lactoferrin and Neurodegenerative-Diseases

It is over 60years since the discovery and isolation of the serum ferroxidase ceruloplasmin. In that time much basic information about the protein has been elucidated including its catalytic and kinetic properties as an enzyme, expression, sequence and structure. The importance of its biological role is indicated in genetic diseases such as aceruloplasminemia where its function is lost through mutation. Despite this wealth of data, fundamental questions about its action remain unanswered and in this article we address the question of how ferric iron produced by the ferroxidase activity of ceruloplasmin could be taken up by transferrins or lactoferrins.. Overlapping peptide libraries for human ceruloplasmin have been probed with a number of different lactoferrins to identify putative lactoferrin-binding regions on human ceruloplasmin. Docking software, 3D-Garden, has been used to model the binding of human lactoferrin to human ceruloplasmin.. Upon probing the human ceruloplasmin library with human lactoferrin, three predominantly acidic lactoferrin-binding peptides, located in domains 2, 5 and 6 of human ceruloplasmin, were identified. The docking software identified a complex such that the N-lobe of human apo-lactoferrin interacts with the catalytic ferroxidase centre on human ceruloplasmin.. In vitro binding studies and molecular modelling indicate that lactoferrin can bind to ceruloplasmin such that a direct transfer of ferric iron between the two proteins is possible. A direct transfer of ferric iron from ceruloplasmin to lactoferrin would prevent both the formation of potentially toxic hydroxyl radicals and the utilization of iron by pathogenic bacteria.

Topics: Binding Sites; Ceruloplasmin; Humans; Ion Transport; Iron; Iron Metabolism Disorders; Lactoferrin; Models, Molecular; Neurodegenerative Diseases; Protein Binding; Protein Structure, Tertiary; Transferrin

In neurodegenerative diseases such as Alzheimer's and Parkinson's, excessive irons as well as lactoferrin (Lf), but not transferrin (Tf), have been found in and around the affected regions of the brain. These evidences suggest that lactoferrin plays a critical role during neurodegenerative diseases, although Lf-mediated iron transport across blood-brain barrier (BBB) is negligible compared to that of transferrin in normal condition. However, the kinetics of lactoferrins and lactoferrin-mediated iron transport are still unknown.. To determine the kinetic rate constants of lactoferrin-mediated iron transport through BBB, a mass-action based ordinary differential equation model has been presented. A Bayesian framework is developed to estimate the kinetic rate parameters from posterior probability density functions. The iron transport across BBB is studied by considering both Lf- and Tf-mediated pathways for both normal and pathologic conditions.. Using the point estimates of kinetic parameters, our model can effectively reproduce the experimental data of iron transport through BBB endothelial cells. The robustness of the model and parameter estimation process are further verified by perturbation of kinetic parameters. Our results show that surge in high-affinity receptor density increases lactoferrin as well as iron in the brain.. Due to the lack of a feedback loop such as iron regulatory proteins (IRPs) for lactoferrin, iron can transport to the brain continuously, which might increase brain iron to pathological levels and can contribute to neurodegeneration.. This study provides an improved understanding of presence of lactoferrin and iron in the brain during neurodegenerative diseases.

Topics: Bayes Theorem; Biological Transport; Blood-Brain Barrier; Brain; Endothelial Cells; Ion Transport; Iron; Kinetics; Lactoferrin; Models, Theoretical; Neurodegenerative Diseases; Protein Transport; Transferrin

Brain iron accumulation is common in patients with Parkinson's disease (PD). Iron chelators have been investigated for their ability to prevent neurodegenerative diseases with features of iron overload. Given the non-trivial side effects of classical iron chelators, lactoferrin (Lf), a multifunctional iron-binding globular glycoprotein, was screened to identify novel neuroprotective pathways against dopaminergic neuronal impairment. We found that Lf substantially ameliorated PD-like motor dysfunction in the subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. We further showed that Lf could alleviate MPTP-triggered apoptosis of DA neurons, neuroinflammation, and histological alterations. As expected, we also found that Lf suppressed MPTP-induced excessive iron accumulation and the upregulation of divalent metal transporter (DMT1) and transferrin receptor (TFR), which is the main intracellular iron regulation protein, and subsequently improved the activity of several antioxidant enzymes. We probed further and determined that the neuroprotection provided by Lf was involved in the upregulated levels of brain-derived neurotrophic factor (BDNF), hypoxia-inducible factor 1α (HIF-1α) and its downstream protein, accompanied by the activation of extracellular regulated protein kinases (ERK) and cAMP response element binding protein (CREB), as well as decreased phosphorylation of c-Jun N-terminal kinase (JNK) and mitogen activated protein kinase (MAPK)/P38 kinase in vitro and in vivo. Our findings suggest that Lf may be an alternative safe drug in ameliorating MPTP-induced brain abnormalities and movement disorder.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Apoptosis; Behavior, Animal; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Iron; Lactoferrin; Male; MAP Kinase Signaling System; Mice; Motor Disorders; Neurodegenerative Diseases; Neuroglia; Neuroprotective Agents; Reactive Oxygen Species

Oxidative stress associated cell damage is one of the key factors in neurodegeneration development and is highly related to the presence of transition metal ions including iron. Herein, deferasirox, a high affinity iron chelator, was conjugated to lactoferrin molecules by carbodiimide mediated coupling reaction to create a novel drug delivery system with higher brain permeability through receptor mediated transcytosis. Each lactoferrin molecule was averagely attached to 4 to 6 deferasirox molecules resulting in water-soluble conjugated nanostructures which were purified and characterized. Neuroprotective effects of lactoferrin conjugated nanostructures and their cellular uptake were evaluated in differentiated PC12 cell line, and the molecular mechanisms involved in such neuroprotection were elucidated. Lactoferrin conjugates were able to interfere in apoptotic caspase cascade by affecting the expression level of caspase-3, PARP, Bax and Bcl-2. Furthermore, an elevation in the expression level of autophagy markers including Atg7, Atg12-Atg5 and LC3-II/LC3-I ratio was observed. Intraperitoneal injection of lactoferrin conjugates was able to significantly attenuate learning deficits induced by beta amyloid injection in a rat model of Alzheimer's disease, which further confirms a potential neuroprotective effect for lactoferrin conjugated deferasirox in neurodegenerative disorder management through metal chelation therapy.

Topics: Alzheimer Disease; Animals; Apoptosis; Apoptosis Regulatory Proteins; Benzoates; Brain; Carbodiimides; Cell Line, Tumor; Chelating Agents; Chelation Therapy; Deferasirox; Disease Models, Animal; Drug Delivery Systems; Iron; Lactoferrin; Male; Nanostructures; Neurodegenerative Diseases; Neuroprotective Agents; PC12 Cells; Permeability; Rats; Rats, Wistar; Transcytosis; Triazoles