Author Correction: The kinase TBK1 controls IgA class switching by negatively regulating noncanonical NF-κB signaling.

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The kinase TBK1 controls IgA class switching by negatively regulating noncanonical NF-κB signaling.

Immunoglobulin class switching is crucial for the generation of antibody diversity in humoral immunity and, when deregulated, also has severe pathological consequences. How the magnitude of immunoglobulin isotype switching is controlled is still poorly understood. Here we identify the kinase TBK1 as a pivotal negative regulator of class switching to the immunoglobulin A (IgA) isotype. B cell-specific ablation of TBK1 in mice resulted in uncontrolled production of IgA and the development of nephropathy-like disease signs. TBK1 negatively regulated IgA class switching by attenuating noncanonical signaling via the transcription factor NF-κB, an action that involved TBK1-mediated phosphorylation and subsequent degradation of the NF-κB-inducing kinase NIK. Our findings establish TBK1 as a pivotal negative regulator of the noncanonical NF-κB pathway and identify a unique mechanism that controls IgA production.

Ubc13 maintains the suppressive function of regulatory T cells and prevents their conversion into effector-like T cells.

The maintenance of immune homeostasis requires regulatory T cells (Treg cells). Here we found that Treg cell­specific ablation of Ubc13, a Lys63 (K63)-specific ubiquitin-conjugating enzyme, caused aberrant T cell activation and autoimmunity. Although Ubc13 deficiency did not affect the survival of Treg cells or expression of the transcription factor Foxp3, it impaired the in vivo suppressive function of Treg cells and rendered them sensitive to the acquisition of T helper type 1 (TH1) cell­ and interleukin 17 (IL-17)-producing helper T (TH17) cell­like effector phenotypes. This function of Ubc13 involved its downstream target, the kinase IKK. The Ubc13-IKK signaling axis controlled the expression of specific Treg cell effector molecules, including IL-10 and SOCS1. Collectively, our findings suggest that the Ubc13-IKK signaling axis regulates the molecular program that maintains Treg cell function and prevents Treg cells from acquiring inflammatory phenotypes.

Modulation of NLRP3 inflammasomes activation contributes to improved survival and function of mesenchymal stromal cell spheroids.

Mesenchymal stem cells (MSCs) are ubiquitous multipotent cells that exhibit significant therapeutic potentials in a variety of disorders. Nevertheless, their clinical efficacy is limited owing to poor survival, low rate of engraftment, and impaired potency upon transplantation. Spheroidal three-dimensional (3D) culture of MSCs (MSC3D) has been proven to better preserve their in vivo functional properties. However, the molecular mechanisms underlying the improvement in MSC function by spheroid formation are not clearly understood. NLRP3 inflammasomes, a key component of the innate immune system, have recently been shown to play a role in cell fate decision of MSCs. The present study examined the role of NLRP3 inflammasomes in the survival and potency of MSC spheroids. We found that MSC3D led to decreased activation of NLRP3 inflammasomes through alleviation of ER stress in an autophagy-dependent manner. Importantly, downregulation of NLRP3 inflammasomes signaling critically contributes to the enhanced survival rate in MSC3D through modulation of pyroptosis and apoptosis. The critical role of NLRP3 inflammasome suppression in the enhanced therapeutic efficacy of MSC spheroids was further confirmed in an in vivo mouse model of DSS-induced colitis. These findings suggest that 3D culture confers survival and functional advantages to MSCs by suppressing NLRP3 inflammasome activation.

The ubiquitin ligase Peli1 negatively regulates T cell activation and prevents autoimmunity.

T cell activation is subject to tight regulation to avoid inappropriate responses to self antigens. Here we show that genetic deficiency in the ubiquitin ligase Peli1 caused hyperactivation of T cells and rendered T cells refractory to suppression by regulatory T cells and transforming growth factor-ß (TGF-ß). As a result, Peli1-deficient mice spontaneously developed autoimmunity characterized by multiorgan inflammation and autoantibody production. Peli1 deficiency resulted in the nuclear accumulation of c-Rel, a member of the NF-κB family of transcription factors with pivotal roles in T cell activation. Peli1 negatively regulated c-Rel by mediating its Lys48 (K48) ubiquitination. Our results identify Peli1 as a critical factor in the maintenance of peripheral T cell tolerance and demonstrate a previously unknown mechanism of c-Rel regulation.

