Banca de QUALIFICAÇÃO: ALESSANDRA MARINHO MIRANDA LUCENA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ALESSANDRA MARINHO MIRANDA LUCENA
DATE: 01/10/2024
TIME: 08:30
LOCAL: Videoconferência - Link para acesso: https://meet.google.com/yap-svwa-wwj
TITLE:

Evaluation of the Neuroprotective Effect of Sulfated Polysaccharides on Nerve Tissue Cells in vitro

KEY WORDS:

SEAWEED, BIOACTIVITY, ANTIOXIDANT, NEUROPROTECTION

PAGES: 120
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUMMARY:

Marine algae are sources of valuable products for food, industrial, pharmaceutical, and nutraceutical markets, with an emphasis on sulfated polysaccharides (SP). These compounds are crucial for algal survival and possess significant biological activities, such as antioxidant and anti-inflammatory properties. Such properties may be useful in treating neurodegenerative diseases, like Alzheimer’s and Parkinson’s, due to the role of oxidative stress in the development of these conditions. With increasing life expectancy and the projected growth of dementia-related conditions, there is a growing need for new treatments. Algal SP have shown promise as a neuroprotective alternative. However, SP from tropical algae have not yet been evaluated in this context. Thus, following a bibliographic search of 100 tropical algae species, 9 species were identified whose SP exhibit antioxidant activity under various conditions. Of the 43 SP-rich fractions (PRF) obtained from these algae, 42 PRF showed no cytotoxicity against Neuro-2A cells in at least one of the evaluated concentrations (0.1, 0.25, 0.5, or 1 mg/mL). All evaluated algae had PRF that protected Neuro-2A cells from hydrogen peroxide-induced oxidative damage. Considering the results of yield parameters, cytotoxic effect, and neuroprotective potential in cell culture, it was possible to observe that brown algae had the best results. Based on these data, 4 PRF (DJ 1.2, SF 0.5, SS 1.3, and DM 1.0) were selected to evaluate the possible mechanisms involved. The analysis of the hydrogen peroxide sequestration potential, the effect on gene expression of the antioxidant pathway (Keap1, Nfr2, Sod1, Cat, Gpx, Hmox1, Gclc, and Gclm), and the subunits of the transcription factor NFκβ (Nfkb1 and Rela), and the antioxidant protection capacity using an in vivo model (Zebrafish) were performed. The data obtained here demonstrate that the mechanisms used by these samples range from direct action on oxidizing molecules, as they are able to sequester H2O2, to the modulation of endogenous antioxidant mechanisms, promoting an increase in the expression of genes related to the translation of antioxidant enzymes (SOD, CAT, GCLC, GCLM, GPx, and HO-1) and a reduction in the expression of the Rela gene (NFκβ P65), which is related to a pro-inflammatory and pro-oxidant response. In addition, these polysaccharides were able to promote protection against oxidative stress in a more complex biological system. These data are important for the development of future evaluations of these molecules, as they have provided knowledge about their potential neuroprotective effect and antioxidant activity, thus giving direction to the possible mechanisms involved.

COMMITTEE MEMBERS:
Presidente - 2195251 - HUGO ALEXANDRE DE OLIVEIRA ROCHA
Externa ao Programa - 1346635 - JANEUSA TRINDADE DE SOUTO - nullExterno ao Programa - 3060683 - LEONARDO THIAGO DUARTE BARRETO NOBRE - nullExterno à Instituição - WESLLEY DE SOUZA PAIVA - UFRN