Search

Identification of novel targets and biomarkers, such as microRNAs, is extremely helpful to understand the pathogenetic mechanisms in a disease like multiple sclerosis (MS). We tested the expression profile of 1145 microRNAs in peripheral blood mononuclear cells (PBMCs) of 19 MS patients and 14 controls, and we further explored their function by performing a whole-genome mRNA profiling in same subjects and using bioinformatic prediction tool. A total of 104 miRNAs have been identified as deregulated in MS patients; 2/10 which ranked highest (let-7g and miR-150) have been validated in a replication sample, leading to the identification of putative target genes.

Expression of ornithine transcarbamylase (OTC) is strongly induced in the brain of individuals suffering from Alzheimer’s Disease (AD). Association studies in a population from northern France have revealed that two SNPs −389 G/A (rs5963409) and −241 A/G (rs5963411) located in the promoter of the OTC gene are associated with the risk of developing AD. In the present work, these association studies were extended to a population of 2113 AD cases and 1580 controls from northern France, western France, the United Kingdom and Italy. The rs5963409 minor allele was weakly but significantly associated with an increased risk of developing AD (OR = 1.19, p = 0.004). This association was independent of age and ApoE status. Our results support that the OTC gene may be a minor genetic determinant of AD.

Folic acid is believed to play a role in protection from oxidant stress. Low levels of folic acid had been found in serum from patients with Alzheimer disease (AD). Folate concentration was evaluated in sera from 136 patients with cortical dementia [AD, n=108; frontotemporal dementia (FTD), n=28], 57 patients with subcortical dementia [Lewy body disease (LBD), n=9; corticobasal degeneration (CBD), n=5; progressive supranuclear palsy (PSP), n=6; Parkinson disease with dementia (PD-Dem), n=37], and 76 nondemented, healthy age-matched people. Serum folic acid levels were decreased in patients with AD and FTD as compared with either controls or patients with subcortical dementia (3.60+/-2.22 and 5.37+/-2.92 microg/L versus 6.87+/-3.50 microg/L, respectively; P

Interferon-γ-inducible Protein-10 (IP-10) is supposed to play a role in Alzheimer's disease (AD) development, as demonstrated by increased levels in cerebrospinal fluid from patients with AD. A mutation scanning of IP-10 exonic region was carried out in 10 patients with AD and 10 age-matched controls, demonstrating the presence of two previously reported single nucleotide polymorphisms (SNPs) in exon 4 (G → C and T → C) as well as a novel SNP in exon 2 (C → T). Exon 4 G → C and T → C allelic variants were next evaluated in a population of 279 AD patients and 251 controls, in order to determine whether their presence could influence the susceptibility towards the development of the disease. These two SNPs were in complete linkage disequilibrium. No differences in haplotype frequencies were found in AD patients as compared with controls, even stratifying according to the presence of Apolipoprotein E ɛ4 allele, gender or age at onset. A new protocol was developed to easily determine the C → T SNP in exon 2. A preliminary analysis revealed a very low frequency of this allelic variant (1%). Therefore, the complete association study was not carried out because the size of our population was not sufficient to draw reliable conclusions. According to these results, IP-10 does not seem to be a risk factor for AD. However, a novel rare polymorphism has been identified, which could exert a role in AD susceptibility. Thus, further studies on larger populations are needed before confidently excluding IP-10 as a susceptibility gene for AD.

Alzheimer's disease (AD) is considered to be a conformational disease arising from the accumulation of misfolded and unfolded proteins in the endoplasmic reticulum (ER). SEL1L is a component of the ER stress degradation system, which serves to remove unfolded proteins by retrograde degradation using the ubiquitin-proteosome system. In order to identify genetic variations possibly involved in the disease, we analysed the entire SEL1L gene sequence in Italian sporadic AD patients. Here we report on the identification of a new polymorphism within the SEL1L intron 3 (IVS3-88 A>G), which contains potential binding sites for transcription factors involved in ER-induced stress. Our statistical analysis shows a possible role of the novel polymorphism as independent susceptibility factor of Alzheimer's dementia. (C) 2005 Published by Elsevier Ireland Ltd.

