The Usnic Acid Analogue 4-FPBUA Enhances the Blood-Brain Barrier Function and Induces Autophagy in Alzheimer's Disease Mouse Models.

Preclinical and clinical studies have indicated that compromised blood-brain barrier (BBB) function contributes to Alzheimer's disease (AD) pathology. BBB breakdown ranged from mild disruption of tight junctions (TJs) with increased BBB permeability to chronic integrity loss, affecting transport across the BBB, reducing brain perfusion, and triggering inflammatory responses. We recently developed a high-throughput screening (HTS) assay to identify hit compounds that enhance the function of a cell-based BBB model. The HTS screen identified (S,E)-2-acetyl-6-[3-(4'-fluorobiphenyl-4-yl)acryloyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo-[b,d]furan-1(9bH)-one (4-FPBUA), a semisynthetic analogue of naturally occurring usnic acid, which protected the in vitro model against Aß toxicity. Usnic acid is a lichen-derived secondary metabolite with a unique dibenzofuran skeleton that is commonly found in lichenized fungi of the genera Usnea. In this study, we aimed to evaluate the effect of 4-FPBUA in vitro on the cell-based BBB model function and its in vivo ability to rectify BBB function and reduce brain Aß in two AD mouse models, namely, 5xFAD and TgSwDI. Our findings demonstrated that 4-FPBUA enhanced cell-based BBB function, increased Aß transport across the monolayer, and reversed BBB breakdown in vivo by enhancing autophagy as an mTOR inhibitor. Induced autophagy was associated with a significant reduction in Aß accumulation and related pathologies and improved memory function. These results underscore the potential of 4-FPBUA as a candidate for further preclinical exploration to better understand its mechanisms of action and to optimize dosing strategies. Continued research may also elucidate additional pathways through which 4-FPBUA contributed to the amelioration of BBB dysfunction in AD. Collectively, our findings supported the development of 4-FPBUA as a therapeutic agent against AD.

Chemically synthesized osteocalcin alleviates NAFLD via the AMPK-FOXO1/BCL6-CD36 pathway.

Nonalcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide. Osteocalcin plays an important role in energy metabolism. In this study, we investigated the mechanism of action of chemically synthesized osteocalcin (csOCN) in ameliorating NAFLD. We demonstrated for the first time that csOCN attenuates lipid accumulation in the liver and hepatocytes by modulating CD36 protein expression. In addition, we found that the expression of p-AMPK, FOXO1 and BCL6 decreased and the expression of CD36 increased after OA/PA induction compared to the control group, and these effects were reversed by the addition of csOCN. In contrast, the therapeutic effect of csOCN was inhibited by the addition of AMPK inhibitors and BCL6 inhibitors. This finding suggested that csOCN regulates CD36 expression via the AMPK-FOXO1/BCL6 axis. In NAFLD mice, oral administration of csOCN also activated the AMPK pathway and reduced CD36 expression. Molecular docking revealed that osteocalcin has a docking site with CD36. Compared to oleic acid and palmitic acid, osteocalcin bound more strongly to CD36. Laser confocal microscopy results showed that osteocalcin colocalized with CD36 at the cell membrane. In conclusion, we demonstrated the regulatory role of csOCN in fatty acid uptake pathways for the first time; it regulates CD36 expression via the AMPK-FOXO1/BCL6 axis to reduce fatty acid uptake, and it affects fatty acid transport by may directly binding to CD36. There are indications that csOCN has potential as a CD36-targeted drug for the treatment of NAFLD.

