Metformin-Induced MicroRNA-34a-3p Downregulation Alleviates Senescence in Human Dental Pulp Stem Cells by Targeting CAB39 through the AMPK/mTOR Signaling Pathway

Abstract

Dental pulp stem cells (DPSCs) are ideal seed cells for the regeneration of dental tissues. However, DPSC senescence restricts its clinical applications. Metformin (Met), a common prescription drug for type 2 diabetes, is thought to influence the aging process. This study is aimed at determining the effects of metformin on DPSC senescence. Young and aging DPSCs were isolated from freshly extracted human teeth. Flow cytometry confirmed that DPSCs expressed characteristic surface antigen markers of mesenchymal stem cells (MSCs). Cell Counting Kit-8 (CCK-8) assay showed that a concentration of 100 μM metformin produced the highest increase in the proliferation of DPSCs. Metformin inhibited senescence in DPSCs as evidenced by senescence-associated β-galactosidase (SA-β-gal) staining and the expression levels of senescence-associated proteins. Additionally, metformin significantly suppressed microRNA-34a-3p (miR-34a-3p) expression, elevated calcium-binding protein 39 (CAB39) expression, and activated the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) signaling pathway. Dual-luciferase reporter assay confirmed that CAB39 is a direct target for miR-34a-3p. Furthermore, transfection of miR-34a-3p mimics promoted the senescence of DPSCs, while metformin treatment or Lenti-CAB39 transfection inhibited cellular senescence. In conclusion, these results indicated that metformin could alleviate the senescence of DPSCs by downregulating miR-34a-3p and upregulating CAB39 through the AMPK/mTOR signaling pathway. This study elucidates on the inhibitory effect of metformin on DPSC senescence and its potential as a therapeutic target for senescence treatment.

Hypoxic preconditioning rejuvenates mesenchymal stem cells and enhances neuroprotection following intracerebral hemorrhage via the miR-326-mediated autophagy

“…MiRNAs, endogenous small noncoding RNA molecules, have been reported to play crucial roles in mediating the cellular senescence of stem cells [ 24 , 25 , 71 ], examples include microRNA-206 [ 15 ], let-7, miRNA-23a, miRNA-26a, miRNA-30a [ 72 ], microRNA-34a-3p [ 73 ], miRNA-145a [ 27 ], miRNA-1292 [ 26 ], miRNA-15a/15b [ 74 ], miRNA-155-5p [ 43 ], and miRNA-199a-5p [ 49 ]. Using microarray and bioinformatic analysis, we compared miRNA expression levels in OM-MSCs cultured in normoxia and hypoxia.…”

Low magnitude vibration alleviates age-related bone loss by inhibiting cell senescence of osteogenic cells in naturally senescent rats

“…Therefore, we explore the anti-aging effect of LMV on the bone from aged rats. SA-β-Gal was a method which many studies had used to verify the senescence reversal [ 32 – 34 ]. In our study, we used SA-β-Gal to verify reversal effect of LMV on osteogenic cell senescence.…”

Metformin pre-conditioning enhances the angiogenic ability of the secretome of dental pulp stem cells

“…Thus, researchers have constantly used biomolecules to prolong the regenerative potential of DPSCs by inhibiting senescence. Metformin has been shown to attenuate senescence in DPSCs with 100 μM metformin, inducing the highest rate of DPSC proliferation ( Zhang et al, 2021 ). In addition to inhibiting senescence, researchers have explored ways to augment several key properties, including the potential for odontogenic, osteogenic, and angiogenic differentiation, which carry a wide array of potential clinical applications.…”