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Cakir Z, Lord SJ, Zhou Y, Jang GM, Polacco BJ, Eckhardt M, Jimenez-Morales D, Newton BW, Orr AL, Johnson JR, da Cruz A, Mullins RD, Krogan NJ, Mahley RW, Swaney DL. Quantitative proteomic analysis reveals apoE4-dependent phosphorylation of the actin-regulating protein VASP. Mol Cell Proteomics 2023; 22:100541. [PMID: 37019383 DOI: 10.1016/j.mcpro.2023.100541] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 02/03/2023] [Accepted: 03/24/2023] [Indexed: 04/05/2023] Open
Abstract
Apolipoprotein (apo) E4 is the major genetic risk factor for Alzheimer's Disease (AD). While neurons generally produce a minority of the apoE in the central nervous system, neuronal expression of apoE increases dramatically in response to stress and is sufficient to drive pathology. Currently, the molecular mechanisms of how apoE4 expression may regulate pathology are not fully understood. Here we expand upon our previous studies measuring the impact of apoE4 on protein abundance to include the analysis of protein phosphorylation and ubiquitylation signaling in isogenic Neuro-2a cells expressing apoE3 or apoE4. ApoE4 expression resulted in a dramatic increase in VASP S235 phosphorylation in a PKA-dependent manner. This phosphorylation disrupted VASP interactions with numerous actin cytoskeletal and microtubular proteins. Reduction of VASP S235 phosphorylation via PKA inhibition resulted in a significant increase in filopodia formation and neurite outgrowth in apoE4-expressing cells, exceeding levels observed in apoE3-expressing cells. Our results highlight the pronounced and diverse impact of apoE4 on multiple modes of protein regulation and identify protein targets to restore apoE4-related cytoskeletal defects.
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Zhu X, Liu H, Deng Z, Yan C, Liu Y, Yin X. Hesperidin Exerts Anxiolytic-like Effects in Rats with Streptozotocin- Induced Diabetes via PKA/CREB Signaling. Curr Mol Pharmacol 2023; 16:91-100. [PMID: 35289260 DOI: 10.2174/1573413718666220314140848] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/16/2021] [Accepted: 12/29/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The mechanisms underlying synaptic injury and anxiety-like behavioral changes caused by diabetes and the strategies to reverse these changes are not well understood. OBJECTIVES This study examined the neuroprotective effects of hesperidin on anxiety-like behaviors in diabetic rats and investigated the underlying mechanisms from the perspective of the PKA/CREB pathway. METHODS Rats with streptozotocin-induced diabetes were treated orally with hesperidin (50 and 150 mg/kg) for 10 weeks. The elevated plus maze (EPM), hole board test (HBT), and marbleburying test (MBT) were used to assess anxiety-like behaviors. We further examined the effects of hesperidin on the PKA/CREB pathway in vivo and in vitro. RESULTS The results show that supplementation with hesperidin exerted anxiolytic effects on the diabetic rats, as evidenced by increased percentages of open arm entries and time spent in the open arms in the EPM; decreased numbers of hole visits in the HBT; decreased numbers of marbles buried; and increased expression of PKA, CREB, BDNF, and synaptic proteins in the amygdala and hippocampus of diabetic rats. Hesperidin was found to reverse the imbalance in the PKA/CREB/BDNF pathway. In vitro, we found that the PKA inhibitor H89 reversed the protective effects of hesperidin against cell injury and reversed the HG-induced expression of PKA, pCREB/CREB, and BDNF. CONCLUSION Our results demonstrated that hesperidin could ameliorate the anxiety-like behaviors of diabetic rats and that activating the PKA/CREB/BDNF pathway contributed to the beneficial effects. This study may provide important insights into the mechanisms underlying anxiety-like behaviors in diabetes and identify new therapeutic targets for clinical treatment.
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Affiliation(s)
- Xia Zhu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Haiyan Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Zongli Deng
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Chuanzhi Yan
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Yaowu Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Xiaoxing Yin
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
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Reversible Platelet Integrin αIIbβ3 Activation and Thrombus Instability. Int J Mol Sci 2022; 23:ijms232012512. [PMID: 36293367 PMCID: PMC9604507 DOI: 10.3390/ijms232012512] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/10/2022] [Accepted: 10/14/2022] [Indexed: 11/28/2022] Open
Abstract
Integrin αIIbβ3 activation is essential for platelet aggregation and, accordingly, for hemostasis and arterial thrombosis. The αIIbβ3 integrin is highly expressed on platelets and requires an activation step for binding to fibrinogen, fibrin or von Willebrand factor (VWF). A current model assumes that the process of integrin activation relies on actomyosin force-dependent molecular changes from a bent-closed and extended-closed to an extended-open conformation. In this paper we review the pathways that point to a functional reversibility of platelet αIIbβ3 activation and transient aggregation. Furthermore, we refer to mouse models indicating that genetic defects that lead to reversible platelet aggregation can also cause instable thrombus formation. We discuss the platelet agonists and signaling pathways that lead to a transient binding of ligands to integrin αIIbβ3. Our analysis points to the (autocrine) ADP P2Y1 and P2Y12 receptor signaling via phosphoinositide 3-kinases and Akt as principal pathways linked to reversible integrin activation. Downstream signaling events by protein kinase C, CalDAG-GEFI and Rap1b have not been linked to transient integrin activation. Insight into the functional reversibility of integrin activation pathways will help to better understand the effects of antiplatelet agents.
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Essential role of aerobic glycolysis in epithelial-to-mesenchymal transition during carcinogenesis. Clin Transl Oncol 2022; 24:1844-1855. [PMID: 35751743 DOI: 10.1007/s12094-022-02851-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 05/02/2022] [Indexed: 10/17/2022]
Abstract
Epithelial-to-mesenchymal transition (EMT) confers the most lethal characteristics to cancer cells i.e., metastasis and resistance to chemo-and-radio-therapy, and therefore exhibit an appealing target in the field of oncology. Research in the past decade has demonstrated the crucial role of aerobic glycolysis in EMT, which is generally credited as the glucose metabolism for the creation of biomass such as fatty acids, amino acids, and nucleotides thereby providing building blocks for limitless proliferation. In the present review, apart from discussing EMT's evident role in the metastatic process and cancer stemness, we also talked about the vital role of glycolytic enzymes viz. GLUTs, HKs, PGI, PFK-1, aldolase, enolase, PK, LDHA, etc. in the induction of the EMT process in cancerous cells.
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Augustin V, Kins S. Fe65: A Scaffolding Protein of Actin Regulators. Cells 2021; 10:cells10071599. [PMID: 34202290 PMCID: PMC8304848 DOI: 10.3390/cells10071599] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 01/19/2023] Open
Abstract
The scaffolding protein family Fe65, composed of Fe65, Fe65L1, and Fe65L2, was identified as an interaction partner of the amyloid precursor protein (APP), which plays a key function in Alzheimer’s disease. All three Fe65 family members possess three highly conserved interaction domains, forming complexes with diverse binding partners that can be assigned to different cellular functions, such as transactivation of genes in the nucleus, modulation of calcium homeostasis and lipid metabolism, and regulation of the actin cytoskeleton. In this article, we rule out putative new intracellular signaling mechanisms of the APP-interacting protein Fe65 in the regulation of actin cytoskeleton dynamics in the context of various neuronal functions, such as cell migration, neurite outgrowth, and synaptic plasticity.
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6
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Synergy and allostery in ligand binding by HIV-1 Nef. Biochem J 2021; 478:1525-1545. [PMID: 33787846 PMCID: PMC8079166 DOI: 10.1042/bcj20201002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 11/27/2022]
Abstract
The Nef protein of human and simian immunodeficiency viruses boosts viral pathogenicity through its interactions with host cell proteins. By combining the polyvalency of its large unstructured regions with the binding selectivity and strength of its folded core domain, Nef can associate with many different host cell proteins, thereby disrupting their functions. For example, the combination of a linear proline-rich motif and hydrophobic core domain surface allows Nef to bind tightly and specifically to SH3 domains of Src family kinases. We investigated whether the interplay between Nef's flexible regions and its core domain could allosterically influence ligand selection. We found that the flexible regions can associate with the core domain in different ways, producing distinct conformational states that alter the way in which Nef selects for SH3 domains and exposes some of its binding motifs. The ensuing crosstalk between ligands might promote functionally coherent Nef-bound protein ensembles by synergizing certain subsets of ligands while excluding others. We also combined proteomic and bioinformatics analyses to identify human proteins that select SH3 domains in the same way as Nef. We found that only 3% of clones from a whole-human fetal library displayed Nef-like SH3 selectivity. However, in most cases, this selectivity appears to be achieved by a canonical linear interaction rather than by a Nef-like ‘tertiary' interaction. Our analysis supports the contention that Nef's mode of hijacking SH3 domains is a virus-specific adaptation with no or very few cellular counterparts. Thus, the Nef tertiary binding surface is a promising virus-specific drug target.
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Klingler P, Niklaus M, Koessler J, Weber K, Koessler A, Boeck M, Kobsar A. Influence of long-term proteasome inhibition on platelet responsiveness mediated by bortezomib. Vascul Pharmacol 2021; 138:106830. [PMID: 33422688 DOI: 10.1016/j.vph.2021.106830] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/28/2020] [Accepted: 01/04/2021] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Although platelets contain a full proteasome system, its role in platelet function is not completely understood yet. Since the proteasome system may be involved in time-delayed processes, platelet responsiveness was investigated after long-term, bortezomib-mediated proteasome inhibition. MATERIALS AND METHODS Citrate-anticoagulated whole blood was stored with 5 nM and 1 μM bortezomib for 24 h. Consecutively, aggregation was measured by light transmission in platelet-rich-plasma (PRP). Flow cytometry was performed to determine phosphorylation levels of the vasodilator-stimulated phosphoprotein (VASP), fibrinogen binding, PAC1-antibody binding and purinergic receptor expression in PRP, P2Y12 activity or glycoprotein (GP) Ib and IIb expression in whole blood. P2Y1 and P2X1 activities were assessed by calcium flux-induced fluorescence in washed platelets. Using PRP, adherent platelets on fibrinogen-, collagen- and ristocetin-coated surfaces were visualized and quantified by immunostaining. RESULTS Under bortezomib, VASP phosphorylation was less inducible and nitric oxide-induced inhibition of fibrinogen binding was slightly reduced. Proteasome inhibition did not tamper adenosine diphosphate-mediated aggregation or purinergic receptor expression and activity. Induced expression of activated fibrinogen receptors and fibrinogen binding were not significantly influenced by incubation with bortezomib for 24 h. Aggregation values with threshold agonist concentrations were increased under bortezomib. Despite unchanged GPIb expression, bortezomib-treated platelets showed enhanced adhesion on coated surfaces. CONCLUSIONS In platelets incubated for 24 h, bortezomib mediates a slight attenuation of inhibitory signaling, associated with facilitated platelet aggregation using threshold agonist concentrations and enhanced adhesion on agonist-coated surfaces.
