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Proteomic and Genomic Analysis of Leishmania donovani Parasites for their Survival in Mammalian Host and Designing Therapeutic Strategies to Combat the Disease

IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata


Field	Value

Title	Proteomic and Genomic Analysis of Leishmania donovani Parasites for their Survival in Mammalian Host and Designing Therapeutic Strategies to Combat the Disease

Creator	Sinha, Roma

Subject	Infectious Diseases and Immunology

Description	Visceral leishmaniasis (VL) is an immunosuppressive disease which is fatal if left untreated. Non-availability of vaccine, invasive methods of diagnosis and limitations of currently available therapies further complicate the problem. Designing effective therapies need detailed understanding of both parasite and host factors responsible for infection. Leishmania secrete virulence factors which modulate host immunity for their survival. We observed loss of virulence in Leishmania donovani promastigotes as a result of continuous axenic cultivation, resulting in differential modulation of macrophage microbicidal activity in vitro and higher immunostimulation in animals. Comparative proteomic screening of L. donovani AG83 promastigotes of early and late passages identified decrease in expression of some important virulence factors viz., gp63, HSP70, LACK, EF1-, dihydrolipoamide acetyltransferase, etc. providing the basis for loss of virulence. Post-transcriptional and post-translational modifications determine the ultimate protein repertoire in Leishmania. We generated RNA-Seq data to compare the transcript abundance in early (2nd), intermediate (11th), and late (25th) passages, and found altered metabolism, signaling, DNA repair and RNA editing processes which may account for the gross changes in protein expression when grown for longer periods in culture. We could cite similarity of parasite multiplication and dissemination with cancer cell division and metastasis in terms of gene expression pattern. Thus we propose that common pathway or target based clinical interventions can be designed for VL and cancer. Based on our understanding of the parasite and host factors of VL we did mechanistic study on previously developed cationic drug free and pentavalent antimonial (SbV) entrapped phosphatidylcholine (PC) - stearylamine (SA) liposomes and compared their efficacy with PC-dioctadecyldimethylammonium bromide (DDAB) vesicles. We observed increased retention and slow release of liposomal drug responsible for resistance reversal and phosphatidylserine-mediated direct leishmanicidal activity in vitro and host-protective immomodulation for effective therapy in vivo, with PC-DDAB being a better antileishmanial requiring a 4-times less dose for equivalent activity. To further improve this formulation we entrapped TGF-β signaling inhibitor SB-505124 (SB), earlier used in cancer therapy, in PC-SA and encapsulated globally used form of SbV, meglumine antimoniate (MA) into it (PC-SA-SB-MA). After successful in vitro screening we observed near sterile cure in a mice model of infection with a dose of 10 mg/kg b.w. w.r.t. PC of PC-SA entrapping 50mg/kg b.w of SB and encapsulating 6 mg/kg b.w. of MA, whereas 20 mg/kg b.w of only PC-SA-MA was inferior in clearing parasites from liver, spleen and bone marrow of infected mice. Clearance of parasites was accompanied with higher IFN-/IL-10 ratio for successful cure. Thus our liposomal formulations can act as dual modulators of parasite and host. To conclude, similarities between VL and cancer can be exploited in identifying drug and vaccine targets and designing common clinical interventions for these diseases.

Date	2016

Type	Thesis NonPeerReviewed

Format	application/pdf

Identifier	http://www.eprints.iicb.res.in/2611/1/Roma_Sinha_thesis_.pdf Sinha, Roma (2016) Proteomic and Genomic Analysis of Leishmania donovani Parasites for their Survival in Mammalian Host and Designing Therapeutic Strategies to Combat the Disease. PhD thesis, C U.

Relation	http://www.eprints.iicb.res.in/2611/