Explore the vast range of titles available.

Tumor necrosis factor-alpha (TNFα), a pro-inflammatory cytokine, has been shown to play a role in the pathophysiology of rheumatoid arthritis. Silencing TNFα expression with small interfering RNA (siRNA) is a promising approach to treatment of the condition. Towards this end, our team has developed a modified chitosan (CH) nanocarrier, deploying folic acid, diethylethylamine (DEAE) and polyethylene glycol (PEG) (folate-PEG-CH-DEAE ). The gene carrier protects siRNA against nuclease destruction, its ligands facilitate siRNA uptake via cell surface receptors, and it provides improved solubility at neutral pH with transport of its load into target cells. In the present study, nanoparticles were prepared with siRNA-TNFα, DEAE, and folic acid-CH derivative. Nanoparticle size and zeta potential were verified by dynamic light scattering. Their TNFα-knockdown effects were tested in a murine collagen antibody-induced arthritis model. TNFα expression was examined along with measurements of various cartilage and bone turnover markers by performing histology and microcomputed tomography analysis. We demonstrated that folate-PEG-CH-DEAE /siRNA nanoparticles did not alter cell viability, and significantly decreased inflammation, as demonstrated by improved clinical scores and lower TNFα protein concentrations in target tissues. This siRNA nanocarrier also decreased articular cartilage destruction and bone loss. The results indicate that folate-PEG-CH-DEAE nanoparticles are a safe and effective platform for nonviral gene delivery of siRNA, and their potential clinical applications warrant further investigation.

Objective and design Resolvin D1 (RvD1), an omega-3 fatty acid derivative, has shown remarkable properties in resolving inflammation, promoting tissue repair and preserving tissue integrity. In this study, we investigated RvD1 effects on major processes involved in osteoarthritis (OA) pathophysiology. Materials and methods Human OA chondrocytes were treated with either 1 ng/ml interleukin-1β (IL-1β) or 20 μM 4-hydroxynonenal (HNE), then treated or not with increased concentrations of RvD1 (0–10 μM). RvD1 levels were measured by enzyme immunoassay in synovial fluids from experimental dog model of OA and sham operated dogs obtained from our previous study. Cell viability was evaluated by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-SH-tetrazolium bromide assay. Parameters related to inflammation, catabolism and apoptosis were determined by enzyme-linked immunosorbent assay, Western blotting, and quantitative polymerase chain reaction. Glutathione (GSH) was assessed by commercial kit. The activation of mitogen-activated protein kinases and nuclear factor-kappaB (NF-κB) pathways was evaluated by Western blot. Results We showed that RvD1 levels were higher in synovial fluids from OA joint compared to controls. In OA human chondrocytes, we demonstrated that RvD1 was not toxic up to 10 μM and stifled IL-1β-induced cyclooxygenase 2, prostaglandin E2, inducible nitric oxide synthase, nitric oxide, and matrix metalloproteinase-13. Our study of signalling pathways revealed that RvD1 suppressed IL-1β-induced activation of NF-κB/p65, p38/MAPK and JNK 1/2 . Moreover, RvD1 prevented HNE-induced cell apoptosis and oxidative stress, as indicated by inactivation of caspases, inhibition of lactate dehydrogenase release, and increased levels of Bcl2 and AKT, as well as GSH. Conclusion This is the first in vitro study demonstrating the beneficial effect of RvD1 in OA. That RvD1 abolishing a number of factors known to be involved in OA pathogenesis renders it a clinically valuable agent in prevention of the disease.

Background Over the years, many theories have been proposed and examined to better explain the etiology and development of osteoarthritis (OA). The characteristics of joint destruction are one of the most important aspects in disease progression. Therefore, investigating different factors and signaling pathways involved in the alteration of extracellular matrix (ECM) turnover, and the subsequent catabolic damage to cartilage holds chief importance in understanding OA development. Among these factors, reactive oxygen species (ROS) have been at the forefront of the physiological and pathophysiological OA investigation. Findings In the last decades, research studies provided an enormous volume of data supporting the involvement of ROS in OA. Most interestingly, published data regarding the effect of exogenous antioxidant therapy in OA lack conclusive results from clinical trials to back up in vitro data. Accordingly, it is rational to suggest that there are other reactive species in OA that are not taken into account. Thus, our present review is focused on our current understanding of the involvement of lipid peroxidation-derived 4-hydroxynonenal (HNE) in OA. Conclusion Our findings, like those in the literature, illustrate the central role played by HNE in the regulation of a number of factors involved in joint homeostasis. HNE could thus be considered as an attractive therapeutic target in OA.

