25 research outputs found

    Polymerogenic neuroserpin causes mitochondrial alterations and activates NFÎşB but not the UPR in a neuronal model of neurodegeneration FENIB

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    The neurodegenerative condition FENIB (familiar encephalopathy with neuroserpin inclusion bodies) is caused by heterozygous expression of polymerogenic mutant neuroserpin (NS), with polymer deposition within the endoplasmic reticulum (ER) of neurons. We generated transgenic neural progenitor cells (NPCs) from mouse fetal cerebral cortex stably expressing either the control protein GFP or human wild type, polymerogenic G392E or truncated (delta) NS. This cellular model makes it possible to study the toxicity of polymerogenic NS in the appropriated cell type by in vitro differentiation to neurons. Our previous work showed that expression of G392E NS in differentiated NPCs induced an adaptive response through the upregulation of several genes involved in the defence against oxidative stress, and that pharmacological reduction of the antioxidant defences by drug treatments rendered G392E NS neurons more susceptible to apoptosis than control neurons. In this study, we assessed mitochondrial distribution and found a higher percentage of perinuclear localisation in G392E NS neurons, particularly in those containing polymers, a phenotype that was enhanced by glutathione chelation and rescued by antioxidant molecules. Mitochondrial membrane potential and contact sites between mitochondria and the ER were reduced in neurons expressing the G392E mutation. These alterations were associated with a pattern of ER stress that involved the ER overload response but not the unfolded protein response. Our results suggest that intracellular accumulation of NS polymers affects the interaction between the ER and mitochondria, causing mitochondrial alterations that contribute to the neuronal degeneration seen in FENIB patients

    Characterizing wing tears in common pipistrelles (Pipistrellus pipistrellus): investigating tear distribution, wing strength, and possible causes

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    Bats have large, thin wings that are particularly susceptible to tearing. Anatomical specializations, such as fiber reinforcement, strengthen the wing and increase its resistance to puncture, and an extensive vasculature system across the wing also promotes healing. We investigated whether tear positioning is associated with anatomy in common pipistrelles (Pipistrellus pipistrellus). Wing anatomy was described using histological techniques, imaging, and material testing. Tear information, including type, position, time in rehabilitation, and possible causes, was collected from rehabilitators of injured bats across the United Kingdom. Results suggest that the position of the plagiopatagium (the most proximal wing section to the body), rather than its anatomy, influenced the number, location, and orientation of wing tears. While material testing did not identify the plagiopatagium as being significantly weaker than the chiropatagium (the more distal sections of the wing), the plagiopatagium tended to have the most tears. The position of the tears, close to the body and toward the trailing edge, suggests that they are caused by predator attacks, such as from a cat (Felis catus), rather than collisions. Consistent with this, 38% of P. pipistrellus individuals had confirmed wing tears caused by cats, with an additional 38% identified by rehabilitators as due to suspected cat attacks. The plagiopatagium had the lowest number of blood vessels and highest amounts of elastin fibers, suggesting that healing may take longer in this section. Further investigations into the causes of tears, and their effect on flight capabilities, will help to improve bat rehabilitation

    Early evidence for bear exploitation during MIS 9 from the site of Schöningen 12 (Germany)

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    A cutmarked bear metatarsal and phalanx from the German open-air sites of Schoningen 12 II-1 and 12 B, respectively, correlated with the interglacial optimum of MIS 9 (ca. 320 ka), provide early evidence for the exploitation of bear skins. Archaeological sites with evidence of bear exploitation from the Lower Paleolithic are rare, with only Boxgrove (United Kingdom) and Bilzingsleben (Germany) yielding cutmarked bear bones indicating skinning. We interpret these finds as evidence for bear hunting and primary access since bear skins are best extracted shortly after the animal's death. The very thin cutmarks found on the Schoningen specimens indicate delicate butchering and show similarities in butchery € patterns to bears from other Paleolithic sites. The Eurasian Lower Paleolithic record does not show any evidence for the exploitation of bear meat; only Middle Paleolithic sites, such as Biache-Saint-Vaast (France; ca. 175 ka) and Taubach (Germany; ca. 120 ka), yield evidence for the exploitation of both skin and meat from bear carcasses. Bear skins have high insulating properties and might have played a role in the adaptations of Middle Pleistocene hominins to the cold and harsh winter conditions of Northwestern Europe.Bioarchaeolog

    Characterizing the Lower Paleolithic bone industry from Schöningen 12 II: A multi-proxy study

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    Although preservation of Paleolithic faunal assemblages from open-air settings is often poor, the Lower Paleolithic sites of Schöningen provide exceptionally well-preserved mammalian faunal material for investigating hominin/animal relationships. Pleistocene fossil assemblages, however, usually reflect a complex taphonomic history in which natural and anthropogenic processes are often superimposed. A number of examples of osseous finds that resemble tools were recently discovered in the MIS 9 deposits of Schöningen 12 II. Non-anthropogenic agents are known to produce surface modifications mimicking human artifacts and the identification of osseous remains used and/or deliberately modified by ancient hominins is often controversial in such old contexts. Multiple lines of evidence are thus useful for distinguishing between osseous artifacts and “eco-facts”. In this paper, the recognition of the use of bone for different technological purposes by late Middle Pleistocene hominins is addressed through a multi-proxy study combining geoarcheology, bone taphonomy, zooarcheology, and use-wear analysis. This allowed the identification of the processes and agents responsible for the formation and modification of the different bone assemblages of Schöningen 12 II. Our analysis points to different types of bones having been likely used as tools. These results expand the diversity of the organic technological repertoire of the Middle Pleistocene hominins, making Schöningen 12 II a remarkable new source of information on osseous technology long before the Upper Paleolithic, the period traditionally viewed as the start of the systematic use of bone tools. Together with other observations of bone tools documented during the Lower and Middle Paleolithic, the results from Schöningen show that archeologists may have underestimated the diversity and importance of osseous technology among archaic hominins
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