Low phosphoinositide-specific phospholipase C activity and expression of phospholipase C beta1 protein in the prefrontal cortex of teenage suicide subjects.
OBJECTIVE
The enzyme phosphoinositide-specific phospholipase C (PI-PLC) is a component of the phosphoinositide signal transduction system. Other components of this system have been found to be abnormal in adults and adolescents who have committed suicide, and so the authors examined whether PI-PLC activity and protein expression of PLC isozymes are abnormal in postmortem brains of teenage suicide subjects.


METHODS
PI-PLC activity and protein expression of the PLC beta1, delta1, and gamma1 isozymes were examined in Brodmann's areas 8 and 9 of postmortem brains obtained from 18 teenage suicide subjects and 18 matched comparison subjects. PI-PLC activity was determined by enzymatic assay, and protein expression of the PLC isozymes was determined by the Western blot technique.


RESULTS
Compared with the normal subjects, the teenage suicide subjects had significantly lower PI-PLC activity and immunolabeling of the specific PLC beta1 isozyme in both membrane and cytosol fractions of Brodmann's areas 8 and 9 combined (prefrontal cortex). There was also a significant correlation between PI-PLC activity and protein levels of the PLC beta1 isozyme in the brains of the teenage suicide subjects. There was no significant difference in PI-PLC activity or level of PLC beta1 protein between the suicide subjects with a history of mental disorders and those with no history of mental disorders; however, both groups had significantly lower PI-PLC activity and expression of PLC beta1 protein than the normal subjects.


CONCLUSIONS
Low PI-PLC activity and expressed levels of the PLC beta1 isozyme in postmortem brains of suicide subjects may have clinical relevance in the pathophysiology of suicidal behavior.
Pandey
G N
GN
Psychiatric Institute, Department of Psychiatry, University of Illinois at Chicago, 60612, USA. GNPandey@psych.uic.edu
Dwivedi
Y
Y
Pandey
S C
SC
Teas
S S
SS
Conley
R R
RR
Roberts
R C
RC
Tamminga
C A
CA
D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000523:psychology; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010716:Phosphatidylinositols / Q000378:metabolism; D054801:Phosphoinositide Phospholipase C; D054799:Phospholipase C beta; D017397:Prefrontal Cortex / Q000737:chemistry* / Q000201:enzymology; D000297:Psychology, Adolescent; D044469:Racial Groups; D012919:Social Behavior; D013405:Suicide / Q000706:statistics & numerical data*; D010738:Type C Phospholipases / Q000378:metabolism*
D007527:Isoenzymes; D010716:Phosphatidylinositols; D010738:Type C Phospholipases; C518033:PLCB1 protein, human; D054801:Phosphoinositide Phospholipase C; D054799:Phospholipase C beta; D043265:Phosphatidylinositol Diacylglycerol-Lyase