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Mono- and polyunsaturated fatty acids (FAs) are broadly used as food supplements. However, their effect on the aggregation of amyloidogenic proteins remains unclear. In this study, we investigated the effect of a large number of mono- and polyunsaturated, as well as fully saturated FAs on the aggregation of amyloid ß1-42 (Aß1-42) peptide. A progressive aggregation of this peptide is the expected molecular cause of Alzheimer's disease (AD), one of the most common neurodegenerative pathologies in the world. We found that arachidonic and stearic acids delayed the aggregation of Aß1-42. Using Nano-Infrared spectroscopy, we found that FAs caused very little if any changes in the secondary structure of Aß1-42 oligomers and fibrils formed at different stages of protein aggregation. However, the analyzed mono- and polyunsaturated, as well as fully saturated FAs uniquely altered the toxicity of Aß1-42 fibrils. We found a direct relationship between the degree of FAs unsaturation and toxicity of Aß1-42 fibrils formed in their presence. Specifically, with an increase in the degree of unsaturation, the toxicity Aß1-42/FA fibrils increased. These results indicate that fully saturated or monounsaturated FAs could be used to decrease the toxicity of amyloid aggregates and, consequently, decelerate the development of AD.
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Forensic entomology plays an important role in medicolegal investigations by using insects, primarily flies, to estimate the time of colonization. This estimation relies on the development of the flies found at the (death) scene and can be affected (and sometimes corrected) by external factors, such as temperature and humidity, and internal factors, such as species and sex. This study leverages infrared (IR) spectroscopy combined with machine learning models-Partial Least Squares Discriminant Analysis (PLS-DA) and eXtreme Gradient Boosting trees Discriminant Analysis (XGBDA)-to differentiate between male and female Cochliomyia macellaria larvae, commonly found on human remains. Significant vibrational differences were detected in the infrared spectra of third instar C. macellaria larvae, with distinct peaks showing variations in relative absorbance between sexes, suggesting differences in biochemical compositions such as cuticular proteins and lipids. The application of PLS-DA and XGBDA yielded high classification accuracies of about 94% and 96%, respectively, with female spectra consistently having higher sensitivity than males. This non-destructive approach offers the potential to refine supplemental post-mortem interval estimations significantly, enhancing the accuracy of forensic analyses.
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A progressive aggregation of Tau proteins in the brain is linked to both Alzheimer's disease (AD) and various Tauopathies. This pathological process can be enhanced by several substances, including heparin. However, very little if anything is known about molecules that can inhibit the aggregation of Tau isoforms. In this study, we examined the effect of phosphatidylserines (PSs) with various lengths and saturations of fatty acids (FAs) on the aggregation properties of Tau isoforms with one (1N4R) and two (2N4R) N-terminal inserts that enhance binding of Tau to tubulin. We found that PS with unsaturated and short-length FAs inhibited Tau aggregation and drastically lowered the toxicity of Tau oligomers that were formed in the presence of such phospholipids. Such an effect was not observed for PS with fully saturated long-chain FAs. These results suggest that a short-chain irreversible disbalance between saturated and unsaturated lipids in the brain could be the trigger of Tau aggregation.
Assuntos
Fosfolipídeos , Proteínas tau , Proteínas tau/metabolismo , Proteínas tau/química , Humanos , Fosfolipídeos/química , Fosfolipídeos/metabolismo , Agregados Proteicos/efeitos dos fármacos , Heparina/química , Heparina/farmacologia , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Fosfatidilserinas/química , Fosfatidilserinas/metabolismo , Tubulina (Proteína)/metabolismo , Tubulina (Proteína)/químicaRESUMO
An unprecedented extension of life expectancy observed during the past century drastically increased the number of patients diagnosed with Parkinson's diseases (PD) worldwide. Estimated costs of PD alone reached $52 billion per year, making effective neuroprotective treatments an urgent and unmet need. Current treatments of both AD and PD focus on mitigating the symptoms associated with these pathologies and are not neuroprotective. In this review, we discuss the most advanced therapeutic strategies that can be used to treat PD. We also critically review the shift of the therapeutic paradigm from a small molecule-based inhibition of protein aggregation to the utilization of natural degradation pathways and immune cells that are capable of degrading toxic amyloid deposits in the brain of PD patients.
