Pseudomonas aeruginosa is an opportunistic human pathogen that causes severe, life threatening infections in patients with cystic fibrosis (CF), endocarditis, wounds, artificial implants, and in healthcare-associated infections. The versatility of P. aeruginosa pathogenicity is associated with an outstanding physiological adaptability of the organism and its ability to modulate host responses, due in part to a tightly coordinated regulation of gene expression. Therefore, to gain control over currently untreatable Pseudomonas infections, it is critically important to generate new knowledge of the regulatory circuits coordinating the pathogen virulence in response to host factors. Calcium ion (Ca2+) is an essential intracellular messenger in eukaryotic cells, regulating vital cellular processes. It accumulates in pulmonary fluids of CF patients and in mitral annulus of endocarditis patients. Alterations in the host Ca2+ homeostasis may serve as a trigger for enhanced virulence of invading pathogens. In support, we showed that Ca2+ positively regulates biofilm formation, swarming, and production of several virulence factors in P. aeruginosa. However, the molecular mechanisms of such regulation are not known. It is also not known whether intracellular Ca2+ plays role as a second messenger in prokaryotes as it does in eukaryotes. Understanding the mechanisms of Ca2+ regulation, signaling and homeostasis will provide novel means for controlling P. aeruginosa viability, virulence, and interactions with the host. Earlier, we identified two putative Ca2+-binding proteins EfhP and CarP, mutations in which cause multiple Ca2+-dependent defects in virulence and infectivity. EfhP contains two EF-hand motives, known to bind Ca2+ and relay Ca2+ signal through conformational changes. CarP is predicted to form a beta-propeller and has a putative phytase domain. Based on the bioinformatics and preliminary studies, we hypothesize that EfhP and CarP provide different routes of Ca2+ signal transduction regulating virulence and host- pathogen interactions in response to Ca2+ in a host. To test this, we propose to determine the cellular localization and identify binding partners and signal-transducing pathways regulated by the two proteins. We will also characterize the role of EfhP and CarP in P. aeruginosa interactions with a host, and define their involvement in the development of acute and chronic infections. By utilizing the expertise of three OCRID core facilities, we will unravel the mechanisms of Ca2+ signaling and its role in regulating the ability of P. aeruginosa to cause infections at the molecular, cellular, and organismal level. This research is highly innovative as for the first time it will experimentally demonstrate Ca2+ signaling in bacteria, identify the components of Ca2+ signal transduction pathways, and define the role of Ca2+ signaling in P. aeruginosa pathogenicity in vivo.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Exploratory Grants (P20)
Project #
5P20GM103648-07
Application #
9745625
Study Section
Special Emphasis Panel (ZGM1)
Project Start
Project End
Budget Start
2019-07-01
Budget End
2020-06-30
Support Year
7
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Oklahoma State University Stillwater
Department
Type
DUNS #
049987720
City
Stillwater
State
OK
Country
United States
Zip Code
74078
Ektate, Kalyani; Munteanu, Maria Cristina; Ashar, Harshini et al. (2018) Chemo-immunotherapy of colon cancer with focused ultrasound and Salmonella-laden temperature sensitive liposomes (thermobots). Sci Rep 8:13062
Haghnegahdar, Ahmadreza; Feng, Yu; Chen, Xiaole et al. (2018) Computational Analysis of Deposition and Translocation of Inhaled Nicotine and Acrolein in the Human Body with E-cigarette Puffing Topographies. Aerosol Sci Technol 52:483-493
Zhu, Liqian; Jones, Clinton (2018) The canonical Wnt/?-catenin signaling pathway stimulates herpes simplex virus 1 productive infection. Virus Res 256:29-37
Ashar, Harshini K; Mueller, Nathan C; Rudd, Jennifer M et al. (2018) The Role of Extracellular Histones in Influenza Virus Pathogenesis. Am J Pathol 188:135-148
Patil, Girish; Zhao, Mengmeng; Song, Kun et al. (2018) TRIM41-Mediated Ubiquitination of Nucleoprotein Limits Influenza A Virus Infection. J Virol 92:
Senavirathna, Lakmini Kumari; Huang, Chaoqun; Yang, Xiaoyun et al. (2018) Hypoxia induces pulmonary fibroblast proliferation through NFAT signaling. Sci Rep 8:2709
Booth, J Leland; Duggan, Elizabeth S; Patel, Vineet I et al. (2018) Gene expression profiling of primary human type I alveolar epithelial cells exposed to Bacillus anthracis spores reveals induction of neutrophil and monocyte chemokines. Microb Pathog 121:9-21
Maria, Zahra; Lacombe, VĂ©ronique A (2018) Quantification of Cell-Surface Glucose Transporters in the Heart Using a Biotinylated Photolabeling Assay. Methods Mol Biol 1713:229-240
Workman, Aspen; Zhu, Liqian; Keel, Brittney N et al. (2018) The Wnt Signaling Pathway Is Differentially Expressed during the Bovine Herpesvirus 1 Latency-Reactivation Cycle: Evidence That Two Protein Kinases Associated with Neuronal Survival, Akt3 and BMPR2, Are Expressed at Higher Levels during Latency. J Virol 92:
McGill, Jodi L; Wang, Ying; Ganta, Chanran K et al. (2018) Antigen-Specific CD4+CD8+ Double-Positive T Cells Are Increased in the Blood and Spleen During Ehrlichia chaffeensis Infection in the Canine Host. Front Immunol 9:1585

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