Inflammatory T cell responses rely on amino acid transporter ASCT2 facilitation of glutamine uptake and mTORC1 kinase activation.

Glutamine has been implicated as an immunomodulatory nutrient, but how glutamine uptake is mediated during T cell activation is poorly understood. We have shown that naive T cell activation is coupled with rapid glutamine uptake, which depended on the amino acid transporter ASCT2. ASCT2 deficiency impaired the induction of T helper 1 (Th1) and Th17 cells and attenuated inflammatory T cell responses in mouse models of immunity and autoimmunity. Mechanistically, ASCT2 was required for T cell receptor (TCR)-stimulated activation of the metabolic kinase mTORC1. We have further shown that TCR-stimulated glutamine uptake and mTORC1 activation also required a TCR signaling complex composed of the scaffold protein CARMA1, the adaptor molecule BCL10, and the paracaspase MALT1. This function was independent of IKK kinase, a major downstream target of the CARMA1 complex. These findings highlight a mechanism of T cell activation involving ASCT2-dependent integration of the TCR signal and a metabolic signaling pathway.

Geranylgeranyl pyrophosphate amplifies Treg differentiation via increased IL-2 expression to ameliorate DSS-induced colitis.

Blocking the mevalonate pathway for cholesterol reduction by using statin may have adverse effects including statin-induced colitis. Moreover, one of the predisposing factors for colitis is an imbalanced CD4+ T cell, which can be observed on the complete deletion of HMG-CoA reductase (HMGCR), a target of statins. In this study, we inquired geranylgeranyl pyrophosphate (GGPP) is responsible for maintaining the T-cell homeostasis. Following dextran sulfate sodium (DSS)-induced colitis, simvastatin increased the severity of disease, while cotreatment with GGPP, but not with cholesterol, reversed the disease magnitude. GGPP ameliorated DSS-induced colitis by increasing Treg cells. GGPP amplified Treg differentiation through increased IL-2/STAT 5 signaling. GGPP prenylated Ras protein, a prerequisite for extracellular signal-regulated kinase (ERK) pathway activation, leading to increased IL-2 production. Higher simvastatin dose increased the severity of colitis. GGPP ameliorated simvastatin-increased colitis by increasing Treg cells. Treg cells, which have the capacity to suppress inflammatory T cells and were generated through IL-2/STAT5 signaling, increased IL-2 production through prenylation and activation of the Ras/ERK pathway.

AMPK Amplifies IL2-STAT5 Signaling to Maintain Stability of Regulatory T Cells in Aged Mice.

AMP-activated protein kinase (AMPK), an important regulator of the aging process, is expressed in various immune cells. However, its role in regulatory T cell (Treg) stability during aging is poorly understood. Here, we addressed the role of AMPK in Treg function and stability during aging by generating Treg-specific AMPKα1 knockout mice. In this study, we found that AMPKα1-deficient Tregs failed to control inflammation as effectively as normal Tregs did during aging. AMPK knockout from Tregs reduces STAT5 phosphorylation in response to interleukin (IL)-2 stimulation, thereby destabilizing Tregs by decreasing CD25 expression. Thus, our study addressed the role of AMPK in Tregs in sensing IL-2 signaling to amplify STAT5 phosphorylation, which, in turn, supports Treg stability by maintaining CD25 expression and controlling inflamm-aging.

AMPK promotes antitumor immunity by downregulating PD-1 in regulatory T cells via the HMGCR/p38 signaling pathway.

