The absence of Klotho (KL) in mice causes the development of disorders associated with human aging and decreased longevity, while increased expression prolongs lifespan. With age, KL protein levels decrease and keeping levels consistent may promote healthier aging and be disease modifying.

Using the KL promoter to drive expression of luciferase, we conducted a high throughput screen to identify compounds that activate KL transcription. Hits were identified as compounds elevating luciferase expression at least 30%. Following validation for dose-dependent activation and lack of cytotoxicity, hit compounds were further evaluated in vitro by incubation with opossum kidney and Z310 rat choroid plexus cells, which express KL endogenously. All compounds elevated KL protein compared to control.

To determine whether increased protein resulted in an in vitro functional change, scientists assayed FGF23 signaling. Compounds G-I augmented ERK phosphorylation in FGFR transfected cells, while co-transfection with KL siRNA blocked the effect. These compounds will be useful tools to allow insight into the mechanisms of KL regulation.