In vivo evaluation of a morpholino antisense oligomer directed against tumor necrosis factor-alpha

Morpholino antisense oligomers directed against the cytokine tumor necrosis factor (TNF-alpha) can specifically inhibit production of TNF-alpha by mac rophages in vitro. To evaluate the efficacy of morpholino antisense in vivo , we characterized a mouse model of increased pulmonary TNF-alpha productio n and inflammation in response to aerosolized endotoxin. Pretreatment of mi ce by intranasal (i.n.) insufflation of oligomers (30 mu l of 100 mu M/ml) 12 hours prior to lipopolysaccharide (LPS) exposure resulted in specific an d consistent inhibition of TNF-alpha production by the oligomer MAS-2, wher eas no effect was observed with a sequence-scrambled control (% inhibition 31.5 +/- 3.5 vs. 1.3 +/- 8.0, respectively, p < 0.005). Dose-response analy sis showed similar efficacy for MAS-2 at 25-100 mu M/ml and diminished effe cts with lower concentrations. Inhibition of TNF-alpha did not alter the in crease in neutrophils seen in bronchoalveolar lavage (BAL) fluid, a result consistent with observations using i.n. administration of neutralizing anti -TNF-alpha antibody or TNF receptor knockout mice. The results establish th at morpholino oligomers directed against cytokine targets can function in v ivo. Additional studies of other targets and administration protocols to im prove efficacy are warranted.