1
|
Starr A, Nickoloff-Bybel E, Abedalthaqafi R, Albloushi N, Jordan-Sciutto KL. Human iPSC-derived neurons reveal NMDAR-independent dysfunction following HIV-associated insults. Front Mol Neurosci 2024; 16:1353562. [PMID: 38348237 PMCID: PMC10859444 DOI: 10.3389/fnmol.2023.1353562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 12/30/2023] [Indexed: 02/15/2024] Open
Abstract
The central nervous system encounters a number of challenges following HIV infection, leading to increased risk for a collection of neurocognitive symptoms clinically classified as HIV-associated neurocognitive disorders (HAND). Studies attempting to identify causal mechanisms and potential therapeutic interventions have historically relied on primary rodent neurons, but a number of recent reports take advantage of iPSC-derived neurons in order to study these mechanisms in a readily reproducible, human model. We found that iPSC-derived neurons differentiated via an inducible neurogenin-2 transcription factor were resistant to gross toxicity from a number of HIV-associated insults previously reported to be toxic in rodent models, including HIV-infected myeloid cell supernatants and the integrase inhibitor antiretroviral drug, elvitegravir. Further examination of these cultures revealed robust resistance to NMDA receptor-mediated toxicity. We then performed a comparative analysis of iPSC neurons exposed to integrase inhibitors and activated microglial supernatants to study sub-cytotoxic alterations in micro electrode array (MEA)-measured neuronal activity and gene expression, identifying extracellular matrix interaction/morphogenesis as the most consistently altered pathways across HIV-associated insults. These findings illustrate that HIV-associated insults dysregulate human neuronal activity and organization even in the absence of gross NMDA-mediated neurotoxicity, which has important implications on the effects of these insults in neurodevelopment and on the interpretation of primary vs. iPSC in vitro neuronal studies.
Collapse
Affiliation(s)
| | | | | | | | - Kelly L. Jordan-Sciutto
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
2
|
Luo M, Yi Y, Huang S, Dai S, Xie L, Liu K, Zhang S, Jiang T, Wang T, Yao B, Wang H, Xu D. Gestational dexamethasone exposure impacts hippocampal excitatory synaptic transmission and learning and memory function with transgenerational effects. Acta Pharm Sin B 2023; 13:3708-3727. [PMID: 37719378 PMCID: PMC10501875 DOI: 10.1016/j.apsb.2023.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/20/2023] [Accepted: 05/06/2023] [Indexed: 09/19/2023] Open
Abstract
The formation of learning and memory is regulated by synaptic plasticity in hippocampal neurons. Here we explored how gestational exposure to dexamethasone, a synthetic glucocorticoid commonly used in clinical practice, has lasting effects on offspring's learning and memory. Adult offspring rats of prenatal dexamethasone exposure (PDE) displayed significant impairments in novelty recognition and spatial learning memory, with some phenotypes maintained transgenerationally. PDE impaired synaptic transmission of hippocampal excitatory neurons in offspring of F1 to F3 generations, and abnormalities of neurotransmitters and receptors would impair synaptic plasticity and lead to impaired learning and memory, but these changes failed to carry over to offspring of F5 and F7 generations. Mechanistically, altered hippocampal miR-133a-3p-SIRT1-CDK5-NR2B signaling axis in PDE multigeneration caused inhibition of excitatory synaptic transmission, which might be related to oocyte-specific high expression and transmission of miR-133a-3p. Together, PDE affects hippocampal excitatory synaptic transmission, with lasting consequences across generations, and CDK5 in offspring's peripheral blood might be used as an early-warning marker for fetal-originated learning and memory impairment.
Collapse
Affiliation(s)
- Mingcui Luo
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Yiwen Yi
- Department of Pharmacology, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Songqiang Huang
- Department of Pharmacology, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Shiyun Dai
- Department of Pharmacology, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Lulu Xie
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
- Department of Pediatrics, Renmin Hospital of Wuhan University, Wuhan 430071, China
| | - Kexin Liu
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
- Department of Pharmacy, Zhongnan Hospital of Wuhan University, Wuhan 430071, China
| | - Shuai Zhang
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Tao Jiang
- Department of Pharmacology, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Tingting Wang
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Baozhen Yao
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
- Department of Pediatrics, Renmin Hospital of Wuhan University, Wuhan 430071, China
| | - Hui Wang
- Department of Pharmacology, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| | - Dan Xu
- Department of Obstetrics, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China
| |
Collapse
|
3
|
Saxena SK, Sharma D, Kumar S, Puri B. Understanding HIV-associated neurocognitive and neurodegenerative disorders (neuroAIDS): enroute to achieve the 95-95-95 target and sustainable development goal for HIV/AIDS response. Virusdisease 2023; 34:165-171. [PMID: 37408553 PMCID: PMC10317939 DOI: 10.1007/s13337-023-00830-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2023] [Indexed: 07/07/2023] Open
Abstract
The world's sustained commitment to the HIV/AIDS response and to reaching the 2030 Sustainable Development Goal (SDG) of "ending AIDS" as a public health issue is indicated by the ambitious 95-95-95 targets for all relevant populations. Neurological conditions of AIDS (neuroAIDS) are the most significant and severe central nervous system complication associated with HIV infection in which viral antigens can enter in the brain by breaching the blood brain barrier and cause dementia, neuroinflammation and encephalopathy. The prevalence of neuroAIDS is 10-50% in people with advanced HIV disease, whereas 5-25% in people on ART. Currently, MRI, CT and other tools are used to diagnose the neuroAIDS/ HIV-associated dementia and antiretroviral therapy is widely used to treat the neuroAIDS. In spite of many advanced tools and pathogenesis of neuroAIDS, developing therapeutics remains a formidable challenge. Long acting cabotegravir type of therapeutics is an advanced stage of research which shows good results for the treatment of neuroAIDS. Therefore, here we are discussing the recent insights of the pathogenesis, possible therapeutics and current strategies and treatment to overcome the neuroAIDS.
Collapse
Affiliation(s)
- Shailendra K. Saxena
- Centre for Advanced Research (CFAR), Faculty of Medicine, King George’s Medical University (KGMU), Lucknow, 226003 India
- World Society for Virology (WSV), Northampton, Massachusetts USA
- The Indian Virological Society (IVS), New Delhi, India
| | - Deepak Sharma
- Centre for Advanced Research (CFAR), Faculty of Medicine, King George’s Medical University (KGMU), Lucknow, 226003 India
| | - Swatantra Kumar
- Centre for Advanced Research (CFAR), Faculty of Medicine, King George’s Medical University (KGMU), Lucknow, 226003 India
- World Society for Virology (WSV), Northampton, Massachusetts USA
| | - Bipin Puri
- Centre for Advanced Research (CFAR), Faculty of Medicine, King George’s Medical University (KGMU), Lucknow, 226003 India
| |
Collapse
|
4
|
Lopez Lloreda C, Chowdhury S, Ghura S, Alvarez-Periel E, Jordan-Sciutto K. HIV-Associated Insults Modulate ADAM10 and Its Regulator Sirtuin1 in an NMDA Receptor-Dependent Manner. Cells 2022; 11:cells11192962. [PMID: 36230925 PMCID: PMC9564041 DOI: 10.3390/cells11192962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/14/2022] [Accepted: 09/19/2022] [Indexed: 12/02/2022] Open
Abstract
Neurologic deficits associated with human immunodeficiency virus (HIV) infection impact about 50% of persons with HIV (PWH). These disorders, termed HIV-associated neurocognitive disorders (HAND), possess neuropathologic similarities to Alzheimer’s disease (AD), including intra- and extracellular amyloid-beta (Aβ) peptide aggregates. Aβ peptide is produced through cleavage of the amyloid precursor protein (APP) by the beta secretase BACE1. However, this is precluded by cleavage of APP by the non-amyloidogenic alpha secretase, ADAM10. Previous studies have found that BACE1 expression was increased in the CNS of PWH with HAND as well as animal models of HAND. Further, BACE1 contributed to neurotoxicity. Yet in in vitro models, the role of ADAM10 and its potential regulatory mechanisms had not been examined. To address this, primary rat cortical neurons were treated with supernatants from HIV-infected human macrophages (HIV/MDMs). We found that HIV/MDMs decreased levels of both ADAM10 and Sirtuin1 (SIRT1), a regulator of ADAM10 that is implicated in aging and in AD. Both decreases were blocked with NMDA receptor antagonists, and treatment with NMDA was sufficient to induce reduction in ADAM10 and SIRT1 protein levels. Furthermore, decreases in SIRT1 protein levels were observed at an earlier time point than the decreases in ADAM10 protein levels, and the reduction in SIRT1 was reversed by proteasome inhibitor MG132. This study indicates that HIV-associated insults, particularly excitotoxicity, contribute to changes of APP secretases by downregulating levels of ADAM10 and its regulator.
Collapse
Affiliation(s)
- Claudia Lopez Lloreda
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sarah Chowdhury
- College of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shivesh Ghura
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elena Alvarez-Periel
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kelly Jordan-Sciutto
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Correspondence:
| |
Collapse
|
5
|
Machine Learning-Based Virtual Screening for the Identification of Cdk5 Inhibitors. Int J Mol Sci 2022; 23:ijms231810653. [PMID: 36142566 PMCID: PMC9502400 DOI: 10.3390/ijms231810653] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 12/04/2022] Open
Abstract
Cyclin-dependent kinase 5 (Cdk5) is an atypical proline-directed serine/threonine protein kinase well-characterized for its role in the central nervous system rather than in the cell cycle. Indeed, its dysregulation has been strongly implicated in the progression of synaptic dysfunction and neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), and also in the development and progression of a variety of cancers. For this reason, Cdk5 is considered as a promising target for drug design, and the discovery of novel small-molecule Cdk5 inhibitors is of great interest in the medicinal chemistry field. In this context, we employed a machine learning-based virtual screening protocol with subsequent molecular docking, molecular dynamics simulations and binding free energy evaluations. Our virtual screening studies resulted in the identification of two novel Cdk5 inhibitors, highlighting an experimental hit rate of 50% and thus validating the reliability of the in silico workflow. Both identified ligands, compounds CPD1 and CPD4, showed a promising enzyme inhibitory activity and CPD1 also demonstrated a remarkable antiproliferative activity in ovarian and colon cancer cells. These ligands represent a valuable starting point for structure-based hit-optimization studies aimed at identifying new potent Cdk5 inhibitors.
Collapse
|
6
|
Abstract
Cdk5 is a proline-directed serine/threonine protein kinase that governs a variety of cellular processes in neurons, the dysregulation of which compromises normal brain function. The mechanisms underlying the modulation of Cdk5, its modes of action, and its effects on the nervous system have been a great focus in the field for nearly three decades. In this review, we provide an overview of the discovery and regulation of Cdk5, highlighting recent findings revealing its role in neuronal/synaptic functions, circadian clocks, DNA damage, cell cycle reentry, mitochondrial dysfunction, as well as its non-neuronal functions under physiological and pathological conditions. Moreover, we discuss evidence underscoring aberrant Cdk5 activity as a common theme observed in many neurodegenerative diseases.
