Novel small-molecule AMP-activated protein kinase allosteric activator with beneficial effects in db/db mice

Discovery and evaluation of biphenyl derivatives of 2-iminobenzimidazoles as prototype dual PTP1B inhibitors and AMPK activators with in vivo antidiabetic activity

This work describes the synthesis of series hydrobromides of N-(4-biphenyl)methyl-N'-dialkylaminoethyl-2-iminobenzimidazoles, which, due to the presence of two privileged structural fragments (benzimidazole and biphenyl moieties), can be considered as bi-privileged structures. Compound 7a proved to activate AMP-activated kinase (AMPK) and simultaneously inhibit protein tyrosine phosphatase 1B (PTP1B) with similar potency. This renders it an interesting prototype of potential antidiabetic agents with a dual-target mechanism of action. Using prove of concept in vivo study, we show that dual-targeting compound 7a has a disease-modifying effect in a rat model of type 2 diabetes mellitus via improving insulin sensitivity and lipid metabolism.

Hernandezine, a natural herbal alkaloid, ameliorates type 2 diabetes by activating AMPK in two mouse models

BACKGROUND

AMP-activated protein kinase (AMPK) is an effective target for treating diabetes. However, successful drug development is delayed due to issues including toxicity. Plant-derived natural product AMPK activators have emerged as a new way to treat diabetes due to its potential low safety risks. Here, we studied the effect of hernandezine (HER), a natural product derived from Thalictrum, in activating AMPK and treating T2D in mouse models.

METHOD

We tested HER in various cells and tissues, including primary hepatocytes, skeletal myotubes cell lines, as well as major metabolic tissues from diabetic (db/db) and diet-induced obesity (DIO) model mice. The effect of HER on glucose uptake via AMPK in vitro and in vivo was confirmed utilizing cell transfection and adenovirus interference analysis. Tissue staining assessed the effect of HER on adipogenesis. Real-time quantitative polymerase chain reaction (real-time PCR) was applied to verify the effect of HER on transcription factors. Western blot analysis was used to determine the activation of phosphorylated AMPK and ACC pathways.

RESULTS

Biochemically, we found that HER prevented pAMPK from dephosphorylation to prolong its activity, disproving previous direct activation model and providing a new model to explain HER-mediated AMPK activation. HER could be orally delivered to animals and has a 3-fold long half-life in vivo as compared to metformin. Importantly, long-term oral HER treatment potently reduced body weight and blood glucose in both type 2 diabetes mullitus (T2DM) mouse models by increasing glucose disposal and reducing lipogenesis, and appeared not to induce cardiac hypertrophy.

CONCLUSION

Natural product HER indirectly activates AMPK by suppressing its dephosphorylation. Oral HER effectively alleviated hyperglycemia and reduced body weight in T2D mouse models, appeared to have a low risk of causing cardiac hypertrophy, and might be a potential therapeutic option for T2DM.

Circadian rhythm modulates endochondral bone formation via MTR1/AMPKβ1/BMAL1 signaling axis

The circadian clock is a master regulator in coordinating daily oscillations of physiology and behaviors. Nevertheless, how the circadian rhythm affects endochondral ossification is poorly understood. Here we showed that endochondral bone formation exhibits circadian rhythms, manifested as fast DNA replication in the daytime, active cell mitosis, and matrix synthesis at night. Circadian rhythm disruption led to endochondral ossification deformities. The mechanistic dissection revealed that melatonin receptor 1 (MTR1) periodically activates the AMPKβ1 phosphorylation, which then orchestrates the rhythms of cell proliferation and matrix synthesis via destabilizing the clock component CRY1 and triggering BMAL1 expression. Accordingly, the AMPKβ1 agonist is capable of alleviating the abnormity of endochondral ossification caused by circadian dysrhythmias. Taken together, these findings indicated that the central circadian clock could control endochondral bone formation via the MTR1/AMPKβ1/BMAL1 signaling axis in chondrocytes. Also, our results suggested that the AMPKβ1 signaling activators are promising medications toward endochondral ossification deformities.

