Down-regulation of Aquaporin-1 mediates a microglial phenotype switch affecting glioma growth

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Item Type:	Article
Title:	Down-regulation of Aquaporin-1 mediates a microglial phenotype switch affecting glioma growth
Creators Name:	Hu, F., Huang, Y., Semtner, M., Zhao, K., Tan, Z., Dzaye, O., Kettenmann, H., Shu, K. and Lei, T.
Abstract:	Aquaporin 1 (AQP1), a transmembrane protein that forms water channels, has previously been shown to facilitate growth and progression of many types of tumors by modulating tumor cell migration, proliferation and angiogenesis. Here, we determined the impact of AQP1 expression in the tumor environment on the progression of brain tumors. Primary microglia from wild type(WT) and AQP1 knockout(KO) mice were used to test AQP1 effect on microglia function by using Western blot, quantative PCR, in an experimental in vivo mouse glioma model and organotypic brain slice culture. Deletion of AQP1 in the host tissue significantly reduced the survival of the mice implanted with GL261 glioma cells. The density of glioma-associated microglia/macrophages was almost doubled in AQP1KO mice. We found that factors secreted from GL261 cells decrease microglial AQP1 expression via the MEK/ERK pathway, and that inhibition of this pathway with Trametinib reduced tumor growth and prolonged the survival of tumor bearing mice, an effect which required the presence of microglia. Deletion of AQP1 in cultured microglia resulted in an increase in migratory activity and a decrease in TLR4-dependent innate immune responses. Our study demonstrates a functional relevance of AQP1 expression in microglia and hints to AQP1 as a potential novel target for glioma therapy.
Keywords:	Aquaporin-1, Microglia, Glioma, Phenotype-Switch, MEK/ERK, Animals, Mice
Source:	Experimental Cell Research
ISSN:	0014-4827
Publisher:	Elsevier
Volume:	396
Number:	2
Page Range:	112323
Date:	15 November 2020
Official Publication:	https://doi.org/10.1016/j.yexcr.2020.112323
PubMed:	View item in PubMed

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