AMP-activated Protein Kinase Gene Research Articles

AMPK Promotes Larval Metamorphosis of Mytilus coruscus.

Metamorphosis is a critical process in the transition from planktonic life to benthic life for marine invertebrates, which is accompanied by a large amount of energy consumption. Previous studies have proved that AMP-activated protein kinase (AMPK), as a vital energy regulator, plays a prominent role in mediating the growth and development of terrestrial animals. However, its function in the growth and development of marine invertebrates, especially in metamorphosis, remains elusive. This study explored the function of AMPK in the larval metamorphosis of Mytilus coruscus. The full-length cDNA of AMPK genes in M. coruscus was cloned and characterized, which is composed of three subunits, McAMPKα, McAMPKβ, and McAMPKγ. Pharmacological tests demonstrated that through the application of an AMPK activator, AMP substantially enhanced the larval metamorphosis rate (p < 0.05). By contrast, the larval metamorphosis rate decreased significantly after being treated with the AMPK inhibitor Compound C (p < 0.05). McAMPK gene knock-down resulted in a reduction in McAMPK gene expression (p < 0.05), and the larval metamorphosis of M. coruscus was significantly restrained (p < 0.05). These results indicated that AMPK signaling is vital in the larval metamorphosis of M. coruscus, which advances further understanding in exploring the molecular mechanisms in the metamorphosis of marine invertebrate larvae.

Differential expression of AMPK subunit isoforms in subcutaneous adipose tissue of post-mortem subjects with BMI&gt;25kg/m2

AMP-activated protein kinase (AMPK) is a heterotrimeric complex that is made up of α-, β- and γ- subunits isoforms making up various isomers. AMPK has been shown to improve catabolic ATP-generating pathways, making it a promising therapeutic target. Studies have shown that different AMPK isomers are predominant in different tissues. However, determination of the predominant isomer in adipose tissue remains obscure. The goal of this study is to identify the AMPK isomers present in human subcutaneous adipose tissues comparing between lean and overweight/obese subjects. Total RNA from post-mortem subcutaneous adipose tissue was extracted and its quantity and integrity were evaluated using a bioanalyzer before being reverse transcribed to cDNA. Then, by using SYBR-green as a fluorophore detection, quantitative real-time PCR was performed. The relative expression of each target gene was calculated using the comparative 2-∆∆Ct method, and the expression levels of target genes were normalized to that of GAPDH, RPLP0, and HPRT1. Mean differences of AMPK subunits mRNA level for both lean and overweight/obese subjects were determined by Mann-Whitney for two-sample comparisons using SPSS 26.0 (SPSS Inc., USA). This study revealed that in overweight/obese subjects, the gene expression of α1-AMPK was upregulated (2.5-fold) whilst α2-AMPK was downregulated (0.5-fold) when compared to lean controls (p=0.044). There were no differences observed between the β and γ subunits in both lean and overweight/obese subjects. Findings from this study suggests that α1- and α2-AMPK gene expression plays an important role in overweight/obese subjects. Future studies to explore the AMPK gene expressions in visceral adipose tissue and among underweight subjects would further close this knowledge gap.

Epithelial-Mesenchymal Transition Suppresses AMPK and Sensitizes Cancer Cells to Pyroptosis under Energy Stress.

Epithelial–mesenchymal transition (EMT) is implicated in tumor metastasis and therapeutic resistance. It remains a challenge to target cancer cells that have undergone EMT. The Snail family of key EMT-inducing transcription factors directly binds to and transcriptionally represses not only epithelial genes but also a myriad of additional genomic targets that may carry out significant biological functions. Therefore, we reasoned that EMT inherently causes various concomitant phenotypes, some of which may create targetable vulnerabilities for cancer treatment. In the present study, we found that Snail transcription factors bind to the promoters of multiple genes encoding subunits of the AMP-activated protein kinase (AMPK) complex, and expression of AMPK genes was markedly downregulated by EMT. Accordingly, high AMPK expression in tumors correlated with epithelial cell markers and low AMPK expression in tumors was strongly associated with adverse prognosis. AMPK is the principal sensor of cellular energy status. In response to energy stress, AMPK is activated and critically reprograms cellular metabolism to restore energy homeostasis and maintain cell survival. We showed that activation of AMPK by energy stress was severely impaired by EMT. Consequently, EMT cancer cells became hypersensitive to a variety of energy stress conditions and primarily underwent pyroptosis, a regulated form of necrotic cell death. Collectively, the study suggests that EMT impedes the activation of AMPK signaling induced by energy stress and sensitizes cancer cells to pyroptotic cell death under energy stress conditions. Therefore, while EMT promotes malignant progression, it concurrently induces collateral vulnerabilities that may be therapeutically exploited.

