16,470 research outputs found

    Roles of the ubiquitin ligase complex CRL5Ozz and its substrate Alix in skeletal muscle

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    Disrupted homeostasis and ciliary defects in VPS13B deficient cells: implications for Cohen syndrome

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    [eng] Cohen syndrome (CS) is an ultra-rare, multi-system, autosomal recessive disorder caused by mutations in the VPS13B gene on chromosome 8q22.2. The most characteristic clinical features of this disorder are microcephaly, intellectual disability, progressive retinal dystrophy, hypotonia, intermittent neutropenia and truncal obesity. Intriguingly, we noticed that CS patients share some clinical features with ciliopathy patients. Ciliopathies are a group of inherited disorders that are caused by defective cilia, small, antenna-like structures on the surface of the vast majority of cells that build tissues and organs in our body. These organelles assemble by an extension of the microtubule structure that constitutes the mother centriole, named axoneme. Since the axoneme protrudes beneath the plasma membrane, the ciliary membrane is formed as an extension of the plasma membrane. Yet, it has a distinct lipid and protein composition that is crucial to its function. Cilia are particularly important for embryo development and for the proper function of various organs. Patients affected by ciliopathies suffer from developmental delay, intellectual disability, obesity, skeletal abnormalities, vision and hearing loss, abnormal organ placement, kidney and liver cysts, and respiratory defects. Despite some overlap of clinical features in CS patients with those of established ciliopathies, VPS13B does not encode a ciliary protein and has not been linked to cilia assembly or function. Instead, VPS13B is associated with the Golgi and was suggested to have a role in maintaining Golgi ribbon structure, but its precise function remains unclear. Additionally, VPS13B belongs to the VPS13 protein family, a group of giant proteins suggested to act as lipid transporters at inter-organelle membrane contact sites, where they bridge membranes and form direct channels for lipid transport. We speculated that VPS13B mutations may indirectly affect cilia by altering the lipid and protein composition of cilia, leading to some of the distinctive phenotypes in CS. To test this, I treated cultured cells with VPS13B siRNAs and analyzed cilia structure and composition. Apart from observing a wide range of cellular defects including mTORC1 downregulation, increased autophagy, G0 arrest and lysosomal structural defects, I also observed a variety of defects at the levels of the primary cilium. These include reduced levels of the lipid PI(4,5)P2 at the ciliary base, longer cilia and inability to activate the Hedgehog signaling pathway. These results suggest that VPS13B indirectly regulates ciliary membrane composition and function. I also analyzed skin fibroblasts from CS patients and compared them with those of healthy controls. Interestingly, despite lacking the full length protein, patients still show a robust signal corresponding to VPS13B at the Golgi complex, suggesting that they might express alternative isoforms that still can localize to this organelle. However, CS cilia were very similar to controls. Curiously, treatment of CS fibroblasts with VPS13B siRNAs gives rise to a plethora of ciliary defects including Hedgehog inactivation. This supports the existence of shorter, at least partially functional VPS13B isoforms in CS patients. To understand if this situation was general or specific to the skin, I decided to investigate disease-relevant tissues. I derived neural rosettes from induced pluripotent stem cells of a healthy control and a CS patient. Interestingly, neural progenitor cells (NPCs) from CS rosettes presented also longer and abnormal cilia compared to control NPCs, suggesting the occurrence of a ciliary impairment in brain-related tissues

    Platelet-activating factor receptor in health and disease.

