CK2 Secreted byLeishmania braziliensisMediates Macrophage Association Invasion: A Comparative Study between Virulent and Avirulent Promastigotes

Ana Madeira Brito Zylbersztejn,Ana Karina Castro Lima,Angela Hampshire Lopes,Patrícia Maria Lourenço Dutra,Mário Alberto Cardoso Silva-Neto,Joyce Eliza De Oliveira Souza,Carlos Gustavo Vieira De Morais,Sílvia Amaral Gonçalves Da-Silva

doi:10.1155/2015/167323

Ana Madeira Brito Zylbersztejn, Ana Karina Castro Lima + Show 6 more

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https://doi.org/10.1155/2015/167323

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Abstract

CK2 is a protein kinase distributed in different compartments of Leishmania braziliensis: an externally oriented ecto-CK2, an intracellular CK2, and a secreted CK2. This latter form is constitutively secreted from the parasite (CsCK2), but such secretion may be highly enhanced by the association of specific molecules, including enzyme substrates, which lead to a higher enzymatic activity, called inductively secreted CK2 (IsCK2). Here, we examined the influence of secreted CK2 (sCK2) activity on the infectivity of a virulent L. braziliensis strain. The virulent strain presented 121-fold higher total CK2 activity than those found in an avirulent strain. The use of specific CK2 inhibitors (TBB, DRB, or heparin) inhibited virulent parasite growth, whereas no effect was observed in the avirulent parasites. When these inhibitors were added to the interaction assays between the virulent L. braziliensis strain and macrophages, association index was drastically inhibited. Polyamines enhanced sCK2 activity and increased the association index between parasites and macrophages. Finally, sCK2 and the supernatant of the virulent strain increased the association index between the avirulent strain and macrophages, which was inhibited by TBB. Thus, the kinase enzyme CK2 seems to be important to invasion mechanisms of L. braziliensis.

Highlights

Leishmania braziliensis is an etiological agent of leishmaniasis in the New World [1] that can differentiate from avirulent to virulent promastigotes in the sandfly midgut and from promastigotes to amastigotes in mammalian macrophages
The presence of CK2 activity has been previously described in trypanosomatids [23,24,25,26]
From this point, we will make reference to general secreted CK2 (sCK2) activity, and whenever necessary, the different pools of the enzyme obtained by constitutive secretion will be referred to as Constitutive secreted CK2 activity (CsCK2)

Summary

Introduction

Leishmania braziliensis is an etiological agent of leishmaniasis in the New World [1] that can differentiate from avirulent to virulent promastigotes in the sandfly midgut and from promastigotes to amastigotes in mammalian macrophages. The presence of enzyme activities on the parasite surface can promote the subversion of host cell membrane proteins that regulate access to the intracellular environment. The parasite must ensure their replication and the suppression of host immunity. This process involve complex signal transduction pathways that use the reversible phosphorylation of proteins promoted by protein phosphatases and kinases, which continuously modulate the host-pathogen interaction [3]. In this manner, active enzyme secretion following invasion is likely associated with host cell machinery subversion. Evidence for the existence of such a mechanism is available in several models of host and pathogen interaction [4]

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