Predicting the effectiveness of methotrexate therapy based on basal expression of the AMP-activated protein kinase gene in the blood of patients with rheumatoid arthritis

Objective: to search for an association between basal expression of the AMP-activated protein kinase (adenosine monophosphate-activated protein kinase, AMPK) gene in the blood of patients with rheumatoid arthritis (RA) and disease activity, as well as joint destruction before and after 24 months of methotrexate (MT) therapy.Patients and methods. The study included 40 patients with RA who met the 1987 ACR classification criteria, with a disease duration of not more than 2 years, with a mean age of 47.5±15.5 years. All patients received 15 mg/week of MT. The number of swollen joints (SJC) out of 44, the number of tender joints (TSC) out of 53, the duration of morning stiffness (in minutes) and RA activity were assessed using the DAS28 index. The concentration of CRP and IgM rheumatoid factor (RF), antibodies to cyclic citrullinated peptide (ACCP) were assessed. To evaluate the radiological progression of RA, the Sharp method modified by van der Heijde was used. Gene expression in peripheral blood cells was determined by reverse transcriptase reaction and real-time polymerase chain reaction.Results and discussion. During MT therapy, there was a decrease in disease activity by DAS28 index, CRP level, duration of morning stiffness, SJC and TJC. After 2 years, there were no statistically significant changes in the number of erosions, while the number of joints with narrowing of the joint space increased by the end of the study (p=0.004). Treatment with MT resulted in a decrease in AMPK expression. At the same time, patients who achieved remission had the highest level of AMPK before therapy, as did seronegative patients compared to seropositive ones. Based on the ROC analysis, the threshold value of AMPK gene expression was determined, which makes it possible to predict a high probability of a positive effect of MT therapy.Conclusion. AMPK gene expression is associated with disease activity. Its high initial blood level in RA patients is associated with greater efficiency of MT and, possibly, plays a protective role. With an AMPK gene expression index greater than 3.83, the probability of a positive response to MT is high.

Effects of betanin on AMPK, Sirtuin1, and Sirtuin6 gene expression and inflammatory cytokines levels in peripheral blood mononuclear cells of patients with coronary artery disease

PurposeThis study aims to evaluate the effects of betanin on AMP-activated protein kinase (AMPK), Sirtuin1 (SIRT1) and Sirtuin6 (SIRT6) gene expression as well as the tumour necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) cytokine release in peripheral blood mononuclear cells (PBMCs) of patients with coronary artery disease (CAD) and healthy controls.Design/methodology/approachPBMCs isolated from whole blood of 50 patients with CAD and 48 healthy subjects aged 45 to 60 years were treated with 10 and 20 µM of betanin for 24 h. Real-time polymerase chain reaction was performed to assess gene expression levels of AMPK, SIRT1 and SIRT6. The supernatants of the cultured cells were used to assess the IL-6 and TNF-α protein levels by ELISA.FindingsTreatment with both doses of betanin significantly increased AMPK, SIRT1 and SIRT6 expression in PBMCs of CAD patients compared to control non-treated cells (p < 0.05). In PBMCs of healthy subjects, only treatment with high dose of betanin showed significant increase in AMPK (p = 0.007), SIRT1 (p = 0.013) and SIRT6 (p = 0.024) expression compared to control non-treated cells. Betanin (20 µM) also significantly decreased TNF-α and IL-6 concentrations in the culture supernatants of the CAD patients compared to control non-treated cells (p < 0.001).Originality/valueBetanin could enhance AMPK, SIRT1 and SIRT6 gene expressions in PBMCs and represent a useful complementary treatment to reduce the proinflammatory status accompanied with CAD.

