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The behavior of fibroblasts from the developing avian cornea. Morphology and movement in situ and in vitro
Insights
Chick cornea fibroblasts exhibit contact inhibition of movement (CIM) in vivo and in vitro, influencing cell migration despite differences in cell morphology and behavior during development.
Area of Science:
- Developmental biology
- Cell biology
- Ophthalmology
Background:
- The developing chick cornea contains an acellular collagenous stroma invaded by neural crest-derived fibroblasts.
- Corneal stroma thickness increases significantly during development (stage 27-28).
Purpose of the Study:
- To compare the migratory behavior of chick corneal fibroblasts in situ within developing corneas versus in vitro in artificial collagen lattices and on glass.
- To investigate the role of contact inhibition of movement (CIM) in fibroblast migration during corneal development.
Main Methods:
- Nomarski light microscopy was used to observe and film fibroblast movement.
- Comparative analysis of cell behavior in isolated corneas, collagen lattices, and on glass substrates.
Main Results:
- In situ, fibroblasts display pseudopodia and filopodia, with movement involving cytoplasmic processes, unlike the ruffled lamellipodia seen on glass.
- Fibroblasts in situ and in collagen lattices exhibit classical contact inhibition of movement (CIM) during pairwise collisions.
- Dividing cells in situ extend filopodia during telophase but do not show surface blebbing.
Conclusions:
- Contact inhibition of movement (CIM) is a fundamental mechanism controlling fibroblast migration in both in vivo and in vitro environments.
- Despite morphological differences, the underlying principles of cell movement and interaction, including CIM, are conserved across different substrates.
Abstract:
The early chick cornea is composed of an acellular collagenous stroma lined with an anterior epithelium and a posterior endothelium. At stage 27-28 of development (5 1/2 days), this stroma swells so that the cornea is 75-120 mum thick. At the same time, fibroblasts that originate from the neural crest begin to invade this stroma. Using Nomarski light microscopy, we have compared the behavior of moving cells in isolated corneas with the migratory activities of the same cells in artificial collagen lattices and on glass. In situ, fibroblasts have cyclindrical bodies from which extend several thick pseudopodia and/or finer filopodia. Movement is accompanied by activity in these cytoplasmic processes. The flat ruffling lamelli-podia that characterize these cells on glass are not seen in situ, but the general mechanism of cell movement seems to be the same as that observed in vitro: either gross contraction or recoil of the cell body (now pear shaped) into the forward cell process, or more subtle "flowing" of cytoplasm into the forward cell process without immediate loss of the trailing cell process. We filmed collisions between cells in situ and in three-dimensional collagen lattices. These fibroblasts show, in their pair-wise collisions, the classical contact inhibition of movement (CIM) exhibited in vitro even though they lack ruffled borders. On glass these cells multi-layer, showing that, while CIM affects cell movement, fibroblasts can use one another as a substratum. Postmitotic cells show CIM in moving away from each other. Interestingly, dividing cells in situ do not exhibit surface blebbing, but do extend filopodia at telophase. The role of CIM in controlling cell movement in vivo and in vitro is stressed in the discussion.