Effect of antisense oligonucleotides on TNF-alpha synthesis in macrophages

The impact of Kupffer cell-derived cytokines outside the liver during the u nspecific immune response has not yet been elucidated. To abolish cytokine expression specifically in these liver cells, antisense oligo-deoxyribonucl eotides (oligos) directed towards TNF-alpha mRNA were tested for their abil ity to inhibit TNF-alpha release. Employment of carriers with high affinity to Kupffer cell-specific receptors should address the oligos to these cell s. Using FITC-labeled phosphorothioate 21-mer oligos tailored against the star t region of pro-TNF-alpha synthesis, uptake, stability and biological effic iency could be demonstrated in the macrophage cell line P388D1. Anionic or cationic carriers including various liposomes did not improve significantly these performances. The inclusion of oxidized low-density lipoprotein to d irect the liposomes preferentially to the Kupffer cells failed because of t he toxicity of oxLDL for the macrophages. In contrast to the P388D1 cells, rat Kupffer cells degraded the oligos rapi dly; an intracellular concentration sufficient for suppression of TNF-alpha synthesis could not be achieved.