Search Results (977)

Macrophages are undoubtedly one of the most widely studied cells of the immune system, among other reasons, because they are involved in a wide variety of biological processes. Deregulation of their activity is observed in a number of different disorders, including autoimmune diseases. At the same time, mammalian target of rapamycin (mTOR) is attracting increasing research attention because the pathways dependent on this kinase are activated by a variety of signals, including cytokines and proinflammatory mediators, mediate essential processes for cell survival and metabolism, and can be regulated epigenetically via microRNAs. Therefore, our narrative review aimed to summarize and discuss recent advances in the knowledge of the activation of mTOR signaling in macrophages, with a special focus on autoimmune disorders and the possibility of mTOR control by microRNAs. The summarized research observations allowed us to conclude that the effects of activity and/or inhibition of individual mTOR complexes in macrophages are largely context dependent, and therefore, these broad immunological contexts and other specific conditions should always be taken into account when attempting to modulate these pathways for therapeutic purposes. Full article

Miller–Dieker Syndrome (MDS) is a rare neurodevelopmental disorder caused by a heterozygous deletion of approximately 26 genes within the MDS locus of human chromosome 17. MDS, which affects 1 in 100,000 babies, can lead to a range of phenotypes, including lissencephaly, severe neurological defects, distinctive facial abnormalities, cognitive impairments, seizures, growth retardation, and congenital heart and liver abnormalities. One hallmark feature of MDS is an unusually smooth brain surface due to abnormal neuronal migration during early brain development. Several genes located within the MDS locus have been implicated in the pathogenesis of MDS, including PAFAH1B1, YWHAE, CRK, and METTL16. These genes play a role in the molecular and cellular pathways that are vital for neuronal migration, the proper development of the cerebral cortex, and protein translation in MDS. Improved model systems, such as MDS patient-derived organoids and multi-omics analyses indicate that WNT/β-catenin signaling, calcium signaling, S-adenosyl methionine (SAM) homeostasis, mammalian target of rapamycin (mTOR) signaling, Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling, and others are dysfunctional in MDS. This review of MDS integrates details at the clinical level alongside newly emerging details at the molecular and cellular levels, which may inform the development of novel therapeutic strategies for MDS. Full article

Microglia, as the immune guardians of the central nervous system (CNS), have the ability to maintain neural homeostasis, respond to environmental changes, and remodel the synaptic landscape. However, persistent microglial activation can lead to chronic neuroinflammation, which can alter neuronal signaling pathways, resulting in accelerated cognitive decline. Phosphoinositol 3-kinase (PI3K) has emerged as a critical driver, connecting inflammation to neurodegeneration, serving as the nexus of numerous intracellular processes that govern microglial activation. This review focuses on the relationship between PI3K signaling and microglial activation, which might lead to cognitive impairment, inflammation, or even neurodegeneration. The review delves into the components of the PI3K signaling cascade, isoforms, and receptors of PI3K, as well as the downstream effects of PI3K signaling, including its effectors such as protein kinase B (Akt) and mammalian target of rapamycin (mTOR) and the negative regulator phosphatase and tensin homolog (PTEN). Experiments have shown that the overproduction of certain cytokines, coupled with abnormal oxidative stress, is a consequence of poor PI3K regulation, resulting in excessive synapse pruning and, consequently, impacting learning and memory functions. The review also highlights the implications of autonomously activated microglia exhibiting M1/M2 polarization driven by PI3K on hippocampal, cortical, and subcortical circuits. Conclusions from behavioral studies, electrophysiology, and neuroimaging linking cognitive performance and PI3K activity were evaluated, along with new approaches to therapy using selective inhibitors or gene editing. The review concludes by highlighting important knowledge gaps, including the specific effects of different isoforms, the risks associated with long-term pathway modulation, and the limitations of translational potential, underscoring the crucial role of PI3K in mitigating cognitive impairment driven by neuroinflammation. Full article