Collapse
Affiliation(s)
- Ping-Chieh Pao
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Li-Huei Tsai
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| |
Collapse
|
7
|
Pharmacological relevance of CDK inhibitors in Alzheimer's disease. Neurochem Int 2021; 148:105115. [PMID: 34182065 DOI: 10.1016/j.neuint.2021.105115] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 12/11/2022]
Abstract
Evidence suggests that cell cycle activation plays a role in the pathophysiology of neurodegenerative diseases. Alzheimer's disease is a progressive, terminal neurodegenerative disease that affects memory and other important mental functions. Intracellular deposition of Tau protein, a hyperphosphorylated form of a microtubule-associated protein, and extracellular aggregation of Amyloid β protein, which manifests as neurofibrillary tangles (NFT) and senile plaques, respectively, characterize this condition. In recent years, however, several studies have concluded that cell cycle re-entry is one of the key causes of neuronal death in the pathogenesis of Alzheimer's disease. The eukaryotic cell cycle is well-coordinated machinery that performs critical functions in cell replenishment, such as DNA replication, cell creation, repair, and the birth of new daughter cells from the mother cell. The complex interplay between the levels of various cyclins and cyclin-dependent kinases (CDKs) at different checkpoints is needed for cell cycle synchronization. CDKIs (cyclin-dependent kinase inhibitors) prevent cyclin degradation and CDK inactivation. Different external and internal factors regulate them differently, and they have different tissue expression and developmental functions. The checkpoints ensure that the previous step is completed correctly before starting the new cell cycle phase, and they protect against the transfer of defects to the daughter cells. Due to the development of more selective and potent ATP-competitive CDK inhibitors, CDK inhibitors appear to be on the verge of having a clinical impact. This avenue is likely to yield new and effective medicines for the treatment of cancer and other neurodegenerative diseases. These new methods for recognizing CDK inhibitors may be used to create non-ATP-competitive agents that target CDK4, CDK5, and other CDKs that have been recognized as important therapeutic targets in Alzheimer's disease treatment.
Collapse
|
8
|
Posada-Duque RA, Cardona-Gómez GP. CDK5 Targeting as a Therapy for Recovering Neurovascular Unit Integrity in Alzheimer's Disease. J Alzheimers Dis 2020; 82:S141-S161. [PMID: 33016916 DOI: 10.3233/jad-200730] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The neurovascular unit (NVU) is responsible for synchronizing the energetic demand, vasodynamic changes, and neurochemical and electrical function of the brain through a closed and interdependent interaction of cell components conforming to brain tissue. In this review, we will focus on cyclin-dependent kinase 5 (CDK5) as a molecular pivot, which plays a crucial role in the healthy function of neurons, astrocytes, and the endothelium and is implicated in the cross-talk of cellular adhesion signaling, ion transmission, and cytoskeletal remodeling, thus allowing the individual and interconnected homeostasis of cerebral parenchyma. Then, we discuss how CDK5 overactivation affects the integrity of the NVU in Alzheimer's disease (AD) and cognitive impairment; we emphasize how CDK5 is involved in the excitotoxicity spreading of glutamate and Ca2+ imbalance under acute and chronic injury. Additionally, we present pharmacological and gene therapy strategies for producing partial depletion of CDK5 activity on neurons, astrocytes, or endothelium to recover neuroplasticity and neurotransmission, suggesting that the NVU should be the targeted tissue unit in protective strategies. Finally, we conclude that CDK5 could be effective due to its intervention on astrocytes by its end feet on the endothelium and neurons, acting as an intermediary cell between systemic and central communication in the brain. This review provides integrated guidance regarding the pathogenesis of and potential repair strategies for AD.
Collapse
Affiliation(s)
- Rafael Andrés Posada-Duque
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, SIU, University of Antioquia, Medellín, Colombia.,Institute of Biology, Faculty of Exact and Natural Sciences, University of Antioquia, Medellín, Colombia
| | - Gloria Patricia Cardona-Gómez
- Cellular and Molecular Neurobiology Area, Group of Neuroscience of Antioquia, SIU, University of Antioquia, Medellín, Colombia
| |
Collapse
|
9
|
Forster YM, Green JL, Khatiwada A, Liberato JL, Narayana Reddy PA, Salvino JM, Bienz S, Bigler L, dos Santos WF, Karklin Fontana AC. Elucidation of the Structure and Synthesis of Neuroprotective Low Molecular Mass Components of the Parawixia bistriata Spider Venom. ACS Chem Neurosci 2020; 11:1573-1596. [PMID: 32343555 DOI: 10.1021/acschemneuro.0c00007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The South American social spider Parawixia bistriata produces a venom containing complex organic compounds with intriguing biological activities. The crude venom leads to paralysis in termites and stimulates l-glutamate uptake and inhibits GABA uptake in rat brain synaptosomes. Glutamate is the major neurotransmitter at the insect neuromuscular junction and at the mammalian central nervous system, suggesting a modulation of the glutamatergic system by the venom. Parawixin1, 2, and 10 (Pwx1, 2 and 10) are HPLC fractions that demonstrate this bioactivity. Pwx1 stimulates l-glutamate uptake through the main transporter in the brain, EAAT2, and is neuroprotective in in vivo glaucoma models. Pxw2 inhibits GABA and glycine uptake in synaptosomes and inhibits seizures and neurodegeneration, and Pwx10 increases l-glutamate uptake in synaptosomes and is neuroprotective and anticonvulsant, shown in in vivo epilepsy models. Herein, we investigated the low molecular mass compounds in this venom and have found over 20 small compounds and 36 unique acylpolyamines with and without amino acid linkers. The active substances in fractions Pwx1 and Pwx2 require further investigation. We elucidated and confirmed the structure of the active acylpolyamine in Pwx10. Both fraction Pwx10 and the synthesized component enhance the activity of transporters EAAT1 and EAAT2, and, importantly, offer in vitro neuroprotection against excitotoxicity in primary cultures. These data suggest that compounds with this mechanism could be developed into therapies for disorders in which l-glutamate excitotoxicity is involved.
Collapse
Affiliation(s)
- Yvonne M. Forster
- Department of Chemistry, University of Zurich, Zurich, CH 8057, Switzerland
| | - Jennifer Leigh Green
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Apeksha Khatiwada
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - José Luiz Liberato
- Department of Biology, University of São Paulo, Ribeirão Preto, SP 14040-900, Brazil
| | | | - Joseph M. Salvino
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
| | - Stefan Bienz
- Department of Chemistry, University of Zurich, Zurich, CH 8057, Switzerland
| | - Laurent Bigler
- Department of Chemistry, University of Zurich, Zurich, CH 8057, Switzerland
| | | | - Andréia Cristina Karklin Fontana
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| |
Collapse
|
10
|
Falcucci RM, Wertz R, Green JL, Meucci O, Salvino J, Fontana ACK. Novel Positive Allosteric Modulators of Glutamate Transport Have Neuroprotective Properties in an in Vitro Excitotoxic Model. ACS Chem Neurosci 2019; 10:3437-3453. [PMID: 31257852 DOI: 10.1021/acschemneuro.9b00061] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Dysfunction of excitatory amino acid transporters (EAATs) has been implicated in the pathogenesis of various neurological disorders, such as stroke, brain trauma, epilepsy, and several neurodegenerative disorders. EAAT2 is the main transporter subtype responsible for glutamate clearance in the brain, and plays a key role in regulating neurotransmission and preventing excitotoxicity. Therefore, compounds that increase the activity of EAAT2 have therapeutic potential for neuroprotection. In previous studies, we used virtual screening approaches to identify novel positive allosteric modulators (PAMs) of EAAT2. These compounds were shown to selectively increase the activity of EAAT2 and increase Vmax of transport, without changing substrate affinity. In this work, our major effort was to investigate whether increasing the activity of EAAT2 by allosteric modulation would translate to neuroprotection in in vitro primary culture models of excitotoxicity. To investigate potential neuroprotective effects of one EAAT2 PAM, GT949, we subjected cultures to acute and prolonged excitotoxic insults by exogenous application of glutamate, or oxidative stress by application of hydrogen peroxide. GT949 administration did not result in neuroprotection in the oxidative stress model, likely due to damage of the glutamate transporters. However, GT949 displayed neuroprotective properties after acute and prolonged glutamate-mediated excitotoxicity. We propose that this compound prevents excess glutamate signaling by increasing the rate of glutamate clearance by EAAT2, thereby preventing excitotoxic damage and cell death. This novel class of compounds is therefore an innovative approach for neuroprotection with potential for translation in in vivo animal models of excitotoxicity.
Collapse
Affiliation(s)
- Romulo Martelli Falcucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Ryan Wertz
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Jennifer Leigh Green
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Olimpia Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| | - Joseph Salvino
- The Wistar Institute, Philadelphia, Pennsylvania 19104, United States
| | - Andréia Cristina Karklin Fontana
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, United States
| |
Collapse
|
11
|
Ozturk T, Kollhoff A, Anderson AM, Christina Howell J, Loring DW, Waldrop-Valverde D, Franklin D, Letendre S, Tyor WR, Hu WT. Linked CSF reduction of phosphorylated tau and IL-8 in HIV associated neurocognitive disorder. Sci Rep 2019; 9:8733. [PMID: 31217522 PMCID: PMC6584499 DOI: 10.1038/s41598-019-45418-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 06/06/2019] [Indexed: 12/12/2022] Open
Abstract
HIV-associated neurocognitive disorder (HAND) is a common condition in both developed and developing nations, but its cause is largely unknown. Previous research has inconsistently linked Alzheimer’s disease (AD), viral burden, and inflammation to the onset of HAND in HIV-infected individuals. Here we simultaneously measured cerebrospinal fluid (CSF) levels of established amyloid and tau biomarkers for AD, viral copy numbers, and six key cytokines in 41 HIV-infected individuals off combination anti-retroviral therapy (14 with HAND) who underwent detailed clinical and neuropsychological characterization, and compared their CSF patterns with those from young healthy subjects, older healthy subjects with normal cognition, and older people with AD. HAND was associated with the lowest CSF levels of phosphorylated tau (p-Tau181) after accounting for age and race. We also found very high CSF levels of the pro-inflammatory interferon gamma-induced protein 10 (IP-10/CXCL10) in HIV regardless of cognition, but elevated CSF interleukin 8 (IL-8/CXCL8) only in HIV-NC but not HAND. Eleven HIV-infected subjects underwent repeat CSF collection six months later and showed strongly correlated longitudinal changes in p-Tau181 and IL-8 levels (R = 0.841). These data suggest reduced IL-8 relative to IP-10 and reduced p-Tau181 to characterize HAND.
Collapse
Affiliation(s)
- Tugba Ozturk
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.,Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Alexander Kollhoff
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.,Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - Albert M Anderson
- Department of Medicine - Division of Infectious Disease, Emory University School of Medicine, Atlanta, GA, USA.
| | - J Christina Howell
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.,Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA, USA
| | - David W Loring
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Drenna Waldrop-Valverde
- Center for Neurocognitive Studies, Emory University Hodgson Woodruff School of Nursing, Atlanta, GA, USA
| | - Donald Franklin
- HIV Neurobehavioral Research Center, University of California, San Diego, CA, USA
| | - Scott Letendre
- HIV Neurobehavioral Research Center, University of California, San Diego, CA, USA
| | - William R Tyor
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.,Atlanta Veterans Affairs Medical Center, Decatur, GA, USA
| | - William T Hu
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA. .,Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA, USA.
| |
Collapse
|
12
|
Becerra-Calixto A, Posada-Duque R, Cardona-Gómez GP. Recovery of Neurovascular Unit Integrity by CDK5-KD Astrocyte Transplantation in a Global Cerebral Ischemia Model. Mol Neurobiol 2018; 55:8563-8585. [PMID: 29564811 DOI: 10.1007/s12035-018-0992-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/06/2018] [Indexed: 12/16/2022]
Abstract
Astrocytes play metabolic and structural support roles and contribute to the integrity of the blood-brain barrier (BBB), linking communication between neurons and the endothelium. Cyclin-dependent kinase 5 (CDK5) likely exerts a dual effect on the endothelium and astrocytes due to its involvement in migration and angiogenesis; the overactivation of CDK5 is associated with dysfunction in glutamate recapture and hypoxia. Recently, we proposed that CDK5-targeted astrocytes facilitate the recovery of neurological and motor function in transplanted ischemic rats. In the current study, we treated cerebral ischemic rats and endothelial cells exposed to glutamate toxicity with CDK5 knock-down (CDK5-KD) astrocytes to determine the role of CDK5 in neurovascular integrity. We found that the effects of CDK5-KD were sustained for 4 months, preventing neuronal and astrocyte loss, facilitating the recovery of the BBB via the production of BDNF by endogenous astrocytes (GFP-) surrounding vessels in the motor cortex and the corpus callosum of global ischemic rats, and improving neurological performance. These findings were supported by the in vitro findings of increased transendothelial resistance, p120-ctn+ adhesion and reduced intercellular gaps induced by a CDK5 inhibitor (roscovitine) in bEnd.3 cells in a glutamate-toxicity model. Additionally, CDK5-KD astrocytes in co-culture protected the endothelial cell viability, increased BDNF release from astrocytes, increased BDNF immunoreactivity in neighboring astrocytes and endothelial cells and enhanced cell adhesion in a glutamate-toxicity model. Altogether, these findings suggest that a CDK5 reduction in astrocytes protects the endothelium, which promotes BDNF release, endothelial adhesion, and the recovery of neurovascular unit integrity and brain function in ischemic rats.