Cloning and characterization of AMP-activated protein kinase genes in Daphnia pulex: Modulation of AMPK gene expression in response to polystyrene nanoparticles

Energy metabolism is essential for almost all organisms. At the molecular level, adenosine monophosphate activated protein kinase (AMPK) plays a vital role in cellular energy homeostasis. Its molecular characterization in invertebrates, including Daphnia pulex, and the understanding of its role in response to environmental contaminants is limited. In this study, three subunits of AMPK (AMPKα, β, and γ) were cloned in D. pulex, and assigned the GenBank accession numbers MT536758, MT536759, and MT536760, respectively. Their full lengths were 2,000, 1,384, and 2594 bp, respectively, and contained open reading frames of 526, 274, and 580 amino acids, respectively. Bioinformatic analysis revealed that the three AMPK subunits all have features representative of the AMPK superfamily, and were correspondingly clustered with each orthologue branch. The three AMPK subunit genes, AMPKα, β, and γ, had the highest similarity to those of other organisms at 82%, 94%, and 71%, respectively. Nanoplastics significantly increased AMPKα expression, but decreased that of AMPKβ and γ. These results identified AMPKα, β, and γ in D. pulex, and showed that they all encode proteins with conserved functional domains. This study provides basic information on how three types of AMPK in aquatic organisms respond to environmental contaminants.

The protective effect of sulforaphane against oxidative stress in granulosa cells of patients with polycystic ovary syndrome (PCOS) through activation of AMPK/AKT/NRF2 signaling pathway

Increased production of reactive oxygen species (ROS) in granulosa cells (GCs) causes oxidative stress (OS) and plays a role in pathogenesis of polycystic ovary syndrome (PCOS). Sulforaphane (SFN) has received a great deal of attention as potent antioxidant because of its ability to induce expression of antioxidant enzymes through nuclear factor (erythroid-derived 2)-like 2 (NRF2) signaling pathway. Therefore, the present study was done to investigate the protective effect of SFN against OS in granulosa-lutein cells (GLCs) of patients with PCOS through activation of AMP-activated protein kinase (AMPK)/AKT/NRF2 signaling pathway. GLCs were isolated from patients with PCOS and healthy fertile women, as control group, during egg retrieval procedure. Level of intracellular ROS and apoptosis was determined in the isolated cells. For investigating the protective effect of SFN against ROS production and apoptosis in GLCs, the cells were cultured for 24 h in the presence or absence of SFN. Finally, expression of AMPK, AKT, and NRF2 proteins and genes was evaluated by western blotting and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The results indicated the increased ROS and apoptosis levels in GLCs isolated from patients with PCOS compared to the control group. Addition of SFN to culture medium of GLCs of patients with PCOS reduced intracellular ROS and apoptosis levels, and increased expression of AMPK, AKT, and NRF2 proteins and genes. Our findings demonstrated the protective effect of SFN against OS by lowering level of ROS and apoptosis possibly through activation of AMPK, AKT, and NRF2 proteins and genes expression.

The Effect of Endurance Training with Crocin Consumption on the Levels of AMPK and NRF1 Gene Expression in the Soleus Muscles of Diabetic Rats

Background: Exercise training and crocin, as a herbal antioxidant, help improve metabolism and insulin sensitivity in type 2 diabetes mellitus (T2D). AMP-activated protein kinase (AMPK) and nuclear respiratory factor 1 (NRF1) involve in the mitochondrial biogenesis pathway and diabetes control. Objective: This study aimed to investigate the effects of high-intensity interval training (HIIT), and low intensity continued training (LICT) in combination with crocin consumption on AMPK and NRF1 gene expression in the muscle tissue of diabetic rats. Methods: In this experimental study, 56 adult rats were divided into eight groups (n = 7), including diabetic (crocin utilization, HIIT, LICT, HIIT with crocin, LICT with crocin, control, sham groups) and healthy control group. The HIIT and LICT groups performed five sessions of training per week for eight weeks, and the crocin consumption groups received 25 mg/kg of crocin daily for eight weeks. Moreover, AMPK and NRF1 genes expression levels were evaluated in different groups using real-time polymerase chain reaction (RT-PCR). Results: According to our results, while induction of diabetes significantly decreased the levels of NRF1 and AMPK gene expression (P ≤ 0.05), training and crocin consumption significantly increased the levels of AMPK and NRF1 gene expression (P ≤ 0.05). Conclusions: It appears that crocin consumption along with HIIT improves diabetes symptoms through AMPK and NRF1 mechanism in diabetic rats.

