OS059. Blockade of the bradykinin B2 receptor in early pregnancy reduces fetal growth and trophoblast invasion in guinea-pigs

MiR-29b-3p affects growth and biological functions of human extravillous trophoblast cells by regulating bradykinin B2 receptor

INTRODUCTION

This study investigated miR-29b-3p's effects and mechanisms in preeclampsia development.

MATERIAL AND METHODS

In this study, we analysed the pathology and expression of miR-29b-3p and B2R mRNA from normal and preeclampsia placenta tissues using hematoxylin and eosin staining and RT-qPCR assay. For cell experiments, we used transwell assay CCK-8, flow cytometry and wound healing assay to determine the effects and correlation of miR-29b-3p and B2R in HTR-8/SVneo cell proliferation, apoptosis, cell cycle, cell invasion and migration in a preeclampsia cell model. Moreover, the mechanisms were determined using Western blot or immunofluorescence in different groups.

RESULTS

Clinical analysis revealed that miR-29b-3p gene expression dramatically increased with increasing degree of preeclampsia (p < 0.001 or p < 0.05, respectively). The HTR-8/SVneo cell biological activities of the model group were significantly depressed (p < 0.001). However, with miR-29b-3p inhibitor or B2R transfection, the HTR-8/SVneo cell biological activities significantly recovered (p < 0.001). Western blot assay showed that B2R, VEGF-A, CCND-1, MMP-2 and MMP-9 levels were suppressed in the model group, compared with those in the NC groups (p < 0.001, respectively). With miR-29b-3p inhibitor or B2R transfection, the protein expression levels of B2R, VEGF-A, CCND-1, MMP-2 and MMP-9 dramatically increased (p < 0.001, respectively).

CONCLUSIONS

The down-regulation of miR-29b-3p could improve HTR-8/SVneo cell biological activities in a preeclampsia cell model by targeting B2R.

Myocardial angiogenesis induced by exercise training involves a regulatory mechanism mediated by kinin receptors

OBJECTIVE

To demonstrate that the kallikrein-kinin system (KKS) is upstream of angiogenic signaling pathway, and to determine the role of the kinin B1 and B2 receptors in myocardial angiogenesis induced by exercise training.

METHODS

Forty Wistar rats were randomly assigned to an exercise control (EC) group, a B1 receptor antagonist (B1Ant) group, a B2 receptor antagonist (B2Ant) group, and a double receptor antagonist ((B1+ B2)Ant) group. A myocardial infarction model was employed. Animals in all groups received 30 min of exercise training for 4 weeks. The expression of VEGF and eNOS, capillary supply, and apoptosis rate were evaluated.

RESULTS

The mRNA and protein expression of VEGF and eNOS showed similar trends in all groups, and were lowest in the (B1+ B2) Ant group, and highest in the EC group. Levels of VEGF and eNOS mRNA were significantly lower in the B1Ant group than in the B2Ant group (p< .001 and p< .05, respectively). VEGF and eNOS protein in the B1Ant group was also significantly lower (p< .01 and p< .05, respectively) than in the B2Ant group. The capillary numbers in the (B1+ B2) Ant group were significantly lower than in the EC group (395.8 ± 105 vs. 1127.9 ± 192.98, respectively). The apoptosis rate of cardiomyocytes was highest in the (B1+ B2) Ant group.

CONCLUSION

KKS may act as an upstream signal transduction pathway for angiogenic factors in myocardial angiogenesis. The B1 and B2 receptors exert additive effects, and the B1 receptor has the most prominent role in mediating KKS-induced myocardial angiogenesis.

Bradykinin receptor blockade restores the baroreflex control of renal sympathetic nerve activity in cisplatin-induced renal failure rats

AIM

This study investigated the effect of renal bradykinin B1 and B2 receptor blockade on the high- and low-pressure baroreceptor reflex regulation of renal sympathetic nerve activity (RSNA) in rats with cisplatin-induced renal failure.

METHODS

Cisplatin (5 mg/kg) or saline was given intraperitoneally 4 days prior to study. Following chloralose/urethane anaesthesia, rats were prepared for measurement of mean arterial pressure (MAP), heart rate and RSNA and received intrarenal infusions of either Lys-[des-Arg⁹ , Leu⁸ ]-bradykinin (LBK), a bradykinin B1 receptor blocker, or bradyzide (BZ), a bradykinin B2 receptor blocker. RSNA baroreflex gain curves and renal sympatho-inhibitory responses to volume expansion (VE) were obtained.

RESULTS

In the control and renal failure groups, basal MAP (89 ± 3 vs. 80 ± 8 mmHg) and RSNA (2.0 ± 0.3 vs. 1.7 ± 0.6 μV.s) were similar but HR was lower in the latter group (331 ± 8 vs. 396 ± 9 beats/min). The baroreflex gain for RSNA in the renal failure rats was 39% (P < 0.05) lower than the control but was restored to normal values following intrarenal infusion of BZ, but not LBK. VE had no effect on MAP or HR but reduced RSNA by some 40% (P < 0.05) in control but not renal failure rats. Intrarenal LBK infusion in the renal failure rats normalized the VE induced renal sympatho-inhibition whereas BZ only partially restored the response.

CONCLUSION

These findings suggest that pro-inflammatory bradykinin acting at different receptors within the kidney generates afferent neural signals which impact differentially within the central nervous system on high- and low-pressure regulation of RSNA.