Dosage-dependent copy number gains in E2f1 and E2f3 drive hepatocellular carcinoma.

Disruption of the retinoblastoma (RB) tumor suppressor pathway, either through genetic mutation of upstream regulatory components or mutation of RB1 itself, is believed to be a required event in cancer. However, genetic alterations in the RB-regulated E2F family of transcription factors are infrequent, casting doubt on a direct role for E2Fs in driving cancer. In this work, a mutation analysis of human cancer revealed subtle but impactful copy number gains in E2F1 and E2F3 in hepatocellular carcinoma (HCC). Using a series of loss- and gain-of-function alleles to dial E2F transcriptional output, we have shown that copy number gains in E2f1 or E2f3b resulted in dosage-dependent spontaneous HCC in mice without the involvement of additional organs. Conversely, germ-line loss of E2f1 or E2f3b, but not E2f3a, protected mice against HCC. Combinatorial mapping of chromatin occupancy and transcriptome profiling identified an E2F1- and E2F3B-driven transcriptional program that was associated with development and progression of HCC. These findings demonstrate a direct and cell-autonomous role for E2F activators in human cancer.

C9ORF72 repeat expansion not detected in patients with multiple sclerosis.

A hexanucleotide repeat expansion in the chromosome 9 Open Reading Frame 72 gene (C9ORF72) has recently been reported to be cause of familial amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Nevertheless, in the last few years this mutation has been found to be associated with heterogeneous phenotypes, including multiple sclerosis (MS) in concurrence with amyotrophic lateral sclerosis. In this study, we sought to evaluate the presence of the C9ORF72 repeat expansion in a cohort consisting of 314 patients with MS and 222 control subjects. No pathogenic expansion was found in MS and control populations, suggesting that C9ORF72 does not play a major role in MS pathogenesis.

Decreased circulating miRNA levels in patients with primary progressive multiple sclerosis.

Emerging evidence underlines the importance of micro(mi)RNAs in the pathogenesis of multiple sclerosis (MS). Free-circulating miRNAs were investigated in serum from MS patients compared to controls. Statistically significant decreased levels of miR-15b, miR-23a and miR-223 were observed in MS patients (p < 0.05). Results were validated and replicated in two further independent MS populations. A direct correlation between miRNA levels and the EDSS score was determined in PPMS (p < 0.007). The generalized trend toward miRNA down-regulation could result in over-expression of target genes involved in disease pathogenesis. Circulating miRNA profiling could thus represent a new avenue to identify easily detectable disease biomarkers.

An emerging role for long non-coding RNA dysregulation in neurological disorders.

A novel class of transcripts, long non coding RNAs (lncRNAs), has recently emerged as key players in several biological processes, including dosage compensation, genomic imprinting, chromatin regulation, embryonic development and segmentation, stem cell pluripotency, cell fate determination and potentially many other biological processes, which still are to be elucidated. LncRNAs are pervasively transcribed in the genome and several lines of evidence correlate dysregulation of different lncRNAs to human diseases including neurological disorders. Although their mechanisms of action are yet to be fully elucidated, evidence suggests lncRNA contributions to the pathogenesis of a number of diseases. In this review, the current state of knowledge linking lncRNAs to different neurological disorders is discussed and potential future directions are considered.

The role of the innate immune system in Alzheimer's disease and frontotemporal lobar degeneration: an eye on microglia.

In the last few years, genetic and biomolecular mechanisms at the basis of Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD) have been unraveled. A key role is played by microglia, which represent the immune effector cells in the central nervous system (CNS). They are extremely sensitive to the environmental changes in the brain and are activated in response to several pathologic events within the CNS, including altered neuronal function, infection, injury, and inflammation. While short-term microglial activity has generally a neuroprotective role, chronic activation has been implicated in the pathogenesis of neurodegenerative disorders, including AD and FTLD. In this framework, the purpose of this review is to give an overview of clinical features, genetics, and novel discoveries on biomolecular pathogenic mechanisms at the basis of these two neurodegenerative diseases and to outline current evidence regarding the role played by activated microglia in their pathogenesis.

GRN Thr272fs clinical heterogeneity: a case with atypical late onset presenting with a dementia with Lewy bodies phenotype.

