The role of the cytoplasmic heme‐binding protein (PhuS) of Pseudomonas aeruginosa in quorum sensing and intracellular iron homeostasis

Pseudomonas aeruginosa is an opportunistic pathogen requiring iron for its survival and virulence. P. aeruginosa can acquire iron from heme via the heme assimilation system (Has) and Pseudomonas heme uptake (Phu) systems. The Has and Phu systems have non-redundant roles in heme sensing and transport, respectively. However, despite their respective roles heme taken up by either the Has or Phu system is regulated at the metabolic level by the cytoplasmic heme binding protein PhuS, which controls heme flux through the iron-regulated heme oxygenase HemO. Herein, through a combination of CHIP-PCR, EMSA and fluorescence anisotropy we show PhuS binds upstream of the tandem iron-responsive sRNAs prrF1,F2. Furthermore, qPCR analysis of the PAO1 WT and ΔphuS allelic strain shows loss of PhuS abrogates the heme dependent regulation of PrrH. Taken together our data shows PhuS, in addition to its role in regulating extracellular heme metabolism also functions as a transcriptional regulator of the heme-dependent sRNA, PrrH. This dual function of PhuS is central to integrating extracellular heme utilization into the PrrF/PrrH sRNA regulatory network critical for P. aeruginosa adaptation and virulence within the host.

Download Full-text

What Is Next in This “Age” of Heme-Driven Pathology and Protection by Hemopexin? An Update and Links with Iron

Pharmaceuticals ◽

10.3390/ph12040144 ◽

2019 ◽

Vol 12 (4) ◽

pp. 144 ◽

Cited By ~ 5

Author(s):

Luis Montecinos ◽

Jeffrey D. Eskew ◽

Ann Smith

Keyword(s):

Immune System ◽

Iron Homeostasis ◽

Binding Protein ◽

Background Information ◽

Heme Binding ◽

Mediated Effects ◽

Immune System Activation ◽

Wide Range ◽

Health And Disease ◽

Heme Binding Protein

This review provides a synopsis of the published literature over the past two years on the heme-binding protein hemopexin (HPX), with some background information on the biochemistry of the HPX system. One focus is on the mechanisms of heme-driven pathology in the context of heme and iron homeostasis in human health and disease. The heme-binding protein hemopexin is a multi-functional protectant against hemoglobin (Hb)-derived heme toxicity as well as mitigating heme-mediated effects on immune cells, endothelial cells, and stem cells that collectively contribute to driving inflammation, perturbing vascular hemostasis and blood–brain barrier function. Heme toxicity, which may lead to iron toxicity, is recognized increasingly in a wide range of conditions involving hemolysis and immune system activation and, in this review, we highlight some newly identified actions of heme and hemopexin especially in situations where normal processes fail to maintain heme and iron homeostasis. Finally, we present preliminary data showing that the cytokine IL-6 cross talks with activation of the c-Jun N-terminal kinase pathway in response to heme-hemopexin in models of hepatocytes. This indicates another level of complexity in the cell responses to elevated heme via the HPX system when the immune system is activated and/or in the presence of inflammation.

Download Full-text

Ligand Induced Allostery in Pseudomonas Aeruginosa Cytoplasmic Heme Binding Protein (Phus) Drives the Protein-Protein Interaction with Heme Oxygenase

Biophysical Journal ◽

10.1016/j.bpj.2015.11.1225 ◽

2016 ◽

Vol 110 (3) ◽

pp. 221a

Author(s):

Daniel J. Deredge ◽

Weiliang Huang ◽

Colleen Hui ◽

Pierre Moenne-Loccoz ◽

Angela Wilks ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Heme Oxygenase ◽

Protein Interaction ◽

Binding Protein ◽

Heme Binding ◽

Protein Protein Interaction ◽

Heme Binding Protein

Download Full-text

Crystal structure of the Pseudomonas aeruginosa cytoplasmic heme binding protein, Apo-PhuS

Journal of Inorganic Biochemistry ◽

10.1016/j.jinorgbio.2013.07.030 ◽

2013 ◽

Vol 128 ◽

pp. 131-136 ◽

Cited By ~ 8

Author(s):

