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N Cartier

Publications and source records attributed to N Cartier.

At least 19 recordsLinked to original sources
PubMed2006

Partial cure of established disease in an animal model of metachromatic leukodystrophy after intracerebral adeno-associated virus-mediated gene transfer.

Metachromatic leukodystrophy (MLD) is a lysosomal storage disease caused by genetic deficiency of arylsulfatase A (ARSA) enzyme. Failure in catalyzing the degradation of its major substrate, sulfatide (Sulf), in oligodendrocytes and Schwann cells leads to severe demyelination in the peripheral (PNS) and central nervous system (CNS), and early death of MLD patients. The ARSA knockout mice develop a disease that resembles MLD but is milder, without significant demyelination in the PNS and CNS. We showed that adeno-associated virus serotype 5-mediated gene transfer in the brain of ARSA knockout mice reverses Sulf storage and prevents neuropathological abnormalities and neuromotor disabilities when vector injections are performed at a pre-symptomatic stage of disease. Direct injection of viral particles into the brain of ARSA knockout mice at a symptomatic stage results in sustained expression of ARSA, prevention of Sulf storage and neuropathological abnormalities. Despite these significant corrections, the treated mice continue to develop neuromotor disability. We show that more subtle biochemical abnormalities involving gangliosides and galactocerebroside are in fact not corrected.

Animals↗
PubMed2001

Gene therapy strategies for X-linked adrenoleukodystrophy.

X-linked adrenoleukodystrophy (ALD) is the most frequently seen genetic disorder involving the myelin of the central nervous system. The cerebral form affects mainly boys between five to 12 years, leading to vegetative state or death within two to four years. The adult form affects the spinal cord, leading to severe paraplegia often complicated by cerebral demyelination. The ALD gene encodes an ATP-binding cassette transporter involved in the transport of very long chain fatty acids into peroxysomes. Specific subpopulations of oligodendrocytes and microglia are particularly affected by the ALD gene mutation and thus should be the target cells of gene therapy approaches. Two different and potentially complementary therapeutic strategies are currently evaluated. The first approach aims at replacing the endogenous brain microglia from patients by autotransplantation of genetically corrected hematopoietic stem cells using a lentiviral vector. The second approach aims at targeting directly the ALD gene into brain glial cells using stereotactic injections of viral vectors.

Adrenoleukodystrophy↗
PubMed2000

Simvastatin does not normalize very long chain fatty acids in adrenoleukodystrophy mice.

X-linked adrenoleukodystrophy (ALD) is a genetic demyelinating disorder characterized by accumulation of very long chain fatty acid (VLCFA) in tissues. Lovastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, normalizes VLCFA in fibroblasts and plasma from ALD patients. We dietary treated ALD mice with simvastatin, an analog of lovastatin with similar pharmacokinetics and effects on plasma VLCFA in ALD patients at 20 or 60 mg/kg/day for 6-12 weeks. No decrease of VLCFA content was observed in mouse tissues, including the brain. A significant increase of VLCFA was rather observed in the brain of ALD mice at 60 mg/kg/day.

Adrenal Glands↗
PubMed1999

Homo- and heterodimerization of peroxisomal ATP-binding cassette half-transporters.

Mammalian peroxisomal proteins adrenoleukodystrophy protein (ALDP), adrenoleukodystrophy-related protein (ALDRP), and 70-kDa peroxisomal protein (PMP70) belong to the superfamily of ATP-binding cassette (ABC) transporters. Unlike many ABC transporters that are single functional proteins with two related halves, ALDP, ALDRP, and PMP70 have the structure of ABC half-transporters. The dysfunction of ALDP is responsible for X-linked adrenoleukodystrophy (X-ALD), a neurodegenerative disorder in which saturated very long-chain fatty acids accumulate because of their impaired peroxisomal beta-oxidation. No disease has so far been associated with mutations of adrenoleukodystrophy-related or PMP70 genes. It has been proposed that peroxisomal ABC transporters need to dimerize to exert import functions. Using the yeast two-hybrid system, we show that homo- as well as heterodimerization occur between the carboxyl-terminal halves of ALDP, ALDRP, and PMP70. Two X-ALD disease mutations located in the carboxyl-terminal half of ALDP affect both homo- and heterodimerization of ALDP. Co-immunoprecipitation demonstrated the homodimerization of ALDP, the heterodimerization of ALDP with PMP70 or ALDRP, and the heterodimerization of ALDRP with PMP70. These results provide the first evidence of both homo- and heterodimerization of mammalian ABC half-transporters and suggest that the loss of ALDP dimerization plays a role in X-ALD pathogenesis.

