A4 PREDNISOLONE, A GLUCOCORTICOID WIDELY USED FOR TREATMENT OF IBD, ENHANCES A HUMAN INTERLEUKIN-4-ACTIVATED MACROPHAGE PHENOTYPE

Background

With cellular immunotherapy, the individuals’ medication could ablate (or enhance) any therapeutic benefit of the transferred cells. Murine and human macrophages activated with IL-4 (i.e., M(IL4)) improve wound healing and reduce the severity of disease in murine models of colitis. Advancing the position that autologous M(IL4) could be a novel approach to IBD, a critical question arises: will concurrent medication impact the M(IL4)s anti-colitic effect? To address this, we tested if prednisolone, a synthetic, anti-inflammatory glucocorticoid used to induce remission in IBD flares,impacts human M(IL4) phenotype and function.

Purpose

To determine if prednisolone suppresses or enhances a human M(IL4) phenotype as defined by canonical marker molecules and wound healing and anti-colitic activities.

Method

Macrophages were differentiated from the blood monocytes of healthy volunteers using M-CSF (7 days) and treated with GMP-grade IL-4 (10 ng/mL, 48h) ± a 24h treatment with prednisolone (1μg/mL). Subsequently, conditioned medium was collected for TGFb measurement by ELISA and for use in a T84 epithelial cell in vitro wound healing assay. Retrieved M(IL4) and M(IL4,pred.) were characterized by mRNA expression of CD206 (mannose receptor), RAMP1 (CGRP receptor), and CD14 (LPS co-receptor). One million murine bone marrow-derived M(IL4) or M(IL4,pred.) were injected into BALB/c mice 48h prior to intra-rectal DNBS (3mg), and colitis was assessed 72h-post DNBS.

Result(s)

Human M(IL4)s displayed increased mRNA expression of CD206 and RAMP1, and reduced CD14 compared to M(0), with the CD206 and RAMP1 being further increased by prednisolone treatment. M(IL4,pred.) produced more TGF-β than M(IL4) upon LPS stimulation [363 ± 30 vs. 241 ± 24 pg/ml, n= 4, p<0.05], which would predict an enhanced wound healing capacity. Stimulated M(IL4,pred.) produced more IL-10 than M(IL4). Furthermore, murine M(IL4,pred.) retained an anti-colitic capacity comparable to M(IL4) as determined by disease activity score in the DNBS model.

Conclusion(s)

Human M(IL4)s subsequently exposed to the potent immunomodulatory glucocorticoid, prednisolone show increased expression of phenotypic markers and increased output of TGFb and IL-10. Crucially M(IL4,pred.) retained an anti-colic effect in the murine DNBS model of colitis. Interpreting these data, we suggest that the anti-colitic effect of M(IL4) immunotherapy would not be adversely offset by the individuals concomitant use of steroids. Our preliminary findings support pursuing M(IL4) transfers as a novel approach to the management of IBD.

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Helmsley Charitable Trust

Disclosure of Interest

None Declared

A60 THE NEURAL SIGNAL, CALCITONIN GENE-RELATED PEPTIDE (CGRG) ENHANCES A REGULATORY PHENOTYPE IN THE HUMAN IL-4 TREATED HUMAN MACROPHAGE

Background

Recent studies in pre-clinical models of disease have revealed the ability of murine and human IL-4-treated macrophages (M(IL4)) to promote wound recovery and reduce the severity of colitis. An unbiased RNA-sequence analysis of human blood-derived macrophages revealed increased expression of the RAMP1 chain of the CGRP receptor in IL-4 treated cells, raising the intriguing possibility of neural control of regulatory macrophages in the context of neuroimmune interaction in colitis. Thus, we sought to address if this mRNA signal translated into increased RAMP1 protein, if/how CGPR affected M(IL4) function, and if this applied to macrophages from patients with IBD as well as those from healthy donors.

Aims

To determine if CRGP-RAMP1 signalling in human IL-4 treated macrophages enhances a regulatory phenotype.

Methods

Peripheral blood mononuclear cells from healthy volunteers and individuals with IBD were cultured on plastic (2h, 37°C) and non-adherent cells removed. The adherent cells were cultured with recombinant hM-CSF (10 ng/ml) for 7 days. The resultant macrophages (2.5×105) were differentiated with IL-4 (48h 20 ng/mL) and assessed by qPCR and immunocytochemistry. In other cells, CGRP (10 nM) was added 24h after IL-4 and (1) cAMP (2) cytokines and (3) phagocytosis of inert FITC-beads measured, and (4) the capacity of supernatant from the cells to promote healing in wounded Caco2 epithelial monolayers tested.

Results

Compared to non-treated macrophages (M(0)), M(IL4)s from healthy individuals had increased mRNA for both chains of the CGRP-receptor (i.e. RAMP1 and CLR), and increased surface expression of the receptor as shown by immunostaining and CGRP-evoked cAMP. The IL-4 evoked RAMP1 mRNA was only detected in macrophages from 50% of the patients with active IBD. M(IL4)s treated with CGRP showed enhanced expression of the mannose receptor (CD206, allows detection of bacteria), increase phagocytosis of inert beads/macrophages. Moreover, CGRP increases VEGF and CCL18 expression in M(IL4), and soluble mediators from these cells promoted in vitro epithelial wound repair.

