Anaplasma phagocytophilum infection modulates expression of megakaryocyte cell cycle genes through phosphatidylinositol-3-kinase signaling

Supreet Khanal,Girish Neelakanta,Jason A Carlyon,Hameeda Sultana,John D Catravas,Ulrike Gertrud Munderloh

doi:10.1371/journal.pone.0182898

Supreet Khanal, Girish Neelakanta + Show 4 more

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https://doi.org/10.1371/journal.pone.0182898

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Abstract

Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis infects neutrophils and other cells from hematopoietic origin. Using human megakaryocytic cell line, MEG-01, we show that expression of cell cycle genes in these cells are altered upon A. phagocytophilum infection. Expression of several cell cycle genes in MEG-01 cells was significantly up regulated at early and then down regulated at later stages of A. phagocytophilum infection. Lactate dehydrogenase (LDH) assays revealed reduced cellular cytotoxicity in MEG-01 cells upon A. phagocytophilum infection. The levels of both PI3KCA (p110 alpha, catalytic subunit) and PI3KR1 (p85, regulatory subunit) of Class I PI3 kinases and phosphorylated protein kinase B (Akt/PKB) and inhibitory kappa B (IκB) were elevated at both early and late stages of A. phagocytophilum infection. Inhibition of PI3 kinases with LY294002 treatment resulted in significant reduction in the expression of tested cell cycle genes, A. phagocytophilum burden and phosphorylated Akt levels in these MEG-01 cells. Collectively, these results suggest a role for PI3K-Akt-NF-κB signaling pathway in the modulation of megakaryocyte cell cycle genes upon A. phagocytophilum infection.

Highlights

In the United States, human granulocytic anaplasmosis (HGA) is one of the most common tick-borne diseases [1, 2]
Due to the significant difference in the bacterial burden observed between two time points, the day 1 p.i. time point was considered as an early stage and day 7 p.i. as a late stage of A. phagocytophilum infection of Megakaryoblast cell line (MEG-01) cells
Assays performed with supernatants collected from A. phagocytophiluminfected MEG-01 cells treated with LY294002 at late time point showed increased (P

Summary

Introduction

In the United States, human granulocytic anaplasmosis (HGA) is one of the most common tick-borne diseases [1, 2]. Previous studies have shown that up to 30% of human population in endemic areas may have been exposed to A. phagocytophilum infections [3, 4]. At least 15, 952 HGA cases have been reported since 1995 with a 12-fold increased rate in 2001–2011 [5]. Infections in many cases are asymptomatic [2, 3, 5, 6].

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