AMPK signalling in health and disease

Metformin and rosiglitazone affect motility, lipid peroxidation and mitochondrial activity of thawed equine spermatozoa

Maintaining sperm energy homeostasis in vitro is very important to improve the efficacy of stallion sperm preservation. Equine spermatozoa preferentially utilize oxidative phosphorylation over glycolysis to generate ATP. Metformin and rosiglitazone are antidiabetic compounds that enhances metabolic flexibility and glucose utilization. The aim of this study was to evaluate metformin and rosiglitazone supplementation of the freezing medium on quality and oxidative status of thawed stallion semen. A total of 15 ejaculates from five horses were collected and supplemented before freezing with metformin at 20 (M20), 50 (M50) and 100 mM (M100) and with rosiglitazone at 10 (R10), 50 (R50) and 100 µM (R100). A control group without supplementation was added. Semen cryopreservation was performed using a programable freezing protocol. Post-thaw, motility and kinetics, vitality (SV), morphology, plasma membrane integrity (PMI), mitochondria membrane potential (ΔΨM), reactive oxygen species (ROS) and lipid peroxidation (LP) of sperm were evaluated. Mixed models were adjusted and means were compared using Tukey tests. Total motility of post-thawed semen increased with M20; M100 reduced motility and most of the sperm kinetic parameters, as well as SV and PMI (p < 0.05). A reduction in LP was observed with M20 and R100; also, M100 produced a higher population of spermatozoa with low and high ΔΨM (p < 0.05). No treatment, except R50, generated an overproduction of ROS. In conclusion, a dose of 20 mM metformin in the freezing extender for stallion semen could improve total motility and reduce lipid peroxidation of thawed spermatozoa.

Role in Preventing Alcoholic Liver Disease Progression: A Comparative Study of Whole-Component Finger Citron Essential Oil and Its Major Component D-Limonene

Background/Objectives: Chronic alcohol overconsumption triggers alcohol liver injury, and therapeutic strategies targeting alcohol-triggered oxidative stress and hepatic inflammatory responses represent potential approaches to ameliorating alcohol-related hepatotoxicity. This study aimed to determine the hepatoprotective activity of finger citron essential oil (FCEO) in alcoholic liver disease (ALD)-afflicted rats and explore its underlying mechanisms. In order to identify the effective components, we compared the effects of FCEO and D-limonene. Methods: The regulatory effects of FCEO on metabolic enzymes were systematically evaluated through in vitro experiments. In vivo studies were conducted to investigate and compare the hepatoprotective effects of FCEO and D-limonene. Staining methods, assay kits, and Western Blot were used to determine the roles of FCEO and D-limonene in the ALD rats. Results: We found that FCEO downregulated phase I metabolic enzymes and upregulated phase II metabolic enzymes in Buffalo Rat Liver-3A (BRL-3A) cells. FCEO and/or D-limonene intervention reduced transaminase levels in ALD rats and effectively alleviated inflammatory cell infiltration and lipid droplet accumulation in their liver tissue. Additionally, FCEO and D-limonene played a regulatory role in oxidative stress and inflammation-related pathways such as the MAPK/Nrf2 and NF-κB/AMPK pathways. FCEO was superior to D-limonene as an antioxidant in alleviating alcoholic liver injury. Conclusions: This study revealed the alleviative effects and mechanisms of FCEO on alcoholic liver injury, demonstrating better efficacy compared to its monomer, thus providing a strategy for the development and utilization of finger citron resources.

The Role and Molecular Pathways of SIRT6 in Senescence and Age-related Diseases

SIRT6 is a NAD+-dependent histone deacetylase with crucial roles in controlling DNA damage repair, telomere homeostasis, oxidative stress, autophagy, and other cellular processes, and it has long been recognized as a longevity-associated protein. This review details its anti-aging-related mechanisms. First, SIRT6 facilitates DNA repair pathways and maintains genome stability by deacetylating histone H3 at K56, K9, and K18 residues, in addition to participating in DNA damage repair through mono-ADP-ribosylation and other mechanisms. Second, SIRT6 preserves telomere integrity and mitigates cellular senescence by reducing oxidative stress-induced damage through the regulation of reactive oxygen species (ROS), inhibition of inflammation, and other pathways. Furthermore, SIRT6 promotes autophagy, slowing cellular senescence via the modulation of various signaling pathways, including AMPK, IGF-Akt-mTOR, H133Y, IL-1β, and mitochondrial autophagy-related proteins. Finally, SIRT6 regulates multiple signaling pathways, such asNF-κB, FOXO, and AMPK, to counteract the aging process. This review particularly delves into the interplay between SIRT6 and various diseases, including tumors, cardiovascular diseases (e.g., atherosclerosis, heart failure), metabolic diseases (e.g., type 2 diabetes, dyslipidemia, gluconeogenesis, osteoporosis), and neurodegenerative diseases (e.g., Alzheimer's disease). Moreover, recent advancements in SIRT6-regulated compounds (e.g., C3G, BZBS, Fisetin, FNDC5, Lycorine hydrochloride, and Ergothioneine) are discussed as potential therapeutic agents for these mediated diseases.

Survival strategies of cancer cells: the role of macropinocytosis in nutrient acquisition, metabolic reprogramming, and therapeutic targeting

Macropinocytosis is a nonselective form of endocytosis that allows cancer cells to largely take up the extracellular fluid and its contents, including nutrients, growth factors, etc. We first elaborate meticulously on the process of macropinocytosis. Only by thoroughly understanding this entire process can we devise targeted strategies against it. We then focus on the central role of the MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1) in regulating macropinocytosis, highlighting its significance as a key signaling hub where various pathways converge to control nutrient uptake and metabolic processes. The article covers a comprehensive analysis of the literature on the molecular mechanisms governing macropinocytosis, including the initiation, maturation, and recycling of macropinosomes, with an emphasis on how these processes are hijacked by cancer cells to sustain their growth. Key discussions include the potential therapeutic strategies targeting macropinocytosis, such as enhancing drug delivery via this pathway, inhibiting macropinocytosis to starve cancer cells, blocking the degradation and recycling of macropinosomes, and inducing methuosis - a form of cell death triggered by excessive macropinocytosis. Targeting macropinocytosis represents a novel and innovative approach that could significantly advance the treatment of cancers that rely on this pathway for survival. Through continuous research and innovation, we look forward to developing more effective and safer anti-cancer therapies that will bring new hope to patients.Abbreviation: AMPK: AMP-activated protein kinase; ASOs: antisense oligonucleotides; CAD: carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase; DC: dendritic cell; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; ERBB2: erb-b2 receptor tyrosine kinase 2; ESCRT: endosomal sorting complex required for transport; GAP: GTPase-activating protein; GEF: guanine nucleotide exchange factor; GRB2: growth factor receptor bound protein 2; LPP: lipopolyplex; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; MTORC2: mechanistic target of rapamycin kinase complex 2; NSCLC: non-small cell lung cancer; PADC: pancreatic ductal adenocarcinoma; PDPK1: 3-phosphoinositide dependent protein kinase 1; PI3K: phosphoinositide 3-kinase; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PtdIns(3,4,5)P3: phosphatidylinositol-(3,4,5)-trisphosphate; PtdIns(4,5)P2: phosphatidylinositol-(4,5)-bisphosphate; PTT: photothermal therapies; RAC1: Rac family small GTPase 1; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase B1; RTKs: receptor tyrosine kinases; SREBF: sterol regulatory element binding transcription factor; TFEB: transcription factor EB; TNBC: triple-negative breast cancer; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UPS: ubiquitin-proteasome system.

The emerging role of E3 ubiquitin ligases and deubiquitinases in metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver disease worldwide, with a prevalence as high as 32.4%. MASLD encompasses a spectrum of liver pathologies, ranging from steatosis to metabolic dysfunction-associated steatohepatitis (MASH), fibrosis, and, in some cases, progression to end-stage liver disease (cirrhosis and hepatocellular carcinoma). A comprehensive understanding of the pathogenesis of this highly prevalent liver disease may facilitate the identification of novel targets for the development of improved therapies. E3 ubiquitin ligases and deubiquitinases (DUBs) are key regulatory components of the ubiquitin‒proteasome system (UPS), which plays a pivotal role in maintaining intracellular protein homeostasis. Emerging evidence implicates that aberrant expression of E3 ligases and DUBs is involved in the progression of MASLD. Here, we review abnormalities in E3 ligases and DUBs by (1) discussing their targets, mechanisms, and functions in MASLD; (2) summarizing pharmacological interventions targeting these enzymes in preclinical and clinical studies; and (3) addressing challenges and future therapeutic strategies. This review synthesizes current evidence to highlight the development of novel therapeutic strategies based on the UPS for MASLD and progressive liver disease.

TF and TFRC regulate ferroptosis in swine testicular cells through the JNK signaling pathway

Transferrin (TF) is a serum glycoprotein that plays a critical role in iron metabolism and typically functions through binding to its transferrin receptor (TFRC). TF is also considered a key indicator of sperm quality and, together with TFRC, plays a critical role in regulating spermatogenesis. This study aimed to explore the effects of increased TF and TFRC expression on ferroptosis in swine testicular cells (ST cells). Our findings revealed that the overexpression of either TF or TFRC diminishes ST cell viability, increases cytotoxicity, intensifies oxidative stress damage, decreases mitochondrial activity, and promotes ferroptosis. Transcriptomic analysis suggested that TF and TFRC may influence ST cells through the MAPK signaling pathway. Subsequent experiments revealed that inhibiting the JNK signaling pathway within the MAPK pathway improved mitochondrial activity, reduced oxidative stress damage, and mitigated ferroptosis progression. Moreover, we discovered that TF and TFRC might regulate cellular oxidative phosphorylation via the JNK signaling pathway. In conclusion, increased expression of TF or TFRC increases the sensitivity of ST cells to ferroptosis and modulates mitochondrial DNA transcription and energy metabolism through the JNK signaling pathway. These findings could offer potential therapeutic targets for addressing reproductive toxicity associated with ferroptosis.

