Primary murine airway smooth muscle cells exposed to poly(I,C) or tunicamycin synthesize a leukocyte-adhesive hyaluronan matrix

J Biol Chem. 2009 Feb 20;284(8):5299-312. doi: 10.1074/jbc.M807965200. Epub 2008 Dec 16.

Abstract

Asthmatic attacks often follow viral infections with subsequent airway smooth muscle cell proliferation and the formation of an abnormal hyaluronan extracellular matrix with infiltrated leukocytes. In this study, we show that murine airway smooth muscle cells (MASM) treated with polyinosinic acid-polycytidylic acid (poly(I,C)), a double-stranded RNA that simulates a viral infection, synthesize an abnormal hyaluronan matrix that binds leukocytes (U937 cells). Synthesis of this matrix is initiated rapidly and accumulates linearly for approximately 10 h, reaching a plateau level approximately 7-fold higher than control cultures. MASM cells treated with tunicamycin, to induce endoplasmic reticulum stress, also rapidly initiate synthesis of the abnormal hyaluronan matrix with linear accumulation for approximately 10 h, but only reach a plateau level approximately 2-fold higher than control cultures. In contrast to poly(I,C), the response to tunicamycin depends on cell density, with pre-confluent cells producing more abnormal matrix per cell. Furthermore, U937 cell adhesion per hyaluronan content is higher in the sparse matrix produced in response to tunicamycin, suggesting that the structure in the poly(I,C)-induced matrix masks potential binding sites. When MASM cells were exposed to tunicamycin and poly(I,C) at the same time, U937 cell adhesion was partially additive, implying that these two toxins stimulate hyaluronan synthesis through two different pathways. We also characterized the size of hyaluronan produced by MASM cells, in response to poly(I,C) and tunicamycin, and we found that it ranges from 1500 to 4000 kDa, the majority of which was approximately 4000 kDa and not different in size than hyaluronan made by untreated cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antiviral Agents / pharmacology*
  • Asthma / immunology
  • Asthma / metabolism
  • Cell Adhesion / drug effects
  • Endoplasmic Reticulum / immunology
  • Endoplasmic Reticulum / metabolism
  • Extracellular Matrix / metabolism*
  • Female
  • Humans
  • Hyaluronic Acid / biosynthesis*
  • Hyaluronic Acid / immunology
  • Leukocytes / immunology
  • Leukocytes / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Myocytes, Smooth Muscle / immunology
  • Myocytes, Smooth Muscle / metabolism*
  • Poly I-C / pharmacology*
  • RNA, Double-Stranded / pharmacology
  • Respiratory System / immunology
  • Respiratory System / metabolism*
  • Tunicamycin / pharmacology*
  • U937 Cells

Substances

  • Antiviral Agents
  • RNA, Double-Stranded
  • Tunicamycin
  • Hyaluronic Acid
  • Poly I-C