Parental energy-sensing pathways control intergenerational offspring sex determination in the nematode Auanema freiburgensis

BACKGROUND

Environmental stimuli experienced by the parental generation influence the phenotype of subsequent generations (Demoinet et al., Proc Natl Acad Sci U S A 114:E2689-E2698, 2017; Burton et al., Nat Cell Biol 19:252-257, 2017; Agrawal et al., Nature 401:60-63, 1999). The effects of these stimuli on the parental generation may be passed through the germline, but the mechanisms at the basis of this non-Mendelian type of inheritance, their level of conservation, how they lead to adaptive vs non-adaptive, and intergenerational vs transgenerational inheritance are poorly understood. Here we show that modulation of nutrient-sensing pathways in the parental generation of the nematode Auanema freiburgensis regulates phenotypic plasticity of its offspring.

RESULTS

In response to con-specific pheromones indicative of stress, AMP-activated protein kinase (AMPK), mechanistic target of rapamycin complex 1 (mTORC1), and insulin signaling regulate stress resistance and sex determination across one generation, and these effects can be mimicked by pathway modulators. The effectors of these pathways are closely associated with the chromatin, and their regulation affects the chromatin acetylation status in the germline.

CONCLUSION

These results suggest that highly conserved metabolic sensors regulate phenotypic plasticity through regulation of subcellular localization of their effectors, leading to changes in chromatin acetylation and epigenetic status of the germline.

AMP-independent activator of AMPK for treatment of mitochondrial disorders

Mitochondrial diseases are a clinically heterogenous group of disorders caused by respiratory chain dysfunction and associated with progressive, multi-systemic phenotype. There is no effective treatment or cure, and no FDA-approved drug for treating mitochondrial disease. To identify and characterize potential therapeutic compounds, we developed an in vitro screening assay and identified a group of direct AMP-activated protein kinase (AMPK) activators originally developed for the treatment of diabetes and metabolic syndrome. Unlike previously investigated AMPK agonists such as AICAR, these compounds allosterically activate AMPK in an AMP-independent manner, thereby increasing specificity and decreasing pleiotropic effects. The direct AMPK activator PT1 significantly improved mitochondrial function in assays of cellular respiration, energy status, and cellular redox. PT1 also protected against retinal degeneration in a mouse model of photoreceptor degeneration associated with mitochondrial dysfunction and oxidative stress, further supporting the therapeutic potential of AMP-independent AMPK agonists in the treatment of mitochondrial disease.

The influence of hypoxia and energy depletion on the response of endothelial cells to the vascular disrupting agent combretastatin A-4-phosphate

Combretastatin A-4 phosphate (CA4P) is a microtubule-disrupting tumour-selective vascular disrupting agent (VDA). CA4P activates the actin-regulating RhoA-GTPase/ ROCK pathway, which is required for full vascular disruption. While hypoxia renders tumours resistant to many conventional therapies, little is known about its influence on VDA activity. Here, we found that active RhoA and ROCK effector phospho-myosin light chain (pMLC) were downregulated in endothelial cells by severe hypoxia. CA4P failed to activate RhoA/ROCK/pMLC but its activity was restored upon reoxygenation. Hypoxia also inhibited CA4P-mediated actinomyosin contractility, VE-cadherin junction disruption and permeability rise. Glucose withdrawal downregulated pMLC, and coupled with hypoxia, reduced pMLC faster and more profoundly than hypoxia alone. Concurrent inhibition of glycolysis (2-deoxy-D-glucose, 2DG) and mitochondrial respiration (rotenone) caused profound actin filament loss, blocked RhoA/ROCK signalling and rendered microtubules  CA4P-resistant. Withdrawal of the metabolism inhibitors restored the cytoskeleton and CA4P activity. The AMP-activated kinase AMPK was investigated as a potential mediator of pMLC downregulation. Pharmacological AMPK activators that generate AMP, unlike allosteric activators, downregulated pMLC but only when combined with 2DG and/or rotenone. Altogether, our results suggest that Rho/ROCK and actinomyosin contractility are regulated by AMP/ATP levels independently of AMPK, and point to hypoxia/energy depletion as potential modifiers of CA4P response.