Action and therapeutic targets of folliculin interacting protein 1: a novel signaling mechanism in redox regulation

Rapid activation of adenosine monophosphate-activated protein kinase (AMPK) induces phosphorylation of mitochondrial-associated proteins, a process by which phosphate groups are added to regulate mitochondrial function, thereby modulating mitochondrial energy metabolism, triggering an acute metabolic response, and sustaining metabolic adaptation through transcriptional regulation. AMPK directly phosphorylates folliculin interacting protein 1 (FNIP1), leading to the nuclear translocation of transcription factor EB (TFEB) in response to mitochondrial functions. While mitochondrial function is tightly linked to finely-tuned energy-sensing mobility, FNIP1 plays critical roles in glucose transport and sensing, mitochondrial autophagy, cellular stress response, and muscle fiber contraction. Consequently, FNIP1 emerges as a promising novel target for addressing aberrant mitochondrial energy metabolism. Recent evidence indicates that FNIP1 is implicated in mitochondrial biology through various pathways, including AMPK, mTOR, and ubiquitination, which regulate mitochondrial autophagy, oxidative stress responses, and skeletal muscle contraction. Nonetheless, there is a dearth of literature discussing the physiological mechanism of action of FNIP1 as a novel therapeutic target. This review outlines how FNIP1 regulates metabolic-related signaling pathways and enzyme activities, such as modulating mitochondrial energy metabolism, catalytic activity of metabolic enzymes, and the homeostasis of metabolic products, thereby controlling cellular function and fate in different contexts. Our focus will be on elucidating how these metabolite-mediated signaling pathways regulate physiological processes and inflammatory diseases.

Mechanisms of ferroptosis and glucagon-like peptide-1 receptor agonist in post-percutaneous coronary intervention restenosis

Cardiovascular disease (CVD) claims millions of lives every year, with atherosclerotic cardiovascular disease (ASCVD) being the main cause. ASCVD treatment includes drug therapy, lifestyle intervention, and Percutaneous Coronary Intervention (PCI) all of which significantly enhance cardiovascular function and reduce mortality. However, hyperplasia can lead to vascular obstruction, worsen angina symptoms, or even cause heart disease, affecting patients' long-term prognosis. Therefore, finding effective ways to combat hyperplasia is crucial for cardiovascular therapy. In recent years, ferroptosis has gained attention as a new form of cell death closely associated with several diseases, including cardiovascular diseases. It involves complex metabolic processes critical for cellular homeostasis and normal function. Abnormal proliferation and phenotypic transformation of vascular smooth muscle cells (VSMC) are crucial mechanisms underlying cardiovascular disease development. Inhibiting ferroptosis in VSMC has the potential to significantly reduce neointima proliferation. Glucagon-like peptide-1 receptor agonist (GLP-1RA) constitutes a widely employed class of hypoglycemic agents with direct implications for the cardiovascular system, mitigating adverse cardiovascular events. Research indicates that the stimulation of GLP-1 holds promise as a therapeutic strategy in mitigating cardiovascular events such as restenosis. Hence, investigating the potential of GLP-1RA as a treatment option for cardiovascular ailments carries immense clinical significance.

BefA protein alleviates progression of non-alcoholic fatty liver disease by modulating the AMPK signaling pathway through the gut-liver axis

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver diseases worldwide, necessitating urgent novel oral treatments. In this study, β-cell expansion factor A (BefA) was evaluated in a murine NAFLD model induced by high-fat diet (HFD). Our results revealed that BefA significantly reduced body weight (36.58 ± 1.55 g vs. 42.30 ± 1.96 g, p < 0.01), fat mass-to-body weight ratio (0.023 ± 0.019 vs. 0.300 ± 0.019, p < 0.05), liver weight (1.90 ± 0.07 g vs. 2.31 ± 0.21 g, p < 0.05), and liver function parameters (ALT, AST, ALP levels reduced, p < 0.05). Notably, BefA reversed the pathological features of NAFLD, decreasing hepatic steatosis score from 3.67 ± 0.47 to 1.67 ± 0.47 (p < 0.01). Mechanistically, BefA activated the AMPK signaling pathway, resulting in the suppression of lipogenic gene transcription (ACC, FASN, SREBP-1c) and the enhancement of fatty acid oxidation (CPT-1, PPAR-α). However, AMPK inhibitor and broad-spectrum antibiotics significantly attenuated the benefits observed with BefA treatment, increasing body weight, fat-to-body weight ratio, and liver weight (p < 0.05). Similar detrimental effects were also observed in liver function indices and histopathological characteristics. These findings underscore the pivotal role of both gut microbiota modulation and AMPK signaling in BefA's therapeutic efficacy, making it a promising multitargeted approach for NAFLD treatment.

Transcriptomics-based investigation of resistance differences to swine fever between large white pigs and min pigs

The genetic foundations underlying the observed disease resistance in certain indigenous pig breeds, notably the Min pigs of China, present a compelling underexplored subject of study. Exploring the mechanisms of disease resistance in these breeds could lay the groundwork for genetic improvements in pig immunity, potentially augmenting overall pig productivity. In this study, whole blood samples were collected from pre- and post- swine fever vaccinated Min and Large White pigs for transcriptome sequencing. The mRNA and lncRNA in both pig breeds were analyzed, and intra-group and inter-group comparisons were also conducted. The results indicated that a greater number of immune-related pathways such as the JAK-STAT and PI3K-AKT signaling were enriched in Min pigs. Furthermore, genes involved in inflammation and antiviral responses, including IL16, IL27, USP18, and DHX58, were upregulated in post-vaccination Min pigs compared to post-vaccination Large White pigs. This heightened immune responsiveness could contribute to the observed differences in disease resistance between Min pigs and Large White pigs.

Intermittent fasting and neurodegenerative diseases: Molecular mechanisms and therapeutic potential

Neurodegenerative disorders are straining public health worldwide. During neurodegenerative disease progression, aberrant neuronal network activity, bioenergetic impairment, adaptive neural plasticity impairment, dysregulation of neuronal Ca2+ homeostasis, oxidative stress, and immune inflammation manifest as characteristic pathological changes in the cellular milieu of the brain. There is no drug for the treatment of neurodegenerative disorders, and therefore, strategies/treatments for the prevention or treatment of neurodegenerative disorders are urgently needed. Intermittent fasting (IF) is characterized as an eating pattern that alternates between periods of fasting and eating, requiring fasting durations that vary depending on the specific protocol implemented. During IF, depletion of liver glycogen stores leads to the production of ketone bodies from fatty acids derived from adipocytes, thereby inducing an altered metabolic state accompanied by cellular and molecular adaptive responses within neural networks in the brain. At the cellular level, adaptive responses can promote the generation of synapses and neurons. At the molecular level, IF triggers the activation of associated transcription factors, thereby eliciting the expression of protective proteins. Consequently, this regulatory process governs central and peripheral metabolism, oxidative stress, inflammation, mitochondrial function, autophagy, and the gut microbiota, all of which contribute to the amelioration of neurodegenerative disorders. Emerging evidence suggests that weight regulation significantly contributes to the neuroprotective effects of IF. By alleviating obesity-related factors such as blood-brain barrier dysfunction, neuroinflammation, and β-amyloid accumulation, IF enhances metabolic flexibility and insulin sensitivity, further supporting its potential in mitigating neurodegenerative disorders. The present review summarizes animal and human studies investigating the role and underlying mechanisms of IF in physiology and pathology, with an emphasis on its therapeutic potential. Furthermore, we provide an overview of the cellular and molecular mechanisms involved in regulating brain energy metabolism through IF, highlighting its potential applications in neurodegenerative disorders. Ultimately, our findings offer novel insights into the preventive and therapeutic applications of IF for neurodegenerative disorders.

Therapeutic Potential of Cranberry Proanthocyanidins in Addressing the Pathophysiology of Metabolic Syndrome: A Scrutiny of Select Mechanisms of Action

Metabolic syndrome (MetS) constitutes a spectrum of interconnected conditions comprising obesity, dyslipidemia, hypertension, and insulin resistance (IR). While a singular, all-encompassing treatment for MetS remains elusive, an integrative approach involving tailored lifestyle modifications and emerging functional food therapies holds promise in preventing its multifaceted manifestations. Our main objective was to scrutinize the efficacy of cranberry proanthocyanidins (PAC, 200 mg/kg/day for 12 weeks) in mitigating MetS pathophysiology in male mice subjected to standard Chow or high-fat/high-fructose (HFHF) diets while unravelling intricate mechanisms. The administration of PAC, in conjunction with an HFHF diet, significantly averted obesity, evidenced by reductions in body weight, adiposity across various fat depots, and adipocyte hypertrophy. Similarly, PAC prevented HFHF-induced hyperglycemia and hyperinsulinemia while also lessening IR. Furthermore, PAC proved effective in alleviating key risk factors associated with cardiovascular diseases by diminishing plasma saturated fatty acids, as well as levels of triglycerides, cholesterol, and non-HDL-C levels. The rise in adiponectin and drop in circulating levels of inflammatory markers showcased PAC's protective role against inflammation. To better clarify the mechanisms behind PAC actions, gut-liver axis parameters were examined, showing significant enhancements in gut microbiota composition, microbiota-derived metabolites, and marked reductions in intestinal and hepatic inflammation, liver steatosis, and key biomarkers associated with endoplasmic reticulum (ER) stress and lipid metabolism. This study enhances our understanding of the complex mechanisms underlying the development of MetS and provides valuable insights into how PAC may alleviate cardiometabolic dysfunction in HFHF mice.

