2024, Vol. 28 ›› Issue (20): 3190-3195

Role and mechanism of miR-155/leptin receptor/adenosine phosphate-dependent protein kinase axis in tuberculin-induced osteoclast formation

Wang Zengshun, Suonan Angxiu, Liu Limin, Zhou Jingyuan   

Abstract: BACKGROUND: Abnormal activation of osteoclasts plays an important role in the bone destruction due to spinal tuberculosis. During the pathogenesis of osteoporosis, miR-155 knockdown activates adenosine phosphate-dependent protein kinase (AMPK) by increasing the expression of leptin receptors, thereby inhibiting osteoclast differentiation and bone resorption. However, the role of miR-155/leptin receptor(LEPR)/AMPK axis in the bone destruction due to spinal tuberculosis remains unclear.
OBJECTIVE: To investigate the role and mechanism of miR-155/LEPR/AMPK axis in tuberculin-induced osteoclast formation.
METHODS: RAW264.7 cells were cultured and treated with different concentrations of purified protein derivative (PPD) (1.0, 2.5, 5.0, 10.0 IU/mL) and transfected with negative control (NC) sequence or miR-155 inhibitor, NC siRNA sequence or LEPR siRNA sequence. Tartrate resistant acid phosphatase staining was used to detect the number of osteoclasts. Fluorescence quantitative PCR was used to detect the expression of miR-155. Western blot was used to detect the expression of LEPR and p-AMPK. Double luciferase reporter gene was used to verify miR-155 targeting LEPR.
RESULTS AND CONCLUSION: Compared with the control group, the number of osteoclasts and the expression level of miR-155 significantly increased, while the expression level of LEPR and p-AMPK significantly decreased in 2.5, 5.0, and 10.0 IU/mL PPD groups (P < 0.05). Compared with NC+5.0 IU/mL PPD group, the number of osteoclasts and the expression level of miR-155 significantly decreased, while the expression level of LEPR and p-AMPK significantly increased in the miR-155 inhibitor+5.0 IU/mL PPD group (P < 0.05). Compared with the NC group, the fluorescence activity of LEPR wild-type double luciferase reporter gene was increased in the miR-155 inhibitor group, and decreased in the miR-155 mimic group (P < 0.05). Compared with si-NC+miR-155 inhibitor+5.0 IU/mL PPD group, the expression level of miR-155 had no significant change, the number of osteoclasts significantly increased, and the expression levels of LEPR and p-AMPL significantly decreased in si-LEPR+miR-155 inhibitor+5.0 IU/mL PPD group (P < 0.05). To conclude, tuberculin can induce osteoclast formation by increasing miR-155 expression and inhibiting downstream LEPR expression and AMPK activation.

Key words: osteoclast, tuberculin, mononuclear macrophages, bone resorption, miR-155, leptin receptor, AMPK