Transmigration across a Steady-State Blood–Brain Barrier Induces Activation of Circulating Dendritic Cells Partly Mediated by Actin Cytoskeletal Reorganization

Abstract

The central nervous system (CNS) is considered to be an immunologically unique site, in large part given its extensive protection by the blood–brain barrier (BBB). As our knowledge of the complex interaction between the peripheral immune system and the CNS expands, the mechanisms of immune privilege are being refined. Here, we studied the interaction of dendritic cells (DCs) with the BBB in steady–state conditions and observed that transmigrated DCs display an activated phenotype and stronger T cell-stimulatory capacity as compared to non-migrating DCs. Next, we aimed to gain further insights in the processes underlying activation of DCs following transmigration across the BBB. We investigated the interaction of DCs with endothelial cells as well as the involvement of actin cytoskeletal reorganization. Whereas we were not able to demonstrate that DCs engulf membrane fragments from fluorescently labelled endothelial cells during transmigration across the BBB, we found that blocking actin restructuring of DCs by latrunculin-A significantly impaired in vitro migration of DC across the BBB and subsequent T cell-stimulatory capacity, albeit no effect on migration-induced phenotypic activation could be demonstrated. These observations contribute to the current understanding of the interaction between DCs and the BBB, ultimately leading to the design of targeted therapies capable to inhibit autoimmune inflammation of the CNS.

Study of BBB Dysregulation in Neuropathogenicity Using Integrative Human Model of Blood–Brain Barrier

“…In contrast, T lymphocytes did not affect the properties of HBMECs (Wong et al, 1999). Transmigration of dendritic cells has been associated with the restructuring of endothelial cell actin in a transwell model of hCMEC/D3 cultured with astrocytes (Meena et al, 2021).…”

A Microfluidic In Vitro Three-Dimensional Dynamic Model of the Blood–Brain Barrier to Study the Transmigration of Immune Cells

“…As a control, the static in vitro BBB model was constructed as described previously [ 43 , 44 ]. In brief, human primary astrocytes (Sanbio) were seeded at a density of 15,000 cells/cm 2 on the poly-L-lysine-coated samples outside of a 24-well transwell with a 3.0 µm pore size (Polyethylene terephthalate, Greiner Bio-one) and were allowed to adhere for 2 h. The transwell insert was transferred into a 24-well plate filled with EGM-2-MV medium (Lonza) supplemented with 2.5% FBS (Thermo Fisher Scientific).…”

VLA-4 suppression by senescence signals regulates meningeal immunity and leptomeningeal metastasis

“…Murine brain microvascular endothelial cells (MBMECs) were isolated as previously described (37,38). In brief, mice were sacrificed and meninge-free forebrains were collected, minced, then digested with 10 mg/mL of collagenase II and 1 mg/mL DNase(Worthington Biochemical) in DMEM in a shaker for 1 h at 37 °C.…”