Sarcopenia, the progressive loss of muscle mass, strength, and regenerative capacity with age, is driven by interconnected processes such as oxidative stress, chronic inflammation, mitochondrial dysfunction, and reduced activity of muscle stem cells. As the population ages, nutritional strategies that target these mechanisms are becoming increasingly important. This review focuses on nicotinamide (vitamin B3) and pyridoxine (vitamin B6), two essential micronutrients found in functional foods, which play complementary roles in redox regulation, immune balance, and muscle repair. Nicotinamide supports nicotinamide adenine dinucleotide (NAD⁺) metabolism, boosts mitochondrial function, and activates sirtuin pathways involved in autophagy and stem cell maintenance. Pyridoxine, via its active form pyridoxal 5′-phosphate (PLP), is key to amino acid metabolism, antioxidant defense, and the regulation of inflammatory cytokines. We summarize how these vitamins influence major molecular pathways such as Sirtuin1 (SIRT1), protein kinase B (AKT)/mechanistic target of rapamycin (mTOR), Nuclear factor-κB (NF-κB), and Nrf2, contributing to improved myogenic differentiation and protection of the aging muscle environment. We also highlight emerging preclinical and clinical data, including studies suggesting possible synergy between B3 and B6. Finally, we discuss how biomarkers such as PLP, nicotinamide mononucleotide (NMN), and C-reactive protein (CRP) may support the development of personalized nutrition strategies using these vitamins. Safe, accessible, and mechanistically grounded, nicotinamide and pyridoxine offer promising tools for sarcopenia prevention and healthy aging. Full article

Tempol is a synthetic antioxidant that shows promise in preclinical cancer studies by inhibiting growth and inducing apoptosis. Given that the Mitogen-Activated Protein Kinase (MAPK) and Protein Kinase B/Mammalian Target of Rapamycin (Akt/mTOR) signaling pathways are frequently dysregulated in gastric and colon cancers and contribute to their progression, we investigated Tempol’s anti-cancer potential in HT29 (colon) and CRL-1739 (gastric) cancer cells. Cells were treated with 2 mM Tempol for 48 h, with untreated cells as controls. We evaluated apoptosis (Bax, cleaved caspase-3, and Bcl-2), key signaling pathway activity (p-ERK, p-JNK, p-AKT, and p-mTOR), and levels of stress- and apoptosis-related proteins (WEE1, GADD153, GRP78, and AIF). Tempol significantly increased pro-apoptotic Bax and cleaved caspase-3 (p < 0.0001) and decreased anti-apoptotic Bcl-2 (p < 0.0001) in both cell lines. Furthermore, Tempol markedly reduced the activity of p-ERK, p-JNK, p-AKT, and p-mTOR (p < 0.0001) and significantly increased the protein levels of WEE1, GADD153, GRP78, and AIF (p < 0.0001). Tempol treatment also led to a significant increase in total oxidant status and a decrease in total antioxidant status. In conclusion, our findings suggest that Tempol exhibits its anti-cancer activity through multiple interconnected mechanisms, primarily inducing apoptosis and oxidative stress, while concurrently suppressing pro-survival signaling pathways. These results highlight Tempol’s potential as a therapeutic agent for gastric and colon cancers. Full article

Despite the successes achieved in recent years in the treatment of childhood acute lymphoblastic leukemia (ALL), high-risk ALL in particular still represents a considerable challenge, with poorer outcomes. The PI3K/AKT/mTOR signaling pathway is frequently constitutively activated in ALL and consequently leads to unrestricted cell proliferation, without showing frequent mutations in the most important representatives of the signaling pathway. Recent studies have shown that fine balanced protein expression is a common way to adjust oncogenic B cell directed receptor signaling and to mediate malignant cell proliferation and survival in leukemic cells. Too low expression of inhibitory phosphatases can lead to constitutive signaling of kinases, which are important for cell proliferation and survival. In contrast, marked high expression levels of key phosphatases enable cells with distinct pronounced oncogenic B cell directed receptor signaling to escape negative selection by attenuating signal strength and thus raising the threshold for deletion checkpoint activation. One of the most important B cell receptor-dependent signaling cascades is the PI3K/AKT signaling pathway, with its important antagonist SHIP1. However, recent data show that the inositol-5-phosphatase SHIP1 is differentially expressed across the heterogeneity of the ALL subtypes, making the overall therapeutic strategy targeting SHIP1 more complex. The aim of this article is therefore to provide an overview of the current knowledge about SHIP1, its expression in the various subtypes of ALL, its regulation, and the molecules that influence its gene and protein expression, to better understand its role in the pathogenesis of leukemia and other human cancers. Full article

