Differential display analysis of gene expression in brains from hepatitis C-infected patients

Hepatitis C virus (HCV) infection is often associated with cognitive dysfunction, fatigue and depression. The current study was undertaken to determine whether HCV infection affects gene expression in brain tissue.

We analysed the gene expression pattern in brain tissue in a group of HCV-infected patients compared with HCV-negative controls.

Brain tissue samples were obtained at autopsy from three HCV-positive patients and three HCV-negative control patients. The analysis of gene expression was conducted using differential display and reverse Northern hybridization. Only those genes that were up or downregulated more than 1.8 times were considered to be differentially expressed.

Altogether, 29 differentially expressed genes were identified by differential display and subsequently confirmed by reverse Northern hybridization. A prominent finding was the downregulation of mitochondrial oxidative phosphorylation genes in HCV-infected patients. The impairment of brain oxidative/energy metabolism has previously been suggested to be the proximate cause of many disorders that impair mentation. Another finding was the downregulation of some ribosomal protein genes and several genes involved in transcription regulation, perhaps reflecting reduced metabolic activities.

Our findings suggest for the first time that there may be a biological basis for the neuropsychiatric symptoms and cognitive impairment associated with HCV infection.