| 1. |
- Aso, Ester, et al.
(författare)
-
Poly(propylene imine) dendrimers with histidine-maltose shell as novel type of nanoparticles for synapse and memory protection.
- 2019
-
Ingår i: Nanomedicine: Nanotechnology, Biology, and Medicine. - : Elsevier BV. - 1549-9642 .- 1549-9634. ; , s. 198-209
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 2. |
- Augusto Silva, Iran, et al.
(författare)
-
Formalin-free fixation and xylene-free tissue processing preserves cell-hydrogel interactions for histological evaluation of 3D calcium alginate tissue engineered constructs
- 2023
-
Ingår i: Frontiers in Biomaterials Science. - 2813-3749. ; 2-2023:1155919
-
Tidskriftsartikel (refereegranskat)abstract
- Histological evaluation of tissue-engineered products, including hydrogels for cellular encapsulation, is a critical and invaluable tool for assessing the product across multiple stages of its lifecycle from manufacture to implantation. However, many tissue-engineered products are comprised of polymers and hydrogels which are not optimized for use with conventional methods of tissue fixation and histological processing. Routine histology utilizes a combination of chemical fixatives, such as formaldehyde, and solvents such as xylene which have been optimized for use with native biological tissues due to their high protein and lipid content. Previous work has highlighted the challenges associated with processing hydrogels for routine histology due to their high water content and lack of diverse chemical moieties amenable for tissue fixation with traditional fixatives. Thus, hydrogel-based tissue engineering products are prone to histological artifacts during their validation which can lead to challenges in correctly interpreting results. In addition, chemicals used in conventional histological approaches are associated with significant health and environmental concerns due to their toxicity and there is thus an urgent need to identify suitable replacements. Here we use a multifactorial design of experiments approach to identify processing parameters capable of preserving cell-biomaterial interactions in a prototypical hydrogel system: ionically crosslinked calcium alginate. We identify a formalin free fixative which better retains cell-biomaterial interactions and calcium alginate hydrogel integrity as compared to the state-of-the-art formalin-based approaches. In addition, we demonstrate that this approach is compatible with a diversity of manufacturing techniques used to fabricate calcium alginate-based scaffolds for tissue engineering and cell therapy, including histological evaluation of cellular encapsulation in 3D tubes and thin tissue engineering scaffolds (∼50 μm). Furthermore, we show that formalin-free fixation can be used to retain cell-biomaterial interactions and hydrogel architecture in hybrid alginate-gelatin based scaffolds for use with histology and scanning electron microscopy. Taken together, these findings are a significant step forward towards improving histological evaluation of ionically crosslinked calcium alginate hydrogels and help make their validation less toxic, thus more environmentally friendly and sustainable.
|
|
| 3. |
- Azevedo, Carla, et al.
(författare)
-
Parkinsons disease and multiple system atrophy patient iPSC-derived oligodendrocytes exhibit alpha-synuclein-induced changes in maturation and immune reactive properties
- 2022
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:12
-
Tidskriftsartikel (refereegranskat)abstract
- Limited evidence has shed light on how aSYN proteins affect the oligodendrocyte phenotype and pathogenesis in synucleinopathies that include Parkinsons disease (PD) and multiple system atrophy (MSA). Here, we investigated early transcriptomic changes within PD and MSA O4(+) oligodendrocyte lineage cells (OLCs) generated from patient-induced pluripotent stem cells (iPSCs). We found impaired maturation of PD and MSA O4(+) OLCs compared to controls. This phenotype was associated with changes in the human leukocyte antigen (HLA) genes, the immunoproteasome subunit PSMB9, and the complement component C4b for aSYN p.A53T and MSA O4(+) OLCs, but not in SNCA(trip) O4(+) OLCs despite high levels of aSYN assembly formation. Moreover, SNCA overexpression resulted in the development of O4(+) OLCs, whereas exogenous treatment with aSYN species led to significant toxicity. Notably, transcriptome profiling of genes encoding proteins forming Lewy bodies and glial cytoplasmic inclusions revealed clustering of PD aSYN p.A53T O4(+) OLCs with MSA O4(+) OLCs. Our work identifies early phenotypic and pathogenic changes within human PD and MSA O4(+) OLCs.
|
|
| 4. |
- Benseny-Cases, Núria, et al.