Conclusions

Reduced expression of CGRP and its receptor has been shown in IBD. The findings herein, demonstrating how CGRP-RAMP1 signalling can reinforce and enhance a regulatory, reparatory phenotype in human macrophages reveals another aspect of IBD pathophysiology. We speculate that loss of this neuroimmune axis (i.e. CGRP/Nerve-M(IL4) interaction) has the potential to significantly impair mucosal healing in IBD.

Funding Agencies

CCCAlberta Innovates in Health Innovation

A74 HELMINTH ANTIGENS OR REGULATORY MACROPHAGES REDUCE THE SEVERITY OF COLORECTAL CANCER

Background

Infection with helminth parasites is a potent stimulus of immunity, and murine model systems reveal that a bystander benefit of this response to helminths is suppression of colitis. Unraveling the mechanism of this inhibition of colitis, the regulatory macrophage has emerged as a cell of interest in ‘helminth therapy’. Given the relationship between inflammation and cancer – patients with inflammatory bowel disease (IBD) have a higher risk of colorectal cancer (CRC).

Aims

To test the hypothesis that intraperitoneal administration of excretory/secretory products from the tapeworm Taenia crassiceps (TcES) or IL-4-treated macrophages (M(IL-4)) (characteristic of the immune response to helminths) would affect the outcome of CRC.

Methods

CRC was induced in female BALB/c and male C57Bl/6 mice using azoxymethane (AOM) (10 mg, ip) and three cycles of Dextran sulfate sodium (DSS: 7 days, 1–2% wt./vol.) separated by 2 weeks of normal tap water. Following initiation of CRC, mice received TcES (200 μg, ip.) - or M(IL-4) (106, ip). On necropsy, CRC incidence, number, and size of the tumour were recorded and tumors assessed histologically.

Results

Mice receiving TcES or M(IL-4)s were substantially protected from AOM-DSS induced CRC, as shown by statistically significant reductions in tumor number and size, although the number of mice developing tumors was unchanged (n=4–8 mice). The suppression of CRC in TcES-treated mice correlated with reduced mobilization of STAT3 and NF-κB signaling cascades in the as determined by immunostaining and immunoblot of whole tissue extracts.

Conclusions

With the speculation that helminth-derived molecules or transfer of in vitro educated macrophages could be used to treat IBD comes the specter of the putative oncogenic effects of regulatory macrophages. Contrary to this, the data herein show that the TcES reduced CRC; and, that murine macrophages (M(IL4)) also actually limit the severity of inflammation-driven CRC by directly targeting the cancer cells or reducing the inflammatory stimulus. These findings add emphasis to the consideration of autologous regulatory macrophage transfer to treat IBD and CRC

Funding Agencies

CCCCONACYT (Mexico)

A264 HELMINTH-INFECTION MOBILIZES HOST AND MICROBIAL FACTORS THAT CO-OPERATE TO SUPPRESS CHEMICAL-INDUCED COLITIS IN MICE

Background

Infection with helminth parasites suppresses inflammation in murine model systems; for example, IL-10 is important in Hymenolepis diminuta-inhibition of DNBS-induced colitis. Bacteria-derived products can have anti-inflammatory effects. Given that infection with H. diminuta, or other parasitic worms, results in perturbation of the gut microbiota, the present study tested a role for bacteria in helminth-suppression of colitis by assessing reciprocity between IL-10 and butyrate signaling in the amelioration of colitis.

Aims

To determine if a functional relationship exists between IL-10 and butyrate in the inhibition of colitis observed following infection with the lumen-dwelling tapeworm, Hymenolepis diminuta.

Methods

Colitis was induced in male BALB/c mice by intra-rectal dinitrobenzene sulphonic acid (DNBS) (3 mg/~22g mouse), with necropsy and assessment 3 days later. Mice received either infection with five H. diminuta cysticercoids by gavage or daily butyrate enemas or acetate in their drinking water. Immunostaining assessed IL-10R protein expression on formalin-fixed sections of colon. The murine IEC4.1 epithelial cell line and epithelial organoids were treated with butyrate and mRNA for the IL10Rα chain assessed, as was colonic tissue from mice.

Results

Mice infected with H. diminuta or receiving butyrate enemas (n=8–12) were protected from DNBS-induced colitis as gauged by colon length, and macroscopic disease and histopathology scores. Addition of acetate to the drinking water resulted in a more modest anti-colitic effect. Suppression of colitis was accompanied by increased epithelial expression of IL-10 in butyrate- and H. diminuta-treated mice, with the later also showing upregulation of the IL-10R on lamina propria cells; an effect negated by co-treating the mice with broad spectrum antibiotics. In vitro analyses revealed increased IL10Rα mRNA in butyrate-treated epithelia (n=4).

Conclusions

This study begins to tease apart the host (i.e. IL-10) and bacterial (i.e. butyrate) molecules that mediate H. diminuta-evoked suppression of colitis in a murine model. These proof-of-principle data suggest that knowledge of the individual patient (i.e. immunological basis of their disease and their microbiota) may be a critical determinant of the success or failure of helminth therapy.

Funding Agencies

CAG, CCCNSERC