Leptin Induces MMP-1 Expression Through the RhoA/ERK1/2/NF-κB Axis in Human Intervertebral Disc Cartilage Endplate-Derived Stem Cells

Kuo-Feng Hua,1,2,* Lan-Hui Li,3,* Hsin-Chiao Yu,4 Wei-Ting Wong,1 Hsien-Ta Hsu4,5 1Department of Biotechnology and Animal Science, National Ilan University, Yilan, 26047, Taiwan; 2Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, 404333, Taiwan; 3Department of Laboratory Medicine, Linsen, Chinese Medicine and Kunming Branch, Taipei City Hospital, Taipei, 108, Taiwan; 4Division of Neurosurgery, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, 231, Taiwan; 5School of Medicine, Buddhist Tzu Chi University, Hualien, 970, Taiwan*These authors contributed equally to this workCorrespondence: Hsien-Ta Hsu, Division of Neurosurgery, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 289, Jianguo Road, Xindian Dist, New Taipei City, 231016, Taiwan, Tel +866-2-6628-9779, Email j1208192@ms45.hinet.netPurpose: Intervertebral disc (IVD) degeneration, associated with aging, may cause low back pain and disability, with obesity as a significant risk factor. In a prior study, we found a positive correlation between IVD degeneration and levels of matrix metalloproteinase-1 (MMP-1) and leptin. Yet, the interaction between MMP-1 and leptin in IVD degeneration is unclear. Our research seeks to explore leptin’s influence on MMP-1 expression and the underlying mechanisms in human intervertebral disc cartilage endplate-derived stem cells, specifically SV40 cells.Methods: The mRNA and protein expression in leptin-stimulated SV40 cells were assessed using RT-real-time PCR and Western blotting or ELISA, respectively. We examined leptin-mediated RhoA activation through a GTP-bound RhoA pull-down assay. Furthermore, the phosphorylation levels of mitogen-activated protein kinases and AKT in leptin-stimulated SV40 cells were analyzed using Western blotting. The activation of NF-κB by leptin was investigated by assessing phosphorylation of IKKα/β, IκBα, and NF-κB p65, along with the nuclear translocation of NF-κB p65. To understand the underlying mechanism behind leptin-mediated MMP-1 expression, we employed specific inhibitors.Results: Leptin triggered the mRNA and protein expression of MMP-1 in SV40 cells. In-depth mechanistic investigations uncovered that leptin heightened RhoA activity, promoted ERK1/2 phosphorylation, and increased NF-κB activity. However, leptin did not induce phosphorylation of JNK1/2, p38, or AKT. When we inhibited RhoA, ERK1/2, and NF-κB, it resulted in a decrease in MMP-1 expression. Conversely, inhibition of reactive oxygen species and NADPH oxidase did not yield the same outcome. Additionally, inhibiting RhoA or ERK1/2 led to a reduction in leptin-induced NF-κB activation. Moreover, inhibiting RhoA also decreased leptin-mediated ERK1/2 phosphorylation.Conclusion: These results indicated that leptin induced MMP-1 expression in SV40 cells through the RhoA/ERK1/2/NF-κB axis. This study provided the pathogenic role of leptin and suggested the potential therapeutic target for IVD degeneration. Keywords: intervertebral disc degeneration, leptin, matrix metalloproteinase, intervertebral disc cartilage endplate-derived stem cells, RhoA, ERK1/2