Search Results (211)

The Janus Kinase (JAK) and Signal Transducers and Activators of Transcription (STAT) pathways regulate a range of biological processes, including immune response and hematopoiesis. While a major research focus has been on somatic human mutations in disease, less is known about the heritability of germline variants and their physiological impact. This study addresses an important issue in population genetics: the context-dependent effects and incomplete penetrance of rare genetic variants in immune pathways. Here we identify the rare JAK3^P151R, JAK3^R925S, STAT5A^V494L, and STAT6^Q633H variants in an extended family spanning three generations, integrate in silico analyses and AlphaFold 3 structural predictions, and investigate the immune transcriptomes in probands carrying one or more variants. All four variants are inherited through the germline without any evident clinical or physiological manifestations in the carriers. As individual variants, not all persons carrying a specific variant showed the same immune transcriptome. The presence of activated basal transcriptomes was limited to some, but not all, individuals carrying the above variants. A next step in understanding the role of germline variants will be to understand how and why other factors, including both other germline variants and environmental and developmental factors, influence the likelihood of expression of an activated basal transcriptome. Full article

Natural compounds, as honey-derived flavonoids and phenolic compounds, are increasingly investigated for their potential to mitigate skin aging and prevent oxidative stress-induced cellular damages. In this context, a dynamic cell culture model was employed to assess the protective influence of honey pre-treatment on stem cell–associated genes and the Wingless-related integration site (Wnt) signaling pathway following ultraviolet (UV)-induced aging. Using a bioreactor, skin stem cells (SSCs) derived from healthy skin biopsies and human skin fibroblasts (HFF1) were pre-treated with 1% honey for 48 h and then exposed to UV. Real-time quantitative polymerase chain reaction (RT-qPCR) analyses were performed on Wnt signaling and anti-aging molecular responses. Honey pre-treatment enhanced the expression of pluripotency markers (Octamer-binding transcription factor 4 (Oct4); SRY-box transcription factor 2 (Sox2)) and reduced senescence-related cell cycle regulators (cyclin-dependent kinase inhibitor 2A (p16); cyclin-dependent kinase inhibitor 1A (p21); tumor protein 53 (p53)) in SSCs. In UV-damaged SSCs, honey also significantly increased Wnt3a expression. In fibroblasts, honey pre-treatment upregulated Heat shock protein 70 (Hsp70) and Hyaluronan synthase 2 (HAS2) expression, while downregulating caspase-8 (CASP8), indicating a protective role against UV-mediated cellular stress. We also analyzed nitric oxide release and the total antioxidant capacity of cells after treatment. Collectively, these findings suggest that honey may safeguard skin stem cells from UV-induced aging by modulating pluripotency and senescence-associated genes and regulating differentiation through alterations in Wnt signaling. Furthermore, Hsp70 upregulation in fibroblasts appears to strengthen cellular stress responses and support homeostatic stability. Full article

Obesity is among the top contributing factors for non-communicable chronic disease development and has attained menacing global proportions, affecting approximately one of eight adults. Phytochemicals that support energy metabolism and prevent obesity development have been the subject of intense research endeavors over the past several decades. Cycloastragenol is a natural triterpenoid compound and aglycon of astragaloside IV, known for activating telomerase and mitigating cellular aging. Here, we aim to characterize the effect of cycloastragenol on lipid metabolism in a glucose-induced obesity model in Caenorhabditis elegans. We assessed the changes in the body length, width, and area in C. elegans maintained under elevated glucose through automated WormLab system. Lipid accumulation in the presence of either cycloastragenol (100 μM) or orlistat (12 μM), used as a positive anti-obesity control drug, was quantified through Nile Red fluorescent staining. Furthermore, we evaluated the changes in key energy metabolism molecular players in GFP-reporter transgenic strains. Our results revealed that cycloastragenol treatment decreased mean body area and reduced lipid accumulation in the C. elegans glucose-induced model. The mechanistic data indicated that cycloastragenol suppresses the nuclear hormone receptor family member NHR-49 and the delta(9)-fatty-acid desaturase 7 (FAT-7) enzyme, and activates the 5′-AMP-activated protein kinase catalytic subunit alpha-2 (AAK-2) and the protein skinhead 1 (SKN-1) signaling. Collectively, our findings highlight that cycloastragenol reprograms lipid metabolism by down-regulating the insulin-like receptor (daf-2)/phosphatidylinositol 3-kinase (age-1)/NHR-49 signaling while simultaneously enhancing the activity of the AAK-2/NAD-dependent protein deacetylase (SIR-2.1) pathway. The anti-obesogenic potential of cycloastragenol rationalizes further validation in the context of metabolic diseases and obesity management. Full article

