Role of AMPK in autophagy

Nobiletin ameliorates monosodium urate-induced gouty arthritis in mice by enhancing AMPK/mTOR-mediated autophagy to inhibit NF-κB/NLRP3 inflammasome activation

BACKGROUND

Gouty arthritis (GA) is a common rheumatic disease caused by the release of monosodium urate crystal (MSU) deposits into joint space. Nobiletin is a polymethoxylated flavonoid isolated from citrus fruits and has many beneficial activities. This study aimed to elucidate the therapeutic efficacy of nobiletin in GA and to reveal its potential mechanisms.

METHODS

Phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 macrophages were primed with lipopolysaccharide (LPS) and then stimulated with MSU crystals in the presence or absence of nobiletin. Cell viability as well as the levels of proinflammatory cytokines, pathway-related proteins, NLRP3 inflammasomes, and autophagy-related proteins were evaluated. MSU was used to induce GA in mice. Hematoxylin-eosin staining was conducted to assess histological morphology changes. Immunofluorescence staining was performed to measure LC3 expression in THP-1 cells and ankle joint tissues.

RESULTS

For in vitro analysis, nobiletin reduced LPS and MSU-induced cell viability inhibition. Additionally, nobiletin inhibited inflammation and NF-κB/NLRP3 pathway in THP-1 cells. Moreover, nobiletin inhibited the activation of NLRP3 inflammasome by promoting AMPK/mTOR-mediated autophagy. For in vivo analysis, nobiletin attenuated MSU-induced GA in mice. Additionally, nobiletin suppressed inflammation and NF-κB/NLRP3 pathway and promoted tissue autophagy in GA mice.

CONCLUSION

Nobiletin prevents MSU-induced GA in mice by inhibiting NF-κB/NLRP3 inflammasome activation through AMPK/mTOR-mediated autophagy.

Olmesartan attenuates doxorubicin-elicited testicular toxicity: The interaction between sirtuin-1, HMGB1/NLRP3 inflammasome/gasdermin D signaling, and AMPK/mTOR-driven autophagy

BACKGROUND

In the recent years, there has been an increased incidence of testicular toxicity associated with doxorubicin (DOX) use in cancer therapy. The mechanisms of this adverse effect may include induction of oxidative stress with augmentation of the inflammatory and the apoptotic signals in the testicular tissues. The ongoing research is directed towards the exploration of new agents that are capable of overcoming this health problem. This study was a trial to evaluate the efficacy of Olmesartan as a protective agent against DOX-induced testicular dysfunction in male rats.

MATERIALS AND METHODS

Forty adult male Sprague-Dawley rats were divided into control group, DOX-injected group, and three DOX-injected groups treated with olmesartan at 3 dose levels (1, 5, and 10 mg/kg/day). The effect of the different treatments was assessed at the biochemical and the morphological levels.

KEY FINDINGS

Olmesartan administered to DOX-treated rats induced dose-dependent restoration of the testicular weight and functions, normalization of the hormonal profile, augmentation of the antioxidant defenses, and potentiation of AMPK/mTOR-driven autophagy in comparison to rats treated with DOX alone. These effects were accompanied with a dose-dependent significant mitigation of the cellular events related to pyroptosis and inflammation and a significant amelioration of the testicular morphological changes induced by DOX.

SIGNIFICANCE

Olmesartan may represent a promising therapy for DOX-elicited testicular dysfunction, possibly via dose-dependent antioxidant, anti-pyroptotic, anti-inflammatory, and autophagy enhancing effects.

Dysregulated inflammation, oxidative stress, and protein quality control in diabetic HFpEF: unraveling mechanisms and therapeutic targets

BACKGROUND

Type 2 diabetes mellitus (T2DM) represents a significant risk factor for cardiovascular disease, particularly heart failure with preserved ejection fraction (HFpEF). HFpEF predominantly affects elderly individuals and women, and is characterized by dysfunctions associated with metabolic, inflammatory, and oxidative stress pathways. Despite HFpEF being the most prevalent heart failure phenotype in patients with T2DM, its underlying pathophysiological mechanisms remain inadequately elucidated.

OBJECTIVE

This study aims to investigate the effects of diabetes mellitus on myocardial inflammation, oxidative stress, and protein quality control (PQC) mechanisms in HFpEF, with particular emphasis on insulin signaling, autophagy, and chaperone-mediated stress responses.

METHODS

We conducted an analysis of left ventricular myocardial tissue from HFpEF patients, both with and without diabetes, employing a range of molecular, biochemical, and functional assays. The passive stiffness of cardiomyocytes (Fpassive) was assessed in demembranated cardiomyocytes before and after implementing treatments aimed at reducing inflammation (IL-6 inhibition), oxidative stress (Mito-TEMPO), and enhancing PQC (HSP27, HSP70). Inflammatory markers (NF-κB, IL-6, TNF-α, ICAM-1, VCAM-1, NLRP3), oxidative stress markers (ROS, GSH/GSSG ratio, lipid peroxidation), and components of signaling pathways (PI3K/AKT/mTOR, AMPK, MAPK, and PKG) were evaluated using western blotting, immunofluorescence, and ELISA techniques.

RESULTS

Hearts from diabetic HFpEF patients exhibited significantly heightened inflammation, characterized by the upregulation of NF-κB, IL-6, and the NLRP3 inflammasome. This increase in inflammation was accompanied by elevated oxidative stress, diminished nitric oxide (NO) bioavailability, and impaired activation of the NO-sGC-cGMP-PKG signaling pathway. Notably, dysregulation of insulin signaling was observed, as indicated by decreased AKT phosphorylation and impaired autophagy regulation mediated by AMPK and mTOR. Additionally, PQC dysfunction was evidenced by reduced expression levels of HSP27 and HSP70, which correlated with increased cardiomyocyte passive stiffness. Targeted therapeutic interventions effectively reduced Fpassive, with IL-6 inhibition, Mito-TEMPO, and HSP administration leading to improvements in cardiomyocyte mechanical properties.

CONCLUSION

The findings of this study elucidate a mechanistic relationship among diabetes, inflammation, oxidative stress, and PQC impairment in the context of HFpEF. Therapeutic strategies that target these dysregulated pathways, including IL-6 inhibition, mitochondrial antioxidants, and chaperone-mediated protection, may enhance myocardial function in HFpEF patients with T2DM. Addressing these molecular dysfunctions could facilitate the development of novel interventions specifically tailored to the diabetic HFpEF population.

AMPK-specific autophagy activator based on 1,3-diaza-2-oxophenoxazine

The dynamic equilibrium between synthesis and degradation of biomolecules is maintained by cells, however, with aging, this balance is disrupted, resulting in the onset of diseases, including diabetes and neurodegenerative diseases. A decrease in autophagy, a key cellular process that is involved in lysosome-mediated degradation of damaged or dysfunctional cellular components, may contribute to this imbalance. Autophagy is strictly regulated within the cell through multiple signaling pathways, e.g., through the AMPK-dependent pathway, which functions as a key sensor of cellular energy limitation. In this study, we assessed the autophagy/mitophagy activation ability of a small set of 1,3-diaza-2-oxophenoxazine derivatives and analogs using a fluorescent reporter assay and immunoblot analysis. The two lead compounds, AR493 and AR900, which exhibited the highest autophagy induction levels, were demonstrated to activate the AMPK-dependent pathway. The introduction of a 2'-hydroxyl group into AR493 had almost no influence on its activity, while subsequent attachment of a metabolizable masked phosphate group resulted in a notable increase in activity, although accompanied by substantial toxicity. When analyzing the specificity of the lead compounds to AMPK and its main upstream regulator SIRT1 on the corresponding knockout cell lines, AR493 demonstrated the greatest specificity of action to AMPK. Molecular docking revealed that AR493 binds to Site 2 of the AMPK γ-subunit, which may promote AMPK activation by two possible mechanisms: by preventing ATP binding to Site 3, thus favoring AMP binding; and by directly engaging the αRIM2 motif to stabilize its interaction with the γ-subunit.

Dysregulation of autophagy during photoaging reduce oxidative stress and inflammatory damage caused by UV

Photoaging, the premature aging of skin due to chronic ultraviolet (UV) exposure, is a growing concern in dermatology and cosmetic science. While UV radiation is known to induce DNA damage, oxidative stress, and inflammation in skin cells, recent research unveils a promising countermeasure: autophagy. This review explores the intricate relationship between autophagy and photoaging, highlighting how this cellular recycling process can mitigate UV-induced damage. We begin by examining the differential impacts of UVA and UVB radiation on skin cells and the role of oxidative stress in accelerating photoaging. Next, we delve into the molecular mechanisms of autophagy, including its various forms and regulatory pathways. Central to this review is the discussion of autophagy's protective functions, such as the clearance of damaged organelles and proteins, and its role in maintaining genomic integrity. Furthermore, we address the current challenges in harnessing autophagy for therapeutic purposes, including the need for selective autophagy inducers and a deeper understanding of its context-dependent effects. By synthesizing recent advancements and proposing future research directions, this review underscores the potential of autophagy modulation as a novel strategy to prevent and treat photoaging. This comprehensive analysis aims to inspire further investigation into autophagy-based interventions, offering new hope for preserving skin health in the face of environmental stressors.