We describe a case of late onset frontotemporal dementia carrying the g.1977_1980 delCACT (Thr272fs) mutation in progranulin (GRN) gene, characterized by a positive family history for dementia and a clinical phenotype resembling dementia with Lewy bodies. Symptoms included prominent visuospatial impairment, complex misidentification syndrome, visual zooptic hallucinations, hypersomnia, mental fluctuations, and signs of parkinsonism. The patient showed normal cerebrospinal fluid levels of amyloid-ß, tau, and Ptau biomarkers, an asymmetric pattern of cerebral atrophy and hypoperfusion, and parietal hypometabolism. A major contributing factor to the diagnosis was the testing of plasmatic progranulin levels (extremely low), which prompted us to sequence GRN.

Expression and Genetic Analysis of MicroRNAs Involved in Multiple Sclerosis.

Evidence underlines the importance of microRNAs (miRNAs) in the pathogenesis of multiple sclerosis (MS). Based on the fact that miRNAs are present in human biological fluids, we previously showed that miR-223, miR-23a and miR-15b levels were downregulated in the sera of MS patients versus controls. Here, the expression levels of these candidate miRNAs were determined in peripheral blood mononuclear cells (PBMCs) and the serum of MS patients, in addition to three genotyped single nucleotide polymorphisms (SNPs). Mapping in the genomic regions of miR-223, miR-23a and miR-15b genes, 399 cases and 420 controls were tested. Expression levels of miR-223 and miR-23a were altered in PBMCs from MS patients versus controls. Conversely, there were no differences in the expression levels of miR-15b. A significantly decreased genotypic frequency of miR-223 rs1044165 T/T genotype was observed in MS patients. Moreover, the allelic frequency of miR-23a rs3745453 C allele was significantly increased in patients versus controls. In contrast, there were no differences in the distribution of miR-15b SNP. In conclusion, our results suggest that miR-223 and miR-23a could play a role in the pathogenesis of MS. Moreover, miR-223 rs1044165 polymorphism likely acts as a protective factor, while miR-23a rs3745453 variant seems to act as a risk factor for MS.

Expression of the transcription factor Sp1 and its regulatory hsa-miR-29b in peripheral blood mononuclear cells from patients with Alzheimer's disease.

Altered gene expression occurs in central nervous system disorders, including Alzheimer's disease (AD). Transcription factor Sp1 (specificity protein 1) can regulate the expression of several AD-related proteins, including amyloid-ß protein precursor and tau. Sp1 is regulated by oxidative stress, and Sp1 mRNA was found to be upregulated in AD cortex and hippocampus. The distribution of three single nucleotide polymorphisms (SNPs), including rs7300593, rs17695156, and rs12821290, covering 100% Sp1 genetic variability, has been determined in a population of 393 AD patients as compared with 412 controls. In addition, expression analysis of Sp1 and its regulatory microRNAs (hsa-miR-29b and hsa-miR-375) has been performed in peripheral blood mononuclear cells (PBMCs), together with Sp1 protein analysis. No differences in all three SNP distributions were observed in AD patients as compared with controls. Stratifying according to gender, a significantly decreased frequency of Sp1 rs17695156 T allele was observed in male patients versus male controls. Significantly increased Sp1 relative expression levels were observed in PBMCs from AD patients as compared with controls. Western blot analysis paralleled mRNA increase in AD patients versus controls and correlated positively with Sp1 mRNA levels. Significantly decreased relative expression levels of hsa-miR-29b, but not of hsa-miR-375, were observed in AD patients versus controls and correlated negatively with Sp1 mRNA levels. According to these results, Sp1 and its regulatory hsa-miR-29b are deregulated in AD patients, possibly leading to aberrant production of downstream target genes involved in the pathogenesis. Moreover, Sp1 rs176951056 T allele is likely a protective factor in the male population.

MicroRNAs as active players in the pathogenesis of multiple sclerosis.

MicroRNAs (miRNAs) are a recently discovered group of small noncoding RNAs that regulate gene expression post-transcriptionally. They are highly expressed in cells of the immune system, as well as in the central nervous system, and they are deregulated in various neurological disorders. Emerging evidence underlines an involvement of miRNAs in the pathogenesis of Multiple Sclerosis (MS). A number of miRNAs have been found to be dysregulated in blood cells from MS patients, in brain lesions, as well as in biological fluids such as serum and plasma. Despite miRNA altered expression likely showing a high tissue specificity, some profile similarities could be observed for certain miRNAs such as miR-326-such as upregulation in both active lesions and blood-though not for others such as miR-323, which demonstrated upregulation in whole blood, active brain lesions, and T-reg cells, but not in the serum of MS patients. In this review, the possible role of miRNAs in MS pathogenesis will be discussed according to all the available literature, with a particular emphasis on the possibility of considering extracellular miRNAs as a new source for both biomarker identification and therapeutic target discovery.

