Protein Kinase Alpha Research Articles

Afzelin protects against doxorubicin-induced cardiotoxicity by promoting the AMPKα/SIRT1 signaling pathway

BackgroundDoxorubicin (DOX), a chemotherapeutic drug, could relieve the progressions of various diseases. However, its clinical application is limited due to its cardiotoxicity. This study aimed to investigate the effects of afzelin (a flavonol glycoside found in Houttuynia cordata) on the cardiotoxicity induced by DOX. MethodsIn ex-vivo, H9C2 cells were incubated with 20, 40, or 80 μM afzelin for 12 h, followed by the treatment with 1 μM DOX for 12 h. In vivo, C57BL/6 J mice were intraperitoneally injected with 4 mg/kg/day DOX on days 1, 7, and 14. Meanwhile, starting from day 1, mice were intragastrically administrated with 5 mg/kg/day or 10 mg/kg/day afzelin for 20 days. The cardiac function of mice was evaluated by detecting hemodynamic parameters using the M-mode echocardiography. ResultsDOX decreased the cell survival rate, and elevated apoptotic rate, as well as induced the oxidative stress and mitochondrial dysfunction in H9C2 cells. All these changes were alleviated by afzelin treatment in a concentration-dependent manner. The results were further proven by the mitigation of cardiac injury in vivo, as evidenced by the elevation of fractional shortening, heart weight/tibia length, and the rate of the increase/decrease of left ventricular pressure in mice subjected to DOX-induced cardiotoxicity. Furthermore, afzelin upregulated the expression of p-AMP-activated protein kinase alpha (AMPKα) and sirtuin1 (SIRT1). Dorsomorphin (an AMPKα inhibitor) abrogated the anti-cardiotoxicity effects of afzelin in H9C2 cells induced by DOX. ConclusionAfzelin protected against DOX-induced cardiotoxicity by promoting the AMPKα/SIRT1 signaling pathway.

MKP1 promotes nonalcoholic steatohepatitis by suppressing AMPK activity through LKB1 nuclear retention

Nonalcoholic steatohepatitis (NASH) is triggered by hepatocyte death through activation of caspase 6, as a result of decreased adenosine monophosphate (AMP)-activated protein kinase-alpha (AMPKα) activity. Increased hepatocellular death promotes inflammation which drives hepatic fibrosis. We show that the nuclear-localized mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP1) is upregulated in NASH patients and in NASH diet fed male mice. The focus of this work is to investigate whether and how MKP1 is involved in the development of NASH. Under NASH conditions increased oxidative stress, induces MKP1 expression leading to nuclear p38 MAPK dephosphorylation and decreases liver kinase B1 (LKB1) phosphorylation at a site required to promote LKB1 nuclear exit. Hepatic deletion of MKP1 in NASH diet fed male mice releases nuclear LKB1 into the cytoplasm to activate AMPKα and prevents hepatocellular death, inflammation and NASH. Hence, nuclear-localized MKP1-p38 MAPK-LKB1 signaling is required to suppress AMPKα which triggers hepatocyte death and the development of NASH.

A mitochondrial EglN1-AMPKα axis drives breast cancer progression by enhancing metabolic adaptation to hypoxic stress.

Mitochondria play essential roles in cancer cell adaptation to hypoxia, but the underlying mechanisms remain elusive. Through mitochondrial proteomic profiling, we here find that the prolyl hydroxylase EglN1 (PHD2) accumulates on mitochondria under hypoxia. EglN1 substrate-binding region in the β2β3 loop is responsible for its mitochondrial translocation and contributes to breast tumor growth. Furthermore, we identify AMP-activated protein kinase alpha (AMPKα) as an EglN1 substrate on mitochondria. The EglN1-AMPKα interaction is essential for their mutual mitochondrial translocation. After EglN1 prolyl-hydroxylates AMPKα under normoxia, they rapidly dissociate following prolyl-hydroxylation, leading to their immediate release from mitochondria. In contrast, hypoxia results in constant EglN1-AMPKα interaction and their accumulation on mitochondria, leading to the formation of a Ca2+ /calmodulin-dependent protein kinase 2 (CaMKK2)-EglN1-AMPKα complex to activate AMPKα phosphorylation, ensuring metabolic homeostasis and breast tumor growth. Our findings identify EglN1 as an oxygen-sensitive metabolic checkpoint signaling hypoxic stress to mitochondria through its β2β3 loop region, suggesting a potential therapeutic target for breast cancer.

