Basic Research
Copyright ©2007 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Feb 21, 2007; 13(7): 1032-1041
Published online Feb 21, 2007. doi: 10.3748/wjg.v13.i7.1032
Role of soluble factors and three-dimensional culture in in vitro differentiation of intestinal macrophages
Tanja Spoettl, Martin Hausmann, Katrin Menzel, Heidi Piberger, Hans Herfarth, Juergen Schoelmerich, Frauke Bataille, Gerhard Rogler
Tanja Spoettl, Martin Hausmann, Katrin Menzel, Heidi Piberger, Hans Herfarth, Juergen Schoelmerich, Frauke Bataille, Gerhard Rogler, Department of Internal Medicine I, and Institute of Pathology, University of Regensburg, Regensburg 93042, Germany
Author contributions: All authors contributed equally to the work.
Supported by the Deutsche Forschungsgemeinschaft (SFB585, Ro 1236/3-2) and the BMBF Kompetenznetz-CED
Correspondence to: Gerhard Rogler, MD, PhD, Department of Internal Medicine I, University Hospital of Zuerich, Raemistrasse 100, 8091 Zuerich, Switzerland. gerhard.rogler@usz.ch
Telephone: +49-941-9447180 Fax: +49-941-9447179
Received: May 16, 2006
Revised: July 3, 2006
Accepted: September 20, 2006
Published online: February 21, 2007
Abstract

AIM: To examine the factor(s) involved in differentiation of intestinal macrophages (IMACs) using a recently established in vitro model.

METHODS: To test whether soluble or membrane bound factors induce IMAC-differentiation, freshly elutriated monocytes (MO) were incubated with conditioned media or cell membranes of intestinal epithelial cells (IEC) or cultured with IEC in transwell systems. To determine the importance of an active migration of MO, three-dimensional aggregates from a 1:1-mixture of MO and IEC were examined by immunohistochemistry and flow cytometry. Apoptosis was examined by caspase-3 Western blots. Extracellular matrix production in differentiation models was compared by immunohistochemistry.

RESULTS: IMAC differentiation was observed in a complex three-dimensional co-culture model (multicellular spheroid, MCS) with IEC after migration of MO into the spheroids. By co-culture of MO with conditioned media or membrane preparations of IEC no IMAC differentiation was induced. Co-culture of MO with IEC in transwell-cultures, with the two cell populations separated by a membrane also did not result in intestinal-like differentiation of MO. In contrast to IEC-spheroids with immigrating MO in mixed MCS of IEC and MO only a small subpopulation of MO was able to survive the seven day culture period.

CONCLUSION: Intestinal-like differentiation of MO in vitro is only induced in the complex three-dimensional MCS model after immigration of MO indicating a role of cell-matrix and/or cell-cell interactions during the differentiation of IMACs.

Keywords: Intestinal macrophages; Intestinal epithelial cells; Multicellular spheroids; Inflammatory bowel disease; Tolerance differentiation