Early onset behavioral variant frontotemporal dementia due to the C9ORF72 hexanucleotide repeat expansion: psychiatric clinical presentations.

A hexanucleotide repeat expansion in the first intron of C9ORF72 has been shown to be responsible for a high number of familial cases of amyotrophic lateral sclerosis or frontotemporal lobar degeneration with or without concomitant motor neuron disease phenotype and TDP-43 based pathology. Here, we report on three cases carrying the hexanucleotide repeat expansion with an atypical presentation consisting in the development of psychiatric symptoms. Patient #1, a 53 year old man with positive family history for dementia, presented with mood deflection, characterized by apathy, social withdraw, and irritability in the last two years. He was diagnosed with "mild cognitive impairment due to depressive syndrome" six months later and subsequently with Alzheimer's disease. Patient #2, a woman with positive family history for dementia, developed behavioral disturbances, aggressiveness, and swearing at 57 years of age. Patient #3 presented, in the absence of brain atrophy, with mystical delirium with auditory hallucinations at 44 years of age, and did not present neurological symptoms over a 7-year follow up. The description of these cases underlines that the hexanucleotide repeat expansion in chromosome 9 could be associated with early onset psychiatric presentations.

Genetics and expression analysis of the specificity protein 4 gene (SP4) in patients with Alzheimer's disease and frontotemporal lobar degeneration.

Transcription factor Sp4 (Specificity protein 4) levels are increased in the brain of patients with Alzheimer's disease (AD), and Sp4 colocalizes with neurofibrillary tangles. Moreover, SP4 is a susceptibility gene for bipolar disorder and schizophrenia, which share many clinical features with frontotemporal lobar degeneration (FTLD). The distribution of three tagging single nucleotide polymorphisms(SNPs)-rs9639379, rs10272006, and rs6461569-has been determined in a population of 352 patients diagnosed clinically with AD, 290 patients with FTLD, and 341 age-matched controls. Expression analysis of SP4 was performed in peripheral blood mononuclear cells (PBMC). No significant differences in either allelic or genotypic frequency of the three SNPs were found (p > 0.05), even stratifying according to gender and to the apolipoprotein E status. Significantly increased SP4 relative expression levels were observed in PBMC from patients with AD as compared with controls (7.132 ± 1.301 versus 3.396 ± 0.829, p < 0.050) and a similar trend was shown in patients with FTLD compared with controls (6.525 ± 1.500 versus 3.396 ± 0.829, p = 0.073). According to these results, SP4 gene does not act as a susceptibility factor either for AD or FTLD. However, Sp4 mRNA levels are upregulated in patients, possibly resulting in an aberrant expression of downstream target genes involved in the pathogenesis of both diseases.

Progranulin gene variability and plasma levels in bipolar disorder and schizophrenia.

Basing on the assumption that frontotemporal lobar degeneration (FTLD), schizophrenia and bipolar disorder (BPD) might share common aetiological mechanisms, we analyzed genetic variation in the FTLD risk gene progranulin (GRN) in a German population of patients with schizophrenia (n = 271) or BPD (n = 237) as compared with 574 age-, gender- and ethnicity-matched controls. Furthermore, we measured plasma progranulin levels in 26 German BPD patients as well as in 61 Italian BPD patients and 29 matched controls.A significantly decreased allelic frequency of the minor versus the wild-type allele was observed for rs2879096 (23.2 versus 34.2%, P<0.001, OR:0.63, 95%CI:0.49-0.80), rs4792938 (30.7 versus 39.7%, P = 0.005, OR: 0.70, 95%CI: 0.55-0.89) and rs5848 (30.3 versus 36.8, P = 0.007, OR: 0.71, 95%CI: 0.56-0.91). Mean±SEM progranulin plasma levels were significantly decreased in BPD patients, either Germans or Italians, as compared with controls (89.69±3.97 and 116.14±5.80 ng/ml, respectively, versus 180.81±18.39 ng/ml P<0.001) and were not correlated with age.In conclusion, GRN variability decreases the risk to develop BPD and schizophrenia, and progranulin plasma levels are significantly lower in BPD patients than in controls. Nevertheless, a larger replication analysis would be needed to confirm these preliminary results.

