Crossroad between Inflammation, Iron and Lipids in Atherogenesis

Atherosclerosis (ATH) is recognized as a chronic inflammatory condition and it is the leading cause of cardiovascular disease. The process of atherogenesis is characterized by the accumulation and oxidation of LDL (oxLDL) in the vessel wall and subsequent infiltration and activation of immune cells, particularly monocytes in an earlier stage and, later on, lymphocytes. The infiltrated monocytes differentiate into macrophages which then could differentiate into foam cells as a consequence of oxLDL uptake [1]. The recruitment of immune cells to the site of ATH lesion contributes to a local pro-inflammatory state that will promote the development of the atheroma plaque and progression of the disease. However, the exact mechanisms involved in this process are not fully understood. One hypothesis is the contribution of oxidative stress mediated by metals such as iron [2]. Previous authors have shown high iron content in foam cells and also accumulation of hemoglobin and ferritin in the areas rich in foam cells [3]. Herein, we investigate a possible mechanism for cellular iron accumulation by testing the effect of pro-inflammatory as well as pro-atherogenic stimuli in the expression of proteins involved in iron efflux in macrophages.This work was supported by National Institute of Health Doutor Ricardo Jorge, I.P, INSERM (Institut National de la Santé et de la Recherche Médicale), CNRS (Centre National de la Recherche Scientifique), ANR (Agence Nationale de la Recherche, France; ANR- 08- GENO-000) , Fundação para a Ciência e Tecnologia (Grant SFRH/BD/48671/2008) and BioFIG (Center for Biodiversity, Functional and Integrative Genomics)

Long-Term Intranasal Nerve Growth Factor Treatment Favors Neuron Formation in de novo Brain Tissue

ObjectiveTo date, no safe and effective pharmacological treatment has been clinically validated for improving post-stroke neurogenesis. Growth factors are good candidates but low safety has limited their application in the clinic. An additional restraint is the delivery route. Intranasal delivery presents many advantages.Materials and MethodsA brain lesion was induced in twenty-four rats. Nerve growth factor (NGF) 5 μg/kg/day or vehicle was given intranasally from day 10 post-lesion for two periods of five weeks, separated by a two-week wash out period with no treatment. Lesion volume and atrophy were identified by magnetic resonance imaging (MRI). Anxiety and sensorimotor recovery were measured by behavior tests. Neurogenesis, angiogenesis and inflammation were evaluated by histology at 12 weeks.ResultsRemarkable neurogenesis occurred and was visible at the second and third months after the insult. Tissue reconstruction was clearly detected by T2 weighted MRI at 8 and 12 weeks post-lesion and confirmed by histology. In the new tissue (8.1% of the lesion in the NGF group vs. 2.4%, in the control group at 12 weeks), NGF significantly increased the percentage of mature neurons (19% vs. 7%). Angiogenesis and inflammation were not different in the two groups. Sensorimotor recovery was neither improved nor hampered by NGF during the first period of treatment, but NGF treatment limited motor recovery in the second period.InterpretationThe first five-week period of treatment was very well tolerated. This study is the first presenting the effects of a long treatment with NGF and has shown an important tissue regeneration rate at 8 and 12 weeks post-injury. NGF may have increased neuronal differentiation and survival and favored neurogenesis and neuron survival through subventricular zone (SVZ) neurogenesis or reprogramming of reactive astrocytes. For the first time, we evidenced a MRI biomarker of neurogenesis and tissue reconstruction with T2 and diffusion weighted imaging

The effect of pro-inflammatory conditions on iron homeostasis and atherogenesis

This work was supported by National Institute of Health Dr Ricardo Jorge, I.P, INSERM (Institut National de la Santé et de la Recherche Médicale), CNRS (Centre National de la Recherche Scientifique), ANR (Agence Nationale de la Recherche, France; ANR- 08-GENO-000) , Fundação para a Ciência e Tecnologia (Grant SFRH/BD/48671/2008) and BioFIG (B Center for Biodiversity, Functional and Integrative Genomics).Atherosclerosis (ATH) is recognized as a chronic inflammatory condition and it is the leading cause of cardiovascular disease. Atherogenesis is characterized by the accumulation and oxidation of LDL (oxLDL) in the vessel wall and subsequent infiltration, activation of lymphocytes and monocytes, these later ones differentiating into macrophages and subsequently into foam cells. The recruitment of immune cells to the site of lesion contributes to a local pro-inflammatory state that will promote the development of the atheroma plaque and progression of the disease. However, the exact mechanisms involved in this process are not fully understood. One hypothesis is the contribution of oxidative stress mediated by metals such as iron. Previous authors have shown high iron content in foam cells and also accumulation of hemoglobin and ferritin in the areas rich in foam cells. Herein, we investigate a possible pathway for cellular iron accumulation by testing the effect of pro-inflammatory as well as pro-atherogenic stimuli in the expression of proteins involved in iron efflux from macrophages. Mouse bone marrow-derived macrophages (BMDM) were treated with LPS, iron or/and oxLDL. The expression of ferroportin (Fpn, iron exporter), beta-amyloid precursor protein (APP, ferroxidase), ceruloplasmin (Cp, ferroxidase) and hemoxygenase-1 (HO-1, heme catabolism) were analyzed by western blot of subcellular fractions (cytosol, membrane and lipid raft fractions). Oil Red O staining was used to follow foam cell differentiation by oxLDL treatment. APP and HO-1 were shown to be upregulated by both iron and LPS, being recruited to lipid rafts enriched fractions in BMDM. Fpn, present also in lipid rafts, was upregulated by iron and downregulated by LPS confirming our previous observations. Such modulation of proteins involved in iron efflux by inflammatory stimuli could also contribute to disruption of iron metabolism in plaque macrophages. In addition, foam cell differentiation of BMDM by oxLDL was accelerated in the presence of iron. These observations suggest that iron in plaque could be a pro-atherogenic factor. Moreover, effect of oxLDL expression and localization of iron-related proteins on lipid raft microdomains may constitute an important pathway for iron efflux disruption in the plaque environment and is under investigation

