Selective Pharmaceutical Inhibition of PARP14 Mitigates Allergen-Induced IgE and Mucus Overproduction in a Mouse Model of Pulmonary Allergic Response.

The type 2 cytokines IL-4 and IL-13, which share use of an IL-4 receptor α-chain and its nuclear induction of the transcription factor STAT6, are crucial in elicitation and maintenance of allergic conditions including asthma. STAT6 binds poly(ADP-ribose) polymerase (PARP)14, an ADP-ribosyl monotransferase. Elimination of PARP14 by gene targeting led to attenuation of OVA-specific allergic lung inflammation. However, PARP14 has multiple functional domains apart from the portion that catalyzes ADP-ribosylation, and it is not clear whether inhibition of the catalytic function has any biological consequence. Using BALB/c mice sensitized to the allergen Alternaria alternata, we show that peroral administration of RBN012759, a highly selective inhibitor of ADP-ribosylation by PARP14 with negligible impact on other members of the PARP gene family, achieved biologically active plasma concentrations and altered several responses to the Ag. Specifically, the pharmaceutical compound decreased mucus after allergen challenge, blunted the induced increases in circulating IgE, and prevented suppression of IgG2a. We conclude that PARP14 catalytic activity can contribute to pathogenesis in allergic or atopic processes and propose that other biological endpoints dependent on ADP-ribosylation by PARP14 can be targeted using selective inhibition.