Identification of novel small molecules that elevate Klotho expression

Abstract

The absence of Klotho (KL) from mice causes the development of disorders associated with human aging and decreased longevity, whereas 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 that elevated luciferase expression at least 30%. Following validation for dose-dependent activation and lack of cytotoxicity, hit compounds were evaluated further in vitro by incubation with opossum kidney and Z310 rat choroid plexus cells, which express KL endogenously. All compounds elevated KL protein compared with control. To determine whether increased protein resulted in an in vitro functional change, we assayed FGF23 (fibroblast growth factor 23) signalling. Compounds G–I augmented ERK (extracellular-signal-regulated kinase) phosphorylation in FGFR (fibroblast growth factor receptor)-transfected cells, whereas co-transfection with KL siRNA (small interfering RNA) blocked the effect. These compounds will be useful tools to allow insight into the mechanisms of KL regulation. Further optimization will provide pharmacological tools for in vivo studies of KL.

Life Extension Factor Klotho Prevents Mortality and Enhances Cognition in hAPP Transgenic Mice

“…Our study revealed that the function of NMDARs, which is critical for normal cognition and impaired by A␤ and tau (Nakazawa et al, 2004;Lee and Silva, 2009;Hoover et al, 2010;Ittner et al, 2010;Cissé et al, 2011;Li et al, 2011), represents a potential convergence point at which klotho may counteract the adverse effects of these pathogens. Klotho elevation prevented the depletion of NMDAR subunits GluN1, GluN2A, and GluN2B and ameliorated impairments of NMDAR-dependent synaptic plasticity in the hippocampus of hAPP mice.…”

“…Hippocampus was dissected, homogenized, and sonicated in ice-cold lysis buffer [1ϫ PBS, pH 7.4, 1 mM DTT, 0.5 mM EDTA, 0.5% Triton, 0.1 M PMSF, protease inhibitor mixture (Roche), and phosphatase inhibitors 2 and 3 (Sigma-Aldrich)]. Following the addition of guanidine (final concentration 5 M), samples were rehomogenized and analyzed for levels of human A␤ 1-x and A␤ 1-42 by ELISA as described previously (Johnson-Wood et al, 1997;.…”

“…Klotho elevation alters NMDAR, but not AMPAR, subunit levels in hAPP mice NMDAR and AMPA receptor (AMPAR) functions are essential to learning and memory (Nakazawa et al, 2004;Lee and Silva, 2009) and disrupted by A␤ (Hsieh et al, 2006;D'Amelio et al, 2011;Li et al, 2011;Chang et al, 2012;Huang and Mucke, 2012). We therefore examined whether klotho elevation modulates these receptors.…”

The Neuroprotective Effect of Klotho is Mediated via Regulation of Members of the Redox System

“…Furthermore, our results reveal that Klotho exerts its neuroprotective effect via the Trx/Prx antioxidative system, which is important for regulating the redox balance in the brain. Finally, our studies suggest that Klotho-enhancing compounds may provide future therapeutic approaches for neurodegenerative disorders (90,91).…”

Klotho Gene, Aging and DNA Methylation

“…Tümör baskılayıcı genlerin DNMT enzimleri ile epigenetik olarak anlatım düzeylerinin düşürülmesi ya da inaktivasyonu kanser gelişiminde önemli bir etken olarak karşımıza çık-maktadır (72). Çeşitli kanser türleri ile ilişkilendirilen ve eksikliğinde yaşlanmaya benzer belirtilerin ortaya çıkmasına neden olan Kl proteininin sentezinin regüle edilmesi bir kısım hastalıkların tedavisine olanak sağlayabilir (73)(74)(75).…”