cleavage sites and identify the critical aspartate residues within PLD1b that affect its activation by phorbol esters and attenuate phosphatidylcholine hydrolysis during apoptosis.
Collapse
Affiliation(s)
- Michelle H Wright
- Department of Biological Sciences, University of Warwick, Coventry West Midlands CV4 7AL, UK
| | | | | | | | | |
Collapse
|
10
|
Yang S, Lu SH, Yuan YJ. Lipidomic analysis reveals differential defense responses of Taxus cuspidata cells to two elicitors, methyl jasmonate and cerium (Ce4+). Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1781:123-34. [PMID: 18179778 DOI: 10.1016/j.bbalip.2007.11.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2007] [Revised: 11/21/2007] [Accepted: 11/30/2007] [Indexed: 11/26/2022]
Abstract
Methyl jasmonate (MeJA) and cerium (Ce(4+)) elicitation share common features of increasing taxol accumulation of Taxus cuspidata cells. Interestingly, Ce(4+) induces programmed cell death (PCD), but this phenomenon is not observed with MeJA elicitation. Here, using a lipidomic approach to measure more than 100 membrane glycerophospholipids of T. cuspidata cells quantitatively, we discovered that lysophosphatidylcholine (LysoPC), phosphatidic acid (PA) and phosphatidylcholine were three potential lipid markers that were responsible for the differences between Ce(4+)-induced cells and MeJA-induced cells. Compared with MeJA elicitation, marked increase of phospholipase D (PLD) activity was observed following Ce(4+) elicitation, suggesting that the PLD activation and high concentrations of PA production might mediate the PCD. Rapid increase of phospholipase A(2) (PLA(2)) activity caused the release of fatty acids and LysoPC following Ce(4+) elicitation, which enhanced endogenous jasmonic acid (JA) accumulation. In contrast, PLA(2) activity was poorly induced following MeJA elicitation. PLA(2) inhibitor suppressed not only JA accumulation but also taxol production, suggesting that the PLA(2) activation mediated Ce(4+)-induced taxol production partially through a JA-dependent signaling pathway. These results demonstrate that differential alternation of glycerolphospholipids caused by phospholipases constitutes an important step in cell death response to Ce(4+) and increasing taxol production.
Collapse
Affiliation(s)
- Song Yang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | | | | |
Collapse
|
11
|
Yang S, Qiao B, Lu SH, Yuan YJ. Comparative lipidomics analysis of cellular development and apoptosis in two Taxus cell lines. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:600-12. [PMID: 17428727 DOI: 10.1016/j.bbalip.2007.02.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 02/03/2007] [Accepted: 02/26/2007] [Indexed: 11/20/2022]
Abstract
A comparative lipidomics approach was employed to investigate the changes in membrane phospholipids during the procession of cellular development and apoptosis of two plant cell lines, Taxus cuspidata and Taxus chinensis var. mairei. Analysis of lipids by LC/ESI/MS(n) showed more than 90 phospholipid molecular species and indicated significant differences in the abundance throughout a 3-week period. Phosphatidic acid (PA), phosphatidylcholine (PC) and lysophosphatidylcholine (LysoPC) were three important lipid groups that were responsible for the discrimination between the apoptotic T. chinensis var. mairei and living T. cuspidata cells. Continuous increase of phospholipase D (PLD) activity led to PA production in apoptotic T. chinensis var. mairei cells suggesting that the PLD activation and PA formation mediated the apoptosis. Comparison of the profiles of phosphatidylbutanol (PtdBut) with those of PC or phosphatidylethanolamine (PE) indicated that PC rather than PE was the major substrate of PLD in vivo. These results suggest that the alternation of membrane phospholipids may regulate apoptosis, triggering an increase in taxol production of T. chinensis var. mairei cells.