Lonicerin regulates AMPK/SIRT1/autophagy pathway to attenuate heat stress intestinal injury and inhibit inflammation

Intestinal injury is one of the most prevalent complications following heat stress (HS) in both humans and animals. Autophagy has been shown to maintain intestinal homeostasis, and modulation of autophagy may help alleviate intestinal injury caused by HS. Lonicerin (LN) are flavonoids known to have enhanced autophagy and anti-inflammatory effects. However, how LN prevent intestinal damage and regulate autophagy after HS remains unknown. The aim of this study was to elucidate the potential regulatory effects of LN on intestinal inflammation and intestinal barrier function in a HS model, and to elucidate the underlying molecular mechanisms. Firstly, we searched for the same inflammatory cytokines in the drug and disease targets through network pharmacology, and in vitro and in vivo experiments showed that LN significantly inhibited the production of pro-inflammatory cytokines. Then it was demonstrated that LN alleviates HS induced intestinal mucosal barrier damage by repairing tight junctions, goblet cells, and mucins in the colon of rats, consistent with the findings of in vitro experiments. In addition, LN reversed HS-induced reduced autophagic flux and maintained autophagic homeostasis via the AMP-activated protein kinase (AMPK)-Silent information regulator 1 (SIRT1) pathway in intestinal epithelial cells and intestinal system. In summary, this study demonstrated that LN exert intestinal protective and immunomodulatory effects by inhibiting the production of pro-inflammatory cytokines, maintaining the integrity of the intestinal mucosal barrier, and the level of AMPK-SIRT1 autophagy.

Inhibition of NAMPT as a therapeutic strategy to suppress tumor growth in lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare, progressive lung disease driven by mutations in the TSC1 or TSC2 genes, leading to constitutive mTORC1 activation and uncontrolled cell proliferation. Current therapies, like rapamycin effectively stabilize disease progression but mainly exert cytostatic effects and promote autophagy, a survival mechanism in LAM cells. These limitations highlight the need for the development of innovative therapies to achieve more effective and lasting results. To explore alternative therapeutic targets, we investigated the role of nicotinamide phosphoribosyltransferase (NAMPT), a key regulator of NAD+ biosynthesis, in LAM and TSC2-deficient cells using a potent inhibitor, FK866. Our study demonstrates that FK866 depletes NAD+ levels in these cells, exerting a dual effect by activating AMPK and subsequently inhibiting mTORC1 signaling while suppressing autophagy. Unlike rapamycin, FK866 does not induce compensatory Akt activation, significantly inhibits LAM cell proliferation and induces apoptosis. Additionally, using an in vivo chicken egg chorioallantoic membrane (CAM) model, we showed that FK866 treatment significantly reduces LAM tumor growth compared to controls suggesting that NAMPT inhibition disrupts metabolic and survival pathways critical for TSC2-deficient cell viability and tumor progression. Our results establish NAMPT as a promising therapeutic target for LAM, offering a two-prong strategy to suppress tumor growth and enhance apoptosis, providing an alternative to current mTOR-based therapies.

Roles of HSP70 in autophagic protection of cardiomyocytes induced by heat acclimation: A review

In conditions of extreme high temperature, the heart is susceptible to injury induced by heat stress, which can manifest as myocardial ischemia and hypoxia, cardiomyocyte apoptosis, oxidative damage, and inflammatory responses. The normal function of cardiomyocytes is contingent upon the maintenance of protein homeostasis, and dysregulation of protein homeostasis is the underlying cause of myocardial structural damage. Autophagy and Heat Shock Protein 70 (Hsp70) play pivotal roles in regulating cellular protein quality and mitigating stress injury. Heat acclimation has been shown to induce Hsp70 expression and provide cardiomyocyte protection. However, the mechanism by which Hsp70 mediates cardiomyocyte autophagy to exert protective effects has not been fully elucidated. The objective of this review is to synthesize the existing literature on the effects of Hsp70 on autophagy during heat exposure, to explore the potential mechanisms by which Hsp70 regulates myocardial autophagy and the molecular pathways it involves, and to provide a theoretical basis for future therapeutic strategies for cardiac diseases.

Donepezil alleviates hepatic steatosis by mitigating ER stress via the AMPK/autophagy pathway

Donepezil (Do), a drug known for its ability to reduce neuronal inflammation and for its use in the treatment of Alzheimer's disease, has shown promise in combating hepatic lipid accumulation in hyperlipidemic conditions and endoplasmic reticulum (ER) stress, a factor associated with alterations in hepatic lipid metabolism. However, the mechanisms by which these problems are alleviated have not been fully elucidated. In this study, we investigated the effects of Do on hepatic lipid metabolism through both in vitro and in vivo studies. We examined the expression of proteins associated with lipogenesis and ER stress via immunoblot analysis, and hepatic lipid accumulation was assessed via oil red O staining. In addition, autophagosome formation was analyzed by counting MDC-positive cells. Our results demonstrated that Do treatment improved hepatic lipid metabolism and reduced the expression of ER stress markers, resulting in decreased lipogenic lipid deposition and apoptosis in the hepatocytes and livers of hyperlipidemic mice. Mechanistically, knocking down AMPK or inhibiting autophagy with 3-methyladenine (3 MA) attenuated the effects of Do on palmitate-exposed hepatocytes. These results suggest that Do alleviates hepatic ER stress via the AMPK/autophagy pathway and AMPK-mediated fatty acid oxidation, resulting in improved hepatic lipid metabolism and reduced hepatic steatosis and apoptosis. Our study provides evidence that Do may be a promising therapeutic approach for Alzheimer's disease patients with metabolic dysfunction-associated steatotic liver disease (MASLD).

Tricin Delays Aging and Enhances Muscle Function via Activating AMPK-Mediated Autophagy in Diverse Model Organisms

Aging leads to progressive decline in the functions of cells, tissues, and organs, severely affecting muscle performance and overall health, highlighting the urgent need for effective therapeutic agents. This study investigated the antiaging properties of tricin, a flavonoid abundant in grains, using biological models, including human fibroblasts, Caenorhabditis elegans (C. elegans), and mice. Tricin significantly alleviated the senescent phenotype in human fibroblasts induced by D-galactose (D-gal), doxorubicin, and replicative senescence, as evidenced by reduced SA-β-gal activity, downregulated senescence markers (p16, p21), and decreased SASP factors. Mechanistically, tricin binds to AMPK and activates the AMPK-mTOR-p70S6K signaling pathway, promoting autophagy and delaying cellular aging. In vivo, tricin extended lifespan, enhanced stress resistance, and improved mobility in C. elegans through aak-2/AMPK-mediated autophagy. In D-gal-induced aging mice, tricin improved muscle function, reducing p16, p21, and SASP expression in muscle tissues. These findings underscore tricin's potential as a promising antiaging therapeutic via AMPK-mediated autophagy activation.

Valosin-Containing Protein (VCP/p97) Mediates Neuroendocrine Differentiation in Prostate Cancer Cells Through Pim1 Signaling Inducing Autophagy

BACKGROUND

Neuroendocrine Prostate Cancer (NEPC) is an aggressive type of androgen-independent prostate cancer (AIPC) associated with resistance to treatment. Valosin-containing protein (VCP/p97) has been found to be overexpressed in prostate cancer (PCa) cells undergoing neuroendocrine differentiation (NED) in response to interleukin-6 (IL-6). This study explores the molecular mechanisms through which VCP/p97 contributes to the progression of NEPC.

METHODS

To investigate the role of VCP/p97 in the NED of PCa, we overexpressed the VCP/p97 in PCa cells. The molecular mechanisms underlying VCP/p97 induced NED were assessed by using western blot analysis and RT-PCR. Morphological changes were analyzed by using both bright field and confocal microscope. Lysotracker staining was performed to identify autophagy in VCP positive PCa cells.

RESULTS

In the present study, we found that VCP/p97 expression was notably higher in neuroendocrine (NE) cells NCI-H660 and PC3 than in other PCa cells. IL-6 treatment led to significant VCP/p97 overexpression in LNCaP and VCaP cells, with a marked increase in NE markers NSE and CHR-A. Inhibition of VCP/p97 using NMS-873 attenuated NED features, suggesting that VCP/p97 is required for NED progression. Moreover, VCP's role in NED is linked to its regulation via Pim1 in differentiating cells. Exogenous expression of VCP/p97 enhanced Pim1 and c-Myc expression, which were diminished upon VCP/p97 inhibition which is corroborated by reduced NED markers. Pim1 inhibition using AZD1208 and c-Myc knockdown further supported Pim1's involvement in VCP mediated NED. To promote NED, VCP/p97 regulated autophagy, as evidenced by increased LC3B and decreased SQSTM1/p62 levels upon VCP overexpression. Inhibition of VCP/p97 or autophagy disrupted NED and autophagic flux, arresting NED of LNCaP cells. Lysotracker staining and autophagic flux assays confirmed VCP's role in enhancing lysosomal-mediated autophagy and autophagolysosome formation. Furthermore, we show that AMPK activation, via LKB1 is essential for VCP/p97 mediated NED and autophagy.

CONCLUSION

VCP drives NED in PCa cells through a complex interplay involving the Pim1 axis and autophagy pathways. These findings highlight the potential of targeting VCP/p97 and its associated mechanisms as therapeutic strategies to inhibit NED progression.

