Regulation of Na+/glucose cotransporter (SGLT1) mRNA in LLC-PK1 cells

✍ Scribed by Shaw-Fang Yet; Cheng-Te Kong; Hua Peng; Julia E. Lever

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 805 KB
• Volume: 158
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041580315

✦ Synopsis

The porcine kidney epithelial cell line LLC-PK, expresses a sodium-coupled glucose cotransporter (SGLTI) together with other differentiation markers of renal proximal tubule such as trehalase and y-glutamyltranspeptidase. Expression is regulated by cell density and exogenous differentiation inducers such as hexamcthylene bisacetaniide {HMBA). Northern blot and PCR analysis of clonal cell populations indicated SGLTl mRNA was not detectable in subconfluent cultures, but 2.2 and 3.9 kb SGLTl mRNA species appeared after cell confluence, accompanying expression of the transport activity. SGLTl mRNA levels were significantly increased after treatment of confluent cultures with HMBA, paralleling increases in the transport activity and irnmunodetectable 75 kD cotransporter subunit. SCLTl mRNA was also increased after treatment of cultures with the cyclic AMP phosphodiesterase inhibitor 3-isobutyl-I -methylxanthine (IBMX), an inducer of Na+/glucose cotransport activity. The 3.9 kb SCLTl transcript showed the largest increase after either HMBA or IBMX treatment. HMBA treatment also resulted in increased mRNA levels of two other differentiation markers-trehalase and y-glutamyltranspeptidase. By contrast, trehalase and y-glutamyltranspeptidase mRNA levels were not increased by IBMX. Regulation of Na+/glucose symporter expression by either cell density, cyclic AMP elevation, or differentiation inducer treatment occurs, at least in part, at the level of SGLTl mRNA and can be dissociated from regulation of other differentiation markers.