1
|
Liang Y, Kang X, Zhang H, Xu H, Wu X. Knockdown and inhibition of hippocampal GPR17 attenuates lipopolysaccharide-induced cognitive impairment in mice. J Neuroinflammation 2023; 20:271. [PMID: 37990234 PMCID: PMC10662506 DOI: 10.1186/s12974-023-02958-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 11/13/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND Previously we reported that inhibition of GPR17 prevents amyloid β 1-42 (Aβ1-42)-induced cognitive impairment in mice. However, the role of GPR17 on cognition is still largely unknown. METHODS Herein, we used a mouse model of cognitive impairment induced by lipopolysaccharide (LPS) to further investigate the role of GPR17 in cognition and its potential mechanism. The mice were pretreated with GPR17 shRNA lentivirus and cangrelor by microinjection into the dentate gyrus (DG) region of the hippocampus. After 21 days, LPS (0.25 mg/kg, i.p.) was administered for 7 days. Animal behavioral tests as well as pathological and biochemical assays were performed to evaluate the cognitive function in mice. RESULTS LPS exposure resulted in a significant increase in GPR17 expression at both protein and mRNA levels in the hippocampus. Gene reduction and pharmacological blockade of GPR17 improved cognitive impairment in both the Morris water maze and novel object recognition tests. Knockdown and inhibition of GPR17 inhibited Aβ production, decreased the expression of NF-κB p65, increased CREB phosphorylation and elevated BDNF expression, suppressed the accumulation of pro-inflammatory cytokines, inhibited Glial cells (microglia and astrocytes) activation, and increased Bcl-2, PSD-95, and SYN expression, reduced Bax expression as well as decreased caspase-3 activity and TUNEL-positive cells in the hippocampus of LPS-treated mice. Notably, knockdown and inhibition of GPR17 not only provided protective effects against cholinergic dysfunction but also facilitated the regulation of oxidative stress. In addition, cangrelor pretreatment can effectively inhibit the expression of inflammatory cytokines by suppressing NF-κB/CREB/BDNF signaling in BV-2 cells stimulated by LPS. However, activation of hippocampal GPR17 with MDL-29951 induced cognitive impairment in normal mice. CONCLUSIONS These observations indicate that GPR17 may possess a neuroprotective effect against LPS-induced cognition deficits, and neuroinflammation by modulation of NF-κB/CREB/BDNF signaling in mice, indicating that GPR17 may be a promising new target for the prevention and treatment of AD.
Collapse
Affiliation(s)
- Yusheng Liang
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, 230032, China
- Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Hefei, 230032, China
| | - Xu Kang
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, 230032, China
- Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Hefei, 230032, China
| | - Haiwang Zhang
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, 230032, China
- Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Hefei, 230032, China
| | - Heng Xu
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, 230032, China
- Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Hefei, 230032, China
| | - Xian Wu
- Anhui Province Key Laboratory of Major Autoimmune Diseases, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, 230032, China.
- Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Hefei, 230032, China.
| |
Collapse
|
2
|
Changes in Hippocampal Plasticity in Depression and Therapeutic Approaches Influencing These Changes. Neural Plast 2020; 2020:8861903. [PMID: 33293948 PMCID: PMC7718046 DOI: 10.1155/2020/8861903] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/30/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Depression is a common neurological disease that seriously affects human health. There are many hypotheses about the pathogenesis of depression, and the most widely recognized and applied is the monoamine hypothesis. However, no hypothesis can fully explain the pathogenesis of depression. At present, the brain-derived neurotrophic factor (BDNF) and neurogenesis hypotheses have highlighted the important role of plasticity in depression. The plasticity of neurons and glial cells plays a vital role in the transmission and integration of signals in the central nervous system. Plasticity is the adaptive change in the nervous system in response to changes in external signals. The hippocampus is an important anatomical area associated with depression. Studies have shown that some antidepressants can treat depression by changing the plasticity of the hippocampus. Furthermore, caloric restriction has also been shown to affect antidepressant and hippocampal plasticity changes. In this review, we summarize the latest research, focusing on changes in the plasticity of hippocampal neurons and glial cells in depression and the role of BDNF in the changes in hippocampal plasticity in depression, as well as caloric restriction and mitochondrial plasticity. This review may contribute to the development of antidepressant drugs and elucidating the mechanism of depression.
Collapse
|
3
|
Vandenbark AA, Meza-Romero R, Benedek G, Offner H. A novel neurotherapeutic for multiple sclerosis, ischemic injury, methamphetamine addiction, and traumatic brain injury. J Neuroinflammation 2019; 16:14. [PMID: 30683115 PMCID: PMC6346590 DOI: 10.1186/s12974-018-1393-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 12/27/2018] [Indexed: 02/08/2023] Open
Abstract
Neurovascular, autoimmune, and traumatic injuries of the central nervous system (CNS) all have in common an initial acute inflammatory response mediated by influx across the blood-brain barrier of activated mononuclear cells followed by chronic and often progressive disability. Although some anti-inflammatory therapies can reduce cellular infiltration into the initial lesions, there are essentially no effective treatments for the progressive phase. We here review the successful treatment of animal models for four separate neuroinflammatory and neurodegenerative CNS conditions using a single partial MHC class II construct called DRa1-hMOG-35-55 or its newest iteration, DRa1(L50Q)-hMOG-35-55 (DRhQ) that can be administered without a need for class II tissue type matching due to the conserved DRα1 moiety of the drug. These constructs antagonize the cognate TCR and bind with high affinity to their cell-bound CD74 receptor on macrophages and dendritic cells, thereby competitively inhibiting downstream signaling and pro-inflammatory effects of macrophage migration inhibitory factor (MIF) and its homolog, d-dopachrome tautomerase (D-DT=MIF-2) that bind to identical residues of CD74 leading to progressive disease. These effects suggest the existence of a common pathogenic mechanism involving a chemokine-driven influx of activated monocytes into the CNS tissue that can be reversed by parenteral injection of the DRa1-MOG-35-55 constructs that also induce anti-inflammatory macrophages and microglia within the CNS. Due to their ability to block this common pathway, these novel drugs appear to be prime candidates for therapy of a wide range of neuroinflammatory and neurodegenerative CNS conditions.
