Oxana Klementieva
@lu.se
Lunds universitet
Scopus Publications
Scopus Publications
Ana M. Espinosa‐Oliva, Rocío Ruiz, Manuel Sarmiento Soto, Antonio Boza‐Serrano, Ana I. Rodriguez‐Perez, María A. Roca‐Ceballos, Juan García‐Revilla, Marti Santiago, Sébastien Serres, Vasiliki Economopoulus,et al.
Wiley
AbstractAimsAccording to Braak's hypothesis, it is plausible that Parkinson's disease (PD) originates in the enteric nervous system (ENS) and spreads to the brain through the vagus nerve. In this work, we studied whether inflammatory bowel diseases (IBDs) in humans can progress with the emergence of pathogenic α‐synuclein (α‐syn) in the gastrointestinal tract and midbrain dopaminergic neurons.MethodsWe have analysed the gut and the ventral midbrain from subjects previously diagnosed with IBD and form a DSS‐based rat model of gut inflammation in terms of α‐syn pathology.ResultsOur data support the existence of pathogenic α‐syn in both the gut and the brain, thus reinforcing the potential role of the ENS as a contributing factor in PD aetiology. Additionally, we have analysed the effect of a DSS‐based rat model of gut inflammation to demonstrate (i) the appearance of P‐α‐syn inclusions in both Auerbach's and Meissner's plexuses (gut), (ii) an increase in α‐syn expression in the ventral mesencephalon (brain) and (iii) the degeneration of nigral dopaminergic neurons, which all are considered classical hallmarks in PD.ConclusionThese results strongly support the plausibility of Braak's hypothesis and emphasise the significance of peripheral inflammation and the gut‐brain axis in initiating α‐syn aggregation and transport to the substantia nigra, resulting in neurodegeneration.
Manoj Puthia, Jitka Petrlova, Ganna Petruk, Marta Butrym, Firdaus Samsudin, Madelene Å Andersson, Ann‐Charlotte Strömdahl, Sebastian Wasserstrom, Erik Hartman, Sven Kjellström,et al.
Wiley
AbstractSurgical site infections (SSI) are a clinical and economic burden. Suture‐associated SSI may develop when bacteria colonize the suture surface and form biofilms that are resistant to antibiotics. Thrombin‐derived C‐terminal peptide (TCP)‐25 is a host defense peptide with a unique dual mode of action that can target both bacteria and the excessive inflammation induced by bacterial products. The peptide demonstrates therapeutic potential in preclinical in vivo wound infection models. In this study, the authors set out to explore whether TCP‐25 can provide a new bioactive innate immune feature to hydrophilic polyglactin sutures (Vicryl). Using a combination of biochemical, biophysical, antibacterial, biofilm, and anti‐inflammatory assays in vitro, in silico molecular modeling studies, along with experimental infection and inflammation models in mice, a proof‐of‐concept that TCP‐25 can provide Vicryl sutures with a previously undisclosed host defense capacity, that enables targeting of bacteria, biofilms, and the accompanying inflammatory response, is shown.
Yuriy Pomeshchik, Erika Velasquez, Jeovanis Gil, Oxana Klementieva, Ritha Gidlöf, Marie Sydoff, Silvia Bagnoli, Benedetta Nacmias, Sandro Sorbi, Gunilla Westergren-Thorsson,et al.
