Brief communication Inhibition of LPS-induced proinflammatory responses of J774.2 macrophages by immobilized enzymatically tailored pectins M. Gallet a , M. Vayssade a , M. Morra b , R. Verhoef c , S. Perrone a , G. Cascardo b , P. Vigneron a , H.A. Schols c , M.-D. Nagel a, * a UMR CNRS 6600, Biome ´canique et Bioinge ´ nierie, Universite ´ de Technologie de Compie `gne, BP 20529, 60205 Compie `gne Cedex, France b Nobil Bio Ricerche srl, V. Valcastellana 26, 14037 Portacomaro (AT), Italy c Wageningen University, Department of Agrotechnology and Food Sciences, Laboratory of Food Chemistry, P.O. Box 8129, 6700 EV Wageningen, The Netherlands Received 18 November 2008; received in revised form 10 March 2009; accepted 24 March 2009 Available online 31 March 2009 Abstract The surface of an implant device can be modified by immobilizing biological molecules on it to improve its integration into the host tissue. We have previously demonstrated that enzymatically tailored plant pectins are promising nanocoatings for biomaterials. This study investigates whether a coating of modified hairy region (rhamnogalacturonan-I) from apple pectin (MHR-a) which has anti-adhe- sive properties can inhibit the generation of inflammatory mediators by lipopolysaccharide (LPS)-activated macrophages. For that pur- pose, J774.2 murine macrophages were cultured for 24 h on MHR-a-coated Petri dishes and tissue culture polystyrene controls, with and without LPS. Cell morphology, cell growth, nitrite and TNF-a secretion were studied. The results indicate that MHR-a coating inhibits the LPS-induced activation of macrophages. Ó 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Pectin-modified hairy region; Pectin-grafted biomaterials 1. Introduction The surface properties of biomaterials trigger extracellu- lar signals that modulate the behaviour of adherent cells. The integration of an implant into host tissue can be improved by modifying the surface of the implanted device by immobilizing biological molecules on it [1]. We have previously shown [2] that enzymatically tailored plant pec- tins (differing in charge, molecular weight, degree of branching and acetylation) can be used as nanocoatings to improve the biocompatibility of biomaterials and medi- cal devices. The pectins are complex polysaccharides that have ‘‘smooth” and ‘‘hairy” regions. The smooth region is made up of homogalacturonan (HGA) and optionally xylogalac- turonan. They both have a (1?4)-a-D-GalpA backbone and can be methyl-esterified. In addition, HGA may be par- tially O-acetylated at the O-3 or O-2 position of the GalA moieties [3,4]. The hairy region (HR) consists of rhamnoga- lacturonan-I (RG-I), which has a backbone of ?2)-a-L- Rhap-(1?4)-a-D-GalpA-(1? repeats branched at the O-4 position of the rhamnose moiety [5,6]. Techniques for tailor- ing side chain structures in vitro by specific enzymes are well established [7]. Commercial pectinase preparations can be used to liquefy fruit and vegetable tissues and then isolate RG-I-rich fractions on a pilot scale [8,9]. The enzymes degrade the HGA part (smooth regions) of the pectin, leav- ing the HR intact. We have previously shown that immobi- lized modified hairy regions (MHRs) of pectin influence the morphology, adhesion, cell cycle progression and sur- vival of fibroblasts [10]. Numerous studies have shown that pectic polysaccharides are potentially important immuno- modulatory agents that may, for example, increase the 1742-7061/$ - see front matter Ó 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.actbio.2009.03.031 * Corresponding author. Tel.: +33 3 44 23 44 21; fax: +33 3 44 20 79 42. E-mail address: marie-danielle.nagel@utc.fr (M.-D. Nagel). Available online at www.sciencedirect.com Acta Biomaterialia 5 (2009) 2618–2622 www.elsevier.com/locate/actabiomat