53 research outputs found

    Cervical keratinocytes containing stably replicating extrachromosomal HPV-16 are refractory to transformation by oncogenic H-Ras

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    AbstractRas expression in human epithelial cells with integrated HPV genomes has been shown to cause tumorigenic transformation. The effects of Ras in cells representing early stage HPV-associated disease (i.e., when HPV is extrachromosomal and the oncogenes are under control of native promoters) have not been examined. Here, we used human cervical keratinocyte cell lines containing stably replicating extrachromosomal HPV-16 and present the novel finding that these cells resist transformation by oncogenic H-Ras. Ras expression consistently diminished anchorage-independent growth (AI), reduced E6 and E7 expression, and caused p53 induction in these cells. Conversely, AI was enhanced or maintained in Ras-transduced cervical cells that were immortalized with a 16E6/E7 retrovirus, and minimal effects on E6 and E7 expression were observed. Ras expression with either episomal HPV-16 or LXSN-E6/E7 was insufficient for tumorigenic growth suggesting that other events are needed for tumorigenic transformation. In conclusion, our results indicate that Ras-mediated transformation depends on the context of HPV oncogene expression and that this is an important point to address when developing HPV tumor models

    PDXK mutations cause polyneuropathy responsive to pyridoxal 5'-phosphate supplementation.

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    OBJECTIVE: To identify disease-causing variants in autosomal recessive axonal polyneuropathy with optic atrophy and provide targeted replacement therapy. METHODS: We performed genome-wide sequencing, homozygosity mapping, and segregation analysis for novel disease-causing gene discovery. We used circular dichroism to show secondary structure changes and isothermal titration calorimetry to investigate the impact of variants on adenosine triphosphate (ATP) binding. Pathogenicity was further supported by enzymatic assays and mass spectroscopy on recombinant protein, patient-derived fibroblasts, plasma, and erythrocytes. Response to supplementation was measured with clinical validated rating scales, electrophysiology, and biochemical quantification. RESULTS: We identified biallelic mutations in PDXK in 5 individuals from 2 unrelated families with primary axonal polyneuropathy and optic atrophy. The natural history of this disorder suggests that untreated, affected individuals become wheelchair-bound and blind. We identified conformational rearrangement in the mutant enzyme around the ATP-binding pocket. Low PDXK ATP binding resulted in decreased erythrocyte PDXK activity and low pyridoxal 5'-phosphate (PLP) concentrations. We rescued the clinical and biochemical profile with PLP supplementation in 1 family, improvement in power, pain, and fatigue contributing to patients regaining their ability to walk independently during the first year of PLP normalization. INTERPRETATION: We show that mutations in PDXK cause autosomal recessive axonal peripheral polyneuropathy leading to disease via reduced PDXK enzymatic activity and low PLP. We show that the biochemical profile can be rescued with PLP supplementation associated with clinical improvement. As B6 is a cofactor in diverse essential biological pathways, our findings may have direct implications for neuropathies of unknown etiology characterized by reduced PLP levels. ANN NEUROL 2019;86:225-240

    Inhibition of G-protein signalling in cardiac dysfunction of intellectual developmental disorder with cardiac arrhythmia (IDDCA) syndrome

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    Background: Pathogenic variants of GNB5 encoding the β5 subunit of the guanine nucleotide-binding protein cause IDDCA syndrome, an autosomal recessive neurodevelopmental disorder associated with cognitive disability and cardiac arrhythmia, particularly severe bradycardia. Methods: We used echocardiography and telemetric ECG recordings to investigate consequences of Gnb5 loss in mouse. Results: We delineated a key role of Gnb5 in heart sinus conduction and showed that Gnb5-inhibitory signalling is essential for parasympathetic control of heart rate (HR) and maintenance of the sympathovagal balance. Gnb5-/- mice were smaller and had a smaller heart than Gnb5+/+ and Gnb5+/-, but exhibited better cardiac function. Lower autonomic nervous system modulation through diminished parasympathetic control and greater sympathetic regulation resulted in a higher baseline HR in Gnb5-/- mice. In contrast, Gnb5-/- mice exhibited profound bradycardia on treatment with carbachol, while sympathetic modulation of the cardiac stimulation was not altered. Concordantly, transcriptome study pinpointed altered expression of genes involved in cardiac muscle contractility in atria and ventricles of knocked-out mice. Homozygous Gnb5 loss resulted in significantly higher frequencies of sinus arrhythmias. Moreover, we described 13 affected individuals, increasing the IDDCA cohort to 44 patients. Conclusions: Our data demonstrate that loss of negative regulation of the inhibitory G-protein signalling causes HR perturbations in Gnb5-/- mice, an effect mainly driven by impaired parasympathetic activity. We anticipate that unravelling the mechanism of Gnb5 signalling in the autonomic control of the heart will pave the way for future drug screening