Collapse
Affiliation(s)
- Arthur A Vandenbark
- Neuroimmunology Research, R&D-31, VA Portland Health Care System, 3710 SW U.S. Veterans Hospital Rd., Portland, OR, 97239, USA. .,Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA. .,Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA.
| | - Roberto Meza-Romero
- Neuroimmunology Research, R&D-31, VA Portland Health Care System, 3710 SW U.S. Veterans Hospital Rd., Portland, OR, 97239, USA.,Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
| | - Gil Benedek
- Present Address: Tissue Typing and Immunogenetics Laboratory, Hadassah Medical Center, Jerusalem, Israel
| | - Halina Offner
- Neuroimmunology Research, R&D-31, VA Portland Health Care System, 3710 SW U.S. Veterans Hospital Rd., Portland, OR, 97239, USA.,Department of Neurology, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA.,Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
| |
Collapse
|
4
|
Sustained Activation of JNK Induced by Quinolinic Acid Alters the BDNF/TrkB Axis in the Rat Striatum. Neuroscience 2018; 383:22-32. [DOI: 10.1016/j.neuroscience.2018.04.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 04/10/2018] [Accepted: 04/24/2018] [Indexed: 12/26/2022]
|
5
|
Xu M, Han X, Liu R, Li Y, Qi C, Yang Z, Zhao C, Gao J. PDK1 Deficit Impairs the Development of the Dentate Gyrus in Mice. Cereb Cortex 2018; 29:1185-1198. [DOI: 10.1093/cercor/bhy024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Indexed: 12/22/2022] Open
Affiliation(s)
- Min Xu
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
| | - Xiaoning Han
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Histology and Embryology, School of Medicine, Southeast University, Nanjing, China
| | - Rui Liu
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
| | - Yanjun Li
- Model Animal Research Center of Nanjing University and MOE Key Laboratory of Model Animals for Disease Study, Nanjing, China
| | - Cui Qi
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
| | - Zhongzhou Yang
- Model Animal Research Center of Nanjing University and MOE Key Laboratory of Model Animals for Disease Study, Nanjing, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, MOE, Department of Histology and Embryology, School of Medicine, Southeast University, Nanjing, China
- Center of Depression, Beijing Institute for Brain Disorders, Beijing, China
| | - Jun Gao
- Department of Neurobiology, Nanjing Medical University, Nanjing, China
- Key Laboratory of Human Functional Genomics of Jiangsu, Nanjing Medical University, Nanjing, China
| |
Collapse
|
6
|
Xu C, Yu L, Hou J, Jackson RJ, Wang H, Huang C, Liu T, Wang Q, Zou X, Morris RG, Spires-Jones TL, Yang Z, Yin Z, Xu Y, Chen G. Conditional Deletion of PDK1 in the Forebrain Causes Neuron Loss and Increased Apoptosis during Cortical Development. Front Cell Neurosci 2017; 11:330. [PMID: 29104535 PMCID: PMC5655024 DOI: 10.3389/fncel.2017.00330] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/05/2017] [Indexed: 12/26/2022] Open
Abstract
Decreased expression but increased activity of PDK1 has been observed in neurodegenerative disease. To study in vivo function of PDK1 in neuron survival during cortical development, we generate forebrain-specific PDK1 conditional knockout (cKO) mice. We demonstrate that PDK1 cKO mice display striking neuron loss and increased apoptosis. We report that PDK1 cKO mice exhibit deficits on several behavioral tasks. Moreover, PDK1 cKO mice show decreased activities for Akt and mTOR. These results highlight an essential role of endogenous PDK1 in the maintenance of neuronal survival during cortical development.
Collapse
Affiliation(s)
- Congyu Xu
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Linjie Yu
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Jinxing Hou
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Rosemary J Jackson
- Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh, United Kingdom
| | - He Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Chaoli Huang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Tingting Liu
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Qihui Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Xiaochuan Zou
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Richard G Morris
- Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh, United Kingdom.,Consejo Superior de Investigaciones Científicas, Universidad Miguel Hernández, Instituto de Neurociencias, Alicante, Spain
| | - Tara L Spires-Jones
- Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Dementia Prevention, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Zhongzhou Yang
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| | - Zhenyu Yin
- Department of Geriatrics, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Guiquan Chen
- State Key Laboratory of Pharmaceutical Biotechnology, Model Animal Research Center, Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China
| |
Collapse
|
7
|
Mazel T. Crosstalk of cell polarity signaling pathways. PROTOPLASMA 2017; 254:1241-1258. [PMID: 28293820 DOI: 10.1007/s00709-017-1075-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/02/2017] [Indexed: 06/06/2023]
Abstract
Cell polarity, the asymmetric organization of cellular components along one or multiple axes, is present in most cells. From budding yeast cell polarization induced by pheromone signaling, oocyte polarization at fertilization to polarized epithelia and neuronal cells in multicellular organisms, similar mechanisms are used to determine cell polarity. Crucial role in this process is played by signaling lipid molecules, small Rho family GTPases and Par proteins. All these signaling circuits finally govern the cytoskeleton, which is responsible for oriented cell migration, cell shape changes, and polarized membrane and organelle trafficking. Thus, typically in the process of cell polarization, most cellular constituents become polarized, including plasma membrane lipid composition, ion concentrations, membrane receptors, and proteins in general, mRNA, vesicle trafficking, or intracellular organelles. This review gives a brief overview how these systems talk to each other both during initial symmetry breaking and within the signaling feedback loop mechanisms used to preserve the polarized state.
