Large changes in NAD levels associated with CD38 expression during HL-60 cell differentiation.
NAD is an important cofactor involved in multiple metabolic reactions and as a substrate for several NAD-dependent signalling enzymes. One such enzyme is CD38 which, alongside synthesising Ca(2+)-releasing second messengers and acting as a cell surface receptor, has also been suggested to play a key role in NAD(+) homeostasis. CD38 is well known as a negative prognostic marker in B-CLL but the role of its enzymatic activity has not been studied in depth to date. We have exploited the HL-60 cell line as a model of inducible CD38 expression, to investigate CD38-mediated regulation intracellular NAD(+) levels and the consequences of changes in NAD(+) levels on cell physiology. Intracellular NAD(+) levels fell with increasing CD38 expression and this was reversed with the CD38 inhibitor, kuromanin confirming the key role of CD38 in NAD(+) homeostasis. We also measured the consequences of CD38 expression during the differentiation on a number of functions linked to NAD(+) and we show that some but not all NAD(+)-dependent processes are significantly affected by the lowered NAD(+) levels. These data suggest that both functional roles of CD38 might be important in the pathogenesis of B-CLL.
School of Biological Sciences, Plymouth University, Plymouth PL4 8AA, UK.
Zainab N
ZN
Al-Abady
Barbara
B
Durante
A John
AJ
Moody
Richard A
RA
Billington
D051997:ADP-ribosyl Cyclase 1 / Q000096:biosynthesis* / Q000235:genetics; D002454:Cell Differentiation; D018922:HL-60 Cells; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000378:metabolism / Q000473:pathology*; D009243:NAD / Q000032:analysis / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
D012333:RNA, Messenger; D009243:NAD; D051997:ADP-ribosyl Cyclase 1
CD157; CD38; CLL; HL-60; NAD(P); Pyridine nucleotides