Cuprizone Administration Alters the Iron Metabolism in the Mouse Model of Multiple Sclerosis (original) (raw)

Relationship of Iron Metabolism and Short-Term Cuprizone Treatment of C57BL/6 Mice

International Journal of Molecular Sciences

One of the models to investigate the distinct mechanisms contributing to neurodegeneration in multiple sclerosis is based on cuprizone (CZ) intoxication. CZ is toxic to mature oligodendrocytes and produces demyelination within the central nervous system but does not cause direct neuronal damage. The CZ model is suitable for better understanding the molecular mechanism of de- and remyelination processes of oligodendrocytes. CZ is a copper chelating agent and it also affects the iron metabolism in brain and liver tissues. To determine the early effect of CZ treatment on iron homeostasis regulation, cytosolic and mitochondrial iron storage, as well as some lipid metabolism genes, we investigated the expression of respective iron homeostasis and lipid metabolism genes of the corpus callosum (CC) and the liver after short-term CZ administration. In the present study C57BL/6 male mice aged four weeks were fed with standard rodent food premixed with 0.2 w/w% CZ for two or eight days. The m...

Ferroptosis Mediates Cuprizone-Induced Loss of Oligodendrocytes and Demyelination

The Journal of Neuroscience

Multiple sclerosis (MS) is a chronic demyelinating disease of the CNS. Cuprizone (CZ), a copper chelator, is widely used to study demyelination and remyelination in the CNS, in the context of MS. However, the mechanisms underlying oligodendrocyte (OL) cell loss and demyelination are not known. As copper-containing enzymes play important roles in iron homeostasis and controlling oxidative stress, we examined whether chelating copper leads to disruption of molecules involved in iron homeostasis that can trigger iron-mediated OL loss. We show that giving mice (male) CZ in the diet induces rapid loss of OL in the corpus callosum by 2 d, accompanied by expression of several markers for ferroptosis, a relatively newly described form of iron-mediated cell death. In ferroptosis, iron-mediated free radicals trigger lipid peroxidation under conditions of glutathione insufficiency, and a reduced capacity to repair lipid damage. This was further confirmed using a small-molecule inhibitor of ferroptosis that prevents CZ-induced loss of OL and demyelination, providing clear evidence of a copper-iron connection in CZ-induced neurotoxicity. This work has wider implications for disorders, such as multiple sclerosis and CNS injury.

The Role of Iron and Copper in the Aetiology of Neurodegenerative Disorders

CNS Drugs, 2002

Abnormalities in the metabolism of the transition metals iron and copper have been demonstrated to play a crucial role in the pathogenesis of various neurodegenerative diseases. Metal homeostasis as it pertains to alterations in brain function in neurodegenerative diseases is reviewed in this article in depth. While there is documented evidence for alterations in the homeostasis, redox-activity and localisation of transition metals, it is also important to realise that alterations in specific copper-and iron-containing metalloenzymes appear to play a crucial role in the neurodegenerative process. These changes provide the opportunity to identify pathways where modification of the disease process can occur, potentially offering opportunities for clinical intervention. As understanding of disease aetiology evolves, so do the tools with which diseases are treated. In this article, we examine not only the possible mechanism of disease but also how pharmaceuticals may intervene, from direct and indirect antioxidant therapy to strategies involving gene therapy.

Iron and neurodegeneration in the multiple sclerosis brain

Annals of Neurology, 2013

Objective: Iron may contribute to the pathogenesis and progression of multiple sclerosis (MS) due to its accumulation in the human brain with age. Our study focused on nonheme iron distribution and the expression of the ironrelated proteins ferritin, hephaestin, and ceruloplasmin in relation to oxidative damage in the brain tissue of 33 MS and 30 control cases. Methods: We performed (1) whole-genome microarrays including 4 MS and 3 control cases to analyze the expression of iron-related genes, (2) nonheme iron histochemistry, (3) immunohistochemistry for proteins of iron metabolism, and (4) quantitative analysis by digital densitometry and cell counting in regions representing different stages of lesion maturation. Results: We found an age-related increase of iron in the white matter of controls as well as in patients with short disease duration. In chronic MS, however, there was a significant decrease of iron in the normal-appearing white matter (NAWM) corresponding with disease duration, when corrected for age. This decrease of iron in oligodendrocytes and myelin was associated with an upregulation of iron-exporting ferroxidases. In active MS lesions, iron was apparently released from dying oligodendrocytes, resulting in extracellular accumulation of iron and uptake into microglia and macrophages. Iron-containing microglia showed signs of cell degeneration. At lesion edges and within centers of lesions, iron accumulated in astrocytes and axons. Interpretation: Iron decreases in the NAWM of MS patients with increasing disease duration. Cellular degeneration in MS lesions leads to waves of iron liberation, which may propagate neurodegeneration together with inflammatory oxidative burst.

