Mycobacterium tuberculosis canonical virulence factors interfere with a late component of the TLR2 response

  1. Amelia E Hinman
  2. Charul Jani
  3. Stephanie C Pringle
  4. Wei R Zhang
  5. Neharika Jain
  6. Amanda J Martinot
  7. Amy K Barczak  Is a corresponding author
  1. Massachusetts General Hospital, United States
  2. Tufts University Cummings School of Veterinary Medicine, United States

Abstract

For many intracellular pathogens, the phagosome is the site of events and interactions that shape infection outcome. Phagosomal membrane damage, in particular, is proposed to benefit invading pathogens. To define the innate immune consequences of this damage, we profiled macrophage transcriptional responses to wild-type Mycobacterium tuberculosis (Mtb) and mutants that fail to damage the phagosomal membrane. We identified a set of genes with enhanced expression in response to the mutants. These genes represented a late component of the TLR2-dependent transcriptional response to Mtb, distinct from an earlier component that included Tnf. Expression of the later component was inherent to TLR2 activation, dependent upon endosomal uptake, and enhanced by phagosome acidification. Canonical Mtb virulence factors that contribute to phagosomal membrane damage blunted phagosome acidification and undermined the endosome-specific response. Profiling cell survival and bacterial growth in macrophages demonstrated that the attenuation of these mutants is partially dependent upon TLR2. Further, TLR2 contributed to the attenuated phenotype of one of these mutants in a murine model of infection. These results demonstrate two distinct components of the TLR2 response and identify a component dependent upon endosomal uptake as a point where pathogenic bacteria interfere with the generation of effective inflammation. This interference promotes TB pathogenesis in both macrophage and murine infection models.

Data availability

RNAseq data is accessible on the NCBI GEO website GSE144330.

The following data sets were generated

Article and author information

Author details

  1. Amelia E Hinman

    The Ragon Institute, Massachusetts General Hospital, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Charul Jani

    The Ragon Institute, Massachusetts General Hospital, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Stephanie C Pringle

    The Ragon Institute, Massachusetts General Hospital, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Wei R Zhang

    The Ragon Institute, Massachusetts General Hospital, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Neharika Jain

    Tufts University Cummings School of Veterinary Medicine, Grafton, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Amanda J Martinot

    Tufts University Cummings School of Veterinary Medicine, Grafton, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Amy K Barczak

    Medicine/Infectious Diseases, Massachusetts General Hospital, Cambridge, United States
    For correspondence
    ABARCZAK@mgh.harvard.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3806-2381

Funding

MGH Transformative Scholar Award

  • Amy K Barczak

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: This study was performed in accordance with guidelines of the Massachusetts General Hospital Institutional Care and Use Committee, under the approved protocols 2014N000297 and 2014N000311.

Reviewing Editor

  1. Christina L Stallings, Washington University School of Medicine, United States

Publication history

  1. Received: September 16, 2021
  2. Preprint posted: October 6, 2021 (view preprint)
  3. Accepted: October 29, 2021
  4. Accepted Manuscript published: November 10, 2021 (version 1)
  5. Version of Record published: November 23, 2021 (version 2)

Copyright

© 2021, Hinman et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 1,120
    Page views
  • 207
    Downloads
  • 4
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Amelia E Hinman
  2. Charul Jani
  3. Stephanie C Pringle
  4. Wei R Zhang
  5. Neharika Jain
  6. Amanda J Martinot
  7. Amy K Barczak
(2021)
Mycobacterium tuberculosis canonical virulence factors interfere with a late component of the TLR2 response
eLife 10:e73984.
https://doi.org/10.7554/eLife.73984
  1. Further reading

Further reading

    1. Chromosomes and Gene Expression
    2. Immunology and Inflammation
    Allison R Wagner, Chi G Weindel ... Kristin L Patrick
    Research Article Updated

    To mount a protective response to infection while preventing hyperinflammation, gene expression in innate immune cells must be tightly regulated. Despite the importance of pre-mRNA splicing in shaping the proteome, its role in balancing immune outcomes remains understudied. Transcriptomic analysis of murine macrophage cell lines identified Serine/Arginine Rich Splicing factor 6 (SRSF6) as a gatekeeper of mitochondrial homeostasis. SRSF6-dependent orchestration of mitochondrial health is directed in large part by alternative splicing of the pro-apoptosis pore-forming protein BAX. Loss of SRSF6 promotes accumulation of BAX-κ, a variant that sensitizes macrophages to undergo cell death and triggers upregulation of interferon stimulated genes through cGAS sensing of cytosolic mitochondrial DNA. Upon pathogen sensing, macrophages regulate SRSF6 expression to control the liberation of immunogenic mtDNA and adjust the threshold for entry into programmed cell death. This work defines BAX alternative splicing by SRSF6 as a critical node not only in mitochondrial homeostasis but also in the macrophage’s response to pathogens.

    1. Computational and Systems Biology
    2. Immunology and Inflammation
    Harry Kane, Nelson M LaMarche ... Lydia Lynch
    Research Article

    Innate T cells, including CD1d-restricted invariant natural killer T (iNKT) cells, are characterized by their rapid activation in response to non-peptide antigens, such as lipids. While the transcriptional profiles of naive, effector and memory adaptive T cells have been well studied, less is known about transcriptional regulation of different iNKT cell activation states. Here, using single cell RNA-sequencing, we performed longitudinal profiling of activated murine iNKT cells, generating a transcriptomic atlas of iNKT cell activation states. We found that transcriptional signatures of activation are highly conserved among heterogeneous iNKT cell populations, including NKT1, NKT2 and NKT17 subsets, and human iNKT cells. Strikingly, we found that regulatory iNKT cells, such as adipose iNKT cells, undergo blunted activation, and display constitutive enrichment of memory-like cMAF+ and KLRG1+ populations. Moreover, we identify a conserved cMAF-associated transcriptional network among NKT10 cells, providing novel insights into the biology of regulatory and antigen experienced iNKT cells.