Glucagon Reduces Neutrophil Migration and Increases Susceptibility to Sepsis in Diabetic Mice

Abstract

Sepsis is one of the most common comorbidities observed in diabetic patients, associated with a deficient innate immune response. Recently, we have shown that glucagon possesses anti-inflammatory properties. In this study, we investigated if hyperglucagonemia triggered by diabetes might reduce the migration of neutrophils, increasing sepsis susceptibility. 21 days after diabetes induction by intravenous injection of alloxan, we induced moderate sepsis in Swiss-Webster mice through cecum ligation and puncture (CLP). The glucagon receptor (GcgR) antagonist des-his1-[Glu9]-glucagon amide was injected intraperitoneally 24h and 1h before CLP. We also tested the effect of glucagon on CXCL1/KC-induced neutrophil migration to the peritoneal cavity in mice. Neutrophil chemotaxis in vitro was tested using transwell plates, and the expression of total PKA and phospho-PKA was evaluated by western blot. GcgR antagonist restored neutrophil migration, reduced CFU numbers in the peritoneal cavity and improved survival rate of diabetic mice after CLP procedure, however, the treatment did no alter hyperglycemia, CXCL1/KC plasma levels and blood neutrophilia. In addition, glucagon inhibited CXCL1/KC-induced neutrophil migration to the peritoneal cavity of non-diabetic mice. Glucagon also decreased the chemotaxis of neutrophils triggered by CXCL1/KC, PAF, or fMLP in vitro. The inhibitory action of glucagon occurred in parallel with the reduction of CXCL1/KC-induced actin polymerization in neutrophils in vitro, but not CD11a and CD11b translocation to cell surface. The suppressor effect of glucagon on CXCL1/KC-induced neutrophil chemotaxis in vitro was reversed by pre-treatment with GcgR antagonist and adenylyl cyclase or PKA inhibitors. Glucagon also increased PKA phosphorylation directly in neutrophils in vitro. Furthermore, glucagon impaired zymosan-A-induced ROS production by neutrophils in vitro. Human neutrophil chemotaxis and adherence to endothelial cells in vitro were inhibited by glucagon treatment. According to our results, this inhibition was independent of CD11a and CD11b translocation to neutrophil surface or neutrophil release of CXCL8/IL-8. Altogether, our results suggest that glucagon may be involved in the reduction of neutrophil migration and increased susceptibility to sepsis in diabetic mice. This work collaborates with better understanding of the increased susceptibility and worsening of sepsis in diabetics, which can contribute to the development of new effective therapeutic strategies for diabetic septic patients.

Association of Admission Blood Glucose Level with All-Cause Mortality According to Age in Patients with Community Acquired Pneumonia

“…It is argued that a hyperglycemic environment may impair the function of neutrophils and monocytes and increase susceptibility to certain organisms. 8,9 A Danish retrospective study involving 1318 adult CAP patients reported that in subjects without diabetes metabolism, a higher blood glucose level was an independent predictor for intensive care unit (ICU) admission (OR=1.25, 95% CI 1.13-1.39). 10 Multivariate logistic regression analysis in a Chinese retrospective study showed that a higher admission blood glucose level was significantly associated with the 30-day all-cause mortality (OR=1.91, 95% CI:…”

Effect of the renin-angiotensin system on the exacerbation of adrenal glucocorticoid steroidogenesis in diabetic mice: Role of angiotensin-II type 2 receptor

“…Male Swiss-Webster mice (5-6 weeks old with 20 to 25g) were obtained from Oswaldo Cruz Foundation breeding colony and used in accordance with the guidelines of the Committee on Use of Laboratory Animals of Oswaldo Cruz Institute (CEUA-IOC/Fiocruz, license L-027/2016). Diabetes was randomly and blinded designated induced in 12 hours fasted mice (water ad libitum ) by a single intravenous injection of alloxan monohydrate (65 mg/kg) ( 20 ) diluted with sterile saline (0.9% NaCl). Only mice showing two successive determinations of blood glucose levels (3 and 7 days after alloxan injection) greater than 16.7 mmol/L were considered diabetic and included in the experiment.…”

“…All solutions were prepared immediately before use. blinded designated induced in 12 hours fasted mice (water ad libitum) by a single intravenous injection of alloxan monohydrate (65 mg/kg) (20) diluted with sterile saline (0.9% NaCl). Only mice showing two successive determinations of blood glucose levels (3 and 7 days after alloxan injection) greater than 16.7 mmol/L were considered diabetic and included in the experiment.…”

Crosstalk between gut microbiota and renal ischemia/reperfusion injury

“…Under normal physiological conditions, the intestine has a regulatory effect on kidney function, including neuroendocrine involvement. For example, glucagon-like peptide-1 (GLP-1) ( Wu et al., 2021a ; Zhuang et al., 2021 ), guanosine ( Estaki et al., 2014 ), glucagon ( Müller et al., 2020 ; Insuela et al., 2021 ), vasoactive intestinal peptide ( Song et al., 2021 ), polypeptide ( Qi et al., 2021 ), gastrin ( Stewart et al., 2020 ) and other intestinal factors can regulate renal dysfunction. Pathological conditions, due to dietary restrictions and gastrointestinal, most of the patients in the gut microbial metabolism, which is mainly composed of protein hydrolysis into fermentation mode, the end product of protein by the metabolism of gut microbes such as phenol, indole are the endotoxin source of uremia, such as its nephrotoxicity and vascular toxicity has been confirmed that many clinical research institute ( Ondrussek-Sekac et al., 2021 ).…”