Springer Science and Business Media LLC
AbstractThe hippocampus is a primary region affected in Alzheimer’s disease (AD). Because AD postmortem brain tissue is not available prior to symptomatic stage, we lack understanding of early cellular pathogenic mechanisms. To address this issue, we examined the cellular origin and progression of AD pathogenesis by comparing patient-based model systems including iPSC-derived brain cells transplanted into the mouse brain hippocampus. Proteomic analysis of the graft enabled the identification of pathways and network dysfunction in AD patient brain cells, associated with increased levels of Aβ-42 and β-sheet structures. Interestingly, the host cells surrounding the AD graft also presented alterations in cellular biological pathways. Furthermore, proteomic analysis across human iPSC-based models and human post-mortem hippocampal tissue projected coherent longitudinal cellular changes indicative of early to end stage AD cellular pathogenesis. Our data showcase patient-based models to study the cell autonomous origin and progression of AD pathogenesis. Graphical Abstract
M.G. Garcia, A. Paulus, S. Vázquez-Reyes, O. Klementieva, G.K. Gouras, S. Bachiller, and T. Deierborg
Elsevier BV
Sabine C Konings, Emma Nyberg, Isak Martinsson, Laura Torres-Garcia, Oxana Klementieva, Claudia Guimas Almeida, and Gunnar K Gouras
Life Science Alliance, LLC
Apolipoprotein E4 (ApoE4) is the most important genetic risk factor for Alzheimer’s disease (AD). Among the earliest changes in AD is endosomal enlargement in neurons, which was reported as enhanced in ApoE4 carriers. ApoE is thought to be internalized into endosomes of neurons, whereas β-amyloid (Aβ) accumulates within neuronal endosomes early in AD. However, it remains unknown whether ApoE and Aβ intersect intracellularly. We show that internalized astrocytic ApoE localizes mostly to lysosomes in neuroblastoma cells and astrocytes, whereas in neurons, it preferentially localizes to endosomes–autophagosomes of neurites. In AD transgenic neurons, astrocyte-derived ApoE intersects intracellularly with amyloid precursor protein/Aβ. Moreover, ApoE4 increases the levels of endogenous and internalized Aβ42in neurons. Taken together, we demonstrate differential localization of ApoE in neurons, astrocytes, and neuron-like cells, and show that internalized ApoE intersects with amyloid precursor protein/Aβ in neurons, which may be of considerable relevance to AD.
Juan García-Revilla, Antonio Boza-Serrano, Yiyun Jin, Devkee M. Vadukul, Jesús Soldán-Hidalgo, Lluís Camprubí-Ferrer, Marta García-Cruzado, Isak Martinsson, Oxana Klementieva, Rocío Ruiz,et al.
Springer Science and Business Media LLC
AbstractParkinson’s Disease (PD) is a neurodegenerative and progressive disorder characterised by intracytoplasmic inclusions called Lewy bodies (LB) and degeneration of dopaminergic neurons in the substantia nigra (SN). Aggregated α-synuclein (αSYN) is known to be the main component of the LB. It has also been reported to interact with several proteins and organelles. Galectin-3 (GAL3) is known to have a detrimental function in neurodegenerative diseases. It is a galactose-binding protein without known catalytic activity and is expressed mainly by activated microglial cells in the central nervous system (CNS). GAL3 has been previously found in the outer layer of the LB in post-mortem brains. However, the role of GAL3 in PD is yet to be elucidated. In post-mortem samples, we identified an association between GAL3 and LB in all the PD subjects studied. GAL3 was linked to less αSYN in the LB outer layer and other αSYN deposits, including pale bodies. GAL3 was also associated with disrupted lysosomes. In vitro studies demonstrate that exogenous recombinant Gal3 is internalised by neuronal cell lines and primary neurons where it interacts with endogenous αSyn fibrils. In addition, aggregation experiments show that Gal3 affects spatial propagation and the stability of pre-formed αSyn fibrils resulting in short, amorphous toxic strains. To further investigate these observations in vivo, we take advantage of WT and Gal3KO mice subjected to intranigral injection of adenovirus overexpressing human αSyn as a PD model. In line with our in vitro studies, under these conditions, genetic deletion of GAL3 leads to increased intracellular αSyn accumulation within dopaminergic neurons and remarkably preserved dopaminergic integrity and motor function. Overall, our data suggest a prominent role for GAL3 in the aggregation process of αSYN and LB formation, leading to the production of short species to the detriment of larger strains which triggers neuronal degeneration in a mouse model of PD.
