AMP-activated protein kinase: an energy sensor that regulates all aspects of cell function

Investigation of Signaling in Primary Populations of Human Senescent T Cells

Mitogen-activated protein kinases, a family of three stress-related kinases, the Erks and Jnks and p38s, are activated by three-layer transphosphorylation cascades and are important for the activation, differentiation, and effector functions of lymphocytes. Recent studies on the aged immune systems from both humans and mice have uncovered a different mode of MAPK signaling that is independent of canonical activation cascades and instead occurs through simultaneous self-phosphorylation reactions within the sestrin-MAPK activation complex (sMAC), an immune-inhibitory complex not previously observed. In this chapter, we discuss methodologies to study these pathways at the population and single cell level, which allows rejuvenating immune cell differentiation and fate.

FBXL19 Targeted STK11 Degradation Enhances Cigarette Smoke-Induced Airway Epithelial Cell Cytotoxicity

Objective: To investigate the effects of cigarette smoke (CS) on Serine/Threonine Kinase 11 (STK11) and to determine STK11's role in CS-induced airway epithelial cell cytotoxicity.Methods: STK11 expression levels in the lung tissues of smokers with or without COPD and mice exposed to CS or room air (RA) were determined by immunoblotting and RT-PCR. BEAS-2Bs-human bronchial airway epithelial cells were exposed to CS extract (CSE), and the changes in STK11 expression levels were determined by immunoblotting and RT-PCR. BEAS-2B cells were transfected with STK11-specific siRNA or STK11 expression plasmid, and the effects of CSE on airway epithelial cell cytotoxicity were measured. To determine the specific STK11 degradation-proteolytic pathway, BEAS-2Bs were treated with cycloheximide alone or combined with MG132 or leupeptin. Finally, to identify the F-box protein mediating the STK11 degradation, a screening assay was performed using transfection with a panel of FBXL E3 ligase subunits.Results: STK11 protein levels were significantly decreased in the lung tissues of smokers with COPD relative to smokers without COPD. STK11 protein levels were also significantly decreased in mouse lung tissues exposed to CS compared to RA. Exposure to CSE shortened the STK11 mRNA and protein half-life to 4 h in BEAS-2B cells. STK11 protein overexpression attenuated the CSE-induced cytotoxicity; in contrast, its knockdown augmented CSE-induced cytotoxicity. FBXL19 mediates CSE-induced STK11 protein degradation via the ubiquitin-proteasome pathway in cultured BEAS-2B cells. FBXL19 overexpression led to accelerated STK11 ubiquitination and degradation in a dose-dependent manner.Conclusions: Our results suggest that CSE enhances the degradation of STK11 protein in airway epithelial cells via the FBXL19-mediated ubiquitin-proteasomal pathway, leading to augmented cell death.HIGHLIGHTSLung tissues of COPD-smokers exhibited a decreased STK11 RNA and protein expression.STK11 overexpression attenuates CS-induced airway epithelial cell cytotoxicity.STK11 depletion augments CS-induced airway epithelial cell cytotoxicity.CS diminishes STK11 via FBXL19-mediated ubiquitin-proteasome degradation.

Pelargonic acid's interaction with the auxin transporter PIN1: A potential mechanism behind its phytotoxic effects on plant metabolism

Pelargonic acid (PA) is a saturated fatty acid commonly found in several organisms, that is known for its phytotoxic effect and its use as bioherbicide for sustainable weed management. Although PA is already commercialised as bioherbicide, its molecular targets and mode of action is unknown according to the Herbicide Resistance Action Committee. Therefore, the aim of this work was focusing on the way this natural active substance impacts the plant metabolism of the model species Arabidopsis thaliana. PA caused increase of secondary and adventitious roots, as well as torsion, loss of gravitropism and phytotoxic effects. Moreover, PA altered the cellular arrangement and the PIN proteins activity. Computational simulations revealed that the intermolecular interactions between PA and the polar auxin transporter protein PIN1 are very similar to those established between the natural auxin IAA and PIN1. However, under intracellular conditions, the PA-PIN1 binding is more energetically stable than the IAA-PIN1. These results suggest that PA could act as an auxin-mimics bioherbicide. The exogenous application of PA would be responsible for the alterations observed both at structural and ultrastructural levels, which would be caused by the alteration on the transport of auxins into the plant, inducing root inhibition and ultimately total stop of root growth.

Moderate embryonic delay of paternal mitochondrial elimination impairs mating and cognition and alters behaviors of adult animals

Rapid elimination of paternal mitochondria following fertilization is a conserved event in most animals, but its physiological significance remains unclear. We find that modest delay of paternal mitochondrial elimination (PME) in Caenorhabditis elegans embryos unexpectedly impairs mating and cognition of adult animals and alters their locomotion behaviors. Delayed PME causes decreased adenosine triphosphate (ATP) levels in early embryos, which lead to impaired physiological functions of adult animals through an energy-sensing pathway mediated by an adenosine monophosphate (AMP)-activated protein kinase, AAK-2, and a forkhead box class O (FOXO) transcription factor, DAF-16. Treatment of PME-delayed animals with MK-4, a subtype of vitamin K2 that can improve mitochondrial ATP production, restores ATP levels in early embryos, and rescues physiological defects of adult animals. Our results suggest that moderate PME delay during embryo development adversely affects crucial physiological functions in adults, which could be evolutionarily disadvantageous. These observations provide mechanistic explanations for the need to swiftly remove paternal mitochondria early during embryo development.

The paradox of autophagy in cancer: NEAT1's role in tumorigenesis and therapeutic resistance

Cancer remains a current active problem of modern medicine, a process during which cell growth and proliferation become uncontrolled. However, the role of autophagy in the oncological processes is counterintuitive and, at the same time, increasingly influential on the formation, development, and response to therapy of oncological diseases. Autophagy is a vital cellular process that removes defective proteins and organelles and supports cellular homeostasis. Autophagy can enhance the ability to form new tumors and suppress this formation in cancer. The dual potential of apoptosis may be the reason for this duality in either promoting or impeding the survival of cancer cells, depending on the situation, including starvation or treatment stress. Furthermore, long non-coding RNA NEAT1, which has been linked to several stages of carcinogenesis and in all forms of the illness, has drawn attention as a major player in cancer biology. NEAT1 is a structural portion of nuclear paraspeckles and has roles in deactivating expression in both transcriptional and post-transcriptional levels. NEAT1 acts in carcinogenesis in numerous ways, comprising interactions with microRNAs, the influence of gene articulation, regulation of epigenetics, and engagement in signalling cascades. In addition, the complexity of NEAT1's role in cancer occurrence is amplified by its place in regulating cancer stem cells and the tumor microenvironment. NEAT1's interaction with autophagy further complicates the already complicated function of this RNA in cancer biology. NEAT1 has been linked to autophagy in several types of cancer, influencing autophagy pathways and altering its stress response and tumor cell viability. Understanding the interrelation between NEAT1, autophagy, and cancer will enable practitioners to identify novel treatment targets and approaches to disrupt oncogenic processes, reduce the occurrence of treatment resistance, and increase patient survival rates. Specialized treatment strategies and regimens are thus achievable. In the present review, the authors analyze sophisticated relationship schemes in cancer: The NEAT1 pathway and the process of autophagy.

Complex Interplay Between Metabolism and CD4+ T-Cell Activation, Differentiation, and Function: a Novel Perspective for Atherosclerosis Immunotherapy

Atherosclerosis is a complex pathological process that results from the chronic inflammatory reaction of the blood vessel wall and involves various immune cells and cytokines. An imbalance in the proportion and function of the effector CD4+ T-cell (Teff) and regulatory T-cell (Treg) subsets is an important cause of the occurrence and development of atherosclerotic plaques. Teff cells depend on glycolytic metabolism and glutamine catabolic metabolism for energy, while Treg cells mainly rely on fatty acid oxidation (FAO), which is crucial for determining the fate of CD4+ T cells during differentiation and maintaining their respective immune functions. Here, we review recent research achievements in the field of immunometabolism related to CD4+ T cells, focusing on the cellular metabolic pathways and metabolic reprogramming involved in the activation, proliferation, and differentiation of CD4+ T cells. Subsequently, we discuss the important roles of mTOR and AMPK signaling in regulating CD4+ T-cell differentiation. Finally, we evaluated the links between CD4+ T-cell metabolism and atherosclerosis, highlighting the potential of targeted modulation of CD4+ T-cell metabolism in the prevention and treatment of atherosclerosis in the future.

