Bleomycin induces fibrotic transformation of bone marrow stromal cells to treat height loss of intervertebral disc through the TGFβR1/Smad2/3 pathway

Abstract

Background: Lower back pain is often accredited to loss of intervertebral disc (IVD) height and compromised spine stability as a result of intervertebral disc degeneration (IVDD). We aim to locally use Bleomycin to induce the fibrotic transformation of bone marrow stromal cells (BMSCs) as a means to induce reparative fibrosis to slow down the height loss. Methods: IVD from patients were gathered for histological examination. The expression of transforming growth factor beta 1 (TGF-β) signaling pathway was determined by qPCR and western blotting. Nucleus pulposus (NP) cells, annulus fibrosus (AF) cells and the Rats’ bone marrow stromal cells (BMSC)were cultured and their responsiveness to Bleomycin was evaluated by Cell Counting Kit-8, comet assay, transwell migration and wound healing assays. Rat IVDD models were created by puncture, rescued by Bleomycin injection and the effectiveness was evaluated by images (X-ray and MRI) and atomic force microscope. Results: Histological examination showed increased levels of pro-fibrotic markers in IVDD tissues from patients. AF cells and BMSC cells was induced to adopt to a pro-fibrotic phenotype with increased expression fibrotic markers Col1a1, Col3a1, FSP1. The pro-fibrotic effect of Bleomycin on AF cells and BMSCs was in part due to the activation of the TGFβ-TGFβR1-SMAD2/3 signaling pathway. Pharmacological inhibition or gene knock-down of TGFβR1 could mitigate the pro-fibrotic effects. Conclusion: Locally injection of Bleomycin in rats’ IVD induced rapid fibrosis and maintained its height through TGFβ-TGFβR1-SMAD2/3 signaling pathway.

The P2X7 purinergic receptor in intervertebral disc degeneration

“…This means that an intrinsic repair response to tissue damage is possible, even if an actual healing process fails in most cases. These progenitor cells have also been attributed the ability to produce nondetrimental fibrotic changes as an initial compensatory protective mechanism to preserve the IVD height, through the formation of organized scar tissue necessary for mechanical stability (Chen et al, 2020;Frapin et al, 2020;Lyu et al, 2019;X. Yang et al, 2021).…”

“…This means that an intrinsic repair response to tissue damage is possible, even if an actual healing process fails in most cases. These progenitor cells have also been attributed the ability to produce nondetrimental fibrotic changes as an initial compensatory protective mechanism to preserve the IVD height, through the formation of organized scar tissue necessary for mechanical stability (Chen et al, 2020; Frapin et al, 2020; Lyu et al, 2019; X. Yang et al, 2021). It is reasonable to assume that P2X7R may support a reparative fibrosis process through two different ways: i. by the inflammasome‐mediated secretion of bioactive IL‐1β, which stimulates collagen expression and maintains high levels of active TGF‐β1 (Ouyang et al, 2013), the master regulator of fibrotic response (Lodyga et al, 2020); or ii.…”

Application of Bone Marrow Mesenchymal Stem Cells Effectively Eliminates Endotoxemia to Protect Rat from Acute Liver Failure Induced by Thioacetamide

“…The potential of BMSCs therapy largely depends on their migration, proliferation, and differentiation, regulated by multiple signaling pathways and factors, including the Wnt signal transduction pathway, oxidative stress, transforming growth factor beta (TGF-b) pathway, and phosphoinositide kinase-3 (PI3K)/protein kinase B (AKT) signal pathway [17][18][19][20]. Among them, the classical PI3K/ AKT signaling pathway is crucial, affecting the migration, proliferation, and intestinal differentiation of BMSCs [21].…”