A rapid increase in macrophage-derived versican and hyaluronan in infectious lung disease

Abstract

The goals of this study were to characterize the changes to chondroitin sulfate proteoglycans and hyaluronan in lungs in the acute response to gram-negative bacterial infection, and to identify cellular components responsible for these changes. Mice were treated with intratracheal (IT) live Escherichia coli, E. coli lipopolysaccharide (LPS), or PBS. Both E. coli and LPS caused rapid selective increases in mRNA expression of versican and hyaluronan synthase (Has) isoforms 1 and 2 associated with increased immunohistochemical and histochemical staining for versican and hyaluronan in the lungs. Versican was associated with a subset of alveolar macrophages. To examine whether macrophages contribute to versican and hyaluronan accumulation, in vitro studies with primary cultures of bone marrow-derived and alveolar macrophages were performed. Unstimulated macrophages expressed very low levels of versican and hyaluronan synthase mRNA, with no detectible versican protein or hyaluronan product. Stimulation with LPS caused rapid increases in versican mRNA and protein, a rapid increase in Has1 mRNA, and concomitant inhibition of hyaluronidases 1 and 2, the major hyaluronan degrading enzymes. Hyaluronan could be detected following chloroquine pre-treatment, indicating rapid turnover and degradation of hyaluronan by macrophages. In addition, the effects of LPS, the M1 macrophage classical activation agonist, were compared to those of IL-4/IL-13 or IL-10, the M2a and M2c alternative activation agonists, respectively. Versican and Has1 increased only in response to M1 activation. Finally, the up-regulation of versican and Has1 in the whole lungs of wild-type mice following IT LPS was completely abrogated in TLR-4−/− mice. These findings suggest that versican and hyaluronan synthesis may play an important role in the innate immune response to gram-negative lung infection.

Subepithelial Accumulation of Versican in a Cockroach Antigen-Induced Murine Model of Allergic Asthma

“…24,25 In addition, studies have confirmed that increases in versican expression influence cell adhesion, proliferation, migration, and survival as well as regulation of key inflammatory response. [26][27][28] Versican accumulation in the subepithelial layer in airways of atopic asthmatics has been described previously and correlates with the degree of AHR to methacholine challenge. 16 In addition, increased versican accumulation is associated with both small and large airway remodeling seen in autopsy specimens following fatal asthma exacerbations.…”

Correlation of Versican Expression, Accumulation, and Degradation during Embryonic Development by Quantitative Immunohistochemistry

“…Versican expression, typically present at low levels in most adult tissues, is increased in the lung during experimentally induced inflammation (Gill et al 2010;Chang et al 2014). In human lungs, versican accumulation is increased in many pathological conditions (Bensadoun et al 1996(Bensadoun et al , 1997Lowry et al 2008;Merrilees et al 2008;Gill et al 2010;Chang et al 2014;Wight et al 2014a). Versican expression in the CNS is also increased following injury and altered in diseases such as multiple sclerosis (Fawcett and Asher 1999;Schmalfeldt et al 2000;Sobel and Ahmed 2001;Asher et al 2002;Gu et al 2007).…”

“…Immunohistochemistry was performed as previously described (Fu et al 2011;Chang et al 2014). Briefly, all embryos were pretreated with Chondroitinase ABC for 1 hr and HIER1 (Citrate) for 10 min before combining with rabbit antimouse β-GAG antibody (#1033, lot #2006928; Millipore, Billerica, MA) for 1 hr at 2 µg/ml to detect for versican accumulation.…”

Versican Deficiency Significantly Reduces Lung Inflammatory Response Induced by Polyinosine-Polycytidylic Acid Stimulation

“…Versican expression, which is high in lungs during embryonic development (7-9) but low in adult lungs, is reactivated in numerous lung diseases, including pulmonary fibrosis, chronic obstructive pulmonary disease, acute respiratory distress syndrome, and asthma (10 -18). Our published work has shown that versican and molecules that associate with versican, such as HA, are the principal ECM components that accumulate in inflamed lungs at early times following exposure to pathogens, such as LPS (19). The accumulation of a versican-enriched ECM coincides with invasion and retention of leukocytes within different compartments of the lung during these early inflammatory responses.…”