Collapse
Affiliation(s)
- Tomáš Mazel
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Albertov 4, 128 00, Prague 2, Czech Republic.
- State Institute for Drug Control, Šrobárova 48, 100 41, Prague 10, Czech Republic.
| |
Collapse
|
8
|
Mutation of the 3-Phosphoinositide-Dependent Protein Kinase 1 (PDK1) Substrate-Docking Site in the Developing Brain Causes Microcephaly with Abnormal Brain Morphogenesis Independently of Akt, Leading to Impaired Cognition and Disruptive Behaviors. Mol Cell Biol 2016; 36:2967-2982. [PMID: 27644329 DOI: 10.1128/mcb.00230-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/13/2016] [Accepted: 09/15/2016] [Indexed: 11/20/2022] Open
Abstract
The phosphoinositide (PI) 3-kinase/Akt signaling pathway plays essential roles during neuronal development. 3-Phosphoinositide-dependent protein kinase 1 (PDK1) coordinates the PI 3-kinase signals by activating 23 kinases of the AGC family, including Akt. Phosphorylation of a conserved docking site in the substrate is a requisite for PDK1 to recognize, phosphorylate, and activate most of these kinases, with the exception of Akt. We exploited this differential mechanism of regulation by generating neuron-specific conditional knock-in mice expressing a mutant form of PDK1, L155E, in which the substrate-docking site binding motif, termed the PIF pocket, was disrupted. As a consequence, activation of all the PDK1 substrates tested except Akt was abolished. The mice exhibited microcephaly, altered cortical layering, and reduced circuitry, leading to cognitive deficits and exacerbated disruptive behavior combined with diminished motivation. The abnormal patterning of the adult brain arises from the reduced ability of the embryonic neurons to polarize and extend their axons, highlighting the essential roles that the PDK1 signaling beyond Akt plays in mediating the neuronal responses that regulate brain development.
Collapse
|
9
|
Anglada-Huguet M, Giralt A, Rué L, Alberch J, Xifró X. Loss of striatal 90-kDa ribosomal S6 kinase (Rsk) is a key factor for motor, synaptic and transcription dysfunction in Huntington's disease. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1255-66. [DOI: 10.1016/j.bbadis.2016.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/09/2016] [Accepted: 04/03/2016] [Indexed: 12/20/2022]
|
10
|
Balakrishnan B, Chen W, Tang M, Huang X, Cakici DD, Siddiqi A, Berry G, Lai K. Galactose-1 phosphate uridylyltransferase (GalT) gene: A novel positive regulator of the PI3K/Akt signaling pathway in mouse fibroblasts. Biochem Biophys Res Commun 2016; 470:205-212. [PMID: 26773505 DOI: 10.1016/j.bbrc.2016.01.036] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 01/06/2016] [Indexed: 12/19/2022]
Abstract
The vital importance of the Leloir pathway of galactose metabolism has been repeatedly demonstrated by various uni-/multicellular model organisms, as well human patients who have inherited deficiencies of the key GAL enzymes. Yet, other than the obvious links to the glycolytic pathway and glycan biosynthetic pathways, little is known about how this metabolic pathway interacts with the rest of the metabolic and signaling networks. In this study, we compared the growth and the expression levels of the key components of the PI3K/Akt growth signaling pathway in primary fibroblasts derived from normal and galactose-1 phosphate uridylyltransferase (GalT)-deficient mice, the latter exhibited a subfertility phenotype in adult females and growth restriction in both sexes. The growth potential and the protein levels of the pAkt(Thr308), pAkt(Ser473), pan-Akt, pPdk1, and Hsp90 proteins were significantly reduced by 62.5%, 60.3%, 66%, 66%, and 50%, respectively in the GalT-deficient cells. Reduced expression of phosphorylated Akt proteins in the mutant cells led to diminished phosphorylation of Gsk-3β (-74%). Protein expression of BiP and pPten were 276% and 176% higher respectively in cells with GalT-deficiency. Of the 24 genes interrogated using QIAGEN RT(2) Profiler PCR Custom Arrays, the mRNA abundance of Akt1, Pdpk1, Hsp90aa1 and Pi3kca genes were significantly reduced at least 2.03-, 1.37-, 2.45-, and 1.78-fold respectively in mutant fibroblasts. Both serum-fasted normal and GalT-deficient cells responded to Igf-1-induced activation of Akt phosphorylation at +15 min, but the mutant cells have lower phosphorylation levels. The steady-state protein abundance of Igf-1 receptor was also significantly reduced in mutant cells. Our results thus demonstrated that GalT deficiency can effect down-regulation of the PI3K/Akt growth signaling pathway in mouse fibroblasts through distinct mechanisms targeting both gene and protein expression levels.
