PRMT6/LMNA/CXCL12 signaling pathway regulated the osteo/odontogenic differentiation ability in dental stem cells isolated from apical papilla

Modulation of regenerative responses by retinoic and ascorbic acids in human apical papilla cells

OBJECTIVE

This study investigated the bioactive effects of retinoic acid and ascorbic acid on hSCAPs in vitro.

DESIGN

Cells were obtained from human third molars (n=4) and characterized for mesenchymal stem cell markers by flow cytometry. The experimental groups: control (α-MEM); vehicle control group (α-MEM + 0.17 % DMSO); retinoic acid 0.1, 1, and 10 µM; and ascorbic acid 3, 30, and 300 µM (n=8) were tested for cell viability (alamarBlue; 1, 3, and 7 days), total collagen synthesis (Sirius Red; 1 and 7 days), mineralized matrix formation (Alizarin red; 14 days), and the regulation of gene expression related to mineralization (ALPL and DSPP), cell migration (ITGAV and CXCL12) angiogenesis (VEGFA) and collagen synthesis (COL1A1 and COL3A1; RT-qPCR) on 1 and 7 days. ACTB and GAPDH were used as reference genes. Data were analyzed by ANOVA and complementary tests at a 5 % significance level.

RESULTS

Ascorbic acid 300 µM increased viability, and retinoic acid reduced it dose-dependently. Retinoic acid 0.1 µM and ascorbic acid 30 and 300 µM increased mineralized matrix formation and total collagen synthesis, and retinoic acid 10 µM decreased. On day 1, 0.1 µM retinoic acid upregulated the gene expression of COL1A1, COL3A1, VEGFA, CXCL12, ALPL, DSPP e ITGAV, and 300 µM ascorbic acid upregulated COL1A1, COL3A1 and DSPP. However, on day 7, retinoic acid downregulated ALPL, COL3A1, CXCL12, and VEGFA and downregulated ITGAV and VEGFA.

CONCLUSION

Retinoic acid 0.1 µM and ascorbic acid 300 µM biostimulated hSCAPs to differentiate into pro-regenerative phenotypes with potential application for REPs.

Cold exposure impacts DNA methylation patterns in cattle sperm

DNA methylation is influenced by various exogenous factors such as nutrition, temperature, toxicants, and stress. Bulls from the Pacific Northwest region of the United States and other northern areas are exposed to extreme cold temperatures during winter. However, the effects of cold exposure on the methylation patterns of bovine sperm remain unclear. To address, DNA methylation profiles of sperm collected during late spring and winter from the same bulls were analyzed using whole genome bisulfite sequencing (WGBS). Bismark (0.22.3) were used for mapping the WGBS reads and R Bioconductor package DSS was used for differential methylation analysis. Cold exposure induced 3,163 differentially methylated cytosines (DMCs) with methylation difference ≥10% and a q-value < 0.05. We identified 438 differentially methylated regions (DMRs) with q-value < 0.05, which overlapped with 186 unique genes. We also identified eight unique differentially methylated genes (DMGs) (Pax6, Macf1, Mest, Ubqln1, Smg9, Ctnnb1, Lsm4, and Peg10) involved in embryonic development, and nine unique DMGs (Prmt6, Nipal1, C21h15orf40, Slc37a3, Fam210a, Raly, Rgs3, Lmbr1, and Gan) involved in osteogenesis. Peg10 and Mest, two paternally expressed imprinted genes, exhibited >50% higher methylation. The differential methylation patterns of six distinct DMRs: Peg10, Smg9 and Mest related to embryonic development and Lmbr1, C21h15orf40 and Prtm6 related to osteogenesis, were assessed by methylation-specific PCR (MS-PCR), which confirmed the existence of variable methylation patterns in those locations across the two seasons. In summary, cold exposure induces differential DNA methylation patterns in genes that appear to affect embryonic development and osteogenesis in the offspring. Our findings suggest the importance of replicating the results of the current study with a larger sample size and exploring the potential of these changes in affecting offspring development.

Spatiotemporal cellular dynamics and molecular regulation of tooth root ontogeny

Tooth root development involves intricate spatiotemporal cellular dynamics and molecular regulation. The initiation of Hertwig's epithelial root sheath (HERS) induces odontoblast differentiation and the subsequent radicular dentin deposition. Precisely controlled signaling pathways modulate the behaviors of HERS and the fates of dental mesenchymal stem cells (DMSCs). Disruptions in these pathways lead to defects in root development, such as shortened roots and furcation abnormalities. Advances in dental stem cells, biomaterials, and bioprinting show immense promise for bioengineered tooth root regeneration. However, replicating the developmental intricacies of odontogenesis has not been resolved in clinical treatment and remains a major challenge in this field. Ongoing research focusing on the mechanisms of root development, advanced biomaterials, and manufacturing techniques will enable next-generation biological root regeneration that restores the physiological structure and function of the tooth root. This review summarizes recent discoveries in the underlying mechanisms governing root ontogeny and discusses some recent key findings in developing of new biologically based dental therapies.