Heteromerization Between the Bradykinin B2 Receptor and the Angiotensin-(1-7) Mas Receptor: Functional Consequences

BRUNO D. CERRATO, OSCAR A. CARRETERO, BRANA JANIC, HERNÁN E. GRECCO, MARIELA M. GIRONACCI

HYPERTENSION

LIPPINCOTT WILLIAMS & WILKINS

Lugar: Philadelphia; Año: 2016

0194-911X

Bradykinin (BK) B2 receptor (R) and angiotensin (Ang) (1-7) MasR mediated effects are physiologically interconnected. The molecular basis for such cross-talk is unknown. It is hypothesized that the cross-talk occurs at the R level. We investigated B2R-MasR heteromerization and the functional consequences of such interaction. B2R fused to the cyan fluorescent protein and MasR fused to the yellow fluorescent protein were transiently co-expressed in HEK293T cells. Fluorescence resonance energy transfer (FRET) analysis showed that B2R and MasR formed a constitutive heteromer, which was not modified by their agonists. B2R or MasR antagonists decreased FRET efficiency, suggesting that the antagonist promoted heteromer dissociation. B2R-MasR heteromerization induced an 8-fold increase in the MasR ligand binding affinity. Upon agonist stimulation, the heteromer was internalized into early endosomes with a slower sequestration rate from the plasma membrane, compared to the single Rs. B2R-MasR heteromerization induced a greater increase in arachidonic acid release and ERK phosphorylation after Ang-(1-7) stimulation, and this effect was blocked by the B2R antagonist. Concerning Akt activity, a significant BK promoted activation was detected in B2R-MasR- but not in B2R-expressing cells. Ang-(1-7) and BK elicited anti-proliferative effects only in cells expressing B2R-MasR heteromers, but not in cells expressing each R alone. Proximity ligarion assay confirmed B2R-MasR interaction in human glomerular endothelial cells supporting the interaction between both Rs in vivo. Our findings provide an explanation for the cross-talk between BK B2R and Ang-(1-7) MasR mediated effects. B2R-MasR heteromerization induces functional changes in the R that may lead to long-lasting protective properties.