Monophosphate-activated Protein Kinase Research Articles

Loss of miR-144/451 alleviates β-thalassemia by stimulating ULK1-mediated autophagy of free α-globin

AbstractMost cells can eliminate unstable or misfolded proteins through quality control mechanisms. In the inherited red blood cell disorder β-thalassemia, mutations in the β-globin gene (HBB) lead to a reduction in the corresponding protein and the accumulation of cytotoxic free α-globin, which causes maturation arrest and apoptosis of erythroid precursors and reductions in the lifespan of circulating red blood cells. We showed previously that excess α-globin is eliminated by Unc-51–like autophagy activating kinase 1 (ULK1)-dependent autophagy and that stimulating this pathway by systemic mammalian target of rapamycin complex 1 (mTORC1) inhibition alleviates β-thalassemia pathologies. We show here that disrupting the bicistronic microRNA gene miR-144/451 alleviates β-thalassemia by reducing mTORC1 activity and stimulating ULK1-mediated autophagy of free α-globin through 2 mechanisms. Loss of miR-451 upregulated its target messenger RNA, Cab39, which encodes a cofactor for LKB1, a serine-threonine kinase that phosphorylates and activates the central metabolic sensor adenosine monophosphate–activated protein kinase (AMPK). The resultant enhancement of LKB1 activity stimulated AMPK and its downstream effects, including repression of mTORC1 and direct activation of ULK1. In addition, loss of miR-144/451 inhibited the expression of erythroblast transferrin receptor 1, causing intracellular iron restriction, which has been shown to inhibit mTORC1, reduce free α-globin precipitates, and improve hematological indices in β-thalassemia. The beneficial effects of miR-144/451 loss in β-thalassemia were inhibited by the disruption of Cab39 or Ulk1 genes. Together, our findings link the severity of β-thalassemia to a highly expressed erythroid microRNA locus and a fundamental, metabolically regulated protein quality control pathway that is amenable to therapeutic manipulation.

AMPK-endoplasmic reticulum stress axis contributes to lipopolysaccharide-caused mitochondrial dysfunction by regulating mitochondria-associated membrane function in bovine hepatocytes

Mitochondrial homeostasis is closely associated with cellular homeostasis process, whereas mitochondrial dysfunction contributes to apoptosis and mitophagy. Hence, analyzing the mechanism of lipopolysaccharide (LPS)-caused mitochondrial damage is necessary to understand how cellular homeostasis is maintained in bovine hepatocytes. Mitochondria-associated membranes (MAM), a connection between endoplasmic reticulum (ER) and mitochondria, is important to control mitochondrial function. To investigate the underlying mechanisms of the LPS-caused mitochondrial dysfunction, hepatocytes isolated from dairy cows at ∼160 d in milk (DIM) were pretreated with the specific inhibitors of adenosine 5'-monophosphate-activated protein kinase (AMPK), ER stress, RNA-activated protein kinase-like ER kinase (PERK), inositol-requiring enzyme 1α (IRE1α), c-Jun N-terminal kinase, and autophagy followed by a 12 I1/4g/mL LPS treatment. The results showed that inhibiting ER stress with 4-phenylbutyric acid decreased the levels of autophagy and mitochondrial damage with AMPK inactivation in LPS-treated hepatocytes. The AMPK inhibitor compound C pretreatment alleviated LPS-induced ER stress, autophagy and mitochondrial dysfunction by regulating the expression of MAM-related genes, such as mitofusin 2 (MFN2), PERK, and IRE1α. Moreover, inhibiting PERK and IRE1α mitigated autophagy and mitochondrial dynamic disruption by regulating the MAM function. Additionally, blocking c-Jun N-terminal kinase, the downstream sensor of IRE1α, could reduce the levels of autophagy and apoptosis and restore the balance of mitochondrial fusion and fission by modulating the B cell leukemia 2 (BCL-2)/BCL-2 interacting protein 1 (BECLIN1) complex in the LPS-treated bovine hepatocytes. Furthermore, autophagy blockage with chloroquine could intervene in LPS-caused apoptosis to restore mitochondrial function. Collectively, these findings suggest that the AMPK-ER stress axis is involved in the LPS-caused mitochondrial dysfunction by mediating the MAM activity in bovine hepatocytes.

Clean-DM1, a Korean Polyherbal Formula, Improves High Fat Diet-Induced Diabetic Symptoms in Mice by Regulating IRS/PI3K/AKT and AMPK Expressions in Pancreas and Liver Tissues.