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Confirmatory identification of dyes in the physical pieces of evidence, such as hair and fabric, is critically important in forensics. This information can be used to demonstrate the link between a person of interest and a crime scene. High performance liquid chromatography is broadly used for dye analysis. However, this technique is destructive and laborious. This problem can be overcome by near-Infrared excitation Raman spectroscopy (NIeRS), non-invasive and non-destructive technique that can be used to determine chemical structure of highly fluorescent dyes. Analyzed fabric materials often possess body fluid stains, which may obscure the accuracy of NIeRS-based identification of dyes. In this study, we investigate the extent to which fabric contamination with body fluids can alter the accuracy of NIeRS. Our results showed that NIeRS coupled with partial-least squared discriminant analysis (PLS-DA) enabled on average 97.6% accurate identification of dyes on fabric contaminated with dry blood, urine and semen. We also found that NIeRS could be used to identify blood, urine and semen on such fabric with 99.4% accuracy. Furthermore, NIeRS could be used to differentiate between wet and dry blood, as well as reveal the presence of blood on washed fabric. These results indicate that NIeRS coupled with PLS-DA could be used as a robust and reliable analytical approach in forensic analysis of fabric.
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Análise Espectral Raman , Têxteis , Análise Espectral Raman/métodos , Têxteis/análise , Humanos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Líquidos Corporais/química , Sêmen/química , Corantes/química , Corantes/análise , Ciências Forenses/métodosRESUMO
α-Synuclein (α-syn) is a small protein that is involved in cell vesicle trafficking in neuronal synapses. A progressive aggregation of this protein is the expected molecular cause of Parkinson's disease, a disease that affects millions of people around the world. A growing body of evidence indicates that phospholipids can strongly accelerate α-syn aggregation and alter the toxicity of α-syn oligomers and fibrils formed in the presence of lipid vesicles. This effect is attributed to the presence of high copies of lysines in the N-terminus of the protein. In this study, we performed site-directed mutagenesis and replaced one out of two lysines at each of the five sites located in the α-syn N-terminus. Using several biophysical and cellular approaches, we investigated the extent to which six negatively charged fatty acids (FAs) could alter the aggregation properties of K10A, K23A, K32A, K43A, and K58A α-syn. We found that FAs uniquely modified the aggregation properties of K43A, K58A, and WT α-syn, as well as changed morphology of amyloid fibrils formed by these mutants. At the same time, FAs failed to cause substantial changes in the aggregation rates of K10A, K23A, and K32A α-syn, as well as alter the morphology and toxicity of the corresponding amyloid fibrils. Based on these results, we can conclude that K10, K23, and K32 amino acid residues play a critical role in protein-lipid interactions since their replacement on non-polar alanines strongly suppressed α-syn-lipid interactions.
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Mutagênese Sítio-Dirigida , alfa-Sinucleína , alfa-Sinucleína/metabolismo , alfa-Sinucleína/genética , Humanos , Amiloide/metabolismo , Amiloide/genética , Ácidos Graxos/metabolismoRESUMO
Alzheimer's disease is the fastest-growing neurodegenerative disease that affects over six million Americans. The abnormal aggregation of amyloid ß peptide and Tau protein is the expected molecular cause of the loss of neurons in brains of AD patients. A growing body of evidence indicates that lipids can alter the aggregation rate of amyloid ß peptide and modify the toxicity of amyloid ß aggregates. However, the role of lipids in Tau aggregation remains unclear. In this study, we utilized a set of biophysical methods to determine the extent to which phospatidylserine (PS) altered the aggregation properties of Tau isoforms with one (1N4R) and two (2N4R) N terminal inserts that enhance the binding of Tau to tubulin. We found that the length and saturation of fatty acids (FAs) in PS altered the aggregation rate of 2N4R isoform, while no changes in the aggregation rate of 1N4R were observed. These results indicate that N terminal inserts play an important role in protein-lipid interactions. We also found that PS could change the toxicity of 1N4R and 2N4R Tau fibrils, as well as alter molecular mechanisms by which these aggregates exert cytotoxicity to neurons. Finally, we found that although Tau fibrils formed in the presence and absence of PS endocytosed by cells, only fibril species that were formed in the presence of PS exert strong impairment of the cell mitochondria.