Trehalose induces bladder smooth muscle hypercontractility in mice: involvement of oxidative stress and cellular senescence

Autophagy, a conserved catabolic process, is critical for cellular homeostasis and its dysregulation has been implicated in a number of conditions including hypertension, obesity and bladder dysfunctions. The autophagy inducer trehalose has shown promise in treating diseases; however, some studies have reported detrimental effects in vascular tissue under health conditions. In the bladder, the effects of trehalose remain unclear. Therefore, in the present study, male C57BL6/JUnib mice (8 weeks old) were divided into control and trehalose-treated groups (120 mg/mouse/day via gavage) for 4 weeks. After treatment, bladders were harvested for functional, biochemical, and molecular analyses. The trehalose treatment increased the bladder smooth muscle (BSM) contractility to carbachol (CCh), without altering relaxation response to isoproterenol. The CCh-induced BSM hypercontractility was completely abolished by the in vitro incubation of apocynin and diphenyleneiodonium (DPI), implicating NADPH oxidase-derived reactive oxygen species (ROS) on this process. Accordingly, increased levels of superoxide anion (O2-) were found in the urothelial layer, but not in BSM, of trehalose-treated mice. Trehalose also increased senescence-associated β-galactosidase activity in the bladder but failed to upregulate autophagy-related proteins LAMP1 and Beclin-1 in the bladder. Collectively, we show for the first time that trehalose induces BSM hypercontractility in mice, linked to increased levels of O2- and senescent cell, independently of autophagy activation. Therefore, trehalose administration is an effective model for studying BSM hypercontractility in mice, particularly associated with oxidative stress and cellular senescence.

Traditional Chinese medicine compounds modulate signaling pathways to improve cardiac-related pathology

Cardiovascular disease poses a significant risk to human health and remains the leading cause of illness and death globally, with its incidence continuing to rise. The intricate pathophysiological mechanisms of CVDs include inflammation, oxidative stress, autophagy, and myocardial fibrosis. In light of these underlying mechanisms, traditional Chinese medicine (TCM) and its constituents have demonstrated distinct advantages in managing CVDs. By exerting synergistic effects across multiple components and targets, traditional Chinese medicine can modulate the inflammatory response, mitigate oxidative stress, regulate excessive autophagy, and enhance myocardial fibrosis repair. This article reviews the latest advancements in understanding how TCM compounds regulate signaling pathways involved in the treatment of CVDs.

The role of autophagy in fibrosis: Mechanisms, progression and therapeutic potential (Review)

Various forms of tissue damage can lead to fibrosis, an abnormal reparative reaction. In the industrialized countries, 45% of deaths are attributable to fibrotic disorders. Autophagy is a highly preserved process. Lysosomes break down organelles and cytoplasmic components during autophagy. The cytoplasm is cleared of pathogens and dysfunctional organelles, and its constituent components are recycled. With the growing body of research on autophagy, it is becoming clear that autophagy and its associated mechanisms may have a role in the development of numerous fibrotic disorders. However, a comprehensive understanding of autophagy in fibrosis is still lacking and the progression of fibrotic disease has not yet been thoroughly investigated in relation to autophagy‑associated processes. The present review focused on the latest findings and most comprehensive understanding of macrophage autophagy, endoplasmic reticulum stress‑mediated autophagy and autophagy‑mediated endothelial‑to‑mesenchymal transition in the initiation, progression and treatment of fibrosis. The article also discusses treatment strategies for fibrotic diseases and highlights recent developments in autophagy‑targeted therapies.

GLP-1RAs regulate lipid metabolism and induce autophagy through AMPK/SIRT1 pathway to improve NAFLD

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of cirrhosis and a major risk factor for hepatocellular carcinoma and liver-related death. Diabetes medications have been studied as potential treatments for NAFLD. Glucagon-like peptide-1 agonists (GLP-1RAs) have been rarely reported in the treatment of NAFLD alone as an anti-diabetic drug, and its specific mechanism of action is unknown. We investigated whether the therapeutic effect of liraglutide (LRG, a representative drug of GLP-1RAs) on hepatic steatosis is related to regulating lipid metabolism and enhancing autophagy in the hepatocytes.

METHODS

We examined the effect of LRG on fat accumulation in fatty hepatocytes, and discussed its effects on enzymes related to lipid metabolism and autophagy. Meanwhile, knockdown of SIRT1 in free fatty acids(FFA)-treated cells was used to detected the influence of LRG on lipid metabolism and autophagy by regulating of AMPK/SIRT1 signaling.

RESULTS

Our findings showed that free fatty acids (FFA) induced hepatocyte steatosis, which was significantly reversed by LRG. Meanwhile, LRG significantly regulated the expression of hepatocyte lipogenesis and cytosolic lipolysis-related proteins (FAS, ACC1, ATGL, HSL, LAL). Furthermore, LRG enhanced FFA-induced suppression of autophagy and SIRT1 expression, reducing intracellular lipid accumulation. It is evident that LRG regulates lipid metabolism and induces autophagy in an (AMPK)-dependent manner. Moreover, SIRT1 knockdown inhibited the autophagy-inducing and lipid-lowering effects of LRG.

CONCLUSION

GLP-1RAs may lower hepatic steatosis by regulating lipid metabolism and enhancing autophagy in an AMPK/SIRT1-dependent manner, providing a new target for the treatment of NAFLD.

Inhibition of Ferroptosis Delays Aging and Extends Healthspan Across Multiple Species

Ferroptosis, a form of iron-dependent cell death, plays a pivotal role in age-related diseases; yet, its impact on cellular senescence and healthspan in mammals remains largely unexplored. This study identifies ferroptosis as a key regulator of cellular senescence, showing that its inhibition can significantly delay aging and extend healthspan across multiple species. During cellular senescence, ferroptosis is progressively exacerbated, marked by increased lipid peroxidation, oxidative stress, and diminished glutathione peroxidase 4 (GPX4) levels. Ferroptosis inducers such as Erastin and RSL3 accelerate senescence; while, inhibitors such as liproxstatin-1 (Lip-1) and ferrostatin-1 (Fer-1) effectively mitigate both chemically and replicatively induced senescence. In vivo, Fer-1 extends lifespan and healthspan in Caenorhabditis elegans, enhances motor function, preserves tissue integrity, and mitigates cognitive decline in both prematurely and naturally aged mice. These effects are attributed to Fer-1's upregulation of GPX4 and inhibition of ferroptosis. Notably, long-term Fer-1 treatment (over 6 months) does not adversely affect body weight or induce aging-related tissue damage but rejuvenates hematological parameters. These findings establish ferroptosis as a critical player in aging dynamics and highlight its inhibition as a promising strategy to extend healthspan and lifespan, providing valuable insights for translational approaches to combat aging and age-related decline.

Decoding microglial immunometabolism: a new frontier in Alzheimer's disease research

Alzheimer's disease (AD) involves a dynamic interaction between neuroinflammation and metabolic dysregulation, where microglia play a central role. These immune cells undergo metabolic reprogramming in response to AD-related pathology, with key genes such as TREM2, APOE, and HIF-1α orchestrating these processes. Microglial metabolism adapts to environmental stimuli, shifting between oxidative phosphorylation and glycolysis. Hexokinase-2 facilitates glycolytic flux, while AMPK acts as an energy sensor, coordinating lipid and glucose metabolism. TREM2 and APOE regulate microglial lipid homeostasis, influencing Aβ clearance and immune responses. LPL and ABCA7, both associated with AD risk, modulate lipid processing and cholesterol transport, linking lipid metabolism to neurodegeneration. PPARG further supports lipid metabolism by regulating microglial inflammatory responses. Amino acid metabolism also contributes to microglial function. Indoleamine 2,3-dioxygenase controls the kynurenine pathway, producing neurotoxic metabolites linked to AD pathology. Additionally, glucose-6-phosphate dehydrogenase regulates the pentose phosphate pathway, maintaining redox balance and immune activation. Dysregulated glucose and lipid metabolism, influenced by genetic variants such as APOE4, impair microglial responses and exacerbate AD progression. Recent findings highlight the interplay between metabolic regulators like REV-ERBα, which modulates lipid metabolism and inflammation, and Syk, which influences immune responses and Aβ clearance. These insights offer promising therapeutic targets, including strategies aimed at HIF-1α modulation, which could restore microglial function depending on disease stage. By integrating metabolic, immune, and genetic factors, this review underscores the importance of microglial immunometabolism in AD. Targeting key metabolic pathways could provide novel therapeutic strategies for mitigating neuroinflammation and restoring microglial function, ultimately paving the way for innovative treatments in neurodegenerative diseases.

AMPK Knockout Impairs the Formation of Three-Dimensional Spheroids

AMP-activated protein kinase (AMPK) is an important regulator of cellular energy homeostasis, and AMPK contributes to cell growth, apoptosis, and autophagy. Although most cell studies have been performed using two-dimensional (2D) cell culture, recent studies have demonstrated that the three-dimensional (3D) spheroid technique is helpful in various cell research fields, such as tumor biology, due to its resemblance to the 3D tissue structure. However, the role of AMPK in 3D spheroid formation has not been characterized clearly. This study used the AMPK knockout cell line to examine the role of AMPK in 3D spheroid formation and is the first report describing the generation of 3D spheroids using AMPK knockout cells. While control cells produced round spheroids with a similar length-to-width ratio, AMPK knockout produced an oval shape with a more significant length-to-width ratio. We demonstrate that AMPK knockout spheroids contain significantly more prominent lysosomes in each cell, indicating that autophagic flux is impaired in 3D spheroids. Finally, flow cytometry analysis showed that AMPK knockout spheroids contain more apoptotic cells than control cells. These results indicate that AMPK is required for efficient 3D spheroid formation.

Chikusetsu saponin IVa attenuates aging by improving autophagy and mitophagy

Chikusetsu saponin IVa (CHS) is an essential active triterpenoid saponin found in various medicinal herbs, such as Aralia taibaiensis, Panax japonicus, and Aralia elata. While multiple health benefits have been documented, the effect of CHS on aging remains unclear. By employing the D-galactose-induced aging mice and the replicative senescence of primary mouse embryonic fibroblasts (MEFs) as the aging models, we found that CHS significantly attenuated aging both in vitro and in vivo. RNA sequencing analysis revealed that CHS greatly improved autophagy and mitophagy. Corresponding to the improved mitophagy, CHS remarkably reduced mitochondrial ROS and enhanced mitochondrial respiratory function. Mitophagy inhibition and Atg 7 genetic knockout (KO) almost abolished the anti-aging effect of CHS. AMPK pathway was activated during the attenuation of aging by CHS treatment, and a specific AMPK inhibitor reversed the induction of mitophagy and autophagy, as well as the attenuation of aging by CHS. Molecular docking data indicated AMPK as the direct binding target of CHS. In conclusion, our study initially demonstrates that CHS exhibits a potent anti-aging effect both in vitro and in vivo. CHS may directly bind to AMPK and activate the AMPK-dependent pathway to enhance autophagy and mitophagy, thereby reducing mitochondrial ROS and improving mitochondrial respiratory function, contributing to the anti-aging effect. These findings offer a new clue for the promising application of CHS in the improvement of aging and aging-related diseases in the future.

Polystyrene microplastics induce hepatic lipid metabolism and energy disorder by upregulating the NR4A1-AMPK signaling pathway

Microplastics (MPs) are widespread throughout global ecosystems, and their impact on living organisms has garnered increasing attention in recent years. Research has demonstrated that exposure to different sizes (0.08-100 μm) polystyrene microplastics (PS-MPs) can disrupt hepatic lipid and energy metabolism while promoting oxidative stress. Despite these findings, the precise molecular mechanisms underlying PS-MP-induced toxicity are not fully understood. NR4A1 is known to regulate apoptosis and lipid metabolism, but few studies have explored its role in modulating hepatic lipid metabolism following PS-MP exposure. In this study, animal experiments showed that PS-MPs reduced triglyceride levels and significantly increased reactive oxygen species (ROS) in liver tissue. Transcriptional profiles of mouse liver tissues were processed and analyzed using Ingenuity Pathway Analysis (IPA) software and Gene Set Enrichment Analysis (GSEA) to identify relevant pathways and molecular signatures. The results revealed a significant upregulation in NR4A1 gene expression after exposure to PS-MPs. PS-MP accumulation in the liver activated NR4A1 and the AMPK-autophagy pathway, reducing lipid biosynthesis. In vitro study, NR4A1 knockdown in hepatocytes exposed to PS-MPs reduced the expression of AMPK and lipid metabolism-related proteins. In summary, this study indicated that PS-MPs disrupt lipid metabolism in the liver by affecting the NR4A1, leading to liver damage. Prolonged exposure to these microplastics could raise concerns about long-term liver health and the regulation of overall metabolic functions.

The Role of Autophagy in Excitotoxicity, Synaptic Mitochondrial Stress and Neurodegeneration

Brain and nervous system functions depend upon maintaining the integrity of synaptic structures over the lifetime. Autophagy, a key homeostatic quality control system, plays a central role not only in neuronal development and survival/cell death, but also in regulating synaptic activity and plasticity. Glutamate is the major excitatory neurotransmitter that activates downstream targets, with a key role in learning and memory. However, an excess of glutamatergic stimulation is pathological in stroke, epilepsy and neurodegeneration, triggering excitotoxic cell death or a sublethal process of excitatory mitochondrial calcium toxicity (EMT) that triggers dendritic retraction. Markers of autophagy and mitophagy are often elevated following excitatory neuronal injuries, with the potential to influence cell death or neurodegenerative outcomes of these injuries. Interestingly, leucine-rich repeat kinase 2 (LRRK2) and PTEN-induced kinase 1 (PINK1), two kinases linked to autophagy, mitophagy and Parkinson disease, play important roles in regulating mitochondrial calcium handling, synaptic density and function, and maturation of dendritic spines. Mutations in LRRK2, PINK1, or proteins linked to Alzheimer's disease perturb mitochondrial calcium handling to sensitize neurons to excitatory injury. While autophagy and mitophagy can play both protective and harmful roles, studies in various excitotoxicity and stroke models often implicate autophagy in a pathogenic role. Understanding the role of autophagic degradation in regulating synaptic loss and cell death following excitatory neuronal injuries has important therapeutic implications for both acute and chronic neurological disorders.

Selenium triggers AMPK-mTOR pathway to modulate autophagy related to oxidative stress of sheep Leydig cells

The objective of this study was to investigate the effect of oxidative stress induced by excessive Se on autophagy of sheep Leydig cells and its underlying mechanism. Leydig cells isolated from the testis of 8-month-old sheep were purified using a discontinuous Percoll density gradient. Cells were divided into four treatment groups (0, 2.0, 4.0 and 8.0 μmol/L of Se). After treatment with Se for 48 h, cell proliferation was detected by CCK-8 assay kit. The biochemical methods were used to evaluate the antioxidant status of Leydig cells. The mRNA transcript and protein abundance related to the AMPK-mTOR pathway and autophagy were detected by real-time PCR and western blot analysis. The results showed that the Leydig cells treated with 8.0 μmol/L Se have the lowest cell viability. The greater ROS content and lower GSH-Px activity were also observed in the Se8.0 group. The inclusion of 2.0 μmol/L Se in the medium did not affect the autophagy of Leydig cells. However, the relative abundance of ATG5 protein and LC3II/I ratio were elevated in the Se8.0 group. Oxidative stress induced by excessive Se (8.0 μmol/L) dramatically improved the abundance of key proteins related to AMPK-mTOR pathway and led to an increase of phosphorylated AMPK, mTOR and ULK1. Compared with the Se8.0 group, compound C could significantly inhibit the key molecules of AMPK-mTOR signaling pathway and mitigate the autophagy of Leydig cells induced by excessive Se. These results indicate that appropriate Se (2.0 μmol/L) can enhance the viability of sheep Leydig cells. Oxidative stress caused by Se excess can induce cell autophagy via activating AMPK-mTOR signaling pathway. The existed crosstalk between autophagy and apoptosis could decide the fate of Leydig cells. This process could play a decisive role in the maintenance of normal male fertility and spermatogenesis by affecting the number of Leydig cells in testis.

Unlocking the therapeutic potential of canagliflozin in NAFLD: Insights into AMPK/SIRT1-mediated lipophagy

Nonalcoholic fatty liver disease (NAFLD) is a rising global health problem. The antidiabetic canagliflozin (CANA) has been proposed to ameliorate the metabolic abnormalities in NAFLD.

AIM

This study aimed to explore the possible anti-NAFLD effects of CANA in rats and HepG2 cells, focusing on AMPK/SIRT1-mediated lipophagy.

METHODS

Wistar rats were assigned to four groups: control group, NAFLD group, NAFLD+CANA group, and NAFLD+CANA+chloroquine (CQ) group, where CQ served as autophagy inhibitor. HepG2 cells were also divided into four groups: control group, NAFLD group, NAFLD+CANA group, and NAFLD+CANA+compound C (Comp C) group, where Comp C served as AMPK inhibitor.

RESULTS

The histopathological examination showed that CANA alleviated hepatic and intracellular lipid deposition in rats and HepG2 cells. CANA induced lipophagy by increasing LC3-II levels and lowering both p62 and perilipin 2 levels in rats and HepG2 cells, in addition to decreasing mTOR protein expression in rats' livers. These outcomes were associated with upregulation of the lipophagy regulator Rab7 and downregulation of the ER stress-related protein CHOP. CANA enhanced autophagic engulfment of lipid droplets while decreased ER stress and mitochondrial damage in rats' livers, as demonstrated by TEM. In rats, CANA improved hyperglycemia, hyperinsulinemia, dyslipidemia, and obesity. In HepG2 cells, CANA's effects were linked to increased phosphorylated AMPK level and enhanced SIRT1 level and expression. However, blocking lipophagy in rats and AMPK in HepG2 cells markedly weakened CANA's protective effects against NAFLD.

CONCLUSION

CANA ameliorated NAFLD via enhancing AMPK/SIRT1-mediated lipophagy, suggesting its potential as a therapeutic intervention for this metabolic disorder.

