Related Experiment Video
Updated: Oct 25, 2025
Identifying Microglia and Peripheral Infiltrating Macrophages in the Injured Spinal Cords Using Flow Cytometry
Published on: June 24, 2025
Magnoflorine Alleviates "M1" Polarized Macrophage-Induced Intervertebral Disc Degeneration Through Repressing the
Feng Zhao1,2, Zhenye Guo2, Fushan Hou2
1Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou 215006, China.
Abstract:
Intervertebral disc degeneration (IDD) is related to the deterioration of nucleus pulposus (NP) cells due to hypertrophic differentiation and calcification. The imbalance of pro-inflammatory (M1 type) and anti-inflammatory (M2 type) macrophages contributes to maintaining tissue integrity. Here, we aimed to probe the effect of Magnoflorine (MAG) on NP cell apoptosis mediated by "M1" polarized macrophages. THP-1 cells were treated with lipopolysaccharide (LPS) to induce "M1" polarized macrophages. Under the treatment with increasing concentrations of MAG, the expression of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, IL-18), high mobility group box protein 1 (HMGB1), as well as myeloid differentiation factor 88 (MyD88), nuclear factor kappa B (NF-κB) and NOD-like receptor 3 (NLRP3) inflammasomes in THP-1 cells were determined. What's more, human NP cells were treated with the conditioned medium (CM) from THP-1 cells. The NP cell viability and apoptosis were evaluated. Western blot (WB) was adopted to monitor the expression of apoptosis-related proteins (Bax, Caspase3, and Caspase9), catabolic enzymes (MMP-3, MMP-13, ADAMTS-4, and ADAMTS-5), and extracellular matrix (ECM) compositions (collagen II and aggrecan) in NP cells. As a result, LPS evidently promoted the expression of pro-inflammatory cytokines and HMGB1, the MyD88-NF-κB activation, and the NLRP3 inflammasome profile in THP-1 cells, while MAG obviously inhibited the "M1″ polarization of THP-1 cells. After treatment with "M1" polarized THP-1 cell CM, NP cell viability was decreased, while cell apoptosis, the pro-inflammatory cytokines, apoptosis-related proteins, and catabolic enzymes were distinctly up-regulated, and ECM compositions were reduced. After treatment with MAG, NP cell damages were dramatically eased. Furthermore, MAG dampened the HMGB1 expression and inactivated the MyD88/NF-κB pathway and NLRP3 inflammasome in NP cells. In conclusion, this study confirmed that MAG alleviates "M1" polarized macrophage-mediated NP cell damage by inactivating the HMGB1-MyD88-NF-κB pathway and NLRP3 inflammasome, which provides a new reference for IDD treatment.
Insights
Magnoflorine (MAG) reduces intervertebral disc degeneration (IDD) by inhibiting M1 macrophage polarization and associated inflammation. This study shows MAG protects nucleus pulposus cells from damage mediated by inflammatory macrophages.
Area of Science:
- Biomedical Science
- Cell Biology
- Immunology
Background:
- Intervertebral disc degeneration (IDD) involves nucleus pulposus (NP) cell dysfunction, including hypertrophy and calcification.
- An imbalance between M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages exacerbates IDD.
- Understanding macrophage polarization's role is crucial for developing IDD treatments.
Purpose of the Study:
- To investigate the therapeutic effect of Magnoflorine (MAG) on NP cell apoptosis induced by M1-polarized macrophages.
- To elucidate the underlying molecular mechanisms involving the HMGB1-MyD88-NF-κB pathway and NLRP3 inflammasome.
Main Methods:
- THP-1 cells were polarized to M1 macrophages using lipopolysaccharide (LPS).
- The effects of MAG on M1 polarization, cytokine expression, and inflammasome activation were assessed.
- Human NP cells were treated with conditioned medium from M1 macrophages, with and without MAG, and analyzed for viability, apoptosis, protein expression, and extracellular matrix content via Western blot.
Main Results:
- LPS-induced M1 polarization increased pro-inflammatory cytokines, HMGB1, and activated MyD88-NF-κB and NLRP3 inflammasomes.
- MAG treatment inhibited M1 polarization and suppressed these inflammatory markers in THP-1 cells.
- M1 macrophage conditioned medium induced NP cell apoptosis and ECM degradation; MAG treatment reversed these detrimental effects, reducing HMGB1 and inactivating the MyD88/NF-κB and NLRP3 pathways.
Conclusions:
- Magnoflorine (MAG) effectively alleviates M1 macrophage-mediated NP cell damage in intervertebral disc degeneration.
- MAG exerts its protective effects by inhibiting the HMGB1-MyD88-NF-κB pathway and NLRP3 inflammasome activation.
- MAG represents a potential therapeutic agent for treating IDD by modulating macrophage polarization and inflammation.
