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Heidari M, Johnstone DM, Bassett B, Graham RM, Chua ACG, House MJ, Collingwood JF, Bettencourt C, Houlden H, Ryten M, Olynyk JK, Trinder D, Milward EA. Brain iron accumulation affects myelin-related molecular systems implicated in a rare neurogenetic disease family with neuropsychiatric features. Mol Psychiatry 2016; 21:1599-1607. [PMID: 26728570 PMCID: PMC5078858 DOI: 10.1038/mp.2015.192] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 10/01/2015] [Accepted: 10/26/2015] [Indexed: 11/25/2022]
Abstract
The 'neurodegeneration with brain iron accumulation' (NBIA) disease family entails movement or cognitive impairment, often with psychiatric features. To understand how iron loading affects the brain, we studied mice with disruption of two iron regulatory genes, hemochromatosis (Hfe) and transferrin receptor 2 (Tfr2). Inductively coupled plasma atomic emission spectroscopy demonstrated increased iron in the Hfe-/- × Tfr2mut brain (P=0.002, n ≥5/group), primarily localized by Perls' staining to myelinated structures. Western immunoblotting showed increases of the iron storage protein ferritin light polypeptide and microarray and real-time reverse transcription-PCR revealed decreased transcript levels (P<0.04, n ≥5/group) for five other NBIA genes, phospholipase A2 group VI, fatty acid 2-hydroxylase, ceruloplasmin, chromosome 19 open reading frame 12 and ATPase type 13A2. Apart from the ferroxidase ceruloplasmin, all are involved in myelin homeostasis; 16 other myelin-related genes also showed reduced expression (P<0.05), although gross myelin structure and integrity appear unaffected (P>0.05). Overlap (P<0.0001) of differentially expressed genes in Hfe-/- × Tfr2mut brain with human gene co-expression networks suggests iron loading influences expression of NBIA-related and myelin-related genes co-expressed in normal human basal ganglia. There was overlap (P<0.0001) of genes differentially expressed in Hfe-/- × Tfr2mut brain and post-mortem NBIA basal ganglia. Hfe-/- × Tfr2mut mice were hyperactive (P<0.0112) without apparent cognitive impairment by IntelliCage testing (P>0.05). These results implicate myelin-related systems involved in NBIA neuropathogenesis in early responses to iron loading. This may contribute to behavioral symptoms in NBIA and hemochromatosis and is relevant to patients with abnormal iron status and psychiatric disorders involving myelin abnormalities or resistant to conventional treatments.
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Affiliation(s)
- M Heidari
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
| | - D M Johnstone
- Bosch Institute and Discipline of Physiology, University of Sydney, Sydney, NSW, Australia
| | - B Bassett
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia
| | - R M Graham
- School of Biomedical Sciences and Curtin Health Innovation Research Institute - Biosciences, Curtin University of Technology, Bentley, WA, Australia
| | - A C G Chua
- School of Medicine and Pharmacology, University of Western Australia, Fiona Stanley Hospital, Murdoch, WA, Australia,Harry Perkins Institute of Medical Research, Murdoch, WA, Australia
| | - M J House
- School of Physics, University of Western Australia, Crawley, WA, Australia
| | - J F Collingwood
- Warwick Engineering in Biomedicine, School of Engineering, University of Warwick, Coventry, UK
| | - C Bettencourt
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK,Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - H Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - M Ryten
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK,Department of Medical and Molecular Genetics, King's College London, London, UK
| | - J K Olynyk
- School of Biomedical Sciences and Curtin Health Innovation Research Institute - Biosciences, Curtin University of Technology, Bentley, WA, Australia,Institute for Immunology and Infectious Diseases, Murdoch University, Perth, WA, Australia,Department of Gastroenterology and Hepatology, Fiona Stanley Hospital, The University of Western Australia, Murdoch, WA, Australia,Department of Gastroenterology and Hepatology, Fremantle Hospital, Fremantle, WA, Australia
| | - D Trinder
- School of Medicine and Pharmacology, University of Western Australia, Fiona Stanley Hospital, Murdoch, WA, Australia,Harry Perkins Institute of Medical Research, Murdoch, WA, Australia
| | - E A Milward
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, Callaghan, NSW, Australia,School of Biomedical Sciences and Pharmacy MSB, University of Newcastle, Callaghan, NSW 2308, Australia. E-mail:
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Abstract
The solubility of 17 beta-oestradiol (E2) in aqueous solutions of polyethylene glycol (PEG) 400 has been measured at 35 degrees C. Up to 80% w/w PEG the solubility data conform to a log linear equation ln S = ln Sw + f sigma where S is the E2 concentration in the water/cosolvent mixture, Sw is E2 solubility in water, f is the weight fraction of PEG 400 and sigma is a parameter representing the solubilizing power of the cosolvent for the drug. Above 80% PEG the relationship becomes less convincing, with significant deviation from anticipated values. Reasons for these aberrations are discussed. It is suggested that conformational changes may be induced in the PEG by the addition of small quantities of water. Deviations noted for the melting point, viscosity and density data of PEG 400-water solutions may also confirm this suggestion.
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Bassett B, Goodman RN, Novacky A. Ultrastructure of soybean nodules. II: deterioration of the symbiosis in ineffective nodules. Can J Microbiol 1977; 23:873-83. [PMID: 560246 DOI: 10.1139/m77-129] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ineffective nodules, formed on Clark-63 soybeans by Rhizobium japonicum strain 8-0 (Iowa), and effective nodules, formed on Clark-63 soybeans by strain 138 (U.S.D.A.), have been examined by electron microscopy at 10–12, 16, and 21 days after seed inoculation. Though strain 8-0 bacteria are able to infect the host cells in a normal manner, infection is followed closely by a progressive deterioration of the symbiosis involving selective autolysis of host cell contents and degeneration of the intracellular bacteria. The host cells, though disrupted, apparently survive the destruction of the bacteria. The observed ultrastructural changes suggest either a suddenly manifested incompatibility between host and rhizobia, or an acute, localized, nitrogen starvation in the infected cells.
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Abstract
Root nodules on soybeans (var. Clark 63) were examined by transmission electron microscopy 10-12 days after seed inoculation and planting. The cell infection process appeared identical in both effective nodules, induced by Rhizobium japonicum strain 138 (USDA) and in ineffective nodules, induced by strain 8-0 (Iowa). Electron micrographs are presented which suggest that rhizobia are freed from the infection thread by disintegration of the thread wall and compartmentalization of the distintegrated wall material in membrane-bound vesicles derived from the membrane surrounding the thread. As the thread wall is removed in this manner, the bacteria are released into the host cytoplasm by a process which encloses each in an envelope also dervide from the thread membrane. Any thread wall material remaining around a bacterium after it has dissociated from the thread is removed from the envelope space by vesiculation of the membrane envelope. thus, it appears that endocytosis of both the bacteria and the material composing the infection thread wall occurs during release of rhizobia into the host cell.
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