Overexpression of microRNA-185 alleviates intervertebral disc degeneration through inactivation of the Wnt/β-catenin signaling pathway and downregulation of Galectin-3

Abstract

Background: Recent studies have found that microRNAs (miRNAs) play a critical role in development and progression of intervertebral disc degeneration. In the present study, we examined the role of miR-185 in nucleus pulposus cell behavior in vitro and the histological changes of intervertebral disc tissue in intervertebral disc degeneration rat models in vivo. Methods: Intervertebral disc degeneration models were developed in Sprague-Dawley rats. Intervertebral disc tissue was collected for histological evaluation after miR-185 agomir/agomir transduction. Next, nucleus pulposus tissues were collected from lumbar intervertebral discs to isolate nucleus pulposus cells, which were treated with miR-185 mimic/inhibitor and an inhibitor of the Wnt signaling pathway to assess cell viability and apoptosis. Results: We observed a high expression of Galectin-3 in nucleus pulposus cells of rats with intervertebral disc degeneration. Bioinformatics prediction and dual-luciferase reporter assay confirmed that miR-185 specifically binds to and negatively regulates Galectin-3. Furthermore, we found that miR-185 inhibition resulted in increased expression of Galectin-3, pro-autophagy factors (LC3 and Beclin-1), and pro-apoptosis factors (caspase-3 and Bax), along with the activation of the Wnt/b-catenin signaling pathway. Moreover, the gain-and loss-of-function studies suggested that miR-185 overexpression promoted cell viability and inhibited nucleus pulposus cell apoptosis and autophagy via inactivation of the Wnt/b-catenin signaling pathway. Moreover, miR-185 agomir alleviated the histological changes observed in intervertebral disc tissues in intervertebral disc degeneration rats, which helped us validate the results observed in vitro. Conclusions: Overexpression of miR-185 promotes nucleus pulposus cell viability and reduces the histological changes observed in intervertebral disc tissues in rats with intervertebral disc degeneration via inactivation of the Wnt/b-catenin signaling pathway and Galectin-3 inhibition. Our findings also highlight the potential of miR-185 as a promising novel therapeutic target to prevent and control intervertebral disc degeneration.

MicroRNAs in Intervertebral Disc Degeneration, Apoptosis, Inflammation, and Mechanobiology

“…These expression levels, as well as the activation of the Wnt/ β-catenin signaling pathway, increased even more when miR-185 was inhibited. However, transfection of miR-185 in vitro and injection of miR-185 in vivo attenuated these effects, leading to decreased rates of apoptosis [61]. miR-143-5p, on the other hand, was shown to be upregulated in degenerated NP tissue of rats.…”

“…The most promising and thoroughly conducted studies investigating the role of miRNAs in IVD degeneration identified miR-185 and miR-143-5p to be associated with apoptosis. Both studies conducted in vivo experiments using DDD rat models established by needle puncture of the NP tissue [61,62]. miR-185 was found to be targeting galectin 3, a β-galactosidase-binding protein involved in apoptosis and the Wnt/β-catenin pathway [63,64].…”

CircRNA RERE Promotes the Oxidative Stress-Induced Apoptosis and Autophagy of Nucleus Pulposus Cells through the miR-299-5p/Galectin-3 Axis

“…Galectin-3 is a versatile protein orchestrating several physiological and pathophysiological processes in the human body [ 6 ]. Previous studies have shown that the expression of galectin-3 is upregulated in the NP cells and inhibition galectin-3 alleviates the spinal cord injury and IDD [ 7 , 8 ]. Cell therapy may be an effective way to repair IDD; as a strong immune suppressor, TGF- β has been shown to inhibit inflammation respond effectively [ 9 ].…”

“…The competing endogenous RNA (ceRNA) hypothesis is an important mechanism that allows circRNAs in cancers by sponging microRNAs (miRNAs) to modulate mRNAs [ 24 ]. Increasing evidence shows that the circRNA and miRNA can regulate apoptosis and autophagy of cells [ 7 , 25 , 26 ], including NP cells [ 27 ]. These identified ceRNA interaction aces may be crucial targets for treatment of IDD [ 28 ].…”

Regulation of autophagy by miRNAs in human diseases

“…For instance, in some patient samples, miR-21 blocks PTEN-mediated autophagy and promotes extracellular matrix (ECM) degradation, thus facilitating IDD progression; in few other cases, miR-21 increases the interleukin (IL)-6 inflammatory response to blunt autophagy [ 43 , 80 ]. Similarly, miRNAs (miR-129-5p, miR-185) blocking other upstream regulators of autophagy, like BECN-1 and GALECTIN-3, are also deemed responsible for IDD in other reports [ 95 , 101 ]. However, proteins directly involved in the autophagy pathway are also regulated by miRNAs in human IDD.…”