Comprehensive Transcriptome Analysis of mRNA Expression Patterns Associated With Enhanced Biological Functions in Periodontal Ligament Stem Cells Subjected to Short-Term Hypoxia Pretreatment.

Zhi-Bang Li,Hui-Qi Yang,Kun Li,Shao-Hua Ge,Yang Yu,Su-Su Feng,Yuan Yin

doi:10.3389/fgene.2022.797055

Abstract

Short-term hypoxia pretreatment significantly enhances periodontal ligament stem cell (PDLSC)-based periodontal tissue regeneration by improving various cellular biological functions, but the underlying mechanisms remain unclear. In this study, based on RNA sequencing (RNA-seq), we comprehensively analyzed the possible regulatory mechanisms of the short-term hypoxic effects on the biological functions of healthy and inflammatory PDLSCs. A total of 134 and 164 differentially expressed genes (DEGs) were identified under healthy and inflammatory conditions, respectively. Functional enrichment analyses indicated that DEGs under both conditions share certain biological processes and pathways, including metabolic processes, developmental processes, reproductive processes, localization, immune system processes and the HIF-1 signaling pathway. The DEGs identified under inflammatory conditions were more significantly enriched in cell cycle-related processes and immune-related pathways, while DEGs identified under healthy condition were more significantly enriched in the TGF-β signaling pathway. A protein-protein interaction network analysis of the 59 DEGs in both conditions was performed, and 15 hub genes were identified. These hub genes were mainly involved in glycolysis, the cellular response to hypoxia, cell differentiation, and immune system processes. In addition, we found that hypoxia induced significant differential expression of genes associated with proliferation, differentiation, migration, apoptosis and immunoregulation under both healthy and inflammatory conditions. This study provides comprehensive insights into the effects of short-term hypoxia on the biological functions of PDLSCs and suggests a potentially feasible strategy for improving the clinical effectiveness of cell-based periodontal tissue engineering.

Highlights

Periodontitis is a complex infectious disease that can lead to loss of connective tissue and bone support, which results in the formation of periodontal pockets around teeth (Pihlstrom et al, 2005)
Our RNA sequencing (RNA-seq) analysis was performed with 12 samples; and from each sample an average of 6.83 G worth of data were obtained, and 24,961 genes were detected
We constructed differentially expressed RNA profiles by RNA-seq and demonstrated that gene expression was significantly changed under hypoxic conditions in both healthy and inflammatory Human PDLSCs (hPDLSCs)

Summary

Introduction

Periodontitis is a complex infectious disease that can lead to loss of connective tissue and bone support, which results in the formation of periodontal pockets around teeth (Pihlstrom et al, 2005). The basic principle of periodontal therapy involves controlling biofilm formation and other contributing factors, deescalating inflammation, and regenerating damaged periodontal tissue. In this regard, the clinical outcomes of reduced tissue inflammation and pocket depths can be achieved by conventional nonsurgical therapy, effective self-care and, in some cases, the administration of local or systemic antibiotics (Pihlstrom et al, 2005; Slots, 2017). The local or systemic administration of biomaterials and growth factors regenerates damaged periodontal support, clinical trials have revealed that this approach produces limited effects, and these findings reveal that true periodontal regeneration remains an ongoing challenge for dentists (Xu Q. et al, 2019)

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Discussion

Conclusion