Role of estrogen related receptor beta (ESRRB) in DFN35B hearing impairment and dental decay

Identification of common stria vascularis cellular alteration in sensorineural hearing loss based on ScRNA-seq

BACKGROUND

The stria vascularis (SV), located in the lateral wall of the cochlea, maintains cochlear fluid homeostasis and mechanoelectrical transduction (MET) activity required for sound wave conduction. The pathogenesis of a number of human inheritable deafness syndromes, age related hearing loss, drug-induced ototoxicity and noise-induced hearing loss results from the morphological changes and functional impairments in the development of the SV. In this study, we investigate the implications of intercellular communication within the SV in the pathogenesis of sensorineural hearing loss (SNHL). We aim to identify commonly regulated signaling pathways using publicly available single-cell transcriptomic sequencing (scRNA-seq) datasets.

METHODS

We analyzed scRNA-seq data, which was derived from studying the cochlear SV in mice with SNHL compared to normal adult mice. After quality control and filtering, we obtained the major cellular components of the mouse cochlear SV and integrated the data. Using Seurat's FindAllMarkers and FindMarkers packages, we searched for novel conservative genes and differential genes. We employed KEGG and GSEA to identify molecular pathways that are commonly altered among different types of SNHL. We utilized pySCENIC to discover new specific regulatory factors in SV subpopulation cells. With the help of CellChat, we identified changes in subpopulation cells showing similar trends across different SNHL types and their alterations in intercellular communication pathways.

RESULTS

Through the analysis of the integrated data, we discovered new conserved genes to SV specific cells and identified common downregulated pathways in three types of SNHL. The enriched genes for these pathways showing similar trends are primarily associated with the Electron Transport Chain, related to mitochondrial energy metabolism. Using the CellChat package, we further found that there are shared pathways in the incoming signaling of specific intermediate cells in SNHL, and these pathways have common upstream regulatory transcription factor of Nfe2l2. Combining the results from pySCENIC and CellChat, we predicted the transcription factor Nfe2l2 as an upstream regulatory factor for multiple shared cellular pathways in IC. Additionally, it serves as an upstream factor for several genes within the Electron Transport Chain.

CONCLUSION

Our bioinformatics analysis has revealed that downregulation of the mitochondrial electron transport chain have been observed in various conditions of SNHL. E2f1, Esrrb, Runx1, Yy1, and Gata2 could serve as novel important common TFs regulating the electron transport chain. Adm has emerged as a potential new marker gene for intermediate cells, while Itgb5 and Tesc show promise as potential new marker genes for marginal cells in the SV. These findings offer a new perspective on SV lesions in SNHL and provide additional theoretical evidence for the same drug treatment and prevention of different pathologies of SNHL.

Oral microbiome-dental caries associated genotypes analysis of 6- to 19-year-old individuals shows novel associations

The need to determine risk factors for complex diseases continues to drive efforts of identification of etiological factors of common conditions. Molecular tools have created new opportunities to identify risk factors that may act interactively. The goal of this work was exploring potential interactions between oral microbial species and common genetic variants. Ninety-two 6- to 19-year-old individuals recruited through the University of Pittsburgh Dental Registry and DNA Repository project that had oral microbiome and genotyping of 44 single nucleotide polymorphism (SNP) data available were studied. Over-representation of alleles between individuals with or without particular microorganisms was determined using chi-square or Fisher's exact tests. Alpha of 0.001, to account for multiple testing (0.05/44), was considered statistically significant. Associations were found between Candida albicans and enamelin rs3796704 (p = 0.0006), and Staphylococcus epidermidis and tuftelin rs3828054 (p = 0.001). Microbiota and their metabolites might predispose oral disease when interacting with the host genetic variation and future studies should address their causal roles in oral disease.

Dynamic regulation of P-TEFb by 7SK snRNP is integral to the DNA damage response to regulate chemotherapy sensitivity

Testicular germ cell tumors and closely related embryonal stem cells are exquisitely sensitive to cisplatin, a feature thought to be linked to their pluripotent state and p53 status. It remains unclear whether and how cellular state is coordinated with p53 to confer cisplatin sensitivity. Here, we report that positive transcription elongation factor b (P-TEFb) determines cell fate upon DNA damage. We find that cisplatin rapidly activates P-TEFb by releasing it from inhibitory 7SK small nuclear ribonucleoprotein complex. P-TEFb directly phosphorylates pluripotency factor estrogen-related receptor beta (ESRRB), and induces its proteasomal degradation to enhance pro-survival glycolysis. On the other hand, P-TEFb is required for the transcription of a substantial portion of p53 target genes, triggering cell death during prolonged cisplatin treatment. These results reveal previously underappreciated roles of P-TEFb to coordinate the DNA damage response. We discuss the implications for using P-TEFb inhibitors to treat cancer and ameliorate cisplatin-induced ototoxicity.