Development of a Dual Reporter System to Simultaneously Visualize Ca2+ Signals and AMPK Activity

In this study, we introduce a new separation of phases-based activity reporter of kinase (SPARK) for AMP-activated kinase (AMPK), named AMPK-SPARK, which reports the AMPK activation by forming bright fluorescent clusters. Furthermore, we introduce a dual reporter system, named GCaMP-AMPK-SPARK, by incorporating a single-fluorescent protein (FP)-based Ca2+ biosensor, GCaMP6f, into our initial design, enabling simultaneous monitoring of Ca2+ levels and AMPK activity. This system offers the essential quality of information by single-channel fluorescence microscopy without the need for coexpression of different biosensors and elaborate filter layouts to overcome spectral limitations. We used AMPK-SPARK to map endogenous AMPK activity in different cell types and visualized the dynamics of AMPK activation in response to various stimuli. Using GCaMP-AMPK-SPARK, we revealed cell-to-cell heterogeneities in AMPK activation by Ca2+ mobilization. We anticipate that this dual reporter strategy can be employed to study the intricate interplays between different signaling networks and kinase activities.

AMPK and O-GlcNAcylation: interplay in cardiac pathologies and heart failure

Heart failure (HF) represents a multifaceted clinical syndrome characterized by the heart's inability to pump blood efficiently to meet the body's metabolic demands. Despite advances in medical management, HF remains a major cause of morbidity and mortality worldwide. In recent years, considerable attention has been directed toward understanding the molecular mechanisms underlying HF pathogenesis, with a particular focus on the role of AMP-activated protein kinase (AMPK) and protein O-GlcNAcylation. This review comprehensively examines the current understanding of AMPK and O-GlcNAcylation signalling pathways in HF, emphasizing their interplay and dysregulation. We delve into the intricate molecular mechanisms by which AMPK and O-GlcNAcylation contribute to cardiac energetics, metabolism, and remodelling, highlighting recent preclinical and clinical studies that have explored novel therapeutic interventions targeting these pathways.

Metabolic regulation of preimplantation embryo development in vivo and in vitro: Molecular mechanisms and insights

Understanding of embryonic development has led to the clinical application of Assisted Reproductive technologies (ART), with the resulting birth of millions of children. Recent developments in metabolomics, proteomics, and transcriptomics have brought to light new insights into embryonic growth dynamics, with implications spanning reproductive medicine, stem cell research, and regenerative medicine. The review explores the key metabolic processes and molecular pathways active during preimplantation embryo development, including PI3K-Akt, mTOR, AMPK, Wnt/β-catenin, TGF-β, Notch and Jak-Stat signaling pathways. We focused on analyzing the differences occurring in vitro as opposed to in vivo development and we discussed significant physiological and clinical implications.

Beyond conventional treatment: ASGR1 Leading the new era of hypercholesterolemia management

Cardiovascular disease (CVD) remains a leading cause of mortality worldwide, with hypercholesterolemia being a major risk factor. Although various lipid-lowering therapies exist, many patients fail to achieve optimal cholesterol control, highlighting the need for novel therapeutic approaches. ASGR1 (asialoglycoprotein receptor 1), predominantly expressed on hepatocytes, has emerged as a key regulator of cholesterol metabolism and low-density lipoprotein (LDL) clearance. This receptor's ability to regulate lipid homeostasis positions it as a promising target for therapeutic intervention in hypercholesterolemia and related cardiovascular diseases. This review critically examines the biological functions and regulatory mechanisms of ASGR1 in cholesterol metabolism, with a focus on its potential as a therapeutic target for hypercholesterolemia and related cardiovascular diseases. By analyzing recent advances in ASGR1 research, this article explores its role in liver-specific pathways, the implications of ASGR1 variants in CVD risk, and the prospects for developing ASGR1-targeted therapies. This review aims to provide a foundation for future research and clinical applications in hypercholesterolemia management.

Advances in the Insulin-Heart Axis: Current Therapies and Future Directions

The insulin-heart axis plays a pivotal role in the pathophysiology of cardiovascular disease (CVD) in insulin-resistant states, including type 2 diabetes mellitus. Insulin resistance disrupts glucose and lipid metabolism, leading to systemic inflammation, oxidative stress, and atherogenesis, which contribute to heart failure (HF) and other CVDs. This review was conducted by systematically searching PubMed, Scopus, and Web of Science databases for peer-reviewed studies published in the past decade, focusing on therapeutic interventions targeting the insulin-heart axis. Studies were selected based on their relevance to insulin resistance, cardiovascular outcomes, and the efficacy of pharmacologic treatments. Key findings from the review highlight the efficacy of lifestyle modifications, such as dietary changes and physical activity, which remain the cornerstone of managing insulin resistance and improving cardiovascular outcomes. Moreover, pharmacologic interventions, such as metformin, sodium-glucose cotransporter 2 inhibitors, glucagon-like peptide-1 receptor agonists, and dipeptidyl peptidase-4 inhibitors, have shown efficacy in reducing cardiovascular risk by addressing metabolic dysfunction, reducing inflammation, and improving endothelial function. Furthermore, emerging treatments, such as angiotensin receptor-neprilysin inhibitors, and mechanical interventions like ventricular assist devices offer new avenues for managing HF in insulin-resistant patients. The potential of these therapies to improve left ventricular ejection fraction and reverse pathological cardiac remodeling highlights the importance of early intervention. However, challenges remain in optimizing treatment regimens and understanding the long-term cardiovascular effects of these agents. Future research should focus on personalized approaches that integrate lifestyle and pharmacologic therapies to effectively target the insulin-heart axis and mitigate the burden of cardiovascular complications in insulin-resistant populations.

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.

Metabolomic and Transcriptomic Analyses Reveal the Potential Mechanisms of Dynamic Ovarian Development in Goats during Sexual Maturation

The ovary is a crucial reproductive organ in mammals, and its development directly influences an individual's sexual maturity and reproductive capacity. To comprehensively describe ovarian sexual maturation in goats, we integrated phenotypic, hormonal, metabolomic, and transcriptomic data from four specific time points: after birth (D1), at 2 months old (M2), at 4 months old (M4), and at 6 month old (M6). The study showed that during the early stage (D1-M2), ovarian growth was the most rapid, with weight and morphology increasing by 284% and 65%, respectively, and hormone levels rose significantly, with estradiol increasing by 57%. Metabolomic analysis identified 1231 metabolites, primarily lipids, lipid molecules, and organic acids, which can support hormone balance and follicle development by providing energy and participating in signaling transduction. Transcriptomic analysis identified 543 stage-specific differentially expressed genes, mainly enriched in steroid biosynthesis, amino acid metabolism, and the PI3K/AKT pathway, which are key factors influencing ovarian cell proliferation, apoptosis, hormone secretion, and metabolism. The integrated analysis revealed the key processes in the ovarian steroid hormone biosynthesis pathway and gene/metabolite networks associated with ovarian phenotypes and hormone levels, ultimately highlighting scavenger receptor class B type 1 (SCARB1), Cytochrome P450 Family 1 Subfamily A Member 1 (CYP11A1), 3beta-hydroxysteroid dehydrogenase (3BHSD), progesterone, estradiol, and L-phenylalanine as key regulators of ovarian morphological and functional changes at different developmental stages. This study is the first to reveal the metabolic changes and molecular regulatory mechanisms during ovarian sexual maturation in goats, providing valuable insights for understanding reproductive system development and optimizing reproductive performance and breeding efficiency.

DBT is a metabolic switch for maintenance of proteostasis under proteasomal impairment

Proteotoxic stress impairs cellular homeostasis and underlies the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). The proteasomal and autophagic degradation of proteins are two major pathways for protein quality control in the cell. Here, we report a genome-wide CRISPR screen uncovering a major regulator of cytotoxicity resulting from the inhibition of the proteasome. Dihydrolipoamide branched chain transacylase E2 (DBT) was found to be a robust suppressor, the loss of which protects against proteasome inhibition-associated cell death through promoting clearance of ubiquitinated proteins. Loss of DBT altered the metabolic and energetic status of the cell and resulted in activation of autophagy in an AMP-activated protein kinase (AMPK)-dependent mechanism in the presence of proteasomal inhibition. Loss of DBT protected against proteotoxicity induced by ALS-linked mutant TDP-43 in Drosophila and mammalian neurons. DBT is upregulated in the tissues of ALS patients. These results demonstrate that DBT is a master switch in the metabolic control of protein quality control with implications in neurodegenerative diseases.

Differential symbiotic compatibilities between rhizobium strains and cultivated and wild soybeans revealed by anatomical and transcriptome analyses

Various species of rhizobium establish compatible symbiotic relationships with soybean (Glycine max) leading to the formation of nitrogen-fixing nodules in roots. The formation of functional nodules is mediated through complex developmental and transcriptional reprogramming that involves the activity of thousands of plant genes. However, host transcriptome that differentiate between functional or non-functional nodules remain largely unexplored. In this study, we investigated differential compatibilities between rhizobium strains (Bradyrhizobium diazoefficiens USDA110 Bradyrhizobium sp. strain LVM105) and cultivated and wild soybeans. The nodulation assays revealed that both USDA110 and LVM105 strains effectively nodulate G. soja but only USDA110 can form symbiotic relationships with Williams 82. LVM105 formed pseudonodules on Williams 82 that consist of a central nodule-like mass that are devoid of any rhizobia. RNA-seq data revealed that USDA110 and LVM105 induce distinct transcriptome programing in functional mature nodules formed on G. soja roots, where genes involved in nucleosome assembly, DNA replication, regulation of cell cycle, and defense responses play key roles. Transcriptome comparison also suggested that activation of genes associated with cell wall biogenesis and organization and defense responses together with downregulation of genes involved in the biosynthesis of isoprenoids and antioxidant stress are associated with the formation of non-functional nodules on Williams 82 roots. Moreover, our analysis implies that increased activity of genes involved in oxygen binding, amino acid transport, and nitrate transport differentiates between fully-developed nodules in cultivated versus wild soybeans.