AMP-activated protein kinase slows D2 dopamine autoreceptor desensitization in substantia nigra neurons

Dopamine neurons in the substantia nigra zona compacta (SNC) are well known to express D2 receptors. When dopamine is released from somatodendritic sites, activation of D2 autoreceptors suppresses dopamine neuronal activity through activation of G protein-coupled K⁺ channels. AMP-activated protein kinase (AMPK) is a master enzyme that acts in somatic tissues to suppress energy expenditure and encourage energy production. We hypothesize that AMPK may also conserve energy in central neurons by reducing desensitization of D2 autoreceptors. We used whole-cell patch-clamp recordings to study the effects of AMPK activators and inhibitors on D2 autoreceptor-mediated current in SNC neurons in midbrain slices from rat pups (11-23 days post-natal). Slices were superfused with 100 μM dopamine or 30 μM quinpirole for 25 min, which evoked outward currents that decayed slowly over time. Although the AMPK activators A769662 and ZLN024 significantly slowed rundown of dopamine-evoked current, slowing of quinpirole-evoked current required the presence of a D1-like agonist (SKF38393). Moreover, the D1-like agonist also slowed the rundown of quinpirole-induced current even in the absence of an AMPK activator. Pharmacological antagonist experiments showed that the D1-like agonist effect required activation of either protein kinase A (PKA) or exchange protein directly activated by cAMP 2 (Epac2) pathways. In contrast, the effect of AMPK on rundown of current evoked by quinpirole plus SKF38393 required PKA but not Epac2. We conclude that AMPK slows D2 autoreceptor desensitization by augmenting the effect of D1-like receptors.

Indirect AMP-Activated Protein Kinase Activators Prevent Incision-Induced Hyperalgesia and Block Hyperalgesic Priming, Whereas Positive Allosteric Modulators Block Only Priming in Mice

AMP-activated protein kinase (AMPK) is a multifunctional kinase that negatively regulates the mechanistic target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) signaling, two signaling pathways linked to pain promotion after injury, such as surgical incision. AMPK can be activated directly using positive allosteric modulators, as well as indirectly through the upregulation of upstream kinases, such as liver kinase B1 (LKB1), which is a mechanism of action of metformin. Metformin's antihyperalgesic effects occur only in male mice, raising questions about how metformin regulates pain sensitivity. We used metformin and other structurally distinct AMPK activators narciclasine (NCLS), ZLN-024, and MK8722, to treat incision-induced mechanical hypersensitivity and hyperalgesic priming in male and female mice. Metformin was the only AMPK activator to have sex-specific effects. We also found that indirect AMPK activators metformin and NCLS were able to reduce mechanical hypersensitivity and block hyperalgesic priming, whereas direct AMPK activators ZLN-024 and MK8722 only blocked priming. Direct and indirect AMPK activators stimulated AMPK in dorsal root ganglion (DRG) neuron cultures to a similar degree; however, incision decreased phosphorylated AMPK (p-AMPK) in DRG. Because AMPK phosphorylation is required for kinase activity, we interpret our findings as evidence that indirect AMPK activators are more effective for treating pain hypersensitivity after incision because they can drive increased p-AMPK through upstream kinases like LKB1. These findings have important implications for the development of AMPK-targeting therapeutics for pain treatment. SIGNIFICANCE STATEMENT: Nonopioid treatments for postsurgical pain are needed. Our work focused on whether direct or indirect AMP-activated protein kinase (AMPK) activators would show greater efficacy for inhibiting incisional pain, and we also tested for potential sex differences. We conclude that indirect AMPK activators are likely to be more effective as potential therapeutics for postsurgical pain because they inhibit acute pain caused by incision and prevent the long-term neuronal plasticity that is involved in persistent postsurgical pain. Our work points to the natural product narciclasine, an indirect AMPK activator, as an excellent starting point for development of therapeutics.

