Inhaled CD86 antisense oligonucleotide suppresses pulmonary inflammation and airway hyper-responsiveness in allergic mice.

The B7-family molecule CD86, expressed on the surface of pulmonary and thoracic lymph node antigen-presenting cells, delivers essential costimulatory signals for T-cell activation in response to inhaled allergens. CD86-CD28 signaling is involved in priming allergen-specific T cells, but it is unclear whether these interactions play a role in coordinating memory T-helper 2 cell responses. In the ovalbumin (OVA)-induced mouse model of asthma, administration of CD86-specific antibody before systemic sensitization suppresses inhaled OVA-induced pulmonary inflammation and airway hyper-responsiveness (AHR). In previously OVA-sensitized mice, systemic and intranasal coadministration of CD86 antibody is required to produce these effects. To directly assess the importance of pulmonary CD86 expression in secondary immune responses to inhaled allergens, mice were sensitized and locally challenged with nebulized OVA before treatment with an inhaled aerosolized CD86 antisense oligonucleotide (ASO). CD86 ASO treatment suppressed OVA-induced up-regulation of CD86 protein expression on pulmonary dendritic cells and macrophages as well as on recruited eosinophils. Suppression of CD86 protein expression correlated with decreased methacholine-induced AHR, airway inflammation, and mucus production following rechallenge with inhaled OVA. CD86 ASO treatment reduced BAL eotaxin levels, but it did not reduce CD86 protein on cells in the draining lymph nodes of the lung, and it had no effect on serum IgE levels, suggesting a local and not a systemic effect. These results demonstrate that CD86 expression on pulmonary antigen-presenting cells plays a vital role in regulating pulmonary secondary immune responses and suggest that treatment with an inhaled CD86 ASO may have utility in asthma and other chronic inflammatory lung conditions.

Antisense oligonucleotide inhibition of Bcl-xL and Bid expression in liver regulates responses in a mouse model of Fas-induced fulminant hepatitis.

Activation of the cell-surface receptor Fas can lead to apoptosis in parenchymal cells in the liver, and if severe enough, result in fulminant hepatic failure and animal death. In the present study, we have examined the roles played by the Bcl-2 family members Bcl-xL and Bid in regulating this response. To do this, we have developed chemically modified 2'-O-(2-methoxy) ethyl antisense inhibitors of both Bid and Bcl-xL expression. In Balb/c mice, dosing with these antisense oligonucleotides reduced expression of the targeted mRNA by greater than 80% in the liver. This reduction was highly dependent upon oligonucleotide sequence and oligonucleotide dose. Reduction of Bcl-xL expression resulted in a potentiation of Fas-mediated apoptosis in liver and significant increase of the lethality of Fas-mediated fulminant hepatitis (p < 0.0001). In contrast, reduction of Bid expression protected the animals against Fas-mediated fulminant hepatitis and death (p < 0.0001). Simultaneous dosing of mice with Bcl-xL and Bid-targeting antisense oligonucleotides resulted in an inhibition of expression of both targeted proteins and protection of the animals from Fas-mediated apoptosis. These results demonstrate, for the first time, the role of Bcl-xL in regulating responses to proapoptotic Fas signaling in mouse liver. In addition, this is the first reported example demonstrating the ability of antisense inhibitors to reduce expression of multiple proteins in animals by simultaneous dosing.