Infectious disease is a global threat to human health. The World Health Organization notes a pressing need to develop novel antimicrobial strategies that limit the impact of these life-threatening pathogens. These pathogens include the major causative agents of nosocomial infections, e.g., Staphylococcus aureus, and a major respiratory pathogen responsible for community-acquired pneumonia and morbidity world-wide, Streptococcus pneumoniae. Each is becoming increasingly multidrug-resistant severely complicating treatment options. In this proposal, we seek to integrate our fundamental studies of bacterial transition metal (manganese, copper and zinc) homeostasis, sulfur metabolism and sulfide homeostasis to accelerate the pace of discovery of novel antibacterial strategies. We have long-standing interests in the transcriptional repressors and more recently, metal trafficking proteins, that allow a bacterium to adapt to host-mediated remodeling of transition metal availability. We've discovered and structurally characterized new players in this process in M. tuberculosis, S. aureus and S. pneumoniae and have framed our quantitative investigations of these systems as allosteric inorganic switches that orchestrate metal homeostasis and resistance to toxicity in cells. These studies led directly to the discovery and ongoing elucidatio of what we anticipate represents a novel, highly specific regulatory response to reactive sulfur species (RSS) and potentially, reactive nitrogen oxide species (nitroxyl; HNO) in S. aureus. We hypothesize that this response impacts the ability of S. aureus and other pathogens to regulate colonization and nitric oxide (NO)-mediated dispersal of biofilms (biofilm dynamics) and resistance to antibiotic-induced oxidative stress. Future studies will be carried out in three general areas: 1) biological characterization and structural/dynamics studies, using state-of-the-art methyl-specific NMR relaxation experiments, of new allosteric systems involved in metalloregulation of transcription and regulation of RSS and RNOS; 2) obtaining new molecular-level insights into copper resistance and manganese homeostasis in S. pneumoniae, and mechanisms of adaptation to extreme zinc limitation induced by host-mediated nutritional immunity in Acinetobacter baumannii, and 3) holistically probe the cellular response to sulfide and RNOS stress using transcriptomic, mass spectrometry-based profiling of proteome cysteine thiol oxidative modifications, and targeted metabolite profiling approaches, with the goal to identity new players and mechanisms in this process. Our multidisciplinary approach, which seamlessly spans biophysical chemistry to microbial physiology, enhances the probability of transforming our understanding of fundamental features of transition metal homeostasis linked to virulence and a completely unexplored cellular response to RSS/RNOS in important human pathogens.

Public Health Relevance

Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and other bacterial pathogens are significant threats to global human health. In this proposal, we outline a multi-pronged approach to significantly enhance our understanding of two regulatory processes linked to the survival of these organisms in the host. How cells adapt to host-mediated changes in the availability of essential transition metal nutrients and hydrogen sulfide misregulation is the focus of these studies. New targets for the development of novel antimicrobial therapies may well result from this project.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Unknown (R35)
Project #
1R35GM118157-01
Application #
9071683
Study Section
Special Emphasis Panel (ZGM1-TRN-Y (MR))
Program Officer
Anderson, Vernon
Project Start
2016-06-01
Project End
2021-05-31
Budget Start
2016-06-01
Budget End
2017-05-31
Support Year
1
Fiscal Year
2016
Total Cost
$579,235
Indirect Cost
$197,880
Name
Indiana University Bloomington
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
006046700
City
Bloomington
State
IN
Country
United States
Zip Code
47401
Shen, Jiangchuan; Walsh, Brenna J C; Flores-Mireles, Ana Lidia et al. (2018) Hydrogen Sulfide Sensing through Reactive Sulfur Species (RSS) and Nitroxyl (HNO) in Enterococcus faecalis. ACS Chem Biol 13:1610-1620
Glauninger, Hendrik; Zhang, Yifan; Higgins, Khadine A et al. (2018) Metal-dependent allosteric activation and inhibition on the same molecular scaffold: theĀ copper sensor CopY from Streptococcus pneumoniae. Chem Sci 9:105-118
Capdevila, Daiana A; Huerta, Fidel; Edmonds, Katherine A et al. (2018) Tuning site-specific dynamics to drive allosteric activation in a pneumococcal zinc uptake regulator. Elife 7:
Peng, Hui; Zhang, Yixiang; Palmer, Lauren D et al. (2017) Hydrogen Sulfide and Reactive Sulfur Species Impact Proteome S-Sulfhydration and Global Virulence Regulation in Staphylococcus aureus. ACS Infect Dis 3:744-755
Capdevila, Daiana A; Braymer, Joseph J; Edmonds, Katherine A et al. (2017) Entropy redistribution controls allostery in a metalloregulatory protein. Proc Natl Acad Sci U S A 114:4424-4429
Martin, Julia E; Lisher, John P; Winkler, Malcolm E et al. (2017) Perturbation of manganese metabolism disrupts cell division in Streptococcus pneumoniae. Mol Microbiol 104:334-348
Capdevila, Daiana A; Edmonds, Katherine A; Giedroc, David P (2017) Metallochaperones and metalloregulation in bacteria. Essays Biochem 61:177-200
Martin, Julia E; Edmonds, Katherine A; Bruce, Kevin E et al. (2017) The zinc efflux activator SczA protects Streptococcus pneumoniae serotype 2 D39 from intracellular zinc toxicity. Mol Microbiol 104:636-651
Shimizu, Takayuki; Shen, Jiangchuan; Fang, Mingxu et al. (2017) Sulfide-responsive transcriptional repressor SqrR functions as a master regulator of sulfide-dependent photosynthesis. Proc Natl Acad Sci U S A 114:2355-2360
Peng, Hui; Shen, Jiangchuan; Edmonds, Katherine A et al. (2017) Sulfide Homeostasis and Nitroxyl Intersect via Formation of Reactive Sulfur Species in Staphylococcus aureus. mSphere 2:

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