POSTER
VIRAL MICROARRAY
STUDIES: RETROVIRUSES
Concepcion Conejero-Goldberg1, Ena Wang2, Chuli Yi1,
Terry Goldberg3, Francesco M. Marincola2, Lorraine
Jones-Brando4, Maree J. Webster1, Robert H. Yolken4,
and E. Fuller Torrey1
1Stanley
Medical Research Institute, 2Department of Transfusion Medicine,
National Institutes of Health, 3Clinical Brain Disorders Branch,
National Institutes of Health, 4Stanley Division of Developmental
Neurovirology, Johns Hopkins University School of Medicine
Microarray technology has
become an important tool in psychiatric research. Evidence that links HERVs to
schizophrenia comes from the detection of increased expression of sequences
homologous to retroviruses in both cerebrospinal fluid and brain tissue from
patients with schizophrenia.
A unique array based
pathogen chip has been developed in our laboratory for the detection of viral
RNA expression levels or DNA prevalence from test samples. A set of long
oligonucleotides (60-mer) was designed based on highly conserved regions within
viral families, as well as heterogenic regions characterized by individual
subfamilies. In addition, by including oligonucleotides derived from genes
implicated in different stages of the infection, we were also able to
potentially define the stage of the viral infection. To validate the viral
microarray we used virally infected cell cultures to detect and identify diverse
viruses and their infectious stage.
Total RNA from Brodmann
area 46, from 8 patients with schizophrenia and 10 unaffected controls was
linearly amplified using in vitro transcription in combination with a template
switch technique. Samples were then examined by cohybridization of patient aRNA
labeled with Cy5 (red) with pooled control aRNA labeled with Cy3 (green) to the
pathogen microarray chip. The expression of 51 genes displayed statistically
significant differences between schizophrenic cases and controls P<.05 b t-test). Expression of 6 viral sequences differed between groups by X2
(using a 1 SD cut off). All favored increased levels of expression in the
schizophrenia cases. More specifically, we found evidence of increased
expression of a sequence homologous to the endogenous retrovirus HERVWE1 in the
schizophrenic group using both statistical methods. Quantitative-PCR studies
are underway to validate these results.
These findings suggest that
this platform provides the capability to detect a broad spectrum of viruses in a
single assay while simultaneously discriminating among different stages of the
viruses. This method may be applied to identify evidence of viral infection in
postmortem tissue from psychiatric patients as well as a wide range of other
diagnostic categories.