Polyelectrolyte multilayer films modulate cytoskeletal organization in chondrosarcoma cells.

The aim of this study was to evaluate polyelectrolyte multilayer films as interfaces for implants. Polyelectrolyte multilayers were built up with different terminating layers by alternate deposition of oppositely charged polyelectrolytes on which chondrosarcoma (HCS-2/8) cells were grown in the presence of serum. Films formed by an increasing number of layers were investigated. The terminating layer was made of one of the following polyelectrolytes: poly-sodium-4-styrenesulfonate (PSS), poly-L-glutamic acid (PGA), poly-allylamine hydrochloride (PAH), or poly(L-lysine) (PLL). Cell viability, inflammatory response, adherence, and cytoskeletal organization were studied. Induction of interleukin-8 (IL-8) secretion was detected on PAH and PLL ending polyelectrolyte films. Early cellular adherence was enhanced with PGA, PAH, PLL, and, to a lower extent, PSS terminating layers. Adherence was independent of the number of layers constituting the films. The presence of actin filaments and vinculin focal adhesion spots was observed on PSS or PAH ending films. They were respectively partially and totally absent on PGA and PLL terminating multilayer architectures. For PLL ending films, vinculin and actin organization was clearly dependent on the number of deposited layers. The results of this study suggest that PSS ending multilayered films constitute a good interfacial micro-environment at the material surface for HCS-2/8 cells.

Reduction of macrophage activation after antioxidant enzymes gene transfer to rat insulinoma INS-1 cells.

BACKGROUND: After transplantation, islet damage occurs through oxidative stress and host immune rejection mediated in part by macrophage activation. We investigated the influence of the overexpression of catalase (CAT) and Cu/Zn superoxide dismutase (Cu/Zn SOD) by rat insulinoma INS-1 beta cells exposed to oxidative stress on their viability and murine macrophage activation. METHODS: INS-1 cells were infected with adenoviral vectors containing CAT (AdCAT) or Cu/Zn SOD (AdSOD) genes. After 72 hours, noninfected and infected INS-1 cells were exposed to oxidative stress and their viability was assessed using a colorimetric assay. Murine peritoneal exudate macrophages (mPEM) incubated with the supernatant of infected and stressed INS-1 cells were tested for chemotaxis and cytokine release (TNF-alpha, IL-alpha and IFN-gamma). RESULTS: After infection, AdCAT and AdSOD gene transfer protected INS-1 cells from the toxicity of different oxidative reagents. The exposure of non-infected INS-1 cells to oxidative stress stimulated mPEM chemotaxis. INS-1 cells infection with AdCAT or AdSOD reduced significantly mPEM chemotaxis from 2.41 +/- 0.31 to 1.61 +/- 0.17 and from 2.53 +/- 0.24 to 1.27 +/- 0.14 respectively (n = 5; p < 0.05). Cytokine release by mPEM was stimulated after exposure to stressed noninfected INS-1 cell supernatant. CAT and Cu/Zn SOD overexpression by infected INS-1 cells decreased significantly the release of TNF-alpha from 268.18 +/- 30.18 to 81.40 +/- 23.58 pg/ml and from 446.96 +/- 75.47 to 20.37 +/- 2.38 pg/ml respectively (n = 6; p < 0.001). The overexpression of these enzymes also reduced significantly the release of IL-1beta and IFN-gamma. CONCLUSIONS: CAT or Cu/Zn SOD gene transfer to INS-1 cells preserved them from oxidative damage and reduced the macrophage activation induced by these pancreatic cells. Therefore, protection of pancreatic beta cells against oxidative injury by antioxidant enzymes gene transfer is an effective approach to overcome the deleterious actions of macrophages in pancreatic islet transplantation.