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Affiliation(s)
- Philipp Klingler
- Institute of Transfusion Medicine and Haemotherapy, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
| | - Marius Niklaus
- Institute of Transfusion Medicine and Haemotherapy, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
| | - Juergen Koessler
- Institute of Transfusion Medicine and Haemotherapy, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
| | - Katja Weber
- Institute of Transfusion Medicine and Haemotherapy, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
| | - Angela Koessler
- Institute of Transfusion Medicine and Haemotherapy, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
| | - Markus Boeck
- Institute of Transfusion Medicine and Haemotherapy, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
| | - Anna Kobsar
- Institute of Transfusion Medicine and Haemotherapy, University of Wuerzburg, Oberduerrbacher Straße 6, D-97080 Wuerzburg, Germany.
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Ahuja N, Ashok C, Natua S, Pant D, Cherian A, Pandkar MR, Yadav P, Vishnu NSS, Mishra J, Samaiya A, Shukla S. Hypoxia-induced TGF-β-RBFOX2-ESRP1 axis regulates human MENA alternative splicing and promotes EMT in breast cancer. NAR Cancer 2020; 2:zcaa021. [PMID: 33089214 PMCID: PMC7116222 DOI: 10.1093/narcan/zcaa021] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hypoxic microenvironment heralds epithelial-mesenchymal transition (EMT), invasion and metastasis in solid tumors. Deregulation of alternative splicing (AS) of several cancer-associated genes has been instrumental in hypoxia-induced EMT. Our study in breast cancer unveils a previously unreported mechanism underlying hypoxia-mediated AS of hMENA, a crucial cytoskeleton remodeler during EMT. We report that the hypoxia-driven depletion of splicing regulator ESRP1 leads to skipping of hMENA exon 11a producing a pro-metastatic isoform, hMENAΔ11a. The transcriptional repression of ESRP1 is mediated by SLUG, which gets stimulated via hypoxia-driven TGF-β signaling. Interestingly, RBFOX2, an otherwise RNA-binding protein, is also found to transcriptionally repress ESRP1 while interacting with SLUG. Similar to SLUG, RBFOX2 gets upregulated under hypoxia via TGF-β signaling. Notably, we found that the exosomal delivery of TGF-β contributes to the elevation of TGF-β signaling under hypoxia. Moreover, our results show that in addition to hMENA, hypoxia-induced TGF-β signaling contributes to global changes in AS of genes associated with EMT. Overall, our findings reveal a new paradigm of hypoxia-driven AS regulation of hMENA and insinuate important implications in therapeutics targeting EMT.
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Affiliation(s)
- Neha Ahuja
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Cheemala Ashok
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Subhashis Natua
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Deepak Pant
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Anna Cherian
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Madhura R Pandkar
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Pooja Yadav
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Narayanan S S Vishnu
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Jharna Mishra
- Department of Pathology, Bansal Hospital, Bhopal, Madhya Pradesh 462016, India
| | - Atul Samaiya
- Department of Surgical Oncology, Bansal Hospital, Bhopal, Madhya Pradesh 462016, India
| | - Sanjeev Shukla
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
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The Cell Cycle Checkpoint System MAST(L)-ENSA/ARPP19-PP2A is Targeted by cAMP/PKA and cGMP/PKG in Anucleate Human Platelets. Cells 2020; 9:cells9020472. [PMID: 32085646 PMCID: PMC7072724 DOI: 10.3390/cells9020472] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/14/2020] [Accepted: 02/14/2020] [Indexed: 12/13/2022] Open
Abstract
The cell cycle is controlled by microtubule-associated serine/threonine kinase-like (MASTL), which phosphorylates the cAMP-regulated phosphoproteins 19 (ARPP19) at S62 and 19e/α-endosulfine (ENSA) at S67and converts them into protein phosphatase 2A (PP2A) inhibitors. Based on initial proteomic data, we hypothesized that the MASTL-ENSA/ARPP19-PP2A pathway, unknown until now in platelets, is regulated and functional in these anucleate cells. We detected ENSA, ARPP19 and various PP2A subunits (including seven different PP2A B-subunits) in proteomic studies of human platelets. ENSA-S109/ARPP19–S104 were efficiently phosphorylated in platelets treated with cAMP- (iloprost) and cGMP-elevating (NO donors/riociguat) agents. ENSA-S67/ARPP19-S62 phosphorylations increased following PP2A inhibition by okadaic acid (OA) in intact and lysed platelets indicating the presence of MASTL or a related protein kinase in human platelets. These data were validated with recombinant ENSA/ARPP19 and phospho-mutants using recombinant MASTL, protein kinase A and G. Both ARPP19 phosphorylation sites S62/S104 were dephosphorylated by platelet PP2A, but only S62-phosphorylated ARPP19 acted as PP2A inhibitor. Low-dose OA treatment of platelets caused PP2A inhibition, diminished thrombin-stimulated platelet aggregation and increased phosphorylation of distinct sites of VASP, Akt, p38 and ERK1/2 MAP kinases. In summary, our data establish the entire MASTL(like)–ENSA/ARPP19–PP2A pathway in human platelets and important interactions with the PKA, MAPK and PI3K/Akt systems.
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10
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Nam GS, Lee KS, Nam KS. Anti‑platelet activity of mineral‑balanced deep sea water is mediated via the regulation of Akt and ERK pathway crosstalk. Int J Mol Med 2020; 45:658-668. [PMID: 31894254 DOI: 10.3892/ijmm.2019.4424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 11/14/2019] [Indexed: 11/06/2022] Open
Abstract
Mineral‑balanced deep sea water (MBDSW), an unlimited natural sea source, has been demonstrated to minimize the risk of developing cardiovascular diseases, such as obesity, hypertension, inflammation and hyperlipidemia. This study investigated the effects of MBDSW [magnesium (Mg):calcium (Ca) ratio, 3:1] on platelet activation. MBDSW significantly inhibited the collagen‑ and thrombin‑induced platelet aggregation of human platelets. In collagen‑induced platelets, MBDSW inhibited intracellular calcium mobilization, granule secretion [serotonin, adenosine triphosphate (ATP) and P‑selectin expression] and thromboxane A2 (TXA2) production. Moreover, MBDSW markedly inhibited Akt and extracellular signal‑regulated kinase (ERK) phosphorylation, but not that of c‑Jun N‑terminal kinase (JNK) and p38. Moreover, MBDSW phosphorylated inositol 1,4,5‑triphosphate receptor (IP3R) and vasodilator‑stimulated phosphoprotein (VASP), and it increased the cyclic adenosine monophosphate (cAMP) level in collagen‑induced human platelets. Dipyridamole, a phosphodiesterase (PDE) inhibitor, significantly increased the cAMP level and regulated the Akt, ERK and VASP (Ser157) levels in a manner similar to that of MBDSW. In addition, LY294002, an Akt inhibitor, inhibited the phosphorylation of ERK, and U0126, an ERK inhibitor, inhibited the phosphorylation of Akt. Taken together, the results of the present investigation suggest that the inhibitory effects of MBDSW on platelet aggregation may be associated with the cross‑inhibition of Akt and ERK phosphorylation. These results strongly indicate that MBDSW may have preventive or therapeutic potential for platelet aggregation‑mediated diseases, such as thrombosis, atherosclerosis and myocardial infarction.
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Affiliation(s)
- Gi Suk Nam
- Department of Pharmacology and Intractable Disease Research Center, School of Medicine, Dongguk University, Gyeongju, Gyeongsangbuk‑do 38066, Republic of Korea
| | - Kyu-Shik Lee
- Department of Pharmacology and Intractable Disease Research Center, School of Medicine, Dongguk University, Gyeongju, Gyeongsangbuk‑do 38066, Republic of Korea
| | - Kyung-Soo Nam
- Department of Pharmacology and Intractable Disease Research Center, School of Medicine, Dongguk University, Gyeongju, Gyeongsangbuk‑do 38066, Republic of Korea
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11
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Clifton NE, Trent S, Thomas KL, Hall J. Regulation and Function of Activity-Dependent Homer in Synaptic Plasticity. MOLECULAR NEUROPSYCHIATRY 2019; 5:147-161. [PMID: 31312636 DOI: 10.1159/000500267] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/09/2019] [Indexed: 12/22/2022]
Abstract
Alterations in synaptic signaling and plasticity occur during the refinement of neural circuits over the course of development and the adult processes of learning and memory. Synaptic plasticity requires the rearrangement of protein complexes in the postsynaptic density (PSD), trafficking of receptors and ion channels and the synthesis of new proteins. Activity-induced short Homer proteins, Homer1a and Ania-3, are recruited to active excitatory synapses, where they act as dominant negative regulators of constitutively expressed, longer Homer isoforms. The expression of Homer1a and Ania-3 initiates critical processes of PSD remodeling, the modulation of glutamate receptor-mediated functions, and the regulation of calcium signaling. Together, available data support the view that Homer1a and Ania-3 are responsible for the selective, transient destabilization of postsynaptic signaling complexes to facilitate plasticity of the excitatory synapse. The interruption of activity-dependent Homer proteins disrupts disease-relevant processes and leads to memory impairments, reflecting their likely contribution to neurological disorders.
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Affiliation(s)
- Nicholas E Clifton
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom.,MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
| | - Simon Trent
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Kerrie L Thomas
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom.,School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Jeremy Hall
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom.,MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
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12
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Kameritsch P, Kiemer F, Mannell H, Beck H, Pohl U, Pogoda K. PKA negatively modulates the migration enhancing effect of Connexin 43. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:828-838. [PMID: 30769008 DOI: 10.1016/j.bbamcr.2019.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 12/22/2022]
Abstract
Connexin 43 (Cx43) expression is associated with an increased cell migration and related changes of the actin cytoskeleton (enhanced filopodia formation). These effects are mediated by the C-terminal cytoplasmic part of Cx43 in a channel-independent manner. Since this part has been shown to interact with a variety of proteins and has multiple phosphorylation sites we analyzed here a potential role of the protein kinase A (PKA) for the Cx43 mediated increase in cell migration. Mutation of the PKA-phosphorylation site (substitution of three serines by alanine or glycine) resulted in a further increase in cell motility compared to wild-type Cx43, but with a loss of directionality. Likewise, cell motility was enhanced by PKA inhibition only in Cx43 expressing cells, while reduced in the presence of the PKA activator forskolin. In contrast, cell motility remained unaffected by stimulation with forskolin in cells expressing Cx43 with the mutated PKA phosphorylation site (Cx43-PKA) as well as in Cx-deficient cells. Moreover, PKA activation resulted in increased binding of PKA and VASP to Cx43 associated with an enhanced phosphorylation of VASP, an important regulatory protein of cell polarity and directed migration. Functionally, we could confirm these results in endothelial cells endogenously expressing Cx43. A Tat-Cx43 peptide containing the PKA phosphorylation site abolished the PKA dependent reduction in endothelial cell migration. Our results indicate that PKA dependent phosphorylation of Cx43 modulates cell motility and plays a pivotal role in regulating directed cell migration.
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Affiliation(s)
- Petra Kameritsch
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Biedersteiner Str. 29, 80802 München, Germany.
| | - Felizitas Kiemer
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany.
| | - Hanna Mannell
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany.
| | - Heike Beck
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany.
| | - Ulrich Pohl
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Biedersteiner Str. 29, 80802 München, Germany; Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Str. 17, 81377 München, Germany.
| | - Kristin Pogoda
- Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München and Munich University Hospital, Großhaderner Str. 9, 82152 Planegg, Martinsried, Germany; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Biedersteiner Str. 29, 80802 München, Germany.
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13
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Özakca I, Özçelikay AT. Chronic inhibition of nitric oxide synthase modulates calcium handling in rat heart 1. Can J Physiol Pharmacol 2018; 97:313-319. [PMID: 30388373 DOI: 10.1139/cjpp-2018-0388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Systemic infusion of nitric oxide synthase (NOS) inhibitors increases peripheral vascular resistance due to inhibition of endothelial NOS leading to the activation of the arterial baroreceptor mechanisms and inhibition of central sympathetic outflow. In the current study, we explored that systemic NOS blockage activates protein kinase A (PKA)-mediated signaling pathway through maintained cGMP-dependent protein kinase (PKG) activation. Rats were treated with 3 different concentrations of N(ω)-nitro-l-arginine methyl ester (L-NAME) for 14 days. Systemic L-NAME treatment induced a dose-dependent increase in blood pressure and increased mRNA levels of atrial natriuretic peptide (ANP) and phosphorylation levels of p44/42 MAPK without any change in cardiac mass. The cardiac cGMP levels and PKG-mediated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) (Ser239) did not alter in any group. At the highest dose of treatment (100 mg/kg per day), PKA-mediated phosphorylations of VASP (Ser157) and troponin I (TnI) (Ser23/24) were enhanced significantly indicating the increase in PKA activation in response to chronic NOS blockage. Alterations in both phosphorylated phospholamban (Ser16/Thr17) and sarcoplasmic/endoplasmic Ca2+-ATPase (SERCA2) levels can increase cytosolic Ca2+ load and impair Ca2+ handling. Our data suggest that the increased PKA activation in response to chronic NOS blockage appears to be responsible for cardiac abnormalities that occur due to prolonged L-NAME treatment.
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Affiliation(s)
- Işıl Özakca
- Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey.,Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - A Tanju Özçelikay
- Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey.,Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Turkey
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14
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Choi S, Park M, Kim J, Park W, Kim S, Lee DK, Hwang JY, Choe J, Won MH, Ryoo S, Ha KS, Kwon YG, Kim YM. TNF-α elicits phenotypic and functional alterations of vascular smooth muscle cells by miR-155-5p-dependent down-regulation of cGMP-dependent kinase 1. J Biol Chem 2018; 293:14812-14822. [PMID: 30104414 DOI: 10.1074/jbc.ra118.004220] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 08/02/2018] [Indexed: 12/20/2022] Open
Abstract
cGMP-dependent protein kinase 1 (PKG1) plays an important role in nitric oxide (NO)/cGMP-mediated maintenance of vascular smooth muscle cell (VSMC) phenotype and vasorelaxation. Inflammatory cytokines, including tumor necrosis factor-α (TNFα), have long been understood to mediate several inflammatory vascular diseases. However, the underlying mechanism of TNFα-dependent inflammatory vascular disease is unclear. Here, we found that TNFα treatment decreased PKG1 expression in cultured VSMCs, which correlated with NF-κB-dependent biogenesis of miR-155-5p that targeted the 3'-UTR of PKG1 mRNA. TNFα induced VSMC phenotypic switching from a contractile to a synthetic state through the down-regulation of VSMC marker genes, suppression of actin polymerization, alteration of cell morphology, and elevation of cell proliferation and migration. All of these events were blocked by treatment with an inhibitor of miR-155-5p or PKG1, whereas transfection with miR-155-5p mimic or PKG1 siRNA promoted phenotypic modulation, similar to the response to TNFα. In addition, TNFα-induced miR-155-5p inhibited the vasorelaxant response of de-endothelialized mouse aortic vessels to 8-Br-cGMP by suppressing phosphorylation of myosin phosphatase and myosin light chain, both of which are downstream signal modulators of PKG1. Moreover, TNFα-induced VSMC phenotypic alteration and vasodilatory dysfunction were blocked by NF-κB inhibition. These results suggest that TNFα impairs NO/cGMP-mediated maintenance of the VSMC contractile phenotype and vascular relaxation by down-regulating PKG1 through NF-κB-dependent biogenesis of miR-155-5p. Thus, the NF-κB/miR-155-5p/PKG1 axis may be crucial in the pathogenesis of inflammatory vascular diseases, such as atherosclerotic intimal hyperplasia and preeclamptic hypertension.
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Affiliation(s)
- Seunghwan Choi
- From the Departments of Molecular and Cellular Biochemistry
| | - Minsik Park
- From the Departments of Molecular and Cellular Biochemistry
| | - Joohwan Kim
- From the Departments of Molecular and Cellular Biochemistry
| | - Wonjin Park
- From the Departments of Molecular and Cellular Biochemistry
| | - Suji Kim
- From the Departments of Molecular and Cellular Biochemistry
| | - Dong-Keon Lee
- From the Departments of Molecular and Cellular Biochemistry
| | | | | | - Moo-Ho Won
- Neurobiology, Kangwon National University School of Medicine, Chuncheon, Gangwon-do 24341
| | - Sungwoo Ryoo
- the Department of Biology, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon-do 24341, and
| | - Kwon-Soo Ha
- From the Departments of Molecular and Cellular Biochemistry
| | - Young-Guen Kwon
- the Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, South Korea
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15
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Ali M, Rogers LK, Heyob KM, Buhimschi CS, Buhimschi IA. Changes in Vasodilator-Stimulated Phosphoprotein Phosphorylation, Profilin-1, and Cofilin-1 in Accreta and Protection by DHA. Reprod Sci 2018; 26:757-765. [PMID: 30092744 DOI: 10.1177/1933719118792095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Accreta and gestational trophoblastic disease (ie, choriocarcinoma) are placental pathologies characterized by hyperproliferative and invasive trophoblasts. Cellular proliferation, migration, and invasion are heavily controlled by actin-binding protein (ABP)-mediated actin dynamics. The ABP vasodilator-stimulated phosphoprotein (VASP) carries key regulatory role. Profilin-1, cofilin-1, and VASP phosphorylated at Ser157 (pVASP-S157) and Ser239 (pVASP-S239) are ABPs that regulate actin polymerization and stabilization and facilitate cell metastases. Docosahexaenoic acid (DHA) inhibits cancer cell migration and proliferation. We hypothesized that analogous to malignant cells, ABPs regulate these processes in extravillous trophoblasts (EVTs), which exhibit aberrant expression in placenta accreta. Placental-myometrial junction biopsies of histologically confirmed placenta accreta had significantly increased immunostaining levels of cofilin-1, VASP, pVASP-S239, and F-actin. Treatment of choriocarcinoma-derived trophoblast (BeWo) cells with DHA (30 µM) for 24 hours significantly suppressed proliferation, migration, and pVASP-S239 levels and altered protein profiles consistent with increased apoptosis. We concluded that in accreta changes in the ABP expression profile were a response to restore homeostasis by counteracting the hyperproliferative and invasive phenotype of the EVT. The observed association between VASP phosphorylation, apoptosis, and trophoblast proliferation and migration suggest that DHA may offer a therapeutic solution for conditions where EVT is hyperinvasive.
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Affiliation(s)
- Mehboob Ali
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA.
| | - Lynette K Rogers
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Kathryn M Heyob
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA
| | - Catalin S Buhimschi
- Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Irina A Buhimschi
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, 575 Children's Crossroad, Columbus, OH, 43215, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, The Ohio State University College of Medicine, Columbus, OH, USA
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16
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Tumor suppressor berberine binds VASP to inhibit cell migration in basal-like breast cancer. Oncotarget 2018; 7:45849-45862. [PMID: 27322681 PMCID: PMC5216765 DOI: 10.18632/oncotarget.9968] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 05/29/2016] [Indexed: 12/18/2022] Open
Abstract
Berberine is a plant-derived compound used in traditional Chinese medicine, which has been shown to inhibit cell proliferation and migration in breast cancer. On the other hand, vasodilator-stimulated phosphoprotein (VASP) promotes actin filament elongation and cell migration. We previously showed that VASP is overexpressed in high-motility breast cancer cells. Here we investigated whether the anti-tumorigenic effects of berberine are mediated by binding VASP in basal-like breast cancer. Our results show that berberine suppresses proliferation and migration of MDA-MB-231 cells as well as tumor growth in MDA-MB-231 nude mouse xenografts. We also show that berberine binds to VASP, inducing changes in its secondary structure and inhibits actin polymerization. Our study reveals the mechanism underlying berberine's inhibition of cell proliferation and migration in basal-like breast cancer, highlighting the use of berberine as a potential adjuvant therapeutic agent.
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17
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Radeva MY, Waschke J. Mind the gap: mechanisms regulating the endothelial barrier. Acta Physiol (Oxf) 2018; 222. [PMID: 28231640 DOI: 10.1111/apha.12860] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 11/21/2016] [Accepted: 02/16/2017] [Indexed: 12/11/2022]
Abstract
The endothelial barrier consists of intercellular contacts localized in the cleft between endothelial cells, which is covered by the glycocalyx in a sievelike manner. Both types of barrier-forming junctions, i.e. the adherens junction (AJ) serving mechanical anchorage and mechanotransduction and the tight junction (TJ) sealing the intercellular space to limit paracellular permeability, are tethered to the actin cytoskeleton. Under resting conditions, the endothelium thereby builds a selective layer controlling the exchange of fluid and solutes with the surrounding tissue. However, in the situation of an inflammatory response such as in anaphylaxis or sepsis intercellular contacts disintegrate in post-capillary venules leading to intercellular gap formation. The resulting oedema can cause shock and multi-organ failure. Therefore, maintenance as well as coordinated opening and closure of interendothelial junctions is tightly regulated. The two principle underlying mechanisms comprise spatiotemporal activity control of the small GTPases Rac1 and RhoA and the balance of the phosphorylation state of AJ proteins. In the resting state, junctional Rac1 and RhoA activity is enhanced by junctional components, actin-binding proteins, cAMP signalling and extracellular cues such as sphingosine-1-phosphate (S1P) and angiopoietin-1 (Ang-1). In addition, phosphorylation of AJ components is prevented by junction-associated phosphatases including vascular endothelial protein tyrosine phosphatase (VE-PTP). In contrast, inflammatory mediators inhibiting cAMP/Rac1 signalling cause strong activation of RhoA and induce AJ phosphorylation finally leading to endocytosis and cleavage of VE-cadherin. This results in dissolution of TJs the outcome of which is endothelial barrier breakdown.
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Affiliation(s)
- M. Y. Radeva
- Institute of Anatomy and Cell Biology; Ludwig-Maximilians-Universität München; Munich Germany
| | - J. Waschke
- Institute of Anatomy and Cell Biology; Ludwig-Maximilians-Universität München; Munich Germany
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18
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Derler R, Gesslbauer B, Weber C, Strutzmann E, Miller I, Kungl A. Glycosaminoglycan-Mediated Downstream Signaling of CXCL8 Binding to Endothelial Cells. Int J Mol Sci 2017; 18:ijms18122605. [PMID: 29207576 PMCID: PMC5751208 DOI: 10.3390/ijms18122605] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 11/24/2017] [Accepted: 11/29/2017] [Indexed: 01/13/2023] Open
Abstract
The recruitment of leukocytes, mediated by endothelium bound chemokine gradients, is a vital process in inflammation. The highly negatively charged, unbranched polysaccharide family of glycosaminoglycans (GAGs), such as heparan sulfate and chondroitin sulfate mediate chemokine immobilization. Specifically the binding of CXCL8 (interleukin 8) to GAGs on endothelial cell surfaces is known to regulate neutrophil recruitment. Currently, it is not clear if binding of CXCL8 to GAGs leads to endothelial downstream signaling in addition to the typical CXCR1/CXCR2 (C-X-C motif chemokine receptor 1 and 2)-mediated signaling which activates neutrophils. Here we have investigated the changes in protein expression of human microvascular endothelial cells induced by CXCL8. Tumor necrosis factor alpha (TNFα) stimulation was used to mimic an inflammatory state which allowed us to identify syndecan-4 (SDC4) as the potential proteoglycan co-receptor of CXCL8 by gene array, real-time PCR and flow cytometry experiments. Enzymatic GAG depolymerization via heparinase III and chondroitinase ABC was used to emulate the effect of glycocalyx remodeling on CXCL8-induced endothelial downstream signaling. Proteomic analyses showed changes in the expression pattern of a number of endothelial proteins such as Zyxin and Caldesmon involved in cytoskeletal organization, cell adhesion and cell mobility. These results demonstrate for the first time a potential role of GAG-mediated endothelial downstream signaling in addition to the well-known CXCL8-CXCR1/CXCR2 signaling pathways in neutrophils.
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Affiliation(s)
- Rupert Derler
- Antagonis Biotherapeutics GmbH, Strasserhofweg 77a, 8045 Graz, Austria.
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Schubertstrasse 1, 8010 Graz, Austria.
| | - Bernd Gesslbauer
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Schubertstrasse 1, 8010 Graz, Austria.
| | - Corinna Weber
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Schubertstrasse 1, 8010 Graz, Austria.
| | - Elisabeth Strutzmann
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Schubertstrasse 1, 8010 Graz, Austria.
| | - Ingrid Miller
- Institute for Medical Biochemistry, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria.
| | - Andreas Kungl
- Antagonis Biotherapeutics GmbH, Strasserhofweg 77a, 8045 Graz, Austria.
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Schubertstrasse 1, 8010 Graz, Austria.
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19
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Tanimura S, Takeda K. ERK signalling as a regulator of cell motility. J Biochem 2017; 162:145-154. [PMID: 28903547 DOI: 10.1093/jb/mvx048] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/17/2017] [Indexed: 01/21/2023] Open
Abstract
Cell motility is regulated by multiple processes, including cell protrusion, cell retraction, cell-matrix adhesion, polarized exocytosis and polarized vesicle trafficking, each of which is spatiotemporally controlled by various intracellular signalling pathways. Dysregulation of cell motility leads to pathological conditions, such as tumour invasion and metastasis. Accumulating evidence has revealed that extracellular signal-regulated kinase (ERK) signalling is one of the critical regulators of cell motility, although it is classically known as an important regulator of cell proliferation, differentiation and survival through regulation of gene expression. ERK and its downstream kinase, p90 ribosomal S6 kinase (RSK), dynamically regulate cell motility mainly through direct phosphorylation of various molecules that are not necessarily involved in the regulation of gene transcription and translation. In this review, we summarize how ERK signalling regulates cell motility by focusing on the components of the cell motility machinery that are directly regulated by ERK or RSK.
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Affiliation(s)
- Susumu Tanimura
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Kohsuke Takeda
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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20
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Ngan E, Kiepas A, Brown CM, Siegel PM. Emerging roles for LPP in metastatic cancer progression. J Cell Commun Signal 2017; 12:143-156. [PMID: 29027626 DOI: 10.1007/s12079-017-0415-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/03/2017] [Indexed: 01/21/2023] Open
Abstract
LIM domain containing proteins are important regulators of diverse cellular processes, and play pivotal roles in regulating the actin cytoskeleton. Lipoma Preferred Partner (LPP) is a member of the zyxin family of LIM proteins that has long been characterized as a promoter of mesenchymal/fibroblast cell migration. More recently, LPP has emerged as a critical inducer of tumor cell migration, invasion and metastasis. LPP is thought to contribute to these malignant phenotypes by virtue of its ability to shuttle into the nucleus, localize to adhesions and, most recently, to promote invadopodia formation. In this review, we will examine the mechanisms through which LPP regulates the functions of adhesions and invadopodia, and discuss potential roles of LPP in mediating cellular responses to mechanical cues within these mechanosensory structures.
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Affiliation(s)
- Elaine Ngan
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 508, Montréal, Québec, H3A 1A3, Canada.,Department of Medicine, McGill University, Montréal, Québec, Canada
| | - Alex Kiepas
- Department of Physiology, McGill University, Montréal, Québec, Canada
| | - Claire M Brown
- Department of Physiology, McGill University, Montréal, Québec, Canada
| | - Peter M Siegel
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 508, Montréal, Québec, H3A 1A3, Canada. .,Department of Medicine, McGill University, Montréal, Québec, Canada.
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21
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Drebrin's Role in the Maintenance of Endothelial Integrity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1006:347-360. [PMID: 28865031 DOI: 10.1007/978-4-431-56550-5_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
The human endothelium forms a permeable barrier between the blood stream and surrounding tissues, strictly governing the passage of immune cells, fluids and metabolites. The regulation of cell-cell contact dynamics between endothelial cells is essential for this function and thus for the maintenance of vascular integrity. Intercellular adhesion within the endothelium is mainly dependent on adherens junctions, composed of cell-cell adhesion proteins such as VE-cadherin and nectin, and their associated proteins. Recent research points to a critical role of the actin cytoskeleton in endothelial integrity, by providing anchorage of adhesion complexes to the cell cortex. We could show that the F-actin-binding protein drebrin is a critical regulator of endothelial integrity, by linking nectin to the cortical actin cytoskeleton. In particular, the knockdown of drebrin leads to functional impairment of endothelial cells, characterized by rupturing of endothelial monolayers cultured under conditions mimicking vascular flow. This weakening of cell-cell contacts upon drebrin depletion is based on the destabilization of nectin at adherens junctions, followed by internalization and degradation in lysosomes. Conducting interaction studies, we showed that drebrin binds to nectin's interaction partner afadin, thus linking the nectin/afadin system to the cortical F-actin network. Drebrin, containing binding sites for both afadin and F-actin, is thus uniquely equipped to stabilize nectin at adherens junctions, thereby preserving endothelial integrity. Collectively, these results contribute to the current understanding of cell-cell junction regulation, introducing a new function of drebrin as a stabilizer of endothelial integrity.
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22
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Vaughen J, Igaki T. Slit-Robo Repulsive Signaling Extrudes Tumorigenic Cells from Epithelia. Dev Cell 2017; 39:683-695. [PMID: 27997825 DOI: 10.1016/j.devcel.2016.11.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 10/04/2016] [Accepted: 11/19/2016] [Indexed: 02/08/2023]
Abstract
Cells dynamically interact throughout animal development to coordinate growth and deter disease. For example, cell-cell competition weeds out aberrant cells to enforce homeostasis. In Drosophila, tumorigenic cells mutant for the cell polarity gene scribble (scrib) are actively eliminated from epithelia when surrounded by wild-type cells. While scrib cell elimination depends critically on JNK signaling, JNK-dependent cell death cannot sufficiently explain scrib cell extirpation. Thus, how JNK executed cell elimination remained elusive. Here, we show that repulsive Slit-Robo2-Ena signaling exerts an extrusive force downstream of JNK to eliminate scrib cells from epithelia by disrupting E-cadherin. While loss of Slit-Robo2-Ena in scrib cells potentiates scrib tumor formation within the epithelium, Robo2-Ena hyperactivation surprisingly triggers luminal scrib tumor growth following excess extrusion. This extrusive signaling is amplified by a positive feedback loop between Slit-Robo2-Ena and JNK. Our observations provide a potential causal mechanism for Slit-Robo dysregulation in numerous human cancers.
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Affiliation(s)
- John Vaughen
- Laboratory of Genetics, Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tatsushi Igaki
- Laboratory of Genetics, Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyo-ku, Kyoto 606-8501, Japan.
