title: Neprilysin is a Mediator of Alternative Renin-Angiotensin-System Activation in the Murine and Human Kidney.
abstract: Cardiovascular and renal pathologies are frequently associated with an activated renin-angiotensin-system (RAS) and increased levels of its main effector and vasoconstrictor hormone angiotensin II (Ang II). Angiotensin-converting-enzyme-2 (ACE2) has been described as a crucial enzymatic player in shifting the RAS towards its so-called alternative vasodilative and reno-protective axis by enzymatically converting Ang II to angiotensin-(1-7) (Ang-(1-7)). Yet, the relative contribution of ACE2 to Ang-(1-7) formation in vivo has not been elucidated. Mass spectrometry based quantification of angiotensin metabolites in the kidney and plasma of ACE2 KO mice surprisingly revealed an increase in Ang-(1-7), suggesting additional pathways to be responsible for alternative RAS activation in vivo. Following assessment of angiotensin metabolism in kidney homogenates, we identified neprilysin (NEP) to be a major source of renal Ang-(1-7) in mice and humans. These findings were supported by MALDI imaging, showing NEP mediated Ang-(1-7) formation in whole kidney cryo-sections in mice. Finally, pharmacologic inhibition of NEP resulted in strongly decreased Ang-(1-7) levels in murine kidneys. This unexpected new role of NEP may have implications for the combination therapy with NEP-inhibitors and angiotensin-receptor-blockade, which has been shown being a promising therapeutic approach for heart failure therapy.
authors.affiliation: Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Domenig
authors.affiliation: Department of Neurology, University Hospital Erlangen, Erlangen, Germany.
authors.forename: Arndt
authors.initials: A
authors.lastname: Manzel
authors.affiliation: Department of Pharmacology and Toxicology, Wright State University, OH, USA.
authors.forename: Nadja
authors.initials: N
authors.lastname: Grobe
authors.affiliation: Department of Nephrology, Medical Faculty, Heinrich Heine University, Duesseldorf, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Königshausen
authors.affiliation: Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Kaltenecker
authors.affiliation: Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Kovarik
authors.affiliation: Department of Nephrology, Medical Faculty, Heinrich Heine University, Duesseldorf, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Stegbauer
authors.affiliation: Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, NC 27710, USA.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Gurley
authors.affiliation: Attoquant Diagnostics GmbH, Vienna, Austria.
authors.forename: Dunja
authors.initials: D
authors.lastname: van Oyen
authors.affiliation: Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Marlies
authors.initials: M
authors.lastname: Antlanger
authors.affiliation: Max-Delbrück-Center for Molecular Medicine (MDC), Berlin-Buch, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Bader
authors.affiliation: Department of Physiology and Biophysics, National Institute of Science and Technology in Nanobiopharmaceutics, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Daisy
authors.initials: D
authors.lastname: Motta-Santos
authors.affiliation: Institute of Cardiology, University Cardiology Foundation, Porto Alegre, RS, Brazil.
authors.forename: Robson A
authors.initials: RA
authors.lastname: Santos
authors.affiliation: Department of Pharmacology and Toxicology, Wright State University, OH, USA.
authors.forename: Khalid M
authors.initials: KM
authors.lastname: Elased
authors.affiliation: Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
authors.forename: Marcus D
authors.initials: MD
authors.lastname: Säemann
authors.affiliation: Department of Neurology, University Hospital Erlangen, Erlangen, Germany.
authors.forename: Ralf A
authors.initials: RA
authors.lastname: Linker
authors.affiliation: Attoquant Diagnostics GmbH, Vienna, Austria.
authors.forename: Marko
authors.initials: M
authors.lastname: Poglitsch
mesh_terms: D000613:Aminobutyrates / Q000494:pharmacology; D000803:Angiotensin I / Q000378:metabolism; D000804:Angiotensin II / Q000235:genetics / Q000378:metabolism; D000085962:Angiotensin-Converting Enzyme 2; D000818:Animals; D015415:Biomarkers; D001706:Biopsy; D001713:Biphenyl Compounds / Q000494:pharmacology; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000502:physiology*; D007672:Kidney Cortex / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D015260:Neprilysin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D007703:Peptidyl-Dipeptidase A / Q000235:genetics / Q000378:metabolism; D012083:Renin / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000502:physiology*
chemical_list: D000613:Aminobutyrates; D015415:Biomarkers; D001713:Biphenyl Compounds; C000609743:LBQ657; D010446:Peptide Fragments; D000804:Angiotensin II; D000803:Angiotensin I; D007703:Peptidyl-Dipeptidase A; C000705307:ACE2 protein, human; C000705328:Ace2 protein, mouse; D000085962:Angiotensin-Converting Enzyme 2; D012083:Renin; D015260:Neprilysin; C118790:angiotensin I (1-7)