Selective Alzheimer's disease (AD) indicator-1 (Seladin-1) gene has been identified as a gene, whose expression is down-regulated in the vulnerable region in the brain of AD patients. Thyroid hormone (TH) is important to maintain the function of central nervous system and TH receptor (TR) is known to crosstalk with liver X receptor (LXR) on the lipid metabolism-related gene promoter. Recently, we have demonstrated that TR-beta up-regulates the mouse Seladin-1 gene promoter at the transcriptional levels and LXR-alpha compensates the promoter activation only when the thyroid function is insufficient. In the current study, we have identified that TH and an LXR artificial agonist, TO901317 (TO) activated the human Seladin-1 promoter (-1024/+57 base pair (bp)) including consensus TH response element (TRE) half site (site A: -381 to -375 bp), and the site A mutation deteriorated the activation by TH and TO. Both TR-beta and LXR-alpha heterodimerize with retinoid X receptor (RXR)-alpha on the site A, and chromatin immunoprecipitation (ChIP) assay revealed that TR-beta, LXR-alpha and RXR-alpha are recruited to the site A. Moreover, TR-beta and LXR-alpha functionally compete for the promoter activation in CV1 cells. Taken together, we concluded that TR-beta and LXR-alpha competitively up-regulate the human Seladin-1 promoter, sharing the same response element, site A. (C) 2013 Elsevier Inc. All rights reserved.