22 research outputs found
DLX5, FGF8 and the Pin1 isomerase control Np63 protein stability during limb development: a regulatory loop at the basis of the SHFM and EEC congenital malformations
Lime production in the Late Chalcolithic period: the case of Arslantepe (Eastern Anatolia)
Plaster and mortar samples from Arslantepe (Turkey) hold potential to provide unique information about the lime production and adhibition during the Late Chalcolithic period (4th millennium BCE). A multi-analytical approach including polarized light microscopy (PLM), X-ray powder diffraction (XRPD), and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) has been applied to characterize mortar samples from temple C and elite residences dated back to the late Chalcolithic 3–4 (3800–3400 BCE). A marly limestone has been identified as starting raw material for the lime production, probably coming from two different sources (local and brought from a different part of the Malatya plain). Moreover, different aggregate selection and the use of different production techniques were also detected in the samples, which are probably related to the function of the buildings. Evidence of a re-plastering process was also detected in the two elite houses, which probably refers to a routine maintenance process
Mutant prion proteins increase calcium permeability of AMPA receptors, exacerbating excitotoxicity.
Prion protein (PrP) mutations are linked to genetic prion diseases, a class of phenotypically heterogeneous neurodegenerative disorders with invariably fatal outcome. How mutant PrP triggers neurodegeneration is not known. Synaptic dysfunction precedes neuronal loss but it is not clear whether, and through which mechanisms, disruption of synaptic activity ultimately leads to neuronal death. Here we show that mutant PrP impairs the secretory trafficking of AMPA receptors (AMPARs). Specifically, intracellular retention of the GluA2 subunit results in synaptic exposure of GluA2-lacking, calcium-permeable AMPARs, leading to increased calcium permeability and enhanced sensitivity to excitotoxic cell death. Mutant PrPs linked to different genetic prion diseases affect AMPAR trafficking and function in different ways. Our findings identify AMPARs as pathogenic targets in genetic prion diseases, and support the involvement of excitotoxicity in neurodegeneration. They also suggest a mechanistic explanation for how different mutant PrPs may cause distinct disease phenotypes
Correction: Mutant prion proteins increase calcium permeability of AMPA receptors, exacerbating excitotoxicity.
[This corrects the article DOI: 10.1371/journal.ppat.1008654.]
FGF8, c-Abl and p300 participate in a pathway that controls stability and function of the ΔNp63 α
DLX5, FGF8 and the Pin1 isomerase control ΔNp63α protein stability during limb development: a regulatory loop at the basis of the SHFM and EEC congenital malformations.
Ectrodactyly, or Split-Hand/Foot Malformation (SHFM), is a congenital condition characterized by the loss of central rays of hands and feet. The p63 and the DLX5;DLX6 transcription factors, expressed in the embryonic limb buds and ectoderm, are disease genes for these conditions. Mutations of p63 also cause the ectodermal dysplasia-ectrodactyly-cleft lip/palate (EEC) syndrome, comprising SHFM. Ectrodactyly is linked to defects of the apical ectodermal ridge (AER) of the developing limb buds. FGF8 is the key signaling molecule in this process, able to direct proximo-distal growth and patterning of the skeletal primordial of the limbs. In the limb buds of both p63 and Dlx5;Dlx6 murine models of SHFM, the AER is poorly stratified and FGF8 expression is severely reduced. We show here that the FGF8 locus is a downstream target of DLX5 and that FGF8 counteracts Pin1-ΔNp63α interaction. In vivo, lack of Pin1 leads to accumulation of the p63 protein in the embryonic limbs and ectoderm. We show also that ΔNp63α protein stability is negatively regulated by the interaction with the prolyl-isomerase Pin1, via proteasome-mediated degradation; p63 mutant proteins associated with SHFM or EEC syndromes are resistant to Pin1 action. Thus, DLX5, p63, Pin1 and FGF8 participate to the same time- and location-restricted regulatory loop essential for AER stratification, hence for normal patterning and skeletal morphogenesis of the limb buds. These results shed new light on the molecular mechanisms at the basis of the SHFM and EEC limb malformations.JOURNAL ARTICLESCOPUS: ar.jinfo:eu-repo/semantics/publishe
Transgenic Fatal Familial Insomnia Mice Indicate Prion Infectivity-Independent Mechanisms of Pathogenesis and Phenotypic Expression of Disease
<div><p>Fatal familial insomnia (FFI) and a genetic form of Creutzfeldt-Jakob disease (CJD<sup>178</sup>) are clinically different prion disorders linked to the D178N prion protein (PrP) mutation. The disease phenotype is determined by the 129 M/V polymorphism on the mutant allele, which is thought to influence D178N PrP misfolding, leading to the formation of distinctive prion strains with specific neurotoxic properties. However, the mechanism by which misfolded variants of mutant PrP cause different diseases is not known. We generated transgenic (Tg) mice expressing the mouse PrP homolog of the FFI mutation. These mice synthesize a misfolded form of mutant PrP in their brains and develop a neurological illness with severe sleep disruption, highly reminiscent of FFI and different from that of analogously generated Tg(CJD) mice modeling CJD<sup>178</sup>. No prion infectivity was detectable in Tg(FFI) and Tg(CJD) brains by bioassay or protein misfolding cyclic amplification, indicating that mutant PrP has disease-encoding properties that do not depend on its ability to propagate its misfolded conformation. Tg(FFI) and Tg(CJD) neurons have different patterns of intracellular PrP accumulation associated with distinct morphological abnormalities of the endoplasmic reticulum and Golgi, suggesting that mutation-specific alterations of secretory transport may contribute to the disease phenotype.</p></div
Tg(FFI) mice show recognition and spatial working memory impairment.
