Involvement of protein kinase C isoenzymes in Trypanosoma cruzi metacyclogenesis induced by oleic acid

Previously, we showed that oleic acid (OA) induces Trypanosoma cruzi metacyclogenesis through a signaling pathway involving de novo diacylglycerol biosynthesis and simultaneous protein kinase C (PKC) activation. Herein, we demonstrated that OA also triggers a transient Ca²⁺ signal in epimastigotes, necessary for parasite differentiation, that could account for PKC activation. In addition, we found that this free fatty acid (FFA) directly stimulated in vitro the activity of T. cruzi PKC in a dose–response way. We determined the presence of classical and novel PKC isoenzymes that were differentially expressed in the infective amastigotes (α and δ) and tripomastigotes (α, β, and γ) and in the non-infective epimastigotes (α, β, γ, and δ). We also demonstrated that OA induced in epimastigotes the translocation of PKC α, β, γ, and δ to the membrane, indicating a selective effect of this FFA. To establish a correlation between T. cruzi metacyclogenesis induced by OA and the activation of a particular PKC isoenzyme, the specific PKC inhibitors Ro 32-0432 and Rottlerin (9–30 nM and 5–35 μM, respectively) were employed. These compounds, even at the lowest concentrations assayed, abrogated both epimastigote differentiation and membrane translocation of PKC β, γ, and δ. These findings strongly support a key role for classical and novel PKC isoenzymes in the signaling pathways involved in T. cruzi metacyclogenesis induced by OA.