Carnosic Acid against Lung Cancer: Induction of Autophagy and Activation of Sestrin-2/LKB1/AMPK Signalling.

Non-small cell lung cancer (NSCLC) represents 80% of all lung cancer cases and is characterized by low survival rates due to chemotherapy and radiation resistance. Novel treatment strategies for NSCLC are urgently needed. Liver kinase B1 (LKB1), a tumor suppressor prevalently mutated in NSCLC, activates AMP-activated protein kinase (AMPK) which in turn inhibits mammalian target of rapamycin complex 1 (mTORC1) and activates unc-51 like autophagy activating kinase 1 (ULK1) to promote autophagy. Sestrin-2 is a stress-induced protein that enhances LKB1-dependent activation of AMPK, functioning as a tumor suppressor in NSCLC. In previous studies, rosemary (Rosmarinus officinalis) extract (RE) activated the AMPK pathway while inhibiting mTORC1 to suppress proliferation, survival, and migration, leading to the apoptosis of NSCLC cells. In the present study, we investigated the anticancer potential of carnosic acid (CA), a bioactive polyphenolic diterpene compound found in RE. The treatment of H1299 and H460 NSCLC cells with CA resulted in concentration and time-dependent inhibition of cell proliferation assessed with crystal violet staining and 3H-thymidine incorporation, and concentration-dependent inhibition of survival, assessed using a colony formation assay. Additionally, CA induced apoptosis of H1299 cells as indicated by decreased B-cell lymphoma 2 (Bcl-2) levels, increased cleaved caspase-3, -7, poly (ADP-ribose) polymerase (PARP), Bcl-2-associated X protein (BAX) levels, and increased nuclear condensation. These antiproliferative and proapoptotic effects coincided with the upregulation of sestrin-2 and the phosphorylation/activation of LKB1 and AMPK. Downstream of AMPK signaling, CA increased levels of autophagy marker light chain 3 (LC3), an established marker of autophagy; inhibiting autophagy with 3-methyladenine (3MA) blocked the antiproliferative effect of CA. Overall, these data indicate that CA can inhibit NSCLC cell viability and that the underlying mechanism of action of CA involves the induction of autophagy through a Sestrin-2/LKB1/AMPK signaling cascade. Future experiments will use siRNA and small molecule inhibitors to better elucidate the role of these signaling molecules in the mechanism of action of CA as well as tumor xenograft models to assess the anticancer properties of CA in vivo.

DT-13 inhibits the proliferation of pancreatic cancer by inducing apoptosis via AMPK-mTOR signaling.

BACKGROUND/OBJECTIVE: DT-13, the principal active component of Mysidium shortscapes from the Liliaceae family, has garnered substantial interest in cancer therapy owing to its potential anticancer properties. This study investigated the effects of DT-13 on the proliferation and apoptosis of human pancreatic cancer cell lines and aimed to elucidate the underlying mechanisms. METHODS: PANC1 and CFPAC1 cells were exposed to DT-13 and their proliferation was assessed using RTCA and clone formation assays. Apoptotic protein expression was analyzed by western blotting, and apoptotic cells were identified by flow cytometry. RNA was extracted from DT-13 treated and untreated PANC1 cells for RNA sequencing. Differentially expressed genes were identified and subjected to GO bioprocess, KEGG pathway analysis, and western blotting. Finally, to evaluate tumor growth, CFPAC1 cells were subcutaneously injected into BALB/c nude mice. RESULTS: DT-13 inhibited proliferation and induced apoptosis of PANC1 and CFPAC1 cells by activating the AMPK/mTOR pathway and suppressing p70 S6K. Moreover, DT-13 hindered the growth of CFPAC1 xenograft tumors in nude mice. CONCLUSIONS: DT-13 effectively inhibited the growth of human pancreatic cancer cells.

Phoenixin-20 ameliorates Sevoflurane inhalation-induced post-operative cognitive dysfunction in rats via activation of the PKA/CREB signaling.

