LPS Stimulation Induces Small Heterodimer Partner Expression Through the AMPK-NRF2 Pathway in Large Yellow Croaker (Larimichthys crocea).

The mall heterodimer partner (SHP) plays an important regulatory role in mammal inflammation. The main objective of this study was to investigate the response of SHP to inflammatory stimulation and its underlying mechanism. The shp gene from large yellow croakers, was cloned, and this gene is mainly expressed in the liver and intestine. Lipopolysaccharide (LPS) stimulation induced the mRNA expression and protein level of SHP in macrophages of large yellow croakers. Overexpression of SHP significantly decreased mRNA expression of tnfα, il-1ß, il-6 and cox2 induced by LPS treatment in macrophages. LPS stimulation increased the phosphorylation level of Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) in macrophages. AMPK inhibitor treatment significantly decreased the expression of SHP induced by LPS while AMPK activator significantly increased the expression of SHP. The nuclear factor-erythroid 2-related factor 2 (NRF2) increased the promoter activity of SHP in large yellow croakers and the level of nuclear NRF2 was increased by LPS stimulation and AMPK activation. NRF2 inhibitor treatment significantly decreased mRNA expression of shp induced by LPS and AMPK activator. In conclusion, LPS can induce SHP expression by activating the AMPK-NRF2 pathway while SHP could negatively regulate LPS-induced inflammation in large yellow croakers. This study may be benefit to the development of immunology of marine fish and provide new ideas for inflammation-related diseases.

Adenylate Kinase 4 Promotes Inflammatory Gene Expression via Hif1α and AMPK in Macrophages.

Macrophages comprise the front line of defense against various pathogens. Classically activated macrophages (M1), induced by IFN-γ and LPS, highly express inflammatory cytokines and contribute to inflammatory processes. By contrast, alternatively activated macrophages (M2) are induced by IL-4 and IL-13, produce IL-10, and display anti-inflammatory activity. Adenylate kinase 4 (Ak4), an enzyme that transfers phosphate group among ATP/GTP, AMP, and ADP, is a key modulator of ATP and maintains the homeostasis of cellular nucleotides which is essential for cell functions. However, its role in regulating the function of macrophages is not fully understood. Here we report that Ak4 expression is induced in M1 but not M2 macrophages. Suppressing the expression of Ak4 in M1 macrophages with shRNA or siRNA enhances ATP production and decreases ROS production, bactericidal ability and glycolysis in M1 cells. Moreover, Ak4 regulates the expression of inflammation genes, including Il1b, Il6, Tnfa, Nos2, Nox2, and Hif1a, in M1 macrophages. We further demonstrate that Ak4 inhibits the activation of AMPK and forms a positive feedback loop with Hif1α to promote the expression of inflammation-related genes in M1 cells. Furthermore, RNA-seq analysis demonstrates that Ak4 also regulates other biological processes in addition to the expression of inflammation-related genes in M1 cells. Interestingly, Ak4 does not regulate M1/M2 polarization. Taken together, our study uncovers a potential mechanism linking energy consumption and inflammation in macrophages.

A-769662 inhibits adipocyte glucose uptake in an AMPK-independent manner.

Activation of AMP-activated protein kinase (AMPK) is considered a valid strategy for the treatment of type 2 diabetes. However, despite the importance of adipose tissue for whole-body energy homeostasis, the effect of AMPK activation in adipocytes has only been studied to a limited extent and mainly with the AMP-mimetic 5-aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside (AICAR), which has limited specificity. The aim of this study was to evaluate the effect of the allosteric AMPK activators A-769662 and 991 on glucose uptake in adipocytes. For this purpose, primary rat or human adipocytes, and cultured 3T3-L1 adipocytes, were treated with either of the allosteric activators, or AICAR, and basal and insulin-stimulated glucose uptake was assessed. Additionally, the effect of AMPK activators on insulin-stimulated phosphorylation of Akt and Akt substrate of 160 kDa was assessed. Furthermore, primary adipocytes from ADaM site binding drug-resistant AMPKß1 S108A knock-in mice were employed to investigate the specificity of the drugs for the observed effects. Our results show that insulin-stimulated adipocyte glucose uptake was significantly reduced by A-769662 but not 991, yet neither activator had any clear effects on basal or insulin-stimulated Akt/AS160 signaling. The use of AMPKß1 S108A mutant-expressing adipocytes revealed that the observed inhibition of glucose uptake by A-769662 is most likely AMPK-independent, a finding which is supported by the rapid inhibitory effect A-769662 exerts on glucose uptake in 3T3-L1 adipocytes. These data suggest that AMPK activation per se does not inhibit glucose uptake in adipocytes and that the effects of AICAR and A-769662 are AMPK-independent.

The MAPK and AMPK signalings: interplay and implication in targeted cancer therapy.

Cancer is characterized as a complex disease caused by coordinated alterations of multiple signaling pathways. The Ras/RAF/MEK/ERK (MAPK) signaling is one of the best-defined pathways in cancer biology, and its hyperactivation is responsible for over 40% human cancer cases. To drive carcinogenesis, this signaling promotes cellular overgrowth by turning on proliferative genes, and simultaneously enables cells to overcome metabolic stress by inhibiting AMPK signaling, a key singular node of cellular metabolism. Recent studies have shown that AMPK signaling can also reversibly regulate hyperactive MAPK signaling in cancer cells by phosphorylating its key components, RAF/KSR family kinases, which affects not only carcinogenesis but also the outcomes of targeted cancer therapies against the MAPK signaling. In this review, we will summarize the current proceedings of how MAPK-AMPK signalings interplay with each other in cancer biology, as well as its implications in clinic cancer treatment with MAPK inhibition and AMPK modulators, and discuss the exploitation of combinatory therapies targeting both MAPK and AMPK as a novel therapeutic intervention.

Attenuation of Free Fatty Acid (FFA)-Induced Skeletal Muscle Cell Insulin Resistance by Resveratrol is Linked to Activation of AMPK and Inhibition of mTOR and p70 S6K.

Insulin resistance, a main characteristic of type 2 diabetes mellitus (T2DM), is linked to obesity and excessive levels of plasma free fatty acids (FFA). Studies indicated that significantly elevated levels of FFAs lead to skeletal muscle insulin resistance, by dysregulating the steps in the insulin signaling cascade. The polyphenol resveratrol (RSV) was shown to have antidiabetic properties but the exact mechanism(s) involved are not clearly understood. In the present study, we examined the effect of RSV on FFA-induced insulin resistance in skeletal muscle cells in vitro and investigated the mechanisms involved. Parental and GLUT4myc-overexpressing L6 rat skeletal myotubes were used. [3H]2-deoxyglucose (2DG) uptake was measured, and total and phosphorylated levels of specific proteins were examined by immunoblotting. Exposure of L6 cells to FFA palmitate decreased the insulin-stimulated glucose uptake, indicating insulin resistance. Palmitate increased ser307 (131% ± 1.84% of control, p < 0.001) and ser636/639 (148% ± 10.1% of control, p < 0.01) phosphorylation of IRS-1, and increased the phosphorylation levels of mTOR (174% ± 15.4% of control, p < 0.01) and p70 S6K (162% ± 20.2% of control, p < 0.05). Treatment with RSV completely abolished these palmitate-induced responses. In addition, RSV increased the activation of AMPK and restored the insulin-mediated increase in (a) plasma membrane GLUT4 glucose transporter levels and (b) glucose uptake. These data suggest that RSV has the potential to counteract the FFA-induced muscle insulin resistance.

Cellular damage, including wounding, drives C. elegans stress-induced sleep.

