Lipid Nanoparticles Vectorized with NFL-TBS.40-63 Peptide Target Oligodendrocytes and Promote Neurotrophin-3 Effects After Demyelination In Vitro.

Promoting remyelination in multiple sclerosis is important to prevent axon degeneration, given the lack of curative treatment. Although some growth factors improve this repair, unspecific delivery to cells and potential side effects limit their therapeutic use. Thus, NFL-TBS.

Neurofilaments and NFL-TBS.40-63 peptide penetrate oligodendrocytes through clathrin-dependent endocytosis to promote their growth and survival in vitro.

Neurofilaments (NF) are released into the cerebrospinal fluid (CSF) during multiple sclerosis (MS), but their role outside the axon is still unknown. In vitro NF fractions, as well as tubulin (TUB), increase oligodendrocyte (OL) progenitor proliferation and/or their differentiation depending on the stage of their purification (Fressinaud et al., 2012).

Neurofilament-tubulin binding site peptide NFL-TBS.40-63 increases the differentiation of oligodendrocytes in vitro and partially prevents them from lysophosphatidyl choline toxiciy.

During multiple sclerosis (MS), the main axon cystoskeleton proteins, neurofilaments (NF), are altered, and their release into the cerebrospinal fluid correlates with disease severity. The role of NF in the extraaxonal location is unknown. Therefore, we tested whether synthetic peptides corresponding to the tubulin-binding site (TBS) sequence identified on light NF chain (NFL-TBS.

Axoskeletal proteins prevent oligodendrocyte from toxic injury by upregulating survival, proliferation, and differentiation in vitro.

Neurofilaments (NF) are detected in the cerebrospinal fluid of multiple sclerosis (MS) patients, and their concentration correlates with disease severity. We recently demonstrated that NF and co-isolated proteins increase the proliferation and differentiation of oligodendrocytes (OL) in vitro. If these proteins are released in the extracellular environment in MS, they might then regulate remyelination by OL.

Axon cytoskeleton proteins specifically modulate oligodendrocyte growth and differentiation in vitro.

In multiple sclerosis (MS) remyelination by oligodendrocytes (OL) is incomplete, and it is associated with a decrease in axonal neurofilaments (NF) and tubulin (TUB). To determine whether these proteins could participate directly in MS remyelination failure, or indirectly through proteins that are co-associated, we have analysed their effects in pure OL cultures. Rat brain NF fractions, recovered by successive centrifugations increase either OL progenitor (OLP) proliferation (2nd pellet, P2), or only their maturation (P5), whereas albumin, liver and skin proteins, as well as recombinant GFAP or purified actin were ineffective.

Axon cytoskeleton ultrastructure in chronic inflammatory demyelinating polyneuropathy.

Introduction: To detail the extent and pattern of axon cytoskeleton alterations in chronic inflammatory demyelinating polyneuropathy (CIDP).

Methods: Nerve biopsies from 7 cases of CIDP, including 4 cases with severe fiber loss, were compared with 5 controls by morphometric transmission electron microscopy (TEM).

Results: Despite demyelination of single fibers, myelin ultrastructure was otherwise normal.

[Oligodendroglial defect and insufficiency of remyelination during MS: anatomoclinical and experimental comparative study].

Introduction: The mechanisms responsible for the failure of remyelination during MS are poorly understood. We have analyzed in which way oligodendrocytes (OL) could be involved.

Methods: The number of remyelinated fiber per OL has been determined in 18 chronic MS lesions and compared to normal appearing white matter (NAWM), as well as in the center of lysophosphatidyl choline (LPC)-induced lesions in adult rats in which remyelination was accelerated by microinjection of neurotrophin-3 (NT-3).

[Lesion mechanism dependent, differential changes in neurofilaments and microtubules: a pathological and experimental study].

Introduction: The consequences of axonal or demyelinating injuries on the axonal cytoskeleton have rarely been described.

Methods: We have compared the density of fibers labeled by anti-neurofilaments (NF) and -beta tubulin (TUB) to the density of total fibers in nine patients with axonal neuropathies of undetermined etiology (AUE), six with necrotizing angeitis with neuropathy (NAN), seven with chronic inflammatory demyelinating neuropathy (CIDP) and in five controls, as well as in six patients with chronic multiple sclerosis (MS). We also studied demyelinated rat corpus callosum after lysophosphatidyl (LPC) microinjection.

Repeated injuries dramatically affect cells of the oligodendrocyte lineage: effects of PDGF and NT-3 in vitro.