Unraveling the Mystery of Energy-Sensing Enzymes and Signaling Pathways in Tumorigenesis and Their Potential as Therapeutic Targets for Cancer

Cancer research has advanced tremendously with the identification of causative genes, proteins, and signaling pathways. Numerous antitumor drugs have been designed and screened for cancer therapeutics; however, designing target-specific drugs for malignant cells with minimal side effects is challenging. Recently, energy-sensing- and homeostasis-associated molecules and signaling pathways playing a role in proliferation, apoptosis, autophagy, and angiogenesis have received increasing attention. Energy-metabolism-based studies have shown the contribution of energetics to cancer development, where tumor cells show increased glycolytic activity and decreased oxidative phosphorylation (the Warburg effect) in order to obtain the required additional energy for rapid division. The role of energy homeostasis in the survival of normal as well as malignant cells is critical; therefore, fuel intake and expenditure must be balanced within acceptable limits. Thus, energy-sensing enzymes detecting the disruption of glycolysis, AMP, ATP, or GTP levels are promising anticancer therapeutic targets. Here, we review the common energy mediators and energy sensors and their metabolic properties, mechanisms, and associated signaling pathways involved in carcinogenesis, and explore the possibility of identifying drugs for inhibiting the energy metabolism of tumor cells. Furthermore, to corroborate our hypothesis, we performed meta-analysis based on transcriptomic profiling to search for energy-associated biomarkers and canonical pathways.

Vitamin B12 Deficiency in Patients Taking Metformin: Pathogenesis and Recommendations

Metformin is a cornerstone therapy for type 2 diabetes mellitus due to its glucose-lowering efficacy and additional benefits such as reducing cardiovascular mortality. However, accumulating evidence suggests an association between long-term metformin use and vitamin B12 deficiency, which can lead to serious clinical consequences. This review aims to synthesize current knowledge on the pathogenesis, prevalence, clinical implications, and management of metformin-induced vitamin B12 deficiency. Given the significant clinical implications, it is crucial to monitor and manage vitamin B12 levels in patients using metformin. This review emphasizes the importance of early detection and supplementation to prevent adverse outcomes. By analyzing the current evidence, the review aims to inform healthcare professionals about best practices for managing vitamin B12 deficiency in patients on metformin, offering insights to guide future clinical practices and research directions.

LncRNAs are involved in regulating ageing and age-related disease through the adenosine monophosphate-activated protein kinase signalling pathway

A long noncoding RNA (lncRNA) is longer than 200 bp. It regulates various biological processes mainly by interacting with DNA, RNA, or protein in multiple kinds of biological processes. Adenosine monophosphate-activated protein kinase (AMPK) is activated during nutrient starvation, especially glucose starvation and oxygen deficiency (hypoxia), and exposure to toxins that inhibit mitochondrial respiratory chain complex function. AMPK is an energy switch in organisms that controls cell growth and multiple cellular processes, including lipid and glucose metabolism, thereby maintaining intracellular energy homeostasis by activating catabolism and inhibiting anabolism. The AMPK signalling pathway consists of AMPK and its upstream and downstream targets. AMPK upstream targets include proteins such as the transforming growth factor β-activated kinase 1 (TAK1), liver kinase B1 (LKB1), and calcium/calmodulin-dependent protein kinase β (CaMKKβ), and its downstream targets include proteins such as the mechanistic/mammalian target of rapamycin (mTOR) complex 1 (mTORC1), hepatocyte nuclear factor 4α (HNF4α), and silencing information regulatory 1 (SIRT1). In general, proteins function relatively independently and cooperate. In this article, a review of the currently known lncRNAs involved in the AMPK signalling pathway is presented and insights into the regulatory mechanisms involved in human ageing and age-related diseases are provided.

Molecular Mechanisms of Healthy Aging: The Role of Caloric Restriction, Intermittent Fasting, Mediterranean Diet, and Ketogenic Diet-A Scoping Review

As the population ages, promoting healthy aging through targeted interventions becomes increasingly crucial. Growing evidence suggests that dietary interventions can significantly impact this process by modulating fundamental molecular pathways. This review focuses on the potential of targeted dietary strategies in promoting healthy aging and the mechanisms by which specific nutrients and dietary patterns influence key pathways involved in cellular repair, inflammation, and metabolic regulation. Caloric restriction, intermittent fasting, the Mediterranean diet, as well as the ketogenic diet showed promising effects on promoting healthy aging, possibly by modulating mTORC1 AMPK, an insulin signaling pathway. By understanding the intricate interplay between diet and molecular pathways, we can develop personalized dietary strategies that not only prevent age-related diseases, but also promote overall health and well-being throughout the aging process.

A SNF1-related protein kinase regulatory subunit functions as a molecular tuner

Metabolic processes in prokaryotic and eukaryotic organisms are often modulated by kinases which are in turn, dependent on Ca2+ and the cyclic mononucleotides cAMP and cGMP. It has been established that some proteins have both kinase and cyclase activities and that active cyclases can be embedded within the kinase domains. Here, we identified phosphodiesterase (PDE) sites, enzymes that hydrolyse cAMP and cGMP, to AMP and GMP, respectively, in some of these proteins in addition to their kinase/cyclase twin-architecture. As an example, we tested the Arabidopsis thaliana KINγ, a subunit of the SnRK2 kinase, to demonstrate that all three enzymatic centres, adenylate cyclase (AC), guanylate cyclase (GC) and PDE, are catalytically active, capable of generating and hydrolysing cAMP and cGMP. These data imply that the signal output of the KINγ subunit modulates SnRK2, consequently affecting the downstream kinome. Finally, we propose a model where a single protein subunit, KINγ, is capable of regulating cyclic mononucleotide homeostasis, thereby tuning stimulus specific signal output.

The interaction between 20-hydroxyecdysone and AMPK through PI3K activation in Chinese mitten crab, Eriocheir sinensis

In crustaceans, the steroid hormone 20-hydroxyecdysone (20E) initiates molting, and the molting process is also regulated by energy metabolism. AMPK is an energy sensor and plays a critical role in systemic energy balance. Here, the regulatory mechanism in the interaction between 20E and AMPK was investigated in Chinese mitten crab, Eriocheir sinensis. The results showed that the 20E concentration and the mRNA expression levels of 20E receptors in hepatopancreas were down-regulated post AMPK activator (AICAR) treatment, and were up-regulated after AMPK inhibitor (Compound C) injection in crabs. Besides, the molt-inhibiting hormone (MIH) gene expression in eyestalk showed the opposite patterns in response to the AICAR and Compound C treatment, respectively. Further investigation found that there was a significant reduction in 20E concentration post PI3K inhibitor (LY294002) treatment, and the phosphorylation level of PI3K was increased in hepatopancreas after AMPK inhibitor injection. On the other hand, the positive regulation of PI3K-mediated activation of AMPK was also observed, the phosphorylation levels of AMPKα, AMPKβ and PI3K in hepatopancreas were significantly increased post 20E injection. In addition, the phosphorylation levels of AMPKα and AMPKβ induced by 20E were decreased after the injection of PI3K inhibitor. Taken together, these results suggest that the regulatory cross-talk between 20E and AMPK is likely to act through PI3K pathway in E. sinensis, which appeared to be helpful for a better understanding in molting regulation.

Advances in the interaction of glycolytic reprogramming with lactylation

Lactylation is a novel post-translational modification (PTM) involving proteins that is induced by lactate accumulation. Histone lysine lactylation alters chromatin spatial configuration, influencing gene transcription and regulating the expression of associated genes. This modification plays a crucial role as an epigenetic regulatory factor in the progression of various diseases. Glycolytic reprogramming is one of the most extensively studied forms of metabolic reprogramming, recognized as a key hallmark of cancer cells. It is characterized by an increase in glycolysis and the inhibition of the tricarboxylic acid (TCA) cycle, accompanied by significant lactate production and accumulation. The two processes are closely linked by lactate, which interacts in various physiological and pathological processes. On the one hand, lactylation levels generally correlate positively with the extent of glycolytic reprogramming, being directly influenced by the lactate concentration produced during glycolytic reprogramming. On the other hand, lactylation can also regulate glycolytic pathways by affecting the transcription and structural functions of essential glycolytic enzymes. This review comprehensively outlines the mechanisms of lactylation and glycolytic reprogramming and their interactions in tumor progression, immunity, and inflammation, with the aim of elucidating the relationship between glycolytic reprogramming and lactylation.