Role of Snf-\u03b2 in lipid accumulation in the high lipid\u2010producing fungus Mucor circinelloides WJ11

BackgroundMucor circinelloides WJ11 is a high-lipid producing strain and an excellent producer of γ-linolenic acid (GLA) which is crucial for human health. We have previously identified genes that encode for AMP-activated protein kinase (AMPK) complex in M. circinelloides which is an important regulator for lipid accumulation. Comparative transcriptional analysis between the high and low lipid-producing strains of M. circinelloides showed a direct correlation in the transcriptional level of AMPK genes with lipid metabolism. Thus, the role of Snf-β, which encodes for β subunit of AMPK complex, in lipid accumulation of the WJ11 strain was evaluated in the present study.ResultsThe results showed that lipid content of cell dry weight in Snf-β knockout strain was increased by 32 % (from 19 to 25 %). However, in Snf-β overexpressing strain, lipid content of cell dry weight was decreased about 25 % (from 19 to 14.2 %) compared to the control strain. Total fatty acid analysis revealed that the expression of the Snf-β gene did not significantly affect the fatty acid composition of the strains. However, GLA content in biomass was increased from 2.5 % in control strain to 3.3 % in Snf-β knockout strain due to increased lipid accumulation and decreased to 1.83 % in Snf-β overexpressing strain. AMPK is known to inactivate acetyl-CoA carboxylase (ACC) which catalyzes the rate-limiting step in lipid synthesis. Snf-β manipulation also altered the expression level of the ACC1 gene which may indicate that Snf-β control lipid metabolism by regulating ACC1 gene.ConclusionsOur results suggested that Snf-β gene plays an important role in regulating lipid accumulation in M. circinelloides WJ11. Moreover, it will be interesting to evaluate the potential of other key subunits of AMPK related to lipid metabolism. Better insight can show us the way to manipulate these subunits effectively for upscaling the lipid production. Up to our knowledge, it is the first study to investigate the role of Snf-β in lipid accumulation in M. circinelloides.

Caffeic and Chlorogenic Acids Synergistically Activate Browning Program in Human Adipocytes: Implications of AMPK- and PPAR-Mediated Pathways.

Caffeic acid (CA) and chlorogenic acid (CGA) are phenolic compounds claimed to be responsible for the metabolic effects of coffee and tea consumption. Along with their structural similarities, they share common mechanisms such as activation of the AMP-activated protein kinase (AMPK) signaling. The present study aimed to investigate the anti-obesity potential of CA and CGA as co-treatment in human adipocytes. The molecular interactions of CA and CGA with key adipogenic transcription factors were simulated through an in silico molecular docking approach. The expression levels of white and brown adipocyte markers, as well as genes related to lipid metabolism, were analyzed by real-time quantitative PCR and Western blot analyses. Mechanistically, the CA/CGA combination induced lipolysis, upregulated AMPK and browning gene expression and downregulated peroxisome proliferator-activated receptor γ (PPARγ) at both transcriptional and protein levels. The gene expression profiles of the CA/CGA-co-treated adipocytes strongly resembled brown-like signatures. Major pathways identified included the AMPK- and PPAR-related signaling pathways. Collectively, these findings indicated that CA/CGA co-stimulation exerted a browning-inducing potential superior to that of either compound used alone which merits implementation in obesity management. Further, the obtained data provide additional insights on how CA and CGA modify adipocyte function, differentiation and lipid metabolism.

Activation of the AMPK-SIRT1 pathway contributes to protective effects of Salvianolic acid A against lipotoxicity in hepatocytes and NAFLD in mice.

