👤 Giacomo Cavallaro

Alzheimer's disease (AD)'s multifactorial nature stresses the role of epigenetics in affecting different pathological pathways. We demonstrated that one-carbon metabolism epigenetically impacts AD-like phenotype. Here, we investigated the crosstalk between methylation and microRNAs in AD. We altered one-carbon metabolism to induce hypo- and hyper-methylation, in SK-N-BE neuroblastoma cells and TgCRND8 mice. miRNAs were profiled through a polymerase chain reaction array, then we focused on miR-29a expression and methylation of its genomic locus. Finally, we assessed miR-29a expression and methylation in the brain of AD subjects. MiR-29a was repressed in hypomethylating and expressed in hypermethylating conditions. The expression of miR-29a and of its target, BACE1, was inversely correlated. We demonstrated for the first time that miR-29a is modulated by one-carbon metabolism through DNA methylation, disclosing the molecular mechanisms regulating BACE1 expression in AD. These data confirm miR-29a's protective role in AD and support miR-29a as a potential biomarker for AD. Show less

Besides its role in coagulation, vitamin K seems to be involved in various other mechanisms, including inflammation and age-related diseases, also at the level of gene expression. This work examined the roles of two vitamin K2 (menaquinones) vitamers, namely, menaquinone-4 (MK4) and reduced menaquinone-7 (MK7R), as gene modulator compounds, as well as their potential role in the epigenetic regulation of genes involved in amyloidogenesis and neuroinflammation. The SK-N-BE human neuroblastoma cells provided a "first-line" model for screening the neuroinflammatory and neurodegenerative molecular pathways. MK7R, being a new vitamin K form, was first tested in terms of solubilization, uptake and cell viability, together with MK4 as an endogenous control. We assessed the expression of key factors in amyloidogenesis and neuroinflammation, observing that the MK7R treatment was associated with the downregulation of neurodegeneration- ( Show less

Beyond deficits in hippocampal-dependent episodic memory, Alzheimer's Disease (AD) features sensory impairment in visual cognition consistent with extensive neuropathology in the retina. 12A12 is a monoclonal cleavage specific antibody (mAb) that in vivo selectively neutralizes the AD-relevant, harmful N-terminal 20-22 kDa tau fragment(s) (i.e., NH Show less

The p.Thr1406Asn (rs1047891) polymorphism of the carbamoyl-phosphate synthetase 1 (CPS1) gene has been linked to functional consequences affecting the downstream availability of the nitric oxide precursor L-arginine. L-arginine concentrations are decreased in preterm infants with necrotizing enterocolitis (NEC). In this multicenter prospective study, we investigated the association of the p.Thr1406Asn polymorphism with NEC in 477 preterm infants (36 cases of NEC) from 4 European neonatal intensive care units (Maastricht, Las Palmas de Gran Canaria, Mantova, and Milan). Allele and genotype frequencies of the p.Thr1406Asn polymorphism did not significantly differ between the infants with and without NEC. In contrast, the minor A-allele was significantly less frequent in the group of 64 infants with the combined outcome NEC or death before 34 weeks of corrected gestational age than in the infants without the outcome (0.20 vs. 0.31, P = 0.03). In addition, a significant negative association of the A-allele with the combined outcome NEC or death was found using the dominant (adjusted odds ratio, aOR: 0.54, 95% CI 0.29-0.99) and the additive (aOR 0.58, 95% CI 0.36-0.93) genetic models. In conclusion, our study provides further evidence that a functional variant of the CPS1 gene may contribute to NEC susceptibility. Show less

The development of neuronal apoptosis depends on an intrinsic transcriptional program. By DNA microarray technology, we have previously implicated a number of genes in different paradigms of neuronal apoptosis. In the present study, we investigated the spatiotemporal pattern of expression of two of these genes, gastric inhibitory polypeptide (Gip) and its receptor (Gipr) in the rat central nervous system. The levels of their transcripts were measured with real-time quantitative polymerase chain reaction and in situ-hybridization. Widespread expression of Gip and Gipr was found in adult rat brain, whereas during postnatal cerebellum development, they were highly expressed in the external and internal granule layer, and in Purkinje cells. To investigate the possible biological function of Gip we examined its effects in vitro. Addition of Gip to cultured cerebellar granule neurons reduced the extent of apoptotic death induced by switching the growing medium from 25 to 5 mM K+. This neurotrophic effect was mimicked by that of PACAP38 and IGF1. We conclude that Gip acts as an endogenous neurotrophic factor and supports neuronal survival. Show less

A C-to-A nucleotide transversion (T1405N) in the gene that encodes carbamoyl-phosphate synthetase 1 (CPS1) has been associated with changes in plasma concentrations of L-arginine in term and near term infants but not in adults. In preterm infants homozygosity for the CPS1 Thr1405 variant (CC genotype) was associated with an increased risk of having necrotizing enterocolitis (NEC). Plasma L-arginine concentrations are decreased in preterm infants with NEC. To examine the putative association between the CPS1 T1405N polymorphism and plasma arginine concentrations in preterm infants. Prospective multicenter cohort study. Plasma and DNA samples were collected from 128 preterm infants (<30 weeks) between 6 and 12 hours after birth. Plasma amino acid and CPS1 T1405N polymorphism analysis were performed. Distribution of genotypes did not differ between the preterm (CC:CA:AA = 55.5%:33.6%:10.9%, n = 128) and term infants (CC:CA:AA = 54.2%:35.4%:10.4%, n = 96). There was no association between the CPS1 genotype and plasma L-arginine or L-citrulline concentration, or the ornithine to citrulline ratio, which varies inversely with CPS1 activity. Also the levels of asymmetric dimethylarginine, and symmetric dimethylarginine were not significantly different among the three genotypes. The present study in preterm infants did not confirm the earlier reported association between CPS1 genotype and L-arginine levels in term infants. Show less

Many proteins contain ubiquitin-binding domains or motifs (UBDs), such as the UIM (ubiquitin-interacting motif) and are referred to as ubiquitin receptors. Ubiquitin receptors themselves are frequently monoubiquitinated by a process that requires the presence of a UBD and is referred to as coupled monoubiquitination. Using a UIM-containing protein, eps15, as a model, we show here that coupled monoubiquitination strictly depends on the ability of the UIM to bind to monoubiquitin (mUb). We found that the underlying molecular mechanism is based on interaction between the UIM and a ubiquitin ligase (E3), which has itself been modified by ubiquitination. Furthermore, we demonstrate that the in vivo ubiquitination of members of the Nedd4 family of E3 ligases correlates with their ability to monoubiquitinate eps15. Thus, our results clarify the mechanism of coupled monoubiquitination and identify the ubiquitination of E3 ligases as a critical determinant in this process. Show less