In vivo and ex vivo assessment of bladder hyper-permeability and using molecular targeted magnetic resonance imaging to detect claudin-2 in a mouse model for interstitial cystitis

• Published in: PloS one Vol. 15; no. 10; p. e0239282
• Main Authors: Smith, Nataliya, Saunders, Debra, Lerner, Megan, Zalles, Michelle, Mamedova, Nadezda, Cheong, Daniel, Mohammadi, Ehsan, Yuan, Tian, Luo, Yi, Hurst, Robert E., Greenwood-Van Meerveld, Beverley, Towner, Rheal A.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 23.10.2020; Public Library of Science (PLoS)
• Subjects: Albumins; Animals; Antibodies; Antibodies - chemistry; Antibodies - immunology; Biology and Life Sciences; Biotin; Bladder; Catheters; Cell permeability; Cellular proteins; Claudin-2 - immunology; Claudin-2 - metabolism; Cystitis; Cystitis, Interstitial - metabolism; Cystitis, Interstitial - pathology; Diethylene triamine; Disease Models, Animal; Electrical resistivity; Gadolinium; Gadolinium DTPA - chemistry; Gene expression; Health aspects; Health sciences; Immunofluorescence; Immunohistochemistry; In vivo methods and tests; Interstitial cystitis; Lipopolysaccharides; Lipopolysaccharides - toxicity; Magnetic permeability; Magnetic resonance; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Medical imaging; Medical research; Medicine and Health Sciences; Membrane permeability; Membrane proteins; Mice; Molecular Probes - chemistry; Monocyte chemoattractant protein 1; Neurosciences; Pain; Permeability; Permeability - drug effects; Peroxidase; Physical Sciences; Physiological aspects; Physiology; Proteins; Research and Analysis Methods; Serum Albumin - chemistry; Streptavidin; Urinary Bladder - physiopathology; Urology; Urothelium; Zonula occludens-1 protein; United States; United States > US; Oklahoma
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0239282

To determine if the URO-MCP-1 mouse model for bladder IC/BPS is associated with in vivo bladder hyper-permeability, as measured by contrast-enhanced MRI (CE-MRI), and assess whether molecular-targeted MRI (mt-MRI) can visualize in vivo claudin-2 expression as a result of bladder hyper-permeability. Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic, painful condition of the bladder that affects primarily women. It is known that permeability plays a substantial role in IC/BPS. Claudins are tight junction membrane proteins that are expressed in epithelia and endothelia and form paracellular barriers and pores that determine tight junction permeability. Claudin-2 is a molecular marker that is associated with increased hyperpermeability in the urothelium. CE-MRI was used to measure bladder hyper-permeability in the URO-MCP-1 mice. A claudin-2-specific mt-MRI probe was used to assess in vivo levels of claudin-2. The mt-MRI probe consists of an antibody against claudin-2 conjugated to albumin that had Gd-DTPA (gadolinium diethylenetriamine pentaacetate) and biotin attached. Verification of the presence of the mt-MRI probe was done by targeting the biotin moiety for the probe with streptavidin-horse radish peroxidase (SA-HRP). Trans-epithelial electrical resistance (TEER) was also used to assess bladder permeability. The URO-MCP-1 mouse model for IC/BPS was found to have a significant increase in bladder permeability, following liposaccharide (LPS) exposure, compared to saline-treated controls. mt-MRI- and histologically-detectable levels of the claudin-2 probe were found to increase with LPS -induced bladder urothelial hyper-permeability in the URO-MCP-1 IC mouse model. Levels of protein expression for claudin-2 were confirmed with immunohistochemistry and immunofluorescence imaging. Claudin-2 was also found to highly co-localize with zonula occlidens-1 (ZO-1), a tight junction protein. The combination of CE-MRI and TEER approaches were able to demonstrate hyper-permeability, a known feature associated with some IC/BPS patients, in the LPS-exposed URO-MCP-1 mouse model. This MRI approach could be clinically translated to establish which IC/BPS patients have bladder hyper-permeability and help determine therapeutic options. In addition, the in vivo molecular-targeted imaging approach can provide invaluable information to enhance our understanding associated with bladder urothelium hyper-permeability in IC/BPS patients, and perhaps be used to assist in developing further therapeutic strategies.