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Fosfatidilserinas , Tubulina (Proteína) , Proteínas tau , Proteínas tau/metabolismo , Proteínas tau/química , Proteínas tau/toxicidade , Humanos , Fosfatidilserinas/metabolismo , Fosfatidilserinas/química , Tubulina (Proteína)/metabolismo , Tubulina (Proteína)/química , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Ligação Proteica , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Agregados Proteicos , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/químicaRESUMO
Abrupt aggregation of amyloid ß1-42 (Aß1-42) peptide in the frontal lobe is the expected underlying cause of Alzheimer's disease (AD). ß-Sheet-rich oligomers and fibrils formed by Aß1-42 exert high cell toxicity. A growing body of evidence indicates that lipids can uniquely alter the secondary structure and toxicity of Aß1-42 aggregates. At the same time, underlying molecular mechanisms that determine this difference in toxicity of amyloid aggregates remain unclear. Using a set of molecular and biophysical assays to determine the molecular mechanism by which Aß1-42 aggregates formed in the presence of cholesterol, cardiolipin, and phosphatidylcholine exert cell toxicity. Our findings demonstrate that rat neuronal cells exposed to Aß1-42 fibrils formed in the presence of lipids with different chemical structure exert drastically different magnitude and dynamic of unfolded protein response (UPR) in the endoplasmic reticulum (ER) and mitochondria (MT). We found that the opposite dynamics of UPR in MT and ER in the cells exposed to Aß1-42: cardiolipin fibrils and Aß1-42 aggregates formed in a lipid-free environment. We also found that Aß1-42: phosphatidylcholine fibrils upregulated ER UPR simultaneously downregulating the UPR response of MT, whereas Aß1-42: cholesterol fibrils suppressed the UPR response of ER and upregulated UPR response of MT. We also observed progressively increasing ROS production that damages mitochondrial membranes and other cell organelles, ultimately leading to cell death.
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Peptídeos beta-Amiloides , Mitocôndrias , Fragmentos de Peptídeos , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/toxicidade , Animais , Ratos , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/toxicidade , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Cardiolipinas/metabolismo , Colesterol/metabolismo , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/patologia , Amiloide/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Fosfatidilcolinas/metabolismo , Fosfatidilcolinas/química , Humanos , Espécies Reativas de Oxigênio/metabolismoRESUMO
Rice (Oryza sativa) is the primary crop for nearly half of the world's population. Groundwater in many rice-growing parts of the world often has elevated levels of arsenite and arsenate. At the same time, rice can accumulate up to 20 times more arsenic compared to other staple crops. This places an enormous amount of people at risk of chronic arsenic poisoning. In this study, we investigated whether Raman spectroscopy (RS) could be used to diagnose arsenic toxicity in rice based on biochemical changes that were induced by arsenic accumulation. We modeled arsenite and arsenate stresses in four different rice cultivars grown in hydroponics over a nine-day window. Our results demonstrate that Raman spectra acquired from rice leaves, coupled with partial least squares-discriminant analysis, enabled accurate detection and identification of arsenic stress with approximately 89% accuracy. We also performed high-performance liquid chromatography (HPLC)-analysis of rice leaves to identify the key molecular analytes sensed by RS in confirming arsenic poisoning. We found that RS primarily detected a decrease in the concentration of lutein and an increase in the concentration of vanillic and ferulic acids due to the accumulation of arsenite and arsenate in rice. This showed that these molecules are detectable indicators of biochemical response to arsenic accumulation. Finally, a cross-correlation of RS with HPLC and ICP-MS demonstrated RS's potential for a label-free, non-invasive, and non-destructive quantification of arsenic accumulation in rice.
