Reversal of pulmonary arterial hypertension and neointimal formation by kinin B1 receptor blockade

Background This study examined whether BI113823, a novel selective kinin B1 receptor antagonist can reverse established pulmonary arterial hypertension (PAH), prevent right heart failure and death, which is critical for clinical translation. Methods Left pneumonectomized male Wistar rats were injected with monocrotaline to induce PAH. Three weeks later, when PAH was well established, the rats received daily treatment of BI113823 or vehicle for 3 weeks. Results Treatment with BI113823 from day 21 to day 42 after monocrotaline injection reversed established PAH as shown by normalized values of mean pulmonary arterial pressure (mPAP). BI113823 therapy reversed pulmonary vascular remodeling, pulmonary arterial neointimal formation, and heart and lung fibrosis, reduced right ventricular pressure, right heart hypertrophy, improved cardiac output, and prevented right heart failure and death. Treatment with BI113823 reduced TNF-α and IL-1β, and macrophages recruitment in bronchoalveolar lavage, reduced CD-68 positive macrophages and expression of proliferating cell nuclear antigen (PCNA) in the perivascular areas, and reduced expression of iNOS, B1 receptors, matrix metalloproteinase (MMP)-2 and MMP-9 proteins, and the phosphorylation of ERK1/2 and AKT in lung. Treatment with BI113823 reduced mRNA expression of ANP, BNP, βMHC, CGTF, collange-I and IV in right heart, compared to vehicle treated controls. In human monocytes cultures, BI113823 reduced LPS-induced TNF-α production, MMP-2 and MMP-9 expression, and reduced TNF-α-induced monocyte migration. Conclusions We conclude that BI113823 reverses preexisting severe experimental pulmonary hypertension via inhibition of macrophage infiltration, cytokine production, as well as down regulation of matrix metalloproteinase proteins.

Hypothalamic kinin B1 receptor mediates orexin system hyperactivity in neurogenic hypertension

Brain orexin system hyperactivity contributes to neurogenic hypertension. We previously reported upregulated neuronal kinin B1 receptor (B1R) expression in hypertension. However, the role of central B1R activation on the orexin system in neurogenic hypertension has not been examined. We hypothesized that kinin B1R contributes to hypertension via upregulation of brain orexin-arginine vasopressin signaling. We utilized deoxycorticosterone acetate (DOCA)-salt hypertension model in wild-type (WT) and B1R knockout (B1RKO) mice. In WT mice, DOCA-salt-treatment increased gene and protein expression of orexin A, orexin receptor 1, and orexin receptor 2 in the hypothalamic paraventricular nucleus and these effects were attenuated in B1RKO mice. Furthermore, DOCA-salt- treatment increased plasma arginine vasopressin levels in WT mice, but not in B1RKO mice. Cultured primary hypothalamic neurons expressed orexin A and orexin receptor 1. B1R specific agonist (LDABK) stimulation of primary neurons increased B1R protein expression, which was abrogated by B1R selective antagonist R715 but not by the dual orexin receptor antagonist, ACT 462206, suggesting that B1R is upstream of the orexin system. These data provide novel evidence that B1R blockade blunts orexin hyperactivity and constitutes a potential therapeutic target for the treatment of salt-sensitive hypertension.

MO067DELETION AND BLOCKAGE OF KININ B1 RECEPTOR EXACERBATES CISPLATIN-INDUCED CKD

Background and Aims Kinins plays a major role in immune response, where kinin B2 receptor is constitutively expressed and kinin B1 receptor is induced under inflammatory stimuli. Kinin B1 receptor deletion and blockage has been shown to have beneficial effects in some models of renal diseases. Multiple acute renal insults, even if followed by renal recovery, is a risk factor for the future development of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Our main objective was to determine the importance of kinin B1 receptor in tubulointerstitial fibrosis induced by ongoing cisplatin treatment. Method Male C57/Bl6 mice were divided in 3 groups, vehicle, cisplatin, cisplatin + R715 (kinin B1 receptor antagonist). Animals has been treated with multiple doses of cisplatin (7mg/kg i.p) once a week during 4 weeks and R715 (0.8mg/kg i.p) 48, 24 and 1 hour prior to cisplatin injections. We also used B1KO mice (C57Bl6 background) and WT mice (littermates). Mice were euthanized after 30 days of last cisplatin injection. Renal parameters, histology, real time PCR were performed to investigate renal injury, inflammation and fibrosis. Results Cisplatin treatment increases most of renal parameters, renal injury and fibrosis markers. Deletion of B1 receptor exacerbates significantly creatinine (WT CIS 0,60+0,03 B1KO 0,76+0,01 mg/dL), urea (WT CIS 111,8+5,638 B1KO CIS 240,8+28,60 mg/dL), and protein excretion (WT CIS 0,0058+0,0011 B1KO CIS 0,0121+0,0007 mg/24h). Association of cisplatin with R715 increased creatinine levels (veh 0,43+0,03 cis+R715 0,64+0,04 mg/dL), exacerbates urea (cis 95,51 + 3,926 cis+R715 158,9+14,40 mg/dL) and protein excretion (cis 0,012+0,002 cis+R715 0,018+0,003 mg/24h). Renal injury markers such as KIM-1 and TNF-a showed no significant differences. NGAL expression exacerbates (cis 2,53+0,44 cis+R715 5,66+1,34) and tubular injury score (cis 0,130+0,021 cis+R715 0,191+0,020) is higher in cisplatin+R715 group. Fibrosis markers a-SMA (cis 2,56+0,43 cis+R715 4,67+0,99), Col4 (cis 2,57+0,39 cis+R715 5,14+1,01) and Vimentin (2,69+0,31 cis+R715 4,62+0,98) were exacerbated in cisplatin treatment associated with R715. Picrosirius red staining were used to asses tubulointerstitial fibrosis, and we confirmed that R715 treatment here also exacerbates fibrosis (cis 0,225+0,025 cis+R715 0,345+0,042). Conclusion Here we show that both deletion and blockage of kinin B1 receptor has deleterious effects in renal injury and fibrosis induced by ongoing cisplatin treatment.

