TY - JOUR
T1 - Peroxisome proliferator-activated receptor delta regulates lipid droplet formation and transport in goat mammary epithelial cells
AU - Shi, H. B.
AU - Zhang, C. H.
AU - Xu, Z. A.
AU - Lou, G. G.
AU - Liu, J. X.
AU - Luo, J.
AU - Loor, J. J.
N1 - Funding Information:
This research was jointly supported by a National Natural Science Foundation of China (31702090, Beijing, China), Open Fund of Zhejiang Provincial Top Key Discipline of Biology (Hangzhou, China), and a Special Fund for Agro-Scientific Research in the Public Interest of Zhejiang Province (2016C32061, Hangzhou, China).
Publisher Copyright:
© 2018 American Dairy Science Association
PY - 2018/3
Y1 - 2018/3
N2 - Even though recent evidence in goat mammary epithelial cells (GMEC) suggest a role of peroxisome proliferator-activated receptor delta (PPARD) in regulating lipid homeostasis, its role is not fully understood. Our hypothesis was that PPARD regulates lipid transport processes in GMEC and, thus, plays a crucial role in regulating fat formation. The PPARD was overexpressed using an adenovirus system (Ad-PPARD) with recombinant green fluorescent protein (Ad-GFP) as the control. Results revealed that overexpression of PPARD markedly upregulated the mRNA abundance of PPARD. Compared with the control (Ad-GFP+dimethyl sulfoxide), overexpression of PPARD alone had no effect on mRNA expression of CD36, SCD1, FABP4, ACSL1, and ADRP. The cultures overexpressing PPARD with the PPARD ligand GW0742 (GW) upregulated the expression of CD36, FABP3, FABP4, ACSL1, and ADRP. Overexpression of PPARD in GMEC plus GW increased the concentration of 16:1 and 18:1-trans and was associated with upregulation of SCD1. Compared with the control (Ad-GFP+dimethyl sulfoxide), the decrease of triacylglycerol concentration coupled with upregulation of genes related to lipid droplet secretion (e.g., ADRP and ACSL1) induced by PPARD overexpression suggests a role in lipid droplet (LD) secretion. Luciferase assay revealed that GW increased the ADRP promoter activity in a dose-dependent manner. Knockdown of PPARD impaired the increase of ADRP promoter activity induced by GW, whereas GW enhanced the activity of ADRP promoter in GMEC overexpressing PPARD. Data with the ADRP 5′-flanking truncated luciferase reporter suggest a core region (−1,444 to −990 bp) response element for the induction of GW. This core region contains a known PPARG response element (PPRE) at −1,003 to −990 bp. When the PPRE was mutated, the overexpression of PPARD had no effect on ADRP promoter activity. Collectively, these results reveal a novel role for PPARD in lipid homeostasis via promoting fatty acid transport and LD formation through a mechanism of direct binding to the promoter of key genes. Hence, PPARD activity may contribute to fatty acid transport and LD formation during lactation.
AB - Even though recent evidence in goat mammary epithelial cells (GMEC) suggest a role of peroxisome proliferator-activated receptor delta (PPARD) in regulating lipid homeostasis, its role is not fully understood. Our hypothesis was that PPARD regulates lipid transport processes in GMEC and, thus, plays a crucial role in regulating fat formation. The PPARD was overexpressed using an adenovirus system (Ad-PPARD) with recombinant green fluorescent protein (Ad-GFP) as the control. Results revealed that overexpression of PPARD markedly upregulated the mRNA abundance of PPARD. Compared with the control (Ad-GFP+dimethyl sulfoxide), overexpression of PPARD alone had no effect on mRNA expression of CD36, SCD1, FABP4, ACSL1, and ADRP. The cultures overexpressing PPARD with the PPARD ligand GW0742 (GW) upregulated the expression of CD36, FABP3, FABP4, ACSL1, and ADRP. Overexpression of PPARD in GMEC plus GW increased the concentration of 16:1 and 18:1-trans and was associated with upregulation of SCD1. Compared with the control (Ad-GFP+dimethyl sulfoxide), the decrease of triacylglycerol concentration coupled with upregulation of genes related to lipid droplet secretion (e.g., ADRP and ACSL1) induced by PPARD overexpression suggests a role in lipid droplet (LD) secretion. Luciferase assay revealed that GW increased the ADRP promoter activity in a dose-dependent manner. Knockdown of PPARD impaired the increase of ADRP promoter activity induced by GW, whereas GW enhanced the activity of ADRP promoter in GMEC overexpressing PPARD. Data with the ADRP 5′-flanking truncated luciferase reporter suggest a core region (−1,444 to −990 bp) response element for the induction of GW. This core region contains a known PPARG response element (PPRE) at −1,003 to −990 bp. When the PPRE was mutated, the overexpression of PPARD had no effect on ADRP promoter activity. Collectively, these results reveal a novel role for PPARD in lipid homeostasis via promoting fatty acid transport and LD formation through a mechanism of direct binding to the promoter of key genes. Hence, PPARD activity may contribute to fatty acid transport and LD formation during lactation.
KW - perilipin
KW - peroxisome proliferator-activated receptor response element
KW - promoter
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U2 - 10.3168/jds.2017-13543
DO - 10.3168/jds.2017-13543
M3 - Article
C2 - 29331469
AN - SCOPUS:85040219208
SN - 0022-0302
VL - 101
SP - 2641
EP - 2649
JO - Journal of Dairy Science
JF - Journal of Dairy Science
IS - 3
ER -