Probiotics Increase Intramuscular Fat and Improve the Composition of Fatty Acids in Sunit Sheep through the Adenosine 5'-Monophosphate-Activated Protein Kinase (AMPK) Signaling Pathway.

This experiment aims to investigate the impact of probiotic feed on growth performance, carcass traits, plasma lipid biochemical parameters, intramuscular fat and triglyceride content, fatty acid composition, mRNA expression levels of genes related to lipid metabolism, and the activity of the enzyme in Sunit sheep. In this experiment, 12 of 96 randomly selected Sunit sheep were assigned to receive the basic diet or the basic diet supplemented with probiotics. The results showed that supplementation with probiotics significantly increased the loin eye area, and decreased plasma triglycerides and free fatty acids, increasing the content of intramuscular fat and triglycerides in the muscle and improving the composition of the fatty acids. The inclusion of probiotics in the diet reduced the expression of adenosine 5'-monophosphate-activated protein kinase alpha 2 (AMPKα2) mRNA and carnitine palmitoyltransferase 1B (CPT1B) mRNA, while increasing the expression of acetyl-CoA carboxylase alpha (ACCα) mRNA, sterol regulatory element-binding protein-1c (SREBP-1c) mRNA, fatty acid synthase mRNA, and stearoyl-CoA desaturase 1 mRNA. The results of this study indicate that supplementation with probiotics can regulate fat deposition and improves the composition of fatty acids in Sunit sheep through the signaling pathways AMPK-ACC-CPT1B and AMPK-SREBP-1c. This regulatory mechanism leads to an increase in intramuscular fat content, a restructuring of muscle composition of the fatty acids, and an enhancement of the nutritional value of meat. These findings contribute to a better understanding of the food science of animal resources and provide valuable references for the production of meat of higher nutritional value.

CFTR potentiator ivacaftor protects against noise-induced hair cell loss by increasing Nrf2 and reducing oxidative stress

Over-production of reactive oxygen species (ROS) in the inner ear can be triggered by a variety of pathological events identified in animal models after traumatic noise exposure. Our previous research found that inhibition of the AMP-activated protein kinase alpha subunit (AMPKα) protects against noise-induced cochlear hair cell loss and hearing loss by reducing ROS accumulation. However, the molecular pathway through which AMPKα exerts its antioxidative effect is still unclear. In this study, we have investigated a potential target of AMPKα and ROS, cystic fibrosis transmembrane conductance regulator (CFTR), and the protective effect against noise-induced hair cell loss of an FDA-approved CFTR potentiator, ivacaftor, in FVB/NJ mice, mouse explant cultures, and HEI-OC1 cells. We found that noise exposure increases phosphorylation of CFTR at serine 737 (p-CFTR, S737), which reduces wildtype CFTR function, resulting in oxidative stress in cochlear sensory hair cells. Pretreatment with a single dose of ivacaftor maintains CFTR function by preventing noise-increased p-CFTR (S737). Furthermore, ivacaftor treatment increases nuclear factor E2-related factor 2 (Nrf2) expression, diminishes ROS formation, and attenuates noise-induced hair cell loss and hearing loss. Additionally, inhibition of noise-induced AMPKα activation by compound C also diminishes p-CFTR (S737) expression. In line with these in-vivo results, administration of hydrogen peroxide to cochlear explants or HEI-OC1 cells increases p-CFTR (S737) expression and induces sensory hair cell or HEI-OC1 cell damage, while application of ivacaftor halts these effects. Although ivacaftor increases Nrf2 expression and reduces ROS accumulation, cotreatment with ML385, an Nrf2 inhibitor, abolishes the protective effects of ivacaftor against hydrogen-peroxide-induced HEI-OC1 cell death. Our results indicate that noise-induced sensory hair cell damage is associated with p-CFTR. Ivacaftor has potential for treatment of noise-induced hearing loss by maintaining CFTR function and increasing Nrf2 expression for support of redox homeostasis in sensory hair cells.

Cepharanthine Exerts Antioxidant and Anti-Inflammatory Effects in Lipopolysaccharide (LPS)-Induced Macrophages and DSS-Induced Colitis Mice.