Background: Salvianolic acid A (Sal A), a natural polyphenol compound extracted from Radix Salvia miltiorrhiza (known as Danshen in China), possesses a variety of potential pharmacological activities. The aim of this study is to determine mechanisms of hepatoprotective effects of Sal A against lipotoxicity both in cultured hepatocytes and in a mouse model of fatty liver disease. Methods: High-fat and high-carbohydrate diet (HFCD)-fed C57BL/6J mice were employed to establish hepatic lipotoxicity in a mouse model. Two doses of Sal A were administered every other day via intraperitoneal injection (20 and 40 mg/kg BW, respectively). After a 10-week intervention, liver injury was detected by immunohistochemical and biochemical analyses. For in vitro studies, we used HepG2, a human hepatoma cell line, and exposed them to palmitic acid to induce lipotoxicity. The protective effects of Sal A on palmitic acid-induced lipotoxicity were examined in Sal A-pretreated HepG2 cells. Results: Sal A treatments attenuated body weight gain, liver injury, and hepatic steatosis in mice exposed to HFCD. Sal A pretreatments ameliorated palmitic acid-induced cell death but did not reverse effects of HFCD- or palmitate-induced activations of JNK, ERK1/2, and PKA. Induction of p38 phosphorylation was significantly reversed by Sal A in HFCD-fed mice but not in palmitate-treated HepG2 cells. However, Sal A rescued hepatic AMP-activated protein kinase (AMPK) suppression and sirtuin 1 (SIRT1) downregulation by both HFCD feeding in mice and exposure to palmitate in HepG2 cells. Sal A dose-dependently up-regulated p-AMPK and SIRT1 protein levels. Importantly, siRNA silencing of either AMPK or SIRT1 gene expression abolished the protective effects of Sal A on lipotoxicity. Moreover, while AMPK silencing blocked Sal A-induced SIRT1, silencing of SIRT1 had no effect on Sal A-triggered AMPK activation, suggesting SIRT1 upregulation by Sal A is mediated by AMPK activation. Conclusion: Our data uncover a novel mechanism for hepatoprotective effects of Sal A against lipotoxicity both in livers from HFCD-fed mice and palmitic acid-treated hepatocytes.

Nicotinamide: Oversight of Metabolic Dysfunction Through SIRT1, mTOR, and Clock Genes.

Metabolic disorders that include diabetes mellitus present significant challenges for maintaining the welfare of the global population. Metabolic diseases impact all systems of the body and despite current therapies that offer some protection through tight serum glucose control, ultimately such treatments cannot block the progression of disability and death realized with metabolic disorders. As a result, novel therapeutic avenues are critical for further development to address these concerns. An innovative strategy involves the vitamin nicotinamide and the pathways associated with the silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), the mechanistic target of rapamycin (mTOR), mTOR Complex 1 (mTORC1), mTOR Complex 2 (mTORC2), AMP activated protein kinase (AMPK), and clock genes. Nicotinamide maintains an intimate relationship with these pathways to oversee metabolic disease and improve glucose utilization, limit mitochondrial dysfunction, block oxidative stress, potentially function as antiviral therapy, and foster cellular survival through mechanisms involving autophagy. However, the pathways of nicotinamide, SIRT1, mTOR, AMPK, and clock genes are complex and involve feedback pathways as well as trophic factors such as erythropoietin that require a careful balance to ensure metabolic homeostasis. Future work is warranted to gain additional insight into these vital pathways that can oversee both normal metabolic physiology and metabolic disease.

Irradiation of carotid baroreceptor with low-intensity pulsed ultrasound exerts different metabolic protection in perirenal, epididymal white adipose tissue and interscapular brown adipose tissue of obese rats.