Post-operative cognitive dysfunction (POCD) is a common complication after surgery due to the usage of anesthetics, such as Sevoflurane, which severely impacts the life quality of patients. Currently, the pathogenesis of Sevoflurane-induced POCD has not been fully elucidated but is reportedly involved with oxidative stress (OS) injury and aggravated inflammation. Phoenixin-20 (PNX-20) is a PNX peptide consisting of 20 amino acids with promising inhibitory effects on OS and inflammation. Herein, we proposed to explore the potential protective function of PNX-20 on Sevoflurane inhalation-induced POCD in rats. Sprague-Dawley (SD) rats were treated with 100 ng/g PNX-20 for 7 days with or without pre-inhalation with 2.2% Sevoflurane. Markedly increased escape latency and decreased time in the target quadrant in the Morris water maze (MWM) test, and aggravated pathological changes and apoptosis in the hippocampus tissue were observed in Sevoflurane-treated rats, which were markedly attenuated by PNX-20. Furthermore, the aggravated inflammation and OS in the hippocampus observed in Sevoflurane-treated rats were notably abolished by PNX-20. Moreover, the brain-derived neurotrophic factor (BDNF), protein kinase A (PKA), and phospho-cAMP response element binding protein/cAMP response element binding protein (p-CREB/CREB) levels were markedly decreased in Sevoflurane-treated rats, which were memorably increased by PNX-20. Our results indicated that PNX-20 ameliorated Sevoflurane inhalation-induced POCD in rats via the activation of PKA/CREB signaling, which might supply a new treatment approach for POCD.

[Fuyu Decoction improves ventricular remodeling in rats with heart failure by inhibiting AMPK/mTOR pathway-mediated autophagy].

OBJECTIVE: To investigate the effect of Fuyu Decoction on ventricular remodeling and its association with AMPK/mTOR pathway-mediated autophagy in rats with heart failure. METHODS: Thirty male Wistar rat models of heart failure induced by ligation of the left anterior descending coronary artery were divided into model group, Fuyu Decoction treatment group, Fuyu Decoction treatment +AMPK agonist group (n=10), with another 10 rats receiving sham operation as the Sham group. After 8 weeks of drug intervention, the changes of ventricular function and ventricular remodeling indexs of the rats were assessed. TTC staining was used to detect the myocardial infarction area, and HE and Masson staining were used to observe the pathological changes in the myocardial tissue. Western blotting was performed to detect the protein expressions of p-AMPK, p-mTOR, LC3-II, Beclin1 and p62 in the myocardial tissue. RESULTS: Compared with the sham-operated rats, the rat models of heart failure showed significantly increased left ventricular end-diastolic volume (LVEDV), left ventricular endsystolic volume (LVESV), and left ventricular mass index (LVMI) (P < 0.01), reduced left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), and decreased spherical index (SI) were (P < 0.01). The rat models also showed increased myocardial infarction area, obvious myocardial pathologies and fibrosis, increased apoptosis rate of the cardiomyocytes, enhanced myocardial expressions of p-AMPK, LC3-II/LC3-I and Beclin1 (P < 0.01), and reduced expressions of p-mTOR and p62 (P < 0.01). Fuyu Decoction treatment significantly ameliorated these changes in the rat models (all P < 0.01), but its effects were obviously blocked by treatment with EX229. CONCLUSION: Fuyu Decoction can improve ventricular remodeling in rats with heart failure by inhibiting AMPK/mTOR signaling-mediated autophagy in the cardiomyocytes.

Adenosine derivatives from Cordyceps exert antitumor effects against ovarian cancer cells through ENT1-mediated transport, induction of AMPK signaling, and consequent autophagic cell death.

Cordyceps militaris is rich in adenosine derivatives, including 3'-deoxyadenosine, also known as cordycepin. It has been reported for antitumor effects, but its underlying molecular mechanism has yet to be elucidated. We investigated how adenosine derivatives exerted antitumor effects against ovarian cancer using human ovarian cancer cells and a xenograft mouse model. Treatment with adenosine derivatives effectively resulted in cell death of ovarian cancer cells through AMPK activation and subsequently mTOR-mediated autophagic induction. Intriguingly, the effect required membrane transport of adenosine derivatives via ENT1, rather than ADORA-mediated cellular signaling. Our data suggest that adenosine derivatives may be an effective therapeutic intervention in ovarian cancer through induction of ENT1-AMPK-mTOR-mediated autophagic cell death.