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Heart tissue can experience a progressive accumulation of transthyretin (TTR), a small four subunit protein that transports holoretinol binding protein and thyroxine. This severe pathology is known as transthyretin amyloid cardiomyopathy. Numerous experimental studies indicated that the aggregation rate and toxicity of TTR fibrils could be altered by the presence of lipids; however, the role of plasmalogens in this process remains unknown. In this study, we investigate the effect of choline plasmalogens (CPs) with different lengths and saturations of fatty acids (FAs) on TTR aggregation. We found that CPs with saturated and unsaturated FAs strongly suppressed TTR aggregation. We also found that CPs with saturated FAs did not change the morphology of TTR fibrils; however, much thicker fibrillar species were formed in the presence of CPs with unsaturated FAs. Finally, we found that CPs with C16:0, C18:0, and C18:1 FAs substantially lowered the cytotoxicity of TTR fibrils that were formed in their presence.
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Plasmalogênios , Pré-Albumina , Pré-Albumina/química , Pré-Albumina/metabolismo , Plasmalogênios/metabolismo , Plasmalogênios/química , Humanos , Amiloide/química , Amiloide/metabolismo , Agregados Proteicos/efeitos dos fármacos , Ácidos Graxos/química , Ácidos Graxos/metabolismoRESUMO
Amyloid oligomers and fibrils are protein aggregates that exert a high cell toxicity. Efficient degradation of these protein aggregates can minimize the spread and progression of neurodegeneration. In this study, we investigate the properties of natural killer (NK) cells and macrophages in the degradation of α-synuclein (α-Syn) aggregates grown in a lipid-free environment and in the presence of phosphatidylserine and cholesterol (PS/Cho), which are lipids that are directly associated with the onset and progression of Parkinson's disease. We found that both types of α-Syn aggregates were endocytosed by neurons, which caused strong damage to cell endosomes. Our results also indicated that PS/Cho vesicles drastically increased the toxicity of α-Syn fibrils formed in their presence compared to the toxicity of α-Syn aggregates grown in a lipid-free environment. Both NK cells and macrophages were able to degrade α-Syn and α-Syn/Cho monomers, oligomers, and fibrils. Quantitative analysis of protein degradation showed that macrophages demonstrated substantially more efficient internalization and degradation of amyloid aggregates in comparison to NK cells. We also found that amyloid aggregates induced the proliferation of macrophages and NK cells and significantly changed the expression of their cytokines and chemokines.
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Amiloide , Células Matadoras Naturais , Macrófagos , alfa-Sinucleína , alfa-Sinucleína/metabolismo , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Células Matadoras Naturais/metabolismo , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/efeitos dos fármacos , Humanos , Amiloide/metabolismo , Agregados Proteicos , Animais , Camundongos , Colesterol/metabolismo , Colesterol/química , Fosfatidilserinas/metabolismo , Doença de Parkinson/metabolismo , Neurônios/metabolismo , Endocitose , Proliferação de Células/efeitos dos fármacos , Citocinas/metabolismoRESUMO
Plasmalogens comprise a large fraction of the total phospholipids in plasma membranes. These molecules modulate membrane fluidity, produce inflammatory mediators mitigating effects of metabolic stresses. A growing body of evidence suggests that an onset of Parkinson's disease (PD), a severe neurodegenerative pathology, can be triggered by metabolic changes in plasma membranes. However, the role of plasmalogens in the aggregation of α-synuclein (α-syn), an expected molecular cause of PD, remains unclear. In this study we examine the effect of choline plasmalogens (CPs), unique phospholipids that have a vinyl ether linkage at the sn-1 position of glycerol, on the aggregation rate of α-syn. We found that the length and saturation of fatty acids (FAs) in CPs change rates of protein aggregation. We also found drastic changes in the morphology of α-syn fibrils formed in the presence of different CPs compared to α-syn fibrils grown in the lipid-free environment. At the same time, we did not observe substantial changes in the secondary structure and toxicity of α-syn fibrils formed in the presence of different CPs. These results indicate that the length and saturation of FAs in CPs present in the plasma membrane can alter α-syn stability and modulate its aggregation properties, which, in turn can accelerate or delay the onset of PD.