BACKGROUND: AMP-activated protein kinase (AMPK) is a metabolic sensor that maintains energy homeostasis. AMPK functions as a tumor suppressor in different cancers; however, its role in regulating antitumor immunity, particularly the function of regulatory T cells (Tregs), is poorly defined. METHODS: AMPKα1fl/flFoxp3YFP-Cre, Foxp3YFP-Cre, Rag1-/-, and C57BL/6 J mice were used for our research. Flow cytometry and cell sorting, western blotting, immuno-precipitation, immuno-fluorescence, glycolysis assay, and qRT-PCR were used to investigate the role of AMPK in suppressing programmed cell death 1 (PD-1) expression and for mechanistic investigation. RESULTS: The deletion of the AMPKα1 subunit in Tregs accelerates tumor growth by increasing the expression of PD-1. Metabolically, loss of AMPK in Tregs promotes glycolysis and the expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), a key enzyme of the mevalonate pathway. Mechanistically, AMPK activates the p38 mitogen-activated protein kinase (MAPK) that phosphorylates glycogen synthase kinase-3ß (GSK-3ß), inhibiting the expression of PD-1 in Tregs. CONCLUSION: Our study identified an AMPK regulatory mechanism of PD-1 expression via the HMGCR/p38 MAPK/GSK3ß signaling pathway. We propose that the AMPK activator can display synergic antitumor effect in murine tumor models, supporting their potential clinical use when combined with anti-PD-1 antibody, anti-CTLA-4 antibody, or a HMGCR inhibitor.

A common signaling pathway leading to degranulation in mast cells and its regulation by CCR1-ligand.

BACKGROUND: Signal transduction pathways mediated by various receptors expressed on mast cells are thought to be complex, and inhibitory signals that turn off activating signals are not known. METHODS: Upstream signaling cascades mediated by several known receptors in bone marrow-derived mast cells that lead to degranulation and mediator release were studied by immunoblotting and immunoprecipitation. Small interfering RNAs and knockout mice were used to confirm findings. RESULTS: All ligands tested including IgE/Ag, SCF, HSP70, CCL3, and its valiant eMIP induced phosphorylation of linker for activation of T cells (LAT), which triggered their receptor-mediated downstream signaling cascades that controlled degranulation and mediator release. Phosphorylation of lymphocyte-specific protein kinase (Lck) was induced by each ligand, which commonly played an indispensable role in LAT phosphorylation. In contrast, phosphorylation of spleen tyrosine kinase was additionally induced in cells stimulated only with IgE/Ag and SCF, which is also associated with LAT phosphorylation in part. Degranulation and mediator release induced by IgE/Ag, SCF, or HSP70 were enhanced by nanomolar doses of CCR1 ligands CCL3 and eMIP via enhanced LAT phosphorylation. On the other hand, micromolar doses of CCR1 ligand inhibited degranulation and mediator release from mast cells stimulated with IgE/Ag, SCF, or HSP70 by de-phosphorylation of phosphorylated Lck with Src homology region 2 domain-containing phosphatase-1. CONCLUSIONS: Linker for activation of T cells plays a central role in signal transduction pathways in mast cells stimulated with any ligand tested. Dose-dependent alternate costimulation and inhibition of CCR1 ligands in IgE/Ag-, SCF-, or HSP70-stimulated mast cells occur at the level of Lck-LAT phosphorylation.

N-Acetyldopamine derivatives from Periostracum Cicadae and their regulatory activities on Th1 and Th17 cell differentiation.

Bioassay-guided fractionation of a 90% ethanol extract of Periostracum Cicadae led to the isolation of two new N-acetyldopamine dimers (1a/1b) along with six known dimers (2a/2b, 3a/3b, and 4a/4b) and two monomers (5a/5b); compounds 2a/2b, 4a/4b and 5a/5b were newly isolated from this material. All compounds were isolated as enantiomeric mixtures and each enantiomer was successfully separated by chiral-phase HPLC. The structures including absolute configurations were confirmed by high-resolution electrospray ionization mass spectrometry (HR-ESIMS), 1D/2D nuclear magnetic resonance (NMR) spectroscopy, 1H iterative Full Spin Analysis (HiFSA), and electronic circular dichroism (ECD) spectroscopy. Subsequently, the bioactivities of these isolates were evaluated via CD4+ T cell differentiations, which are critical for immune responses and inflammation. The results revealed that compound 5b was observed to enhance the IFN-γ+ Th1 differentiation, which may have a potential for cancer immunotherapy.

A Study on the Effective Ratio of Fat to Stromal Vascular Fraction for Cell-Assisted Lipotransfer.