Collapse
Affiliation(s)
- Andrea Becerra-Calixto
- Neuroscience Group of Antioquia, Cellular and Molecular Neurobiology Area, Faculty of Medicine, SIU, University of Antioquia, Calle 70, No. 52-21, Medellin, Colombia
| | - Rafael Posada-Duque
- Neuroscience Group of Antioquia, Cellular and Molecular Neurobiology Area, Faculty of Medicine, SIU, University of Antioquia, Calle 70, No. 52-21, Medellin, Colombia.,Institute of Biology, Faculty of Exact and Natural Sciences, University of Antioquia, Medellin, Colombia
| | - Gloria Patricia Cardona-Gómez
- Neuroscience Group of Antioquia, Cellular and Molecular Neurobiology Area, Faculty of Medicine, SIU, University of Antioquia, Calle 70, No. 52-21, Medellin, Colombia. .,Universidad de Antioquia, Sede de Investigación Universitaria (SIU), Calle 62 # 52 - 59; Torre 1, Piso 4, Laboratorio 412, Medellín, Colombia.
| |
Collapse
|
13
|
Hatano A, Matsumoto M, Nakayama KI. Phosphoproteomics analyses show subnetwork systems in T-cell receptor signaling. Genes Cells 2016; 21:1095-1112. [DOI: 10.1111/gtc.12406] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/02/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Atsushi Hatano
- Department of Molecular and Cellular Biology; Medical Institute of Bioregulation; Kyushu University; 3-1-1 Maidashi Higashi-ku Fukuoka 812-8582 Japan
| | - Masaki Matsumoto
- Department of Molecular and Cellular Biology; Medical Institute of Bioregulation; Kyushu University; 3-1-1 Maidashi Higashi-ku Fukuoka 812-8582 Japan
| | - Keiichi I. Nakayama
- Department of Molecular and Cellular Biology; Medical Institute of Bioregulation; Kyushu University; 3-1-1 Maidashi Higashi-ku Fukuoka 812-8582 Japan
| |
Collapse
|
14
|
Wrasidlo W, Crews LA, Tsigelny IF, Stocking E, Kouznetsova VL, Price D, Paulino A, Gonzales T, Overk CR, Patrick C, Rockenstein E, Masliah E. Neuroprotective effects of the anti-cancer drug sunitinib in models of HIV neurotoxicity suggests potential for the treatment of neurodegenerative disorders. Br J Pharmacol 2015; 171:5757-73. [PMID: 25117211 DOI: 10.1111/bph.12875] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/30/2014] [Accepted: 08/03/2014] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Anti-retrovirals have improved and extended the life expectancy of patients with HIV. However, as this population ages, the prevalence of cognitive changes is increasing. Aberrant activation of kinases, such as receptor tyrosine kinases (RTKs) and cyclin-dependent kinase 5 (CDK5), play a role in the mechanisms of HIV neurotoxicity. Inhibitors of CDK5, such as roscovitine, have neuroprotective effects; however, CNS penetration is low. Interestingly, tyrosine kinase inhibitors (TKIs) display some CDK inhibitory activity and ability to cross the blood-brain barrier. EXPERIMENTAL APPROACH We screened a small group of known TKIs for a candidate with additional CDK5 inhibitory activity and tested the efficacy of the candidate in in vitro and in vivo models of HIV-gp120 neurotoxicity. KEY RESULTS Among 12 different compounds, sunitinib inhibited CDK5 with an IC50 of 4.2 μM. In silico analysis revealed that, similarly to roscovitine, sunitinib fitted 6 of 10 features of the CDK5 pharmacophore. In a cell-based model, sunitinib reduced CDK5 phosphorylation (pCDK5), calpain-dependent p35/p25 conversion and protected neuronal cells from the toxic effects of gp120. In glial fibrillary acidic protein-gp120 transgenic (tg) mice, sunitinib reduced levels of pCDK5, p35/p25 and phosphorylated tau protein, along with amelioration of the neurodegenerative pathology. CONCLUSIONS AND IMPLICATIONS Compounds such as sunitinib with dual kinase inhibitory activity could ameliorate the cognitive impairment associated with chronic HIV infection of the CNS. Moreover, repositioning existing low MW compounds holds promise for the treatment of patients with neurodegenerative disorders.
Collapse
Affiliation(s)
- Wolf Wrasidlo
- Department of Neurosciences, University of California, San Diego, CA, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Masvekar RR, El-Hage N, Hauser KF, Knapp PE. GSK3β-activation is a point of convergence for HIV-1 and opiate-mediated interactive neurotoxicity. Mol Cell Neurosci 2015; 65:11-20. [PMID: 25616162 DOI: 10.1016/j.mcn.2015.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 12/22/2014] [Accepted: 01/19/2015] [Indexed: 01/03/2023] Open
Abstract
Infection of the CNS with HIV-1 occurs rapidly after primary peripheral infection. HIV-1 can induce a wide range of neurological deficits, collectively known as HIV-1-associated neurocognitive disorders. Our previous work has shown that the selected neurotoxic effects induced by individual viral proteins, Tat and gp120, and by HIV(+) supernatant are enhanced by co-exposure to morphine. This mimics co-morbid neurological effects observed in opiate-abusing HIV(+) patients. Although there is a correlation between opiate drug abuse and progression of HIV-1-associated neurocognitive disorders, the mechanisms underlying interactions between HIV-1 and opiates remain obscure. Previous studies have shown that HIV-1 induces neurotoxic effects through abnormal activation of GSK3β. Interestingly, expression of GSK3β has shown to be elevated in brains of young opiate abusers indicating that GSK3β is also linked to neuropathology seen with opiate-abusing patients. Thus, we hypothesize that GSK3β activation is a point of convergence for HIV- and opiate-mediated interactive neurotoxic effects. Neuronal cultures were treated with supernatant from HIV-1SF162-infected THP-1 cells, in the presence or absence of morphine and GSK3β inhibitors. Our results show that GSK3β inhibitors, including valproate and small molecule inhibitors, significantly reduce HIV-1-mediated neurotoxic outcomes, and also negate interactions with morphine that result in cell death, suggesting that GSK3β-activation is an important point of convergence and a potential therapeutic target for HIV- and opiate-mediated neurocognitive deficits.
Collapse
Affiliation(s)
- Ruturaj R Masvekar
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Nazira El-Hage
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Kurt F Hauser
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Pamela E Knapp
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA; Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298, USA.
| |
Collapse
|
16
|
Fields JA, Dumaop W, Crews L, Adame A, Spencer B, Metcalf J, He J, Rockenstein E, Masliah E. Mechanisms of HIV-1 Tat neurotoxicity via CDK5 translocation and hyper-activation: role in HIV-associated neurocognitive disorders. Curr HIV Res 2015; 13:43-54. [PMID: 25760044 PMCID: PMC4455959 DOI: 10.2174/1570162x13666150311164201] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 12/13/2014] [Accepted: 01/29/2015] [Indexed: 12/16/2022]
Abstract
The advent of more effective antiretroviral therapies has reduced the frequency of HIV dementia, however the prevalence of milder HIV associated neurocognitive disorders [HAND] is actually rising. Neurodegenerative mechanisms in HAND might include toxicity by secreted HIV-1 proteins such as Tat, gp120 and Nef that could activate neuro-inflammatory pathways, block autophagy, promote excitotoxicity, oxidative stress, mitochondrial dysfunction and dysregulation of signaling pathways. Recent studies have shown that Tat could interfere with several signal transduction mechanisms involved in cytoskeletal regulation, cell survival and cell cycle re-entry. Among them, Tat has been shown to hyper-activate cyclin-dependent kinase [CDK] 5, a member of the Ser/Thr CDKs involved in cell migration, angiogenesis, neurogenesis and synaptic plasticity. CDK5 is activated by binding to its regulatory subunit, p35 or p39. For this manuscript we review evidence showing that Tat, via calcium dysregulation, promotes calpain-1 cleavage of p35 to p25, which in turn hyper-activates CDK5 resulting in abnormal phosphorylation of downstream targets such as Tau, collapsin response mediator protein-2 [CRMP2], doublecortin [DCX] and MEF2. We also present new data showing that Tat interferes with the trafficking of CDK5 between the nucleus and cytoplasm. This results in prolonged presence of CDK5 in the cytoplasm leading to accumulation of aberrantly phosphorylated cytoplasmic targets [e.g.: Tau, CRMP2, DCX] that impair neuronal function and eventually lead to cell death. Novel therapeutic approaches with compounds that block Tat mediated hyper-activation of CDK5 might be of value in the management of HAND.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Eliezer Masliah
- Department of Neurosciences, School of Medicine, University of California San Diego, 9500 Gilman Dr., MTF 348, La Jolla, CA 92093-0624, USA.
| |
Collapse
|
17
|
Zyskind JW, Wang Y, Cho G, Ting JH, Kolson DL, Lynch DR, Jordan-Sciutto KL. E2F1 in neurons is cleaved by calpain in an NMDA receptor-dependent manner in a model of HIV-induced neurotoxicity. J Neurochem 2014; 132:742-55. [PMID: 25279448 DOI: 10.1111/jnc.12956] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 09/18/2014] [Indexed: 02/07/2023]
Abstract
The transcription factor E2F1 activates gene targets required for G1 -S phase progression and for apoptosis, and exhibits increased expression levels in neurons in several CNS diseases including HIV encephalitis, Alzheimer disease, and Parkinson's Disease. While E2F1 is known to regulate cell viability through activation of caspases, here we present evidence supporting the involvement of E2F1 in N-methyl-d-aspartate (NMDA) receptor-dependent, HIV-induced neuronal death mediated by calpains. Using an in vitro model of HIV-induced neurotoxicity that is dependent on NMDA receptor and calpain activation, we have shown that cortical neurons lacking functional E2F1 are less susceptible to neuronal death. In addition, we report that neuronal E2F1 is cleaved by calpain to a stable 55-kiloDalton fragment following NR2B-dependent NMDA receptor stimulation. This cleavage of E2F1 is protein conformation-dependent and involves at least two cleavage events, one at each terminus of the protein. Intriguingly, the stabilized E2F1 cleavage product is produced in post-mitotic neurons of all ages, but fails to be stabilized in cycling cells. Finally, we show that a matching E2F1 cleavage product is produced in human fetal neurons, suggesting that calpain cleavage of E2F1 may be produced in human cortical tissue. These results suggest neuronal E2F1 is processed in a novel manner in response to NMDA receptor-mediated toxicity, a mechanism implicated in HIV-associated neurocognitive disorders pathogenesis as well as several other diseases of the CNS. After crossing the blood-brain barrier, HIV-infected monocytes differentiate into macrophages and release excitotoxins and inflammatory factors including glutamate into the brain parenchyma (1). These factors stimulate neuronal N-Methyl-d-aspartate (NMDA) receptors (2), causing calcium influx (3) and subsequent activation of the cysteine protease calpain (4). Activated calpain cleaves multiple substrates including E2F1, producing a stabilized protein fragment with truncations at the N- and C-terminus (5). Calpain-cleaved E2F1 may contribute to calpain-mediated neuronal damage observed in NMDA receptor-mediated neurotoxicity (6).