•

P-TEFb regulates pro-survival and pro-death pathways during DNA damage response

•

P-TEFb promotes ESRRB proteasomal degradation to enhance pro-survival glycolysis

•

P-TEFb induces a substantial portion of p53 target genes to trigger cell death

•

Chemical inhibitors of P-TEFb blocks cisplatin- or UV-induced cell death

Relationship Between Dental Caries and Erosive Tooth Wear in Adolescents

Background

Our aim was to investigate the relationship between caries experience and erosive tooth wear of adolescents.

Methods

We compared the Decayed, Missing, and Filled Teeth (dmft/DMFT) data of 795 adolescents to their erosive tooth wear scores using diet as a covariate and determined if dental caries and erosive tooth wear scores are associated using linear regression analysis. Diet data and oral hygiene habits were collected using self-reported surveys and erosive tooth wear scores were previously collected. We also compared patients' genotypes and phenotypes and looked for an association between erosive tooth wear experience and different single nucleotide polymorphisms (SNPs). A Bonferroni correction was implemented to correct multiple comparisons. Two-group comparisons were made depending on the phenotype definitions implemented, and both chi-square and linear regression analyses were used to test association between genetic variants and caries definitions. All covariates were included in each model.

Results

For four SNPs (rs17159702, rs10246939, rs1800972, and rs1676303), there was an association between a spike in caries experience of DMFT 4 or more between two time points and increased frequency of fruit juice intake. A fifth SNP rs2860216 was shown to be a protective factor toward a spike in caries when coupled with more frequently eating yogurt. We did not find significant associations between our dental caries phenotypes or our demographic data and erosive tooth wear status in our linear regression.

Conclusions

Dental caries and erosive tooth wear are two diseases that differ in mechanism and heritability.

Biomarkers for Lifetime Caries-Free Status

The purpose of this study was to address the hypothesis that extreme outcomes of dental caries, such as edentulism or prematurely losing permanent teeth are associated with genetic variation in enamel-formation genes. After scanning 6206 individuals, samples of 330 were selected for this study. Tested phenotypes included patients who were edentulous by age 30, patients with missing first molars by age 30, patients with missing second molars by age 30, and caries-free patients. Fourteen single nucleotide polymorphisms were genotyped by TaqMan chemistry. The analyses of each phenotype were performed using the software PLINK with an alpha of 0.05. Nominal associations were found between rs12640848 in enamelin (p = 0.05), rs1784418 in matrix metallopeptidase 20 (p = 0.02), and rs5997096 in the tuftelin interacting protein 11 and being caries-free at the age of 60. When combining patients that were missing both first mandibular molars and missing both second mandibular molars, no associations were found. Matrix metallopeptidase 20, and tuftelin interacting protein 11 also showed trends for association with being caries-free. Genetic variation in TFIP11, MMP20, and ENAM may have a protective effect increasing the chances of individuals preserving their teeth caries-free over a lifetime.

Calcium and Phosphorus Levels in Saliva are Influenced by Genetic Polymorphisms in Estrogen Receptor Alpha and Microrna17

Homeostasis between salivary calcium and phosphorus is important for maintaining oral health. The aim of this study was to evaluate if polymorphisms in ESR1 (Estrogen Receptor Alpha), ESR2 (Estrogen Receptor Beta) and miRNA17 (microRNA17) are associated with calcium and phosphorus levels in saliva. Saliva from 276 12-year-old children were collected by masticatory stimulation and calcium and phosphorus levels were determined by Mass Spectrometry. Genomic DNA was extracted from remaining saliva and genetic polymorphisms in ESR1 (rs12154178, rs1884051, rs9340799 and rs2234693), in ESR2 (rs4986938 and rs1256049) and in miRNA17 (rs4284505) were genotyped using TaqMan chemistry and a real-time PCR equipment. Statistical differences in genotype and allele distributions between 'low' and 'high' calcium and phosphorus levels were determined using chi-square or Fisher´s exact tests. The analysis was also adjusted by sex (alpha of 5%). ESR1 rs9340799 had the less common genotype associated with higher calcium levels (p=0.03). The less common allele of ESR1 rs1884051 was associated with lower phosphorus levels (p=0.005) and there was an excess of heterozygotes for miRNA17 rs4284505 among individuals with lower calcium levels (p=0.002), both adjusted by sex. This study provides evidence that genetic polymorphisms in ESR1 and miRNA17 are involved in determining salivary calcium and phosphorus levels.