Formation of functional, extended bile canaliculi, and increased bile acid production in sandwich-cultured human cryopreserved hepatocytes using commercially available culture medium

Drug-induced cholestasis results in drug discontinuation and market withdrawal, and the prediction of cholestasis risk is critical in the early stages of drug development. Animal tests and membrane vesicle assay are currently being conducted to assess the risk of cholestasis in the preclinical stage. However, these methods have drawbacks, such as species differences with humans and difficulties in evaluating the effects of drug metabolism and other transporters, implying the need for a cholestasis risk assessment system using human hepatocytes. However, human hepatocytes hardly form functional, extended bile canaliculi, a requirement for cholestasis risk assessment. We previously established a culture protocol for functional, extended bile canaliculi formation in human iPSC-derived hepatocytes. In this study, we modified this culture protocol to support the formation of functional, extended bile canaliculi in human cryopreserved hepatocytes (cryoheps). The production of bile acids, which induces bile canaliculi extension, increased time-dependently during bile canaliculi formation using this protocol, suggesting that increased bile acid production may be involved in the extended bile canaliculi formation. We have also shown that our culture protocol can be applied to cryoheps from multiple donors and that bile canaliculi can be formed stably among different culture batches. Furthermore, this protocol enables long-term maintenance of bile canaliculi and scaling down to culture in 96-well plates. We expect our culture protocol to be a breakthrough for in vitro cholestasis risk assessment.

Inhibition of lactate dehydrogenase A by diclofenac sodium induces apoptosis in HeLa cells through activation of AMPK

Cancer cells exhibit a unique metabolic preference for the glycolytic pathway over oxidative phosphorylation for maintaining the tumor microenvironment. Lactate dehydrogenase A (LDHA) is a key enzyme that facilitates glycolysis by converting pyruvate to lactate and has been shown to be upregulated in multiple cancers due to the hypoxic tumor microenvironment. Diclofenac (DCF), a nonsteroidal anti-inflammatory drug, has been shown to exhibit anticancer effects by interfering with the glucose metabolism pathway. However, the specific targets of this drug remain unknown. Using in silico, biochemical, and biophysical studies, we show that DCF binds to LDHA adjacent to the substrate binding site and inhibits its activity in a dose-dependent and allosteric manner in HeLa cells. Thus, DCF inhibits the hypoxic microenvironment and induces apoptosis-mediated cell death. DCF failed to induce cytotoxicity in HeLa cells when LDHA was knocked down, confirming that DCF exerts its antimitotic effects via LDHA inhibition. DCF-induced LDHA inhibition alters pyruvate, lactate, NAD+, and ATP production in cells, and this could be a possible mechanism through which DCF inhibits glucose uptake in cancer cells. DCF-induced ATP deprivation leads to mitochondria-mediated oxidative stress, which results in DNA damage, lipid peroxidation, and apoptosis-mediated cell death. Reduction in intracellular ATP levels additionally activates the sensor kinase, adenosine monophosphate-activated protein kinase (AMPK), which further downregulates phosphorylated ribosomal S6 kinase (p-S6K), leading to apoptosis-mediated cell death. We find that in LDHA knocked down cells, intracellular ATP levels were depleted, resulting in the inhibition of p-S6K, suggesting the involvement of DCF-induced LDHA inhibition in the activation of the AMPK/S6K signaling pathway.

Mechano-metabolism of metastatic breast cancer cells in 2D and 3D microenvironments

Cells regulate their shape and metabolic activity in response to the mechano-chemical properties of their microenvironment. To elucidate the impact of matrix stiffness and ligand density on the bioenergetics of mesenchymal cells, we developed a nonequilibrium, active chemo-mechanical model that accounts for the mechanical energy of the cell and matrix, chemical energy from ATP hydrolysis, interfacial energy, and mechano-sensitive regulation of stress fiber assembly through signaling. By integrating the kinetics and energetics of these processes, we define the cell "metabolic potential" that, when minimized, provides testable predictions of cell contractility, shape, and ATP consumption. Specifically, we show that the morphology of MDA-MB-231 breast cancer cells in 3D collagen changes from spherical to elongated to spherical with increasing matrix stiffness, which is consistent with experimental observations. On 2D hydrogels, our model predicts a hemispherical-to-spindle-to-disc shape transition with increasing gel stiffness. In both cases, we show that these shape transitions emerge from competition between the energy of ATP hydrolysis associated with increased contractility that drives cell elongation and the interfacial energy that favors a rounded shape. Furthermore, our model can predict how increased energy demand in stiffer microenvironments is met by AMPK activation, which is confirmed experimentally in both 2D and 3D microenvironments and found to correlate with the upregulation of mitochondrial potential, glucose uptake, and ATP levels, as well as provide estimates of changes in intracellular adenosine nucleotide concentrations with changing environmental stiffness. Overall, we present a framework for relating adherent cell energy levels and contractility through biochemical regulation of underlying physical processes.

Statement of Significance

Increasing evidence indicates that cellular metabolism is regulated by mechanical cues from the extracellular environment. Forces transmitted from the microenvironment activate mechanotransduction pathways in the cell, which trigger a cascade of biochemical events that impact cytoskeletal tension, cellular morphology and energy budget available to the cell. Using a nonequilibrium free energy-based theory, we can predict the ATP consumption, contractility, and shape of mesenchymal cancer cells, as well as how cells regulate energy levels dependent on the mechanosensitive metabolic regulator AMPK. The insights from our model can be used to understand the mechanosensitive regulation of metabolism during metastasis and tumor progression, during which cells experience dynamic changes in their microenvironment and metabolic state.

Hyperglycemia-driven signaling bridges between diabetes and cancer

Growing epidemiological evidence indicates an association between obesity, type 2 diabetes, and certain cancers, suggesting the existence of common underlying mechanisms in these diseases. Frequent hyperglycemias in type 2 diabetes promote pro-inflammatory responses and stimulate intracellular metabolic flux which rewires signaling pathways and influences the onset and advancement of different types of cancers. Here, we review the provocative impact of hyperglycemia on a subset of interconnected signalling pathways that regulate (i) cell growth and survival, (ii) metabolism adjustments, (iii) protein function modulation in response to nutrient availability (iv) and cell fate and proliferation and which are driven respectively by PI3K (Phosphoinositide 3-kinase), AMPK (AMP-activated protein kinase), O-GlcNAc (O-linked N-acetylglucosamine) and Wnt/β-catenin. Specifically, we will elaborate on their involvement in glucose metabolism, inflammation, and cell proliferation, highlighting their interplay in the pathogenesis of diabetes and cancer. Furthermore, the influence of antineoplastic and antidiabetic drugs on the unbridled cellular pathways will be examined. This review aims to inspire the next molecular studies to understand how type 2 diabetes may lead to certain cancers. This will contribute to personalized medicine and direct better prevention strategies.

Hepatocyte programmed cell death: the trigger for inflammation and fibrosis in metabolic dysfunction-associated steatohepatitis

By replacing and removing defective or infected cells, programmed cell death (PCD) contributes to homeostasis maintenance and body development, which is ubiquitously present in mammals and can occur at any time. Besides apoptosis, more novel modalities of PCD have been described recently, such as necroptosis, pyroptosis, ferroptosis, and autophagy-dependent cell death. PCD not only regulates multiple physiological processes, but also participates in the pathogenesis of diverse disorders, including metabolic dysfunction-associated steatotic liver disease (MASLD). MASLD is mainly classified into metabolic dysfunction-associated steatotic liver (MASL) and metabolic dysfunction-associated steatohepatitis (MASH), and the latter putatively progresses to cirrhosis and hepatocellular carcinoma. Owing to increased incidence and obscure etiology of MASH, its management still remains a tremendous challenge. Recently, hepatocyte PCD has been attracted much attention as a potent driver of the pathological progression from MASL to MASH, and some pharmacological agents have been proved to exert their salutary effects on MASH partly via the regulation of the activity of hepatocyte PCD. The current review recapitulates the pathogenesis of different modalities of PCD, clarifies the mechanisms underlying how metabolic disorders in MASLD induce hepatocyte PCD and how hepatocyte PCD contributes to inflammatory and fibrotic progression of MASH, discusses several signaling pathways in hepatocytes governing the execution of PCD, and summarizes some potential pharmacological agents for MASH treatment which exert their therapeutic effects partly via the regulation of hepatocyte PCD. These findings indicate that hepatocyte PCD putatively represents a new therapeutic point of intervention for MASH.