    PDXK mutations cause polyneuropathy responsive to PLP supplementation

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    OBJECTIVE: To identify disease-causing variants in autosomal recessive axonal polyneuropathy with optic atrophy and provide targeted replacement therapy. METHODS: We performed genome-wide sequencing, homozygosity mapping and segregation analysis for novel disease-causing gene discovery. We used circular dichroism to show secondary structure changes and isothermal titration calorimetry to investigate the impact of variants on ATP-binding. Pathogenicity was further supported by enzymatic assays and mass spectroscopy on recombinant protein, patient-derived fibroblasts, plasma and erythrocytes. Response to supplementation was measured with clinical validated rating scales, electrophysiology and biochemical quantification. RESULTS: We identified bi-allelic mutations in PDXK in five individuals from two unrelated families with primary axonal polyneuropathy and optic atrophy. The natural history of this disorder suggests that untreated, affected individuals become wheelchair-bound and blind. We identified conformational rearrangement in the mutant enzyme around the ATP-binding pocket. Low PDXK ATP-binding resulted in decreased erythrocyte PDXK activity and low pyridoxal 5'-phosphate (PLP) concentrations. We rescued the clinical and biochemical profile with PLP supplementation in one family, improvement in power, pain and fatigue contributing to patients regaining their ability to ambulate during the first year of PLP normalization. INTERPRETATION: We show that mutations in PDXK cause autosomal recessive axonal peripheral polyneuropathy leading to disease via reduced PDXK enzymatic activity and low PLP. We show that the biochemical profile can be rescued with PLP supplementation associated with clinical improvement. As B6 is a cofactor in diverse essential biological pathways, our findings may have direct implications for neuropathies of unknown aetiology characterised by reduced PLP levels. This article is protected by copyright. All rights reserved

    Mitochondrial superclusters influence age of onset of Parkinson’s disease in a gender specific manner in the Cypriot population: A case-control study

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    Despite evidence supporting an involvement of mitochondrial dysfunction in the pathogenesis of some neurodegenerative disorders, there are inconsistent findings concerning mitochondrial haplogroups and their association to neurodegenerative disorders, including idiopathic Parkinson's disease (PD).To test this hypothesis for the Greek-Cypriot population, a cohort of 230 PD patients and 457 healthy matched controls were recruited. Mitochondrial haplogroup distributions for cases and controls were determined. Association tests were carried out between mitochondrial haplogroups and PD.Mitochondrial haplogroup U was associated with a reduced PD risk in the Cypriot population. After pooling mitochondrial haplogroups together into haplogroup clusters and superclusters, association tests demonstrated a significantly protective effect of mitochondrial haplogroup cluster N (xR) and supercluster LMN for PD risk only in females. In addition, for female PD cases belonging to UKJT and R (xH, xUKJT) haplogroup, the odds of having a later age of onset of PD were 13 and 15 times respectively higher than the odds for female cases with an H haplogroup.Statistically significant associations regarding PD risk and PD age of onset were mostly detected for females thus suggesting that gender is a risk modifier between mitochondrial haplogroups and PD status / PD age of onset. The biological mechanisms behind this gender specificity remain to be determined

    Sequential detection framework for real-time biosurveillance based on Shiryaev-Roberts procedure with illustrations using COVID-19 incidence data

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    This article develops a detection framework using Bayesian philosophy by adaptation of Shiryaev's and Roberts' methodology. We propose two unifying versions directly applicable in industrial process control and easily extendable to public health infectious disease surveillance via some data detrending and/or demodulation. The root idea uses the sum of likelihood ratios upon which an optimal stopping criterion is based. It sets a prior on the epoch of a change, allows the flexibility to elicit a prior distribution on other process parameters, and attempts to minimize an expected loss function. A sensitivity analysis is conducted for validation and performance assessment and analytical formulas are derived. The methods are successfully applied to the European Union Centre for Disease Control (ECDC) open-source global COVID-19 incidence data. We further lay out scenarios where interest may switch to the detection of separate outbreaks with similar syndromes during an already evolving epidemic. We view our approach as a toolkit with a potential to augment early reports to sentinels in syndromic surveillance and in biosurveillance

    A sequential Bayesian control model for influenza-like illnesses and early detection of intentional outbreaks

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    Data pertaining to influenza and influenza-like illnesses (ILI) are being used in the United States and around the globe to assess evidence of influenza activity, whether it is the natural course of the flu or intentional release of a biological agent with flu-like symptoms. These data, used in surveillance, are unstable, serially correlated, and non-stationary. An important goal is to detect, as soon as possible, either emergence of an epidemic or release of biological agent whose symptoms may be initially classified as ILI. Statistical methodologies for analyzing these data are currently short of being able to capture all their important structural details and are generally deficient. Tools from statistical process control (SPC) are, on the face of it, ideally suited for the task since they address a problem of detecting sudden shift against a background of random variability. However, traditional SPC methods are generally deficient in assuming exact knowledge of the background prevalence and in relying on over simplified models. The objective of this article is to use a Bayesian model to find statistical and data-driven evidence for a surveillance problem based on the U.S. Sentinel ILI data. Bayesian statistical methodologies applied to SPC are very well suited for this setting of partial but imperfect information on the parameters describing these data. This article provides a control algorithm capable to act in detect-to-warn fashion on near-real-time data, to increase the ability to detect unusual surges in the prevalence of ILIs. We defined a model that uses sequential update methods to chart the discrepancy between the observed and predicted incidence of ILI

    Factors affecting the reproductive performance of zebu cattle on the Adamawa Plateau

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    The reproduction of Gudali and Wakwa cattle are investigated. Reproduction data on Gudali and Wakwa cattle on Adamawa Plateau from 1967 to 1988 were analysed. Age at first calving was not affected by breed, year of birth and season of calving (P>.05). Mean calving interval (536.9 ± 17.3 days) was affected
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