Glucose Transporters in Human Renal Proximal Tubular Cells Isolated From the Urine of Patients With Non–Insulin-Dependent Diabetes

Glucose Transporters in Human Renal Proximal Tubular Cells Isolated From the Urine of Patients With Non–Insulin-Dependent Diabetes Hassan Rahmoune , Paul W. Thompson , Joanna M. Ward , Chari D. Smith , Guizhu Hong and John Brown From the Clinical Pharmacology Unit, GlaxoSmithKline, Translational Medicine and Technology, Human Biomarkers Centre, Addenbrooke’s Hospital, Cambridge, U.K Address correspondence and reprint requests to Hassan Rahmoune, PhD, GlaxoSmithKline, Clinical Pharmacology Unit, Human Biomarkers Centre, Translational Medicine and Technology, Addenbrooke’s Hospital, Cambridge, CB2 2GG, U.K. E-mail: hassan_2_rahmoune{at}gsk.com Abstract The bulk of glucose that is filtered by the renal glomerulus is reabsorbed by the glucose transporters of the proximal convoluted tubular epithelium. However, it has been difficult to investigate this in diseases such as type 2 diabetes because of the inability to isolate primary renal cells from patients without a renal biopsy. We report here a method for the immunomagnetic isolation and novel primary culture of human exfoliated proximal tubular epithelial cells (HEPTECs) from fresh urine. The primary isolates are highly enriched and differentiated and express characteristic proximal tubular phenotypic markers. They continue to express the proximal tubular markers CD13/aminopeptidase-N, sodium glucose cotransporter (SGLT) 2, and alkaline phosphatase through up to six subsequent subcultures in a similar way to human proximal cells isolated from renal biopsies. In a hyperglycemic environment, HEPTECs isolated from patients with type 2 diabetes expressed significantly more SGLT2 and the facilitative glucose transporter GLUT2 than cells from healthy individuals. We also demonstrated a markedly increased renal glucose uptake in HEPTECs isolated from patients with type 2 diabetes compared with healthy control subjects. Our findings indicate for the first time in a human cellular model that increased renal glucose transporter expression and activity is associated with type 2 diabetes. AMG, methyl-α-d-[U14C]-glucopyranoside ENaCα, epithelial sodium amiloride–sensitive channel-α FBS, fetal bovine serum FITC, fluorescein isothiocyanate GAPDH, glyceraldehyde-3-phosphate dehydrogenase HEPTEC, human exfoliated proximal tubular epithelial cell PBST, PBS Tween PPAR, peroxisome proliferator–activated receptor SGLT, sodium glucose cotransporter TRITC, tetramethylrhodamine isothiocyanate Footnotes C.D.S. is currently affiliate