Collapse
Affiliation(s)
- Bijina Balakrishnan
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, USA
| | - Wyman Chen
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, USA
| | - Manshu Tang
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, USA
| | - Xiaoping Huang
- Division of Genetics and Genomics, Department of Pediatrics, Harvard Medical School, USA
| | - Didem Demirbas Cakici
- Division of Genetics and Genomics, Department of Pediatrics, Harvard Medical School, USA
| | - Anwer Siddiqi
- Department of Pathology and Laboratory Medicine, University of Florida College of Medicine, USA
| | - Gerard Berry
- Division of Genetics and Genomics, Department of Pediatrics, Harvard Medical School, USA
| | - Kent Lai
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, USA.
| |
Collapse
|
11
|
Kharebava G, Rashid MA, Lee JW, Sarkar S, Kevala K, Kim HY. N-docosahexaenoylethanolamine regulates Hedgehog signaling and promotes growth of cortical axons. Biol Open 2015; 4:1660-70. [PMID: 26545965 PMCID: PMC4736029 DOI: 10.1242/bio.013425] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Axonogenesis, a process for the establishment of neuron connectivity, is central to brain function. The role of metabolites derived from docosahexaenoic acid (DHA, 22:6n-3) that is specifically enriched in the brain, has not been addressed in axon development. In this study, we tested if synaptamide (N-docosahexaenoylethanolamine), an endogenous metabolite of DHA, affects axon growth in cultured cortical neurons. We found that synaptamide increased the average axon length, inhibited GLI family zinc finger 1 (GLI1) transcription and sonic hedgehog (Shh) target gene expression while inducing cAMP elevation. Similar effects were produced by cyclopamine, a regulator of the Shh pathway. Conversely, Shh antagonized elevation of cAMP and blocked synaptamide-mediated increase in axon length. Activation of Shh pathway by a smoothened (SMO) agonist (SAG) or overexpression of SMO did not inhibit axon growth mediated by synaptamide or cyclopamine. Instead, adenylate cyclase inhibitor SQ22536 abolished synaptamide-mediated axon growth indicating requirement of cAMP elevation for this process. Our findings establish that synaptamide promotes axon growth while Shh antagonizes synaptamide-mediated cAMP elevation and axon growth by a SMO-independent, non-canonical pathway. Summary: Synaptamide, an omega-3 fatty acid metabolite, promotes axon growth while Shh antagonizes synaptamide-mediated axon growth by a SMO-independent, non-canonical pathway.
Collapse
Affiliation(s)
- Giorgi Kharebava
- Laboratory of Molecular Signaling, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20852, USA
| | - Mohammad A Rashid
- Laboratory of Molecular Signaling, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20852, USA
| | - Ji-Won Lee
- Laboratory of Molecular Signaling, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20852, USA
| | - Sarmila Sarkar
- Laboratory of Molecular Signaling, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20852, USA
| | - Karl Kevala
- Laboratory of Molecular Signaling, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20852, USA
| | - Hee-Yong Kim
- Laboratory of Molecular Signaling, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20852, USA
| |
Collapse
|
12
|
HLA-DRα1-mMOG-35-55 treatment of experimental autoimmune encephalomyelitis reduces CNS inflammation, enhances M2 macrophage frequency, and promotes neuroprotection. J Neuroinflammation 2015; 12:123. [PMID: 26104759 PMCID: PMC4481122 DOI: 10.1186/s12974-015-0342-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 06/11/2015] [Indexed: 12/03/2022] Open
Abstract
Background DRα1-mouse(m)MOG-35-55, a novel construct developed in our laboratory as a simpler and potentially less immunogenic alternative to two-domain class II constructs, was shown previously to target the MIF/CD74 pathway and to reverse clinical and histological signs of experimental autoimmune encephalomyelitis (EAE) in DR*1501-Tg mice in a manner similar to the parent DR2β1-containing construct. Methods In order to determine whether DRα1-mMOG-35-55 could treat EAE in major histocompatibility complex (MHC)-mismatched mice and to evaluate the treatment effect on central nervous system (CNS) inflammation, C57BL/6 mice were treated with DRα1-mMOG-35-55. In addition, gene expression profile was analyzed in spinal cords of EAE DR*1501-Tg mice that were treated with DRα1-mMOG-35-55. Results We here demonstrate that DRα1-mMOG-35-55 could effectively treat EAE in MHC-mismatched C57BL/6 mice by reducing CNS inflammation, potentially mediated in part through an increased frequency of M2 monocytes in the spinal cord. Microarray analysis of spinal cord tissue from DRα1-mMOG-35-55-treated vs. vehicle control mice with EAE revealed decreased expression of a large number of pro-inflammatory genes including CD74, NLRP3, and IL-1β and increased expression of genes involved in myelin repair (MBP) and neuroregeneration (HUWE1). Conclusion These findings indicate that the DRα1-mMOG-35-55 construct retains therapeutic, anti-inflammatory, and neuroprotective activities during treatment of EAE across MHC disparate barriers. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0342-4) contains supplementary material, which is available to authorized users.
Collapse
|
13
|
Yang JL, Lin YT, Chuang PC, Bohr VA, Mattson MP. BDNF and exercise enhance neuronal DNA repair by stimulating CREB-mediated production of apurinic/apyrimidinic endonuclease 1. Neuromolecular Med 2014; 16:161-174. [PMID: 24114393 PMCID: PMC3948322 DOI: 10.1007/s12017-013-8270-x] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 09/26/2013] [Indexed: 01/11/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) promotes the survival and growth of neurons during brain development and mediates activity-dependent synaptic plasticity and associated learning and memory in the adult. BDNF levels are reduced in brain regions affected in Alzheimer's, Parkinson's, and Huntington's diseases, and elevation of BDNF levels can ameliorate neuronal dysfunction and degeneration in experimental models of these diseases. Because neurons accumulate oxidative lesions in their DNA during normal activity and in neurodegenerative disorders, we determined whether and how BDNF affects the ability of neurons to cope with oxidative DNA damage. We found that BDNF protects cerebral cortical neurons against oxidative DNA damage-induced death by a mechanism involving enhanced DNA repair. BDNF stimulates DNA repair by activating cyclic AMP response element-binding protein (CREB), which, in turn, induces the expression of apurinic/apyrimidinic endonuclease 1 (APE1), a key enzyme in the base excision DNA repair pathway. Suppression of either APE1 or TrkB by RNA interference abolishes the ability of BDNF to protect neurons against oxidized DNA damage-induced death. The ability of BDNF to activate CREB and upregulate APE1 expression is abolished by shRNA of TrkB as well as inhibitors of TrkB, PI3 kinase, and Akt kinase. Voluntary running wheel exercise significantly increases levels of BDNF, activates CREB, and upregulates APE1 in the cerebral cortex and hippocampus of mice, suggesting a novel mechanism whereby exercise may protect neurons from oxidative DNA damage. Our findings reveal a previously unknown ability of BDNF to enhance DNA repair by inducing the expression of the DNA repair enzyme APE1.
