TY - JOUR
T1 - Selection of reference gene expression in a schizophrenia brain cohort
AU - Weickert, Cynthia Shannon
AU - Sheedy, Donna
AU - Rothmond, Debora A.
AU - Dedova, Irina
AU - Fung, Samantha
AU - Garrick, Therese
AU - Wong, Jenny
AU - Harding, Antony J.
AU - Sivagnanansundaram, Sinthuja
AU - Hunt, Clare
AU - Duncan, Carlotta
AU - Sundqvist, Nina
AU - Tsai, Shan Yuan
AU - Anand, Jasna
AU - Draganic, Daren
AU - Harper, Clive
PY - 2010/1
Y1 - 2010/1
N2 - Objective: In order to conduct postmortem human brain research into the neuropatho-logical basis of schizophrenia, it is critical to establish cohorts that are well-characterized and well-matched. The aim of the present study was therefore to determine if specimen characteristics including: diagnosis, age, postmortem interval (PMI), brain acidity (pH), and/or the agonal state of the subject at death related to RNA quality, and to determine the most appropriate reference gene mRNAs. Methods: A matched cohort was selected of 74 subjects (schizophrenia/schizoaffective disorder, n 37; controls, n 37). Middle frontal gyrus tissue was pulverized, tissue pH was measured, RNA isolated for cDNA from each case, and RNA integrity number (RIN) measurements were assessed. Using quantitative reverse transcriptionpolymerase chain reaction, nine housekeeper genes were measured and a geomean calculated per case in each diagnostic group. Results: The RINs were very good (mean 7.3) and all nine housekeeper control genes were significantly correlated with RIN. Seven of nine housekeeper genes were also correlated with pH; two clinical variables, agonal state and duration of illness, did have an effect on some control mRNAs. No major impact of PMI or freezer time on housekeeper mRNAs was detected. The results show that people with schizophrenia had significantly less PPIA and SDHA mRNA and tended to have less GUSB and B2M mRNA, suggesting that these control genes may not be good candidates for normalization. Conclusions: In the present cohort <10% variability in RINs was detected and the diagnostic groups were well matched overall. The cohort was adequately powered (0.800.90) to detect mRNA differences (25%) due to disease. The study suggests that multiple factors should be considered in mRNA expression studies of human brain tissues. When schizophrenia cases are adequately matched to control cases subtle differences in gene expression can be reliably detected.
AB - Objective: In order to conduct postmortem human brain research into the neuropatho-logical basis of schizophrenia, it is critical to establish cohorts that are well-characterized and well-matched. The aim of the present study was therefore to determine if specimen characteristics including: diagnosis, age, postmortem interval (PMI), brain acidity (pH), and/or the agonal state of the subject at death related to RNA quality, and to determine the most appropriate reference gene mRNAs. Methods: A matched cohort was selected of 74 subjects (schizophrenia/schizoaffective disorder, n 37; controls, n 37). Middle frontal gyrus tissue was pulverized, tissue pH was measured, RNA isolated for cDNA from each case, and RNA integrity number (RIN) measurements were assessed. Using quantitative reverse transcriptionpolymerase chain reaction, nine housekeeper genes were measured and a geomean calculated per case in each diagnostic group. Results: The RINs were very good (mean 7.3) and all nine housekeeper control genes were significantly correlated with RIN. Seven of nine housekeeper genes were also correlated with pH; two clinical variables, agonal state and duration of illness, did have an effect on some control mRNAs. No major impact of PMI or freezer time on housekeeper mRNAs was detected. The results show that people with schizophrenia had significantly less PPIA and SDHA mRNA and tended to have less GUSB and B2M mRNA, suggesting that these control genes may not be good candidates for normalization. Conclusions: In the present cohort <10% variability in RINs was detected and the diagnostic groups were well matched overall. The cohort was adequately powered (0.800.90) to detect mRNA differences (25%) due to disease. The study suggests that multiple factors should be considered in mRNA expression studies of human brain tissues. When schizophrenia cases are adequately matched to control cases subtle differences in gene expression can be reliably detected.
KW - Housekeeping genes
KW - pH
KW - Postmortem brain
KW - Postmortem interval
KW - RNA integrity number
UR - http://www.scopus.com/inward/record.url?scp=75149163414&partnerID=8YFLogxK
U2 - 10.3109/00048670903393662
DO - 10.3109/00048670903393662
M3 - Article
C2 - 20073568
AN - SCOPUS:75149163414
SN - 0004-8674
VL - 44
SP - 59
EP - 70
JO - Australian and New Zealand Journal of Psychiatry
JF - Australian and New Zealand Journal of Psychiatry
IS - 1
ER -