ATP Binding Cassette Transporter, Subfamily D↗
PubMed1999

Retroviral-mediated adrenoleukodystrophy-related gene transfer corrects very long chain fatty acid metabolism in adrenoleukodystrophy fibroblasts: implications for therapy.

X-linked adrenoleukodystrophy is a demyelinating disorder of the central nervous system with an impaired very long chain fatty acid metabolism. The adrenoleukodystrophy gene encodes a peroxisomal membrane protein that is part of a family of related ATP-binding transporters including the adrenoleukodystrophy-related protein. The adrenoleukodystrophy protein and adrenoleukodystrophy-related protein show 66% identity and have a mirror expression in most mouse tissues. We show that retroviral-mediated adrenoleukodystrophy-related gene transfer corrects very long chain fatty acid accumulation in adrenoleukodystrophy fibroblasts, irrespective of the presence or absence of adrenoleukodystrophy protein. Pharmacological approaches aiming at overexpressing the adrenoleukodystrophy-related gene in the central nervous system of adrenoleukodystrophy patients might thus offer new therapeutic leads.

Adrenoleukodystrophy↗
PubMed1998

Retroviral transfer and long-term expression of the adrenoleukodystrophy gene in human CD34+ cells.

Adrenoleukodystrophy (ALD) is a demyelinating disease of the central nervous system that results from a genetic deficiency of ALDP, an ABC protein involved in the transport of very long-chain fatty acids (VLCFAs). The cloning of the ALD gene and the positive effects of allogeneic bone marrow transplantation support the feasibility of a gene therapy approach. We report the retroviral transfer of the ALD cDNA to peripheral blood and bone marrow CD34+ cells from control donors and ALD patients. Prestimulation of these cells with cytokines, followed by infection with the M48-ALD retroviral vector, resulted in 20% transduction efficiency (4-40%) and expression of the vector-encoded ALDP in 20% of CD34+ cells (7.3-50%). Long-term culture (LTC) of transduced CD34+ cells from two ALD patients showed efficient transduction (24-28%) and stable expression (25-32%) of ALDP in derived clonogenic progenitors at 3 weeks of culture. The expression of ALDP in CFU cells derived from 5 and 6 weeks of LTC confirmed the effective transduction of LTC-initiating cells. Expression of ALDP was observed in CD68+ CFU-derived cells, suggesting that monocyte-macrophages, the target bone marrow cells in ALD, were produced from transduced progenitor cells. VL-CFA content was corrected in LTC and CFU-derived cells in proportion to the percentage of transduced cells, indicating that the vector-encoded ALDP was functional. Although not efficient yet to allow a clinical perspective, these results demonstrate the feasibility of ALD gene transfer into CD34+ cells of ALD patients.

3T3 Cells↗
PubMed1996

Discrete brain areas express the insulin-responsive glucose transporter GLUT4.

Whether or not glucose utilization in the brain is insulin-dependent is still a controversial issue. We looked for the presence of the insulin-sensitive glucose transporter (GLUT4) in rat brain and obtained the following results: (1) poly(A) RNAs from the hypothalamus and anterior medulla oblongata hybridize with a cDNA probe for GLUT4; (2) reverse transcription-polymerase chain reaction (RT-PCR) on RNA from various brain nuclei detects GLUT4 transcripts; (3) immunocytochemistry, using a polyclonal antibody to GLUT4; reveals a specific immunostaining pattern, whereas both electronic microscopy and double immunofluorescence staining, using a neurofilament protein marker, indicate a neuronal localization. These results are discussed in terms of a putative neuromodulator role of insulin, via glucose utilization, in brain areas involved in the regulation of fuel metabolism.