Hepatic glucagon action: beyond glucose mobilization

Glucagon's ability to promote hepatic glucose production has been known for over a century, with initial observations touting this hormone as a diabetogenic agent. However, glucagon receptor agonism [when balanced with an incretin, including glucagon-like peptide 1 (GLP-1) to dampen glucose excursions] is now being developed as a promising therapeutic target in the treatment of metabolic diseases, like metabolic dysfunction-associated steatotic disease/metabolic dysfunction-associated steatohepatitis (MASLD/MASH), and may also have benefit for obesity and chronic kidney disease. Conventionally regarded as the opposing tag-team partner of the anabolic mediator insulin, glucagon is gradually emerging as more than just a "catabolic hormone." Glucagon action on glucose homeostasis within the liver has been well characterized. However, growing evidence, in part thanks to new and sensitive "omics" technologies, has implicated glucagon as more than just a "glucose liberator." Elucidation of glucagon's capacity to increase fatty acid oxidation while attenuating endogenous lipid synthesis speaks to the dichotomous nature of the hormone. Furthermore, glucagon action is not limited to just glucose homeostasis and lipid metabolism, as traditionally reported. Glucagon plays key regulatory roles in hepatic amino acid and ketone body metabolism, as well as mitochondrial turnover and function, indicating broader glucagon signaling consequences for metabolic homeostasis mediated by the liver. Here we examine the broadening role of glucagon signaling within the hepatocyte and question the current dogma, to appreciate glucagon as more than just that "catabolic hormone."

AMPED study: Protocol for a randomized controlled trial of different doses of aerobic exercise training

Recently renamed, metabolic dysfunction-associated steatotic liver disease remains a leading cause of chronic liver disease worldwide. Regular physical activity is recommended as a treatment for all with this condition because it is highly efficacious, especially when exercise training is undertaken with a specific goal in mind. Despite decades of research demonstrating exercise's efficacy, key questions remain about the mechanism of benefit and most efficacious dose, as well as the independent impact on liver histology. To answer these questions, we present the design of a 16-week randomized controlled clinical trial of 45 adults aged 18-69 years with metabolic dysfunction-associated steatohepatitis. The primary aim of this study is to better understand the dose required and mechanisms to explain how exercise impacts multiple clinical end points in metabolic dysfunction-associated steatohepatitis. The primary outcome is MRI-measured liver fat. Secondary outcomes include other biomarkers of liver fibroinflammation, liver histology, and mechanistic pathways, as well as cardiometabolic risk and quality of life. This is the first study to compare different doses of exercise training to determine if there is a differential impact on imaging and serum biomarkers as well as liver histology.

Ferroptosis: a novel mechanism of cell death in ophthalmic conditions

Ferroptosis, a new type of programmed cell death proposed in recent years, is characterized mainly by reactive oxygen species and iron-mediated lipid peroxidation and differs from programmed cell death, such as apoptosis, necrosis, and autophagy. Ferroptosis is associated with a variety of physiological and pathophysiological processes. Recent studies have shown that ferroptosis can aggravate or reduce the occurrence and development of diseases by targeting metabolic pathways and signaling pathways in tumors, ischemic organ damage, and other degenerative diseases related to lipid peroxidation. Increasing evidence suggests that ferroptosis is closely linked to the onset and progression of various ophthalmic conditions, including corneal injury, glaucoma, age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinoblastoma. Our review of the current research on ferroptosis in ophthalmic diseases reveals significant advancements in our understanding of the pathogenesis, aetiology, and treatment of these conditions.

AMPK Deficiency Increases DNA Methylation and Aggravates Colorectal Tumorigenesis in AOM/DSS Mice

The incidence of colorectal cancer (CRC) is closely linked to metabolic diseases. Accumulating evidence suggests the regulatory role of AMP-activated protein kinase (AMPK) in cancer metabolic reprogramming. In this study, wild-type and AMPK knockout mice were subjected to azoxymethane-induced and dextran sulfate sodium (AOM/DSS)-promoted colitis-associated CRC induction. A stable AMPK-deficient Caco-2 cell line was also established for the mechanistic studies. The data showed that AMPK deficiency accelerated CRC development, characterized by increased tumor number, tumor size, and hyperplasia in AOM/DSS-treated mice. The aggravated colorectal tumorigenesis resulting from AMPK ablation was associated with reduced α-ketoglutarate production and ten-eleven translocation hydroxylase 2 (TET2) transcription, correlated with the reduced mismatch repair protein mutL homolog 1 (MLH1) protein. Furthermore, in AMPK-deficient Caco-2 cells, the mRNA expression of mismatch repair and tumor suppressor genes, intracellular α-ketoglutarate, and the protein level of TET2 were also downregulated. AMPK deficiency also increased hypermethylation in the CpG islands of Mlh1 in both colonic tissues and Caco-2 cells. In conclusion, AMPK deficiency leads to reduced α-ketoglutarate concentration and elevates the suppressive epigenetic modifications of tumor suppressor genes in gut epithelial cells, thereby increasing the risk of colorectal tumorigenesis. Given the modifiable nature of AMPK activity, it holds promise as a prospective molecular target for the prevention and treatment of CRC.

Glycolytic enzymes in non-glycolytic web: functional analysis of the key players

To survive in the tumour microenvironment, cancer cells undergo rapid metabolic reprograming and adaptability. One of the key characteristics of cancer is increased glycolytic selectivity and decreased oxidative phosphorylation (OXPHOS). Apart from ATP synthesis, glycolysis is also responsible for NADH regeneration and macromolecular biosynthesis, such as amino acid biosynthesis and nucleotide biosynthesis. This allows cancer cells to survive and proliferate even in low-nutrient and oxygen conditions, making glycolytic enzymes a promising target for various anti-cancer agents. Oncogenic activation is also caused by the uncontrolled production and activity of glycolytic enzymes. Nevertheless, in addition to conventional glycolytic processes, some glycolytic enzymes are involved in non-canonical functions such as transcriptional regulation, autophagy, epigenetic changes, inflammation, various signaling cascades, redox regulation, oxidative stress, obesity and fatty acid metabolism, diabetes and neurodegenerative disorders, and hypoxia. The mechanisms underlying the non-canonical glycolytic enzyme activities are still not comprehensive. This review summarizes the current findings on the mechanisms fundamental to the non-glycolytic actions of glycolytic enzymes and their intermediates in maintaining the tumor microenvironment.

Floralozone regulates MiR-7a-5p expression through AMPKα2 activation to improve cognitive dysfunction in vascular dementia

BACKGROUND

The pathogenesis of vascular dementia (VD) is complex, and currently, no effective treatments have been recommended. Floralozone is a colorless liquid first discovered in Lagotis Gaertn. Recently, its medicinal value has been increasingly recognized. Our previous study has demonstrated that Floralozone can improve cognitive dysfunction in rats with VD by regulating the transient receptor potential melastatin 2 (TRPM2) and N-methyl-D-aspartate receptor (NMDAR) signaling pathways. However, the mechanism by which Floralozone regulates TRPM2 and NMDAR to improve VD remains unclear. AMP-activated protein kinase (AMPK) is an energy regulator in vivo; however, its role of AMPK activation in stroke remains controversial. MiR-7a-5p has been identified to be closely related to neuronal function.

PURPOSE

To explore whether Floralozone can regulate the miR-7a-5p level in vivo through AMPKα2 activation, affect the TRPM2 and NR2B expression levels, and improve VD symptoms.

METHODS

The VD model was established by a modified bilateral occlusion of the common carotid arteries (2-VO) of Sprague-Dawley (SD) rats and AMPKα2 KO transgenic (AMPKα2-/-) mice. Primary hippocampal neurons were modeled using oxygen and glucose deprivation (OGD). Morris water maze (MWM) test, hematoxylin-eosin staining (HE staining), and TUNEL staining were used to investigate the effects of Floralozone on behavior and hippocampal morphology in rats. Minichromosome maintenance complex component 2(MCM2) positive cells were used to investigate the effect of Floralozone on neurogenesis. Immunofluorescence staining, qRT-PCR, and western blot analysis were used to investigate the effect of Floralozone on the expression levels of AMPKα2, miR-7a-5p, TRPM2, and NR2B.

RESULTS

The SD rat experiment revealed that Floralozone improved spatial learning and memory, improved the morphology and structure of hippocampal neurons, reduced apoptosis of hippocampal neurons and promoted neurogenesis in VD rats. Floralozone could increase the miR-7a-5p expression level, activate AMPKα2 and NR2B expressions, and inhibit TRPM2 expression in hippocampal neurons of VD rats. The AMPKα2 KO transgenic (AMPKα2-/-) mice experiment demonstrated that Floralozone could regulate miR-7a-5p, TRPM2, and NR2B expression levels through AMPKα2 activation. The cell experiment revealed that the TRPM2 and NR2B expression levels were regulated by miR-7a-5p, whereas the AMPKα2 expression level was not.

CONCLUSION

Floralozone could regulate miR-7a-5p expression level by activating the protein expression of AMPKα2, control the protein expression of TRPM2 and NR2B, improve the morphology and structure of hippocampus neurons, reduce the apoptosis of hippocampus neurons, promote neurogenesis and improve the cognitive dysfunction.

