Collagen I Induces Discoidin Domain Receptor (DDR) 1 Expression through DDR2 and a JAK2-ERK1/2-mediated Mechanism in Primary Human Lung Fibroblasts

Pedro A. Ruiz,Gabor Jarai

doi:10.1074/jbc.m110.143693

Abstract

Discoidin domain receptors (DDRs) DDR1 and DDR2 are receptor tyrosine kinases with the unique ability among receptor tyrosine kinases to respond to collagen. Several signaling molecules have been implicated in DDR signaling, including Shp-2, Src, and MAPK pathways, but a detailed understanding of these pathways and their transcriptional targets is still lacking. Similarly, the regulation of the expression of DDRs is poorly characterized with only a few inflammatory mediators, such as lipopolysaccharide and interleukin-1β identified as playing a role in DDR1 expression. DDRs have been reported to induce the expression of various genes including matrix metalloproteinases and bone morphogenetic proteins, but the regulatory mechanisms underlying DDR-induced gene expression remain to be determined. The aim of the present work was to elucidate the molecular mechanisms implicated in the expression of DDRs and to identify DDR-induced signaling pathways and target genes. Our data show that collagen I induces the expression of DDR1 in a dose- and time-dependent manner in primary human lung fibroblasts. Furthermore, activation of DDR2, JAK2, and ERK1/2 MAPK signaling pathways was essential for collagen I-induced DDR1 and matrix metalloproteinase 10 expression. Finally, inhibition of the ERK1/2 pathway abrogated DDR1 expression by blocking the recruitment of the transcription factor polyoma enhancer A-binding protein 3 to the DDR1 promoter. Our data provide new insights into the molecular mechanisms of collagen I-induced DDR1 expression and demonstrate an important role for ERK1/2 activation and the recruitment of polyoma enhancer-A binding protein 3 to the DDR1 promoter.

Highlights

Of the lung, kidney, mammary gland, and gastrointestinal tract, whereas DDR2 is primarily found in cells of mesenchymal origin, such as fibroblasts and smooth muscle cells [1, 2]
To identify which of the five DDR1 isoforms generated by alternative splicing was responsible for the observed response, we first determined which isoforms were expressed in normal human lung fibroblasts (NHLFs)
Our data show that collagen I induces the expression of DDR1 and MMP-10 through the activation of DDR2 and independently of integrins in a time and concentration-dependent manner in primary NHLFs

Summary

Introduction

Of the lung, kidney, mammary gland, and gastrointestinal tract, whereas DDR2 is primarily found in cells of mesenchymal origin, such as fibroblasts and smooth muscle cells [1, 2]. DDRs have been implicated in the expression of pro-inflammatory mediators and matrix-degrading enzymes and play an important role in processes such as migration, proliferation, extracellular matrix (ECM) remodeling and wound repair [2, 5,6,7]. Very little is known about the regulation of DDR expression, and so far, only a few inflammatory mediators including TNF-␣, IL-1␤, and LPS have been shown to increase DDR1 expression [22], but the regulatory mechanisms governing the expression of DDRs, in structural cells, remain to be elucidated. Studies with knock-out mice and human carcinoma cells have shown that DDR1 and DDR2 play a crucial role in the expression of MMP-1, MMP-2, MMP-9, and MMP-10 in fibroblasts [3, 7, 24, 25]. 5Ј-GCGTCTGTCTGCGGGTAGAG-3Ј 5Ј-CCCCAATGGCTCTGCCTA-3Ј 5Ј-GGCCAAACCCACCAACAC-3Ј 5Ј-CCCTTTGCTGGTAGCTGTCAA-3Ј 5Ј-GCAGGCTCCTCAGCAAGG-3Ј 5Ј-GTCCCCAATGGCTCTGGT-3Ј 5Ј-TGTTCCTGCTGCTGCCTATCTT-3Ј 5Ј-GCTATAGAAGAATCACCAGCAGCAA-3Ј 5Ј-CGTCTGTCCCAGGATGACATC-3Ј 5Ј-TGGGCAGATTCCAAACCTTT-3Ј 5Ј-TCACAGAGCTCGCCCAGTT-3Ј 5Ј-GCCAGCCGAGCCAACAC-3Ј 5Ј-GAACCACGAAAGACGGGAAA-3Ј 5Ј-TTCCAACCTGCTGCTCAACA-3Ј 5Ј-TGGAGCTTTGGAGTGGTTCTG-3Ј 5Ј-CACGCGCAGACCTTCGTT-3Ј

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