Sarvind Tripathi ◽

Maura J. O'Neill ◽

Angela Wilks ◽

Thomas L. Poulos

Keyword(s):

Crystal Structure ◽

Pseudomonas Aeruginosa ◽

Binding Protein ◽

Heme Binding ◽

Heme Binding Protein

Download Full-text

Regulation of Iron Homeostasis Mediated by the Heme-binding Protein Dap1 (Damage Resistance Protein 1) via the P450 Protein Erg11/Cyp51

Journal of Biological Chemistry ◽

10.1074/jbc.m706770200 ◽

2007 ◽

Vol 282 (50) ◽

pp. 36543-36551 ◽

Cited By ~ 36

Author(s):

Rolf J. Craven ◽

Julia C. Mallory ◽

Randal A. Hand

Keyword(s):

Iron Homeostasis ◽

Binding Protein ◽

Heme Binding ◽

Damage Resistance ◽

Resistance Protein ◽

Heme Binding Protein

Download Full-text

Faculty Opinions recommendation of Heme-binding protein HRG-1 is induced by insulin-like growth factor I and associates with the vacuolar H+-ATPase to control endosomal pH and receptor trafficking.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1356957.828056 ◽

2009 ◽

Author(s):

Michael Roth

Keyword(s):

Growth Factor ◽

Binding Protein ◽

Receptor Trafficking ◽

Insulin Like Growth Factor ◽

Heme Binding ◽

Factor I ◽

Endosomal Ph ◽

Growth Factor I ◽

Heme Binding Protein

Download Full-text

Sub-Inhibitory Concentrations of Ciprofloxacin Alone and Combinations with Plant-Derived Compounds against P. aeruginosa Biofilms and Their Effects on the Metabolomic Profile of P. aeruginosa Biofilms

Antibiotics ◽

10.3390/antibiotics10040414 ◽

2021 ◽

Vol 10 (4) ◽

pp. 414

Author(s):

Didem Kart ◽

Tuba Reçber ◽

Emirhan Nemutlu ◽

Meral Sagiroglu

Keyword(s):

Pseudomonas Aeruginosa ◽

Quorum Sensing ◽

Inhibitory Concentration ◽

Molecular Level ◽

Metabolomic Profile ◽

Gene Expressions ◽

New Agents ◽

Qrt Pcr ◽

Metabolomic Approach

Introduction: Alternative anti-biofilm agents are needed to combat Pseudomonas aeruginosa infections. The mechanisms behind these new agents also need to be revealed at a molecular level. Materials and methods: The anti-biofilm effects of 10 plant-derived compounds on P. aeruginosa biofilms were investigated using minimum biofilm eradication concentration (MBEC) and virulence assays. The effects of ciprofloxacin and compound combinations on P. aeruginosa in mono and triple biofilms were compared. A metabolomic approach and qRT-PCR were applied to the biofilms treated with ciprofloxacin in combination with baicalein, esculin hydrate, curcumin, and cinnamaldehyde at sub-minimal biofilm inhibitory concentration (MBIC) concentrations to highlight the specific metabolic shifts between the biofilms and to determine the quorum sensing gene expressions, respectively. Results: The combinations of ciprofloxacin with curcumin, baicalein, esculetin, and cinnamaldehyde showed more reduced MBICs than ciprofloxacin alone. The quorum sensing genes were downregulated in the presence of curcumin and cinnamaldehyde, while upregulated in the presence of baicalein and esculin hydrate rather than for ciprofloxacin alone. The combinations exhibited different killing effects on P. aeruginosa in mono and triple biofilms without affecting its virulence. The findings of the decreased metabolite levels related to pyrimidine and lipopolysaccharide synthesis and to down-regulated alginate and lasI expressions strongly indicate the role of multifactorial mechanisms for curcumin-mediated P. aeruginosa growth inhibition. Conclusions: The use of curcumin, baicalein, esculetin, and cinnamaldehyde with ciprofloxacin will help fight against P. aeruginosa biofilms. To the best of our knowledge, this is the first study of its kind to define the effect of plant-based compounds as possible anti-biofilm agents with low MBICs for the treatment of P. aeruginosa biofilms through metabolomic pathways.

Download Full-text