[Expression of acylation stimulating protein receptor (C5L2) in preadipocytes during differentiation and under stimulation of free fatty acids].
OBJECTIVE
To observe the changes of expression of the acylation stimulating protein (ASP) functional receptor C5L2 during adipocytes differentiation, and to study the regulation of C5L2 by free fatty acid (FFA) in cultured adipocytes and preadipocytes.


METHODS
Preadipocytes of the line 3T3-L1 were cultured and induced to differentiate. Oleate or palmitate of the doses 0 - 1.0 mmol/L were added into the cultured fluid of the 3T3-L1 mature adipocytes or preadipocytes overnight. RT-PCR and flow cytometry were used to detect the mRNA and protein expression of C5L2.


RESULTS
The C5L2 mRNA expression level of the adipocytes 9 days after differentiation was 0.89 +/- 0.24, 3.56 times that before induction (0.25 +/- 0.12, P < 0.01). The C5L2 protein expression 6 h after induction was 61% +/- 18%, higher by 21% in comparison of that at the 0 d (51% +/- 15%, P < 0.05), and the C5L2 protein expression 12 h after induction reached a maximal level (70% +/- 12%), 38% higher than that at 0 d (P < 0.01). Then the C5L2 protein expression decreased significantly on the third day after induction to the level on the day 0. The C5L2 mRNA expression levels of the mature adipocytes stimulated by oleate 0.125, 0.5, and 1.0 mmol/L for 18 h were decreased by 6%, 46%, and 84% respectively compared with that of the oleate 0 mmol/L (all P < 0.05); however, the C5L2 mRNA expression levels of the preadipocytes stimulated by oleate 0.125, 0.5, and 1.0 mmol/L for 18 h were not significantly different from that of the oleate 0 mmol/L group. The C5L2 mRNA expression levels of the mature adipocytes stimulated by palmitate 0.125, 0.5, and 1.0 mmol/L for 18 h were decreased suppressed dose-dependently, for example, the C5L2 mRNA expression level of the palmitate 1.0 mmol/L group was lower than that of the palmitate 1.0 mmol/L group by 41% (P < 0.05); however, the C5L2 mRNA expression levels of the palmitate 1.0 mmol/L group was not significantly different from that of the palmitate 0 mmol/L group.


CONCLUSIONS
The ASP/C5L2 pathway plays a role in adipocytes differentiation. Downregulation of C5L2 mRNA and protein may contribute to impaired insulin.
Wen
Yu
Y
Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Wang
Hong-Wei
HW
Wu
Jing
J
Lu
Hui-Ling
HL
Xia
Zhi
Z
Cianflone
Katherine
K
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005230:Fatty Acids, Nonesterified / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D051379:Mice; D019301:Oleic Acid / Q000494:pharmacology; D019308:Palmitic Acid / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044087:Receptor, Anaphylatoxin C5a; D019707:Receptors, Chemokine / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
C000594938:C5ar2 protein, mouse; D005230:Fatty Acids, Nonesterified; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D019707:Receptors, Chemokine; D019301:Oleic Acid; D019308:Palmitic Acid