A CRISPR-Cas system enhances envelope integrity mediating antibiotic resistance and inflammasome evasion

• Type of Material: Article
• Authors: Timothy Sampson, Emory University; Brooke A. Napier, Emory University; Max R. Schroeder, Emory University; Rogier Louwen, University Medical Centre Rotterdam; Jinshi Zhao, Duke University; Chui-Yoke Chin, Emory University; Hannah K. Ratner, Emory University; Anna C. Liewellyn, Emory University; Crystal L. Jones, Emory University; Hamed Laroui, Georgia State University; Didier Merlin, Georgia State University; Pei Zhou, Duke University; Hubert P. Endtz, University Medical Centre Rotterdam; David Weiss, Emory University
• Language: English
• Date: 2014-07-29
• Publisher: National Academy of Sciences
• Publication Version: Final Published Version
• Copyright Statement: 2014 National Academy of Sciences
• Final Published Version (URL): http://dx.doi.org/10.1073/pnas.1323025111
• Title of Journal or Parent Work: Proceedings of the National Academy of Sciences
• Volume: 111
• Issue: 30
• Start Page: 11163
• End Page: 11168
• Grant/Funding Information: T.R.S. was supported by the National Science Foundation Graduate Research Fellowship Program and the Achievement Rewards for College Scientists Foundation.; J.Z. and P.Z. were supported by NIH R01-AI055588 and GM5-1310.; This work was supported by National Institutes of Health (NIH) Grants U54-AI057157 from the Southeastern Regional Center of Excellence for Emerging Infections and Biodefense, R56-AI87673, and R01-AI110701 (to D.S.W., a Burroughs Wellcome Fund Investigator in the Pathogenesis of Infectious Disease).
• Keywords: AIM2 INFLAMMASOME; TRANSFORMATION; Science & Technology; Multidisciplinary Sciences; innate immune evasion; IDENTIFICATION; RECOGNITION; DEFENSE; ADAPTIVE IMMUNE-SYSTEMS; INNATE IMMUNITY; gene regulation; VIRULENCE; GENES; Science & Technology - Other Topics; FRANCISELLA-TULARENSIS

Abstract

Clustered, regularly interspaced, short palindromic repeats-CRISPR associated (CRISPR-Cas) systems defend bacteria against foreign nucleic acids, such as during bacteriophage infection and transformation, processes which cause envelope stress. It is unclear if these machineries enhance membrane integrity to combat this stress. Here, we show that the Cas9-dependent CRISPR-Cas system of the intracellular bacterial pathogen Francisella novicida is involved in enhancing envelope integrity through the regulation of a bacterial lipoprotein. This action ultimately provides increased resistance to numerous membrane stressors, including antibiotics. We further find that this previously unappreciated function of Cas9 is critical during infection, as it promotes evasion of the host innate immune absent in melanoma 2/apoptosis associated speck-like protein containing a CARD (AIM2/ASC) inflammasome. Interestingly, the attenuation of the cas9 mutant is complemented only in mice lacking both the AIM2/ASC inflammasome and the bacterial lipoprotein sensor Toll-like receptor 2, but not in single knockout mice, demonstrating that Cas9 is essential for evasion of both pathways. These data represent a paradigm shift in our understanding of the function of CRISPR-Cas systems as regulators of bacterial physiology and provide a framework with which to investigate the roles of these systems in myriad bacteria, including pathogens and commensals.