Inflammation is a self-defense mechanism that controls the homeostasis of an organism, and its alteration by persistent noxious stimuli could lead to an imbalance in the regulation of inflammatory responses mediated by innate and adaptive immunity. During chronic inflammation, sustained exposure of myeloid cells to the various inflammatory signals derived from inflamed tissue could lead to the generation of myeloid cells with an immunosuppressive state, called myeloid-derived suppressor cells (MDSCs), which can exert protective or deleterious functions depending on the nature of signals and the specific inflammatory conditions created by different pathophysiological contexts. Initially identified in various tumor models and cancer patient samples, these cells have long been recognized as negative regulators of anti-tumor immunity. Consequently, researchers have focused on elucidating the molecular mechanisms underlying their potent immunosuppressive activity. As a key component of the signal transducing processes, protein kinases play a central role in regulating the signal transduction mechanisms of many cellular activities, including differentiation and immunosuppression. Over the past decade, at least a dozen kinases, including mechanistic target of rapamycin (mTOR), phosphoinositide 3-kinases (PI3Ks), TAM (Tyro3, Axl, Mer) family of receptor tyrosine kinases (TAM RTKs), mitogen-activated protein kinases (MAPKs), and others, have emerged as key contributors to the generation and differentiation of MDSCs. Here, we discuss the recent findings on these kinases that directly contribute to the immunosuppressive functions of MDSCs. Full article

Diabetic foot ulcers (DFUs), which affect approximately 15% of individuals with diabetes mellitus (DM), result from complex molecular disturbances involving chronic hyperglycemia, immune dysfunction, and infection. At the molecular level, chronic hyperglycemia promotes the formation of advanced glycation end products (AGEs), activates the AGE-RAGE-NF-κB axis, increases oxidative stress, and impairs macrophage polarization from the pro-inflammatory M1 to the reparative M2 phenotype, collectively disrupting normal wound healing processes. The local wound environment is further worsened by antibiotic-resistant polymicrobial infections, which sustain inflammatory signaling and promote extracellular matrix degradation. The rising threat of antimicrobial resistance complicates infection management even further. Recent studies emphasize that optimal glycemic control using antihyperglycemic agents such as metformin, Glucagon-like Peptide 1 receptor agonists (GLP-1 receptor agonists), and Dipeptidyl Peptidase 4 enzyme inhibitors (DPP-4 inhibitors) improves overall metabolic balance. These agents also influence angiogenesis, inflammation, and tissue regeneration through pathways including AMP-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR), and vascular endothelial growth factor (VEGF) signaling. Evidence indicates that maintaining glycemic stability through continuous glucose monitoring (CGM) and adherence to antihyperglycemic treatment enhances antibiotic effectiveness by improving immune cell function and reducing bacterial virulence. This review consolidates current molecular evidence on the combined effects of glycemic and antibiotic therapies in DFUs. It advocates for an integrated approach that addresses both metabolic and microbial factors to restore wound homeostasis and minimize the risk of severe outcomes such as amputation. Full article

Background/Objectives: The integration of natural compounds in cancer research marked a crucial shift in the modern medical landscape, through a growing acknowledgment of their potential as efficient, less toxic, and cost-effective alternatives to contemporary chemotherapeutics. Liquiritigenin (LIQ) is a compound obtained from different plants, the most important being the Glycyrrhiza species, commonly known as licorice. Methods: This review compiles findings from previously published preclinical studies and experimental research articles focusing on LIQ’s pharmacological effects, with particular attention to its anticancer potential. The relevant literature was identified using established scientific databases and selected based on relevance to cancer biology and LIQ-associated signaling pathways. Results: LIQ demonstrates anti-oxidant, anti-inflammatory, and anti-proliferative effects. It exerts its potential anticancer activities by inducing apoptosis, preventing cell proliferation, and modulating various signaling pathways such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositide 3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (MAPK), and so on. Conclusions: LIQ represents a promising natural agent for cancer therapy, with evidence supporting its multifunctional role in targeting tumor growth and survival mechanisms. By providing a detailed analysis of LIQ, this review aims to highlight its therapeutic efficacy across various cancer types and emphasize its importance as a promising compound in cancer research. In addition, this review seeks to bridge the gap between traditional medicine and modern pharmacology and paves the way for LIQ’s clinical application in cancer therapy. Full article