Small molecule modulation of p75NTR engages the autophagy-lysosomal pathway and reduces huntingtin aggregates in cellular and mouse models of Huntington's disease

Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the HTT gene encoding a mutant huntingtin (mHtt) protein. mHtt aggregates within neurons causing degeneration primarily in the striatum. There is currently a need for disease-modifying treatments for HD. Many therapeutic studies have focused on lowering mHtt levels by reducing its production or enhancing its clearance. One way to clear mHtt aggregates is to promote autophagy, which is disrupted in HD. Our previous studies showed that the small molecule p75 neurotrophin receptor (p75NTR) ligand, LM11A-31, prevented HD-related neuropathologies and behavioral deficits in multiple HD mouse models. This study investigated whether modulating p75NTR with LM11A-31, would reduce mHtt aggregates via autophagic/lysosomal mechanisms in HD models. LM11A-31 decreased mHtt aggregates in human neuroblastoma SH-SY5Y cells expressing mHtt (exon 1 with 74 CAG repeats) and in the striatum of R6/2 and zQ175dn mouse models of HD. The LM11A-31 associated decrease in mHtt aggregates in vitro was accompanied by increased autophagic/lysosomal activity as indicated by altered levels of relevant markers including p62/SQSTM1 and the lysosomal protease, mature cathepsin D, and increased autophagy flux. In R6/2 and/or zQ175dn striatum, LM11A-31 increased AMPK activation, normalized p62/SQSTM1 and LC3II levels, and enhanced LAMP1 and decreased LC3B association with mHtt. Thus, LM11A-31 reduces mHtt aggregates and may do so via engaging autophagy/lysosomal systems. LM11A-31 has successfully completed a Phase 2a clinical trial for mild-to-moderate Alzheimer's disease and our results here strengthen its potential as a candidate for HD clinical testing.

Crosstalk Between Autophagy and Oxidative Stress in Hematological Malignancies: Mechanisms, Implications, and Therapeutic Potential

Autophagy is a fundamental cellular process that maintains homeostasis by degrading damaged components and regulating stress responses. It plays a crucial role in cancer biology, including tumor progression, metastasis, and therapeutic resistance. Oxidative stress, similarly, is key to maintaining cellular balance by regulating oxidants and antioxidants, with its disruption leading to molecular damage. The interplay between autophagy and oxidative stress is particularly significant, as reactive oxygen species (ROS) act as both inducers and by-products of autophagy. While autophagy can function as a tumor suppressor in early cancer stages, it often shifts to a pro-tumorigenic role in advanced disease, aiding cancer cell survival under adverse conditions such as hypoxia and nutrient deprivation. This dual role is mediated by several signaling pathways, including PI3K/AKT/mTOR, AMPK, and HIF-1α, which coordinate the balance between autophagic activity and ROS production. In this review, we explore the mechanisms by which autophagy and oxidative stress interact across different hematological malignancies. We discuss how oxidative stress triggers autophagy, creating a feedback loop that promotes tumor survival, and how autophagic dysregulation leads to increased ROS accumulation, exacerbating tumorigenesis. We also examine the therapeutic implications of targeting the autophagy-oxidative stress axis in cancer. Current strategies involve modulating autophagy through specific inhibitors, enhancing ROS levels with pro-oxidant compounds, and combining these approaches with conventional therapies to overcome drug resistance. Understanding the complex relationship between autophagy and oxidative stress provides critical insights into novel therapeutic strategies aimed at improving cancer treatment outcomes.

The di-leucine motif in the host defense peptide LL-37 is essential for initiation of autophagy in human macrophages

The human cathelicidin peptide LL-37 induces autophagy in human macrophages. Different post-translational modifications (PTMs) such as citrullination, acetylation, and formylation impact LL-37, yet their effect on autophagy remains unknown. Thus, we set out to study how the cellular source could impact PTM of LL-37 and subsequent effects on autophagy initiation. Neutrophil-released LL-37 failed to induce autophagy, unlike macrophage-released LL-37. Mass spectrometry analysis revealed modifications on neutrophil-derived LL-37, especially at the N terminus, while macrophage-derived LL-37 remained mostly native. Native LL-37 initiated autophagy, while formylated and acetylated versions did not. Truncated peptides lacking the N-terminal di-leucine motif or substituted with di-alanine did not initiate autophagy. Native LL-37 failed to initiate autophagy in macrophages with genetic inactivation of dipeptidyl peptidase-1. An intact N-terminal di-leucine motif in LL-37 was crucial for autophagy initiation, and modifications abrogated the effects. This pathway presents a novel way to regulate the effects of LL-37 in infection or inflammation.

mTORC1, the maestro of cell metabolism and growth

The mechanistic target of rapamycin (mTOR) pathway senses and integrates various environmental and intracellular cues to regulate cell growth and proliferation. As a key conductor of the balance between anabolic and catabolic processes, mTOR complex 1 (mTORC1) orchestrates the symphonic regulation of glycolysis, nucleic acid and lipid metabolism, protein translation and degradation, and gene expression. Dysregulation of the mTOR pathway is linked to numerous human diseases, including cancer, neurodegenerative disorders, obesity, diabetes, and aging. This review provides an in-depth understanding of how nutrients and growth signals are coordinated to influence mTOR signaling and the extensive metabolic rewiring under its command. Additionally, we discuss the use of mTORC1 inhibitors in various aging-associated metabolic diseases and the current and future potential for targeting mTOR in clinical settings. By deciphering the complex landscape of mTORC1 signaling, this review aims to inform novel therapeutic strategies and provide a road map for future research endeavors in this dynamic and rapidly evolving field.

Emerging targets in amyotrophic lateral sclerosis (ALS): The promise of ATP-binding cassette (ABC) transporter modulation

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative primarily affecting motor neurons, leading to disability and neuronal death, and ATP-Binding Cassette (ABC) transporter due to their role in drug efflux and modulation of various cellular pathways contributes to the pathogenesis of ALS. In this article, we extensively investigated various molecular and mechanistic pathways linking ALS transporter to the pathogenesis of ALS; this involves inflammatory pathways such as Mitogen-Activated Protein Kinase (MAPK), Phosphatidylinositol-3-Kinase/Protein Kinase B (PI3K/Akt), Toll-Like Receptor (TLR), Glycogen Synthase Kinase 3β (GSK-3β), Nuclear Factor Kappa-B (NF-κB), and Cyclooxygenase (COX). Oxidative pathways such as Astrocytes, Glutamate, Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Sirtuin 1 (SIRT-1), Forkhead box protein O (FOXO), Extracellular signal-regulated kinase (ERK). Additionally, we delve into the role of autophagic pathways like TAR DNA-binding protein 43 (TDP-43), AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), and lastly, the apoptotic pathways. Furthermore, by understanding these intricate interactions, we aim to develop novel therapeutic strategies targeting ABC transporters, improving drug delivery, and ultimately offering a promising avenue for treating ALS.

Small-molecule inhibitors of WNT signalling in cancer therapy and their links to autophagy and apoptosis

Cancer represents an intricate and heterogeneous ailment that evolves from a multitude of epigenetic and genetic variations that disrupt normal cellular function. The WNT/β-catenin pathway is essential in maintaining the balance between cell renewal and differentiation in various tissues. Abnormal activation of this pathway can lead to uncontrolled cell growth and initiate cancer across a variety of tissues such as the colon, skin, liver, and ovary. It enhances characteristics that lead to cancer progression, including angiogenesis, invasion and metastasis. Processes like autophagy and apoptosis which regulate cell death and play a crucial role in maintaining cellular equilibrium are also intimately linked with WNT/ β-catenin pathway. Thus, targeting WNT pathway has become a key strategy in developing antitumor therapies. Employing small molecule inhibitors has emerged as a targeted therapy to improve the clinical outcome compared to conventional cancer treatments. Many strategies using small molecule inhibitors for modulating the WNT/β-catenin pathway, such as hindering WNT ligands' secretion or interaction, disrupting receptor complex, and blocking the nuclear translocation of β-catenin have been investigated. These interventions have shown promise in both preclinical and clinical settings. This review provides a comprehensive understanding of the role of WNT/β-catenin signalling pathway's role in cancer, emphasizing its regulation of autophagy and apoptosis. Our goal is to highlight the potential of specific small molecule inhibitors targeting this pathway, fostering the development of novel, tailored cancer treatments.

Chlorogenic acid alleviates cadmium-induced neuronal injury in chicken cerebral cortex by inhibiting incomplete autophagy mediated by AMPK-ULK1 pathway

Cadmium (Cd) is an environmental pollutant that has neurotoxic properties, which poses serious threats to human health and the development of poultry farming. Chlorogenic acid (CGA) is a dietary polyphenol exhibit various biological activities such as antioxidant, anti-inflammatory, and autophagy regulation. In addition, CGA can penetrate the blood-brain barrier and exert neuroprotective effects. This study explored the mechanism of CGA in alleviating Cd-induced cerebral cortical neuron injury in chickens. The results showed that in vivo, CGA reduced the Cd level and alleviated Cd-induced histopathological and ultrastructural damages in the chicken cerebral cortex. Further research has found that CGA alleviated Cd-induced incomplete autophagy and activation of the AMPK-ULK1 pathway. In vitro, AMPK inhibitors (Compound C) could alleviate Cd-induced incomplete autophagy in chicken cerebral cortical neurons. In addition, CGA alleviated the decreased viability, incomplete autophagy, and activation of the AMPK-ULK1 pathway induced by Cd in chicken cerebral cortical neurons. In summary, CGA can alleviate Cd-induced cerebral cortical neuron injury in chickens, which is related to CGA alleviating Cd-induced incomplete autophagy by inhibiting the AMPK-ULK1 pathway.

