High Glucose Exacerbates TNF-α-Induced Proliferative Inhibition in Human Periodontal Ligament Stem Cells through Upregulation and Activation of TNF Receptor 1

Abstract

Objective. This research is aimed at investigating how high glucose affects the proliferation and apoptosis in periodontal ligament stem cells (PDLSCs) in the presence of TNF-α. Methods. PDLSCs obtained from periodontal healthy permanent teeth were treated under either high-glucose condition (30 mmol/L, G30 group) or normal glucose condition (5.6 mmol/L, G5.6 group) in the presence or absence of TNF-α (10 ng/ml) for 2 to 6 days. Cell proliferation and cell cycle were evaluated by CCK-8, EdU incorporation assay, and flow cytometry. Cell apoptosis was assessed by annexin V/PI staining. Protein expression was detected by western blotting. Cellular ROS expression was evaluated by CellROX labeling and flow cytometry. Specific antibodies targeting TNFR1 and TNFR2 were used to block TNF-α signaling. Vitamin C was also used to verify if the blockage of ROS can rescue PDLSCs in the presence of high glucose and TNF-α. Results. CCK-8 assay showed that high glucose exacerbated TNF-α-induced cell viability inhibition (57.0%, 85.2%, and 100% for the G30+TNF-α group, G5.6+TNF-α group, and control group, respectively) on day 6. High glucose increased protein expression of TNFR1 compared with the control group on day 2 (1.24-fold) and day 6 (1.26-fold). Blocking TNFR1 totally reversed the proliferative inhibition in G30+TNF-α group. The addition of vitamin C or TNFR1 antibody totally reversed the elevation of intracellular ROS expression caused by high glucose and TNF-α. Vitamin C partially restored cell proliferation in the presence of high glucose and TNF-α. Conclusion. High glucose exacerbates TNF-α-induced proliferative inhibition in human periodontal ligament stem cells through the upregulation and activation of TNF receptor 1. Inhibition of intracellular ROS expression by vitamin C partially rescues PDLSCs in terms of cell proliferation.

High‐glucose concentration aggravates TNF‐alpha‐induced cell viability reduction in human CD146‐positive periodontal ligament cells via TNFR‐1 gene demethylation

“…The blockade of TNFR‐1 effectively recovered cell viability in the presence of both high‐glucose concentrations and TNF‐alpha, indicating that TNFR‐1 played a key role in mediating cell viability. In our previous study (Zhu et al, 2020), we found that the expression of TNFR‐2 was unchanged in the presence of high‐glucose concentrations. The blockade of TNFR‐2 through the use of an antibody did not restore cell viability against high‐glucose concentrations and TNF‐alpha.…”

“…Our previous study demonstrated that CD146 + PDLCs isolated from human PDLCs presented higher colony efficiency and higher potential of osteogenic and adipogenic differentiation than those exhibited by CD146 − PDLCs. CD146 + PDLCs expressed MSC‐specific surface markers, including CD90, CD105, CD44, CD73, CD146, and Stro‐1 (Zhu et al, 2020, 2013). Additionally, CD146 − PDLCs exhibited little response to TNF‐alpha and expressed low levels of TNFR‐1 and TNFR‐2 (Zhu et al, 2013).…”

“…Additionally, a 6‐year clinical follow‐up study found that transplantation using PDLSCs regenerated periodontal damage in periodontitis patients (Feng et al, 2010). Our previous study revealed that CD146 + periodontal ligament cells (PDLCs) isolated from human PDL expressed the same surface markers like those found on MSCs, and these cells possessed higher colony‐forming efficiency and osteogenic potential than those exhibited by CD146 − PDLCs (Zhu et al, 2020, 2013).…”

“…Additionally, our previous data indicated that treatment of PDLSCs with both high‐glucose concentration and TNF‐alpha caused cell cycle arrest in the G1 phase and led to cell apoptosis. TNFR‐1 was upregulated by high‐glucose concentration and may be responsible for the inhibition of PDLSC cell survival (Zhu et al, 2020). However, the mechanism by which high‐glucose concentration increases TNFR‐1 expression is not fully understood.…”

Protective effects of PAMAM dendrimers against ANIT-induced cholestatic liver injury in mice

“…The cells were divided into four groups: (1) Control group; (2) TNF-α group:stimulated with TNF-α (10 ng/ml) [17]alone for 24 hours; (3) -COOH + TNF-α group :preincubation with G4.5-COOH (7uM) for 4 h before TNF-α stimulation; (4) GW9662 +-COOH + TNF-α group : GW9662 (10uM/ml) [18]was added for 0.5 h and then preincubation with G4.5-COOH (7uM) for 4 h before TNF-α stimulation.…”