Proteomic analysis of Porphyromonas gingivalis exposed to nicotine and cotinine.
OBJECTIVE
Smokers are more predisposed than nonsmokers to infection with Porphyromonas gingivalis, one of the most important pathogens involved in the onset and development of periodontitis. It has also been observed that tobacco, and tobacco derivatives such as nicotine and cotinine, can induce modifications to P. gingivalis virulence. However, the effect of the major compounds derived from cigarettes on expression of protein by P. gingivalis is poorly understood. Therefore, this study aimed to evaluate and compare the effects of nicotine and cotinine on the P. gingivalis proteomic profile.


METHODS
Total proteins of P. gingivalis exposed to nicotine and cotinine were extracted and separated by two-dimensional electrophoresis. Proteins differentially expressed were successfully identified through liquid chromatography-mass spectrometry and primary sequence databases using MASCOT search engine, and gene ontology was carried out using DAVID tools.


RESULTS
Of the approximately 410 protein spots that were reproducibly detected on each gel, 23 were differentially expressed in at least one of the treatments. A particular increase was seen in proteins involved in metabolism, virulence and acquisition of peptides, protein synthesis and folding, transcription and oxidative stress. Few proteins showed significant decreases in expression; those that did are involved in cell envelope biosynthesis and proteolysis and also in metabolism.


CONCLUSIONS
Our results characterized the changes in the proteome of P. gingivalis following exposure to nicotine and cotinine, suggesting that these substances may modulate, with minor changes, protein expression. The present study is, in part, a step toward understanding the potential smoke-pathogen interaction that may occur in smokers with periodontitis.
Department of Physiological Sciences, Area of Pharmacology, Anesthesiology and Therapeutics, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil. karicogo@hotmail.com
K
K
Cogo
A
A
de Andrade
C A
CA
Labate
C C
CC
Bergamaschi
L A
LA
Berto
G C N
GC
Franco
R B
RB
Gonçalves
F C
FC
Groppo
D001426:Bacterial Proteins / Q000032:analysis*; D003367:Cotinine / Q000494:pharmacology*; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D013058:Mass Spectrometry / Q000379:methods; D009538:Nicotine / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D016966:Porphyromonas gingivalis / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D014176:Protein Biosynthesis / Q000187:drug effects*; D020543:Proteome / Q000187:drug effects*; D014774:Virulence / Q000187:drug effects
D001426:Bacterial Proteins; D020543:Proteome; D009538:Nicotine; D003367:Cotinine