PKA regulates autophagy through lipolysis during fasting

Autophagy is a crucial intracellular degradation process that provides energy and supports nutrient deprivation adaptation. However, the mechanisms by which these cells detect lipid scarcity and regulate autophagy are poorly understood. In this study, we demonstrate that protein kinase A (PKA)-dependent lipolysis delays autophagy initiation during short-term nutrient deprivation by inhibiting AMP-activated protein kinase (AMPK). Using coherent anti-Stokes Raman spectroscopy, we visualized free fatty acids (FFAs) in vivo and observed that lipolysis-derived FFAs were used before the onset of autophagy. Our data suggest that autophagy is triggered when the supply of FFAs is insufficient to meet energy demands. Furthermore, PKA activation promotes lipolysis and suppresses AMPK-driven autophagy during early fasting. Disruption of this regulatory axis impairs motility and reduces the lifespan of Caenorhabditis elegans during fasting. These findings establish PKA as a critical regulator of catabolic pathways, prioritizing lipolysis over autophagy by modulating AMPK activity to prevent premature autophagic degradation during transient nutrient deprivation.

Myeloid Cell-Specific Deletion of AMPKα1 Worsens Ocular Bacterial Infection by Skewing Macrophage Phenotypes

AMP-activated protein kinase (AMPK) plays a crucial role in governing essential cellular functions such as growth, proliferation, and survival. Previously, we observed increased vulnerability to bacterial (Staphylococcus aureus) endophthalmitis in global AMPKα1 knockout mice. In this study, we investigated the specific involvement of AMPKα1 in myeloid cells using LysMCre;AMPKα1fl mice. Our findings revealed that whereas endophthalmitis resolved in wild-type C57BL/6 mice, the severity of the disease progressively worsened in AMPKα1-deficient mice over time. Moreover, the intraocular bacterial load and inflammatory mediators (e.g., IL-1β, TNF-α, IL-6, and CXCL2) were markedly elevated in the LysMCre;AMPKα1fl mice. Mechanistically, the deletion of AMPKα1 in myeloid cells skewed macrophage polarization toward the inflammatory M1 phenotype and impaired the phagocytic clearance of S. aureus by macrophages. Notably, transferring AMPK-competent bone marrow from wild-type mice to AMPKα1 knockout mice preserved retinal function and mitigated the severity of endophthalmitis. Overall, our study underscores the role of myeloid-specific AMPKα1 in promoting the resolution of inflammation in the eye during bacterial infection. Hence, therapeutic strategies aimed at restoring or enhancing AMPKα1 activity could improve visual outcomes in endophthalmitis and other ocular infections.

Impact of Physical Activity on Cellular Metabolism Across Both Neurodegenerative and General Neurological Conditions: A Narrative Review

BACKGROUND

Regular physical activity plays a crucial role in modulating cellular metabolism and mitigating the progression of neurodegenerative diseases such as Alzheimer's, Parkinson's, and Multiple Sclerosis.

OBJECTIVE

The objective of this review is to evaluate the molecular mechanisms by which exercise influences cellular metabolism, with a focus on its potential as a therapeutic intervention for neurological disorders.

METHODS

A comprehensive literature review was conducted using peer-reviewed scientific articles, with a focus on the period between 2015 and 2024, to analyze the effects of exercise on mitochondrial function, oxidative stress, and metabolic health.

RESULTS

The findings indicate that exercise promotes mitochondrial biogenesis, enhances oxidative phosphorylation, and reduces reactive oxygen species, contributing to improved energy production and cellular resilience. These metabolic adaptations are associated with delayed disease progression and reduced symptoms in patients with neurodegenerative conditions. Additionally, integrating exercise with nutritional strategies may further enhance therapeutic outcomes by addressing metabolic disturbances comprehensively.

CONCLUSIONS

This review concludes that personalized exercise protocols should be developed to optimize metabolic benefits for patients with neurological diseases, while future research should focus on biomarker development for individualized treatment approaches. These findings highlight the importance of non-pharmacological interventions in managing neurodegenerative diseases.

An updated outlook on autophagy mechanism and how it supports acute myeloid leukemia maintenance

The gradual acquisition of genetic and epigenetic disturbances bestows malignant traits upon hematopoietic stem cells, subverting them into a founder and reservoir cell for de novo acute myeloid leukemia (AML) known as leukemic stem cells (LSC). Beyond its molecular heterogeneity, AML is also characterized by rewiring biological processes to support its onset and maintenance. LSC were observed to inherently and actively trigger mitochondrial turnover through selective autophagic removal such that impairing the process led to cell differentiation at the expense of its stemness. This review provides a current take on autophagy regulation mechanisms according to the current molecular characterization of the process; describes autophagy as a drug resistance mechanism, and a pivotal mechanism whereby LSC harmonize their strong reliance on mitochondrial respiration to obtain energy, and their necessity for lower internal oxidative stress to avoid exhaustion. Therefore, targeting autophagy presents a promising strategy to promote long-term remissions in AML.

No energy, no autophagy-Mechanisms and therapeutic implications of autophagic response energy requirements

Autophagy is a lysosome-mediated self-degradation process of central importance for cellular quality control. It also provides macromolecule building blocks and substrates for energy metabolism during nutrient or energy deficiency, which are the main stimuli for autophagy induction. However, like most biological processes, autophagy itself requires ATP, and there is an energy threshold for its initiation and execution. We here present the first comprehensive review of this often-overlooked aspect of autophagy research. The studies in which ATP deficiency suppressed autophagy in vitro and in vivo were classified according to the energy pathway involved (oxidative phosphorylation or glycolysis). A mechanistic insight was provided by pinpointing the critical ATP-consuming autophagic events, including transcription/translation/interaction of autophagy-related molecules, autophagosome formation/elongation, autophagosome fusion with the lysosome, and lysosome acidification. The significance of energy-dependent fine-tuning of autophagic response for preserving the cell homeostasis, and potential implications for the therapy of cancer, autoimmunity, metabolic disorders, and neurodegeneration are discussed.

Neuroprotective effects of G9a inhibition through modulation of peroxisome-proliferator activator receptor gamma-dependent pathways by miR-128

JOURNAL/nrgr/04.03/01300535-202419110-00033/figure1/v/2024-03-08T184507Z/r/image-tiff Dysregulation of G9a, a histone-lysine N-methyltransferase, has been observed in Alzheimer's disease and has been correlated with increased levels of chronic inflammation and oxidative stress. Likewise, microRNAs are involved in many biological processes and diseases playing a key role in pathogenesis, especially in multifactorial diseases such as Alzheimer's disease. Therefore, our aim has been to provide partial insights into the interconnection between G9a, microRNAs, oxidative stress, and neuroinflammation. To better understand the biology of G9a, we compared the global microRNA expression between senescence-accelerated mouse-prone 8 (SAMP8) control mice and SAMP8 treated with G9a inhibitor UNC0642. We found a downregulation of miR-128 after a G9a inhibition treatment, which interestingly binds to the 3' untranslated region (3'-UTR) of peroxisome-proliferator activator receptor γ (PPARG) mRNA. Accordingly, Pparg gene expression levels were higher in the SAMP8 group treated with G9a inhibitor than in the SAMP8 control group. We also observed modulation of oxidative stress responses might be mainly driven Pparg after G9a inhibitor. To confirm these antioxidant effects, we treated primary neuron cell cultures with hydrogen peroxide as an oxidative insult. In this setting, treatment with G9a inhibitor increases both cell survival and antioxidant enzymes. Moreover, up-regulation of PPARγ by G9a inhibitor could also increase the expression of genes involved in DNA damage responses and apoptosis. In addition, we also described that the PPARγ/AMPK axis partially explains the regulation of autophagy markers expression. Finally, PPARγ/GADD45α potentially contributes to enhancing synaptic plasticity and neurogenesis after G9a inhibition. Altogether, we propose that pharmacological inhibition of G9a leads to a neuroprotective effect that could be due, at least in part, by the modulation of PPARγ-dependent pathways by miR-128.

Early Cardiac Ischemia-Reperfusion Injury: Interactions of Autophagy with Galectin-3 and Oxidative Stress

Background: Cardiovascular diseases are the leading cause of death worldwide, including the United Arab Emirates. Ischemia-reperfusion (IR) injury results in the death of cardiac myocytes that were viable immediately before myocardial reperfusion. We aim to investigate the role of galectin-3 (Gal-3) in autophagy during ischemia-reperfusion injuries. Methods: Male C57B6/J and Gal-3 knockout (KO) mice were used for the murine model of IR injury. Heart samples and serum were collected 24 h post-IR and were processed for immunohistochemical and immunofluorescent labeling and an enzyme-linked immunosorbent assay. Results: There was a significant increase in left ventricle (LV) concentrations of Gal-3 in Gal-3 wild-type mice compared to sham mice. There were significantly higher concentrations of LV autophagy proteins and phospho-AMPK in IR Gal-3 KO mice than in IR Gal-3 wild-type mice, compared to lower concentrations of LV phospho-mTOR and p62 in IR Gal-3 KO than in IR wild-type mice. Antioxidant activities were higher in the LVs of IR Gal-3 wild-type mice, while oxidative stress was higher in the LVs of IR Gal-3 KO mice. Conclusions: Our study supports the interaction of Gal-3 with autophagy proteins, oxidative stress, and antioxidant proteins and demonstrates that the absence of Gal-3 can enhance autophagy in the heart after IR injury.