In multiple sclerosis, relapses occur and remyelination is incomplete, whereas one demyelinating lesion induced by lysophosphatidyl choline (LPC) in rats is completely remyelinated; this process is accelerated by platelet-derived growth factor (PDGF) (Allamargot et al.: Brain Res 918:28-39,2001) and neurotrophin-3 (NT-3) (Jean et al.: Brain Res 972:110-118,2003).

Spontaneous central nervous system remyelination is not altered in NFH-lacZ transgenic mice after chemical demyelination.

Harmonious functioning of the nervous system depends on neuron-glia interactions, particularly between the axons and their myelinating cells, i.e., oligodendrocytes (OL) in the central nervous system (CNS).

Neurotrophin-3 specifically increases mature oligodendrocyte population and enhances remyelination after chemical demyelination of adult rat CNS.

In human central nervous system (CNS) demyelinating diseases, spontaneous remyelination is often incomplete. Therefore, we have tested whether neutrotrophin-3 (NT-3) accelerates CNS myelin repair after a chemically-induced demyelination. One group of adult rats was injected in the corpus callosum (CC) with 1 microl of 1% lysophosphatidylcholine (LPC) and 1 microl of NT-3 (1 microg/microl), and 15 days after injury (D15) remyelination was compared to control rats (receiving 1 microl of LPC+1 microl of vehicle buffer of NT-3).

[Necrotizing vasculitis of the peripheral nervous system: comparison of the axon cytoskeleton abnormalities with other types of neuropathies].

Morphometric and immunocytochemical data obtained from nerve biopsies in six patients with necrotizing angiopathic neuropathy were compared with the data obtained in five control patients without neurologic disease. The density of myelinated fibers were greatly decreased in all patients (more than 55 p.cent), and reached 70 p.

Selective decrease in axonal nerve growth factor and insulin-like growth factor I immunoreactivity in axonopathies of unknown etiology.

In an attempt to approach the mechanisms underlying axonopathies of unknown etiology, we have studied by immunocytochemistry the fate of several growth factors in eight of such cases that we had previously analyzed by morphometry and which were characterized by a decrease in neurofilaments and an increase in beta tubulin immunostaining. Here we establish that, contrary to beta tubulin, growth-associated protein43 (GAP-43) immunolabeling is not up-regulated in theses cases, correlating well with the failure of regeneration. Neurotrophin-3 (NT-3) and its receptor TrkC were not modified compared to controls (five cases).

[Chronic inflammatory polyradiculoneuritis and the axonal cytoskeleton: morphometric and immunocytochemical data].

We report morphometric and immunocytochemical data obtained from nervous biopsy in 7 patients with chronic inflammatory demyelinating neuropathy (CIDP), compared to 5 controls (without neurological involvement). Fiber loss was present in all cases and reached 50 p. 100 or more in 4 cases.

[Isolated angiitis of the central nervous system. Report of two cases and review of the literature].

Isolated angiitis of the central nervous system is a rare disease affecting mainly adults of both sex; about 210 cases have been reported. Contrary to other inflammatory arteritis, arthralgia, myalgia, weight loss and fever are exceptional and symptoms are mainly neurologic, but none is specific. The diagnosis is evoked in case of headaches and cognitive impairment, associated or not with multifocal neurologic signs.

Axonal lesions and PDGF-enhanced remyelination in the rat corpus callosum after lysolecithin demyelination.

In multiple sclerosis (MS), demyelination is often accompanied by axonal lesions, which largely account for patient disability. We therefore studied the consequences of demyelination induced by lysophosphatidylcholine (LPC) on the axonal cytoskeleton, particularly neurofilaments (NF) and tubulin, in the adult rat corpus callosum. Immunocytochemistry showed that NF immunolabelled fibres decreased by 49% in the LPC injured area at day 15.

Cytoskeleton abnormalities in axonopathies of unknown aetiology: correlations with morphometry.

To determine if specific axonal cytoskeleton abnormalities could be demonstrated in axonopathies without aetiology, nerve biopsies from five controls and nine cases were analyzed by morphometry and immunocytochemistry with anti-neurofilament (NF, subunits L, M, H) and anti-beta tubulin (TUB) antibodies. Morphometry revealed either large fiber atrophy (decrease in large fiber density with increased density in small fibers), degeneration of large fibers (decrease in large fiber density and in total density of fibers) or of all diameter fibers. NF immunostaining density decreased (by 21-89%) only in cases with fiber loss, in parallel to myelinated fiber density as determined by morphometry.

A single intracerebral microinjection of platelet-derived growth factor (PDGF) accelerates the rate of remyelination in vivo.