BACKGROUND: Fat grafting, used for soft tissue augmentation during aesthetic or reconstructive plastic surgery, has disadvantages of low efficiency and unpredictable resorption rate. As an alternative, cell-assisted lipotransfer (CAL) is widely used because of its simplicity and low fat resorption rate. However, relevant studies on optimal CAL parameters are still lacking. Here, we aimed to identify the most effective ratio of fat to stromal vascular fraction (SVF) for CAL. METHODS: We designed two experimental paradigms. The first involved four groups of mice, each group injected with varying ratios of fat and SVF purified from different amounts of fat from a fixed amount of harvested fat. The second experiment involved four groups of mice, each injected with varying amounts of SVF mixed with a fixed amount of fat tissue. The amount of surviving fat in both experiments was compared 8 weeks after fat transplantation. RESULTS: In the first experiment, the group injected with only fat, without consuming any of the harvested fat for SVF purification, showed the greatest mean volume and weight. In the second experiment, groups with 1:1 or more ratio of fat to SVF showed greater volume and weight than the group without SVF. Notably, a ratio of 1:1 did not give significantly different results than higher ratios. CONCLUSIONS: Thus, when a limited amount of fat tissue is available, using all of it for grafting is the most effective. However, if an adequate amount is available, using a fat-to-SVF ratio of 1:1 is the most efficient. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The orphan nuclear receptor NR4A1 promotes FcεRI-stimulated mast cell activation and anaphylaxis by counteracting the inhibitory LKB1/AMPK axis.

BACKGROUND: Nuclear receptor subfamily 4 group A member 1 (NR4A1), an orphan nuclear receptor, has been implicated in several biological events such as metabolism, apoptosis, and inflammation. Recent studies indicate a potential role for NR4A1 in mast cells, yet its role in allergic responses remains largely unknown. OBJECTIVES: The aim of this study was to clarify the role of NR4A1 in mast cell activation and anaphylaxis. METHODS: To evaluate the function of NR4A1 in mast cells, the impacts of siRNA knockdown, gene knockout, adenoviral overexpression, and pharmacological inhibition of NR4A1 on FcεRI signaling and effector functions in mouse bone marrow-derived mast cells (BMMCs) in vitro and on anaphylactic responses in vivo were evaluated. RESULTS: Knockdown or knockout of NR4A1 markedly suppressed degranulation and lipid mediator production by FcεRI-crosslinked BMMCs, while its overexpression augmented these responses. Treatment with a NR4A1 antagonist also blocked mast cell activation to a similar extent as NR4A1 knockdown or knockout. Moreover, mast cell-specific NR4A1-deficient mice displayed dampened anaphylactic responses in vivo. Mechanistically, NR4A1 promoted FcεRI signaling by counteracting the liver kinase B1 (LKB1)/adenosine monophosphate-activated protein kinase (AMPK) axis. Following FcεRI crosslinking, NR4A1 bound to the LKB1/AMPK complex and sequestered it in the nucleus, thereby promoting FcεRI downstream signaling pathways. Silencing or knockout of LKB1/AMPK largely abrogated the effect of NR4A1 on mast cell activation. Additionally, NR4A1 facilitated spleen tyrosine kinase activation independently of LKB1/AMPK. CONCLUSIONS: Nuclear receptor subfamily 4 group A member 1 positively regulates mast cell activation by antagonizing the LKB1-AMPK-dependent negative regulatory axis. This finding may provide a novel therapeutic strategy for the development of anti-allergic compounds.

OTUD7B controls non-canonical NF-κB activation through deubiquitination of TRAF3.

The non-canonical NF-κB pathway forms a major arm of NF-κB signalling that mediates important biological functions, including lymphoid organogenesis, B-lymphocyte function, and cell growth and survival. Activation of the non-canonical NF-κB pathway involves degradation of an inhibitory protein, TNF receptor-associated factor 3 (TRAF3), but how this signalling event is controlled is still unknown. Here we have identified the deubiquitinase OTUD7B as a pivotal regulator of the non-canonical NF-κB pathway. OTUD7B deficiency in mice has no appreciable effect on canonical NF-κB activation but causes hyperactivation of non-canonical NF-κB. In response to non-canonical NF-κB stimuli, OTUD7B binds and deubiquitinates TRAF3, thereby inhibiting TRAF3 proteolysis and preventing aberrant non-canonical NF-κB activation. Consequently, the OTUD7B deficiency results in B-cell hyper-responsiveness to antigens, lymphoid follicular hyperplasia in the intestinal mucosa, and elevated host-defence ability against an intestinal bacterial pathogen, Citrobacter rodentium. These findings establish OTUD7B as a crucial regulator of signal-induced non-canonical NF-κB activation and indicate a mechanism of immune regulation that involves OTUD7B-mediated deubiquitination and stabilization of TRAF3.