Metformin inhibits β-catenin phosphorylation on Ser-552 through an AMPK/PI3K/Akt pathway in colorectal cancer cells

Several epidemiologic studies have revealed strong inverse associations between metformin use and risk of colorectal cancer development. Nevertheless, the underlying mechanisms are still uncertain. The Wnt/β-catenin pathway, which plays a central role in intestinal homeostasis and sporadic colorectal cancer development, is regulated by phosphorylation cascades that are dependent and independent of Wnt. Here we report that a non-canonical Ser⁵⁵² phosphorylation in β-catenin, which promotes its nuclear accumulation and transcriptional activity, is blocked by metformin via AMPK-mediated PI3K/Akt signaling inhibition.

The adenosine monophosphate-activated protein kinase-vacuolar adenosine triphosphatase-pH axis: A key regulator of the profibrogenic phenotype of human hepatic stellate cells

Liver fibrosis and cirrhosis are characterized by activation of hepatic stellate cells (HSCs), which is associated with higher intracellular pH (pHi). The vacuolar H⁺ adenosine-triphosphatase (v-ATPase) multisubunit complex is a key regulator of pHi homeostasis. The present work investigated the functional role of v-ATPase in primary human HSC (hHSC) activation and its modulation by specific adenosine monophosphate-activated protein kinase (AMPK) subunits. We demonstrate that the expression of different v-ATPase subunits was increased in in vivo and in vitro activated hHSCs compared to nonactivated hHSCs. Specific inhibition of v-ATPase with bafilomycin and KM91104 induced a down-regulation of the HSC fibrogenic gene profile, which coincided with increased lysosomal pH, decreased pHi, activation of AMPK, reduced proliferation, and lower metabolic activity. Similarly, pharmacological activation of AMPK by treatment with diflunisal, A769662, and ZLN024 reduced the expression of v-ATPase subunits and profibrogenic markers. v-ATPase expression was differently regulated by the AMPK α1 subunit (AMPKα1) and AMPKα2, as demonstrated in mouse embryo fibroblasts specifically deficient for AMPK α subunits. In addition, activation of v-ATPase in hHSCs was shown to be AMPKα1-dependent. Accordingly, pharmacological activation of AMPK in AMPKα1-depleted hHSCs prevented v-ATPase down-regulation. Finally, we showed that v-ATPase expression was increased in fibrotic livers from bile duct-ligated mice and in human cirrhotic livers.

CONCLUSION

The down-regulation of v-ATPase might represent a promising target for the development of antifibrotic strategies. (Hepatology 2018).

Inhibition of mitochondrial complex I improves glucose metabolism independently of AMPK activation

Accumulating evidences showed metformin and berberine, well‐known glucose‐lowering agents, were able to inhibit mitochondrial electron transport chain at complex I. In this study, we aimed to explore the antihyperglycaemic effect of complex I inhibition. Rotenone, amobarbital and gene silence of NDUFA13 were used to inhibit complex I. Intraperitoneal glucose tolerance test and insulin tolerance test were performed in db/db mice. Lactate release and glucose consumption were measured to investigate glucose metabolism in HepG2 hepatocytes and C2C12 myotubes. Glucose output was measured in primary hepatocytes. Compound C and adenoviruses expressing dominant negative AMP‐activated protein kinase (AMPK) α1/2 were exploited to inactivate AMPK pathway. Cellular NAD⁺/NADH ratio was assayed to evaluate energy transforming and redox state. Rotenone ameliorated hyperglycaemia and insulin resistance in db/db mice. It induced glucose consumption and glycolysis and reduced hepatic glucose output. Rotenone also activated AMPK. Furthermore, it remained effective with AMPK inactivation. The enhanced glycolysis and repressed gluconeogenesis correlated with a reduction in cellular NAD⁺/NADH ratio, which resulted from complex I suppression. Amobarbital, another representative complex I inhibitor, stimulated glucose consumption and decreased hepatic glucose output in vitro, too. Similar changes were observed while expression of NDUFA13, a subunit of complex I, was knocked down with gene silencing. These findings reveal mitochondrial complex I emerges as a key drug target for diabetes treatment. Inhibition of complex I improves glucose homoeostasis via non‐AMPK pathway, which may relate to the suppression of the cellular NAD⁺/NADH ratio.