This study was designed to clarify whether the irradiation of carotid baroreceptor (CB) with low-intensity pulsed ultrasound (LIPUS) protects against obesity by rebalancing the autonomic nervous system (ANS). Obesity was induced using a high-fat diet (HFD) for 8weeks in Sprague-Dawley rats. Irradiation with LIPUS was daily (20minutes a day) applied to the right CB. In our study, LIPUS significantly ameliorated metabolic disorders in obese rats. LIPUS partly restored norepinephrine (NE) and acetylcholine (ACH) levels in the perirenal white adipose tissue (PWAT), epididymal white adipose tissue (EWAT), interscapular brown adipose tissue (IBAT), and plasma of obese rats. LIPUS partially rectified the dysregulated AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor (PPAR) α/ɣ pathway in the PWAT, EWAT, and IBAT of obese rats. PPARγ and PPARγ target genes respond more sensitively to HFD and LIPUS in PWAT and EWAT than in IBAT. NE, ACH, uncoupling protein-1, phosphorylated AMPK, PPARα, and PPARα target genes respond more sensitively to HFD and LIPUS in IBAT than in PWAT and EWAT. Conclusion: LIPUS irradiation of CB exerts different metabolic protection in PWAT, EWAT, and IBAT by rebalancing the ANS and rectifying the AMPK/PPARα/ɣ pathway in obese rats.

Annotation of AMP-activated protein kinase genes and its comparative transcriptional analysis between high and low lipid producing strains of Mucor circinelloides.

AMP-activated protein kinase (AMPK) is an important regulator for lipid accumulation, potentially known to have an inhibitory role in lipid synthesis. It inactivates acetyl-CoA carboxylase (ACC), an important regulatory enzyme required for lipid synthesis. However, in Mucor circinelloides, AMPK and its association with lipid accumulation has not been studied yet. To identify AMPK genes in M. circinelloides and to compare their expression levels in high and low lipid-producing strains of M. circinelloides to predict the possible roles of AMPK in lipid metabolism and to select candidate genes for further studies to enhance lipid accumulation. Two genes for α-subunit, one for β-subunit and six for γ-subunit were identified and annotated. Bioinformatic analysis confirmed the presence of typical conserved domains in these genes. Furthermore, transcriptional profiling displayed marked differences in expression kinetics of subunits among the selected strains. The expression of AMPK genes decreased rapidly in WJ11, high lipid producer strain during the lipid accumulation phase while contrasting profile of expression was observed in CBS 277.49, low lipid producer strain. The present study has shown the association of AMPK genes with lipid metabolism at the transcriptional level. The involvement of Snf-α1, Snf-α2, Snf-β, Snf-γ1, Snf-γ4, Snf-γ5 subunits were shown to be more pronounced and could potentially be further explored in future studies.

Insight into AMPK regulation mechanism in vivo and in vitro: Responses to low temperatures in the olive flounder Paralichthys olivaceus.

The olive flounder, Paralichthys olivaceus, is a commercially important maricultured fish in China, Japan, and Korea. Low winter temperatures influence its survival and growth and affect the output of the aquaculture industry. Energy metabolism is essential for fish survival, and the central energy-regulating factor - 5'-AMP-activated protein kinase (AMPK) - plays an important role in responses to cold stress. However, the mechanism of AMPK pathway regulation in fish coping with cold stress remains poorly understood. In the present study, the expression of AMPK and its upstream (LKB1 and CaMKKβ) and downstream genes (SITR1, FOXO1A, and TFAM) in the brain, muscle, and heart was analyzed while the flounder was under cold stress (0.2±0.2°C). The results showed that low temperatures activated LKB1, CaMKKβ, and AMPK genes in the brain, and the activated AMPK induced expression of SITR1, FOXO1A, and TFAM. In the muscle tissue, the expression patterns of these genes presented a trend of initially decreasing and then increasing, and there was a delay in the response to low temperatures. At the cellular level, comparative analysis of the effects of the activator 5-aminoimidazole-4-carboxamide1-β-D-ribofuranoside (AICAR) and inhibitor compound C of the AMPK pathway demonstrated that cold stress was similar to AICAR, which activated the AMPK pathway with hysteresis. Thus, the regulation mechanism of AMPK under cold stress was preliminarily analyzed. In general, AMPK was involved not only in responses to low temperatures but also in energy regulation under cold stress.

AMP-Activated Protein Kinase: Friend or Foe in Cancer?