MicroRNA and mRNA expression profile screening in multiple sclerosis patients to unravel novel pathogenic steps and identify potential biomarkers.

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 and genetic analysis of miRNAs involved in CD4+ cell activation in patients with multiple sclerosis.

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.

Role of OLR1 and its regulating hsa-miR369-3p in Alzheimer's disease: genetics and expression analysis.

The oxidized LDL receptor 1 gene (OLR1) rs1050283 single nucleotide polymorphism (SNP) has been previously shown to be associated with Alzheimer's disease (AD). An association analysis of OLR1 was carried out in a population of 443 patients with AD as compared with 393 age-matched controls. In addition, an expression analysis of OLR1 and its regulatory hsa-miR369-3p was performed in peripheral mononuclear blood cells (PBMC) from 20 patients and 15 controls. Logistic regression analysis, adjusted for gender and apolipoprotein E (ApoE) status, showed a statistically significant association of OLR1 rs1050283 under the assumption of a dominant model (CC and CT individuals versus TT: p = 0.014, OR: 1.50, 95%CI: 1.08-2.08) and a genotypic model (TC versus TT: p = 0.002, OR: 1.61, 95%CI: 1.14-2.26). No significant differences in OLR1 expression was observed between patients and controls (p > 0.05). However, stratifying patients according to the rs1050283 status, significantly decreased relative PBMC expression levels of OLR1 were observed in carriers of CC+CT genotypes as compared with TT carriers (0.13 ± 0.013 versus 0.46 ± 0.028, p = 0.022), whereas no differences in relative expression levels of the hsa-miR369-3p were observed (p > 0.05). The effect observed was not due to the presence of the ApoE ε4 allele. The OLR1 rs1050283 SNP likely acts as a risk factor for sporadic AD. The presence of at least one C allele is associated with a decreased expression of OLR1 mRNA in the absence of hsa-miR369-3p de-regulation, suggesting that the presence of the polymorphic allele influences the binding of hsa-miR369-3p to its 3'UTR consensus sequence. Nevertheless, the limited power of the study requires further investigations with a larger sample size.

A novel MAPT mutation associated with the clinical phenotype of progressive nonfluent aphasia.

A number of mutations in microtubule associated protein tau gene (MAPT), causing frontotemporal lobar degeneration (FTLD) with tau pathology, are located in the four-repeated microtubule (MT) binding domains and affect the ability of tau to bind MTs. Here, we describe a novel variant lying in the second MT domain, found in a female patient diagnosed clinically with progressive nonfluent aphasia (PNFA), with a positive family history for dementia. At 65 years, she started developing progressive language deficits, characterized by expression difficulties and word coordination impairment. She came to our attention at 67 years. Her MMSE score was 22/30. A Brain CT scan showed mild diffuse cortical atrophy, ventricles' asymmetry (left > right), and very mild signs of chronic vasculopathy. Cerebrospinal fluid analysis showed normal amyloid-ß42, tau, and P-tau levels. She was diagnosed with PNFA according to current diagnostic criteria. A novel exon 10 MAPT variant was identified (g.123798G > A), which leads to an amino acidic change (p.Gly304Ser) in the second MT microtubule binding domain. In silico analysis predicted that this variant is damaging on protein structure and function. Additional 168 FTLD patients and 503 controls screened (1342 chromosomes) did not carry the variant, suggesting that it is a mutation rather than a polymorphism. The amino acid change likely compromises the ability of tau to properly regulate the dynamic behavior of microtubules.

GSK3ß genetic variability in patients with Multiple Sclerosis.

Glycogen synthase kinase-3 beta (GSK3ß) 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 GSK3ß 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 GSK3ß variants (rs2199503, rs9826659, rs334558 and rs6438552) tagging about 100% of GSK-3ß 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). GSK3ß 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.

BAG1 is a protective factor for sporadic frontotemporal lobar degeneration but not for Alzheimer's disease.