Oxytocin ameliorates high glucose- and ischemia/reperfusion-induced myocardial injury by suppressing pyroptosis via AMPK signaling pathway.

The present study aimed to explore the role of oxytocin (OT) in myocardial injury induced by ischemia/reperfusion (I/R) and hyperglycemia and its underlying mechanisms. In this study, the isolated rat hearts underwent I/R in Langendorff perfusion model and H9c2 cells were subjected to hypoxia/reoxygenation (H/R) to establish an in vitro model. I/R injury was induced by exposing the rat hearts to 40 min of global ischemia followed by 60 min of reperfusion. H9c2 cells were cultured under the normoglycemic or hyperglycemic condition with or without pretreatment of OT, and then exposed to 4 h of hypoxia and 2 h of reoxygenation. Measurement indicators included myocardial infarct size assessed by triphenyltetrazolium chloride (TTC) staining and hemodynamic parameters in the ex vivo model as well as cell viability detected by cell counting kit 8 (CCK-8), apoptotic rate evaluated by flow cytometry, and the protein expressions by Western blot. The findings demonstrated that OT attenuated myocardial I/R injury. First, OT preconditioning significantly reduced hemodynamic disorders and myocardial infarct sizes. In addition, OT increased cell viability, decreased cell apoptosis and the expressions of IL-18, IL-1ß, cleaved-caspase-1, NLRP3, and GSDMD following H/R. NLRP3 activator nigericin eliminated the beneficial effects of OT in H9c2 cells. Furthermore, OT also activated AMPK and decreased the expressions of pyroptosis-related proteins. Administration of AMPK inhibitor compound C blunted OT-induced AMPK phosphorylation and elevated the expressions of pyroptosis-related proteins in H9c2 cells subjected to H/R with hyperglycemia. OT alleviates myocardial I/R injury with hyperglycemia by inhibiting pyroptosis via AMPK/NLRP3 signaling pathway.

Arctium lappa leaves based on network pharmacology and experimental validation attenuate atherosclerosis by targeting the AMPK-mediated PPARG/LXRα pathway.

Arctium lappa (A. lappa) leaves are widely used in various traditional Chinese herbal formulae to ameliorate atherosclerosis (AS) and its complications such as stroke; however, there is no literature reporting the anti-atherosclerotic effect and mechanism of A. lappa leaves thus far. In the present study, we used network pharmacology and molecular docking approaches to examine the protective effect and potential mechanism of A. lappa leaves against AS in vivo and in vitro. From the network pharmacology, PPARG, HMGCR and SREBF2 were identified as the core targets of A. lappa leaves against AS. Further enrichment analyses of GO and KEGG pathways suggested that A. lappa leaves might play an anti-AS role by regulating metabolic processes and PPAR signalling pathways. The results of molecular docking experiment revealed that the major components of A. lappa leaves interacted with cholesterol efflux-regulating core proteins (PPARG, LXRα, ABCA1, and ABCG1), AMPK and SIRT1. Both in vivo and in vitro experimental results demonstrated that treatment with A. lappa leaves significantly lowered TC and LDL-C, increased HDL-C, and reduced cholesterol accumulation in the liver and aorta of the AS rat model and the foam cell model. Importantly, both in vivo and in vitro experimental results demonstrated that A. lappa leaves regulate the activity of the PPARG/LXRα signalling and AMPK/SIRT1 signalling pathways. Moreover, after treatment with the AMPK inhibitor Compound C in vitro, the improvement induced by A. lappa leaves was significantly reversed. In conclusion, A. lappa leaves attenuated AS-induced cholesterol accumulation by targeting the AMPK-mediated PPARG/LXRα pathway and promoting cholesterol efflux.