Non-alcoholic fatty liver disease (NAFLD) is a common metabolic condition characterized by hepatic lipid deposits, insulin resistance, and inflammation which may progress to non-alcoholic steatohepatitis (NASH) and fibrosis. Protein kinases play an important role in NAFLD development by regulating metabolic and inflammatory pathways. Mitogen-activated protein kinases (MAPKs), protein kinase C (PKC), AMP-activated protein kinase (AMPK), phosphoinositide 3-kinase (PI3K)/AKT, and mechanistic target of rapamycin (mTOR) are all involved in NAFLD and NASH progression. Emerging evidence indicates that Farnesoid X Receptor (FXR) agonists have therapeutic potential by modulating bile acid metabolism, lipid balance, and inflammatory responses. This review examines the mechanistic interplay between FXR agonists and important protein kinases in NAFLD and NASH. FXR agonists activate AMPK, which promotes fatty acid oxidation and reduces hepatic steatosis. They also regulate MAPK signaling, which reduces c-Jun NH2-terminal kinase (JNK)- and p38 MAPK-mediated inflammation. Furthermore, FXR agonists activate the PI3K/AKT pathway, enhancing insulin sensitivity and modulating mTOR signaling to reduce hepatic fibrosis. Clinical studies in NAFLD/NASH indicate that FXR agonists confer metabolic and anti-inflammatory benefits, although optimizing efficacy and minimizing adverse effects remain challenging. Future studies should focus on combination therapies targeting FXR alongside specific kinases to improve therapeutic outcomes. This review highlights the potential of FXR agonists to modulate protein kinase signaling, opening new avenues for targeted NAFLD/NASH therapy. Full article

As life expectancy increases, muscle atrophy, characterized by a decline in muscle mass and strength that can impair mobility, has become a growing concern, highlighting the potential of protein supplementation as a promising intervention strategy. A horse meat hydrolysate, with a molecular weight of less than 3 kDa, derived from m. biceps femoris and produced using the food-grade enzyme Alcalase^® (A4 < 3kDa) was evaluated for its efficacy in mitigating dexamethasone-induced muscle atrophy, a widely accepted model for studying catabolic muscle loss. Administered orally to C57BL/6 mice at dosages of 200 mg/kg or 500 mg/kg body weight for 35 days, A4 < 3kDa effectively countered the weight loss induced by dexamethasone in the whole body, quadriceps, tibialis anterior, and gastrocnemius muscles. Moreover, it increased muscle fiber cross-sectional area and grip strength. These effects were attributed to increased protein synthesis via the protein kinase B (AKT)/forkhead box O3 (FoxO3a)/mammalian target of rapamycin (mTOR) signaling pathway. A4 < 3kDa augmented the phosphorylation of key components of the signaling pathways associated with muscle atrophy, resulting in reduced mRNA expression of Atrogin-1 and MuRF-1. These findings demonstrate the potential of A4 < 3kDa as a functional food ingredient for preventing muscle atrophy. Full article

Alzheimer’s disease (AD) and schizophrenia are traditionally considered distinct clinical entities, yet growing evidence highlights substantial overlap in their molecular and neuroinflammatory pathogenesis. This review explores current insights into the shared and divergent mechanisms underlying these disorders, with emphasis on neuroinflammation, autophagy dysfunction, blood–brain barrier (BBB) disruption, and cognitive impairment. We examine key signaling pathways, particularly spleen tyrosine kinase (SYK), the mechanistic (or mammalian) target of rapamycin (mTOR), and the S100 calcium-binding protein B (S100B)/receptor for advanced glycation end-products (RAGE) axis, that link glial activation, excitatory/inhibitory neurotransmitter imbalances, and impaired proteostasis across both disorders. Specific biomarkers such as S100B, matrix metalloproteinase 9 (MMP9), and soluble RAGE show promise for stratifying disease subtypes and predicting treatment response. Moreover, psychiatric symptoms frequently precede cognitive decline in both AD and schizophrenia, suggesting that mood and behavioral disturbances may serve as early diagnostic indicators. The roles of autophagic failure, cellular senescence, and impaired glymphatic clearance are also explored as contributors to chronic inflammation and neurodegeneration. Current treatments, including cholinesterase inhibitors and antipsychotics, primarily offer symptomatic relief, while emerging therapeutic approaches target upstream molecular drivers, such as mTOR inhibition and RAGE antagonism. Finally, we discuss the future potential of personalized medicine guided by genetic, neuroimaging, and biomarker profiles to optimize diagnosis and treatment strategies in both AD and schizophrenia. A greater understanding of the pathophysiological convergence between these disorders may pave the way for cross-diagnostic interventions and improved clinical outcomes. Full article

