Bradykinin B2 receptors play a neuroprotective role in Hypoxia/reoxygenation injury related to pyroptosis pathway

Title:Bradykinin B2 receptors play a neuroprotective role in Hypoxia/reoxygenation injury related to pyroptosis pathway

Volume: 15 Issue: 2

Author(s): Min Tang*, Xia Li, Ping Liu, Jianwen Wang, Fangping He and Xiongchao Zhu

Affiliation:

• Department of Neurology, The First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, Zhejiang Province, 310003,China

Keywords: Bradykinin B2 receptor, hypoxia/reoxygenation, GSDMD, pyroptosis, ischemic stroke, inflammatory responses.

Abstract: Background: Kinins are pro-inflammatory peptides that mediate numerous vascular and pain responses in tissue injury. Kinins exert their biological functions via two G-protein-coupled receptors: Bradykinin 1 Receptor (B1R) and Bradykinin 2 Receptor (B2R). We previously demonstrated the up-regulation of B2R after Hypoxia/Reoxygenation (H/R) injury in primary cultured cortical neurons. However, the role of B2R in inflammasome-induced pyroptosis remains unknown.

Methods: We induced H/R neuronal injury in primary cultured cortical neurons harvested from embryonic day 17 brains. Next, we examined the neuroprotective function of B2R in H/R-induced neuronal apoptosis or necrosis using an annexin V FITC/Propidium Iodide (PI) double-staining technique. The pyroptosis signaling cascade, including caspase-1, IL-1β and IL-18 levels and Cleaved Gasdermin D (GSDMD) expression was examined by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting to explore the underlying molecular mechanism.

Results: H/R injury significantly increased B2R protein expression (P<0.05) as well as the percentage of early apoptotic and necrotic or late apoptotic neurons as verified by the annexin V FITC/PI flow cytometric analysis. Bradykinin (BK), a specific B2R agonist, caused a significant decrease in apoptotic neuronal death after H/R injury, while HOE140, a specific B2R antagonist, markedly reduced the neuroprotective effect of B2R. Following H/R injury, BK downregulated the caspase-1, IL-1β and IL-18 levels (P<0.01). In contrast, pretreatment with HOE140 significantly increased caspase-1, IL-1β, and IL-18 levels (P<0.01). Further analysis revealed that GSDMD, a key executioner of pyroptosis, is a target for B2R-mediated inhibition of neuronal pyroptosis. Cleaved GSDMD expression was significantly inhibited by BK pretreatment and significantly enhanced by HOE140 pretreatment (P<0.01).

Conclusion: These results indicate that activation of B2R plays an important role in pyroptosis mediated by H/R injury.

Cite this article as:

Tang Min *, Li Xia , Liu Ping , Wang Jianwen , He Fangping and Zhu Xiongchao, Bradykinin B2 receptors play a neuroprotective role in Hypoxia/reoxygenation injury related to pyroptosis pathway, Current Neurovascular Research 2018; 15 (2) . https://dx.doi.org/10.2174/1567202615666180528073141