Browsing by Subject "Ferritin"

Now showing 1 - 6 of 6
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    Abnormal iron homeostasis and neurodegeneration
    (Frontiers Media, 2013-07-30) Muhoberac, Barry B.; Vidal, Ruben; Chemistry and Chemical Biology, School of Science
    Abnormal iron metabolism is observed in many neurodegenerative diseases, however, only two have shown dysregulation of brain iron homeostasis as the primary cause of neurodegeneration. Herein, we review one of these - hereditary ferritinopathy (HF) or neuroferritinopathy, which is an autosomal dominant, adult onset degenerative disease caused by mutations in the ferritin light chain (FTL) gene. HF has a clinical phenotype characterized by a progressive movement disorder, behavioral disturbances, and cognitive impairment. The main pathologic findings are cystic cavitation of the basal ganglia, the presence of ferritin inclusion bodies (IBs), and substantial iron deposition. Mutant FTL subunits have altered sequence and length but assemble into soluble 24-mers that are ultrastructurally indistinguishable from those of the wild type. Crystallography shows substantial localized disruption of the normally tiny 4-fold pores between the ferritin subunits because of unraveling of the C-termini into multiple polypeptide conformations. This structural alteration causes attenuated net iron incorporation leading to cellular iron mishandling, ferritin aggregation, and oxidative damage at physiological concentrations of iron and ascorbate. A transgenic murine model parallels several features of HF, including a progressive neurological phenotype, ferritin IB formation, and misregulation of iron metabolism. These studies provide a working hypothesis for the pathogenesis of HF by implicating (1) a loss of normal ferritin function that triggers iron accumulation and overproduction of ferritin polypeptides, and (2) a gain of toxic function through radical production, ferritin aggregation, and oxidative stress. Importantly, the finding that ferritin aggregation can be reversed by iron chelators and oxidative damage can be inhibited by radical trapping may be used for clinical investigation. This work provides new insights into the role of abnormal iron metabolism in neurodegeneration.
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    Abnormal iron metabolism in fibroblasts from a patient with the neurodegenerative disease hereditary ferritinopathy
    (BMC, 2010-11-10) Barbeito, Ana G.; Levade, Thierry; Delisle, Marie B.; Ghetti, Bernardino; Vidal, Ruben; Pathology and Laboratory Medicine, School of Medicine
    Background Nucleotide duplications in exon 4 of the ferritin light polypeptide (FTL) gene cause the autosomal dominant neurodegenerative disease neuroferritinopathy or hereditary ferritinopathy (HF). Pathologic examination of patients with HF has shown abnormal ferritin and iron accumulation in neurons and glia in the central nervous system (CNS) as well as in cells of other organ systems, including skin fibroblasts. To gain some understanding on the molecular basis of HF, we characterized iron metabolism in primary cultures of human skin fibroblasts from an individual with the FTL c.497_498dupTC mutation. Results Compared to normal controls, HF fibroblasts showed abnormal iron metabolism consisting of increased levels of ferritin polypeptides, divalent metal transporter 1, basal iron content and reactive oxygen species, and decreased levels of transferrin receptor-1 and IRE-IRP binding activity. Conclusions Our data indicates that HF fibroblasts replicate the abnormal iron metabolism observed in the CNS of patients with HF. We propose that HF fibroblasts are a unique cellular model in which to study the role of abnormal iron metabolism in the pathogenesis of HF without artifacts derived from over-expression or lack of endogenous translational regulatory elements.
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    Iron deficiency reduces synapse formation in the Drosophila clock circuit
    (Humana Press, 2019-05) Rudisill, Samuel S.; Martin, Bradley R.; Mankowski, Kevin M.; Tessier, Charles R.; Medical and Molecular Genetics, School of Medicine
    Iron serves as a critical cofactor for proteins involved in a host of biological processes. In most animals, dietary iron is absorbed in enterocytes and then disseminated for use in other tissues in the body. The brain is particularly dependent on iron. Altered iron status correlates with disorders ranging from cognitive dysfunction to disruptions in circadian activity. The exact role iron plays in producing these neurological defects, however, remains unclear. Invertebrates provide an attractive model to study the effects of iron on neuronal development since many of the genes involved in iron metabolism are conserved, and the organisms are amenable to genetic and cytological techniques. We have examined synapse growth specifically under conditions of iron deficiency in the Drosophila circadian clock circuit. We show that projections of the small ventrolateral clock neurons to the protocerebrum of the adult Drosophila brain are significantly reduced upon chelation of iron from the diet. This growth defect persists even when iron is restored to the diet. Genetic neuronal knockdown of ferritin 1 or ferritin 2, critical components of iron storage and transport, does not affect synapse growth in these cells. Together, these data indicate that dietary iron is necessary for central brain synapse formation in the fly and further validate the use of this model to study the function of iron homeostasis on brain development.
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    Neonatal Graves Disease Masquerading as Hemochromatosis
    (Oxford University Press, 2024-07-24) Maggiotto, Liesbeth; Mittelman, Steven D.; Fallah, Roja; Pediatrics, School of Medicine
    Thyroid autoimmunity is extremely common in the adult population and can affect pregnancy outcomes. Signs in the newborn can range from absent to severe, making the diagnosis easy to miss. We present an interesting case of neonatal Graves disease associated with intrauterine growth restriction, premature delivery, and liver failure with severely high ferritin, thought to be secondary to hemochromatosis. Treatment of the underlying hyperthyroidism caused a rapid resolution of the elevated ferritin and liver failure. This report highlights the importance of considering Graves disease in newborns with liver failure of unknown etiology.
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    Neuroprotective Strategies and Cell-Based Biomarkers for Manganese-Induced Toxicity in Human Neuroblastoma (SH-SY5Y) Cells
    (MDPI, 2024-05-31) Cahill, Catherine M.; Sarang, Sanjan S.; Bakshi, Rachit; Xia, Ning; Lahiri, Debomoy K.; Rogers, Jack T.; Psychiatry, School of Medicine
    Manganese (Mn) is an essential heavy metal in the human body, while excess Mn leads to neurotoxicity, as observed in this study, where 100 µM of Mn was administered to the human neuroblastoma (SH-SY5Y) cell model of dopaminergic neurons in neurodegenerative diseases. We quantitated pathway and gene changes in homeostatic cell-based adaptations to Mn exposure. Utilizing the Gene Expression Omnibus, we accessed the GSE70845 dataset as a microarray of SH-SY5Y cells published by Gandhi et al. (2018) and applied statistical significance cutoffs at p < 0.05. We report 74 pathway and 10 gene changes with statistical significance. ReactomeGSA analyses demonstrated upregulation of histones (5 out of 10 induced genes) and histone deacetylases as a neuroprotective response to remodel/mitigate Mn-induced DNA/chromatin damage. Neurodegenerative-associated pathway changes occurred. NF-κB signaled protective responses via Sirtuin-1 to reduce neuroinflammation. Critically, Mn activated three pathways implicating deficits in purine metabolism. Therefore, we validated that urate, a purine and antioxidant, mitigated Mn-losses of viability in SH-SY5Y cells. We discuss Mn as a hypoxia mimetic and trans-activator of HIF-1α, the central trans-activator of vascular hypoxic mitochondrial dysfunction. Mn induced a 3-fold increase in mRNA levels for antioxidant metallothionein-III, which was induced 100-fold by hypoxia mimetics deferoxamine and zinc.
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    Serum Hepcidin Levels Are Associated With Obesity but Not Liver Disease
    (Wiley, 2014) Vuppalanchi, Raj; Troutt, Jason S.; Konrad, Robert J.; Ghabril, Marwan; Saxena, Romil; Bell, Lauren N.; Kowdley, Kris V.; Chalasani, Naga; Medicine, School of Medicine
    Objective: Hepcidin is regulated by anemia and inflammation. It is primarily expressed in the liver but studies have reported its expression in adipose tissue. The relationship between BMI and serum hepcidin and the relationship between liver histology and serum hepcidin in the morbidly obese was investigated. Methods: Serum and liver tissue from patients undergoing bariatric surgery (bariatric cohort, n = 105) and serum from healthy blood donors (n = 60) were used to conduct this study. Serum hepcidin was measured using sandwich ELISA, highly specific for hepcidin-25. Serum ferritin, IL-6, IL-1β and liver function biochemistries were also measured. Results: After controlling for covariates, BMI ≥ 35 kg/m(2) was significantly associated with higher serum hepcidin level compared to individuals with lower BMI groups (17.7 ± 11.5 vs. 3.3 ± 4.7 ng/ml, P = 0.002). The presence of NAFLD was not associated with higher serum levels of hepcidin (multivariate P = 0.37). There was no association between serum hepcidin levels and liver histology (presence of steatohepatitis, advanced fibrosis, or NAFLD activity score) in the bariatric cohort. Conclusions: Obesity, but not the presence of NAFLD was associated with serum hepcidin levels. There was no association between serum hepcidin and liver histology in the morbidly obese undergoing bariatric surgery.