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Joshi SM, Jadavji NM. Deficiencies in one-carbon metabolism led to increased neurological disease risk and worse outcome: homocysteine is a marker of disease state. Front Nutr 2024; 11:1285502. [PMID: 38450239 PMCID: PMC10915003 DOI: 10.3389/fnut.2024.1285502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 02/12/2024] [Indexed: 03/08/2024] Open
Abstract
Elevated plasma homocysteine levels have been identified as a significant, independent risk factor for the development of cognitive decline including Alzheimer's disease. While several studies have explored the link between homocysteine and disease risk, the associations have not been entirely clear. Elevated levels of homocysteine serve as a disease marker and understanding the underlying cause of these increased levels (e.g., dietary or genetic deficiency in one-carbon metabolism, 1C) will provide valuable insights into neurological disease risk and outcomes. Previous cell culture experiments investigating the mechanisms involved used ultra-high levels of homocysteine that are not observed in human patients. These studies have demonstrated the negative impacts of ultra-high levels of homocysteine can have on for example proliferation of neuroprogenitor cells in the adult hippocampus, as well as triggering neuronal apoptosis through a series of events, including DNA damage, PARP activation, NAD depletion, mitochondrial dysfunction, and oxidative stress. The aim of this mini-review article will summarize the literature on deficiencies in 1C and how they contribute to disease risk and outcomes and that homocysteine is a marker of disease.
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Affiliation(s)
- Sanika M. Joshi
- College of Osteopathic Medicine, Midwestern University, Glendale, AZ, United States
- Department of Biomedical Sciences, Midwestern University, Glendale, AZ, United States
| | - Nafisa M. Jadavji
- College of Osteopathic Medicine, Midwestern University, Glendale, AZ, United States
- Department of Biomedical Sciences, Midwestern University, Glendale, AZ, United States
- Department of Child Health, College of Medicine – Phoenix, University of Arizona, Phoenix, AZ, United States
- College of Veterinary Medicine, Midwestern University, Glendale, AZ, United States
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
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2
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Bou Ghanem A, Hussayni Y, Kadbey R, Ratel Y, Yehya S, Khouzami L, Ghadieh HE, Kanaan A, Azar S, Harb F. Exploring the complexities of 1C metabolism: implications in aging and neurodegenerative diseases. Front Aging Neurosci 2024; 15:1322419. [PMID: 38239489 PMCID: PMC10794399 DOI: 10.3389/fnagi.2023.1322419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/11/2023] [Indexed: 01/22/2024] Open
Abstract
The intricate interplay of one-carbon metabolism (OCM) with various cellular processes has garnered substantial attention due to its fundamental implications in several biological processes. OCM serves as a pivotal hub for methyl group donation in vital biochemical reactions, influencing DNA methylation, protein synthesis, and redox balance. In the context of aging, OCM dysregulation can contribute to epigenetic modifications and aberrant redox states, accentuating cellular senescence and age-associated pathologies. Furthermore, OCM's intricate involvement in cancer progression is evident through its capacity to provide essential one-carbon units crucial for nucleotide synthesis and DNA methylation, thereby fueling uncontrolled cell proliferation and tumor development. In neurodegenerative disorders like Alzheimer's and Parkinson's, perturbations in OCM pathways are implicated in the dysregulation of neurotransmitter synthesis and mitochondrial dysfunction, contributing to disease pathophysiology. This review underscores the profound impact of OCM in diverse disease contexts, reinforcing the need for a comprehensive understanding of its molecular complexities to pave the way for targeted therapeutic interventions across inflammation, aging and neurodegenerative disorders.
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Affiliation(s)
- Ayman Bou Ghanem
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Yaman Hussayni
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Raghid Kadbey
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Yara Ratel
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Shereen Yehya
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Lara Khouzami
- College of Natural and Health Sciences, Zayed University, Dubai, United Arab Emirates
| | - Hilda E. Ghadieh
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
- AUB Diabetes, American University of Beirut Medical Center, Beirut, Lebanon
| | - Amjad Kanaan
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Sami Azar
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
| | - Frederic Harb
- Faculty of Medicine and Medical Sciences, University of Balamand, Tripoli, Lebanon
- AUB Diabetes, American University of Beirut Medical Center, Beirut, Lebanon
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3
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Carpita B, Massoni L, Battaglini S, Palego L, Cremone IM, Massimetti G, Betti L, Giannaccini G, Dell'Osso L. IL-6, homocysteine, and autism spectrum phenotypes: an investigation among adults with autism spectrum disorder and their first-degree relatives. CNS Spectr 2023; 28:620-628. [PMID: 36690583 DOI: 10.1017/s1092852923000019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND The importance of recognizing different kinds of autism spectrum presentations among adults, including subthreshold forms and the broad autism phenotype (BAP), has been increasingly highlighted in recent studies. Meanwhile, the possible involvement of immune system deregulation and altered methylation/trans-sulfuration processes in autism spectrum disorder (ASD) is gaining growing attention, but studies in this field are mainly focused on children. In this framework, the aim of this study was to compare plasmatic concentrations of IL-6 and homocysteine (HCY) among adults with ASD, their first-degree relatives, and healthy controls (CTLs), investigating also possible correlations with specific autism symptoms. METHODS Plasma concentrations of IL-6 and HCY were measured in a group of adult subjects with ASD, their first-degree relatives (BAP group), and healthy controls (CTL). All participants were also evaluated with psychometric instruments. RESULTS IL-6 and HCY concentrations were significantly higher in the ASD group than in CTLs, while BAP subjects reported intermediate results. Significant correlations were reported between biochemical parameters and psychometric scales, particularly for the dimension of ruminative thinking. CONCLUSIONS These findings support the hypothesis of a key involvement of HCY-related metabolism and immune system alteration in autism spectrum pathophysiology. HCY and IL-6 seem to show different associations with specific autism dimensions.
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Affiliation(s)
- Barbara Carpita
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Leonardo Massoni
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Simone Battaglini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | | | - Ivan M Cremone
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Gabriele Massimetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Laura Betti
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | | | - Liliana Dell'Osso
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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4
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Townsend LN, Clarke H, Maddison D, Jones KM, Amadio L, Jefferson A, Chughtai U, Bis DM, Züchner S, Allen ND, Van der Goes van Naters W, Peters OM, Smith GA. Cdk12 maintains the integrity of adult axons by suppressing actin remodeling. Cell Death Discov 2023; 9:348. [PMID: 37730761 PMCID: PMC10511712 DOI: 10.1038/s41420-023-01642-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/25/2023] [Accepted: 09/07/2023] [Indexed: 09/22/2023] Open
Abstract
The role of cyclin-dependent kinases (CDKs) that are ubiquitously expressed in the adult nervous system remains unclear. Cdk12 is enriched in terminally differentiated neurons where its conical role in the cell cycle progression is redundant. We find that in adult neurons Cdk12 acts a negative regulator of actin formation, mitochondrial dynamics and neuronal physiology. Cdk12 maintains the size of the axon at sites proximal to the cell body through the transcription of homeostatic enzymes in the 1-carbon by folate pathway which utilize the amino acid homocysteine. Loss of Cdk12 leads to elevated homocysteine and in turn leads to uncontrolled F-actin formation and axonal swelling. Actin remodeling further induces Drp1-dependent fission of mitochondria and the breakdown of axon-soma filtration barrier allowing soma restricted cargos to enter the axon. We demonstrate that Cdk12 is also an essential gene for long-term neuronal survival and loss of this gene causes age-dependent neurodegeneration. Hyperhomocysteinemia, actin changes, and mitochondrial fragmentation are associated with several neurodegenerative conditions such as Alzheimer's disease and we provide a candidate molecular pathway to link together such pathological events.
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Affiliation(s)
- L N Townsend
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
| | - H Clarke
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - D Maddison
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - K M Jones
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
| | - L Amadio
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - A Jefferson
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - U Chughtai
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - D M Bis
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, USA
| | - S Züchner
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, USA
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, USA
| | - N D Allen
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
| | | | - O M Peters
- School of Biosciences, Cardiff University, Cardiff, CF24 4HQ, UK
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK
| | - G A Smith
- School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK.
- UK Dementia Research Institute, Cardiff University, Cardiff, CF24 4HQ, UK.
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5
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Silveira JS, Júnior OVR, Schmitz F, Ferreira FS, Rodrigues FC, Deon M, Ribas G, Coutinho-Silva R, Vargas CR, Savio LEB, Wyse AT. High-protein nutrition during pregnancy increases neuroinflammation and homocysteine levels and impairs behavior in male adolescent rats offspring. Life Sci 2022; 310:121084. [DOI: 10.1016/j.lfs.2022.121084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/04/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022]
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6
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Heimfarth L, Nascimento LDS, Amazonas da Silva MDJ, Lucca Junior WD, Lima ES, Quintans-Junior LJ, Veiga-Junior VFD. Neuroprotective and anti-inflammatory effect of pectolinarigenin, a flavonoid from Amazonian Aegiphila integrifolia (Jacq.), against lipopolysaccharide-induced inflammation in astrocytes via NFκB and MAPK pathways. Food Chem Toxicol 2021; 157:112538. [PMID: 34500010 DOI: 10.1016/j.fct.2021.112538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/21/2021] [Accepted: 09/03/2021] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases affect millions of people worldwide. Regardless of the underlying cause, neuroinflammation is the greatest risk factor for developing any of these disorders. Pectolinarigenin (PNG) is an active flavonoid with several biological properties, anti-metastatic and anti-inflammatory activity. This study investigate the biological effects of PNG in macrophage and astrocyte cultures, with focus on elucidating the molecular mechanisms involved in the PNG activity. J774A.1 murine macrophage or cerebral cortex primary astrocytes primary cultures were treated with different concentration of PNG (1-160 μM) and the inflammatory process was stimulated by LPS (1 μg/ml) and the effect of PNG in different inflammatory markers were determined. PNG did not affect astrocyte or macrophage viability. Moreover, this flavonoid reduced NO• release in macrophages, attenuated astrocyte activation by preventing the overexpression of glial fibrillary acidic protein, and decreased the release of inflammatory mediators, IL-1β and IL-6 induced by LPS by the glial cell, as well as enhanced basal levels of IL-10. In addition, PNG suppressed NFκB, p38MAPK and ERK1/2 phosphorylation in astrocytes culture induced by LPS. The results show clear evidence that this novel flavonoid protects astrocytes against LPS-induced inflammatory toxicity. In conclusion, PNG presents neuroprotective and anti-inflammatory property through the inhibition of inflammatory signaling pathways.