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    Background Platelet-activating factor receptor (PAFR) expression has been linked to anthropogenic particulate matter (PM). Traffic-related air pollution (TRAP) now accounts for the majority of this PM. PAFR expression has also been linked to an increased risk of infection from Streptococcus pneumoniae (S. pneumoniae). Children with asthma and sickle cell disease (SCD) have a significantly increased risk of morbidity and mortality from invasive pneumococcal disease (IPD). PAFR expression has not yet been investigated in relation to TRAP-generated PM, nor has constitutive expression been investigated in these children at increased risk of IPD. Methods PM10 was collected from roadside traffic using the Cyclone device. A549 cells were exposed to the collected PM10 and flow cytometry was undertaken to measure PAFR expression by median fluorescence intensity (MFI). Exposed A549 cells also underwent assays to determine bacterial adhesion (colony-forming units, CFU) using D39 S. pneumoniae species. In both experiments, Dulbecco’s phosphate buffered saline (DPBS) was used as a control. In a separate study, children aged 1 – 17 years were recruited into 4 groups: 2 disease groups (children with asthma, and those with SCD); and 2 control groups (healthy children, and children with atopy but not asthma). Nasal epithelial cells were collected and PAFR expression (MFI) measured by flow cytometry. 24-hour PM10 pollution (μg/m3) data were also collected for each participant. Results TRAP-related PM caused a significant increase in PAFR expression in A549 cells when exposed to a concentration of 10 ug/ml (p < 0.05). Bacterial adhesion (CFU) was significantly raised in A549 cells exposed to TRAP PM verses the control wells (p < 0.05). In children, PAFR expression in SCD was notably raised when compared to all other groups (p < 0.001). There was no 7 significant difference in the PAFR expression in those with asthma versus the control groups. 24% of the children within the study demonstrated exposure to PM10 levels above the WHO daily safety limit. Conclusion PAFR expression and subsequent bacterial adhesion is increased following exposure to TRAP. PAFR is shown to be constitutively raised in those with SCD and this may explain some of the reported risk from IPD. Air pollution levels in London remain above safe limits despite public health initiatives trying to decrease them

    Fucoidans: exploring its neuroprotective mechanisms and therapeutic applications in brain disorders

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    Background: Marine-derived natural products have been attracting attention from both the food and pharmaceutical sectors due to their promising therapeutic attributes. Algae and their biomolecules are examples of marine-derived products for ongoing research endeavors. Fucoidan, an algae-derived polysaccharide, has emerged as a recent biomolecule related to a diverse array of beneficial properties, with particular emphasis on its neuroprotective activities. Scope and approach: This review intended to understand the neuroprotective properties of Fucoidan and its impact on brain disorders. Fucoidan has risen to prominence as one of the most promising neuroprotective agents obtained from macroalgae, with in vitro and in vivo studies proving its efficiency. Nevertheless, the extant literature underscores the imperative for further clinical trials to substantiate its therapeutic prowess. The neuroprotective effect of fucoidan is related to oxidative stress, mitochondrial function, neuroinflammation, apoptosis, as well as the interaction between gut-brain-microbiota. Key findings and conclusions: Despite having numerous health benefits being approved by regulatory entities, fucoidan products consumption, and use by industry still needs to be explored. Henceforth, there is a need to search for an efficient method for the successful commercialization of fucoidan, focusing on its suitable dosage for pharmaceutical and nutraceutical applications, but it is also necessary to have clinical studies proving its efficacy in brain disorders. Therefore, this biomolecule has the potential to be exploited by researchers, investors and consumers. In this way, fucoidan could contribute to the promotion and improvement of society’s quality of life concerning specific brain pathologies.info:eu-repo/semantics/publishedVersio

    Otitis media: recent advances in otitis media vaccine development and model systems

