Alteration of mitochondrial supercomplexes assembly in metabolic diseases.

Deregulation of nutrient, hormonal, or neuronal signaling produces metabolic alterations that result in increased mitochondrial reactive oxygen species (ROS) production. The associations of the mitochondrial respiratory chain components into supercomplexes could have pathophysiological relevance in metabolic diseases, as supramolecular arrangements, by sustaining a high electron transport rate, might prevent ROS generation. In this review, the relationship between mitochondrial dysfunction and supercomplex arrangement of the mitochondrial respiratory chain components in obesity, insulin resistance, hepatic steatosis and diabetes mellitus is summarized and discussed.

Cytogenetic effects of Jacareubin from Calophyllum brasiliense on human peripheral blood mononucleated cells in vitro and on mouse polychromatic erythrocytes in vivo.

Jacareubin is a xanthone isolated from the heartwood of Calophyllum brasiliense with antibacterial and gastroprotective properties and the intention for clinical use as an anti-cancer treatment (due to the similar chemical structure to other anti-neoplastic drugs) requires an investigation of whether this compound can generate adverse effects on non-transformed cells. Jacareubin (0.5-1000µM in DMSO) was more cytotoxic on phytohemagglutinin (PHA)-stimulated normal human peripheral blood mononuclear cells (PBMCs; IC50 at 72h by MTT: 85.9µM) than on G0 phase-PBMCs (IC50 315.6µM) using trypan blue exclusion and formazan metabolism assays. Jacareubin had lower toxicity on PBMCs than Taxol (1µM). Jacareubin presented cytostatic activity because it inhibited PHA-stimulated PBMCs proliferation (from 2.5µM; CFSE dilution and replication index). Jacareubin induced PBMCs arrest in G0/G1 phase of the cell cycle (from 5µM) as evaluated by DNA content. Moreover, Jacareubin generated genotoxicity by breaking DNA strands selectively in PHA-stimulated PBMCs (from 5µM) rather than on resting PBMCs using the single-cell gel electrophoresis assay and increasing the frequency of micronucleated (MN) PBMCs in vitro (from 5µM) and frequency of hypodiploid cells (from 10µM). When 100mg/kg Jacareubin was injected i.p. into mice (a fifth of the LD50; 0.548g/kg. Approximately to 300µM in vitro), we observe no increase in the MN level in bone marrow cells. Jacareubin can be consider for further anti-tumoural activity due to its preferential genotoxic, cytotoxic and cytostatic actions on proliferating cells rather than on resting cells and the lack of in vivo genotoxicity.

Curcumin prevents maleate-induced nephrotoxicity: relation to hemodynamic alterations, oxidative stress, mitochondrial oxygen consumption and activity of respiratory complex I.

The potential protective effect of the dietary antioxidant curcumin (120 mg/Kg/day for 6 days) against the renal injury induced by maleate was evaluated. Tubular proteinuria and oxidative stress were induced by a single injection of maleate (400 mg/kg) in rats. Maleate-induced renal injury included increase in renal vascular resistance and in the urinary excretion of total protein, glucose, sodium, neutrophil gelatinase-associated lipocalin (NGAL) and N-acetyl ß-D-glucosaminidase (NAG), upregulation of kidney injury molecule (KIM)-1, decrease in renal blood flow and claudin-2 expression besides of necrosis and apoptosis of tubular cells on 24 h. Oxidative stress was determined by measuring the oxidation of lipids and proteins and diminution in renal Nrf2 levels. Studies were also conducted in renal epithelial LLC-PK1 cells and in mitochondria isolated from kidneys of all the experimental groups. Maleate induced cell damage and reactive oxygen species (ROS) production in LLC-PK1 cells in culture. In addition, maleate treatment reduced oxygen consumption in ADP-stimulated mitochondria and diminished respiratory control index when using malate/glutamate as substrate. The activities of both complex I and aconitase were also diminished. All the above-described alterations were prevented by curcumin. It is concluded that curcumin is able to attenuate in vivo maleate-induced nephropathy and in vitro cell damage. The in vivo protection was associated to the prevention of oxidative stress and preservation of mitochondrial oxygen consumption and activity of respiratory complex I, and the in vitro protection was associated to the prevention of ROS production.