(författare)
-
In situ identification and G4-PPI-His-Mal-dendrimer-induced reduction of early-stage amyloid aggregates in Alzheimer’s disease transgenic mice using synchrotron-based infrared imaging
- 2021
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- Amyloid plaques composed of Aβ amyloid peptides and neurofibrillary tangles are a pathological hallmark of Alzheimer Disease. In situ identification of early-stage amyloid aggregates in Alzheimer’s disease is relevant for their importance as potential targets for effective drugs. Synchrotron-based infrared imaging is here used to identify early-stage oligomeric/granular aggregated amyloid species in situ in the brain of APP/PS1 transgenic mice for the first time. Also, APP/PS1 mice show fibrillary aggregates at 6 and 12 months. A significant decreased burden of early-stage aggregates and fibrillary aggregates is obtained following treatment with poly(propylene imine) dendrimers with histidine-maltose shell (a neurodegenerative protector) in 6-month-old APP/PS1 mice, thus demonstrating their putative therapeutic properties of in AD models. Identification, localization, and characterization using infrared imaging of these non-fibrillary species in the cerebral cortex at early stages of AD progression in transgenic mice point to their relevance as putative pharmacological targets. No less important, early detection of these structures may be useful in the search for markers for non-invasive diagnostic techniques.
|
|
| 5. |
- Cárdenes, Rubén, et al.
(författare)
-
3D membrane segmentation and quantification of intact thick cells using cryo soft X-ray transmission microscopy : A pilot study
- 2017
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:4
-
Tidskriftsartikel (refereegranskat)abstract
- Structural analysis of biological membranes is important for understanding cell and subcellular organelle function as well as their interaction with the surrounding environment. Imaging of whole cells in three dimension at high spatial resolution remains a significant challenge, particularly for thick cells. Cryo-transmission soft X-ray microscopy (cryo-TXM) has recently gained popularity to image, in 3D, intact thick cells (∼10μm) with details of subcellular architecture and organization in near-native state. This paper reports a new tool to segment and quantify structural changes of biological membranes in 3D from cryo-TXM images by tracking an initial 2D contour along the third axis of the microscope, through a multi-scale ridge detection followed by an active contours-based model, with a subsequent refinement along the other two axes. A quantitative metric that assesses the grayscale profiles perpendicular to the membrane surfaces is introduced and shown to be linearly related to the membrane thickness. Our methodology has been validated on synthetic phantoms using realistic microscope properties and structure dimensions, as well as on real cryo-TXM data. Results demonstrate the validity of our algorithms for cryo-TXM data analysis.
|
|
| 6. |
- Espinosa-Oliva, Ana M., et al.
(författare)
-
Inflammatory bowel disease induces pathological α-synuclein aggregation in the human gut and brain
- 2024
-
Ingår i: Neuropathology and Applied Neurobiology. - 0305-1846. ; 50:1
-
Tidskriftsartikel (refereegranskat)abstract
- Aims: According 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. Methods: We 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. Results: Our 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. Conclusion: These 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.
|
|
| 7. |
- García-Revilla, Juan, et al.
(författare)
-
Galectin-3 shapes toxic alpha-synuclein strains in Parkinson’s disease
- 2023
-
Ingår i: Acta Neuropathologica. - 0001-6322. ; 146:1, s. 51-75
-
Tidskriftsartikel (refereegranskat)abstract
- Parkinson’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.
|
|
| 8. |
- Gustavsson, Nadja, et al.
(författare)
-
Correlative optical photothermal infrared and X-ray fluorescence for chemical imaging of trace elements and relevant molecular structures directly in neurons
- 2021
-
Ingår i: Light, science & applications. - : Springer Science and Business Media LLC. - 2047-7538. ; 10, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- Alzheimer’s disease (AD) is the most common cause of dementia, costing about 1% of the global economy. Failures ofclinical trials targeting amyloid-βprotein (Aβ), a key trigger of AD, have been explained by drug inefficiency regardlessof the mechanisms of amyloid neurotoxicity, which are very difficult to address by available technologies. Here, wecombine two imaging modalities that stand at opposite ends of the electromagnetic spectrum, and therefore, can beused as complementary tools to assess structural and chemical information directly in a single neuron. Combininglabel-free super-resolution microspectroscopy for sub-cellular imaging based on novel optical photothermal infrared(O-PTIR) and synchrotron-based X-rayfluorescence (S-XRF) nano-imaging techniques, we capture elementaldistribution andfibrillary forms of amyloid-βproteins in the same neurons at an unprecedented resolution. Our resultsreveal that in primary AD-like neurons, iron clusters co-localize with elevated amyloidβ-sheet structures and oxidizedlipids. Overall, our O-PTIR/S-XRF results motivate using high-resolution multimodal microspectroscopic approaches tounderstand the role of molecular structures and trace elements within a single neuronal cell.
|
|
| 9. |
- Gustavsson, Nadja, et al.