Collapse
Affiliation(s)
- Jenq-Lin Yang
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA; Laboratory of Molecular Gerontology, National Institute on Aging Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA; Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, 123 Ta Pei Road, Kaohsiung 83301, Taiwan
| | - Yu-Ting Lin
- Center for Translation Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, 123 Ta Pei Road, Kaohsiung 83301, Taiwan
| | - Pei-Chin Chuang
- Department of Medical Research, Kaohsiung Chang Gung, Memorial Hospital, 123 Ta Pei Road, Kaohsiung 83301, Taiwan
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| |
Collapse
|
14
|
Interaction of PDK1 with phosphoinositides is essential for neuronal differentiation but dispensable for neuronal survival. Mol Cell Biol 2012; 33:1027-40. [PMID: 23275438 DOI: 10.1128/mcb.01052-12] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
3-Phosphoinositide-dependent protein kinase 1 (PDK1) operates in cells in response to phosphoinositide 3-kinase activation and phosphatidylinositol-3,4,5-trisphosphate [PtdIns(3,4,5)P(3)] production by activating a number of AGC kinases, including protein kinase B (PKB)/Akt. Both PDK1 and PKB contain pleckstrin homology (PH) domains that interact with the PtdIns(3,4,5)P(3) second messenger. Disrupting the interaction of the PDK1 PH domain with phosphoinositides by expressing the PDK1 K465E knock-in mutation resulted in mice with reduced PKB activation. We explored the physiological consequences of this biochemical lesion in the central nervous system. The PDK1 knock-in mice displayed a reduced brain size due to a reduction in neuronal cell size rather than cell number. Reduced BDNF-induced phosphorylation of PKB at Thr308, the PDK1 site, was observed in the mutant neurons, which was not rate limiting for the phosphorylation of those PKB substrates governing neuronal survival and apoptosis, such as FOXO1 or glycogen synthase kinase 3 (GSK3). Accordingly, the integrity of the PDK1 PH domain was not essential to support the survival of different embryonic neuronal populations analyzed. In contrast, PKB-mediated phosphorylation of PRAS40 and TSC2, allowing optimal mTORC1 activation and brain-specific kinase (BRSK) protein synthesis, was markedly reduced in the mutant mice, leading to impaired neuronal growth and differentiation.
Collapse
|
15
|
Wu J, Kharebava G, Piao C, Stoica BA, Dinizo M, Sabirzhanov B, Hanscom M, Guanciale K, Faden AI. Inhibition of E2F1/CDK1 pathway attenuates neuronal apoptosis in vitro and confers neuroprotection after spinal cord injury in vivo. PLoS One 2012; 7:e42129. [PMID: 22848730 PMCID: PMC3405037 DOI: 10.1371/journal.pone.0042129] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 07/03/2012] [Indexed: 11/18/2022] Open
Abstract
Apoptosis of post-mitotic neurons plays a significant role in secondary tissue damage following traumatic spinal cord injury (SCI). Activation of E2F1-dependent transcription promotes expression of pro-apoptotic factors, including CDK1; this signal transduction pathway is believed to represent an important mechanism for the physiological or pathological neuronal cell death. However, a specific role for this pathway in neuronal apoptosis induced by SCI has not yet been reported. Here we demonstrate up-regulation of the E2F1/CDK1 pathway that is associated with neuronal apoptosis following impact SCI in rats. Expression of E2F1 and CDK1 were robustly up-regulated as early as 15 min after injury and sustained until 3 days post-injury. CDK1 activity and E2F1 downstream targets bim and c-Myb were significantly increased after SCI. Activation of E2F1/CDK1 signaling also was associated with death of neurons in vitro; this was attenuated by shRNA knockdown or pharmacological inhibition of the E2F1/CDK1 pathway. CR8, a novel and potent CDK1 inhibitor, blocked apoptosis of primary cortical neurons at low-micromolar concentrations. Moreover, SCI-induced up-regulation of E2F1/CDK1 and associated neuronal apoptosis was significantly attenuated by systemic injection of CR8 (1 mg/kg, i.p.) at 5 min after injury. CR8 significantly decreased posttraumatic elevation of biochemical markers of apoptosis, such as products of caspase-3 and α–fodrin cleavage, as well as neuronal cell death, as indicated by TUNEL staining. Importantly, CR8 treatment also increased the number of surviving neurons at 5 weeks after injury. Together, these findings indicate that activation of the E2F1/CDK1 pathway contributes to the pathophysiology of SCI and that selective inhibition of this signaling cascade may represent an attractive therapeutic strategy.