<p>(A) Performance in the novel object recognition task was expressed as a discrimination index (see Experimental Procedures). Histograms indicate the mean ± SEM of 10 non-Tg/<i>Prnp</i><sup>+/+</sup>, 10 non-Tg/<i>Prnp</i><sup>0/0</sup>, and 8 Tg(FFI-26<sup>+/-</sup>)/<i>Prnp</i><sup>0/0</sup> aged 70 days; F<sub>2,25</sub> = 8.3 p = 0.017 by one-way ANOVA; *p < 0.05, **p < 0.01, Tukey’s post hoc test. (B) Histograms represent the mean ± SEM of total errors in the eight-arm radial maze in the first eight trials during 16 days of training, by the same non-Tg/<i>Prnp</i><sup>0/0</sup> and Tg(FFI-26<sup>+/-</sup>)/<i>Prnp</i><sup>0/0</sup> mice used in A. t<sub>16</sub> = 3.0; p = 0.009; **p < 0.01 by Student’s t test. (C) Values are the mean latency (± SEM) to complete the radial maze. F<sub>15,240</sub> = 19; p = 0.03 by one-way ANOVA for repeated measures. *p < 0.05 by Student’s t test.</p
Tg(FFI) mice show an altered response to sleep deprivation.
<p>Time course of the loss and recovery of time spent in rapid eye movement (REM) (A) and non-rapid eye movement (NREM) (B) sleep, during and after sleep deprivation. Values were from 8 non-Tg/<i>Prnp</i><sup>+/+</sup>, 10 non-Tg/<i>Prnp</i><sup>0/0</sup>, 9 Tg(FFI-26)/<i>Prnp</i><sup>0/0</sup> and 8 Tg(FFI-26)/<i>Prnp</i><sup>+/0</sup>. Mice were kept awake during the first 6 h of the light phase (crosshatched bar) by gentle handling, and allowed to sleep freely in the next 18 h. The black bar indicates the dark portion of the light-dark cycle. REM and NREM sleep were calculated hourly for each animal as the difference between the amount of time spent in a given state (REM or NREM sleep) during and after sleep deprivation, and the amount spent in the corresponding hour during baseline conditions (undisturbed). The hour-by-hour differences were then summed to obtain a cumulative curve. Data (means ± SEM) are presented in 2-h intervals. Single symbols: p < 0.05; double symbols: p < 0.01. *, Tg(FFI-26)/<i>Prnp</i><sup>0/0</sup> vs non-Tg/<i>Prnp</i><sup>0/0</sup>; °, Tg(FFI-26)/<i>Prnp</i><sup>0/0</sup> vs. non-Tg/<i>Prnp</i><sup>+/+</sup>; §, Tg(FFI-26)/<i>Prnp</i><sup>0/0</sup> vs. Tg(FFI-26)/<i>Prnp</i><sup>+/0</sup>; #, Tg(FFI-26)/<i>Prnp</i><sup>+/0</sup> vs. non-Tg/<i>Prnp</i><sup>+/+</sup>. A mixed model analysis of variance for repeated measures was done on 6 h blocks. Between-strains post-hoc comparisons by one-way ANOVA with Bonferroni correction: (panel A) 0–6 h: F<sub>3,101</sub> = 4.98, p = 0.003; 7–12 h: F<sub>3,101</sub> = 5.25, p = 0.002; 13–18 h: F<sub>3,101</sub> = 2.88, p = 0.05; 19–24 h: F<sub>3,101</sub> = 3.30, p = 0.023. (panel B) 0–6 h: F<sub>3,101</sub> = 1.01, p = 0.391; 7–12 h: F<sub>3,101</sub> = 1.78, p = 0.156; 13–18 h: F<sub>3,101</sub> = 3.76, p = 0.013; 19–24 h: F<sub>3,101</sub> = 3.97, p = 0.010.</p