Caries and periodontitis are major oral diseases, both widespread and serious. Caries is thought to be caused by multifactorial, lifestyle-related factors as well as the genetic background of the patient. However, little is known about relevant genetic factors. Since the quality and quantity of enamel plays a direct role in the susceptibility to caries, we set out our quest for genetic factors from the two proteins crucial to the formation of dental enamel: amelogenin and enamelin. We isolated genomic DNAs from lingual mucosal cells derived from healthy and caries subjects, and examined the frequency of single nucleotide polymorphisms (SNPs) by the polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP) method. We focused on the SNPs of the amelogenin gene (AMELX) at positions ‫782ם‬ and ‫225ם‬ (in both cases, a C to T substitution), and on position ‫2542ם‬ position of the enamelin gene (ENAM; here, too, a C to T substitution). The subjects were all of Japanese extraction, of which 67 individuals served as healthy controls and 80 patients with severe caries served as test subjects. The occurrence of the substitutions at AMELX(‫,)782ם‬ ‫)225ם(‬ and ENAM(‫)2542ם‬ were 12.2, 0.0 and 11.9% in the control group, and 2.5, 0.0 and 5.0% in the caries group, respectively. The P-values for the statistical frequency of SNPs for AMELX(‫)782ם‬ and ENAM(‫)2542ם‬ were 0.142 and 0.143, respectively. Our data suggest that there was no significant association between the SNPs of those genes and caries susceptibility in the Japanese pediatric population.reported that levels of ␣-defensin 1-3 (an antimicrobial peptides from saliva) were significantly higher in children with no caries than in those with caries, in contrast to cathelicidin LL37 and ␤-defensin 3 3) . Thus, dental caries is a multifactorial disease. Amelogenins are extracellular matrix proteins which make up 90% of the enamel organic matrix. They are expressed specifically in the developing tooth bud and cleaved in a regulated process during enamel maturation 4,5) . Amelogenin proteins have been implicated in the control of enamel crystal growth, but their precise role has not yet been defined 6) . Amelogenin proteins also inhibit apatite

Histatins, a family of salivary proteins, have antimicrobial activity. Candida albicans, which is killed by histatins, induces oral candidiasis in individuals with compromised immune systems. Although the functional significance of histatins has been documented, their biological and physiological functions against host cells have not been clarified. In this study, we found that histatin 3, a member of the histatin family, binds to heat shock cognate protein 70 (HSC70). These proteins were co-localized in the cytoplasm and nucleus in human gingival fibroblasts following non-heat and heat shock. Histatin 3 induced stimulation of DNA synthesis and cell survival in human gingival fibroblasts in a dose-dependent manner. This DNA synthesis was found to be dependent on HSC70 by knockdown experiments. The effect of heat shock on DNA synthesis induced by histatin 3 was ϳ2-fold higher than that of non-heat shock. When the histatin 3 uptake into cells was inhibited by monodansylcadaverine or when histatin 3 binding to HSC70 was precluded by 15-deoxyspergualin, DNA synthesis by histatin 3 was ϳ2-fold less than that without monodansylcadaverine or 15-deoxyspergualin. Although HSC70 directly bound to p27Kip1 (a cyclin-dependent kinase inhibitor), histatin 3 increased the binding between those proteins but not with a peptide capable of binding to HSC70. Moreover histatin 3 prevented ATP-dependent dissociation of HSC70-p27 Kip1 . ATP was unable to form a histatin 3-HSC70(D10N)-p27Kip1 complex (HSC70(D10N) is a mutant attenuating ATPase activity). These findings suggest that histatin 3 may be involved in cell proliferation through the regulation of HSC70 and p27Kip1 in oral cells.Oral non-immune defense is associated with saliva. Some salivary proteins, such as histatins, have antibacterial and antifungal activities and protect oral tissues from pathogenic microorganisms (1). The histatin family of proteins, consisting of 12 members that are histidine-rich and consist of cationic 3-4-kDa proteins found in the saliva secreted by the salivary glands of humans and higher primates, are localized in human oral tissues (2-7). Histatins in saliva are also present in healthy adults at concentrations of 50 -425 g/ml (8). Histatins 1 and 3 are full-length proteins of 38 and 32 amino acids in length, respectively. Histatin 5 comprises 24 amino acids and is either a proteolytic product of histatin 3 or a protein translated from a post-transcriptionally modified histatin 3 mRNA (3). Other members of the histatin family are also generated by proteolytic degradation during secretion and have been characterized (9, 10). Histatins 3 and 5 exhibit antimicrobial activity against Candida albicans at physiological concentrations of 15-50 M (2, 11-13). In addition, histatin 5 has been shown to inhibit a trypsin-like protease and the cysteine protease clostripain, which are produced by Bacteroides gingivalis (an oral bacterium suspected of being the pathogen of periodontal disease) and Clostridium histolyticum, respectively (14, 15).A wide variety of...

These results suggest that CS exposure has adverse impacts on salivary composition and SGs, which could aggravate the oral environment.

Histatins are salivary proteins found and expressed in human salivary glands. They play a role in the non-immune system of antimicrobial defense, for instance, against Candida albicans. The transcriptional regulatory sequences of the histatin gene, HIS1, have remained obscure for a long time. Here, we cloned the putative promoter from human genomic DNA and tested it in a luciferase reporter system. This promoter is much more active in salivary gland cells than in other cell types. Analysis of deletion mutants revealed that the region encompassing -2254 to -1748 is a strong positive transcriptional element, and its functional core sequence (termed HTN27 box) works in correct and reverse orientations in synergy with downstream sequences, the region spanning -680 to +28 and a proximal promoter. The plus single-stranded HTN27 box is specifically bound by a 100 kDa protein that is present in HSG cells, but not in HeLa cells. These findings indicate that the regulation of the histatin gene expression may be intricate, and it seems to have a cell-type preference in the salivary gland cells.

Periodontitis is a widespread and serious dental disease that results from multifactorial and lifestyle-related causes. Patients with Down syndrome have a high risk of periodontal disease from an early age, but little is known about the genetic factors that may cause or exacerbate it. With this regard, we isolated DNAs from lingual mucosal cells and examined the frequency of specific single nucleotide polymorphisms (SNPs) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The SNPs on which we focused were of the pro-inflammatory cytokine genes Interleukin (IL)-1A(‫)988מ‬ and IL-1B(‫,)3593ם‬ and of the Toll-like receptor genes (TLR)2(Arg677Trp) and TLR4(Asp299Gly). The subjects of the study, all of Japanese extraction, were: (i) 18 individuals with Down syndrome and periodontitis; (ii) 10 individuals with Down syndrome and no periodontitis; (iii) 20 control individuals without Down syndrome but with periodontitis; and (iv) 10 control individuals without periodontitis. The patterns of occurrence of SNPs of the IL-1A, IL-1B, TLR2 and TLR4 were similar in all groups.