PLoS ONE (Jan 2013)

Targeting p35/Cdk5 signalling via CIP-peptide promotes angiogenesis in hypoxia.

  • Alessandra Bosutti,
  • Jie Qi,
  • Roberta Pennucci,
  • David Bolton,
  • Sabine Matou,
  • Kamela Ali,
  • Li-Huei Tsai,
  • Jerzy Krupinski,
  • Eugene B Petcu,
  • Joan Montaner,
  • Raid Al Baradie,
  • Francesca Caccuri,
  • Arnaldo Caruso,
  • Giulio Alessandri,
  • Shant Kumar,
  • Cristina Rodriguez,
  • Jose Martinez-Gonzalez,
  • Mark Slevin

DOI
https://doi.org/10.1371/journal.pone.0075538
Journal volume & issue
Vol. 8, no. 9
p. e75538

Abstract

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Cyclin-dependent kinase-5 (Cdk5) is over-expressed in both neurons and microvessels in hypoxic regions of stroke tissue and has a significant pathological role following hyper-phosphorylation leading to calpain-induced cell death. Here, we have identified a critical role of Cdk5 in cytoskeleton/focal dynamics, wherein its activator, p35, redistributes along actin microfilaments of spreading cells co-localising with p(Tyr15)Cdk5, talin/integrin beta-1 at the lamellipodia in polarising cells. Cdk5 inhibition (roscovitine) resulted in actin-cytoskeleton disorganisation, prevention of protein co-localization and inhibition of movement. Cells expressing Cdk5 (D144N) kinase mutant, were unable to spread, migrate and form tube-like structures or sprouts, while Cdk5 wild-type over-expression showed enhanced motility and angiogenesis in vitro, which was maintained during hypoxia. Gene microarray studies demonstrated myocyte enhancer factor (MEF2C) as a substrate for Cdk5-mediated angiogenesis in vitro. MEF2C showed nuclear co-immunoprecipitation with Cdk5 and almost complete inhibition of differentiation and sprout formation following siRNA knock-down. In hypoxia, insertion of Cdk5/p25-inhibitory peptide (CIP) vector preserved and enhanced in vitro angiogenesis. These results demonstrate the existence of critical and complementary signalling pathways through Cdk5 and p35, and through which coordination is a required factor for successful angiogenesis in sustained hypoxic condition.