MiR-152-5p suppresses osteogenic differentiation of mandible mesenchymal stem cells by regulating ATG14-mediated autophagy

Abstract

Background Osteoporosis affects the mandible resulting in bone loss. Though impairments are not life threatening, they affect a person's quality-of-life particularly vulnerable elderly. MicroRNAs (miRNAs) are novel regulatory factors that play an important role in regulating bone metabolism. Autophagy is evolutionarily conserved intracellular self-degradation process and is vital in the maintenance of both miRNA and bone homeostasis. However, the role of autophagy in the pathogenesis of miRNA regulating osteoporosis remains unclear. Methods In the study, we established a rat osteoporosis model induced by ovariectomy (OVX) and isolated mesenchymal stem cells from mandible (MMSCs-M). Several miRNAs were identified to regulate osteoporosis in some studies. qRT-PCR was applied to examine the expression of miRNA, autophagy and osteogenic differentiation-related genes. Western blotting assays were performed to detect the expression of autophagy and osteogenic differentiation proteins. Immunofluorescence and transmission electron microscope were used to verify the autophagy activity. Transfecting technology was used to enhance or suppress the expression of miR-152-5p which enable us to observe the relationship between miR-152-5p, autophagy and osteogenic differentiation. Additionally, the measurement of reactive oxygen species was used to investigate the mechanism of autophagy affecting osteogenic differentiation. Results We found an upregulated expression of miR-152-5p in MMSCs-M in OVX group. Downregulated autophagy-related gene, proteins and autophagosome were detected in vitro of OVX group compared with sham group. Moreover, downregulation of miR-152-5p promoted osteogenic differentiation of MMSCs-M as well as enhanced autophagy-related proteins in OVX group. Conversely, overexpression of miR-152-5p showed opposite effect in sham group. Meanwhile, we found Atg14 (autophagy-related protein homolog 14) was identified to be a direct target of miR-152-5p theoretically and functionally. In other words, we confirmed inhibition of miR-152-5p promoted the osteogenic differentiation via promoting ATG14-mediated autophagy. Furthermore, miR-152-5p/ATG14-mediated autophagy regulated osteogenic differentiation by reducing the endogenous ROS accumulation and maintaining cellular redox homeostasis. Conclusion Our data suggest that miR-152-5p is the first identified to regulate osteogenic differentiation by directly targeting autophagy-related protein ATG14 and regulating oxidative stress and therapeutic inhibition of miR-152-5p may be an efficient anabolic strategy for osteoporosis.

Hypoxia dissociates HDAC6/FOXO1 complex and aggregates them into nucleus to regulate autophagy and osteogenic differentiation

“…Noteworthy, either pathological or environmental hypoxia is considered to influence bone health, 40 and intermittent hypoxia can decrease bone mineral density in the mandible of growing rats 41 . Moreover, evidences have shown that autophagy activity was associated with osteogenic differentiation, 42 and autophagy can inhibit osteogenic differentiation of cells from mandible 43 . Therefore, we wanted to know if hypoxia could affect the autophagy and osteogenic differentiation and participate in the pathogenesis of periodontitis.…”

“…41 Moreover, evidences have shown that autophagy activity was associated with osteogenic differentiation, 42 and autophagy can inhibit osteogenic differentiation of cells from mandible. 43 Therefore, we wanted to know if hypoxia could affect the autophagy and osteogenic differentiation and participate in the pathogenesis of periodontitis.…”

Epigenetic Regulation of Autophagy in Bone Metabolism

“… 176 , 178 , 179 Additionally, in conditions like osteoporosis and osteoarthritis, abnormal DNA methylation affects autophagy, highlighting its role in bone health. 180 …”

Epigenetic regulation in metabolic diseases: mechanisms and advances in clinical study

“…Moreover, miR-100 reduction accelerates bone regeneration defects of BMSCs in osteoporotic mice by the AKT-mammalian target of rapamycin (mTOR) pathway. 252 Li et al 253 revealed that miR-152-5p is increased in MMSCs-M, and they observed autophagy-related genes, proteins, and autophagosomes in the ovariectomy (OVX) group. They found that downregulating miR-152-5p facilitates the osteogenic differentiation of MMSCs-M through accelerating autophagy-related protein homologue 14 (ATG14)-mediated autophagy with reduced accumulation of endogenous ROS.…”

“…They found that downregulating miR-152-5p facilitates the osteogenic differentiation of MMSCs-M through accelerating autophagy-related protein homologue 14 (ATG14)-mediated autophagy with reduced accumulation of endogenous ROS. 253 The balance between osteoblasts and osteoclasts is crucial for bone metabolism. A recent study indicated that delivering recombinant adeno-associated viral (rAAV) vectors to bone and modulating the expression of miR-214-3p and miR-34a-5p can influence both osteoblasts and osteoclasts to treat osteoporosis.…”