Hormone sensitive lipase mRNA in both monocyte and macrophage forms of the human THP-1 cell line.
The identity of the neutral cholesteryl ester hydrolase (CEH) in human monocyte/macrophages is uncertain. Prior studies indicate that hormone sensitive lipase (HSL) is a major CEH in mouse macrophages, and that HSL mRNA is present in human THP-1 monocytes. In the present study, HSL mRNA expression was examined in THP-1 cells as a function of differentiation status and cholesterol enrichment. By RT-PCR with primer pairs that span exon boundaries, HSL mRNA was demonstrated in THP-1 monocytes and phorbol-ester differentiated THP-1 macrophages. cDNA identities were confirmed by sequencing. By Northern blotting, with HSL cDNA as probe, THP-1 monocytes were found to contain HSL mRNA of approximately 3 and 3.9 kb. In THP-1 macrophages, the 3 kb mRNA was greatly diminished, while the level of the 3.9 kb mRNA was maintained. mRNA of approximately 3 and 3.9 kb are those expected of the 86-kDa (adipocyte) and 117-kDa (testicular) HSL isoforms, respectively. The presence of the testicular isoform mRNA was confirmed in THP-1 cells by amplification and sequencing of an isoform-specific cDNA. Additionally, Northern-blot comparisons showed that the 3 and 3.9 kb mRNA in THP-1 comigrated with the HSL mRNA in 3T3-L1 adipocytes and rat testis, respectively. The level of the 3.9 kb mRNA did not vary greatly with cholesterol enrichment. Thus, the HSL gene is transcribed in THP-1 cells both before and after differentiation into macrophages; after differentiation, the predominant mRNA is that for the 117-kDa isoform. This isoform is a CEH, and may mediate some CE turnover in THP-1 cells.
Johnson
W J
WJ
Abramson Research Center, Joseph Stokes, Jr, Research Institute, Children's Hospital of Philadelphia, PA 19104, USA. johnsonw@email.chop.edu
Jang
S Y
SY
Bernard
D W
DW
D015152:Blotting, Northern; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D009000:Monocytes / Q000201:enzymology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D002787:Sterol Esterase / Q000235:genetics* / Q000378:metabolism; D013737:Testis / Q000201:enzymology / Q000378:metabolism; D014407:Tumor Cells, Cultured
D007527:Isoenzymes; D012333:RNA, Messenger; D002787:Sterol Esterase