Regulation of pyruvate carboxylase in 3T3-L1 cells

Zhang, Juan; Xia, Wenle; Ahmad, Feroz

doi:10.1042/bj3060205

Cited by 20 publications

(20 citation statements)

References 33 publications

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“…Therefore, the rate of incorporation of this isotope is correlated to the PCx activity. We observed an increase in PCx activity in adipocytes when compared with preadipocytes, a result that is in accord with a previous study (87). Furthermore, we showed that the PCx activity seems to be decreased by 40% in adipocytes treated for 6 days with 0.5 M FCCP when compared with untreated adipocytes, which is in accord with our results showing a decrease in the PCx protein content in these cells (Fig.…”

Section: Resultssupporting

confidence: 83%

“…The PCx downregulation observed for both transcript and protein abundance in adipocytes treated with FCCP has also been confirmed by measuring the activity of this enzyme. To determine the PCx activity, we modified slightly the protocol described by Atkin et al (4) and Zhang et al (87), as detailed in MATERIALS AND METHODS. The principle of the assay relies on the incorporation of 14 CO 2 provided as NaHCO 3 in solution during the transformation of pyruvate into oxaloacetate catalyzed by PCx.…”

Section: Resultsmentioning

confidence: 99%

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Mild mitochondrial uncoupling does not affect mitochondrial biogenesis but downregulates pyruvate carboxylase in adipocytes: role for triglyceride content reduction

Pauw

Demine

Tejerina

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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De Pauw A, Demine S, Tejerina S, Dieu M, Delaive E, Kel A, Renard P, Raes M, Arnould T. Mild mitochondrial uncoupling does not affect mitochondrial biogenesis but downregulates pyruvate carboxylase in adipocytes: role for triglyceride content reduction. Am J Physiol Endocrinol Metab 302: E1123-E1141, 2012. First published February 21, 2012 doi:10.1152/ajpendo.00117.2011In adipocytes, mitochondrial uncoupling is known to trigger a triglyceride loss comparable with the one induced by TNF␣, a proinflammatory cytokine. However, the impact of a mitochondrial uncoupling on the abundance/composition of mitochondria and its connection with triglyceride content in adipocytes is largely unknown. In this work, the effects of a mild mitochondrial uncoupling triggered by FCCP were investigated on the mitochondrial population of 3T3-L1 adipocytes by both quantitative and qualitative approaches. We found that mild mitochondrial uncoupling does not stimulate mitochondrial biogenesis in adipocytes but induces an adaptive cell response characterized by quantitative modifications of mitochondrial protein content. Superoxide anion radical level was increased in mitochondria of both TNF␣-and FCCP-treated adipocytes, whereas mitochondrial DNA copy number was significantly higher only in TNF␣-treated cells. Subproteomic analysis revealed that the abundance of pyruvate carboxylase was reduced significantly in mitochondria of TNF␣-and FCCP-treated adipocytes. Functional study showed that overexpression of this major enzyme of lipid metabolism is able to prevent the triglyceride content reduction in adipocytes exposed to mitochondrial uncoupling or TNF␣. These results suggest a new mechanism by which the effects of mitochondrial uncoupling might limit triglyceride accumulation in adipocytes.adipocytes; carbonyl cyanide p-trifluoromethoxyphenylhydrazone; tumor necrosis factor-␣; mitoproteome OBESITY RESULTS LARGELY FROM A CHRONICALLY POSITIVE energy balance. Therefore, reducing body energy intake and increasing energy expenditure are two approaches that have been translated into strategies to limit fat accumulation. Because mitochondria play a critical role in the process of energy expenditure, the alteration of oxidative phosphorylation (OX-PHOS) efficiency through OXPHOS uncoupling from ATP production in white adipocytes has been considered as an attractive approach to fight obesity (7, 69). In other words, uncoupling increases cellular metabolic demand since uncoupling OXPHOS lowers ATP production and increases the demand for reducing equivalents to restore/maintain mitochondrial membrane potential, thereby increasing substrate catabolism, which would theoretically decrease triglyceride (TG) stores in adipocytes. Indeed, although mitochondrial dysfunction could represent a major cause of lipid metabolism disorders and pathological triglyceride accumulation in several cell lines (50, 75), we and others have shown that mitochondrial uncoupling in adipocytes triggers lipolysis, limits fatty acid synthesis, and leads to a reduction in TG ...