Schaftoside improves cerebral ischemia-reperfusion injury by enhancing autophagy and reducing apoptosis and inflammation through the AMPK/mTOR pathway.

BACKGROUND: As a flavonoid compound, schaftoside (SS) possesses a wide range of pharmaceutical activities. Nonetheless, it is unclear whether SS has a neuroprotective effect in cerebral ischemia-reperfusion injury (CI/RI). OBJECTIVES: To examine the neuroprotective effect of SS in CI/RI and explore the underlying mechanism. MATERIAL AND METHODS: An in vivo middle cerebral artery occlusion (MCAO) was used to simulate CI/RI in rats. Oxygen glucose deprivation/reperfusion (OGD/R) of HT22 cells was used to establish a cellular model of CI/RI in vitro. Pathological changes were evaluated with hematoxylin and eosin (H&E) staining, apoptosis was measured using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and flow cytometry, and inflammatory factors were assessed using enzyme-linked immunosorbent assay (ELISA). Protein expression was detected using western blot or immunofluorescence. RESULTS: Our results indicated that SS attenuated CI/RI by improving neurologic deficits and reducing brain edema. Moreover, SS treatment blocked apoptosis and inflammation and enhanced autophagy in MCAO rats. Schaftoside was found to amplify the activation of adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway induced by MCAO. Similarly, SS pretreatment increased cell viability and autophagy, and reduced apoptosis and inflammation in OGD/R-induced HT22 cells. The OGD/R enlarges the p-AMPK/AMPK ratio while restricting the p-mTOR/mTOR ratio, and it was found that SS further enhanced the effect of OGD/R on the AMPK/mTOR pathway. Rapamycin promoted the effect of SS on OGD/R-induced HT22 cells, while compound C produced the opposite results. Mechanistically, SS promoted autophagy and reduced apoptosis and inflammation through the regulation of the AMPK/mTOR signaling pathway. CONCLUSIONS: The obtained results showed that SS protected against CI/RI through an autophagy-mediated AMPK/mTOR pathway when accessed in vitro and in vivo.

IL-37 alleviates liver granuloma caused by Schistosoma japonicum infection by inducing alternative macrophage activation.

BACKGROUND: Hepatic macrophages regulate liver granuloma formation and fibrosis caused by infection with Schistosoma japonicum, with the manner of regulation dependent on macrophage activation state. Interleukin (IL)-37 may have immunomodulatory effects on macrophages. However, whether IL-37 can affect liver granuloma formation and fibrosis by affecting the polarization of macrophages in S. japonicum infection remains unclear. The aim of this study was to investigate IL-37-affected macrophage polarization in liver granuloma formation and fibrosis in S. japonicum infection. METHODS: An enzyme-linked immunosorbent assay (ELISA) was used to detect the expression of IL-37 in the serum of patients with acute S. japonicum infection and in the serum of healthy people. Recombinant IL-37 (rIL-37), CPP-IgG2Fc-IL-37 and no CPP-IgG2Fc-IL-37 proteins were injected into S. japonicum-infected mice every 3 days for a total of 6 times from day 24 post infection onwards. Subsequently, ELISA, quantitative reverse transcription-PCR, fluorescence-activated cell sorting and western blot were used to analyze whether IL-37 inhibits the formation of liver granulomas and the development of liver fibrosis by regulating the phenotypic transition of macrophages. Finally, the three IL-37 proteins and SIS3, a Smad3 inhibitor, were co-cultured in mouse peritoneal macrophages to explore the mechanism underlying the promotion of the polarization of M0 macrophages to the M2 phenotype by IL-37. RESULTS: Serum IL-37 levels were upregulated in schistosomiasis patients, and this increased level of IL-37 protein apparently alleviated the liver granuloma of mice in infection models. It also could induce liver and peritoneal macrophages to polarize to the M2 phenotype in S. japonicum-infected mice. The S. japonicum-infected mice injected with CPP-IgG2Fc-IL-37 group exhibited the most obvious improvement in inflammatory reaction against the liver granuloma. The number and ratio of M2 macrophages in the liver and peritoneal cavity were significantly higher in the three IL-37 protein groups, especially in the CPP-IgG2Fc-IL-37 group, compared to the controls. Similar results were also found regarding liver function damage. IL-37 induced macrophage M2 polarization by promoting AMP-activated protein kinase (AMPK) phosphorylation in vitro. Among all groups, the activation of AMPK was most significant in the CPP-IgG2Fc-IL-37 group, and it was found that SMAD3 could enhance the anti-inflammatory function of IL-37. CONCLUSIONS: The results show that IL-37 was able to promote the polarization of macrophages to the M2 phenotype, thereby inhibiting the development of schistosomiasis. In comparison to the rIL-37 protein, the CPP-IgG2Fc-IL-37 protein has the advantages of being effective in small doses and having fewer side effects and a better efficacy.

Metformin inhibits the development and metastasis of colorectal cancer.

Metformin is a commonly used drug for the treatment of diabetes. Accumulating evidence suggests that it exerts anti-cancer effects in many cancers, including colorectal cancer. However, the underlying molecular mechanisms of colorectal cancer metastasis remain unclear. Colorectal cancer cell lines were treated with metformin, and cell proliferation, invasion, and migration were analyzed in vitro. The relationship between metformin and the AMPK-mTOR axis was assessed by Western blot analysis and transfection with small interfering RNA. A colorectal cancer xenograft mouse model was used to observe the effects of metformin on liver metastasis. Immunohistochemical analysis was performed on liver metastatic tumors. In in vitro experiments, metformin significantly inhibited the proliferation, migration, and invasion only in HCT116 and SW837 cells, but not in HCT8 and Lovo cells. Only in HCT116 and SW837, a change in AMPK-mTOR expression was observed in a dose-dependent manner. In colorectal cancer xenograft mice, the liver metastatic rate (10% vs. 50%, p = 0.05) and the number of liver metastatic nodules (0.1/body vs. 1.2/body, p = 0.04) were significantly lower in the metformin group. Tumor proliferation and EMT were decreased and apoptosis was promoted only in metastatic liver tumors of mice treated with metformin. The molecular mechanism of the anti-cancer effects of metformin involves repression of mTOR pathways via AMPK activation. Moreover, the differences in metformin sensitivity depend on the response of the AMPK-mTOR pathway to metformin. Our study provides a theoretical basis for the anti-metastatic treatment of colorectal cancer using metformin.

Recent update on application of dihydromyricetin in metabolic related diseases.

As a new type of natural flavonoids, dihydromyricetin (DMY) has attracted more and more attention. It has a series of pharmacological effects, such as anti-inflammatory, anti-tumor, anti-oxidation, antibacterial and so on, and it is almost no toxicity and with excellent safety. Therefore, even if the bioavailability is poor, it is often added to daily food, beverages and even medicines. In recent years, some researchers have found that DMY can treat some diseases by anti-oxidation, anti-inflammation, promoting cell death and regulate the activity of lipid and glucose metabolism. In addition, the mechanism of DMY on these diseases was also related to the signal pathway of AMPK, PI3K/Akt, PPAR and the participation of microRNAs. This review describes the mechanism of DMY in metabolic related diseases from three aspects: metabolic diseases, liver diseases, and cancers, hoping to provide some new ideas for clinical researches.

D-mannose facilitates immunotherapy and radiotherapy of triple-negative breast cancer via degradation of PD-L1.

