Tmic-08. Claudin-1 Upregulation in Glioblastoma Induced Blood-brain-barrier Dysfunction Via a Paracrine Mechanism
Year: 2023
Type: conference-abstract
Abstract: BACKGROUND Blood-brain-barrier (BBB) disruption is a well-known phenomenon in glioblastoma. However, the mechanism driving BBB dysfunction in GBM is still unknown, especially in the previously established vasculature near the invasive edge. In this study, we aimed to determine if GBM paracrine signaling is sufficient to induce BBB dysfunction and identify changes in the tight junctions of the BBB. METHODS An in vivo xenograft model was established through an intracranial injection of U-87 MG cells in nude mice. Weekly MRIs were performed to monitor tumor growth. Two weeks after tumor appearance, brains were collected following a 4% PFA perfusion for immunostaining and confocal imaging. An in vitro model of the BBB was created by seeding primary mouse brain microvascular endothelial cells (BMECs) on transwell inserts. Once the BMECs reached confluency with a TEER value of 170-175Ω*cm2, the media was replaced with filtered conditioned media from U-87 MG cell line, an IDH mutant cell line, or BMECs for three days with TEER values monitored each day. RESULTS Immunofluorescent staining revealed a significant increase in claudin-1 expression and decrease in claudin-5 expression in the tumor vs normal brain tissue of our in vivo model (p < 0.01). After 24 hours of exposure to conditioned media from both U-87 MG and IDH mutant cells, BMECs had a significant decrease in TEER compared to control and BMEC conditioned media (p < .0001). After 72 hours, TEER values continued to decrease, reaching around 155Ω*cm2, with control BMECs remaining around 187Ω*cm2. CONCLUSIONS These results suggest GBM cells secrete factors capable of inducing changes in the tight junction proteins of the BBB and increasing its permeability. Future studies will aim to identify the mechanism in which these changes occur.
Source: Neuro-Oncology
Authors: Brittany Schweiger, Forrest Kievit
Institution: University of Nebraska–Lincoln
Language: English
Subfield: Neurology
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W4388590678