Expression of angiotensin I-converting enzymes and bradykinin B2 receptors in mouse inner medullary-collecting duct cells.
We described in mouse inner medullary-collecting duct cells (mIMCD-3) the somatic and the N-domain ACE synthesis and its interaction with the kallikrein-kinin system co-localized in the same cells. We purified two ACE forms from culture medium, M1 (130 kDa) and M2 (N-domain, 60 kDa), and cellular lysate, C1 (130 kDa) and C2 (N-domain, 60 kDa). Captopril and enalaprilat inhibited the purified enzymes. The immunofluorescence studies indicated that ACE is present in the membrane, cytoplasm and in the cell nucleus. Kinin B1 and B2 receptors were detected by immunofluorescence and showed to be activated by BK and DesR9 BK, increasing the acidification rate which was enhanced in the presence of enalaprilat. The presence of secreted and intracellular ACE in mIMCD-3 confirmed the hypothesis previously proposed by our group for a new site of ACE secretion in the collecting duct.
Redublo Quinto
Beata Marie
BM
Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Medicina, Disciplina de Nefrologia, 04023-900, São Paulo, SP, Brazil.
Camargo de Andrade
Maria Claudina
MC
Ronchi
Fernanda Aparecida
FA
Santos
Edson Lucas
EL
Alves Correa
Silvana Aparecida
SA
Shimuta
Suma Imura
SI
Pesquero
João Bosco
JB
Mortara
Renato Arruda
RA
Casarini
Dulce Elena
DE
D000818:Animals; D002216:Captopril / Q000494:pharmacology; D002478:Cells, Cultured; D015773:Enalaprilat / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D007679:Kidney Medulla / Q000201:enzymology*; D007685:Kidney Tubules, Collecting / Q000201:enzymology*; D051379:Mice; D007703:Peptidyl-Dipeptidase A / Q000032:analysis / Q000302:isolation & purification*; D043782:Receptor, Bradykinin B2 / Q000032:analysis*
D043782:Receptor, Bradykinin B2; D002216:Captopril; D007703:Peptidyl-Dipeptidase A; D015773:Enalaprilat