title: Regulation of urinary ACE2 in diabetic mice.
abstract: Angiotensin-converting enzyme-2 (ACE2) enhances the degradation of ANG II and its expression is altered in diabetic kidneys, but the regulation of this enzyme in the urine is unknown. Urinary ACE2 was studied in the db/db model of type 2 diabetes and stretozotocin (STZ)-induced type 1 diabetes during several physiological and pharmacological interventions. ACE2 activity in db/db mice was increased in the serum and to a much greater extent in the urine compared with db/m controls. Neither a specific ANG II blocker, telmisartan, nor an ACE inhibitor, captopril, altered the levels of urinary ACE2 in db/db or db/m control mice. High-salt diet (8%) increased whereas low-salt diet (0.1%) decreased urinary ACE2 activity in the urine of db/db mice. In STZ mice, urinary ACE2 was also increased, and insulin decreased it partly but significantly after several weeks of administration. The increase in urinary ACE2 activity in db/db mice reflected an increase in enzymatically active protein with two bands identified of molecular size at 110 and 75 kDa and was associated with an increase in kidney cortex ACE2 protein at 110 kDa but not at 75 kDa. ACE2 activity was increased in isolated tubular preparations but not in glomeruli from db/db mice. Administration of soluble recombinant ACE2 to db/m and db/db mice resulted in a marked increase in serum ACE2 activity, but no gain in ACE2 activity was detectable in the urine, further demonstrating that urinary ACE2 is of kidney origin. Increased urinary ACE2 was associated with more efficient degradation of exogenous ANG II (10(-9) M) in urine from db/db compared with that from db/m mice. Urinary ACE2 could be a potential biomarker of increased metabolism of ANG II in diabetic kidney disease.
authors.affiliation: Div. of Nephrology and Hypertension, Dept. of Medicine, The Feinberg School of Medicine, Northwestern Univ., 320 E. Superior, Chicago, IL 60611. d-batlle@northwestern.edu.
authors.forename: Jan
authors.initials: J
authors.lastname: Wysocki
authors.forename: Laura
authors.initials: L
authors.lastname: Garcia-Halpin
authors.forename: Minghao
authors.initials: M
authors.lastname: Ye
authors.forename: Christoph
authors.initials: C
authors.lastname: Maier
authors.forename: Kurt
authors.initials: K
authors.lastname: Sowers
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Burns
authors.forename: Daniel
authors.initials: D
authors.lastname: Batlle
mesh_terms: D000804:Angiotensin II / Q000378:metabolism*; D000085962:Angiotensin-Converting Enzyme 2; D000818:Animals; D015415:Biomarkers / Q000378:metabolism / Q000652:urine; D015153:Blotting, Western; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism; D003928:Diabetic Nephropathies / Q000378:metabolism* / Q000652:urine*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism* / Q000652:urine*
chemical_list: D015415:Biomarkers; D000804:Angiotensin II; D007703:Peptidyl-Dipeptidase A; C000705328:Ace2 protein, mouse; D000085962:Angiotensin-Converting Enzyme 2
keywords: angiotensin-converting enzyme 2; biomarker; diabetes; nephropathy; urinary