Essential role for neuronal nitric oxide synthase in acute ethanol-induced motor impairment.

The cerebellum is widely known as a motor structure because it regulates and controls motor learning, coordination, and balance. However, it is also critical for non-motor functions such as cognitive processing, sensory discrimination, addictive behaviors and mental disorders. The cerebellum has the highest relative abundance of neuronal nitric oxide synthase (nNos) and is sensitive to ethanol. Although it has been demonstrated that the interaction of γ-aminobutyric acid (GABA) and nitric oxide (NO) might play an important role in the regulation of ethanol-induced cerebellar ataxia, the molecular mechanisms through which ethanol regulates nNos function to elicit this behavioral effect have not been studied extensively. Here, we investigated the dose-dependent effects of acute ethanol treatment on motor impairment using the rotarod behavioral paradigm and the alterations of nNos mRNA expression in cerebellum, frontal cortex (FC), hippocampus and striatum. We also examined the link between acute ethanol-induced motor impairment and nNos by pharmacological manipulation of nNos function. We found that acute ethanol induced a dose-dependent elevation of ethanol blood levels which was associated with the impairment of motor coordination performance and decreased expression of cerebellar nNos. In contrast, acute ethanol increased nNos expression in FC but did not to change the expression for this enzyme in striatum and hippocampus. The effects of acute ethanol were attenuated by l-arginine, a precursor for NO and potentiated by 7-nitroindazole (7-NI), a selective inhibitor of nNos. Our data suggests that differential regulation of nNos mRNA expression in cerebellum and frontal cortex might be involved in acute ethanol-induced motor impairment.

Serine Synthesis via PHGDH Is Essential for Heme Production in Endothelial Cells.

The role of phosphoglycerate dehydrogenase (PHGDH), a key enzyme of the serine synthesis pathway (SSP), in endothelial cells (ECs) remains poorly characterized. We report that mouse neonates with EC-specific PHGDH deficiency suffer lethal vascular defects within days of gene inactivation, due to reduced EC proliferation and survival. In addition to nucleotide synthesis impairment, PHGDH knockdown (PHGDHKD) caused oxidative stress, due not only to decreased glutathione and NADPH synthesis but also to mitochondrial dysfunction. Electron transport chain (ETC) enzyme activities were compromised upon PHGDHKD because of insufficient heme production due to cellular serine depletion, not observed in other cell types. As a result of heme depletion, elevated reactive oxygen species levels caused EC demise. Supplementation of hemin in PHGDHKD ECs restored ETC function and rescued the apoptosis and angiogenesis defects. These data argue that ECs die upon PHGDH inhibition, even without external serine deprivation, illustrating an unusual importance of serine synthesis for ECs.

Disturbed phospholipid metabolism in serine biosynthesis defects revealed by metabolomic profiling.

Serine biosynthesis defects are autosomal recessive metabolic disorders resulting from the deficiency of any of the three enzymes involved in de novo serine biosynthesis, specifically phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). In this study, we performed metabolomic profiling on 4 children with serine biosynthesis defects; 3 with PGDH deficiency and 1 with PSAT deficiency. The evaluations were performed at baseline and with serine and glycine supplementation. Metabolomic profiling performed at baseline showed low phospholipid species, including glycerophosphocholine, glycerophosphoethanolamine, and sphingomyelin. All children had low serine and glycine as expected. Low glycerophosphocholine compounds were found in 4 children, low glycerophosphoethanolamine compounds in 3 children, and low sphingomyelin species in 2 children. Metabolic profiling with serine and glycine supplementation showed normalization of most of the low phospholipid compounds in the 4 children. Phospholipids are the major component of plasma and intracellular membranes, and phosphatidylcholine is the most abundant phospholipid of all mammalian cell types and subcellular organelles. Phosphatidylcholine is of particular importance for the nervous system, where it is essential for neuronal differentiation. The observed low phosphatidylcholine species in children with serine biosynthesis defects that improved after serine supplementation, supports the role of serine as a significant precursor for phosphatidylcholine. The vital role that phosphatidylcholine has during neuronal differentiation and the pronounced neurological manifestations in serine biosynthesis defects suggest that phosphatidylcholine deficiency occurring secondary to serine deficiency may have a significant contribution to the development of the neurological manifestations in individuals with serine biosynthesis defects.

A nutrigenomics approach for the study of anti-aging interventions: olive oil phenols and the modulation of gene and microRNA expression profiles in mouse brain.

PURPOSE: Middle-aged C57Bl/6J mice fed for 6 months with extra-virgin olive oil rich in phenols (H-EVOO, phenol dose/day: 6 mg/kg) showed cognitive and motor improvement compared to controls fed the same olive oil deprived of phenolics (L-EVOO). The aim of the present study was to evaluate whether these behavioral modifications were associated with changes in gene and miRNA expression in the brain. METHODS: Two brain areas involved in cognitive and motor processes were chosen: cortex and cerebellum. Gene and miRNA profiling were analyzed by microarray and correlated with performance in behavioral tests. RESULTS: After 6 months, most of the gene expression changes were restricted to the cerebral cortex. The genes modulated by aging were mainly down-regulated, and the treatment with H-EVOO was associated with a significant up-regulation of genes compared to L-EVOO. Among those, we found genes previously associated with synaptic plasticity and with motor and cognitive behavior, such as Notch1, BMPs, NGFR, GLP1R and CRTC3. The agrin pathway was also significantly modulated. miRNAs were mostly up-regulated in old L-EVOO animals compared to young. However, H-EVOO-fed mice cortex displayed miRNA expression profiles similar to those observed in young mice. Sixty-three miRNAs, out of 1203 analyzed, were significantly down-regulated compared to the L-EVOO group; among them, we found miRNAs whose predicted target genes were up-regulated by the treatment, such as mir-484, mir-27, mir-137, mir-30, mir-34 and mir-124. CONCLUSIONS: We are among the first to report that a dietary intervention starting from middle age with food rich in phenols can modulate at the central level the expression of genes and miRNAs involved in neuronal function and synaptic plasticity, along with cognitive, motor and emotional behavior.

