Identification and Functional Characterization of a Novel Mutation in theNKX2-1Gene: Comparison with the Data in the Literature

Background: NKX2-1 mutations have been described in several patients with primary congenital hypothyroidism, respiratory distress, and benign hereditary chorea, which are classical manifestations of the brain-thyroid-lung syndrome (BTLS). Methods: The NKX2-1 gene was sequenced in the members of a Brazilian family with clinical features of BTLS, and a novel monoallelic mutation was identified in the affected patients. We introduced the mutation in an expression vector for the functional characterization by transfection experiments using both thyroidal and lung-specific promoters. Results: The mutation is a deletion of a cytosine at position 834 (ref. sequence NM-003317) (c.493delC) that causes a frameshift with formation of an abnormal protein from amino acid 165 and a premature stop at position 196. The last amino acid of the nuclear localization signal, the whole homeodomain, and the carboxy-terminus of NKX2-1 are all missing in the mutant protein, which has a premature stop codon at position 196 (p.Arg165Glyfs*32). The p.Arg165Glyfs*32 mutant does not bind DNA, and it is unable to transactivate the thyroglobulin (Tg) and the surfactant protein-C (SP-C) promoters. Interestingly, a dose-dependent dominant negative effect of the p.Arg165Glyfs*32 was demonstrated only on the Tg promoter, but not on the SP-C promoter. This effect was also noticed when the mutation was tested in presence of PAX8 or cofactors that synergize with NKX2-1 (P300 and TAZ). The functional effect was also compared with the data present in the literature and demonstrated that, so far, it is very difficult to establish a specific correlation among NKX2-1 mutations, their functional consequence, and the clinical phenotype of affected patients, thus suggesting that the detailed mechanisms of transcriptional regulation still remain unclear. Conclusions: We describe a novel NKX2-1 mutation and demonstrate that haploinsufficiency may not be the only explanation for BTLS. Our results indicate that NKX2-1 activity is also finely regulated in a tissue-specific manner, and additional studies are required to better understand the complexities of genotype-phenotype correlations in the NKX2-1 deficiency syndrome

Amyloid and tau cerebrospinal fluid biomarkers in HIV infection

<p>Abstract</p> <p>Background</p> <p>Because of the emerging intersections of HIV infection and Alzheimer's disease, we examined cerebrospinal fluid (CSF) biomarkers related of amyloid and tau metabolism in HIV-infected patients.</p> <p>Methods</p> <p>In this cross-sectional study we measured soluble amyloid precursor proteins alpha and beta (sAPPα and sAPPβ), amyloid beta fragment 1-42 (Aβ_1-42), and total and hyperphosphorylated tau (t-tau and p-tau) in CSF of 86 HIV-infected (HIV+) subjects, including 21 with AIDS dementia complex (ADC), 25 with central nervous system (CNS) opportunistic infections and 40 without neurological symptoms and signs. We also measured these CSF biomarkers in 64 uninfected (HIV-) subjects, including 21 with Alzheimer's disease, and both younger and older controls without neurological disease.</p> <p>Results</p> <p>CSF sAPPα and sAPPβ concentrations were highly correlated and reduced in patients with ADC and opportunistic infections compared to the other groups. The opportunistic infection group but not the ADC patients had lower CSF Aβ_1-42in comparison to the other HIV+ subjects. CSF t-tau levels were high in some ADC patients, but did not differ significantly from the HIV+ neuroasymptomatic group, while CSF p-tau was not increased in any of the HIV+ groups. Together, CSF amyloid and tau markers segregated the ADC patients from both HIV+ and HIV- neuroasymptomatics and from Alzheimer's disease patients, but not from those with opportunistic infections.</p> <p>Conclusions</p> <p>Parallel reductions of CSF sAPPα and sAPPβ in ADC and CNS opportunistic infections suggest an effect of CNS immune activation or inflammation on neuronal amyloid synthesis or processing. Elevation of CSF t-tau in some ADC and CNS infection patients without concomitant increase in p-tau indicates neural injury without preferential accumulation of hyperphosphorylated tau as found in Alzheimer's disease. These biomarker changes define pathogenetic pathways to brain injury in ADC that differ from those of Alzheimer's disease.</p

Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer's disease

We sought to identify new susceptibility loci for Alzheimer's disease through a staged association study (GERAD+) and by testing suggestive loci reported by the Alzheimer's Disease Genetic Consortium (ADGC) in a companion paper. We undertook a combined analysis of four genome-wide association datasets (stage 1) and identified ten newly associated variants with P ≤ 1 × 10−5. We tested these variants for association in an independent sample (stage 2). Three SNPs at two loci replicated and showed evidence for association in a further sample (stage 3). Meta-analyses of all data provided compelling evidence that ABCA7 (rs3764650, meta P = 4.5 × 10−17; including ADGC data, meta P = 5.0 × 10−21) and the MS4A gene cluster (rs610932, meta P = 1.8 × 10−14; including ADGC data, meta P = 1.2 × 10−16) are new Alzheimer's disease susceptibility loci. We also found independent evidence for association for three loci reported by the ADGC, which, when combined, showed genome-wide significance: CD2AP (GERAD+, P = 8.0 × 10−4; including ADGC data, meta P = 8.6 × 10−9), CD33 (GERAD+, P = 2.2 × 10−4; including ADGC data, meta P = 1.6 × 10−9) and EPHA1 (GERAD+, P = 3.4 × 10−4; including ADGC data, meta P = 6.0 × 10−10)

CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research

The PED/PEA-15 diabetogene as a potential thiazolidinedione target in type 2 diabetes treatment

The phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes (PED/PEA-15) gene is over-expressed in tissues from individuals with type 2 diabetes. In cultured cells and in vivo, ped/pea-15 over-expression impairs insulin activation of protein kinase C zeta (PKCζ) and glucose disposal. Indeed, transgenic mice ubiquitously over-expressing ped/pea-15 feature impaired glucose tolerance and insulin resistance. However, it is still unknown how PED/PEA-15 gene expression is regulated. Recently, we have obtained evidence that Thiazolidinediones (TZDs), a class of peroxisome proliferator-activated receptor gamma (PPARγ) ligands, repress ped/pea-15 expression both at mRNA and protein levels. PPARγ is a member of the nuclear hormone receptor super-family that modulates gene expression upon ligand binding. Ligand-mediated activation of PPARγ has been linked to glucose homeostasis, cellular differentiation, apoptosis and anti-inflammatory responses. The aim of this work was to study whether and how TZD-activated PPARγ may exert its action on ped/pea-15 expression. In L6 skeletal muscle cells, rosiglitazone (RGTZ) decreased both ped/pea-15 mRNA and protein levels. This was paralleled by the RGTZ-dependent reduction of PKCα activation and a consequent increase of PKCζ activity. Consistent with the in vitro data, muscle tissue from control mice showed a 40% decrease of ped/pea-15 protein levels upon 10 days of treatment with RGTZ. HeLa cells treated with TPA, the prototypical AP1 activator, showed an increase in PED/PEA-15 mRNA levels. TPA induced also the activation of PED/PEA-15 promoter activity measured by luciferase assays. Interestingly, TPA effect was suppressed by RGTZ. EMSA and ChIP assays revealed that TPA caused an increased binding to the CRE-like site (a putative AP1 binding site) on the PED/PEA-15 promoter, and this binding was reduced by RGTZ. Since PPARγ activation by TZDs blocks AP1-mediated gene transcription, we hypothesized that PPARγ transrepression of the PED/PEA-15 gene could be due to a competition for limiting amounts of co-activators present in the cell. Indeed, the suppressive effect of rosiglitazone on PED/PEA-15 gene expression was blocked by over-expressing a dominant negative form of PPARγ, which lacks the ability to recruit the coactivator CBP/p300 (CREB-binding protein). The over-expression of p300 did not rescue the cells from the suppressive effect of PPARγ on PED/PEA-15 promoter activity, suggesting that PPARγ-mediated repression of AP1 transcriptional activity occurs in a CBP/p300-independent manner. Taken together, these results indicate that regulation through the CRE-like site on PED/PEA-15 promoter induces PED/PEA-15 transcription. This effect was blocked by treatment with TZDs. Finally, the results of this study identified PED/PEA-15 gene as a potential target for TZDs therapeutic action