The Central Theme of Parkinson’s Disease: α-Synuclein

Parkinson’s disease (PD) is the second most common neurodegenerative disorder, defined by the presence of resting tremor, muscular rigidity, bradykinesia, and postural instability. PD is characterized by the progressive loss of dopaminergic neurons within the substantia nigra pars compacta of the midbrain. The neuropathological hallmark of the disease is the presence of intracytoplasmic inclusions, called Lewy bodies (LBs) and Lewy neurites (LNs), containing α-synuclein, a small protein which is widely expressed in the brain. The α-synuclein gene, SNCA, is located on chromosome 4q22.1; SNCA-linked PD shows an autosomal dominant inheritance pattern with a relatively early onset age, and it usually progresses rapidly. Three missense mutations, A53T, A30P, and E46K, in addition to gene multiplications of the SNCA have been described so far. Although it is clear that LBs and LNs contain mainly the α-synuclein protein, the mechanism(s) which leads α-synuclein to accumulate needs to be elucidated. The primary question in the molecular pathology of PD is how wild-type α-synuclein aggregates in PD, and which interacting partner(s) plays role(s) in the aggregation process. It is known that dopamine synthesis is a stressfull event, and α-synuclein expression somehow affects the dopamine synthesis. The aberrant interactions of α-synuclein with the proteins in the dopamine synthesis pathway may cause disturbances in cellular mechanisms. The normal physiological folding state of α-synuclein is also important for the understanding of pathological aggregates. Recent studies on the α-synuclein protein and genome-wide association studies of the α-synuclein gene show that PD has a strong genetic component, and both familial and idiopathic PD have a common denominator, α-synuclein, at the molecular level. It is clear that the disease process in Parkinson’s disease, as in other neurodegenerative disorders, is very complicated; there can be several different molecular pathways which are responsible for diverse and possibly also unrelated functions inside the neuron, playing roles in PD pathogenesis.     

Statistical shape and appearance models for fast and automated estimation of proximal femur fracture load using 2D finite element models

Estimating the risk of osteoporotic fractures is an important diagnostic step that needs to be taken before medicinal treatment. Densitometry-based criteria are normally used in clinical practice for this purpose. However, densitometry-based techniques could not explain all low-energy fractures. As patient-specific finite element (FE) models allow for consideration of other parameters (e.g. load conditions) that are known to be associated with fracture, they are considered promising candidates for more accurate fracture risk estimation. Nevertheless, they are often time consuming, expensive, and complex to build and may need the type of expertise that is not normally available in clinical settings. In this study, we report the development of an automated platform for estimating proximal femur fracture loads using patient-specific 2D FE models generated using dual-energy x-ray absorptiometry (DXA) scans. First, a statistical shape and appearance model (SSAM) is built using DXA scans of patients screened for osteoporosis following a low energy fracture. SSAM is then used together with Active Appearance Models (AAM) for automated segmentation of the proximal femur from new unseen DXA scans. The mean point-to-curve error of the automated procedure, i.e. 1.2–1.4 mm, is shown to be only slightly larger than the intra-observer variability of manual segmentation, i.e. 1.0 mm. Moreover, the developed platform automatically meshes the segmented shape, assigns density-based mechanical properties, assigns loads and boundary conditions, submits the 2D FE model for solution, and performs post-processing of the 2D FE simulation data to determine fracture loads. The fracture loads predicted using the manually generated and automatically generated 2D FE models are shown to be very close with a mean difference of around 8.8%. Repeated measures ANOVA showed no significant differences between the fracture loads calculated using FE models manually generated by three independent observers and those calculated using the automatically generated FE models (p>0.05).     

The Anti-Inflammatory Activity of Curcumin Protects the Genital Mucosal Epithelial Barrier from Disruption and Blocks Replication of HIV-1 and HSV-2

Inflammation is a known mechanism that facilitates HIV acquisition and the spread of infection. In this study, we evaluated whether curcumin, a potent and safe anti-inflammatory compound, could be used to abrogate inflammatory processes that facilitate HIV-1 acquisition in the female genital tract (FGT) and contribute to HIV amplification. Primary, human genital epithelial cells (GECs) were pretreated with curcumin and exposed to HIV-1 or HIV glycoprotein 120 (gp120), both of which have been shown to disrupt epithelial tight junction proteins, including ZO-1 and occludin. Pre-treatment with curcumin prevented disruption of the mucosal barrier by maintaining ZO-1 and occludin expression and maintained trans-epithelial electric resistance across the genital epithelium. Curcumin pre-treatment also abrogated the gp120-mediated upregulation of the proinflammatory cytokines tumor necrosis factor-α and interleukin (IL)-6, which mediate barrier disruption, as well as the chemokines IL-8, RANTES and interferon gamma-induced protein-10 (IP-10), which are capable of recruiting HIV target cells to the FGT. GECs treated with curcumin and exposed to the sexually transmitted co-infecting microbes HSV-1, HSV-2 and Neisseria gonorrhoeae were unable to elicit innate inflammatory responses that indirectly induced activation of the HIV promoter and curcumin blocked Toll-like receptor (TLR)-mediated induction of HIV replication in chronically infected T-cells. Finally, curcumin treatment resulted in significantly decreased HIV-1 and HSV-2 replication in chronically infected T-cells and primary GECs, respectively. All together, our results suggest that the use of anti-inflammatory compounds such as curcumin may offer a viable alternative for the prevention and/or control of HIV replication in the FGT.     