Collapse
Affiliation(s)
- Jacob W Zyskind
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | | | | | | | | | | |
Collapse
|
18
|
Brown LAM, Scarola J, Smith AJ, Sanberg PR, Tan J, Giunta B. The role of tau protein in HIV-associated neurocognitive disorders. Mol Neurodegener 2014; 9:40. [PMID: 25304757 PMCID: PMC4210623 DOI: 10.1186/1750-1326-9-40] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 09/15/2014] [Indexed: 11/14/2022] Open
Abstract
Given the increased life expectancy of human immunodeficiency virus (HIV) infected individuals treated with combination antiretroviral therapy (cART) and the ongoing inflammation observed in the brains of these patients, it is likely that premature neurodegeneration as measured by phospho-tau (p-tau) or increased total tau (t-tau) protein may become an increasing problem. This review examines the seven human studies that have occurred over the past 14 years measuring p-tau and/or t-tau in cerebrospinal fluid (CSF) or via post-mortem brain immunohistochemistry. Although not all studies are in agreement as to the changes in p-and t-tau in HIV infected patients, HIV persists in the brain despite cART. Thus is it is suggested that those maintained on long-term cART may develop tau pathology beyond the extent seen in the studies reviewed herein and overtime may then reach the threshold for clinical manifestation.
Collapse
Affiliation(s)
| | | | | | | | | | - Brian Giunta
- Department of Molecular Pharmacology and Physiology, University of South Florida, Morsani College of Medicine, Tampa, FL 33613, USA.
| |
Collapse
|
19
|
Akay C, Cooper M, Odeleye A, Jensen BK, White MG, Vassoler F, Gannon PJ, Mankowski J, Dorsey JL, Buch AM, Cross SA, Cook DR, Peña MM, Andersen ES, Christofidou-Solomidou M, Lindl KA, Zink MC, Clements J, Pierce RC, Kolson DL, Jordan-Sciutto KL. Antiretroviral drugs induce oxidative stress and neuronal damage in the central nervous system. J Neurovirol 2014; 20:39-53. [PMID: 24420448 PMCID: PMC3928514 DOI: 10.1007/s13365-013-0227-1] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 12/10/2013] [Accepted: 12/13/2013] [Indexed: 01/09/2023]
Abstract
HIV-associated neurocognitive disorder (HAND), characterized by a wide spectrum of behavioral, cognitive, and motor dysfunctions, continues to affect approximately 50 % of HIV(+) patients despite the success of combination antiretroviral drug therapy (cART) in the periphery. Of note, potential toxicity of antiretroviral drugs in the central nervous system (CNS) remains remarkably underexplored and may contribute to the persistence of HAND in the cART era. Previous studies have shown antiretrovirals (ARVs) to be neurotoxic in the peripheral nervous system in vivo and in peripheral neurons in vitro. Alterations in lipid and protein metabolism, mitochondrial damage, and oxidative stress all play a role in peripheral ARV neurotoxicity. We hypothesized that ARVs also induce cellular stresses in the CNS, ultimately leading to neuronal damage and contributing to the changing clinical and pathological picture seen in HIV-positive patients in the cART era. In this report, we show that ARVs are neurotoxic in the CNS in both pigtail macaques and rats in vivo. Furthermore, in vitro, ARVs lead to accumulation of reactive oxygen species (ROS), and ultimately induction of neuronal damage and death. Whereas ARVs alone caused some activation of the endogenous antioxidant response in vitro, augmentation of this response by a fumaric acid ester, monomethyl fumarate (MMF), blocked ARV-induced ROS generation, and neuronal damage/death. These findings implicate oxidative stress as a contributor to the underlying mechanisms of ARV-induced neurotoxicity and will provide an access point for adjunctive therapies to complement ARV therapy and reduce neurotoxicity in this patient population.
Collapse
Affiliation(s)
- Cagla Akay
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Michael Cooper
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Akinleye Odeleye
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Brigid K. Jensen
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Michael G. White
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Fair Vassoler
- Department of Psychiatry, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Patrick J. Gannon
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Joseph Mankowski
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Jamie L. Dorsey
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Alison M. Buch
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Stephanie A. Cross
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Denise R. Cook
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Michelle-Marie Peña
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - Emily S. Andersen
- Department of Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | | | - Kathryn A. Lindl
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| | - M. Christine Zink
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Janice Clements
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - R. Christopher Pierce
- Department of Psychiatry, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Dennis L. Kolson
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
| | - Kelly L. Jordan-Sciutto
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy Bldg, Philadelphia, PA 19104-6030 USA
| |
Collapse
|
20
|
Darbinian N, Khalili K, Amini S. Neuroprotective activity of pDING in response to HIV-1 Tat. J Cell Physiol 2013; 229:153-61. [PMID: 23955241 DOI: 10.1002/jcp.24392] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 04/17/2013] [Indexed: 12/13/2022]
Abstract
Although neurons are not productively infected with HIV-1, neuronal injury and death are frequently seen in the brains of AIDS patients with neurological and neurocognitive disorders. Evidently, viral proteins including Tat and cellular inflammatory factors released by activated and/or infected microglia, macrophages, and astrocytes contribute to neuronal cell death. Several studies have demonstrated that HIV-1 associated neuronal cell injury is mediated by dysregulation of signaling pathways that are controlled, in part, by a class of serine/threonine kinases. In this study, we demonstrate that pDING, a novel plant-derived phosphate binding protein has the capacity to reduce the severity of injury and death caused by HIV-1 and its neurotoxic Tat protein. We demonstrate that pDING, also called p27SJ/p38SJ, protects cells from the loss of neuronal processes induced by Tat and promotes neuronal outgrowth after Tat-mediated injury. Further, expression of pDING prevents Tat-induced oxidative stress and mitochondrial permeability. With its profound phosphatase activity, pDING controls the activity of several kinases including MAPK, Cdk5, and their downstream target protein, MEF2, which is implicated in neuronal cell protection. Our results show that expression of pDING in neuronal cells diminishes the level of hyperphosphorylated forms of Cdk5 and MEF2 caused by Tat and the other neurotoxic agents that are secreted by the HIV-1 infected cells. These observations suggest that pDING, through its phosphatase activity, has the ability to manipulate the state of phosphorylation and activity of several factors involved in neuronal cell health in response to HIV-1.
Collapse
Affiliation(s)
- Nune Darbinian
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, Pennsylvania
| | | | | |
Collapse
|
21
|
Colacurcio DJ, Yeager A, Kolson DL, Jordan-Sciutto KL, Akay C. Calpain-mediated degradation of MDMx/MDM4 contributes to HIV-induced neuronal damage. Mol Cell Neurosci 2013; 57:54-62. [PMID: 24128662 PMCID: PMC3868345 DOI: 10.1016/j.mcn.2013.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 09/10/2013] [Accepted: 10/05/2013] [Indexed: 10/26/2022] Open
Abstract
Neuronal damage in HIV-associated Neurocognitive Disorders (HAND) has been linked to inflammation induced by soluble factors released by HIV-infected, and non-infected, activated macrophages/microglia (HIV M/M) in the brain. It has been suggested that aberrant neuronal cell cycle activation determines cell fate in response to these toxic factors. We have previously shown increased expression of cell cycle proteins such as E2F1 and phosphorylated pRb in HAND midfrontal cortex in vivo and in primary neurons exposed to HIV M/M supernatants in vitro. In addition, we have previously shown that MDMx (also referred to as MDM4), a negative regulator of E2F1, was decreased in the brain in a primate model of HIV-induced CNS neurodegeneration. Thus, we hypothesized that MDMx provides indirect neuroprotection from HIV-induced neurodegeneration in our in vitro model. In this report, we found significant reductions in MDMx protein levels in the mid-frontal cortex of patients with HAND. In addition, treatment of primary rat neuroglial cultures with HIV M/M led to NMDA receptor- and calpain-dependent degradation of MDMx and decreased neuronal survival, while overexpression of MDMx conferred partial protection from HIV M/M toxicity in vitro. Further, our results demonstrate that MDMx is a novel and direct calpain substrate. Finally, blocking MDMx activity led to neuronal death in vitro in the absence of toxic stimulus, which was reversed by calpain inhibition. Overall, our results indicate that MDMx plays a pro-survival role in neurons, and that strategies to stabilize and/or induce MDMx can provide neuroprotection in HAND and in other neurodegenerative diseases where calpain activation contributes to neuropathogenesis.
Collapse
Affiliation(s)
- Daniel J. Colacurcio
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 312 Levy Building, 240 South 40 Street, Philadelphia, PA, 19104
| | - Alyssa Yeager
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, 280C Clinical Research Building, 415 Curie Boulevard, Philadelphia, PA 19104
| | - Dennis L. Kolson
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, 280C Clinical Research Building, 415 Curie Boulevard, Philadelphia, PA 19104
| | - Kelly L. Jordan-Sciutto
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 312 Levy Building, 240 South 40 Street, Philadelphia, PA, 19104
| | - Cagla Akay
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, 312 Levy Building, 240 South 40 Street, Philadelphia, PA, 19104
| |
Collapse
|
22
|
Mattson MP. Exercise and the brain: a slap on the HAND. J Neurovirol 2013; 19:407-9. [PMID: 24072548 PMCID: PMC3851339 DOI: 10.1007/s13365-013-0208-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 09/16/2013] [Indexed: 12/11/2022]
Affiliation(s)
- Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, 21224, USA,
| |
Collapse
|
23
|
Lee MH, Amin ND, Venkatesan A, Wang T, Tyagi R, Pant HC, Nath A. Impaired neurogenesis and neurite outgrowth in an HIV-gp120 transgenic model is reversed by exercise via BDNF production and Cdk5 regulation. J Neurovirol 2013; 19:418-31. [PMID: 23982957 PMCID: PMC3799978 DOI: 10.1007/s13365-013-0194-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 07/31/2013] [Indexed: 01/26/2023]
Abstract
Human immunodeficiency virus (HIV) infection-associated neurocognitive disorders is accompanied with brain atrophy. In these patients, impairment of adult neurogenesis and neurite outgrowth in the hippocampus may contribute to cognitive dysfunction. Although running exercises can enhance neurogenesis and normalize neurite outgrowth, the underlying molecular mechanisms are not well understood. The HIV envelope protein, gp120, has been shown to impair neurogenesis. Using a gp120 transgenic mouse model, we demonstrate that exercise stimulated neural progenitor cell (NPC) proliferation in the hippocampal dentate gyrus and increased the survival rate and generation of newborn cells. However, sustained exercise activity was necessary as the effects were reversed by detraining. Exercise also normalized dendritic outgrowth of neurons. Furthermore, it increased the expression of hippocampal brain-derived neurotrophic factor (BDNF) and normalized hyperactivation of cyclin-dependent kinase 5 (Cdk5). Hyperactivated Cdk5 or gp120 treatment led to aberrant neurite outgrowth and BDNF treatment normalized the neurite outgrowth in NPC cultures. These results suggest that sustained exercise has trophic activity on the neuronal lineage which is mediated by Cdk5 modulation of the BDNF pathway.
