Reversible paralysis of Schistosoma mansoni by forchlorfenuron, a phenylurea cytokinin that affects septins.
Septins are guanosine-5'-triphosphate-binding proteins involved in wide-ranging cellular processes including cytokinesis, vesicle trafficking, membrane remodelling and scaffolds, and with diverse binding partners. Precise roles for these structural proteins in most processes often remain elusive. Identification of small molecules that inhibit septins could aid in elucidating the functions of septins and has become increasingly important, including the description of roles for septins in pathogenic phenomena such as tumorigenesis. The plant growth regulator forchlorfenuron, a synthetic cytokinin known to inhibit septin dynamics, likely represents an informative probe for septin function. This report deals with septins of the human blood fluke Schistosoma mansoni and their interactions with forchlorfenuron. Recombinant forms of three schistosome septins, SmSEPT5, SmSEPT7.2 and SmSEPT10, interacted with forchlorfenuron, leading to rapid polymerization of filaments. Culturing developmental stages (miracidia, cercariae, adult males) of schistosomes in FCF at 50-500 μM rapidly led to paralysis, which was reversible upon removal of the cytokinin. The reversible paralysis was concentration-, time- and developmental stage-dependent. Effects of forchlorfenuron on the cultured schistosomes were monitored by video and/or by an xCELLigence-based assay of motility, which quantified the effect of forchlorfenuron on fluke motility. The findings implicated a mechanism targeting a molecular system controlling movement in these developmental stages: a direct effect on muscle contraction due to septin stabilization might be responsible for the reversible paralysis, since enrichment of septins has been described within the muscles of schistosomes. This study revealed the reversible effect of forchlorfenuron on both schistosome motility and its striking impact in hastening polymerization of septins. These novel findings suggested routes to elucidate roles for septins in this pathogen, and exploitation of derivatives of forchlorfenuron for anti-schistosomal drugs.
Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil; Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20037, USA.
Ana E
AE
Zeraik
Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23507, USA.
Vitold E
VE
Galkin
Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20037, USA; Departamento de Genética, Facultad de Medicina, Universidad de la República (UDELAR), Montevideo, Uruguay.
Gabriel
G
Rinaldi
Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.
Richard C
RC
Garratt
Australian Institute of Tropical Health and Medicine, Queensland Tropical Health Alliance, James Cook University, McGregor Rd, Smithfield, Cairns, Queensland 4878, Australia.
Michael J
MJ
Smout
Australian Institute of Tropical Health and Medicine, Queensland Tropical Health Alliance, James Cook University, McGregor Rd, Smithfield, Cairns, Queensland 4878, Australia.
Alex
A
Loukas
Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20037, USA.
Victoria H
VH
Mann
Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil.
Ana P U
AP
Araujo
Departamento de Física e Informática, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil. Electronic address: rdemarco@ifsc.usp.br.
Ricardo
R
DeMarco
Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20037, USA. Electronic address: pbrindley@gwu.edu.
Paul J
PJ
Brindley
D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology*; D003583:Cytokinins / Q000494:pharmacology; D010243:Paralysis / Q000139:chemically induced*; D010671:Phenylurea Compounds / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D012550:Schistosoma mansoni / Q000187:drug effects*; D058112:Septins / Q000037:antagonists & inhibitors*
D000871:Anthelmintics; D003583:Cytokinins; D010671:Phenylurea Compounds; D011725:Pyridines; D058112:Septins; C116093:N-(2-chloro-4-pyridyl)-N'-phenylurea
Cercariae; Cytokinin; Forchlorfenuron; Miracidium; Phenylurea; Schistosome; Septin; xCELLigence