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Interactions of Angiotensin Converting Enzyme 2 with Fascin‐1 as a Novel Mechanism in Regulation of its Enzymatic Activity
Author(s) -
Ogunlade Blessing,
Guidry Jesse J,
Lazartigues Eric,
Filipeanu Catalin
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.lb324
Subject(s) - internalization , angiotensin ii , renin–angiotensin system , angiotensin converting enzyme 2 , fascin , hek 293 cells , chemistry , microbiology and biotechnology , downregulation and upregulation , receptor , transfection , enzyme , cytoplasm , medicine , endocrinology , biology , biochemistry , actin , gene , disease , covid-19 , blood pressure , infectious disease (medical specialty)
Angiotensin converting enzyme 2 (ACE2) catalyzes the conversion of Angiotensin (Ang)‐II to Ang‐(1–7), attenuating the deleterious effects of angiotensin type 1 receptor (AT1R) activation on the cardiovascular functions. Our group originally demonstrated that increased Ang‐II levels stimulate interactions between ACE2 and AT1R followed by enzyme degradation into lysosomes, overall leading to a diminished compensatory activity against overactive renin‐angiotensin system. Although we showed that lysosomal inhibitors largely prevent Ang‐II mediated hypertension in vivo , the cellular mechanisms regulating ACE2 degradation by elevated Ang‐II remain largely unknown. To start elucidating these aspects, we performed a proteomic experiment in Neuro2A cells to find binding partners of ACE2 which interactions are modulated by Ang‐II. Surprisingly, only fascin‐1, an actin‐bundling protein displayed differential interactions with ACE2 in these conditions, suggesting that it may be involved in ACE2 internalization and degradation. The interactions between ACE2 and fascin‐1 were confirmed by confocal microscopy. These experiments also demonstrated that in control conditions ACE2/fascin‐1 complexes are localized at the plasma membrane. Treatment with Ang‐II (100 nM, 4 h) induced internalization of these complexes within cytoplasm. Preliminary experiments determining the total cellular levels of ACE2 in transfected HEK293T by western‐blot demonstrated that Ang‐II treatment for 18 h significantly decrease the cellular enzyme levels. In contrast, in cells overexpressing fascin‐1, ACE2 cellular levels were preserved despite treatment with Ang‐II. Similarly, in HEK293T cells co‐transfected with ACE2 and AT1R, treatment with Ang‐II (100 nM, 4 h) diminished the basal enzymatic activity (18382 ±2430) by 36 ±12%. Overexpression of fascin‐1 did not significantly change ACE2 basal activity ( 86 ±24% ), but in these cells Ang‐II was unable to decrease enzymatic activity ( 85 ± 28% ). In conclusion, our results reveal for the first time a potential role of fascin‐1 in cardiovascular diseases. As an ACE2 binding partner, fascin‐1 may prevent enzyme degradation in presence of elevated Ang‐II and it appears that its cellular levels are critical in prevention of the deleterious effects of overactive renin‐angiotensin system. Also, these data highlight fascin‐1 as an additional possible therapeutic target in the treatment of cardiovascular diseases. Support or Funding Information 5 P30 GM106392‐03 (JJG). NHLBI HL093178 (EL) and a Bridge Grant from Howard University (CMF). This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .