Viral encephalitis
Prof T Solomon & Dr L Hubble
Liverpool University
2008 – 2011 Postdoctoral Fellowship
Development of a human ex vivo blood brain barrier model to study viral encephalitis.
Prof Tom Solomon is Professor of Neurological Science at Liverpool University and Honorary Consultant Neurologist at the Walton Centre for Neurology & Neurosurgery and Royal Liverpool University Hospital.
Dr Leman Hubble is an Academic Clinical Fellow at Liverpool and Broadgreen University Hospitals, Liverpool.
Viral encephalitis is an important type of neurological infection and has a devastating impact on the quality of life of those affected. Japanese encephalitis virus (JEV) is one of the most common causes of viral encephalitis globally. Like the closely related flavivirus, West Nile virus (WNV), it is spreading, and there is no known treatment.
One of the key events in the pathogenesis of any viral encephalitis is the means by which virus crosses the blood brain barrier (BBB), and the role of pro-inflammatory cytokines in BBB disruption. Typically such questions are addressed in animals, but newer human ex vivo BBB models are becoming available.
Animal studies of JEV and other flaviviruses have included inoculation of Rhesus monkeys that caused animals to suffer depression, anorexia, tremors, paralysis, coma and death. More commonly mice are used to study JEV and WNV with signs of infection being leg paralysis, a hunched back, ruffled fur, minimal activity, and sometimes seizures.
There are some important differences between human material and that from mice, so a robust model of the human BBB, which allowed viral interactions at this important interface to be studied, would by scientifically preferable and obviate the need for much of the current work on viral encephalitis in the rodent models.
The immediate objective of this Dr Hadwen Trust-funded project is to establish a robust, working ex-vivo model of the human blood brain barrier to examine the mechanisms of viral entry into the nervous system in place of animal studies. The second phase of the project will focus more specifically on JEV.
The starting point for this project is an established model of the BBB using transformed human brain microvascular endothelial cells [1]. Attempts will be made to develop better models: one of these will use primary brain endothelial cells which are likely to be phenotypically more accurate; and in the other model brain endothelial and astrocytic cells will be co-cultured, which is structurally closer to the actual BBB in humans.
These models will be used in place of animal studies to examine the mechanisms by which virus crosses the BBB, looking for evidence of viral replication in endothelial cells, pro-inflammatory cytokine production. Their effects on BBB integrity will be determined by assessing solute permeability and immunohistochemical analysis. The project will also examine the role of broad and targeted immunomodulatory treatments, which have important therapeutic implications.
Reference
1. Muruganandam A, Herx LM, Monette R et al (1997). Development of immortalised human cerebromicrovascular endothelial cell line as an in vitro model of the human blood-brain barrier. FASEB J 11:1187-1197.