Screening for a Canine Model of Choroideremia Exclusively Identifies Nonpathogenic CHM Variants.

International audienceChoroideremia is an X-linked, progressive photoreceptor degeneration disorder due to mutations in CHM. In addition to an atrophy of the outer retina, affected individuals present with a characteristic atrophy of the choroid. To search for a canine model, we screened the CHM gene of 37 dogs (22 breeds) with various forms of retinal dystrophies. We found 21 variations in 13 breeds (17 detected in only one breed and 4 shared by two or more) with 43% segregating in the same pedigree, a Great Dane female and a female offspring. Of particular interest were an exonic missense variation and a 3-bp intronic deletion near a splice acceptor site. However, although not detected in unrelated healthy Great Danes, these variants were nonpathogenic since they did not segregate with the disease phenotype in the pedigree. These results suggest that a CHM dog model may not be viable, as is the case for mouse and zebrafish

Present and future avenues of cell‐based therapy for brain injury: The enteric nervous system as a potential cell source

International audienceCell therapy is a promising strategy in the field of regenerative medicine; however, several concerns limit the effective clinical use, namely a valid cell source. The gastrointestinal tract, which contains a highly organized network of nerves called the enteric nervous system (ENS), is a valuable reservoir of nerve cells. Together with neurons and neuronal precursor cells, it contains glial cells with a well described neurotrophic potential and a newly identified neurogenic one. Recently, enteric glia is looked at as a candidate for cell therapy in intestinal neuropathies. Here, we present the therapeutic potential of the ENS as cell source for brain repair, too. The example of stroke is introduced as a brain injury where cell therapy appears promising. This disease is the first cause of handicap in adults. The therapies developed in recent years allow a partial response to the consequences of the disease. The only prospect of recovery in the chronic phase is currently based on rehabilitation. The urgency to offer other treatments is therefore tangible. In the first part of the review, some elements of stroke pathophysiology are presented. An update on the available therapeutic strategies is provided, focusing on cell- and biomaterial-based approaches. Following, the ENS is presented with its anatomical and functional characteristics, focusing on glial cells. The properties of these cells are depicted, with particular attention to their neurotrophic and, recently identified, neurogenic properties. Finally, preliminary data on a possible therapeutic approach combining ENS-derived cells and a biomaterial are presente

FIVE-WEEK NERVE GROWTH FACTOR TREATMENT IS SAFE FOR BRAIN REPAIR

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A Reproducible New Model of Focal Ischemic Injury in the Marmoset Monkey: MRI and Behavioural Follow-Up

International audienceIschemic stroke mostly affects the primary motor cortex and descending motor fibres, with consequent motor impairment. Pre-clinical models of stroke with reproducible and long-lasting sensorimotor deficits in higher-order animals are lacking. We describe a new method to induce focal brain damage targeting the motor cortex to study damage to the descending motor tracts in the non-human primate. Stereotaxic injection of malonate into the primary motor cortex produced a focal lesion in middle-aged marmosets (Callithrix jacchus). Assessment of sensorimotor function using a neurological scale and testing of forelimb dexterity and strength lasted a minimum of 12 weeks. Lesion evolution was followed by magnetic resonance imaging (MRI) at 24 h, 1 week, 4 and 12 weeks post-injury and before sacrifice for immunohistochemistry. Our model produced consistent lesions of the motor cortex, subcortical white matter and caudate nucleus. All animals displayed partial spontaneous recovery with long lasting motor deficits of force (54% loss) and dexterity (≈ 70% loss). Clearly visible T2 hypointensity in the white matter was observed with MRI and corresponded to areas of chronic gliosis in the internal capsule and lenticular fasciculus. We describe a straightforward procedure to reproducibly injure the motor cortex in the marmoset monkey, causing long-lasting motor deficits. The MRI signature reflects Wallerian degeneration and remote injury of corticospinal and corticopontine tracts, as well as subcortical motor loops. Our model may be suitable for the testing of therapies for post-stroke recovery, particularly in the chronic phase

FIVE-WEEK INTRANASAL NERVE GROWTH FACTOR TREATMENT IS SAFE AND FAVORS BRAIN NEUROGENESIS

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PenBase, the shrimp antimicrobial peptide penaeidin database: Sequence-based classification and recommended nomenclature

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