Effects of miltefosine on the proliferation, ultrastructure, and phospholipid composition of Angomonas deanei, a trypanosomatid protozoan that harbors a symbiotic bacterium.
Some trypanosomatids, such as Angomonas deanei formerly named as Crithidia deanei, present an obligatory intracellular bacterium, which maintains a mutualistic relationship with the host. Phosphatidylcholine (PC) is the major phospholipid in eukaryotes and an essential component of cell membranes playing structural, biochemical, and physiological roles. However, in prokaryotes, PC is present only in those species closely associated with eukaryotes, either in symbiotic or pathogenic interactions. In trypanosomatids, the endosymbiont envelope is composed by a reduced cell wall and by two membrane units that lack sterols and present cardiolipin (CL) and PC as the major phospholipids. In this study, we tested the effects of miltefosine in A. deanei proliferation, as well as, on the ultrastrucuture and phospholipid composition considering that this drug inhibits the CTP-phosphocholine cytidyltransferase (CCT), a key enzyme in the PC biosynthesis. Besides the low effect of miltefosine in cellular proliferation, treated protozoa presented ultrastructural alterations such as plasma membrane shedding and blebbing, mitochondrial swelling, and convolutions of the endosymbiont envelope. The use of (32) Pi as a tracer revealed that the production of PC, CL, and phosphatidylethanolamine decreased while phosphatidylinositol production remained stable. Mitochondrion and symbiont fractions obtained from protozoa treated with miltefosine also presented a decrease in phospholipid production, reinforcing the idea that an intensive metabolic exchange occurs between the host trypanosomatid and structures of symbiotic origin.
Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Paulo R G
PR
de Freitas-Junior
Carolina M C
CM
Catta-Preta
Iamara da Silva
Ida S
Andrade
Danielle P
DP
Cavalcanti
Wanderley
W
de Souza
Marcelo
M
Einicker-Lamas
Maria Cristina M
MC
Motta
D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D019916:Choline-Phosphate Cytidylyltransferase / Q000378:metabolism; D003421:Crithidia / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects / Q000648:ultrastructure; D010713:Phosphatidylcholines / Q000096:biosynthesis; D010759:Phosphorus Isotopes / Q000378:metabolism; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013559:Symbiosis
D010713:Phosphatidylcholines; D010759:Phosphorus Isotopes; D010767:Phosphorylcholine; C039128:miltefosine; D019916:Choline-Phosphate Cytidylyltransferase