Collapse
Affiliation(s)
- Junfang Wu
- Department of Anesthesiology & Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, Baltimore, Maryland, United States of America.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Shi GX, Andres DA, Cai W. Ras family small GTPase-mediated neuroprotective signaling in stroke. Cent Nerv Syst Agents Med Chem 2012; 11:114-37. [PMID: 21521171 DOI: 10.2174/187152411796011349] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/18/2011] [Accepted: 03/22/2011] [Indexed: 12/31/2022]
Abstract
Selective neuronal cell death is one of the major causes of neuronal damage following stroke, and cerebral cells naturally mobilize diverse survival signaling pathways to protect against ischemia. Importantly, therapeutic strategies designed to improve endogenous anti-apoptotic signaling appear to hold great promise in stroke treatment. While a variety of complex mechanisms have been implicated in the pathogenesis of stroke, the overall mechanisms governing the balance between cell survival and death are not well-defined. Ras family small GTPases are activated following ischemic insults, and in turn, serve as intrinsic switches to regulate neuronal survival and regeneration. Their ability to integrate diverse intracellular signal transduction pathways makes them critical regulators and potential therapeutic targets for neuronal recovery after stroke. This article highlights the contribution of Ras family GTPases to neuroprotective signaling cascades, including mitogen-activated protein kinase (MAPK) family protein kinase- and AKT/PKB-dependent signaling pathways as well as the regulation of cAMP response element binding (CREB), Forkhead box O (FoxO) and hypoxiainducible factor 1(HIF1) transcription factors, in stroke.
Collapse
Affiliation(s)
- Geng-Xian Shi
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, 741 S. Limestone St., Lexington, KY 40536-0509, USA.
| | | | | |
Collapse
|
17
|
Fenner BM. Truncated TrkB: beyond a dominant negative receptor. Cytokine Growth Factor Rev 2012; 23:15-24. [PMID: 22341689 DOI: 10.1016/j.cytogfr.2012.01.002] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 01/13/2012] [Indexed: 12/14/2022]
Abstract
BDNF activates trkB receptors to regulate neuronal survival, differentiation, and proliferation. Mutations in the BDNF gene, altered BDNF expression, and altered trkB expression are associated with degenerative and psychiatric disorders. The full-length trkB receptor (trkB.tk(+)) undergoes autophosphorylation to activate intracellular signaling pathways. The truncated trkB receptor (trkB.t1) is abundantly expressed in the brain but lacks the catalytic tyrosine kinase domain. TrkB.t1 is a dominant-negative receptor that inhibits trkB.tk(+) signaling. While this is an important function of trkB.t1, it is only one of its many functions. TrkB.t1 sequesters and translocate BDNF, induces filopodia and neurite outgrowth, stimulates intracellular signaling cascades, regulates Rho GTPase signaling, and modifies cytoskeletal structures. TrkB.t1 is an active signaling molecule with regulatory effects on neurons and astrocytes.
Collapse
|
18
|
Xifró X, Anglada-Huguet M, Rué L, Saavedra A, Pérez-Navarro E, Alberch J. Increased 90-kDa ribosomal S6 kinase (Rsk) activity is protective against mutant huntingtin toxicity. Mol Neurodegener 2011; 6:74. [PMID: 22041125 PMCID: PMC3217046 DOI: 10.1186/1750-1326-6-74] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 10/31/2011] [Indexed: 01/03/2023] Open
Abstract
Background The 90-kDa ribosomal S6 kinase (Rsk) family is involved in cell survival. Rsk activation is regulated by sequential phosphorylations controlled by extracellular signal-regulated kinase (ERK) 1/2 and 3-phosphoinositide-dependent protein kinase 1 (PDK1). Altered ERK1/2 and PDK1 phosphorylation have been described in Huntington's disease (HD), characterized by the expression of mutant huntingtin (mhtt) and striatal degeneration. However, the role of Rsk in this neurodegenerative disease remains unknown. Here, we analyzed the protein levels, activity and role of Rsk in in vivo and in vitro HD models. Results We observed increased protein levels of Rsk1 and Rsk2 in the striatum of HdhQ111/Q111 and R6/1 mice, STHdhQ111/Q111 cells and striatal cells transfected with full-length mhtt. Analysis of the phosphorylation of Rsk in Hdh mice and STHdh cells showed reduced levels of phospho Ser-380 (dependent on ERK1/2), whereas phosphorylation at Ser-221 (dependent on PDK1) was increased. Moreover, we found that elevated Rsk activity in STHdhQ111/Q111 cells was mainly due to PDK1 activity, as assessed by transfection with Rsk mutant constructs. The increase of Rsk in STHdhQ111/Q111 cells occurred in the cytosol and in the nucleus, which results in enhanced phosphorylation of both cytosolic and nuclear Rsk targets. Finally, pharmacological inhibition of Rsk, knock-down and overexpression experiments indicated that Rsk activity exerts a protective effect against mhtt-induced cell death in STHdhQ7/Q7 cells transfected with mhtt. Conclusion The increase of Rsk levels and activity would act as a compensatory mechanism with capacity to prevent mhtt-mediated cell death. We propose Rsk as a good target for neuroprotective therapies in HD.