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Affiliation(s)
- Luana Heimfarth
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | | | | | | | - Emerson Silva Lima
- Faculty of Pharmaceutical Sciences, Federal University of Amazonas, Manaus, AM, Brazil
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7
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Vazi EPG, Holanda F, Santos NA, Cardoso CV, Martins MFM, Bondan EF. Short-term systemic methotrexate administration in rats induces astrogliosis and microgliosis. Res Vet Sci 2021; 138:39-48. [PMID: 34091228 DOI: 10.1016/j.rvsc.2021.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 10/21/2022]
Abstract
Methotrexate (MTX), an antifolate drug, is widely used in chemotherapeutic protocols for metastatic and primary brain tumors and some autoimmune diseases. Its efficacy for brain tumors is limited by the high incidence of central nervous system (CNS) complications. This investigation aimed to observe the morphological effects, including astroglial and microglial responses, following systemic short-term MTX administration in adult rats. Male Wistar rats received 5 or 10 mg/kg/day of MTX by intraperitoneal route for 4 consecutive days (respectively, MTX5 and MTX10 groups) or the same volume of 0.9% saline solution (control group). On the 5th day, brain samples were collected for hematoxylin-eosin and luxol fast blue staining techniques, as well as for immunohistochemical staining for glial fibrillary acidic protein (GFAP) expression in astrocytes and Iba1 (ionized calcium binding adaptor molecule 1) for microglia in the frontal cortex, hippocampus, hypothalamus and molecular/granular layers of the cerebellum. Morphometric analyses were performed using Image Pro-Plus software. Brain levels of the proinflammatory cytokines TNF-α and IL-1β were determined by ELISA. No signs of neuronal loss or demyelination were observed in all groups. Increased GFAP and Iba1 expression was found in all areas from the MTX groups, although it was slightly higher in the MTX10 group compared to the MTX5. Both TNF-α and IL-1β levels were decreased in the MTX5 group compared to controls. In the MTX10 group, TNF-α decreased, although IL-1β was increased relative to controls. MTX administration induced microglial reaction and astrogliosis in several CNS areas. In the MTX5 group, it apparently occurred in the presence of decreased proinflammatory cytokines.
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Affiliation(s)
- E P G Vazi
- Graduate Program in Environmental and Experimental Pathology, University Paulista, São Paulo, SP, Brazil
| | - F Holanda
- Department of Veterinary Medicine, University Cruzeiro do Sul, São Paulo, SP, Brazil
| | - N A Santos
- Graduate Program in Environmental and Experimental Pathology, University Paulista, São Paulo, SP, Brazil
| | - C V Cardoso
- Graduate Program in Environmental and Experimental Pathology, University Paulista, São Paulo, SP, Brazil
| | - M F M Martins
- Department of Veterinary Medicine, University Cruzeiro do Sul, São Paulo, SP, Brazil
| | - E F Bondan
- Graduate Program in Environmental and Experimental Pathology, University Paulista, São Paulo, SP, Brazil; Department of Veterinary Medicine, University Cruzeiro do Sul, São Paulo, SP, Brazil.
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8
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Wyse ATS, Bobermin LD, Dos Santos TM, Quincozes-Santos A. Homocysteine and Gliotoxicity. Neurotox Res 2021; 39:966-974. [PMID: 33786757 DOI: 10.1007/s12640-021-00359-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/21/2021] [Accepted: 03/23/2021] [Indexed: 12/15/2022]
Abstract
Homocysteine is a sulfur amino acid that does not occur in the diet, but it is an essential intermediate in normal mammalian metabolism of methionine. Hyperhomocysteinemia results from dietary intakes of Met, folate, and vitamin B12 and lifestyle or from the deficiency of specific enzymes, leading to tissue accumulation of this amino acid and/or its metabolites. Severe hyperhomocysteinemic patients can present neurological symptoms and structural brain abnormalities, of which the pathogenesis is poorly understood. Moreover, a possible link between homocysteine (mild hyperhomocysteinemia) and neurodegenerative/neuropsychiatric disorders has been suggested. In recent years, increasing evidence has emerged suggesting that astrocyte dysfunction is involved in the neurotoxicity of homocysteine and possibly associated with the physiopathology of hyperhomocysteinemia. This review addresses some of the findings obtained from in vivo and in vitro experimental models, indicating high homocysteine levels as an important neurotoxin determinant of the neuropathophysiology of brain damage. Recent data show that this amino acid impairs glutamate uptake, redox/mitochondrial homeostasis, inflammatory response, and cell signaling pathways. Therefore, the discussion of this review focuses on homocysteine-induced gliotoxicity, and its impacts in the brain functions. Through understanding the Hcy-induced gliotoxicity, novel preventive/therapeutic strategies might emerge for these diseases.
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Affiliation(s)
- Angela T S Wyse
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. .,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
| | - Larissa Daniele Bobermin
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Tiago Marcon Dos Santos
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - André Quincozes-Santos
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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9
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Homocysteine in Schizophrenia: Independent Pathogenetic Factor with Prooxidant Activity or Integral Marker of Other Biochemical Disturbances? SCHIZOPHRENIA RESEARCH AND TREATMENT 2021; 2021:7721760. [PMID: 34707909 PMCID: PMC8545596 DOI: 10.1155/2021/7721760] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 09/20/2021] [Accepted: 10/05/2021] [Indexed: 01/21/2023]
Abstract
A wide range of studies have demonstrated that hyperhomocysteinemia is associated with the risk of schizophrenia, but currently available assumptions about the direct involvement of homocysteine (Hcy) in the pathogenesis of schizophrenia are hypothetical. It is possible that in vivo Hcy is only a marker of folate metabolism disturbances (which are involved in methylation processes) and is not a pathogenetic factor per se. Only one study has been conducted in which associations of hyperhomocysteinemia with oxidative stress in schizophrenia (oxidative damage to protein and lipids) have been found, and it has been suggested that the oxidative stress may be induced by the elevated Hcy in schizophrenic patients. But the authors did not study the level of reduced glutathione (GSH), as well as possible causes of hyperhomocysteinemia-disturbances of folate metabolism. The aim of this work is to analyze the association of Hcy levels with the following: (1) redox markers in schizophrenia GSH, markers of oxidative damage of proteins and lipids, and the activity of antioxidant enzymes in blood serum; (2) with the level of folate and cobalamin (В12); and (3) with clinical features of schizophrenia measured using the Positive and Negative Syndrome Scale (PANSS). 50 patients with schizophrenia and 36 healthy volunteers, matched by sex and age, were examined. Hcy in patients is higher than in healthy subjects (p = 0.0041), and this may be due to the lower folate level in patients (p = 0.0072). In patients, negative correlation was found between the level of Hcy both with the level of folate (ρ = -0.38, p = 0.0063) and with the level of B12 (ρ = -0.36, p = 0.0082). At the same time, patients showed higher levels of oxidative modification of serum proteins (p = 0.00046) and lower catalase (CAT) activity (p = 0.014). However, Hcy is not associated with the studied markers of oxidative stress in patients. In the group of patients with an increased level of Hcy (>10 μmol/l, n = 42) compared with other patients (n = 8), some negative symptoms (PANSS) were statistically significantly more pronounced: difficulty in abstract thinking (N5, p = 0.019), lack of spontaneity and flow in conversation (N6, p = 0.022), stereotyped thinking (N7, p = 0.013), and motor retardation (G7, p = 0.050). Thus, in patients with schizophrenia, hyperhomocysteinemia caused by deficiency of folate and B12 is confirmed and can be considered a marker of disturbances of vitamin metabolism. The redox imbalance is probably not directly related to hyperhomocysteinemia and is hypothetically caused by other pathological processes or by an indirect effect of Hcy, for example, on the enzymatic antioxidant defence system (CAT activity), which requires further exploration. Further study of the role of Hcy in the pathogenesis of schizophrenia is relevant, since the proportion of patients with hyperhomocysteinemia is high and correlations of its level with negative symptoms of schizophrenia are noted.
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10
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Abato JE, Moftah M, Cron GO, Smith PD, Jadavji NM. Methylenetetrahydrofolate reductase deficiency alters cellular response after ischemic stroke in male mice. Nutr Neurosci 2020; 25:558-566. [PMID: 32448097 DOI: 10.1080/1028415x.2020.1769412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Objective: Elevated homocysteine concentrations are a risk factor for stroke. A common genetic polymorphism in methylenetetrahydrofolate reductase (MTHFR 677 C→T) results in elevated levels of homocysteine. MTHFR plays a critical role in the synthesis of S-adenosylmethionine (SAM), a global methyl donor. Our previous work has demonstrated that Mthfr+/- mice, which model the MTHFR polymorphism in humans, are more vulnerable to ischemic damage. The aim of this study was to investigate the cellular mechanisms by which the MTHFR-deficiency changes the brain in the context of ischemic stroke injury.Methods: In the present study, three-month-old male Mthfr+/- and wild-type littermate mice were subjected to photothrombosis (PT) damage. Four weeks after PT damage, animals were tested on behavioral tasks, in vivo imaging was performed using T2-weighted MRI, and brain tissue was collected for histological analysis.Results: Mthfr+/- animals used their non-impaired forepaw more to explore the cylinder and had a larger damage volume compared to wild-type littermates. In brain tissue of Mthfr+/- mice methionine adenosyltransferase II alpha (MAT2A) protein levels were decreased within the damage hemisphere and increased levels in hypoxia-induced factor 1 alpha (HIF-1α) in non-damage hemisphere. There was an increased antioxidant response in the damage site as indicated by higher levels of nuclear factor erythroid 2-related factor 2 (Nrf2) in neurons and astrocytes and neuronal superoxide dismutase 2 (SOD2) levels.Conclusions: Our results suggest that Mthfr+/- mice are more vulnerable to PT-induced stroke damage through the regulation of the cellular response. The increased antioxidant response we observed may be compensatory to the damage amount.