Amino Acid Sequence↗
PubMed1995

Retroviral-mediated gene transfer corrects very-long-chain fatty acid metabolism in adrenoleukodystrophy fibroblasts.

Adrenoleukodystrophy (ALD), a lethal demyelinating disease of the brain, is caused by mutations of a gene encoding an ATP-binding transporter, called ALDP, localized in the peroxisomal membrane. It is associated with a defective oxidation of very-long-chain fatty acids, leading to their accumulation in many tissues. This study reports that the retroviral-mediated transfer of the ALD cDNA restored very-long-chain fatty acid oxidation in ALD fibroblasts in vitro following abundant expression and appropriate targeting of the vector-encoded ALDP in peroxisomes. The same method may be used in hematopoietic cells as a further step of a gene therapy approach of ALD.

Adrenoleukodystrophy↗
PubMed1994

Expression of the L-type pyruvate kinase gene and the hepatocyte nuclear factor 4 transcription factor in exocrine and endocrine pancreas.

The L-pyruvate kinase (L-PK) gene is slightly active in normal and tumoral endocrine pancreatic tissues while, in vivo, this gene is not transcribed in the exocrine pancreas. Nevertheless, the L-PK gene is re-expressed at a very low level in cultured 266.6 cells derived from an exocrine pancreas carcinoma. The L-PK gene is early activated in endodermal tissues, e.g. yolk sac and primitive intestine; it remains transcribed in fetal pancreas. In adult, L-PK gene expression is restricted to some endocrine cells. Hepatocyte nuclear factor (HNF) 1 and HNF4 are the main tissue-restricted transcription factors involved in tissue-specific expression of the L-PK gene. HNF1 concentration is similar in liver and all pancreatic cells. HNF4 concentration is high in liver, much lower in islets of Langerhans, endocrine pancreatic tumors, and cultured insulinoma cells, and is scarcely detectable in adult exocrine pancreas. This distribution of HNF4 parallels the expression of the L-PK gene. In vivo footprinting experiments show that the HNF1 binding site is similarly occupied in both adult liver and adult pancreas, in which this gene is practically inactive. In this latter tissue, however, the HNF4 binding site is differently occupied with respect to the liver. Since the chromatin structure remains open around the L-PK promoter in pancreas, the L-PK gene can probably be re-expressed under certain circumstances, for instance in cancerous pancreatic cells.

Animals↗
PubMed1994

Glucose transporter 2 (GLUT 2): expression in specific brain nuclei.

In the brain, certain neurons appear to be sensitive to changes in local and/or plasma glucose concentration. The alterations in the electrical activity of these neurons probably depend on the existence of 'glucose sensors', which may be one of the glucose transporters described so far. Because of suitable kinetic properties, we hypothesized that the glucose transporter 2 (GLUT 2) may well constitute one of the cerebral 'glucose sensors'. In this study, it was demonstrated, using the polymerase chain reaction, that GLUT 2 mRNAs are present in a limited number of brain nuclei, including the nucleus tractus solitarius, the motor nucleus of the vagus, the paraventricular hypothalamic nucleus, the lateral hypothalamic area, the arcuate nucleus and the olfactory bulbs. These localizations were confirmed by immunocytochemistry, but the cerebral distribution of GLUT 2-like immunoreactivity was far larger than initially expected. Furthermore, electron microscopic observations showed that, within the regions examined, GLUT 2 was localized to a restricted population of astrocytes. The localization of GLUT 2 in regions previously connected with feeding behavior supports an indirect role for GLUT 2 in 'glucose sensing' in these specific cerebral structures.

Animals↗
PubMed1994

[The creation of diet-dependent cancer models using transgenesis in animals].

We have created transgenic mice lines in which SV40 T and c-myc expression was controlled by the L-pyruvate kinase gene regulatory region which is responsible for hepatic and pancreatic expression specificity, and strong dependence of this expression upon the carbohydrate composition of the diet. Models of hepatoma and endocrine pancreatic tumors have been obtained. Both tumors were dependent upon the diet, since carbohydrates strongly increased frequency and precocity of both hepatic and pancreatic carcinomas.

Animals↗
PubMed1994

[Medium-chain acyl-CoA dehydrogenase deficiency: contribution of molecular biology].