Collapse
Affiliation(s)
- Myoung-Hwa Lee
- Section of Infections of the Nervous System, National Institutes of Health, M.D. Bldg 10, Room 7C-103, 10 Center Drive, Bethesda, MD, 20892, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Abstract
Low-frequency depression (LFD) of transmitter release occurs at phasic synapses with stimulation at 0.2 Hz in both isolated crayfish (Procambarus clarkii) neuromuscular junction (NMJ) preparations and in intact animals. LFD is regulated by presynaptic activity of the Ca(2+)-dependent phosphatase calcineurin (Silverman-Gavrila and Charlton, 2009). Since the fast Ca(2+) chelator BAPTA-AM inhibits LFD but the slow chelator EGTA-AM does not, the Ca(2+) sensor for LFD may be close to a Ca(2+) source at active zones. Calcineurin can be activated by the Ca(2+)-activated protease calpain, and immunostaining showed that both proteins are present at nerve terminals. Three calpain inhibitors, calpain inhibitor I, MDL-28170, and PD150606, but not the control compound PD145305, inhibit LFD both in the intact animal as shown by electromyograms and by intracellular recordings at neuromuscular junctions. Analysis of mini-EPSPs indicated that these inhibitors had minimal postsynaptic effects. Proteolytic activity in CNS extract, detected by a fluorescent calpain substrate, was modulated by Ca(2+) and calpain inhibitors. Western blot analysis of CNS extract showed that proteolysis of calcineurin to a fragment consistent with the constitutively active form required Ca(2+) and was blocked by calpain inhibitors. Inhibition of LFD by calpain inhibition blocks the reduction in phosphoactin and the depolymerization of tubulin that normally occurs in LFD, probably by blocking the dephosphorylation of cytoskeletal proteins by calcineurin. In contrast, high-frequency depression does not involve protein phosphorylation- or calpain-dependent mechanisms. LFD may involve a specific pathway in which local Ca(2+) signaling activates presynaptic calpain and calcineurin at active zones and causes changes of tubulin cytoskeleton.
Collapse
|
25
|
Ramadan E, Basselin M, Chang L, Chen M, Ma K, Rapoport SI. Chronic lithium feeding reduces upregulated brain arachidonic acid metabolism in HIV-1 transgenic rat. J Neuroimmune Pharmacol 2012; 7:701-13. [PMID: 22760927 PMCID: PMC3478068 DOI: 10.1007/s11481-012-9381-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 06/04/2012] [Indexed: 01/09/2023]
Abstract
HIV-1 transgenic (Tg) rats, a model for human HIV-1 associated neurocognitive disorder (HAND), show upregulated markers of brain arachidonic acid (AA) metabolism with neuroinflammation after 7 months of age. Since lithium decreases AA metabolism in a rat lipopolysaccharide model of neuroinflammation, and may be useful in HAND, we hypothesized that lithium would dampen upregulated brain AA metabolism in HIV-1 Tg rats. Regional brain AA incorporation coefficients k* and rates J ( in ), markers of AA signaling and metabolism, were measured in 81 brain regions using quantitative autoradiography, after intravenous [1-(14) C]AA infusion in unanesthetized 10-month-old HIV-1 Tg and age-matched wildtype rats that had been fed a control or LiCl diet for 6 weeks. k* and J ( in ) for AA were significantly higher in HIV-1 Tg than wildtype rats fed the control diet. Lithium feeding reduced plasma unesterified AA concentration in both groups and J ( in ) in wildtype rats, and blocked increments in k* (19 of 54 regions) and J ( in ) (77 of 81 regions) in HIV-1 Tg rats. These in vivo neuroimaging data indicate that lithium treatment dampened upregulated brain AA metabolism in HIV-1 Tg rats. Lithium may improve cognitive dysfunction and be neuroprotective in HIV-1 patients with HAND through a comparable effect.
Collapse
Affiliation(s)
- Epolia Ramadan
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA
| | - Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA
| | - Lisa Chang
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA
| | - Mei Chen
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA
| | - Kaizong Ma
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA
| | - Stanley I. Rapoport
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
26
|
Cheng B, Chen J, Bai B, Xin Q. Neuroprotection of apelin and its signaling pathway. Peptides 2012; 37:171-3. [PMID: 22820556 DOI: 10.1016/j.peptides.2012.07.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 07/15/2012] [Accepted: 07/15/2012] [Indexed: 12/15/2022]
Abstract
Apelin was initially isolated from bovine stomach and is an endogenous neuropeptide. It is a native ligand of the apelin receptor (APJ). Some research has found that apelin peptides alter blood pressure, feeding behavior, and pituitary hormone release. However, a new neuroprotective effect of apelin peptides was only recently discovered. This review summarizes the evidence of apelin-neuroprotection, which has the potential to cure acute and chronic neurological diseases.
Collapse
Affiliation(s)
- Baohua Cheng
- Department of Neurology, Jining Medical University, Jining City, Shandong Province, PR China.
| | | | | | | |
Collapse
|
27
|
Involvement of calpain/p35-p25/Cdk5/NMDAR signaling pathway in glutamate-induced neurotoxicity in cultured rat retinal neurons. PLoS One 2012; 7:e42318. [PMID: 22870316 PMCID: PMC3411656 DOI: 10.1371/journal.pone.0042318] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 07/03/2012] [Indexed: 11/19/2022] Open
Abstract
We investigated possible involvement of a calpain/p35-p25/cyclin-dependent kinase 5 (Cdk5) signaling pathway in modifying NMDA receptors (NMDARs) in glutamate-induced injury of cultured rat retinal neurons. Glutamate treatment decreased cell viability and induced cell apoptosis, which was accompanied by an increase in Cdk5 and p-Cdk5T15 protein levels. The Cdk5 inhibitor roscovitine rescued the cell viability and inhibited the cell apoptosis. In addition, the protein levels of both calpain 2 and calpain-specific alpha-spectrin breakdown products (SBDPs), which are both Ca2+-dependent, were elevated in glutamate-induced cell injury. The protein levels of Cdk5, p-Cdk5T15, calpain 2 and SBDPs tended to decline with glutamate treatments of more than 9 h. Furthermore, the elevation of SBDPs was attenuated by either D-APV, a NMDAR antagonist, or CNQX, a non-NMDAR antagonist, but was hardly changed by the inhibitors of intracellular calcium stores dantrolene and xestospongin. Moreover, the Cdk5 co-activator p35 was significantly up-regulated, whereas its cleaved product p25 expression showed a transient increase. Glutamate treatment for less than 9 h also considerably enhanced the ratio of the Cdk5-phosphorylated NMDAR subunit NR2A at Ser1232 site (p-NR2AS1232) and NR2A (p-NR2AS1232/NR2A), and caused a translocation of p-NR2AS1232 from the cytosol to the plasma membrane. The enhanced p-NR2AS1232 was inhibited by roscovitine, but augmented by over-expression of Cdk5. Calcium imaging experiments further showed that intracellular Ca2+ concentrations ([Ca2+]i) of retinal cells were steadily increased following glutamate treatments of 2 h, 6 h and 9 h. All these results suggest that the activation of the calpain/p35-p25/Cdk5 signaling pathway may contribute to glutamate neurotoxicity in the retina by up-regulating p-NR2AS1232 expression.
Collapse
|
28
|
Akay C, Lindl KA, Shyam N, Nabet B, Goenaga-Vazquez Y, Ruzbarsky J, Wang Y, Kolson DL, Jordan-Sciutto KL. Activation status of integrated stress response pathways in neurones and astrocytes of HIV-associated neurocognitive disorders (HAND) cortex. Neuropathol Appl Neurobiol 2012; 38:175-200. [PMID: 21883374 PMCID: PMC3708539 DOI: 10.1111/j.1365-2990.2011.01215.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
C. Akay, K. A. Lindl, N. Shyam, B. Nabet, Y. Goenaga‐Vazquez, J. Ruzbarsky, Y. Wang, D. L. Kolson and K. L. Jordan‐Sciutto (2012) Neuropathology and Applied Neurobiology38, 175–200 Activation status of integrated stress response pathways in neurones and astrocytes of HIV‐associated neurocognitive disorders (HAND) cortex Aims: Combined anti‐retroviral therapy (cART) has led to a reduction in the incidence of HIV‐associated dementia (HAD), a severe motor/cognitive disorder afflicting HIV(+) patients. However, the prevalence of subtler forms of neurocognitive dysfunction, which together with HAD are termed HIV‐associated neurocognitive disorders (HAND), continues to escalate in the post‐cART era. The microgliosis, astrogliosis, dendritic damage, and synaptic and neuronal loss observed in autopsy cases suggest an underlying neuroinflammatory process, due to the neurotoxic factors released by HIV‐infected/activated macrophages/microglia in the brain, might underlie the pathogenesis of HAND in the post‐cART era. These factors are known to induce the integrated stress response (ISR) in several neurodegenerative diseases; we have previously shown that BiP, an indicator of general ISR activation, is upregulated in cortical autopsy tissue from HIV‐infected patients. The ISR is composed of three pathways, each with its own initiator protein: PERK, IRE1α and ATF6. Methods: To further elucidate the specific ISR pathways activated in the central nervous system of HAND patients, we examined the protein levels of several ISR proteins, including ATF6, peIF2α and ATF4, in cortical tissue from HIV‐infected patients. Results: The ISR does not respond in an all‐or‐none fashion in HAND, but rather demonstrates a nuanced activation pattern. Specifically, our studies implicate the ATF6 pathway of the ISR as a more likely candidate than the PERK pathway for increases in BiP levels in astrocytes. Conclusion: These findings begin to characterize the nature of the ISR response in HAND and provide potential targets for therapeutic intervention in this disease.
Collapse
Affiliation(s)
- C Akay
- Department of Pathology, School of Dental Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6030, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Cross SA, Cook DR, Chi AWS, Vance PJ, Kolson LL, Wong BJ, Jordan-Sciutto KL, Kolson DL. Dimethyl fumarate, an immune modulator and inducer of the antioxidant response, suppresses HIV replication and macrophage-mediated neurotoxicity: a novel candidate for HIV neuroprotection. THE JOURNAL OF IMMUNOLOGY 2011; 187:5015-25. [PMID: 21976775 DOI: 10.4049/jimmunol.1101868] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite antiretroviral therapy (ART), HIV infection promotes cognitive dysfunction and neurodegeneration through persistent inflammation and neurotoxin release from infected and/or activated macrophages/microglia. Furthermore, inflammation and immune activation within both the CNS and periphery correlate with disease progression and morbidity in ART-treated individuals. Accordingly, drugs targeting these pathological processes in the CNS and systemic compartments are needed for effective, adjunctive therapy. Using our in vitro model of HIV-mediated neurotoxicity, in which HIV-infected monocyte-derived macrophages release excitatory neurotoxins, we show that HIV infection dysregulates the macrophage antioxidant response and reduces levels of heme oxygenase-1 (HO-1). Furthermore, restoration of HO-1 expression in HIV-infected monocyte-derived macrophages reduces neurotoxin release without altering HIV replication. Given these novel observations, we have identified dimethyl fumarate (DMF), used to treat psoriasis and showing promising results in clinical trials for multiple sclerosis, as a potential neuroprotectant and HIV disease-modifying agent. DMF, an immune modulator and inducer of the antioxidant response, suppresses HIV replication and neurotoxin release. Two distinct mechanisms are proposed: inhibition of NF-κB nuclear translocation and signaling, which could contribute to the suppression of HIV replication, and induction of HO-1, which is associated with decreased neurotoxin release. Finally, we found that DMF attenuates CCL2-induced monocyte chemotaxis, suggesting that DMF could decrease recruitment of activated monocytes to the CNS in response to inflammatory mediators. We propose that dysregulation of the antioxidant response during HIV infection drives macrophage-mediated neurotoxicity and that DMF could serve as an adjunctive neuroprotectant and HIV disease modifier in ART-treated individuals.