BCL2-associated athanogene 1 (BAG1) is an anti-apoptotic factor that interacts with tau and regulates its proteasomal degradation. A significant increase of the BAG-1M isoform was found in Alzheimer's disease (AD) brains, and the protein co-localized with tau and amyloid. We carried out an association study of BAG1 in a population of 291 patients clinically diagnosed with frontotemporal lobar degeneration (FTLD), none of whom was a carrier of mutations in progranulin or microtubule associated protein tau genes and 374 with AD as compared with 314 age- and gender-matched controls. In addition, another candidate named Chromatin-modifying protein 5 (CHMP5) and located in the same linkage disequilibrium block, has been included in this study. The distribution of the two single nucleotide polymorphism (SNPs), rs844239 in CHMP5 and rs706118 in BAG1, covering 100% gene variability, were determined. A statistically significant decreased allelic frequency of the BAG-1 rs706118 SNP was observed in patients with FTLD as compared with controls (16.7 versus 23.9%; p = 0.007, OR: 0.35, CI: 0.25-0.50), whereas allelic frequency of the SNP in patients with AD was similar to controls (24.3%, p > 0.05). Conversely, no significant association was found as regards CHMP5 rs844239. Stratifying according to gender, no differences were observed. BAG-1 rs706118 SNP likely acts as protective factor for sporadic FTLD, but not for AD, suggesting its specific role in a pathogenic event in FTLD. Nevertheless, a replication study would be needed to confirm these preliminary results.

Effects of simulated altitude (normobaric hypoxia) on cardiorespiratory parameters and circulating endothelial precursors in healthy subjects.

BACKGROUND: Circulating Endothelial Precursors (PB-EPCs) are involved in the maintenance of the endothelial compartment being promptly mobilized after injuries of the vascular endothelium, but the effects of a brief normobaric hypoxia on PB-EPCs in healthy subjects are scarcely studied. METHODS: Clinical and molecular parameters were investigated in healthy subjects (n = 8) in basal conditions (T0) and after 1 h of normobaric hypoxia (T1), with Inspiratory Fraction of Oxygen set at 11.2% simulating 4850 mt of altitude. Blood samples were obtained at T0 and T1, as well as 7 days after hypoxia (T2). RESULTS: In all studied subjects we observed a prompt and significant increase in PB-EPCs, with a return to basal value at T2. The induction of hypoxia was confirmed by Alveolar Oxygen Partial Pressure (PAO2) and Spot Oxygen Saturation decreases. Heart rate increased, but arterial pressure and respiratory response were unaffected. The change in PB-EPCs percent from T0 to T1 was inversely related to PAO2 at T1. Rapid (T1) increases in serum levels of hepatocyte growth factor and erythropoietin, as well as in cellular PB-EPCs-expression of Hypoxia Inducible Factor-1alpha were observed. CONCLUSION: In conclusion, the endothelial compartment seems quite responsive to standardized brief hypoxia, possibly important for PB-EPCs activation and recruitment.

c-Src/histone deacetylase 3 interaction is crucial for hepatocyte growth factor dependent decrease of CXCR4 expression in highly invasive breast tumor cells.

Hepatocyte growth factor (HGF), a cytokine of tumor microenvironment, exerts opposite effects on CXCR4 expression in MCF-7 (low invasive) and MDA-MB231 (highly invasive) breast carcinoma cells, and here, we show that completely different molecular mechanisms downstream of c-Src activation were involved. As experimental models, we used cells transfected with two CXCR4 promoter constructs and treated with HGF or cotransfected with c-Src wild-type (Srcwt) expression vector; phospho-c-Src formation was enhanced in both cell lines. In MCF-7 cells, consistent with activations of CXCR4Luc constructs after HGF treatment and Srcwt expression, Ets1 and nuclear factor-kappaB (NF-kappaB) transcription factors were activated. In contrast, in MDA-MB231 cells, CXCR4Luc construct, Ets1 and NF-kappaB activities decreased. The divergence point seemed to be downstream of HGF/c-Src and consisted in the interaction between c-Src and the substrate histone deacetylase 3 (HDAC3). Only in MDA-MB231 cells, HDAC3 level was enhanced in membranes and nuclei 30 min after HGF and colocalized/coimmunoprecipitated with phospho-c-Src and phosphotyrosine. Thus, the CXCR4 induction by HGF in MCF-7 cells required NF-kappaB and Ets1 activations, downstream of phosphoinositide-3-kinase/Akt, whereas in HGF-treated MDA-MB231 cells, HDAC3 activation via c-Src probably caused a reduction of transcription factor activities, such as that of NF-kappaB. These results indicate possible roles of HGF in invasive growth of breast carcinomas. By enhancing CXCR4 in low invasive tumor cells, HGF probably favors their homing to secondary sites, whereas by suppressing CXCR4 in highly invasive cells, HGF might participate to retain them in the metastatic sites.