Knockdown of NFIL3 modulates the AMPK pathway to suppress excessive cell proliferation, inflammation, and migration in rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is one autoimmune disease that badly influences the lives of humans. Nuclear factor interleukin 3 (NFIL3) has been elucidated to join into the progression of diversiform diseases. According to a recent report, NFIL3 expression levels are increased in the peripheral blood and synovial tissues of individuals with RA. However, the detailed regulatory impacts of NFIL3 and associated pathways in RA progression need more investigations. METHODS: The mRNA and protein expressions were tested through RT-qPCR and western blot. The cell proliferation was evaluated through CCK-8 and EdU assay. The cell apoptosis was measured through flow cytometry. The levels of TNF-α, IL-6, and IL-8 were assessed through ELISA. The cell migration and invasion were tested through Transwell assay. RESULTS: In this study, NFIL3 exhibited higher expression in RA fibroblast-like synoviocytes (interleukin-1ß [IL-1ß]-triggered MH7A cell model). In addition, knockdown of NFIL3 repressed the growth of IL-1ß-mediated MH7A cells. It was also demonstrated that suppressing NFIL3 resulted in reduced inflammatory reactions in IL-1ß-mediated MH7A cells. Suppression of NFIL3 alleviated cell migration and invasion in the RA cell model. Ultimately, it was demonstrated that NFIL3 retarded the AMPK/mTOR pathway. CONCLUSION: This study demonstrated that the inhibition of NFIL3 effectively controlled the AMPK/mTOR pathway, thereby suppressing the overactive proliferation, inflammation, and migration of fibroblast-like synoviocytes in human RA. This discovery implied that NFIL3 can be a serviceable biomarker for RA therapy.

New concepts in the roles of AMPK in adipocyte stem cell biology.

Obesity is a major risk factor for many life-threatening diseases. Adipose tissue dysfunction is emerging as a driving factor in the transition from excess adiposity to comorbidities such as metabolic-associated fatty liver disease, cardiovascular disease, Type 2 diabetes and cancer. However, the transition from healthy adipose expansion to the development of these conditions is poorly understood. Adipose stem cells, residing in the vasculature and stromal regions of subcutaneous and visceral depots, are responsible for the expansion and maintenance of organ function, and are now recognised as key mediators of pathological transformation. Impaired tissue expansion drives inflammation, dysregulation of endocrine function and the deposition of lipids in the liver, muscle and around vital organs, where it is toxic. Contrary to previous hypotheses, it is the promotion of healthy adipose tissue expansion and function, not inhibition of adipogenesis, that presents the most attractive therapeutic strategy in the treatment of metabolic disease. AMP-activated protein kinase, a master regulator of energy homeostasis, has been regarded as one such target, due to its central role in adipose tissue lipid metabolism, and its apparent inhibition of adipogenesis. However, recent studies utilising AMP-activated protein kinase (AMPK)-specific compounds highlight a more subtle, time-dependent role for AMPK in the process of adipogenesis, and in a previously unexplored repression of leptin, independent of adipocyte maturity. In this article, I discuss historic evidence for AMPK-mediated adipogenesis inhibition and the multi-faceted roles for AMPK in adipose tissue.

Sarcopenia is attenuated by mairin in SAMP8 mice via the inhibition of FAPs fibrosis through the AMPK-TGF-ß-SMAD axis.

Sarcopenia has become a prominent health problem among the elderly because of its adverse consequence, including physical disabilities and death. Fibro-adipogenic progenitors (FAPs) exhibit adipogenic and fibrogenic potencies and regulate skeletal muscle development, which plays important role in sarcopenia. Mairin, as an ingredient of Astragalus membranaceus, has the effect of anti-fibrosis. Therefore, we predicted that mairin targeted the fibrosis of FAPs and then affected sarcopenia. To verify our ideas, mairin (30 mg/kg/day or 60 mg/kg/day) was given to senescence accelerated mouse-prone 8 (SAMP8) mice by oral administration. Aging led to loss of weight, skeletal muscle mass, strength, and function, and an increase in muscle atrophy and fibrosis, while mairin administration inhibited physiological decline caused by aging. Similarly, mairin (20 µM or 40 µM) treatment enhanced FAP proliferation but blocked the differentiation into fibroblasts. Mechanically, mairin played an anti-fibrotic role via AMP-activated protein kinase-transforming growth factor beta-drosophila mothers against decapentaplegic protein (AMPK-TGF-ß-SMAD) axis, as evidenced by increased phosphorylation of AMPKα and decreased TGF-ß and phosphorylated-SMAD2/3. In addition, the potential target genes of mairin were explored by mRNA sequencing in our study. In conclusion, mairin may interfere with the AMPK/TGF-ß/SMAD pathway to repress the fibrosis of FAPs and eventually ameliorate sarcopenia.

