Distinct Effect of TCF4 on the NFκB Pathway in Human Primary Chondrocytes and the C20/A4 Chondrocyte Cell Line

Objective: Previous studies indicated a difference in crosstalk between canonical WNT pathway and nuclear factor-κB (NFκB) signaling in human and animal chondrocytes. To assess whether the differences found were dependent on cell types used, we tested the effect of WNT modulation on NFκB signaling in human primary articular chondrocytes in comparison with the immortalized human costal chondrocyte cell line C20/A4. Design: We used gene expression analysis to study the effect of WNT modulation on IL1β-induced matrix metalloproteinase (MMP) expression as well as on WNT and NFκB target gene expression. In addition, we tested the involvement of RelA and TCF4 on activation of the WNT and NFκB pathway by TCF/LEF and NFκB reporter experiments, respectively. Results: We found an inhibitory effect of both induction and inhibition of WNT signaling on IL1β-induced MMP mRNA expression in primary chondrocytes, whereas WNT modulation did not affect MMP expression in C20/A4 cells. Furthermore, TCF/LEF and NFκB reporter activation and WNT and NFκB target gene expression were regulated differentially by TCF4 and RelA in a cell type–dependent manner. Additionally, we found significantly higher mRNA and protein expression of TCF4 and RelA in C20/A4 cells in comparison with primary chondrocytes. Conclusions: We conclude that WNT modulation of NFκB is, at least in part, cell type dependent and that the observed differences are likely because of impaired sensitivity of the NFκB pathway in C20/A4 cells to modulations in WNT signaling. This might be caused by higher basal levels of TCF4 and RelA in C20/A4 cells compared to primary chondrocytes

Nanoparticle system for the local delivery of disease modifying osteoarthritic drugs

Purpose: The purpose of this study is to develop the nanoparticles that i) can be injected intra-articularly ii) target to cartilage due to an opposite charge difference with the extracellular cartilaginous matrix and iii) due to their small size can penetrate into the cartilage. In this way retention time in the joint can be prolonged. By releasing disease modifying OA drugs (DMOAD) in the vicinity of chondrocytes such materials may be beneficial for restoring cartilage tissue homeostasis. Here we demonstrate the generation of drug-containing nanoparticles for intra-articular joint therapy. Methods: We have prepared nanoparticles of biodegradable poly ethylene glycol- poly lactic acid PEG-PLA co-block polymers. The hydrophilic PEG and hydrophobic PLA ends of this polymer make it possible to generate micelles that contain drugs. The polymers are functionalized with UV-sensitive acrylate groups that can be stabilized by UV-crosslinking. These drug containing nanoparticles will be used for intra-articular joint injection and release of DMOADs. We have also established co-culture systems in vitro using MSCs and chondrocytes where the effect of these molecules and nanocarriers can be tested. Results: Micelle type nanoparticles using PEG-PLA co-block polymers were prepared. The obtained dexamethasone loaded nanoparticles had diameters of 20-80 nm. These nanoparticles are photo-crosslinked at their hydrophobic cores which provides stability to the structure and resulted in a slight decrease in average particle size . Dexamethasone was successfully encapsulated in these nanoparticles. The current release profiles show initial burst release in the first 8 hours followed by a sustained release over at least 3 days. Conclusions: We have generated nanoparticles that can serve as a carrier system to deliver clinically relevant disease modifying osteoarthritic drugs in a more effective way after intra-articular injection. We are currently investigating the retention of nanoparticles in the joint and are developing strategies to target these particles to cartilag

Distinct Effect of TCF4 on the NFκB Pathway in Human Primary Chondrocytes and the C20/A4 Chondrocyte Cell Line