Toward the Prediction of Binding Events in Very Flexible, Allosteric, Multidomain Proteins

Knowledge of the structures formed by proteins and small molecules is key to understand the molecular principles of chemotherapy and for designing new and more effective drugs. During the early stage of a drug discovery program, it is customary to predict ligand-protein complexes in silico, particularly when screening large compound databases. While virtual screening based on molecular docking is widely used for this purpose, it generally fails in mimicking binding events associated with large conformational changes in the protein, particularly when the latter involve multiple domains. In this work, we describe a new methodology to generate bound-like conformations of very flexible and allosteric proteins bearing multiple binding sites by exploiting only information on the unbound structure and the putative binding sites. The protocol is validated on the paradigm enzyme adenylate kinase, for which we generated a significant fraction of bound-like structures. A fraction of these conformations, employed in ensemble-docking calculations, allowed to find native-like poses of substrates and inhibitors (binding to the active form of the enzyme), as well as catalytically incompetent analogs (binding the inactive form). Our protocol provides a general framework for the generation of bound-like conformations of challenging drug targets that are suitable to host different ligands, demonstrating high sensitivity to the fine chemical details that regulate protein's activity. We foresee applications in virtual screening, in the prediction of the impact of amino acid mutations on structure and dynamics, and in protein engineering.

Proteomic insights into molecular alterations associated with Kawasaki disease in children

BACKGROUND

Kawasaki disease (KD) is a pediatric vasculitis that can lead to coronary artery complications if not promptly diagnosed. Its nonspecific early symptoms, primarily fever, often result in misdiagnosis. This study aimed to identify potential biomarkers for early KD diagnosis using proteomic analysis of blood samples.

METHODS

Serum samples were collected from three groups: children with acute KD (n = 20, CQB group), age-matched febrile children with bacterial infections (n = 20, C group), and children recovered from KD (n = 8, CQBC group). Proteomic analysis was performed to identify differentially expressed proteins in serum specimens, followed by functional and pathway enrichment analysis.

RESULTS

Compared to controls, 92 proteins were upregulated and 101 were downregulated in acute KD, with significant enrichment in the AMPK pathway. In recovered KD, 537 proteins were upregulated and 231 downregulated, predominantly affecting the PI3K-Akt pathway. A total of 56 proteins showed contrasting expression patterns between acute and recovery phases, implicating the complement and coagulation cascades. Notably, complement component 6 (C6), complement component 3 (C3), and α1-antitrypsin (A1AT) emerged as potential biomarkers involved in KD progression and recovery.

CONCLUSIONS

C6, C3, and A1AT may serve as novel biomarkers for early KD diagnosis and monitoring. These findings provide new insights into KD pathogenesis and potential targets for clinical application.

Development of the Pyrido[2,3-d]pyrimidin-7(8H)-one Scaffold toward Potent and Selective NUAK1 Inhibitors

The protein kinase NUAK1 has been implicated in various biological functions including cell adhesion, migration and proliferation. Genetic reduction of NUAK1 expression has notably been shown to lower total levels of human tau in a tauopathy mouse model, identifying this kinase as a potential therapeutic target for neurodegenerative disease. In this paper, we describe improvement of the NUAK1 potency, kinase-selectivity and pharmacokinetic properties of the brain-penetrant but unselective CDK4/CDK6/NUAK1 inhibitor ON123300. Through a scaffold-optimization approach we have identified different chemotypes delivering NUAK1 inhibition with improved potency and selectivity over CDK kinases compared with ON123300. We present ADME profiling and in vivo pharmacokinetic data for these compounds.

Small Molecule Modulators of AMP-Activated Protein Kinase (AMPK) Activity and Their Potential in Cancer Therapy

AMP-activated protein kinase (AMPK) is a central mediator of cellular metabolism and is activated in direct response to low ATP levels. Activated AMPK inhibits anabolic pathways and promotes catabolic activities that generate ATP through the phosphorylation of multiple target substrates. AMPK is a therapeutic target for activation in several chronic metabolic diseases, and there is increasing interest in targeting AMPK activity in cancer where it can act as a tumor suppressor or conversely it can support cancer cell survival. Small molecule AMPK activators and inhibitors have demonstrated some success in suppressing cancer growth, survival, and drug resistance in preclinical cancer models. In this perspective, we summarize the role of AMPK in cancer and drug resistance, the influence of the tumor microenvironment on AMPK activity, and AMPK activator and inhibitor development. In addition, we discuss the potential importance of isoform-selective targeting of AMPK and approaches for selective AMPK targeting in cancer.

Ovarian Aging: The Silent Catalyst of Age-Related Disorders in Female Body

Age-related diseases have emerged as a global concern as the population ages. Consequently, understanding the underlying causes of aging and exploring potential anti-aging interventions is imperative. In females, the ovaries serve as the principal organs responsible for ovulation and the production of female hormones. The aging ovaries are related to infertility, menopause, and associated menopausal syndromes, with menopause representing the culmination of ovarian aging. Current evidence indicates that ovarian aging may contribute to dysfunction across multiple organ systems, including, but not limited to, cognitive impairment, osteoporosis, and cardiovascular disease. Nevertheless, due to the widespread distribution of sex hormone receptors throughout the body, ovarian aging affects not only these specific organs but also influences a broader spectrum of age-related diseases in women. Despite this, the impact of ovarian aging on overall age-related diseases has been largely neglected. This review provides a thorough summary of the impact of ovarian aging on age-related diseases, encompassing the nervous, circulatory, locomotor, urinary, digestive, respiratory, and endocrine systems. Additionally, we have outlined prospective therapeutic approaches for addressing both ovarian aging and age-related diseases, with the aim of mitigating their impacts and preserving women's fertility, physical health, and psychological well-being.

1-phenyl-3-methyl-5-pyrazolone activates the AMPK pathway to alleviate western-diet induced metabolic dysfunction-associated steatohepatitis in mice

BACKGROUND & AIMS

Approved drugs for the treatment of metabolic dysfunction-associated steatohepatitis (MASH) are limited, although it has become the most common chronic liver disease worldwide. 1-phenyl-3-methyl-5-pyrazolone (PMP) possesses various biological effects such as anti-inflammatory and antioxidant. However, the effects and underlying mechanism of PMP in MASH remain unclear.

METHODS

Steatosis cells were induced by palmitate/oleic acid (PO). Then, the contents of lipids and reactive oxygen species were measured. To further investigate the effects of PMP on MASH models, C57BL/6J mice were fed a western diet (WD) for 24 weeks and PMP was administered daily by intragastric gavage. Serum enzymes and lipids were assayed by a biochemistry analyzer. RNA sequencing, real-time qPCR, and western blotting were used to measure the expression of different genes. Histological analysis of the liver included HE, Oil red O, and Sirius red staining.

RESULTS

PMP alleviated lipid accumulation and oxidative stress induced by PO (P < 0.001). In vivo, WD-induced significant elevation of blood glucose and serum lipids were reduced by PMP (P < 0.05). Furthermore, PMP effectively prevented hepatic steatosis, inflammation, and fibrosis in MASH mice. Western blot results suggested PMP promoted the phosphorylation of LKB1 and AMPKα at T172, which is a marker of activation of the AMPK pathway. RNA sequencing also demonstrated that PMP facilitated the activation of the AMPK pathway. Furthermore, the protective effects of PMP on steatosis cells and MASH mice disappeared after treatment with an AMPK inhibitor.

CONCLUSIONS

PMP protects against metabolic-stress-induced MASH through activating AMPK signaling, indicating that PMP may be a candidate for MASH therapy in the future.

SF1-specific deletion of the energy sensor AMPKγ2 induces obesity

OBJECTIVE

AMP-activated protein kinase (AMPK) is a heterotrimer complex consisting of a catalytic α subunit (α1, α2) with a serine/threonine kinase domain, and two regulatory subunits, β (β1, β2) and γ (γ1, γ2, γ3), encoded by different genes. In the hypothalamus, AMPK plays a crucial role in regulating energy balance, including feeding, energy expenditure, peripheral glucose and lipid metabolism. However, most research on hypothalamic AMPK has concentrated on the catalytic subunits AMPKα1 and AMPKα2, with little focus on the regulatory subunits.

METHODS

To fill this gap of knowledge, we investigated the effects of selectively deleting the regulatory isoform AMPKγ2, which is a primary "energy sensor", in steroidogenic factor 1 (SF1) neurons of the ventromedial hypothalamic nucleus (VMH). Complete metabolic phenotyping and molecular analyses in brown adipose tissue (BAT), white adipose tissue (WAT) and liver were carried out.

RESULTS

Our findings reveal that, in contrast to the obesity-protective effect of the genetic deletion of AMPKα subunits, the loss of AMPKγ2 in SF1 neurons leads to a sex-independent and feeding-independent obesity-prone phenotype due to decreased thermogenesis in brown adipose tissue (BAT) and reduced browning of WAT, resulting in lower energy expenditure. Additionally, SF1-Cre AMPKγ2 mice exhibit hepatic lipid accumulation, but surprisingly maintain normal glucose homeostasis.

CONCLUSIONS

Overall, these results highlight the distinct roles of AMPK subunits within the hypothalamus.

Network pharmacology-based strategy to reveal Acacetin against lipopolysaccharide-induced lung injury

BACKGROUND

Acacetin, a flavonoid isolated from Agastache rugosa, exhibits diverse biological activities, such as anti-tumor, anti-inflammatory and antioxidant activities. Its role in treating Lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains incompletely illuminated.

OBJECTIVE

To explore the potential molecular mechanisms of Acacetin in alleviating ALI.

MATERIALS & METHODS

The network pharmacological approach was employed to screen the target genes and pathways of Acacetin. Lung injury was analyzed by Hematoxylin-Eosin (H&E) staining. Bronchoalveolar lavage fluid, serum and lung tissues were collected to detect the levels of proinflammatory cytokines and oxidative stress markers. Immunofluorescence and RT-qPCR experiments were used to observe the expression of CD45, COX2, Ly6G, and related-target proteins. In vitro, RAW264.7 macrophages were stimulated with LPS and treated with AMPK siRNA or an AMPK inhibitor Coumpound C to verify the role of AMPK/nuclear factor erythroid 2-related factor 2 (Nrf2)/high-mobility group box 1 (HMGB1) signaling in Acacetin-mediated alleviation of ALI.

RESULTS

Network data revealed that Acacetin could regulate HMGB1, AMPK, Nrf2, and IL-6. In vivo, Acacetin reversed pathological damage and the release of inflammatory factors, and alleviated oxidative stress and immune cell infiltration in ALI development. Acacetin remarkably upregulated the expression of AMPK and Nrf2, accompanied by HMGB1 downregulation. In vitro, inhibiting AMPK reversed the effects of Acacetin in LPS-treated RAW264.7, due to inactivation of AMPK/Nrf2/HMGB1 pathway.

CONCLUSION

The combination of network pharmacology and experimental studies revealed the role of Acacetin in improving ALI via the AMPK/Nrf2/HMGB1 signaling axis, which provided new insights into the treatment of ALI with Acacetin as a candidate drug.

A Review of Telomere Attrition in Cancer and Aging: Current Molecular Insights and Future Therapeutic Approaches

BACKGROUND/OBJECTIVES

As cells divide, telomeres shorten through a phenomenon known as telomere attrition, which leads to unavoidable senescence of cells. Unprotected DNA exponentially increases the odds of mutations, which can evolve into premature aging disorders and tumorigenesis. There has been growing academic and clinical interest in exploring this duality and developing optimal therapeutic strategies to combat telomere attrition in aging and cellular immortality in cancer. The purpose of this review is to provide an updated overview of telomere biology and therapeutic tactics to address aging and cancer.

METHODS

We used the Rayyan platform to review the PubMed database and examined the ClinicalTrial.gov registry to gain insight into clinical trials and their results.

RESULTS

Cancer cells activate telomerase or utilize alternative lengthening of telomeres to escape telomere shortening, leading to near immortality. Contrarily, normal cells experience telomeric erosion, contributing to premature aging disorders, such as Werner syndrome and Hutchinson-Gilford Progeria, and (2) aging-related diseases, such as neurodegenerative and cardiovascular diseases.

CONCLUSIONS

The literature presents several promising therapeutic approaches to potentially balance telomere maintenance in aging and shortening in cancer. This review highlights gaps in knowledge and points to the potential of these optimal interventions in preclinical and clinical studies to inform future research in cancer and aging.

FRET-Based Sensor for Measuring Adenine Nucleotide Binding to AMPK

AMP-activated protein kinase (AMPK) has evolved to detect a critical increase in cellular AMP/ATP and ADP/ATP concentration ratios as a signal for limiting energy supply. Such energy stress then leads to AMPK activation and downstream events that maintain cellular energy homeostasis. AMPK activation by AMP, ADP, or pharmacological activators involves a conformational switch within the AMPK heterotrimeric complex. We have engineered an AMPK-based sensor, AMPfret, which translates the activating conformational switch into a fluorescence signal, based on increased fluorescence resonance energy transfer (FRET) between donor and acceptor fluorophores. Here we describe how this sensor can be used to analyze direct AMPK activation by small molecules in vitro using a fluorimeter, or to estimate changes in the energy state of cells using standard fluorescence or confocal microscopy.

Development of novel osteoarthritis therapy by targeting AMPK-β-catenin-Runx2 signaling

Osteoarthritis (OA) is a debilitating chronic joint disease affecting large populations of patients, especially the elderly. The pathological mechanisms of OA are currently unknown. Multiple risk factors are involved in OA development. Among these risk factors, alterations of mechanical loading in the joint leading to changes in biological signaling pathways have been known as a key event in OA development. The importance of AMPK-β-catenin-Runx2 signaling in the initiation and progression of OA has been recognized in recent years. In this review, we discuss the recent progress in understanding the role of this signaling pathway and the underlying interaction mechanisms during OA development. We also discuss the drug development aiming to target this signaling pathway for OA treatment.

Pharmacological targeting of AMPK to restore glucose and fatty acid metabolism homeostasis attenuates transplanted kidney fibrosis

Chronic fibrosis often occurs in transplanted kidneys, leading to progressive functional decline. The underlying mechanisms may involve disruption in the metabolism of renal tubular epithelial cells. The liver kinase B1 (LKB1)-AMPK pathway is a pivotal regulatory hub for glucose and fatty acid metabolism and may play a role in transplanted kidney fibrosis, but it has not been reported. In this study we administered fenofibrate, 2-deoxyglucose, or metformin to modulate metabolism in Brown Norway rat kidney transplants and investigated pathways involved in fibrosis using various assays. We identified an impaired LKB1-AMPK pathway within epithelial cells, resulting in perturbed glucose and fatty acid metabolism, collagen secretion, extracellular matrix remodeling, and epithelial-mesenchymal transition. ACOX1, a pivotal enzyme in the fatty acid peroxisomal β-oxidation pathway, played an important role in transplanted renal fibrosis. Furthermore, several metabolism-targeting drugs, particularly metformin, emerged as potent fibrosis inhibitors. Metformin attenuated fibrosis, improved renal function, and reduced inflammation and macrophage infiltration in the transplanted kidneys. These results provide new perspectives for understanding the complex molecular basis underlying transplanted renal fibrosis and developing novel therapeutic strategies.

Selective protein degradation through chaperone‑mediated autophagy: Implications for cellular homeostasis and disease (Review)

Cells rely on autophagy for the degradation and recycling of damaged proteins and organelles. Chaperone-mediated autophagy (CMA) is a selective process targeting proteins for degradation through the coordinated function of molecular chaperones and the lysosome‑associated membrane protein‑2A receptor (LAMP2A), pivotal in various cellular processes from signal transduction to the modulation of cellular responses under stress. In the present review, the intricate regulatory mechanisms of CMA were elucidated through multiple signaling pathways such as retinoic acid receptor (RAR)α, AMP‑activated protein kinase (AMPK), p38‑TEEB‑NLRP3, calcium signaling‑NFAT and PI3K/AKT, thereby expanding the current understanding of CMA regulation. A comprehensive exploration of CMA's versatile roles in cellular physiology were further provided, including its involvement in maintaining protein homeostasis, regulating ferroptosis, modulating metabolic diversity and influencing cell cycle and proliferation. Additionally, the impact of CMA on disease progression and therapeutic outcomes were highlighted, encompassing neurodegenerative disorders, cancer and various organ‑specific diseases. Therapeutic strategies targeting CMA, such as drug development and gene therapy were also proposed, providing valuable directions for future clinical research. By integrating recent research findings, the present review aimed to enhance the current understanding of cellular homeostasis processes and emphasize the potential of targeting CMA in therapeutic strategies for diseases marked by CMA dysfunction.

Potential Signal Pathways and Therapeutic Effects of Mesenchymal Stem Cell on Oxidative Stress in Diseases

Oxidative stress is a biological stress response produced by the destruction of redox equilibrium in aerobic metabolism in organisms, which is closely related to the occurrence of many diseases. Mesenchymal stem cells (MSCs) have been found to improve oxidative stress injury in a variety of diseases, including lung injury, liver diseases, atherosclerotic diseases, diabetes and its complications, ischemia-reperfusion injury, inflammatory bowel disease. The antioxidant stress capacity of MSCs may be a breakthrough in the treatment of these diseases. This review found that MSCs have the ability to resist oxidative stress, which may be achieved through MSCs involvement in mediating the Nrf2, MAPK, NF-κB, AMPK, PI3K/AKT and Wnt4/β-catenin signaling pathways.

CAPE activates AMPK and Foxo3 signaling to induce growth inhibition and ferroptosis in triple-negative breast cancer

PURPOSE

Approximately 20% of all breast cancer cases are classified as triple-negative breast cancer (TNBC), which represents the most challenging subtype due to its poor prognosis and high metastatic rate. Caffeic acid phenethyl ester (CAPE), the main component extracted from propolis, has been reported to exhibit anticancer activity across various tumor cell types. This study aimed to investigate the effects and mechanisms of CAPE on TNBC.

METHODS

MDA-MB-231 and MDA-MB-468 cells were treated with CAPE. CCK8 and colony formation assays were performed to analyze cell proliferation. Western blot, TUNEL and Annexin V-FITC/PI staining methods were employed to assess cell apoptosis. ROS, MDA, SOD, GSH, C11-bodipy staining, along with measurements of GPX4 and Ferritin levels, were utilized for ferroptosis detection. Western blot and immunofluorescence analysis were used to assess key regulatory molecules. The cells were subjected to treatments involving ferroptosis inhibition, AMPK inhibition, or Foxo3 inhibition, followed by CAPE administration to assess cell proliferation, apoptosis, and ferroptosis. Tumor xenografts were used to evaluate the antitumor efficacy of CAPE.