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Doença de Parkinson , alfa-Sinucleína , Humanos , alfa-Sinucleína/química , Plasmalogênios , Amiloide/química , Doença de Parkinson/metabolismoRESUMO
The discovery of clandestine burials poses unique challenges for forensic specialists, requiring diverse expertise to analyze remains in various states. Bones, teeth, and hair often endure the test of time, with hair particularly exposed to the external environment. While existing studies focus on the degradation of virgin hair influenced by soil pH and decomposition fluids, the interaction between artificial dyes on hair and soil remains underexplored. This paper introduces a novel approach to forensic hair analysis that is based on high-throughput, nondestructive, and non-invasive surface-enhanced Raman spectroscopy (SERS) and machine learning. Using this approach, we investigated the reliability of the detection and identification of artificial dyes on hair buried in three distinct soil types for up to eight weeks. Our results demonstrated that SERS enabled the correct prediction of 97.9% of spectra for five out of the eight dyes used within the 8 weeks of exposure. We also investigated the extent to which SERS and machine learning can be used to predict the number of weeks since burial, as this information may provide valuable insights into post-mortem intervals. We found that SERS enabled highly accurate exposure intervals to soils for specific dyes. The study underscores the high achievability of SERS in extrapolating colorant information from dyed hairs buried in diverse soils, with the suggestion that further model refinement could enhance its reliability in forensic applications.
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Solo , Análise Espectral Raman , Análise Espectral Raman/métodos , Corantes , Reprodutibilidade dos Testes , CabeloRESUMO
Parkinson's disease (PD) is a severe pathology that is caused by a progressive degeneration of dopaminergic neurons in substantia nigra pars compacta as well as other areas in the brain. These neurodegeneration processes are linked to the abrupt aggregation of α-synuclein (α-syn), a small protein that is abundant at presynaptic nerve termini, where it regulates cell vesicle trafficking. Due to the direct interactions of α-syn with cell membranes, a substantial amount of work was done over the past decade to understand the role of lipids in α-syn aggregation. However, the role of phosphatidic acid (PA), a negatively charged phospholipid with a small polar head, remains unclear. In this study, we examined the effect of PA large unilamellar vesicles (LUVs) on α-syn aggregation. We found that PA LUVs with 16:0, 18:0, and 18:1 FAs drastically reduced the toxicity of α-syn fibrils if were present in a 1:1 molar ratio with the protein. Our results also showed that the presence of these vehicles changed the rate of α-syn aggregation and altered the morphology and secondary structure of α-syn fibrils. These results indicate that PA LUVs can be used as a potential therapeutic strategy to reduce the toxicity of α-syn fibrils formed upon PD.
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Doença de Parkinson , alfa-Sinucleína , Humanos , alfa-Sinucleína/metabolismo , Lipossomas Unilamelares/metabolismo , Doença de Parkinson/metabolismo , Neurônios Dopaminérgicos/metabolismoRESUMO
Palmer amaranth (Amaranthus palmeri) is a pervasive and troublesome weed species that poses significant challenges to agriculture in the United States. Identifying the sex of Palmer amaranth plants is crucial for developing tailored control measures due to the distinct characteristics and reproductive strategies exhibited by male and female plants. Traditional methods for sex determination are expensive and time-consuming, but recent advancements in spectroscopic techniques offer new possibilities. This study explores the potential of portable Raman spectroscopy for determining the sex of mature Palmer amaranth plants in-field. Raman analysis of the plant leaves reveals spectral differences associated with nitrate salts, lipids, carotenoids, and terpenoids, allowing for high accuracy and reliable identification of the plant's sex; male plants had higher concentrations of these compounds compared to females. It was also found that male plants had higher concentrations of these compounds compared to the females. Raman spectra were analyzed using a machine learning tool, partial least squares discriminant analysis (PLS-DA), to generate accuracies of no less than 83.7% when elucidating sex from acquired spectra. These findings provide insights into the sex-specific characteristics of Palmer amaranth and suggest that Raman analysis, combined with PLS-DA, can be a promising, non-destructive, and efficient method for sex determination in field settings. This approach has implications for developing sex-specific management strategies to monitor and control this invasive weed in real-world environments, benefiting farmers, agronomists, researchers, and master gardeners.