Across animal phyla, sleep is associated with increased cellular repair, suggesting that cellular damage may be a core component of sleep pressure. In support of this notion, sleep in the nematode Caenorhabditis elegans can be triggered by damaging conditions, including noxious heat, high salt, and ultraviolet light exposure. It is not clear, however, whether this stress-induced sleep (SIS) is a direct consequence of cellular damage, or of a resulting energy deficit, or whether it is triggered simply by the sensation of noxious conditions. Here, we show that thermosensation is dispensable for heat-induced sleep, that osmosensation is dispensable for salt-induced sleep, and that wounding is also a sleep trigger, together indicating that SIS is not triggered by sensation of noxious environments. We present evidence that genetic variation in cellular repair pathways impacts sleep amount, and that SIS involves systemic monitoring of cellular damage. We show that the low-energy sensor AMP-activated protein kinase (AMPK) is not required for SIS, suggesting that energy deficit is not the primary sleep trigger. Instead, AMPK-deficient animals display enhanced SIS responses, and pharmacological activation of AMPK reduces SIS, suggesting that ATP-dependent repair of cellular damage mitigates sleep pressure.

Interleukin-6 Treatment Results in GLUT4 Translocation and AMPK Phosphorylation in Neuronal SH-SY5Y Cells.

Interleukin-6 (IL-6) is a pleiotropic cytokine that can be released from the brain during prolonged exercise. In peripheral tissues, exercise induced IL-6 can result in GLUT4 translocation and increased glucose uptake through AMPK activation. GLUT4 is expressed in the brain and can be recruited to axonal plasma membranes with neuronal activity through AMPK activation. The aim of this study is to examine if IL-6 treatment: (1) results in AMPK activation in neuronal cells, (2) increases the activation of proteins involved in GLUT4 translocation, and (3) increases neuronal glucose uptake. Retinoic acid was used to differentiate SH-SY5Y neuronal cells. Treatment with 100 nM of insulin increased the phosphorylation of Akt and AS160 (p < 0.05). Treatment with 20 ng/mL of IL-6 resulted in the phosphorylation of STAT3 at Tyr705 (p ≤ 0.05) as well as AS160 (p < 0.05). Fluorescent Glut4GFP imaging revealed treatment with 20ng/mL of IL-6 resulted in a significant mobilization towards the plasma membrane after 5 min until 30 min. There was no difference in GLUT4 mobilization between the insulin and IL-6 treated groups. Importantly, IL-6 treatment increased glucose uptake. Our findings demonstrate that IL-6 and insulin can phosphorylate AS160 via different signaling pathways (AMPK and PI3K/Akt, respectively) and promote GLUT4 translocation towards the neuronal plasma membrane, resulting in increased neuronal glucose uptake in SH-SY5Y cells.

Role of Impaired Nutrient and Oxygen Deprivation Signaling and Deficient Autophagic Flux in Diabetic CKD Development: Implications for Understanding the Effects of Sodium-Glucose Cotransporter 2-Inhibitors.

Growing evidence indicates that oxidative and endoplasmic reticular stress, which trigger changes in ion channels and inflammatory pathways that may undermine cellular homeostasis and survival, are critical determinants of injury in the diabetic kidney. Cells are normally able to mitigate these cellular stresses by maintaining high levels of autophagy, an intracellular lysosome-dependent degradative pathway that clears the cytoplasm of dysfunctional organelles. However, the capacity for autophagy in both podocytes and renal tubular cells is markedly impaired in type 2 diabetes, and this deficiency contributes importantly to the intensity of renal injury. The primary drivers of autophagy in states of nutrient and oxygen deprivation-sirtuin-1 (SIRT1), AMP-activated protein kinase (AMPK), and hypoxia-inducible factors (HIF-1α and HIF-2α)-can exert renoprotective effects by promoting autophagic flux and by exerting direct effects on sodium transport and inflammasome activation. Type 2 diabetes is characterized by marked suppression of SIRT1 and AMPK, leading to a diminution in autophagic flux in glomerular podocytes and renal tubules and markedly increasing their susceptibility to renal injury. Importantly, because insulin acts to depress autophagic flux, these derangements in nutrient deprivation signaling are not ameliorated by antihyperglycemic drugs that enhance insulin secretion or signaling. Metformin is an established AMPK agonist that can promote autophagy, but its effects on the course of CKD have been demonstrated only in the experimental setting. In contrast, the effects of sodium-glucose cotransporter-2 (SGLT2) inhibitors may be related primarily to enhanced SIRT1 and HIF-2α signaling; this can explain the effects of SGLT2 inhibitors to promote ketonemia and erythrocytosis and potentially underlies their actions to increase autophagy and mute inflammation in the diabetic kidney. These distinctions may contribute importantly to the consistent benefit of SGLT2 inhibitors to slow the deterioration in glomerular function and reduce the risk of ESKD in large-scale randomized clinical trials of patients with type 2 diabetes.