Collapse
Affiliation(s)
- Song Yang
- Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | | | | | | |
Collapse
|
12
|
Zheng XL, Yuan SG, Peng DQ. Phenotype-specific inhibition of the vascular smooth muscle cell cycle by high glucose treatment. Diabetologia 2007; 50:881-90. [PMID: 17334654 DOI: 10.1007/s00125-006-0543-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 10/14/2006] [Indexed: 01/14/2023]
Abstract
AIMS/HYPOTHESIS Diabetes accelerates the development of atherosclerosis, which critically involves the proliferation of vascular smooth muscle cells (SMCs). However, how high glucose treatment regulates SMC proliferation is controversial. Considering the established SMC heterogeneity, we hypothesised that glucose treatment may have distinct effects on proliferation of the various phenotypic SMCs. MATERIALS AND METHODS We tested this possibility using cloned spindle-shaped and epithelioid SMCs and laser scanning cytometry. RESULTS Our results showed that glucose treatment significantly inhibited the serum-independent proliferation of epithelioid SMCs, but had no effect on the proliferation of spindle-shaped cells either with or without serum stimulation. Furthermore, glucose treatment inhibited DNA synthesis, as detected by bromodeoxyuridine (BrdU) incorporation, and increased the production of reactive oxygen species in epithelioid SMCs. The inhibition of BrdU incorporation by glucose treatment was mimicked by glucosamine and phorbol 2,13-dibutyrate, a protein kinase C (PKC) activator, and reversed by azaserine, an inhibitor of the hexosamine pathway. In addition, the inhibitory effects of glucose treatment were blocked by GF 109203X (a PKC inhibitor) and PD98058 (a MAPK/ERK kinase, MEK inhibitor), and by knockdown of MEK1 by small interfering RNA (siRNA). The addition of either GF 109203X or PD98058 also reduced the phosphorylation of MAP kinase induced by glucose treatment. CONCLUSIONS/INTERPRETATION Glucose treatment inhibits the proliferation of epithelioid, but not spindle-shaped, vascular SMCs through the activation of PKC and the MAP kinase pathway, suggesting that the effects of hyperglycaemia on vascular disease depend on the phenotype of SMCs involved.
Collapse
Affiliation(s)
- X-L Zheng
- Smooth Muscle Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary Health Sciences Centre, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | | | | |
Collapse
|
13
|
Corteling RL, Brett SE, Yin H, Zheng XL, Walsh MP, Welsh DG. The functional consequence of RhoA knockdown by RNA interference in rat cerebral arteries. Am J Physiol Heart Circ Physiol 2007; 293:H440-7. [PMID: 17369454 DOI: 10.1152/ajpheart.01374.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Uridine triphosphate (UTP) constricts cerebral arteries by activating transduction pathways that increase cytosolic [Ca(2+)] and myofilament Ca(2+) sensitivity. The signaling proteins that comprise these pathways remain uncertain with recent studies implicating a role for several G proteins. To start clarifying which G proteins enable UTP-induced vasoconstriction, a small interfering RNA (siRNA) approach was developed to knock down specified targets in rat cerebral arteries. siRNA directed against G(q) and RhoA was introduced into isolated cerebral arteries using reverse permeabilization. Following a defined period of organ culture, arteries were assayed for contractile function, mRNA levels, and protein expression. Targeted siRNA reduced RhoA or G(q) mRNA expression by 60-70%, which correlated with a reduction in RhoA but not G(q) protein expression. UTP-induced constriction was abolished in RhoA-depleted arteries, but this was not due to a reduction in myosin light chain phosphorylation. UTP-induced actin polymerization was attenuated in RhoA-depleted arteries, which would explain the loss of agonist-induced constriction. In summary, this study illustrates that siRNA approaches can be effectively used on intact arteries to induce targeted knockdown given that the protein turnover rate is sufficiently high. It also demonstrates that the principal role of RhoA in agonist-induced constriction is to facilitate the formation of F-actin, the physical structure to which phosphorylated myosin binds to elicit arterial constriction.
Collapse
Affiliation(s)
- Randolph L Corteling
- Department of Physiology and Biophysics, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada
| | | | | | | | | | | |
Collapse
|
14
|
Gui Y, Yin H, He JY, Yang SH, Walsh MP, Zheng XL. Endoreduplication of human smooth muscle cells induced by 2-methoxyestradiol: a role for cyclin-dependent kinase 2. Am J Physiol Heart Circ Physiol 2007; 292:H1313-20. [PMID: 17056669 DOI: 10.1152/ajpheart.00867.2006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Endoreduplication has been suggested to contribute to the development of hypertrophy of smooth muscle cells (SMCs) in hypertension. However, endoreduplication in vascular SMCs and the underlying molecular mechanisms are not clear. Treatment of human SMCs with 10 μM 2-methoxyestradiol (2-ME) for 24 h induces accumulation of cells with ≥4N DNA content, and some polyploid/aneuploid cells actively synthesize their DNA, suggesting the occurrence of endoreduplication. In addition, 2-ME treatment upregulates the expression of cyclin-dependent kinase 2 (Cdk2). The present study was designed to characterize endoreduplication of human SMCs and explore the potential roles of Cdk2 in endoreduplication induced by 2-ME. Treatment with 2-ME (10 μM) for 2–4 days not only caused increases in >4N cells and their reentry into S phase but also induced overduplication of chromosomes. Furthermore, 2-ME increased the kinase activity of Cdk2 and its interaction with cyclin E. Inducible overexpression of dominant-negative Cdk2 in human SMCs inhibited both DNA synthesis of >4N cells and the accumulation of >4N cells induced by 2-ME. We conclude that 2-ME induces endoreduplication of human SMCs and Cdk2 plays an important role in endoreduplication in response to 2-ME.
Collapse
Affiliation(s)
- Yu Gui
- Smooth Muscle Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, Univ of Calgary, Calgary, Alberta, Canada
| | | | | | | | | | | |
Collapse
|
15
|
Birbes H, Zeiller C, Komati H, Némoz G, Lagarde M, Prigent AF. Phospholipase D protects ECV304 cells against TNFα-induced apoptosis. FEBS Lett 2006; 580:6224-32. [PMID: 17069807 DOI: 10.1016/j.febslet.2006.10.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 10/04/2006] [Accepted: 10/09/2006] [Indexed: 10/24/2022]
Abstract
Tumor necrosis factor alpha (TNFalpha), a pleiotropic cytokine, activates both apoptotic and pro-survival signals depending on the cell model. Using ECV304 cells, which can be made TNFalpha-sensitive by cycloheximide (CHX) co-treatment, we evaluated the potential roles of ceramide and phospholipase D (PLD) in TNFalpha-induced apoptosis. TNFalpha/CHX induced a robust increase in ceramide levels after 16 h of treatment when cell death was maximal. PLD activity was increased at early time point (1h) whereas both PLD activity and PLD1 protein were strongly decreased after 24h. TNFalpha/CHX-induced cell death was significantly lowered by exogenous bacterial PLD and phoshatidic acid, and in cells overexpressing PLD1. Conversely, cells depleted in PLD proteins by small interference RNA (siRNA) treatment exhibited higher susceptibility to apoptosis. These results show that PLD exerts a protective role against TNFalpha-induced cell death.
Collapse
Affiliation(s)
- Helene Birbes
- INSERM U585 and INSA-Lyon and IMBL, Bldg Louis Pasteur,11 avenue Jean Capelle, F-69621 Villeurbanne Cedex, France
| | | | | | | | | | | |
Collapse
|
16
|
Carta S, Tassi S, Semino C, Fossati G, Mascagni P, Dinarello CA, Rubartelli A. Histone deacetylase inhibitors prevent exocytosis of interleukin-1beta-containing secretory lysosomes: role of microtubules. Blood 2006; 108:1618-26. [PMID: 16684958 PMCID: PMC1895509 DOI: 10.1182/blood-2006-03-014126] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A number of agents reducing interleukin-1beta (IL-1beta) activity are being developed as novel immunomodulatory and anti-inflammatory therapies. However, the elucidation of their molecular mechanism of action is required in the context of medical management of inflammatory diseases. Inhibitors of histone deacetylases (HDACs) are promising anticancer agents with pleiotropic activities. Of these, suberoylanilide hydroxamic acid has been reported to inhibit the production of several proinflammatory cytokines. In the present study, we investigated the effects of 2 HDAC inhibitors on IL-1beta secretion: suberoylanilide hydroxamic acid and a newly developed hydroxamic acid-derived compound ITF2357. These HDAC inhibitors do not affect the synthesis or intracellular localization of IL-1beta but both strongly reduce the levels of extracellular IL-1beta by preventing the exocytosis of IL-1beta-containing secretory lysosomes. At nanomolar concentrations, ITF2357 reduces the secretion of IL-1beta following ATP activation of the P2X7 receptor. Whereas the inhibition of HDACs results in hyperacetylation of tubulin, acetylation of HSP90 was unaffected. The reduction in IL-1beta secretion appears to be due to disruption of microtubules impairing lysosome exocytosis. Together, these observations indicate that a functional microtubule network is required for IL-1beta secretion and suggest that disruption of tubulin is the mechanism by which inhibitors of HDACs reduce the secretion of IL-1beta.
Collapse
Affiliation(s)
- Sonia Carta
- Laboratory of Experimental Oncology E, National Cancer Research Institute, Genoa, Italy
| | | | | | | | | | | | | |
Collapse
|
17
|
Gui Y, Zheng XL. 2-Methoxyestradiol Induces Cell Cycle Arrest and Mitotic Cell Apoptosis in Human Vascular Smooth Muscle Cells. Hypertension 2006; 47:271-80. [PMID: 16380515 DOI: 10.1161/01.hyp.0000199656.99448.dc] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It has been shown that 2-methoxyestradiol (2-ME) inhibits cell proliferation and DNA synthesis in human aortic smooth muscle cells. However, the cellular mechanisms underlying the antiproliferative activity of 2-ME are unclear. The present study was performed to explore the cellular mechanisms whereby 2-ME leads to growth inhibition and apoptosis of human smooth muscle cells. Our results demonstrate that at 1 hour of treatment, 1 micromol/L 2-ME induces multiple spindles, overamplified centrosomes, and multipolar cytokinesis, whereas 10 micromol/L 2-ME causes completely damaged spindle, disorientated centrosomes, and missegregated chromosomes. At 6 hours of treatment, the mitotic index was increased and reached a maximal level, and cells with 4N DNA content (4N cells) began to accumulate. The increased mitotic cells induced by 2-ME were apoptotic as detected by both annexin V and TUNEL staining. Blockage of cells in G(1/0) phase by thymidine prevented 2-ME-induced apoptosis. In addition, the increased mitotic index declined concurrently when even more 4N cells accumulated at 12 to 48 hours of treatment with 10 micromol/L 2-ME. Furthermore, in response to 2-ME, cells delayed entry into the next cell cycle and exhibited aneuploidy or micronuclei. Some aneuploidy cells continued to synthesize DNA. We conclude that 2-ME treatment not only arrests cells in mitosis and promotes mitotic cell apoptosis, but also causes cells to undergo "mitotic slippage" and endoreduplication. The induction of mitotic cell arrest and apoptosis may be a major cellular mechanism by which 2-ME inhibits proliferation of human smooth muscle cells.
