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Targeting FoxO1 with AS1842856 suppresses adipogenesis.

Zou P, Liu L, Zheng L, Liu L, Stoneman RE, Cho A, Emery A, Gilbert ER, Cheng Z - Cell Cycle (2014)

Bottom Line: As FoxO1 has been implicated in adipogenic regulation, we investigated the kinetics of FoxO1 activation during adipocyte differentiation, and tested the effects of FoxO1 antagonist (AS1842856) on adipogenesis.We found for the first time that the kinetics of FoxO1 activation follows a series of sigmoid curves, and reveals the phases relevant to clonal expansion, cell cycle arrest, and the regulation of PPARγ, adiponectin, and mitochondrial proteins (complexes I and III).Importantly, persistent inhibition of FoxO1 with AS1842856 almost completely suppressed adipocyte differentiation, while selective inhibition in specific stages had differential effects on adipogenesis.

View Article: PubMed Central - PubMed

Affiliation: a Department of Human Nutrition, Foods and Exercise; Fralin Life Science Institute; College of Agriculture and Life Science; Virginia Tech , Blacksburg , VA USA.

ABSTRACT
Hyperplasia (i.e., increased adipogenesis) contributes to excess adiposity, the hallmark of obesity that can trigger metabolic complications. As FoxO1 has been implicated in adipogenic regulation, we investigated the kinetics of FoxO1 activation during adipocyte differentiation, and tested the effects of FoxO1 antagonist (AS1842856) on adipogenesis. We found for the first time that the kinetics of FoxO1 activation follows a series of sigmoid curves, and reveals the phases relevant to clonal expansion, cell cycle arrest, and the regulation of PPARγ, adiponectin, and mitochondrial proteins (complexes I and III). In addition, multiple activation-inactivation transitions exist in the stage of terminal differentiation. Importantly, persistent inhibition of FoxO1 with AS1842856 almost completely suppressed adipocyte differentiation, while selective inhibition in specific stages had differential effects on adipogenesis. Our data present a new view of FoxO1 in adipogenic regulation, and suggest AS1842856 can be an anti-obesity agent that warrants further investigation.

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The kinetics of FoxO1 activation followed a series of sigmoid curves during adipogenesis. (A) Western blots showing FoxO1 expression (i.e., tFoxO1), activation (i.e., dephosphorylation) and inactivation (i.e., phosphorylation) during adipogenesis. β-actin was probed as the loading control. (B) Densitometric analysis of protein gel blot images with NIH ImageJ software; n = 3−5. AP, activation peak; IP, inactivation peak. * P < 0 .05; and ***, P < 0 .0001.
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f0003: The kinetics of FoxO1 activation followed a series of sigmoid curves during adipogenesis. (A) Western blots showing FoxO1 expression (i.e., tFoxO1), activation (i.e., dephosphorylation) and inactivation (i.e., phosphorylation) during adipogenesis. β-actin was probed as the loading control. (B) Densitometric analysis of protein gel blot images with NIH ImageJ software; n = 3−5. AP, activation peak; IP, inactivation peak. * P < 0 .05; and ***, P < 0 .0001.

Mentions: FoxO1 can repress PPARγ expression and transrepress its transactivation,15-18 implying that silencing FoxO1 may stimulate PPARγ and promotes adipogenesis. However, persistent inhibition of FoxO1 (days 0-12) with AS1842856 markedly suppressed PPARγ and prevented adipogenesis, suggesting FoxO1 activation was indispensable for adipogenesis (Figs. 1-2; Fig. S1). In line with this, silencing FoxO1 in preadipocytes with siRNA severely prevents the cells from differentiation.14 To better understand the physiological role of FoxO1, we studied the kinetics of FoxO1 activation (i.e., dephosphorylation) and inactivation (i.e., phosphorylation) during 3T3L1 cell differentiation.5 As shown in Fig. 3A and B, FoxO1 activation followed a series of sigmoid curves, revealing 3 inactivation peaks (days 1, 5 and 9) and 3 activation peaks (days 3, 7 and 10). FoxO1 was most inactive on day 1 (IP1), when the cells reentered into cell cycle with clonal expansion (Fig. 3B).15 By contrast, FoxO1 reached the first activation peak (AP1) on day 3, when postmitotic growth arrest takes place (Fig. 3B).15 These data strongly support the notion that FoxO1 regulates the cell cycle.5,15Figure 3.