Role of adenylate kinase 1 in the integument development of Schistosoma japonicum schistosomula.

Schistosomula antigens play an important role in the growth and development of Schistosoma japonicum. We investigated the role of S. japonicum adenylate kinase 1 (SjAK1) in the growth and development of schistosomula. Quantitative real-time PCR showed that SjAK1 mRNA was expressed in all schistosomula stages, but increased gradually with the development of S. japonicum schistosomula. Using immunohistochemical techniques, the AK1 protein was found to be mainly distributed in the tegument and in some parenchymal tissues of the schistosomula. Double-stranded RNA-mediated knockdown of AK1 reduced AK1 mRNA transcripts by more than 90%; western blot analysis demonstrated that AK1 protein expression decreased by 66%. Scanning electron microscopy following RNA-mediated AK1 knockdown demonstrated that the sensory papillae degenerated significantly. Transmission electron microscopy demonstrated that the mean thickness of the tegument in the SjAK1 interference group was lower than that in the negative control group. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) suggested that, compared with the negative control group, apoptosis increased in the interference group. These results show that AK1 may be involved in the growth and development of S. japonicum schistosomula, and thus may be a target when developing treatments for schistosomiasis.

The Role of Autophagy in Cancer Radiotherapy.

BACKGROUND: Autophagy, a pathway for lysosomal-mediated cellular degradation, is a catabolic process that recycles intracellular components to maintain metabolism and survival. It is classified into three major types: macroautophagy, microautophagy, and the chaperone-mediated autophagy (CMA). Autophagy is a dynamic and multistep process that includes four stages: nucleation, elongation, autophagosome formation, and fusion. Interestingly, the influence of autophagy in cancer development is complex and paradoxical, suppressive, or promotive in different contexts. Autophagy in cancer has been demonstrated to serve as both a tumour suppressor and promoter. Radiotherapy is a powerful and common strategy for many different types of cancer and can induce autophagy, which has been shown to modulate sensitivity of cancer to radiotherapy. However, the role of autophagy in radiation treatment is controversial. Some reports showed that the upregulation of autophagy was cytoprotective for cancer cells. Others, in contrast, showed that the induction of autophagy was advantageous. Here, we reviewed recent studies and attempted to discuss the various aspects of autophagy in response to radiotherapy of cancer. Thus, we could decrease the viability of cancer cell and increase the sensibility of cancer cells to radiation, providing a new basis for the application of autophagy in clinical tumor radiotherapy.

hCINAP regulates the DNA-damage response and mediates the resistance of acute myelocytic leukemia cells to therapy.

Acute myeloid leukemia (AML) is a genetically heterogeneous malignant disorder of the hematopoietic system, characterized by the accumulation of DNA-damaged immature myeloid precursors. Here, we find that hCINAP is involved in the repair of double-stranded DNA breaks (DSB) and that its expression correlates with AML prognosis. Following DSB, hCINAP is recruited to damage sites where it promotes SENP3-dependent deSUMOylation of NPM1. This in turn results in the dissociation of RAP80 from the damage site and CTIP-dependent DNA resection and homologous recombination. NPM1 SUMOylation is required for recruitment of DNA repair proteins at the early stage of DNA-damage response (DDR), and SUMOylated NPM1 impacts the assembly of the BRCA1 complex. Knockdown of hCINAP also sensitizes a patient-derived xenograft (PDX) mouse model to chemotherapy. In clinical AML samples, low hCINAP expression is associated with a higher overall survival rate in patients. These results provide mechanistic insight into the function of hCINAP during the DNA-damage response and its role in AML resistance to therapy.