Cepharanthine (CEP), a biscoclaurine alkaloid extracted from Stephania cepharantha Hayata, has been widely used for the treatment of various acute and chronic diseases, including leukopenia, and snake bites. Here, our objective was to investigate the anti-oxidative stress and anti-inflammatory response effects of CEP in lipopolysaccharide (LPS)-induced macrophages as well as dextran sulfate sodium (DSS)-induced colitis mice. Our findings demonstrated that supplementation with CEP effectively mitigates body weight loss and elevation of disease activity index (DAI), reduces the malondialdehyde (MDA) content to 2.45 nM/mL while increasing the reduced glutathione (GSH) content to 35.53 μg/mL, inhibits inflammatory response, and maintains proper intestinal epithelium tight junctions in DSS-induced wild type (WT) mice. However, it failed to provide protective effects in DSS-induced transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) knockout (NRF2-/-) mice. GSH content decreased to 10.85 μg/106 cells following LPS treatment, whereas supplementation with CEP increased the GSH content to 12.26 μg/106 cells. Moreover, CEP effectively attenuated ROS production in LPS-induced macrophages. Additionally, CEP exhibited inhibitory effects on pro-inflammatory cytokines and mediators in LPS-induced macrophages. Furthermore, we observed that supplementation with CEP promoted the expression of NRF2/heme oxygenase 1 (HO-1)/NADPH quinone oxidoreductase-1 (NQO-1) as well as the phosphorylation of the adenosine monophosphate-activated protein kinase alpha 1 (AMPK-α1)/protein kinase B (AKT)/glycogen synthase kinase-3 beta (GSK-3β) signaling pathway in macrophages while inhibiting the phosphorylation of the extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinase (JNK), and nuclear factor-kappa B p65 (NF-κB p65) signaling pathway in LPS-induced macrophages. Although CEP did not demonstrate inhibitory effects on oxidative stress or promote the expression of HO-1/NQO-1, it effectively activated the phosphorylation of the AMPK-α1/AKT/GSK-3β signaling pathway which is an upstream regulator of NRF2 in LPS-induced primary peritoneal macrophages from NRF2-/- mice. In summary, our findings suggest that CEP exerts protective effects against oxidative stress and inflammatory response by activating the AMPK-α1/AKT/GSK-3β/NRF2 signaling pathway while concurrently inhibiting the activation of mitogen activated protein kinases (MAPKs) and the NF-κB p65 signaling pathway. These results not only elucidate the mechanisms underlying CEP's protective effects on colon oxidative stress and inflammation but also provide evidence supporting NRF2 as a potential therapeutic target for IBD treatment.

Antihyperlipidemic effect of bread fortified with potato peel powder against Triton X-100-induced hyperlipidemia in male albino rats

The present investigation aimed to improve the nutritional and healthy values and evaluate the influence of bread fortified with dried potato peels (BPP) on Triton X-100-induced hyperlipidemia in male albino rats. The findings demonstrated that BPP lowered hepatic triglycerides and total cholesterol while increasing high-density lipoprotein (HDL-C). BPP exhibited potential lipid-lowering and hepatoprotective actions that were generated by the reduction of oxidative damage and preservation of the non-enzymatic and enzymatic antioxidant systems compromised by hyperlipidemic condition. Furthermore, BPP considerably enhanced the mRNA expression of AMPKα (AMP-activated protein kinase-alpha), suppressed the expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase alpha (ACCα), and decreased the mRNA expression of the adipogenic transcription factor SREBP-1c (sterol regulatory element-binding protein-1c), which are essential regulators of hepatocyte lipid metabolism. A histopathological assessment of the liver confirmed the results. In conclusion, this investigation revealed a positive impact of bread fortified with BPP therapy in preventing hyperlipidemia.

Comparing the Efficacy of Carvedilol and Celecoxib to Prednisolone in Acetic Acid-Induced Ulcerative Colitis in Male Albino Rats