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Affiliation(s)
- Jamie E Abato
- Department of Biomedical Sciences, Midwestern University, Glendale, AZ, USA
| | - Mahira Moftah
- Department of Neuroscience, Carleton University, Ottawa, Canada
| | - Greg O Cron
- Department of Radiology, University of Ottawa, Ottawa, Canada.,The Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Medical Imaging, The Ottawa Hospital, Ottawa, Canada
| | - Patrice D Smith
- Department of Neuroscience, Carleton University, Ottawa, Canada
| | - Nafisa M Jadavji
- Department of Biomedical Sciences, Midwestern University, Glendale, AZ, USA.,Department of Neuroscience, Carleton University, Ottawa, Canada
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11
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Synaptic remodeling and reduced expression of the transcription factors, HES1 and HES5, in the cortex neurons of cognitively impaired hyperhomocysteinemic mice. Pathol Res Pract 2020; 216:152953. [PMID: 32345540 DOI: 10.1016/j.prp.2020.152953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/17/2020] [Accepted: 03/29/2020] [Indexed: 11/22/2022]
Abstract
Hyperhomocysteinemia (HHcy) is associated with cognitive impairment and neurodegenerative diseases. The synaptic ultrastructure and the expression of hairy enhancer of split (HES) genes are involved in cognitive impairment induced by HHcy, but their precise role remains unclear. The present study aimed to measure synaptic remodeling and the expression of HES1 and HES5 in the cortex neurons of mice with HHcy to clarify their role in cognitive impairment. Mild HHcy was induced in ApoE-/- mice receiving a high-methionine diet. The correct response percentage, latency, and distance traveled in the mice with HHcy decreased compared with those of non-HHcy control mice (P < 0.05). There was no difference in the neuronal counts and the mean optical density of Nissl bodies in the frontal cortex of HHcy and non-HHcy mice. Increased apoptosis rates and numbers of autophagosomes were observed in the HHcy mice by TUNEL staining and electron microscopy, respectively, compared to those in the control group (P < 0.05). There was a significant increase in the area of postsynaptic density and size variation of synaptic vesicles in the HHcy group compared to that in the control (P < 0.05). Decreased expression of HES1 and HES5 was observed by western blotting and immunostaining in the HHcy group compared to that in the control (P < 0.05). Collectively, these results suggest that increased autophagy, apoptosis, synaptic remodeling, and downregulation of hes1 and hes5 are involved in the cognitive impairment induced by hyperhomocysteinemia.
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12
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Exposure to homocysteine leads to cell cycle damage and reactive gliosis in the developing brain. Reprod Toxicol 2019; 87:60-69. [PMID: 31082465 DOI: 10.1016/j.reprotox.2019.05.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 04/15/2019] [Accepted: 05/09/2019] [Indexed: 01/19/2023]
Abstract
Studies that investigate the cellular effects of homocysteine (Hcy) on the differentiation of neural cells, and their involvement in establishment of cell layers in the developing brain are scarce. This study evaluated how Hcy affects the neural cell cycle and proteins involved in neuronal differentiation in the telencephalon and mesencephalon using the chicken embryo as a model. Embryos at embryonic day 2 (E2) received 20 μmol D-L Hcy/50 μl saline and analyzed at E6. The Hcy treatment induced an increase in the ventricular length of the telencephalon and also a reduction of the mantle layer thickness. We observed that Hcy induced impairments to the neural cell cycle and differentiation, which compromised the cell layers establishment in the developing brain. Hcy treatment also induced changes in gene and protein expression of astrocytes, characteristic of reactive gliosis. Our results point to new perspectives of evaluation of cellular targets of Hcy toxicity.
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Association of Induced Hyperhomocysteinemia with Alzheimer's Disease-Like Neurodegeneration in Rat Cortical Neurons After Global Ischemia-Reperfusion Injury. Neurochem Res 2018; 43:1766-1778. [PMID: 30003389 DOI: 10.1007/s11064-018-2592-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/25/2018] [Accepted: 07/05/2018] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder that results in massive hippocampal and neocortical neuronal loss leading to dementia and eventual death. The exact cause of Alzheimer's disease is not fully explored, although a number of risk factors have been recognized, including high plasma concentration of homocysteine (Hcy). Hyperhomocysteinemia (hHcy) is considered a strong, independent risk factor for stroke and dementia. However, the molecular background underlying these mechanisms linked with hHcy and ischemic stroke is not fully understood. Paper describes rat model of global forebrain ischemia combined with the experimentally induced hHcy. Global ischemia-reperfusion injury (IRI) was developed by 4-vessels occlusion lasting for 15 min followed by reperfusion period of 72 h. hHcy was induced by subcutaneous injection of 0.45 µmol/g of Hcy in duration of 14 days. The results showed remarkable neural cell death induced by hHcy in the brain cortex and neurodegeneration is further aggravated by global IRI. We demonstrated degeneration of cortical neurons, alterations in number and morphology of tissue astrocytes and dysregulation of oxidative balance with increased membrane protein oxidation. Complementary to, an immunohistochemical analysis of tau protein and β-amyloid peptide showed that combination of hHcy with the IRI might lead to the progression of AD-like pathological features. Conclusively, these findings suggest that combination of risk factor hHcy with IRI aggravates neurodegeneration processes and leads to development of AD-like pathology in cerebral cortex.
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Schmitz F, Pierozan P, Biasibetti-Brendler H, Ferreira FS, Dos Santos Petry F, Trindade VMT, Pessoa-Pureur R, Wyse ATS. Methylphenidate disrupts cytoskeletal homeostasis and reduces membrane-associated lipid content in juvenile rat hippocampus. Metab Brain Dis 2018; 33:693-704. [PMID: 29288365 DOI: 10.1007/s11011-017-0177-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Accepted: 12/25/2017] [Indexed: 12/16/2022]
Abstract
Although methylphenidate (MPH) is ubiquitously prescribed to children and adolescents, the consequences of chronic utilization of this psychostimulant are poorly understood. In this study, we investigated the effects of MPH on cytoskeletal homeostasis and lipid content in rat hippocampus. Wistar rats received intraperitoneal injections of MPH (2.0 mg/kg) or saline solution (controls), once a day, from the 15th to the 44th day of age. Results showed that MPH provoked hypophosphorylation of glial fibrillary acidic protein (GFAP) and reduced its immunocontent. Middle and high molecular weight neurofilament subunits (NF-M, NF-H) were hypophosphorylated by MPH on KSP repeat tail domains, while NFL, NFM and NFH immunocontents were not altered. MPH increased protein phosphatase 1 (PP1) and 2A (PP2A) immunocontents. MPH also decreased the total content of ganglioside and phospholipid, as well as the main brain gangliosides (GM1, GD1a, and GD1b) and the major brain phospholipids (sphingomyelin, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine). Total cholesterol content was also reduced in the hippocampi of juvenile rats treated with MPH. These results provide evidence that disruptions of cytoskeletal and lipid homeostasis in hippocampus of juvenile rats are triggers by chronic MPH treatment and present a new basis for understanding the effects and consequences associated with chronic use of this psychostimulant during the development of the central nervous system.
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Affiliation(s)
- Felipe Schmitz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Paula Pierozan
- Laboratório de Neuroproteção e Doenças Metabólicas, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, CEP 90035-003, Brazil
| | - Helena Biasibetti-Brendler
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fernanda Silva Ferreira
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fernanda Dos Santos Petry
- Laboratório de Bioquímica e Biologia Celular de Lipídios, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Vera Maria Treis Trindade
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Laboratório de Bioquímica e Biologia Celular de Lipídios, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Regina Pessoa-Pureur
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Laboratório do Citoesqueleto, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Angela T S Wyse
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
- Laboratório de Neuroproteção e Doenças Metabólicas, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, CEP 90035-003, Brazil.
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15
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Combination Therapy with Sulfasalazine and Valproic Acid Promotes Human Glioblastoma Cell Death Through Imbalance of the Intracellular Oxidative Response. Mol Neurobiol 2018; 55:6816-6833. [PMID: 29349577 DOI: 10.1007/s12035-018-0895-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 01/09/2018] [Indexed: 01/15/2023]
Abstract
Glioblastoma (GBM) is the most common and aggressive malignant primary brain tumor and still lacks effective therapeutic strategies. It has already been shown that old drugs like sulfasalazine (SAS) and valproic acid (VPA) present antitumoral activities in glioma cell lines. SAS has also been associated with a decrease of intracellular glutathione (GSH) levels through a potent inhibition of xc- glutamate/cystine exchanger leading to an antioxidant deprotection. In the same way, VPA was recently identified as a histone deacetylase (HDAT) inhibitor capable of activating tumor suppression genes. As both drugs are widely used in clinical practice and their profile of adverse effects is well known, the aim of our study was to investigate the effects of the combined treatment with SAS and VPA in GBM cell lines. We observed that both drugs were able to reduce cell viability in a dose-dependent manner and the combined treatment potentiated these effects. Combined treatment also increased cell death and inhibited proliferation of GBM cells, while having no effect on human and rat cultured astrocytes. Also, we observed high protein expression of the catalytic subunit of xc- in all the examined GBM cell lines, and treatment with SAS blocked its activity and decreased intracellular GSH levels. Noteworthy, SAS but not VPA was also able to reduce the [14C]-ascorbate uptake. Together, these data indicate that SAS and VPA exhibit a substantial effect on GBM cell's death related to an intracellular oxidative response imbalance, making this combination of drugs a promising therapeutic strategy.