RESULTS

CAPE not only suppressed cell proliferation but also promoted apoptosis followed by ferroptosis. Co-incubation with Fer-1 (a ferroptosis inhibitor) diminished CAPE's suppressive effects on proliferation and apoptosis induction. CAPE treatment enhanced the phosphorylation of AMPK and promoted the nuclear translocation of Foxo3. Inhibition of both AMPK and Foxo3 by siRNAs or inhibitors (Compc, TIC10) reversed the growth retardation induced by CAPE as well as its pro-apoptotic effects leading to ferroptosis. Specifically, AMPK inhibition abrogated the CAPE-induced nuclear translocation of Foxo3. CAPE significantly inhibited tumor growth in nude mice bearing TNBC xenografts.

CONCLUSION

CAPE possesses a resistance effect on TNBC via activation of AMPK and Foxo3 signaling pathways.

AMP kinase: A promising therapeutic drug target for post-COVID-19 complications

The COVID-19 pandemic, caused by SARS-CoV-2, has resulted in severe respiratory issues and persistent complications, particularly affecting glucose metabolism. Patients with or without pre-existing diabetes often experience worsened symptoms, highlighting the need for innovative therapeutic approaches. AMPK, a crucial regulator of cellular energy balance, plays a pivotal role in glucose metabolism, insulin sensitivity, and inflammatory responses. AMPK activation, through allosteric or kinase-dependent mechanisms, impacts cellular processes like glucose uptake, fatty acid oxidation, and autophagy. The tissue-specific distribution of AMPK emphasizes its role in maintaining metabolic homeostasis throughout the body. Intriguingly, SARS-CoV-2 infection inhibits AMPK, contributing to metabolic dysregulation and post-COVID-19 complications. AMPK activators like capsaicinoids, curcumin, phytoestrogens, cilostazol, and momordicosides have demonstrated the potential to regulate AMPK activity. Compounds from various sources improve fatty acid oxidation and insulin sensitivity, with metformin showing opposing effects on AMPK activation compared to the virus, suggesting potential therapeutic options. The diverse effects of AMPK activation extend to its role in countering viral infections, further highlighting its significance in COVID-19. This review explores AMPK activation mechanisms, its role in metabolic disorders, and the potential use of natural compounds to target AMPK for post-COVID-19 complications. Also, it aims to review the possible methods of activating AMPK to prevent post-COVID-19 diabetes and cardiovascular complications. It also explores the use of natural compounds for their therapeutic effects in targeting the AMPK pathways. Targeting AMPK activation emerges as a promising avenue to mitigate the long-term effects of COVID-19, offering hope for improved patient outcomes and a better quality of life.

Potential mechanisms of rheumatoid arthritis therapy: Focus on macrophage polarization

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that affects multiple organs and systems in the human body, often leading to disability. Its pathogenesis is complex, and the long-term use of traditional anti-rheumatic drugs frequently results in severe toxic side effects. Therefore, the search for a safer and more effective antirheumatic drug is extremely important for the treatment of RA. As important immune cells in the body, macrophages are polarized. Under pathological conditions, macrophages undergo proliferation and are recruited to diseased tissues upon stimulation. In the local microenvironment, they polarize into different types of macrophages in response to specific factors and perform unique functions and roles. Previous studies have shown that there is a link between macrophage polarization and RA, indicating that certain active ingredients can ameliorate RA symptoms through macrophage polarization. Notably, Traditional Chinese medicine (TCM) monomer component and compounds demonstrate a particular advantage in this process. Building upon this insight, we reviewed and analyzed recent studies to offer valuable and meaningful insights and directions for the development and application of anti-rheumatic drugs.

The role of the interplay between macrophage glycolytic reprogramming and NLRP3 inflammasome activation in acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a severe respiratory condition associated with elevated morbidity and mortality. Understanding their complex pathophysiological mechanisms is crucial for developing new preventive and therapeutic strategies. Recent studies highlight the significant role of inflammation involved in ALI/ARDS, particularly the hyperactivation of the NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome in macrophages. This activation drives pulmonary inflammation by releasing inflammatory signalling molecules and is linked to metabolic reprogramming, marked by increased glycolysis and reduced oxidative phosphorylation. However, the relationship between NLRP3 inflammasome activation and macrophage glycolytic reprogramming in ALI/ARDS, as well as the molecular mechanisms regulating these processes, remain elusive. This review provides a detailed description of the interactions and potential mechanisms linking NLRP3 inflammasome activation with macrophage glycolytic reprogramming, proposing that glycolytic reprogramming may represent a promising therapeutic target for mitigating inflammatory responses in ALI/ARDS. KEY POINTS: NLRP3 inflammasome activation is pivotal in mediating the excessive inflammatory response in ALI/ARDS. Glycolytic reprogramming regulates NLRP3 inflammasome activation. Therapeutic potential of targeting glycolytic reprogramming to inhibit NLRP3 inflammasome activation in ALI/ARDS.

PDE4B abrogation extenuates angiotensin II-induced endothelial dysfunction related to hypertension through up-regulation of AMPK/Sirt1/Nrf2/ARE signaling

Endothelial dysfunction is commonly perceived as a precursor in the process of hypertension, a severe cardiovascular disorder. Phosphodiesterase 4B (PDE4B) inactivation has been proposed to exert cardioprotective effects and prevent pulmonary hypertension. However, the role of PDE4B in endothelial dysfunction in hypertension remains inexplicit, which will be investigated in the present work. In angiotensin II (Ang II)-induced human umbilical vein endothelial cells (HUVECs), RT-qPCR and Western blotting were used to analyze PDE4B expression. CCK-8 method was used to detect cell viability. Flow cytometry assay and Caspase 3 assay kit were used to detect cellular apoptotic level. Wound healing and tube formation assays were respectively used to detect cell migration and angiogenesis. Western blotting and corresponding assay kits were respectively used to analyze the expressions and contents of endothelial dysfunction markers. JC-1 assay, RT-qPCR and relevant assay kit were respectively used to detect mitochondrial membrane potential (ΔΨm), quantify mitochondrial DNA (mtDNA) copy number and mitochondrial permeability transition pore (mPTP) opening. Besides, Western blotting was used to analyze the expressions of endoplasmic reticulum stress (ERS) and AMP-activated protein kinase (AMPK)/sirtuin 1 (Sirt1)/nuclear factor-erythroid 2 related factor 2 (Nrf2)/antioxidant response element (ARE) signaling-associated proteins. PDE4B expression was increased in Ang II- induced HUVECs. PDE4B knockdown promoted the viability, migration, angiogenesis while inhibiting the apoptosis, endothelial dysfunction, ERS and mitochondrial damage in Ang II-induced HUVECs. Additionally, PDE4B silence activated AMPK/Sirt1/Nrf2/ARE pathway and AMPK inhibitor Compound C (CC) partially reversed the effects of PDE4B down-regulation on Ang II-induced HUVECs. Conclusively, PDE4B inhibition might protect against Ang II-induced endothelial dysfunction in HUVECs via up-regulating AMPK/Sirt1/Nrf2/ARE pathway, which might be mediated by the suppression of ERS and mitochondrial damage.

Activation of the LKB1/AMPK/HIF-1α Pathway by Metformin to Promote Neovascularisation in Cerebral Ischaemia

As a difficult-to-treat neurological condition, cerebral ischemia is currently limited to treatments such as intravenous recombinant tissue plasminogen activator thrombolysis and thrombectomy. Metformin, a potent antidiabetic drug, has been reported to have an independent function in enhancing the prognosis of stroke patients, in addition to its glucose-lowering effects. However, the mechanism of action of metformin in this context remains unclear. In vivo, a rat model of permanent middle cerebral artery occlusion was established, and after administration of a low dose of 10.5 mg/mL metformin, infarct area was measured by TTC staining, and cortical blood flow was determined by laser Doppler imaging. In vitro, the study established human umbilical vein endothelial cells treated with cobalt chloride. Immunofluorescence, immunohistochemistry, and Western blot experiments were performed to observe the expression of angiogenic factors, tight junction proteins, and apoptotic factors. A TUNEL assay was utilized to appraise cell death by apoptosis. A tube formation assay and scratch assay were conducted to determine the endothelial neovascularization status. Animal experiments have revealed that the administration of the AMPK activator metformin significantly reduced the infarct area, promoted the expression of angiogenic factors, and maintained the stability of tight junction proteins in endothelial cells. Moreover, metformin reduces nerve cells apoptosis by affecting the expression of the apoptotic protein cleaved-caspase3 via the HIF-1α pathway. In vitro, the LKB1/AMPK signaling pathway is activated after hypoxic stimulation, attaining its peak within the early stages of hypoxia (1-12 h) and gradually weakening thereafter. The administration of AMPK pharmacological agonists (between 36 and 48 h) can enhance AMPK activity, which can lead to the expression of angiogenic factors, maintain the stability of tight-junction proteins in endothelial cells, and facilitate endothelial cell migration and vascular structure formation. Conversely, the AMPK inhibitors exert the opposite effects. The activation of the LKB1/AMPK/HIF-1α signaling pathway by metformin in cerebral ischemia contributes to angiogenesis, promotes tissue repair in the injured area, and enhances neurologically functional symptoms.

