An endosymbiont positively modulates ornithine decarboxylase in host trypanosomatids
Mariana Lins Frossard1, Sergio Henrique Seabra1, Renato Augusto DaMatta2, Wanderley de Souza1, Fernando Garcia de Mello3 and Maria Cristina Machado Motta1
1Laboratório de Ultraestrutura Celular Hertha Meyer Instituto de Biofísica Carlos Chagas Filho - UFRJ, 2Laboratório de Biologia Celular e Tecidual, Centro de Biociências e Biotecnologia – UENF, 3Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho - UFRJ
Some trypanosomatids, such as Crithidia deanei, are endosymbiont-containing species. Aposymbiotic strains are obtained after antibiotic treatment, revealing interesting aspects of this symbiotic association. Ornithine decarboxylase (ODC) promotes polyamine biosynthesis and contributes to cell proliferation. Here, we show that ODC activity is higher in endosymbiont-bearing trypanosomatids than in aposymbiotic cells, but isolated endosymbionts did not display this enzyme activity. Intriguingly, expressed levels of ODC were similar in both strains, suggesting that ODC is positively modulated in endosymbiont-bearing cells. When the aposymbiotic strain was grown in conditioned medium, obtained after cultivation of the endosymbiont-bearing strain, cellular proliferation, as well as ODC activity and localization, were similar to that observed in the endosymbiont-containing trypanosomatids. Furthermore, dialysed-heated medium and trypsin treatment reduced ODC activity of the aposymbiont strain. Taken together, these data indicate that the endosymbiont can enhance the protozoan ODC activity by providing factors of protein nature, which increase the host polyamine metabolism.
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