Maternal Overfeeding during Lactation Impairs the Metabolic Response to Fed/Fasting Changing Conditions in the Postweaning Offspring.

SCOPE: The metabolic response to fed/fasting changing conditions at early age in rats with different predisposition to obesity-related alterations due to maternal conditions during the perinatal period is studied. METHODS AND RESULTS: Offspring of dams made obese by a cafeteria diet and moved to a normal-fat diet 1 month before gestation (O-PCaf, with an apparently normal phenotype in adulthood), and offspring of cafeteria diet-fed dams during lactation (O-CAF, with a thin-outside-fat inside phenotype), together with the offspring of control dams (O-C), are studied at early age. Fasting is associated with downregulation of lipogenesis-related genes in liver and rpWAT, and upregulation of genes related to lipolysis and fatty acid uptake in rpWAT in O-C animals. The response to fed/fasting conditions is impaired in O-CAF, but not in O-PCaf animals. The fasting-induced increase in the expression of Prkaa1 in liver and rpWAT, and the corresponding increase of hepatic AMPKα1 protein levels of O-C animals are attenuated in O-CAF rats, while no alterations are found in O-PCaf animals versus controls. CONCLUSION: Maternal intake of a cafeteria diet during lactation causes early alterations in the offspring, impairing their metabolic flexibility in response to fed/fasting changing conditions, which may contribute to hindering energy homeostasis maintenance.

LncRNA LINP1 regulates acute myeloid leukemia progression via HNF4α/AMPK/WNT5A signaling pathway.

LncRNAs play critical roles in various pathophysiological and biological processes, such as protein translation, RNA splicing, and epigenetic modification. Indeed, abundant evidences demonstrated that lncRNA act as competing endogenous RNAs (ceRNAs) to participate in tumorigenesis. However, little is known about the underlying function of lncRNA in nonhomologous end joining (NHEJ) pathway 1 (LINP1) in pediatric and adolescent acute myeloid leukemia (AML). The expression of LINP1 was examined in AML patient samples by qRT-PCR. Cell proliferation was examined by CCK-8 and Edu assays. ß-Galactosidase senescence assay, mGlucose uptake assay, lactate production assay, and Gene Ontology (GO) analysis were performed for functional analysis. We found that LINP1 was significantly overexpressed in AML patients at diagnosis, whereas downregulated after complete remission (CR). Furthermore, knockdown of LINP1 expression remarkably suppressed glucose uptake and AML cell maintenance. Mechanistically, LINP1 was found to inhibit the glucose metabolism by suppressing the expression of HNF4a. Both LINP1 and HNF4a knockdown reduced the expression levels of AMPK phosphorylation and WNT5A, indicating for the first time that LINP1 strengthened the HNF4a-AMPK/WNT5A signaling pathway involved in cell glucose metabolism modulation and AML cell survival. Taken together, our results indicated that LINP1 promotes the malignant phenotype of AML cells and stimulates glucose metabolism, which can be regarded as a potential prognostic marker and therapeutic target for AML.

Dietary ß-Cryptoxanthin Inhibits High-Refined Carbohydrate Diet-Induced Fatty Liver via Differential Protective Mechanisms Depending on Carotenoid Cleavage Enzymes in Male Mice.