Brown adipose tissue (BAT) and beige adipocytes play a crucial role in adaptive thermogenesis, primarily via uncoupling protein 1 (UCP1)-driven heat production. Once considered physiologically irrelevant in adults, BAT is now recognized as an active tissue that contributes to energy expenditure and metabolic homeostasis and represents a potential therapeutic target for obesity and metabolic disorders. This review provides an integrated overview of the molecular regulation of thermogenic adipocytes, emphasizing both canonical UCP1-dependent as well as non-canonical UCP1-independent mechanisms of heat generation. Key transcriptional and epigenetic regulators are discussed in the context of mitochondrial biogenesis, substrate utilization, and thermogenic gene programs. Major upstream signaling routes are further summarized, encompassing classical β-adrenergic pathways, as well as alternative regulatory nodes including AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) together with diverse nutrient- and hormone-responsive cues that converge to activate brown and beige adipocytes. Finally, the cross-talk among neuronal, endocrine, immune, and gut microbiota-derived signals is highlighted as a key determinant of thermogenic adipocyte function. Together, these multilayered regulatory inputs provide a comprehensive framework for understanding how thermogenic adipose tissue integrates environmental, metabolic, and microbial cues to regulate systemic energy balance—knowledge that is essential for developing targeted therapies to combat obesity and metabolic diseases. Full article

Melanin produced in melanocytes contributes to photoprotection, oxidative stress reduction, immune regulation, and epidermal homeostasis, while its dysregulation underlies diverse pigmentary disorders. Natural products modulate melanogenesis by regulating tyrosinase activity, intracellular signaling pathways such as extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) and cyclicAMP/protein kinase A/cAMP response element-binding protein (cAMP/PKA/CREB), and cellular redox balance. Anti-melanogenic effects have been reported for various fruit-derived phytochemicals, ginseng-based metabolites, and plant polyphenols, which act through direct enzymatic inhibition, suppression of melanoenic signaling, modulation of melanosome dynamics, and antioxidant or anti-inflammatory activities. Advances in delivery systems, including nano- and microencapsulation platforms, further enhance the stability and topical bioavailability of these compounds. In contrast, certain methoxylated flavonoids and phenolic constituents can stimulate pigmentation by sustaining melanogenic signaling and promoting microphthalmia-associated transcription factor (MITF)-driven transcription, emphasizing the context-dependent and bidirectional influence of natural substances on pigmentation outcomes. Collectively, these findings highlight the therapeutic potential of natural product-based modulators of melanogenesis while underscoring the need for mechanistic clarification, safety evaluation, and translational studies to ensure effective and controlled pigmentation management. This review summarizes the biological functions of melanin and examines natural strategies for regulating pigmentation. Full article

The insulin-like growth factor (IGF) axis orchestrates hepatic development, regeneration, and metabolism, yet the roles of individual IGF-binding proteins (IGFBPs) remain incompletely defined. IGFBP-6, a high-affinity, IGF-II-preferring binding protein, has emerged as a context-dependent modulator of IGF bioavailability and cell signaling with additional IGF-independent actions. This review synthesizes current evidence on IGFBP-6 in liver biology and disease. We first outline hepatic expression, regulation, and post-translational processing of IGFBP-6 across development, homeostasis, and injury, and summarize its effects on canonical IGF-II/IGF1R signaling and downstream phosphatidylinositol 3-kinase—protein kinase B (PI3K–AKT) and rat sarcoma—mitogen-activated protein kinase (RAS–MAPK) pathways. We then evaluate experimental and clinical data linking IGFBP-6 to steatotic liver disease, inflammation, and fibrogenesis, including putative roles in hepatocyte stress responses, stellate cell activation, and extracellular matrix remodeling. Finally, we examine IGFBP-6 in primary liver cancers—hepatocellular carcinoma and cholangiocarcinoma—highlighting evidence for tumor-suppressive versus pro-migratory activities, potential crosstalk with hypoxia, Wnt/β-catenin and TGF-β signaling, and interactions with the tumor immune microenvironment. Across conditions, we assess the translational potential of IGFBP-6 as a circulating or tissue biomarker, its utility for patient stratification, and prospects for therapeutic targeting—either by modulating IGF-II sequestration or exploiting IGF-independent mechanisms. We conclude by identifying key knowledge gaps, methodological limitations, and priorities for future studies, including standardized measurement, cell-type-resolved profiling, and in vivo perturbation in clinically relevant models. Collectively, the review positions IGFBP-6 as a nuanced regulator of liver pathophysiology and a promising, yet underexplored, lever for diagnosis and therapy. Full article

