Inhibition of endothelin A receptor protects brain microvascular endothelial cells against hypoxia-induced injury

Roles of Astrocytic Endothelin ETB Receptor in Traumatic Brain Injury

Traumatic brain injury (TBI) is an intracranial injury caused by accidents, falls, or sports. The production of endothelins (ETs) is increased in the injured brain. ET receptors are classified into distinct types, including ET_A receptor (ET_A-R) and ET_B receptor (ET_B-R). ET_B-R is highly expressed in reactive astrocytes and upregulated by TBI. Activation of astrocytic ET_B-R promotes conversion to reactive astrocytes and the production of astrocyte-derived bioactive factors, including vascular permeability regulators and cytokines, which cause blood-brain barrier (BBB) disruption, brain edema, and neuroinflammation in the acute phase of TBI. ET_B-R antagonists alleviate BBB disruption and brain edema in animal models of TBI. The activation of astrocytic ET_B receptors also enhances the production of various neurotrophic factors. These astrocyte-derived neurotrophic factors promote the repair of the damaged nervous system in the recovery phase of patients with TBI. Thus, astrocytic ET_B-R is expected to be a promising drug target for TBI in both the acute and recovery phases. This article reviews recent observations on the role of astrocytic ET_B receptors in TBI.

Effects of SRC and IKKβ Kinase Inhibition in Ischemic Factors Modeling In Vitro and In Vivo

The search for new molecular targets whose modulation can reduce nerve cell dysfunction and neuronal death during ischemic damage is one of the most significant issues in both fundamental and clinical neurobiology. Various kinase enzymes are often considered to be such promising targets since they are involved in key molecular cascades that regulate cell adaptation to stress factors. Our work is devoted to the study of the role of two kinases—SRC and IKKβ—in maintaining the neural networks’ functional activity under a hypoxic condition in vivo and in vitro. SRC kinase is a cytoplasmic non-receptor protein tyrosine kinase. It is involved in the regulation of cell proliferation and differentiation; its expression in nerve cells changes during hypoxia. IKKβ kinase is involved in the regulation of the activity of the transcription factor NF-κB, which is a pleiotropic regulator of many cellular signaling pathways. We have shown that blockade of SRC and IKKβ kinases by selective inhibitors maintains cell viability in modeling hypoxic damage in vitro but does not allow for the preservation of the bioelectrical activity of neurons. Studies in vivo have shown the neuroprotective effect of SRC but not IKKβ kinase inhibition in the modeling of cerebral ischemia in mice.

Microvascular endothelial cells from preeclamptic women exhibit altered expression of angiogenic and vasopressor factors

Preeclampsia (PE) is a severe complication of pregnancy associated with maternal and fetal morbidity and mortality. The underlying pathophysiology involves maternal systemic vascular and endothelial dysfunction associated with circulating antiangiogenic factors, although the specific etiology of the disease remains elusive. Our aim was to investigate the maternal endothelium in PE by exploring the expression of genes involved with endothelial function in a novel platform of maternal primary endothelial cells. Adipose tissue was sampled at the time of caesarean section from both normal and preeclamptic patients. Maternal microvascular endothelial cells were isolated by tissue digestion and CD31 magnetic Dynabeads. Cell purity was confirmed by immunofluorescence microscopy and flow cytometry. Western analyses revealed VEGF activation of VEGF receptor 2 (VEGFR2) and ERK in primary cells. Quantitative PCR analyses revealed significantly altered mRNA levels of various genes involved with angiogenesis and blood pressure control in preeclamptic cells, including soluble fms-like tyrosine kinase-1, endoglin, VEGFR2, angiotensin receptor 1, and endothelin compared with cells isolated from normal pregnancies. Overall, maternal endothelial cells from preeclamptic patients exhibit extensive alteration of expression of factors associated with antiangiogenic and vasoconstrictive phenotypes, shedding light on the underlying mechanisms associated with the vascular dysfunction characteristic of PE.