Ulcerative colitis refers to destruction of mucosal layer of distal colon and rectum. Exact mechanism for pathophysiology is still unclear but inflammation and oxidative stress may play a caustic role. Neutrophil and monocyte infiltration results in free radical generation which damages intestinal mucosa. Many treatments as steroids are used to reduce inflammation but cannot cause remission. Carvedilol is a third-generation nonselective β-blocker which possesses anti-oxidant, anti-inflammatory properties and can reduce gastric ulceration. Celecoxib is a selective cyclooxygenase -2 (COX-2) inhibitor which decrease risk of gastrointestinal bleeding. The current study was designed to compare the efficacy of carvedilol and celecoxib to prednisolone in acetic acid-induced ulcerative colitis model. A total of 40 adult male albino rats were randomly divided into five groups: Control group: Rats received 2 ml of saline transrectal. Acetic acid (AA) group: Rats were transrectal injected with 2ml acetic acid. Prednisolone +AA group: Rats were pre-treated with prednisolone in a dose 4mg/kg /day. Carvedilol +AA group: Rats were pre-treated with carvedilol in a dose 30 mg/kg/day. Celecoxib +AA group: Rats were pre-treated with celecoxib in a dose 5mg/kg/day. All drugs were given orally for 7 days. At end of experiment, distal colon was removed, one part of specimen was preserved in 10% formalin for histological examination and other part was homogenized for evaluation of tumor necrosis factor alpha (TNF-α), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO) and mitogen-activated protein kinase ( p38 MAPK). Data of present study revealed that treatment of rats with carvedilol or celecoxib before induction of colitis significantly reduced levels of TNF-α, MDA, NO and mRNA level of p38 MAPK while both drugs increased GSH level. Protective effects of Carvedilol and celecoxib are due to anti-inflammatory, anti-oxidant effects and ability to decrease synthesis of MAPK which reduce cytokines signaling in epithelial cells of gut mucosa.

DMC (2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone) enhances exercise tolerance via the AMPK-SIRT1-PGC-1α pathway in mice fed a high-fat diet.

Obesity is caused by an imbalance between energy intake and energy expenditure. This study aimed to determine the effects and mechanisms of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) on exercise tolerance in high-fat diet (HFD)-fed mice. Male C57BL/6J mice were randomly divided into two categories (7 groups [n = 8]): sedentary (control [CON], HFD, 200 mg/kg DMC, and 500 mg/kg DMC) and swimming (HFD, 200 mg/kg DMC, and 500 mg/kg DMC). Except the CON group, all other groups were fed HFD with or without DMC intervention for 33 days. The swimming groups were subjected to exhaustive swimming (three sessions/week). Changes in swimming time, glucolipid metabolism, body composition, biochemical indicators, histopathology, inflammation, metabolic mediators, and protein expression were assessed. DMC combined with regular exercise improved endurance performance, body composition, glucose and insulin tolerance, lipid profile, and the inflammatory state in a dose-dependent manner. Further, DMC alone or combined with exercise could restore normal tissue morphology, reduce fatigue-associated markers, and boost whole-body metabolism and the protein expression of phospho-AMP-activated protein kinase alpha/total-AMP-activated protein kinase alpha (AMPK), sirtuin-1 (SIRT1), peroxisome-proliferator-activated receptor gamma coactivator 1alpha (PGC-1α), and peroxisome proliferator-activated receptor alpha in the muscle and adipose tissues of HFD-fed mice. DMC exhibits antifatigue effects by regulating glucolipid catabolism, inflammation, and energy homeostasis. Furthermore, DMC exerts a synergistic exercise-related metabolic effect via the AMPK-SIRT1-PGC-1α signaling pathway, suggesting that DMC is a potential natural sports supplement with mimicked or augmented exercise effects for obesity prevention.

Acetyl-11-Keto-Beta-Boswellic Acid Has Therapeutic Benefits for NAFLD Rat Models That Were Given a High Fructose Diet by Ameliorating Hepatic Inflammation and Lipid Metabolism.

Acetyl-11-keto-beta-boswellic acid (AKBA), a potent anti-inflammatory compound purified from Boswellia species, was investigated in a preclinical study for its potential in preventing and treating non-alcoholic fatty liver disease (NAFLD), the most common chronic inflammatory liver disorder. The study involved thirty-six male Wistar rats, equally divided into prevention and treatment groups. In the prevention group, rats were given a high fructose diet (HFrD) and treated with AKBA for 6weeks, while in the treatment group, rats were fed HFrD for 6weeks and then given a normal diet with AKBA for 2weeks. At the end of the study, various parameters were analyzed including liver tissues and serum levels of insulin, leptin, adiponectin, monocyte chemoattractant protein-1 (MCP-1), transforming growth factor beta (TGF-β), interferon gamma (INF-ϒ), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α). Additionally, the expression levels of genes related to the inflammasome complex and peroxisome proliferator-activated receptor gamma (PPAR-ϒ), as well as the levels of phosphorylated and non-phosphorylated AMP-activated protein kinase alpha-1 (AMPK-α1) protein, were measured. The results showed that AKBA improved NAFLD-related serum parameters and inflammatory markers and suppressed PPAR-ϒ and inflammasome complex-related genes involved in hepatic steatosis in both groups. Additionally, AKBA prevented the reduction of the active and inactive forms of AMPK-α1 in the prevention group, which is a cellular energy regulator that helps suppress NAFLD progression. In conclusion, AKBA has a beneficial effect on preventing and avoiding the progression of NAFLD by preserving lipid metabolism, improving hepatic steatosis, and suppressing liver inflammation.