Collapse
Affiliation(s)
- Yu Gui
- The Smooth Muscle Research Group, Department of Biochemistry and Molecular Biology, The University of Calgary, Alberta, Canada
| | | |
Collapse
|
18
|
Fuchs D, Erhard P, Rimbach G, Daniel H, Wenzel U. Genistein blocks homocysteine-induced alterations in the proteome of human endothelial cells. Proteomics 2005; 5:2808-18. [PMID: 15952232 DOI: 10.1002/pmic.200401174] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Dietary isoflavones from soy are suggested to protect endothelial cells from damaging effects of endothelial stressors and thereby to prevent atherosclerosis. In search of the molecular targets of isoflavone action, we analyzed the effects of the major soy isoflavone, genistein, on changes in protein expression levels induced by the endothelial stressor homocysteine (Hcy) in EA.hy 926 endothelial cells. Proteins from cells exposed for 24 h to 25 microM Hcy alone or in combination with 2.5 microM genistein were separated by two-dimensional gel electrophoresis and those with altered spot intensities were identified by peptide mass fingerprinting. Genistein reversed Hcy-induced changes of proteins involved in metabolism, detoxification, and gene regulation; and some of those effects can be linked functionally to the antiatherosclerotic properties of the soy isoflavone. Alterations of steady-state levels of cytoskeletal proteins by genistein suggested an effect on apoptosis. As a matter of fact genistein caused inhibition of Hcy-mediated apoptotic cell death as indicated by inhibition of DNA fragmentation and chromatin condensation. In conclusion, proteome analysis allows the rapid identification of cellular target proteins of genistein action in endothelial cells exposed to the endothelial stressor Hcy and therefore enables the identification of molecular pathways of its antiatherosclerotic action.
Collapse
Affiliation(s)
- Dagmar Fuchs
- Department of Food and Nutrition, Molecular Nutrition Unit, Technical University of Munich, Freising, Germany
| | | | | | | | | |
Collapse
|
19
|
Puljak L, Pagliassotti MJ, Wei Y, Qadri I, Parameswara V, Esser V, Fitz JG, Kilic G. Inhibition of cellular responses to insulin in a rat liver cell line. A role for PKC in insulin resistance. J Physiol 2005; 563:471-82. [PMID: 15649984 PMCID: PMC1665596 DOI: 10.1113/jphysiol.2004.080333] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The initial response of liver cells to insulin is mediated through exocytosis of Cl- channel-containing vesicles and a subsequent opening of plasma membrane Cl- channels. Intracellular accumulation of fatty acids leads to profound defects in metabolism, and is closely associated with insulin resistance. It is not known whether the activity of Cl- channels is altered in insulin resistance and by which mechanisms. We studied the effects of fatty acid accumulation on Cl- channel opening in a model liver cell line. Overnight treatment with amiodarone increased the fat content by approximately 2-fold, and the rates of gluconeogenesis by approximately 5-fold. The ability of insulin to suppress gluconeogenesis was markedly reduced indicating that amiodarone treatment induces insulin resistance. Western blot analysis showed that these cells express the same number of insulin receptors as control cells. However, insulin failed to activate exocytosis and Cl- channel opening. These inhibitory effects were mimicked in control cells by exposures to arachidonic acid (15 microm). Further studies demonstrated that fatty acids stimulate the PKC activity, and inhibition of PKC partially restored exocytosis and Cl- channel opening in insulin-resistant cells. Accordingly, activation of PKC with PMA in control cells potently inhibited the insulin responses. These results suggest that stimulation of PKC activity in insulin resistance contributes to the inhibition of cellular responses to insulin in liver cells.
Collapse
Affiliation(s)
- Livia Puljak
- Department of Internal Medicine, University of Texas South-western Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-8887, USA
| | | | | | | | | | | | | | | |
Collapse
|