Targeting AMPK for the Alleviation of Pathological Pain

Chronic pain is a major clinical problem that is poorly treated with available therapeutics. Adenosine monophosphate-activated protein kinase (AMPK) has recently emerged as a novel target for the treatment of pain with the exciting potential for disease modification. AMPK activators inhibit signaling pathways that are known to promote changes in the function and phenotype of peripheral nociceptive neurons and promote chronic pain. AMPK activators also reduce the excitability of these cells suggesting that AMPK activators may be efficacious for the treatment of chronic pain disorders, like neuropathic pain, where changes in the excitability of nociceptors is thought to be an underlying cause. In agreement with this, AMPK activators have now been shown to alleviate pain in a broad variety of preclinical pain models indicating that this mechanism might be engaged for the treatment of many types of pain in the clinic. A key feature of the effect of AMPK activators in these models is that they can lead to a long-lasting reversal of pain hypersensitivity even long after treatment cessation, indicative of disease modification. Here, we review the evidence supporting AMPK as a novel pain target pointing out opportunities for further discovery that are likely to have an impact on drug discovery efforts centered around potent and specific allosteric activators of AMPK for chronic pain treatment.

In vitro AMPK activating effect and in vivo pharmacokinetics of mogroside V, a cucurbitane-type triterpenoid from Siraitia grosvenorii fruits

The aim of this study was to explore the anti-diabetic effects of mogroside V (MV) and its aglycone mogrol (MO), both isolated from the fruits of Siraitia grosvenorii Swingle, and to investigate the pharmacokinetic behaviors of MV and its metabolite MO in rats.

Administration of Danhong Injection to diabetic db/db mice inhibits the development of diabetic retinopathy and nephropathy

Danhong Injection (DHI), a Chinese medicine for treatment of patients with coronary heart disease, inhibits primary abdominal aortic aneurysms in apoE deficient (apoE^−/−) mice. Formation of microaneurysms plays an important role in the development of diabetic retinopathy and nephropathy. It remains unknown if DHI can reduce these diabetic complications. In this study, diabetic db/db mice in two groups were injected with saline and DHI, respectively, for 14 weeks. Blood and tissue samples were collected to determine serum glucose, lipids and tissue structure. DHI reduced diabetes-induced body weight gain, serum cholesterol and glucose levels. In retinas, DHI blocked the shrink of whole retina and retinal sub-layers by inhibiting expression of caspase 3, matrix metalloproteinase 2 (MMP-2) and MMP-9, accumulation of carbohydrate macromolecules and formation of acellular capillaries. DHI improved renal functions by inhibiting mesangial matrix expansion, expression of vascular endothelial growth factor A, fibronectin and advanced glycation end products in kidneys. Mechanistically, DHI induced expression of glucokinase, AMPKα/phosphorylated AMPKα, insulin receptor substrate 1, fibroblast growth factor 21 and peroxisome proliferator-activated γ. Expression of genes responsible for energy expenditure was also activated by DHI. Therefore, DHI inhibits diabetic retinopathy and nephropathy by ameliorating glucose metabolism and demonstrates a potential application in clinics.