Genetic polymorphisms influence shear bond resistance of orthodontic brackets

OBJECTIVES

The purpose of this study was to determine if shear bond resistance of orthodontic brackets bonded to enamel is associated with genes implicated in the enamel mineralization process.

METHODS

Ninety-two permanent, caries-free premolars extracted for orthodontic purposes and their associated saliva samples were obtained. Eighteen single nucleotide polymorphisms (SNPs) were studied for association with shear bond resistance. The genes of interest in this study were those previously associated with dental caries by our group. All tooth samples were bonded on the buccal surface with metallic lower lateral brackets, and then subjected to physical debonding. The force required to debond the bracket was recorded in Newtons (N) and converted to a shear bond resistance value in Megapascals (N/mm²). The data were analyzed for statistical significance as compared with the mean shear bond resistance value via PLINK whole genome analysis software.

RESULTS

Associations were found between the SNPs for tuftelin (rs7526319, P = 0.004) and amelogenin (rs17878486, P = 0.04) and a higher shear bond resistance.

CONCLUSION

The collected data support the proposed hypothesis that genes involved in the mineralization process affect the bonding of orthodontic brackets, and such an association is of value for the field of orthodontics, particularly in evaluating the efficacy of enamel-resin bond strength for patients receiving treatment.

Understanding hormone and hormone therapies' impact on the auditory system

Hormones such as estrogen, progesterone, and aldosterone all demonstrate vital roles in sustaining auditory function through either the maintenance of cochlear neurons, up/down regulation of critical molecules (i.e., IGF-1, BDNF, etc.), or generation of the endocochlear potential. With disease and/or age, hormone expression begins to decline drastically, which ultimately affects cochlear structures and the integrity of cochlear cells. The following review explores the latest findings as well as realistic outcomes for hormone therapy treatment in the auditory system. This information could serve as a potential guide for patients considering hormone therapy as a medicinal choice to alleviate the signs of onset of presbycusis-age-related hearing loss. Additional scientific investigations could also be carried out to further enhance recent findings.

Measuring the Microscopic Structures of Human Dental Enamel Can Predict Caries Experience

OBJECTIVES

The hierarchical structure of enamel gives insight on the properties of enamel and can influence its strength and ultimately caries experience. Currently, past caries experience is quantified using the decayed, missing, filled teeth/decayed, missing, filled surface (DMFT/DMFS for permanent teeth; dmft/dmfs for primary teeth), or international caries detection and assessment system (ICDAS) scores. By analyzing the structure of enamel, a new measurement can be utilized clinically to predict susceptibility to future caries experience based on a patient's individual's biomarkers. The purpose of this study was to test the hypothesis that number of prisms by square millimeter in enamel and average gap distance between prisms and interprismatic areas, influence caries experience through genetic variation of the genes involved in enamel formation.

MATERIALS AND METHODS

Scanning electron microscopy (SEM) images of enamel from primary teeth were used to measure (i) number of prisms by square millimeter and interprismatic spaces, (ii) prism density, and (iii) gap distances between prisms in the enamel samples. The measurements were tested to explore a genetic association with variants of selected genes and correlations with caries experience based on the individual's DMFT+ dmft score and enamel microhardness at baseline, after an artificial lesion was created and after the artificial lesion was treated with fluoride.

RESULTS

Associations were found between variants of genes including ameloblastin, amelogenin, enamelin, tuftelin, tuftelin interactive protein 11, beta defensin 1, matrix metallopeptidase 20 and enamel structure variables measured (number of prisms by square millimeter in enamel and average gap distance between prisms and interprismatic areas). Significant correlations were found between caries experience and microhardness and enamel structure. Negative correlations were found between number of prisms by square millimeter and high caries experience (r value= -0.71), gap distance between prisms and the enamel microhardness after an artificial lesion was created (r value= -0.70), and gap distance between prisms and the enamel microhardness after an artificial lesion was created and then treated with fluoride (r value= -0.81). There was a positive correlation between number of prisms by square millimeter and prism density of the enamel (r value = 0.82).

