All trans retinoic acid depresses the content and activity of the mitochondrial ATP synthase in human keratinocytes.

Proteomic analysis shows that treatment of keratinocytes cultures with all trans retinoic acid (ATRA), under condition in which it inhibits cell growth, results in marked decrease of the level of the F1-ß subunit of the catalytic sector of the mitochondrial FoF1 ATP synthase complex. Enzymatic analysis shows in ATRA-treated keratinocytes a consistent depression of the ATPase activity, with decreased olygomycin sensitivity, indicating an overall alteration of the ATP synthase complex. These findings, together with the previously reported inhibition of respiratory complex I, show that depression of the activity of oxidative phosphorylation enzymes is involved in the cell growth inhibitory action of ATRA.

Activation of protein phosphatase 2A is responsible for increased content and inactivation of respiratory chain complex i induced by all-trans retinoic acid in human keratinocytes.

This study presents the effect of all-trans retinoic acid (ATRA) on cell growth and respiratory chain complex I in human keratinocyte cultures. Keratinocyte treatment results in increased level of GRIM-19 and other subunits of complex I, in particular of their carbonylated forms, associated with inhibition of its enzymatic activity. The results show that in keratinocytes ATRA-promoted phosphatase activity controls the proteostasis and activity of complex I.

Periodontal disease and bone pathogenesis: the crosstalk between cytokines and porphyromonas gingivalis

Periodontal disease is the most frequent cause of tooth loss among adults. It is defined as a plaque-induced inflammation of the periodontal tissues that results in a loss of support of the affected teeth. This process is characterized by destruction of the periodontal attachment apparatus, increased bone resorption with loss of crestal alveolar bone, apical migration of the epithelial attachment, and formation of periodontal pockets. Although the presence of periodontal pathogens such as Porphyromonas gingivalis is a prerequisite, the progression of periodontal disease is dependent on the host response to pathogenic bacteria that colonize the tooth surface. Nowadays, a growing body of literature has accumulated to investigate the association between bone diseases, periodontal pathogens and periodontal diseases. The integration of pathogen-associated molecular patterns from microorganisms with their surface receptors in the immune cells, induces the production of several cytokines and chemokines that present either a pro- and/or anti-inflammatory role and the activation of mechanisms of controlling this and the related disease, such as osteoporosis and rheumatoid arthritis. This review focuses on the evidence and significance of bone host cell invasion by Porphyromonas gingivalis in the pathogenesis of bone disorders, as well as the different lines of evidence supporting the role of cytokines in bone diseases.

Induction of mitochondrial dysfunction in patients under cardiopulmonary by-pass: preliminary results.

OBJECTIVE: Cardiac surgery is often performed by cardiopulmonary by-pass (CPB), generally associated with organ dysfunction. The aim of this work was to determine if and how this phenomenon is related to mitochondrial damage. To this purpose, the effect of the addition of serum from CPB patients to human fibroblasts cultures on mitochondrial respiratory chain and oxidative phosphorylation (OXPHOS) activities was investigated. PATIENTS AND METHODS: Serum samples of five patients were obtained before (pre-CPB) and after 6 h CPB weaning (CPB). Mitochondrial OXPHOS activities were examined by polarographic and spectrophotometric assays, and reactive oxygen species (ROS) production was measured by a spectrofluorimeter. RESULTS: Addition of CPB serum to fibroblasts determined a decrease of mitochondrial oxygen consumption due to an inhibition of mitochondrial respiratory chain and some OXPHOS enzymes activities. This inhibition seems to be mainly related to a reduced activity of complex I. CONCLUSIONS: Our data represent the first translational research evidence showing that CPB determines mitochondrial dysfunction which leads to impairment of OXPHOX activities and to an increase in ROS production, compromising tissue bioenergetic efficiency.