The metabolic sensor AMPK: Twelve enzymes in one

BACKGROUND

AMP-activated protein kinase (AMPK) is an evolutionarily conserved regulator of energy metabolism. AMPK is sensitive to acute perturbations to cellular energy status and leverages fundamental bioenergetic pathways to maintain cellular homeostasis. AMPK is a heterotrimer comprised of αβγ-subunits that in humans are encoded by seven individual genes (isoforms α1, α2, β1, β2, γ1, γ2 and γ3), permitting formation of at least 12 different complexes with personalised biochemical fingerprints and tissue expression patterns. While the canonical activation mechanisms of AMPK are well-defined, delineation of subtle, as well as substantial, differences in the regulation of heterogenous AMPK complexes remain poorly defined.

SCOPE OF REVIEW

Here, taking advantage of multidisciplinary findings, we dissect the many aspects of isoform-specific AMPK function and links to health and disease. These include, but are not limited to, allosteric activation by adenine nucleotides and small molecules, co-translational myristoylation and post-translational modifications (particularly phosphorylation), governance of subcellular localisation, and control of transcriptional networks. Finally, we delve into current debate over whether AMPK can form novel protein complexes (e.g., dimers lacking the α-subunit), altogether highlighting opportunities for future and impactful research.

MAJOR CONCLUSIONS

Baseline activity of α1-AMPK is higher than its α2 counterpart and is more sensitive to synergistic allosteric activation by metabolites and small molecules. α2 complexes however, show a greater response to energy stress (i.e., AMP production) and appear to be better substrates for LKB1 and mTORC1 upstream. These differences may explain to some extent why in certain cancers α1 is a tumour promoter and α2 a suppressor. β1-AMPK activity is toggled by a 'myristoyl-switch' mechanism that likely precedes a series of signalling events culminating in phosphorylation by ULK1 and sensitisation to small molecules or endogenous ligands like fatty acids. β2-AMPK, not entirely beholden to this myristoyl-switch, has a greater propensity to infiltrate the nucleus, which we suspect contributes to its oncogenicity in some cancers. Last, the unique N-terminal extensions of the γ2 and γ3 isoforms are major regulatory domains of AMPK. mTORC1 may directly phosphorylate this region in γ2, although whether this is inhibitory, especially in disease states, is unclear. Conversely, γ3 complexes might be preferentially regulated by mTORC1 in response to physical exercise.

Current Challenges and Future Directions in the Assessment of Glucocorticoid Status

Glucocorticoid (GC) hormones are secreted in a circadian and ultradian rhythm and play a critical role in maintaining physiological homeostasis, with both excess and insufficient GC associated with adverse effects on health. Current assessment of GC status is primarily clinical, often in conjunction with serum cortisol values, which may be stimulated or suppressed depending on the GC disturbance being assessed. In the setting of extreme perturbations in cortisol levels ie, markedly low or high levels, symptoms and signs of GC dysfunction may be overt. However, when disturbances in cortisol GC status values are less extreme, such as when assessing optimization of a GC replacement regimen, signs and symptoms can be more subtle or nonspecific. Current tools for assessing GC status are best suited to identifying profound disturbances but may lack sensitivity for confirming optimal GC status. Moreover, single cortisol values do not necessarily reflect an individual's GC status, as they are subject to inter- and intraindividual variation and do not take into account the pulsatile nature of cortisol secretion, variation in binding proteins, or local tissue concentrations as dictated by 11beta-hydroxysteroid dehydrogenase activity, as well as GC receptor sensitivity. In the present review, we evaluate possible alternative methods for the assessment of GC status that do not solely rely on the measurement of circulating cortisol levels. We discuss the potential of changes in metabolomic profiles, micro RNA, gene expression, and epigenetic and other novel biomarkers such as growth differentiating factor 15 and osteocalcin, which could in the future aid in the objective classification of GC status.

Naphthoquinone-derived ZSW-4B induces apoptosis in triple-negative breast cancer via AMPK signalling activation

Triple-negative breast cancer (TNBC) is the most malignant molecular subtype of breast cancer and is characterized by aggressiveness, high mortality, significant heterogeneity, and poor prognosis. AMPK plays a critical role in maintaining the cellular energy balance, and its inactivation is associated with malignant breast cancer. Here, we identified the pharmacological mechanism of the 1,4-naphthoquinone derivative ZSW-4B. MTT, colony formation, and nude mouse xenograft tumour models demonstrated that ZSW-4B selectively inhibits the proliferation of TNBC cells both in vitro and in vivo. Flow cytometry and Western blot analysis revealed that ZSW-4B induces apoptosis in TNBC cells. Phosphoproteomic analysis revealed activation of the AMPK signalling pathway by ZSW-4B. Additionally, the application of the CRISPR-Cas9 system to genetically knockout AMPK in TNBC cell lines was demonstrated to reverse the antitumour effects elicited by ZSW-4B both in vitro and in vivo. In summary, ZSW-4B inhibits TNBC by inducing cellular apoptosis through the activation of AMPK.

Protective Role of Cepharanthine Against Equid Herpesvirus Type 8 Through AMPK and Nrf2/HO-1 Pathway Activation

Equid herpesvirus type 8 (EqHV-8) is known to cause respiratory disease and miscarriage in horses and donkeys, which is a major problem for the equine farming industry. However, there are currently limited vaccines or drugs available to effectively treat EqHV-8 infection. Therefore, it is crucial to develop new antiviral approaches to prevent potential pandemics caused by EqHV-8. This study evaluates the antiviral and antioxidant effects of cepharanthine against EqHV-8 by employing both in vitro assays and in vivo mouse models to assess its therapeutic efficacy. To assess the effectiveness of cepharanthine against EqHV-8, we conducted experiments using NBL-6 and RK-13 cells. Additionally, we developed a mouse model to validate cepharanthine's effectiveness against EqHV-8. In our in vitro experiments, we assessed the cepharanthine's ability to inhibit infection caused by EqHV-8 in NBL-6 and RK-13 cells. Our results demonstrated that cepharanthine has a dose-dependent inhibitory effect, indicating that it possesses anti-EqHV-8 properties at the cellular level. Moreover, we investigated the mechanism through which cepharanthine exerts its protective effects. It was observed that cepharanthine effectively reduces the oxidative stress induced by EqHV-8 by activating the AMPK and Nrf2/HO-1 signaling pathways. Furthermore, when administered to EqHV-8 infected mice, cepharanthine significantly improved lung tissue pathology and reduced oxidative stress. The findings presented herein collectively highlight cepharanthine as a promising candidate for combating EqHV-8 infections.

Predicting binding events in very flexible, allosteric, multi-domain proteins

Knowledge of the structures formed by proteins and small molecules is key to understand the molecular principles of chemotherapy and for designing new and more effective drugs. During the early stage of a drug discovery program, it is customary to predict ligand-protein complexes in silico, particularly when screening large compound databases. While virtual screening based on molecular docking is widely used for this purpose, it generally fails in mimicking binding events associated with large conformational changes in the protein, particularly when the latter involve multiple domains. In this work, we describe a new methodology to generate bound-like conformations of very flexible and allosteric proteins bearing multiple binding sites by exploiting only information on the unbound structure and the putative binding sites. The protocol is validated on the paradigm enzyme adenylate kinase, for which we generated a significant fraction of bound-like structures. A fraction of these conformations, employed in ensemble-docking calculations, allowed to find native-like poses of substrates and inhibitors (binding to the active form of the enzyme), as well as catalytically incompetent analogs (binding the inactive form). Our protocol provides a general framework for the generation of bound-like conformations of challenging drug targets that are suitable to host different ligands, demonstrating high sensitivity to the fine chemical details that regulate protein's activity. We foresee applications in virtual screening, in the prediction of the impact of amino acid mutations on structure and dynamics, and in protein engineering.

Oxyberberine Inhibits Hepatic Gluconeogenesis via AMPK-Mediated Suppression of FoxO1 and CRTC2 Signaling Axes

Oxyberberine (OBB), a natural metabolite of berberine, has been shown to exhibit inhibitory effects on gluconeogenesis in our previous work. This work was designed to investigate the potential effects and underlying mechanisms of OBB on hepatic gluconeogenesis. Our work found that OBB significantly inhibited the expressions of glucose 6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK), and decreased the glucose production in palmitic acid-induced HepG2 cells. Then, AMPK/Akt/FoxO1 and AMPK/CRTC2 signaling pathways were confirmed by transcriptomics and network pharmacology analyses. It was shown that AMPK activation may phosphorylate and promote nuclear exclusion of FoxO1 and CRTC2, two key regulators of hepatic gluconeogenesis transcriptional pathways, resulting in the inhibition of gluconeogenesis under OBB administration. Afterwards, AMPK/Akt/FoxO1, AMPK/CRTC2 signaling pathways were evidenced by western blot, immunoprecipitation and confocal immunofluorescence, and the targeted inhibitor (Compound C) and siRNA of AMPK were applied for further mechanism verification. Moreover, it was found that OBB treatment activated AMPK/Akt/FoxO1 and AMPK/CRTC2 signaling pathways to decrease hepatic gluconeogenesis in db/db mice. Similarly, the in vivo inhibitory effects of OBB on gluconeogenesis were also diminished by AMPK inhibition. Our work demonstrated that OBB can inhibit hepatic gluconeogenesis in vitro and in vivo, and its underlying mechanisms were associated with AMPK-mediated suppression of FoxO1 and CRTC2 signaling axes.

