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Role of durg sensitive and resistant form of Leishmania donovani in controlling exosomal cargo release by host cell

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


Field	Value

Title	Role of durg sensitive and resistant form of Leishmania donovani in controlling exosomal cargo release by host cell

Creator	Ganguly, Satarupa

Subject	Molecular & Human Genetics

Description	Post-transcriptional regulation of different mRNAs is one of the ways to control particular gene expression and this type of regulation is mediated by a group of small RNAs known as MicroRNAs (miRNA). These miRNAs are 20-22 nucleotide long and they can bind to the 3’ UTR of target mRNA to initiate the translational repression or mRNA degradation. They are found to be involve in the regulation of almost all biological phenomenon & their alteration of expression is associated with various disease condition. miRNAs not only regulate the expression of mRNAs of host cell but also can regulate expression of target mRNAs in neighboring cell when it gets transferred by exosome. Exosomes are small membrane bound vesicle of 30-100nm size and they are originated from Multivesicular Bodies (MVB). But exosomes not only known to carry miRNAs but also carries different proteins & lipids. However, different pathological conditions can lead to alteration of exosomal cargoes and their effect on neighboring cells. EVs play diverse role during a disease condition. It either provides host protective molecules to neighboring cells or provide disease spreading molecules or some virulence factors. Pathogens can regulate miRNA machinery as well as EV secretion & cargo contents in order to survive within host cell. Leishmania donovani (Ld) is an intracellular parasite that resides in macrophage and regulate its innate immune system for their own survival. Ld affects endosome maturation thereby hampered miRNP recycling which resulted in altered cytokine production. Also, it regulates cholesterol metabolism by targeting miR-122 in liver cells and increases miRNA stability by targeting mitochondrial dynamics in order to regulate the inflammatory response of macrophages. Emergence of parasite resistance against anti-leishmanial drugs are adding new hurdles in VL in nowadays. This made us interested in studying the effect of drug sensitive & resistant parasite in regulating miRNA mediated immune response in host macrophage and also in neighboring cells by regulating host cell exosomal machinery. We have shown that both the strains reciprocally regulate PP2A and HuR expression. PP2A dephosphorylates Ago2 to increase its association with miRNAs. This increased miRNAAgo2 association maintains the anti-inflammatory environment that favors parasite survival within host cells. Several RNA binding proteins are known to regulate miRNA mediated gene regulation. Such RNA binding protein is HuR which is a miRNA derepressor protein responsible for miRNA-Ago2 uncoupling to favor the proinflammatory environment that promote parasite killing. In this study, we find that HuR overexpression decreases parasite load for the LdS strain in in vivo. But cannot reduce parasite load for LdR strain. However, simultaneous inhibition of PP2A by Okadaic acid treatment shows clearance of LdR parasites in in vivo mice model. Upregulation of PP2A hampered miRNP recycling which might regulate the exosomal release of miRNAs. Hence, we check the exosomal contents of macrophages after infection with both strains and find increased level of miR-146a in exosome but interestingly miR- 155 is not detected. The neighboring macrophages showed M2 phenotype after exosome treatment for LdS strain derived exosomes and it reduces LdS internalization. But macrophages treated with LdR infected cell derive exosomes does not showed M2 phenotype but suppress both pro and anti-inflammatory cytokine production. However, exosome treatment reduces LdR parasites internalization in naïve macrophages more vigorously than their sensitive counterpart. We also found that exosomal transfer of miR- 146a not only regulate immune response of naïve macrophages but also show effect on hepatic cells by downregulating miR-122 which involves in inflammatory response. Our findings show a novel protective role of exosome in preventing Ld infection caused by both drug sensitive & resistant strains, by means of increased exosomal export of miR-146a from infected cell to uninfected macrophages and hepatocyte. Also, in this study we find a new therapeutic role of HuR & okadaic acid in preventing the infection caused by the aggressive drug resistant strain of Ld.

Date	2022

Type	Thesis NonPeerReviewed

Format	application/pdf

Identifier	http://www.eprints.iicb.res.in/2853/1/1646206560867_Thesis_for_Evaluation_Satarupa_Ganguly.pdf Ganguly, Satarupa (2022) Role of durg sensitive and resistant form of Leishmania donovani in controlling exosomal cargo release by host cell. PhD thesis, UNIVERSITY OF CALCUTTA.

Relation	http://www.eprints.iicb.res.in/2853/