Calcium-phosphate-mediated Transfection of Cells with High-molecular-weight Genomic DNA

Endothelial cell‑derived CCL15 mediates the transmigration of fibrocytes through the CCL15‑CCR1 axis in vitro

Wound healing is a complex physiological process in which fibrocytes serve a vital role. However, the mechanism underlying the recruitment of fibrocytes during wound healing remains largely unknown. The present study aimed to investigate whether endothelial cells are involved in the recruitment of fibrocytes in wound healing. To mimic the in vivo angiogenic process, a co‑culture system consisting of endothelial cells and fibrocytes was achieved using a permeable Transwell co‑culture system. The expression of chemokines produced by endothelial cells with or without co‑culture was then measured using a gene chip. Based on the dataset from chip analysis, chemokine ligand 15 (CCL15) produced by endothelial cells was identified, which likely serves a regulatory role in mediating the transmigration of fibrocytes. Overexpression of CCL15 in endothelial cells or chemokine receptor 1 (CCR1) in fibrocytes promoted the transmigration of fibrocytes, whilst silencing the expression of CCL15 in endothelial cells or that of CCR1 in fibrocytes attenuated the transmigration of fibrocytes. Results from the present study suggested that the CCL15‑CCR1 axis between endothelial cells and fibrocytes serves a vital role in mediating the recruitment of fibrocytes during wound healing.

Transfection of mammalian cells with fluorescent protein fusions

Fluorescent protein fusions (FPFs) have been used to address a wide range of questions in individual cells as well as in specific tissues of particular organisms. However, investigators must take extreme care when using FPFs to ensure that the resultant fusion protein is expressed at or close to the endogenous level of the parent protein, and also that it is full length, localizes correctly, and behaves normally once incorporated in the cell. Although transient transfection methods can be used to introduce DNA coding for FPFs, in many cases it is beneficial and/or essential to develop stable cell lines expressing the fusion protein of interest. In addition to providing more native levels of expression, the individual clones can be generated from single cells, the integration site of the plasmid can be mapped, and the copy number can be determined. Moreover, because every cell in the population is expressing the fusion protein, cell cycle analyses and biochemical fractionation are significantly easier to accomplish. This article presents a protocol for generating, selecting, and screening stable cell lines expressing FPFs.