Yuriy Pomeshchik, Oxana Klementieva, Jeovanis Gil, Isak Martinsson, Marita Grønning Hansen, Tessa de Vries, Anna Sancho-Balsells, Kaspar Russ, Ekaterina Savchenko, Anna Collin,et al.
Elsevier BV
Craig Prater, Yeran Bai, Sabine C. Konings, Isak Martinsson, Vinay S. Swaminathan, Pontus Nordenfelt, Gunnar Gouras, Ferenc Borondics, and Oxana Klementieva
American Chemical Society (ACS)
Infrared spectroscopic imaging is widely used for the visualization of biomolecule structures, and techniques such as optical photothermal infrared (OPTIR) microspectroscopy can achieve <500 nm spatial resolution. However, these approaches lack specificity for particular cell types and cell components and thus cannot be used as a stand-alone technique to assess their properties. Here, we have developed a novel tool, fluorescently guided optical photothermal infrared microspectroscopy, that simultaneously exploits epifluorescence imaging and OPTIR to perform fluorescently guided IR spectroscopic analysis. This novel approach exceeds the diffraction limit of infrared microscopy and allows structural analysis of specific proteins directly in tissue and single cells. Experiments described herein used epifluorescence to rapidly locate amyloid proteins in tissues or neuronal cultures, thus guiding OPTIR measurements to assess amyloid structures at the subcellular level. We believe that this new approach will be a valuable addition to infrared spectroscopy providing cellular specificity of measurements in complex systems for studies of structurally altered protein aggregates.
Nika Gvazava, Sabine C. Konings, Efrain Cepeda-Prado, Valeriia Skoryk, Chimezie H. Umeano, Jiao Dong, Iran A. N. Silva, Daniella Rylander Ottosson, Nicholas D. Leigh, Darcy Elizabeth Wagner,et al.
American Chemical Society (ACS)
Label-free chemical imaging of living and functioning systems is the holy grail of biochemical research. However, existing techniques often require extensive sample preparation to remove interfering molecules such as water, rendering many molecular imaging techniques unsuitable for in situ structural studies. Here, we examined freshly extracted tissue biopsies and living small vertebrates at submicrometer resolution using optical photothermal infrared (O-PTIR) microspectroscopy and demonstrated the following major advances: (1) O-PTIR can be used for submicrometer structural analysis of unprocessed, fully hydrated tissue biopsies extracted from diverse organs, including living brain and lung tissues. (2) O-PTIR imaging can be performed on living organisms, such as salamander embryos, without compromising their further development. (3) Using O-PTIR, we tracked the structural changes of amyloids in functioning brain tissues over time, observing the appearance of newly formed amyloids for the first time. (4) Amyloid structures appeared altered following standard fixation and dehydration procedures. Thus, we demonstrate that O-PTIR enables time-resolved submicrometer in situ investigation of chemical and structural changes in diverse biomolecules in their native conditions, representing a technological breakthrough for in situ molecular imaging of biological samples.
S. Bachiller, I. Hidalgo, M. G. Garcia, A. Boza-Serrano, A. Paulus, Q. Denis, C. Haikal, O. Manouchehrian, O. Klementieva, J. Y. Li,et al.
Springer Science and Business Media LLC
Abstract Background The risk of developing Alzheimer’s disease (AD) is modulated by genetic and environmental factors. Early-life stress (ELS) exposure during critical periods of brain development can impact later brain function and health, including increasing the risk of developing AD. Microglial dysfunction and neuroinflammation have been implicated as playing a role in AD pathology and may be modulated by ELS. To complicate matters further, sex-specific effects have been noted in response to ELS and in the incidence and progression of AD. Methods Here, we subjected male and female mice with either a wild type or 5xFAD familial AD-model background to maternal separation (MS) from postnatal day 2 to 14 to induce ELS. Results We detected hippocampal neuroinflammatory alterations already at postnatal day 15. By 4 months of age, MS mice presented increased immobility time in the forced swim test and a lower discrimination index in the novel object recognition memory test compared to controls. We found altered Bdnf and Arc expression in the hippocampus and increased microglial activation in the prefrontal cortex due to MS in a sex-dependent manner. In 5xFAD mice specifically, MS exacerbated amyloid-beta deposition, particularly in females. In the periphery, the immune cell population was altered by MS exposure. Conclusion Overall, our results demonstrate that MS has both short- and long-term effects on brain regions related to memory and on the inflammatory system, both in the brain and periphery. These ELS-related effects that are detectable even in adulthood may exacerbate pathology and increase the risk of developing AD via sex-specific mechanisms.