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16
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Homocysteine Induces Glial Reactivity in Adult Rat Astrocyte Cultures. Mol Neurobiol 2017; 55:1966-1976. [PMID: 28255907 DOI: 10.1007/s12035-017-0463-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/16/2017] [Indexed: 02/08/2023]
Abstract
Astrocytes are dynamic glial cells associated to neurotransmitter systems, metabolic functions, antioxidant defense, and inflammatory response, maintaining the brain homeostasis. Elevated concentrations of homocysteine (Hcy) are involved in the pathogenesis of age-related neurodegenerative disorders, such as Parkinson and Alzheimer diseases. In line with this, our hypothesis was that Hcy could promote glial reactivity in a model of cortical primary astrocyte cultures from adult Wistar rats. Thus, cortical astrocytes were incubated with different concentrations of Hcy (10, 30, and 100 μM) during 24 h. After the treatment, we analyzed cell viability, morphological parameters, antioxidant defenses, and inflammatory response. Hcy did not induce any alteration in cell viability; however, it was able to induce cytoskeleton rearrangement. The treatment with Hcy also promoted a significant decrease in the activities of Na+, K+ ATPase, superoxide dismutase (SOD), and glutathione peroxidase (GPx), as well as in the glutathione (GSH) content. Additionally, Hcy induced an increase in the pro-inflammatory cytokine release. In an attempt to elucidate the putative mechanisms involved in the Hcy-induced glial reactivity, we measured the nuclear factor kappa B (NFκB) transcriptional activity and heme oxygenase 1 (HO-1) expression, which were activated and inhibited by Hcy, respectively. In summary, our findings provide important evidences that Hcy modulates critical astrocyte parameters from adult rats, which might be associated to the aging process.
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17
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Li Y, Cao LL, Liu L, Qi QD. Serum levels of homocysteine at admission are associated with post-stroke depression in acute ischemic stroke. Neurol Sci 2017; 38:811-817. [DOI: 10.1007/s10072-017-2848-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/08/2017] [Indexed: 01/19/2023]
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18
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Effect of Hyperhomocysteinemia on Redox Balance and Redox Defence Enzymes in Ischemia-Reperfusion Injury and/or After Ischemic Preconditioning in Rats. Cell Mol Neurobiol 2017; 37:1417-1431. [PMID: 28210876 DOI: 10.1007/s10571-017-0473-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 02/12/2017] [Indexed: 12/21/2022]
Abstract
Increased level of homocysteine (hHcy) in plasma is an accompanying phenomenon of many diseases, including a brain stroke. This study determines whether hyperhomocysteinemia (which is a risk factor of brain ischemia) itself or in combination with ischemic preconditioning affects the ischemia-induced neurodegenerative changes, generation of reactive oxygen species (ROS), lipoperoxidation, protein oxidation, and activity of antioxidant enzymes in the rat brain cortex. The hHcy was induced by subcutaneous administration of homocysteine (0.45 μmol/g body weight) twice a day in 8 h intervals for 14 days. Rats were preconditioned by 5 min ischemia. Two days later, 15 min of global forebrain ischemia was induced by four vessel's occlusion. The study demonstrates that in the cerebral cortex, hHcy alone induces progressive neuronal cell death and morphological changes. Neuronal damage was associated with the pro-oxidative effect of hHcy, which leads to increased ROS formation, peroxidation of lipids and oxidative alterations of cortical proteins. Ischemic reperfusion injury activates degeneration processes and de-regulates redox balance which is aggravated under hHcy conditions and leads to the augmented lipoperoxidation and protein oxidation. If combined with hHcy, ischemic preconditioning could preserve the neuronal tissue from lethal ischemic effect and initiates suppression of lipoperoxidation, protein oxidation, and alterations of redox enzymes with the most significant effect observed after prolonged reperfusion. Increased prevalence of hyperhomocysteinemia in the Western population and crucial role of elevated Hcy level in the pathogenesis of neuronal disorders makes this amino acid as an interesting target for future research. Understanding the multiple etiological mechanisms and recognition of the co-morbid risk factors that lead to the ischemic/reperfusion injury and ischemic tolerance is therefore important for developing therapeutic strategies in human brain stroke associated with the elevated level of Hcy.
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Heimfarth L, da Silva Ferreira F, Pierozan P, Mingori MR, Moreira JCF, da Rocha JBT, Pessoa-Pureur R. Astrocyte-neuron interaction in diphenyl ditelluride toxicity directed to the cytoskeleton. Toxicology 2017; 379:1-11. [PMID: 28137618 DOI: 10.1016/j.tox.2017.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/05/2017] [Accepted: 01/23/2017] [Indexed: 01/04/2023]
Abstract
Diphenylditelluride (PhTe)2 is a neurotoxin that disrupts cytoskeletal homeostasis. We are showing that different concentrations of (PhTe)2 caused hypophosphorylation of glial fibrillary acidic protein (GFAP), vimentin and neurofilament subunits (NFL, NFM and NFH) and altered actin organization in co-cultured astrocytes and neurons from cerebral cortex of rats. These mechanisms were mediated by N-methyl-d-aspartate (NMDA) receptors without participation of either L-type voltage-dependent calcium channels (L-VDCC) or metabotropic glutamate receptors. Upregulated Ca2+ influx downstream of NMDA receptors activated Ca2+-dependent protein phosphatase 2B (PP2B) causing hypophosphorylation of astrocyte and neuron IFs. Immunocytochemistry showed that hypophosphorylated intermediate filaments (IF) failed to disrupt their organization into the cytoskeleton. However, phalloidin-actin-FITC stained cytoskeleton evidenced misregulation of actin distribution, cell spreading and increased stress fibers in astrocytes. βIII tubulin staining showed that neurite meshworks are not altered by (PhTe)2, suggesting greater susceptibility of astrocytes than neurons to (PheTe)2 toxicity. These findings indicate that signals leading to IF hypophosphorylation fail to disrupt the cytoskeletal IF meshwork of interacting astrocytes and neurons in vitro however astrocyte actin network seems more susceptible. Our findings support that intracellular Ca2+ is one of the crucial signals that modulate the action of (PhTe)2 in co-cultured astrocytes and neurons and highlights the cytoskeleton as an end-point of the neurotoxicity of this compound. Cytoskeletal misregulation is associated with cell dysfunction, therefore, the understanding of the molecular mechanisms mediating the neurotoxicity of this compound is a matter of increasing interest since tellurium compounds are increasingly released in the environment.
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Affiliation(s)
- Luana Heimfarth
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | | | - Paula Pierozan
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | - Moara Rodrigues Mingori
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil
| | | | | | - Regina Pessoa-Pureur
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil.
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20
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Lehotský J, Tothová B, Kovalská M, Dobrota D, Beňová A, Kalenská D, Kaplán P. Role of Homocysteine in the Ischemic Stroke and Development of Ischemic Tolerance. Front Neurosci 2016; 10:538. [PMID: 27932944 PMCID: PMC5120102 DOI: 10.3389/fnins.2016.00538] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/03/2016] [Indexed: 01/17/2023] Open
Abstract
Homocysteine (Hcy) is a toxic, sulfur-containing intermediate of methionine metabolism. Hyperhomocysteinemia (hHcy), as a consequence of impaired Hcy metabolism or defects in crucial co-factors that participate in its recycling, is assumed as an independent human stroke risk factor. Neural cells are sensitive to prolonged hHcy treatment, because Hcy cannot be metabolized either by the transsulfuration pathway or by the folate/vitamin B12 independent remethylation pathway. Its detrimental effect after ischemia-induced damage includes accumulation of reactive oxygen species (ROS) and posttranslational modifications of proteins via homocysteinylation and thiolation. Ischemic preconditioning (IPC) is an adaptive response of the CNS to sub-lethal ischemia, which elevates tissues tolerance to subsequent ischemia. The main focus of this review is on the recent data on homocysteine metabolism and mechanisms of its neurotoxicity. In this context, the review documents an increased oxidative stress and functional modification of enzymes involved in redox balance in experimentally induced hyperhomocysteinemia. It also gives an interpretation whether hyperhomocysteinemia alone or in combination with IPC affects the ischemia-induced neurodegenerative changes as well as intracellular signaling. Studies document that hHcy alone significantly increased Fluoro-Jade C- and TUNEL-positive cell neurodegeneration in the rat hippocampus as well as in the cortex. IPC, even if combined with hHcy, could still preserve the neuronal tissue from the lethal ischemic effects. This review also describes the changes in the mitogen-activated protein kinase (MAPK) protein pathways following ischemic injury and IPC. These studies provide evidence for the interplay and tight integration between ERK and p38 MAPK signaling mechanisms in response to the hHcy and also in association of hHcy with ischemia/IPC challenge in the rat brain. Further investigations of the protective factors leading to ischemic tolerance and recognition of the co-morbid risk factors would result in development of new avenues for exploration of novel therapeutics against ischemia and stroke.
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Affiliation(s)
- Ján Lehotský
- Institute of Medical Biochemistry and BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava Martin, Slovakia
| | - Barbara Tothová
- Institute of Medical Biochemistry and BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava Martin, Slovakia
| | - Maria Kovalská
- Institute of Medical Biochemistry and BioMed, Jessenius Faculty of Medicine, Comenius University in BratislavaMartin, Slovakia; Institute of Histology and Embryology, Jessenius Faculty of Medicine, Comenius University in BratislavaMartin, Slovakia
| | - Dušan Dobrota
- Institute of Medical Biochemistry and BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava Martin, Slovakia
| | - Anna Beňová
- Institute of Medical Biochemistry and BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava Martin, Slovakia
| | - Dagmar Kalenská
- Institute of Medical Biochemistry and BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava Martin, Slovakia
| | - Peter Kaplán
- Institute of Medical Biochemistry and BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava Martin, Slovakia
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21
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Kim S, Nho K, Ramanan VK, Lai D, Foroud TM, Lane K, Murrell JR, Gao S, Hall KS, Unverzagt FW, Baiyewu O, Ogunniyi A, Gureje O, Kling MA, Doraiswamy PM, Kaddurah-Daouk R, Hendrie HC, Saykin AJ. Genetic Influences on Plasma Homocysteine Levels in African Americans and Yoruba Nigerians. J Alzheimers Dis 2016; 49:991-1003. [PMID: 26519441 DOI: 10.3233/jad-150651] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Plasma homocysteine, a metabolite involved in key cellular methylation processes seems to be implicated in cognitive functions and cardiovascular health with its high levels representing a potential modifiable risk factor for Alzheimer's disease (AD) and other dementias. A better understanding of the genetic factors regulating homocysteine levels, particularly in non-white populations, may help in risk stratification analyses of existing clinical trials and may point to novel targets for homocysteine-lowering therapy. To identify genetic influences on plasma homocysteine levels in individuals with African ancestry, we performed a targeted gene and pathway-based analysis using a priori biological information and then to identify new association performed a genome-wide association study. All analyses used combined data from the African American and Yoruba cohorts from the Indianapolis-Ibadan Dementia Project. Targeted analyses demonstrated significant associations of homocysteine and variants within the CBS (Cystathionine beta-Synthase) gene. We identified a novel genome-wide significant association of the AD risk gene CD2AP (CD2-associated protein) with plasma homocysteine levels in both cohorts. Minor allele (T) carriers of identified CD2AP variant (rs6940729) exhibited decreased homocysteine level. Pathway enrichment analysis identified several interesting pathways including the GABA receptor activation pathway. This is noteworthy given the known antagonistic effect of homocysteine on GABA receptors. These findings identify several new targets warranting further investigation in relation to the role of homocysteine in neurodegeneration.
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Affiliation(s)
- Sungeun Kim
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana University Network Science Institute, Bloomington, IN, USA
| | - Kwangsik Nho
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana University Network Science Institute, Bloomington, IN, USA
| | - Vijay K Ramanan
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Internal Medicine, Preliminary Medicine Residency, St. Vincent Indianapolis, Indianapolis, IN, USA
| | - Dongbing Lai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tatiana M Foroud
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana University Network Science Institute, Bloomington, IN, USA.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Katie Lane
- Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jill R Murrell
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sujuan Gao
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kathleen S Hall
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Frederick W Unverzagt
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Olusegun Baiyewu
- Department of Psychiatry, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Adesola Ogunniyi
- Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Oye Gureje
- Department of Psychiatry, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Mitchel A Kling
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Behavioral Health Service, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - P Murali Doraiswamy
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA.,Duke Institute for Brain Sciences, Duke University, Durham, NC, USA
| | - Rima Kaddurah-Daouk
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA.,Duke Institute for Brain Sciences, Duke University, Durham, NC, USA.,Pharmacometabolomics Center, Duke University, Durham, NC, USA
| | - Hugh C Hendrie
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana University Center for Aging Research, Indianapolis, IN, USA.,Regenstrief Institute Inc., Indianapolis, IN, USA
| | - Andrew J Saykin
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA.,Indiana University Network Science Institute, Bloomington, IN, USA.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
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22
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Pierozan P, Biasibetti H, Schmitz F, Ávila H, Fernandes CG, Pessoa-Pureur R, Wyse ATS. Neurotoxicity of Methylmercury in Isolated Astrocytes and Neurons: the Cytoskeleton as a Main Target. Mol Neurobiol 2016; 54:5752-5767. [DOI: 10.1007/s12035-016-0101-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/05/2016] [Indexed: 01/16/2023]
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23
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Calcium signaling mechanisms disrupt the cytoskeleton of primary astrocytes and neurons exposed to diphenylditelluride. Biochim Biophys Acta Gen Subj 2016; 1860:2510-2520. [PMID: 27475002 DOI: 10.1016/j.bbagen.2016.07.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/20/2016] [Accepted: 07/25/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND Diphenylditelluride (PhTe)2 is a potent neurotoxin disrupting the homeostasis of the cytoskeleton. METHODS Cultured astrocytes and neurons were incubated with (PhTe)2, receptor antagonists and enzyme inhibitors followed by measurement of the incorporation of [32P]orthophosphate into intermediate filaments (IFs). RESULTS (PhTe)2 caused hyperphosphorylation of glial fibrillary acidic protein (GFAP), vimentin and neurofilament subunits (NFL, NFM and NFH) from primary astrocytes and neurons, respectively. These mechanisms were mediated by N-methyl-d-aspartate (NMDA) receptors, L-type voltage-dependent calcium channels (L-VDCCs) as well as metabotropic glutamate receptors upstream of phospholipase C (PLC). Upregulated Ca(2+) influx activated protein kinase A (PKA) and protein kinase C (PKC) in astrocytes causing hyperphosphorylation of GFAP and vimentin. Hyperphosphorylated (IF) together with RhoA-activated stress fiber formation, disrupted the cytoskeleton leading to altered cell morphology. In neurons, the high intracellular Ca(2+) levels activated the MAPKs, Erk and p38MAPK, beyond PKA and PKC, provoking hyperphosphorylation of NFM, NFH and NFL. CONCLUSIONS Our findings support that intracellular Ca(2+) is one of the crucial signals that modulate the action of (PhTe)2 in isolated cortical astrocytes and neurons modulating the response of the cytoskeleton against the insult. GENERAL SIGNIFICANCE Cytoskeletal misregulation is associated with neurodegeneration. This compound could be a valuable tool to induce molecular changes similar to those found in different pathologies of the brain.
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Acute Hyperammonemia Induces NMDA-Mediated Hypophosphorylation of Intermediate Filaments Through PP1 and PP2B in Cerebral Cortex of Young Rats. Neurotox Res 2016; 30:138-49. [PMID: 26936604 DOI: 10.1007/s12640-016-9607-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/20/2016] [Accepted: 02/10/2016] [Indexed: 11/27/2022]
Abstract
In the present work, we studied the effects of toxic ammonia levels on the cytoskeleton of neural cells, with emphasis in the homeostasis of the phosphorylating system associated with the intermediate filaments (IFs). We used in vivo and in vitro models of acute hyperammonemia in 10- and 21-day-old rats. In the in vivo model, animals were intraperitoneally injected with ammonium acetate (7 mmol/Kg), and the phosphorylation level of the cytoskeletal proteins was analyzed in the cerebral cortex and hippocampus 30 and 60 min after injection. The injected ammonia altered the IF phosphorylation of astrocytes (GFAP and vimentin) and neurons (neurofilament subunits of low, middle, and high molecular weight, respectively: NFL, NFM, and NFH) from cerebral cortex of 21-day-old rats. This was a transitory effect observed 30 min after injection, recovering 30 min afterward. Phosphorylation was not altered in the cerebral cortex of 10-day-old pups. The homeostasis of hippocampal IFs was preserved at the studied ages and times. In the in vitro model, cortical slices of 10- and 21-day-old rats were incubated with 0.5, 1, or 5 mM NH4Cl, and the phosphorylation level of the IF proteins was analyzed after 30 min. The IF phosphorylation was not altered in cortical slices of 10-day-old rats; however, in cortical slices of 21-day-old pups, 5 mM NH4Cl induced hypophosphorylation of GFAP and vimentin, preserving neurofilament phosphorylation levels. Hypophosphorylation was mediated by the protein phosphatases 1 (PP1) and 2B (PP2B), and this event was associated with Ca(2+) influx via N-methyl-D-aspartate (NMDA) glutamate receptors. The aim of this study is to show that acute ammonia toxicity targets the phosphorylating system of IFs in the cerebral cortex of rats in a developmentally regulated manner, and NMDA-mediated Ca(2+) signaling plays a central role in this mechanism. We propose that the disruption of cytoskeletal homeostasis could be an endpoint of the acute hyperammonemia in the developing brain. We believe that these results contribute for better understanding the molecular basis of the ammonia toxicity in brain.
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ŠKOVIEROVÁ H, MAHMOOD S, BLAHOVCOVÁ E, HATOK J, LEHOTSKÝ J, MURÍN R. Effect of Homocysteine on Survival of Human Glial Cells. Physiol Res 2015; 64:747-54. [DOI: 10.33549/physiolres.932897] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Several neurodegenerative conditions, such as Alzheimer’s disease and Parkinson’s disease, or vascular dementia and cognitive impairment, are associated with mild hyperhomocysteinemia. Hyperhomocysteinemia is defined as an increase of the homocysteine (Hcy) level beyond 10 μM. Although the adverse effect of Hcy on neurons is well documented, knowledge about the impact of this amino acid on glial cells is missing. Therefore, with the aim to evaluate the neurotoxic properties of Hcy on glial cells, we used a glioblastoma cell line as a study model. The viability of cells was assayed biochemically and cytologically. At a concentration around 50 μM in the culture medium D,L-Hcy induced cell death. It is noteworthy that Hcy induces cell death of human glial cells at concentrations encountered during mild hyperhomocysteinemia. Therefore, we propose that Hcy-induced impairment of neuronal functions along with damage of glial cells may contribute to the etiopathogenesis of neurodegenerative diseases associated with hyperhomocysteinemia.
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Affiliation(s)
| | | | | | | | | | - R. MURÍN
- Department of Medical Biochemistry, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
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Abushik PA, Karelina TV, Sibarov DA, Stepanenko YD, Giniatullin RA, Antonov SM. Homocysteine-induced membrane currents, calcium responses and changes in mitochondrial potential in rat cortical neurons. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093015040055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Bukharaeva E, Shakirzyanova A, Khuzakhmetova V, Sitdikova G, Giniatullin R. Homocysteine aggravates ROS-induced depression of transmitter release from motor nerve terminals: potential mechanism of peripheral impairment in motor neuron diseases associated with hyperhomocysteinemia. Front Cell Neurosci 2015; 9:391. [PMID: 26500495 PMCID: PMC4594498 DOI: 10.3389/fncel.2015.00391] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/18/2015] [Indexed: 12/13/2022] Open
Abstract
Homocysteine (HCY) is a pro-inflammatory sulphur-containing redox active endogenous amino acid, which concentration increases in neurodegenerative disorders including amyotrophic lateral sclerosis (ALS). A widely held view suggests that HCY could contribute to neurodegeneration via promotion of oxidative stress. However, the action of HCY on motor nerve terminals has not been investigated so far. We previously reported that oxidative stress inhibited synaptic transmission at the neuromuscular junction, targeting primarily the motor nerve terminals. In the current study, we investigated the effect of HCY on oxidative stress-induced impairment of transmitter release at the mouse diaphragm muscle. The mild oxidant H2O2 decreased the intensity of spontaneous quantum release from nerve terminals (measured as the frequency of miniature endplate potentials, MEPPs) without changes in the amplitude of MEPPs, indicating a presynaptic effect. Pre-treatment with HCY for 2 h only slightly affected both amplitude and frequency of MEPPs but increased the inhibitory potency of H2O2 almost two fold. As HCY can activate certain subtypes of glutamate N-methyl D-aspartate (NMDA) receptors we tested the role of NMDA receptors in the sensitizing action of HCY. Remarkably, the selective blocker of NMDA receptors, AP-5 completely removed the sensitizing effect of HCY on the H2O2-induced presynaptic depressant effect. Thus, at the mammalian neuromuscular junction HCY largely increases the inhibitory effect of oxidative stress on transmitter release, via NMDA receptors activation. This combined effect of HCY and local oxidative stress can specifically contribute to the damage of presynaptic terminals in neurodegenerative motoneuron diseases, including ALS.
