Inhibition of MicroRNA‐155 Supports Endothelial Tight Junction Integrity Following Oxygen‐Glucose Deprivation

Abstract

BackgroundBrain microvascular endothelial cells form a highly selective blood brain barrier regulated by the endothelial tight junctions. Cerebral ischemia selectively targets tight junction protein complexes, which leads to significant damage to cerebral microvasculature. Short noncoding molecules called microRNAs are implicated in the regulation of various pathological states, including endothelial barrier dysfunction. In the present study, we investigated the influence of microRNA‐155 (miR‐155) on the barrier characteristics of human primary brain microvascular endothelial cells (HBMECs).Methods and ResultsOxygen‐glucose deprivation was used as an in vitro model of ischemic stroke. HBMECs were subjected to 3 hours of oxygen‐glucose deprivation, followed by transfections with miR‐155 inhibitor, mimic, or appropriate control oligonucleotides. Intact normoxia control HBMECs and 4 oxygen‐glucose deprivation–treated groups of cells transfected with appropriate nucleotide were subjected to endothelial monolayer electrical resistance and permeability assays, cell viability assay, assessment of NO and human cytokine/chemokine release, immunofluorescence microscopy, Western blot, and polymerase chain reaction analyses. Assessment of endothelial resistance and permeability demonstrated that miR‐155 inhibition improved HBMECs monolayer integrity. In addition, miR‐155 inhibition significantly increased the levels of major tight junction proteins claudin‐1 and zonula occludens protein‐1, while its overexpression reduced these levels. Immunoprecipitation and colocalization analyses detected that miR‐155 inhibition supported the association between zonula occludens protein‐1 and claudin‐1 and their stabilization at the HBMEC membrane. Luciferase reporter assay verified that claudin‐1 is directly targeted by miR‐155.ConclusionsBased on these results, we conclude that miR‐155 inhibition–induced strengthening of endothelial tight junctions after oxygen‐glucose deprivation is mediated via its direct target protein claudin‐1.

RETRACTED ARTICLE: Bilobalide protects H9c2 cell from oxygen-glucose-deprivation-caused damage via upregulation of miR-27a

“…OGD stimulation often triggers the aberrant miRNAs expression, like miR-7 [41], miR-155 [42], miR-132 [43], miR-27a [21]. Interestingly, Cai et al found that miR-27a overexpression attenuated OGD-induced injury in hippocampal neurons [21], which was consistent with our results.…”

Gap Junctions between Endothelial Cells Are Disrupted by Circulating Extracellular Vesicles from Sickle Cell Patients with Acute Chest Syndrome

“…As small EVs contain microRNAs, and because the effects that we observed took days (24–48 h), it is tempting to suggest that microRNAs from the EVs entered the target endothelial cells and led to gene expression changes for the different junction proteins. There have been a number of previous papers showing that microRNAs affect the expression of adherens and tight junction proteins in endothelial cells [ 29 , 30 , 31 , 32 , 33 , 34 ]. Although, not extensively studied in endothelial cells, there is strong evidence that several microRNAs (including miR-1, miR-130a, miR-206, and others) can downregulate Cx43 [ 35 , 36 , 37 ].…”

Role of endothelial microRNA 155 on capillary leakage in systemic inflammation

“…First, Han et al reported increased circulating MIR155 levels in human sepsis [ 21 ]. Second, Pena-Philippides et al implicated MIR155 in the regulation of endothelial tight junctions after cerebral ischemia [ 22 ]. Specifically, they reported that inhibition of MIR155 fortified monolayers of human primary brain microvascular endothelial cells against barrier breakdown following oxygen–glucose deprivation.…”