Effect of budesonide on fibroblast-mediated collagen gel contraction and degradation

Qiuhong Fang,^1,2 Nancy A Schulte,³ Huijung Kim,⁴ Tetsu Kobayashi,⁵ Xingqi Wang,² Anna Miller-Larsson,⁶ Elisabet Wieslander,⁶ Myron L Toews,³ Xiangde Liu,² Stephen I Rennard<sup>2

1</sup>Pulmonary and Critical Care Department, Beijing Shijitan Hospital, Capital Medical University, Beijing, People's Republic of China; ²Pulmonary, Critical Care, Sleep and Allergy Division, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA; ³Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA; ⁴Pulmonary and Critical Care Division, WonKwang University, Kunpo Medical Center, Seoul, Republic of Korea; ⁵Mie University Graduate School of Medicine, Tsu City, Japan; ⁶AstraZeneca R&D Molndal, Molndal, Sweden

Background: The balance between production and degradation of extracellular matrix is crucial in maintaining normal tissue structure. This study was designed to investigate the effect of budesonide on fibroblast-mediated tissue repair and remodeling.
Methods: Using human fetal lung fibroblasts in a three-dimensional collagen gel culture system, we investigated the effect of budesonide (1–1000 nM) on collagen gel contraction and degradation in the presence or absence of inflammatory cytokines (interleukin-1β and tumor necrosis factor α; 5 ng/mL each) and, in order to activate latent proteases, serine protease trypsin 0.25 µg/mL. The effects of budesonide on metalloproteinase production and activation were also investigated.
Results: Inflammatory cytokines significantly inhibited collagen gel contraction mediated by lung fibroblasts. Budesonide counteracted the effect of cytokines in a concentration-dependent manner (to 50%, P < 0.01). Budesonide 100 nM almost completely inhibited the release and mRNA expression of metalloproteinase-1, metalloproteinase-3, and metalloproteinase-9 induced by the cytokines (P < 0.05). Exposure to the cytokines plus trypsin increased collagen degradation and conversion of the metalloproteinases to lower molecular weight forms corresponding to their active forms. Budesonide blocked both enhanced collagen degradation (P < 0.01) and suppressed trypsin-mediated conversion of cytokine-induced metalloproteinase-9 and metalloproteinase-3 to lower molecular weight forms. Similar effects were observed with dexamethasone 1 µM, suggesting a class effect.
Conclusion: These findings demonstrate that budesonide directly modulates contraction of collagen gels and can decrease collagen degradation under inflammatory conditions. The mechanism of this effect is through suppressing gene expression, release, and activation of metalloproteinases. By modulating the release and activity of metalloproteinases, inhaled budesonide may be able to modify airway tissue repair and remodeling.

Keywords: metalloproteinase, budesonide, tissue remodeling