Fine-tuning AMPK in physiology and disease using point-mutant mouse models.

AMP-activated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that monitors the cellular energy status to adapt it to the fluctuating nutritional and environmental conditions in an organism. AMPK plays an integral part in a wide array of physiological processes, such as cell growth, autophagy and mitochondrial function, and is implicated in diverse diseases, including cancer, metabolic disorders, cardiovascular diseases and neurodegenerative diseases. AMPK orchestrates many different physiological outcomes by phosphorylating a broad range of downstream substrates. However, the importance of AMPK-mediated regulation of these substrates in vivo remains an ongoing area of investigation to better understand its precise role in cellular and metabolic homeostasis. Here, we provide a comprehensive overview of our understanding of the kinase function of AMPK in vivo, as uncovered from mouse models that harbor phosphorylation mutations in AMPK substrates. We discuss some of the inherent limitations of these mouse models, highlight the broader implications of these studies for understanding human health and disease, and explore the valuable insights gained that could inform future therapeutic strategies for the treatment of metabolic and non-metabolic disorders.

Maternal high-fat diet regulates offspring hepatic ABCG5 expression and cholesterol metabolism via the gut microbiota and its derived butyrate.

Maternal high-fat diet intake has profound effects on the long-term health of offspring, predisposing them to a higher susceptibility to obesity and metabolic dysfunction-associated steatotic liver disease. However, the detailed mechanisms underlying the role of a maternal high-fat diet in hepatic lipid accumulation in offspring, especially at the weaning age, remain largely unclear. In this study, female C57BL/6J mice were randomly assigned to either a high-fat diet or a control diet, and lipid metabolism parameters were assessed in male offspring at weaning. Gut microbiota analysis and targeted metabolomics of short-chain fatty acids (SCFAs) in these offspring were further performed. Both in vivo and in vitro studies were conducted to explore the role of butyrate in hepatic cholesterol excretion in the liver and HepG2 cells. Our results showed that maternal high-fat feeding led to obesity and dyslipidemia, and exacerbated hepatic lipid accumulation in the livers of offspring at weaning. We observed significant decreases in the abundance of the Firmicutes phylum and the Allobaculum genus, known as producers of SCFAs, particularly butyrate, in the offspring of dams fed a high-fat diet. Additionally, maternal high-fat diet feeding markedly decreased serum butyrate levels and down-regulated ATP-binding cassette transporters G5 (ABCG5) in the liver, accompanied by decreased phosphorylated AMP-activated protein kinase (AMPK) and histone deacetylase 5 (HADC5) expressions. Subsequent in vitro studies revealed that butyrate could induce ABCG5 activation and alleviate lipid accumulation via the AMPK-pHDAC5 pathway in HepG2 cells. Moreover, knockdown of HDAC5 up-regulated ABCG5 expression and promoted cholesterol excretion in HepG2 cells. In conclusion, our study provides novel insights into how maternal high-fat diet feeding inhibits hepatic cholesterol excretion and down-regulates ABCG5 through the butyrate-AMPK-pHDAC5 pathway in offspring at weaning.

Isobavachin induces autophagy-mediated cytotoxicity in AML12 cells via AMPK and PI3K/Akt/mTOR pathways.

Isobavachin (IBA) is a dihydroflavonoid compound with various pharmacological effects. However, further investigation into the hepatotoxicity of IBA is necessary. This study aims to identify the hepatotoxic effects of IBA and explore its potential mechanisms. The study assessed the impact of IBA on the viability of AML12, HepG2, LO2, rat, and mouse primary hepatocytes using MTT and LDH assays. Autophagy was detected in AML12 cells after IBA treatment using electron microscopy, MDC, and Ad-mCherry-GFP-LC3B fluorescence. The effect of IBA on autophagy-related proteins was examined using Western blot. The results showed that IBA had dose-dependent inhibitory effects on five cells, induced autophagy in AML12 cells, and promoted autophagic flux. The study found that IBA treatment inhibited phosphorylation of PI3K, Akt, and mTOR, while increasing phosphorylation levels of AMPK and ULK1. Treatment with both AMPK and PI3K inhibitors reversed the expression of AMPK and PI3K-Akt-mTOR signaling pathway proteins. These results suggest that IBA may have hepatocytotoxic effects but can also prevent IBA hepatotoxicity by inhibiting the AMPK and PI3K/Akt/mTOR signaling pathways. This provides a theoretical basis for preventing and treating IBA hepatotoxicity in clinical settings.

Far-infrared radiation alleviates steatohepatitis and fibrosis in metabolic dysfunction-associated fatty liver disease.

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a disease that causes an abnormal accumulation of fat in the liver, triggering inflammation and fibrosis, the mechanism of which is not fully understood and for which there is a lack of specific drug therapy. Far-infrared radiation (FIR) has demonstrated evident therapeutic efficacy across various diseases, and novel nanomaterial graphene patches can emit it through electric heating. This study aimed to investigate the potential protective effects of FIR against MAFLD. Mice were fed with a MCD diet to mimic MAFLD progression, and histopathology analysis, biochemical analysis, RT-qPCR, and Western blotting analysis were performed to assess the effect of FIR on MAFLD in vivo. The effect of FIR treatment on MAFLD in vitro was investigated by biochemical analysis and gene expression profiling of hepatocytes. Mice subjected to the MCD diet and treated with FIR exhibited reduced hepatic lipid deposition, inflammation, fibrosis and liver damage. The therapeutic effect exerted by FIR in mice may be caused by the enhancement of AMPK phosphorylation and inhibition of the TGFß1-SMAD2/3 pathway. Besides, FIR intervention alleviated MAFLD in hepatocytes in vitro and the results were verified by gene expression profiling. Our results revealed a promising potential of FIR as a novel therapeutic approach for MAFLD.

Carbon monoxide-loaded red blood cells ameliorate metabolic dysfunction-associated steatohepatitis progression via enhancing AMP-activated protein kinase activity and inhibiting Kupffer cell activation.

Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive form of nonalcoholic fatty liver disease characterised by fat accumulation, inflammation, oxidative stress, fibrosis, and impaired liver regeneration. In this study, we found that heme oxygenase-1 (HO-1) is induced in both MASH patients and in a MASH mouse model. Further, hepatic carbon monoxide (CO) levels in MASH model mice were >2-fold higher than in healthy mice, suggesting that liver HO-1 is activated as MASH progresses. Based on these findings, we used CO-loaded red blood cells (CO-RBCs) as a CO donor in the liver, and evaluated their therapeutic effect in methionine-choline deficient diet (MCDD)-induced and high-fat-diet (HFD)-induced MASH model mice. Intravenously administered CO-RBCs effectively delivered CO to the MASH liver, where they prevented fat accumulation by promoting fatty acid oxidation via AMP-activated protein kinase (AMPK) activation and peroxisome proliferator-activated receptor induction. They also markedly suppressed Kupffer cell activation and their corresponding anti-inflammatory and antioxidative stress activities in MASH mice. CO-RBCs also helped to restore liver regeneration in mice with HFD-induced MASH by activating AMPK. We confirmed the underlying mechanisms by performing in vitro experiments in RAW264.7 cells and palmitate-stimulated HepG2 cells. Taken together, CO-RBCs show potential as a promising cellular treatment for MASH.

Exploration of the mechanism of fraxetin in treating acute myeloid leukemia based on network pharmacology and experimental verification.