Targeting FoxO1 with AS1842856 suppresses adipogenesis.

Zou P, Liu L, Zheng L, Liu L, Stoneman RE, Cho A, Emery A, Gilbert ER, Cheng Z - Cell Cycle (2014)

The kinetics of FoxO1 activation followed a series of sigmoid curves during adipogenesis. (A) Western blots showing FoxO1 expression (i.e., tFoxO1), activation (i.e., dephosphorylation) and inactivation (i.e., phosphorylation) during adipogenesis. β-actin was probed as the loading control. (B) Densitometric analysis of protein gel blot images with NIH ImageJ software; n = 3−5. AP, activation peak; IP, inactivation peak. * P < 0 .05; and ***, P < 0 .0001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4613185&req=5

f0003: The kinetics of FoxO1 activation followed a series of sigmoid curves during adipogenesis. (A) Western blots showing FoxO1 expression (i.e., tFoxO1), activation (i.e., dephosphorylation) and inactivation (i.e., phosphorylation) during adipogenesis. β-actin was probed as the loading control. (B) Densitometric analysis of protein gel blot images with NIH ImageJ software; n = 3−5. AP, activation peak; IP, inactivation peak. * P < 0 .05; and ***, P < 0 .0001.
Mentions: FoxO1 can repress PPARγ expression and transrepress its transactivation,15-18 implying that silencing FoxO1 may stimulate PPARγ and promotes adipogenesis. However, persistent inhibition of FoxO1 (days 0-12) with AS1842856 markedly suppressed PPARγ and prevented adipogenesis, suggesting FoxO1 activation was indispensable for adipogenesis (Figs. 1-2; Fig. S1). In line with this, silencing FoxO1 in preadipocytes with siRNA severely prevents the cells from differentiation.14 To better understand the physiological role of FoxO1, we studied the kinetics of FoxO1 activation (i.e., dephosphorylation) and inactivation (i.e., phosphorylation) during 3T3L1 cell differentiation.5 As shown in Fig. 3A and B, FoxO1 activation followed a series of sigmoid curves, revealing 3 inactivation peaks (days 1, 5 and 9) and 3 activation peaks (days 3, 7 and 10). FoxO1 was most inactive on day 1 (IP1), when the cells reentered into cell cycle with clonal expansion (Fig. 3B).15 By contrast, FoxO1 reached the first activation peak (AP1) on day 3, when postmitotic growth arrest takes place (Fig. 3B).15 These data strongly support the notion that FoxO1 regulates the cell cycle.5,15Figure 3.

Bottom Line: As FoxO1 has been implicated in adipogenic regulation, we investigated the kinetics of FoxO1 activation during adipocyte differentiation, and tested the effects of FoxO1 antagonist (AS1842856) on adipogenesis.We found for the first time that the kinetics of FoxO1 activation follows a series of sigmoid curves, and reveals the phases relevant to clonal expansion, cell cycle arrest, and the regulation of PPARγ, adiponectin, and mitochondrial proteins (complexes I and III).Importantly, persistent inhibition of FoxO1 with AS1842856 almost completely suppressed adipocyte differentiation, while selective inhibition in specific stages had differential effects on adipogenesis.

View Article: PubMed Central - PubMed

Affiliation: a Department of Human Nutrition, Foods and Exercise; Fralin Life Science Institute; College of Agriculture and Life Science; Virginia Tech , Blacksburg , VA USA.

ABSTRACT
Hyperplasia (i.e., increased adipogenesis) contributes to excess adiposity, the hallmark of obesity that can trigger metabolic complications. As FoxO1 has been implicated in adipogenic regulation, we investigated the kinetics of FoxO1 activation during adipocyte differentiation, and tested the effects of FoxO1 antagonist (AS1842856) on adipogenesis. We found for the first time that the kinetics of FoxO1 activation follows a series of sigmoid curves, and reveals the phases relevant to clonal expansion, cell cycle arrest, and the regulation of PPARγ, adiponectin, and mitochondrial proteins (complexes I and III). In addition, multiple activation-inactivation transitions exist in the stage of terminal differentiation. Importantly, persistent inhibition of FoxO1 with AS1842856 almost completely suppressed adipocyte differentiation, while selective inhibition in specific stages had differential effects on adipogenesis. Our data present a new view of FoxO1 in adipogenic regulation, and suggest AS1842856 can be an anti-obesity agent that warrants further investigation.

Show MeSH
Related in: MedlinePlus