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23
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24
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Duncan RS, Hwang SY, Koulen P. Effects of Vesl/Homer Proteins on Intracellular Signaling. Exp Biol Med (Maywood) 2016; 230:527-35. [PMID: 16118402 DOI: 10.1177/153537020523000803] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The clustering of signaling molecules at specialized cellular sites allows cells to effectively convert extracellular signals into intracellular signals and to produce a concerted functional output with specific temporal and spatial patterns. A prime example for these molecules and their effects on cellular signaling are the postsynaptic density proteins of the central nervous system. Recently, one group of these proteins, the Vesl/Homer protein family has received increased attention because of its unique molecular properties that allow both the clustering end functional modulation of a plethora of different binding Proteins. Within multlprotein signaling complexes, Vesl/Homer Proteins influence proteins as diverse as metabotropic glutamate receptors; transient receptor potential channels; intracellular calcium channels; the scaffolding protein, Shank; small GTPases; transcription factors; and cytoskeletal proteins. Furthermore, interaction with such functionally relevant proteins also links Vesl/Homer proteins indirectly to an even larger group of cellular effector proteins, putting the Vesl/Homer Proteins at the crossroads of several critical intracellular signaling processes. In addition to the initial reports of Vesl/Homer protein expression in the central nervous system, members of this protein family have now been identified in other excitable cells in various muscle types and in a large number of nonexcitable cells. The widespread expression of Vesl/Homer proteins in different organs and their functional importance in cellular protein signaling complexes is further evidenced by their conservation in organisms from Drosoohila to humans.
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Affiliation(s)
- R Scott Duncan
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Boulevard, Fort Worth, Texas 76107-2699, USA
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25
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Benz PM, Laban H, Zink J, Günther L, Walter U, Gambaryan S, Dib K. Vasodilator-Stimulated Phosphoprotein (VASP)-dependent and -independent pathways regulate thrombin-induced activation of Rap1b in platelets. Cell Commun Signal 2016; 14:21. [PMID: 27620165 PMCID: PMC5020514 DOI: 10.1186/s12964-016-0144-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 09/06/2016] [Indexed: 11/13/2022] Open
Abstract
Background Vasodilator-Stimulated Phosphoprotein (VASP) is involved in the inhibition of agonist-induced platelet aggregation by cyclic nucleotides and the adhesion of platelets to the vascular wall. αIIbβ3 is the main integrin responsible for platelet activation and Rap1b plays a key role in integrin signalling. We investigated whether VASP is involved in the regulation of Rap1b in platelets since VASP-null platelets exhibit augmented adhesion to endothelial cells in vivo. Methods Washed platelets from wild type and VASP-deficient mice were stimulated with thrombin, the purinergic receptors agonist ADP, or the thromboxane A2 receptor agonist U46619 and Rap1b activation was measured using the GST-RalGDS-RBD binding assay. Interaction of VASP and Crkl was investigated by co-immunoprecipitation, confocal microscopy, and pull-down assays using Crkl domains expressed as GST-fusion proteins. Results Surprisingly, we found that activation of Rap1b in response to thrombin, ADP, or U46619 was significantly reduced in platelets from VASP-null mice compared to platelets from wild type mice. However, inhibition of thrombin-induced activation of Rap1b by nitric oxide (NO) was similar in platelets from wild type and VASP-null mice indicating that the NO/cGMP/PKG pathway controls inhibition of Rap1b independently from VASP. To understand how VASP regulated Rap1b, we investigated association between VASP and the Crk-like protein (Crkl), an adapter protein which activates the Rap1b guanine nucleotide exchange factor C3G. We demonstrated the formation of a Crkl/VASP complex by showing that: 1) Crkl co-immunoprecipitated VASP from platelet lysates; 2) Crkl and VASP dynamically co-localized at actin-rich protrusions reminiscent of focal adhesions, filopodia, and lamellipodia upon platelet spreading on fibronectin; 3) recombinant VASP bound directly to the N-terminal SH3 domain of Crkl; 4) Protein Kinase A (PKA) -mediated VASP phosphorylation on Ser157 abrogated the binding of Crkl. Conclusions We identified Crkl as a novel protein interacting with VASP in platelets. We propose that the C3G/Crkl/VASP complex plays a role in the regulation of Rap1b and this explains, at least in part, the reduced agonist-induced activation of Rap1b in VASP-null platelets. In addition, the fact that PKA-dependent VASP phosphorylation abrogated its interaction with Crkl may provide, at least in part, a rationale for the PKA-dependent inhibition of Rap1b and platelet aggregation.
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Affiliation(s)
- Peter M Benz
- Institute for Vascular Signalling, Centre for Molecular Medicine, Johann Wolfgang Goethe University and DZHK (German Centre for Cardiovascular Research) partner site Rhine-Main, 60590, Frankfurt, Germany
| | - Hebatullah Laban
- Institute for Vascular Signalling, Centre for Molecular Medicine, Johann Wolfgang Goethe University and DZHK (German Centre for Cardiovascular Research) partner site Rhine-Main, 60590, Frankfurt, Germany
| | - Joana Zink
- Institute for Vascular Signalling, Centre for Molecular Medicine, Johann Wolfgang Goethe University and DZHK (German Centre for Cardiovascular Research) partner site Rhine-Main, 60590, Frankfurt, Germany
| | - Lea Günther
- Institute for Vascular Signalling, Centre for Molecular Medicine, Johann Wolfgang Goethe University and DZHK (German Centre for Cardiovascular Research) partner site Rhine-Main, 60590, Frankfurt, Germany
| | - Ulrich Walter
- Centre for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Mainz, Germany
| | - Stepan Gambaryan
- Department of Cytology and Histology, St. Petersburg State University, St. Petersburg, Russia.,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Karim Dib
- Centre for Experimental Medicine, Medical Biology Center (MBC) building, Queen's University of Belfast, Third floor, 97 Lisburn Road, BT9 7BL, Belfast, Northern Ireland, UK.
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26
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Kumar A, Dumasia K, Gaonkar R, Sonawane S, Kadam L, Balasinor NH. Estrogen and androgen regulate actin-remodeling and endocytosis-related genes during rat spermiation. Mol Cell Endocrinol 2015; 404:91-101. [PMID: 25637714 DOI: 10.1016/j.mce.2014.12.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/26/2014] [Accepted: 12/17/2014] [Indexed: 12/22/2022]
Abstract
Spermiation, the sperm release process, is imperative to male fertility and reproduction. Morphologically, it is characterized by removal of atypical adherens junctions called ectoplasmic specializations, and formation of transient endocytic devices called tubulobulbar complexes requiring cytoskeleton remodeling and recruitment of proteins needed for endocytosis. Earlier, estrogen administration to adult male rats was seen to cause spermiation failure due to disruption of tubulobulbar complexes. This was accompanied by reduction in intratesticular testosterone levels and increase in intratesticular estrogen along with deregulation of genes involved in cytoskeleton remodeling (Arpc1b, Evl and Capg) and endocytosis (Picalm, Eea1 and Stx5a). In the present study, we aim to understand the role of estrogen and androgen in regulating these genes independently using seminiferous tubule culture system treated with estrogen, androgen or agonists and antagonists of estrogen receptors. We find that transcripts of Arpc1b, Evl and Picalm are responsive to estrogen while those of Picalm, Eea1 and Stx5a are responsive to androgen. We also find that the estrogen regulation of Arpc1b and Evl is mediated through estrogen receptor β and that of Picalm occurs through estrogen receptors α and β. Localization of these proteins at or in the vicinity of tubulobulbar complexes reveals that ARPC1B, EVL, PICALM, EEA1 and STX5A seem to be involved in spermiation. Thus, estrogen and androgen regulate specific genes in seminiferous tubules that could play a role in spermiation.
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Affiliation(s)
- Anita Kumar
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Kushaan Dumasia
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Reshma Gaonkar
- Confocal Facility, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Shobha Sonawane
- Confocal Facility, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - Leena Kadam
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India
| | - N H Balasinor
- Deparment of Neuroendocrinology, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Parel, Mumbai 400012, India.
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Demais V, Audrain C, Mabilleau G, Chappard D, Baslé MF. Diversity of bone matrix adhesion proteins modulates osteoblast attachment and organization of actin cytoskeleton. Morphologie 2014; 98:53-64. [PMID: 24735942 DOI: 10.1016/j.morpho.2014.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 02/12/2014] [Indexed: 06/03/2023]
Abstract
Interaction of cells with extracellular matrix is an essential event for differentiation, proliferation and activity of osteoblasts. In bone, binding of osteoblasts to bone matrix is required to determine specific activities of the cells and to synthesize matrix bone proteins. Integrins are the major cell receptors involved in the cell linkage to matrix proteins such as fibronectin, type I collagen and vitronectin, via the RGD-sequences. In this study, cultures of osteoblast-like cells (Saos-2) were done on coated glass coverslips in various culture conditions: DMEM alone or DMEM supplemented with poly-L-lysine (PL), fetal calf serum (FCS), fibronectin (FN), vitronectin (VN) and type I collagen (Col-I). The aim of the study was to determine the specific effect of these bone matrix proteins on cell adherence and morphology and on the cytoskeleton status. Morphological characteristics of cultured cells were studied using scanning electron microscopy and image analysis. The heterogeneity of cytoskeleton was studied using fractal analysis (skyscrapers and blanket algorithms) after specific preparation of cells to expose the cytoskeleton. FAK and MAPK signaling pathways were studied by western blotting in these various culture conditions. Results demonstrated that cell adhesion was reduced with PL and VN after 240 min. After 60 min of adhesion, cytoskeleton organization was enhanced with FN, VN and Col-I. No difference in FAK phosphorylation was observed but MAPK phosphorylation was modulated by specific adhesion on extracellular proteins. These results indicate that culture conditions modulate cell adhesion, cytoskeleton organization and intracellular protein pathways according to extracellular proteins present for adhesion.
