Periodic Mechanical Stress Induces Extracellular Matrix Expression and Migration of Rat Nucleus Pulposus Cells Through Src-GIT1-ERK1/2 Signaling Pathway

Abstract

Background/Aims: Periodic mechanical stress has been shown to promote extracellular matrix (ECM) synthesis and cell migration of nucleus pulposus (NP) cells, however, the mechanisms need to be fully elucidated. The present study aimed to investigate the signal transduction pathway in the regulation of NP cells under periodic mechanical stress. Methods: Primary rat NP cells were isolated and seeded on glass slides, and then treated in our self-developed periodic stress field culture system. To further explore the mechanisms, data were analyzed by scratch-healing assay, quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis, western blotting, and co-immunoprecipitation assay. Results: Under periodic mechanical stress, the mRNA expression of ECM collagen 2A1 (Col2A1) and aggrecan, and migration of NP cells were significantly increased (P < 0.05 for each), associating with increases in the phosphorylation of Src, GIT1, and ERK1/2 (P < 0.05 for each). Pretreatment with the Src inhibitor PP2 reduced periodic mechanical stress-induced ECM synthesis and cell migration of NP cells (P < 0.05 for each), while the phosphorylation of GIT1 and ERK1/2 were inhibited. ECM synthesis, cell migration, and phosphorylation of ERK1/2 were inhibited after pretreatment with the small interfering RNA for GIT1 in NP cells under periodic mechanical stress (P < 0.05 for each), whereas the phosphorylation of Src was not affected. Pretreatment with the ERK1/2 inhibitor PD98059 reduced periodic mechanical stress-induced ECM synthesis and cell migration of NP cells (P < 0.05 for each). Co-immunoprecipitation assay showed that there was a direct interaction between Src and GIT1 and between GIT1 and ERK1/2. Conclusion: In conclusion, periodic mechanical stress induced ECM expression and migration of NP cells via Src-GIT1-ERK1/2 signaling pathway, playing an important role in regulation of NP cells.

Effects of periodic mechanical stress on cytoskeleton dependent lipid raft-induced integrin ɑ1 activation in rat nucleus pulposus cells

“…Therefore, this study of the nucleus pulposus cell regulation mechanism under the stress environment is closer to reality and has more profound significance. We demonstrated that the Src-GIT1-ERK1/2 pathway (Gao, 2018) and integrin α1-PLCγ1 (Gao, 2016a) were involved in the regulation chain. Combined with this study, from cytoskeleton, cell membrane structure (lipid rafts)…”

“…In vitro, it is known that mechanical stress can regulate NP cell bioactivities (Kuo, 2014;Feng, 2018;Kim, 2009). On the one hand, appropriate periodic mechanical stress (PMS) can promote NP cell proliferation and extracellular matrix (ECM) synthesis (Gao, 2018;Gao, 2016a;Gao, 2016b). On the other hand, the abnormal stress environment is one of the most important factors leading to NP cell degeneration (Kuo, 2014).…”

Dynamics of CD44+ bovine nucleus pulposus cells with inflammation

“…CD45 main function is mediated by its intracellular segment’s phosphatase activity, whose major targets are the Src-family kinases (SFK) 74 , which phosphorylation has been involved in the central sensitization and radicular pain from lumbar discs’ herniation 75 . Interestingly, SFKs’ phosphorylation has also been associated with COL2A1 and ACAN expression in NP cells under periodic mechanical stress 76 . In our study CD45 increase is linked to the expression of CD44.…”

External axial Stress Induces&nbsp;Rabbit Tibia Fracture Healing via&nbsp;Stimulating&nbsp;the Expression of VEGF, CD34, BMP-2 and TGF-β1

“…In recent decades, many researches indicated that moderate stress stimulation could promote bone healing. On the one hand, mechanical stress can indirectly stimulate osteoblasts formation, facilitate the proliferation and differentiation of osteoblasts and the formation of extracellular matrix [14,15]. On the other hand, mechanical stress can also promote cell factors release to improve skeleton vascularization and mineralizaion.…”