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Mild mitochondrial uncoupling does not affect mitochondrial biogenesis but downregulates pyruvate carboxylase in adipocytes: role for triglyceride content reduction

Pauw

Demine

Tejerina

et al. 2012

American Journal of Physiology-Endocrinology and Metabolism

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“…S1, different genes involved in osteogenic differentiation are upregulated in ATP-treated BM-hMSCs compared to the untreated sample, such as osteoblastic transcription factors (ie, RUNX2 [38] and FOXO1 [39]), osteoblastic markers (ie, ANKH, BGLAP, and SPP1 [40,41]), and osteogenic growth factors (ie, BMP2, BMP6, WISP2, and IGFBP5 [42][43][44][45]). Moreover, ATP treatment of BM-hMSCs increased the expression of adipogenic transcription factors (ie, CEBPA, PPARGC1A, and CEBPB) [46] and adipocytespecific proteins (ie, ADFP, PC, and SPG20 [47][48][49]) (Supplementary Fig. S1).…”

Section: Gene Expression Profile Of Atp-treated Undifferentiated Bm-hmentioning

confidence: 99%

Extracellular Purines Promote the Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells to the Osteogenic and Adipogenic Lineages

Ciciarello

Zini

Rossi

et al. 2013

Stem Cells and Development

101

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Extracellular nucleotides are potent signaling molecules mediating cell-specific biological functions, mostly within the processes of tissue damage and repair and flogosis. We previously demonstrated that adenosine 5¢-triphosphate (ATP) inhibits the proliferation of human bone marrow-derived mesenchymal stem cells (BMhMSCs), while stimulating, in vitro and in vivo, their migration. Here, we investigated the effects of ATP on BM-hMSC differentiation capacity. Molecular analysis showed that ATP treatment modulated the expression of several genes governing adipogenic and osteoblastic (ie, WNT-pathway-related genes) differentiation of MSCs. Functional studies demonstrated that ATP, under specific culture conditions, stimulated adipogenesis by significantly increasing the lipid accumulation and the expression levels of the adipogenic master gene PPARc (peroxisome proliferator-activated receptor-gamma). In addition, ATP stimulated osteogenic differentiation by promoting mineralization and expression of the osteoblast-related gene RUNX2 (runt-related transcription factor 2). Furthermore, we demonstrated that ATP stimulated adipogenesis via its triphosphate form, while osteogenic differentiation was induced by the nucleoside adenosine, resulting from ATP degradation induced by CD39 and CD73 ectonucleotidases expressed on the MSC membrane. The pharmacological profile of P2 purinergic receptors (P2Rs) suggests that adipogenic differentiation is mainly mediated by the engagement of P2Y1 and P2Y4 receptors, while stimulation of the P1R adenosine-specific subtype A2B is involved in adenosine-induced osteogenic differentiation. Thus, we provide new insights into molecular regulation of MSC differentiation.

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“…These two types of mechanism permit an increase in the rate of gluconeogenesis during starvation and diabetes, in periods of enhanced cellular metabolism induced by thyroid hormone, in neonatal development and permit an increase in the rate of lipogenesis in differentiating adipocytes (4). It has been shown that regulation of PC gene expression during the differentiation of 3T3-L1 mouse fibroblasts to adipocytes may be exerted at a pretranslational level (5,6). However, little is known about the mechanism of hormonal regulation of PC expression at the molecular level.…”

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confidence: 99%