جستجوی مقالات مرتبط با کلیدواژه « Neurodegenerative diseases » در نشریات گروه « زیست شناسی »

Transthyretin (TTR)  is a highly conserved 55 kDa homotetrameric protein that exists in several vertebrate species including humans, bacteria, nematodes, and plants. Previous studies have shown a direct interaction between TTR and amyloid beta (Aβ) (the causative agent of Alzheimer's disease), which leads to the inhibition of Aβ aggregation, fibrillar destruction, or both. In recent years, evidence has shown that the oligomeric species of Aβ formed by the aggregation process are more toxic than mature fibrils. Studies have shown that such an oligomeric mediator is modulated by interaction with TTR. However, the exact mechanism of binding of Aβ to TTR has not yet been determined. In this study, after the purification of human transthyretin protein, the inhibitory effects of TTR on the formation of Aβ were shown in different ways, and finally, the role of hydrophobicity interactions in the chaperone activity of TTR was investigated with the help of protein surface hydrophobicity (PSH) measurement studies. The Scatchard diagram for quantitative measurement of PSH indicates an increase in the hydrophobicity of TTR after binding to oligomeric forms of Aβ. The results presented in this research provide insight into the nature and interactions involved in the initial stages of fibril formation in Aβ and its interaction with TTR. The results showed that hydrophobic interactions probably play a role in the binding between TTR and Aβ. Considering the similarity of amyloid formation systems, the described findings of this study can provide a deeper understanding of the pathology of amyloid diseases.

One of the main features of neurodegenerative disorders such as Alzheimer's disease (AD) is the amyloid aggregation of specific proteins in the brain tissue. Inhibition of protein misfolding and aggregation is results of utmost importance in the prevention and treatment of such diseases. In the experimental present study the possible effects of Portulaca oleracea extract on amyloid fibrillation of hen egg white lysozyme (HEWL) as a protein model and possible its role in treatment of amyloidosis diseases were explored. Lysozymal amyloid was prepared in the harsh condition such as acidic pH and high temperature and confirmed by various techniques including Congo red (CR), Thioflavin T (ThT) binding assays and atomic force microscopy. Data were analyzed through SPSS 16 using descriptive statistics as well as independent t-test. The collected and dried Portulaca oleracea was first dechlorophyllized and then its hydroalcoholic extract was obtained. The extract was concentrated and  dried for 48 h, then stored at -20º. This studies by ThT showed that, amyloid formation in the presence of Portulaca oleracea extract significantly (p˂0.05) in a concentration-dependent manner was inhibited. The Amyloid formation inhibition in presence of the extract also were confirmed by Congo red assay and AFM images. Both Intrinsic and ANS fluorescence showed that inhibition effect of the extract is not due to stabilization of native structure of the protein. The results suggested that aromatic compounds in the extract may directly insert into amyloidogenic core of aggregates and disrupt pi-pi stacking interactions and thus inhibit amyloid fibril formation. These results may ultimately find applications in the development of potential inhibitors against amyloid fibril formation and its biologically adverse effects.

Discovering and describing the critical role of proteins in contrast to disease and defects causing by their inactivity is a major interest for scientific studies. Amyloid aggregation and the diseases caused by them, known as neurodegenerative diseases, reveal new aspect of proteins roles in pathogenicity. Due to lack of clear treatment to these age-related diseases, prevention of amyloid formation would be the most practical way to deal with them.

In this research, we analyzed the effects of Heracleum persicum Desf. ex Fisch., C.A.Mey. & Avé-Lall. and Nigella sativa L. alcoholic extracts on insulin amyloid formation. Human insulin (HI) amyloid formation was analyzed under specific pH and temperature conditions by Thioflavin T (ThT) assay and scanning electron microscopy (SEM) while treating with different concentrations of H. persicum and N. sativa alcoholic extracts.

Our results reveal that the alcoholic extracts of H. persicum and N. sativa have significant preventing effects on HI amyloid formation. Considering the long history of these medicinal plant usage in Iranian and Islamic cultures and the presence of antioxidant and anticonvulsant compounds in them, and according to the data obtained from this study, we strongly suggest that these two herbs are suitable candidates as sources of amyloid aggregation prevention compounds.

Neurodegenerative diseases induce apoptosis in neurons by affecting the central nervous system. Glia cells play an important role in preventing the progression of these diseases and increasing neuronal survival. The most important function of glia cells after neuronal survival is the secretion of neuroprotective factors. Neuroprotective factors secreted by astrocytes include TGFβ1, TGFβ2, GDNF, BDNF, and NT3.In this study, we investigate the possible role of vortmanine in the expression of neuroprotective factors BDNF and NT3 secreted by microglia and oligodendrocytes in vitro. For this purpose, cultured microglia and oligodendrocytes were treated with concentrations of 8,12,16 μmol / L for 72 hours.

A 1-2-day-old Wistar rat was used to culture astrocyte cells. Thus, after disinfecting the skin of the body and hands of infants with 70% alcohol-soaked cotton, the infant's head was cut with scissors, the scalp was completely removed and the skull was cut from the neck to the forehead. To reveal the cerebral cortex. The brain was then removed from the skull and placed in Hanks buffer.Concentrations of 8, 12, and 16 mol / L of vortmanine are added by sampler to microglia and oligodendrocyte cells cultured in 6-well plates and The expression of neuroprotective factors was measured by R-T PCR

Vertmanine-treated astrocyte cells showed significant morphological changes.However, morphological changes were much less observed in control cells compared to treated cells.