Induction of human and murine hepatic hydroxysteroid sulfotransferase gene expression by RNA interference‐mediated knock‐down of PAPS synthase 2

Abstract

Hydroxysteroid sulfotransferase (SULT2A) catalyzes the transfer of sulfate from the physiological sulfate donor 3′‐phosphoadenosine‐5′‐phosphosulfate (PAPS) to endogenous and xenobiotic substrates. In human hepatocytes, PAPS synthesis is catalyzed by PAPS synthase 2 (PAPSS2). HepG2 cells were stably transduced with lentivirus expressing either non‐targeting small interfering RNA (siRNA) (siNT‐HepG2) or siRNA directed against PAPS synthase 2 (siPAPSS2‐HepG2). Relative to siNT‐HepG2, siPAPSS2‐HepG2 cells transiently transfected with a reporter plasmid containing 1.5 kb of a murine SULT2A 5′‐flanking region demonstrated a significant (~2‐fold) increase in reporter expression. Disruption of a putative LXR motif in the murine SULT2A 5′‐flanking region suppressed the induction of SULT2A reporter expression produced by PAPSS2 knock‐down. Real‐time RT‐PCR analysis also demonstrated ~3‐fold induction of endogenous human SULT2A1 mRNA expression by PAPSS2 knock‐down. These results indicate that both human and murine SULT2A transcription are up‐regulated in response to PAPSS2 knock‐down, and implicate a role for LXR as a sulfate sensor. Supported by ES058223 (M.R.M.), HL50710 (T.A.K) and ES06636.