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Affiliation(s)
- Ellya Bukharaeva
- Department of Physiology, Kazan Federal UniversityKazan, Russia
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern FinlandKuopio, Finland
- Kazan Institute of Biochemistry and BiophysicsKazan, Russia
| | - Anastasia Shakirzyanova
- Department of Physiology, Kazan Federal UniversityKazan, Russia
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern FinlandKuopio, Finland
| | - Venera Khuzakhmetova
- Department of Physiology, Kazan Federal UniversityKazan, Russia
- Kazan Institute of Biochemistry and BiophysicsKazan, Russia
| | - Guzel Sitdikova
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern FinlandKuopio, Finland
| | - Rashid Giniatullin
- Department of Physiology, Kazan Federal UniversityKazan, Russia
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern FinlandKuopio, Finland
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NMDA Receptors and Oxidative Stress Induced by the Major Metabolites Accumulating in HMG Lyase Deficiency Mediate Hypophosphorylation of Cytoskeletal Proteins in Brain From Adolescent Rats: Potential Mechanisms Contributing to the Neuropathology of This Disease. Neurotox Res 2015; 28:239-52. [PMID: 26174040 DOI: 10.1007/s12640-015-9542-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/01/2015] [Accepted: 07/07/2015] [Indexed: 01/01/2023]
Abstract
Neurological symptoms and cerebral abnormalities are commonly observed in patients with 3-hydroxy-3-methylglutaryl-CoA lyase (HMG lyase) deficiency, which is biochemically characterized by predominant tissue accumulation of 3-hydroxy-3-methylglutaric (HMG), 3-methylglutaric (MGA), and 3-methylglutaconic (MGT) acids. Since the pathogenesis of this disease is poorly known, the present study evaluated the effects of these compounds on the cytoskeleton phosphorylating system in rat brain. HMG, MGA, and MGT caused hypophosphorylation of glial fibrillary acidic protein (GFAP) and of the neurofilament subunits NFL, NFM, and NFH. HMG-induced hypophosphorylation was mediated by inhibiting the cAMP-dependent protein kinase (PKA) on Ser55 residue of NFL and c-Jun kinase (JNK) by acting on KSP repeats of NFM and NFH subunits. We also evidenced that the subunit NR2B of NMDA receptor and Ca(2+) was involved in HMG-elicited hypophosphorylation of cytoskeletal proteins. Furthermore, the antioxidants L-NAME and TROLOX fully prevented both the hypophosphorylation and the inhibition of PKA and JNK caused by HMG, suggesting that oxidative damage may underlie these effects. These findings indicate that the main metabolites accumulating in HMG lyase deficiency provoke hypophosphorylation of cytoskeleton neural proteins with the involvement of NMDA receptors, Ca(2+), and reactive species. It is presumed that these alterations may contribute to the neuropathology of this disease.
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Han Y, Xi Q, Dai W, Yang S, Gao L, Su Y, Zhang X. Abnormal transsulfuration metabolism and reduced antioxidant capacity in Chinese children with autism spectrum disorders. Int J Dev Neurosci 2015; 46:27-32. [DOI: 10.1016/j.ijdevneu.2015.06.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/20/2015] [Accepted: 06/29/2015] [Indexed: 11/29/2022] Open
Affiliation(s)
- Yu Han
- School of Public HealthTianjin Medical UniversityTianjinChina
| | - Qian‐qian Xi
- School of Public HealthTianjin Medical UniversityTianjinChina
| | - Wei Dai
- School of Public HealthTianjin Medical UniversityTianjinChina
| | - Shu‐han Yang
- School of Public HealthTianjin Medical UniversityTianjinChina
| | - Lei Gao
- School of Public HealthTianjin Medical UniversityTianjinChina
| | - Yuan‐yuan Su
- School of Public HealthTianjin Medical UniversityTianjinChina
| | - Xin Zhang
- School of Public HealthTianjin Medical UniversityTianjinChina
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30
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Nuñez-Figueredo Y, Pardo Andreu GL, Oliveira Loureiro S, Ganzella M, Ramírez-Sánchez J, Ochoa-Rodríguez E, Verdecia-Reyes Y, Delgado-Hernández R, Souza DO. The effects of JM-20 on the glutamatergic system in synaptic vesicles, synaptosomes and neural cells cultured from rat brain. Neurochem Int 2015; 81:41-7. [DOI: 10.1016/j.neuint.2015.01.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/24/2014] [Accepted: 01/15/2015] [Indexed: 01/07/2023]
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Crosstalk Among Disrupted Glutamatergic and Cholinergic Homeostasis and Inflammatory Response in Mechanisms Elicited by Proline in Astrocytes. Mol Neurobiol 2015; 53:1065-1079. [PMID: 25579384 DOI: 10.1007/s12035-014-9067-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 12/29/2014] [Indexed: 12/12/2022]
Abstract
Hyperprolinemias are inherited disorder of proline (Pro) metabolism. Patients affected may present neurological manifestations, but the mechanisms of neural excitotoxicity elicited by hyperprolinemia are far from being understood. Considering that the astrocytes are important players in neurological disorders, the aim of the present work was to study the effects 1 mM Pro on glutamatergic and inflammatory parameters in cultured astrocytes from cerebral cortex of rats, exploring some molecular mechanisms underlying the disrupted homeostasis of astrocytes exposed to this toxic Pro concentration. We showed that cortical astrocytes of rats exposed to 1 mM Pro presented significantly elevated extracellular glutamate and glutamine levels, suggesting glutamate excitotoxicity. The excess of glutamate elicited by Pro together with increased glutamate uptake and upregulated glutamine synthetase (GS) activity supported misregulated glutamate homeostasis in astrocytic cells. High Pro levels also induced production/release of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. We also evidenced misregulation of cholinergic anti-inflammatory system with increased acetylcholinesterase (AChE) activity and decreased acetylcholine (ACh) levels, contributing to the inflammatory status in Pro-treated astrocytes. Our findings highlighted a crosstalk among disrupted glutamate homeostasis, cholinergic mechanisms, and inflammatory cytokines, since ionotropic (DL-AP5 and CNQX) and metabotropic (MCPG and MPEP) glutamate antagonists were able to restore the extracellular glutamate and glutamine levels; downregulate TNFα and IL6 production/release, modulate GS and AChE activities; and restore ACh levels. Otherwise, the non-steroidal anti-inflammatory drugs nimesulide, acetylsalicylic acid, ibuprofen, and diclofenac sodium decreased the extracellular glutamate and glutamine levels, downregulated GS and AChE activities, and restored ACh levels in Pro-treated astrocytes. Altogether, our results evidence that the vulnerability of metabolic homeostasis in cortical astrocytes might have important implications in the neurotoxicity of Pro.
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Ampadu J, Morley JE. Heart failure and cognitive dysfunction. Int J Cardiol 2015; 178:12-23. [DOI: 10.1016/j.ijcard.2014.10.087] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 10/20/2014] [Indexed: 10/24/2022]
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Pierozan P, Ferreira F, de Lima BO, Pessoa-Pureur R. Quinolinic acid induces disrupts cytoskeletal homeostasis in striatal neurons. Protective role of astrocyte-neuron interaction. J Neurosci Res 2014; 93:268-84. [DOI: 10.1002/jnr.23494] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/29/2014] [Accepted: 09/14/2014] [Indexed: 12/18/2022]
Affiliation(s)
- Paula Pierozan
- Departamento de Bioquímica; Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul; Porto Alegre Brazil
| | - Fernanda Ferreira
- Departamento de Bioquímica; Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul; Porto Alegre Brazil
| | - Bárbara Ortiz de Lima
- Departamento de Bioquímica; Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul; Porto Alegre Brazil
| | - Regina Pessoa-Pureur
- Departamento de Bioquímica; Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul; Porto Alegre Brazil
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Moustafa AA, Hewedi DH, Eissa AM, Frydecka D, Misiak B. Homocysteine levels in schizophrenia and affective disorders-focus on cognition. Front Behav Neurosci 2014; 8:343. [PMID: 25339876 PMCID: PMC4186289 DOI: 10.3389/fnbeh.2014.00343] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/11/2014] [Indexed: 01/05/2023] Open
Abstract
Although homocysteine (Hcy) has been widely implicated in the etiology of various physical health impairments, especially cardiovascular diseases, overwhelming evidence indicates that Hcy is also involved in the pathophysiology of schizophrenia and affective disorders. There are several mechanisms linking Hcy to biological underpinnings of psychiatric disorders. It has been found that Hcy interacts with NMDA receptors, initiates oxidative stress, induces apoptosis, triggers mitochondrial dysfunction and leads to vascular damage. Elevated Hcy levels might also contribute to cognitive impairment that is widely observed among patients with affective disorders and schizophrenia. Supplementation of vitamins B and folic acid has been proved to be effective in lowering Hcy levels. There are also studies showing that this supplementation strategy might be beneficial for schizophrenia patients with respect to alleviating negative symptoms. However, there are no studies addressing the influence of add-on therapies with folate and vitamins B on cognitive performance of patients with schizophrenia and affective disorders. In this article, we provide an overview of Hcy metabolism in psychiatric disorders focusing on cognitive correlates and indicating future directions and perspectives.
