Mélanie Welman

Perturbation of adhesion molecule-mediated chondrocyte-matrix interactions by 4-hydroxynonenal binding: implication in osteoarthritis pathogenesis

IntroductionObjectives were to investigate whether interactions between human osteoarthritic chondrocytes and 4-hydroxynonenal (HNE)-modified type II collagen (Col II) affect cell phenotype and functions and to determine the protective role of carnosine (CAR) treatment in preventing these effects.MethodsHuman Col II was treated with HNE at different molar ratios (MR) (1:20 to 1:200; Col II:HNE). Articular chondrocytes were seeded in HNE/Col II adduct-coated plates and incubated for 48 hours. Cell morphology was studied by phase-contrast and confocal microscopy. Adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and α1β1 integrin at protein and mRNA levels were quantified by Western blotting, flow cytometry and real-time reverse transcription-polymerase chain reaction. Cell death, caspases activity, prostaglandin E2 (PGE2), metalloproteinase-13 (MMP-13), mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) were assessed by commercial kits. Col II, cyclooxygenase-2 (COX-2), MAPK, NF-κB-p65 levels were analyzed by Western blotting. The formation of α1β1 integrin-focal adhesion kinase (FAK) complex was revealed by immunoprecipitation.ResultsCol II modification by HNE at MR approximately 1:20, strongly induced ICAM-1, α1β1 integrin and MMP-13 expression as well as extracellular signal-regulated kinases 1 and 2 (ERK1/2) and NF-κB-p65 phosphorylation without impacting cell adhesion and viability or Col II expression. However, Col II modification with HNE at MR approximately 1:200, altered chondrocyte adhesion by evoking cell death and caspase-3 activity. It inhibited α1β1 integrin and Col II expression as well as ERK1/2 and NF-κB-p65 phosphorylation, but, in contrast, markedly elicited PGE2 release, COX-2 expression and p38 MAPK phosphorylation. Immunoprecipitation assay revealed the involvement of FAK in cell-matrix interactions through the formation of α1β1 integrin-FAK complex. Moreover, the modification of Col II by HNE at a 1:20 or approximately 1:200 MR affects parameters of the cell shape. All these effects were prevented by CAR, an HNE-trapping drug.ConclusionsOur novel findings indicate that HNE-binding to Col II results in multiple abnormalities of chondrocyte phenotype and function, suggesting its contribution in osteoarthritis development. CAR was shown to be an efficient HNE-snaring agent capable of counteracting these outcomes.

Expression and Regulation of CCR1 by Airway Smooth Muscle Cells in Asthma

C-C chemokines such as CCL11, CCL5, and CCL3 are central mediators in the pathogenesis of asthma. They are mainly associated with the recruitment and the activation of specific inflammatory cells, such as eosinophils, lymphocytes, and neutrophils. It has recently been shown that they can also activate structural cells, such as airway smooth muscle and epithelial cells. The aims of this study were to examine the expression of the CCL3 receptor, CCR1, on human airway smooth muscle cells (ASMC) and to document the regulation of this receptor by cytokines involved in asthma pathogenesis. We first demonstrated that CCR1 mRNA is increased in the airways of asthmatic vs control subjects and showed for the first time that ASMC express CCR1 mRNA and protein, both in vitro and in vivo. Calcium mobilization by CCR1 ligands confirmed its functionality on ASMC. Stimulation of ASMC with TNF-α and, to a lesser extent, IFN-γ resulted in an up-regulation of CCR1 expression, which was totally suppressed by both dexamethasone or mithramycin. Taken together, our data suggest that CCR1 might be involved in the pathogenesis of asthma, through the activation of ASMC by its ligands.

Protective role against hydrogen peroxide and fibroblast stimulation via Ce-doped TiO2 nanostructured materials

BACKGROUND Cerium oxide (CeO2) and Ce-doped nanostructured materials (NMs) are being seen as innovative therapeutic tools due to their exceptional antioxidant effects; nevertheless their bio-applications are still in their infancy. METHODS TiO2, Ce-TiO2 and CeO2-TiO2 NMs were synthesized by a bottom-up microemulsion-mediated strategy and calcined during 7h at 650°C under air flux. The samples were compared to elucidate the physicochemical characteristics that determine cellular uptake, toxicity and the influence of redox balance between the Ce(3+)/Ce(4+) on the cytoprotective role against an exogenous ROS source: H2O2. Fibroblasts were selected as a cell model because of their participation in wound healing and fibrotic diseases. RESULTS Ce-TiO2 NM obtained via sol-gel reaction chemistry of metallic organic precursors exerts a real cytoprotective effect against H2O2 over fibroblast proliferation, while CeO2 pre-formed nanoparticles incorporated to TiO2 crystalline matrix lead to a harmful CeO2-TiO2 material. TiO2 was processed by the same pathways as Ce-TiO2 and CeO2-TiO2 NM but did not elicit any adverse or protective influence compared to controls. CONCLUSIONS It was found that the Ce atoms source and its concentration have a clear effect on materials physicochemical properties and its subsequent influence in the cellular response. It can induce a range of biological reactions that vary from cytotoxic to cytoprotective. GENERAL SIGNIFICANCE Even though there are still some unresolved issues and challenges, the unique physical and chemical properties of Ce-based NMs are fascinating and versatile resources for different biomedical applications.

Specific inhalation challenge with flour induced release of brain-derived neurotrophic factor in nasal fluid.

Neurotrophins may play a role in the pathophysiology of allergic occupational rhinitis (OR). We sought to investigate whether an immediate allergic reaction that induces nasal inflammation is also able to induce changes in levels of brain‐derived neurotrophic factor (BDNF) in nasal lavage (NAL) fluid from patients with allergic OR.

Effect of inhalation exposure to wheat flour on sputum levels of brain-derived neurotrophic factor.

These results reflect the characterization of pediatric tree sensitization, the most prevalent pediatric outdoor allergy, in a large cohort of children. Although these results reflect characteristics of our patients and may not be applicable to other patients in other regions, these results nonetheless illustrate several considerations in the approach to pediatric aeroallergen sensitization. In addition, because tree pollen season may be even longer for patients in other areas of the country compared with our cohort in the Northeast, it is likely that the significance of tree sensitization in children demonstrated here is generalizable to other areas of the country. Our results indicate that although outdoor sensitization is traditionally not expected or sought in younger children, tree sensitization may be present in a clinically significant fraction of children of all ages. With a notable prevalence (13.0%) in children younger than 4 years, the prevalence of tree pollen sensitivity approaches that of the most common indoor aeroallergen sensitivity by the age of 4 years.8 In our cohort, the tree allergen sensitization profile of children younger than 4 years (in whom maple tree sensitivity was most prevalent) was significantly different than children 4 years and older (in whom birch tree sensitivity was most prevalent). Moreover, the clinical relevance of these tree sensitivities in these children younger than 4 years was confirmed by reports of seasonal outdoor exacerbations of rhinitis or asthma symptoms in a large fraction of the children. In light of the important role for aeroallergen sensitivity in the pathogenesis of pediatric rhinitis and asthma,2,7 our results support consideration of performing SPTs to trees in children, including those younger than 4 years.9 Particular consideration for tree SPTs should be given to those children younger than 4 years who have a diagnosis of asthma, recurrent wheezing, or suspicious symptoms outdoors during tree pollen season.10 Ahmad R. Sedaghat, MD, PhD*,y,z William J. Sheehan, MDx Apinya Bharmanee, MDx Kendra Harrisx Wanda Phipatanakul, MD, MSx