CaMKIIα signaling is required for the neuroprotective effects of Dl‐3‐n‐butylphthalide in Alzheimer’s disease

AbstractBackgroundAlzheimer’s disease (AD) is the most common form of neurodegenerative disease and most anti‐AD drugs have failed in clinical trials, hence it is urgent to find effective potential drugs against AD. DL‐3‐n‐Butylphthalide (NBP) is a compound extracted from celery seed and is a multiple‐target drug, and we have demonstrated NBP was effective for improving cognitive and global functioning in patients with subcortical vascular cognitive impairment without dementia and exhibited good safety. Even though there are several studies that have demonstrated the neuroprotective effects of NBP on cognitive impairment, and the mechanisms of NBP remains relatively unexplored.MethodCell viabilities was observed by MTT. Apoptosis and the level of intracellular Ca2+ were examined by flow cytometry. The activation of CaMKIIα signaling was detected by western blotting and immunofluorescence.ResultIn this study, we found that NBP could alleviated the increase of intracellular Ca2+ and reverse down‐regulation of Ca2+/calmodulin‐dependent protein kinase alpha (CaMKIIα) signaling, and rescue neuronal apoptosis in SH‐SY5Y cells treated by Aβ oligomers. Further, we found that these neuroprotection of NBP on neuronal damage and CaMKIIα signaling were abolished when CaMKIIα expression was knock‐downed or its activity was inhibited.ConclusionThus, our findings suggested that CaMKIIα signaling was required for the neuroprotective effects of NBP in AD, and provide an improved basis for elucidation of the mechanism and treatment of NBP in AD.

FAR-INFRARED IRRADIATION INHIBITS CELL PROLIFERATION IN BASAL AND PDGF-STIMULATED RAT VASCULAR SMOOTH MUSCLE CELLS THROUGH REGULATION AMPK/MTOR/P70S6K SIGNALING AXIS

Objective: Far-infrared (FIR) rays are invisible electromagnetic radiation with a wavelength of 3-1000 um, which elicits molecular vibrations in water and other organic molecules in cells and tissues, thereby FIR rays may have various biological effects. Aberrant proliferation of vascular smooth muscle cells (VSMCs) is associated with the development of diverse vascular diseases including atherosclerosis. Although FIR irradiation is reported to inhibit cell proliferation in various types of cells, effect of FIR irradiation on VSMC proliferation and the underlying mechanism remain elusive. Here, we investigated the molecular mechanism by which FIR irradiation inhibited VSMC proliferation. Design and method: We performed cell proliferation and viability assay, inhibitor studies, transfection of dominant negative (dn)-AMP-activated protein kinase (AMPK) alpha 1 gene, and western blot analyses. We also conducted confocal microscopic image analyses and ex vivo studies using isolated rat aortas. Results: FIR irradiation for 30 min decreased VSMC proliferation with no alteration in cell viability, which was accompanied by decreased phosphorylation of mammalian target of rapamycin (mTOR) at Ser2448 (p-mTOR-Ser2448) and p70 S6 kinase (p70S6K) at Thr389 (p-p70S6K-Thr389). Furthermore, FIR irradiation increased phosphorylation of AMP-activated protein kinase (AMPK) at Thr172 (p-AMPK-Thr172). Pre-treatment with compound C, a specific AMPK inhibitor, or ectopic expression of dn-AMPK alpha 1 gene, significantly reversed FIR irradiation-decreased VSMC proliferation, p-mTOR-Ser2448, and p-p70S6K-Thr389. However, hyperthermal stimulus (39 degrees) did not change VSMC proliferation and AMPK/mTOR/p70S6K phosphorylation. Similar to in vitro results, FIR irradiation increased p-AMPK-Thr172, and decreased p-mTOR-Ser2448 and p-p70S6K-Thr389 in isolated rat aortas. Finally, FIR irradiation attenuated platelet-derived growth factor (PDGF)-stimulated VSMC proliferation by increasing p-AMPK-Thr172, and decreasing p-mTOR-Ser2448 and p-p70S6K-Thr389 in PDGF-induced in vitro atherosclerosis model. Conclusions: We demonstrate that FIR irradiation decreases VSMC proliferation, at least in part, by regulating AMPK/mTOR/p70S6K signaling axis. These observations suggest that FIR ray therapy can be used to treat arterial narrowing diseases including atherosclerosis and in-stent restenosis.

