Brain Endothelial miR-146a Negatively Modulates T-Cell Adhesion through Repressing Multiple Targets to Inhibit NF-κB Activation

Abstract

Pro-inflammatory cytokine-induced activation of nuclear factor, NF-κB has an important role in leukocyte adhesion to, and subsequent migration across, brain endothelial cells (BECs), which is crucial for the development of neuroinflammatory disorders such as multiple sclerosis (MS). In contrast, microRNA-146a (miR-146a) has emerged as an anti-inflammatory molecule by inhibiting NF-κB activity in various cell types, but its effect in BECs during neuroinflammation remains to be evaluated. Here, we show that miR-146a was upregulated in microvessels of MS-active lesions and the spinal cord of mice with experimental autoimmune encephalomyelitis. In vitro, TNFα and IFNγ treatment of human cerebral microvascular endothelial cells (hCMEC/D3) led to upregulation of miR-146a. Brain endothelial overexpression of miR-146a diminished, whereas knockdown of miR-146a augmented cytokine-stimulated adhesion of T cells to hCMEC/D3 cells, nuclear translocation of NF-κB, and expression of adhesion molecules in hCMEC/D3 cells. Furthermore, brain endothelial miR-146a modulates NF-κB activity upon cytokine activation through targeting two novel signaling transducers, RhoA and nuclear factor of activated T cells 5, as well as molecules previously identified, IL-1 receptor-associated kinase 1, and TNF receptor-associated factor 6. We propose brain endothelial miR-146a as an endogenous NF-κB inhibitor in BECs associated with decreased leukocyte adhesion during neuroinflammation.

Exploring New Inflammatory Biomarkers and Pathways during LPS-Induced M1 Polarization

“…These data support the acquisition of a M1 phenotype in microglia activated by LPS with the loss of their neuroprotective properties and sustained upregulation of proinflammatory features by the miR-155 regulation networks. Intriguingly, the overexpression of miR-146a may constitute a mechanism of regulating the inflammatory response [56], exemplifying the complexity of the M1/M2/M0 landscape. In addition, we found that N9 cells were able to release exosomes of approximately 160 nm diameter, as determined by DLS analysis (Figure 7(b)).…”

miR-146a suppresses STAT3/VEGF pathways and reduces apoptosis through IL-6 signaling in primary human retinal microvascular endothelial cells in high glucose conditions

“…Predominantly, miR-146a has been implicated as an epigenetic regulator of inflammatory responses. The regulatory roles of miR-146a that affects inflammatory pathways have been shown in various cell types, including human RPE cells (50), trabecular meshwork cells (51), brain endothelial cells (52), brain microglical cells (53), and cells from intervertebral discs (54). Much work has demonstrated that REC are an important cell type substantially affected in diabetic retinopathy (55–57).…”

Endothelial microRNA-150 is an intrinsic suppressor of pathologic ocular neovascularization

“…HRMECs and human embryonic kidney 293T cells (HEK293T; ATCC) were cultured for endothelial functional assays (migration, proliferation, and tube formation) and luciferase assays, respectively. FAMlabeled premiRNA (Ambion) was used to analyze transfection efficiency of miRNAs (52) and showed around 90% transfection efficiency in HRMECs (SI Appendix, Fig. S9).…”