Miriam Solomon, Vito Foderà, Annette Eva Langkilde, Perry Elliott, Fabrizio Tagliavini, Trevor Forsyth, Oxana Klementieva, and Vittorio Bellotti
Springer Science and Business Media LLC
AbstractThis paper is a report of recommendations for addressing translational challenges in amyloid disease research. They were developed during and following an international online workshop organized by the LINXS Institute of Advanced Neutron and X-Ray Science in March 2021. Key suggestions include improving cross-cultural communication between basic science and clinical research, increasing the influence of scientific societies and journals (vis-à-vis funding agencies and pharmaceutical companies), improving the dissemination of negative results, and strengthening the ethos of science.
Agnes Paulus, Sahana Yogarasa, Mustafa Kansiz, Isak Martinsson, Gunnar K. Gouras, Tomas Deierborg, Anders Engdahl, Ferenc Borondics, and Oxana Klementieva
Elsevier BV
Carla Azevedo, Gabriel Teku, Yuriy Pomeshchik, Juan F. Reyes, Margarita Chumarina, Kaspar Russ, Ekaterina Savchenko, Anna Hammarberg, Nuno Jorge Lamas, Anna Collin,et al.
Proceedings of the National Academy of Sciences
Significance Our results demonstrate the existence of early cellular pathways and network alterations in oligodendrocytes in the alpha-synucleinopathies Parkinson’s disease and multiple system atrophy. They further reveal the involvement of an immune component triggered by alpha-synuclein protein, as well as a connection between (epi)genetic changes and immune reactivity in multiple system atrophy. The knowledge generated in this study could be used to devise novel therapeutic approaches to treat synucleinopathies.
Nadja Gustavsson, Ekaterina Savchenko, Oxana Klementieva, and Laurent Roybon
Springer Science and Business Media LLC
AbstractRecent studies suggest that brain cell type specific intracellular environments may play important roles in the generation of structurally different protein aggregates that define neurodegenerative diseases. Using human induced pluripotent stem cells (hiPSC) and biochemical and vibrational spectroscopy techniques, we studied whether Parkinson’s disease (PD) patient genomes could modulate alpha-synuclein (aSYN) protein aggregates formation. We found increased β-sheets and aggregated aSYN in PD patient hiPSC-derived midbrain cells, compared to controls. Importantly, we discovered that aSYN protein aggregation is modulated by patient brain cells’ intracellular milieus at the primary nucleation phase. Additionally, we found changes in the formation of aSYN fibrils when employing cellular extracts from familial PD compared to idiopathic PD, in a Thioflavin T-based fluorescence assay. The data suggest that changes in cellular milieu induced by patient genomes trigger structural changes of aSYN potentially leading to the formation of strains having different structures, properties and seeding propensities.
Nadja Gustavsson, Agnes Paulus, Isak Martinsson, Anders Engdahl, Kadda Medjoubi, Konstantin Klementiev, Andrea Somogyi, Tomas Deierborg, Ferenc Borondics, Gunnar K. Gouras,et al.
Springer Science and Business Media LLC
AbstractAlzheimer’s disease (AD) is the most common cause of dementia, costing about 1% of the global economy. Failures of clinical trials targeting amyloid-β protein (Aβ), a key trigger of AD, have been explained by drug inefficiency regardless of the mechanisms of amyloid neurotoxicity, which are very difficult to address by available technologies. Here, we combine two imaging modalities that stand at opposite ends of the electromagnetic spectrum, and therefore, can be used as complementary tools to assess structural and chemical information directly in a single neuron. Combining label-free super-resolution microspectroscopy for sub-cellular imaging based on novel optical photothermal infrared (O-PTIR) and synchrotron-based X-ray fluorescence (S-XRF) nano-imaging techniques, we capture elemental distribution and fibrillary forms of amyloid-β proteins in the same neurons at an unprecedented resolution. Our results reveal that in primary AD-like neurons, iron clusters co-localize with elevated amyloid β-sheet structures and oxidized lipids. Overall, our O-PTIR/S-XRF results motivate using high-resolution multimodal microspectroscopic approaches to understand the role of molecular structures and trace elements within a single neuronal cell.
Yuriy Pomeshchik, Oxana Klementieva, Jeovanis Gil, Isak Martinsson, Marita Grønning Hansen, Tessa de Vries, Anna Sancho-Balsells, Kaspar Russ, Ekaterina Savchenko, Anna Collin,et al.
Elsevier BV
Raul O. Freitas, Adrian Cernescu, Anders Engdahl, Agnes Paulus, João E. Levandoski, Isak Martinsson, Elke Hebisch, Christophe Sandt, Gunnar Keppler Gouras, Christelle N. Prinz,et al.
MDPI AG
Alzheimer’s disease (AD) accounts for about 70% of neurodegenerative diseases and is a cause of cognitive decline and death for one-third of seniors. AD is currently underdiagnosed, and it cannot be effectively prevented. Aggregation of amyloid-β (Aβ) proteins has been linked to the development of AD, and it has been established that, under pathological conditions, Aβ proteins undergo structural changes to form β-sheet structures that are considered neurotoxic. Numerous intensive in vitro studies have provided detailed information about amyloid polymorphs; however, little is known on how amyloid β-sheet-enriched aggregates can cause neurotoxicity in relevant settings. We used scattering-type scanning near-field optical microscopy (s-SNOM) to study amyloid structures at the nanoscale, in individual neurons. Specifically, we show that in well-validated systems, s-SNOM can detect amyloid β-sheet structures with nanometer spatial resolution in individual neurons. This is a proof-of-concept study to demonstrate that s-SNOM can be used to detect Aβ-sheet structures on cell surfaces at the nanoscale. Furthermore, this study is intended to raise neurobiologists’ awareness of the potential of s-SNOM as a tool for analyzing amyloid β-sheet structures at the nanoscale in neurons without the need for immunolabeling.
Agnes Paulus, Anders Engdahl, Yiyi Yang, Antonio Boza-Serrano, Sara Bachiller, Laura Torres-Garcia, Alexander Svanbergsson, Megg G. Garcia, Gunnar K. Gouras, Jia-Yi Li,et al.
MDPI AG
Alzheimer’s disease affects millions of lives worldwide. This terminal disease is characterized by the formation of amyloid aggregates, so-called amyloid oligomers. These oligomers are composed of β-sheet structures, which are believed to be neurotoxic. However, the actual secondary structure that contributes most to neurotoxicity remains unknown. This lack of knowledge is due to the challenging nature of characterizing the secondary structure of amyloids in cells. To overcome this and investigate the molecular changes in proteins directly in cells, we used synchrotron-based infrared microspectroscopy, a label-free and non-destructive technique available for in situ molecular imaging, to detect structural changes in proteins and lipids. Specifically, we evaluated the formation of β-sheet structures in different monogenic and bigenic cellular models of Alzheimer’s disease that we generated for this study. We report on the possibility to discern different amyloid signatures directly in cells using infrared microspectroscopy and demonstrate that bigenic (amyloid-β, α-synuclein) and (amyloid-β, Tau) neuron-like cells display changes in β-sheet load. Altogether, our findings support the notion that different molecular mechanisms of amyloid aggregation, as opposed to a common mechanism, are triggered by the specific cellular environment and, therefore, that various mechanisms lead to the development of Alzheimer’s disease.