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BACKGROUND: Ticks and tick-borne diseases pose significant challenges to cattle production, thus the species identification of ticks and knowledge on their presence, abundance, and dispersal are necessary for the development of effective control measures. The standard method of inspection for the presence of ticks is the visual and physical examination of restrained animals, but the limitations of human sight and touch can allow larval, nymphal, and unfed adult ticks to remain undetected due to their small size and site of attachment. However, Raman spectroscopy, an analytical tool widely used in agriculture and other sectors, shows promise for the identification of tick species in infested cattle. Raman spectroscopy is a non-invasive and efficient method that employs the interaction between molecules and light for the identification of the molecular constituents of specimens. METHODS: Raman spectroscopy was employed to analyze the structure and composition of tick feces deposited on host skin and hair during blood-feeding. Feces of 12 species from a total of five genera and one subgenus of ixodid ticks were examined. Spectral data were subjected to partial least squares discriminant analysis, a machine-learning model. We also used Raman spectroscopy and the same analytical procedures to compare and evaluate feces of the horn fly Haematobia irritans after it fed on cattle. RESULTS: Five genera and one sub-genus at overall true prediction rates ranging from 92.3 to 100% were identified from the Raman spectroscopy data of the tick feces. At the species level, Dermacentor albipictus, Dermacentor andersoni and Dermacentor variabilis at overall true prediction rates of 100, 99.3 and 100%, respectively, were identified. There were distinct differences between horn fly and tick feces with respect to blood and guanine vibrational frequencies. The overall true prediction rate for the separation of tick and horn fly feces was 98%. CONCLUSIONS: Our findings highlight the utility of Raman spectroscopy for the reliable identification of tick species from their feces, and its potential application for the identification of ticks from infested cattle in the field.
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Dermacentor , Ixodidae , Infestações por Carrapato , Carrapatos , Humanos , Animais , Bovinos , Análise Espectral Raman , Fezes , Infestações por Carrapato/veterináriaRESUMO
The progressive aggregation of misfolded proteins is the underlying molecular cause of numerous pathologies including Parkinson's disease and injection and transthyretin amyloidosis. A growing body of evidence indicates that protein deposits detected in organs and tissues of patients diagnosed with such pathologies contain fragments of lipid membranes. In vitro experiments also showed that lipid membranes could strongly change the aggregation rate of amyloidogenic proteins, as well as alter the secondary structure and toxicity of oligomers and fibrils formed in their presence. In this review, the effect of large unilamellar vesicles (LUVs) composed of zwitterionic and anionic phospholipids on the aggregation rate of insulin, lysozyme, transthyretin (TTR) and α- synuclein (α-syn) will be discussed. The manuscript will also critically review the most recent findings on the lipid-induced changes in the secondary structure of protein oligomers and fibrils, as well as reveal the extent to which lipids could alter the toxicity of protein aggregates formed in their presence.
