title: Heme requirement and intracellular trafficking in Trypanosoma cruzi epimastigotes.
abstract: Epimastigotes multiplies in the insect midgut by taking up nutrients present in the blood meal including heme bound to hemoglobin of red blood cell. During blood meal digestion by vector proteases in the posterior midgut, hemoglobin is clipped off into amino acids, peptides, and free heme. In this paper, we compared the heme and hemoglobin uptake kinetics and followed their intracellular trafficking. Addition of heme to culture medium increased epimastigote proliferation in a dose-dependent manner, while medium supplemented with hemoglobin enhanced growth after 3-day lag phase. Medium supplemented with globin-derived peptides stimulated cell proliferation in a dose-independent way. Using Palladium mesoporphyrin IX (Pd-mP) as a fluorescent heme-analog, we observed that heme internalization proceeded much faster than that observed by hemoglobin-rhodamine. Binding experiments showed that parasites accumulated the Pd-mP into the posterior region of the cell whereas hemoglobin-rhodamine stained the anterior region. Finally, using different specific inhibitors of ABC transporters we conclude that a P-glycoprotein homologue transporter is probably involved in heme transport through the plasma membrane.
authors.affiliation: Lab. de Bioquímica de Artrópodes Hematófagos, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: F A
authors.initials: FA
authors.lastname: Lara
authors.forename: C
authors.initials: C
authors.lastname: Sant'anna
authors.forename: D
authors.initials: D
authors.lastname: Lemos
authors.forename: G A T
authors.initials: GA
authors.lastname: Laranja
authors.forename: M G P
authors.initials: MG
authors.lastname: Coelho
authors.forename: I
authors.initials: I
authors.lastname: Reis Salles
authors.forename: A
authors.initials: A
authors.lastname: Michel
authors.forename: P L
authors.initials: PL
authors.lastname: Oliveira
authors.forename: N
authors.initials: N
authors.lastname: Cunha-E-Silva
authors.forename: D
authors.initials: D
authors.lastname: Salmon
authors.forename: M C
authors.initials: MC
authors.lastname: Paes
mesh_terms: D000595:Amino Acid Sequence; D053180:Animal Nutrition Sciences; D000818:Animals; D001692:Biological Transport; D002645:Chickens; D003470:Culture Media; D004705:Endocytosis; D005914:Globins / Q000378:metabolism; D006418:Heme / Q000378:metabolism*; D008652:Mesoporphyrins / Q000493:pharmacokinetics; D008954:Models, Biological; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000493:pharmacokinetics; D014349:Trypanosoma cruzi / Q000502:physiology*
chemical_list: D003470:Culture Media; D008652:Mesoporphyrins; D010446:Peptide Fragments; D006418:Heme; C031468:mesoporphyrin IX; D005914:Globins