Oral colonization by Streptococcus mutans and caries development is reduced upon deletion of carbonic anhydrase VI expression in saliva

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1812

Article

Culp, David J.¹  Robinson, Bently¹  Parkkila, Seppo^2,3,4  Pan, Pei-wen^2,3,4  Cash, Melanie N.¹  Truong, Helen N.¹  Hussey, Thomas W.¹  Gullett, Sarah L.¹ 

[1] Univ Florida, Coll Dent, Dept Oral Biol, Gainesville, FL 32610 USA

[2] Univ Tampere, Inst Biomed Technol, Tampere 33014, Finland

[3] Univ Tampere, Sch Med, Tampere 33014, Finland

[4] Tampere Univ Hosp, Ctr Lab Med, Tampere 33521, Finland

关键词: Carbonic anhydrase;    Saliva;    Streptococcus mutans;    Oral colonization;    Nonsense-mediated decay;    Knockout mice;   

DOI  :  10.1016/j.bbadis.2011.09.006

来源: Elsevier

【 摘 要 】

Carbonic anhydrase VI (CA VI), encoded by type A transcripts of the gene Car6, is a secretory product of salivary glands and is found in the enamel pellicle. Because higher caries prevalence is associated with lower salivary concentrations of CA VI in humans, we tested whether CA VI protects enamel surfaces from caries induced by Streptococcus mutans, using Car6(-/-) mice, in which salivary CA VI expression is absent. We detected aberrant Car6 type A transcripts in Car6(-/-) mice, likely targets for nonsense-mediated mRNA decay. Expression of the intracellular stress-induced isoform of CA VI encoded by type B transcripts was restricted to parotid and submandibular glands of wild type mice. The salivary function of Car6(-/-) mice was normal as assessed by the histology and protein/glycoprotein profiles of glands, salivary flow rates and protein/glycoprotein compositions of saliva. Surprisingly, total smooth surface caries and sulcal caries in Car6(-/-) mice were more than 6-fold and 2-fold lower than in wild type mice after infection with S. mutans strain UA159. Recoveries of S. mutans and total microbiota from molars were also lower in Car6(-/-) mice. To explore possible mechanisms for increased caries susceptibility, we found no differences in S. mutans adherence to salivary pellicles, in vitro. Interestingly, higher levels of Lactobacillus murinus and an unidentified Streptococcus species were cultivated from the oral microbiota of Car6(-/-) mice. Collective results suggest salivary CA VI may promote caries by modulating the oral microbiota to favor S. mutans colonization and/or by the enzymatic production of acid within plaque. (C) 2011 Elsevier B.V. All rights reserved.

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