The AMPK-mTOR Pathway Is Inhibited by Chaihu Shugan Powder, Which Relieves Nonalcoholic Steatohepatitis by Suppressing Autophagic Ferroptosis

Nonalcoholic steatohepatitis (NASH) is the advanced stage of nonalcoholic fatty liver disease (NAFLD), which is distinguished by the accumulation of fat in the liver, damage to liver cells, and inflammation. Chaihu Shugan powder (CSP), a renowned traditional Chinese medicine (TCM) blend extensively utilized in China to address liver disease, has demonstrated its efficacy in reducing lipid buildup and effectively combating inflammation. Hence, the primary objective of this research is to examine the impacts and possible mechanisms of CSP on NASH through assessments of liver histopathology, lipidomic analysis, and gene expression. To induce a mouse model of NASH, we employed a diet which deficient in methionine and choline, known as methionine-choline deficient (MCD) diet. Initially, we examined the impact of administering CSP to NASH mice by assessing the levels of serum and liver indicators. We found that CSP was able to reduce lipid buildup and inflammation in mice. In addition, a total of 1009 genes exhibited enrichment in both the autophagy and ferroptosis pathways. The liver protein levels of Adenosine monophosphate-activated protein kinase-mammalian target of rapamycin (AMPK-mTOR)-mediated autophagy and ferroptosis markers, such as p-AMPKα/AMPKα, p-mTOR/mTOR, Beclin-1, microtubule associated protein 1 light chain 3 gamma (LC3), p62 (sequestosome 1 [SQSTM1/p62]), Kelch-like ECH-associated protein 1 (KEAP1), nuclear factor erythroid 2-related factor 2 (Nrf-2), ferritin heavy chain 1 (FTH1), and glutathione peroxidase 4 (GPX4), were restored by CSP. Furthermore, our findings indicated that the suppression of autophagy had a repressive impact on the occurrence of ferroptosis in the mouse model, indicating that autophagy activation likely plays a role in mediating ferroptosis in NASH.

Activation of AMPK/SIRT1/FOXO3a signaling by BMS-477118 (saxagliptin) mitigates chronic colitis in rats: uncovering new anti-inflammatory and antifibrotic roles

Ulcerative colitis (UC) is a debilitating chronic disease marked by persistent inflammation and intestinal fibrosis. Despite the availability of various treatments, many patients fail to achieve long-term remission, underscoring a significant unmet therapeutic need. BMS-477118, a reversible inhibitor of dipeptidyl peptidase 4 (DPP4), has demonstrated anti-inflammatory properties in preclinical and clinical studies with minimal adverse effects compared to other antidiabetic agents. However, the potential benefits of BMS-477118 in chronic UC have not yet been explored. In this study, we aimed to investigate the effects of BMS-477118 in rats subjected to chronic dextran sodium sulfate (DSS) administration. Our findings indicate that BMS-477118 activates the interconnected positive feedback loop involving AMPK, SIRT1, and FOXO3a, improving histological appearance in injured rat colons. BMS-477118 also reduced fibrotic changes associated with the chronic nature of the animal model, alleviated macroscopic damage and disease severity, and improved the colon weight-to-length ratio. Additionally, BMS-477118 prevented DSS-induced weight loss and enhanced tight junction proteins. These effects, in conjunction with reduced oxidative stress and its potential anti-inflammatory, antiapoptotic, and autophagy-inducing properties, fostered prolonged survival in rats with chronic UC. To conclude, BMS-477118 has the potential to activate the AMPK/SIRT1/FOXO3a signaling pathway in inflamed colons. These results suggest that the AMPK/SIRT1/FOXO3a pathway could be a new therapeutic target for UC. Further research is mandatory to explore the therapeutic possibilities of this pathway. Additionally, continued studies on the therapeutic potential of BMS-477118 and other DPP4 inhibitors are promising for creating new treatments for various conditions, including UC in diabetic patients.

Repurposing ezetimibe as a neuroprotective agent in a rotenone-induced Parkinson's disease model in rats: Role of AMPK/SIRT-1/PGC-1α signaling and autophagy

As a severe neurological disorder, Parkinson's disease (PD) is distinguished by dopaminergic neuronal degeneration in the substantia nigra (SN), culminating in motor impairments. Several studies have shown that activation of the AMPK/SIRT1/PGC1α pathway contributes to an increase in mitochondrial biogenesis and is a promising candidate for the management of PD. Furthermore, turning on the AMPK/SIRT1/PGC1α pathway causes autophagy activation, which is fundamental for maintaining neuronal homeostasis. Interestingly, ezetimibe is an antihyperlipidemic agent that was recently reported to possess pleiotropic properties in neurology by triggering the phosphorylation and activation of AMPK. Thus, our study aimed to investigate the neuroprotective potential of ezetimibe in rats with rotenone-induced PD by activating AMPK. Adult male Wistar rats received rotenone (1.5 mg/kg, s.c.) every other day for 21 days to induce experimental PD. Rats were treated with ezetimibe (5 mg/kg/day, i.p.) 1 h before rotenone. Ezetimibe ameliorated the motor impairments in open field, rotarod and grip strength tests, restored striatal dopamine and tyrosine hydroxylase in the SN, up-regulated p-AMPK, SIRT1, and PGC1α striatal expression, upsurged the expression of ULK1, beclin1, and LC3II/I, reduced Bax/Bcl2 ratio, and alleviated rotenone-induced histopathological changes in striatum and SN. Our findings also verified the contribution of AMPK activation to the neuroprotective effect of ezetimibe by using the AMPK inhibitor dorsomorphin. Together, this work revealed that ezetimibe exerts a neuroprotective impact in rotenone-induced PD by activating AMPK/SIRT-1/PGC-1α signaling, enhancing autophagy, and attenuating apoptosis. Thus, ezetimibe's activation of AMPK could hold significant therapeutic promise for PD management.

The roles and mechanisms of endoplasmic reticulum stress-mediated autophagy in animal viral infections

The endoplasmic reticulum (ER) is a unique organelle responsible for protein synthesis and processing, lipid synthesis in eukaryotic cells, and the replication of many animal viruses is closely related to ER. A considerable number of viral proteins are synthesised during viral infection, resulting in the accumulation of unfolded and misfolded proteins in ER, which in turn induces endoplasmic reticulum stress (ERS). ERS further drives three signalling pathways (PERK, IRE1, and ATF6) of the cellular unfolded protein response (UPR) to respond to the ERS. In numerous studies, ERS has been shown to mediate autophagy, a highly conserved cellular degradation mechanism to maintain cellular homeostasis in eukaryotic cells, through the UPR to restore ER homeostasis. ERS-mediated autophagy is closely linked to the occurrence and development of numerous viral diseases in animals. Host cells can inhibit viral replication by regulating ERS-mediated autophagy, restoring the ER's normal physiological process. Conversely, many viruses have evolved strategies to exploit ERS-mediated autophagy to achieve immune escape. These strategies include the regulation of PERK-eIF2α-Beclin1, PERK-eIF2α-ATF4-ATG12, IRE1α-JNK-Beclin1, and other signalling pathways, which provide favourable conditions for the replication of animal viruses in host cells. The ERS-mediated autophagy pathway has become a hot topic in animal virological research. This article reviews the most recent research regarding the regulatory functions of ERS-mediated autophagy pathways in animal viral infections, emphasising the underlying mechanisms in the context of different viral infections. Furthermore, it considers the future direction and challenges in the development of ERS-mediated autophagy targeting strategies for combating animal viral diseases, which will contribute to unveiling their pathogenic mechanism from a new perspective and provide a scientific reference for the discovery and development of new antiviral drugs and preventive strategies.

Application and research progress of cordycepin in the treatment of tumours (Review)

Cordycepin is a nucleoside molecule found in Cordyceps sinensis and can be obtained through chemical synthesis and biotransformation. Cordycepin has been extensively studied and has been shown to have antitumour activity. This activity includes effects on the autophagy process and inhibition of the MAPK/ERK and Hedgehog pathways. Ultimately, the inhibitory effect of cordycepin on tumour cells is due to the interplay of these effects. Cordycepin was shown to enhance the therapeutic effects of radiotherapy. There is increasing evidence indicating that cordycepin plays an anticancer role in the treatment of various cancers. The present review aims to provide a clear understanding of the antitumour mechanisms of cordycepin and discuss its present application in the treatment of tumours. This information can be an important theoretical basis and provide clinical guidance for the further development of cordycepin as an antitumour drug.

A2AR antagonists triggered the AMPK/m-TOR autophagic pathway to reverse the calcium-dependent cell damage in 6-OHDA induced model of PD

Calcium dyshomeostasis, oxidative stress, autophagy and apoptosis are the pathogenesis of selective dopaminergic neuronal loss in Parkinson's disease (PD). Earlier, we reported that A2A R modulates IP3-dependent intracellular Ca2+ signalling via PKA. Moreover, A2A R antagonist has been reported to reduce oxidative stress and apoptosis in PD models, however intracellular Ca2+ ([Ca2+]i) dependent autophagy regulation in the 6-OHDA model of PD has not been explored. In the present study, we investigated the A2A R antagonists mediated neuroprotective effects in 6-OHDA-induced primary midbrain neuronal (PMN) cells and unilateral lesioned rat model of PD. 6-OHDA-induced oxidative stress (ROS and superoxide) and [Ca2+]i was measured using Fluo4AM, DCFDA and DHE dye respectively. Furthermore, autophagy was assessed by Western blot of p-m-TOR/mTOR, p-AMPK/AMPK, LC3I/II, Beclin and β-actin. Apoptosis was measured by Annexin V-APC-PI detection and Western blot of Bcl2, Bax, caspase3 and β-actin. Dopamine levels were measured by Dopamine ELISA kit and Western blot of tyrosine hydroxylase. Our results suggest that 6-OHDA-induced PMN cell death occurred due to the interruption of [Ca2+]i homeostasis, accompanied by activation of autophagy and apoptosis. A2A R antagonists prevented 6-OHDA-induced neuronal cell death by decreasing [Ca2+]i overload and oxidative stress. In addition, we found that A2A R antagonists upregulated mTOR phosphorylation and downregulated AMPK phosphorylation thereby reducing autophagy and apoptosis both in 6-OHDA induced PMN cells and 6-OHDA unilateral lesioned rat model. In conclusion, A2A R antagonists alleviated 6-OHDA toxicity by modulating [Ca2+]i signalling to inhibit autophagy mediated by the AMPK/mTOR pathway.