T-cell metabolism in rheumatoid arthritis: focus on mitochondrial and lysosomal dysfunction

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by immune cell dysregulation, synovial hyperplasia, and progressive cartilage destruction. The loss of immunological self-tolerance against autoantigens is the crucial insult responsible for the pathogenesis of RA. These immune abnormalities are experienced many years before the onset of clinical arthritis.

OBJECTIVE

This review aims to discuss the metabolic status of T-cells in RA and focuses mainly on mitochondrial and lysosomal dysfunctions involved in altering the T-cell metabolism.

DISCUSSION

T-cells are identified as the primary initiators of immunological abnormalities in RA. These RA T-cells show a distinct metabolic pattern compared to the healthy individuals. Dampened glycolytic flux, poor ATP production, and shifting of glucose to the pentose phosphate pathway resulting in increased NADPH and decreased ROS levels are the common metabolic patterns observed in RA T-cells. Defective mtDNA due to lack of MRE11A gene, a key molecular actor for resection, and inefficient lysosomal function due to misplacement of AMPK on the lysosomal surface were found to be responsible for mitochondrial and lysosome dysfunction in RA. Targeting this mechanism in RA can alleviate aggressive T-cell phenotype and may control the severity of RA.

DBT is a metabolic switch for maintenance of proteostasis under proteasomal impairment

Proteotoxic stress impairs cellular homeostasis and underlies the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). The proteasomal and autophagic degradation of proteins are two major pathways for protein quality control in the cell. Here, we report a genome-wide CRISPR screen uncovering a major regulator of cytotoxicity resulting from the inhibition of the proteasome. Dihydrolipoamide branched chain transacylase E2 (DBT) was found to be a robust suppressor, the loss of which protects against proteasome inhibition-associated cell death through promoting clearance of ubiquitinated proteins. Loss of DBT altered the metabolic and energetic status of the cell and resulted in activation of autophagy in an AMP-activated protein kinase (AMPK)-dependent mechanism in the presence of proteasomal inhibition. Loss of DBT protected against proteotoxicity induced by ALS-linked mutant TDP-43 in Drosophila and mammalian neurons. DBT is upregulated in the tissues from ALS patients. These results demonstrate that DBT is a master switch in the metabolic control of protein quality control with implications in neurodegenerative diseases.

Exercise-Regulated Mitochondrial and Nuclear Signalling Networks in Skeletal Muscle

Exercise perturbs energy homeostasis in skeletal muscle and engages integrated cellular signalling networks to help meet the contraction-induced increases in skeletal muscle energy and oxygen demand. Investigating exercise-associated perturbations in skeletal muscle signalling networks has uncovered novel mechanisms by which exercise stimulates skeletal muscle mitochondrial biogenesis and promotes whole-body health and fitness. While acute exercise regulates a complex network of protein post-translational modifications (e.g. phosphorylation) in skeletal muscle, previous investigations of exercise signalling in human and rodent skeletal muscle have primarily focused on a select group of exercise-regulated protein kinases [i.e. 5' adenosine monophosphate-activated protein kinase (AMPK), protein kinase A (PKA), Ca2+/calmodulin-dependent protein kinase (CaMK) and mitogen-activated protein kinase (MAPK)] and only a small subset of their respective protein substrates. Recently, global mass spectrometry-based phosphoproteomic approaches have helped unravel the extensive complexity and interconnection of exercise signalling pathways and kinases beyond this select group and phosphorylation and/or translocation of exercise-regulated mitochondrial and nuclear protein substrates. This review provides an overview of recent advances in our understanding of the molecular events associated with acute endurance exercise-regulated signalling pathways and kinases in skeletal muscle with a focus on phosphorylation. We critically appraise recent evidence highlighting the involvement of mitochondrial and nuclear protein phosphorylation and/or translocation in skeletal muscle adaptive responses to an acute bout of endurance exercise that ultimately stimulate mitochondrial biogenesis and contribute to exercise's wider health and fitness benefits.

Lauric acid attenuates hepato-metabolic complications and molecular alterations in high-fat diet-induced nonalcoholic fatty liver disease in rats

Nonalcoholic fatty liver disease (NAFLD) has emerged as a major chronic liver illness characterized by increase of lipid content in the liver. This study investigated the role of lauric acid to treat NAFLD in male adult Sprague Dawley rats. In this study, to induce NAFLD in the rats, a high-fat diet (HFD) was administered for eight consecutive weeks. Lauric acid groups received lauric acid (250 and 500 mg/kg; orally), concurrently with HFD for eight consecutive weeks. Lauric acid could ameliorate the serum levels of TG, TC, ALT, AST, blood glucose, and insulin. Moreover, lauric acid significantly elevated the levels of SOD, GSH, catalase, and IL-10. Additionally, it lowered the hepatic levels of MDA, ROS, MPO, 4-HNE, interleukin (IL)-1β, and tumor necrosis factor (TNF-α). Furthermore, lauric acid significantly up-regulated the hepatic expression of IRS1, AMPK, PI3K, and SIRT1 genes. In parallel, lauric acid could improve the histopathological picture of the liver and reduce the liver apoptosis via decreasing the expression of annexin V (Anx V). Finally, our data proposed that lauric acid could be an effective candidate for the NAFLD treatment.

Interleukin-27 as a novel player in alleviating hepatic steatosis: Mechanistic insights from an in vitro analysis

Interleukin-27 (IL-27) is a recently discovered cytokine that has been implicated in inflammatory and metabolic conditions, such as atherosclerosis and insulin resistance. However, the mechanisms by which IL-27 attenuates hepatic lipid accumulation in hyperlipidemic conditions and counteracts endoplasmic reticulum (ER) stress, a known risk factor for impaired hepatic lipid metabolism, have not been elucidated. This in vitro study was designed to examine the effect of IL-27 on hepatic lipid metabolism. The study included the evaluation of lipogenesis-associated proteins and ER stress markers by Western blotting, the determination of hepatic lipid accumulation by Oil Red O staining, and the examination of autophagosome formation by MDC staining. The results showed that IL-27 treatment reduced lipogenic lipid deposition and the expression of ER stress markers in cultured hepatocytes exposed to palmitate. Moreover, treatment with IL-27 suppressed CD36 expression and enhanced fatty acid oxidation in palmitate-treated hepatocytes. The effects of IL-27 on hyperlipidemic hepatocytes were attenuated when adenosine monophosphate-activated protein kinase (AMPK) or 3-methyladenine (3 MA) were inhibited by small interfering RNA (siRNA). These results suggest that IL-27 attenuates hepatic ER stress and fatty acid uptake and stimulates fatty acid oxidation via AMPK/autophagy signaling, thereby alleviating hepatic steatosis. In conclusion, this study identified IL-27 as a promising therapeutic target for nonalcoholic fatty liver disease (NAFLD).

Identification of the principal neuropeptide MIP and its action pathway in larval settlement of the echiuran worm Urechis unicinctus

BACKGROUND

Larval settlement and metamorphosis represent critical events in the life history of marine benthic animals. Myoinhibitory peptide (MIP) plays a pivotal role in larval settlement of marine invertebrates. However, the molecular mechanisms of MIP involved in this process are not well understood.

RESULTS

In this study, we evaluated the effects of thirteen MIP mature peptides on triggering the larval settlement of Urechis unicinctus (Xenopneusta, Urechidae), and determined that MIP2 was the principal neuropeptide. Transcriptomic analysis was employed to identify differentially expressed genes (DEGs) between the MIP2-treated larvae and normal early-segmentation larvae. Both cAMP and calcium signaling pathways were enriched in the DEGs of the MIP2-treated larvae, and two neuropeptide receptor genes (Spr, Fmrfar) were up-regulated in the MIP2-treated larvae. The activation of the SPR-cAMP pathway by MIP2 was experimentally validated in HEK293T cells. Furthermore, fourteen cilia-related genes, including Tctex1d2, Cfap45, Ift43, Ift74, Ift22, Cav1 and Mns1, etc. exhibited down-regulated expression in the MIP2-treated larvae. Whole-mount in situ hybridization identified two selected ciliary genes, Tctex1d2 and Cfap45, were specially expressed in circumoral ciliary cells of the early-segmentation larvae. Knocking down Tctex1d2 mRNA levels by in vivo RNA interference significantly increased the larval settlement rate.

CONCLUSION

Our findings suggest that MIP2 inhibits the function of the cilia-related genes, such as Tctex1d2, through the SPR-cAMP-PKA pathway, thereby inducing larval settlement in U. unicinctus. The study contributes important data to the understanding of neuropeptide regulation in larval settlement.