Collapse
Affiliation(s)
- Xavier Xifró
- Departament de Biologia Cel·lular, Immunologia i Neurociències, Facultat de Medicina, Universitat de Barcelona, Spain
| | | | | | | | | | | |
Collapse
|
19
|
Guo Y, Johnson EC, Cepurna WO, Dyck JA, Doser T, Morrison JC. Early gene expression changes in the retinal ganglion cell layer of a rat glaucoma model. Invest Ophthalmol Vis Sci 2011; 52:1460-73. [PMID: 21051717 DOI: 10.1167/iovs.10-5930] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To identify patterns of early gene expression changes in the retinal ganglion cell layer (GCL) of a rodent model of chronic glaucoma. METHODS Prolonged elevation of intraocular pressure (IOP) was produced in rats by episcleral vein injection of hypertonic saline (N = 30). GCLs isolated by laser capture microdissection were grouped by grading of the nerve injury (<25% axon degeneration for early injury; >25% for advanced injury). Gene expression was determined by cDNA microarray of independent GCL RNA samples. Quantitative PCR (qPCR) was used to further examine the expression of selected genes. RESULTS By array analysis, 533 GCL genes (225 up, 308 down) were significantly regulated in early injury. Compared to only one major upregulated gene class of metabolism regulation, more were downregulated, including mitochondria, ribosome, proteasome, energy pathways, protein synthesis, protein folding, and synaptic transmission. qPCR confirmed an early upregulation of Atf3. With advanced injury, 1790 GCL genes were significantly regulated (997 up, 793 down). Altered gene categories included upregulated protein synthesis, immune response, and cell apoptosis and downregulated dendrite morphogenesis and axon extension. Of all the early changed genes, 50% were not present in advanced injury. These uniquely affected genes were mainly associated with upregulated transcription regulation and downregulated protein synthesis. CONCLUSIONS Early GCL gene responses to pressure-induced injury are characterized by an upregulation of Atf3 and extensive downregulation in genes associated with cellular metabolism and neuronal functions. Most likely, these changes represent those specific to RGCs and are thus potentially important for enhancing RGC survival in glaucoma.
Collapse
Affiliation(s)
- Ying Guo
- Kenneth C. Swan Ocular Neurobiology Laboratory, Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | | | | | | | | | | |
Collapse
|
20
|
A humanin derivative reduces amyloid beta accumulation and ameliorates memory deficit in triple transgenic mice. PLoS One 2011; 6:e16259. [PMID: 21264226 PMCID: PMC3022031 DOI: 10.1371/journal.pone.0016259] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 12/08/2010] [Indexed: 12/18/2022] Open
Abstract
Humanin (HN), a 24-residue peptide, was identified as a novel neuroprotective factor and shows anti-cell death activity against a wide spectrum of Alzheimer's disease (AD)-related cytotoxicities, including exposure to amyloid beta (Abeta), in vitro. We previously demonstrated that the injection of S14G-HN, a highly potent HN derivative, into brain ameliorated memory loss in an Abeta-injection mouse model. To fully understand HN's functions under AD-associated pathological conditions, we examined the effect of S14G-HN on triple transgenic mice harboring APPswe, tauP310L, and PS-1M146V that show the age-dependent development of multiple pathologies relating to AD. After 3 months of intranasal treatment, behavioral analyses showed that S14G-HN ameliorated cognitive impairment in male mice. Moreover, ELISA and immunohistochemical analyses showed that Abeta levels in brains were markedly lower in S14G-HN-treated male and female mice than in vehicle control mice. We also found the expression level of neprilysin, an Abeta degrading enzyme, in the outer molecular layer of hippocampal formation was increased in S14G-HN-treated mouse brains. NEP activity was also elevated by S14G-HN treatment in vitro. These findings suggest that decreased Abeta level in these mice is at least partly attributed to S14G-HN-induced increase of neprilysin level. Although HN was identified as an anti-neuronal death factor, these results indicate that HN may also have a therapeutic effect on amyloid accumulation in AD.
Collapse
|
21
|
Shi ZD, Abraham G, Tarbell JM. Shear stress modulation of smooth muscle cell marker genes in 2-D and 3-D depends on mechanotransduction by heparan sulfate proteoglycans and ERK1/2. PLoS One 2010; 5:e12196. [PMID: 20808940 PMCID: PMC2922372 DOI: 10.1371/journal.pone.0012196] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 07/25/2010] [Indexed: 01/31/2023] Open
Abstract
Background During vascular injury, vascular smooth muscle cells (SMCs) and fibroblasts/myofibroblasts (FBs/MFBs) are exposed to altered luminal blood flow or transmural interstitial flow. We investigate the effects of these two types of fluid flows on the phenotypes of SMCs and MFBs and the underlying mechanotransduction mechanisms. Methodology/Principal Findings Exposure to 8 dyn/cm2 laminar flow shear stress (2-dimensional, 2-D) for 15 h significantly reduced expression of α-smooth muscle actin (α-SMA), smooth muscle protein 22 (SM22), SM myosin heavy chain (SM-MHC), smoothelin, and calponin. Cells suspended in collagen gels were exposed to interstitial flow (1 cmH2O, ∼0.05 dyn/cm2, 3-D), and after 6 h of exposure, expression of SM-MHC, smoothelin, and calponin were significantly reduced, while expression of α-SMA and SM22 were markedly enhanced. PD98059 (an ERK1/2 inhibitor) and heparinase III (an enzyme to cleave heparan sulfate) significantly blocked the effects of laminar flow on gene expression, and also reversed the effects of interstitial flow on SM-MHC, smoothelin, and calponin, but enhanced interstitial flow-induced expression of α-SMA and SM22. SMCs and MFBs have similar responses to fluid flow. Silencing ERK1/2 completely blocked the effects of both laminar flow and interstitial flow on SMC marker gene expression. Western blotting showed that both types of flows induced ERK1/2 activation that was inhibited by disruption of heparan sulfate proteoglycans (HSPGs). Conclusions/Significance The results suggest that HSPG-mediated ERK1/2 activation is an important mechanotransduction pathway modulating SMC marker gene expression when SMCs and MFBs are exposed to flow. Fluid flow may be involved in vascular remodeling and lesion formation by affecting phenotypes of vascular wall cells. This study has implications in understanding the flow-related mechanobiology in vascular lesion formation, tumor cell invasion, and stem cell differentiation.
