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Objective: To investigate the association between feeding practices (exclusive breastfeeding, exclusive bottle-feeding, and mixed) with early childhood caries (ECC) and the association between the prevalence of oral Rothia, at the species and genus level, with ECC. Methods: A total of 438 children (178 caries-free, 260 with ECC) were included in this case-control study. A comprehensive questionnaire that included a section on feeding history, was completed by the parent or caregiver of each participant. Based on the feeding history responses, participants were classified as either exclusively breastfed, exclusively bottle-fed, or mixed (both bottle-fed and breastfed). A supragingival plaque sample was collected from each participant and then assessed with 16S rRNA sequencing for Rothia genus and species’ relative abundances. The association between feeding practices and Rothia prevalence with ECC, accounting for confounding variables, was analyzed using multivariable logistic regressions. Results: A low relative abundance of Rothia aeria was significantly associated with ECC (p<0.05), whereas there were no significant associations found between the relative abundance of Rothia dentocariosa or Rothia mucilaginosa with caries status (p>0.05). While the odds of association between a low relative abundance of Rothia (genus) and ECC was 1.63, this relationship failed to reach the threshold of significance (p=0.054). Feeding practices were not significantly associated with ECC after adjusting for confounding variables. However, bedtime bottle use, bedtime snacking, living in a rural/remote area, being an older age, the use of fluoridated toothpaste, and having less-educated guardians were significantly associated with ECC (p<0.05) Conclusions: Findings in this study suggest that low relative abundances of R. aeria and Rothia (genus) are associated with ECC. Feeding practices were not key risk factors for ECC in this sample, as other factors related to the social environme

The loss of effective therapeutic options due to the increase instances of antimicrobial resistant bacterial infections is of great concern to the World Health Organization (WHO). The WHO released a list to prioritize efforts in fighting this problem and placed carbapenem-resistant Acinetobacter baumannii as the top priority in need of development of new therapeutic options. A. baumannii is a Gram-negative opportunistic pathogen that can survive within clinical environments. A lot is known about the ability of this species to resist and tolerate the effects of antimicrobials. It possesses three efflux pumps of the resistance-nodulation-division (RND) efflux family, AdeAB(C), AdeFGH, and AdeIJK, that when overexpressed are responsible for reducing the susceptibility of A. baumannii to several antibiotic classes. These RND efflux pumps, and AdeFGH in particular, were the focus of my study. In this study I have investigated regulation and physiological function of AdeFGH, which is the least well studied RND efflux pump of the three. I have shown that AdeFGH expression has profound effects on the motility and biofilm formation of A. baumannii and that this is most likely due to increased efflux of acyl homoserine lactones. The effect of AdeFGH on motility and biofilm formation appears to be AdeL-independent. Interestingly, the overexpression of AdeL led to increased virulence in Galleria mellonella. I have discovered that the expression of adeFGH is induced by nitrosative stress and regulated by not only its cognate regulator, AdeL, but also by the global regulator, CsrA. I have investigated the role of CsrA in the physiology of A. baumannii via transcriptomics and phenotypic microarray. Additional investigations into AdeIJK showed it was crucial for A. baumannii virulence in G. mellonella and increased expression lead to increased tolerance to osmotic stress. All of this combined furthers our understanding of A. baumannii physiology and identifies several new potential

Background: The C1Q-tumor necrosis factor related protein (CTRP) family has functions in metabolism, immunity, and cancer. Among the CTRP family, CTRP8 remains the least well characterized in terms of function and receptors. In the brain tumor glioblastoma (GBM), CTRP8 impacts migration and treatment resistance through its receptor RXFP1. We investigate a new interaction between CTRP8 and the EGF-like protein Delta-like homolog 1 (DLK1). DLK1 is a well-known regulator of differentiation and is considered a marker of stemness in several cancers. In GBM, elevated DLK1 expression promotes migration, stemness and has been correlated with poor prognosis. There is interest in further understanding complex mechanisms of DLK1 in a cancer context. Methodology: A yeast-two hybrid (Y2H) screen and co-immunoprecipitation (co-IP) were used to characterize CTRP8-DLK1 interaction domains. The U251 cell line was used to assess stemness using tumor sphere formation and glioma stem cell (GSC) marker expression. In the same U251 model we investigate mechanisms responsive to CTRP8-DLK1 that regulate GSCs. Results: The Y2H identified DLK1 as a CTRP8 interaction partner. In co-IP CTRP8 binds full-size DLK1 and a truncated, soluble form of DLK1. DLK1 enhanced sphere formation and GSC marker expression in U251. The pro-stemness effect of DLK1 was counteracted by CTRP8, resulting in an overall reduction in stemness. Reduced stemness in cells expressing a cleavage-resistant DLK1 form revealed potential functions of DLK1 cleavage products as factors regulating the GSC population. In U251 cells expressing DLK1, CTRP8 treatment increased DLK1 intracellular domain (ICD) release and nuclear translocation. DLK1 ICD may act as a transcriptional co-factor revealing a new function for DLK1 ICD. Conclusions: This is the first study describing CTRP8 as a DLK1 ligand. Our findings reveal DLK1 as a promoter of glioma stemness, and CTRP8 as an antagonist. The CTRP8-DLK1 interaction may be part of a novel