Yuriy Pomeshchik, Oxana Klementieva, Jeovanis Gil, Isak Martinsson, Marita Grønning Hansen, Tessa de Vries, Anna Sancho-Balsells, Kaspar Russ, Ekaterina Savchenko, Anna Collin,et al.
Elsevier BV
Summary The hippocampus is important for memory formation and is severely affected in the brain with Alzheimer disease (AD). Our understanding of early pathogenic processes occurring in hippocampi in AD is limited due to tissue unavailability. Here, we report a chemical approach to rapidly generate free-floating hippocampal spheroids (HSs), from human induced pluripotent stem cells. When used to model AD, both APP and atypical PS1 variant HSs displayed increased Aβ42/Aβ40 peptide ratios and decreased synaptic protein levels, which are common features of AD. However, the two variants differed in tau hyperphosphorylation, protein aggregation, and protein network alterations. NeuroD1-mediated gene therapy in HSs-derived progenitors resulted in modulation of expression of numerous genes, including those involved in synaptic transmission. Thus, HSs can be harnessed to unravel the mechanisms underlying early pathogenic changes in the hippocampi of AD patients, and provide a robust platform for the development of therapeutic strategies targeting early stage AD.
Oxana Klementieva, Christophe Sandt, Isak Martinsson, Mustafa Kansiz, Gunnar K. Gouras, and Ferenc Borondics
Wiley
Abstract Loss of memory during Alzheimer's disease (AD), a fatal neurodegenerative disorder, is associated with neuronal loss and the aggregation of amyloid proteins into neurotoxic β‐sheet enriched structures. However, the mechanism of amyloid protein aggregation is still not well understood due to many challenges when studying the endogenous amyloid structures in neurons or in brain tissue. Available methods either require chemical processing of the sample or may affect the amyloid protein structure itself. Therefore, new approaches, which allow studying molecular structures directly in neurons, are urgently needed. A novel approach is tested, based on label‐free optical photothermal infrared super‐resolution microspectroscopy, to study AD‐related amyloid protein aggregation directly in the neuron at sub‐micrometer resolution. Using this approach, amyloid protein aggregates are detected at the subcellular level, along the neurites and strikingly, in dendritic spines, which has not been possible until now. Here, a polymorphic nature of amyloid structures that exist in AD transgenic neurons is reported. Based on the findings of this work, it is suggested that structural polymorphism of amyloid proteins that occur already in neurons may trigger different mechanisms of AD progression.
Ester Aso, Isak Martinsson, Dietmar Appelhans, Christiane Effenberg, Nuria Benseny-Cases, Josep Cladera, Gunnar Gouras, Isidre Ferrer, and Oxana Klementieva
Elsevier BV
Poly(propylene imine) dendrimers have been shown to be promising 3-dimensional polymers for the use in the pharmaceutical and biomedical applications. Our aims of this study were first, to synthesize a novel type of dendrimer with poly(propylene imine) core and maltose-histidine shell (G4HisMal) assessing if maltose-histidine shell can improve the biocompatibility and the ability to cross the blood-brain barrier, and second, to investigate the potential of G4HisMal to protect Alzheimer disease transgenic mice from memory impairment. Our data demonstrate that G4HisMal has significantly improved biocompatibility and ability to cross the blood-brain barrier in vivo. Therefore, we suggest that a maltose-histidine shell can be used to improve biocompatibility and ability to cross the blood-brain barrier of dendrimers. Moreover, G4HisMal demonstrated properties for synapse and memory protection when administered to Alzheimer disease transgenic mice. Therefore, G4HisMal can be considered as a promising drug candidate to prevent Alzheimer disease via synapse protection.
Nadja Gustavsson, Ana Marote, Yuriy Pomeshchik, Kaspar Russ, Carla Azevedo, Margarita Chumarina, Stefano Goldwurm, Anna Collin, Luisa Pinto, António J. Salgado,et al.
