The AMPKyl subunit plays an essential role in erythrocyte membrane elasticity, and its genetic inactivation induces splenomegaly and anemia

Foretz, Marc; Hébrard, Sophie; Guihard, Soizic; Leclerc, Jocelyne; Cruzeiro, Marcio Do; Hamard, Ghislaine; Niedergang, Florence; Gaudry, Muriel; Viollet, Benoı̂t

doi:10.1096/fj.10-169383

Cited by 34 publications

(35 citation statements)

References 37 publications

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“…This can be explained by the importance of heterotrimeric complex in the stabilization of individual AMPK subunit. AMPK is stable as a heterotrimer complex, whereas each of its subunits is subject to an increased turnover rate and is depleted from the cell when not associated with others (41)(42)(43). Therefore, the observed higher expression of AMPK␤1 in AMPK␣ Ϫ/Ϫ MEFs indicates that the transduction of the Ad-DN resulted in an increase in the AMPK heterotrimer complex in the cell.…”

Section: Discussionmentioning

confidence: 99%

AMP-activated Protein Kinase Suppresses Matrix Metalloproteinase-9 Expression in Mouse Embryonic Fibroblasts

Morizane

Thanos

Takeuchi

et al. 2011

Journal of Biological Chemistry

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Matrix metalloproteinase-9 (MMP-9) plays a critical role in tissue remodeling under both physiological and pathological conditions. Although MMP-9 expression is low in most cells and is tightly controlled, the mechanism of its regulation is poorly understood. We utilized mouse embryonic fibroblasts (MEFs) that were nullizygous for the catalytic ␣ subunit of AMP-activated protein kinase (AMPK), which is a key regulator of energy homeostasis, to identify AMPK as a suppressor of MMP-9 expression. Total AMPK␣ deletion significantly elevated MMP-9 expression compared with wild-type (WT) MEFs, whereas single knock-out of the isoforms AMPK␣1 and AMPK␣2 caused minimal change in the level of MMP-9 expression. The suppressive role of AMPK on MMP-9 expression was mediated through both its activity and presence. Matrix metalloproteinase-9 (MMP-9, 2 gelatinase B) degrades denatured collagens and native collagen type IV, which is a major component of the extracellular matrix (ECM) and basement membranes (1). Under normal circumstances, the degradation of the ECM by MMP-9 is a tightly controlled process involved in physiological wound healing and embryo development (1, 2). Conversely, aberrant degradation of ECM by excess MMP-9 expression results in the pathologic destruction of connective tissue seen in cancer, arterial sclerosis, and rheumatoid arthritis (1, 3). Therefore, under physiological conditions, regulated MMP-9 expression is low (1), but the mechanisms behind this are obscure.AMP-activated protein kinase (AMPK) is a serine/threonine kinase, which regulates energy homeostasis and metabolic stress (4). AMPK acts as a sensor of cellular energy status and maintains the balance between ATP production and consumption. In mammals, AMPK exists as a heterotrimer with ␣, ␤, and ␥ subunits, each of which is encoded by two or three genes (␣1, ␣2, ␤1, ␤2, ␥1, ␥2, and ␥3). The ␣ subunit possesses catalytic activity, whereas the ␤ and ␥ subunits are regulatory and maintain the stability of the heterotrimer complex. The importance of AMPK␣ is illustrated by the fact that dual deficiency of AMPK␣1 and AMPK␣2 is embryonic lethal (5).Recent evidence suggests that AMPK has a much wider range of functions, including the regulation of cell growth, cell proliferation, cell polarity, and autophagy (6, 7). Because these functions are closely linked to the pathology of MMP-9-related diseases, including cancer, arterial sclerosis, and rheumatoid arthritis, we hypothesized that AMPK regulates MMP-9 expression. To address this, in the present study, we utilized AMPK␣-deficient mouse embryonic fibroblasts (MEFs) to investigate the effect of the genetic deletion and activation of AMPK on MMP-9 expression. EXPERIMENTAL PROCEDURESAntibodies, Recombinant Proteins, and Reagents-All antibodies, except for MMP-9 (Abcam, Cambridge, MA) and AMPK␣2 (Santa Cruz Biotechnology, Santa Cruz, CA), were purchased from Cell Signaling (Beverly, MA). Recombinant mouse TNF-␣, MMP-9, and MMP-2 proteins were obtained from R&D Systems (

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Section: Discussionmentioning

confidence: 99%

AMP-activated Protein Kinase Suppresses Matrix Metalloproteinase-9 Expression in Mouse Embryonic Fibroblasts

Morizane

Thanos

Takeuchi

et al. 2011

Journal of Biological Chemistry

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“…75-886) in accordance with European guidelines. The generation of AMPKγ1 −/− mice has been previously described (10). Global AMPKγ2 −/− mice were generated by deleting the entire exon 7 of the gene encoding AMPKγ2 in R299Q knockin mice using Sox2cre-driven excision (48).…”

Section: Methodsmentioning

confidence: 99%

Benzimidazole derivative small-molecule 991 enhances AMPK activity and glucose uptake induced by AICAR or contraction in skeletal muscle

