Syndecan-4 regulates early neutrophil migration and pulmonary inflammation in response to lipopolysaccharide.

Department of Pulmonary Medicine, Fukushima Medical University School of Medicine, Japan.
American Journal of Respiratory Cell and Molecular Biology (Impact Factor: 4.11). 03/2012; 47(2):196-202. DOI: 10.1165/rcmb.2011-0294OC
Source: PubMed

ABSTRACT Proteoglycans (PGs) and their associated glycosaminoglycan side chains are effectors of inflammation, but little is known about changes to the composition of PGs in response to lung infection or injury. The goals of this study were to identify changes to heparan sulfate PGs in a mouse model of gram-negative pneumonia, to identify the Toll-like receptor adaptor molecules responsible for these changes, and to determine the role of the heparan sulfate PG in the innate immune response in the lungs. We treated mice with intratracheal LPS, a component of the cell wall of gram-negative bacteria, to model gram-negative pneumonia. Mice treated with intratracheal LPS had a rapid and selective increase in syndecan-4 mRNA that was regulated through MyD88-dependent mechanisms, whereas expression of several other PGs was not affected. To determine the role of syndecan-4 in the inflammatory response, we exposed mice deficient in syndecan-4 to LPS and found a significant increase in neutrophil numbers and amounts of CXC-chemokines and total protein in bronchoalveolar lavage fluid. In studies performed in vitro, macrophages and epithelial cells treated with LPS had increased expression of syndecan-4. Studies performed using BEAS-2B cells showed that pretreatment with heparin and syndecan-4 decreased the expression of CXCL8 mRNA in response to LPS and TNF-α. These findings indicate that the early inflammatory response to LPS involves marked up-regulation of syndecan-4, which functions to limit the extent of pulmonary inflammation and lung injury.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: Syndecans are heparan sulphate proteoglycans expressed by endothelial cells. Syndecan-3 is expressed by synovial endothelial cells of rheumatoid arthritis (RA) patients where it binds chemokines, suggesting a role in leukocyte trafficking. The objective of the current study was to examine the function of syndecan-3 in joint inflammation by genetic deletion in mice and compare with other tissues. Methods: Chemokine C-X-C ligand 1 (CXCL1) was injected in the joints of syndecan-3-/-and wild-type mice and antigen-induced arthritis performed. For comparison chemokine was administered in the skin and cremaster muscle. Intravital microscopy was performed in the cremaster muscle. Results: Administration of CXCL1 in knee joints of syndecan-3-/-mice resulted in reduced neutrophil accumulation compared to wild type. This was associated with diminished presence of CXCL1 at the luminal surface of synovial endothelial cells where this chemokine clustered and bound to heparan sulphate. Furthermore, in the arthritis model syndecan-3 deletion led to reduced joint swelling, leukocyte accumulation, cartilage degradation and overall disease severity. Conversely, CXCL1 administration in the skin of syndecan-3 null mice provoked increased neutrophil recruitment and was associated with elevated luminal expression of E-selectin by dermal endothelial cells. Similarly in the cremaster, intravital microscopy showed increased numbers of leukocytes adhering and rolling in venules in syndecan-3-/-mice in response to CXCL1 or tumour necrosis factor alpha. Conclusions: This study shows a novel role for syndecan-3 in inflammation. In the joint it is selectively pro-inflammatory, functioning in endothelial chemokine presentation and leukocyte recruitment and cartilage damage in an RA model. Conversely, in skin and cremaster it is anti-inflammatory.
    Arthritis Research & Therapy 07/2014; 16(4):R148. DOI:10.1186/ar4610 · 4.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the 25 years, as the first of the syndecan family was cloned, interest in these transmembrane proteoglycans has steadily increased. While four distinct members are present in mammals, one is present in invertebrates, including C. elegans that is such a powerful genetic model. The syndecans, therefore, have a long evolutionary history, indicative of important roles. However, these roles have been elusive. The knockout in the worm has a developmental neuronal phenotype, while knockouts of the syndecans in the mouse are mild and mostly limited to post-natal rather than developmental effects. Moreover, their association with high-affinity receptors, such as integrins, growth factor receptors, frizzled and slit/robo, have led to the notion that syndecans are coreceptors, with minor roles. Given that their heparan sulphate chains can gather many different protein ligands, this gave credence to views that the importance of syndecans lay with their ability to concentrate ligands and that only the extracellular polysaccharide was of significance. Syndecans are increasingly identified with roles in the pathogenesis of many diseases, including tumour progression, vascular disease, arthritis and inflammation. This has provided impetus to understanding syndecan roles in more detail. It emerges that while the cytoplasmic domains of syndecans are small, they have clear interactive capabilities, most notably with the actin cytoskeleton. Moreover, through the binding and activation of signalling molecules, it is likely that syndecans are important receptors in their own right. Here, an overview of syndecan structure and function is provided, with some prospects for the future.
    International Journal of Experimental Pathology 12/2014; 96(1). DOI:10.1111/iep.12112 · 2.05 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Secretoglobin (SCGB) 3A2, previously known as uteroglobin-related protein 1, is a secreted protein highly expressed in the epithelial cells of the airways. It has been demonstrated that SCGB3A2 is involved in allergic airway inflammation such as bronchial asthma. However, the role of SCGB3A2 in lipopolysaccharide (LPS)-induced airway inflammation has yet to be reported. The goal of this study was therefore to clarify the role of SCGB3A2 in LPS-induced airway inflammation. We stimulated BEAS-2B, human bronchial epithelial cells, with LPS and analyzed messenger RNA (mRNA) expression of tumor necrosis factor (TNF)-α and CXCL8 with or without pre-incubation of SCGB3A2. The mRNA expression of TNF-α and CXCL8 was clearly upregulated 3 h after LPS stimulation, and pre-incubation of SCGB3A2 significantly inhibited the upregulation of the mRNA expression. The pre-incubation of SCGB3A2 also inhibited LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but not p38 mitogen-activated protein kinase in BEAS-2B cells. Furthermore, PD98059, a specific inhibitor for ERK, as well as SP600125, a specific inhibitor for JNK, inhibited LPS-induced mRNA upregulation of inflammatory mediators. These results demonstrate the novel biological activity of SCGB3A2, which is that it attenuates LPS-induced inflammation in bronchial epithelial cells through inhibition of ERK and JNK activation.
    Inflammation 08/2014; 38(2). DOI:10.1007/s10753-014-9992-0 · 1.92 Impact Factor


Available from
May 22, 2014