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Affiliation(s)
- Ahmed A Moustafa
- School of Social Sciences and Psychology and Marcs Institute for Brain and Behaviour, University of Western Sydney Sydney, NSW, Australia
| | - Doaa H Hewedi
- Psychogeriatric Research Center, Department of Psychiatry, School of Medicine, Ain Shams University Cairo, Egypt
| | - Abeer M Eissa
- Psychogeriatric Research Center, Department of Psychiatry, School of Medicine, Ain Shams University Cairo, Egypt
| | - Dorota Frydecka
- Department and Clinic of Psychiatry, Wroclaw Medical University Wroclaw, Poland
| | - Błażej Misiak
- Department and Clinic of Psychiatry, Wroclaw Medical University Wroclaw, Poland ; Department of Genetics, Wroclaw Medical University Wroclaw, Poland
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35
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Pierozan P, Gonçalves Fernandes C, Ferreira F, Pessoa-Pureur R. Acute intrastriatal injection of quinolinic acid provokes long-lasting misregulation of the cytoskeleton in the striatum, cerebral cortex and hippocampus of young rats. Brain Res 2014; 1577:1-10. [DOI: 10.1016/j.brainres.2014.06.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/16/2014] [Accepted: 06/19/2014] [Indexed: 10/25/2022]
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36
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Signaling mechanisms and disrupted cytoskeleton in the diphenyl ditelluride neurotoxicity. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:458601. [PMID: 25050142 PMCID: PMC4090446 DOI: 10.1155/2014/458601] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 02/26/2014] [Indexed: 01/14/2023]
Abstract
Evidence from our group supports that diphenyl ditelluride (PhTe)2 neurotoxicity depends on modulation of signaling pathways initiated at the plasma membrane. The (PhTe)2-evoked signal is transduced downstream of voltage-dependent Ca2+ channels (VDCC), N-methyl-D-aspartate receptors (NMDA), or metabotropic glutamate receptors activation via different kinase pathways (protein kinase A, phospholipase C/protein kinase C, mitogen-activated protein kinases (MAPKs), and Akt signaling pathway). Among the most relevant cues of misregulated signaling mechanisms evoked by (PhTe)2 is the cytoskeleton of neural cells. The in vivo and in vitro exposure to (PhTe)2 induce hyperphosphorylation/hypophosphorylation of neuronal and glial intermediate filament (IF) proteins (neurofilaments and glial fibrillary acidic protein, resp.) in different brain structures of young rats. Phosphorylation of IFs at specific sites modulates their association/disassociation and interferes with important physiological roles, such as axonal transport. Disrupted cytoskeleton is a crucial marker of neurodegeneration and is associated with reactive astrogliosis and apoptotic cell death. This review focuses the current knowledge and important results on the mechanisms of (PhTe)2 neurotoxicity with special emphasis on the cytoskeletal proteins and their differential regulation by kinases/phosphatases and Ca2+-mediated mechanisms in developmental rat brain. We propose that the disrupted cytoskeletal homeostasis could support brain damage provoked by this neurotoxicant.
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37
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Tu WJ, Yin CH, Guo YQ, Li SO, Chen H, Zhang Y, Feng YL, Long BH. Serum homocysteine concentrations in Chinese children with autism. Clin Chem Lab Med 2014; 51:e19-22. [PMID: 23095201 DOI: 10.1515/cclm-2012-0196] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 07/08/2012] [Indexed: 11/15/2022]
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38
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Ferreira GD, Germeyer A, de Barros Machado A, do Nascimento TL, Strowitzki T, Brum IS, von Eye Corleta H, Capp E. Metformin modulates PI3K and GLUT4 expression and Akt/PKB phosphorylation in human endometrial stromal cells after stimulation with androgen and insulin. Eur J Obstet Gynecol Reprod Biol 2014; 175:157-62. [DOI: 10.1016/j.ejogrb.2014.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 12/17/2013] [Accepted: 01/04/2014] [Indexed: 11/27/2022]
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39
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Pierozan P, Ferreira F, Ortiz de Lima B, Gonçalves Fernandes C, Totarelli Monteforte P, de Castro Medaglia N, Bincoletto C, Soubhi Smaili S, Pessoa-Pureur R. The phosphorylation status and cytoskeletal remodeling of striatal astrocytes treated with quinolinic acid. Exp Cell Res 2014; 322:313-23. [PMID: 24583400 DOI: 10.1016/j.yexcr.2014.02.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/10/2014] [Accepted: 02/19/2014] [Indexed: 12/24/2022]
Abstract
Quinolinic acid (QUIN) is a glutamate agonist which markedly enhances the vulnerability of neural cells to excitotoxicity. QUIN is produced from the amino acid tryptophan through the kynurenine pathway (KP). Dysregulation of this pathway is associated with neurodegenerative conditions. In this study we treated striatal astrocytes in culture with QUIN and assayed the endogenous phosphorylating system associated with glial fibrillary acidic protein (GFAP) and vimentin as well as cytoskeletal remodeling. After 24h incubation with 100 µM QUIN, cells were exposed to (32)P-orthophosphate and/or protein kinase A (PKA), protein kinase dependent of Ca(2+)/calmodulin II (PKCaMII) or protein kinase C (PKC) inhibitors, H89 (20 μM), KN93 (10 μM) and staurosporin (10nM), respectively. Results showed that hyperphosphorylation was abrogated by PKA and PKC inhibitors but not by the PKCaMII inhibitor. The specific antagonists to ionotropic NMDA and non-NMDA (50 µM DL-AP5 and CNQX, respectively) glutamate receptors as well as to metabotropic glutamate receptor (mGLUR; 50 µM MCPG), mGLUR1 (100 µM MPEP) and mGLUR5 (10 µM 4C3HPG) prevented the hyperphosphorylation provoked by QUIN. Also, intra and extracellular Ca(2+) quelators (1mM EGTA; 10 µM BAPTA-AM, respectively) prevented QUIN-mediated effect, while Ca(2+) influx through voltage-dependent Ca(2+) channel type L (L-VDCC) (blocker: 10 µM verapamil) is not implicated in this effect. Morphological analysis showed dramatically altered actin cytoskeleton with concomitant change of morphology to fusiform and/or flattened cells with retracted cytoplasm and disruption of the GFAP meshwork, supporting misregulation of actin cytoskeleton. Both hyperphosphorylation and cytoskeletal remodeling were reversed 24h after QUIN removal. Astrocytes are highly plastic cells and the vulnerability of astrocyte cytoskeleton may have important implications for understanding the neurotoxicity of QUIN in neurodegenerative disorders.
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Affiliation(s)
- Paula Pierozan
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90035-003, Brazil
| | - Fernanda Ferreira
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90035-003, Brazil
| | - Bárbara Ortiz de Lima
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90035-003, Brazil
| | - Carolina Gonçalves Fernandes
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90035-003, Brazil
| | | | | | - Claudia Bincoletto
- Departamento de Farmacologia, Universidade Federal de São Paulo (UNIFESP/EPM), São Paulo, SP, Brazil
| | - Soraya Soubhi Smaili
- Departamento de Farmacologia, Universidade Federal de São Paulo (UNIFESP/EPM), São Paulo, SP, Brazil
| | - Regina Pessoa-Pureur
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 90035-003, Brazil.
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Abushik PA, Niittykoski M, Giniatullina R, Shakirzyanova A, Bart G, Fayuk D, Sibarov DA, Antonov SM, Giniatullin R. The role of NMDA and mGluR5 receptors in calcium mobilization and neurotoxicity of homocysteine in trigeminal and cortical neurons and glial cells. J Neurochem 2013; 129:264-74. [DOI: 10.1111/jnc.12615] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 11/19/2013] [Accepted: 11/19/2013] [Indexed: 02/06/2023]
Affiliation(s)
- Polina A. Abushik
- Department of Neurobiology; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
- Laboratory of Comparative Physiology of Cerebellum; Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Science; Saint-Petersburg Russia
| | - Minna Niittykoski
- Department of Neurobiology; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
- Biotechnology and Molecular Medicine; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
| | - Raisa Giniatullina
- Department of Neurobiology; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
| | - Anastasia Shakirzyanova
- Department of Neurobiology; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
| | - Genevieve Bart
- Department of Neurobiology; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
| | - Dmitriy Fayuk
- Department of Neurobiology; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
| | - Dmitry A. Sibarov
- Laboratory of Comparative Physiology of Cerebellum; Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Science; Saint-Petersburg Russia
- Laboratory of Molecular Neurodegeneration; Saint-Petersburg State Polytechnic University; Saint-Petersburg Russia
| | - Sergei M. Antonov
- Laboratory of Comparative Physiology of Cerebellum; Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Science; Saint-Petersburg Russia
- Laboratory of Molecular Neurodegeneration; Saint-Petersburg State Polytechnic University; Saint-Petersburg Russia
| | - Rashid Giniatullin
- Department of Neurobiology; A. I. Virtanen Institute for Molecular Sciences; University of Eastern Finland; Kuopio Finland
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41
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An L, Li Z, Zhang T. Reversible effects of vitamins C and E combination on oxidative stress-induced apoptosis in melamine-treated PC12 cells. Free Radic Res 2013; 48:239-50. [PMID: 24182201 DOI: 10.3109/10715762.2013.861598] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Due to its high nitrogen content, melamine was deliberately added to raw milk for increasing the apparent protein content. Previous studies showed that melamine-induced apoptosis and oxidative damage on PC12 cells and rats' hippocampus. Several evidences suggested that vitamin antioxidant reduced oxidative stress and improved organic function. Whether treatments with antioxidant vitamins C or E, otherwise combination of them can attenuate oxidative stress after melamine administration remains to be elucidated. In this study, the reversible effects of vitamin antioxidants was investigated on melamine-induced neurotoxicity in cultured PC12 cells, an in vitro model of neuronal cells. When comparing vitamin C and E, the combination of both statistically increased PC12 cells viability. The results further showed that vitamin complex has effectively reduced the formation of reaction oxygen species, decreased the level of malondialdehyde, and elevated the activities of antioxidative enzymes. Hoechst 33342 staining and flow cytometric analysis of apoptosis showed that vitamin combination treatment effectively prevented PC12 cells from this melamine-induced apoptosis. It revealed the apoptotic nuclear features of the melamine-induced cell death. Additionally, a combination treatment of vitamins effectively inhibited apoptosis via blocking the increased activation of caspase-3. In summary, the vitamin E and C combination treatment could rescue PC12 cells from the injury induced by melamine through the downregulation of oxidative stress and prevention of melamine-induced apoptosis.