Bultot

Jensen

Lai

et al. 2016

American Journal of Physiology-Endocrinology and Metabolism

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AMP-activated protein kinase (AMPK) plays diverse roles and coordinates complex metabolic pathways for maintenance of energy homeostasis. This could be explained by the fact that AMPK exists as multiple heterotrimer complexes comprising a catalytic α-subunit (α1 and α2) and regulatory β (β1 and β2)- and γ (γ1, γ2, γ3)-subunits, which are uniquely distributed across different cell types. There has been keen interest in developing specific and isoform-selective AMPK-activating drugs for therapeutic use and also as research tools. Moreover, establishing ways of enhancing cellular AMPK activity would be beneficial for both purposes. Here, we investigated if a recently described potent AMPK activator called 991, in combination with the commonly used activator 5-aminoimidazole-4-carboxamide riboside or contraction, further enhances AMPK activity and glucose transport in mouse skeletal muscle ex vivo. Given that the γ3-subunit is exclusively expressed in skeletal muscle and has been implicated in contraction-induced glucose transport, we measured the activity of AMPKγ3 as well as ubiquitously expressed γ1-containing complexes. We initially validated the specificity of the antibodies for the assessment of isoform-specific AMPK activity using AMPK-deficient mouse models. We observed that a low dose of 991 (5 μM) stimulated a modest or negligible activity of both γ1- and γ3-containing AMPK complexes. Strikingly, dual treatment with 991 and 5-aminoimidazole-4-carboxamide riboside or 991 and contraction profoundly enhanced AMPKγ1/γ3 complex activation and glucose transport compared with any of the single treatments. The study demonstrates the utility of a dual activator approach to achieve a greater activation of AMPK and downstream physiological responses in various cell types, including skeletal muscle.

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“…Interestingly, AMPK can regulate mitochondrial cardiolipin content (40), and this lipid is known to regulate bacterial HAS (39). As cardiolipin is typically in the mitochondria, this issue could be not critical for eukaryotic HASs, although very recently, it was reported that the AMPK ␥1 subunit can control erythrocyte membrane elasticity (41). Therefore, AMPK could modify membrane lipid composition indirectly by modulating HAS activity or stability.…”

Section: Ha Does Not Influence Ampk-mediated Reduction Of Cellmentioning

confidence: 99%

Hyaluronan Synthesis Is Inhibited by Adenosine Monophosphate-activated Protein Kinase through the Regulation of HAS2 Activity in Human Aortic Smooth Muscle Cells

Vigetti

Clerici

Deleonibus

et al. 2011

Journal of Biological Chemistry

106

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Hyaluronan (HA) is an extracellular matrix glycosaminoglycan (GAG) involved in cell motility, proliferation, tissue remodeling, development, differentiation, inflammation, tumor progression, and invasion and controls vessel thickening in cardiovascular diseases. Therefore, the control of HA synthesis could permit the finetuning of cell behavior, but the mechanisms that regulate HA synthesis are largely unknown. Recent studies suggest that the availability of the nucleotide-sugar precursors has a critical role. Because the formation of UDP-sugars is a highly energetically demanding process, we have analyzed whether the energy status of the cell could control GAG production. AMP-activated protein kinase (AMPK) is the main ATP/AMP sensor of mammalian cells, and we mimicked an energy stress by treating human aortic smooth muscle cells (AoSMCs) with the AMPK activators 5-aminoimidazole-4-carboxamide-1-␤-D-ribofuranoside and metformin. Under these conditions, HA synthesis, but not that of the other GAGs, was greatly reduced. We confirmed the inhibitory effect of AMPK using a specific inhibitor and knock-out cell lines. We found that AMPK phosphorylated Thr-110 of human HAS2, which inhibits its enzymatic activity. In contrast, the other two HAS isoenzymes (HAS1 and HAS3) were not modified by the kinase. The reduction of HA decreased the ability of AoSMCs to proliferate, migrate, and recruit immune cells, thereby reducing the pro-atherosclerotic AoSMC phenotype. Interestingly, such effects were not recovered by treatment with exogenous HA, suggesting that AMPK can block the pro-atherosclerotic signals driven by HA by interaction with its receptors.

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The AMPKyl subunit plays an essential role in erythrocyte membrane elasticity, and its genetic inactivation induces splenomegaly and anemia

Cited by 34 publications

References 37 publications

AMP-activated Protein Kinase Suppresses Matrix Metalloproteinase-9 Expression in Mouse Embryonic Fibroblasts

AMP-activated Protein Kinase Suppresses Matrix Metalloproteinase-9 Expression in Mouse Embryonic Fibroblasts

Benzimidazole derivative small-molecule 991 enhances AMPK activity and glucose uptake induced by AICAR or contraction in skeletal muscle

Hyaluronan Synthesis Is Inhibited by Adenosine Monophosphate-activated Protein Kinase through the Regulation of HAS2 Activity in Human Aortic Smooth Muscle Cells

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