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    Otitis media is an inflammatory disorder of the middle ear caused by airways-associated bacterial or viral infections. It is one of the most common childhood infections as globally more than 80% of children are diagnosed with acute otitis media by 3 years of age and it is a common reason for doctor’s visits, antibiotics prescriptions, and surgery among children. Otitis media is a multifactorial disease with various genetic, immunologic, infectious, and environmental factors predisposing children to develop ear infections. Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis are the most common culprits responsible for acute otitis media. Despite the massive global disease burden, the pathogenesis of otitis media is still unclear and requires extensive future research. Antibiotics are the preferred treatment to cure middle ear infections, however, the antimicrobial resistance rate of common middle ear pathogens has increased considerably over the years. At present, pneumococcal and influenza vaccines are administered as a preventive measure against otitis media, nevertheless, these vaccines are only beneficial in preventing carriage and/or disease caused by vaccine serotypes. Otitis media caused by non-vaccine serotype pneumococci, non-typeable H. influenza, and M. catarrhalis remain an important healthcare burden. The development of multi-species vaccines is an arduous process but is required to reduce the global burden of this disease. Many novel vaccines against S. pneumoniae, non-typeable H. influenza, and M. catarrhalis are in preclinical trials. It is anticipated that these vaccines will lower the disease burden and provide better protection against otitis media. To study disease pathology the rat, mouse, and chinchilla are commonly used to induce experimental acute otitis media to test new therapeutics, including antibiotics and vaccines. Each of these models has its advantages and disadvantages, yet there is still a need to develop an improved animal model providing a better correlated mechanistic understanding of human middle ear infections, thereby underpinning the development of more effective otitis media therapeutics. This review provides an updated summary of current vaccines against otitis media, various animal models of otitis media, their limitations, and some future insights in this field providing a springboard in the development of new animal models and novel vaccines for otitis media

    The Structure and Function of the Retina in Multiple Sclerosis

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    Background: Multiple sclerosis (MS) is a complex heterogenous autoimmune inflammatory disease with a prolonged and variable time course. The visual system is frequently implicated, either as the presenting symptom, or, with advancement of the disease. This has been documented in the literature with changes in visual acuity (VA) that are accompanied by functional changes in the optic nerve, measured with the visual evoked potential (VEP) and possible retrograde degeneration involving the retinal ganglion cells in the retina, measured with the pattern reversal electroretinogram (PERG). However, inflammatory episodes may be clinical or subclinical in nature and may go unrecognised. Originating from the same embryological origins, the effect of inflammation in MS on the on the retina is less well known. The research hypothesis was that there is a measurable difference in the function of retinal cells in patients with newly diagnosed multiple sclerosis, suggestive of inflammatory retinopathy compared to healthy controls. The overall aim was to investigate any differences in the electrophysiological function of the visual pathway of patients newly diagnosed with MS compared to healthy controls. Methods: The visual system is explored with clinical (VA), electrophysiology (VEP and electroretinography (ERG – pattern and flash) and structural (OCT) measures, in patients presenting with symptoms suggestive of MS to a specialist service. This prospective case control study investigates the visual pathway at the earliest stage of the disease to look for differences in structure and function between patients and healthy volunteers that might serve as a biomarker in the future. Results: There were a number of variables that were significantly different between the two groups, logistic regression analysis found that VA (p 0.038) and VEP P100 peak-time (p 0.014) from the right eye as significant. Dividing the participants by prolongation of the VEP P100 peak-time as defined in clinical practice, found a number of ERG amplitude variables as well as VA that were consistently different between the groups regardless of symptoms. Conclusion: The study confirms optic nerve involvement in MS with VEP and VA abnormalities consistent with the literature in this cohort. Additionally, VA and some ERG amplitude variables were significantly reduced in participants with MS, when grouped according to VEP P100 peak-time, suggesting inner and outer retinal changes. Further work would be required to confirm these findings. No OCT structural changes were found in any of the analysis that included the macula thickness, ganglion cell layer or retinal nerve fibre layer. Keywords: multiple sclerosis (MS), visual evoked potential (VEP), pattern electroretinogram (PERG), electroretinogram (ERG), optical coherence tomography (OCT

    Increasing Sustainable Bivalve Aquaculture Productivity Using Remote Non-Invasive Sensing and Upweller Technologies

