RESUMEN
Sialic acids and heparan sulfates make up the outermost part of the cell membrane and the extracellular matrix. Both structures are characterized by being negatively charged, serving as receptors for various pathogens, and are highly expressed in the respiratory and digestive tracts. Numerous viruses use heparan sulfates as receptors to infect cells; in this group are HSV, HPV, and SARS-CoV-2. Other viruses require the cell to express sialic acids, as is the case in influenza A viruses and adenoviruses. This review aims to present, in a general way, the participation of glycoconjugates in viral entry, and therapeutic strategies focused on inhibiting the interaction between the virus and the glycoconjugates. Interestingly, there are few studies that suggest the participation of both glycoconjugates in the viruses addressed here. Considering the biological redundancy that exists between heparan sulfates and sialic acids, we propose that it is important to jointly evaluate and design strategies that contemplate inhibiting the interactions of both glycoconjugates. This approach will allow identifying new receptors and lead to a deeper understanding of interspecies transmission.
Asunto(s)
COVID-19 , Virus , Glicoconjugados/metabolismo , Heparitina Sulfato/metabolismo , Humanos , Ácido N-Acetilneuramínico/metabolismo , Receptores Virales/metabolismo , SARS-CoV-2 , Ácidos Siálicos/metabolismo , Sulfatos , Acoplamiento Viral , Virus/metabolismoRESUMEN
Glycosaminoglycans (GAGs), including heparan sulfates and chondroitin sulfates, are major components of the extracellular matrix. Upon interacting with heparin binding growth factors (HBGF), GAGs participate to the maintaintenance of tissue homeostasis and contribute to self-healing. Although several processes regulated by HBGF are altered in Alzheimer's disease, it is unknown whether the brain GAG capacities to bind and regulate the function of HBGF or of other heparin binding proteins, as tau, are modified in this disease. Here, we show that total sulfated GAGs from hippocampus of Alzheimer's disease have altered capacities to bind and potentiate the activities of growth factors including FGF-2, VEGF, and BDNF while their capacity to bind to tau is remarkable increased. Alterations of GAG structures and capacities to interact with and regulate the activity of heparin binding proteins might contribute to impaired tissue homeostasis in the Alzheimer's disease brain.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Glicosaminoglicanos/metabolismo , Proteínas tau/fisiología , Anciano , Anciano de 80 o más Años , Encéfalo/metabolismo , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Brasil , Sulfatos de Condroitina/metabolismo , Matriz Extracelular/metabolismo , Femenino , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Heparina/metabolismo , Heparitina Sulfato/metabolismo , Hipocampo/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Unión Proteica , Lóbulo Temporal/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Synucleinophaties are progressive neurodegenerative disorders with no cure to date. An attractive strategy to tackle this problem is repurposing already tested safe drugs against novel targets. In this way, doxycycline prevents neurodegeneration in Parkinson models by modulating neuroinflammation. However, anti-inflammatory therapy per se is insufficient to account for neuroprotection. Herein we characterise novel targets of doxycycline describing the structural background supporting its effectiveness as a neuroprotector at subantibiotic doses. Our results show that doxycycline reshapes α-synuclein oligomers into off-pathway, high-molecular-weight species that do not evolve into fibrils. Off-pathway species present less hydrophobic surface than on-pathway oligomers and display different ß-sheet structural arrangement. These structural changes affect the α-synuclein ability to destabilize biological membranes, cell viability, and formation of additional toxic species. Altogether, these mechanisms could act synergically giving novel targets for repurposing this drug.
