title: Spermidine is indispensable in differentiation of 3T3-L1 fibroblasts to adipocytes.
abstract: Impaired adipogenesis has been shown to predispose to disturbed adipocyte function and development of metabolic abnormalities. Previous studies indicate that polyamines are essential in the adipogenesis in 3T3-L1 fibroblasts. However, the specific roles of individual polyamines during adipogenesis have remained ambiguous as the natural polyamines are readily interconvertible inside the cells. Here, we have defined the roles of spermidine and spermine in adipogenesis of 3T3-L1 cells by using (S')- and (R')- isomers of alpha-methylspermidine and (S,S')-, (R,S)- and (R,R')-diastereomers of alpha,omega-bismethylspermine. Polyamine depletion caused by alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, prevented adipocyte differentiation by suppressing the expression of its key regulators, peroxisome proliferator-activated receptor gamma and CCAAT/enhancer binding protein alpha. Adipogenesis was restored by supplementation of methylspermidine isomers but not of bismethylspermine diastereomers. Although both spermidine analogues supported adipocyte differentiation only (S)-methylspermidine was able to fully support cell growth after extended treatment with alpha-DFMO. The distinction between the spermidine analogues in maintaining growth was found to be in their different capability to maintain functional hypusine synthesis. However, the differential ability of spermidine analogues to support hypusine synthesis did not correlate with their ability to support differentiation. Our results show that spermidine, but not spermine, is essential for adipogenesis and that the requirement of spermidine for adipogenesis is not strictly associated with hypusine modification. The involvement of polyamines in the regulation of adipogenesis may offer a potential application for the treatment of dysfunctional adipocytes in patients with obesity and metabolic syndrome.
authors.affiliation: A.I. Virtanen Institute for Molecular Sciences, Biocenter Kuopio, University of Kuopio, Kuopio, Finland.
authors.forename: Susanna
authors.initials: S
authors.lastname: Vuohelainen
authors.forename: Eija
authors.initials: E
authors.lastname: Pirinen
authors.forename: Marc
authors.initials: M
authors.lastname: Cerrada-Gimenez
authors.forename: Tuomo A
authors.initials: TA
authors.lastname: Keinänen
authors.forename: Anne
authors.initials: A
authors.lastname: Uimari
authors.forename: Marko
authors.initials: M
authors.lastname: Pietilä
authors.forename: Alex R
authors.initials: AR
authors.lastname: Khomutov
authors.forename: Juhani
authors.initials: J
authors.lastname: Jänne
authors.forename: Leena
authors.initials: L
authors.lastname: Alhonen
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D050156:Adipogenesis / Q000187:drug effects / Q000235:genetics; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D000518:Eflornithine / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D007536:Isomerism; D050356:Lipid Metabolism / Q000187:drug effects; D051379:Mice; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D011700:Putrescine / Q000031:analogs & derivatives / Q000494:pharmacology; D013095:Spermidine / Q000031:analogs & derivatives / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D051275:Glucose Transporter Type 4; C495693:Slc2a4 protein, mouse; C073193:1-methylspermidine; C044445:MDL 72527; D013095:Spermidine; D011700:Putrescine; D000518:Eflornithine