P-Selectin (SELP) and P-selectin glycoprotein ligand-1 (SELPLG) constitute a receptor/ligand complex involved in the recruitment of activated lymphocytes, a critical event in the pathogenesis of multiple sclerosis (MS). In order to determine whether genetic variation in these pivotal molecules influences susceptibility to MS, we genotyped 214 Italian patients compared with 220 Italian controls for three single-nucleotide polymorphisms (SNPs): SELPLG Met62Ile, SELP C-2123G and SELP Thr715Pro. No significant differences in both SELP SNPs were found between patients and controls, whereas a decreased frequency of the Met62Ile SNP was found in patients versus controls in the Italian population (P = 0.025). To confirm these preliminary findings, the Met62Ile SNP was analysed in 938 UK trio families. This SNP did not show evidence for association with susceptibility to MS in the larger UK cohort. Therefore, none of the SNPs investigated is associated with MS, although this analysis does not conclusively exclude SELPLG and SELP as genetic risk factors for MS as much variation remains untested.

P-selectin glycoprotein ligand-1 (PSGL-1) is an important adhesion molecule involved in lymphocyte recruitment into the brain, which represents a crucial step in the pathogenesis of multiple sclerosis (MS). Three hundred twenty-one MS patients and 342 controls were genotyped for the presence of a polymorphism in the PSGL-1 gene, consisting of a variable number of tandem repeats (VNTR) originating three possible alleles: A , B and C , in order to test whether they influence the susceptibility and the course of the disease. No significant differences among allelic frequencies of A , B and C alleles in MS as compared with controls were observed. Stratifying patients according to the course of the disease, a significantly increased frequency of the shortest C allele in PP-MS was found (7.1%), either in comparison with controls ( P = 0.011) or with all other MS patients, who had acute inflammatory attacks at onset and an initial RR form ( P = 0.036). Besides, none of SP-MS patients was a carrier of the C allele and B carriers converted later from RR to SP course as compared with A/A subjects (after 15.8 rather than 8.8 years, P = 0.01). In conclusion, the C allele of the VNTR polymorphism in PSGL-1 is likely to be associated with PP-MS. As this allele has been demonstrated to have a very low efficiency in mediating lymphocyte binding to brain endothelium during attacks, its high frequency in PP-MS could be related to the absence of exacerbations in such patients.

Progranulin has recently attracted attention due to the discovery of mutations in its encoding gene (GRN) in several cases of frontotemporal lobar degeneration, but also for a possible role in inflammatory processes. In adult central nervous system, GRN mRNA is expressed in forebrain, olfactory bulbs and spinal cord. Progranulin cerebrospinal fluid (CSF) levels were evaluated in 55 patients with multiple sclerosis (MS) as well as in 35 subjects with non-inflammatory neurological diseases (NIND), 7 individuals with other inflammatory neurological disease (OIND) and 8 controls (CON), matched for ethnic background, gender and age. No statistically significant differences were found in patients compared with either NIND, OIND or CON (P > 0.05), even stratifying according to disease subtype or gender. A positive correlation between progranulin CSF levels and age was observed in patients (ρ = 0.29, P = 0.03). According to these data, progranulin does not likely play a major role in the pathogenesis of MS.