Transcriptomics reveals the mechanism of terbuthylazine-induced nephrotoxicity in chickens: Insights from AMPK/p53-mediated apoptosis perspective

As a commonly used pesticide, the widespread use of terbuthylazine (TBA) may cause toxic effects in animals and human. However, the nephrotoxicity induced by TBA is unclear. Here, we explored the mechanism of TBA-induced nephrotoxicity through transcriptomics and molecular biology techniques in broilers. Pathologic analysis showed that TBA could cause renal cell vacuolation and fibrosis in broilers. Additionally, transcriptomic analysis showed that TBA can cause significant changes in the expression of some apoptosis-related genes, and GO and KEGG analysis also found that TBA can significantly change the functions of apoptosis pathway and AMPK signaling pathway in kidney. Subsequently, the protein expression levels of Bax, Bak-1, FADD, and cleaved Caspase-3/Caspase-3 were elevated significantly and the number of TUNEL-positive cells was increased markedly in kidney under TBA exposure. Meanwhile, we also found that TBA could activate AMPK/p53 pathway, as evidenced by the upregulated levels of AMPKα1 phosphorylation and protein expression of p53. Therefore, our results suggested that TBA could induce apoptosis via AMPK/p53 pathway in kidney. These findings identified the nephrotoxic mechanism of TBA through transcriptomics, providing a new insight into TBA toxicology.

Gut microbiota-derived Metabolite, Shikimic Acid, inhibits vascular smooth muscle cell proliferation and migration

Gut microbiota dysbiosis is linked to vascular wall disease, but the mechanisms by which gut microbiota cross-talk with the host vascular cells remain largely unknown. Shikimic acid (SA) is a biochemical intermediate synthesized in plants and microorganisms, but not mammals. Surprisingly, recent metabolomic profiling data demonstrate that SA is detectable in human and murine blood. In this study, analyzing data from germ-free rats, we provide evidence in support of SA as a bona fide gut microbiota-derived metabolite, emphasizing its biological relevance. Since vascular cells are the first cells exposed to circulating metabolites, in this study, we examined, for the first time, the effects and potential underlying molecular mechanisms of SA on vascular smooth muscle cell (VSMC) proliferation and migration, which play a key role in occlusive vascular diseases, such as post-angioplasty restenosis and atherosclerosis. We found that SA inhibits the proliferation and migration of human coronary artery SMCs. At the molecular level, unexpectedly, we found that SA activates, rather than inhibits, multiple pro-mitogenic signaling pathways in VSMCs, such as ERK1/2, AKT, and mTOR/p70S6K. Conversely, we found that SA activates the anti-proliferative AMP-activated protein kinase (AMPK) in VSMCs, a key cellular energy sensor and regulator. However, loss-of-function experiments demonstrate that AMPK does not mediate the inhibitory effects of SA on VSMC proliferation. In conclusion, these studies demonstrate that a microbiota-derived metabolite, SA, inhibits VSMC proliferation and migration in vitro and prompt further evaluation of the possible underlying molecular mechanisms and the potential protective role in VSMC-related vascular wall disease in vivo.

"NO" controversy?: A controversial role in insulin signaling of diabetic encephalopathy

Insulin, a critical hormone in the human body, exerts its effects by binding to insulin receptors and regulating various cellular processes. While nitric oxide (NO) plays an important role in insulin secretion and acts as a mediator in the signal transduction pathway between upstream molecules and downstream effectors, holds a significant position in the downstream signal network of insulin. Researches have shown that the insulin-NO system exhibits a dual regulatory effect within the central nervous system, which is crucial in the regulation of diabetic encephalopathy (DE). Understanding this system holds immense practical importance in comprehending the targets of existing drugs and the development of potential therapeutic interventions. This review extensively examines the characterization of insulin, NO, Nitric oxide synthase (NOS), specific NO pathway, their interconnections, and the mechanisms underlying their regulatory effects in DE, providing a reference for new therapeutic targets of DE.

β-catenin-inhibited Sumoylation modification of LKB1 and fatty acid metabolism is critical in renal fibrosis

Liver kinase B1 (LKB1) is a serine/threonine kinase controlling cell homeostasis. Among post-translational modification, Sumoylation is vital for LKB1 activating adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), the key regulator in energy metabolism. Of note, AMPK-regulated fatty acid metabolism is highly involved in maintaining normal renal function. However, the regulative mechanisms of LKB1 Sumoylation remain elusive. In this study, we demonstrated that β-catenin, a notorious signal in renal fibrosis, inhibited the Sumoylation of LKB1, thereby disrupting fatty acid oxidation in renal tubular cells and triggering renal fibrosis. Mechanically, we found that Sumo3 was the key mediator for LKB1 Sumoylation in renal tubular cells, which was transcriptionally inhibited by β-catenin/Transcription factor 4 (TCF4) signaling. Overexpression of Sumo3, not Sumo1 or Sumo2, restored β-catenin-disrupted fatty acid metabolism, and retarded lipid accumulation and fibrogenesis in the kidney. In vivo, conditional knockout of β-catenin in tubular cells effectively preserved fatty acid oxidation and blocked lipid accumulation by maintaining LKB1 Sumoylation and AMPK activation. Furthermore, ectopic expression of Sumo3 strongly inhibited Wnt1-aggravated lipid accumulation and fibrogenesis in unilateral ischemia-reperfusion mice. In patients with chronic kidney disease, we found a loss of Sumo3 expression, and it was highly related to LKB1 repression. This contributes to fatty acid metabolism disruption and lipid accumulation, resulting in renal fibrosis. Overall, our study revealed a new mechanism in fatty acid metabolism dysfunction and provided a new therapeutic target pathway for regulating Sumo modification in renal fibrosis.

Pleiotropic role of CCR9/CCL25 signaling in adriamycin-induced cardiomyopathy

INTRODUCTION

Adriamycin (ADR)-induced cardiomyopathy is a common problem in many cancer survivors. Recently, specific chemokine receptors have garnered interest as therapeutic targets in cardiovascular diseases.

OBJECTIVES

This study aim to report the role of C-C chemokine receptor 9 (CCR9)/C-C chemokine ligand 25 (CCL25) and its therapeutic potential in ADR-induced cardiomyopathy.

METHODS

Functional gene knockout and overexpression mouse models were utilized to investigate the role of CCR9 against ADR-induced cardiomyopathy. Transcriptome sequencing was also performed to identify the downstream molecular mechanisms of CCR9.

RESULTS

This study revealed that CCR9 and CCL25 levels were increased in mice and HL-1 cells injured by ADR, consistent with the results of patients with heart failure. Both in vivo and in vitro, CCR9 overexpression overtly aggravated cardiac dysfunction, accompanied by decreased AMPK activity and increased mitochondrial dysfunction, fibrosis, oxidative stress, and apoptosis. However, the cardiac harmful effects of ADR were reserved by CCR9 knockdown, as well as CCR9 overexpression aggravated cardiotoxicity were reserved by AMPK agonist GSK621. By constructing different domain-missing CCR9 mutants, we suspected that the △4 region of CCR9 is important for AMPK activity. Furthermore, transcriptome sequencing  further illustrated the mechanism of CCR9 overexpression aggravated ADR-induced cardiotoxicity, which was associated with CYP1A1. Finally, lithospermic acid (LA) was screened and alleviated ADR-induced cardiotoxicity through regulation of CCR9/CCL25-AMPK signaling, bolstering CCR9-targeted potential clinical application.

CONCLUSION

These findings present a promising target and drug for treating chemotherapy-induced cardiotoxicity.

AdipoRon Alleviates Liver Injury by Protecting Hepatocytes from Mitochondrial Damage Caused by Ionizing Radiation

Radiation liver injury is a common complication of hepatocellular carcinoma radiotherapy. It is mainly caused by irreversible damage to the DNA of hepatocellular cells directly by radiation, which seriously interferes with metabolism and causes cell death. AdipoRon can maintain lipid metabolism and stabilize blood sugar by activating adiponectin receptor 1 (AdipoR1). However, the role of AdipoRon/AdipoR1 in the regulation of ionizing radiation (IR)-induced mitochondrial damage remains unclear. In this study, we aimed to elucidate the roles of AdipoRon/AdipoR1 in IR-induced mitochondrial damage in normal hepatocyte cells. We found that AdipoRon treatment rescued IR-induced liver damage in mice and mitochondrial damage in normal hepatocytes in vivo and in vitro. AdipoR1 deficiency exacerbated IR-induced oxidative stress, mitochondrial dynamics, and biogenesis disorder. Mechanistically, the absence of AdipoR1 inhibits the activity of adenosine monophosphate-activated protein kinase α (AMPKα), subsequently leading to disrupted mitochondrial dynamics by decreasing mitofusin (MFN) and increasing dynamin-related protein 1 (DRP1) protein expression. It also controls mitochondrial biogenesis by suppressing the peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC1α) and transcription factor A (TFAM) signaling pathway, ultimately resulting in impaired mitochondrial function. To sum up, AdipoRon/AdipoR1 maintain mitochondrial function by regulating mitochondrial dynamics and biogenesis through the AdipoR1-AMPKα signaling pathway. This study reveals the significant role of AdipoR1 in regulating IR-induced mitochondrial damage in hepatocytes and offers a novel approach to protecting against damage caused by IR.

Bioenergetic-active exosomes for cartilage regeneration and homeostasis maintenance

Cartilage regeneration relies on adequate and continuous bioenergy supply to facilitate cellular differentiation and extracellular matrix synthesis. Chondrocytes frequently undergo energy stress under pathological conditions, characterized by disrupted cellular metabolism and reduced adenosine triphosphate (ATP) levels. However, there has limited progress in modulating energy metabolism for cartilage regeneration thus far. Here, we developed bioenergetic-active exosomes (Suc-EXO) to promote cartilage regeneration and homeostasis maintenance. Suc-EXO exhibited a 5.42-fold increase in ATP content, enabling the manipulation of cellular energy metabolism by fueling the TCA cycle. With continuous energy supply, Suc-EXO promoted BMSC chondrogenic differentiation via the P2X7-mediated PI3K-AKT pathway. Moreover, Suc-EXO improved chondrocyte anabolism and mitochondrial homeostasis via the P2X7-mediated SIRT3 pathway. In a rabbit cartilage defect model, the Suc-EXO-encapsulated hydrogel notably promoted cartilage regeneration and maintained neocartilage homeostasis, leading to 2.26 and 1.53 times increase in Col2 and ACAN abundance, respectively. These findings make a remarkable breakthrough in modulating energy metabolism for cartilage regeneration, offering immense potential for clinical translation.