BackgroundResolvin-D1 (RvD1) is a derivative of omega-3 fatty acids and a potent anti-inflammatory agent synthesized during the resolution phase of inflammation. In human cartilage, we recently reported that RvD1 strongly inhibited a number of factors involved in inflammation, catabolism, oxidative stress, and apoptosis.ObjectivesThe overall objective of this study is to further investigate RvD1 effects on bone metabolism in vitro.MethodsFirst, murine macrophages RAW267.4 were used to assess osteoclasts (OC) recruitment and bone resorption. RAW264.7 cells were incubated with 50 ng/ml LPS with or without RvD1 (0 - 10 μM) for 48 hours. Cell viability was verified with the MTS test. OC phenotype markers, namely TRAP and cathepsin-K, were assessed by western blot, enzymatic staining and immunocytochemistry. Levels of TNF-α, IL-1β, IL-6, IL-10, were measured by ELISA, and PGE2 levels by EIA. NO release was measured by Greiss reaction.To investigate bone resorption, RAW264.7 cells were seeded in hydroxyapatite plates, then treated with 50 ng/ml LPS with or without RvD1 (0.5 and 1 μ M) for 48 hours. Plot formation was assessed by Von Kossa staining.Second, human osteoblasts (Ob) were obtained from post-surgery discarded trabecular bone of osteoarthritic (OA) patients who underwent total knee arthroplasty. First passage human OA Ob were treated either with RvD1 (0.1 - 1 μM) alone, or with 20 nM VitD3 with or without RvD1 (0.1 - 1 μ M), for 48 hours. Cell viability was evaluated with the MTS test. Alkaline phosphatase (PAL) activity and osteocalcin (OCN) release was determined by colorimetric reaction and ELISA, respectively.ResultsIn RAW264.7 cells, our results clearly show that RvD1 strongly reduces OC recruitment and activation as indicated by the inhibition of TRAP and cathepsin K expression as well as TNF-α, IL-1β, IL-6, PGE2 and NO release, as well as the concurrent enhancement of IL-10 levels. Besides, RvD1 decreases bone resorption through the inhibition of plots formation in hydroxyapatite matrix. In human OA Ob, RvD1 partially decreases VitD3-induced PAL activity, while it maintains OCN expression at control levels.ConclusionsOur in vitro results clearly show that RvD1 may play an important role in the regulation of bone metabolism. Additionally to our previous data, our findings suggest that RvD1 may offer a novel and original perspective to make a real contribution to musculoskeletal and bone diseases therapy.AcknowledgementsThis study was supported by Canadian Institute of Health Research (CIHR) grant (#IMH 131570) and by the Center of Excellence for Arthroplasty Research.Disclosure of InterestNone declared

Background: Tumor necrosis factor-alpha (TNF[alpha]), a pro-inflammatory cytokine, has been shown to play a role in the pathophysiology of rheumatoid arthritis. Silencing TNF[alpha] expression with small interfering RNA (siRNA) is a promising approach to treatment of the condition. Methods: Towards this end, our team has developed a modified chitosan (CH) nanocarrier, deploying folic acid, diethylethylamine (DEAE) and polyethylene glycol (PEG) (folate-PEG-CH-[DEAE.sub.15]). The gene carrier protects siRNA against nuclease destruction, its ligands facilitate siRNA uptake via cell surface receptors, and it provides improved solubility at neutral pH with transport of its load into target cells. In the present study, nanoparticles were prepared with siRNA-TNF[alpha], DEAE, and folic acid-CH derivative. Nanoparticle size and zeta potential were verified by dynamic light scattering. Their TNF[alpha]-knockdown effects were tested in a murine collagen antibody-induced arthritis model. TNF[alpha] expression was examined along with measurements of various cartilage and bone turnover markers by performing histology and microcomputed tomography analysis. Results: We demonstrated that folate-PEG-CH-[DEAE.sub.15]/siRNA nanoparticles did not alter cell viability, and significantly decreased inflammation, as demonstrated by improved clinical scores and lower TNF[alpha] protein concentrations in target tissues. This siRNA nanocarrier also decreased articular cartilage destruction and bone loss. Conclusion: The results indicate that folate-PEG-CH-[DEAE.sub.15] nanoparticles are a safe and effective platform for nonviral gene delivery of siRNA, and their potential clinical applications warrant further investigation. Keywords: arthritis, inflammation, siRNA, TNF[alpha], nanoparticles, chitosan