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Affiliation(s)
- V Demais
- Groupe études remodelage osseux et biomatériaux (GEROM), LHEA, IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France
| | - C Audrain
- Groupe études remodelage osseux et biomatériaux (GEROM), LHEA, IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France; Service commun d'imageries et d'analyses microscopiques (SCIAM), IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France
| | - G Mabilleau
- Groupe études remodelage osseux et biomatériaux (GEROM), LHEA, IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France; Service commun d'imageries et d'analyses microscopiques (SCIAM), IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France
| | - D Chappard
- Groupe études remodelage osseux et biomatériaux (GEROM), LHEA, IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France; Service commun d'imageries et d'analyses microscopiques (SCIAM), IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France.
| | - M F Baslé
- Groupe études remodelage osseux et biomatériaux (GEROM), LHEA, IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France; Service commun d'imageries et d'analyses microscopiques (SCIAM), IRIS-IBS (institut de biologie en santé), LUNAM université, CHU d'Angers, 49933 Angers cedex, France
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Specific inhibitory effects of the NO donor MAHMA/NONOate on human platelets. Eur J Pharmacol 2014; 735:169-76. [PMID: 24780647 DOI: 10.1016/j.ejphar.2014.04.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 04/16/2014] [Accepted: 04/17/2014] [Indexed: 01/30/2023]
Abstract
Nitric oxide (NO) is a physiological inhibitor of platelet function and has vaso-dilating effects. Therefore, synthesized NO releasing agents are used e.g. in cardiovascular medicine. The aim of this study was to characterise specific effects of the short living agent MAHMA/NONOate, a NO donor of the diazeniumdiolate class, on human platelets. Whole blood was obtained from healthy volunteers. In washed human platelets, the MAHMA/NONOate induced phosphorylation of the vasodilator-stimulated phosphoprotein (VASP) and cyclic nucleotide production were studied by Western Blot and by enzyme immunoassay kits. Agonist induced aggregation was measured in platelet rich plasma. Paired Student׳s t-test was used for statistical analysis. MAHMA/NONOate significantly stimulated platelet VASP phosphorylation in a concentration dependent manner and increased intracellular cGMP, but not cAMP levels, transiently. ODQ, a specific inhibitor of the soluble guanylyl cyclase, completely prevented VASP phosphorylation induced by low MAHMA/NONOate concentrations (5nM-15nM). The effects of higher concentrations (30-200nM) were only partially inhibited by ODQ. MAHMA/NONOate reduced platelet aggregation induced by low doses of agonists (2µM ADP, 0.5µg/mL collagen, 5µM TRAP-6) in a concentration dependent manner. MAHMA/NONOate leads to a rapid and transient activation of platelet inhibitory systems, accompanied by decreased platelet aggregation induced by low dose agonists. At low MAHMA/NONOate concentrations, the effects are cGMP dependent and at higher concentrations additionally cGMP independent. The substance could be of interest for clinical situations requiring transient and subtotal inhibition of platelet function.
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Multiscale modeling of cell shape from the actin cytoskeleton. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 123:143-67. [PMID: 24560144 DOI: 10.1016/b978-0-12-397897-4.00002-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The actin cytoskeleton is a dynamic structure that constantly undergoes complex reorganization events during many cellular processes. Mathematical models and simulations are powerful tools that can provide insight into the physical mechanisms underlying these processes and make predictions that can be experimentally tested. Representation of the interactions of the actin filaments with the plasma membrane and the movement of the plasma membrane for computation remains a challenge. Here, we provide an overview of the different modeling approaches used to study cytoskeletal dynamics and highlight the differential geometry approach that we have used to implement the interactions between the plasma membrane and the cytoskeleton. Using cell spreading as an example, we demonstrate how this approach is able to successfully capture in simulations, experimentally observed behavior. We provide a perspective on how the differential geometry approach can be used for other biological processes.
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30
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Döppler H, Storz P. Regulation of VASP by phosphorylation: consequences for cell migration. Cell Adh Migr 2013; 7:482-6. [PMID: 24401601 DOI: 10.4161/cam.27351] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Phosphorylations control all aspects of vasodilator-stimulated phospho-protein (VASP) function. Mapped phosphorylation sites include Y39, S157, S239, T278, and S322, and multiple kinases have been shown to mediate their phosphorylation. Recently, Protein Kinase D1 (PKD1) as a direct kinase for S157 and S322 joined this group. While S157 phosphorylation generally seems to serve as a signal for membrane localization, phosphorylations at S322 or at S239 and T278 have opposite effects on F-actin accumulation. In migrating cells, S322 phosphorylation increases filopodia numbers and length, while S239/T278 phosphorylations decrease these and also disrupt formation of focal adhesions. Therefore, the kinases mediating these phosphorylations can be seen as switches needed to facilitate cell motility.
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Affiliation(s)
- Heike Döppler
- Department of Cancer Biology; Mayo Clinic Comprehensive Cancer Center; Mayo Clinic; Jacksonville, FL USA
| | - Peter Storz
- Department of Cancer Biology; Mayo Clinic Comprehensive Cancer Center; Mayo Clinic; Jacksonville, FL USA
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31
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Spracklen AJ, Kelpsch DJ, Chen X, Spracklen CN, Tootle TL. Prostaglandins temporally regulate cytoplasmic actin bundle formation during Drosophila oogenesis. Mol Biol Cell 2013; 25:397-411. [PMID: 24284900 PMCID: PMC3907279 DOI: 10.1091/mbc.e13-07-0366] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Tight regulation of actin remodeling is essential for development, and misregulation results in disease. Cytoskeletal dynamics are regulated by prostaglandins (PGs)—lipid signals. PGs temporally regulate actin remodeling during Drosophila oogenesis, at least in part, by modulating the activity of the actin elongation factor Enabled. Prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin dynamics in cell culture and platelets, but their roles during development are largely unknown. Here we define a new role for Pxt, the Drosophila COX-like enzyme, in regulating the actin cytoskeleton—temporal restriction of actin remodeling during oogenesis. PGs are required for actin filament bundle formation during stage 10B (S10B). In addition, loss of Pxt results in extensive early actin remodeling, including actin filaments and aggregates, within the posterior nurse cells of S9 follicles; wild-type follicles exhibit similar structures at a low frequency. Hu li tai shao (Hts-RC) and Villin (Quail), an actin bundler, localize to all early actin structures, whereas Enabled (Ena), an actin elongation factor, preferentially localizes to those in pxt mutants. Reduced Ena levels strongly suppress early actin remodeling in pxt mutants. Furthermore, loss of Pxt results in reduced Ena localization to the sites of bundle formation during S10B. Together these data lead to a model in which PGs temporally regulate actin remodeling during Drosophila oogenesis by controlling Ena localization/activity, such that in S9, PG signaling inhibits, whereas at S10B, it promotes Ena-dependent actin remodeling.
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Affiliation(s)
- Andrew J Spracklen
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242 Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242
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32
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El-Sehemy A, Chang AC, Azad AK, Gupta N, Xu Z, Steed H, Karsan A, Fu Y. Notch activation augments nitric oxide/soluble guanylyl cyclase signaling in immortalized ovarian surface epithelial cells and ovarian cancer cells. Cell Signal 2013; 25:2780-7. [PMID: 24041655 DOI: 10.1016/j.cellsig.2013.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Accepted: 09/06/2013] [Indexed: 11/25/2022]
Abstract
Nitric oxide (NO) is generated by tumor, stromal and endothelial cells and plays a multifaceted role in tumor biology. Many physiological functions of NO are mediated by soluble guanylyl cyclase (sGC) and NO/sGC signaling has been shown to promote proliferation and survival of ovarian cancer cells. However, how NO/sGC signaling is modulated in ovarian cancer cells has not been studied. The evolutionarily conserved Notch signaling pathway plays an oncogenic role in ovarian cancer. Here, we report that all three ovarian cancer cell lines we examined express a higher level of GUCY1B3 (the β subunit of sGC) compared to non-cancerous immortalized ovarian surface epithelial (IOSE) cell lines. Interestingly, the highest expression of GUCY1B3 in ovarian cancer OVCAR3 cells is concurrent with the expression of Notch3. In IOSE cells, forced activation of Notch3 increases the expression of GUCY1B3, NO-induced cGMP production, and the expression of cGMP-dependent protein kinase (PKG), thereby enhancing NO- and cGMP-induced phosphorylation of vasodilator-stimulated phosphoprotein (VASP, a direct PKG substrate protein). In contrast, inhibition of Notch by DAPT reduces GUCY1B3 expression and NO-induced cGMP production and VASP phosphorylation in OVCAR3 cells. Finally, we confirmed that inhibition of sGC by ODQ decreases growth of ovarian cancer cells. Together, our work demonstrates that Notch is a positive regulator of NO/sGC signaling in IOSE and ovarian cancer cells, providing the first evidence that Notch and NO signaling pathways interact in IOSE and ovarian cancer cells.
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Affiliation(s)
- Ahmed El-Sehemy
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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33
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Döppler HR, Bastea LI, Lewis-Tuffin LJ, Anastasiadis PZ, Storz P. Protein kinase D1-mediated phosphorylations regulate vasodilator-stimulated phosphoprotein (VASP) localization and cell migration. J Biol Chem 2013; 288:24382-93. [PMID: 23846685 PMCID: PMC3750140 DOI: 10.1074/jbc.m113.474676] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/08/2013] [Indexed: 11/06/2022] Open
Abstract
Enabled/Vasodilator-stimulated phosphoprotein (Ena/VASP) protein family members link actin dynamics and cellular signaling pathways. VASP localizes to regions of dynamic actin reorganization such as the focal adhesion contacts, the leading edge or filopodia, where it contributes to F-actin filament elongation. Here we identify VASP as a novel substrate for protein kinase D1 (PKD1). We show that PKD1 directly phosphorylates VASP at two serine residues, Ser-157 and Ser-322. These phosphorylations occur in response to RhoA activation and mediate VASP re-localization from focal contacts to the leading edge region. The net result of this PKD1-mediated phosphorylation switch in VASP is increased filopodia formation and length at the leading edge. However, such signaling when persistent induced membrane ruffling and decreased cell motility.
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Affiliation(s)
- Heike R. Döppler
- From the Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Jacksonville, Florida 32224
| | - Ligia I. Bastea
- From the Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Jacksonville, Florida 32224
| | - Laura J. Lewis-Tuffin
- From the Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Jacksonville, Florida 32224
| | - Panos Z. Anastasiadis
- From the Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Jacksonville, Florida 32224
| | - Peter Storz
- From the Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Mayo Clinic, Jacksonville, Florida 32224
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34
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Borgognone A, Lowe KL, Watson SP, Madhani M. Natriuretic peptides induce weak VASP phosphorylation at Serine 239 in platelets. Platelets 2013; 25:1-7. [PMID: 23469931 DOI: 10.3109/09537104.2013.773969] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cyclic guanosine-3',5'-monophoshate (cGMP) is the common second messenger for the cardiovascular effects of nitric oxide (NO) and natriuretic peptides (NP; e.g. atrial NP [ANP]), which activate soluble and particulate guanylyl cyclases, respectively. The role of NO in regulating cGMP and platelet function is well documented, whereas there is little evidence supporting a role for NPs in regulating platelet reactivity. By studying platelet aggregation and secretion in response to a PAR-1 peptide, collagen and ADP, and phosphorylation of the cGMP-dependent protein kinase (PKG) substrate vasodilator-stimulated phosphoprotein (VASP) at serine 239, we evaluated the effects of NPs in the absence or presence of the non-selective cGMP and cAMP phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX). Our results show that NPs, possibly through the clearance receptor (natriuretic peptide receptor-C) expressed on platelet membranes, increase VASP phosphorylation but only following PDE inhibition, indicating a small, localised cGMP synthesis. As platelet aggregation and secretion measured under the same conditions were not affected, we conclude that the magnitude of PKG activation achieved by NPs in platelets per se is not sufficient to exert functional inhibition of platelet involvement in haemostasis.