To investigate the effects of Clean-DM1 (C-DM1), a polyherbal formulation of Radix Scrophulariae, Radix Astragali, Rhizoma Atractylodis, and Radix Salviae Miltiorrhizae, on high-fat diet (HFD)-induced diabetes mice. The information about active components of C-DM1 extract and molecular mechanism was obtained from network pharmacology analysis. Main compounds of C-DM1 extract by high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis were conducted for quality control. For in vivo study, mice were induced diabetes by HFD for 12 weeks. The mice in the normal group (Nor) were maintained with a regular diet and treated with saline by gavage. The HFD model mice were randomly divided into 3 groups, including a HFD diabetic model group, a C-DM1 extract-administered group (C-DM1, 500 mg/kg), and metformin-administered groups (Met, 500 mg/kg), 8 mice in each group. Food intake, body weight (BW), and fasting blood glucose (FBG) levels were recorded weekly for 4 weeks. After 4 weeks of treatment, alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood glucose, low-density lipoprotein cholesterol (LDL-C) were determined using an automated clinical chemistry analyzer, and homeostatic model for assessing insulin resistance (HOMA-IR) levels and oral glucose tolerance test (OGTT) were detected. The histopathological changes of liver and pancreatic tissues were observed by hematoxylin-eosin staining. Insulin receptor substrate (IRS)/phosphatidylinositol 3 kinase (PI3K)/ protein kinase B (AKT) and adenosine 5'-monophosphate-activated protein kinase (AMPK) expressions in liver and pancreas tissues were detected by Western blot analysis. HPLC-MS identified dihydroisotanshinone, dihydroisotanshinone I, cryptotanshinone, harpagoside, and atractyloside A in C-DM1 extract. The administration of C-DM1 extract significantly decreased body weight, calorie intake, and the levels of blood glucose and insulin in the diabetic mice (P<0.05 or P<0.01). The C-DM1 extract administration improved the impaired glucose tolerance and insulin resistance in the diabetic mice and significantly decreased the levels of LDL-C, ALT and AST (P<0.01). The C-DM1 extract inhibited the histopathological changes of fatty liver and hyperplasia of pancreatic islets in the diabetic mice. The C-DM1 extract significantly increased the phosphorylation of IRS, AKT, and AMPK and the expression of PI3K in pancreas and liver tissues (P<0.05 or P<0.01), which was consistent with the analysis results of network pharmacology. C-DM1 extract improved diabetes symptoms in long-term HFD-induced mice by regulation of IRS/PI3K/AKT and AMPK expressions in pancreas and liver tissues, suggesting that C-DM1 formulation may help prevent the progression of T2DM.

Metabolic Intervention Liposome Boosted Lung Cancer Radio-Immunotherapy via Hypoxia Amelioration and PD-L1 Restraint.

At present, radiotherapy (RT) still acquires limited success in clinical due to the lessened DNA damage under hypoxia and acquired immune tolerance owing to the amplified programmed death ligand-1 (PD-L1) expression. Incredibly, intracellular PD-L1 expression depression is proven to better sensitize RT by inhibiting DNA damage repair. However, the disability of the clinically used antibodies in disrupting the extracellular PD-L1function still limits the effectiveness of radio-immunotherapy. Therefore, better PD-L1 regulation strategies are still urgently needed to better sensitize radio-immunotherapy. Hence, for this purpose, TPP-LND is synthesized by linking mitochondrial-targeted triphenylphosphine cations (TPP+ ) to the antineoplastic agent lonidamine (LND), which significantly reduces the dose needed for LND to induce effective oxidative phosphorylation inhibition (2 vs 300µM). Then, TPP-LND is wrapped with liposomes to form TPP-LND@Lip nanoparticles. By doing this, TPP-LND@Lip nanoparticles can sensitize RT by reversing the hypoxic microenvironment of tumors to generate more DNA damage and reducing the expression of PD-L1 via enhancing the adenosine 5'-monophosphate-activated protein kinase activation.As expected, these well-designed economical TPP-LND@Lip nanoparticles are more effective than conventional anti-PD-L1 antibodies to some extent.

Quantitative analysis and hepatoprotective mechanism of Cistanche deserticola Y. C. Ma against alcohol-induced liver injury in mice

Cistanche deserticola Y. C. Ma (CD), known as “desert ginseng”, has been found to have hepatoprotective effect. This research aimed to investigate the quality control and its alleviating effect on alcoholic liver injury in mice. In this study, for the first time, a sensitive and efficient ultra-high-performance liquid chromatography with quadrupole ion-trap mass spectrometry (UPLC-Q-TRAP/MS) method was developed to rapidly characterize nine representative phenylethanoid glycosides (PhGs) in the CD extract within 14 min, offering a reference for the quality control standard of this plant. In addition, we found that the CD extract significantly inhibited the weight loss, decreased the liver index, and attenuated excessive lipid deposition, inflammatory and oxidative stress in the mice liver. With the help of the high-throughput lipidomics technique, we discovered that CD markedly reversed 17 lipid metabolites and their involved linoleic acid, arachidonic acid and glycerophospholipid metabolic pathways. As these metabolites are mainly associated with lipid metabolism and liver damage, we further used molecular biological tests to found that CD could regulate the upstream genes and proteins of the lipid metabolism pathway, including adenosine 5′-monophosphate-activated protein kinase (AMPK), sterol regulatory element binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and peroxidase proliferators activate receptors α (PPARα). In conclusion, this study elucidates the modulatory effects of CD on lipid metabolism disorders in alcoholic fatty liver from holistic system and provides a reference for further research and development of CD as a therapeutic agent.

Punicalagin inhibits hepatic lipid deposition in obese mice via AMPK/ACC pathway

Hepatic lipid deposition is one of the basic manifestations of obesity, and nowadays pharmacological treatment is the most important tool. Punicalagin(PU), a polyphenol derived from pomegranate peel, is a potential anti-obesity substance. In this study, 60 C57BL/6J mice were randomly divided into a normal group and a model group. After establishing a model of simple obesity with a high-fat diet for 12 weeks, the successfully established rat models of obesity were then regrouped into a model group, an orlistat group, a PU low-dose group, a PU medium-dose group, and a PU high-dose group. The normal group was kept on routine diet and other groups continued to feed the high-fat diet. The body weight and food intake were measured and recorded weekly. After 8 weeks, the levels of the four lipids in the serum of each group of mice were determined by an automatic biochemical instrument. Oral glucose tole-rance and intraperitoneal insulin sensitivity were tested. Hemoxylin-eosin(HE) staining was applied to observe the hepatic and adipose tissues. The mRNA expression levels of peroxisome proliferators-activated receptor γ(PPARγ) and C/EBPα were determined by real-time quantitative polymerase chain reaction(Q-PCR), and the mRNA and protein expression levels of adenosine 5'-monophosphate-activated protein kinase(AMPK), anterior cingulate cortex(ACC), and carnitine palmitoyltransferase 1A(CPT1A) were determined by Western blot. Finally, the body mass, Lee's index, serum total glyceride(TG), serum total cholesterol(TC), and low-density lipoprotein cholesterol(LDL-C) levels were significantly higher and high-density lipoprotein cholesterol(HDL-C) levels were significantly lower in the model group as compared with the normal group. The fat deposition in the liver was significantly increased. The mRNA expression levels of hepatic PPARγ and C/EBPα and the protein expression level of ACC were increased, while the mRNA and protein expression levels of CPT-1α(CPT1A) and AMPK were decreased. After PU treatment, the above indexes of obese mice were reversed. In conclusion, PU can decrease the body weight of obese mice and control their food intake. It also plays a role in the regulation of lipid metabolism and glycometabolism metabolism, which can significantly improve hepatic fat deposition. Mechanistically, PU may regulate liver lipid deposition in obese mice by down-regulating lipid synthesis and up-regulating lipolysis through activation of the AMPK/ACC pathway.

The Anti-hyperuricemia and Anti-inflammatory Effects of Atractylodes Macrocephala in Hyperuricemia and Gouty Arthritis Rat Models.

Atractylodes macrocephala is a traditional Chinese medicine with a variety of pharmacological activities. This study aimed to evaluate its anti-hyperuricemia and antiinflammatory effects on gout, and to preliminarily explore its mechanism. The hyperuricemia rat model was established by intraperitoneal injection of oteracil potassium and intragastric gavage of yeast powder solution. And the acute gouty arthritis (GA) model was established by injecting monosodium urate (MSU) suspension. In the study of the antihyperuricemia effect of Atractylodes macrocephala, the healthy male Sprague-Dawley rats were randomly divided into the blank group, hyperuricemia group allopurinol group as well as low, moderate and high dose groups of Atractylodes macrocephala decoction (N=8 rats in each group). Serum, liver and kidney tissue samples were collected from each group. Serum uric acid (UA), adenosine deaminase (ADA) and xanthine oxidase (XOD) levels in each group were detected by enzyme-linked immunosorbent assay (ELISA). Protein levels of ADA and XOD in liver tissues were detected by Western blot, and renal histological changes were observed by Hematoxylin-eosin (H&E) and Masson staining. In order to investigate the anti-inflammatory effect of Atractylodes macrocephala, the healthy male Sprague-Dawley rats were randomly divided into the blank group, GA group, colchicine group, high, moderate and low dose groups of Atractylodes macrocephala decoction (N=8 rats in each group), and serum and synovial tissue of each group were collected. Then the level of serum interleukin (IL)-1β and tumor necrosis factor (TNF)-α was observed by ELISA, and the histological changes of synovial tissue were observed by H&E staining. Besides, the expression of adenosine monophosphate- activated protein kinase (AMPK) /silent information regulator (SIRT) 1/ nuclear factor kappa B (NF-κB) protein in synovial tissue was observed by Western blot and immunohistochemistry. The markers of M1 and M2 macrophages, inducible nitric oxide synthase (iNOS) and arginase-1 (ARG1) were observed by Western blot and immunofluorescence. Atractylodes macrocephala could reduce the production of UA by inhibiting the level of ADA and XOD, and could improve renal injury and fibrosis. In addition, Atractylodes macrophages could reduce the levels of IL-1β and TNF-α, activate AMPK/SIRT1 signaling pathway, and inhibit the activation of NF-κB and the polarization of macrophages to a pro-inflammatory phenotype. Atractylodes macrocephala shows good anti-hyperuricemic and anti-inflammatory effects, and its anti-inflammation pharmacological activity may be related to the inhibition of M1 macrophage polarization and NF-κB activation through activating AMPK/SIRT1.

Acadesine supplementation in a soybean oil-based diet remodels hepatic lipid and glucose metabolism in juvenile large yellow croaker (Larimichthys crocea)

Dietary high soybean oil (SO) inclusion leads to excessive hepatic lipid accumulation and metabolism disorder in fish species. This study was conducted to investigate the effects of adenosine 5’-monophosphate-activated protein kinase (AMPK) pathway activation by acadesine (AICAR) on hepatic histology and metabolism-related gene expression of juvenile large yellow croakers (Larimichthys crocea) fed with SO-based diet. In this study, fish (initial body weight 3.89 ± 0.02 g) were fed fish oil (FO)-based, SO, or SOA (SO diet supplemented with 100 mg kg−1 AICAR) diets with three replicates of each treatment for 70 days. In general, the replacement of dietary FO with SO led to excessive hepatic lipid accumulation and a glucose metabolism disorder. Histological sections and biochemical analysis of hepatic tissue consistently revealed that AICAR supplementation could partly ameliorate SO-induced excessive hepatic lipid accumulation, probably by suppressing the expression of genes related to fatty acid uptake and lipogenesis while enhancing the expression of lipolysis-related genes. Nevertheless, AICAR regulated lipid metabolism in muscle tissue in an inverse pattern to that in hepatic tissue, indicating that muscle tissue could attempt to mitigate lipid accumulation by improving lipolysis in response to the dietary inclusion of SO. Dietary AICAR partly improved glucose metabolism by reducing the expression of genes related to gluconeogenesis in hepatic tissue while increasing the expression of genes related to glucose uptake and glycolysis in muscle tissue. Collectively, dietary AICAR mitigated excessive hepatic lipid accumulation and glucose metabolism disorder. The amelioration of hepatic lipid accumulation by AICAR is likely caused by increasing lipid catabolism and decreasing lipid anabolism. The improved glucose metabolism by AICAR may be ascribed to decreased hepatic gluconeogenesis, as well as increased muscle glucose uptake and utilization.

Immunostimulatory and anti‑obesity activities of Adenocaulonhimalaicum leaves in RAW264.7 and 3T3‑L1 cells.

The present study investigated the immunostimulatory activity and anti-obesity activity of Adenocaulon himalaicum leaf extracts (AHL) in RAW264.7 cells and 3T3-L1 cells. AHL increased the production of immunostimulatory factors, such as NO, inducible nitric oxide synthase (iNOS), IL-1β, IL-6 and TNF-α and activated the phagocytotic activity in RAW264.7 cells. Inhibition of Toll-like receptor 4 (TLR4) attenuated the AHL-mediated production of immunostimulatory factors and activation of phagocytic activity in RAW264.7 cells. Inhibition of p38 and JNK blocked the AHL-mediated production of immunostimulatory factors, whereas inhibition of TLR4 suppressed the AHL-mediated phosphorylation of p38 and JNK. Additionally, AHL blocked the lipid accumulation in 3T3-L1 cells. AHL downregulated proliferator-activated receptor γ, CCAAT enhancer binding protein α and perilipin-1 levels, while upregulating adipose triglyceride lipase, phosphorylated (p-)hormone-sensitive lipase, p-adenosine monophosphate activated protein kinase, uncoupling protein 1, peroxisome-proliferator-activated receptor-γ coactivator-1 α and PR domain containing 16 levels in 3T3-L1 cells. These findings suggested that AHL may exert immunostimulatory activity through macrophages via TLR4-mediated activation of p38 and JNK and anti-obesity activity by blocking lipid accumulation via the inhibition of adipogenesis and induction of lipolysis and browning of white adipocytes.