CONCLUSIONS

Our data support that genetic variation may impact enamel formation, and therefore influence susceptibility to dental caries and future caries experience.

CLINICAL RELEVANCE

The evaluation of enamel structure that may impact caries experience allows for hypothesizing that the identification of individuals at higher risk for dental caries and implementation of personalized preventative treatments may one day become a reality.

Sex-specific differences in the salivary microbiome of caries-active children

Background and Objectives: Dental caries is a chronic disease affecting young children and has multi-factorial risk factors. The purpose of this work was to identify sex-specific differences in the salivary microbiota within caries-active children. Design: Saliva specimens were collected from 85 children (boys: 41; girls: 44) between the ages of 2-12 years. Salivary microbial DNA was subjected to PCR amplification using V3-V4 16S rDNA-specific primers and next-generation sequencing. Results: Significant sex differences in salivary microbiota were found between caries-active boys versus caries-active girls. Neisseria flavescens, Rothia aeria, and Haemophilus pittmaniae were found at significantly higher levels in caries-active boys. In contrast, Lactococcus lactis, Selenomonas species HOT 126, Actinobaculum species HOT 183, Veillonella parvula, and Alloprevotella species HOT 473 were found at significantly higher levels in caries-active girls. Conclusion: We have found the acid-generating, cariogenic Lactococcus lactis to be much more abundant in caries-active girls than caries-active boys, indicating that this microorganism may play a more significant role in shaping the cariogenic microbiome in girls. In addition, in caries-active girls, Alloprevotella species HOT 473 was the only species that exhibited both significant sex differences (4.4-fold difference; p=0.0003) as well as high abundance in numbers (1.85% of the total microbial population).

Excess of Rare Missense Variants in Hearing Loss Genes in Sporadic Meniere Disease

Meniere's disease (MD) is a clinical spectrum of rare disorders characterized by vertigo attacks, associated with sensorineural hearing loss (SNHL) and tinnitus involving low to medium frequencies. Although it shows familial aggregation with incomplete phenotypic forms and variable expressivity, most cases are considered sporadic. The aim of this study was to investigate the burden for rare variation in SNHL genes in patients with sporadic MD. We conducted a targeted-sequencing study including SNHL and familial MD genes in 890 MD patients to compare the frequency of rare variants in cases using three independent public datasets as controls. Patients with sporadic MD showed a significant enrichment of missense variants in SNHL genes that was not found in the controls. The list of genes includes GJB2, USH1G, SLC26A4, ESRRB, and CLDN14. A rare synonymous variant with unknown significance was found in the MARVELD2 gene in several unrelated patients with MD. There is a burden of rare variation in certain SNHL genes in sporadic MD. Furthermore, the interaction of common and rare variants in SNHL genes may have an additive effect on MD phenotype. This study will contribute to design a gene panel for the genetic diagnosis of MD.

A Comparative Study to Evaluate the Risk Factors for Medium-Sized Rotator Cuff Tear in Patients Younger Than 50 Years of Age

PURPOSE

The purpose of this study was to evaluate preoperative and intraoperative factors associated with rotator cuff tears (RCTs) among patients younger than 50 years and to compare arthroscopic rotator cuff repair (RCR) results in patients younger than 50 years (group A) and patients older than 70 years (group B). We also analyzed the results after arthroscopic RCR in these 2 age groups.

METHODS

Data were collected from 56 patients allocated to group A and 55 patients allocated to group B who had medium-sized RCTs and had undergone arthroscopic RCR between January 2006 and August 2015. Preoperative variables included demographic data, radiologic data, and surgical procedure. We evaluated fatty degeneration on preoperative magnetic resonance imaging (MRI) and intraoperative variables, including concomitant subscapularis repair, as well as repair technique. Pain visual analog scale, functional visual analog scale, American Shoulder and Elbow Surgeons, and Constant scores were documented to compare functional results in each age group. Postoperative MRI scans were conducted to evaluate the retear rate after RCR after a mean postoperative duration of 5.4 months (range, 2-48 months).

RESULTS

Multivariate regression analysis showed acute-on-chronic injury and a history of hypertension were independent factors for differentiation of the groups. Stepwise regression analysis found sex, hypertension, and fatty infiltration of the supraspinatus and infraspinatus to be comparable factors for each group. All patients showed improved results after arthroscopic RCR, but there was no difference between the 2 groups in functional outcomes. However, cuff retears on postoperative MRI scans were found in only 3.9% of the patients in group A versus 16% of the patients in group B.

