Multiple Hypothesis Testing for Experimental Gingivitis Based on Wilcoxon Signed Rank Statistics

Mutations in the cell-binding motif of lam-3/laminin α reveal hypercontraction behavior and defective sensitivity to levamisole in Caenorhabditis elegans

The amino acid sequence Arg-Gly-Asp (RGD) is a cell-binding motif for extracellular matrix proteins. Initially found in fibronectin, the RGD motif is also found in LAM-3/laminin α chain in C. elegans. Laminin, a heterotrimeric glycoprotein, is a significant component of the basement membrane. Mutations in laminin subunits disrupt the extracellular matrix hence inhibit cell adhesion. This study aims to characterize the function of the RGD motif in lam-3/laminin α. Two mutations, lam-3 RGE and lam-3 ΔRGD, were generated. Our analysis of the mutants revealed that the RGD motif is involved in the motility of animals, suggesting that the cell-laminin interaction plays a role in regulating body contraction.

Is Fluorescence Technology a Promising Tool for Detecting Infected Dentin in Deep Carious Lesions?

The purpose of this study was to determine if the degree of fluorescence detected by fluorescence-aided caries excavation (FACE) correlates with dentin bacterial microbiome diversity, as assessed by 16S rRNA gene amplicon sequencing, and with traditional tactile dentin caries assessment. Unidentified human teeth were obtained from a dental facility. The included teeth had a carious lesion two-thirds into the dentin, verified by radiography, and were red-fluorescing (RF) using FACE technology (SIROInspect; Sirona, Bensheim, Germany). Two independent examiners performed visual/tactile assessment of the lesions. RF sites were sampled with a sterile spoon excavator and dentin characteristics were evaluated. Once RF dentin was removed, a second sample of pink-fluorescing (PF) dentin was obtained. After excavation with a sterile round bur to nonfluorescing (NF) dentin, a third sample was collected with a slow-speed round bur. The samples were processed at the UNC (University of North Carolina at Chapel Hill) Microbiome Core Facility. Out of 134 extracted teeth collected, 21 fit the inclusion criteria, yielding 61 dentin samples. RF samples had the highest number of observed operational taxonomic units (n = 154), followed by PF (n = 109) and NF (n = 100). RF carious dentin was primarily "soft," and NF dentin was assessed as "hard" 100% of the time by both examiners (rank correlation χ2: p < 0.001). However, approximately one-third of the tactile assessments of hard dentin still displayed some fluorescence, either pink or red. We concluded that the sampled fluorescing (RF and PF) and NF carious dentin layers displayed diverse bacterial taxa, and tactile assessments of soft, leathery, and hard corresponded with RF, PF, and NF.

Expression of pro-apoptotic markers is increased along the osteochondral junction in naturally occurring osteochondrosis

Osteochondrosis (OC) is a naturally occurring disease of the articular-epiphyseal cartilage and subchondral bone layers, leading to pain and decreased mobility. The objective of this study was to characterize gene and protein expression of apoptotic markers in chondrocytes surrounding cartilage canals and along the osteochondral junction of osteochondrosis (OC)-affected and normal cartilage, using naturally occurring disease in horses. Paraffin-embedded osteochondral samples (6 OC, 8 normal controls) and cDNA from chondrocytes captured with laser capture microdissection (4 OC, 6 normal controls) were obtained from the lateral trochlear ridge of femoropatellar joints in 14 immature horses (1–6 months of age). Equine-specific caspase-3, caspase-8, caspase-10, Fas, Bcl-2, BAG-1, TNFα, cytochrome C, thymosin-β10, and 18S mRNA expression levels were evaluated by two-step real-time quantitative PCR. Percentage of cell death was determined using the TUNEL method. Protein expression of caspase-10, Fas, cytochrome C, and thymosin-β10 was determined following immunohistochemistry. Statistical analysis was performed using the Wilcoxon rank sum test or two-sample t-test (p < 0.05). In OC samples, there was significantly increased gene expression of caspase-10, Fas, cytochrome C, and thymosin-β10 in chondrocytes along the osteochondral junction and increased Fas gene expression in chondrocytes adjacent to cartilage canals, compared to controls. In OC samples, higher matrix Fas and cytochrome C protein expression, lower mitochondrial cytochrome C protein expression, and a trend for higher cytoplasmic caspase-10 protein expression were found. Collectively, these results suggest that both extrinsic and intrinsic apoptotic pathways are activated in OC cartilage. Increased apoptosis of osteochondral junction chondrocytes may play a role in OC, based on increased gene expression of several pro-apoptotic markers in this location.