2-(3-Benzoylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid ameliorates metabolic disorders in high-fat diet-fed mice

AIM

Sterol-regulatory element binding proteins (SREBPs) are major transcription factors that regulate liver lipid biosynthesis. In this article we reported a novel synthetic compound 2-(3-benzoylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid (ZJ001) that inhibited the SREBP-1c pathway, and effectively reduced hepatic lipid accumulation in diet-induced obesity (DIO) mice.

METHODS

A luciferase reporter driven by an SRE-containing promoter transfected into HepG2 cells was used to discover the compound. Two approaches were used to evaluate the lipid-lowering effects of ZJ001: (1) diet-induced obesity (DIO) mice that were treated with ZJ001 (15 mg·kg(-1)·d(-1), po) for 7 weeks; and (2) HepG2 cells and primary hepatocytes used as in vitro models.

RESULTS

ZJ001 (10, 20 μmol/L) dose-dependently inhibited the activity of SRE-containing promoter. ZJ001 administration ameliorated lipid metabolism and improved glucose tolerance in DIO mice, accompanied by significantly reduced mRNA levels of SREBP-1C and SREBP-2, and their downstream genes. In HepG2 cells and insulin-treated hepatocytes, ZJ001 (10-40 μmol/L) dose-dependently inhibited lipid synthesis, and reduced mRNA levels of SREBP-1C and SREBP-2, and their downstream genes. Furthermore, ZJ001 dose-dependently increased the phosphorylation of AMPK and regulatory-associated protein of mTOR (Raptor), and suppressed the phosphorylation of mTOR in insulin-treated hepatocytes. Moreover, ZJ001 increased the ADP/ATP ratio in insulin-treated hepatocytes.

CONCLUSION

ZJ001 exerts multiple beneficial effects in diet-induced obesity mice. Its lipid-lowering effects may result from the suppression of mTORC1, which regulates SREBP-1c transcription. The results suggest that the SREBP-1c pathway may be a potential therapeutic target for the treatment of lipid metabolic disorders.

Mitochondrial hormesis and diabetic complications

The concept that excess superoxide production from mitochondria is the driving, initial cellular response underlying diabetes complications has been held for the past decade. However, results of antioxidant-based trials have been largely negative. In the present review, the data supporting mitochondrial superoxide as a driving force for diabetic kidney, nerve, heart, and retinal complications are reexamined, and a new concept for diabetes complications--mitochondrial hormesis--is presented. In this view, production of mitochondrial superoxide can be an indicator of healthy mitochondria and physiologic oxidative phosphorylation. Recent data suggest that in response to excess glucose exposure or nutrient stress, there is a reduction of mitochondrial superoxide, oxidative phosphorylation, and mitochondrial ATP generation in several target tissues of diabetes complications. Persistent reduction of mitochondrial oxidative phosphorylation complex activity is associated with the release of oxidants from nonmitochondrial sources and release of proinflammatory and profibrotic cytokines, and a manifestation of organ dysfunction. Restoration of mitochondrial function and superoxide production via activation of AMPK has now been associated with improvement in markers of renal, cardiovascular, and neuronal dysfunction with diabetes. With this Perspective, approaches that stimulate AMPK and PGC1α via exercise, caloric restriction, and medications result in stimulation of mitochondrial oxidative phosphorylation activity, restore physiologic mitochondrial superoxide production, and promote organ healing.

Anti-inflammatory agents to treat or prevent type 2 diabetes, metabolic syndrome and cardiovascular disease

INTRODUCTION

There is a growing body of evidence to suggest that chronic silent inflammation is a key feature in abdominal obesity, metabolic syndrome, type 2 diabetes (T2DM) and cardiovascular disease (CVD). These observations suggest that pharmacological strategies, which reduce inflammation, may be therapeutically useful in treating obesity, type 2 diabetes and associated CVD.

