Short Term Regulation of SGLT2 by Insulin in vivo

• DOI: 10.1096/fasebj.30.1_supplement.967.16
• Publication Date: 2023-11-26T16:23:51Z
• Authors: Chiara Ghezzi; Claudio Scafoglio; Jie Liu; Jorge R Barrio; Ernest M Wright

Glucose homeostasis is a complex mechanism that requires the interplay between different organs. The kidney plays a central role in this process by re‐absorbing 99.5% of the filtered glucose in the proximal tubules, where SGLT1 and SGLT2 use the energy provided by the electrochemical gradient of sodium to drive glucose transport.In recent years SGLT2 has received much attention as the target of inhibition by a class of drugs (i.e. dapagliflozin, canagliflozin) that lower blood glucose levels in type II diabetes patients by blocking glucose re‐absorption in the kidney tubules. In the present study, we used [F‐18] fluoro‐dapagliflozin (F‐Dapa), a specific, high‐affinity SGLT2 ligand (KB 4 nM), to study the localization and activity of SGLT2 in the mouse kidney in vivo, by microPET on wild type (WT) and knock‐out mice.Our results showed, as expected, that in WT mice SGLT2 was highly expressed in the kidney. Binding was fast and reached saturation already after 10 minutes. The specificity of F‐Dapa binding was determined using SGLT2−/− and SGLT1−/−‐SGLT2−/− mice, in which binding was reduced to background levels, and competition experiments with phlorizin and dapagliflozin, in which we observed the blockage of F‐Dapa binding and the displacement of the bound ligand.We have previously shown that hSGLT2 expressed in HEK‐293T cells is up‐regulated by insulin due to either a fast insertion of an intracellular pool of transporters into the plasma membrane, or an increase in the transporter catalytic turnover. To determine the effect of insulin on SGLT2 in vivo, we measured the change in F‐Dapa binding to the kidney after insulin injection. Our results showed that immediately after insulin administration, F‐Dapa binding rapidly increased by 30% to a new steady state, and the total binding was displaced by dapagliflozin and phlorizin.In conclusion, our results showed that F‐Dapa is a SGLT2‐specific tracer that can be used to study the protein localization to the brush border membrane of the proximal tubule in vivo. Moreover, using this tool we showed that insulin rapidly recruits an intracellular pool of SGLT2 to the brush border membrane.Support or Funding InformationNIH/NIDDKDK077133