Biological effects of trans, trans-farnesol in Leishmania amazonensis.

Introduction: Farnesol, derived from farnesyl pyrophosphate in the sterols biosynthetic pathway, is a molecule with three unsaturations and four possible isomers. Candida albicans predominantly secretes the trans, trans-farnesol (t, t-FOH) isomer, known for its role in regulating the virulence of various fungi species and modulating morphological transition processes. Notably, the evolutionary divergence in sterol biosynthesis between fungi, including Candida albicans, and trypanosomatids resulted in the synthesis of sterols with the ergostane skeleton, distinct from cholesterol. This study aims to assess the impact of exogenously added trans, trans-farnesol on the proliferative ability of Leishmania amazonensis and to identify its presence in the lipid secretome of the parasite. Methods: The study involved the addition of exogenous trans, trans-farnesol to evaluate its interference with the proliferation of L. amazonensis promastigotes. Proliferation, cell cycle, DNA fragmentation, and mitochondrial functionality were assessed as indicators of the effects of trans, trans-farnesol. Additionally, lipid secretome analysis was conducted, focusing on the detection of trans, trans-farnesol and related products derived from the precursor, farnesyl pyrophosphate. In silico analysis was employed to identify the sequence for the farnesene synthase gene responsible for producing these isoprenoids in the Leishmania genome. Results: Exogenously added trans, trans-farnesol was found to interfere with the proliferation of L. amazonensis promastigotes, inhibiting the cell cycle without causing DNA fragmentation or loss of mitochondrial functionality. Despite the absence of trans, trans-farnesol in the culture supernatant, other products derived from farnesyl pyrophosphate, specifically α-farnesene and ß-farnesene, were detected starting on the fourth day of culture, continuing to increase until the tenth day. Furthermore, the identification of the farnesene synthase gene in the Leishmania genome through in silico analysis provided insights into the enzymatic basis of isoprenoid production. Discussion: The findings collectively offer the first insights into the mechanism of action of farnesol on L. amazonensis. While trans, trans-farnesol was not detected in the lipid secretome, the presence of α-farnesene and ß-farnesene suggests alternative pathways or modifications in the isoprenoid metabolism of the parasite. The inhibitory effects on proliferation and cell cycle without inducing DNA fragmentation or mitochondrial dysfunction raise questions about the specific targets and pathways affected by exogenous trans, trans-farnesol. The identification of the farnesene synthase gene provides a molecular basis for understanding the synthesis of related isoprenoids in Leishmania. Further exploration of these mechanisms may contribute to the development of novel therapeutic strategies against Leishmania infections.

Análise de evidências de comunicação quorum sensing mediada pelo isoprenóide farnesol em Leishmania amazonensis / Analysis of evidence of quorum sensing communication mediated by isoprenoid farnesol in Leishmania amazonensis

Quorum sensing (QS) é um tipo de comunicação intercelular descrito em microorganismos. Ela é intermediada por moléculas sinalizadoras (QSMs) liberadas constitutivamente pelos espécimes e por meio delas os microorganismos percebem a densidade populacional. [...] Em fungos, trans,trans-farnesol (t,t-FOH) atua como QSM. Esse isoprenóide regula a virulência de Candida albicans modulando os processos de transição morfológica. O t, t- FOH é produzido por uma rota alternativa a partir do farnesilpirofosfato (FPP), um intermediário da via biossíntética de esteróis. Em protozoários, QS já foi descrita no tripanossomatídeo Trypanossoma brucei. Adicionalmente, o processo de metaciclogênese que ocorre em Leishmania possui características de regulação QS, devido sua relação com a densidade populacional. Interessantemente, fungos e tripanossomatídeos possuem maquinaria própria de síntese de esteróis. Essa similaridade e a descrição do t,t-FOH como QSM em fungos sugere que ele pode desempenhar atividade similar em tripanossomatídeos. Em nossa hipótese, t,t-FOH é uma QSM que causa uma redução da capacidade proliferativa de Leishmania amazonensis quando a cultura atinge um quorum. Porém, o parasito mantem-se viável, de modo que a cultura fica estacionária. Inicialmente constatamos que L. amazonensis libera t,t-FOH ou seus derivados no sobrenadante. [...] Essas observações estão de acordo com o perfil de uma possível QSM. Em seguida determinamos as condições de cultivo em que o t,t-FOH possivelmente atua como QSM nas culturas...

