title: Spinigerin induces apoptotic like cell death in a caspase independent manner in Leishmania donovani.
abstract: Antimicrobial peptides (AMPs) are multifunctional components of the innate immune system. Chemotherapeutic agents used for treatment of visceral leishmaniasis (VL) are now threatened due to the emergence of acquired drug resistance and toxicity. AMPs are attractive alternative to conventional pharmaceuticals. In this study, first time we explored the antileishmanial activity of spinigerin originally derived from Pseudacanthotermes spiniger. Leishmania donovani promastigotes present apoptosis-like cell death upon exposure to spinigerin (IC50, 150 μM). The infection rate was reduced by 20% upon exposure to 150 μM spinigerin but no cytotoxicity on host macrophages was observed. Elevation of intracellular ROS level and down-regulation of two ROS detoxifying enzymes, ascorbate peroxidase (APx) and trypanothione reductase (TR) suggested essential role of ROS machinery during spinigerin mediated cell death. About 97% cell population was found to be Annexin-V positive; 44% cells being highly Annexin-V positive. Moreover, we observed morphological changes like cell rounding, nuclear condensation, oligonucleosomal DNA degradation and TUNEL positive cells without loss of membrane integrity upon spinigerin exposure, suggests apoptosis-like death. Interestingly, collapse in mitochondrial membrane potential and increased level of intracellular ROS and calcium were not associated with caspase like activity. Computational analysis suggests spiningerin interacts with trypanothione reductase and thus probably interferes its function to detoxify the toxic ROS level. Therefore, spinigerin induces apoptosis-like cell death in L. donovani in a caspase-independent manner. The study elucidates the antileishmanial property of spinigerin that may be considered for future chemotherapeutic option alone or adjunct with other drug regimens for improved treatment of visceral leishmaniasis.
authors.affiliation: Division of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences (ICMR), Agamkuan, Patna 800007, India.
authors.forename: A H
authors.initials: AH
authors.lastname: Sardar
authors.forename: S
authors.initials: S
authors.lastname: Das
authors.forename: S
authors.initials: S
authors.lastname: Agnihorti
authors.forename: M
authors.initials: M
authors.lastname: Kumar
authors.forename: A K
authors.initials: AK
authors.lastname: Ghosh
authors.forename: K
authors.initials: K
authors.lastname: Abhishek
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: B
authors.initials: B
authors.lastname: Purkait
authors.forename: M Y
authors.initials: MY
authors.lastname: Ansari
authors.forename: P
authors.initials: P
authors.lastname: Das
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides; D000981:Antiprotozoal Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis; D060387:Ascorbate Peroxidases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D020128:Inhibitory Concentration 50; D020049:Isoptera / Q000737:chemistry; D007893:Leishmania donovani / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D007898:Leishmaniasis, Visceral / Q000188:drug therapy*; D015227:Lipid Peroxidation / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000469:parasitology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D010455:Peptides / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D023181:Antimicrobial Cationic Peptides; D000981:Antiprotozoal Agents; D010455:Peptides; D017382:Reactive Oxygen Species; C428303:spinigerin; D060387:Ascorbate Peroxidases; D009247:NADH, NADPH Oxidoreductases; C049608:trypanothione reductase; D020169:Caspases; D002118:Calcium
keywords: AMP; Annexin-V; Apoptosis; Spinigerin; TUNEL