Comparative Analysis of Active Ingredients and Potential Bioactivities of Essential Oils from Artemisia argyi and A. verlotorum.

Artemisia argyi H. Lév. and Vaniot is a variety of Chinese mugwort widely cultured in central China. A. verlotorum Lamotte, another variety of Chinese mugwort, has been used in the southern region of China since ancient times. Despite their similar uses in traditional medicine, little is known about the differences in their active ingredients and potential benefits. Herein, the chemical compositions of the essential oils (EOs) from both varieties were analyzed using chromatography-mass spectrometry (GC-MS). A series of databases, such as the Traditional Chinese Medicine Systems Pharmacology database (TCMSP), SuperPred database and R tool, were applied to build a networking of the EOs. Our results revealed significant differences in the chemical compositions of the two Artemisia EOs. However, we found that they shared similar ingredient-target-pathway networking with diverse bioactivities, such as neuroprotective, anti-cancer and anti-inflammatory. Furthermore, our protein connection networking analysis showed that transcription factor p65 (RELA), phosphatidylinositol 3-kinase regulatory subunit alpha (PIK3R1) and mitogen-activated protein kinase 1 (MAPK1) are crucial for the biological activity of Artemisia EOs. Our findings provided evidence for the use of A. verlotorum as Chinese mugwort in southern China.

Maternal glucagon-like peptide-1 is positively associated with fetal growth in pregnancies complicated with obesity.

Pregnant women with obesity are more likely to deliver infants who are large for gestational age (LGA). LGA is associated with increased perinatal morbidity and risk of developing metabolic disease later in life. However, the mechanisms underpinning fetal overgrowth remain to be fully established. Here, we identified maternal, placental, and fetal factors that are associated with fetal overgrowth in pregnant women with obesity. Maternal and umbilical cord plasma and placentas were collected from women with obesity delivering infants who were LGA (n=30) or appropriate for gestational age (AGA, n=21) at term. Maternal and umbilical cord plasma analytes were measured using multiplex sandwich assay and ELISA. Insulin/mechanistic target of rapamycin (mTOR) signaling activity was determined in placental homogenates. Amino acid transporter activity was measured in isolated syncytiotrophoblast microvillous membrane (MVM) and basal membrane (BM). Glucagon-like peptide-1 receptor (GLP-1R) protein expression and signaling were measured in cultured primary human trophoblast (PHT) cells. Maternal plasma glucagon-like peptide-1 (GLP-1) was higher in LGA pregnancies and positively correlated to birthweight. Umbilical cord plasma insulin, C-peptide, and GLP-1 were increased in obese-large for gestational age (OB-LGA) infants. LGA placentas were larger but showed no change in insulin/mTOR signaling or amino acid transport activity. GLP-1R protein was expressed in the MVM isolated from human placenta. GLP-1R activation stimulated protein kinase alpha (PKA), extracellular signal-regulated kinase-1 and-2 (ERK1/2), and mTOR pathways in PHT cells. Our results suggest elevated maternal GLP-1 may drive fetal overgrowth in obese pregnant women. We speculate that maternal GLP-1 acts as a novel regulator of fetal growth by promoting placental growth and function.

In vitro kinase assay reveals ADP-heptose-dependent ALPK1 autophosphorylation and altered kinase activity of disease-associated ALPK1 mutants