Objective: To investigate the oral health-related quality of life (OHRQoL) of young children in a randomized clinical trial of silver diamine fluoride (SDF) with 5% fluoride varnish (FV) to manage early childhood caries (ECC). Methods: Children < 72 months of age with active dentinal caries lesions (ICDAS 5 or 6) in primary teeth received two applications of 38% SDF and 5% FV as part of a randomized clinical trial testing three different frequency regimes (1, 4 and 6 months apart). The early childhood oral health impact scale (ECOHIS) questionnaire was completed at each study visit. Statistical analyses included descriptive and parametric methods. A p-value ≤ 0.05 was statistically significant. Results: Eighty-two children (58.5% male) were recruited with a mean age of 44.3±14.2 months. Statistically significant improvement in total ECOHIS scores for all children was observed following treatment (baseline mean scores 4.64±4.74 vs. second visit score 3.26±4.36 vs. third visit score 3.25±3.77, p=0.006 and p=0.01, respectively). The following domains showed the most improvement with SDF treatment: parental distress, and family function. No statistically significant difference in ECOHIS scores were observed between the three frequency groups at baseline, second visit, and final visit (p=0.24, p=0.71 and 0.26) Conclusions: Children exhibited improved overall OHRQoL following two applications of 38% SDF and 5% FV, although there were no significant differences observed between the treatment groups. The results from our study demonstrate that SDF is a suitable non-restorative caries management option for children with ECC as it is associated with improved oral health related quality of life.

Objective: To investigate the effectiveness of silver diamine fluoride (SDF) to arrest early childhood caries (ECC) in very young children randomized to three different application frequency groups (regimens) Methods: Children with active dentinal carious lesions (ICDAS 5 or 6) in primary teeth without any signs of pulpal involvement were randomized into three different application frequency groups; 1, 4, or 6 months apart. Children underwent treatment with 38% SDF at baseline visit and again at a second visit. Treated lesions were assessed at the second and third visits to determine arrest success. Participants were considered completely successful (CS) if all treated lesions were arrested and incompletely successful (IS) if at least one lesion was not arrested. Statistical analyses included descriptive and bivariate analyses. A p value ≤ 0.05 was significant. Results: A total of 84 children with 486 carious lesions were recruited into the study with 28 children in each group. The overall proportion of completely successful treated children at visit 2 and final visit were 40% and 68% respectively. Results of McNemar’s test showed a significant increase in complete success from 40% at second visit to 68% at visit 3 (p-value <0.001) across all groups for 84 study participants. Within each group, significant improvement in complete success at child-level was also noted with p-values of 0.041,0.023 and 0.004 for Regimen 1, 2 and 3 respectively. Participants in one month group showed a change of complete success from 36% at second visit to 71% at third visit (p-value 0.004). No significant differences were noted between the groups at second visit and final visit (p >0.05) Conclusions: Findings in this study suggested that two applications of SDF at different frequencies showed similar frequency of successfully treated cases at the child level. No difference was noted in success rates comparing three groups either at second or third visit. Results from our study

Introduction: Silver diamine fluoride (SDF) is a simple and non-invasive agent to arrest caries in children. The purpose of this study is to investigate changes to the oral bacteriome and mycobiome in young children treated with SDF Methods: Plaque samples were collected from 45 children with early childhood caries (ECC). Frequency regimens of SDF were two applications 4 months apart (4M), two applications 6 months apart (6M), and two applications 1 month apart (1M). DNA was extracted and sent to Genome Quebec Innovation Center for library preparation and paired-end Illumina MiSeq PE300 sequencing of the V4 region of bacterial 16S rRNA and fungal ITS1 rRNA genes. Sequencing data was analyzed using QIIME2 2018.11. Results: A total of 195 carious lesions in 44 children were treated at baseline and followed over two subsequent study visits. The overall arrest rates were 77.69% at Visit 2 and 93.61% at Visit 3 respectively. Arrest rates were higher for all lesions after two applications of SDF. The alpha diversity and beta diversity analysis showed no significant differences in the supragingival bacteriome and mycobiome for all three regimens. Taxonomic assignment showed that Streptococcus, Corynebacterium and Actinomyces were the most abundant genera for Bacteria and Candida, Blumeria, and Malassezia were the most abundant genera for Fungi. Streptococcus mutans and Veillonella dispar both showed a decrease in relative abundance, but these changes were a trend and not found to be statistically significant. Candida albicans was highly abundant in all groups regardless of number of visits or regimens. The differential abundance analysis showed significant changes in both bacterial and fungal species, particularly Lactobacillus spp., Bifidobacterium spp. and Candida spp. Our study found a vast diversity of fungal species and differential abundance analysis suggested that SDF treatment may have an effect on the abundance of specific fungi. Conclusion: SDF was an effective m