Alcohol and its metabolites dysregulate cellular bioenergetics and induce oxidative and endoplasmic reticulum stress in primary human bronchial epithelial cells

BACKGROUND

Chronic alcohol consumption/misuse is a significant risk factor for pneumonia and lung infection leading to the development of chronic pulmonary disorders such as chronic obstructive pulmonary disease (COPD) and lung fibrosis. In this study, we sought to delineate the mechanism of alcohol-associated lung disease. We did so by measuring in vitro mitochondrial, endoplasmic reticulum (ER) oxidative stress in human bronchial epithelial cells (hBECs) treated with ethanol and its oxidative (acetaldehyde) and nonoxidative (fatty acid ethyl esters or FAEEs) metabolites.

METHODS

Primary hBECs from a normal subject were treated with relevant concentrations of ethanol and its metabolites and incubated at 37°C for 24 h. Viability and cytotoxicity were determined using cell viability and lactate dehydrogenase (LDH) assay kits, respectively. Oxidized glutathione (GSSG) and reduced glutathione (GSH) were measured by colorimetric reaction, and 4-hydroxynenonal (4HNE) by immunohistochemistry. Endoplasmic reticulum stress and dysregulated cellular bioenergetics were determined by western blot analysis. Mitochondrial stress and real-time ATP production rates were determined using a Seahorse Extracellular Flux analyzer. Amelioration of ethanol-induced oxidative/ER stress and mitochondrial energetics was determined using an AMPKα agonist.

RESULTS

Human bronchial epithelial cells treated with ethanol, acetaldehyde, and FAEEs showed a concentration-dependent increase in the secretion of LDH, oxidative/ER stress, deactivation of AMPKα phosphorylation and mitochondrial stress (decreased spare respiratory capacity) with concomitant decreases in mitochondrial and glycolytic ATP production rates. FAEEs caused greater cytotoxicity, ER stress, and dysregulated cellular bioenergetics than those ethanol and its oxidative metabolite. AMPKα agonist-pretreated cells significantly ameliorated ethanol-induced oxidative/ER stress, deactivation of AMPKα, and dysregulated cellular bioenergetics.

CONCLUSIONS

Findings of this study suggest that ethanol and its metabolites contribute to cytotoxicity, oxidative/ER stress, and dysregulation of cellular bioenergetics in hBECs. The attenuation of ethanol-induced ER/oxidative stress and mitochondrial respiration by an AMPKα agonist may reflect a potential for it to be developed as a therapeutic agent for chronic alcohol-associated lung disease.

Novel therapeutics to treat chronic pancreatitis: targeting pancreatic stellate cells and macrophages

INTRODUCTION

Chronic pancreatitis (CP) is a persistent, recurrent, and progressive disorder that is characterized by chronic inflammation and irreversible fibrosis of the pancreas. It is associated with severe morbidity, resulting in intense abdominal pain, diabetes, exocrine and endocrine dysfunction, and an increased risk of pancreatic cancer. The etiological factors are diverse and the major risk factors include smoking, chronic alcoholism, as well as other environmental and genetic factors. The treatment and management of CP is challenging, and no definitive curative therapy is currently available.

AREAS COVERED

This review paper aims to provide an overview of the different cell types in the pancreas that is known to mediate disease progression and outline potential novel therapeutic approaches and drug targets that may be effective in treating and managing CP. The information presented in this review was obtained by conducting a NCBI PubMed database search, using relevant keywords.

EXPERT OPINION

In recent years, there has been an increased interest in the development of novel therapeutics for CP. A collaborative multi-disciplinary approach coupled with a consistent funding for research can expedite progress of translating the findings from bench to bedside.

Senolytic therapeutics: An emerging treatment modality for osteoarthritis

Osteoarthritis (OA), a chronic joint disease affecting millions of people aged over 65 years, is the main musculoskeletal cause of diminished joint mobility in the elderly. It is characterized by lingering pain and increasing deterioration of articular cartilage. Aging and accumulation of senescent cells (SCs) in the joints are frequently associated with OA. Apoptosis resistance; irreversible cell cycle arrest; increased p16INK4a expression, secretion of senescence-associated secretory phenotype factors, senescence-associated β-galactosidase levels, secretion of extracellular vesicles, and levels of reactive oxygen and reactive nitrogen species; and mitochondrial dysregulation are some common changes in cellular senescence in joint tissues. Development of OA correlates with an increase in the density of SCs in joint tissues. Senescence-associated secretory phenotype has been linked to OA and cartilage breakdown. Senolytics and therapeutic pharmaceuticals are being focused upon for OA management. SCs can be selectively eliminated or killed by senolytics to halt the pathogenesis and progression of OA. Comprehensive understanding of how aging affects joint dysfunction will benefit OA patients. Here, we discuss age-related mechanisms associated with OA pathogenesis and senolytics as an emerging modality in the management of age-related SCs and pathogenesis of OA in preclinical and clinical studies.

Interleukin-38 alleviates hepatic steatosis through AMPK/autophagy-mediated suppression of endoplasmic reticulum stress in obesity models

Interleukin-38 (IL-38), recently recognized as a cytokine with anti-inflammatory properties that mitigate type 2 diabetes, has been associated with indicators of insulin resistance and nonalcoholic fatty liver disease (NAFLD). This study investigated the impact of IL-38 on hepatic lipid metabolism and endoplasmic reticulum (ER) stress. We assessed protein expression levels using Western blot analysis, while monodansylcadaverine staining was employed to detect autophagosomes in hepatocytes. Oil red O staining was utilized to examine lipid deposition. The study revealed elevated serum IL-38 levels in high-fat diet (HFD)-fed mice and IL-38 secretion from mouse keratinocytes. IL-38 treatment attenuated lipogenic lipid accumulation and ER stress markers in hepatocytes exposed to palmitate. Furthermore, IL-38 treatment increased AMP-activated protein kinase (AMPK) phosphorylation and autophagy. The effects of IL-38 on lipogenic lipid deposition and ER stress were nullified in cultured hepatocytes by suppressing AMPK through small interfering (si) RNA or 3-methyladenine (3MA). In animal studies, IL-38 administration mitigated hepatic steatosis by suppressing the expression of lipogenic proteins and ER stress markers while reversing AMPK phosphorylation and autophagy markers in the livers of HFD-fed mice. Additionally, AMPK siRNA, but not 3MA, mitigated IL-38-enhanced fatty acid oxidation in hepatocytes. In summary, IL-38 alleviates hepatic steatosis through AMPK/autophagy signaling-dependent attenuation of ER stress and enhancement of fatty acid oxidation via the AMPK pathway, suggesting a therapeutic strategy for treating NAFLD.

Gene Expression Profiling Reveals Fundamental Sex-Specific Differences in SIRT3-Mediated Redox and Metabolic Signaling in Mouse Embryonic Fibroblasts

Sirt-3 is an important regulator of mitochondrial function and cellular energy homeostasis, whose function is associated with aging and various pathologies such as Alzheimer's disease, Parkinson's disease, cardiovascular diseases, and cancers. Many of these conditions show differences in incidence, onset, and progression between the sexes. In search of hormone-independent, sex-specific roles of Sirt-3, we performed mRNA sequencing in male and female Sirt-3 WT and KO mouse embryonic fibroblasts (MEFs). The aim of this study was to investigate the sex-specific cellular responses to the loss of Sirt-3. By comparing WT and KO MEF of both sexes, the differences in global gene expression patterns as well as in metabolic and stress responses associated with the loss of Sirt-3 have been elucidated. Significant differences in the activities of basal metabolic pathways were found both between genotypes and between sexes. In-depth pathway analysis of metabolic pathways revealed several important sex-specific phenomena. Male cells mount an adaptive Hif-1a response, shifting their metabolism toward glycolysis and energy production from fatty acids. Furthermore, the loss of Sirt-3 in male MEFs leads to mitochondrial and endoplasmic reticulum stress. Since Sirt-3 knock-out is permanent, male cells are forced to function in a state of persistent oxidative and metabolic stress. Female MEFs are able to at least partially compensate for the loss of Sirt-3 by a higher expression of antioxidant enzymes. The activation of neither Hif-1a, mitochondrial stress response, nor oxidative stress response was observed in female cells lacking Sirt-3. These findings emphasize the sex-specific role of Sirt-3, which should be considered in future research.

Sugar signals pedal the cell cycle!

Cell cycle involves the sequential and reiterative progression of important events leading to cell division. Progression through a specific phase of the cell cycle is under the control of various factors. Since the cell cycle in multicellular eukaryotes responds to multiple extracellular mitogenic cues, its study in higher forms of life becomes all the more important. One such factor regulating cell cycle progression in plants is sugar signalling. Because the growth of organs depends on both cell growth and proliferation, sugars sensing and signalling are key control points linking sugar perception to regulation of downstream factors which facilitate these key developmental transitions. However, the basis of cell cycle control via sugars is intricate and demands exploration. This review deals with the information on sugar and TOR-SnRK1 signalling and how they manoeuvre various events of the cell cycle to ensure proper growth and development.

