Proteoglycan-4 Regulates Fibroblast to Myofibroblast Transition and Expression of Fibrotic Genes in the Synovium

Background: Synovial tissue fibrosis is common in advanced OA with features including the presence of stress fiber-positive myofibroblasts and deposition of cross-linked collagen type-I. Proteoglycan-4 (PRG4) is a mucinous glycoprotein secreted by synovial fibroblasts and is a major component of synovial fluid. PRG4 is a ligand of the CD44 receptor. Our objective was to examine the role of PRG4-CD44 interaction in regulating synovial tissue fibrosis in vitro and in vivo. Methods: OA synoviocytes were treated with TGF-β ± PRG4 for 24h and α-SMA content was determined using immunofluorescence. Rhodamine-labeled rhPRG4 was incubated with OA synoviocytes ± anti-CD44 or isotype control antibodies and cellular uptake of rhPRG4 was determined following a 30-min incubation and α-SMA expression following a 24-h incubation. HEK-TGF-β cells were treated with TGF-β ± rhPRG4 and Smad3 phosphorylation was determined using immunofluorescence and TGF-β/Smad pathway activation was determined colorimetrically. We probed for stress fibers and focal adhesions (FAs) in TGF-β-treated murine fibroblasts and fibroblast migration was quantified ± rhPRG4. Synovial expression of fibrotic markers: α-SMA, collagen type-I, and PLOD2 in Prg4 gene-trap (Prg4GT) and recombined Prg4GTR animals were studied at 2 and 9 months of age. Synovial expression of α-SMA and PLOD2 was determined in 2-month-old Prg4GT/GT&Cd44−/− and Prg4GTR/GTR&Cd44−/− animals. Results: PRG4 reduced α-SMA content in OA synoviocytes (p \u3c 0.001). rhPRG4 was internalized by OA synoviocytes via CD44 and CD44 neutralization attenuated rhPRG4’s antifibrotic effect (p \u3c 0.05). rhPRG4 reduced pSmad3 signal in HEKTGF- β cells (p \u3c 0.001) and TGF-β/Smad pathway activation (p \u3c 0.001). rhPRG4 reduced the number of stress fiberpositive myofibroblasts, FAs mean size, and cell migration in TGF-β-treated NIH3T3 fibroblasts (p \u3c 0.05). rhPRG4 inhibited fibroblast migration in a macrophage and fibroblast co-culture model without altering active or total TGF-β levels. Synovial tissues of 9-month-old Prg4GT/GT animals had higher α-SMA, collagen type-I, and PLOD2 (p \u3c 0.001) content and Prg4 re-expression reduced these markers (p \u3c 0.01). Prg4 re-expression also reduced α-SMA and PLOD2 staining in CD44-deficient mice. Conclusion: PRG4 is an endogenous antifibrotic modulator in the joint and its effect on myofibroblast formation is partially mediated by CD44, but CD44 is not required to demonstrate an antifibrotic effect in vivo

New developments in osteoarthritis. Posttraumatic osteoarthritis: pathogenesis and pharmacological treatment options

Joint trauma can lead to a spectrum of acute lesions, including osteochondral fractures, ligament or meniscus tears and damage to the articular cartilage. This is often associated with intraarticular bleeding and causes posttraumatic joint inflammation. Although the acute symptoms resolve and some of the lesions can be surgically repaired, joint injury triggers a chronic remodeling process in cartilage and other joint tissues that ultimately manifests as osteoarthritis in a majority of cases. The objective of the present review is to summarize information on pathogenetic mechanisms involved in the acute and chronic consequences of joint trauma and discuss potential pharmacological interventions. The focus of the review is on the early events that follow joint trauma since therapies for posttraumatic joint inflammation are not available and this represents a unique window of opportunity to limit chronic consequences

Chemotherapy e-prescribing: opportunities and challenges

Khaled A Elsaid,1,2 Steven Garguilo,1 Christine M Collins2 1Department of Pharmaceutical Sciences, School of Pharmacy, MCPHS University, Boston, MA, 2Pharmacy Services, Rhode Island Hospital, Providence, RI, USA Abstract: Chemotherapy drugs are characterized by low therapeutic indices and significant toxicities at clinically prescribed doses, raising serious issues of drug safety. The safety of the chemotherapy medication use process is further challenged by regimen complexity and need to tailor treatment to patient status. Errors that occur during chemotherapy prescribing are associated with serious and life-threatening outcomes. Computerized provider order entry (CPOE) systems were shown to reduce overall medication errors in ambulatory and inpatient settings. The adoption of chemotherapy CPOE is lagging due to financial cost and cultural and technological challenges. Institutions that adopted infusional or oral chemotherapy electronic prescribing modified existing CPOE systems to allow chemotherapy prescribing, implemented chemotherapy-specific CPOE systems, or developed home-grown chemotherapy electronic prescribing programs. Implementation of chemotherapy electronic prescribing was associated with a significant reduction in the risk of prescribing errors, most significantly dose calculation and adjustment errors. In certain cases, implementation of chemotherapy CPOE was shown to improve the chemotherapy use process. The implementation of chemotherapy CPOE may increase the risk of new types of errors, especially if processes are not redesigned and adapted to CPOE. Organizations aiming to implement chemotherapy CPOE should pursue a multidisciplinary approach engaging all stakeholders to guide system selection and implementation. Following implementation, organizations should develop and use a risk assessment process to identify and evaluate unanticipated consequences and CPOE-generated errors. The results of these analyses should serve to further enhance the chemotherapy electronic prescribing process and improve the quality and safety of cancer care. Keywords: computerized provider order entry, electronic health records, chemotherap

Pattern of headache in school children in the State of Qatar

Objectives: The aim of this study is to determine the prevalence rate and impact of headache in school children on school attendance with particular attention to migraine

Cathepsin g Degrades Both Glycosylated and Unglycosylated Regions of Lubricin, a Synovial Mucin

Lubricin (PRG4) is a mucin type protein that plays an important role in maintaining normal joint function by providing lubrication and chondroprotection. Improper lubricin modification and degradation has been observed in idiopathic osteoarthritis (OA), while the detailed mechanism still remains unknown. We hypothesized that the protease cathepsin G (CG) may participate in degrading lubricin in synovial fluid (SF). The presence of endogenous CG in SF was confirmed in 16 patients with knee OA. Recombinant human lubricin (rhPRG4) and native lubricin purified from the SF of patients were incubated with exogenous CG and lubricin degradation was monitored using western blot, staining by Coomassie or Periodic Acid-Schiff base in gels, and with proteomics. Full length lubricin (∼300 kDa), was efficiently digested with CG generating a 25-kDa protein fragment, originating from the densely glycosylated mucin domain (∼250 kDa). The 25-kDa fragment was present in the SF from OA patients, and the amount was increased after incubation with CG. A CG digest of rhPRG4 revealed 135 peptides and 72 glycopeptides, and confirmed that the protease could cleave in all domains of lubricin, including the mucin domain. Our results suggest that synovial CG may take part in the degradation of lubricin, which could affect the pathological decrease of the lubrication in degenerative joint disease