CONCLUSIONS

The results of this study showed that sex, acute-on-chronic injury, and preoperative fatty infiltration of the rotator cuff were significant factors affecting medium-sized RCTs in patients younger than 50 years. In addition, there were no significant differences in functional outcomes after arthroscopic RCR in both groups at 2 years, but postoperative MRI showed a lower retear rate in group A.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Host genetics role in the pathogenesis of periodontal disease and caries

BACKGROUND

This study aimed to produce the latest summary of the evidence for association of host genetic variants contributing to both periodontal diseases and caries.

MATERIALS AND METHODS

Two systematic searches of the literature were conducted in Ovid Medline, Embase, LILACS and Cochrane Library for large candidate gene studies (CGS), systematic reviews and genome-wide association studies reporting data on host genetic variants and presence of periodontal disease and caries.

RESULTS

A total of 124 studies were included in the review (59 for the periodontitis outcome and 65 for the caries outcome), from an initial search of 15,487 titles. Gene variants associated with periodontitis were categorized based on strength of evidence and then compared with gene variants associated with caries. Several gene variants showed moderate to strong evidence of association with periodontitis, although none of them had also been associated with the caries trait.

CONCLUSIONS

Despite some potential aetiopathogenic similarities between periodontitis and caries, no genetic variants to date have clearly been associated with both diseases. Further studies or comparisons across studies with large sample size and clear phenotype definition could shed light into possible shared genetic risk factors for caries and periodontitis.

Redefining the Phenotype of Dental Caries

Dental caries is a multifactorial infectious disease and a major public health problem estimated to affect 60-90% of school children as well as a vast number of adults. The aim of this work was to define patterns of progression of the disease based on longitudinal data in contrast to using a cross-sectional assessment. dmft/DMFT scores were collected at ages 5, 12, 14, 16, 17, and 18 from 876 individuals. We tested our newly defined phenotypes for association with genetic variants in genes shown to be associated with caries. We generated genotyping data using Taqman chemistry in markers of genes involved in processes such as enamel formation and salivary contributions. Kallikrein 4 (KLK4) was found to show a significant association with the created phenotypes (p = 0.0008 in a recessive model for low caries experience in the primary dentition vs. high caries experience in the primary dentition, and p = 0.0004 in a recessive model for caries free primary dentition vs. high caries experience in the primary dentition).

Extensive Supporting Cell Proliferation and Mitotic Hair Cell Generation by In Vivo Genetic Reprogramming in the Neonatal Mouse Cochlea

The generation of hair cells (HCs) from the differentiation of proliferating supporting cells (SCs) appears to be an ideal approach for replacing lost HCs in the cochlea and is promising for restoring hearing after damage to the organ of Corti. We show here that extensive proliferation of SCs followed by mitotic HC generation is achieved through a genetic reprogramming process involving the activation of β-catenin to upregulate Wnt signaling, the deletion of Notch1 to downregulate Notch signaling, and the overexpression of Atoh1 in Sox2(+) SCs in neonatal mouse cochleae. We used RNA sequencing to compare the transcripts of the cochleae from control mice and from mice with β-catenin activation, Notch1 deletion, and β-catenin activation combined with Notch1 deletion in Sox2(+) SCs. We identified the genes involved in the proliferation and transdifferentiation process that are either controlled by individual signaling pathways or by the combination of Wnt and Notch signaling. Moreover, the proliferation of SCs induced by Notch1 deletion disappears after deleting β-catenin in Notch1 knock-out Sox2(+) cells, which further demonstrates that Notch signaling is an upstream and negative regulator of Wnt signaling.

SIGNIFICANCE STATEMENT

We show here that the extensive proliferation of supporting cells (SCs) and the subsequent mitotic hair cell (HC) generation is achieved through a genetic reprogramming process involving activation of β-catenin to upregulate Wnt signaling, deletion of Notch1 to downregulate Notch signaling, and overexpression of Atoh1 in Sox2(+) SCs in neonatal mice cochleae. By comparing the transcripts of the cochleae among controls, β-catenin activation, Notch1 deletion, and β-catenin activation combined with Notch1 deletion group, we identified multiple genes involved in the proliferation and transdifferentiation process that are either controlled by individual signaling pathways or by the combination of Wnt and Notch signaling. This provides a better understanding of the mechanisms behind mitotic HC generation and might provide new approaches to stimulating mitotic HC regeneration.