In this study, we investigated the role of the dipeptidyl-peptidase-6 (DPP6) gene in the etiopathogenesis of progressive forms of multiple sclerosis (PrMS). This gene emerged as a candidate gene in a genome-wide association study (GWAS) performed in an Italian sample of PrMS and controls in which two SNPs located in the gene (rs6956703 and rs11767658) showed evidence of association (nominal p-value10(-4)) (Martinelli-Boneschi et al.) [18]. Moreover, the gene is highly expressed in the central nervous system, and it has been found to be associated with sporadic cases of amyotrophic lateral sclerosis which shares some feature with PrMS.We genotyped 19 SNPs selected using a direct and tagging approach in 244 Italian PrMS and 225 controls, and we measured the expression levels of the gene in 13 PrMS cases and 25 controls.Five out of 19 SNPs were found to be associated with the disease (adjusted p0.05), and they have been tested in an independent sample of 179 primary progressive MS and 198 controls from Northern Europe. None of the SNPs was replicated, but combined analysis confirmed the presence of association for rs2046748 (p=2.5×10(-3),OR=1.82, 95%CI=1.24-2.69).These results, inflated by the limited sample size determined by the rarity of this condition, suggest a possible role of this gene in the susceptibility to PrMS, at least in Southern Europeans. Moreover, DPP6 was over-expressed in PrMS patients compared to controls.

MicroRNA (miRNA)-mediate RNA interference has been identified as a novel mechanism that regulates protein expression. It is recognised that miRNAs play essential roles in the immune system and for correct function in the brain. Moreover, it is now clear that abnormal miRNA expression is a common feature of several diseases involving the immune system including multiple sclerosis (MS). Expression analysis for miR-21, miR-146a and -b, miR-150, miR-155 was carried out in peripheral mononuclear cells (PBMC) from a cohort of 29 MS patients and 19 controls. Subsequently, a case control study for miR-146 rs2910164 variant was performed in an overall population of 346 MS cases and 339 controls. A statistically significant increased expression of miR-21, miR-146a and -b was observed in relapsing remitting (RR)MS patients as compared with controls (1.44 ± 0.13 vs 0.79 ± 0.06, P=0.036; 1.50 ± 0.12 vs 0.84 ± 0.08, P=0.039; 1.54 ± 0.15 vs 0.72 ± 0.08, P=0.001 respectively). On the contrary, no differences were found in the expression levels of both miR-150 and miR-155 in patients as compared with controls (P>0.05). The genetic association study failed to find any differences in the frequencies of rs2910164 between patients and controls. miRNA dysregulation may contribute to the pathogenesis of MS and highlights the possibility to define different disease entities with specific miRNAs profile. © 2011 Elsevier Ireland Ltd.

Glycogen synthase kinase-3 beta (GSK3β) is a ubiquitous kinase that is part of multiple signaling pathways. It has neurotrophic/neuroprotective effects by mediating the actions of neurotrophic molecules in the brain, thus providing neuroprotection through modulation of energy metabolism. Notably, it has been demonstrated that GSK3β is involved in Wnt-beta-catenin signaling, which contributes to the inhibition of myelination and remyelination processes in mammals. Three-hundred nineteen patients with MS and 294 age-matched controls were genotyped by allelic discrimination for four common GSK3β variants (rs2199503, rs9826659, rs334558 and rs6438552) tagging about 100% of GSK-3β variability. A statistically significant increased frequency of the rs334558 GG genotype was observed in patients as compared with controls (25.4% versus 17.7%, P= 0.02; OR:1.58, 95%CI: 1.07-2.34). Stratifying MS patients according to the disease subtype, a statistically significant difference of rs334558 GG frequency was found between Relapsing Remitting (RR), but not Primary Progressive or Secondary MS, and controls (27.0% versus 17.7%, P= 0.01; OR: 1.72, 95%CI: 1.13-2.61). GSK3β rs334558 is a susceptibility factor for MS. As it is located in the promoter region, a possible explanatory mechanism could be an influence of the variant on the gene transcription rate. © 2011 Elsevier Ireland Ltd.

