Effect of genetic polymorphisms in CA6 gene on the expression and catalytic activity of human salivary carbonic anhydrase VI

Sucrose rinse modulates the salivary behavior of carbonic anhydrase VI and its buffering capacity: a longitudinal study in 4 to 6.5-year-old children

Background

Carbonic anhydrase VI (CA VI) is crucial in regulating oral pH and predicting susceptibility to dental caries. The hypothesis posits that caries activity may alter the CA VI function, diminishing its capacity to regulate pH effectively and potentially exacerbating cariogenic challenges. This 1-year cohort study sought to investigate the enzymatic activity of salivary CA VI and buffering capacity following a 20% sucrose rinse in 4 to 6.5-year-old children.

Method

This research involved 46 volunteers categorized into three groups based on their caries status after follow-up: caries-free (CFee), arrested caries (CArrested), and caries active (CActive). Children underwent visible biofilm examination and saliva collection for salivary flow rate, buffering capacity, and CA VI analyses before and after a 20% sucrose rinse.

Results

A reduction in the buffering capacity was observed after sucrose rinse in all groups. The CA VI activity decreased significantly in CFee and CArrested groups after sucrose rinse, although it did not change in the CActive group. An improvement in the buffering capacity and salivary flow rate was found at follow-up when compared with the baseline. After 1-year follow-up, buffering capacity and salivary flow rate increased in all groups, whilst the CA VI activity reduced only in CFree and CArrested children.

Conclusion

Sucrose rinse universally reduces the salivary buffering capacity, while caries activity may disrupt CA VI activity response during a cariogenic challenge. After a year, increased salivary flow enhances buffering capacity but not CA VI activity in caries-active children.

Carbonic Anhydrases in Metazoan Model Organisms: Molecules, Mechanisms, and Physiology

During the past three decades, mice, zebrafish, fruit flies, and Caenorhabditis elegans have been the primary model organisms used for the study of various biological phenomena. These models have also been adopted and developed to investigate the physiological roles of carbonic anhydrases (CAs) and carbonic anhydrase-related proteins (CARPs). These proteins belong to eight CA families and are identified by Greek letters: α, β, γ, δ, ζ, η, θ, and ι. Studies using model organisms have focused on two CA families, α-CAs and β-CAs, which are expressed in both prokaryotic and eukaryotic organisms with species-specific distribution patterns and unique functions. This review covers the biological roles of CAs and CARPs in light of investigations performed in model organisms. Functional studies demonstrate that CAs are not only linked to the regulation of pH homeostasis, the classical role of CAs but also contribute to a plethora of previously undescribed functions.

The role of mechanical control of biofilm in the salivary pH after sucrose exposure in children with early childhood caries

This quasi-experimental study sought to investigate if the mechanical control of biofilm (3-times-a-day) modifies the saliva’s ability to buffer the oral environment after 20% sucrose rinse (SR_20%) in children with early childhood caries (ECC). Here, SR_20% reduced the saliva’s pH in both groups and the mechanical control of biofilm had a greater effect on this parameter after SR_20% in CF children. The mechanical control of biofilm evidenced a higher buffering capacity in CF children before SR_20%, which was not observed after SR_20%. Otherwise, the absence of mechanical control of biofilm showed that buffering capacity was comparable in the two groups before SR_20%, whereas after SR_20% the saliva’s buffering capacity of CF children was higher than ECC children. When biofilm was mechanically controlled, carbonic anhydrase VI activity did not change after SR_20% whereas the absence of mechanical control of biofilm reduced this enzyme activity after SR_20%. In conclusion, the mechanical control of biofilm did not change saliva’s ability to buffer the oral environment after SR_20% in children with ECC. On the other hand, CF children appeared to regulate more effectively the saliva’s pH than ECC children while the absence of mechanical control of biofilm mediated their pH-modifying ability after SR_20%.

Investigation of carbonic anhydrase 6 gene polymorphism rs2274327 in relation to the oral health status and salivary composition in type 2 diabetic patients

OBJECTIVE

The aim of the present study was to investigate the oral manifestations and salivary composition in type 2 diabetics with periodontitis and to evaluate their association with CA6 gene polymorphism rs2274327.

METHODS

Oral examination was performed by a single periodontist for 300 type 2 diabetics. Whole unstimulated saliva and blood were collected. The salivary pH, buffer capacity and flow rate were later measured. Immunoglobulin A and electrolytes were assessed using an autoanalyzer. CA6 gene polymorphism rs2274327 was screened by PCR-RFLP assay. The statistical analysis was performed using the SPSS 20.0 version.

RESULTS

The salivary pH, buffer capacity and flow rate were significantly lower in the patients carrying TT genotype compared to CC and CT genotype carriers (p < .05). Furthermore, the DMFT index, OHI-s, PI, PPD and CAL were significantly higher in the subjects with TT genotype (p < .05). Carrying at least one T allele seemed to increase the risk of dental caries (OR = 2.59, p < .001), xerostomia (OR = 2.11, p=.003) and taste impairment (OR = 1.97, p < .05).

CONCLUSION

CA6 gene polymorphism rs2274327 seemed to increase the risk of developing, dental caries, periodontitis, xerostomia and taste impairment in type 2 diabetics.

Combined effect of starch and sucrose on carbonic anhydrase VI activity in saliva and biofilm of children with early childhood caries. Exposure to starch and sucrose alters carbonic anhydrase VI activity in saliva and biofilm

OBJECTIVES

This study aimed to investigate whether combined exposure to starch and sucrose modifies the activity of carbonic anhydrase VI (CA VI) in saliva (Study 1) and biofilm (Study 2) of children with early childhood caries (ECC).

MATERIAL AND METHODS

For Study 1 and Study 2, respectively, 54 and 46 preschoolers aged 4 to 5 were allocated into two groups: caries-free (CF) and with ECC. Children were exposed to rinses with sucrose, starch, and sucrose plus starch solutions. CA VI activity, pH, and buffering capacity (BC) were evaluated in saliva and biofilm.

RESULTS

In Study 1, a significant reduction in saliva pH was observed after sucrose and sucrose plus starch rinses. CA VI activity was influenced by ECC independently of the type of carbohydrate to which children were exposed. CA VI activity was higher in children with ECC; however, after rinses, CA VI activity was reduced. In Study 2, biofilm pH and BC were reduced after rinses with sucrose and sucrose plus starch. CA VI activity was significantly high before rinse in ECC group when compared with CF group; however, no difference was observed between groups after rinses.

CONCLUSIONS

In saliva, exposure to starch and sucrose (isolated or combined) induced a reduction in CA VI activity in children with ECC. In biofilm, the combination of starch and sucrose did not modify CA VI activity in ECC children.

CLINICAL RELEVANCE

The responsivity of the CA VI reflects directly in important parameters related to the pH maintenance on the oral cavity.

Polymorphism in the CAVI gene, salivary properties and dental caries

Objectives: Carbonic anhydrase (CA) VI is supposed to take part in pH or buffering capacity regulation, which can influence the caries risk of an individual. Its expression in the saliva can be modified by single nucleotide polymorphism (SNP). The aim was to investigate SNP in the CA VI gene in relation to active dental caries and physiochemical properties of saliva.Materials and methods: One hundred and thirty participants aged 11-16 years were involved. Clinical examinations were carried out using standardized WHO criteria, DMFT/DMFS and white spot lesions score was evaluated. Saliva samples were examined for salivary properties and CA VI concentration. DNA evaluated in the investigation was extracted from the buccal smear. Three SNP within CAVI gene (rs2274327; rs2274328; rs2274333) were selected and genotyping was performed.Results: In the active caries group, the mean CAVI concentration was significantly lower than in caries free group (p = .014). No association between increased or decreased risk of caries and analysed SNPs was found. There were some significant relations concerning SNPs and salivary buffer capacity and flow rate in rs2274327 and rs2274328.Conclusions: Polymorphism in the CAVI gene can affect salivary properties but there is no direct connection with dental caries.

Analysis of salivary factors related to the oral health status in children

Early detection of oral disease is important to reduce its severity and increase the likelihood of successful treatment. This study aimed to perform a quantitative assessment of the saliva components as a first stage of the research to screen oral homeostasis. Here, saliva secretions collected from children were evaluated, and their constituents were analyzed to investigate the potential correlations between the buffering capacity and a range of salivary factors. Subjects aged 3-16 years in the primary, mixed, or permanent dentition stage, were selected for this study. The following salivary factors were analyzed: flow rate, total protein, total sugar quantifications, and constituent analyses using RT-PCR and western blotting. The associations between each factor and the buffering capacity were then analyzed using multiple regression analysis. Flow rate, BPIFA2 RNA level, histatin 1 and BPIFB1 protein levels as well as female sex were positively associated with buffering capacity. In contrast, total sugar concentration and MUC7 RNA levels showed a negative relationship with the buffering capacity. Some of these constituents may indicate oral homeostasis and are therefore potential biomarkers of oral health status. These results suggest that the analyses of the correlations between oral homeostasis and salivary factors are an effective strategy for identifying the susceptibility to oral diseases.

Carbonic Anhydrase 6 Gene Variation influences Oral Microbiota Composition and Caries Risk in Swedish adolescents

Carbonic anhydrase VI (CA6) catalyses the reversible hydration of carbon dioxide in saliva with possible pH regulation, taste perception, and tooth formation effects. This study assessed effects of variation in the CA6 gene on oral microbiota and specifically the acidophilic and caries-associated Streptococcus mutans in 17-year old Swedish adolescents (n = 154). Associations with caries status and secreted CA6 protein were also evaluated. Single Nucleotide Polymorphisms (27 SNPs in 5 haploblocks) and saliva and tooth biofilm microbiota from Illumina MiSeq 16S rDNA (V3-V4) sequencing and culturing were analysed. Haploblock 4 (rs10864376, rs3737665, rs12138897) CCC associated with low prevalence of S. mutans (OR (95% CI): 0.5 (0.3, 0.8)), and caries (OR 0.6 (0.3, 0.9)), whereas haploblock 4 TTG associated with high prevalence of S. mutans (OR: 2.7 (1.2, 5.9)) and caries (OR: 2.3 (1.2, 4.4)). The TTG-haploblock 4 (represented by rs12138897(G)) was characterized by S. mutans, Scardovia wiggsiae, Treponema sp. HOT268, Tannerella sp. HOT286, Veillonella gp.1 compared with the CCC-haploblock 4 (represented by rs12138897(C)). Secreted CA6 in saliva was weakly linked to CA6 gene variation. In conclusion, the results indicate that CA6 gene polymorphisms influence S. mutans colonization, tooth biofilm microbiota composition and risk of dental caries in Swedish adolescents.

The Role of Genetic Factors in the Outbreak Mechanism of Dental Caries

OBJECTIVE

The aim of the present study was to investigate the relationships between cariogenic bacterial infection and single nucleotide polymorphisms (SNPs) in candidate genes associated with dental caries, and to explore the factors related to caries in children.

STUDY DESIGN

Children aged 3 to 11 years were selected. Detection of cariogenic bacteria (Streptococcus mutans, Streptococcus oralis, Streptococcus sobrinus and Lactobacillus) from the plaque of each patient, and SNP analyses of five candidate genes (MBL2, TAS2R38, GLUT2, MMP13 and CA6) were performed using DNA isolated from buccal mucosal cells. The dental caries experience in primary and permanent teeth was determined using the decayed, missing and filled teeth (DMFT) index, and the effects of the observed factors on the DMFT value were analyzed by multiple regression analysis.

RESULTS

The results of the multiple regression analysis showed that the DMFT value significantly increased in the presence of S. mutans or S. sobrinus (p < 0.001), while the dmft/DMFT value decreased in the presence of nucleobase C in MBL2 (p < 0.05).

CONCLUSION

These results suggest that the MBL2 gene is related to the pathogenesis of dental caries.

Variants in Chemosensory Genes Are Associated with Picky Eating Behavior in Preschool-Age Children

BACKGROUND/AIMS

Picky eating is prevalent among preschoolers and is associated with risk of both underweight and overweight. Although differences in taste perception may be due to genetic variation, it is unclear whether these variations are related to picky eating behavior. The aim of this study was to investigate the association of 6 single nucleotide polymorphisms (SNPs) in 5 candidate genes related to chemosensory perception with picky eating behavior and adiposity in a cohort of preschool-aged children.

METHODS

Parents of 2- to 5-year-old non-Hispanic white preschoolers (n = 153) responded to survey questions on demographics, and information regarding their child's breastfeeding history and picky eating behavior. Height and weight were measured to calculate body mass index (BMI) z-scores using standard growth charts, and saliva was collected for genotyping. Generalized linear models were used to examine associations between picky eating behavior and BMI z-scores with genetic variation.

RESULTS

When controlling for child age, sex, breastfed status, and parent education level, SNPs in TAS2R38 (rs713598) and CA6 (rs2274327) were associated with picky eating behavior in children. There was no association between SNPs and BMI z-scores.

CONCLUSION

Genes related to chemosensory perception may play a role in children's picky eating behavior.