Single Nucleotide Polymorphism in the Aetiology of Caries: Systematic Literature Review

Recent progress in the field of molecular biology and techniques of DNA sequence analysis allowed determining the meaning of hereditary factors of many common human diseases. Studies of genetic mechanisms in the aetiology of caries encompass, primarily, 4 main groups of genes responsible for (1) the development of enamel, (2) formation and composition of saliva, (3) immunological responses, and (4) carbohydrate metabolism. The aim of this study was to present current knowledge about the influence of single nucleotide polymorphism (SNP) genetic variants on the occurrence of dental caries. PubMed/Medline, Embase, and Cochrane Library databases were searched for papers on the influence of genetic factors connected with SNP on the occurrence of dental caries in children, teenagers, and adults. Thirty original papers written in English were included in this review. Study groups ranged from 30 to 13,000 subjects. SNPs were observed in 30 genes. Results of the majority of studies confirm the participation of hereditary factors in the aetiology of caries. Three genes, AMELX, AQP5, and ESRRB, have the most promising evidence based on multiple replications and data, supporting a role of these genes in caries. The review of the literature proves that SNP is linked with the aetiology of dental caries.

Genetic and familial predisposition to rotator cuff disease: a systematic review

BACKGROUND

Rotator cuff disease is a common disorder leading to shoulder pain and loss of function. Its etiology in atraumatic cases is uncertain and is likely to extend beyond repetitive microtrauma or overuse. Our objective was to determine whether there is a genetic or familial predisposition to rotator cuff disease.

METHODS

A literature search of PubMed and Embase databases identified 251 citations. After review of the titles, abstracts, and full articles, 7 met our inclusion and exclusion criteria.

RESULTS

Four studies assessed familial predisposition to rotator cuff disease. One of these demonstrated that siblings of an individual with a rotator cuff tear were more likely to develop a full-thickness tear and more likely to be symptomatic. A 5-year follow-up showed that the relative risks were increased for the siblings to have a full-thickness tear, for a tear to progress in size, and for being symptomatic. Another study demonstrated that a significantly higher number of individuals with tears had family members with a history of tears or surgery than those without tears did. The other 3 studies investigated whether a genetic predisposition to rotator cuff disease exists and found significant association of haplotypes in DEFB1, FGFR1, FGF3, ESRRB, and FGF10 and 2 single-nucleotide polymorphisms within SAP30BP and SASH1.

CONCLUSION

Prior studies provide preliminary evidence for genetic and familial predisposition to rotator cuff disease. However, there is a lack of large genome-wide studies that can provide more definitive information and guide early detection of individuals at risk, prophylactic rehabilitation, and potential gene therapies and regenerative medicine interventions.

Genes Involved in the Enamel Development Are Associated with Calcium and Phosphorus Level in Saliva

Saliva components play a crucial role in the integrity of the dental enamel and in caries susceptibility. The saliva characteristics are controlled by many factors, including genetic factors. Therefore, this study aimed to evaluate the association between the genetic variations in genes expressed in enamel development with calcium and phosphorus levels in saliva. We collected 276 unrelated 12-year-old children from private and public schools. Saliva was collected for DNA extraction from oral cells and for measurement of calcium and phosphorus. Inductively coupled plasma-mass spectrometry determined calcium and phosphorus levels in whole saliva. Fifteen genetic variations in 9 genes were analyzed. The genotype was determined by real-time polymerase chain reactions. Data were analyzed using Plink with an alpha of 5%. Genetic variations in AMELX, AMNB and ESRRB were associated with the calcium level in saliva (p < 0.05). A borderline association was observed in ENAM allele distribution shown with phosphate level in saliva (p = 0.049). In conclusion, our results are the first to report that genetic variations contribute to calcium and phosphorus levels in saliva.

