Neuropeptide Y Regulates Leptin Signaling Pathway via Receptor Y2 Assessed by Microarray in Human Macrophages

Aims: It has been repored that neuropeptide Y receptor Y2 (Y2R) is involved in stress- and high caloric diet-induced metabolic syndrome in mice. Our previous report indicated the association between SNPs of Y2R gene upstream and plasma HDL-cholesterol levels in healthy subjects (rs6857530: GG<GA<AA or rs6857715: TT<TC<CC). Human macrophage differentiated from THP-

1 cells revealed the luciferase activity when transfected with pGL3 -Basic vector inserted by promoter region of Y2R containing rs6857530AA plus rs6857715CC but not by rs6857530GG plus rs6857715TT. This study was carried out to clarify the mechanism of the association between SNPs of Y2R gene upstream and plasma HDL-cholesterol levels.

Methodology: Y2R gene upstream included heterozygous rs6857530 (G/A) and rs6857715 (T/C) in macrophage/THP-1 cells by direct sequencing. Thus, the experiment was carried out to investigate the effect of potent Y2R antagonist BIIE0246 on gene expression in cultured macrophage/THP-1 cells using microarray.

Results: BIIE0246 up-regulated 60 transcripts (>2.0-fold) and down-regulated 55 entities (<0.5-fold) among 60,000 probe sets. It is of interest that leptin receptor gene was up-regulated (2.83-fold) by BIIE0246. BIIE0246-induced up- and down-regulation of gene expression indicated 6 and 1 gene ontology terms, respectively (P<0.001), and 7 pathways including leptin signaling and 1 pathway, respectively (P<0.01).

Conclusion: BIIE0246 regulated several genes and pathways including leptin signaling in macrophage/THP-1 cells. Taken together with the previous report by others, NPY might stimulate cholesterol efflux through Y2R by inhibiting leptin signaling in macrophage/THP-1 cells. Results were consistent with our previous reports indicating higher plasma HDL-cholesterol levels in subjects with Y2R expressive SNPs rs6857530AA plus rs6857715CC in macrophage.