Objective: To explore the pharmacological mechanism of the effect of fraxetin in treating acute myeloid leukemia (AML) by the network pharmacology method combined with experimental validation. Methods: The targets of fraxetin were identified through Swisstarget prediction, PhammerMap, and CTDBASE. Disease-related targets of AML were explored using GeneCards and DisGenet databases, and the intersected targets were analyzed in the String website to construct a protein-protein interaction (PPI) network. Subsequently, gene ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were conducted using the DAVID database. Molecular docking of core proteins with drugs was performed using Auto Dock Vina software. Finally, the effect of fraxetin on AML was evaluated by in vitro experiments. The effect of fraxetin on AML cell proliferation was assessed by CCK8, the effect of fraxetin on AML cell apoptosis was assessed by flow cytometry, and the expression of relevant protein targets was detected by Western blotting to evaluate the anti-AML effect of fraxetin. Results: In this study, fraxetin exerts its effect against AML through 101 intersecting genes. The pathway enrichment analysis revealed that the pharmacological effects of fraxetin on AML were related to the Adenosine 5'-monophosphate (AMP)-activated protein kinase （AMPK） signaling pathway, and the molecular docking results indicated that fraxetin had an excellent binding affinity to both the core target and AMPK. In vitro experiments have demonstrated that fraxetin inhibited the proliferation and induced apoptosis of THP1 and HL60 cells, and the western blotting results indicated that the p-AMPK of the fraxetin intervention group was significantly changed in a dose-dependent manner. Conclusion: Fraxetin may modulate the AMPK signal pathway by interactine with the core target, thereby potentially therapeutic effect on AML.

Nrf2 cell signaling pathway is responsible for the antioxidant effect of resveratrol in aging.

INTRODUCTION: One of the markers of aging is oxidative stress, a condition characterized by an increase in free radicals concomitant with a reduction in antioxidant defenses. Within this, resveratrol is a compound that has been shown to act as a potent antioxidant. However, few studies highlight the cellular signaling pathways that are activated or inhibited during aging and that are responsible for this biological effect. AIM: To verify the antioxidant profile of resveratrol (5 µM) in leukocytes from donors in different age groups. METHODS: The project was approved by the Ethics Committee. Individuals were divided into three groups: 20-39, 40-59, and 60-80 years old. After separating the leukocytes, assays were performed to evaluate the AMPK (AMP-activated protein kinase) and Nrf2 (erythroid nuclear factor 2-related factor 2) pathways. In addition, luciferase assay and enzyme-linked immunosorbent assay were performed to evaluate transcription factor activation and Nrf2 expression, respectively. The analysis between age and treatment was performed using Pearson correlation (*P < 0.05). RESULTS: There was a reduction in the antioxidant effect of resveratrol during the aging process. In leukocytes from donors over 60 years of age, the AMPK pathway was silenced. Nrf2 was active at all ages. There was an increase in the activation of the transcription factor and phosphorylated protein in all age groups. CONCLUSIONS: Nrf2 is an important biochemical mechanism responsible for the antioxidant effect of resveratrol. This effect diminishes with aging but is still observed. Geriatr Gerontol Int 2024; ••: ••-••.

Ginsenoside Re inhibits non-small cell lung cancer progression by suppressing macrophage M2 polarization induced by AMPKα1/STING positive feedback loop.

Tumor-associated macrophages (TAMs) in non-small cell lung cancer (NSCLC) promote tumor cell metastasis by interacting with cancer cells. Ginsenoside Re is capable of modulating the host immune system and exerts anticancer effects through multiple pathways. Both AMPK and STING are involved in the regulation of MΦ polarization, thereby affecting tumor progression. However, whether there is a regulatory relationship between them and its effect on MΦ polarization and tumor progression is unclear. The aim of this study was to provide mechanistic evidence that ginsenoside Re modulates MΦ phenotype through inhibition of the AMPKα1/STING positive feedback loop and thus exerts an antimetastatic effect in NSCLC immunotherapy. Cell culture models and conditioned media (CM) systems were constructed, and the treated MΦ were analyzed by database analysis, RT-PCR, Western blotting, flow cytometry, and immunofluorescence to determine the regulatory relationship between AMPK and STING and the effects of ginsenoside Re on MΦ polarization and tumor cells migration. The effects of ginsenoside Re (10, 20 mg/kg/day) on TAMs phenotype as well as tumor progression in mice were assessed by HE staining, immunohistochemical staining, and Western blotting. In this study, AMPKα1/STING positive feedback loop in NSCLC TAMs induced M2 type polarization, which in turn promoted NSCLC cell migration. In addition, ginsenoside Re was discovered to inhibit M2-like MΦ polarization, thereby inhibiting NSCLC cell migration. Mechanistically, Re was able to inhibit the formation of the AMPKα1/STING positive feedback loop, thereby inhibiting its induction of M2-like MΦ and consequently inhibiting the epithelial-mesenchymal transition (EMT) process of NSCLC cells. Furthermore, in mouse models, Re was found to suppress LLC tumor growth and colonization by inhibiting M2-type polarization of TAMs. Our finding indicates that ginsenoside Re can effectively modulate MΦ polarization and thus play an important role in antimetastatic immunotherapy of NSCLC.

