Molecule Targeting Glucosyltransferase Inhibits Streptococcus mutans Biofilm Formation and Virulence.
Dental plaque biofilms are responsible for numerous chronic oral infections and cause a severe health burden. Many of these infections cannot be eliminated, as the bacteria in the biofilms are resistant to the host's immune defenses and antibiotics. There is a critical need to develop new strategies to control biofilm-based infections. Biofilm formation in Streptococcus mutans is promoted by major virulence factors known as glucosyltransferases (Gtfs), which synthesize adhesive extracellular polysaccharides (EPS). The current study was designed to identify novel molecules that target Gtfs, thereby inhibiting S. mutans biofilm formation and having the potential to prevent dental caries. Structure-based virtual screening of approximately 150,000 commercially available compounds against the crystal structure of the glucosyltransferase domain of the GtfC protein from S. mutans resulted in the identification of a quinoxaline derivative, 2-(4-methoxyphenyl)-N-(3-{[2-(4-methoxyphenyl)ethyl]imino}-1,4-dihydro-2-quinoxalinylidene)ethanamine, as a potential Gtf inhibitor. In vitro assays showed that the compound was capable of inhibiting EPS synthesis and biofilm formation in S. mutans by selectively antagonizing Gtfs instead of by killing the bacteria directly. Moreover, the in vivo anti-caries efficacy of the compound was evaluated in a rat model. We found that the compound significantly reduced the incidence and severity of smooth and sulcal-surface caries in vivo with a concomitant reduction in the percentage of S. mutans in the animals' dental plaque (P < 0.05). Taken together, these results represent the first description of a compound that targets Gtfs and that has the capacity to inhibit biofilm formation and the cariogenicity of S. mutans.
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Zhi
Z
Ren
State Key Laboratory of Agricultural Microbiology, Center for Proteomics Research, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, People's Republic of China.
Tao
T
Cui
Department of Structural Biology, Key Laboratory of Applied and Environmental Microbiology, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, People's Republic of China.
Jumei
J
Zeng
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Lulu
L
Chen
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Wenling
W
Zhang
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Xin
X
Xu
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Lei
L
Cheng
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Mingyun
M
Li
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Jiyao
J
Li
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China.
Xuedong
X
Zhou
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China liyuqing@scu.edu.cn.
Yuqing
Y
Li
D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D018360:Crystallography, X-Ray; D003731:Dental Caries / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D055808:Drug Discovery; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D015870:Gene Expression; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D057166:High-Throughput Screening Assays; D006801:Humans; D062105:Molecular Docking Simulation; D011810:Quinoxalines / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology; D013295:Streptococcus mutans / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D014584:User-Computer Interface; D037521:Virulence Factors / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D011810:Quinoxalines; D054852:Small Molecule Libraries; D037521:Virulence Factors; D005964:Glucosyltransferases