Objective: Previous studies indicated a difference in crosstalk between canonical WNT pathway and nuclear factor-κB (NFκB) signaling in human and animal chondrocytes. To assess whether the differences found were dependent on cell types used, we tested the effect of WNT modulation on NFκB signaling in human primary articular chondrocytes in comparison with the immortalized human costal chondrocyte cell line C20/A4. Design: We used gene expression analysis to study the effect of WNT modulation on IL1β-induced matrix metalloproteinase (MMP) expression as well as on WNT and NFκB target gene expression. In addition, we tested the involvement of RelA and TCF4 on activation of the WNT and NFκB pathway by TCF/LEF and NFκB reporter experiments, respectively. Results: We found an inhibitory effect of both induction and inhibition of WNT signaling on IL1β-induced MMP mRNA expression in primary chondrocytes, whereas WNT modulation did not affect MMP expression in C20/A4 cells. Furthermore, TCF/LEF and NFκB reporter activation and WNT and NFκB target gene expression were regulated differentially by TCF4 and RelA in a cell type–dependent manner. Additionally, we found significantly higher mRNA and protein expression of TCF4 and RelA in C20/A4 cells in comparison with primary chondrocytes. Conclusions: We conclude that WNT modulation of NFκB is, at least in part, cell type dependent and that the observed differences are likely because of impaired sensitivity of the NFκB pathway in C20/A4 cells to modulations in WNT signaling. This might be caused by higher basal levels of TCF4 and RelA in C20/A4 cells compared to primary chondrocytes

Nanoparticle system for the local delivery of disease modifying osteoarthritic drugs

Purpose: The purpose of this study is to develop the nanoparticles that i) can be injected intra-articularly ii) target to cartilage due to an opposite charge difference with the extracellular cartilaginous matrix and iii) due to their small size can penetrate into the cartilage. In this way retention time in the joint can be prolonged. By releasing disease modifying OA drugs (DMOAD) in the vicinity of chondrocytes such materials may be beneficial for restoring cartilage tissue homeostasis. Here we demonstrate the generation of drug-containing nanoparticles for intra-articular joint therapy. Methods: We have prepared nanoparticles of biodegradable poly ethylene glycol- poly lactic acid PEG-PLA co-block polymers. The hydrophilic PEG and hydrophobic PLA ends of this polymer make it possible to generate micelles that contain drugs. The polymers are functionalized with UV-sensitive acrylate groups that can be stabilized by UV-crosslinking. These drug containing nanoparticles will be used for intra-articular joint injection and release of DMOADs. We have also established co-culture systems in vitro using MSCs and chondrocytes where the effect of these molecules and nanocarriers can be tested. Results: Micelle type nanoparticles using PEG-PLA co-block polymers were prepared. The obtained dexamethasone loaded nanoparticles had diameters of 20-80 nm. These nanoparticles are photo-crosslinked at their hydrophobic cores which provides stability to the structure and resulted in a slight decrease in average particle size . Dexamethasone was successfully encapsulated in these nanoparticles. The current release profiles show initial burst release in the first 8 hours followed by a sustained release over at least 3 days. Conclusions: We have generated nanoparticles that can serve as a carrier system to deliver clinically relevant disease modifying osteoarthritic drugs in a more effective way after intra-articular injection. We are currently investigating the retention of nanoparticles in the joint and are developing strategies to target these particles to cartilag

Nanomaterials for the Local and Targeted Delivery of Osteoarthritis Drugs

Abstract Nanotechnology has found its potential in every possible field of science and engineering. It offers a plethora of options to design tools at the nanometer scale, which can be expected to function more effectively than micro- and macrosystems for specific applications. Although the debate regarding the safety of synthetic nanomaterials for clinical applications endures, it is a promising technology due to its potential to augment current treatments. Various materials such as synthetic polymer, biopolymers, or naturally occurring materials such as proteins and peptides can serve as building blocks for adaptive nanoscale formulations. The choice of materials depends highly on the application. We focus on the use of nanoparticles for the treatment of degenerative cartilage diseases, such as osteoarthritis (OA). Current therapies for OA focus on treating the symptoms rather than modifying the disease. The usefulness of OA disease modifying drugs is hampered by side effects and lack of suitable drug delivery systems that target, deliver, and retain drugs locally. This challenge can be overcome by using nanotechnological formulations. We describe the different nanodrug delivery systems and their potential for cartilage repair. This paper provides the reader basal understanding of nanomaterials and aims at drawing new perspectives on the use of existing nanotechnological formulations for the treatment of osteoarthritis