Jennifer Baraka-Vidot1, Giovanna Navarra2, Maurizio Leone3, Emmanuel Bourdon1, Valeria Militello3, Philippe Rondeau4. 1. Groupe d'Etude sur l'Inflammation Chronique et l'Obésité (GEICO) EA 4516, Université de La Réunion, Faculté des Sciences, 15 avenue R. Cassin, BP 7151, 97715, Saint Denis Cedex and Plateforme CYROI, 2 Rue Maxime Rivière, BP 80 005, 97491 Sainte Clotilde Cedex, Reunion Island, France. 2. Università di Palermo, Dipartimento di Fisica e Chimica, Via Archirafi 36, Palermo, Italy. Electronic address: giovanna.navarra@unipa.it. 3. Università di Palermo, Dipartimento di Fisica e Chimica, Via Archirafi 36, Palermo, Italy; Consiglio Nazionale delle Ricerche, Istituto di Biofisica, Via Ugo La Malfa 136, Palermo, Italy. 4. Groupe d'Etude sur l'Inflammation Chronique et l'Obésité (GEICO) EA 4516, Université de La Réunion, Faculté des Sciences, 15 avenue R. Cassin, BP 7151, 97715, Saint Denis Cedex and Plateforme CYROI, 2 Rue Maxime Rivière, BP 80 005, 97491 Sainte Clotilde Cedex, Reunion Island, France. Electronic address: rophil@univ-reunion.fr.
Abstract
BACKGROUND: Metal ions such as copper or zinc are involved in the development of neurodegenerative pathologies and metabolic diseases such as diabetes mellitus. Albumin structure and functions are impaired following metal- and glucose-mediated oxidative alterations. The aim of this study was to elucidate effects of Cu(II) and Zn(II) ions on glucose-induced modifications in albumin by focusing on glycation, aggregation, oxidation and functional aspects. METHODS: Aggregation and conformational changes in albumin were monitored by spectroscopy, fluorescence and microscopy techniques. Biochemical assays such as carbonyl, thiol groups, albumin-bound Cu, fructosamine and amine group measurements were used. Cellular assays were used to gain functional information concerning antioxidant activity of oxidized albumins. RESULTS: Both metals promoted inhibition of albumin glycation associated with an enhanced aggregation and oxidation process. Metal ions gave rise to the formation of β-amyloid type aggregates in albumin exhibiting impaired antioxidant properties and toxic activity to murine microglia cells (BV2). The differential efficiency of both metal ions to inhibit albumin glycation, to promote aggregation and to affect cellular physiology is compared. CONCLUSIONS AND GENERAL SIGNIFICANCE: Considering the key role of oxidized protein in pathology complications, glycation-mediated and metal ion-induced impairment of albumin properties might be important parameters to be followed and fought.
BACKGROUND:Metal ions such as copper or zinc are involved in the development of neurodegenerative pathologies and metabolic diseases such as diabetes mellitus. Albumin structure and functions are impaired following metal- and glucose-mediated oxidative alterations. The aim of this study was to elucidate effects of Cu(II) and Zn(II) ions on glucose-induced modifications in albumin by focusing on glycation, aggregation, oxidation and functional aspects. METHODS: Aggregation and conformational changes in albumin were monitored by spectroscopy, fluorescence and microscopy techniques. Biochemical assays such as carbonyl, thiol groups, albumin-bound Cu, fructosamine and amine group measurements were used. Cellular assays were used to gain functional information concerning antioxidant activity of oxidized albumins. RESULTS: Both metals promoted inhibition of albumin glycation associated with an enhanced aggregation and oxidation process. Metal ions gave rise to the formation of β-amyloid type aggregates in albumin exhibiting impaired antioxidant properties and toxic activity to murine microglia cells (BV2). The differential efficiency of both metal ions to inhibit albumin glycation, to promote aggregation and to affect cellular physiology is compared. CONCLUSIONS AND GENERAL SIGNIFICANCE: Considering the key role of oxidized protein in pathology complications, glycation-mediated and metal ion-induced impairment of albumin properties might be important parameters to be followed and fought.