Alpha-protein kinase 1 (ALPK1) is a pathogen recognition receptor that detects ADP-heptose (ADPH), a lipopolysaccharide biosynthesis intermediate, recently described as a pathogen-associated molecular pattern in Gram-negative bacteria. ADPH binding to ALPK1 activates its kinase domain and triggers TIFA phosphorylation on threonine 9. This leads to the assembly of large TIFA oligomers called TIFAsomes, activation of NF-κB and pro-inflammatory gene expression. Furthermore, mutations in ALPK1 are associated with inflammatory syndromes and cancers. While this kinase is of increasing medical interest, its activity in infectious or non-infectious diseases remains poorly characterized. Here, we use a non-radioactive ALPK1 in vitro kinase assay based on the use of ATPγS and protein thiophosphorylation. We confirm that ALPK1 phosphorylates TIFA T9 and show that T2, T12 and T19 are also weakly phosphorylated by ALPK1. Interestingly, we find that ALPK1 itself is phosphorylated in response to ADPH recognition during Shigella flexneri and Helicobacter pylori infection and that disease-associated ALPK1 mutants exhibit altered kinase activity. In particular, T237M and V1092A mutations associated with ROSAH syndrome and spiradenoma/spiradenocarcinoma respectively, exhibit enhanced ADPH-induced kinase activity and constitutive assembly of TIFAsomes. Altogether, this study provides new insights into the ADPH sensing pathway and disease-associated ALPK1 mutants.

Constitutively activated AMPKα1 protects against skeletal aging in mice by promoting bone-derived IGF-1 secretion.

Senile osteoporosis is characterized by age-related bone loss and bone microarchitecture deterioration. However, little is known to date about the mechanism that maintains bone homeostasis during aging. In this study, we identify adenosine monophosphate-activated protein kinase alpha 1 (AMPKα1) as a critical factor regulating the senescence and lineage commitment of mesenchymal stem cells (MSCs). A phospho-mutant mouse model shows that constitutive AMPKα1 activation prevents age-related bone loss and promoted MSC osteogenic commitment with increased bone-derived insulin-like growth factor 1 (IGF-1) secretion. Mechanistically, upregulation of IGF-1 signalling by AMPKα1 depends on cAMP-response element binding protein (CREB)-mediated transcriptional regulation. Furthermore, the essential role of the AMPKα1/IGF-1/CREB axis in promoting aged MSC osteogenic potential is confirmed using three-dimensional (3D) culture systems. Taken together, these results can provide mechanistic insight into the protective effect of AMPKα1 against skeletal aging by promoting bone-derived IGF-1 secretion.

Muscle PARP1 inhibition extends lifespan through AMPKα PARylation and activation in Drosophila.

Poly(ADP-ribose) polymerase-1 (PARP1) has been reported to play an important role in longevity. Here, we showed that the knockdown of the PARP1 extended the lifespan of Drosophila, with particular emphasis on the skeletal muscle. The muscle-specific mutant Drosophila exhibited resistance to starvation and oxidative stress, as well as an increased ability to climb, with enhanced mitochondrial biogenesis and activity at an older age. Mechanistically, the inhibition of PARP1 increases the activity of AMP-activated protein kinase alpha (AMPKα) and mitochondrial turnover. PARP1 could interact with AMPKα and then regulate it via poly(ADP ribosyl)ation (PARylation) at residues E155 and E195. Double knockdown of PARP1 and AMPKα, specifically in muscle, could counteract the effects of PARP1 inhibition in Drosophila. Finally, we showed that increasing lifespan via maintaining mitochondrial network homeostasis required intact PTEN induced kinase 1 (PINK1). Taken together, these data indicate that the interplay between PARP1 and AMPKα can manipulate mitochondrial turnover, and be targeted to promote longevity.

FGF19 increases mitochondrial biogenesis and fusion in chondrocytes via the AMPKα-p38/MAPK pathway

Fibroblast growth factor 19 (FGF19) is recognized to play an essential role in cartilage development and physiology, and has emerged as a potential therapeutic target for skeletal metabolic diseases. However, FGF19-mediated cellular behavior in chondrocytes remains a big challenge. In the current study, we aimed to investigate the role of FGF19 on chondrocytes by characterizing mitochondrial biogenesis and fission–fusion dynamic equilibrium and exploring the underlying mechanism. We first found that FGF19 enhanced mitochondrial biogenesis in chondrocytes with the help of β Klotho (KLB), a vital accessory protein for assisting the binding of FGF19 to its receptor, and the enhanced biogenesis accompanied with a fusion of mitochondria, reflecting in the elongation of individual mitochondria and the up-regulation of mitochondrial fusion proteins. We then revealed that FGF19-mediated mitochondrial biogenesis and fusion required the binding of FGF19 to the membrane receptor, FGFR4, and the activation of AMP-activated protein kinase alpha (AMPKα)/peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α)/sirtuin 1 (SIRT1) axis. Finally, we demonstrated that FGF19-mediated mitochondrial biogenesis and fusion was mainly dependent on the activation of p-p38 signaling. Inhibition of p38 signaling largely reduced the high expression of AMPKα/PGC-1α/SIRT1 axis, decreased the up-regulation of mitochondrial fusion proteins and impaired the enhancement of mitochondrial network morphology in chondrocytes induced by FGF19. Taking together, our results indicate that FGF19 could increase mitochondrial biogenesis and fusion via AMPKα-p38/MAPK signaling, which enlarge the understanding of FGF19 on chondrocyte metabolism.1_TrhHGMYiD7TE3Fp_z9jvVideo