BACKGROUND: ß-Cryptoxanthin (BCX), a provitamin A carotenoid shown to protect against nonalcoholic fatty liver disease (NAFLD), can be cleaved by ß-carotene-15,15'-oxygenase (BCO1) to generate vitamin A, and by ß-carotene-9',10'-oxygenase (BCO2) to produce bioactive apo-carotenoids. BCO1/BCO2 polymorphisms have been associated with variations in plasma carotenoid amounts in both humans and animals. OBJECTIVES: We investigated whether BCX feeding inhibits high refined-carbohydrate diet (HRCD)-induced NAFLD, dependent or independent of BCO1/BCO2. METHODS: Six-week-old male wild-type (WT) and BCO1-/-/BCO2-/- double knockout (DKO) mice were randomly fed HRCD (66.5% of energy from carbohydrate) with or without BCX (10 mg/kg diet) for 24 wk. Pathological and biochemical variables were analyzed in the liver and mesenteric adipose tissues (MATs). Data were analyzed by 2-factor ANOVA. RESULTS: Compared to their respective HRCD controls, BCX reduced hepatic steatosis severity by 33‒43% and hepatic total cholesterol by 43‒70% in both WT and DKO mice (P < 0.01). Hepatic concentrations of BCX, but not retinol and retinyl palmitate, were 33-fold higher in DKO mice than in WT mice (P < 0.001). BCX feeding increased the hepatic fatty acid oxidation protein peroxisome proliferator-activated receptor-α, and the cholesterol efflux gene ATP-binding cassette transporter5, and suppressed the lipogenesis gene acetyl-CoA carboxylase 1 (Acc1) in the MAT of WT mice but not DKO mice (P < 0.05). BCX feeding decreased the hepatic lipogenesis proteins ACC and stearoyl-CoA desaturase-1 (3-fold and 5-fold) and the cholesterol synthesis genes 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase and HMG-CoA synthase 1 (2.7-fold and 1.8-fold) and increased the cholesterol catabolism gene cholesterol 7α-hydroxylase (1.9-fold) in the DKO but not WT mice (P < 0.05). BCX feeding increased hepatic protein sirtuin1 (2.5-fold) and AMP-activated protein kinase (9-fold) and decreased hepatic farnesoid X receptor protein (80%) and the inflammatory cytokine gene Il6 (6-fold) in the MAT of DKO mice but not WT mice (P < 0.05). CONCLUSION: BCX feeding mitigates HRCD-induced NAFLD in both WT and DKO mice through different mechanisms in the liver-MAT axis, depending on the presence or absence of BCO1/BCO2.

Sorafenib kills liver cancer cells by disrupting SCD1-mediated synthesis of monounsaturated fatty acids via the ATP-AMPK-mTOR-SREBP1 signaling pathway.

Sorafenib is a multikinase inhibitor that is effective in treating advanced liver cancer. Although its mechanism of action through several established cancer-related protein kinase targets is well-characterized, sorafenib induces variable responses among human tumors, and the cause for this variation is yet unknown. To investigate the underlying mechanisms, we applied mass spectrometry-based proteomic analysis to Huh7.5 human liver cancer cells and found that sorafenib significantly affected the expression of the key lipogenic enzymes, especially stearoyl coenzyme A desaturase 1 (SCD1), in these cells. Given that SCD1 catalyzes the most crucial and rate-limiting step in the synthesis of monounsaturated fatty acids (FAs), we performed a lipidomic analysis, which showed a dramatically altered lipid profile in sorafenib-treated cells. Detection and analysis of free FAs showed that the levels of monounsaturated FAs, including oleate, were significantly decreased in those cells treated by sorafenib. Addition of oleate protected liver cancer cells from sorafenib-induced death and alleviated the abnormalities of mitochondrial morphology and function caused by the drug. Treatment with sorafenib suppressed ATP production, resulting in AMPK activation via phosphorylation. Further secondary effects included reduction of the levels of sterol regulatory element-binding protein 1 (SREBP1) and the phosphorylation of mammalian target of rapamycin (mTOR) in liver cancer cells. These effects were partly abolished in the presence of compound C (an AMPK inhibitor) and ATP and adenosine, and SREBP1c overexpression also could be resistant to the effects of sorafenib, suggesting that the sorafenib-induced reduction in cell viability was mediated by the ATP-AMPK-mTOR-SREBP1 signaling pathway. Taken together, our results suggest that sorafenib's anticancer activity in liver cancer cells is based on the inhibition of ATP production, SCD1 expression, and monounsaturated FA synthesis. In addition, the decreased monounsaturated FA synthesis further triggered the more serious reduction of ATP production in sorafenib-treated cells. To our knowledge, this is the first evidence that sorafenib disrupts lipogenesis and triggers liver cancer cell death by targeting SCD1 through the ATP-AMPK-mTOR-SREBP1 pathway.-Liu, G., Kuang, S., Cao, R., Wang, J., Peng, Q., Sun, C. Sorafenib kills liver cancer cells by disrupting SCD1-mediated synthesis of monounsaturated fatty acids via the ATP-AMPK-mTOR- SREBP1 signaling pathway.