The AMP-activated protein kinase (AMPK) is activated by energy stress and restores homeostasis by switching on catabolism, while switching off cell growth and proliferation. Findings that AMPK acts downstream of the tumor suppressor LKB1 have suggested that AMPK might also suppress tumorigenesis. In mouse models of B and T cell lymphoma in which genetic loss of AMPK occurred before tumor initiation, tumorigenesis was accelerated, confirming that AMPK has tumor-suppressor functions. However, when loss of AMPK in a T cell lymphoma model occurred after tumor initiation, or simultaneously with tumor initiation in a lung cancer model, the disease was ameliorated. Thus, once tumorigenesis has occurred, AMPK switches from tumor suppression to tumor promotion. Analysis of alterations in AMPK genes in human cancers suggests similar dichotomies, with some genes being frequently amplified while others are mutated. Overall, while AMPK-activating drugs might be effective in preventing cancer, in some cases AMPK inhibitors might be required to treat it.

Effects of age on feeding response: Focus on the rostral C1 neuron and its glucoregulatory proteins.

Older people are likely to develop anorexia of aging. Rostral C1 (rC1) catecholaminergic neurons in rostral ventrolateral medulla (RVLM) are recently discovered its role in food intake control. It is well established that these neurons regulate cardiovascular function. This study aims to determine the effect of age on the function of rostral C1 (rC1) neurons in mediating feeding response. Male Sprague Dawley rats at 3-months (n = 22) and 24-months (n = 22) old were used and further divided into two subgroups; 1) treatment group with 2-deoxy-d-glucose (2DG) and 2) vehicle group. Feeding hormones such as cholecystokinin (CCK), ghrelin and leptin were analysed using enzyme-linked immunosorbent assay (ELISA). Rat brain was carefully dissected to obtain the brainstem RVLM region. Further analysis was carried out to determine the level of proteins and genes in RVLM that were associated with feeding pathway. Protein expression of tyrosine hydroxylase (TH), phosphorylated TH at Serine40 (pSer40TH), AMP-activated protein kinase (AMPK), phosphorylated AMPK (phospho AMPK) and neuropeptide Y Y5 receptor (NPY5R) were determined by western blot. Expression of TH, AMPK and NPY genes were determined by real-time PCR. This study showed that blood glucose level was elevated in young and old rats following 2DG administration. Plasma CCK-8 concentration was higher in the aged rats at basal and increased with 2DG administration in young rats, but the leptin and ghrelin showed no changes. Old rats showed higher TH and lower AMPK mRNA levels. Glucoprivation decreased AMPK mRNA level in young rats and decreased TH mRNA in old rats. Aged rC1 neurons showed higher NPY5R protein level. Following glucoprivation, rC1 neurons produced distinct molecular changes across age in which, in young rats, AMPK phosphorylation level was increased and in old rats, TH phosphorylation level was increased. These findings suggest that glucose-counterregulatory responses by rC1 neurons at least, contribute to the ability of young and old rats in coping glucoprivation. Age-induced molecular changes within rC1 neurons may attenuate the glucoprivic responses. This situation may explain the impairment of feeding response in the elderly.

Long-Term Impact of Neonatal Intake of Oleanolic Acid on the Expression of AMP-Activated Protein Kinase, Adiponectin and Inflammatory Cytokines in Rats Fed with a High Fructose Diet.