Asunto(s)
Doxiciclina/farmacología , Reposicionamiento de Medicamentos , Enfermedades Neurodegenerativas/metabolismo , alfa-Sinucleína/metabolismo , Línea Celular Tumoral , Supervivencia Celular , Doxiciclina/uso terapéutico , Humanos , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Enfermedades Neurodegenerativas/tratamiento farmacológico , Enfermedades Neurodegenerativas/patología , Agregado de Proteínas/efectos de los fármacos , Agregación Patológica de Proteínas , Unión Proteica , Conformación Proteica en Lámina beta , Multimerización de Proteína , Espectroscopía Infrarroja por Transformada de Fourier , alfa-Sinucleína/químicaRESUMEN
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional enzyme that has been associated with neurodegenerative diseases. GAPDH colocalizes with α-synuclein in amyloid aggregates in post-mortem tissue of patients with sporadic Parkinson disease and promotes the formation of Lewy body-like inclusions in cell culture. In a previous work, we showed that glycosaminoglycan-induced GAPDH prefibrillar species accelerate the conversion of α-synuclein to fibrils. However, it remains to be determined whether the interplay among glycosaminoglycans, GAPDH, and α-synuclein has a role in pathological states. Here, we demonstrate that the toxic effect exerted by α-synuclein oligomers in dopaminergic cell culture is abolished in the presence of GAPDH prefibrillar species. Structural analysis of prefibrillar GAPDH performed by small angle x-ray scattering showed a particle compatible with a protofibril. This protofibril is shaped as a cylinder 22 nm long and a cross-section diameter of 12 nm. Using biocomputational techniques, we obtained the first all-atom model of the GAPDH protofibril, which was validated by cross-linking coupled to mass spectrometry experiments. Because GAPDH can be secreted outside the cell where glycosaminoglycans are present, it seems plausible that GAPDH protofibrils could be assembled in the extracellular space kidnapping α-synuclein toxic oligomers. Thus, the role of GAPDH protofibrils in neuronal proteostasis must be considered. The data reported here could open alternative ways in the development of therapeutic strategies against synucleinopathies like Parkinson disease.
Asunto(s)
Gliceraldehído-3-Fosfato Deshidrogenasas/química , Gliceraldehído-3-Fosfato Deshidrogenasas/farmacología , Heparina/farmacología , Multimerización de Proteína/efectos de los fármacos , alfa-Sinucleína/química , alfa-Sinucleína/toxicidad , Secuencia de Aminoácidos , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Reactivos de Enlaces Cruzados/farmacología , Humanos , Modelos Moleculares , Datos de Secuencia Molecular , Neuronas/citología , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/farmacología , Estructura Secundaria de ProteínaRESUMEN
Lewy bodies and Lewy neurites, neuropathological hallmarks of several neurological diseases, are mainly made of filamentous assemblies of α-synuclein. However, other macromolecules including Tau, ubiquitin, glyceraldehyde-3-phosphate dehydrogenase, and glycosaminoglycans are routinely found associated with these amyloid deposits. Glyceraldehyde-3-phosphate dehydrogenase is a glycolytic enzyme that can form fibrillar aggregates in the presence of acidic membranes, but its role in Parkinson disease is still unknown. In this work, the ability of heparin to trigger the amyloid aggregation of this protein at physiological conditions of pH and temperature is demonstrated by infrared and fluorescence spectroscopy, dynamic light scattering, small angle x-ray scattering, circular dichroism, and fluorescence microscopy. Aggregation proceeds through the formation of short rod-like oligomers, which elongates in one dimension. Heparan sulfate was also capable of inducing glyceraldehyde-3-phosphate dehydrogenase aggregation, but chondroitin sulfates A, B, and C together with dextran sulfate had a negligible effect. Aided with molecular docking simulations, a putative binding site on the protein is proposed providing a rational explanation for the structural specificity of heparin and heparan sulfate. Finally, it is demonstrated that in vitro the early oligomers present in the glyceraldehyde-3-phosphate dehydrogenase fibrillation pathway promote α-synuclein aggregation. Taking into account the toxicity of α-synuclein prefibrillar species, the heparin-induced glyceraldehyde-3-phosphate dehydrogenase early oligomers might come in useful as a novel therapeutic strategy in Parkinson disease and other synucleinopathies.