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    The work and findings described by this thesis aim to develop technologies and approaches relevant to bivalve aquaculture, focusing on non invasive sensing to monitor bivalve shellfish, primarily the Pacific oyster (Magallana gigas). Following the introduction, Chapter 2 presents an overview of the Non Invasive Oyster Sensor (NOSy), a sensor developed at the University of Essex that records bivalve openness (gape). NOSy was conceived to automatically detect spawning as an aid to oyster growers and has proved useful in field and laboratory, work which underpins three chapters in this thesis. NOSy remains under development, and has potential for use in aquaculture, monitoring and research. Chapter 3 assesses the role of salinity in driving estuarine oyster behaviour. We replicated an estuarine tidal salinity cycle and recorded the gape of oysters exposed to it. Behaviours during the experiment did not resemble those in the estuary, suggesting that salinity alone does not drive estuarine oyster behaviour. We also discuss the challenges of controlling salinity in a laboratory, and suggest it is an under-studied area. Chapter 4 discusses land based systems for young oyster growing. Land-based systems have the potential to improve growth, condition and survival while reducing labour and maintenance costs. We trialled a system over three summers, with promising results. Reduction of localised densities improved growth rate and uniformity. Cost forecasts suggest that adoption of land based growing systems could result in substantial savings. Chapter 5 presents gaping records from an area where Blue mussels (Mytilus edulis) have become non harvestable in recent years due to contamination. We used NOSy to assess gaping patterns of the mussel population to evaluate how their behaviours affect their vulnerability to contamination. Mussels in the bay closed over low tide as a response to extremely low salinity, inferring protection from contamination by limiting the mussel’s exposure

    Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

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    Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

    Toxicological effects of cadmium on deep-sea mussel Gigantidas platifrons revealed by a combined proteomic and metabolomic approach

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    IntroductionMarine metal contamination caused by deep-sea mining activities has elicited great concern from both social and scientific communities. Among the various metals deep-sea organisms might encounter, cadmium (Cd) is a widely detected metal that in very small amounts is nonetheless capable of severe toxicity. Yet due to both remoteness and technical challenges, insights into the effects of metal exposure resulting from mining activities upon deep-sea organisms are limited.MethodsHere, we investigated Cd’s toxicological effects on deep-sea mussels of Gigantidas platifrons exposed to 100 or 1000 g/L of Cd for 7 days; an integrated approach was used that incorporated proteomics and metabolomics along with traditional approaches (metal concentrations, metal subcellular distribution, and anti-oxidative and immune-related biochemical indexes).Results and DiscussionResults showed that Cd exposure caused significant Cd’s accumulation in mussel gills and redistribution of Cd among subcellular compartments, with cellular debris being the primary binding site. Although anti-oxidative enzymes activities (superoxide dismutase and catalase) were not significantly altered in mussel gills of both exposed groups, the markedly increased level of glutathione S-transferase detected via proteomic technique clearly evinced that deep-sea mussels suffered from oxidative stress under Cd exposure. Besides, altered activities of acid phosphatase and alkaline phosphatase assayed by traditional methods along with the predominant presence of largely altered immune-related proteins detected by proteomic data strongly revealed an immune response of deep-sea mussels elicited by Cd. In addition, results of proteomics combined with those of non-targeted metabolomics demonstrated that Cd could exert toxicity by disrupting cytoskeleton structure, ion homeostasis, and primary metabolisms of energy, lipid, and nucleotide in deep-sea mussels. As demonstrated in this study, proteomics and metabolomics can be used in tandem to provide valuable insights into the molecular mechanisms of deep-sea organisms’ response to Cd exposure and for helping to discover potential biomarkers for application during deep-sea mining assessments

    Current Challenges and Advances in Cataract Surgery

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    This reprint focuses on new trials related to cataract surgery, intraocular lens power calculations for cataracts after refractive surgery, problems related to high myopia, toric IOL power calculations, etc. Intraoperative use of the 3D Viewing System and OCT, studies on the spectacle dependence of EDOF, IOL fixation status and visual function, and dry eye after FLAC are also discussed. Proteomic analysis of aqueous humor proteins is also discussed
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