Breast cancer is the most frequent malignancy in women worldwide, and triple-negative breast cancer (TNBC) patients have the worst prognosis and highest risk of recurrence. The therapeutic strategies for TNBC are limited. It is urgent to develop new methods to enhance the efficacy of TNBC treatment. Previous studies demonstrated that D-mannose, a hexose, can enhance chemotherapy in cancer and suppress the immunopathology of autoimmune diseases. Here, we show that D-mannose can significantly facilitate TNBC treatment via degradation of PD-L1. Specifically, D-mannose can activate AMP-activated protein kinase (AMPK) to phosphorylate PD-L1 at S195, which leads to abnormal glycosylation and proteasomal degradation of PD-L1. D-mannose-mediated PD-L1 degradation promotes T cell activation and T cell killing of tumor cells. The combination of D-mannose and PD-1 blockade therapy dramatically inhibits TNBC growth and extends the lifespan of tumor-bearing mice. Moreover, D-mannose-induced PD-L1 degradation also results in messenger RNA destabilization of DNA damage repair-related genes, thereby sensitizing breast cancer cells to ionizing radiation (IR) treatment and facilitating radiotherapy of TNBC in mice. Of note, the effective level of D-mannose can be easily achieved by oral administration in mice. Our study unveils a mechanism by which D-mannose targets PD-L1 for degradation and provides methods to facilitate immunotherapy and radiotherapy in TNBC. This function of D-mannose may be useful for clinical treatment of TNBC.

The Alzheimer's disease drug candidate J147 decreases blood plasma fatty acid levels via modulation of AMPK/ACC1 signaling in the liver.

J147 is a novel drug candidate developed to treat neurological dysfunction. Numerous studies have demonstrated the beneficial effects of J147 in cellular and animal models of disease which has led to the transitioning of the compound into human clinical trials. However, no biomarkers for its target engagement have been identified. Here, we determined if specific metabolites in the plasma could be indicative of J147's activity in vivo. Plasma lipidomics data from three independent rodent studies were assessed along with liver lipidomics data from one of the studies. J147 consistently reduced plasma free fatty acid (FFA) levels across the independent studies. Decreased FFA levels were also found in the livers of J147-treated mice that correlated well with those in the plasma. These changes in the liver were associated with activation of the AMP-activated protein kinase/acetyl-CoA carboxylase 1 signaling pathway. A reduction in FFA levels by J147 was confirmed in HepG2 cells, where activation of the AMPK/ACC1 pathway was seen along with increases in acetyl-CoA and ATP levels which correlated with enhanced cellular bioenergetics. Our data show that J147 targets liver cells to activate the AMPK/ACC1 signaling pathway and preserve energy at the expense of inhibiting FFA synthesis.

Quercetin for managing type 2 diabetes and its complications, an insight into multitarget therapy.

BACKGROUND: Quercetin, a bioflavonoid abundant in grapefruit, onion, berries, etc., has vast therapeutic potential, especially against Type 2 diabetes and its complications. Quercetin showed similar effects as that of metformin, (widely prescribed antidiabetic drug) in cell lines models (Sajan et al., 2010; Dhanya et al., 2017). In vivo findings also showcase it as a promising agent against diabetes and its pathophysiological complications. SCOPE AND APPROACH: Quercetin can be produced on a large scale through a novel fermentation-based glycosylation strategy from cheap substrates and can be utilized as a dietary supplement. The review focuses on the mounting evidence pointing to Quercetin as a promising candidate for managing type 2 diabetes and its oxidative stress mediated pathophysiological complications. CONCLUSION: Quercetin acts on multiple targets of diabetes and regulates key signalling pathways which improve the symptoms as well as the complications of Type 2 diabetes. However further studies are needed to improve the bioavailability and to establish a dosing regimen for Quercetin.

Oral administration of berberine limits post-traumatic osteoarthritis development and associated pain via AMP-activated protein kinase (AMPK) in mice.