Unexpected roles for AMPK in the suppression of autophagy and the reactivation of MTORC1 signaling during prolonged amino acid deprivation

AMPK promotes catabolic and suppresses anabolic cell metabolism to promote cell survival during energetic stress, in part by inhibiting MTORC1, an anabolic kinase requiring sufficient levels of amino acids. We found that cells lacking AMPK displayed increased apoptotic cell death during nutrient stress caused by prolonged amino acid deprivation. We presumed that impaired macroautophagy/autophagy explained this phenotype, as a prevailing view posits that AMPK initiates autophagy (often a pro-survival response) through phosphorylation of ULK1. Unexpectedly, however, autophagy remained unimpaired in cells lacking AMPK, as monitored by several autophagic readouts in several cell lines. More surprisingly, the absence of AMPK increased ULK1 signaling and MAP1LC3B/LC3B lipidation during amino acid deprivation while AMPK-mediated phosphorylation of ULK1 S555 (a site proposed to initiate autophagy) decreased upon amino acid withdrawal or pharmacological MTORC1 inhibition. In addition, activation of AMPK with compound 991, glucose deprivation, or AICAR blunted autophagy induced by amino acid withdrawal. These results demonstrate that AMPK activation and glucose deprivation suppress autophagy. As AMPK controlled autophagy in an unexpected direction, we examined how AMPK controls MTORC1 signaling. Paradoxically, we observed impaired reactivation of MTORC1 in cells lacking AMPK upon prolonged amino acid deprivation. Together these results oppose established views that AMPK promotes autophagy and inhibits MTORC1 universally. Moreover, they reveal unexpected roles for AMPK in the suppression of autophagy and the support of MTORC1 signaling in the context of prolonged amino acid deprivation. These findings prompt a reevaluation of how AMPK and its control of autophagy and MTORC1 affect health and disease.

MicroRNAs in Hepatocellular Carcinoma Pathogenesis: Insights into Mechanisms and Therapeutic Opportunities

Hepatocellular carcinoma (HCC) presents a significant global health burden, with alarming statistics revealing its rising incidence and high mortality rates. Despite advances in medical care, HCC treatment remains challenging due to late-stage diagnosis, limited effective therapeutic options, tumor heterogeneity, and drug resistance. MicroRNAs (miRNAs) have attracted substantial attention as key regulators of HCC pathogenesis. These small non-coding RNA molecules play pivotal roles in modulating gene expression, implicated in various cellular processes relevant to cancer development. Understanding the intricate network of miRNA-mediated molecular pathways in HCC is essential for unraveling the complex mechanisms underlying hepatocarcinogenesis and developing novel therapeutic approaches. This manuscript aims to provide a comprehensive review of recent experimental and clinical discoveries regarding the complex role of miRNAs in influencing the key hallmarks of HCC, as well as their promising clinical utility as potential therapeutic targets.

Role of Autophagy and AMPK in Cancer Stem Cells: Therapeutic Opportunities and Obstacles in Cancer

Cancer stem cells represent a resilient subset within the tumor microenvironment capable of differentiation, regeneration, and resistance to chemotherapeutic agents, often using dormancy as a shield. Their unique properties, including drug resistance and metastatic potential, pose challenges for effective targeting. These cells exploit certain metabolic processes for their maintenance and survival. One of these processes is autophagy, which generally helps in energy homeostasis but when hijacked by CSCs can help maintain their stemness. Thus, it is often referred as an Achilles heel in CSCs, as certain cancers tend to depend on autophagy for survival. Autophagy, while crucial for maintaining stemness in cancer stem cells (CSCs), can also serve as a vulnerability in certain contexts, making it a complex target for therapy. Regulators of autophagy like AMPK (5' adenosine monophosphate-activated protein kinase) also play a crucial role in maintaining CSCs stemness by helping CSCs in metabolic reprogramming in harsh environments. The purpose of this review is to elucidate the interplay between autophagy and AMPK in CSCs, highlighting the challenges in targeting autophagy and discussing therapeutic strategies to overcome these limitations. This review focuses on previous research on autophagy and its regulators in cancer biology, particularly in CSCs, addresses the remaining unanswered questions, and potential targets for therapy are also brought to attention.

Physiological functions of ULK1/2

UNC-51-like kinases 1 and 2 (ULK1/2) are serine/threonine kinases that are best known for their evolutionarily conserved role in the autophagy pathway. Upon sensing the nutrient status of a cell, ULK1/2 integrate signals from upstream cellular energy sensors such as mTOR and AMPK and relay them to the downstream components of the autophagy machinery. ULK1/2 also play indispensable roles in the selective autophagy pathway, removing damaged mitochondria, invading pathogens, and toxic protein aggregates. Additional functions of ULK1/2 have emerged beyond autophagy, including roles in protein trafficking, RNP granule dynamics, and signaling events impacting innate immunity, axon guidance, cellular homeostasis, and cell fate. Therefore, it is no surprise that alterations in ULK1/2 expression and activity have been linked with pathophysiological processes, including cancer, neurological disorders, and cardiovascular diseases. Growing evidence suggests that ULK1/2 function as biological rheostats, tuning cellular functions to intra and extra-cellular cues. Given their broad physiological relevance, ULK1/2 are candidate targets for small molecule activators or inhibitors that may pave the way for the development of therapeutics for the treatment of diseases in humans.

Complex Interplay between DNA Damage and Autophagy in Disease and Therapy

Cancer, a multifactorial disease characterized by uncontrolled cellular proliferation, remains a global health challenge with significant morbidity and mortality. Genomic and molecular aberrations, coupled with environmental factors, contribute to its heterogeneity and complexity. Chemotherapeutic agents like doxorubicin (Dox) have shown efficacy against various cancers but are hindered by dose-dependent cytotoxicity, particularly on vital organs like the heart and brain. Autophagy, a cellular process involved in self-degradation and recycling, emerges as a promising therapeutic target in cancer therapy and neurodegenerative diseases. Dysregulation of autophagy contributes to cancer progression and drug resistance, while its modulation holds the potential to enhance treatment outcomes and mitigate adverse effects. Additionally, emerging evidence suggests a potential link between autophagy, DNA damage, and caretaker breast cancer genes BRCA1/2, highlighting the interplay between DNA repair mechanisms and cellular homeostasis. This review explores the intricate relationship between cancer, Dox-induced cytotoxicity, autophagy modulation, and the potential implications of autophagy in DNA damage repair pathways, particularly in the context of BRCA1/2 mutations.

Importance of Energy, Dietary Protein Sources, and Amino Acid Composition in the Regulation of Metabolism: An Indissoluble Dynamic Combination for Life

PURPOSE

This paper aims to present a unique perspective that emphasizes the intricate interplay between energy, dietary proteins, and amino acid composition, underscoring their mutual dependence for health-related considerations. Energy and protein synthesis are fundamental to biological processes, crucial for the sustenance of life and the growth of organisms.

METHODS AND RESULTS

We explore the intricate relationship between energy metabolism, protein synthesis, regulatory mechanisms, protein sources, amino acid availability, and autophagy in order to elucidate how these elements collectively maintain cellular homeostasis. We underscore the vital role this dynamic interplay has in preserving cell life.

CONCLUSIONS

A deeper understanding of the link between energy and protein synthesis is essential to comprehend fundamental cellular processes. This insight could have a wide-ranging impact in several medical fields, such as nutrition, metabolism, and disease management.

Genipin Activates Autophagy and Promotes Myoblast Differentiation by Activating AMPK Pathway

Cultured meat technology is expected to solve problems such as resource shortages and environmental pollution, but the muscle fiber differentiation efficiency of cultured meat is low. Genipin is the active compound derived from Gardenia jasminoides Ellis, which has a variety of activities. Additionally, genipin serves as a noncytotoxic agent for cross-linking, which is suitable as a foundational scaffold for in vitro tissue regeneration. However, the impact of genipin on myoblast differentiation remains to be studied. The research revealed that genipin was found to improve the differentiation efficiency of myoblasts. Genipin improved mitochondrial membrane potential by activating the AMPK signaling pathway of myoblasts, promoting mitochondrial biogenesis, and mitochondrial network remodeling. Genipin activated autophagy in myoblasts and maintained cellular homeostasis. Autophagy inhibitors blocked the pro-differentiation effect of genipin. These results showed that genipin improved the differentiation efficiency of myoblasts, which provided a theoretical basis for the development of cultured meat technology.