Long non-coding RNA LINC01133 regulates cementogenic differentiation of human periodontal ligament stem cells by modulating mitochondrial functions

Abstract

Objective: To investigate the effects of long non-coding RNA (lncRNA) LINC01133 on the cementogenic differentiation of human periodontal ligament stem cells (hPDLSC) and the underlying mechanism. Methods: A total of 12 teeth were harvested from 10 patients aged 17-30 years in the Department of Oral and Maxillofacial Surgery, School of Stomatology, The Fourth Military Medical University for impacted or orthodontic reasons from September 2021 to January 2022. The hPDLSCs were isolated from the teeth and transfected with small interfering RNA-LINC01133 (si-LINC01133) or small interfering RNA-negative control (si-NC). The si-LINC01133 was regarded as the experimental group, and the si-NC was regarded as the control one. The silencing efficiency of LINC01133 in the hPDLSCs was evaluated by real-time quantitative PCR (RT-qPCR). Western blotting was used to detect the protein expression levels of cementogenic differentiation-related factors including bone sialoprotein (BSP), cementum attachment protein (CAP), and cementum protein-1 (CEMP-1). Mitochondrial reactive oxygen species (mtROS) production was assessed using the MitoSox by flow cytometry. Mitochondrial membrane potential (MMP) was detected by JC-1 fluorescence staining. Mitochondrial respiratory chain complexes proteins including NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 8 (NDUFB8), succinate dehydrogenase complex flavoprotein subunit A (SDHA), ubiquinol-cytochrome c reductase core protein 1 (UQCR1), cytochrome c oxidase subunit 4 isoform 1 (COXⅣ), and ATP synthase F1 subunit alpha (ATP5A) were evaluated by Western blotting. Results: The expression levels of LINC01133 could be suppressed by more than 60% with si-LINC01133 (control group: 1.000±0.000, experimental group: 0.385±0.128) (t=10.72, P<0.01). Suppression of LINC01133 in hPDLSCs decreased the levels of cementogenic differentiation-related proteins including BSP (control group: 1.000±0.000, experimental group: 0.664±0.179) (t=4.62, P<0.01) and CAP (control group: 1.000±0.000, experimental group: 0.736±0.229) (t=2.83, P<0.05). Suppression of LINC01133 in hPDLSCs increased the production of mtROS (control group: 1.000±0.000, experimental group: 1.458±0.185) (t=4.96, P<0.05) and the expression of NDUFB8 (control group: 1.000±0.000, experimental group: 1.683±0.397) (t=3.45, P<0.05), as well as decreased MMP levels (control group: 1.000±0.000, experimental group: 0.209±0.029) (t=53.99, P<0.01) and the expression of SDHA (control group: 1.000±0.000, experimental group: 0.428±0.228) (t=5.02, P<0.05). No significant changes in the UQCR1, COXⅣ, and ATP5A expression levels were found between the control group and exprimental group (P>0.05). Conclusions: LINC01133 regulates the cementogenic differentiation of hPDLSCs possibly via modulating the mitochondrial functions.