Inhibition of aquaporin-3 in macrophages by a monoclonal antibody as potential therapy for liver injury.

Hara-Chikuma, Mariko; Tanaka, Manami; Verkman, Alan S; Yasui, Masato · Nat Commun · 2020

basic_science · Level V

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Abstract

Aquaporin 3 (AQP3) is a transporter of water, glycerol and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) that is expressed in various epithelial cells and in macrophages. Here, we developed an anti-AQP3 monoclonal antibody (mAb) that inhibited AQP3-facilitated H<sub>2</sub>O<sub>2</sub> and glycerol transport, and prevented liver injury in experimental animal models. Using AQP3 knockout mice in a model of liver injury and fibrosis produced by CCl<sub>4</sub>, we obtained evidence for involvement of AQP3 expression in nuclear factor-κB (NF-κB) cell signaling, hepatic oxidative stress and inflammation in macrophages during liver injury. The activated macrophages caused stellate cell activation, leading to liver injury, by a mechanism involving AQP3-mediated H<sub>2</sub>O<sub>2</sub> transport. Administration of an anti-AQP3 mAb, which targeted an extracellular epitope on AQP3, prevented liver injury by inhibition of AQP3-mediated H<sub>2</sub>O<sub>2</sub> transport and macrophage activation. These findings implicate the involvement of macrophage AQP3 in liver injury, and provide evidence for mAb inhibition of AQP3-mediated H<sub>2</sub>O<sub>2</sub> transport as therapy for macrophage-dependent liver injury.

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