Journal: Journal of molecular and cellular cardiology
Article Title: SGLT1, a Novel Cardiac Glucose Transporter, Mediates Increased Glucose Uptake in PRKAG2 Cardiomyopathy
Figure Lengend Snippet: Cardiac GLUT1, GLUT4, and SGLT1 mRNA and protein expression in TG T400N mice. (A) Total cardiac GLUT1 and GLUT4 transcript expression, as assessed by QPCR, were similar in TG T400N mice and WT littermates at ages 2 and 8 weeks, whereas cardiac SGLT1 transcript expression was increased in TG T400N mice at ages 2 and 8 weeks ( n = 3 / group). (B) In whole heart homogenates, densitometry analysis of immunoblots showed that GLUT1 protein was significantly increased, GLUT4 protein was significantly decreased, and SGLT1 protein was unchanged in TG T400N mice relative to WT littermates at ages 2 and 8 weeks. (C) In total membrane extracts, densitometry analysis of immunoblots showed that GLUT1 and GLUT4 protein expression was not significantly different in TG T400N mice relative to WT littermates at ages 2 and 8 weeks, whereas SGLT1 protein expression was significantly increased in TG T400N mice at ages 2 and 8 weeks. (D) In sarcolemmal membrane extracts, GLUT1 and SGLT1 protein expression appeared to be mildly increased at age 2 weeks and greatly increased at age 8 weeks in TG T400N mice relative to WT littermates, whereas there was no apparent difference in GLUT4 expression ( n = 10 − 12 / group, pooled into one lane). The α1 subunit of the Na + /K + -ATPase, a sarcolemmal membrane marker, was used to document adequate enrichment of membrane fractions. (E)Immunofluorescence microscopy showed that SGLT1 (green) had similar subcellular distributions in WT and TG T400N cardiac myocytes at ages 2 and 8 weeks. (F) Immunofluorescence microscopy showed that α-subunit Na + /K + -ATPase (green, upper panel) and SGLT1 (red, middle panel) partially co-localized (lower panel) with in cardiac myocytes from 8 week old WT and TG T400N mice. (G) Control incubations were performed with secondary antibody only (“no-primary” control) and with nonspecific primary antibody, and showed no immunofluorescence labeling under identical acquisition conditions. Open bars, WT; closed bars, TG T400N . T, TG T400N ; W, WT. Molecular weights (MW) on immunoblots were estimated by protein marker sizes. Coomassie blue staining was used to document the relative quantity of protein loaded for the immunoblots and to normalize densitometry analysis. Scale bars on photomicrographs represent 37.5 μm. *, P
Article Snippet: Thus, there may be differences between acute and chronic AMPK regulation of SGLT1, and differences among tissues, cell types, and possibly species.
Techniques: Expressing, Mouse Assay, Real-time Polymerase Chain Reaction, Western Blot, Marker, Microscopy, Immunofluorescence, Labeling, Staining