AMP-activated protein kinase (AMPK) is known to regulate both glucose and lipid metabolism, which play vital roles in the development of metabolic syndrome. One way of regulating AMPK is through hormonal activation using adiponectin. Patients diagnosed with type-2 diabetes (T2D) and obesity exhibit low adiponectin concentration levels in their blood. Moreover, studies have also shown that inflammatory processes play a significant role in the etiology of these metabolic diseases. In this study, the long-term effects of neonatal intake of oleanolic acid (OA) on the AMPK gene, genes associated with glucose transport and lipid metabolism, adiponectin levels, and inflammatory biomarkers in rats fed with a high fructose diet were investigated. Seven day old pups were randomly divided into five groups and treated as follows; 0.5% dimethylsulphoxide v/v in distilled water vehicle control (CON), oleanolic acid (OA, 60 mg/kg), high fructose diet (HF, 20% w/v), high fructose diet combined with oleanolic acid (HF+OA), and high fructose diet combined with metformin (HF+MET, 500 mg/kg). The treatments were administered once daily until day 14. The rats were then weaned at day 21 and fed standard rat chow and had ad libitum access to plain drinking water until day 112. The quantitative polymerase chain reaction (qPCR) was used to analyze the gene expressions of AMPK, Glut-4, Cpt-1, AdipoR1, AdipoR2, TNF-α, and IL-6 in the skeletal muscles. Bio-Plex Pro magnetic bead-based assay was used to measure plasma levels of inflammatory markers (TNF-α, IL-6, VEGF, and MCP-1) while ELISA kits were used to measure adiponectin concentration in blood plasma. The results obtained in this study showed that neonatal supplementation with OA significantly increased AMPK gene expression approximately ~4-fold in OA fed rats compared to those that were fed with HF alone. In addition, glut-4 gene expression was also significantly higher in the OA treatment group compared to all the other experimental groups except the CON group whereas Cpt-1 gene was more expressed when OA was administered alone. Together, these results indicated that OA can play a role in glucose and lipid metabolism gene regulation. Furthermore, the results showed that the OA group had ~1.5-fold increase in adiponectin concentration when comparedto the HF group. Moreover, HF increased levels of inflammatory cytokines, which was attenuated by neonatal administration of OA. Plasma concentration and gene expression in the skeletal muscle for TNF-α and IL-6 were significantly increased in rats that were treated with HF alone when compared to all the other groups. On the contrary, the high levels of TNF-α and IL-6 were reduced when OA was administered. These findings suggest that intake of oleanolic acid during the neonatal stage of development could be a potential strategic intervention for the long-term prevention of metabolic diseases such as T2D and obesity.

In silico study of protein to protein interaction analysis of AMP-activated protein kinase and mitochondrial activity in three different farm animal species

AMP-activated protein kinase (AMPK) is cellular energy censor which works based on ATP and AMP concentration. This protein interacts with mitochondria in determine its activity to generate energy for cell metabolism purposes. For that, this paper aims to compare the protein to protein interaction of AMPK and mitochondrial activity genes in the metabolism of known animal farm (domesticated) that are cattle (Bos taurus), pig (Sus scrofa) and chicken (Gallus gallus). In silico study was done using STRING V.10 as prominent protein interaction database, followed with biological function comparison in KEGG PATHWAY database. Set of genes (12 in total) were used as input analysis that are PRKAA1, PRKAA2, PRKAB1, PRKAB2, PRKAG1, PRKAG2, PRKAG3, PPARGC1, ACC, CPT1B, NRF2 and SOD. The first 7 genes belong to gene in AMPK family, while the last 5 belong to mitochondrial activity genes. The protein interaction result shows 11, 8 and 5 metabolism pathways in Bos taurus, Sus scrofa and Gallus gallus, respectively. The top pathway in Bos taurus is AMPK signaling pathway (10 genes), Sus scrofa is Adipocytokine signaling pathway (8 genes) and Gallus gallus is FoxO signaling pathway (5 genes). Moreover, the common pathways found in those 3 species are Adipocytokine signaling pathway, Insulin signaling pathway and FoxO signaling pathway. Genes clustered in Adipocytokine and Insulin signaling pathway are PRKAA2, PPARGC1A, PRKAB1 and PRKAG2. While, in FoxO signaling pathway are PRKAA2, PRKAB1, PRKAG2. According to that, we found PRKAA2, PRKAB1 and PRKAG2 are the common genes. Based on the bioinformatics analysis, we can demonstrate that protein to protein interaction shows distinct different of metabolism in different species. However, further validation is needed to give a clear explanation.

Establishment of a mice model with liver-specific AMP-activated protein kinase gene knockout

AMP-activated protein kinase (AMPK) is involved in the development and progression of tumors including hepatocellular carcinoma (HCC). However, studies on AMPK and tumorigenesis were largely based on experiments in vitro or tumor xenografts model. Here, we introduce a liver-specific AMPKα1 knockout mice model, which is achieved by Alb-Cre recombinase system. The expression of AMPKα1 in the liver of AMPKα1 -/--Alb-Cre mice is absent. AMPKα1 knockout in the liver does not affect the growth and histological structure of mouse liver. This model provides a favorable tool to the study of the roles of AMPKα1 in liver metabolism or tumorigenesis.