ABSTRACT
AIM:To explore a novel method to isolate human nucleus pulposus mesenchymal stem cells (hNP-MSCs) in vitro and to identify their biological characteristics.METHODS:The explant culture method was employed to isolate hNP-MSCs from nucleus pulposus tissue obtained by percutaneous endoscopic lumbar discectomy (PELD).The isolated cells were passaged for purification and cultured in vitro followed by morphological observation.The cell proliferation ability was detected by CCK-8 assay.Growth curves of the cells were drawn and surface antigens were detected by flow cytometry.The cells at the 3rd~6th passages were induced for adipogenic, osteogenic and chondrogenic differentiation, and examined by oil red O staining, alizarin red staining and Alcian blue staining.RESULTS:The cells with self-renewal were obtained from nucleus pulposus tissue obtained by PELD.The results of flow cytometry analysis revealed that the cells were positive for CD29, CD44, CD90, CD73 and CD105, but negative for CD34 and CD45.The proliferative capacity was consistent with the growth characteristics of MSCs and multilineage differentiation potential was identified.CONCLUSION:A novel method to efficiently isolate and culture hNP-MSCs,PELD combined with explant culture method,was established, which would promote the study of regenerative medicine based on hNP-MSCs.
ABSTRACT
This study aims to explore the effect of microRNA-21 (miR-21) on the proliferation of human degenerated nucleus pulposus (NP) by targeting programmed cell death 4 (PDCD4) tumor suppressor. NP tissues were collected from 20 intervertebral disc degeneration (IDD) patients, and from 5 patients with traumatic spine fracture. MiR-21 expressions were tested. NP cells from IDD patients were collected and divided into blank control group, negative control group (transfected with miR-21 negative sequences), miR-21 inhibitor group (transfected with miR-21 inhibitors), miR-21 mimics group (transfected with miR-21 mimics) and PDCD4 siRNA group (transfected with PDCD4 siRNAs). Cell growth was estimated by Cell Counting Kit-8; PDCD4, MMP-2,MMP-9 mRNA expressions were evaluated by qRT-PCR; PDCD4, c-Jun and p-c-Jun expressions were tested using western blot. In IDD patients, the expressions of miR-21 and PDCD4 mRNA were respectively elevated and decreased (both P<0.05). The miR-21 expressions were positively correlated with Pfirrmann grades, but negatively correlated with PDCD4 mRNA (both P<0.001). In miR-21 inhibitor group, cell growth, MMP-2 and MMP-9 mRNA expressions, and p-c-Jun protein expressions were significantly lower, while PDCD4 mRNA and protein expressions were higher than the other groups (all P<0.05). These expressions in the PDCD4 siRNA and miR-21 mimics groups was inverted compared to that in the miR-21 inhibitor group (all P<0.05). MiR-21 could promote the proliferation of human degenerated NP cells by targeting PDCD4, increasing phosphorylation of c-Jun protein, and activating AP-1-dependent transcription of MMPs, indicating that miR-21 may be a crucial biomarker in the pathogenesis of IDD.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , RNA-Binding Proteins/metabolism , MicroRNAs/metabolism , Cell Proliferation/physiology , Apoptosis Regulatory Proteins/metabolism , Nucleus Pulposus/metabolism , Reference Values , Time Factors , Apoptosis Regulatory Proteins/analysisABSTRACT
PURPOSE: Human nucleus pulposus cells from intervertebral disc specimens were cultured to study the effects of TNF-alphaand IL-8 on the FAK expression by these cells. The effect of co-stimulation with dexamethasone on the FAK expression by nucleus pulposus cells was also studied. MATERIALS AND METHODS: The FAK expression in cultured human nucleus pulposus cells relation to TNF-alpha, IL-8 and dexamethasone was assessed by performing western blot. RESULTS: The activated FAK expression was up-regulated by treatments of TNF-alpha and IL-8. Dexamethasone attenuated the cytokine-induced FAK expression. The effects of inflammatory cytokines on the FAK expression were found to be concentration dependent with greater correlation shown by IL-8 than by TNF-alpha. CONCLUSION: The FAK expression of human nucleus pulposus cells was up-regulated by TNF-alpha and IL-8 stimulation and it was attenuated by the co-administration of dexamethasone.