Increased RTN3 phenocopies nonalcoholic fatty liver disease by inhibiting the AMPK-IDH2 pathway.

Reticulon 3 (RTN3), an endoplasmic reticulum protein, is crucial in neurodegenerative and kidney diseases. However, the role of RTN3 in liver tissues has not been described. Here, we employed public datasets, patients, and several animal models to explore the role of RTN3 in nonalcoholic fatty liver disease (NAFLD). The underlying mechanisms were studied in primary hepatocytes and L02 cells in vitro. We found an increased expression of RTN3 in NAFLD patients, high-fat diet mice, and oxidized low-density lipoprotein-treated L02 cells. The RTN3 transgenic mice exhibited the phenotypes of fatty liver and lipid accumulation. Single-cell RNA sequencing analysis indicated that increased RTN3 might induce mitochondrial dysfunction. We further showed this in primary hepatocytes, the L02 cell line, and the Caenorhabditis elegans strain. Mechanistically, RTN3 regulated these events through its interactions with glucose-regulated protein 78 (GRP78), which further inhibited the adenosine 5 monophosphate-activated protein kinase (AMPK)-isocitrate dehydrogenase 2 (IDH2) pathway. In the end, knockout of RTN3 relieved fatty liver and mitochondrial dysfunction. Our study indicated that RTN3 was important in NAFLD and lipid catabolism and that an increase in RTN3 in the liver might be a risk factor for nonalcoholic steatohepatitis and NAFLD.

Dietary tryptophan supplementation enhances mitochondrial function and reduces pyroptosis in the spleen and thymus of piglets after lipopolysaccharide challenge.

The thymus and spleen, the main reservoirs for T lymphocytes, modulate the innate immune response. Oxidative stress, excessive inflammation and abnormal pyroptosis can cause dysfunction of these organs. This study aimed to examine whether tryptophan supplementation can improve growth performance and mitochondrial function via the adenosine 5'-monophosphate-activated protein kinase (AMPK)/sirtuin1 (Sirt1)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) signalling pathway and decrease pyroptosis via the nucleotidebinding oligomerisation domain-like receptor protein 3 (NLRP3)/caspase-1/gasderminD (GSDMD) signalling pathway in the spleen and thymus of piglets after lipopolysaccharide (LPS) challenge. Eighteen weaned piglets were allotted to three treatment groups: non-challenged control, LPS-challenged control and LPS+0.2% tryptophan. On day 35, the pigs in the LPS and LPS+0.2% tryptophan groups were injected with 100μg/kg BW LPS, whereas those in the control group were administered with sterile saline. At 4h postchallenge, the weaned piglets were sacrificed, and their thymuses and spleens were collected. Results showed that tryptophan enhanced growth performance and antioxidant status by increasing catalase, glutathione peroxidase and total superoxide dismutase activities and decreasing malondialdehyde and reactive oxygen species contents. Tryptophan also reduced the mRNA levels of proinflammatory cytokine genes and enhanced mitochondrial function by increasing the mRNA levels of mitochondrial transcription factor A, nuclear respiratory factor-1, mitochondria transcription factor B1, AMPKα1, AMPKα2, Sirt1 and PGC1α and the protein expression of phosphorylated AMPK, Sirt1 and PGC1α. It also reduced pyroptosis by decreasing the mRNA levels of NLRP3, apoptosis-associated speck-like protein containing CARD, caspase-1 and GSDMD and the protein expression of NLRP3, caspase-1 and GSDMD. These results indicate that tryptophan supplementation enhances growth performance and mitochondrial function via the AMPK/Sirt1/PGC1α signalling pathway and decreases pyroptosis via the NLRP3/caspase-1/GSDMD signalling pathway in the spleen and thymus of LPS-challenged piglets.

Lead intoxication-induced exosomes promote autophagy and apoptosis in renal proximal tubule cells by activating the adenosine 5'-monophosphate-activated protein kinase signaling.

Lead (Pb) intoxication is known to damage the proximal tubules of kidney. Autophagy and apoptosis have been shown to be involved in a variety of renal injuries, but the underlying mechanisms remain largely unknown. In this study, we constructed a mice model of Pb intoxication and validated it against lead concentrations in blood and urine. Electron microscopy revealed that Pb promoted the accumulation of autophagosomes. Subsequent immunofluorescence and western blotting revealed that Pb intoxication suppressed the autophagic flux. Next, exosomes were isolated and extracted through ultracentrifugation, and were further identified by diameter analysis and marker detection. We also demonstrated that autophagy and apoptosis were enhanced in renal cells with exosomes of Pb expose. Furthermore, the specific mechanisms were explored by RNA sequencing and it was found that several targeted genes regulated by differential exosomal miRNAs and lncRNAs. Target genes accumulated in several signaling pathways, especially the adenosine 5'-monophosphate-activated protein kinase(AMPK) signaling. We found that Pb intoxication-induced exosomes activated the AMPK signaling in renal proximal tubule cells. Furthermore, autophagy and apoptosis assays showed that GSK-690693, an AMPK inhibitor, significantly alleviated exosome-induced renal injuries by Pb intoxication. In conclusion, Pb-mediated exosome-induced autophagy and apoptosis via activating the AMPK signaling contributing to Pb-induced nephrotoxicity in renal cells.

Imidazo[1,2-a]pyridine Derivatives as AMPK Activators: Synthesis, Structure-Activity Relationships, and Regulation of Reactive Oxygen Species in Renal Fibroblasts.

Adenosine 5'-monophosphate activated protein kinase (AMPK) has emerged as a promising target for the discovery of drugs to treat diabetic nephropathy (DN). Herein, a series of imidazo[1,2-a]pyridines were designed and synthesized. Among them, the active compound (EC50 =11.0 nM) showed good enzyme activation and molecular docking results showed hydrogen bonding interactions with the key amino acids Asn111 and Lys29 in the active site. Meanwhile, further cellular level experiments revealed that it could reduce reactive oxygen species (ROS) levels in NRK-49F cells induced by high glucose, and Western Blot experiments also demonstrate that it can increase the levels of p-AMPK and p-ACC and decrease the levels of TGF-β1. The results of this study extend the structural types of AMPK activators and provide novel lead compounds for the subsequent development.

Black Rice Anthocyanidins Regulates Gut Microbiota and Alleviates Related Symptoms through PI3K/AKT Pathway in Type 2 Diabetic Rats

Black rice anthocyanins (BRAs) have extremely high nutritional value and health care effects. This study investigated the intervention effect of BRAs on type 2 diabetes mellitus (T2DM) and the regulation effect on intestinal microbiota imbalance in T2DM rats. This study established successfully a T2DM model in a high-fat and high-glucose diet combined with streptozotocin (STZ). BRAs intervention reduced significantly the fasting blood glucose level of T2DM rats, improved the glucose tolerance of rats, reduced the blood lipid level and inflammation state, and repaired liver, oxidative stress, and other injuries. In addition, BRAs’s intervention enhanced the expression of phosphoinositol 3-kinase (PI3K)/protein kinase B (AKT), activated the expression of adenosine 5’-monophosphate-activated protein kinase(AMPK), and the downstream acetyl-CoA carboxylase (ACC) and carnitine palmitoyl transferase (CPT1) in the liver. 16S rRNA sequencing showed that BRAs significantly decreased the abundances of Bifidobacterium and Clostridiaceae_Clostridium, and promoted the abundances of Akkermansia and Lactobacillus. Accelerate the recovery of gut microbiota diversity. BRAs play an antidiabetic role by regulating the PI3K/AKT signaling pathway and intestinal microbiota in T2MD rats.

Does Lactate-Guided Threshold Interval Training within a High-Volume Low-Intensity Approach Represent the "Next Step" in the Evolution of Distance Running Training?

The aim of the present study was to describe a novel training model based on lactate-guided threshold interval training (LGTIT) within a high-volume, low-intensity approach, which characterizes the training pattern in some world-class middle- and long-distance runners and to review the potential physiological mechanisms explaining its effectiveness. This training model consists of performing three to four LGTIT sessions and one VO2max intensity session weekly. In addition, low intensity running is performed up to an overall volume of 150-180 km/week. During LGTIT sessions, the training pace is dictated by a blood lactate concentration target (i.e., internal rather than external training load), typically ranging from 2 to 4.5 mmol·L-1, measured every one to three repetitions. That intensity may allow for a more rapid recovery through a lower central and peripheral fatigue between high-intensity sessions compared with that of greater intensities and, therefore, a greater weekly volume of these specific workouts. The interval character of LGTIT allows for the achievement of high absolute training speeds and, thus, maximizing the number of motor units recruited, despite a relatively low metabolic intensity (i.e., threshold zone). This model may increase the mitochondrial proliferation through the optimization of both calcium and adenosine monophosphate activated protein kinase (AMPK) signaling pathways.

Effect and mechanisms of dexmedetomidine combined with macrophage migration inhibitory factor inhibition on the expression of inflammatory factors and AMPK in mice.

Reperfusion after acute myocardial infarction can cause ischemia/reperfusion (I/R) injury, which not only impedes restoration of the functions of tissues and organs but may also aggravate structural tissue and organ damage and dysfunction, worsening the patient's condition. Thus, the mechanisms that underpin myocardial I/R injury need to be better understood. We aimed to examine the effect of dexmedetomidine on macrophage migration inhibitory factor (MIF) in cardiomyocytes from mice with myocardial I/R injury and to explore the mechanistic role of adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling in this process. Myocardial I/R injury was induced in mice. The expression of serum inflammatory factors, reactive oxygen species (ROS), adenosine triphosphate (ATP), and AMPK pathway-related proteins, as well as myocardial tissue structure and cell apoptosis rate, were compared between mice with I/R injury only; mice with I/R injury treated with dexmedetomidine, ISO-1 (MIF inhibitor), or both; and sham-operated mice. Dexmedetomidine reduced serum interleukin (IL)-6 and tumor necrosis factor-α concentrations and increased IL-10 concentration in mice with I/R injury. Moreover, dexmedetomidine reduced myocardial tissue ROS content and apoptosis rate and increased ATP content and MIF expression. MIF inhibition using ISO-1 reversed the protective effect of dexmedetomidine on myocardial I/R injury and reduced AMPK phosphorylation. Dexmedetomidine reduces the inflammatory response in mice with I/R injury and improves adverse symptoms, and its mechanism of action may be related to the MIF-AMPK pathway.

Amniotic fluid stem cell attenuated necrotizing enterocolitis progression by promoting Rspo3/AMPKα axis

R-spondin 3 (Rspo3) is involved in various cellular processes. The alteration of Rspo3 participates in the differentiation of intestinal epithelial cells which are the crucial effector cells during necrotizing enterocolitis (NEC) development. Amniotic fluid stem cells (AFSCs) were recently indicated as a potential approach for NEC therapy. This study aimed to illustrate the regulatory role and mechanism of Rspo3 in the pathogenesis of NEC and whether AFSCs therapy would impact NEC by mediating Rspo3. First, the alteration of Rspo3 was investigated in the serum and tissues of NEC patients, and an in vitro cell model induced by LPS. A gain-of-function assay was conducted to explore the function of Rspo3 in NEC. Through the analysis of adenosine 5‘-monophosphate-activated protein kinase α (AMPKα) activation, the mechanism of Rspo3-mediated NEC progression was demonstrated. Finally, AFSCs were used to coculture human intestinal epithelial cells (HIECs) and the impacts on NEC development were also explored. The results found that Rspo3 was dramatically depressed during NEC progression and reversing Rspo3 expression ameliorated LPS-induced injury, inflammation, oxidative stress and tight junction dysregulation in HIECs. Besides, Rspo3 overexpression reversed AMPKα inactivation induced by NEC and an AMPKα inhibitor, Compound C, blocked the effect of Rspo3 overexpression on NEC. AFSCs treatment was beneficial for NEC therapy by restoring Rspo3 expression which was counteracted by exosome inhibitor. Generally, AFSCs attenuated NEC progression by promoting the Rspo3/AMPKα axis which might exert via the secretion of exosomes. Our conclusions might be valuable for NEC diagnosis and therapy.

Berberine Ameliorates Abnormal Lipid Metabolism via the Adenosine Monophosphate–Activated Protein Kinase/Sirtuin 1 Pathway in Alcohol-Related Liver Disease

Alcoholic fatty liver disease (AFLD) is an early stage of alcohol-related liver disease characterized by abnormal lipid metabolism in hepatocytes. To date, to our knowledge, there have been no effective strategies for preventing or treating alcohol-related liver disease besides alcohol abstinence. Berberine (BBR) is the main bioactive ingredient extracted from traditional Chinese medicines, such as Coptis and Scutellaria, which protect liver function and relieve liver steatosis. However, the potential role of BBR in AFLD remains unclear. Therefore, this study investigated the protective effects of BBR against Gao-binge model–induced AFLD in 6- to 8-week-old C57BL/6J male mice in vivo and ethyl alcohol (EtOH)-induced alpha mouse liver 12 (AML-12) cells in vitro. The results showed that BBR (200 mg/kg) attenuated alcoholic liver injury and suppressed lipid accumulation and metabolism disorders in vivo. Consistently, BBR effectively inhibited the expression of sterol regulatory element-binding transcription factor 1C, sterol regulatory element-binding transcription factor 2, fatty acid synthase, and 3-hydroxy-3-methylglutaryl-CoenzymeA reductase in EtOH-stimulated AML-12 cells in vitro and promoted the expression of sirtuin 1 (SIRT1) in EtOH-fed mice and EtOH-treated AML-12 cells. Furthermore, SIRT1 silencing attenuated the hepatic steatosis alleviation potential of BBR treatment. Mechanistically, molecular docking revealed the binding effect of BBR and adenosine monophosphate–activated protein kinase (AMPK). The results of further studies showed that a decrease in AMPK activity was accompanied by a significant inhibition of SIRT1 expression. SIRT1 silencing attenuated the protective effect of BBR, whereas the inhibition of its expression had no apparent effect on AMPK phosphorylation, suggesting that SIRT1 acts downstream of AMPK in AFLD. Collectively, BBR ameliorated abnormal lipid metabolism and alleviated EtOH-induced liver injury via the AMPK/SIRT1 pathway in AFLD mice.

AMPK activator decelerates osteoarthritis development by inhibition of β-catenin signaling in chondrocytes.

Osteoarthritis (OA) is a common degenerative joint disease with significant negative impact on the quality of life. It has been reported that abnormal upregulation of β-catenin signaling could lead to OA development; however, the upstream regulatory mechanisms of β-catenin signaling have not been determined. Primary rat chondrocytes and ATDC5 chondrocyte cell line were stimulated with AKT2 and treated with or without metformin, an adenosine 5'-monophosphate-activated protein kinase (AMPK) activator. Westerrn blot analysis, luciferase reporter assay and immunofluorescent (IF) staining were performed to examine changes in β-cateninS552 phosphorylation and β-catenin nuclear translocation in ATDC5 cells and in primary chondrocytes. We found that metformin inhibited β-cateninS552 phosphorylation in ATDC5 cells and in primary chondrocytes in a time-dependent manner. Metformin inhibited β-catenin nuclear translocation and β-catenin reporter activity. In addition, metformin also attenuated the expression of β-catenin downstream target genes. We also demonstrated that metformin inhibited β-cateninS552 phosphorylation in articular cartilage in mice. These findings suggest that metformin may exert its chondro-protective effect at least in part through the inhibition of β-catenin signaling in chondrocytes. This study demonstrated the interaction between AMPK and β-catenin signaling in chondrocytes and defined novel molecular targets for the treatment of OA disease.

Knockdown of 11β-hydroxysteroid dehydrogenase type 1 alleviates LPS-induced myocardial dysfunction through the AMPK/SIRT1/PGC-1α pathway.

Sepsis-induced myocardial dysfunction is primarily accompanied by severe sepsis, which is associated with high morbidity and mortality. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), encoded by Hsd11b1, is a reductase that can convert inactive cortisone into metabolically active cortisol. The role of 11β-HSD1 in sepsis-induced myocardial dysfunction remains poorly understood. The current study aims to investigate the effects of 11β-HSD1 on a lipopolysaccharide (LPS)-induced mouse model. LPS (10 mg/kg) was administered to wild-type C57BL/6J mice and 11β-HSD1 global knockout mice. Cardiac function was assessed by echocardiography. Transmission electron microscopy and immunohistochemical staining were performed to analyze myocardial mitochondrial injury and histological changes. The levels of reactive oxygen species and biomarkers of oxidative stress were determined. Polymerase chain reaction analysis, Western blotting, and immunofluorescent staining were employed to determine the expression of related genes and proteins. To investigate the role of 11β-HSD1 in sepsis-induced myocardial dysfunction, LPS was used to induce lentivirus-infected neonatal rat ventricular cardiomyocytes. Knockdown of 11β-HSD1 alleviated LPS-induced myocardial mitochondrial injury, oxidative stress, and inflammation, along with an improved myocardial function. Furthermore, the depletion of 11β-HSD1 promoted the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK), peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α), and silent information regulator 1 (SIRT1) protein levels both in vivo and in vitro. The suppression of 11β-HSD1 may be a viable strategy to improve cardiac function against endotoxemia challenges.