BDKRB1 activation induces CXCR2 desensitization in neutrophils during severe sepsis and exacerbates disease severity
Raquel Duque do Nascimento Arifa, Carolina Braga Resende Mascarenhas, Lívia Caroline Resende Rossi, Maria Eduarda Freitas Silva, Larissa M. Lucas, João Paulo Pezzini Barbosa, Daiane Boff, Brenda Gonçalves Resende, Lívia Duarte Tavares, Alesandra Corte Reis, Vanessa Pinho, Flavio Almeida Amaral, Caio Tavares Fagundes, Cristiano Xavier Lima, Mauro Martins Teixeira, Daniele G Souza
Raquel Duque do Nascimento Arifa, Carolina Braga Resende Mascarenhas, Lívia Caroline Resende Rossi, Maria Eduarda Freitas Silva, Larissa M. Lucas, João Paulo Pezzini Barbosa, Daiane Boff, Brenda Gonçalves Resende, Lívia Duarte Tavares, Alesandra Corte Reis, Vanessa Pinho, Flavio Almeida Amaral, Caio Tavares Fagundes, Cristiano Xavier Lima, Mauro Martins Teixeira, Daniele G Souza
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Research Article Inflammation Microbiology

BDKRB1 activation induces CXCR2 desensitization in neutrophils during severe sepsis and exacerbates disease severity

Abstract

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. During early sepsis, kinins are released and bind to B1 (BDKRB1) and B2 (BDKRB2) bradykinin receptors, but the involvement of these receptors in sepsis remains incompletely understood. This study demonstrated that the genetic deletion of Bdkrb2 had no significant impact on sepsis induced by cecal ligation and puncture (CLP) compared to wild-type (WT) mice. In contrast, Bdkrb1−/− mice subjected to CLP exhibited decreased lethality and bacterial load, associated with an increased influx of neutrophils into the peritoneal cavity, compared with WT mice. Neutrophils from CLP-Bdkrb1−/− mice partially restored CXCR2 expression and reduced the upregulation of P110γ observed in WT CLP neutrophils. Pharmacologic inhibition of BDKRB1 combined with imipenem treatment substantially improved survival compared with antibiotic therapy alone. In human neutrophils, stimulation with LPS led to the upregulation of BDKRB1 expression, and antagonism of BDKRB1 restored neutrophil migration in response to CXCL8. These findings identify BDKRB1 as an important modulator of neutrophil dysfunction in sepsis and a promising therapeutic target whose inhibition improves bacterial clearance, restores neutrophil migration, and increases the efficacy of antibiotic treatment.

Authors

Raquel Duque do Nascimento Arifa, Carolina Braga Resende Mascarenhas, Lívia Caroline Resende Rossi, Maria Eduarda Freitas Silva, Larissa M. Lucas, João Paulo Pezzini Barbosa, Daiane Boff, Brenda Gonçalves Resende, Lívia Duarte Tavares, Alesandra Corte Reis, Vanessa Pinho, Flavio Almeida Amaral, Caio Tavares Fagundes, Cristiano Xavier Lima, Mauro Martins Teixeira, Daniele G Souza

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Figure 6

Treatment with a BDKRB1 antagonist prevents neutrophil dysfunction, bacterial burden, inflammation, and lethality associated with CLP in WT mice.

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Treatment with a BDKRB1 antagonist prevents neutrophil dysfunction, bact...
(A) Survival of WT mice treated with a BDKRB1 antagonist alone and (B) survival of mice treated post-CLP with both a BDKRB1 antagonist and the antibiotic imipenem, monitored for 14 days. Imipenem was administered 3 hours after sepsis induction. Survival rates (%) were analyzed using the log-rank (Mantel-Cox) test; n = 10 mice per group. WT mice received the BDKRB1 antagonist DALBK (50 nM/kg) either 1 hour before (pretreatment) or 3 hours after (posttreatment) CLP. Six hours after CLP, mice were euthanized, and blood, lungs, and peritoneal lavage fluid were collected. (C) Total leukocyte count, (D) neutrophil influx into the peritoneal cavity, and (E) bacterial load (CFU) were evaluated. Concentrations of TNF were measured in the (F) peritoneal lavage, (G) lung, and (H) serum. CXCL1 levels were measured in the (I) peritoneal lavage, (J) lung, and (K) serum. (L) MPO activity was assessed in lung tissue. Survival analysis was performed with at least 10 animals per group. The Mantel-Cox log-rank test (χ2) was used for statistical analysis of survival curves. ANOVA followed by Tukey’s multiple comparisons posttest was used for data with a normal distribution. For data that did not follow a normal distribution, the Kruskal-Wallis test followed by Dunn’s multiple comparisons posttest was applied to compare 3 or more independent groups. Results are expressed as mean ± SEM from at least 5 animals per group. *P < 0.05 vs. sham group; #P < 0.05 vs. WT-CLP group. All experiments were replicated at least twice; 1 representative experiment is shown.