Pathogenic implications of iron accumulation in multiple sclerosis

Journal of Neurochemistry, 2012

Iron, an essential element used for a multitude of biochemical reactions, abnormally accumulates in the central nervous system of patients with multiple sclerosis (MS). The mechanisms of abnormal iron deposition in MS are not fully understood, nor do we know whether these deposits have adverse consequences, i.e., contribute to pathogenesis. With some exceptions, excess levels of iron are represented concomitantly in multiple deep gray matter structures often with bilateral representation, while in white matter pathological iron deposits are usually located at sites of inflammation that are associated with veins. These distinct spatial patterns suggest disparate mechanisms of iron accumulation between these regions. Iron has been postulated to promote disease activity in MS by various means: 1) iron can amplify the activated state of microglia resulting in the increased production of proinflammatory mediators; 2) excess intracellular iron deposits could promote mitochondria dysfunction; and 3) improperly managed iron could catalyze the production of damaging reactive oxygen species. The pathological consequences of abnormal iron deposits may be dependent on the affected brain region and/or accumulation process. Here we review putative mechanisms of enhanced iron uptake in MS and address the likely roles of iron in the pathogenesis of this disease.

Iron and Mechanisms of Neurotoxicity

International Journal of Alzheimer's Disease, 2011

The accumulation of transition metals (e.g., copper, zinc, and iron) and the dysregulation of their metabolism are a hallmark in the pathogenesis of several neurodegenerative diseases. This paper will be focused on the mechanism of neurotoxicity mediated by iron. This metal progressively accumulates in the brain both during normal aging and neurodegenerative processes. High iron concentrations in the brain have been consistently observed in Alzheimer's (AD) and Parkinson's (PD) diseases. In this connection, metalloneurobiology has become extremely important in establishing the role of iron in the onset and progression of neurodegenerative diseases. Neurons have developed several protective mechanisms against oxidative stress, among them, the activation of cellular signaling pathways. The final response will depend on the identity, intensity, and persistence of the oxidative insult. The characterization of the mechanisms mediating the effects of iron-induced increase in neuronal dysfunction and death is central to understanding the pathology of a number of neurodegenerative disorders.

Role of Iron and Copper in the Pathogenesis of Parkinson’s Disease

Indian Journal of Clinical Biochemistry, 2016

Parkinson's disease (PD) is an old age disorder of basal ganglia which involves oligomerization of asynuclein protein and formation of intercellular inclusions known as ''Lewy bodies'' in substantia nigra and caudate nuclei in brain which is progressive in nature. It is second most prevalent neurodegenerative disorder characterized by tremor at rest, muscle rigidity, slowness of movement (bradykinesia, akinesia), and changes in posture (instability). Both excess and deficiency in levels of transition metals (especially iron, copper) can be detrimental to the central nervous system. Abnormalities in iron (Fe) and copper (Cu) metabolism have been reported to produce oxidative stress which is one of the major cause in pathogenesis of PD. In the present study 35 PD patients and 33 controls of Northern Indian population were included and serum levels of Fe, Cu and ceruloplasmin (Cp) were measured. Serum Fe (p \ 0.01) and Cu (p \ 0.01) levels were found to be significantly decreased in PD, whereas there was no significant change in Cp levels in PD patients as compared to controls. These results suggest the existence of a defect in iron which over the time, may hasten the entry of iron into the brain and decrease iron in the extracellular compartment in PD patients.

Iron and neurodegeneration: From cellular homeostasis to disease

Oxidative Medicine and Cellular Longevity, 2012

Accumulation of iron (Fe) is often detected in the brains of people suffering from neurodegenerative diseases. High Fe concentrations have been consistently observed in Parkinson's, Alzheimer's, and Huntington's diseases; however, it is not clear whether this Fe contributes to the progression of these diseases. Other conditions, such as Friedreich's ataxia or neuroferritinopathy are associated with genetic factors that cause Fe misregulation. Consequently, excessive intracellular Fe increases oxidative stress, which leads to neuronal dysfunction and death. The characterization of the mechanisms involved in the misregulation of Fe in the brain is crucial to understand the pathology of the neurodegenerative disorders and develop new therapeutic strategies. Saccharomyces cerevisiae, as the best understood eukaryotic organism, has already begun to play a role in the neurological disorders; thus it could perhaps become a valuable tool also to study the metalloneurobiology.

Brain oxidative stress in rat with chronic iron or copper overload

Journal of Inorganic Biochemistry, 2019

Male rats of 80-90 g that were fed 42 days with a commercial rodent diet of 2780 kcal/100 g and received chronic overloads of either Fe(II) or Cu(II) in the drinking water. The two metals produced brain oxidative stress and damage with marked increases in the indicators of oxidative processes: in vivo brain surface chemiluminescence (the sensitive organ non-invasive assay for oxidative free radical reactions), and the ex vivo processes of phospholipid peroxidation and protein oxidation. Brain redox imbalance was also indicated by marked decreases in the cellular indicators of oxidative metabolic stress: reduced glutathione (GSH) content and reduced/oxidized glutathione ratio (GSH/GSSG). Brain decreased GSH content has a central role in the biochemical oxidative processes associated with Fe and Cu chronic damage. The understanding of biochemical oxidative imbalances in the rat brain with chronic Fe(II) or Cu(II) overloads may be useful for the establishment of pharmacological therapies for human pathologies associated to Fe and Cu cellular imbalances.