OBJECTIVE: We investigated the effect of berberine, a natural plant product that can activate AMP-activated protein kinase (AMPK), on Osteoarthritis (OA) development and associated pain in mice. DESIGN: Human primary knee chondrocytes were utilized to investigate how AMPK is activated by berberine. Both global knockout (KO) of AMPKα1 and congenic wild type (WT) mice were subjected to the post-traumatic OA through destabilization of medial meniscus (DMM) surgery. Two weeks after surgery, the mice were randomly divided into two groups with one group receiving berberine chloride daily via drinking water and were sacrificed at 6 and 12 weeks after surgery. OA severity was assessed by histological and histomorphometric analyses of cartilage degradation, synovitis, and osteophyte formation. OA-associated pain behavior was also determined. Immunohistochemistry (IHC) analyses were carried out to examine changes in AMPK signaling. RESULTS: Berberine induced phosphorylation of AMPKα (Thr172) via liver kinase B1 (LKB1), the major upstream kinase of AMPK, in chondrocytes in vitro. Both WT and AMPKα1KO developed OA and associated pain post DMM surgery. However, treatment with berberine significantly reduced severity of OA and associated pain in WT but not AMPKα1KO mice. IHC analysis of WT DMM knee cartilage further revealed that berberine inhibited concomitant loss of expression and phosphorylation of AMPKα and expression of SIRT1 and SIRT3, suggesting an important role of activation of AMPK signaling in mediating beneficial effect of berberine. CONCLUSIONS: Berberine acts through AMPK to reduce joint structural damage and pain associated with post-traumatic OA in mice in vivo.

Small molecule QF84139 ameliorates cardiac hypertrophy via activating the AMPK signaling pathway.

Cardiac hypertrophy is a common adaptive response to a variety of stimuli, but prolonged hypertrophy leads to heart failure. Hence, discovery of agents treating cardiac hypertrophy is urgently needed. In the present study, we investigated the effects of QF84139, a newly synthesized pyrazine derivative, on cardiac hypertrophy and the underlying mechanisms. In neonatal rat cardiomyocytes (NRCMs), pretreatment with QF84139 (1-10 µM) concentration-dependently inhibited phenylephrine-induced hypertrophic responses characterized by fetal genes reactivation, increased ANP protein level and enlarged cardiomyocytes. In adult male mice, administration of QF84139 (5-90 mg·kg-1·d-1, i.p., for 2 weeks) dose-dependently reversed transverse aortic constriction (TAC)-induced cardiac hypertrophy displayed by cardiomyocyte size, left ventricular mass, heart weights, and reactivation of fetal genes. We further revealed that QF84139 selectively activated the AMPK signaling pathway without affecting the phosphorylation of CaMKIIδ, ERK1/2, AKT, PKCε, and P38 kinases in phenylephrine-treated NRCMs and in the hearts of TAC-treated mice. In NRCMs, QF84139 did not show additive effects with metformin on the AMPK activation, whereas the anti-hypertrophic effect of QF84139 was abolished by an AMPK inhibitor Compound C or knockdown of AMPKα2. In AMPKα2-deficient mice, the anti-hypertrophic effect of QF84139 was also vanished. These results demonstrate that QF84139 attenuates the PE- and TAC-induced cardiac hypertrophy via activating the AMPK signaling. This structurally novel compound would be a promising lead compound for developing effective agents for the treatment of cardiac hypertrophy.

Orally Induced Hyperthyroidism Regulates Hypothalamic AMP-Activated Protein Kinase.

Besides their direct effects on peripheral metabolic tissues, thyroid hormones (TH) act on the hypothalamus to modulate energy homeostasis. However, since most of the hypothalamic actions of TH have been addressed in studies with direct central administration, the estimation of the relative contribution of the central vs. peripheral effects in physiologic conditions of peripheral release (or administration) of TH remains unclear. In this study we used two different models of peripherally induced hyperthyroidism (i.e., T4 and T3 oral administration) to assess and compare the serum and hypothalamic TH status and relate them to the metabolic effects of the treatment. Peripheral TH treatment affected feeding behavior, overall growth, core body temperature, body composition, brown adipose tissue (BAT) morphology and uncoupling protein 1 (UCP1) levels and metabolic activity, white adipose tissue (WAT) browning and liver metabolism. This resulted in an increased overall uncoupling capacity and a shift of the lipid metabolism from WAT accumulation to BAT fueling. Both peripheral treatment protocols induced significant changes in TH concentrations within the hypothalamus, with T3 eliciting a downregulation of hypothalamic AMP-activated protein kinase (AMPK), supporting the existence of a central action of peripheral TH. Altogether, these data suggest that peripherally administered TH modulate energy balance by various mechanisms; they also provide a unifying vision of the centrally mediated and the direct local metabolic effect of TH in the context of hyperthyroidism.

