microRNA-142-3p regulates osteogenic differentiation of human periodontal ligament stem cells via mediating SGK1.

OBJECTIVE: Human periodontal ligament stem cells (hPDLSCs) refer to one kind of somatic stem cells that are capable of differentiating into multiple cell kinds and undergoing robust clonal self-renewal. This work was unearthed to elucidate the possible molecular mechanism of miR-142-3p in mediating osteogenic differentiation of hPDLSCs by targeting SGK1. METHODS: The hPDLSCs were isolated, cultured, and identified. hPDLSCs were identified by immunofluorescence staining and multiple differentiation ability detection. Cell proliferation ability was assessed by CCK-8 assay. hPDLSCs were induced using osteogenic differentiation medium. ALP activity was detected by alkaline phosphatase (ALP) staining  and ALP activity assay, and mineralized nodule formation was determined by alizarin red staining. The expression levels of osteogenic differentiation marker proteins ALP, RUNX2, and OCN were measured by RT-qPCR. miR-142-3p candidate targets were obtained through bioinformatics analysis. The relationship between miR-142-3p and SKG1 was verified. RESULTS: miR-142-3p in hPDLSCs after osteogenic induction was down-regulated. Elevated miR-142-3p restricted hPDLSCs proliferation, and diminished ALP activity and mineralized nodule formation, as well as the expression of ALP, RUNX2, and OCN, while miR-142-3p inhibition led to inverse results. miR-142-3p inhibited SKG1 expression. SKG1 overexpression promoted hPDLSC proliferation and osteogenic differentiation, and reversed the inhibitory function of miR-142-3p on hPDLSCs. CONCLUSION: This study highlights that miR-142-3p represses osteogenic differentiation of hPDLSCs by reducing SGK1 expression.

Mesiodistal angulation and faciolingual inclination of each whole tooth in 3-dimensional space in patients with near-normal occlusion.

INTRODUCTION: An important objective of orthodontic treatment is to obtain the correct mesiodistal angulation and faciolingual inclination for all teeth. Current techniques are based on crown angulation and inclination standards, and not enough attention has been given to the roots. In this study, we report the mesiodistal angulation and faciolingual inclination of each whole tooth including the root in patients with near-normal occlusion. METHODS: We screened 1840 patients who had cone-beam computed tomography scans taken before treatment to obtain a sample of 76 patients with near-normal occlusion. Using our custom University of Sourthern California root vector analysis software program, we digitized the crown and root centers to determine the "true" long axis of each tooth from where the mesiodistal angulation and the faciolingual inclination were measured. RESULTS: The means and standard deviations for the mesiodistal angulation and the faciolingual inclination of each whole tooth were calculated. The maxillary angulations of the teeth started from approximately 6° for the central incisors, slightly increased for the lateral incisors, and peaked at 11° for the canines; then it gradually decreased to just above 0° for the first molars and eventually reached -6° for the second molars. The mandibular angulations started from about 0° for the incisors and increased to 17.5° for the second molars. The maxillary inclination was the highest at 33.5° for the central incisors, decreased to about 0° at the second premolars, and then increased for the 2 molars. The mandibular inclination also was the highest at 26.5° for the central incisors, decreased also to about 0° at the second premolars, and continued to decrease for the 2 molars. For the opposing tooth pairs, the interdental mesiodistal angulations always remained within 10° from one another, whereas the interdental faciolingual inclination increased from about 120° for the incisors to about 180° for the second premolars and the 2 molars. CONCLUSIONS: We obtained the average mesiodistal angulation and faciolingual inclination for each whole tooth measured from its long axis digitized on the cone-beam computed tomography volumetric images of 76 patients with near-normal occlusion. We found distinctive angulation and inclination relationships between the neighboring and opposing teeth. This information can be used in addition to the crown standards for positioning each whole tooth properly in the arches.

Identifying individual-specific microbial DNA fingerprints from skin microbiomes.

Skin is an important ecosystem that links the human body and the external environment. Previous studies have shown that the skin microbial community could remain stable, even after long-term exposure to the external environment. In this study, we explore two questions: Do there exist strains or genetic variants in skin microorganisms that are individual-specific, temporally stable, and body site-independent? And if so, whether such microorganismal genetic variants could be used as markers, called "fingerprints" in our study, to identify donors? We proposed a framework to capture individual-specific DNA microbial fingerprints from skin metagenomic sequencing data. The fingerprints are identified on the frequency of 31-mers free from reference genomes and sequence alignments. The 616 metagenomic samples from 17 skin sites at 3-time points from 12 healthy individuals from Integrative Human Microbiome Project were adopted. Ultimately, one contig for each individual is assembled as a fingerprint. And results showed that 89.78% of the skin samples despite body sites could identify their donors correctly. It is observed that 10 out of 12 individual-specific fingerprints could be aligned to Cutibacterium acnes. Our study proves that the identified fingerprints are temporally stable, body site-independent, and individual-specific, and can identify their donors with enough accuracy. The source code of the genetic identification framework is freely available at https://github.com/Ying-Lab/skin_fingerprint.