Amelioration of hyperuricemia by cordycepin and Cordyceps militaris aqueous extract in mice via modulating gut microbiota and restoring metabolic profile

In this study, we first screened and evaluated the inhibitory effects of seven medicinal fungi on diseases such as hyperuricemia (HUA). Then, using metabolomics and gut microbiome methods, the focus was on analyzing and evaluating the effects of the aqueous extract of Cordyceps. militaris (CME) and cordycepin on potassium oxyzinate induced HUA mice. It was found that CME exhibits good uric acid lowering activity in both in vivo and in vitro experiments. It can relieve hyperuricemia by inhibiting xanthine oxidase enzyme activity, reducing the production of xanthine precursors, and inhibiting insulin resistance. The uric acid-lowering efficacy of cordycepin in vivo is comparable to that of CME. The species abundance of Oscillibacter, Alistipes, Prevotellaaceae_NK3B31, Lachnospiraceae_NK4A136 were decreased after treatment with CME and cordycepin. The metabolomics analysis of cecal contents and fecal samples elucidated the mechanism of intervention of CME on hyperuricemia from different perspectives. This suggests that we should consider carefully when selecting samples. This current research provides the scientific foundation for the medicinal research of C. militaris and the maintenance of human health.

Leonurine Inhibits Hepatic Lipid Synthesis to Ameliorate NAFLD via the ADRA1a/AMPK/SCD1 Axis

Leonurine is a natural product unique to the Lamiaceae plant Leonurus japonicus Houtt., and it has attracted attention due to its anti-oxidative stress, anti-apoptosis, anti-fibrosis, and metabolic regulation properties. Also, it plays an important role in the prevention and treatment of nonalcoholic fatty liver disease (NAFLD) through a variety of biological mechanisms, but its mechanism of action remains to be elucidated. Therefore, this study aims to preliminarily explore the mechanisms of action of leonurine in NAFLD. Mice were randomly divided into four groups: the normal control (NC) group, the Model (M) group, the leonurine treatment (LH) group, and the fenofibrate treatment (FB) group. The NAFLD model was induced by a high-fat high-sugar diet (HFHSD) for 12 weeks, and liver pathological changes and biochemical indices were observed after 12 weeks. Transcriptomic analysis results indicated that leonurine intervention reversed the high-fat high-sugar diet-induced changes in lipid metabolism-related genes such as stearoyl-CoA desaturase 1 (Scd1), Spermine Synthase (Sms), AP-1 Transcription Factor Subunit (Fos), Oxysterol Binding Protein Like 5 (Osbpl5), and FK506 binding protein 5 (Fkbp5) in liver tissues. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis results suggest that leonurine may exert its lipid-lowering effects through the AMP-activated protein kinase (AMPK) signaling pathway. Liver lipidomic analysis showed that leonurine could alter the abundance of lipid molecules related to fatty acyl (FAs) and glycerophospholipids (GPs) such as TxB3, carnitine C12-OH, carnitine C18:1-OH, and LPC (20:3/0:0). Molecular biology experiments and molecular docking techniques verified that leonurine might improve hepatic lipid metabolism through the alpha-1A adrenergic receptor (ADRA1a)/AMPK/SCD1 axis. In summary, the present study explored the mechanism by which leonurine ameliorated NAFLD by inhibiting hepatic lipid synthesis via the ADRA1a/AMPK/SCD1 axis.

Canola Oil Ameliorates Obesity by Suppressing Lipogenesis and Reprogramming the Gut Microbiota in Mice via the AMPK Pathway

BACKGROUND

obesity is a worldwide problem that seriously endangers human health. Canola oil (Col) has been reported to regulate hepatic steatosis by influencing oxidative stress and lipid metabolism in Kunming mice. However, whether Col exhibits an anti-obesity effect by altering the gut microbiota remains unknown.

METHODS

in this study, we observed that a high-fat diet increased lipogenesis and gut microbiota disorder in C57BL/6J male mice, while the administration of Col suppressed lipogenesis and improved gut microbiota disorder.

RESULTS

the results show that Col markedly reduced the final body weight and subcutaneous adipose tissue of C57BL/6J male mice fed a high-fat diet (HFD) after 6 weeks of administration. However, although Col did not effectively increase the serum concentration of HDL, we found that treatment with Col notably inhibited the low-density lipoprotein (LDL), total cholesterol (TC), and triglycerides (TGs) in HFD mice. Furthermore, Col ameliorated obesity in the liver compared to mice that were only fed a high-fat diet. We also found that Col significantly inhibited the relative expression of sterol regulatory element binding protein (SREBP1/2), peroxisome proliferator-activated receptor γ (PPARγ), and insulin-induced genes (Insig1/2) that proved to be closely associated with lipogenesis in HFD mice. In addition, the concentration of acetic acid was significantly increased in Col-treatment HFD mice. Further, we noted that Col contributed to the reprogramming of the intestinal microbiota. The relative abundances of Akkermansia, Dubosiella, and Alistipes were enhanced under treatment with Col in HFD mice. The results also imply that Col markedly elevated the phosphorylation level of the AMP-activated protein kinase (AMPK) pathway in HFD mice.

CONCLUSIONS

the results of our study show that Col ameliorates obesity and suppresses lipogenesis in HFD mice. The underlying mechanisms are possibly associated with the reprogramming of the gut microbiota, in particular, the acetic acid-mediated increased expression of Alistipes via the AMPK signaling pathway.

Targeting the autophagy-miRNA axis in prostate cancer: toward novel diagnostic and therapeutic strategies

Since prostate cancer is one of the leading causes of cancer-related death, a better understanding of the molecular pathways guiding its development is imperative. A key factor in prostate cancer is autophagy, a cellular mechanism that affects both cell survival and death. Autophagy is essential in maintaining cellular homeostasis. Autophagy is a physiological mechanism wherein redundant or malfunctioning cellular constituents are broken down and recycled. It is essential for preserving cellular homeostasis and is implicated in several physiological and pathological conditions, including cancer. Autophagy has been linked to metastasis, tumor development, and treatment resistance in prostate cancer. The deregulation of miRNAs related to autophagy appears to be a crucial element in the etiology of prostate cancer. These miRNAs influence the destiny of cancer cells by finely regulating autophagic mechanisms. Numerous investigations have emphasized the dual function of specific miRNAs in prostate cancer, which alter autophagy-related pathways to function as either tumor suppressors or oncogenes. Notably, miRNAs have been linked to the control of autophagy and the proliferation, apoptosis, and migration of prostate cancer cells. To create customized therapy approaches, it is imperative to comprehend the dynamic interplay between autophagy and miRNAs in prostate cancer. The identification of key miRNAs provides potential diagnostic and prognostic markers. Unraveling the complex network of lncRNAs, like PCA3, also expands the repertoire of molecular targets for therapeutic interventions. This review explores the intricate interplay between autophagy and miRNAs in prostate cancer, focusing on their regulatory roles in cellular processes ranging from survival to programmed cell death.

Przewaquinone A inhibits Angiotensin II-induced endothelial diastolic dysfunction activation of AMPK

BACKGROUND

Endothelial dysfunction (ED), characterized by markedly reduced nitric oxide (NO) bioavailability, vasoconstriction, and a shift toward a proinflammatory and prothrombotic state, is an important contributor to hypertension, atherosclerosis, and other cardiovascular diseases. Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is widely involved in cardiovascular development. Przewaquinone A (PA), a lipophilic diterpene quinone extracted from Salvia przewalskii Maxim, inhibits vascular contraction.

PURPOSE

Herein, the goal was to explore the protective effect of PA on ED in vivo and in vitro, as well as the underlying mechanisms.

METHODS

A human umbilical vein endothelial cell (HUVEC) model of ED induced by angiotensin II (AngII) was used for in vitro observations. Levels of AMPK, endothelial nitric oxide synthase (eNOS), vascular cell adhesion molecule-1 (VCAM-1), nitric oxide (NO), and endothelin-1 (ET-1) were detected by western blotting and ELISA. A mouse model of hypertension was established by continuous infusion of AngII (1000 ng/kg/min) for 4 weeks using osmotic pumps. Following PA and/or valsartan administration, NO and ET-1 levels were measured. The levels of AMPK signaling-related proteins in the thoracic aorta were evaluated by immunohistochemistry. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were measured using the tail cuff method. Isolated aortic vascular tone measurements were used to evaluate the vasodilatory function in mice. Molecular docking, molecular dynamics, and surface plasmon resonance imaging (SPRi) were used to confirm AMPK and PA interactions.

RESULTS

PA inhibited AngII-induced vasoconstriction and vascular adhesion as well as activated AMPK signaling in a dose-dependent manner. Moreover, PA markedly suppressed blood pressure, activated vasodilation in mice following AngII stimulation, and promoted the activation of AMPK signaling. Furthermore, molecular simulations and SPRi revealed that PA directly targeted AMPK. AMPK inhibition partly abolished the protective effects of PA against endothelial dysfunction.

CONCLUSION

PA activates AMPK and ameliorates endothelial dysfunction during hypertension.