Elsevier BV
Mutations in the glucocerebrosidase (GBA) gene have been associated with the development of Parkinson's disease (PD). An induced pluripotent stem cell (iPSC) line was generated from a 60-year old patient diagnosed with PD and carrying a new mutation variant p.R301C in GBA. Using non-integrating Sendai virus-based technology, we utilized OCT3/4, SOX2, c-MYC and KLF4 transcription factors to reprogram skin fibroblasts into iPSCs. The generated iPSC line retained the mutation, displayed expression of common pluripotency markers, differentiated into the three germ layers, and exhibited normal karyotype. The iPSC line can be further used for studying PD pathogenesis.
Chao Wang, Igor A. Iashchishyn, Jonathan Pansieri, Sofie Nyström, Oxana Klementieva, John Kara, Istvan Horvath, Roman Moskalenko, Reza Rofougaran, Gunnar Gouras,et al.
Springer Science and Business Media LLC
Pro-inflammatory and amyloidogenic S100A9 protein is an important contributor to Alzheimer’s disease (AD) pathology. Traumatic brain injury (TBI) is viewed as a precursor state for AD. Here we have shown that S100A9-driven amyloid-neuroinflammatory cascade was initiated in TBI and may serve as a mechanistic link between TBI and AD. By analyzing the TBI and AD human brain tissues, we demonstrated that in post-TBI tissues S100A9, produced by neurons and microglia, becomes drastically abundant compared to Aβ and contributes to both precursor-plaque formation and intracellular amyloid oligomerization. Conditions implicated in TBI, such as elevated S100A9 concentration, acidification and fever, provide strong positive feedback for S100A9 nucleation-dependent amyloid formation and delay in its proteinase clearance. Consequently, both intracellular and extracellular S100A9 oligomerization correlated with TBI secondary neuronal loss. Common morphology of TBI and AD plaques indicated their similar initiation around multiple aggregation centers. Importantly, in AD and TBI we found S100A9 plaques without Aβ. S100A9 and Aβ plaque pathology was significantly advanced in AD cases with TBI history at earlier age, signifying TBI as a risk factor. These new findings highlight the detrimental consequences of prolonged post-TBI neuroinflammation, which can sustain S100A9-driven amyloid-neurodegenerative cascade as a specific mechanism leading to AD development.
O. Klementieva, J. Mathurin, A. Engdahl, R. Freitas, K. Willen, P. Uvdal, L.M. Miller, and G. Gouras
IEEE
Aβ is a class of aggregation-prone proteins, which may misfold into stable, β-sheet rich fibrils. Aβ is linked to the development of synaptic pathology in Alzheimer's disease (AD). However, a main question in the AD field is how Aβ contributes to AD neuropathology? Up to now there is little evidence for protein structural changes in diseased neuron. Our aim is to study the distribution of β-sheet structures in AD transgenic neurons in order to uncover sub-cellular mechanism(s) by which amyloid β-sheet structures are involved in AD pathology.
Tomas T. Olsson, Oxana Klementieva, and Gunnar K. Gouras
Elsevier BV
Alzheimer's disease (AD) brain tissue can act as a seed to accelerate aggregation of amyloid-β (Aβ) into plaques in AD transgenic mice. Aβ seeds have been hypothesized to accelerate plaque formation in a prion-like manner of templated seeding and intercellular propagation. However, the structure(s) and location(s) of the Aβ seeds remain unknown. Moreover, in contrast to tau and α-synuclein, an in vitro system with prion-like Aβ has not been reported. Here we treat human APP expressing N2a cells with AD transgenic mouse brain extracts to induce inclusions of Aβ in a subset of cells. We isolate cells with induced Aβ inclusions and using immunocytochemistry, western blot and infrared spectroscopy show that these cells produce oligomeric Aβ over multiple replicative generations. Further, we demonstrate that cell lysates of clones with induced oligomeric Aβ can induce aggregation in previously untreated N2a APP cells. These data strengthen the case that Aβ acts as a prion-like protein, demonstrate that Aβ seeds can be intracellular oligomers and for the first time provide a cellular model of nucleated seeding of Aβ.