AREA COVERED

The article covers novel strategies, using either small molecules or monoclonal antibodies. These strategies include: approaches targeting IKK-b-NF-kB (salicylates, salsalate), TNF-α (etanercept, infliximab, adalimumab), IL-1β (anakinra, canakinumab) and IL-6 (tocilizumab), AMP-activated protein kinase activators, sirtuin-1 activators, mammalian target of rapamycin inhibitors and C-C motif chemokine receptor 2 antagonists.

EXPERT OPINION

The available data supports the concept that targeting inflammation improves insulin sensitivity and β-cell function; it also ameliorates glucose control in insulin-resistant patients with inflammatory rheumatoid diseases as well in patients with metabolic syndrome or T2DM. Although promising, the observed metabolic effects remain rather modest in most clinical trials. The potential use of combined anti-inflammatory agents targeting both insulin resistance and insulin secretion appears appealing but remains unexplored. Large-scale prospective clinical trials are underway to investigate the safety and efficacy of different anti-inflammatory drugs. Further evidence is needed to support the concept that targeting inflammation pathways may represent a valuable option to tackle the cardiometabolic complications of obesity.

Berberine promotes glucose consumption independently of AMP-activated protein kinase activation

Berberine is a plant alkaloid with anti-diabetic action. Activation of AMP-activated protein kinase (AMPK) pathway has been proposed as mechanism for berberine’s action. This study aimed to examine whether AMPK activation was necessary for berberine’s glucose-lowering effect. We found that in HepG2 hepatocytes and C2C12 myotubes, berberine significantly increased glucose consumption and lactate release in a dose-dependent manner. AMPK and acetyl coenzyme A synthetase (ACC) phosphorylation were stimulated by 20 µmol/L berberine. Nevertheless, berberine was still effective on stimulating glucose utilization and lactate production, when the AMPK activation was blocked by (1) inhibition of AMPK activity by Compound C, (2) suppression of AMPKα expression by siRNA, and (3) blockade of AMPK pathway by adenoviruses containing dominant-negative forms of AMPKα1/α2. To test the effect of berberine on oxygen consumption, extracellular flux analysis was performed in Seahorse XF24 analyzer. The activity of respiratory chain complex I was almost fully blocked in C2C12 myotubes by berberine. Metformin, as a positive control, showed similar effects as berberine. These results suggest that berberine and metformin promote glucose metabolism by stimulating glycolysis, which probably results from inhibition of mitochondrial respiratory chain complex I, independent of AMPK activation.

AMPK Activators as a Drug for Diabetes, Cancer and Cardiovascular Disease

The cellular mechanisms of AMP-Activated Protein Kinase (AMPK) activators in the treatment and prevention of diabetes, cancer, and cardiovascular disease.

Novel targets of antifibrotic and anti-inflammatory treatment in CKD

Chronic kidney disease (CKD) is becoming a worldwide epidemic, driven largely by the dramatic rise in the prevalence of diabetes and obesity. Novel targets and treatments for CKD are, therefore, desperately needed-to both mitigate the burden of this disease in the general population and reduce the necessity for renal replacement therapy in individual patients. This Review highlights new insights into the mechanisms that contribute to CKD, and approaches that might facilitate the development of disease-arresting therapies for CKD. Particular focus is given to therapeutic approaches using antifibrotic agents that target the transforming growth factor β superfamily. In addition, we discuss new insights regarding the roles of vascular calcification, the NADPH oxidase family, and inflammation in the pathogenesis of CKD. We also highlight a new understanding regarding kidney energy sensing pathways (AMPK, sirtuins, and mTOR) in a variety of kidney diseases and how they are linked to inflammation and fibrosis. Finally, exciting new insights have been made into the role of mitochondrial function and mitochondrial biogenesis in relation to progressive kidney disease. Prospective therapeutics based on these findings will hopefully renew hope for clinicians and patients in the near future.