BJ-2266 ameliorates experimental autoimmune encephalomyelitis through down-regulation of the JAK/STAT signaling pathway.

CD4+ T cells differentiate into distinct effector subsets upon antigenic stimulation. Cytokines, and micro-environmental factors present during T-cell priming, direct differentiation of naïve CD4+ T cells into pro-inflammatory Th1 and Th17 cells. From extensive screening of 2,4,5-trimethylpyridin-3-ol derivatives with various functional groups at C(6)-position, BJ-2266, a 6-thioureido-derivative, showed potent inhibitory activity on in vitro T helper (Th)-cell differentiation. This compound inhibited IFN-γ and IL-17 production from polyclonal CD4+ T cells and ovalbumin (OVA)-specific CD4+ T cells that were activated by T-cell receptor (TCR) engagement. We assessed the inhibitory effect of BJ-2266 in experimental autoimmune encephalomyelitis (EAE). Our results suggest that BJ-2266 treatment significantly suppresses EAE disease progression with reduced generation of Th1 and Th17 cells. Notably, Th-cell differentiation was significantly suppressed by BJ-2266 treatment with no effect on apoptosis, activation and proliferation of activated T cells. Furthermore, adoptive transfer of BJ-2266 treated MOG-reactive Th1 and Th17 cells led to a lower EAE disease score and better clinical recovery from EAE. The underlying mechanism of BJ-2266 effect involved the inhibition of JAK/STAT phosphorylation that is critical for Th-cell differentiation. We conclude that BJ-2266 regulates the JAK/STAT pathway in response to cytokine signals and subsequently suppresses the differentiation of Th-cell responses.

Salinomycin ameliorates oxidative hepatic damage through AMP-activated protein kinase, facilitating autophagy.

Salinomycin, a monocarboxylic ionophore in Streptomyces albus, has been studied as an anti-cancer agent. However, we wondered whether salinomycin has another effect such as an anti-oxidant and hepatic protectant, because some chemical drugs treating human diseases were sometimes related with their toxic effects. Therefore, this study was conducted to examine the effects of salinomycin against oxidative stress and mitochondrial impairment in vivo and in vitro as well as the cellular mechanisms of action. In hepatocyte, salinomycin inhibited arachidonic acid (AA) + iron-induced apoptosis, mitochondrial dysfunction and ROS production. As a molecular mechanism, salinomycin induced autophagy through AMP-activated protein kinase (AMPK) activation, as assessed by the accumulation of acidic vesicle organelles, p62 and LC3-II. Moreover, these protective effects were blocked by AMPK inhibition, which indicates the importance of AMPK in the process of salinomycin's effects. In mice, oral administration of salinomycin protected against carbon tetrachloride (CCl4)-induced oxidative stress and liver injury, and also activated AMPK as well as autophagy-related proteins in the liver. Collectively, salinomycin had the ability to protect hepatocytes against AA+iron-induced reactive oxygen species production and mitochondrial dysfunction, as well as CCl4-induced liver injury. Although this beneficial effect was demonstrated under severe oxidative stress, this study showed that salinomycin protected the liver against the oxidative stress and liver damage through AMPK and autophagy, and suggest that salinomycin has a possibility to treat a broad range of diseases.

BJ-1108, a 6-Amino-2,4,5-trimethylpyridin-3-ol analogue, regulates differentiation of Th1 and Th17 cells to ameliorate experimental autoimmune encephalomyelitis.

