Cyclophosphamide-induced cystitis increases bladder CXCR4 expression and CXCR4-macrophage migration inhibitory factor association.

Abstract

BACKGROUND:

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine involved in cystitis and a non-cognate ligand of the chemokine receptor CXCR4 in vitro. We studied whether CXCR4-MIF associations occur in rat bladder and the effect of experimental cystitis.

METHODS AND FINDINGS:

Twenty male rats received saline or cyclophosphamide (40 mg/kg; i.p.; every 3(rd) day) to induce persistent cystitis. After eight days, urine was collected and bladders excised under anesthesia. Bladder CXCR4 and CXCR4-MIF co-localization were examined with immunhistochemistry. ELISA determined MIF and stromal derived factor-1 (SDF-1; cognate ligand for CXCR4) levels. Bladder CXCR4 expression (real-time RTC-PCR) and protein levels (Western blotting) were examined. Co-immunoprecipitations studied MIF-CXCR4 associations.Urothelial basal and intermediate (but not superficial) cells in saline-treated rats contained CXCR4, co-localized with MIF. Cyclophosphamide treatment caused: 1) significant redistribution of CXCR4 immunostaining to all urothelial layers (especially apical surface of superficial cells) and increased bladder CXCR4 expression; 2) increased urine MIF with decreased bladder MIF; 3) increased bladder SDF-1; 4) increased CXCR4-MIF associations.

CONCLUSIONS:

These data demonstrate CXCR4-MIF associations occur in vivo in rat bladder and increase in experimental cystitis. Thus, CXCR4 represents an alternative pathway for MIF-mediated signal transduction during bladder inflammation. In the bladder, MIF may compete with SDF-1 (cognate ligand) to activate signal transduction mediated by CXCR4.

• Authors: Pedro L Vera, Kenneth A Iczkowski, Xihai Wang, Katherine L Meyer-Siegler
• Journal: PloS one (PLoS One) Vol. 3 Issue 12 Pg. e3898 ( 2008) ISSN: 1932-6203 [Electronic] United States
• PMID: 19066630 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Chemokine CXCL12
• Macrophage Migration-Inhibitory Factors
• Receptors, CXCR4
• Sodium Chloride
• Cyclophosphamide

Topics

• Animals
• Body Weight (drug effects)
• Chemokine CXCL12 (metabolism)
• Cyclophosphamide (pharmacology)
• Cystitis (chemically induced, genetics)
• Macrophage Migration-Inhibitory Factors (metabolism, urine)
• Male
• Protein Binding (drug effects)
• Rats
• Rats, Sprague-Dawley
• Receptors, CXCR4 (genetics, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction
• Sodium Chloride (pharmacology)
• Up-Regulation (drug effects)
• Urinary Bladder (metabolism, pathology)
• Urothelium (drug effects, metabolism, pathology)