Collapse
Affiliation(s)
- Zhong-Dong Shi
- Department of Biomedical Engineering, The City College of New York, The City University of New York (CUNY), New York, New York, United States of America
- * E-mail: (ZDS); (JMT)
| | - Giya Abraham
- Department of Biomedical Engineering, The City College of New York, The City University of New York (CUNY), New York, New York, United States of America
| | - John M. Tarbell
- Department of Biomedical Engineering, The City College of New York, The City University of New York (CUNY), New York, New York, United States of America
- * E-mail: (ZDS); (JMT)
| |
Collapse
|
22
|
Shi ZD, Ji XY, Berardi DE, Qazi H, Tarbell JM. Interstitial flow induces MMP-1 expression and vascular SMC migration in collagen I gels via an ERK1/2-dependent and c-Jun-mediated mechanism. Am J Physiol Heart Circ Physiol 2009; 298:H127-35. [PMID: 19880665 DOI: 10.1152/ajpheart.00732.2009] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The migration of vascular smooth muscle cells (SMCs) and fibroblasts into the intima after vascular injury is a central process in vascular lesion formation. The elevation of transmural interstitial flow is also observed after damage to the vascular endothelium. We have previously shown that interstitial flow upregulates matrix metalloproteinase-1 (MMP-1) expression, which in turn promotes SMC and fibroblast migration in collagen I gels. In this study, we investigated further the mechanism of flow-induced MMP-1 expression. An ERK1/2 inhibitor PD-98059 completely abolished interstitial flow-induced SMC migration and MMP-1 expression. Interstitial flow promoted ERK1/2 phosphorylation, whereas PD-98059 abolished flow-induced activation. Silencing ERK1/2 completely abolished MMP-1 expression and SMC migration. In addition, interstitial flow increased the expression of activator protein-1 transcription factors (c-Jun and c-Fos), whereas PD-98059 attenuated flow-induced expression. Knocking down c-jun completely abolished flow-induced MMP-1 expression, whereas silencing c-fos did not affect MMP-1 expression. Taken together, our data indicate that interstitial flow induces MMP-1 expression and SMC migration in collagen I gels via an ERK1/2-dependent and c-Jun-mediated mechanism and suggest that interstitial flow, ERK1/2 MAPK, c-Jun, and MMP-1 may play important roles in SMC migration and neointima formation after vascular injury.
Collapse
Affiliation(s)
- Zhong-Dong Shi
- City College of New York, City University of New York, Department of Biomedical Engineering, New York, NY 10031, USA.
| | | | | | | | | |
Collapse
|
23
|
Thiele CJ, Li Z, McKee AE. On Trk--the TrkB signal transduction pathway is an increasingly important target in cancer biology. Clin Cancer Res 2009; 15:5962-7. [PMID: 19755385 DOI: 10.1158/1078-0432.ccr-08-0651] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the beginning, Trk was an oncogene. Yet Neurotrophin-Trk signaling came to preeminence in the field of neurobiology. Now it is appreciated that Trks regulate important processes in nonneuronal cells and, in addition to their impact on tumors of neural origin, may contribute to the pathogenesis of carcinomas, myelomas, and prostate and lymphoid tumors. Although mutations and rearrangements of Trk are seen only sporadically in human cancers, such as medullary thyroid carcinoma, a number of recent studies indicate that expression of TrkB contributes to tumor pathology. In neuroblastoma, TrkA expression marks good prognosis which TrkB and Brain-derived neurotrophic factor (BDNF) expression marks poor prognosis. Activation of the BDNF/TrkB signal transduction pathway also stimulates tumor cell survival and angiogenesis and contributes to resistance to cytotoxic drugs and anoikis, enabling cells to acquire many of the characteristic features required for tumorigenesis. Small molecule inhibitors, such as Cephalon's CEP-701, are in phase 1 and 2 clinical trials, and a series of AstraZeneca Trk inhibitors are poised to enter the clinic. As monotherapy, inhibitors may be effective only in tumors with activating Trk mutations. Important clinical follow-up will be the assessment of Trk inhibitors in combination with standard chemo- or radiotherapy or other signal transduction pathway inhibitors.
Collapse
Affiliation(s)
- Carol J Thiele
- Cell and Molecular Biology Section, Pediatric Oncology Branch, Center for Cancer Research, CRC, NCI, Bethesda, Maryland 20892, USA.
| | | | | |
Collapse
|
24
|
Iwanami A, Cloughesy TF, Mischel PS. Striking the balance between PTEN and PDK1: it all depends on the cell context. Genes Dev 2009; 23:1699-704. [PMID: 19651981 DOI: 10.1101/gad.1832909] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The phosphatidyl-inosital-3 kinase (PI3K) signaling pathway is critical for normal brain development and function and is commonly hyperactivated in brain cancer. The PTEN (phosphatase and tensin homolog deleted on chromosome 10) tumor suppressor protein and phosphate-depended kinase 1 (PDK-1) are critical regulators of this pathway. In the July 15, 2009, issue of Genes & Development, Chalhoub and colleagues (pp. 1619-1624) demonstrate PDK1-dependent and PDK1-independent effects of conditional PTEN deletion in the brain, and they identify cell type-specific differences in feedback regulation of the PI3K pathway. These studies provide important insights as to how neurons and glia may differentially regulate PI3K signaling, yielding intriguing clues about targeting PTEN-deficient brain cancers.
Collapse
Affiliation(s)
- Akio Iwanami
- Department of Pathology and Laboratory Medicine, the Henry Singleton Brain Tumor Program at the David Geffen University of California at Los Angeles School of Medicine, Los Angeles, California 90095, USA
| | | | | |
Collapse
|
25
|
Jantas D, Szymanska M, Budziszewska B, Lason W. An involvement of BDNF and PI3-K/Akt in the anti-apoptotic effect of memantine on staurosporine-evoked cell death in primary cortical neurons. Apoptosis 2009; 14:900-12. [DOI: 10.1007/s10495-009-0370-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|