Recently, proteomic analysis in cerebrospinal fluid (CSF) from patients with MS identified four proteins which are present in MS but not in normal human CSF, including SPARCL1, an extracellular matrix-associated protein member of the SPARC family. One hundred eighty-six patients with MS and 185 age-matched controls were genotyped for A/G single nucleotide polymorphism (SNP) in exon 1 (rs1049539), C/G SNP in exon 4 (rs1049544), resulting in a substitution of an aspartate with an histidine, and A/G substitution in the exon 5 (rs1130643), leading to the substitution of alanine with threonine. No significant differences in either allelic or genotypic frequency of the three SNPs were found (P > 0.05), even in stratifying MS patients according to the course of the disease. Stratifying according to gender, a trend towards a decreased frequency of the C/C genotype of the rs1049544 was observed in male patients as compared with male controls (30.2% versus 44.0%; P = 0.217). Despite proteomic studies in CSF from MS patients suggested an important role for SPARCL1 in the development of the disease, SPARCL1 gene does not appear to act as susceptibility factor for MS in the population investigated here. However, the frequency of the C/C genotype of rs1049544 was decreased in male patients, possibly conferring a lower risk of developing MS in male population. Further studies are needed to clarify this issue. © 2007 Elsevier Ireland Ltd. All rights reserved.

A common single nucleotide polymorphism (SNP), consisting in a T → C transition (T-786C) in endothelial nitric oxide synthase (NOS3), has been reported to be associated with vascular pathologies, but no information are available on a possible association with AD. T-786C genotype was determined by polymerase chain reaction–restriction fragment length polymorphisms (PCR–RFLP) assay in an Italian population of 432 AD patients compared with 360 healthy controls, matched for ethnic background, age and gender. Peripheral blood mononuclear cells (PBMC) from 22 subjects (11 AD and 11 controls) carrying different genotypes were isolated. Total RNA was extracted and analyzed by real-time PCR. No significant differences either in allelic or genotypic frequencies of the T-786C polymorphism between AD and normal population were observed, even stratifying AD patients by age at onset, gender, or ApoE status. However, expression of NOS3 in PBMC seems to be influenced by the presence of the C mutated allele, as demonstrated by a tendency towards a decrease in mRNA levels in C carriers, assessed by real-time PCR assay. This effect was observed both in patients and controls, independently from the cognitive impairment, and is likely to be dose-dependent, being mostly evident in CC homozygous. In conclusion, the T-786C SNP does not seem to be a risk factor for sporadic AD, but its presence correlates with a trend toward lower NOS3 expression rate, possibly exerting a beneficial effect in AD by contributing to lower oxidative damage.

Several observations suggest that neurotoxicity in Alzheimer's disease (AD) can be partly attributed to beta-amyloid (Abeta) and senile plaques. Recent work has suggested that the FISH (five SH3 domains) adapter protein and ADAM12 (a disintegrin and metalloprotease) may mediate the neurotoxic effect of Abeta. Both genes are located on chromosome 10, within a region linked to AD (for SH3PXD2A) or nearby (for ADAM12). A recent study reported a statistically significant interaction between 2 variants of these genes (rs3740473 for SH3PXD2A and rs11244787 for ADAM12) with respect to the risk of developing AD. With a view to replicating this observation, we genotyped the two SNPs in four European case-control cohorts of Caucasian origin (1913 cases and 1468 controls) but were unable to confirm the initial results.

Astrocytes associated with beta-amyloid (Abeta) accumulate in senile plaques of Alzheimer's disease (AD). To investigate the biological effects of Abeta/astrocyte interaction, we examined chemokine production by the human astrocytoma cell line U373MG stimulated with Abeta peptides. Northern blot analysis and specific immunoassays demonstrate that Abeta [1-42] and Abeta [25-35] induce mRNA expression and release of monocyte chemotactic protein (MCP)-1 but not of gamma-interferon inducible protein (IP)-10 by U373MG cells. The observation that Abeta induces astrocyte production of the potent microglia chemoattractant MCP-1 contributes to understanding mechanism of damage exerted by Abeta in AD senile plaques.