Colorectal cancer remains a leading malignancy. As the aberrant activation of Wnt/β-catenin signaling causes colorectal cancer, Wnt/β-catenin signaling inhibitors are potential candidates for colorectal cancer treatment. Our drug screening platform identified ursolic acid (UA), a triterpenoid with various biological activities, as a potential anticancer drug because it inhibits the T-cell factor (TCF)/β-catenin-mediated transcriptional activity. Here, we discovered that UA inhibited Wnt signaling by reducing the Wnt reporter activity and Wnt target gene expression, leading to a delay in cell cycle progression and the suppression of cell proliferation. Stepwise epistatic analyses suggested that UA functions on β-catenin protein stability in Wnt signaling. Further studies revealed that UA reduced β-catenin protein levels by Western blotting and immunofluorescent staining and induced autophagy by microtubule-associated protein 1 light chain 3 beta (LC3B) punctate staining. The cotreatment with UA and the autophagy inhibitors chloroquine and wortmannin recovered the β-catenin protein levels. Therefore, UA was confirmed to induce β-catenin degradation by the autophagy–lysosomal degradation system through inhibition in the phosphatidylinositol 3-kinase (PI3K)/Ak strain transforming (protein kinase B; AKT)/mammalian target of rapamycin (mTOR) signaling pathway. Our results not only highlight the potential of UA in Wnt-driven colorectal cancer therapy but also provide a workable Wnt signaling termination approach for the treatment of other Wnt-related diseases. Full article

Glycine has the greatest rate of deposition in whole-body proteins among all amino acids in neonates, but its provision from sow’s milk meets only 20% of the requirement of suckling piglets. The results of our recent studies indicate that piglets with intrauterine growth restriction (IUGR) have a reduced ability to synthesize glycine. The present study determined the role of glycine in the growth of sow-reared IUGR piglets. In Experiment 1, 56 newborn piglets (postnatal day 0) with a low birth weight (<1.10 kg) were selected from 14 litters, providing 4 IUGR piglets/litter that were allotted randomly into one of four treatment groups (14 piglets/group). Piglets received oral administration of either 0, 0.1, 0.2 or 0.4 g glycine/kg body weight (BW) twice daily (i.e., 0, 0.2, 0.4 or 0.8 g glycine/kg BW/day) between 0 and 14 days of age. L-Alanine was used as the isonitrogenous control. The BWs of all piglets were recorded each week during the experiment. Two weeks after the initiation of glycine supplementation, blood and tissue samples were collected for biochemical analyses. In Experiment 2, rates of muscle protein synthesis in tissues were determined on day 14 using the ³H-phenylalanine flooding dose technique. Compared with piglets in the control group, oral administration of 0.2, 0.4 and 0.8 g glycine/kg BW/day did not affect their milk intake (p > 0.05) but increased (p < 0.05) concentrations of glycine in plasma by 1.52-, 1.94-, and 2.34-fold, respectively, and body weight by 20%, 37%, and 34%, respectively. The dose of 0.4 g glycine/kg BW/day was the most cost-effective. Consistent with its growth-promoting effect, glycine supplementation stimulated (p < 0.05) the phosphorylation of mechanistic target of rapamycin (MTOR), eukaryotic initiation factor 4E binding protein 1 (4E-BP1), and ribosomal protein S6 kinase beta-1 (p70^S6K) as well as protein synthesis in skeletal muscle, compared with the control group. Collectively, oral administration of glycine activated the MTOR signaling pathway in skeletal muscle and enhanced the growth performance of IUGR piglets. These results indicate that endogenous synthesis of glycine is inadequate to meet the needs of IUGR piglets during the suckling period and that oral supplementation with glycine to these compromized neonates can improve their growth performance. Full article

Aging is the greatest risk factor for Alzheimer’s disease (AD), but the mechanisms connecting the two remain unclear. The mammalian target of rapamycin (mTOR) pathway, particularly its downstream effector S6 kinase 1 (S6K1), has emerged as a key regulator of aging and neurodegeneration. S6K1 controls translation, autophagy, and mitochondrial function—processes disrupted in both aging and AD. This review examines how S6K1 influences mitochondrial metabolism, autophagy, and metabolic dysfunction in aging. We also discuss its role in the nervous system, including effects on synaptic plasticity, memory, glial activation, and neuroinflammation. In AD, S6K1 contributes to amyloid and tau pathology by regulating translation of BACE1 and tau, and its hyperactivation is linked to synaptic deficits and cognitive decline. We further explore therapeutic strategies targeting S6K1, which have shown benefits for lifespan extension and neuroprotection in preclinical models. Finally, we consider the emerging link between S6K1 and necroptosis, a form of programmed cell death implicated in AD-related neuronal loss. Together, these findings highlight S6K1 as a promising target for interventions aimed at slowing aging and mitigating AD pathogenesis. Full article