Avenanthramide-C prevents amyloid formation of bovine serum albumin.

The misfolding of protein and its assembly into amyloid fibrils with a characteristic ß-sheet-rich secondary structure, cause a lot of illnesses. Polyphenols have been extensively studied as a class of amyloid inhibitors, whose effect depends on the position and number of hydroxyl groups around the flavone backbone. In this study, we used bovine serum albumin (BSA) as an amyloid model to test the anti-amyloid effects of Avenanthramide-C (Avn-C), a molecule with a long aliphatic linker between two aromatic rings. We used spectroscopy techniques like thioflavin T fluorescence and circular dichroism, to follow the ß-sheet-rich aggregates of BSA upon incubation at 68 °C. Our results demonstrated that Avn-C shows higher inhibitory effect on BSA oligomerization at micromolar concentrations, than Epigallocatechin gallate (EGCG) and Curcumin, proving for the first time, that Avn-C can serve as potential molecule in preventing protein aggregation.

Maternal Flavonoids Intake Reverts Depression-Like Behaviour in Rat Female Offspring.

Maternal hypercaloric exposure during pregnancy and lactation is a risk factor for developing diseases associated with inflammation such as obesity, diabetes and, neurological diseases in the offspring. Neuroinflammation might modulate neuronal activation and flavonoids are dietary compounds that have been proven to exert anti-inflammatory properties. Thus, the aim of the present study is to evaluate the effect of maternal supplementation with flavonoids (kaempferol-3-O-glucoside and narirutin) on the prevention of depression-like behaviour in the female offspring of dams fed with an obesogenic diet during the perinatal period. Maternal programming was induced by high fat (HFD), high sugar (HSD), or cafeteria diets exposure and depressive like-behaviour, referred to as swimming, climbing, and immobility events, was evaluated around postnatal day 56⁻60 before and after 30 mg/kg i.p. imipramine administration in the female offspring groups. Central inflammation was analyzed by measuring the TANK binding kinase 1 (TBK1) expression. We found that the offspring of mothers exposed to HSD programming failed to show the expected antidepressant effect of imipramine. Also, imipramine injection, to the offspring of mothers exposed to cafeteria diet, displayed a pro-depressive like-behaviour phenotype. However, dietary supplementation with flavonoids reverted the depression-like behaviour in the female offspring. Finally, we found that HSD programming increases the TBK1 inflammatory protein marker in the hippocampus. Our data suggest that maternal HSD programming disrupts the antidepressant effect of imipramine whereas cafeteria diet exposure leads to depressive-like behaviour in female offspring, which is reverted by maternal flavonoid supplementation.

Análisis funcional de oligómeros de alfa-sinucleína en la permeabilidad de membranas / Functional analysis of oligomeric alpha-synuclein in membrane permeabilization / Análise funcional dos oligômeros de alfa-sinucleína na permeabilidade das membranas

La enfermedad de Parkinson es un desorden neurodegenerativo común originado por la muerte celular dentro de la substancia nigra pars compacta. Se caracteriza por la presencia de agregados intracelulares proteicos compuestos principalmente por la alfa-sinucleína. Aunque los mecanismos moleculares por los cuales esta proteína contribuye a la toxicidad neuronal todavía se desconocen, se ha sugerido que los intermediarios oligoméricos son citotóxicos y permeabilizan las membranas celulares posiblemente a través de complejos que forman un poro en la bicapa; sin embargo, este mecanismo es altamente controversial. Así pues es necesario identificar el mecanismo por el cual ocurre la permeabilización de membranas para entender la interacción entre oligómeros y lípidos y poder estimar la relevancia biológica de este proceso.En este trabajo se evaluó por espectroscopía de fluorescencia la liberación de contenidos acuosos originados por oligómeros de alfa-sinucleína desde vesículas fosfolipídicas de distinta composición mediante el método ANTS/DPX. Los resultados muestran que la disrupción de membranas solo ocurre en presencia de lípidos aniónicos y también por parámetros de empaquetamiento lipídico, lo que sugiere que la accesibilidad a la región hidrofóbica de las vesículas modula la interacción lípido-oligómero.

Parkinson's disease is a common neurodegenerative disorder marked by increased cell death within the substantia nigra pars compacta. It is characterized by the presence of intracellular aggregates composed primarily of the protein alpha-synuclein. How the aggregation of a-synuclein is related to neuronal degeneration is an important unresolved question. Oligomeric intermediates have been found to be more toxic to cells than monomeric or fibrillar forms of the protein. A possible mechanism by which oligomers could be toxic is through the disruption and permeabilization of cellular membranes. The proposed disruption mechanism is the formation of pore-like structures within the lipid bilayer although this mechanism is still highly controversial. To identify the mechanism through which membrane permeabilization is facilitated and to estimate the biological relevance of this process, it is crucial to have a greater knowledge of the lipid-oligomer interaction. The membrane disruptive effect of Alpha-synuclein oligomers on lipid vesicles of different headgroup composition using the ANTS/DPX assay was evaluated in this work. It was shown that membrane permeabilization is mainly determined by the presence of negatively charged lipids and also by lipid packing parameters, suggesting that the accessibility to the bilayer hydrocarbon core modulates oligomer-membrane interaction.