(författare)
-
Generation of an induced pluripotent stem cell line (CSC-46) from a patient with Parkinson's disease carrying a novel p.R301C mutation in the GBA gene
- 2019
-
Ingår i: Stem Cell Research. - : Elsevier BV. - 1873-5061. ; 34
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 10. |
- Gustavsson, Nadja, et al.
(författare)
-
The intracellular milieu of Parkinson’s disease patient brain cells modulates alpha-synuclein protein aggregation
- 2021
-
Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- Recent 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.
|
|
| 11. |
- Gvazava, Nika, et al.
(författare)
-
Label-FreeHigh-ResolutionPhotothermalOpticalInfraredSpectroscopyfor Spatiotemporal Chemica lAnalysis in Fresh, Hydrated Living Tissues and Embryos
- 2023
-
Ingår i: Journal of the American Chemical Society. - 1520-5126.
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 12. |
- Kanziz, Mustafa, et al.
(författare)
-
Review of life science applications using submicron O-PTIR and simultaneous Raman microscopy: a new paradigm in vibrational spectroscopy
- 2021
-
Ingår i: Advanced Chemical Microscopy for Life Science and Translational Medicine 2021. - : SPIE. - 2410-9045 .- 1605-7422. - 9781510641471 ; 11656
-
Konferensbidrag (refereegranskat)abstract
- The recent advent of Optical Photothermal IR (O-PTIR), has enabled for the first time, submicron infrared microscopy in far-field reflection mode with the combination of Raman for simultaneous, correlative IR+Raman microscopy. These unique and exciting synergistic capabilities are now spawning interest in life science application. A broad range of life science applications, otherwise impossible with traditional FTIR/QCL microscopy, will be presented, ranging from live cell imaging in water, to ultra-high resolution images of breast tissue calcifications, amyloid aggregates in neurons (neurites and dendritic spines), individual collagen fibrils with polarized IR and individual isotopically labelled bacterial cells and more.
|
|
| 13. |
- Klementieva, Oxana, et al.
(författare)
-
Detection of pre-plaque amyloid aggregation using FTIR
- 2014
-
Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5279 .- 1552-5260. ; 10:4
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Alzheimer's disease (AD) is characterized by misfolding and aggregation of naturally occurring beta-amyloid peptides (Aβ). These aggregates are thought to be pathogenic to neurons, although the conformation of the pathogenic Aβ species remains unclear. Biochemical extraction methods and different microscopy techniques (TEM, confocal) can be used to identify pathogenic Aβ species in the brain, although such methods can alter protein conformation or are n ot designed to determine structural details of protein assemblies.
|
|
| 14. |
- Klementieva, Oxana, et al.
(författare)
-
Glycodendrimers as Potential Multitalented Therapeutics in Alzheimer’s Disease
- 2019
-
Ingår i: Neuroprotection : New Approaches and Prospects - New Approaches and Prospects. - : IntechOpen. - 9781839692611 ; , s. 1-16
-
Bokkapitel (refereegranskat)abstract
- Finding successful therapies for the treatment of Alzheimer’s disease (AD) is one of the most challenging tasks existing for human health. Several drugs have been found and validated in preclinical studies with some success, but not with the desired breakthroughs in the following clinical development phases. AD causes multiple brain dysfunctions that can be described as a brain organ failure, resulting in significant cognitive decline. Aggregation of amyloid proteins and neuronal loss are the hallmarks of AD. Thus, one of the strategies to treat AD is to find a multifunctional drug that may combine both anti-aggregation and neuroprotective properties. Such a candidate could be chemically modified dendrimers. Dendrimers are branched, nonlinear molecules with multiple reactive groups located on their surface. Chemical modification of reactive surface groups defines the property of the dendrimers. In this chapter, I will discuss poly(propylene imine) dendrimers with the surface functionalized with histidine and maltose as an example of a multifunctional therapeutic drug candidate able to protect the memory of AD transgenic model mice.
|
|
| 15. |
- Klementieva, Oxana, et al.