BACKGROUND: Medium-chain acyl-CoA dehydrogenase deficiency is the most frequent cause of defective congenital fatty acid oxidation. Its molecular characterization is now possible. Case n. 1. A girl, 15 month-old, was admitted because she suffered from fever and vomiting, requiring the administration of aspirin. One day later, she showed signs of drowsiness and hypotonia; her blood glucose concentration was 0.3 g/l. She was given intravenous glucose and this episode rapidly passed. Case n. 2. A boy, brother of the preceding patient, was routinely investigated; he was never symptomatic. Case n. 3. A boy, sibling of the two preceding children, was admitted at the age of 18 months because he had gone into a coma during a febrile episode. His blood glucose concentration was 0.15 g/l. This episode was rapidly resolved by a glucose infusion. His fasting blood concentrations of glucose, non esterified fatty acids. beta-hydroxybutyrate, lactate and pyruvate were normal as were his blood carnitine and ammonia, but he showed elevated urinary excretion of dicarboxylic acids. METHODS: Genomic DNA was extracted from peripheral leukocytes of the three sibs and their parents. The A-->G mutation at nucleotide 985 of the MCAD gene was detected by amplification and creation of a restriction site (ACRS). The implicated segment of this gene was amplified by PCR. RESULTS: ACRS showed that the symptomatic children were homozygous for the A-->G mutation, whereas their parents were heterozygous. The third asymptomatic child did not carry the mutation. CONCLUSIONS: Molecular biology techniques are appropriate for diagnosing this potentially lethal disease and their use for screening is important for disease prevention.

Acyl-CoA Dehydrogenases↗
PubMed1994

[Creation of diet-dependent cancer models in transgenic animals].

We have created transgenic mice lines in which SV40 T and c-myc expression was controlled by the L-pyruvate kinase gene regulatory region which is responsible for hepatic and pancreatic expression specificity, and strong dependence of this expression upon the carbohydrate composition of the diet. Models of hepatoma and endocrine pancreatic tumors have been obtained. Both tumors were dependent upon the diet, since carbohydrates strongly increased frequency and precocity of both hepatic and pancreatic carcinomas.

Animals↗
PubMed1993

A two-year trial of oleic and erucic acids ("Lorenzo's oil") as treatment for adrenomyeloneuropathy.

BACKGROUND: Adrenomyeloneuropathy is an X-linked recessive disorder characterized by myelopathy, peripheral neuropathy, and cerebral demyelination, which develop in association with the accumulation of very-long-chain fatty acids. The administration of oleic and erucic acids inhibits the synthesis of very-long-chain fatty acids. Recently such dietary treatment has been widely publicized as a possible cure for this disease. METHODS: We conducted an open trial in 14 men with adrenomyeloneuropathy, 5 symptomatic heterozygous women, and 5 boys (mean age, 13 years) with preclinical adrenomyeloneuropathy. The patients ate a low-fat diet and received daily doses of glycerol trioleate oil (1.7 g per kilogram of body weight) and glycerol trierucate oil (0.3 g per kilogram). Clinical manifestations, cerebral and spinal cord magnetic resonance imaging (MRI) scans, nerve conduction, and brain-stem auditory and somatosensory evoked potentials were studied prospectively over 18 to 48 months. Plasma levels of very-long-chain fatty acids and the side effects of erucic acid were monitored monthly. RESULTS: By week 10, plasma very-long-chain fatty acid levels declined nearly to normal. Nonetheless, over a mean follow-up of 33 months none of the 14 men with adrenomyeloneuropathy improved. In nine men there was functional deterioration, coincident in four with new cerebral lesions on MRI. In a single patient there was a reduction in cerebellar demyelination, but without clinical improvement. In one of the five asymptomatic boys signs of myelopathy developed. There were no changes in the symptomatic heterozygous women. There was some improvement in peroneal-nerve conduction, but no detectable clinical improvement. Conduction to the parietal cortex (T12-P37 interpeak latency) worsened in both the symptomatic men and the boys with preclinical adrenomyeloneuropathy. There was no change in other somatosensory evoked potentials or in brain-stem auditory evoked potentials. Asymptomatic thrombocytopenia (< 100,000 cells per cubic millimeter) was noted in six patients. CONCLUSIONS: In this open trial we found no evidence of a clinically relevant benefit from dietary treatment with oleic and erucic acids ("Lorenzo's oil") in patients with adrenomyeloneuropathy.

