Reciprocal regulation of reactive oxygen species and phospho-CREB regulates voltage gated calcium channel expression during Mycobacterium tuberculosis infection.

Arti Selvakumar,Cecil Antony,Jhalak Singhal,Yogendra Singh,Brijendra K Tiwari,Krishnamurthy Natarajan,Gobardhan Das

doi:10.1371/journal.pone.0096427

Arti Selvakumar, Cecil Antony + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0096427

Copy DOI

Abstract

Our previous work has demonstrated the roles played by L-type Voltage Gated Calcium Channels (VGCC) in regulating Mycobacterium tuberculosis (M. tb) survival and pathogenesis. Here we decipher mechanisms and pathways engaged by the pathogen to regulate VGCC expression in macrophages. We show that M. tb and its antigen Rv3416 use phospho-CREB (pCREB), Reactive Oxygen Species (ROS), Protein Kinase C (PKC) and Mitogen Activated Protein Kinase (MAPK) to modulate VGCC expression in macrophages. siRNA mediated knockdown of MyD88, IRAK1, IRAK2 or TRAF6 significantly inhibited antigen mediated VGCC expression. Inhibiting Protein Kinase C (PKC) or MEK-ERK1/2 further increased VGCC expression. Interestingly, inhibiting intracellular calcium release upregulated antigen mediated VGCC expression, while inhibiting extracellular calcium influx had no significant effect. siRNA mediated knockdown of transcription factors c-Jun, SOX5 and CREB significantly inhibited Rv3416 mediated VGCC expression. A dynamic reciprocal cross-regulation between ROS and pCREB was observed that in turn governed VGCC expression with ROS playing a limiting role in the process. Further dissection of the mechanisms such as the interplay between ROS and pCREB would improve our understanding of the regulation of VGCC expression during M. tb infection.

Highlights

Tuberculosis caused by Mycobacterium tuberculosis (M. tb) results in high mortality and morbidity of individuals in the world
To begin with we examined the ability of Rv3416 to modulate Voltage Gated Calcium Channels (VGCC) expression on macrophages
Since VGCC played a major role in immune evasion to M. tb, we investigated the role of Rv3416 in mediating VGCC expression in macrophages

Summary

Introduction

Tuberculosis caused by Mycobacterium tuberculosis (M. tb) results in high mortality and morbidity of individuals in the world. Delineating the intricate network during host-pathogen interactions at the molecular and cellular levels is key to the development of vaccines and therapeutics. One such molecule that plays a central role in the above interactions is calcium. The first phase is the depletion of intracellular stores from the endoplasmic reticulum followed by the capacitative phase that is mediated by the activation of store operated calcium channels, leading to a sustained increase in intracellular calcium concentrations [5]. Extensively studied in physiological states and disorders [7,8], the role of VGCC in infections is beginning to be appreciated [9,10,11]

Methods

Results

Conclusion