Early childhood caries (ECC) and its more severe form S-ECC are prevalent diseases linked to various etiologic factors, including sex, microbiota, diet, and genetics. Recent studies have highlighted the role of inter-kingdom interactions involving fungi and cariogenic bacteria in the onset of dental caries. However, sex-specific and oral site-specific differences in the oral microbiome are poorly characterized. Evidence suggests that there is a plausible relationship between genetic variants in taste genes and enhanced ECC risk or protection. This has been attributed to the modulatory effect of bitter taste receptors on taste preferences and oral innate immune responses. Nevertheless, previous caries studies focused on select sweet and bitter taste receptors (T1Rs and T2Rs), with minimal or no attention to other taste signal transducing proteins such as free fatty acid receptors (FFARs), salt and sour ion channels (ENaCs and OTOP1), and carbonic anhydrases (CAs). Therefore, this study investigated whether variants in multiple taste genes play a role in S-ECC and the oral microbiome. The first part of the thesis focuses on characterizing the oral microbiome, identifying sex-specific and site-specific bacterial and fungal species that are associated with S-ECC. The second part evaluates the association of taste genetic variants with S-ECC and the dental plaque microbial composition. The third part investigates the role of seven genes, involved in downstream taste signaling, in S-ECC and dental biofilm composition. These studies demonstrate that sex- and site-specific differences in the oral microbiome exist. A significant difference in the abundance of Neisseria was observed between males and females with S-ECC. Streptococcus mutans, Candida albicans, and Candida dubliniensis, among others, were enriched in the dental plaque, compared to oral swabs, of children with S-ECC. Also, genetic variants in genes encoding proteins involved in taste sensations (SCNN1D, CA6, TAS

The fundamental framework of steroidogenesis across steroidogenic cells is similar, especially the initial mitochondrial steps involving cholesterol translocation across outer mitochondrial membrane (OMM) by the START domain containing proteins (e.g., StAR) and subsequent conversion to pregnenolone by the enzyme P450scc in the inner mitochondrial membrane (IMM). Thus, cholesterol and mitochondria are essential and highly interconnected in steroidogenesis. However, our understanding of this conserved process in steroidogenesis remains limited. Particularly, the transport of cholesterol from the OMM to the IMM. Moreover, growing evidence suggest an important role of autophagy/lipophagy and mitochondrial dynamics in regulating steroidogenic cholesterol homeostasis. However, a potential role the intracellular cholesterol pool in itself in the regulation steroidogenic events remains unexplored. I investigated an unexpected testicular phenotype of two transgenic mouse models and found that the male transgenic mice that expressed a mutant form of a mitochondrial protein prohibitin-1 (PHB1Tyr114Phe) from the Fabp-4 gene promoter displayed smaller testes, higher testosterone levels and lower gonadotropin levels as compared with age matched PHB-1 overexpressing and wild-type mice. Additionally, I found StAR and P450scc as interacting partners of PHB1 in Leydig cell mitochondria. Further analysis of testis and Leydig cells from the transgenic mice revealed that PHB1 plays a regulatory role in coordinating cell signaling, cholesterol homeostasis, and mitochondrial biology pertaining to steroidogenesis. Moreover, I tested the hypothesis that intracellular cholesterol pool in steroidogenic cells plays a role in regulating cell-intrinsic factors and events pertaining steroidogenesis. I found that the depletion of intracellular cholesterol pool in steroidogenic cells (i.e., MA-10, Y-1 and BeWo cells) induces autophagy, affects mitochondrial dynamics, and upregulates steroidogenic f

Introduction: Early childhood caries (ECC) is a widespread, multifactorial disease. Dental decay is a result of low-pH demineralization caused by acidogenic bacteria living in oral biofilms. Nutrition is a key determinant of ECC, as these bacteria require fermentable carbohydrates to grow. Veillonella are important bacteria that facilitate the activity of acidogenic bacteria by removing excess lactate products. A majority of oral microbiome studies focus on the importance of well-known cariogenic bacteria, such as Streptococcus mutans, while few studies have characterized Veillonella in ECC. The purpose of this study was to gain a greater understanding of the relationship between nutrition, oral Veillonella, and ECC. Methods: A case-control study design was used. The nutritional profiles of 158 children (75 caries-free, 83 with ECC) from Manitoba were determined via NutriSTEP (Nutrition Screening Tool for Every Preschooler and Toddler). Veillonella species were assessed using relative abundance data from 16S rRNA sequencing of dental plaque samples. A multivariable logistic regression model was used to estimate the association of ECC with NutriSTEP scores and relative abundance of Veillonella. Results: Caries-affected children tended to be older, established residents, Indigenous, live in rural or remote areas, and have less-educated parents (p ≤ 0.05). Children with ECC had higher total NutriSTEP scores (23.7 ± 6.8) than children without ECC (21.1 ± 6.6; p ≤ 0.05). Relative abundance data revealed significantly higher levels of Veillonella dispar, Streptococcus mutans, and Streptococcus salivarius in caries-affected children (p ≤ 0.05). Children with a high abundance of Veillonella parvula (OR = 2.33; 95% CI: 1.10, 4.91) and greater nutritional risk/NutriSTEP scores (OR = 1.08; 95% CI: 1.02, 1.14) were more likely to experience ECC than children with insignificant levels of the bacteria and lower nutritional risk/NutriSTEP scores. Conclusions: Our findings reflect