The present study investigated transcriptional inactivation of TNF-α gene by nuclear factor-binding oligonucleotides (ON) and their effects on pulmonary inflammatory responses in mice. PCR-based gene mutation and gel shift assays were used to identify specific cis-acting elements necessary for nuclear factor binding and transactivation of TNF-α gene by lipopolysaccharide (LPS). LPS inducibility of TNF-α was shown to require transcriptional activation by NF-κB at multiple binding sites, including the −850 (κ1), −655 (κ2), and −510 (κ3) sites, whereas the −210 (κ4) site had no effect. Maximum inducibility was associated with the activation of κ3 site. The sequence-specific, double-stranded ON targeting this site was most effective in inhibiting TNF-α activity induced by LPS. The inhibitory effect of ON on TNF-α bioactivity was also investigated using a murine lung inflammation model. Pretreatment of mice with ON, but not its mutated sequence, inhibited LPS-induced inflammatory neutrophil influx and TNF-α production by lung cells. Effective inhibition by ON in this model was shown to require a liposomal agent for efficient cellular delivery of the ON. Together, our results indicate that transcriptional inactivation of TNF-α gene can be achieved by using ON that compete for nuclear factor binding to TNF-α gene promoter. This gene inhibition approach may be used as a research tool or as potential therapeutic modality for diseases with etiology dependent on aberrant gene expression.
A Cohesin-Based Partitioning Mechanism Revealed upon Transcriptional Inactivation of Centromere
