Analysis of fibroblast migration dynamics in idiopathic pulmonary fibrosis using image-based scaffolds of the lung extracellular matrix.

Abstract

Idiopathic pulmonary fibrosis (IPF) is characterized by a profound remodeling of the collagen in the extracellular matrix (ECM), where the fibers become both denser and more highly aligned. However, it is unknown how this reconfiguration of the collagen matrix affects disease progression. Here, we investigate the role of specific alterations in collagen fiber organization on cell migration dynamics by using biomimetic image-based collagen scaffolds representing normal and fibrotic lung, where the designs are derived directly from high-resolution second harmonic generation microscopy images. The scaffolds are fabricated by multiphoton-excited (MPE) polymerization, where the process is akin to three-dimensional printing, except that it is performed at much greater resolution (∼0.5 microns) and with collagen and collagen analogs. These scaffolds were seeded with early passaged primary human normal and IPF fibroblasts to enable the decoupling of the effect of cell-intrinsic characteristics (normal vs. IPF) versus ECM structure (normal vs. IPF) on migration dynamics. We found that the highly aligned IPF collagen structure promoted enhanced cell elongation and F-actin alignment along with increased cell migration speed and straightness relative to the normal tissues. Collectively, the data are consistent with an enhanced contact guidance mechanism on the aligned IPF matrix. Although cell intrinsic effects were observed, the aligned collagen matrix morphology had a larger effect on these metrics. Importantly, these biomimetic models of the lung cannot be synthesized by conventional fabrication methods. We suggest that the MPE image-based fabrication method will enable additional hypothesis-based testing studies of cell-matrix interactions in the context of tissue fibrosis.