Oral administration of curcumin relieves behavioral alterations and oxidative stress in the frontal cortex, hippocampus, and striatum of ovariectomized Wistar rats.

Menopause occurs gradually and is characterized by increased susceptibility to developing mood disorders. Several studies have suggested treatments based on the antioxidant properties of vitamins and herbal compounds as an alternative to hormone replacement therapies, with few or none reporting toxicity. The present study was performed to explore the effects of curcumin oral supplementation on anxiety-like behavior and oxidative stress parameters in different central nervous system (CNS) areas of ovariectomized (OVX) rats. Female Wistar rats were randomly divided into either sham-operated or OVX groups. Sham-operated group (n=8) and an OVX group (n=11) were treated with vehicle, and the other two OVX groups received curcumin at 50 or 100mg/kg/day doses (n=8/group). Elevated plus maze (EPM) test was performed on the 28th day of treatment. On the 30th day, animals were killed and the dissected brain regions were removed and stored at-80°C until analysis. Ovariectomy induced deficit in the locomotor activity and increased anxiety-like behavior. Moreover, OVX rats showed increased lipid oxidized in the frontal cortex and striatum, increased hippocampal and striatal carbonylated protein level, and decreased striatal thiol content of non-protein fraction indicative of a glutathione (GSH) pool. Curcumin oral treatment for 30days reduced oxidative stress in the CNS areas as well as the behavior alterations resulting from ovariectomy. Curcumin supplementation attenuated most of these parameters to sham comparable values, suggesting that curcumin could have positive effects against anxiety-like disturbances and brain oxidative damage due to hormone deprivation.

Neurochemistry in shiverer mouse depicted on MR spectroscopy.

PURPOSE: To evaluate the neurochemical changes associated with hypomyelination, especially to clarify whether increased total N-acetylaspartate (tNAA) with decreased choline (Cho) observed in the thalamus of msd mice with the plp1 mutation is a common finding for hypomyelinating disorders. MATERIALS AND METHODS: We performed magnetic resonance imaging (MRI) and proton MR spectroscopy ((1) H-MRS) of the thalamus and cortex of postnatal 12-week shiverer mice devoid of myelin basic protein (mbp), heterozygous and wild-type mice with a 7.0T magnet. Luxol Fast Blue staining and immunohistochemical analysis with anti-Mbp, Gfap, Olig2, and NeuN antibodies were also performed. RESULTS: In the thalamus, decreased Cho and normal tNAA were observed in shiverer mice. In the cortex, tNAA, Cho, and glutamate were decreased in shiverer mice. Histological and immunohistochemical analysis of shiverer mice brains revealed hypomyelination in the thalamus, white matter, and cortex; astrogliosis and an increased number of total oligodendrocytes in the white matter; and a decreased number of neurons in the cortex. CONCLUSION: The reduction of Cho on (1) H-MRS might be a common marker for hypomyelinating disorders. A normal tNAA level in the thalamus of shiverer mice might be explained by the presence of mature oligodendrocytes, which enable neuron-to-oligodendrocyte NAA transport or NAA catabolism.

Creatine depletion in a new case with AGAT deficiency: clinical and genetic study in a large pedigree.

Arginine:glycine amidinotransferase (AGAT, EC 2.1.4.1) deficiency is a recently recognized autosomal recessive inborn error of creatine biosynthesis, characterized by mental retardation and severe language impairment. We extensively investigated a third 5-year-old patient with AGAT deficiency, discovered in the pedigree of the same Italian family as the two index cases. At the age of 2 years he presented with psychomotor and language delay, and autistic-like behavior. Brain MRI was normal, but brain 1H-MRS disclosed brain creatine depletion, which almost completely normalized following creatine monohydrate supplementation. A remarkable clinical improvement paralleled the restoration of brain creatine concentration. AGAT and GAMT (guanidinoacetate:methyltransferase) genes were analyzed in the proband and in 26 relatives, including the two cousins with AGAT deficiency. Sequencing of the proband's AGAT gene disclosed the same homozygous mutation at nt position 9093 converting a tryptophan (TGG) to a stop codon (TAG) at residue 149 (W149X), as already described in the two previously reported cases. The proband's parents and 10 additional subjects of the pedigree were carriers for this mutation. AGAT deficiency was further confirmed by undetectable AGAT activity in the patient's lymphoblasts. Mutation analysis of the GAMT gene revealed a sequence variation in exon 6 (T209M), not in the proband, but in 15 additional subjects from the pedigree. The silent nature of this sequence variation is supported by its homozygosity in one AGAT deficient cousin and in one asymptomatic adult, both with normal GAMT activity.

Studies on a case of HHH-syndrome (hyperammonemia, hyperornithinemia, homocitrullinuria).

A patient with the hyperornithinemia, hyperammonemia, homocitrullinuria syndrome is described. This patient represents the 12th documented case of this rare, presumably autosomal recessive condition. Increased levels of ammonia, ornithine and homocitrulline were demonstrated in blood and cerebrospinal fluid. The blood ammonia concentration could be lowered by supplementation of the diet with low doses of arginine. High doses of arginine precipitated seizures, although plasma levels of arginine and ornithine were not altered. The uptake of ornithine by the particulate fraction of the patient's fibroblasts was lower than that of controls, but still measurable. It is suggested that HHH patients have a partial impairment of the uptake of ornithine by mitochondria.