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Pro-apoptotic marker gene expression increased in osteochondrosis cartilage

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Extrinsic and intrinsic apoptotic pathways activated along osteochondral junction

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Higher caspase-10, Fas, cytochrome C, and thymosin-β10 gene expression

Wnt/β-catenin signaling of cartilage canal and osteochondral junction chondrocytes and full thickness cartilage in early equine osteochondrosis

The objective of this study was to elucidate gene and protein expression of Wnt signaling molecules in chondrocytes of foals having early osteochondrosis (OC) versus normal controls. The hypothesis was that increased expression of components of Wnt signaling pathway in osteochondral junction (OCJ) and cartilage canal (CC) chondrocytes would be found in early OC when compared to controls. Paraffin-embedded osteochondral samples (7 OC, 8 normal) and cDNA from whole cartilage (7 OC, 10 normal) and chondrocytes surrounding cartilage canals and osteochondral junctions captured with laser capture microdissection (4 OC, 6 normal) were obtained from femoropatellar joints of 17 immature horses. Equine-specific Wnt signaling molecule mRNA expression levels were evaluated by two-step real-time qPCR. Spatial tissue protein expression of β-catenin, Wnt-11, Wnt-4, and Dkk-1 was determined by immunohistochemistry. There was significantly decreased Wnt-11 and increased β-catenin, Wnt-5b, Dkk-1, Lrp6, Wif-1, Axin1, and SC-PEP gene expression in early OC cartilage canal chondrocytes compared to controls. There was also significantly increased β-catenin gene expression in early OC osteochondral junction chondrocytes compared to controls. Based on this study, abundant gene expression differences in OC chondrocytes surrounding cartilage canals suggest pathways associated with catabolism and inhibition of chondrocyte maturation are targeted in early OC pathogenesis.

A Potential Biofilm Metabolite Signature for Caries Activity - A Pilot Clinical Study

BACKGROUND

This study's aim was to compare the dental biofilm metabolite-profile of caries-active (N=11) or caries-free (N=4) children by gas chromatography-mass spectrometry (GC/MS) analyses.

METHODS

Samples collected after overnight fasting, with or without a previous glucose rinse, were combined for each child based on the caries status of the site, re-suspended in ethanol and analyzed by GC/MS.

RESULTS

Biofilm from caries-active sites exhibited a different chromatographic profile compared to caries-free sites. Qualitative and quantitative analysis suggested a special cluster of branched alcohols and esters present at substantially higher intensity in biofilms of caries-active sites.

CONCLUSIONS

This pilot study indicates that there are metabolites present in the biofilm which have the potential to provide a characteristic metabolomics signature for caries activity.

Age-related differential gene and protein expression in postnatal cartilage canal and osteochondral junction chondrocytes

Wnt/β-catenin, Indian hedgehog (Ihh)/Parathyroid-related peptide (PTHrP) and retinoid signaling pathways regulate cartilage differentiation, growth, and function during development and play a key role in endochondral ossification. The objective of this study was to elucidate the gene and protein expression of signaling molecules of these regulatory pathways in chondrocytes surrounding cartilage canals and the osteochondral junction during neonatal and pre-adolescent development. This study revealed cell-specific and age-related differences in gene and protein expression of signaling molecules of these regulatory pathways. A trend for higher gene expression of PTHrP along the cartilage canals and Ihh along the osteochondral junction suggests the presence of paracrine feedback in articular-epiphyseal cartilage. Differential expression of canonical (β-catenin, Wnt-4, Lrp4, Lrp6) and noncanonical Wnt signaling (Wnt-5b, Wnt-11) and their inhibitors (Dkk1, Axin1, sFRP3, sFRP5, Wif-1) surrounding the cartilage canals and osteochondral junction provides evidence of the complex interactions occurring during endochondral ossification.