Graptopetalum paraguayense Extract Ameliorates Proteotoxicity in Aging and Age-Related Diseases in Model Systems.

Declines in physiological functions are the predominant risk factors for age-related diseases, such as cancers and neurodegenerative diseases. Therefore, delaying the aging process is believed to be beneficial in preventing the onset of age-related diseases. Previous studies have demonstrated that Graptopetalum paraguayense (GP) extract inhibits liver cancer cell growth and reduces the pathological phenotypes of Alzheimer's disease (AD) in patient IPS-derived neurons. Here, we show that GP extract suppresses ß-amyloid pathology in SH-SYS5Y-APP695 cells and APP/PS1 mice. Moreover, AMP-activated protein kinase (AMPK) activity is enhanced by GP extract in U87 cells and APP/PS1 mice. Intriguingly, GP extract enhances autophagy in SH-SYS5Y-APP695 cells, U87 cells, and the nematode Caenorhabditis elegans, suggesting a conserved molecular mechanism by which GP extract might regulate autophagy. In agreement with its role as an autophagy activator, GP extract markedly diminishes mobility decline in polyglutamine Q35 mutants and aged wild-type N2 animals in C. elegans. Furthermore, GP extract significantly extends lifespan in C. elegans.

AMPK activators for the prevention and treatment of neurodegenerative diseases.

INTRODUCTION: As the global population ages at an unprecedented rate, the burden of neurodegenerative diseases is expected to grow. Given the profound impact illness like dementia exert on individuals and society writ large, researchers, physicians, and scientific organizations have called for increased investigation into their treatment and prevention. Both metformin and aspirin have been associated with improved cognitive outcomes. These agents are related in their ability to stimulate AMP kinase (AMPK). Momordica charantia, another AMPK activator, is a component of traditional medicines and a novel agent for the treatment of cancer. It is also being evaluated as a nootropic agent. AREAS COVERED: This article is a comprehensive review which examines the role of AMPK activation in neuroprotection and the role that AMPK activators may have in the management of dementia and cognitive impairment. It evaluates the interaction of metformin, aspirin, and Momordica charantia, with AMPK, and reviews the literature characterizing these agents' impact on neurodegeneration. EXPERT OPINION: We suggest that AMPK activators should be considered for the treatment and prevention of neurodegenerative diseases. We identify multiple areas of future investigation which may have a profound impact on patients worldwide.

Metformin attenuates diabetic neuropathic pain via AMPK/NF-κB signaling pathway in dorsal root ganglion of diabetic rats.

Neuropathic pain is a common complication of diabetes mellitus with poorly relieved by conventional analgesics. Metformin, a first-line drug for type 2 diabetes, reduces blood glucose by activating adenosine monophosphate protein kinase (AMPK) signalling system. However, the effect of Metformin on diabetic neuropathic pain is still unknown. In the present study, we showed that Metformin was capable of attenuating diabetes induced mechanical allodynia, and the analgesia effect could be blocked by Compound C (an AMPK inhibitor). Importantly, Metformin enhanced the phosphorylation level of AMPK in L4-6 DRGs of diabetic rats but not affect the expression of total AMPK. Intrathecal injection of AICAR (an AMPK agonist) could activate AMPK and alleviate the mechanical allodynia of diabetic rats. Additionally, phosphorylated AMPK and NF-κB was co-localized in small and medium neurons of L4-6 DRGs. Interestingly, the regulation of NF-κB in diabetic rats was obviously reduced when AMPK was activated by AICAR. Notably, Metformin could decrease NF-κB expression in L4-6 DRGs of diabetic rats, but the decrease was blocked by Compound C. In conclusion, Metformin alleviates diabetic mechanical allodynia via activation of AMPK signaling pathway in L4-6 DRGs of diabetic rats, which might be mediated by the downregulation of NF-κB, and this providing certain basis for Metformin to become a potential drug in the clinical treatment of diabetic neuropathic pain.