The toxic amyloid beta-peptide (A beta) is a key player in Alzheimer Disease (AD) pathogenesis and selective inhibition of the production of this peptide is sought for. A beta is produced by the sequential cleavage of the A beta precursor protein (APP) by beta-secretase (to yield APP-C-terminal fragment beta (APP-CTF beta) and soluble APPb (sAPPb)) and gamma-secretase (to yield A beta). We reasoned that proteins that associate with gamma-secretase are likely to regulate A beta production and to be targets of pharmaceutical interventions and therefore performed a pull-down assay to screen for such proteins in rat brain. Interestingly, one of the purified proteins was potassium/sodium hyperpolarization-activated cyclic nucleotide-gated ion channel 2 (HCN2), which has been shown to be involved in epilepsy. We found that silencing of HCN2 resulted in decreased secreted A beta levels. To further investigate the mechanism behind this reduction, we also determined the levels of full-length APP, sAPP and APP-CTF species after silencing of HCN2. A marked reduction in sAPP and APP-CTF, as well as glycosylated APP levels was detected. Decreased A beta, sAPP and APP-CTF levels were also detected after treatment with the HCN2 inhibitor ZD7288. These results indicate that the effect on A beta levels after HCN2 silencing or inhibition is due to altered APP maturation or processing by beta-secretase rather than a direct effect on gamma-secretase. However, HCN2 and gamma-secretase were found to be in close proximity, as evident by proximity ligation assay and immunoprecipitation. In summary, our results indicate that silencing or inhibition of HCN2 affects APP processing and thereby could serve as a potential treatment strategy. (C) 2016 Elsevier Inc. All rights reserved.