Interleukin-1β induces blood-brain barrier disruption by downregulating Sonic hedgehog in astrocytes

PLoS One. 2014 Oct 14;9(10):e110024. doi: 10.1371/journal.pone.0110024. eCollection 2014.

Abstract

The blood-brain barrier (BBB) is composed of capillary endothelial cells, pericytes, and perivascular astrocytes, which regulate central nervous system homeostasis. Sonic hedgehog (SHH) released from astrocytes plays an important role in the maintenance of BBB integrity. BBB disruption and microglial activation are common pathological features of various neurologic diseases such as multiple sclerosis, Parkinson's disease, amyotrophic lateral sclerosis, and Alzheimer's disease. Interleukin-1β (IL-1β), a major pro-inflammatory cytokine released from activated microglia, increases BBB permeability. Here we show that IL-1β abolishes the protective effect of astrocytes on BBB integrity by suppressing astrocytic SHH production. Astrocyte conditioned media, SHH, or SHH signal agonist strengthened BBB integrity by upregulating tight junction proteins, whereas SHH signal inhibitor abrogated these effects. Moreover, IL-1β increased astrocytic production of pro-inflammatory chemokines such as CCL2, CCL20, and CXCL2, which induce immune cell migration and exacerbate BBB disruption and neuroinflammation. Our findings suggest that astrocytic SHH is a potential therapeutic target that could be used to restore disrupted BBB in patients with neurologic diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / metabolism*
  • Blood-Brain Barrier / metabolism*
  • Cell Line
  • Chemokines / genetics
  • Chemokines / metabolism
  • Down-Regulation
  • Gene Expression
  • Hedgehog Proteins / genetics
  • Hedgehog Proteins / metabolism*
  • Interleukin-1beta / physiology*
  • Mice
  • Paracrine Communication
  • Tight Junctions / metabolism

Substances

  • Chemokines
  • Hedgehog Proteins
  • IL1B protein, mouse
  • Interleukin-1beta
  • Shh protein, mouse

Grants and funding

This work was supported in part by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan; a grant from the Advanced Research for Medical Products Mining Program of the National Institute of Biomedical Innovation (NIBIO) of Japan; and grants from the Ministry of Health, Labour and Welfare of Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.