We had demonstrated that platelet-derived growth factor (PDGF) enhanced the reconstruction of myelin-like membranes after their disruption by lysophosphatidylcholine (LPC) in vitro. To investigate its role in vivo, a demyelinating lesion of the corpus callosum was induced in adult Wistar rats by a stereotaxic microinjection of 1 microl LPC, then 63 pairs of rats received either 1 microg PDGF, or its vehicle buffer which were injected above LPC. The effects of PDGF were significant after 2 weeks: the number of oligodendrocytes (OL) expressing 2',3'-cyclic nucleotide 3'-phosphodiesterase in the lesion increased by 49%, mature OL labelled by in situ hybridization for myelin basic protein-mRNA increased by 27% (P<10(-2)), and the total volume of demyelination decreased by 60% compared to controls.

[Unusual complication of rendu-osler-weber disease: paramedian bulbar syndrome].

We report a case of arteriovenous malformation of the brainstem, revealed by a progressive right pyramidal syndrome and an atrophy of the left hemi-tongue in a man presenting a Rendu-Osler-Weber disease. After embolization the clinical course was stationary.

Glutamine synthetase expression and activity are regulated by 3,5,3'-triodo-L-thyronine and hydrocortisone in rat oligodendrocyte cultures.

Glutamine synthetase plays a central role in the detoxification of brain ammonia. Previously, we demonstrated that in vitro glutamine synthetase is expressed by all macroglial cell types and is developmentally regulated in oligodendrocyte lineage. Furthermore, glutamine synthetase is increased in secondary cultures of oligodendrocytes following a 72 h treatment with 30 nM 3,5,3'-triodo-L-thyronine [Baas, D.

Oligodendrocyte-type-2 astrocyte (O-2A) progenitor cells express glutamine synthetase: developmental and cell type-specific regulation.

Glutamine synthetase (GS), the enzyme that catalyses glutamine synthesis from glutamate and ammonia, plays a central role in the detoxification of brain ammonia. In the central nervous system (CNS), GS also subserves additional important functions such as regulating glutamate, GABA and amino acid metabolism. Oligodendrocytes (OL) form the myelin sheath in the central nervous system (CNS) and are essential for efficient propagation of nerve impulses.

Platelet-derived growth factor partly prevents chemically induced oligodendrocyte death and improves myelin-like membranes repair in vitro.

We have previously shown that pure oligodendrocyte (OL) secondary cultures derived from newborn rat brain, in which cells form myelin-like membranes, can be used as a model to investigate the putative role of growth factors in myelin repair. After disruption of these membranes by lysophosphatidylcholine (LPC), a 3 day treatment with 10 ng/ml basic fibroblast growth factor (bFGF) induced reconstruction of myelin figures, albeit less compacted than in untreated controls. Here we show that in LPC treated cultures: 1) bFGF can not prevent OL from LPC-induced cell death; 2) platelet-derived growth factor (PDGF) pretreatment although preventing some cell death does not improve recovery compared to delayed treatment; 3) PDGF is as potent as bFGF in terms of O-2A progenitor proliferation; 4) PDGF is far more effective than bFGF, inducing the reappearance of more myelin-like structures with a better compaction; 5) there is no potentiation between these growth factors; and 6) after withdrawal of bFGF the compaction of myelin figures partly increases.

Basic fibroblast growth factor down-regulates myelin basic protein gene expression and alters myelin compaction of mature oligodendrocytes in vitro.

The effects of basic fibroblast growth factor (bFGF) on myelin basic protein (MBP) gene expression and myelin-like membrane formation were investigated in oligodendrocyte cultures containing mainly mature oligodendrocytes expressing MBP. These cultures were obtained by selective detachment of the cells of the oligodendrocyte lineage from 40-day-old mixed cultures derived from newborn rat brain. They were further purified by a 3-day pretreatment with cytosine arabinoside (ARA-C) in order to kill cycling cells.

Expression of thyroid hormone receptor isoforms in rat oligodendrocyte cultures. Effect of 3,5,3'-triiodo-L-thyronine.

3,5,3'-Triiodo-L-thyronine (T3) acts at the genomic level by interacting with nuclear T3 receptors (T3Rs). We have used double immunostaining to follow the expression of T3Rs and oligodendrocytes (OL) lineage markers in rat secondary cultures consisting of 85-90% OL. Using antibodies against different synthetic peptides of T3Rs (alpha common: alpha 1 + alpha 2 and beta 1) we find that alpha-T3R is expressed in both O-2A progenitors and in mature OL, while beta 1-T3R is expressed only in mature OL.

Basic fibroblast growth factor improves recovery after chemically induced breakdown of myelin-like membranes in pure oligodendrocyte cultures.

The putative role of growth factors in remyelination was investigated in pure oligodendrocyte (OL) secondary cultures derived from newborn rat brain. These cells form myelin-like membranes and were used as a model system for toxic attack. A 24 hr treatment with 2.