Pro‐BDNF Contributes to Hypoxia/Reoxygenation Injury in Myocardial Microvascular Endothelial Cells: Roles of Receptors p75^NTR and Sortilin and Activation of JNK and Caspase 3

Abstract

The aim of this study was to identify the role of the precursor of the brain-derived neurotrophic factor (pro-BDNF) in myocardial hypoxia/reoxygenation injury (H/R) and to address the underlying mechanisms. For this purpose, myocardial microvascular endothelial cells (MMECs) exposed to a high concentration of glucose (30 mM) for 48 h were subjected to 4 h of hypoxia followed by 2 h of reoxygenation. Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) staining and flow-cytometric analysis were performed to detect apoptosis. Cell scratch and capillary-like-structure formation assays were employed to evaluate cell function. The levels of apoptosis-related proteins were evaluated by Western blotting and immunofluorescence assays. Our results showed that H/R resulted in MMEC injury, as indicated by significant increases in TUNEL-positive cell numbers and a reduction in MMEC migration and in capillary-like-structure formation coupled with increased pro-BDNF protein expression. In addition, overexpression of pro-BDNF in MMECs via a viral vector led to increased pro-BDNF expression, and this upregulation induced apoptosis. Mechanistic experiments revealed that H/R did not influence BDNF, JNK, and caspase 3 expression, but upregulated pro-BDNF, p75NTR, sortilin, phospho-JNK, and cleaved caspase 3 protein levels. In contrast, neutralization of endogenous pro-BDNF with an antibody significantly attenuated H/R-induced upregulation of pro-BDNF, p75NTR, sortilin, p-JNK, and cleaved caspase 3 protein levels, indicating that p75NTR-sortilin signaling and activation of JNK and caspase 3 may be involved in these effects. In conclusion, H/R-induced injury may be mediated by pro-BDNF, at least in part through the regulation of p75NTR-sortilin signaling and activation of JNK and caspase 3.

Exosomal circHIPK3 Released from Hypoxia-Pretreated Cardiomyocytes Regulates Oxidative Damage in Cardiac Microvascular Endothelial Cells via the miR-29a/IGF-1 Pathway

“…The apoptosis of CMVECs was determined by FCM using Annexin V-FITC/propidium iodide (PI) staining assay kits (Solarbio, China) according to the manufacturer's instructions, as previously reported [1]. CMVEC apoptosis was analyzed via a FACSCalibur flow cytometer (BD Biosciences, USA).…”

“…Microcirculatory dysfunction is an important etiological component of ischemia-reperfusion injury [1]. Oxidative stress caused by a surge in the generation of reactive oxygen species (ROS) during reoxygenation can disrupt microvascular integrity [2], consequently decreasing the oxygen and nutrients supplied to cardiac cells.…”

Tetrahydroxystilbene Glucoside Ameliorates Infrasound-Induced Central Nervous System (CNS) Injury by Improving Antioxidant and Anti-Inflammatory Capacity

“…Apoptosis-Related Genes. Bcl-2 [38], BAX [39], and caspase-3 [40,41] have been reported to be associated with oxidative stress and apoptosis. Infrasound treatment reduced relative mRNA level of Bcl-2 and a sharp increase in relative mRNA levels of bax and caspase-3.…”

CircHIPK3 Plays Vital Roles in Cardiovascular Disease

“…Several factors could contribute to I/R injury, including microcirculatory dysfunction and oxidative stress ( 50 , 80 ). Cardiac microvascular endothelial cells (CMVECs) play a critical role in microcirculation and regulate cardiac function ( 81 , 82 ).…”