Nuclear factor-?B regulates expression of platelet phospholipase C-?2 (PLCB2).

ABSTRACT: Phospholipase C (PLC)-?2 (gene PLCB2) is a critical regulator of platelet responses upon activation. Mechanisms regulating of PLC-?2 expression in platelets/MKs are unknown. Our studies in a patient with platelet PLC-?2 deficiency revealed the PLCB2 coding sequence to be normal and decreased platelet PLC-?2 mRNA, suggesting a defect in transcriptional regulation. PLCB2 5'- upstream region of the patient revealed a heterozygous 13 bp deletion (-1645/-1633 bp) encompassing a consensus sequence for nuclear factor-?B (NF-?B). This was subsequently detected in three of 50 healthy subjects. To understand the mechanisms regulating PLC-?2, we studied the effect of this variation in the PLCB2. Gel-shift studies using nuclear extracts from human erythroleukaemia (HEL) cells or recombinant p65 showed NF-?B binding to oligonucleotide with NF-?B site; in luciferase reporter studies its deletion reduced PLCB2 promoter activity. PLCB2 expression was decreased by siRNA knockdown of NF-?B p65 subunit and increased by p65 overexpression. By immunoblotting platelet PLC-?2 in 17 healthy subjects correlated with p65 (r=0.76, p=0.0005). These studies provide the first evidence that NF-?B regulates MK/platelet PLC-?2 expression. This interaction is important because of the major role of PLC-?2 in platelet activation and of NF-?B in processes, including inflammation and atherosclerosis, where both are intimately involved.

SUBMITTER: Mao G 

PROVIDER: S-EPMC6919569 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature