Abstract
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.
Document Type
Article
Publication Date
12-21-2017
Digital Object Identifier (DOI)
https://doi.org/10.14814/phy2.13549
Funding Information
This study is funded by NIH (DK0093496; PLV).
Related Content
Research data pertaining to this article is located at figshare.com:https://dx.doi.org/10.6084/m9.figshare.5644273
Additional Supporting Information may be found online in the supporting information tab for this article.
Repository Citation
Ma, Fei; Kouzoukas, Dimitrios E.; Meyer-Siegler, Katherine L.; Hunt, David E.; Leng, Lin; Bucala, Richard; and Vera, Pedro L., "Macrophage Migration Inhibitory Factor Mediates Protease-Activated Receptor 4-Induced Bladder Pain Through Urothelial High Mobility Group Box 1" (2017). Physiology Faculty Publications. 105.
https://uknowledge.uky.edu/physiology_facpub/105
Supporting Information: Figure S1.
phy213549-sup-0002-FigureS2.tif (3534 kB)
Supporting Information: Figure S2.
phy213549-sup-0003-data.docx (11 kB)
Supporting Information
Notes/Citation Information
Published in Physiological Reports, v. 5, issue 24, e13549, p. 1-8.
© 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.