Collapse
Affiliation(s)
- Stephanie A Cross
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Crews L, Ruf R, Patrick C, Dumaop W, Trejo-Morales M, Achim CL, Rockenstein E, Masliah E. Phosphorylation of collapsin response mediator protein-2 disrupts neuronal maturation in a model of adult neurogenesis: Implications for neurodegenerative disorders. Mol Neurodegener 2011; 6:67. [PMID: 21943307 PMCID: PMC3204248 DOI: 10.1186/1750-1326-6-67] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 09/24/2011] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Recent studies suggest that the pathogenic process in neurodegenerative disorders may disrupt mature neuronal circuitries and neurogenesis in the adult brain. Abnormal activation of CDK5 is associated with neurodegenerative disorders, and recently a critical role for CDK5 in adult neurogenesis has been identified. We have developed an in vitro model of abnormal CDK5 activation during adult hippocampal neurogenesis, and here we used this model to investigate aberrantly phosphorylated downstream targets of CDK5. RESULTS Abnormal CDK5 activation in an in vitro model of adult neurogenesis results in hyperphosphorylation of collapsin-response mediator protein-2 (CRMP2) and impaired neurite outgrowth. Inhibition of CDK5, or expression of a non-phosphorylatable (S522A) CRMP2 construct reduced CRMP2 hyperphosphorylation, and reversed neurite outgrowth deficits. CRMP2 plays a role in microtubule dynamics; therefore we examined the integrity of microtubules in this model using biochemical and electron microscopy techniques. We found that microtubule organization was disrupted under conditions of CDK5 activation. Finally, to study the relevance of these findings to neurogenesis in neurodegenerative conditions associated with HIV infection, we performed immunochemical analyses of the brains of patients with HIV and transgenic mice expressing HIV-gp120 protein. CDK5-mediated CRMP2 phosphorylation was significantly increased in the hippocampus of patients with HIV encephalitis and in gp120 transgenic mice, and this effect was rescued by genetic down-modulation of CDK5 in the mouse model. CONCLUSIONS These results reveal a functional mechanism involving microtubule destabilization through which abnormal CDK5 activation and CRMP2 hyperphosphorylation might contribute to defective neurogenesis in neurodegenerative disorders such as HIV encephalitis.
Collapse
Affiliation(s)
- Leslie Crews
- Department of Neurosciences; University of California, San Diego; 9500 Gilman Drive, La Jolla, CA 92093-0624, USA.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Cook DR, Gleichman AJ, Cross SA, Doshi S, Ho W, Jordan-Sciutto KL, Lynch DR, Kolson DL. NMDA receptor modulation by the neuropeptide apelin: implications for excitotoxic injury. J Neurochem 2011; 118:1113-23. [PMID: 21749375 DOI: 10.1111/j.1471-4159.2011.07383.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Excitotoxic neuronal damage via over-activation of the NMDA receptor has been implicated in many neurodegenerative diseases. In vitro modeling of excitotoxic injury has shown that activation of G-protein coupled receptors (GPCRs) counteracts such injury through modulation of neuronal pro-survival pathways and/or NMDA receptor signaling. We have previously demonstrated that the GPCR APJ and its endogenous neuropeptide ligand apelin can protect neurons against excitotoxicity, but the mechanism(s) of this neuroprotection remain incompletely understood. We hypothesized that apelin can promote neuronal survival by activating pro-survival signaling as well as inhibiting NMDA receptor-mediated excitotoxic signaling cascades. Our results demonstrate that (i) apelin activates pro-survival signaling via inositol trisphosphate (IP(3) ), protein kinase C (PKC), mitogen-activated protein kinase kinase 1/2 (MEK1/2), and extracellular signal-regulated kinase-1/2 (ERK1/2) to protect against excitotoxicity, and (ii) apelin inhibits excitotoxic signaling by attenuating NMDA receptor and calpain activity, and by modulating NMDA receptor subunit NR2B phosphorylation at serine 1480. These studies delineate a novel apelinergic signaling pathway that concurrently promotes survival and limits NMDA receptor-mediated injury to protect neurons against excitotoxicity. Defining apelin-mediated neuroprotection advances our understanding of neuroprotective pathways and will potentially improve our ability to develop therapeutics for excitotoxicity-associated neurodegenerative disorders.
Collapse
Affiliation(s)
- Denise R Cook
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Akay C, Lindl KA, Wang Y, White MG, Isaacman-Beck J, Kolson DL, Jordan-Sciutto KL. Site-specific hyperphosphorylation of pRb in HIV-induced neurotoxicity. Mol Cell Neurosci 2011; 47:154-65. [PMID: 21504794 DOI: 10.1016/j.mcn.2011.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/25/2011] [Accepted: 04/04/2011] [Indexed: 12/18/2022] Open
Abstract
HIV-Associated Neurocognitive Disorder (HAND) remains a serious complication of HIV infection, despite combined Anti-Retroviral Therapy (cART). Neuronal dysfunction and death are attributed to soluble factors released from activated and/or HIV-infected macrophages. Most of these factors affect the cell cycle machinery, determining cellular outcomes even in the absence of cell division. One of the earliest events in cell cycle activation is hyperphosphorylation of the retinoblastoma protein, pRb (ppRb). We and others have previously shown increased ppRb expression in the CNS of patients with HIV encephalitis (HIVE) and in neurons in an in vitro model of HIV-induced neurodegeneration. However, trophic factors also lead to an increase in neuronal ppRb with an absence of cell death, suggesting that, depending on the stimulus, hyperphosphorylation of pRb can have different outcomes on neuronal fate. pRb has multiple serines and threonines targeted for phosphorylation by distinct kinases, and we hypothesized that different stimuli may target separate sites for phosphorylation. Thus, to determine whether pRb is differentially phosphorylated in response to different stimuli and whether any of these sites is preferentially phosphorylated in association with HIV-induced neurotoxicity, we treated primary rat mixed cortical cultures with trophic factors, BDNF or RANTES, or with the neurotoxic factor, N-methyl-d-aspartate (NMDA), or with supernatants containing factors secreted by HIV-infected monocyte-derived macrophages (HIV-MDM), our in vitro model of HIV-induced neurodegeneration. We found that, while BDNF and RANTES phosphorylated serine807/811 and serine608 in vitro, treatment with HIV-MDM did not, even though these trophic factors are components of HIV-MDM. Rather, HIV-MDM targets a specific phosphorylation site, serine795, of pRb for phosphorylation in vitro and this ppRb isoform is also increased in HIV-infected brains in vivo. Further, overexpression of a nonphosphorylatable pRb (ppRb S795A) attenuated HIV-MDM-induced neurotoxicity. These findings indicate that HIV-infection in the brain is associated with site-specific hyperphosphorylation of pRb at serine795, which is not induced by other tested stimuli, and that this phosphorylation contributes to neuronal death in this disease, demonstrating that specific pRb sites are differentially targeted and may have diverse impacts on the viability of post-mitotic neurons.
Collapse
Affiliation(s)
- C Akay
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | |
Collapse
|
33
|
Patrick C, Crews L, Desplats P, Dumaop W, Rockenstein E, Achim CL, Everall IP, Masliah E. Increased CDK5 expression in HIV encephalitis contributes to neurodegeneration via tau phosphorylation and is reversed with Roscovitine. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1646-61. [PMID: 21435449 PMCID: PMC3078446 DOI: 10.1016/j.ajpath.2010.12.033] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 11/10/2010] [Accepted: 12/16/2010] [Indexed: 12/20/2022]
Abstract
Recent treatments with highly active antiretroviral therapy (HAART) regimens have been shown to improve general clinical status in patients with human immunodeficiency virus (HIV) infection; however, the prevalence of cognitive alterations and neurodegeneration has remained the same or has increased. These deficits are more pronounced in the subset of HIV patients with the inflammatory condition known as HIV encephalitis (HIVE). Activation of signaling pathways such as GSK3β and CDK5 has been implicated in the mechanisms of HIV neurotoxicity; however, the downstream mediators of these effects are unclear. The present study investigated the involvement of CDK5 and tau phosphorylation in the mechanisms of neurodegeneration in HIVE. In the frontal cortex of patients with HIVE, increased levels of CDK5 and p35 expression were associated with abnormal tau phosphorylation. Similarly, transgenic mice engineered to express the HIV protein gp120 exhibited increased brain levels of CDK5 and p35, alterations in tau phosphorylation, and dendritic degeneration. In contrast, genetic knockdown of CDK5 or treatment with the CDK5 inhibitor roscovitine improved behavioral performance in the water maze test and reduced neurodegeneration, abnormal tau phosphorylation, and astrogliosis in gp120 transgenic mice. These findings indicate that abnormal CDK5 activation contributes to the neurodegenerative process in HIVE via abnormal tau phosphorylation; thus, reducing CDK5 might ameliorate the cognitive impairments associated with HIVE.
Collapse
Affiliation(s)
- Christina Patrick
- Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Leslie Crews
- Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Paula Desplats
- Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Wilmar Dumaop
- Department of Pathology, University of California, San Diego, La Jolla, California
| | - Edward Rockenstein
- Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Cristian L. Achim
- Department of Psychiatry, University of California, San Diego, La Jolla, California
| | - Ian P. Everall
- Department of Psychiatry, University of California, San Diego, La Jolla, California
- Department of Psychiatry, University of Melbourne, Victoria, Australia
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, California
- Department of Pathology, University of California, San Diego, La Jolla, California
| |
Collapse
|
34
|
Li J, Ye L, Cook DR, Wang X, Liu J, Kolson DL, Persidsky Y, Ho WZ. Soybean-derived Bowman-Birk inhibitor inhibits neurotoxicity of LPS-activated macrophages. J Neuroinflammation 2011; 8:15. [PMID: 21324129 PMCID: PMC3046894 DOI: 10.1186/1742-2094-8-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Accepted: 02/15/2011] [Indexed: 12/12/2022] Open
Abstract
Background Lipopolysaccharide (LPS), the major component of the outer membrane of gram-negative bacteria, can activate immune cells including macrophages. Activation of macrophages in the central nervous system (CNS) contributes to neuronal injury. Bowman-Birk inhibitor (BBI), a soybean-derived protease inhibitor, has anti-inflammatory properties. In this study, we examined whether BBI has the ability to inhibit LPS-mediated macrophage activation, reducing the release of pro-inflammatory cytokines and subsequent neurotoxicity in primary cortical neural cultures. Methods Mixed cortical neural cultures from rat were used as target cells for testing neurotoxicity induced by LPS-treated macrophage supernatant. Neuronal survival was measured using a cell-based ELISA method for expression of the neuronal marker MAP-2. Intracellular reactive oxygen species (ROS) production in macrophages was measured via 2', 7'-dichlorofluorescin diacetate (DCFH2DA) oxidation. Cytokine expression was determined by quantitative real-time PCR. Results LPS treatment of macrophages induced expression of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) and of ROS. In contrast, BBI pretreatment (1-100 μg/ml) of macrophages significantly inhibited LPS-mediated induction of these cytokines and ROS. Further, supernatant from BBI-pretreated and LPS-activated macrophage cultures was found to be less cytotoxic to neurons than that from non-BBI-pretreated and LPS-activated macrophage cultures. BBI, when directly added to the neuronal cultures (1-100 μg/ml), had no protective effect on neurons with or without LPS-activated macrophage supernatant treatment. In addition, BBI (100 μg/ml) had no effect on N-methyl-D-aspartic acid (NMDA)-mediated neurotoxicity. Conclusions These findings demonstrate that BBI, through its anti-inflammatory properties, protects neurons from neurotoxicity mediated by activated macrophages.