Adiponectin receptor agonist AdipoRon alleviates memory impairment in the hippocampus of septic mice.

Sepsis-associated encephalopathy (SAE) is a common and severe clinical feature of sepsis; however, therapeutic approaches are limited because of the unclear pathogenesis. Adiponectin receptor agonist (AdipoRon) is a small-molecule agonist of the adiponectin receptor that exhibits anti-inflammatory and memory-improving effects in various diseases. In the present study, we established lipopolysaccharide (LPS)-induced mice models of SAE and found that Adiponectin receptor 1 (AdipoR1) was significantly decreased in the hippocampus. Administration of AdipoRon improves memory impairment, mitigates synaptic damage, and alleviates neuronal death. Furthermore, AdipoRon reduces the number of microglia. More importantly, AdipoRon promotes the phosphorylation of adenosine 5 '-monophosphate activated protein kinase (pAMPK). In conclusion, AdipoRon is protective against SAE-induced memory decline and brain injury in the SAE models via activating the hippocampal adenosine 5 '-monophosphate activated protein kinase (AMPK).

The glycolysis-related AMPK/ULK signaling pathway mediates the inhibitory effect of adiponectin in prostate cancer cells.

OBJECTIVE: Reduced adiponectin (ADPN) levels have been implicated in the pathogenesis of prostate cancer (PCa). The role of glycolysis in cancer development and treatment has attracted increasing attention. The present study aimed to elucidate its impact on PCa and to explore the mechanistic involvement of glycolysis. METHODS: An RM-1 cell xenograft model of Adpn-knockout mice was used to corroborate the effects of glycolysis, AMP-activated protein kinase (AMPK) signaling, and autophagy on tumor xenograft progression. The effect of ADPN on PCa cells was evaluated using the Cell Counting Kit-8 (CCK-8), lactate levels, and flow cytometry. The expression of glycolysis-related genes was detected using real-time RT-PCR in LNCaP and PC-3 cells after incubation with ADPN. Autophagic flux after ADPN treatment was quantified by chloroquine intervention and confocal analysis of mRFP-GFP-LC3. Alterations in the levels of adiponectin receptor 1 (AdipoR1), AMPK, Unc-51-like kinase 1 (ULK1), autophagy-related protein 7 (ATG7), p62, and microtubule-associated protein 1 light chain 3 beta (LC3B) were assessed after incubation of LNCaP cells with ADPN. RESULTS: Proteomic analysis of xenograft tumors demonstrated significant upregulation of glycolysis in Adpn-/- mice. Lower levels of ADPN accelerated tumor xenograft growth, diminished p-AMPKα/AMPKα ratio and LC3B II/I ratio, and elevated levels of proliferating cell nuclear antigen (PCNA) within the tumor microenvironment. ADPN inhibited proliferation and glycolysis and potentiated apoptosis in both cell lines. Expression of glycolysis-related genes decreased after ADPN treatment. Autophagic flux was elevated, as evidenced by changes in autophagy-related proteins and confocal microscopy analysis of mRFP-GFP-LC3. It led to the suppression of p62 while inducing phosphorylation of AMPKα and upregulating AdipoR1, ULK1, ATG7, and LC3B II/I ratio. CONCLUSION: ADPN inhibited the proliferation and progression of PCa cell-derived tumor xenografts by inhibiting glycolysis. Specifically, ADPN effectively inhibits glycolysis and activates the downstream AMPK/ULK1 signaling pathway to suppress proliferation of PCa cells.

The role and mechanism of AMPK in pulmonary hypertension.

