Poster, Podium & Video Sessions
Presentation Authors: Evaristus Mbanefo, Loc Le, Rockville, MD, Luke Pennington, Theodore Jardetzky, Stanford, CA, Abdulaziz Alouffi, Franco Falcone, Nottingham, United Kingdom, Michael Hsieh*, Washington, DC
Introduction: Ifosfamide-induced hemorrhagic cystitis and bladder hypersensitivity can be difficult to manage when mesna fails to prevent them. Bladder hypersensitivity associated with various forms of cystitis may be refractory to multiple treatment modalities. Prior work suggests interleukin-4 (IL4) alleviates ifosfamide-induced hemorrhagic cystitis and resiniferatoxin (capsaicin receptor agonist)-induced bladder pain. IL4-inducing principle of Schistosoma mansoni eggs (IPSE) is a host modulatory protein that binds immunoglobulins on leukocytes thereby inducing IL4 production and translocates into host nuclei to alter gene transcription. We sought to determine if the S. haematobium homolog of IPSE (H-IPSE) would reduce ifosfamide- and resiniferatoxin-induced bladder pathology.
Methods: We cloned and expressed H-IPSE and a nuclear localization sequence (NLS)-deficient mutant H-IPSE (H-IPSE[NLS]). H-IPSE IgE binding was measured by ELISA. H-IPSE activation of IgE-bearing basophils was assayed using RSATL8 basophilic reporter cells. Cellular uptake and NLS-dependent nuclear translocation of H-IPSE and H-IPSE(NLS) were confirmed using HTB9 urothelial cells and fluorescence microscopy. We administered IL4, H-IPSE, H-IPSE+anti-IL4 antibody, H-IPSE(NLS), or H-IPSE(NLS)+anti-IL4 antibody to mice prior to ifosfamide (with and without mesna) or resiniferatoxin. Negative controls were administered saline only. Positive controls were administered ifosfamide only. Previously published metrics for pain and urinary frequency were interpreted in blinded fashion. Bladder histology was interpreted in blinded fashion. Bladder hemoglobin was quantified using Drabkin&[prime]s assay. Bladder gene expression was assessed via real-time PCR.
Results: H-IPSE bound IgE in vitro and activated IgE-bearing RSATL8 cells. Nuclear translocation of H-IPSE but not H-IPSE(NLS) was confirmed. H-IPSE was superior to mesna and IL4 in suppressing ifosfamide-induced bladder hemorrhage (IL4-dependent). H-IPSE was comparable to mesna in dampening ifosfamide-triggered pain behaviors (NLS-dependent) and urinary frequency (NLS-dependent). H-IPSE reduced resiniferatoxin-mediated freezing behaviors (IL4- and NLS-dependent). H-IPSE reduced mRNA expression of proinflammatory mediators and increased expression of uroplakin mRNA.
Conclusions: Our work suggests a uropathogen-derived host modulatory protein has therapeutic effects in bladder disease models.
Source Of Funding: None