Collapse
Affiliation(s)
- Jieliang Li
- Department of Pathology & Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
| | | | | | | | | | | | | | | |
Collapse
|
35
|
White MG, Wang Y, Akay C, Lindl KA, Kolson DL, Jordan-Sciutto KL. Parallel high throughput neuronal toxicity assays demonstrate uncoupling between loss of mitochondrial membrane potential and neuronal damage in a model of HIV-induced neurodegeneration. Neurosci Res 2011; 70:220-9. [PMID: 21291924 DOI: 10.1016/j.neures.2011.01.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 12/08/2010] [Accepted: 01/25/2011] [Indexed: 11/24/2022]
Abstract
Neurocognitive deficits seen in HIV-associated neurocognitive disorders (HANDs) are attributed to the release of soluble factors from CNS-resident, HIV-infected and/or activated macrophages and microglia. To study HIV-associated neurotoxicity, we used our in vitro model in which primary rat neuronal/glial cultures are treated with supernatants from cultured human monocyte-derived macrophages, infected with a CNS-isolated HIV-1 strain (HIV-MDM). We found that neuronal damage, detected as a loss of microtubule-associated protein-2 (MAP2), begins as early as 2h and is preceded by a loss of mitochondrial membrane potential (Δψ(m)). Interestingly, inhibitors of calpains, but not inhibitors of caspases, blocked MAP2 loss, however neither type of inhibitor prevented the loss of Δψ(m). To facilitate throughput for these studies, we refined a MAP2 cell-based-ELISA whose data closely compare with our standardized method of hand counting neurons. In addition, we developed a tetramethyl rhodamine methyl ester (TMRM)-based multi-well fluorescent plate assay for the evaluation of whole culture Δψ(m). Together, these findings indicate that calpain activation and loss of Δψ(m) may be parallel pathways to death in HIV-MDM-treated neurons and also demonstrate the validity of plate assays for assessing multiple experimental parameters as is useful for screening neurotherapeutics for neuronal damage and death.
Collapse
Affiliation(s)
- Michael G White
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | | | |
Collapse
|
36
|
Hisanaga SI, Endo R. Regulation and role of cyclin-dependent kinase activity in neuronal survival and death. J Neurochem 2010; 115:1309-21. [PMID: 21044075 DOI: 10.1111/j.1471-4159.2010.07050.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cyclin-dependent kinase (Cdk)5 is a proline-directed Ser/Thr protein kinase that functions mainly in neurons and is activated by binding to a regulatory subunit, p35 or p39. Kinase activity is mainly determined by the amount of p35 available, which is controlled by a balance between synthesis and degradation. Kinase activity is also regulated by Cdk5 phosphorylation, but the activity of phosphorylated Cdk5 is in contrast to that of cycling Cdks. Cdk5 is a versatile protein kinase that regulates multiple neuronal activities including neuronal migration and synaptic signaling. Further, Cdk5 plays a role in both survival and death of neurons. Long-term inactivation of Cdk5 triggers cell death, and the survival activity of Cdk5 is apparent when neurons suffer from stress. In contrast, hyper-activation of Cdk5 by p25 promotes cell death, probably by reactivating cell-cycle machinery in the nucleus. The pro-death activity is suppressed by membrane association of Cdk5 via myristoylation of p35. Appropriate activity, localization, and regulation of Cdk5 may be critical for long-term survival of neurons, which is more than 80 years in the case of humans.
Collapse
Affiliation(s)
- Shin-ichi Hisanaga
- Molecular Neuroscience, Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, Japan.
| | | |
Collapse
|
37
|
Soldan SS, Hollidge BS, Wagner V, Weber F, González-Scarano F. La Crosse virus (LACV) Gc fusion peptide mutants have impaired growth and fusion phenotypes, but remain neurotoxic. Virology 2010; 404:139-47. [PMID: 20553924 PMCID: PMC2919166 DOI: 10.1016/j.virol.2010.04.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 02/05/2010] [Accepted: 04/13/2010] [Indexed: 11/19/2022]
Abstract
La Crosse virus is a leading cause of pediatric encephalitis in the Midwestern United States and an emerging pathogen in the American South. The LACV glycoprotein Gc plays a critical role in entry as the virus attachment protein. A 22 amino acid hydrophobic region within Gc (1066-1087) was recently identified as the LACV fusion peptide. To further define the role of Gc (1066-1087) in virus entry, fusion, and neuropathogenesis, a panel of recombinant LACV (rLACV) fusion peptide mutant viruses was generated. Replication of mutant rLACVs was significantly reduced. In addition, the fusion peptide mutants demonstrated decreased fusion phenotypes relative to LACV-WT. Interestingly, these viruses maintained their ability to cause neuronal loss in culture, suggesting that the fusion peptide of LACV Gc is a determinant of properties associated with neuroinvasion (growth to high titer in muscle cells and a robust fusion phenotype), but not necessarily of neurovirulence.
Collapse
Affiliation(s)
- Samantha S Soldan
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-4283, USA.
| | | | | | | | | |
Collapse
|
38
|
E2F1 localizes predominantly to neuronal cytoplasm and fails to induce expression of its transcriptional targets in human immunodeficiency virus-induced neuronal damage. Neurosci Lett 2010; 479:97-101. [PMID: 20580656 DOI: 10.1016/j.neulet.2010.05.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/25/2010] [Accepted: 05/10/2010] [Indexed: 12/21/2022]
Abstract
As human immunodeficiency virus (HIV) does not induce neuronal damage by direct infection, the mechanisms of neuronal damage or loss in HIV-associated dementia (HAD) remain unclear. We have shown previously that immunoreactivity of transcription factor, E2F1, increases in neurons, localizing predominantly to the cytoplasm, in HIV-associated pathologies. Here we confirm that E2F1 localization is predominantly cytoplasmic in primary postmitotic neurons in vitro and cortical neurons in vivo. To determine whether E2F1 contributes to neuronal death in HAD via transactivation of target promoters, we assessed the mRNA and protein levels of several classical E2F1 transcriptional targets implicated in cell cycle progression and apoptosis in an in vitro model of HIV-induced neurotoxicity and in cortical autopsy tissue from patients infected with HIV. By Q-PCR, we show that mRNA levels of E2F1 transcriptional targets implicated in cell cycle progression (E2F1, Cyclin A, proliferating cell nuclear antigen (PCNA), and dyhydrofolate reductase (DHFR)) and apoptosis (caspases 3, 8, 9 and p19(ARF)) remain unchanged in an in vitro model of HIV-induced neurotoxicity. Further, we show that protein levels of p19(ARF), Cyclin A, and PCNA are not altered in vitro or in the cortex of patients with HAD. We propose that the predominantly cytoplasmic localization of E2F1 in neurons may account for the lack of E2F1 target transactivation in neurons responding to HIV-induced neurotoxicity.
Collapse
|
39
|
Bevers MB, Ingleton LP, Che D, Cole JT, Li L, Da T, Kopil CM, Cohen AS, Neumar RW. RNAi targeting micro-calpain increases neuron survival and preserves hippocampal function after global brain ischemia. Exp Neurol 2010; 224:170-7. [PMID: 20298691 DOI: 10.1016/j.expneurol.2010.03.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 12/24/2009] [Accepted: 03/05/2010] [Indexed: 10/19/2022]
Abstract
The calpain family of cysteine proteases has a well-established causal role in neuronal cell death following acute brain injury. However, the relative contribution of calpain isoforms has not been determined in in vivo models. Identification of the calpain isoform responsible for neuronal injury is particularly important given the differential role of calpain isoforms in normal physiology. This study evaluates the role of m-calpain and micro-calpain in an in vivo model of global brain ischemia. Adeno-associated viral vectors expressing short hairpin RNAs targeting the catalytic subunits of micro- or m-calpain were used to knockdown expression of the targeted isoforms in adult rat hippocampal CA1 pyramidal neurons. Knockdown of micro-calpain, but not m-calpain, prevented calpain activity 72 h after 6-min transient forebrain ischemia, increased long-term survival and protected hippocampal electrophysiological function. These findings represent the first in vivo evidence that reducing expression of an individual calpain isoform can decrease post-ischemic neuronal death and preserve hippocampal function.
Collapse
Affiliation(s)
- Matthew B Bevers
- Center for Resuscitation Science, Department of Emergency Medicine, University of Pennsylvania School of Medicine, Ground Ravdin, 3400 Spruce Street, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Tsang AH, Chung KK. Oxidative and nitrosative stress in Parkinson's disease. Biochim Biophys Acta Mol Basis Dis 2009; 1792:643-50. [DOI: 10.1016/j.bbadis.2008.12.006] [Citation(s) in RCA: 210] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 11/27/2008] [Accepted: 12/22/2008] [Indexed: 01/08/2023]
|
41
|
Abstract
Neural-cadherin (N-cadherin), a member of the classical cadherin family of transmembrane glycoproteins, mediates cellular recognition and cell-cell adhesion through calcium-dependent homophilic interactions and plays important roles in the development and maintenance of the nervous system. Metalloproteinase is known to cleave N-cadherin, which is further cleaved by gamma-secretase. The intracellular domain of N-cadherin interacts with beta-catenin, and beta-catenin stability is critical for cell-cell adhesion and cell survival. In the present study, we showed that N-cadherin is cleaved specifically by calpain, resulting in the generation of a novel 110 kDa fragment. The cleavage occurred in ischemic brain lesions and in vitro neural cells in the presence of NMDA and ionomycin, and was restored by calpain inhibitors but not matrix metalloproteinase or gamma-secretase inhibitors. Calpain directly cleaved N-cadherin in in vitro calpain assays, and calpain inhibitors prevented its cleavage in a dose-dependent manner. Using N-cadherin deletion mutants, we found that calpain cleavage sites exist in at least four regions of the cytoplasmic domain. Treatment with NMDA induced neuronal death, and it suppressed the expression of surface N-cadherin and the N-cadherin/beta-catenin interaction, effects that were prevented by calpain inhibitor. Furthermore, calpain-mediated N-cadherin cleavage significantly affected cell-cell adhesion, AKT signaling, the N-cadherin/beta-catenin interaction and the Wnt target gene expressions through the accumulation of nuclear beta-catenin.
Collapse
|
42
|
Crews L, Patrick C, Achim CL, Everall IP, Masliah E. Molecular pathology of neuro-AIDS (CNS-HIV). Int J Mol Sci 2009; 10:1045-1063. [PMID: 19399237 PMCID: PMC2672018 DOI: 10.3390/ijms10031045] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 03/05/2009] [Accepted: 03/09/2009] [Indexed: 11/17/2022] Open
Abstract
The cognitive deficits in patients with HIV profoundly affect the quality of life of people living with this disease and have often been linked to the neuro-inflammatory condition known as HIV encephalitis (HIVE). With the advent of more effective anti-retroviral therapies, HIVE has shifted from a sub-acute to a chronic condition. The neurodegenerative process in patients with HIVE is characterized by synaptic and dendritic damage to pyramidal neurons, loss of calbindin-immunoreactive interneurons and myelin loss. The mechanisms leading to neurodegeneration in HIVE might involve a variety of pathways, and several lines of investigation have found that interference with signaling factors mediating neuroprotection might play an important role. These signaling pathways include, among others, the GSK3beta, CDK5, ERK, Pyk2, p38 and JNK cascades. Of these, GSK3beta has been a primary focus of many previous studies showing that in infected patients, HIV proteins and neurotoxins secreted by immune-activated cells in the brain abnormally activate this pathway, which is otherwise regulated by growth factors such as FGF. Interestingly, modulation of the GSK3beta signaling pathway by FGF1 or GSK3beta inhibitors (lithium, valproic acid) is protective against HIV neurotoxicity, and several pilot clinical trials have demonstrated cognitive improvements in HIV patients treated with GSK3beta inhibitors. In addition to the GSK3beta pathway, the CDK5 pathway has recently been implicated as a mediator of neurotoxicity in HIV, and HIV proteins might activate this pathway and subsequently disrupt the diverse processes that CDK5 regulates, including synapse formation and plasticity and neurogenesis. Taken together, the GSK3beta and CDK5 signaling pathways are important regulators of neurotoxicity in HIV, and modulation of these factors might have therapeutic potential in the treatment of patients suffering from HIVE. In this context, the subsequent sections will focus on reviewing the involvement of the GSK3beta and CDK5 pathways in neurodegeneration in HIV.
