Integrity of the actin cytoskeleton of host macrophages is essential for Leishmania donovani infection.
Visceral leishmaniasis is a vector-borne disease caused by an obligate intracellular protozoan parasite Leishmania donovani. The molecular mechanism involved in internalization of Leishmania is poorly understood. The entry of Leishmania involves interaction with the plasma membrane of host cells. We have previously demonstrated the requirement of host membrane cholesterol in the binding and internalization of L. donovani into macrophages. In the present work, we explored the role of the host actin cytoskeleton in leishmanial infection. We observed a dose-dependent reduction in the attachment of Leishmania promastigotes to host macrophages upon destabilization of the actin cytoskeleton by cytochalasin D. This is accompanied by a concomitant reduction in the intracellular amastigote load. We utilized a recently developed high resolution microscopy-based method to quantitate cellular F-actin content upon treatment with cytochalasin D. A striking feature of our results is that binding of Leishmania promastigotes and intracellular amastigote load show close correlation with cellular F-actin level. Importantly, the binding of Escherichia coli remained invariant upon actin destabilization of host cells, thereby implying specific involvement of the actin cytoskeleton in Leishmania infection. To the best of our knowledge, these novel results constitute the first comprehensive demonstration on the specific role of the host actin cytoskeleton in Leishmania infection. Our results could be significant in developing future therapeutic strategies to tackle leishmaniasis.
CSIR-Indian Institute of Chemical Biology, Raja S.C. Mullick Road, Kolkata 700 032, India.
Saptarshi
S
Roy
CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
G Aditya
GA
Kumar
CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
Md
M
Jafurulla
CSIR-Indian Institute of Chemical Biology, Raja S.C. Mullick Road, Kolkata 700 032, India. Electronic address: cmandal@iicb.res.in.
Chitra
C
Mandal
CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India. Electronic address: amit@ccmb.res.in.
Amitabha
A
Chattopadhyay
D008841:Actin Cytoskeleton / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology; D007893:Leishmania donovani / Q000472:pathogenicity*; D007896:Leishmaniasis / Q000378:metabolism / Q000469:parasitology*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism / Q000469:parasitology*; D051379:Mice; D008856:Microscopy, Fluorescence; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology
D000199:Actins; D019384:Nucleic Acid Synthesis Inhibitors; D015638:Cytochalasin D
F-actin quantitation; FACS; Leishmania; actin cytoskeleton; cytochalasin D; promastigotes