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Affiliation(s)
- Alessandra Borgognone
- Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham , Birmingham , UK
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35
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Ikeda Y, Sudo T, Kimura Y. Cilostazol. Platelets 2013. [DOI: 10.1016/b978-0-12-387837-3.00057-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Multiple actin binding domains of Ena/VASP proteins determine actin network stiffening. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 41:979-90. [DOI: 10.1007/s00249-012-0861-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/18/2012] [Accepted: 09/06/2012] [Indexed: 02/04/2023]
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37
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Begonja AJ, Gambaryan S, Schulze H, Patel-Hett S, Italiano JE, Hartwig JH, Walter U. Differential roles of cAMP and cGMP in megakaryocyte maturation and platelet biogenesis. Exp Hematol 2012; 41:91-101.e4. [PMID: 22981933 DOI: 10.1016/j.exphem.2012.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/24/2012] [Accepted: 09/03/2012] [Indexed: 10/27/2022]
Abstract
The cyclic nucleotides cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) regulate the activity of protein kinase A (PKA) and protein kinase G (PKG), respectively. This process helps maintain circulating platelets in a resting state. Here we studied the role of cAMP and cGMP in the regulation of megakaryocyte (MK) differentiation and platelet formation. Cultured, platelet-producing MKs were differentiated from fetal livers harvested from 13.5 days postcoital mouse embryos. MK development was accompanied by a dramatic increase in cAMP production and expression of soluble guanylate cyclase, PKG, and PKA as well as their downstream targets vasodilator-stimulated phosphoprotein (VASP) and MENA. Stimulation of prostaglandin E(1) receptor/adenylyl cyclase or soluble guanylate cyclase/PKG in cultured MKs increased VASP phosphorylation, indicating that these components share a common signaling pathway. To dissect out the role of cyclic nucleotides in MK differentiation, cAMP/PKA and cGMP/PKG signaling were alternately blocked in cultured MKs. Down-regulation of cAMP pathway effectors decreased MK numbers and ploidy. Notably, cGMP levels increased at the beginning of MK development and returned to basal levels in parallel with MK maturation. However, inhibition of cGMP pathway effectors had no effect on MK development. In addition, platelet release from mature MKs was enhanced by cGMP and inhibited by cAMP. Our data suggest that cAMP plays an important role in MK differentiation, while cAMP and cGMP have opposite effects on platelet production. Identifying the signaling pathways that underpin MK development and proplatelet formation will provide greater insights into thrombopoiesis and may potentially yield useful therapeutic targets.
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Affiliation(s)
- Antonija Jurak Begonja
- Institute of Clinical Biochemistry and Pathobiochemistry, University of Würzburg, Würzburg, Germany.
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38
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Jennissen K, Siegel F, Liebig-Gonglach M, Hermann MR, Kipschull S, van Dooren S, Kunz WS, Fässler R, Pfeifer A. A VASP-Rac-soluble guanylyl cyclase pathway controls cGMP production in adipocytes. Sci Signal 2012; 5:ra62. [PMID: 22932701 DOI: 10.1126/scisignal.2002867] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The ubiquitous second messenger cyclic guanosine monophosphate (cGMP) plays an important role in metabolism and promotes brown adipocyte differentiation. We showed that ablation of the gene encoding vasodilator-stimulated phosphoprotein (VASP), a major downstream component of the cGMP signaling cascade, increased cellular cGMP content in brown and white adipocytes and mouse embryonic fibroblasts. VASP-deficient cells showed increased activation of Rac1, which in turn increased the abundance of the cGMP-producing enzyme soluble guanylyl cyclase (sGC), the main receptor for nitric oxide. Consequently, loss of VASP caused increased cGMP concentrations and enhanced brown adipocyte differentiation. Consistent with the in vitro data, we found increased energy expenditure in VASP-deficient mice and exposure to cold triggered enhanced lipolysis and cellular respiration in VASP-deficient brown fat cells. In addition, VASP-deficient mice exhibited increased development of brown-like adipocytes in white fat. Our data revealed that a VASP to Rac to sGC negative feedback loop limited cGMP production, thereby regulating adipogenesis and energy homeostasis.
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Affiliation(s)
- Katja Jennissen
- Institute of Pharmacology and Toxicology, University of Bonn, 53105 Bonn, Germany
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39
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Joshi CN, Martin DN, Shaver P, Madamanchi C, Muller-Borer BJ, Tulis DA. Control of vascular smooth muscle cell growth by connexin 43. Front Physiol 2012; 3:220. [PMID: 22737133 PMCID: PMC3380337 DOI: 10.3389/fphys.2012.00220] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 06/01/2012] [Indexed: 12/04/2022] Open
Abstract
Connexin 43 (Cx43), the principal gap junction protein in vascular smooth muscle cells (VSMCs), regulates movement of ions and other signaling molecules through gap junction intercellular communication (GJIC) and plays important roles in maintaining normal vessel function; however, many of the signaling mechanisms controlling Cx43 in VSMCs are not clearly described. The goal of this study was to investigate mechanisms of Cx43 regulation with respect to VSMC proliferation. Treatment of rat primary VSMCs with the cAMP analog 8Br-cAMP, the soluble guanylate cyclase (sGC) stimulator BAY 41-2272 (BAY), or the Cx inducer diallyl disulfide (DADS) significantly reduced proliferation after 72 h compared with vehicle controls. Bromodeoxyuridine uptake revealed reduction (p < 0.05) in DNA synthesis after 6 h and flow cytometry showed reduced (40%) S-phase cell numbers after 16 h in DADS-treated cells compared with vehicle controls. Cx43 expression significantly increased after 270 min treatment with 8Br-cAMP, 8Br-cGMP, BAY or DADS. Inhibition of PKA, PKG or PKC reversed 8Br-cAMP-stimulated increases in Cx43 expression, whereas only PKG or PKC inhibition reversed 8Br-cGMP- and BAY-stimulated increases in total Cx43. Interestingly, stimulation of Cx43 expression by DADS was not dependent on PKA, PKG or PKC. Using fluorescence recovery after photobleaching, only 8Br-cAMP or DADS increased GJIC with 8Br-cAMP mediated by PKC and DADS mediated by PKG. Further, DADS significantly increased phosphorylation at MAPK-sensitive Serine (Ser)255 and Ser279, the cell cycle regulatory kinase-sensitive Ser262 and PKC-sensitive Ser368 after 30 min while 8Br-cAMP significantly increased phosphorylation only at Ser279 compared with controls. This study demonstrates that 8Br-cAMP- and DADS-enhanced GJIC rather than Cx43 expression and/or phosphorylation plays important roles in the regulation of VSMC proliferation and provides new insights into the growth-regulatory capacities of Cx43 in VSM.
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Affiliation(s)
- Chintamani N Joshi
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
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40
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Campbell AL, Shih HP, Xu J, Gross MK, Kioussi C. Regulation of motility of myogenic cells in filling limb muscle anlagen by Pitx2. PLoS One 2012; 7:e35822. [PMID: 22558231 PMCID: PMC3338778 DOI: 10.1371/journal.pone.0035822] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 03/22/2012] [Indexed: 01/09/2023] Open
Abstract
Cells of the ventrolateral dermomyotome delaminate and migrate into the limb buds where they give rise to all muscles of the limbs. The migratory cells proliferate and form myoblasts, which withdraw from the cell cycle to become terminally differentiated myocytes. The myogenic lineage colonizes pre-patterned regions to form muscle anlagen as muscle fibers are assembled. The regulatory mechanisms that control the later steps of this myogenic program are not well understood. The homeodomain transcription factor Pitx2 is expressed specifically in the muscle lineage from the migration of precursors to adult muscle. Ablation of Pitx2 results in distortion, rather than loss, of limb muscle anlagen, suggesting that its function becomes critical during the colonization of, and/or fiber assembly in, the anlagen. Microarrays were used to identify changes in gene expression in flow-sorted migratory muscle precursors, labeled by Lbx1(EGFP/+), which resulted from the loss of Pitx2. Very few genes showed changes in expression. Many small-fold, yet significant, changes were observed in genes encoding cytoskeletal and adhesion proteins which play a role in cell motility. Myogenic cells from genetically-tagged mice were cultured and subjected to live cell-tracking analysis using time-lapse imaging. Myogenic cells lacking Pitx2 were smaller, more symmetrical, and had more actin bundling. They also migrated about half of the total distance and velocity. Decreased motility may prevent myogenic cells from filling pre-patterned regions of the limb bud in a timely manner. Altered shape may prevent proper assembly of higher-order fibers within anlagen. Pitx2 therefore appears to regulate muscle anlagen development by appropriately balancing expression of cytoskeletal and adhesion molecules.
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Affiliation(s)
- Adam L. Campbell
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon, United States of America
| | - Hung-Ping Shih
- Department of Pediatrics, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Jun Xu
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon, United States of America
| | - Michael K. Gross
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon, United States of America
| | - Chrissa Kioussi
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon, United States of America
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41
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Broos K, De Meyer SF, Feys HB, Vanhoorelbeke K, Deckmyn H. Blood platelet biochemistry. Thromb Res 2011; 129:245-9. [PMID: 22119499 DOI: 10.1016/j.thromres.2011.11.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 10/27/2011] [Accepted: 11/02/2011] [Indexed: 12/12/2022]
Abstract
Defects in platelet function or formation increase the risk for bleeding or thrombosis, which indicates the crucial role for platelets in maintaining haemostasis in normal life. Upon vascular injury, platelets instantly adhere to the exposed extracellular matrix which results in platelet activation and aggregation and the formation a haemostatic plug that stops bleeding. To prevent excessive platelet aggregate formation that eventually would occlude the vessels, this self-amplifying process nevertheless requires a tight control. This review intends to give a comprehensive overview of the currently established main mechanisms in platelet function.
