Abstract
Hypoxia is a microenvironmental stress in many pathological conditions, including wound healing and tumor invasion. Under hypoxia, the cells are forced to adapt alternative and self-supporting mechanisms. Understanding these mechanisms may lead to new insights into human disorders. We report here a novel autocrine signaling mechanism by which hypoxia promotes human keratinocyte (HK) migration. First, hypoxia triggers HKs to secrete heat shock protein 90-alpha (HSP90α) via a HIF1-dependent pathway. The secreted HSP90α in turn promotes migration, but not proliferation, of the cells. Disruption of the secretion or extracellular function of HSP90α blocked hypoxia-stimulated HK migration. The ubiquitously expressed surface receptor, LRP1 (LDL-receptor-related protein 1), mediates the HSP90α signaling. Inhibition of LRP1 binding to extracellular HSP90α by neutralizing antibodies or genetic silencing of the LRP1 receptor by RNAi completely nullified hypoxia-driven HK migration. Finally, re-introducing a RNAi-resistant LRP1 cDNA into LRP1-downregulated HKs rescued the motogenic response of the cells to hypoxia. We propose that the hypoxia-HSP90α-LRP1 autocrine loop provides previously unrecognized therapeutic targets for human disorders such as chronic wounds and cancer invasion.
Original language | English (US) |
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Pages (from-to) | 1495-1498 |
Number of pages | 4 |
Journal | Journal of cell science |
Volume | 122 |
Issue number | 10 |
DOIs | |
State | Published - May 15 2009 |
Keywords
- Cell motility
- HSP90α
- Hypoxia
- Keratinocytes
- LRP1
ASJC Scopus subject areas
- Cell Biology