Quorum sensing (QS) is a type of intercellular communication described in microorganisms.It is mediated by signaling molecules (QSMs) constitutively released by specimens andthrough them, the microorganisms sense the population density. [...] Infungi, trans,trans-farnesol (t,t-FOH) acts as QSM. This isoprenoid regulates virulence ofCandida albicans interfering the morphological transitions. t,t-FOH is produced by analternative route from farnesylpyrophosphate (FPP), an intermediate of the sterolbiosynthetic pathway. In protozoa, QS has been described in the trypanosomatidTrypanosoma brucei. Additionally, the metacyclogenesis of Leishmania has caracteristics ofQS regulation, due to its relationship with population density. Interestingly, fungi andtrypanosomatids have their own machinery sterol synthesis. This similarity and thedescription of the t, t-FOH as QSM in fungi suggests that it may play similar activity intrypanosomatids. In our hypothesis, t,t-FOH is a QSM which causes a reduction in theproliferative capacity of Leishmania amazonensis when the culture reaches a quorum.However, the parasite keeps viable, so the culture enters in the stationary phase. Initially, wefound that L. amazonensis releases t,t-FOH or its derivatives in the supernatant. Theconcentration of these metabolites enhances with the increase in population density. Theseobservations are consistent with the profile of a possible QSM. Then, we determined thegrowing conditions in which t,t-FOH possibly acts as QSM. [...] We observed that the concentrations that inhibited the proliferation were also apparently toxic. Consideringthat the t,t-FOH is lipophilic, we decided to remove the lipophilic compounds of thesupernatant...

Synthesis and antileishmanial activity of lipophilic aromatic aminoalcohols.

In this work, we report on the preparation and evaluation of the in vitro antileishmanial activity of a series of lipophilic aromatic aminoalcohols. All compounds were assessed for their in vitro antiproliferative activity against promastigotes of three Leishmania species. The most lipophilic aminoalcohols bearing an aliphatic moiety with eight to 12 carbon atoms displayed a good activity against L. amazonensis and L. major, and two of them also showed antiproliferative activity against L. chagasi. The best results were obtained for the N-dodecanoyl ethylenediamine derivative and for N-decyl aminoalcohol (IC50=5.2 and 0.7 microM, respectively).

Biomphalaria spp. (Preston, 1910) snails in the municipality of Juiz de Fora, Zona da Mata Mineira mesoregion, ate of Minas Gerais, Brazil

This study focuses on the geographic distribution of the snail of the genus Biomphalaria and evaluates its infectivity by Schistosoma mansoni in 5264 specimens collected in the municipality of Juiz de Fora, Minas Gerais, Brazil. Of the 31 locations studied, 6 were reservoirs, 11 rudimentary holding ponds, 7 irrigation ditches, 5 lakes, 1 ornamental pond, and 1 waterfall. Intermediate hosts were found only in the rudimentary ponds and ditches, which were 100 percent positive. Using morphological and molecular analysis techniques, B. tenagophila, B. peregrina, and B. straminea were identified. This is the first report of B. stramínea in the municipality, and evaluation of its infective potential revealed susceptibility of 25.4 percent. Although we did not find specimens of Biomphalaria infected by S. mansoni, the data obtained indicate the presence of intermediate hosts, especially in the irrigation ditches in Juiz de Fora, and their proximity to contaminated areas.

Biomphalaria spp. (Preston,1910) snails in the municipality of Juiz de Fora, Zona da Mata Mineira mesoregion, state of Minas Gerais, Brazil.

This study focuses on the geographic distribution of the snail of the genus Biomphalaria and evaluates its infectivity by Schistosoma mansoni in 5264 specimens collected in the municipality of Juiz de Fora, Minas Gerais, Brazil. Of the 31 locations studied, 6 were reservoirs, 11 rudimentary holding ponds, 7 irrigation ditches, 5 lakes, 1 ornamental pond, and 1 waterfall. Intermediate hosts were found only in the rudimentary ponds and ditches, which were 100% positive. Using morphological and molecular analysis techniques, B. tenagophila, B. peregrina, and B. straminea were identified. This is the first report of B. stramínea in the municipality, and evaluation of its infective potential revealed susceptibility of 25.4%. Although we did not find specimens of Biomphalaria infected by S. mansoni, the data obtained indicate the presence of intermediate hosts, especially in the irrigation ditches in Juiz de Fora, and their proximity to contaminated areas.