<i>C-elegans</i> model identifies genetic modifiers of alpha-synuclein inclusion formation during aging

Inclusions in the brain containing alpha-synuclein are the pathological hallmark of Parkinson's disease, but how these inclusions are formed and how this links to disease is poorly understood. We have developed a &lt;i&gt;C-elegans&lt;/i&gt; model that makes it possible to monitor, in living animals, the formation of alpha-synuclein inclusions. In worms of old age, inclusions contain aggregated alpha-synuclein, resembling a critical pathological feature. We used genome-wide RNA interference to identify processes involved in inclusion formation, and identified 80 genes that, when knocked down, resulted in a premature increase in the number of inclusions. Quality control and vesicle-trafficking genes expressed in the ER/Golgi complex and vesicular compartments were overrepresented, indicating a specific role for these processes in alpha-synuclein inclusion formation. Suppressors include aging-associated genes, such as sir-2.1/SIRT1 and lagr-1/LASS2. Altogether, our data suggest a link between alpha-synuclein inclusion formation and cellular aging, likely through an endomembrane-related mechanism. The processes and genes identified here present a framework for further study of the disease mechanism and provide candidate susceptibility genes and drug targets for Parkinson's disease and other alpha-synuclein related disorders

Site-specific perturbations of alpha-synuclein fibril structure by the Parkinson's disease associated mutations A53T and E46K.

PMCID: PMC3591419This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Parkinson's disease (PD) is pathologically characterized by the presence of Lewy bodies (LBs) in dopaminergic neurons of the substantia nigra. These intracellular inclusions are largely composed of misfolded α-synuclein (AS), a neuronal protein that is abundant in the vertebrate brain. Point mutations in AS are associated with rare, early-onset forms of PD, although aggregation of the wild-type (WT) protein is observed in the more common sporadic forms of the disease. Here, we employed multidimensional solid-state NMR experiments to assess A53T and E46K mutant fibrils, in comparison to our recent description of WT AS fibrils. We made de novo chemical shift assignments for the mutants, and used these chemical shifts to empirically determine secondary structures. We observe significant perturbations in secondary structure throughout the fibril core for the E46K fibril, while the A53T fibril exhibits more localized perturbations near the mutation site. Overall, these results demonstrate that the secondary structure of A53T has some small differences from the WT and the secondary structure of E46K has significant differences, which may alter the overall structural arrangement of the fibrils

Generalized model for dynamic percolation

We study the dynamics of a carrier, which performs a biased motion under the influence of an external field E, in an environment which is modeled by dynamic percolation and created by hard-core particles. The particles move randomly on a simple cubic lattice, constrained by hard-core exclusion, and they spontaneously annihilate and re-appear at some prescribed rates. Using decoupling of the third-order correlation functions into the product of the pairwise carrier-particle correlations we determine the density profiles of the "environment" particles, as seen from the stationary moving carrier, and calculate its terminal velocity, V_c, as the function of the applied field and other system parameters. We find that for sufficiently small driving forces the force exerted on the carrier by the "environment" particles shows a viscous-like behavior. An analog Stokes formula for such dynamic percolative environments and the corresponding friction coefficient are derived. We show that the density profile of the environment particles is strongly inhomogeneous: In front of the stationary moving carrier the density is higher than the average density, $\rho_s$, and approaches the average value as an exponential function of the distance from the carrier. Past the carrier the local density is lower than $\rho_s$ and the relaxation towards $\rho_s$ may proceed differently depending on whether the particles number is or is not explicitly conserved.Comment: Latex, 32 pages, 4 ps-figures, submitted to PR

Growth charts for children with Ellis–van Creveld syndrome

Ellis–van Creveld (EvC) syndrome is a congenital malformation syndrome with marked growth retardation. In this study, specific growth charts for EvC patients were derived to allow better follow-up of growth and earlier detection of growth patterns unusual for EvC. With the use of 235 observations of 101 EvC patients (49 males, 52 females), growth charts for males and females from 0 to 20 years of age were derived. Longitudinal and cross-sectional data were collected from an earlier review of growth data in EvC, a database of EvC patients, and from recent literature. To model the growth charts, the GAMLSS package for the R statistical program was used. Height of EvC patients was compared to healthy children using Dutch growth charts. Data are presented both on a scale for age and on a scale for the square root of age. Compared to healthy Dutch children, mean height standard deviation score values for male and female EvC patients were −3.1 and −3.0, respectively. The present growth charts should be useful in the follow-up of EvC patients. Most importantly, early detection of growth hormone deficiency, known to occur in EvC, will be facilitated

Molecular and clinical analysis of Ellis-van Creveld syndrome in the United Arab Emirates