Role of AMPK and its molecular intermediates in subjugating cancer survival mechanism.

The gradual energy dissipation of all organisms allows adapting to energy demands. Pathological situations of uncured diseases such as cancer, diabetes, and other obesity-related diseases are caused by an abrupt energy imbalance. As an energy sensor, AMP-activated kinase (AMPK) can regulate the cellular energy status. In case of increased energy demands or insufficient nutrient supply, cells digest their own interior, which is called autophagy. AMPK-mediated autophagy regulates various metabolic and physiological processes and is dysregulated in different chronic conditions. Because of AMPK's critical role in physiology and pathology, it is an emerging target for both prevention and treatment of these uncured diseases. This review discusses the multifaceted role of AMPK on cancer cell survival and inhibition mechanism. First, we discuss the dual role of AMPK on cancer progression and suppression, and we discuss how different AMPK subunit combinations influence the tumor progression and suppression. Next, we discuss what could be the centering point of AMPK that supports promotion or inhibition of the cancer cell growth. Furthermore, we review the role of connecting mechanism of AMPK-mediated molecular intermediates on cancer cell survival and inhibition pathways. Finally, we discuss how AMPK can affect DNA damage and repairing mechanisms, and immune response of host cell and cancer cells.

AMP-activated protein kinase regulates glycocalyx impairment and macrophage recruitment in response to low shear stress.

Low shear stress (LSS) increases degradation of the endothelial glycocalyx, leading to production of endothelial inflammation and atherosclerosis. However, the underlying mechanisms of how LSS diminishes the endothelial glycocalyx remain unclear. We showed that LSS inactivated AMPK, enhanced Na+-H+ exchanger (NHE)1 activity, and induced glycocalyx degradation. Activation of AMPK prevented LSS-induced NHE1 activity and endothelial glycocalyx impairment. We further identified hyaluronidase 2 (HYAL2) as a mediator of endothelial glycocalyx impairment in HUVECs exposed to LSS. Inactivation of AMPK by LSS up-regulates the activity of HYAL2, which acts downstream of NHE1. We characterized a left common carotid artery partial ligation (PL) model of LSS in C57BL/6 mice. The results showed decreased expression of hyaluronan (HA) in the endothelial glycocalyx and decreased thickness of the endothelial glycocalyx in PL mice. Pharmacological activation of AMPK by ampkinone not only attenuated glycocalyx impairment due to HA degradation but also blocked vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 expression increase and macrophage recruitment in the endothelia of PL mice. Our results revealed that AMPK dephosphorylation induced by LSS activates NHE1 and HYAL2 to promote HA degradation and glycocalyx injury, which may contribute to endothelial inflammatory reaction and macrophage recruitment.-Zhang, J., Kong, X., Wang, Z., Gao, X., Ge, Z., Gu, Y., Ye, P., Chao, Y., Zhu, L., Li, X., Chen, S. AMP-activated protein kinase regulates glycocalyx impairment and macrophage recruitment in response to low shear stress.