Anti-Inflammatory and Anti-Diabetic Activity of Ferruginan, a Natural Compound from Olea ferruginea

Inflammation is a complex response of the human organism and relates to the onset of various disorders including diabetes. The current research work aimed at investigating the anti-inflammatory and anti-diabetic effects of ferruginan, a compound isolated from Olea ferruginea. Its in vitro anti-inflammatory activity was determined by using the heat-induced hemolysis assay, while the anti-diabetic effect of the compound was studied by the yeast cell glucose uptake assay. Ferruginan exhibited a maximum of 71.82% inhibition of inflammation and also increased the uptake of glucose by yeast cells by up to 74.96% at the highest tested concentration (100 µM). Moreover, ferruginan inhibited α-amylase dose-dependently, by up to 75.45% at the same concentration. These results indicated that ferruginan possesses promising anti-inflammatory and anti-diabetic properties in vitro, even if at high concentrations. To provide preliminary hypotheses on the potentially multi-target mechanisms underlying such effects, docking analyses were performed on α-amylase and on various molecular targets involved in inflammation such as 5′-adenosine monophosphate-activated protein kinase (AMPK, PDB ID 3AQV), cyclooxygenase (COX-1, PDB ID 1EQG, and COX-2, 1CX2), and tumor necrosis factor alpha (TNF-α, PDB ID 2AZ5). The docking studies suggested that the compound may act on α-amylase, COX-2, and AMPK.

Dietary β-conglycinin induces intestinal enteritis and affects glycerophospholipid and arginine metabolism in mirror carp (Cyprinus carpio)

The use of soybean meal in aquafeed industry is partially limited by anti-nutritional factors such as β-conglycinin (β-CG). However, the effects of β-CG on mirror carp (Cyprinus carpio) growth performance and intestinal health has not been elucidated. This study investigated the effects of β-CG levels on growth performance, intestine immunity, and intestinal lipid and protein metabolism in mirror carp. Four hundred and fifty mirror carp (4.22 ± 0.03) g were fed a control (CON) diet containing fish meal as the protein source and four experimental diets containing β-CG at 40 (β-CG1), 80 (β-CG2), 120 (β-CG3), and 160 g/kg (β-CG4) replacing the fishmeal, respectively. Each treatment had 30 fish replicated three times and the feeding was done for six weeks. The results showed that weight gain, specific growth rate, survival rate, protein efficiency, feed conversion ratio, and condition factor were not affected by dietary β-CG (P > 0.05). Interestingly, the fish fed on the β-CG diets upregulated significantly the expression of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and eIF4E-binding protein (4E-BP) in the proximal intestine (PI) than those fed on the CON diet (P < 0.05). The fish fed on the β-CG2 diet decreased significantly the expression of transforming growth factor beta 1 (TGFβ1) in the PI compared to those fed on the CON diet. The fish fed on the β-CG diets downregulated significantly the expression of target of rapamycin (TOR) in the PI than those fed on the CON diet. The fish fed on β-CG diets downregulated significantly the expression of AMP-activated protein kinase alpha (AMPK), acetyl-CoA carboxylase (ACC), TOR in the mid intestine (MI) while, claudin11 gene was significantly increased (P < 0.05). In the distal intestine (DI), feeding the fish on the β-CG diets downregulated significantly the expression of AMPK and ACC genes, while increased the expression TNF-α, IL-1β and claudin11 (P < 0.05). Feeding the fish with the β-CG diets mostly altered glycerophospholipid metabolism and arginine biosynthesis in intestinal mucosa. These results suggest that dietary β-CG induces enteritis in different intestinal segments and changes glycerophospholipid metabolism and arginine biosynthesis pathways. Fish farmers using soybean meal in the diets should process the ingredients to reduce β-CG concentration before use.