NRF2 promotes urothelial cell response to bacterial infection by regulating reactive oxygen species and RAB27B expression.

Chetanchandra S Joshi,Amy Mora,Indira U Mysorekar,Paul A Felder

doi:10.1016/j.celrep.2021.109856

Chetanchandra S Joshi, Amy Mora + Show 2 more

Open Access

https://doi.org/10.1016/j.celrep.2021.109856

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Journal: Cell Reports	Publication Date: Oct 1, 2021
Citations: 25	License type: cc-by

Affiliation: University of Washington

Abstract

Uropathogenic Escherichia coli (UPEC) cause urinary tract infections (UTIs) by invading urothelial cells. In response, the host mounts an inflammatory response to expel bacteria. Here, we show that the NF-E2-related factor 2 (NRF2) pathway is activated in response to UPEC-triggered reactive oxygen species (ROS) production. We demonstrate the molecular sequence of events wherein NRF2 activation in urothelial cells reduces ROS production, inflammation, and cell death, promotes UPEC expulsion, and reduces the bacterial load. In contrast, loss of NRF2 leads to increased ROS production, bacterial burden, and inflammation, both invitro and invivo. NRF2 promotes UPEC expulsion by regulating transcription of the RAB-GTPase RAB27B. Finally, dimethyl fumarate, a US Food and Administration-approved NRF2 inducer, reduces the inflammatory response, increases RAB27B expression, and lowers bacterial burden in urothelial cells and in a mouse UTI model. Our findings elucidate mechanisms underlying the host response to UPEC and provide a potential strategy to combat UTIs.

Highlights

Urinary tract infections (UTIs) are the most common infections, accounting for approximately eight million clinic and emergency department visits per year in the United States (Dielubanza and Schaeffer, 2011)
We focus on NF-E2-related factor 2 (NRF2) because oxidative stress causes NRF2 to dissociate from its negative regulator Kelch-like ECH associated protein 1 (KEAP1) in the cytoplasm and translocate to the nucleus, where NRF2 binds to antioxidant response elements (AREs) to promote transcription of antioxidant genes such as NAD(P)H quinone dehydrogenase 1 (NQO1), glutamate-cysteine ligase catalytic subunit (GCLC), and heme oxygenase 1 (HMOX1) (Itoh et al, 1999)
uropathogenic Escherichia coli (UPEC) infection triggers reactive oxygen species (ROS) production and activates the NRF2 pathway in urothelial cells To test the hypothesis that UPEC infection promotes the production of ROS in urothelial cells, we infected human 5,637 bladder carcinoma epithelial cells with UPEC (UTI89, a clinical isolate) (Hung et al, 2009) for up to 8 h, washed them thoroughly, and stained them with the ROS indicator dye 20,70-dichlorodihydrofluorescein diacetate (H2DCF)

Summary

Introduction

More than 85% of UTIs are caused by uropathogenic Escherichia coli (UPEC) (Dielubanza and Schaeffer, 2011) that are able to use type-1 fimbria to attach to uroplakin proteins on the luminal surface of superficial cells of the urothelium (Zhou et al, 2001). Toll-like receptor 4 (TLR4) on urothelial cells recognizes UPEC and activates a signaling cascade, leading to the secretion of pro-inflammatory cytokines such as interleukin (IL)-6 and IL-1b (Bishop et al, 2007; Schilling et al, 2001). After they are invaded with bacteria, the urothelial cells exocytose the bacteria in a process that relies on the Rab

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