Pulmonary hypertension (PH) is a chronic progressive disease with high mortality. There has been more and more research focusing on the role of AMPK in PH. AMPK consists of three subunits-α, ß, and γ. The crosstalk among these subunits ultimately leads to a delicate balance to affect PH, which results in conflicting conclusions about the role of AMPK in PH. It is still unclear how these subunits interfere with each other and achieve balance to improve or deteriorate PH. Several signaling pathways are related to AMPK in the treatment of PH, including AMPK/eNOS/NO pathway, Nox4/mTORC2/AMPK pathway, AMPK/BMP/Smad pathway, and SIRT3-AMPK pathway. Among these pathways, the role and mechanism of AMPK/eNOS/NO and Nox4/mTORC2/AMPK pathways are clearer than others, while the SIRT3-AMPK pathway remains still unclear in the treatment of PH. There are drugs targeting AMPK to improve PH, such as metformin (MET), MET combination, and rhodiola extract. In addition, several novel factors target AMPK for improving PH, such as ADAMTS8, TUFM, and Salt-inducible kinases. However, more researches are needed to explore the specific AMPK signaling pathways involved in these novel factors in the future. In conclusion, AMPK plays an important role in PH.

Network pharmacology and experimental verification revealing valnemulin alleviates DSS-induced ulcerative colitis by inhibiting intestinal senescence.

Ulcerative colitis (UC) is a chronic inflammatory disease that is increasing in prevalence globally. Senescence is characterized by a specific chronic, low-grade, "sterile" inflammatory state known as inflammaging, suggesting that senescence may exacerbate the severity of UC. However, the link between UC and senescence remains unclear. Valnemulin (VAL) is a semi-synthetic derivative of a naturally occurring diterpenoid antibiotic (pleuromutilin), which can inhibit peptidyl transferase. Studies investigating the potential of valnemulin to inhibit senescence and alleviate colitis are currently limited. In this study, we revealed that dextran sulfate sodium (DSS), an inducer of UC, induces senescence in both colon epithelial NCM460 cells and colon tissues. Additionally, VAL, identified from a compound library, exhibited robust anti-senescence activity in DSS-treated NCM460 cells. Identified in our study as an anti-senescence agent, VAL effectively mitigated DSS-induced UC and colonic senescence in mice. Through network pharmacology analysis and experimental validation, the potential signaling pathway (AMPK/NF-κB) for VAL in treating UC was identified. We discovered that DSS significantly inhibited the AMPK signaling pathway and activated the NF-κB signaling pathway. However, supplementation with VAL remarkably restored AMPK activity and inhibited the NF-κB signaling pathway, which led to the inhibition of senescence. In summary, our study demonstrated that DSS-induced UC stimulates the senescence of colonic tissues, and VAL can effectively alleviate DSS-induced colonic damage and reduce colonic senescence. Our research findings provide a new perspective for targeting anti-senescence in the treatment of UC.

Cannabinoid receptor 2 agonist AM1241 alleviates epileptic seizures and epilepsy-associated depression via inhibiting neuroinflammation in a pilocarpine-induced chronic epilepsy mouse model.

Increasing evidence suggests that cannabinoid receptor 2 (CB2R) serves as a promising anti-inflammatory target. While inflammation is known to play crucial roles in the pathogenesis of epilepsy, the involvement of CB2R in epilepsy remains unclear. This study aimed to investigate the effects of a CB2R agonist, AM1241, on epileptic seizures and depressive-like behaviors in a mouse model of chronic epilepsy induced by pilocarpine. A chronic epilepsy mouse model was established by intraperitoneal administration of pilocarpine. The endogenous cannabinoid system (eCBs) in the hippocampus was examined after status epilepticus (SE). Animals were then treated with AM1241 and compared with a vehicle-treated control group. Additionally, the role of the AMPK/NLRP3 signaling pathway was explored using the selective AMPK inhibitor dorsomorphin. Following SE, CB2R expression increased significantly in hippocampal microglia. Administration of AM1241 significantly reduced seizure frequency, immobility time in the tail suspension test, and neuronal loss in the hippocampus. In addition, AM1241 treatment attenuated microglial activation, inhibited pro-inflammatory polarization of microglia, and suppressed NLRP3 inflammasome activation in the hippocampus after SE. Further, the therapeutic effects of AM1241 were abolished by the AMPK inhibitor dorsomorphin. Our findings suggest that CB2R agonist AM1241 may alleviate epileptic seizures and its associated depression by inhibiting neuroinflammation through the AMPK/NLRP3 signaling pathway. These results provide insight into a novel therapeutic approach for epilepsy.

