Functional genomic analysis of Candida glabrata-macrophage interaction: role of chromatin remodeling in virulence

PLoS Pathog. 2012;8(8):e1002863. doi: 10.1371/journal.ppat.1002863. Epub 2012 Aug 16.

Abstract

Fungal septicemia is an increasingly common complication of immunocompromised patients worldwide. Candida species are the leading cause of invasive mycoses with Candida glabrata being the second most frequently isolated Candida species from Intensive Care Unit patients. Despite its clinical importance, very little is known about the mechanisms that C. glabrata employs to survive the antimicrobial and immune response of the mammalian host. Here, to decipher the interaction of C. glabrata with the host immune cells, we have screened a library of 18,350 C. glabrata Tn7 insertion mutants for reduced survival in human THP-1 macrophages via signature-tagged mutagenesis approach. A total of 56 genes, belonging to diverse biological processes including chromatin organization and golgi vesicle transport, were identified which are required for survival and/or replication of C. glabrata in macrophages. We report for the first time that C. glabrata wild-type cells respond to the intracellular milieu of macrophage by modifying their chromatin structure and chromatin resistance to micrococcal nuclease digestion, altered epigenetic signature, decreased protein acetylation and increased cellular lysine deacetylase activity are the hall-marks of macrophage-internalized C. glabrata cells. Consistent with this, mutants defective in chromatin organization (Cgrsc3-aΔ, Cgrsc3-bΔ, Cgrsc3-aΔbΔ, Cgrtt109Δ) and DNA damage repair (Cgrtt107Δ, Cgsgs1Δ) showed attenuated virulence in the murine model of disseminated candidiasis. Further, genome-wide transcriptional profiling analysis on THP-1 macrophage-internalized yeasts revealed deregulation of energy metabolism in Cgrsc3-aΔ and Cgrtt109Δ mutants. Collectively, our findings establish chromatin remodeling as a central regulator of survival strategies which facilitates a reprogramming of cellular energy metabolism in macrophage-internalized C. glabrata cells and provide protection against DNA damage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Candida glabrata / genetics
  • Candida glabrata / immunology
  • Candida glabrata / metabolism
  • Candida glabrata / pathogenicity*
  • Candidiasis / genetics
  • Candidiasis / immunology
  • Candidiasis / metabolism*
  • Cell Line
  • Chromatin Assembly and Disassembly*
  • Epigenesis, Genetic*
  • Gene Expression Regulation, Fungal*
  • Genes, Fungal*
  • Genome-Wide Association Study
  • Humans
  • INDEL Mutation
  • Macrophages / metabolism
  • Macrophages / microbiology*
  • Mice

Grants and funding

This work was supported financially, in part, by Innovative Young Biotechnologist Award BT/BI/12/040/2005 from Department of Biotechnology, Government of India (www.dbtindia.nic.in) and by core funds of Centre for DNA Fingerprinting and Diagnostics (www.cdfd.org.in), Hyderabad. M.N. Rai is a recipient of Senior Research Fellowship from Council of Scientific and Industrial Research, India. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.