<p>Abstract</p> <p>Background</p> <p>Ellis-van Creveld (EvC) syndrome is an autosomal recessive chondrodysplastic condition with clinical manifestations that include short-limbs and ribs, postaxial polydactyly and dysplastic nails and teeth. In about two thirds of patients, mutations in either <it>EVC </it>or <it>EVC2 </it>genes have been found to be the underlying cause.</p> <p>Methods</p> <p>In this paper, we describe the molecular (DNA sequencing) and clinical analysis of six children diagnosed with EvC from four different families from the United Arab Emirates (UAE).</p> <p>Results</p> <p>All the children had the common clinical and radiological features of this syndrome. However, DNA sequence analysis of the genes shown to be involved (<it>EVC </it>and <it>EVC2</it>) revealed a novel splice site mutation (c.2047-1G>T) in intron 13 of <it>EVC2 </it>gene in one family. In addition, we confirm previous mutational analyses that showed a truncating mutation in exon 13 of <it>EVC </it>gene (c.1813C>T; p.Q605X) in the second family and a single nucleotide deletion (c.981delG; p.K327<it>fs</it>) in exon 8 of <it>EVC2 </it>gene in the third family. No mutations in the exons, splice sites or the promoter regions of either gene have been found in the index case of the fourth family who exhibited "EvC-like" features.</p> <p>Conclusions</p> <p>Given the small population size of UAE, our data illustrates further the molecular heterogeneity observed in EvC patients and excludes the possibility of a common founder effect for this condition in the UAE reflecting the current ethnic diversity of the country.</p

Improved Immunodetection of Endogenous α-Synuclein

α-Synuclein is a key molecule in understanding the pathogenesis of neurodegenerative α-synucleinopathies such as Parkinson's disease. Despite extensive research, however, its precise function remains unclear partly because of a difficulty in immunoblotting detection of endogenous α-synuclein. This difficulty has largely restricted the progress for α-synucleinopathy research. Here, we report that α-synuclein monomers tend to easily detach from blotted membranes, resulting in no or very poor detection. To prevent this detachment, a mild fixation of blotted membranes with paraformaldehyde was applied to the immunoblotting method. Amazingly, this fixation led to clear and strong detection of endogenous α-synuclein, which has been undetectable by a conventional immunoblotting method. Specifically, we were able to detect endogenous α-synuclein in various human cell lines, including SH-SY5Y, HEK293, HL60, HeLa, K562, A375, and Daoy, and a mouse cell line B16 as well as in several mouse tissues such as the spleen and kidney. Moreover, it should be noted that we could clearly detect endogenous α-synuclein phosphorylated at Ser-129 in several human cell lines. Thus, in some tissues and cultured cells, endogenous α-synuclein becomes easily detectable by simply fixing the blotted membranes. This improved immunoblotting method will allow us to detect previously undetectable endogenous α-synuclein, thereby facilitating α-synuclein research

TOM40 Mediates Mitochondrial Dysfunction Induced by α-Synuclein Accumulation in Parkinson's Disease.

Alpha-synuclein (α-Syn) accumulation/aggregation and mitochondrial dysfunction play prominent roles in the pathology of Parkinson's disease. We have previously shown that postmortem human dopaminergic neurons from PD brains accumulate high levels of mitochondrial DNA (mtDNA) deletions. We now addressed the question, whether alterations in a component of the mitochondrial import machinery -TOM40- might contribute to the mitochondrial dysfunction and damage in PD. For this purpose, we studied levels of TOM40, mtDNA deletions, oxidative damage, energy production, and complexes of the respiratory chain in brain homogenates as well as in single neurons, using laser-capture-microdissection in transgenic mice overexpressing human wildtype α-Syn. Additionally, we used lentivirus-mediated stereotactic delivery of a component of this import machinery into mouse brain as a novel therapeutic strategy. We report here that TOM40 is significantly reduced in the brain of PD patients and in α-Syn transgenic mice. TOM40 deficits were associated with increased mtDNA deletions and oxidative DNA damage, and with decreased energy production and altered levels of complex I proteins in α-Syn transgenic mice. Lentiviral-mediated overexpression of Tom40 in α-Syn-transgenic mice brains ameliorated energy deficits as well as oxidative burden. Our results suggest that alterations in the mitochondrial protein transport machinery might contribute to mitochondrial impairment in α-Synucleinopathies

Synthesis and Growth Mechanism of Ni Nanotubes and Nanowires

Highly ordered Ni nanotube and nanowire arrays were fabricated via electrodeposition. The Ni microstructures and the process of the formation were investigated using conventional and high-resolution transmission electron microscope. Herein, we demonstrated the systematic fabrication of Ni nanotube and nanowire arrays and proposed an original growth mechanism. With the different deposition time, nanotubes or nanowires can be obtained. Tubular nanostructures can be obtained at short time, while nanowires take longer time to form. This formation mechanism is applicable to design and synthesize other metal nanostructures and even compound nanostuctures via template-based electrodeposition