Sodium butyrate improves renal injury in diabetic nephropathy through AMPK/SIRT1/PGC-1α signaling pathway.

Diabetic nephropathy (DN) is a prototypical chronic energy metabolism imbalance disease. The AMPK/Sirt1/PGC-1α signaling pathway plays a pivotal role in regulating energy metabolism throughout the body. Gut microbiota ferment indigestible carbohydrates to produce a variety of metabolites, particularly short-chain fatty acids (SCFAs), which exert positive effects on energy metabolism. However, the potential for SCFAs to ameliorate DN-associated renal injury via the AMPK/Sirt1/PGC-1α pathway remains a matter of debate. In this study, we investigated the effects of sodium butyrate (NaB), a SCFA, on energy metabolism in mice with spontaneous DN at two different doses. Body weight, blood glucose and lipid levels, urinary protein excretion, liver and kidney function, interleukin-6 (IL-6) levels, and the expressions of AMPK, phosphorylated AMPK (p-AMPK), mitofusin 2 (MFN2), optic atrophy 1 (OPA1), and glucagon-like peptide-1 receptor (GLP-1R) were monitored in mice. Additionally, butyrate levels, gut microbiota composition, and diversity in colonic stool were also assessed. Our findings demonstrate that exogenous NaB supplementation can improve hyperglycemia and albuminuria, reduce renal tissue inflammation, inhibit extracellular matrix accumulation and glomerular hypertrophy, and could alter the gut microbiota composition in DN. Furthermore, NaB was found to upregulate the expressions of MFN2, OPA1, p-AMPK, and GLP-1R in DN renal tissue. These results suggest that NaB could improve the composition of gut microbiota in DN, activate the AMPK/Sirt1/PGC-1α signaling pathway, and enhance mitochondrial function to regulate energy metabolism throughout the body. Collectively, our findings indicate that NaB may be a novel therapeutic agent for the treatment of DN.

PPARß/δ attenuates hepatic fibrosis by reducing SMAD3 phosphorylation and p300 levels via AMPK in hepatic stellate cells.

The role of peroxisome proliferator-activated receptor (PPAR)ß/δ in hepatic fibrosis remains a subject of debate. Here, we examined the effects of a PPARß/δ agonist on the pathogenesis of liver fibrosis and the activation of hepatic stellate cells (HSCs), the main effector cells in liver fibrosis, in response to the pro-fibrotic stimulus transforming growth factor-ß (TGF-ß). The PPARß/δ agonist GW501516 completely prevented glucose intolerance and peripheral insulin resistance, blocked the accumulation of collagen in the liver, and attenuated the expression of inflammatory and fibrogenic genes in mice fed a choline-deficient high-fat diet (CD-HFD). The antifibrogenic effect of GW501516 observed in the livers CD-HFD-fed mice could occur through an action on HSCs since primary HSCs isolated from Ppard-/- mice showed increased mRNA levels of the profibrotic gene Col1a1. Moreover, PPARß/δ activation abrogated TGF-ß1-mediated cell migration (an indicator of cell activation) in LX-2 cells (immortalized activated human HSCs). Likewise, GW501516 attenuated the phosphorylation of the main downstream intracellular protein target of TGF-ß1, suppressor of mothers against decapentaplegic (SMAD)3, as well as the levels of the SMAD3 co-activator p300 via the activation of AMP-activated protein kinase (AMPK) and the subsequent inhibition of extracellular signal-regulated kinase-1/2 (ERK1/2) in LX-2 cells. Overall, these findings uncover a new mechanism by which the activation of AMPK by a PPARß/δ agonist reduces TGF-ß1-mediated activation of HSCs and fibrosis via the reduction of both SMAD3 phosphorylation and p300 levels.