Macrophage migration inhibitory factor mediates protease-activated receptor 4-induced bladder pain through urothelial high mobility group box 1.

Fei Ma,David E Hunt,Dimitrios E Kouzoukas,Richard Bucala,Katherine L Meyer-Siegler,Pedro L Vera,Lin Leng

doi:10.14814/phy2.13549

Fei Ma, David E Hunt + Show 5 more

Open Access

PDF Available

https://doi.org/10.14814/phy2.13549

Copy DOI

Export

Save

Cite

Abstract
Highlights/Summary
Full-Text PDF
Similar Papers

Abstract

Listen

Macrophage migration inhibitory factor (MIF) mediates pain although the mechanisms are not well understood. Urothelial activation of protease activated receptor 4 (PAR4) results in urothelial MIF release, urothelial high mobility group box 1 (HMGB1) release and bladder pain in mice without bladder inflammation. All three effects are prevented by MIF inhibition while intravesical disulfide HMGB1 alone can induce bladder pain. This study utilizes genetic MIF deletion to determine whether MIF mediates PAR4‐induced bladder pain and is upstream of HMGB1‐induced bladder pain. Wild type (C57/BL6) and MIF knockout (KO) mice were treated with intravesical PAR4 activating peptide or disulfide HMGB1 and tested for abdominal mechanical hypersensitivity at baseline (before treatment) and 24 h after injection. Micturition parameters and bladder histology were examined after behavioral test. Real‐time PCR and western blotting measured HMGB1 mRNA and protein levels in the bladders of naïve wild type and MIF KO mice, while immunofluorescence measured HMGB1 protein levels in the urothelium of both strains. Intravesical PAR4 activation resulted in abdominal mechanical hypersensitivity in wild‐type mice but not MIF KO mice. Intravesical disulfide HMGB1 induced abdominal mechanical hypersensitivity in both strains. Neither treatment resulted in significant changes in micturition or bladder histology in either strain. HMGB1 mRNA and protein levels were higher in MIF KO mouse bladders and the urothelium of MIF KO bladder had greater immunostaining than the wild‐type strain. MIF is a pivotal molecule mediating PAR4‐induced bladder pain and regulating urothelial HMGB1 production and release to elicit bladder pain.

Highlights

Macrophage migration inhibitory factor (MIF) is a cytokine that is pre-formed in various types of cells and stored in vesicles to be released upon appropriate stimuli (Lolis and Bucala 2003)
We recently reported that activation of urothelial protease activated receptor 4 (PAR4) receptors results in urothelial MIF release, urothelial high mobility group box 1 (HMGB1) release and abdominal mechanical hypersensitivity in mice without resulting in other inflammatory changes or altering voiding behavior
The present results clearly demonstrate that MIF is a signaling molecule mediating bladder pain

Summary

Introduction

Macrophage migration inhibitory factor (MIF) is a cytokine that is pre-formed in various types of cells and stored in vesicles to be released upon appropriate stimuli (Lolis and Bucala 2003). Recent evidence indicates that MIF is involved in nociception, either by mediating pain induced by inflammation or nerve injury (Morand et al 2002; Aloisi et al 2005; Ellis et al 2014) or by eliciting pain directly (Alexander et al 2012; Lerch et al 2014). MIF Mediates HMGB1 in PAR4-Induced Bladder Pain. MIF is expressed in central nervous system cells (including neurons and glial cells) and expressed in peripheral tissues such as macrophages, choroid plexus, anterior pituitary, gastric, colonic, and urinary epithelium (Meyer-Siegler 2001; Lue et al 2002; Vera and MeyerSiegler 2003). MIF release was observed from bladder urothelium and peripheral as well as central nervous system in a different inflammatory model of cystitis in rodents (Vera and Meyer-Siegler 2003; Meyer-Siegler and Vera 2004; Vera et al 2010)

Methods

Results

Conclusion