AMPK stimulation inhibits YAP/TAZ signaling to ameliorate hepatic fibrosis

Hepatic fibrosis is driven by the activation of hepatic stellate cells (HSCs). The Hippo pathway and its effectors, YAP and TAZ, are key regulators of HSC activation and fibrosis. However, there is a lack of mechanistic understanding of YAP/TAZ regulation in HSCs. Here we show that AMPK activation leads to YAP/TAZ inhibition and HSC inactivation in vitro, while the expression of a kinase-inactive mutant reversed these effects compared to wild type AMPKɑ1. Notably, the depletion of LATS1/2, an upstream kinase of YAP/TAZ signaling, rescues YAP/TAZ activation, suggesting that AMPK may be mediating YAP/TAZ inhibition via LATS1/2. In the carbon tetrachloride mouse model of fibrosis, pharmacologic activation of AMPK in HSCs inhibits YAP/TAZ signaling and reduces fibrosis. The findings implicate AMPK as a critical regulator of YAP/TAZ signaling and HSC inactivation and highlight AMPK activation as a therapeutic target for the treatment of hepatic fibrosis.

Energy depletion by cell proliferation sensitizes the kidney epithelial cells to injury

Acute kidney injury activates both proliferative and antiproliferative pathways, the consequences of which are not fully elucidated. If an initial proliferation of the renal epithelium is necessary for the successful repair, the persistence of proliferation markers is associated with the occurrence of chronic kidney disease. We hypothesized that proliferation in stress conditions impacts cell viability and renal outcomes. We found that proliferation is associated with cell death after various stresses in kidney cells. In vitro, the ATP/ADP ratio oscillates reproducibly throughout the cell cycle, and cell proliferation is associated with a decreased intracellular ATP/ADP ratio. In vivo, transcriptomic data from transplanted kidneys revealed that proliferation was strongly associated with a decrease in the expression of the mitochondria-encoded genes of the oxidative phosphorylation pathway, but not of the nucleus-encoded ones. These observations suggest that mitochondrial function is a limiting factor for energy production in proliferative kidney cells after injury. The association of increased proliferation and decreased mitochondrial function was indeed associated with poor renal outcomes. In summary, proliferation is an energy-demanding process impairing the cellular ability to cope with an injury, highlighting proliferative repair and metabolic recovery as indispensable and interdependent features for successful kidney repair.NEW & NOTEWORTHY ATP depletion is a hallmark of acute kidney injury. Proliferation is instrumental to kidney repair. We show that ATP levels vary during the cell cycle and that proliferation sensitizes renal epithelial cells to superimposed injuries in vitro. More proliferation and less energy production by the mitochondria are associated with adverse outcomes in injured kidney allografts. This suggests that controlling the timing of kidney repair might be beneficial to mitigate the extent of acute kidney injury.

Targeting the Warburg effect: A revisited perspective from molecular mechanisms to traditional and innovative therapeutic strategies in cancer

Cancer reprogramming is an important facilitator of cancer development and survival, with tumor cells exhibiting a preference for aerobic glycolysis beyond oxidative phosphorylation, even under sufficient oxygen supply condition. This metabolic alteration, known as the Warburg effect, serves as a significant indicator of malignant tumor transformation. The Warburg effect primarily impacts cancer occurrence by influencing the aerobic glycolysis pathway in cancer cells. Key enzymes involved in this process include glucose transporters (GLUTs), HKs, PFKs, LDHs, and PKM2. Moreover, the expression of transcriptional regulatory factors and proteins, such as FOXM1, p53, NF-κB, HIF1α, and c-Myc, can also influence cancer progression. Furthermore, lncRNAs, miRNAs, and circular RNAs play a vital role in directly regulating the Warburg effect. Additionally, gene mutations, tumor microenvironment remodeling, and immune system interactions are closely associated with the Warburg effect. Notably, the development of drugs targeting the Warburg effect has exhibited promising potential in tumor treatment. This comprehensive review presents novel directions and approaches for the early diagnosis and treatment of cancer patients by conducting in-depth research and summarizing the bright prospects of targeting the Warburg effect in cancer.

Anti-inflammatory effect and mechanism of active parts of Artemisia mongolica in LPS-induced Raw264.7 cells based on network pharmacology analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia mongolica is well known for its use in folk medicine, it is commonly used to alleviate a variety of diseases associated with inflammation, such as laryngitis, tonsillitis, headaches and hepatitis in northwest China. However, its anti-inflammatory mechanism is still unknown.

AIM OF THE STUDY

The most potential anti-inflammatory part (AMPA) was identified by screening individual parts of A. Mongolica. After the network pharmacological analysis, the anti-inflammation effects and molecular mechanisms of AMPA were evaluated in RAW264.7 cells induced by LPS.

MATERIALS AND METHODS

AMPA was chosen as the most anti-inflammatory of the A. Mongolica, as measured by the effect of each part of the A. Mongolica on NO and COX-2. The chemical composition of AMPA was identified using HPLC-Q-TOF-MS/MS, and targets of bioactive chemicals and targets related to inflammation were found using open-source databases. The "Compound-targets" network and PPI network were established by combining compounds and overlapped targets, and targets in the PPI networks were analyzed by GO and KEGG enrichment. The RAW26.7 cells induced by LPS were used as a model of inflammation examination. MTT assay was performed to assess the cytotoxicity of AMPA on LPS-induced RAW264.7 cells. The level of NO was measured by the Griess method while the inflammatory factors were detected by ELISA. The protein expression levels of iNOS, COX-2, MAPK, NF-κB signaling pathway and AMPK/Nrf2-related proteins were determined by Western blot. The results of nuclear translocation of p65 and Nrf2 were analyzed by immunofluorescence assay.

RESULTS

A total of 18 compounds with potential bioactivity were identified, and after intersecting 640 compound-predicted targets and 1608 inflammation targets, the compounds and intersected targets were utilized to structure "compound-target" and PPI networks. Among AMPA, AM6, AM7, AM11, AM8 and AM1 compounds were essential in the "compound-targets" network, meanwhile, TNF, RELA, MAPK1, NOS2, PRKAG, and PTGS2 targets play important roles in the PPI network. The top 10 terms and pathways were obtained based on GO and KEGG. The cell experiments show that 50 μg/mL was the maximum concentration of AMPA without cytotoxicity in the LPS-induced RAW264.7 cell model. When compared with the LPS group, AMPA treatment not only effectively suppressed the generation of NO, TNF-α, IL-6, PGE2, IL-1β and MCP-1 in LPS-induced RAW264.7 cells, but also down-regulated the expression of COX-2, iNOS and the protein levels p-ERK, p-p38, p-IκB-α and p-p65, inhibited the nuclear translocation of p65. Furthermore, the expression levels of p-LKB1, p-AMPK, Nrf2 and HO-1 proteins were up-regulated and Nrf2 nuclear translocation was promoted.

CONCLUSION

AMPA should be considered an anti-inflammatory agent for the results of network pharmacology and in vitro, which could inhibit the MAPK pathway and NF-κB pathway and activate the AMPK/Nrf2 pathway in LPS-stimulated RAW264.7 cells.

PRKAA2, MTOR, and TFEB in the regulation of lysosomal damage response and autophagy

Lysosomes function as critical signaling hubs that govern essential enzyme complexes. LGALS proteins (LGALS3, LGALS8, and LGALS9) are integral to the endomembrane damage response. If ESCRT fails to rectify damage, LGALS-mediated ubiquitination occurs, recruiting autophagy receptors (CALCOCO2, TRIM16, and SQSTM1) and VCP/p97 complex containing UBXN6, PLAA, and YOD1, initiating selective autophagy. Lysosome replenishment through biogenesis is regulated by TFEB. LGALS3 interacts with TFRC and TRIM16, aiding ESCRT-mediated repair and autophagy-mediated removal of damaged lysosomes. LGALS8 inhibits MTOR and activates TFEB for ATG and lysosomal gene transcription. LGALS9 inhibits USP9X, activates PRKAA2, MAP3K7, ubiquitination, and autophagy. Conjugation of ATG8 to single membranes (CASM) initiates damage repair mediated by ATP6V1A, ATG16L1, ATG12, ATG5, ATG3, and TECPR1. ATG8ylation or CASM activates the MERIT system (ESCRT-mediated repair, autophagy-mediated clearance, MCOLN1 activation, Ca2+ release, RRAG-GTPase regulation, MTOR modulation, TFEB activation, and activation of GTPase IRGM). Annexins ANAX1 and ANAX2 aid damage repair. Stress granules stabilize damaged membranes, recruiting FLCN-FNIP1/2, G3BP1, and NUFIP1 to inhibit MTOR and activate TFEB. Lysosomes coordinate the synergistic response to endomembrane damage and are vital for innate and adaptive immunity. Future research should unveil the collaborative actions of ATG proteins, LGALSs, TRIMs, autophagy receptors, and lysosomal proteins in lysosomal damage response.