Altered IMPA2 gene expression and calcium homeostasis in bipolar disorder.

Abstract

Reduced inositol monophosphatase (IMPase) activity and elevated basal intracellular calcium levels ([Ca(2+)](B)) have been reported in B lymphoblast cell lines (BLCLs) from bipolar I affective disorder (BD-I) patients, which may reflect cellular endophenotypes of this disorder. As the PI cycle couples to intracellular Ca(2+) mobilization, these two putative endophenotypes may be related. Using an RT-PCR assay, mRNA levels were estimated for IMPA1 and 2 genes encoding human IMPase 1 and 2, respectively, in BLCLs phenotyped on [Ca(2+)](B), from patients with a DSM-IV diagnosis of BD-I (n = 12 per phenotype) and from age- and sex-matched healthy subjects (n = 12). IMPA2 mRNA levels were significantly lower in BLCLs from male BD-I patients with high [Ca(2+)](B) (n = 6) compared with healthy male subjects (n = 5) (-52%, P = 0.013), male BD-I patients with normal BLCL [Ca(2+)](B) (n = 8) (-42%, P = 0.003) and female BD-I patients with high [Ca(2+)](B) (n = 6) (-59%, P = 0.0004). A significant negative correlation was observed between IMPA2 mRNA levels and [Ca(2+)](B) in BLCLs from male (P = 0.046), but not female BD-I patients. Sex-dependent differences were also evident in postmortem temporal cortex IMPA2 mRNA levels which, in contrast to BLCLs, were significantly higher in male BD-I subjects compared with male controls (P = 0.025, n = 4/group). Collectively, these observations suggest a potential sex-dependent link between abnormalities in IMPA2 expression and calcium homeostasis in the pathophysiology of BD.

• Authors: I S Yoon, P P Li, K P Siu, J L Kennedy, R G Cooke, S V Parikh, J J Warsh
• Journal: Molecular psychiatry (Mol Psychiatry) Vol. 6 Issue 6 Pg. 678-83 (Nov 2001) ISSN: 1359-4184 [Print] England
• PMID: 11673796 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• RNA, Messenger
• Lithium
• Phosphoric Monoester Hydrolases
• myo-inositol-1 (or 4)-monophosphatase
• Calcium

Topics

• Adult
• B-Lymphocytes (metabolism)
• Bipolar Disorder (drug therapy, genetics, metabolism)
• Calcium (metabolism)
• Female
• Gene Expression
• Homeostasis (genetics)
• Humans
• Lithium (therapeutic use)
• Male
• Middle Aged
• Phosphoric Monoester Hydrolases (genetics, metabolism)
• RNA, Messenger (analysis)
• Signal Transduction (genetics)
• Temporal Lobe (metabolism)