pars compacta. é caracterizada pela presença de agregados intracelulares protéicos compostos especialmente pela alfa-sinucleína.Mesmo que se desconheça os mecanismos moleculares por onde essa proteína contribui para toxicidade neuronal, existe uma possibilidade de que os intermediários oligoméricos sejam citotóxicos, e permeabilizam as membranas celulares possivelmente através de complexos que formam um poro na capa dupla, entretanto, este mecanismo gera muita controvérsia. Sendo assim, é necessário identificar o mecanismo responsável pela permeabilidade das membranas para entender a interação entre os oligômeros e os lipídios, e para ter uma estimativa da relevância biológica deste processo. Neste trabalho, analisamos através de espectroscopia de fluorescência, a liberação dos conteúdos aquoso originados por oligômeros de alfa-sinucleína a partir das vesículas fosfolídicas de composição diferente através do método ANTS/DPX. Os resultados mostraram que a ruptura de membranas ocorrerá somente diante da presença de lipídios aniônicos, e também pelos parâmetros de empacotamento lipídico, e isso sugere que a acessibilidade à região hidrofóbica das vesículas faz a modulação da interação lípidio-oligômero.

Análisis funcional de oligómeros de alfa-sinucleína en la permeabilidad de membranas / Functional analysis of oligomeric alpha-synuclein in membrane permeabilization / Análise funcional dos olig¶meros de alfa-sinucleína na permeabilidade das membranas

La enfermedad de Parkinson es un desorden neurodegenerativo común originado por la muerte celular dentro de la substancia nigra pars compacta. Se caracteriza por la presencia de agregados intracelulares proteicos compuestos principalmente por la alfa-sinucleína. Aunque los mecanismos moleculares por los cuales esta proteína contribuye a la toxicidad neuronal todavía se desconocen, se ha sugerido que los intermediarios oligoméricos son citotóxicos y permeabilizan las membranas celulares posiblemente a través de complejos que forman un poro en la bicapa; sin embargo, este mecanismo es altamente controversial. Así pues es necesario identificar el mecanismo por el cual ocurre la permeabilización de membranas para entender la interacción entre oligómeros y lípidos y poder estimar la relevancia biológica de este proceso. En este trabajo se evaluó por espectroscopía de fluorescencia la liberación de contenidos acuosos originados por oligómeros de alfa-sinucleína desde vesículas fosfolipídicas de distinta composición mediante el método ANTS/ DPX. Los resultados muestran que la disrupción de membranas solo ocurre en presencia de lípidos aniónicos y también por parámetros de empaquetamiento lipídico, lo que sugiere que la accesibilidad a la región hidrofóbica de las vesículas modula la interacción lípido-oligómero.(AU)

Parkinsons disease is a common neurodegenerative disorder marked by increased cell death within the substantia nigra pars compacta. It is characterized by the presence of intracellular aggregates composed primarily of the protein alpha-synuclein. How the aggregation of a-synuclein is related to neuronal degeneration is an important unresolved question. Oligomeric intermediates have been found to be more toxic to cells than monomeric or fibrillar forms of the protein. A possible mechanism by which oligomers could be toxic is through the disruption and permeabilization of cellular membranes. The proposed disruption mechanism is the formation of pore-like structures within the lipid bilayer although this mechanism is still highly controversial. To identify the mechanism through which membrane permeabilization is facilitated and to estimate the biological relevance of this process, it is crucial to have a greater knowledge of the lipid-oligomer interaction. The membrane disruptive effect of Alpha-synuclein oligomers on lipid vesicles of different headgroup composition using the ANTS/DPX assay was evaluated in this work. It was shown that membrane permeabilization is mainly determined by the presence of negatively charged lipids and also by lipid packing parameters, suggesting that the accessibility to the bilayer hydrocarbon core modulates oligomer-membrane interaction.(AU)

A doenþa de Parkinson é uma condiþÒo neuro-degenerativa comum que se origina na morte celular dentro da substÔncia nigra pars compacta. é caracterizada pela presenþa de agregados intracelulares protéicos compostos especialmente pela alfa-sinucleína.Mesmo que se desconheþa os mecanismos moleculares por onde essa proteína contribui para toxicidade neuronal, existe uma possibilidade de que os intermediários oligoméricos sejam citotóxicos, e permeabilizam as membranas celulares possivelmente através de complexos que formam um poro na capa dupla, entretanto, este mecanismo gera muita controvérsia. Sendo assim, é necessário identificar o mecanismo responsável pela permeabilidade das membranas para entender a interaþÒo entre os olig¶meros e os lipídios, e para ter uma estimativa da relevÔncia biológica deste processo. Neste trabalho, analisamos através de espectroscopia de fluorescÛncia, a liberaþÒo dos conteúdos aquoso originados por olig¶meros de alfa-sinucleína a partir das vesículas fosfolídicas de composiþÒo diferente através do método ANTS/DPX. Os resultados mostraram que a ruptura de membranas ocorrerá somente diante da presenþa de lipídios ani¶nicos, e também pelos parÔmetros de empacotamento lipídico, e isso sugere que a acessibilidade O regiÒo hidrofóbica das vesículas faz a modulaþÒo da interaþÒo lípidio-olig¶mero.(AU)