(författare)
-
Super‐Resolution Infrared Imaging of Polymorphic Amyloid Aggregates Directly in Neurons
- 2020
-
Ingår i: Advanced Science. - : Wiley. - 2198-3844.
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 16. |
- Konings, Sabine C, et al.
(författare)
-
Apolipoprotein E intersects with amyloid-β within neurons
- 2023
-
Ingår i: Life Science Alliance. - 2575-1077. ; 6:8
-
Tidskriftsartikel (refereegranskat)abstract
- 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 Aβ 42 in 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.
|
|
| 17. |
- O. Freitas, Raul, et al.
(författare)
-
Nano-Infrared Imaging of Primary Neurons
- 2021
-
Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:10, s. 1-15
-
Tidskriftsartikel (refereegranskat)abstract
- 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
|
|
| 18. |
- Olsson, Tomas T., et al.
(författare)
-
Prion-like seeding and nucleation of intracellular amyloid-β
- 2018
-
Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961. ; 113, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 19. |
- Paulus, Agnes, et al.
(författare)
-
Amyloid Structural Changes Studied by Infrared Microspectroscopy in Bigenic Cellular Models of Alzheimer’s Disease
- 2021
-
Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 22:7
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 20. |
- Paulus, Agnes, et al.
(författare)
-
Correlative imaging to resolve molecular structures in individual cells: Substrate validation study for super-resolution infrared microspectroscopy
- 2022
-
Ingår i: Nanomedicine: Nanotechnology, Biology and Medicine. - : Elsevier BV. - 1549-9642 .- 1549-9634. ; 43, s. 102563-102563
-
Tidskriftsartikel (refereegranskat)abstract
- Light microscopy has been a favorite tool of biological studies for almost a century, recently producing detailed images with exquisite molecular specificity achieving spatial resolution at nanoscale. However, light microscopy is insufficient to provide chemical information as a standalone technique. An increasing amount of evidence demonstrates that optical photothermal infrared microspectroscopy (O-PTIR) is a valuable imaging tool that can extract chemical information to locate molecular structures at submicron resolution. To further investigate the applicability of sub-micron infrared microspectroscopy for biomedical applications, we analyzed the contribution of substrate chemistry to the infrared spectra acquired from individual neurons grown on various imaging substrates. To provide an example of correlative immunofluorescence/O-PTIR imaging, we used immunofluorescence to locate specific organelles for O-PTIR measurement, thus capturing molecular structures at the sub-cellular level directly in cells, which is not possible using traditional infrared microspectroscopy or immunofluorescence microscopy alone.
|
|
| 21. |
|
|
| 22. |
- Pomeshchik, Yuriy, et al.
(författare)
-
Proteomic analysis across patient iPSC-based models and human post-mortem hippocampal tissue reveals early cellular dysfunction and progression of Alzheimer's disease pathogenesis
- 2023
-
Ingår i: Acta Neuropathologica Communications. - 2051-5960. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- The 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.
|
|
| 23. |
- Prater, Craig, et al.
(författare)
-
Fluorescently Guided Optical Photothermal Infrared Microspectroscopy for Protein-Specific Bioimaging at Subcellular Level
- 2023
-
Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 1520-4804 .- 0022-2623. ; 66:4, s. 2542-2549
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 24. |
- Puthia, Manoj, et al.
(författare)
-
Bioactive Suture with Added Innate Defense Functionality for the Reduction of Bacterial Infection and Inflammation
- 2023
-
Ingår i: Advanced healthcare materials. - 2192-2659. ; 12:31
-
Tidskriftsartikel (refereegranskat)abstract
- Surgical 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.
|
|
| 25. |
- Puthia, Manoj, et al.
(författare)
-
Bioactive Suture with Added Innate Defense Functionality for the Reduction of Bacterial Infection and Inflammation
- 2023
-
Ingår i: Advanced Healthcare Materials. - : Wiley. - 2192-2640 .- 2192-2659. ; 12:31, s. 1-20
-
Tidskriftsartikel (refereegranskat)abstract
- Surgical 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.
|
|