BACKGROUND: CD4+ T cells play an important role in the initiation of an immune response by providing help to other cells. Among the helper T subsets, interferon-γ (IFN-γ)-secreting T helper 1 (Th1) and IL-17-secreting T helper 17 (Th17) cells are indispensable for clearance of intracellular as well as extracellular pathogens. However, Th1 and Th17 cells are also associated with pathogenesis and contribute to the progression of multiple inflammatory conditions and autoimmune diseases. RESULTS: In the current study, we found that BJ-1108, a 6-aminopyridin-3-ol analogue, significantly inhibited Th1 and Th17 differentiation in vitro in a concentration-dependent manner, with no effect on proliferation or apoptosis of activated T cells. Moreover, BJ-1108 inhibited differentiation of Th1 and Th17 cells in ovalbumin (OVA)-specific OT II mice. A complete Freund's adjuvant (CFA)/OVA-induced inflammatory model revealed that BJ-1108 can reduce generation of proinflammatory Th1 and Th17 cells. Furthermore, in vivo studies showed that BJ-1108 delayed onset of disease and suppressed experimental autoimmune encephalomyelitis (EAE) disease progression by inhibiting differentiation of Th1 and Th17 cells. CONCLUSIONS: BJ-1108 treatment ameliorates inflammation and EAE by inhibiting Th1 and Th17 cells differentiation. Our findings suggest that BJ-1108 is a promising novel therapeutic agent for the treatment of inflammation and autoimmune disease.

Globular Adiponectin Inhibits Lipopolysaccharide-Primed Inflammasomes Activation in Macrophages via Autophagy Induction: The Critical Role of AMPK Signaling.

The inflammasome acts as a key platform for the activation of pro-inflammatory cytokines. Adiponectin exhibits potent anti-inflammatory properties. However, the effect of adiponectin on the modulation of the inflammasome has not been explored. Herein, we show that globular adiponectin (gAcrp) suppressed lipopolysaccharide (LPS)-primed inflammasomes activation in murine peritoneal macrophages judged by prevention of interleukin-1ß (IL-1ß) maturation, caspase-1 activation, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) speck formation, and pyroptotic cell death. Interestingly, pretreatment with 3-methyl adenine, a pharmacological inhibitor of autophagy, abrogated the suppressive effects of gAcrp on IL-1ß secretion and caspase-1 activation, indicating the crucial role of autophagy induction in gAcrp-modulation of the inflammasome activation. In addition, inhibition of 5'Adenosine monophaspahate (AMP)-activated protein kinase (AMPK) signaling abolished suppressive effect of gAcrp on inflammasomes activation. Furthermore, autophagy induction or inhibition of the inflammasome activation by gAcrp was not observed in macrophages deficient in AMPK. Taken together, these results indicate that adiponectin inhibits LPS-primed inflammasomes activation in macrophages via autophagy induction and AMPK signaling-dependent mechanisms.

Critical Role of AMPK/FoxO3A Axis in Globular Adiponectin-Induced Cell Cycle Arrest and Apoptosis in Cancer Cells.

Adiponectin predominantly secreted from adipose tissue has exhibited potent anti-proliferative properties in cancer cells via modulating cell cycle and apoptosis. FoxO3A, a Forkhead box O member of the transcription factor, plays a critical role in modulating expression of genes involved in cell death and/or survival. In this study, we investigated the role of FoxO3A signaling in anti-cancer activities of adiponectin. Herein, we have shown that treatment with globular adiponectin (gAcrp) increases p27 but decreases cyclinD1 expression in human hepatoma (HepG2) and breast (MCF-7) cancer cells. Gene ablation of FoxO3A prevented gAcrp-induced increase in p27 and decreased in cyclin D1 expression, and further ameliorated cell cycle arrest by gAcrp, indicating a critical role of FoxO3A in gAcrp-induced cell cycle arrest of cancer cells. Moreover, treatment with gAcrp also induced caspase-3/7 activation and increased Fas ligand (FasL) expression in both HepG2 and MCF-7 cells. Transfection with FoxO3A siRNA inhibited gAcrp-induced caspase-3/7 activation and FasL expression, suggesting that FoxO3A signaling also plays an important role in gAcrp-induced apoptosis of cancer cells. We also found that gene silencing of AMPK prevented gAcrp-induced nuclear translocation of FoxO3A in HepG2 and MCF-7 cells. In addition, suppression of AMPK also blocked gAcrp-induced cell cycle arrest and further attenuated gAcrp-induced caspase-3/7 activation, indicating that AMPK signaling plays a pivotal role in both gAcrp-induced cell cycle arrest and apoptosis via acting as an upstream signaling of FoxO3A. Taken together, our findings demonstrated that AMPK/FoxO3A axis plays a cardinal role in anti-proliferative effect of adiponectin in cancer cells.