, 1994; Brachwitz & Vollgraf, 1995; Wieder et al., 1995; Berkovic et al., 2002; Giantonio et al., 2004). In trypanosomatids, ALPs present potent and selective antiparasitic activity, especially against Leishmania species and Trypanosoma cruzi, by inhibiting cell proliferation and promoting structural damage, as well as morphological alterations (reviewed by Lira et al., 2001; de Castro et al., 2004; Urbina, 2006; Santa-Rita et al., 2005). Previous studies with T. cruzi epimastigotes have shown that ALPs affect the sterol and phospholipid composition,

in this latter case by inhibiting PC biosynthesis via the Greenberg pathway, specifically at the level of PE N-methyltransferase (Lira et al., 2001). In the present work, miltefosine modified the A. deanei lipid composition after 24 h of treatment, when a significant reduction in the amounts of PC and SB431542 datasheet PE were observed. However, as the treatment proceeded, the synthesis of PC increased, whereas the PI production enhanced considerably. In T. brucei, ablation of choline phosphotransferase activity of the Kennedy pathway also induced reduction in PC and PE levels and a protozoan

proliferation arrest, induced by inhibition of nuclear division (Signorelli et al., 2008, 2009). The re-establishment of PC production in longer miltefosine treatments may be due Staurosporine to the fact that cell proliferation is not compromised, probably reflecting low levels of miltefosine in relation to the target enzyme. Furthermore, ultrastructural alterations, such as blebbing and shedding of the plasma membrane, in drug-treated cells is an indication that protozoa can eliminate Benzatropine part of the inhibitor by recycling its membrane components. The recovery of PC production in longer treatments also suggests that both de novo PC biosyntheses are present in A. deanei; thus, the inhibition of the Kennedy pathway by miltefosine treatment may induce

alternative PC production via the Greenberg pathway. However, some authors have proposed that the methylation of PE to PC, which characterizes the Greenberg pathway, is absent in T. brucei (Signorelli et al., 2008; Gibelline et al., 2009; Serricchio & Bütikofer, 2011). It is worth observing that PI synthesis enhances after long treatment with miltefosine, suggesting that phosphoinositide turnover could be intensified, thus promoting an intense signaling response to bypass the harmful effects of the drug in PC production. Previous works have shown that ALPs associate with lipid rafts, thus altering signal transduction pathways that involve phospholipase C and protein kinase C, which are essential regulators of cell proliferation (Nishizuka, 1992; Malaquias & Oliveira, 1999; Wright et al., 2004). The biochemical assays have shown that symbionts and mitochondria, obtained after cell fractioning of A.