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Affiliation(s)
- Katleen Broos
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven campus Kortrijk, Kortrijk, Belgium
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42
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Joshi CN, Martin DN, Fox JC, Mendelev NN, Brown TA, Tulis DA. The soluble guanylate cyclase stimulator BAY 41-2272 inhibits vascular smooth muscle growth through the cAMP-dependent protein kinase and cGMP-dependent protein kinase pathways. J Pharmacol Exp Ther 2011; 339:394-402. [PMID: 21825001 DOI: 10.1124/jpet.111.183400] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Vascular smooth muscle (VSM) proliferation and migration are key components in vessel remodeling. Cyclic nucleotide signaling is protective and has long-served as a therapeutic target against undesired VSM growth. The present work analyzed the effects of the soluble guanylate cyclase (sGC) stimulator 3-(4-amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine [BAY 41-2272 (BAY)] on VSM growth, and we hypothesize that BAY has the capacity to reduce proliferation and migration via cyclic nucleotide-driven kinase signaling. Perivascular BAY postballoon injury reduced neointimal growth by ∼ 40% compared with vehicle controls after 2 weeks. In VSM cells, BAY (10 μM) reduced proliferation by ∼ 40% after 72 h and migration by ∼ 40% after 6 h and ∼ 60% after 18 h without deleterious effects on cell viability. cGMP content peaked (248 ×) 20 min after BAY treatment and remained elevated (140 ×) through 60 min; however, BAY did not affect cAMP levels compared with controls. Conventional and In-Cell Western analyses showed increases in vasodilator-stimulated phosphoprotein (VASP) phosphorylation (pVASP) at serines 239 (3 ×) and 157 (2 ×), respective markers of cGMP- and cAMP-directed protein kinases (PKG and PKA, respectively). The PKG inhibitor YGRKKRRQRRRPPLRKKKKKH peptide (DT-2) completely reversed BAY-mediated increases in pVASPSer(239) and BAY-mediated inhibition of migration. In comparison, the PKA inhibitor peptide PKI further potentiated BAY-stimulated pVASPSer(157) and pVASPSer(239) and partially reversed the antiproliferative effects of BAY. This is the first report demonstrating the effectiveness of BAY in reducing neointimal growth with direct evidence for PKG-specific antimigratory and PKA-specific antiproliferative mechanisms. Conclusively, the sGC stimulator BAY reduces VSM growth through cGMP-dependent PKG and PKA processes, providing support for continued evaluation of its clinical utility.
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Affiliation(s)
- Chintamani N Joshi
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
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Zemskov E, Lucas R, Verin AD, Umapathy NS. P2Y receptors as regulators of lung endothelial barrier integrity. J Cardiovasc Dis Res 2011; 2:14-22. [PMID: 21716747 PMCID: PMC3120267 DOI: 10.4103/0975-3583.78582] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Endothelial cells (ECs), forming a semi-permeable barrier between the interior space of blood vessels and underlying tissues, control such diverse processes as vascular tone, homeostasis, adhesion of platelets, and leukocytes to the vascular wall and permeability of vascular wall for cells and fluids. Mechanisms which govern the highly clinically relevant process of increased EC permeability are under intense investigation. It is well known that loss of this barrier (permeability increase) results in tissue inflammation, the hall mark of inflammatory diseases such as acute lung injury and its severe form, acute respiratory distress syndrome. Little is known about processes which determine the endothelial barrier enhancement or protection against permeability increase. It is now well accepted that extracellular purines and pyrimidines are promising and physiologically relevant barrier-protective agents and their effects are mediated by interaction with cell surface P2Y receptors which belong to the superfamily of G-protein-coupled receptors. The therapeutic potential of P2Y receptors is rapidly expanding field in pharmacology and some selective agonists became recently available. Here, we present an overview of recently identified P2Y receptor agonists that enhance the pulmonary endothelial barrier and inhibit and/or reverse endothelial barrier disruption.
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Affiliation(s)
- Evgeny Zemskov
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912, USA
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Broos K, Feys HB, De Meyer SF, Vanhoorelbeke K, Deckmyn H. Platelets at work in primary hemostasis. Blood Rev 2011; 25:155-67. [PMID: 21496978 DOI: 10.1016/j.blre.2011.03.002] [Citation(s) in RCA: 272] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
When platelet numbers are low or when their function is disabled, the risk of bleeding is high, which on the one hand indicates that in normal life vascular damage is a rather common event and that hence the role of platelets in maintaining a normal hemostasis is a continuously ongoing physiological process. Upon vascular injury, platelets instantly adhere to the exposed extracellular matrix resulting in platelet activation and aggregation to form a hemostatic plug. This self-amplifying mechanism nevertheless requires a tight control to prevent uncontrolled platelet aggregate formation that eventually would occlude the vessel. Therefore endothelial cells produce inhibitory compounds such as prostacyclin and nitric oxide that limit the growth of the platelet thrombus to the damaged area. With this review, we intend to give an integrated survey of the platelet response to vascular injury in normal hemostasis.
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Affiliation(s)
- Katleen Broos
- Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kortrijk, Belgium.
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Spatial and temporal expression of vasodilator‐stimulated phosphoprotein (VASP) in fetal and adult human cerebral cortex. Int J Dev Neurosci 2010; 29:131-6. [DOI: 10.1016/j.ijdevneu.2010.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 12/03/2010] [Accepted: 12/07/2010] [Indexed: 11/22/2022] Open
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Tuduce IL, Schuh K, Bundschu K. Spred2 expression during mouse development. Dev Dyn 2010; 239:3072-85. [DOI: 10.1002/dvdy.22432] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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The noncanonical Gag domains p8 and n are critical for assembly and release of mouse mammary tumor virus. J Virol 2010; 84:11555-9. [PMID: 20739518 DOI: 10.1128/jvi.00652-10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The mouse mammary tumor virus (MMTV) Gag contains the unique domains pp21, p3, p8, and n. We investigated the contribution of these domains to particle assembly and found that the region spanning the p8 and n domains is critical for shape determination and assembly. Deletion of pp21 and p3 reduced the number of released particles, but deletion of the n domain resulted in frequent formation of aberrant particles, while deletion of p8 severely impaired assembly. Further investigation of p8 revealed that both the basic and the proline-rich motifs within p8 contribute to MMTV assembly.
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Geiger J, Brandmann T, Hubertus K, Tjahjadi B, Schinzel R, Walter U. A protein phosphorylation-based assay for screening and monitoring of drugs modulating cyclic nucleotide pathways. Anal Biochem 2010; 407:261-9. [PMID: 20708596 DOI: 10.1016/j.ab.2010.08.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 08/04/2010] [Accepted: 08/04/2010] [Indexed: 10/19/2022]
Abstract
Cyclic nucleotide regulation is an important target for drug development, particularly for treatment and prophylaxis of cardiovascular diseases. Determination of cyclic nucleotide levels for screening and monitoring of cyclic nucleotide modulating drug action is necessary, yet the techniques available are cumbersome and not sufficiently accurate. Here we present an approach based on the detection of cyclic nucleotide-dependent protein phosphorylation. By use of a common substrate of cyclic nucleotide-dependent protein kinases, the protein vasodilator-stimulated phosphoprotein (VASP) featuring two phosphorylation sites specifically phosphorylated by these kinases, an assay was developed for the monitoring of intracellular cyclic nucleotide levels. The assay was tested with human platelets ex vivo treated with stimulants of nucleotide cyclases, kinases, and phosphodiesterase inhibitors. Phosphorylation of the protein VASP correlates with intracellular cyclic nucleotide concentration (R(2)>0.90 for cGMP and cAMP); however, VASP phosphorylation is more sensitive to elevated cyclic nucleotide levels and significantly more stable over time. Quantification of VASP phosphorylation offers a reliable and robust tool for fast and easy monitoring of cyclic nucleotide levels and is also applicable to unprocessed biological matrices. Owing to these properties, VASP is a promising biomarker for screening and monitoring of cyclic nucleotide modulating drugs.
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Affiliation(s)
- Jörg Geiger
- Institute for Clinical Biochemistry and Pathobiochemistry, University of Würzburg, 97080 Würzburg, Germany.
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Wang Y, Dong H, Zhu M, Ou Y, Zhang J, Luo H, Luo R, Wu J, Mao M, Liu X, Zhang J, Wei L. Icariin exterts negative effects on human gastric cancer cell invasion and migration by vasodilator-stimulated phosphoprotein via Rac1 pathway. Eur J Pharmacol 2010; 635:40-8. [DOI: 10.1016/j.ejphar.2010.03.017] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 02/18/2010] [Accepted: 03/04/2010] [Indexed: 11/29/2022]
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Deevi RK, Koney-Dash M, Kissenpfennig A, Johnston JA, Schuh K, Walter U, Dib K. Vasodilator-stimulated phosphoprotein regulates inside-out signaling of beta2 integrins in neutrophils. THE JOURNAL OF IMMUNOLOGY 2010; 184:6575-84. [PMID: 20483741 DOI: 10.4049/jimmunol.0903910] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The monomeric GTPase Rap1 controls functional activation of beta2 integrins in leukocytes. In this article, we describe a novel mechanism by which the chemoattractant fMLP activates Rap1 and inside-out signaling of beta2 integrins. We found that fMLP-induced activation of Rap1 in human polymorphonuclear leukocytes or neutrophils and differentiated PLB-985 cells was blocked by inhibitors of the NO/guanosine-3',5'-cyclic monophosphate-dependent protein kinase (cGKI) pathway [N-(3-(aminomethyl)benzyl)acetamidine, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, DT-3 peptide, 8-(4-chlorophenylthio)guanosine 3',5'-cyclic monophosphothioate, Rp-isomer triethylammonium salt-guanosine-3',5'-cyclic monophosphate], indicating that the downstream signaling events in Rap1 activation involve the production of NO and guanosine-3',5'-cyclic monophosphate, as well as the activation of cGKI. Silencing the expression of vasodilator-stimulated phosphoprotein (VASP), a substrate of cGKI, in resting PLB-985 cells or mice neutrophils led to constitutive activation of Rap1. In parallel, silencing VASP in differentiated PLB-985 cells led to recruitment of C3G, a guanine nucleotide exchange factor for Rap1, to the plasma membrane. Expression of murine GFP-tagged phosphodeficient VASP Ser235Ala mutant (murine serine 235 of VASP corresponds to human serine 239) in PLB-985 cells blunted fMLP-induced translocation of C3G to the membrane and activation of Rap1. Thus, bacterial fMLP triggers cGKI-dependent phosphorylation of human VASP on serine 239 and, thereby, controls membrane recruitment of C3G, which is required for activation of Rap1 and beta2 integrin-dependent antibacterial functions of neutrophils.
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Affiliation(s)
- Ravi K Deevi
- Centre for Infection and Immunity, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
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