Sustained PGC-1α2 or PGC-1α3 expression induces astrocyte dysfunction and degeneration

Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) transcriptional coactivators are key regulators of energy metabolism-related genes and are expressed in energy-demanding tissues. There are several PGC-1α variants with different biological functions in different tissues. The brain is one of the tissues where the role of PGC-1α isoforms remains less explored. Here, we used a toxin-based mouse model of Parkinson's disease (PD) and observed that the expression levels of variants PGC-1α2 and PGC-1α3 in the nigrostriatal pathway increases at the onset of dopaminergic cell degeneration. This increase occurs concomitant with an increase in glial fibrillary acidic protein levels. Since PGC-1α coactivators regulate cellular adaptive responses, we hypothesized that they could be involved in the modulation of astrogliosis induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Therefore, we analysed the transcriptome of astrocytes transduced with expression vectors encoding PGC-1α1 to 1α4 by massively parallel sequencing (RNA-seq) and identified the main cellular pathways controlled by these isoforms. Interestingly, in reactive astrocytes the inflammatory and antioxidant responses, adhesion, migration, and viability were altered by PGC-1α2 and PGC-1α3, showing that sustained expression of these isoforms induces astrocyte dysfunction and degeneration. This work highlights PGC-1α isoforms as modulators of astrocyte reactivity and as potential therapeutic targets for the treatment of PD and other neurodegenerative disorders.

Electrodegradation of naphthalenic amines: Influence of the relative position of the substituent groups, anode material and electrolyte on the degradation products and kinetics

The electrodegradation of the 4-aminonaphthalene-1-sulfonic acid (4AN1S), 5-aminonaphthalene-2-sulfonic acid (5AN2S) and 8-aminonaphthalene-2-sulfonic acid (8AN2S) was studied, using two electrode materials as anode, BDD and Ti/Pt/PbO₂, and two different electrolytes, sodium sulfate and sodium chloride. The highest COD removal rates were obtained at BDD: for 5AN2S and 8AN2S results were similar in both electrolytes; for 4AN1S, results were better in sodium chloride. The lowest COD removal rates were obtained at the system Ti/Pt/PbO₂-sodium sulfate, for all the studied amines. The dissolved organic carbon (DOC) removal was much higher at BDD for all the amines, in sulfate for 5AN2S and 8AN2S and in chloride for 4AN1S. Nitrogen removal was always almost irrelevant in sulfate medium but higher than 60%, after 6-h assays, in chloride. The highest combustion efficiencies were attained at the system BDD-sodium sulfate and were: 4AN1S-75%; 5AN2S-84%; 8AN2S-74%. HPLC results show that total degradation of the studied aminonaphthalene sulfonates is attained at both anode materials, utilizing any of the electrolytes, with a first order kinetics. However, kinetic constants obtained with the variation of the amines concentration in time are 10-40 times higher in chloride, being slightly higher at Ti/Pt/PbO₂ than at BDD. Regarding the presence of carboxylic acids during the degradation assays, it was observed that the electrolysis of the amines 5AN2S and 8AN2S always lead to higher amounts of oxalic acid and lower quantities of acetic acid than the electrolysis of the amine 4AN1S.

Preparation, characterization and environmental applications of Sr1 - x (La,Bi) x TiO3 perovskites immobilized on Ni-foam: photodegradation of the Acid Orange 7

The Sr_1 - x La _x TiO₃ (0 ≤ x ≤ 0.4) and Sr_1 - x Bi _x TiO₃ (0 ≤ x ≤ 0.3) perovskites were prepared via solid state reaction by partially replacing the Sr²⁺ ions in the SrTiO₃ structure by La³⁺ or Bi³⁺ ions, characterized and utilized as photocatalysts immobilized in Ni-foam substrate in the degradation of the azo dye Acid Orange 7 (AO7). For both perovskite families, the XRD data reveal the existence of a predominant well-crystallized phase, belonging to a cubic perovskite in a Pm3m space group, with the presence of other minority phases. The characteristic dimension and the volume of the cell decrease with the introduction in the SrTiO₃ lattice of the La³⁺ or Bi³⁺ ions. The grain size of the Sr_1 - x La _x TiO₃ samples is around 100 nm and slightly lower for the Sr_1 - x Bi _x TiO₃ samples. Regarding the utilization of the prepared perovskite powders deposited over the Ni-foam substrates as catalysts in the photodegradation of AO7 solutions, the results show an improvement in the performance of the films of the substituted perovskite when compared to the SrTiO₃ perovskite, being the best results obtained with Sr_0.9Bi_0.1TiO₃.