Regulation of lipid metabolism by Dicer revealed through SILAC mice.
Dicer is a ribonuclease whose major role is to generate mature microRNAs, although additional functions have been proposed. Deletion of Dicer leads to embryonic lethality in mice. To study the role of Dicer in adults, we generated mice in which administration of tamoxifen induces deletion of Dicer. Surprisingly, disruption of Dicer in adult mice induced lipid accumulation in the small intestine. To dissect the underlying mechanisms, we carried out miRNA, mRNA, and proteomic profiling of the small intestine. The proteomic analysis was done using mice metabolically labeled with heavy lysine (SILAC mice) for an in vivo readout. We identified 646 proteins, of which 80 were up-regulated >2-fold and 75 were down-regulated. Consistent with the accumulation of lipids, Dicer disruption caused a marked decrease of microsomal triglyceride transfer protein, long-chain fatty acyl-CoA ligase 5, fatty acid binding protein, and very-long-chain fatty acyl-CoA dehydrogenase, among others. We validated these results using multiple reaction monitoring (MRM) experiments by targeting proteotypic peptides. Our data reveal a previously unappreciated role of Dicer in lipid metabolism. These studies demonstrate that a systems biology approach by integrating mouse models, metabolic labeling, gene expression profiling, and quantitative proteomics can be a powerful tool for understanding complex biological systems.
McKusick-Nathans Institute of Genetic Medicine, Department of Biological Chemistry, Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States.
Tai-Chung
TC
Huang
Nandini A
NA
Sahasrabuddhe
Min-Sik
MS
Kim
Derese
D
Getnet
Yi
Y
Yang
Jonathan M
JM
Peterson
Bidyut
B
Ghosh
Raghothama
R
Chaerkady
Steven D
SD
Leach
Luigi
L
Marchionni
G William
GW
Wong
Akhilesh
A
Pandey
D000818:Animals; D053487:DEAD-box RNA Helicases / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D055786:Gene Knockout Techniques; D005818:Genetic Engineering / Q000379:methods; D006651:Histocytochemistry; D007421:Intestine, Small / Q000378:metabolism / Q000473:pathology; D050356:Lipid Metabolism / Q000235:genetics*; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020543:Proteome / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D015203:Reproducibility of Results; D043244:Ribonuclease III / Q000235:genetics* / Q000378:metabolism
D020543:Proteome; C509781:Dicer1 protein, mouse; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases