Extracellular lipid droplets promote hemozoin crystallization in the gut of the blood fluke Schistosoma mansoni.
Hemozoin (Hz) is a heme crystal produced upon hemoglobin digestion as the main mechanism of heme disposal in several hematophagous organisms. Here, we show that, in the helminth Schistosoma mansoni, Hz formation occurs in extracellular lipid droplets (LDs). Transmission electron microscopy of adult worms revealed the presence of numerous electron-lucent round structures similar to LDs in gut lumen, where multicrystalline Hz assemblies were found associated to their surfaces. Female regurgitates promoted Hz formation in vitro in reactions partially inhibited by boiling. Fractionation of regurgitates showed that Hz crystallization activity was essentially concentrated on lower density fractions, which have small amounts of pre-formed Hz crystals, suggesting that hydrophilic-hydrophobic interfaces, and not Hz itself, play a key catalytic role in Hz formation in S. mansoni. Thus, these data demonstrate that LDs present in the gut lumen of S. mansoni support Hz formation possibly by allowing association of heme to the lipid-water interface of these structures.
Corrêa Soares
Juliana B R
JB
Instituto de Bioquímica Médica, Programa de Biologia Molecular e Biotecnologia, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, Brazil.
Maya-Monteiro
Clarissa M
CM
Bittencourt-Cunha
Paula R B
PR
Atella
Geórgia C
GC
Lara
Flávio A
FA
d'Avila
Joana C P
JC
Menezes
Diego
D
Vannier-Santos
Marcos A
MA
Oliveira
Pedro L
PL
Egan
Timothy J
TJ
Oliveira
Marcus F
MF
D000818:Animals; D003460:Crystallization; D005260:Female; D006420:Hemeproteins / Q000737:chemistry* / Q000187:drug effects*; D057927:Hydrophobic and Hydrophilic Interactions; D007422:Intestines / Q000737:chemistry; D008055:Lipids / Q000494:pharmacology*; D012550:Schistosoma mansoni / Q000033:anatomy & histology
D006420:Hemeproteins; D008055:Lipids; C020753:hemozoin