A new spectrofluorimetric method for the determination of some tetracyclines based on their interfering effect on resonance fluorescence energy transfer

A rapid, simple, inexpensive and highly sensitive spectrofluorimetric method was developed for the determination of trace amounts of some tetracyclines (TCs), namely tetracycline hydrochloride (TCH), oxytetracycline hydrochloride (OTCH) and minocycline hydrochloride (MCH). Binding rhodamine B (RhB) to gold nanoparticles (Au NPs) resulted in quenching of the fluorescence of RhB by a resonance energy transfer (FRET) mechanism, with Au NPs as the energy acceptors. The presence of TCs caused the release of RhB molecules and recovered their fluorescence, and this was used as a basis for the quantitative determination of TCs. The reaction was monitored spectrofluorimetrically by measuring the increase in fluorescence of RhB at 572 nm starting 5 min after mixing the reagents in Tris buffer solution (pH 6.5). The effect of various experimental factors such as buffer type, pH, concentrations of the involved reagents and reaction time were studied to optimize the reaction conditions. Under optimum conditions, the calibration graphs were linear within the ranges 2.08 × 10^?9–1.04 × 10^?6 mol/L, 2.01 × 10^?9–1.00 × 10^?6 mol/L and 2.02 × 10^?9–1.01 × 10^?6 mol/L and detection limits (LODs) of 0.61 × 10^?9, 0.32 × 10^?9 and 0.66 × 10^?9 mol/L were calculated for TCH, OTCH and MCH, respectively, with corresponding percent relative standard deviations (%RSDs) of 1.18, 1.21 and 1.54 (n = 5). The method was successfully applied to the determination of TCs in drinking water, human urine, bovine milk and breast milk samples. Copyright © 2014 John Wiley & Sons, Ltd.     

Mutations in TRIOBP, which encodes a putative cytoskeletal-organizing protein, are associated with nonsyndromic recessive deafness

In seven families, six different mutant alleles of TRIOBP on chromosome 22q13 cosegregate with autosomal recessive nonsyndromic deafness. These alleles include four nonsense (Q297X, R788X, R1068X, and R1117X) and two frameshift (D1069fsX1082 and R1078fsX1083) mutations, all located in exon 6 of TRIOBP. There are several alternative splice isoforms of this gene, the longest of which, TRIOBP-6, comprises 23 exons. The linkage interval for the deafness segregating in these families includes DFNB28. Genetic heterogeneity at this locus is suggested by three additional families that show significant evidence of linkage of deafness to markers on chromosome 22q13 but that apparently have no mutations in the TRIOBP gene.     

Fluorinated Phthalocyanine/Silver Nanoconjugates for Multifunctional Biological Applications

In this study, a new phthalonitrile derivative namely 4-[(2,4-difluorophenyl)ethynyl]phthalonitrile ( 1 ) and its metal phthalocyanines ( 2 and 3 ) were synthesized. The resultant compounds were conjugated to silver nanoparticles and characterized using transmission electron microscopy (TEM) images. The biological properties of compounds ( 1 – 3 ), their nanoconjugates ( 4 – 6 ), and silver nanoparticles ( 7 ) were examined for the first time in this study. The antioxidant activities of biological candidates ( 1 – 7 ) were studied by applying the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The highest antioxidant activity was obtained 97.47 % for 200 mg/L manganese phthalocyanine-silver nanoconjugates ( 6 ). The antimicrobial and antimicrobial photodynamic therapy (APDT) activities of biological candidates ( 1 – 7 ) were examined using a micro-dilution assay. The highest MIC value was obtained 8 mg/L for nanoconjugate 6 against E. hirae. The studied compounds and their silver nanoconjugates exhibited high APDT activities against all the studied microorganisms. The most effective APDT activities were obtained 4 mg/L for nanoconjugates ( 5 and 6 ) against L. pneumophila and E. hirae, respectively. All the studied biological candidates displayed high cell viability inhibition activities against E. coli cell growth. The biofilm inhibition activities of the tested biological candidates were also investigated against S. aureus and P. Aeruginosa. Biological candidates ( 1 – 6 ) can be considered efficient metal nanoparticle-based materials for multi-disciplinary biological applications.     

The Caenorhabditis elegans pumilio homolog, puf-9, is required for the 3'UTR-mediated repression of the let-7 microRNA target gene, hbl-1

The Puf family of RNA-binding proteins directs cell fates by regulating gene expression at the level of translation and RNA stability. Here, we report that the Caenorhabditis elegans pumilio homolog, puf-9, controls the differentiation of epidermal stem cells at the larval-to-adult transition. Genetic analysis reveals that loss-of-function mutations in puf-9 enhance the lethality and heterochronic phenotypes caused by mutations in the let-7 microRNA (miRNA), while suppressing the heterochronic phenotypes of lin-41, a let-7 target and homolog of Drosophila Brat. puf-9 interacts with another known temporal regulator hbl-1, the Caenorhabditis elegans ortholog of hunchback. We present evidence demonstrating that puf-9 is required for the 3'UTR-mediated regulation of hbl-1, in both the hypodermis and the ventral nerve cord. Finally, we show that this regulation is dependent on a region of the hbl-1 3'UTR that contains putative Puf family binding sites as well as binding sites for the let-7 miRNA family, suggesting that puf-9 and let-7 may mediate hypodermal seam cell differentiation by regulating common targets.