NF-KAPPA-B AS A TARGET FOR ANTIINFLAMMATORY GENE-THERAPY - SUPPRESSION OF INFLAMMATORY RESPONSES IN MONOCYTIC AND STROMAL CELLS BY STABLE GENE-TRANSFER OF I-KAPPA-B-ALPHA CDNA

One of the most challenging issues of anti-inflammatory gene therapy i s the complexity of inflammatory pathways. Transcription factor NF-kap pa B plays a pivotal role in activation of multiple inflammatory molec ules, and therefore represents the logical target for intervention. We evaluated the feasibility of suppressing the inflammatory responses i n different cell lines through specific inhibition of NF-kappa B by ge ne transfer of I kappa B alpha, the naturally occurring intracellular inhibitor of NF-kappa B. The I kappa B alpha overexpressing cells were established using retroviral gene transfer or stable transfection wit h the wild-type (wt) I kappa B alpha cDNA. In all cell types, overexpr ession of wt I kappa B alpha resulted in a profound (> 100-fold) incre ase of the I kappa B alpha message and a moderate (two- to three-fold) increase of the I kappa B alpha protein. the effects of the I kappa B alpha overexpression on the NF-kappa B activation and the inflammator y responses varied significantly in different cell lines. In condition ally immortalized human endometrial stromal cells, overexpression of I kappa B alpha prevented both interleukin-1 (IL-1)-inducible degradati on of endogenous I kappa B alpha protein and activation of NF-kappa B. Accordingly, induction of cytokines interleukin-8 (IL-8) and Gro gamm a was markedly suppressed. In monocytic THP-1 cells, both lipopolysacc haride (LPS)-inducible degradation of I kappa B alpha and NF-kappa B a ctivation were only partially inhibited by overexpression of exogenous I kappa B alpha cDNA. None the less, the LPS-induced transcription of IL-1 beta and secretion of cytokines interleukin-6 (IL-6) and IL-8 we re virtually abolished. In epithelial HT-29 cells, no inflammatory res ponses were inhibited. These results demonstrate the range of response s in various cell lines to gene transfer of I kappa B alpha and indica te the feasibility of suppression of inflammatory responses in appropr iate target cells and their progeny by suppression of NF-kappa B.