title: The HIV Nef protein modulates cellular and exosomal miRNA profiles in human monocytic cells.
abstract: BACKGROUND
  The HIV Nef protein is a multifunctional virulence factor that perturbs intracellular membranes and signalling and is secreted into exosomes. While Nef-containing exosomes have a distinct proteomic profile, no comprehensive analysis of their miRNA cargo has been carried out. Since Nef functions as a viral suppressor of RNA interference and disturbs the distribution of RNA-induced silencing complex proteins between cells and exosomes, we hypothesized that it might also affect the export of miRNAs into exosomes.
  
  
  METHODS
  Exosomes were purified from human monocytic U937 cells that stably expressed HIV-1 Nef. The RNA from cells and exosomes was profiled for 667 miRNAs using a Taqman Low Density Array. Selected miRNAs and their mRNA targets were validated by quantitative RT-PCR. Bioinformatics analyses were used to identify targets and predict pathways.
  
  
  RESULTS
  Nef expression affected a significant fraction of miRNAs in U937 cells. Our analysis showed 47 miRNAs to be selectively secreted into Nef exosomes and 2 miRNAs to be selectively retained in Nef-expressing cells. The exosomal miRNAs were predicted to target several cellular genes in inflammatory cytokine and other pathways important for HIV pathogenesis, and an overwhelming majority had targets within the HIV genome.
  
  
  CONCLUSIONS
  This is the first study to report miRnome analysis of HIV Nef expressing monocytes and exosomes. Our results demonstrate that Nef causes large-scale dysregulation of cellular miRNAs, including their secretion through exosomes. We suggest this to be a novel viral strategy to affect pathogenesis and to limit the effects of RNA interference on viral replication and persistence.
authors.affiliation: Virology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India;
authors.forename: Madeeha
authors.initials: M
authors.lastname: Aqil
authors.affiliation: Virology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India;
authors.forename: Afsar Raza
authors.initials: AR
authors.lastname: Naqvi
authors.affiliation: Machine Intelligence Unit, Indian Statistical Institute, Kolkata, India.
authors.forename: Saurav
authors.initials: S
authors.lastname: Mallik
authors.affiliation: Machine Intelligence Unit, Indian Statistical Institute, Kolkata, India.
authors.forename: Sanghamitra
authors.initials: S
authors.lastname: Bandyopadhyay
authors.affiliation: Department of Computer Science and Engineering, Jadavpur University, Kolkata, India.
authors.forename: Ujjwal
authors.initials: U
authors.lastname: Maulik
authors.affiliation: Virology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India;
authors.forename: Shahid
authors.initials: S
authors.lastname: Jameel
keywords: HIV; Nef; exosomes; inflammatory cytokine; miRNA