@Article{biocell.2024.049562,
AUTHOR = {LEI SHI, JIANSHI YIN, YU CHEN, JIANGANG SHI, JINHAO MIAO},
TITLE = {<i>DAPK2</i> promotes autophagy to accelerate the progression of ossification of the posterior longitudinal ligament through the <i>mTORC1</i> complex},
JOURNAL = {BIOCELL},
VOLUME = {48},
YEAR = {2024},
NUMBER = {9},
PAGES = {1389--1400},
URL = {http://www.techscience.com/biocell/v48n9/57806},
ISSN = {1667-5746},
ABSTRACT = { <b>Background:</b> Ossification of the posterior longitudinal ligament (OPLL) is a prevalent condition in orthopedics. While death-associated protein kinase 2 (<i>DAPK2</i>) is known to play roles in cellular apoptosis and autophagy, its specific contributions to the advancement of OPLL are not well understood. <b>Methods:</b> Ligament fibroblasts were harvested from patients diagnosed with OPLL. Techniques such as real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) and Western blot analysis were employed to assess <i>DAPK2</i> levels in both ligament tissues and cultured fibroblasts. The extent of osteogenic differentiation in these cells was evaluated using an alizarin red S (ARS) staining. Additionally, the expression of ossification markers and autophagy markers was quantified. The autophagic activity was further analyzed through <i>LC3</i> immunofluorescence and transmission electron microscopy (TEM). An <i>in vivo</i> heterotopic bone formation assay was conducted in mice to assess the role of <i>DAPK2</i> in ossification. <b>Results:</b> Elevated <i>DAPK2</i> expression was confirmed in both OPLL patient tissues and derived fibroblasts, in contrast to non-OPLL controls. Silencing of <i>DAPK2</i> significantly curtailed osteogenic differentiation and autophagy in these fibroblasts, evidenced by decreased levels of <i>LC3</i>, and <i>Beclin1</i>, and reduced autophagosome formation. Additionally, <i>DAPK2</i> was found to inhibit the mechanistic target of the rapamycin complex 1 (<i>mTORC1</i>) complex’s activity. <i>In vivo</i> studies demonstrated that <i>DAPK2</i> facilitates ossification, and this effect could be counteracted by the <i>mTORC1</i> inhibitor rapamycin. <b>Conclusion:</b> <i>DAPK2</i> enhances autophagy and osteogenic processes in OPLL through modulation of the <i>mTORC1</i> pathway.},
DOI = {10.32604/biocell.2024.049562}
}