Activation of Kinin B1R Upregulates ADAM17 and Results in ACE2 Shedding in Neurons

Angiotensin converting enzyme 2 (ACE2) is a critical component of the compensatory axis of the renin angiotensin system. Alterations in ACE2 gene and protein expression, and activity mediated by A Disintegrin And Metalloprotease 17 (ADAM17), a member of the “A Disintegrin And Metalloprotease” (ADAM) family are implicated in several cardiovascular and neurodegenerative diseases. We previously reported that activation of kinin B1 receptor (B1R) in the brain increases neuroinflammation, oxidative stress and sympathoexcitation, leading to the development of neurogenic hypertension. We also showed evidence for ADAM17-mediated ACE2 shedding in neurons. However, whether kinin B1 receptor (B1R) activation has any role in altering ADAM17 activity and its effect on ACE2 shedding in neurons is not known. In this study, we tested the hypothesis that activation of B1R upregulates ADAM17 and results in ACE2 shedding in neurons. To test this hypothesis, we stimulated wild-type and B1R gene-deleted mouse neonatal primary hypothalamic neuronal cultures with a B1R-specific agonist and measured the activities of ADAM17 and ACE2 in neurons. B1R stimulation significantly increased ADAM17 activity and decreased ACE2 activity in wild-type neurons, while pretreatment with a B1R-specific antagonist, R715, reversed these changes. Stimulation with specific B1R agonist Lys-Des-Arg9-Bradykinin (LDABK) did not show any effect on ADAM17 or ACE2 activities in neurons with B1R gene deletion. These data suggest that B1R activation results in ADAM17-mediated ACE2 shedding in primary hypothalamic neurons. In addition, stimulation with high concentration of glutamate significantly increased B1R gene and protein expression, along with increased ADAM17 and decreased ACE2 activities in wild-type neurons. Pretreatment with B1R-specific antagonist R715 reversed these glutamate-induced effects suggesting that indeed B1R is involved in glutamate-mediated upregulation of ADAM17 activity and ACE2 shedding.

Kinin B1 receptor is involved in mechanical nociception in a fibromyalgia-like model in mice

Fibromyalgia-like models in mice induced by reserpine have opened a new avenue to understanding the molecular mechanisms behind this complex and incapacitating pain syndrome. The kinin B1 receptor (B1R) contributes to mechanical allodynia and acute coping behavior in mice with inflammatory and immunological disorders. This study has replicated previous data where amine depletion induced by reserpine significantly decreased the dopamine and serotonin levels in the prefrontal cortex (PFC), hippocampus (HPC), and spinal cord of mice. The animals subjected to the reserpine fibromyalgia model also showed decreased paw withdrawal threshold (PWT) and increased the immobility time in the forced swimming test (FST). Genetic ablation of B1R or pharmacological blockade by selective kinin B1R antagonist R-715 (acute i.p. treatment) counteracted the mechanical allodynia and increased immobility time induced by reserpine. However, neither pharmacological nor genetic inhibition of B1R reversed monoamine depletion. Our data confirm that reserpine induced a fibromyalgia-like phenotype in mice and reiterated the role of B1R on acute coping behavior and nociception modulation.

Blockade of Kinin B1 receptor counteracts the depressive-like behavior and mechanical allodynia in ovariectomized mice

Menopause is related to a decline in ovarian estrogen production, affecting the perception of the somatosensory stimulus, changing the immune-inflammatory systems, and triggering depressive symptoms. Inhibition of kinin B1 and B2 receptors (B1R and B2R) inhibits the depressive-like behavior and mechanical allodynia induced by immune-inflammatory mediators in mice. However, there is no evidence on the role of kinin receptors in depressive-like and nociceptive behavior in female mice submitted to bilateral ovariectomy. This study shows that ovariectomized mice (OVX) developed time-related mechanical allodynia and increased immobility time in the tail suspension test (TST). The genetic deletion of B1R, or the pharmacological blockade by selective kinin B1R antagonist R-715 (acute, i.p), reduced the increase of immobility time and mechanical allodynia induced by ovariectomy. Neither genetic deletion nor pharmacological inhibition of B2R (HOE 140, i.p) prevented the behavioral changes elicited by OVX. Our data suggested a particular modulation of kinin B1R in the nociceptive and depressive-like behavior in ovariectomized mice. Selective inhibition of the B1R receptor may be a new pharmacological target for treating pain and depression symptoms in women on the perimenopause/menopause period.