Genetic disorders of nuclear receptors

Following the first isolation of nuclear receptor (NR) genes, genetic disorders caused by NR gene mutations were initially discovered by a candidate gene approach based on their known roles in endocrine pathways and physiologic processes. Subsequently, the identification of disorders has been informed by phenotypes associated with gene disruption in animal models or by genetic linkage studies. More recently, whole exome sequencing has associated pathogenic genetic variants with unexpected, often multisystem, human phenotypes. To date, defects in 20 of 48 human NR genes have been associated with human disorders, with different mutations mediating phenotypes of varying severity or several distinct conditions being associated with different changes in the same gene. Studies of individuals with deleterious genetic variants can elucidate novel roles of human NRs, validating them as targets for drug development or providing new insights into structure-function relationships. Importantly, human genetic discoveries enable definitive disease diagnosis and can provide opportunities to therapeutically manage affected individuals. Here we review germline changes in human NR genes associated with "monogenic" conditions, including a discussion of the structural basis of mutations that cause distinctive changes in NR function and the molecular mechanisms mediating pathogenesis.

In Vitro Acid-Mediated Initial Dental Enamel Loss Is Associated with Genetic Variants Previously Linked to Caries Experience

We have previously shown that AQP5 and BTF3 genetic variation and expression in whole saliva are associated with caries experience suggesting that these genes may have a functional role in protecting against caries. To further explore these results, we tested ex vivo if variants in these genes are associated with subclinical dental enamel mineral loss. DNA and enamel samples were obtained from 53 individuals. Enamel samples were analyzed for Knoop hardness of sound enamel, integrated mineral loss after subclinical carious lesion creation, and change in integrated mineral loss after remineralization. DNA samples were genotyped for single nucleotide polymorphisms using TaqMan chemistry. Chi-square and Fisher's exact tests were used to compare individuals above and below the mean sound enamel microhardness of the cohort with alpha of 0.05. The A allele of BTF3 rs6862039 appears to be associated with harder enamel at baseline (p = 0.09), enamel more resistant to demineralization (p = 0.01), and enamel that more efficiently regain mineral and remineralize (p = 0.04). Similarly, the G allele of AQP5 marker rs3759129 and A allele of AQP5 marker rs296763 are associated with enamel more resistant to demineralization (p = 0.03 and 0.05, respectively). AQP5 and BTF3 genetic variations influence the initial subclinical stages of caries lesion formation in the subsurface of enamel.

A Polymorphism in the MTRR Gene Is Associated with Early Childhood Caries and Underweight

Polymorphisms in genes encoding the enzymes involved in the metabolism of homocysteine, such as methionine synthase (MTR) and methionine synthase reductase (MTRR), play an important function in the metabolism of folic acid and vitamin B12. The present study aimed to evaluate the association of polymorphisms in genes MTR (rs1805087) and MTRR (rs1801394) with susceptibility of early childhood caries (ECC) and with body mass index alterations. A cross-sectional study was performed in 488 children aged from 2 to 6 years from 25 public day care centers in Rio de Janeiro, Brazil. Demographic data and oral health habits were obtained through a questionnaire. Anthropometric measurements and caries experience data were collected by 2 examiners (κ = 0.80). Genotyping of the selected polymorphisms was carried out by TaqMan real-time PCR using genomic DNA extracted from buccal cells. Allele and genotype frequencies were compared between groups with and without disease. The t test, χ2 test, odds ratio, Pearson correlation tests, and logistic regression analysis were used (p ≤ 0.05). The mean white spot lesion score was 1.18 (±2.57) in normal weight children and 2.50 (±3.87) in underweight children (p = 0.05). For MTRR polymorphisms, significant differences were observed for allele and genotype frequency distributions between caries-free and caries-affected children (p = 0.03 and 0.04 for allele and genotype frequencies, respectively) and in the genotype frequencies between normal weight and underweight children (p = 0.04). Our results suggest an association between underweight and ECC; in addition it is suggested that MTRR is a common genetic risk factor for ECC and underweight.

Estrogen-related receptor β (ERRβ) - renaissance receptor or receptor renaissance?

Estrogen-related receptors (ERRs) are founding members of the orphan nuclear receptor (ONR) subgroup of the nuclear receptor superfamily. Twenty-seven years of study have yet to identify cognate ligands for the ERRs, though they have firmly placed ERRα and ERRγ at the intersection of cellular metabolism and oncogenesis. The pace of discovery for novel functions of ERRβ, however, has until recently been somewhat slower than that of its family members. ERRβ has also been largely ignored in summaries and perspectives of the ONR literature. Here, we provide an overview of established and emerging knowledge of ERRβ in mouse, man, and other species, highlighting unique aspects of ERRβ biology that set it apart from the other two estrogen-related receptors, with a focus on the impact of alternative splicing on the structure and function of this receptor.