Adolescent↗
PubMed1993

Abnormal messenger RNA expression and a missense mutation in patients with X-linked adrenoleukodystrophy.

A candidate gene for X-linked adrenoleukodystrophy (ALD) has been identified via positional cloning strategies. We now report messenger RNA expression in fibroblasts from 6 unrelated ALD patients. Four patients lacked the normal 4.2 kb transcript, three of them having deletions of the ALD gene. A fifth patient with a deletion of 1.6 kb had a smaller 4.0 kb transcript. The last patient had a normal sized transcript and a missense mutation at base 1258 leading to Glu-291-Lys substitution in a region of the candidate gene protein which is conserved in the 70 kD peroxisomal membrane protein. These results provide further evidence that this candidate gene is indeed the ALD gene.

ATP-Binding Cassette Transporters↗
PubMed1993

Establishment of renal proximal tubule cell lines by targeted oncogenesis in transgenic mice using the L-pyruvate kinase-SV40 (T) antigen hybrid gene.

Targeted oncogenesis allowed us to obtain two cell lines which have been derived from the proximal tubule of kidney from transgenic mice harbouring the simian virus (SV40) large T and small t antigens placed under the control of the 5' regulatory sequence from the rat L-type pyruvate kinase (L-PK) gene. The cell lines (PKSV-PCT and PKSV-PR cells) were derived from early (PCT) and late (Pars Recta, PR) microdissected proximal tubules grown in D-glucose-enriched medium. In such conditions of culture, both cell lines exhibited L-PK transcripts, a stable expression of SV40-encoded nuclear large T antigen, a prolonged life span but failed to induce tumors when injected sub-cutaneously into athymic (nu-nu) mice. Confluent cells, grown on plastic support or porous filters, were organized as monolayers of polarized cuboid cells with well developed apical microvilli and formed domes. Both cell lines exhibited morphological features of proximal tubule cells with villin located in the apical brush-border and substantial amounts of hydrolase activity. By immunofluorescence studies using specific antibodies, aminopeptidase N appeared restricted to the apical microvillar domain, whereas the H2 histocompatibility antigen was distributed in the cytoplasm and lateral membranes. These results demonstrate that the proximal morphological phenotype has been fully preserved in these cultured cells derived from tissue-specific targeted oncogenesis in transgenic mice.

Aminopeptidases↗
PubMed1993

Functional properties of proximal tubule cell lines derived from transgenic mice harboring L-pyruvate kinase-SV40 (T) antigen hybrid gene.

This study describes the functional characterization of two cell lines derived from the proximal convoluted (PKSV-PCT cells) and proximal straight (PKSV-PR) tubules microdissected out from kidneys of transgenic mice harboring the simian virus 40 (SV40) large T and small t antigens placed under the control of the rat L-type pyruvate kinase (L-PK) 5' regulatory sequence. Both cell lines exhibited cellular cyclic AMP stimulated by parathormone (PTH) and calcitonin (CT) and a sodium-dependent glucose transporter. Uptake of the fluid-phase marker [3H]inulin showed that both cell lines grown on filters exhibited biphasic apical and basolateral endocytic rates. Results from Northern blot analysis indicate that the expression of the T antigen gene (Tag) is dependent on the concentration of D-glucose in the medium and show that the L-PK construct has maintained its capacity for up- or down-regulation by carbohydrates. Replacement of D-glucose by neoglucogenic substrates (lactate, oxaloacetate) blunted the expression of Tag transcripts and induced arrest of cell growth. Compared to cell grown in D-glucose-enriched medium, the hormonal sensitivities to PTH and CT and the sodium-dependent glucose uptake were unchanged whereas quiescent cells exhibited increased hydrolase content. Thus the proximal function has been preserved in these cultured cells derived from tissue-specific targeted oncogenesis in transgenic mice. As the expression of Tag transcripts is controlled by D-glucose, the structural and physiological characteristics of these cell lines can be studied in either quiescent or active growth conditions.

Animals↗