title: The Cratylia mollis seed lectin induces membrane permeability transition in isolated rat liver mitochondria and a cyclosporine a-insensitive permeability transition in Trypanosoma cruzi mitochondria.
abstract: Previous results provided evidence that Cratylia mollis seed lectin (Cramoll 1,4) promotes Trypanosoma cruzi epimastigotes death by necrosis via a mechanism involving plasma membrane permeabilization to Ca(2+) and mitochondrial dysfunction due to matrix Ca(2+) overload. In order to investigate the mechanism of Ca(2+) -induced mitochondrial impairment, experiments were performed analyzing the effects of this lectin on T. cruzi mitochondrial fraction and in isolated rat liver mitochondria (RLM), as a control. Confocal microscopy of T. cruzi whole cell revealed that Cramoll 1,4 binding to the plasma membrane glycoconjugates is followed by its internalization and binding to the mitochondrion. Electrical membrane potential (∆Ψm ) of T. cruzi mitochondrial fraction suspended in a reaction medium containing 10 μM Ca(2+) was significantly decreased by 50 μg/ml Cramoll 1,4 via a mechanism insensitive to cyclosporine A (CsA, membrane permeability transition (MPT) inhibitor), but sensitive to catalase or 125 mM glucose. In RLM suspended in a medium containing 10 μM Ca(2+) this lectin, at 50 μg/ml, induced increase in the rate of hydrogen peroxide release, mitochondrial swelling, and ∆Ψm disruption. All these mitochondrial alterations were sensitive to CsA, catalase, and EGTA. These results indicate that Cramoll 1, 4 leads to inner mitochondrial membrane permeabilization through Ca(2+) dependent mechanisms in both mitochondria. The sensitivity to CsA in RLM characterizes this lectin as a MPT inducer and the lack of CsA effect identifies a CsA-insensitive MPT in T. cruzi mitochondria.
authors.affiliation: Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil.
authors.forename: Mariana P
authors.initials: MP
authors.lastname: Fernandes
authors.forename: Ana C R
authors.initials: AC
authors.lastname: Leite
authors.forename: Flavia F B
authors.initials: FF
authors.lastname: Araújo
authors.forename: Sara T O
authors.initials: ST
authors.lastname: Saad
authors.forename: M O
authors.initials: MO
authors.lastname: Baratti
authors.forename: M T S
authors.initials: MT
authors.lastname: Correia
authors.forename: Luana C B B
authors.initials: LC
authors.lastname: Coelho
authors.forename: Fernanda R
authors.initials: FR
authors.lastname: Gadelha
authors.forename: Anibal E
authors.initials: AE
authors.lastname: Vercesi
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D016572:Cyclosporine / Q000494:pharmacology*; D007887:Fabaceae / Q000737:chemistry*; D037102:Lectins / Q000494:pharmacology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D012639:Seeds / Q000737:chemistry*; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000378:metabolism
chemical_list: D037102:Lectins; D017382:Reactive Oxygen Species; D016572:Cyclosporine; D002118:Calcium
keywords: Calcium; Cramoll 1,4; ROS; mitochondrial permeability transition