Carbonic Anhydrase VI Gene Polymorphism rs2274327 Relationship Between Salivary Parameters and Dental-Oral Health Status in Children

The aim of this study was to research carbonic anhydrase (CA) VI one single-nucleotide polymorphism (SNP) and its potential association with dental-oral health status (dental caries, Plaque Index (PI) and Gingival Index (GI)) and salivary parameters (salivary buffering capacity, salivary flow rate (SFR)) in children. A total of 178 children were divided into two groups: non-carious (n = 70, 34 boys and 36 girls) and carious (n = 108, 47 boys and 61 girls). The clinical evaluations were performed according to the decayed, missing, and filled teeth (dmft/DMFT) index by a specialist. Clinical parameters including PI, GI, and simplified oral hygiene index (OHI-S) were recorded. Salivary pH (SpH) was measured using pH paper. Blood samples and unstimulated whole saliva were collected, and SFR was calculated. The CA VI rs2274327 polymorphism was determined by a LightSNiP assay on the realtime PCR system. The frequencies of rs2274327 were not significant between groups (p > 0.05). There was a positive correlation between OHI-S and SpH in the carious and non-carious groups (p < 0.05). There was no correlation among the SNPs' frequencies and OHI-S, PI, GI, SFR, and SpH (p > 0.05). CA VI SNP (rs2274327) had no statistically significant association with OHI-S, PI, GI, SFR, and SpH in the children.

Mass spectrometry-based analyses showing the effects of secretor and blood group status on salivary N-glycosylation

Background

The carbohydrate portions of salivary glycoproteins play important roles, including mediating bacterial and leukocyte adhesion. Salivary glycosylation is complex. Many of its glycoproteins present ABO and Lewis blood group determinants. An individual’s genetic complement and secretor status govern the expression of blood group antigens. We queried the extent to which salivary glycosylation varies according to blood group and secretor status. First, we screened submandibular/sublingual and parotid salivas collected as ductal secretions for reactivity with a panel of 16 lectins. We selected three lectins that reacted with the largest number of glycoproteins and one that recognized uncommon lactosamine-containing structures. Ductal salivas representing a secretor with complex blood group expression and a nonsecretor with a simple pattern were separated by SDS-PAGE. Gel slices were trypsin digested and the glycopeptides were individually separated on each of the four lectins. The bound fractions were de-N-glycosylated. LC–MS/MS identified the original glycosylation sites, the peptide sequences, and the parent proteins.

Results

The results revealed novel salivary N-glycosites and glycoproteins not previously reported. As compared to the secretor, nonsecretor saliva had higher levels of N-glycosylation albeit with simpler structures.

Conclusions

Together, the results suggested a molecular basis for inter-individual variations in salivary protein glycosylation with functional implications for oral health.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9100-y) contains supplementary material, which is available to authorized users.

Cloning, characterization and anion inhibition study of a β-class carbonic anhydrase from the caries producing pathogen Streptococcus mutans

The oral pathogenic bacterium involved in human dental caries formation Streptococcus mutans, encodes for two carbonic anhydrase (CA, EC 4.2.1.1) one belonging to the α- and the other one to the β-class. This last enzyme (SmuCA) has been cloned, characterized and investigated for its inhibition profile with a major class of CA inhibitors, the inorganic anions. Here we show that SmuCA has a good catalytic activity for the CO2 hydration reaction, with kcat 4.2×10(5)s(-1) and kcat/Km of 5.8×10(7)M(-1)×s(-1), being inhibited by cyanate, carbonate, stannate, divannadate and diethyldithiocarbamate in the submillimolar range (KIs of 0.30-0.64mM) and more efficiently by sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid (KIs of 15-46μM). The anion inhibition profile of the S. mutans enzyme is very different from other α- and β-CAs investigated earlier. Identification of effective inhibitors of this new enzyme may lead to pharmacological tools useful for understanding the role of S. mutans CAs in dental caries formation, and eventually the development of pharmacological agents with a new mechanism of antibacterial action.

Sulfonamide inhibition study of the β-class carbonic anhydrase from the caries producing pathogen Streptococcus mutans

Streptococcus mutans, the oral pathogenic bacterium provoking dental caries formation, encodes for a β-class carbonic anhydrase (CA, EC 4.2.1.1), SmuCA. This enzyme was cloned, characterized and investigated for its inhibition profile with the major class of CA inhibitors, the primary sulfonamides. SmuCA has a good catalytic activity for the CO2 hydration reaction, with a kcat of 4.2×10(5) s(-1) and kcat/Km of 5.8×10(7) M(-1)×s(-1), and is efficiently inhibited by most sulfonamides (KIs of 246 nM-13.5 μM). The best SmuCA inhibitors were bromosulfanilamide, deacetylated acetazolamide, 4-hydroxymethylbenzenesulfonamide, a pyrimidine-substituted sulfanilamide derivative, aminobenzolamide and compounds structurally similar to it, as well as acetazolamide, methazolamide, indisulam and valdecoxib. These compounds showed inhibition constants ranging between 246 and 468 nM. Identification of effective inhibitors of this enzyme may lead to pharmacological tools useful for understanding the role of S. mutans CAs in dental caries formation, and eventually the development of pharmacological agents with a new mechanism of antibacterial action.

Can Saliva Proteins Be Used to Predict the Onset of Acute Myocardial Infarction among High-Risk Patients?

Human saliva plays a pivotal role in digesting food and maintaining oral hygiene. The presence of electrolytes, mucus, glycoproteins, enzymes, antibacterial compounds, and gingival crevicular fluid in saliva ensures the optimum condition of oral cavity and general health condition. Saliva collection has been proven non-invasive, convenient, and inexpensive compared to conventional venipuncture procedure. These distinctive advantages provide a promising potential of saliva as a diagnostic fluid. Through comprehensive analysis, an array of salivary proteins and peptides may be beneficial as biomarkers in oral and systemic diseases. In this review, we discuss the utility of human salivary proteomes and tabulate the recent salivary biomarkers found in subjects with acute myocardial infarction as well as respective methods employed. In a clinical setting, since acute myocardial infarction contributes to large cases of mortality worldwide, an early intervention using these biomarkers will provide an effective solution to reduce global heart attack incidence particularly among its high-risk group of type-2 diabetes mellitus patients. The utility of salivary biomarkers will make the prediction of this cardiac event possible due to its reliability hence improve the quality of life of the patients. Current challenges in saliva collection are also addressed to improve the quality of saliva samples and produce robust biomarkers for future use in clinical applications.

Genome wide screening of candidate genes for improving piglet birth weight using high and low estimated breeding value populations

Birth weight is an economically important trait in pig production because it directly impacts piglet growth and survival rate. In the present study, we performed a genome wide survey of candidate genes and pathways associated with individual birth weight (IBW) using the Illumina PorcineSNP60 BeadChip on 24 high (HEBV) and 24 low estimated breeding value (LEBV) animals. These animals were selected from a reference population of 522 individuals produced by three sires and six dam lines, which were crossbreds with multiple breeds. After quality-control, 43,257 SNPs (single nucleotide polymorphisms), including 42,243 autosomal SNPs and 1,014 SNPs on chromosome X, were used in the data analysis. A total of 27 differentially selected regions (DSRs), including 1 on Sus scrofa chromosome 1 (SSC1), 1 on SSC4, 2 on SSC5, 4 on SSC6, 2 on SSC7, 5 on SSC8, 3 on SSC9, 1 on SSC14, 3 on SSC18, and 5 on SSCX, were identified to show the genome wide separations between the HEBV and LEBV groups for IBW in piglets. A DSR with the most number of significant SNPs (including 7 top 0.1% and 31 top 5% SNPs) was located on SSC6, while another DSR with the largest genetic differences in F_ST was found on SSC18. These regions harbor known functionally important genes involved in growth and development, such as TNFRSF9 (tumor necrosis factor receptor superfamily member 9), CA6 (carbonic anhydrase VI) and MDFIC (MyoD family inhibitor domain containing). A DSR rich in imprinting genes appeared on SSC9, which included PEG10 (paternally expressed 10), SGCE (sarcoglycan, epsilon), PPP1R9A (protein phosphatase 1, regulatory subunit 9A) and ASB4 (ankyrin repeat and SOCS box containing 4). More importantly, our present study provided evidence to support six quantitative trait loci (QTL) regions for pig birth weight, six QTL regions for average birth weight (ABW) and three QTL regions for litter birth weight (LBW) reported previously by other groups. Furthermore, gene ontology analysis with 183 genes harbored in these 27 DSRs suggested that protein, metal, ion and ATP binding, viral process and innate immune response present important pathways for deciphering their roles in fetal growth or development. Overall, our study provides useful information on candidate genes and pathways for regulating birth weight in piglets, thus improving our understanding of the genetic mechanisms involved in porcine embryonic or fetal development.