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High-resolution Time-lapse Imaging and Automated Analysis of Microtubule Dynamics in Living Human Umbilical Vein Endothelial Cells

The physiological process by which new vasculature forms from existing vasculature requires specific signaling events that trigger morphological changes ...

University of the Sciences in Philadelphia

Endothelial cells (ECs) migrate directionally during angiogenesis and wound healing by polarizing to extracellular cues to guide directional movement. EC polarization is controlled by microtubule (MT) growth dynamics, which are regulated by MT-associated proteins (MAPs) that alter MT stability. Mitotic centromere-associated kinesin (MCAK) is a MAP that promotes MT disassembly within the mitotic spindle, yet its function in regulating MT dynamics to promote EC polarity and migration has not been investigated. We used high-resolution fluorescence microscopy coupled with computational image analysis to elucidate the role of MCAK in regulating MT growth dynamics, morphology, and directional migration of ECs. Our results show that MCAK-mediated depolymerization of MTs is specifically targeted to the trailing edge of polarized wound-edge ECs. Regulation of MCAK function is dependent on Aurora A kinase, which is regionally enhanced by signaling from the small guanosine triphosphatase, Rac1. Thus, a Rac1-Aurora A-MCAK signaling pathway mediates EC polarization and directional migration by promoting regional differences in MT dynamics in the leading and trailing cell edges.

Rac1 and Aurora A regulate MCAK to polarize microtubule growth in migrating endothelial cells.

Prolonged hypoxia, the event of insufficient oxygen, is known to upregulate tumor development and growth by promoting the formation of a neoplastic environment. The recent discovery that a subset of cellular microRNAs (miRs) are upregulated during hypoxia, where they function to promote tumor development, highlights the importance of hypoxia-induced miRs as targets for continued investigation. miRs are short, non-coding transcripts involved in gene expression and regulation. Under hypoxic conditions, miR-210 becomes highly upregulated in response to hypoxia inducing factors (HIFs). HIF-1α drives miR-210's overexpression and the resultant alteration of cellular processes, including cell cycle regulation, mitochondria function, apoptosis, angiogenesis and metastasis. Here we discuss hypoxia-induced dysregulation of miR-210 and the resultant changes in miR-210 protein targets that regulate cancer progression. Potential methods of targeting miR-210 as a therapeutic tool are also explored.

Kyvan Dang

Department of Biological Sciences

University of the Sciences in Philadelphia

High-resolution Time-lapse Imaging and Automated Analysis of Microtubule Dynamics in Living Human Umbilical Vein Endothelial Cells

Kyvan Dang

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Biological Sciences

University of the Sciences in Philadelphia

High-resolution Time-lapse Imaging and Automated Analysis of Microtubule Dynamics in Living Human Umbilical Vein Endothelial Cells

Department of Biological Sciences