Collapse
Affiliation(s)
- Leslie Crews
- Department of Pathology, University of California, San Diego / 9500 Gilman Dr. La Jolla, CA 92093, U.S.A.; E-Mail:
| | - Christina Patrick
- Department of Neurosciences, University of California, San Diego / 9500 Gilman Dr. La Jolla, CA 92093, U.S.A.; E-Mail:
| | - Cristian L. Achim
- Department of Psychiatry, University of California, San Diego / 9500 Gilman Dr. La Jolla, CA 92093, U.S.A.; E-Mails:
(C.A.);
(I.E.)
| | - Ian P. Everall
- Department of Psychiatry, University of California, San Diego / 9500 Gilman Dr. La Jolla, CA 92093, U.S.A.; E-Mails:
(C.A.);
(I.E.)
| | - Eliezer Masliah
- Department of Pathology, University of California, San Diego / 9500 Gilman Dr. La Jolla, CA 92093, U.S.A.; E-Mail:
- Department of Neurosciences, University of California, San Diego / 9500 Gilman Dr. La Jolla, CA 92093, U.S.A.; E-Mail:
- Author to whom correspondence should be addressed; E-Mail:
; Tel. +1 (858) 534-8992; Fax: +1 (858) 534-6232
| |
Collapse
|
43
|
Bevers MB, Lawrence E, Maronski M, Starr N, Amesquita M, Neumar RW. Knockdown of m-calpain increases survival of primary hippocampal neurons following NMDA excitotoxicity. J Neurochem 2009; 108:1237-50. [PMID: 19141074 DOI: 10.1111/j.1471-4159.2008.05860.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The calpain family of cysteine proteases has a well-established causal role in neuronal cell death following acute brain injury. However, the relative contribution of calpain isoforms to the various forms of injury has not been determined as available calpain inhibitors are not isoform-specific. In this study, we evaluated the relative role of m-calpain and mu-calpain in a primary hippocampal neuron model of NMDA-mediated excitotoxicity. Baseline mRNA expression for the catalytic subunit of m-calpain (capn2 ) was found to be 50-fold higher than for the mu-calpain catalytic subunit (capn1) based on quantitative real-time PCR. Adeno-associated viral vectors designed to deliver short hairpin RNAs targeting capn1 or capn2 resulted in 60% and 90% knockdown of message respectively. Knockdown of capn2 but not capn1 increased neuronal survival after NMDA exposure at 21 days in vitro. Nuclear translocation of calpain substrates apoptosis inducing factor, p35/p25 and collapsin response mediator protein (CRMP) 2-4 was not detected after NMDA exposure in this model. However, nuclear translocation of CRMP-1 was observed and was prevented by capn2 knockdown. These findings provide insight into potential mechanisms of calpain-mediated neurodegeneration and have important implications for the development of isoform-specific calpain inhibitor therapy.
Collapse
Affiliation(s)
- Matthew B Bevers
- Department of Emergency Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA
| | | | | | | | | | | |
Collapse
|
44
|
Martinez LB, Walsh SM, Jacobsen MT, Sato S, Wiederin J, Ciborowski P, Ikezu T. Calpain and proteasomal regulation of antiretroviral zinc finger protein OTK18 in human macrophages: visualization in live cells by intramolecular FRET. J Neuroimmune Pharmacol 2008; 4:116-28. [PMID: 19034669 DOI: 10.1007/s11481-008-9140-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 11/07/2008] [Indexed: 12/17/2022]
Abstract
As part of the innate immune defense against HIV infection, OTK18, a zinc finger protein, is upregulated in human macrophages and reduces viral replication through suppression of viral long-terminal repeat promoter activity. Although we know that the processing products of OTK18 accumulate in the cytoplasm of brain perivascular macrophages in advanced HIV encephalitis cases, the molecular mechanisms behind its post-translational processing are still poorly understood. To characterize OTK18 processing, we assessed a panel of protease inhibitors to identify the candidates involved in the OTK18 processing using human monocyte-derived macrophages (MDM) overexpressing OTK18 by recombinant adenoviral gene transfer. Viral infection of MDM strongly increased the processing of OTK18 into its N-terminal fragment. Treatment of OTK18-expressing MDM with calpain and proteasome inhibitors significantly accumulated either full-length or processed OTK18 fragments in time- and dose-dependent manners. A series of OTK18 truncation mutants and synthetic peptides were tested to locate the calpain cleavage sites after arginine 359. Finally, we developed an enhanced cyan and yellow fluorescent protein (ECFP and EYFP)-based intramolecular fluorescent resonance energy transfer (intramolecular FRET) system to monitor the OTK18 endoproteolysis in human microglia cell line. Inhibition of proteasome activity significantly increased the intramolecular FRET signal in the nucleus. These data suggest that calpain and proteasome are involved in OTK18 endoproteolysis and degradation. Additionally, intramolecular FRET has proven to be a useful tool for monitoring the processing in live cells.
Collapse
Affiliation(s)
- Lindsey B Martinez
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5880, USA
| | | | | | | | | | | | | |
Collapse
|
45
|
Alirezaei M, Kiosses WB, Fox HS. Decreased neuronal autophagy in HIV dementia: a mechanism of indirect neurotoxicity. Autophagy 2008; 4:963-6. [PMID: 18772620 PMCID: PMC2665179 DOI: 10.4161/auto.6805] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Many recent studies indicate that dysregulation of autophagy is a common feature of many neurodegenerative diseases. The HIV-1-associated neurological disorder is an acquired cognitive and motor disease that includes a severe neurodegenerative dementia. We find that the neurodegeneration seen in the brain in HIV-1 infection is associated with an inhibition of neuronal autophagy, leading to neuronal demise. Neurons treated with supernatants from SIV-infected microglia develop a decrease in autophagy-inducing proteins, a decrease in neuronal autophagy vesicles, and an increase in sequestosome-1/p62. Examination of brains from HIV-infected individuals and SIV-infected monkeys reveals signs of autophagy dysregulation, associated, respectively, with dementia and encephalitis. Excitotoxic and inflammatory factors could inhibit neuronal autophagy, and stimulation of autophagy with rapamycin prevents such effects. Here we amplify on these findings, and propose that in the setting of HIV-infection, the decreased neuronal autophagy sensitizes cells to pro-apoptotic and other damaging mechanisms, leading to neuronal dysfunction and death. Hence, new therapeutic approaches aimed at boosting neuronal autophagy are conceivable to treat those suffering from the neurological complications of HIV.
Collapse
Affiliation(s)
- Mehrdad Alirezaei
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California, USA
| | | | | |
Collapse
|
46
|
Alirezaei M, Kiosses WB, Flynn CT, Brady NR, Fox HS. Disruption of neuronal autophagy by infected microglia results in neurodegeneration. PLoS One 2008; 3:e2906. [PMID: 18682838 PMCID: PMC2483417 DOI: 10.1371/journal.pone.0002906] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 07/15/2008] [Indexed: 12/14/2022] Open
Abstract
There is compelling evidence to support the idea that autophagy has a protective function in neurons and its disruption results in neurodegenerative disorders. Neuronal damage is well-documented in the brains of HIV-infected individuals, and evidence of inflammation, oxidative stress, damage to synaptic and dendritic structures, and neuronal loss are present in the brains of those with HIV-associated dementia. We investigated the role of autophagy in microglia-induced neurotoxicity in primary rodent neurons, primate and human models. We demonstrate here that products of simian immunodeficiency virus (SIV)-infected microglia inhibit neuronal autophagy, resulting in decreased neuronal survival. Quantitative analysis of autophagy vacuole numbers in rat primary neurons revealed a striking loss from the processes. Assessment of multiple biochemical markers of autophagic activity confirmed the inhibition of autophagy in neurons. Importantly, autophagy could be induced in neurons through rapamycin treatment, and such treatment conferred significant protection to neurons. Two major mediators of HIV-induced neurotoxicity, tumor necrosis factor-alpha and glutamate, had similar effects on reducing autophagy in neurons. The mRNA level of p62 was increased in the brain in SIV encephalitis and as well as in brains from individuals with HIV dementia, and abnormal neuronal p62 dot structures immunoreactivity was present and had a similar pattern with abnormal ubiquitinylated proteins. Taken together, these results identify that induction of deficits in autophagy is a significant mechanism for neurodegenerative processes that arise from glial, as opposed to neuronal, sources, and that the maintenance of autophagy may have a pivotal role in neuroprotection in the setting of HIV infection.
Collapse
Affiliation(s)
- Mehrdad Alirezaei
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California, United States of America
| | - William B. Kiosses
- Core Microscopy Facility, The Scripps Research Institute, La Jolla, California, United States of America
| | - Claudia T. Flynn
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California, United States of America
| | - Nathan R. Brady
- Deutsches Krebsforschungszentrum and BIOQUANT, Heidelberg, Germany
| | - Howard S. Fox
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
| |
Collapse
|
47
|
Cagnon L, Braissant O. Role of caspases, calpain and cdk5 in ammonia-induced cell death in developing brain cells. Neurobiol Dis 2008; 32:281-92. [PMID: 18722528 DOI: 10.1016/j.nbd.2008.07.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 06/23/2008] [Accepted: 07/14/2008] [Indexed: 11/26/2022] Open
Abstract
Hyperammonemia in neonates and infants causes irreversible damages in the developing CNS due to brain cell loss. Elucidating the mechanisms triggering ammonia-induced cell death in CNS is necessary for the development of neuroprotective strategies. We used reaggregated developing brain cell cultures derived from fetal rat telencephalon exposed to ammonia as an experimental model. Ammonia induced neuronal and oligodendroglial death, triggered apoptosis and activated caspases and calpain. Probably due to calpain activation, ammonia caused the cleavage of the cyclin-dependent kinase 5 activator, p35, to p25, the cdk5/p25 complex being known to lead to neurodegeneration. Roscovitine, a cdk5 inhibitor, protected neurons from ammonia-induced cell death. However, roscovitine also impaired axonal growth, probably through inhibition of the remaining cdk5/p35 activity, which is involved in neurite outgrowth. Thus, cdk5 appears as a promising therapeutic target for treating hyperammonemic newborns and infants, especially if one develops specific cdk5/p25 inhibitors.
Collapse
Affiliation(s)
- Laurène Cagnon
- Inborn Errors of Metabolism, Clinical Chemistry Laboratory, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Switzerland
| | | |
Collapse
|
48
|
Enhanced tau phosphorylation in the hippocampus of mice treated with 3,4-methylenedioxymethamphetamine ("Ecstasy"). J Neurosci 2008; 28:3234-45. [PMID: 18354027 DOI: 10.1523/jneurosci.0159-08.2008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
3,4-Methylenedioxymethamphetamine (MDMA) ("Ecstasy") produces neurotoxic effects, which result into an impairment of learning and memory and other neurological dysfunctions. We examined whether MDMA induces increases in tau protein phosphorylation, which are typically associated with Alzheimer's disease and other chronic neurodegenerative disorders. We injected mice with MDMA at cumulative doses of 10-50 mg/kg intraperitoneally, which are approximately equivalent to doses generally consumed by humans. MDMA enhanced the formation of reactive oxygen species and induced reactive gliosis in the hippocampus, without histological evidence of neuronal loss. An acute or 6 d treatment with MDMA increased tau protein phosphorylation in the hippocampus, revealed by both anti-phospho(Ser(404))-tau and paired helical filament-1 antibodies. This increase was restricted to the CA2/CA3 subfields and lasted 1 and 7 d after acute and repeated MDMA treatment, respectively. Tau protein was phosphorylated as a result of two nonredundant mechanisms: (1) inhibition of the canonical Wnt (wingless-type MMTV integration site family) pathway, with ensuing activation of glycogen synthase kinase-3beta; and (2) activation of type-5 cyclin-dependent kinase (Cdk5). MDMA induced the expression of the Wnt antagonist, Dickkopf-1, and the expression of the Cdk5-activating protein, p25. In addition, the increase in tau phosphorylation was attenuated by strategies that rescued the Wnt pathway or inhibited Cdk5. Finally, an impairment in hippocampus-dependent spatial learning was induced by doses of MDMA that increased tau phosphorylation, although the impairment outlasted this biochemical event. We conclude that tau hyperphosphorylation in the hippocampus may contribute to the impairment of learning and memory associated with MDMA abuse.
Collapse
|