Metformin Reduces Lipotoxicity-Induced Meta-Inflammation in ß-Cells through the Activation of GPR40-PLC-IP3 Pathway.

BACKGROUND AND PURPOSE: Metformin, a widely used antidiabetic drug, has been shown to have anti-inflammatory properties; nevertheless, its influence on ß-cell meta-inflammation remains unclear. The following study investigated the effects of metformin on meta-inflammatory in ß-cells and whether the underlying mechanisms were associated with the G protein-coupled receptor 40-phospholipase C-inositol 1, 4, 5-trisphosphate (GPR40-PLC-IP3) pathway. MATERIALS AND METHODS: Lipotoxicity-induced ß-cells and the high-fat diet-induced obese rat model were used in the study. RESULTS: Metformin-reduced lipotoxicity-induced ß-cell meta-inflammatory injury was associated with the expression of GPR40. GPR40 was involved in metformin reversing metabolic inflammation key marker TLR4 activation-mediated ß-cell injury. Furthermore, downstream signaling protein PLC-IP3 of GPR40 was involved in the protective effect of metformin on meta-inflammation, and the above process of metformin was partially regulated by AMPK activity. In addition, the anti-inflammatory effects of metformin were observed in obese rats. CONCLUSION: Metformin can reduce lipotoxicity-induced meta-inflammation in ß-cells through the regulation of the GPR40-PLC-IP3 pathway and partially via the regulation of AMPK activity.

Garcinol Reduces Obesity in High-Fat-Diet-Fed Mice by Modulating Gut Microbiota Composition.

SCOPE: Obesity has become a major health problem worldwide and is associated with low-grade chronic inflammation and intestinal dysbiosis. This study is conducted to investigate the chemopreventive effects of garcinol, a polyisoprenylated benzophenone derivative isolated from the fruit rind of Garcinia indica. How garcinol protects against obesity in high-fat diet (HFD)-induced mice is delineated and whether its anti-obesity effects are related to gut microbiota has been determined. METHODS AND RESULTS: The results show that garcinol reduces HFD-fed mice body weight gain and relative visceral adipose tissue fat weight in a dose-dependent manner. Furthermore, garcinol markedly reduces the plasma levels of glutamate pyruvate transaminase, total cholesterol, and triacylglycerol. The 16S rRNA gene sequence data indicate that garcinol not only reverses HFD-induced gut dysbiosis-as indicated by the decreased Firmicutes-to-Bacteroidetes ratios-but also controls inflammation by increasing the intestinal commensal bacteria, Akkermansia. In addition, the AMP-activated protein kinase α signaling pathway involved in adipocyte adipogenesis is also affected by garcinol. CONCLUSION: Taken together, these results demonstrate for the first time that garcinol can prevent HFD-induced obesity and may be used as a novel gut microbiota modulator to prevent HFD-induced gut dysbiosis and obesity-related metabolic disorders.

Mitochondria: Potential Targets for Protection in Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) is the leading cause of blindness in older adults in developed countries. The molecular mechanisms of disease pathogenesis remain poorly understood; however, evidence suggests that mitochondrial dysfunction may contribute to the progression of the disease. Studies have shown that mitochondrial DNA lesions are increased in the retinal pigment epithelium (RPE) of human patients with the disease and that the number of these lesions increases with disease severity. Additionally, microscopy of human RPE from patients with dry AMD shows severe disruptions in mitochondrial inner and outer membrane structure, mitochondrial size, and mitochondrial cellular organization. Thus, improving our understanding of mitochondrial dysfunction in dry AMD pathogenesis may lead to the development of targeted therapies. We propose that mitochondrial dysfunction in the RPE can lead to the chronic oxidative stress associated with the disease. Therefore, one protective strategy may involve the use of small molecule therapies that target the regulation of mitochondrial biogenesis and mitochondrial fission and mitophagy.