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Amiloidose , Doença de Parkinson , Humanos , Agregados Proteicos , Fosfolipídeos/metabolismo , alfa-Sinucleína/química , Doença de Parkinson/metabolismo , Amiloidose/metabolismo , Proteínas Amiloidogênicas , Amiloide/químicaRESUMO
Forensic analysis of fabric is often critically important to establish a relationship between a suspect and a crime scene or demonstrate the absence of such connections. Most of commercially available fabric is colored with primarily organic colorants. These dye substances are highly fluorescent, which limits the use to conventional Raman spectroscopy for the analysis of the colorant content of fabric. At the same time, elucidation of the chemical composition of dyes in fabrics can be used to advance the importance of this physical piece of evidence for forensic research. Our recent findings showed that near-infrared excitation Raman spectroscopy (NIeRS) could be used to overcome this limitation. However, it remains unclear to what extent NIeRS could be used to identify the presence of several different colorants on fabric, as well as utilize for the analysis of dyes on fabric contaminated with paints. In this study, we utilized a hand-held NIeRS instrument to ex-amine re-colored cotton fabric and cotton fabric with household paints applied on it. Our results indicate that NIeRS coupled with chemometrics highly accurately identify the presence of several colorants on cotton. We also found that the presence of paint fully obscures the ability of NIeRS to extract the information about the dye content of the fabric. These results expand our understanding of the use of NIeRS in the forensic analysis of colored fabric.
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Progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta, hypothalamus, and thalamus is a hallmark of Parkinson's disease. Neuronal death is linked to the abrupt aggregation of α-synuclein (α-Syn), a small membrane protein that regulates cell vesicle trafficking. α-Syn aggregation rate, as well as the secondary structure and toxicity of α-Syn fibrils, could be uniquely altered by lipids. However, molecular mechanisms that determine such a remarkable difference in the toxicity of α-Syn fibrils formed in the presence of lipids remain unclear. In this study, we used a set of molecular assays to determine the molecular mechanism by which α-Syn fibrils formed in the presence of phosphatidylcholine (PC), cardiolipin (CL), and cholesterol (Cho) exert cell toxicity. We found that rat dopaminergic cells exposed to α-Syn fibrils formed in the presence of different lipids exert drastically different magnitudes and dynamics of unfolded protein response (UPR) in the endoplasmic reticulum (ER) and mitochondria (MT). Specifically, α-Syn:CL were found to cause the strongest, whereas α-Syn fibrils formed in the absence of lipids had the lowest magnitude of the UPR cell response. We also found the opposite dynamics of the ER- and MT-UPR responses in rat dopaminergic cells exposed to protein aggregates. These results could suggest that facing severe ER stress, dopaminergic cells suppress MT-UPR response, enabling the maximal ATP production to restore their normal physiological function. These findings help to better understand complex mechanisms of cell toxicity of amyloid aggregates and ultimately find neuroprotective drug candidates that will be able to suppress the spread of Parkinson's disease.
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Doença de Parkinson , alfa-Sinucleína , Animais , Ratos , alfa-Sinucleína/metabolismo , Doença de Parkinson/metabolismo , Fosfolipídeos , Agregados Proteicos , ColesterolRESUMO
A progressive aggregation of misfolded proteins is a hallmark of numerous pathologies including diabetes Type 2, Alzheimer's disease, and Parkinson's disease. As a result, highly toxic protein aggregates, which are known as amyloid fibrils, are formed. A growing body of evidence suggests that phospholipids can uniquely alter the secondary structure and toxicity of amyloid aggregates. However, the role of phosphatidic acid (PA), a unique lipid that is responsible for cell signaling and activation of lipid-gated ion channels, in the aggregation of amyloidogenic proteins remains unclear. In this study, we investigate the role of the length and degree of unsaturation of fatty acids (FAs) in PA in the structure and toxicity of lysozyme fibrils formed in the presence of this lipid. We found that both the length and saturation of FAs in PA uniquely altered the secondary structure of lysozyme fibrils. However, these structural differences in PA caused very little if any changes in the morphology of lysozyme fibrils. We also utilized cell toxicity assays to determine the extent to which the length and degree of unsaturation of FAs in PA altered the toxicity of lysozyme fibrils. We found that amyloid fibrils formed in the presence of PA with C18:0 FAs exerted significantly higher cell toxicity compared to the aggregates formed in the presence of PA with C16:0 and C18:1 FAs. These results demonstrated that PA can be an important player in the onset and spread of amyloidogenic diseases.