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Affiliation(s)
- L An
- College of Life Sciences and Key Laboratory of Bioactive Materials Ministry of Education, Nankai University , Tianjin , P. R. China
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Loureiro SO, Heimfarth L, Scherer EB, da Cunha MJ, de Lima BO, Biasibetti H, Pessoa-Pureur R, Wyse AT. Cytoskeleton of cortical astrocytes as a target to proline through oxidative stress mechanisms. Exp Cell Res 2013; 319:89-104. [DOI: 10.1016/j.yexcr.2012.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 10/09/2012] [Accepted: 11/01/2012] [Indexed: 11/28/2022]
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Homocysteine induced SH-SY5Y apoptosis through activation of NADPH oxidase in U251MG cells. Neurosci Res 2011; 72:9-15. [PMID: 22001762 DOI: 10.1016/j.neures.2011.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/14/2011] [Accepted: 09/29/2011] [Indexed: 11/23/2022]
Abstract
Epidemiological studies have indicated a correlation between homocysteinemia and dementia, including Alzheimer's disease. However, the mechanism by which homocysteine (Hcy) induces neuronal cell death remains unknown. We found that micromolar concentrations of Hcy induced neuroblastoma SH-SY5Y cell death only when co-cultured with glioblastoma U251MG cells. In this culture system, cysteine had no effect on SH-SY5Y cell death. There was an increase in TUNEL-positive cells and loss of mitochondrial membrane potential following treatment with 100 μM Hcy. Addition of conditioned medium prepared from U251MG cells in the presence of 100 μM Hcy also reduced SH-SY5Y cell viability, while this effect was prevented when using conditioned medium from U251MG cells exposed to 100 μM Hcy+apocynin, a specific NADPH oxidase inhibitor. Following exposure to 100 μM Hcy in U251MG cells, expression of Rac1, a compartment of NADPH oxidase, was translocated to the plasma membrane, and the active form of Rac1 was increased. There was no change in peroxide concentration in the medium of U251MG cells after addition of Hcy. Overall, these data suggest that Hcy stimulates Rac1 activation and NADPH oxidase, resulting in superoxide anion production that may induce SH-SY5Y cell apoptosis.
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Ganapathy PS, White RE, Ha Y, Bozard BR, McNeil PL, Caldwell RW, Kumar S, Black SM, Smith SB. The role of N-methyl-D-aspartate receptor activation in homocysteine-induced death of retinal ganglion cells. Invest Ophthalmol Vis Sci 2011; 52:5515-24. [PMID: 21436276 DOI: 10.1167/iovs.10-6870] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Elevated plasma homocysteine has been implicated in glaucoma, a vision disorder characterized by retinal ganglion cell death. The toxic potential of homocysteine to ganglion cells is known, but the mechanisms are not clear. A mechanism of homocysteine-induced death of cerebral neurons is via N-methyl-D-aspartate (NMDA) receptor overstimulation, leading to excess calcium influx and oxidative stress. This study examined the role of the NMDA receptor in homocysteine-mediated ganglion cell death. METHODS Primary mouse ganglion cells were used for these experiments. NMDA receptor stimulation by homocysteine was determined by patch clamp analysis and fluorescent detection of intracellular calcium. NMDA receptor involvement in homocysteine-mediated cell death was determined through assessment of lactate dehydrogenase release and TUNEL analysis. These experiments used the NMDA receptor blocker MK-801. Induction of reactive species superoxide, nitric oxide, and peroxynitrite was measured by electron paramagnetic resonance spectroscopy, chemiluminescent nitric oxide detection, and immunoblotting for nitrotyrosine, respectively. RESULTS 50 μM homocysteine stimulated the NMDA receptor in presence of 100 μM glycine. Homocysteine induced 59.67 ± 4.89% ganglion cell death that was reduced to 19.87 ± 3.03% with cotreatment of 250 nM MK-801. Homocysteine elevated intracellular calcium ∼7-fold, which was completely prevented by MK-801. Homocysteine treatment increased superoxide and nitric oxide levels by ∼40% and ∼90%, respectively, after 6 hours. Homocysteine treatment elevated peroxynitrite by ∼85% after 9 hours. CONCLUSIONS These experiments provide compelling evidence that homocysteine induces retinal ganglion cell toxicity through direct NMDA receptor stimulation and implicate, for the first time, the induction of oxidative stress as a potent mechanism of homocysteine-mediated ganglion cell death.
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Affiliation(s)
- Preethi S Ganapathy
- Department of Cellular Biology and Anatomy, Georgia Health Sciences, University, Medical College of Georgia, Augusta, GA, USA
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Jin Y, Amaral A, McCann A, Brennan L. Homocysteine levels impact directly on epigenetic reprogramming in astrocytes. Neurochem Int 2011; 58:833-8. [PMID: 21419186 DOI: 10.1016/j.neuint.2011.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 03/08/2011] [Accepted: 03/09/2011] [Indexed: 11/16/2022]
Abstract
Although the neurotoxic effects of homocysteine have been well elucidated, the effects of homocysteine in astrocytes have received little attention until recently. Previously we have demonstrated that elevated levels of homocysteine caused significant metabolic changes and altered mitochondrial function in primary cultures of astrocytes. However, the mechanisms behind such alterations remain unclear. As homocysteine is a key metabolite in one-carbon metabolism the present study examined if the effects of homocysteine on astrocyte function are mediated through an epigenetic mechanism. Following exposure to homocysteine for 72 h, global DNA methylation and H3K9 acetylation were examined using flow cytometric analysis. Total DNA methyltransferase activity and protein levels of DNA methyltransferase 3B were measured. Exposure to homocysteine resulted in global DNA hypomethylation (p<0.05) and histone hyperacetylation (p<0.05). Total DNA methyltransferase activity significantly decreased following exposure to homocysteine (from 11.5 ± 3.9 to 6.0 ± 1.7OD/h/mg protein, p<0.01) which was accompanied by a significant reduction in protein levels of DNA methyltransferase 3B (p<0.05). Treatment of astrocytes with the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine, mimicked the functional changes induced by homocysteine. In conclusion, the results demonstrate significant epigenetic modifications following exposure to homocysteine in astrocytes and these changes seem to mediate functional alterations.
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Affiliation(s)
- Ying Jin
- UCD School of Agriculture, Food Science and Veterinary Medicine, Dublin 4, Ireland
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Hemendinger RA, Armstrong EJ, Brooks BR. Methyl Vitamin B12 but not methylfolate rescues a motor neuron-like cell line from homocysteine-mediated cell death. Toxicol Appl Pharmacol 2011; 251:217-25. [PMID: 21237187 DOI: 10.1016/j.taap.2011.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 01/01/2011] [Accepted: 01/05/2011] [Indexed: 12/13/2022]
Abstract
Homocysteine is an excitatory amino acid implicated in multiple diseases including amyotrophic lateral sclerosis (ALS). Information on the toxicity of homocysteine in motor neurons is limited and few studies have examined how this toxicity can be modulated. In NSC-34D cells (a hybrid cell line derived from motor neuron-neuroblastoma), homocysteine induces apoptotic cell death in the millimolar range with a TC₅₀ (toxic concentration at which 50% of maximal cell death is achieved) of 2.2 mM, confirmed by activation of caspase 3/7. Induction of apoptosis was independent of short-term reactive oxygen species (ROS) generation. Methyl Vitamin B12 (MeCbl) and methyl tetrahydrofolate (MTHF), used clinically to treat elevated homocysteine levels, were tested for their ability to reverse homocysteine-mediated motor neuron cell death. MeCbl in the micromolar range was able to provide neuroprotection (2 h pretreatment prior to homocysteine) and neurorescue (simultaneous exposure with homocysteine) against millimolar homocysteine with an IC₅₀ (concentration at which 50% of maximal cell death is inhibited) of 0.6 μM and 0.4 μM, respectively. In contrast, MTHF (up to 10 μM) had no effect on homocysteine-mediated cell death. MeCbl inhibited caspase 3/7 activation by homocysteine in a time- and dose-dependent manner, whereas MTHF had no effect. We conclude that MeCbl is effective against homocysteine-induced cell death in motor neurons in a ROS-independent manner, via a reduction in caspase activation and apoptosis. MeCbl decreases Hcy induced motor neuron death in vitro in a hybrid cell line derived from motor neuron-neuroblastoma and may play a role in the treatment of late stage ALS where HCy levels are increased in animal models of ALS.
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Affiliation(s)
- Richelle A Hemendinger
- Motor Neuron Cell Biology Group, Department of Neurology, Carolinas Neuromuscular/ALS-MDA Center, Carolinas Medical Center, Charlotte, NC 28203, USA.
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Kang YJ. Copper and homocysteine in cardiovascular diseases. Pharmacol Ther 2010; 129:321-31. [PMID: 21130114 DOI: 10.1016/j.pharmthera.2010.11.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 11/08/2010] [Indexed: 02/05/2023]
Abstract
High blood copper (Cu) and homocysteine (Hcy) concentrations have been independently reported as risk factors for cardiovascular diseases. When they are simultaneously measured, a concomitant increase in both parameters in association with vascular dysfunction has been observed. Cu chelator penicillamine can significantly diminish the inhibitory effect of Hcy on endothelial function, which has led to the interpretation that Cu mediates the deleterious effect of Hcy. However, Cu itself has been shown to be beneficial to the cardiovascular system. In particular, Cu promotion of angiogenesis has been well documented. Cu stimulates endothelial cell proliferation and differentiation and promotes microtubule formation in cultured saphenous veins. High levels of Hcy do not affect the process of microtubule formation, but the combination of Cu and Hcy leads to a significant inhibitory effect. Under other conditions, Cu does not affect, but Hcy inhibits, the endothelium-dependent relaxation of blood vessels and the combination of both augments the inhibition. Why does Cu produce adverse effects when it co-exists with Hcy? Cu forms complexes with Hcy and the Cu-Hcy complexes possess a deleterious potential due to their redox properties. Cu chelation can remove Cu from the Cu-Hcy complexes, but leaves behind high levels of Hcy and produces Cu deficiency. An alternative approach should focus on the reduction of Hcy, but maintenance of Cu, making detrimental Cu beneficial. A comprehensive understanding of Cu speciation and a development of selective modulation of Cu coordination to Cu-binding molecules to avoid Cu-Hcy complex formation would effectively improve the condition of cardiovascular disease.
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Affiliation(s)
- Y James Kang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China.
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