The mitogen-activated protein kinase (MAPK) signaling cascade is fundamental in regulating cellular proliferation and differentiation, cell survival and cell death via apoptosis. Disruption of the MAPK signaling cascade at any point can lead to the evasion of apoptosis and unchecked cell growth and proliferation, leading to oncogenesis. This narrative review describes MAPK pathway dysregulation, its therapeutic targets, and resistance mechanisms. The therapeutic targeting of the MAPK pathway is complex due to the dual context-dependent roles of several kinases in the signaling cascade. Despite the therapeutic effectiveness of MAPK inhibitors, cancer cells develop chemoresistance that needs to be targeted via bypassing (c-Jun N-terminal kinases) JNK, protein kinase AKT and (mammalian target of rapamycin) mTOR signaling cascades, pairing MAPK inhibitors with multiple immune agents and targeting the MAPK pathway downstream of (extracellular signal-regulated kinase) ERK to prevent its reactivation mechanisms using combination therapies, downstream signaling regulators and (Proteolysis Targeting Chimeras) PROTACs. Additionally, MAPK-mediated regulation of ferroptosis is a novel oncological therapeutic targeting strategy for controlling tumor progression. The inhibition of the RAF/MAPK pathway results in alteration of several key regulators of ferroptosis, including SLCA11, GSH, GPX4 and NCO4A, hence affecting lipid cellular iron concentration and lipid peroxidation. Emerging therapies targeting the MAPK pathway should be designed considering crosstalk, compensatory signaling mechanism activation, the role of ferroptosis and the impact of the tumor microenvironment. Full article

Vascular dysfunction lies at the core of cardiovascular diseases—the leading cause of global morbidity and mortality. Despite their prevalence, therapeutic options remain limited, in part due to an incomplete understanding of the molecular mechanisms driving vascular pathology. The integrated stress response (ISR), an evolutionarily conserved signaling network activated by diverse stressors, represents a critical but underexplored mechanism in vascular biology. This review examines the dual roles of the core ISR kinases—PERK, GCN2, HRI and PKR—in vascular homeostasis and pathology, including atherosclerosis, pulmonary hypertension, and angiogenesis. We develop a conceptual framework in which the ISR functions as a context-dependent, double-edged sword: while PERK and PKR promote inflammation, apoptosis, and vascular re-modeling, GCN2 mediates protective effects. The outcome of ISR activation is shaped by cell type, stress duration and intensity, and downstream signaling bias (e.g., ATF4 vs. CHOP dominance). We further discuss pharmacological ISR modulators—including 2-aminopurine, C16, salubrinal, halofuginone, GSK2606414, and GSK2656157—which have demonstrated beneficial effects in preclinical models by suppressing inflammation, reducing apoptosis, and attenuating disease progression. Collectively, the ISR emerges as a critical regulatory node in vascular pathophysiology, and its selective, context-aware modulation represents a promising avenue for therapeutic intervention. Full article

Background/Objectives: Targeting the PI3K/mTOR pathway is a promising strategy in cancer therapy, but its efficacy is often limited by apoptosis resistance. This study investigates the dual PI3K/mTOR inhibitor YYN-37, exploring its capacity to induce context-dependent cell death, particularly the non-apoptotic process of methuosis. Methods: We examined the effects of YYN-37 on HCT-116 and SJSA-1 cancer cell lines using cell viability assays, Western blot, and fluorescent tracers. Cell death mechanisms were probed with pathway-specific inhibitors. The role of VPS34 was assessed through kinase activity assays, siRNA-mediated knockdown, and rescue experiments with the agonist leucine. Proteomic profiling and an in vivo SJSA-1 xenograft model in BALB/c nude mice were utilized to evaluate broader mechanisms and anti-tumor efficacy. Results: YYN-37 induced caspase-3-dependent apoptosis in HCT-116 cells. In contrast, it triggered a reversible, cytoplasmic vacuolization in SJSA-1 cells, identified as methuosis. This vacuolization originated from endocytic pathways and was inhibited by EIPA and Baf-A1. YYN-37 directly inhibited VPS34 (IC₅₀ = 2.73 nM), and its knockdown replicated the vacuolization, which was conversely reversed by the VPS34 agonist leucine, confirming VPS34-dependency. Proteomics revealed lysosomal dysfunction in SJSA-1 cells and cell cycle alterations in HCT-116 cells. In vivo, YYN-37 treatment resulted in a 72.71% tumor growth inhibition, with histology confirming methuosis-like vacuolization. Conclusions: YYN-37 exerts potent, context-dependent anti-tumor effects by inducing apoptosis in HCT-116 cells and VPS34-mediated methuosis in SJSA-1 cells. This work establishes methuosis induction as a viable therapeutic strategy for apoptosis-resistant cancers and highlights VPS34 inhibition as a promising mechanism of action. Full article

Alternative splicing is a key regulator of immune regulation by enabling rapid and context-specific responses. However, the role of splicing regulators such as CDC-like kinase 1 (CLK1) in monocyte biology remains poorly defined. Here, we identify and characterize distinct CLK1-splice isoforms in human CD14⁺ monocytes using long-read RNA sequencing. In resting monocytes, we observe predominant expression of a truncated isoform lacking exon 4 (CLK1Δ4), which undergoes nonsense-mediated decay resulting in minimal protein output. Lipopolysaccharide (LPS) stimulation induces a shift toward the full-length isoform (CLK1+4), associated with increased transcript stability and protein expression. This splicing switch was confirmed by RT-qPCR, short-read RNA sequencing, and Western blot analysis. Pharmacological inhibition of CLK1 selectively reduced TNFα production without affecting cell viability, implicating that the isoform shift enhances pro-inflammatory signaling. These findings uncover a stimulus-dependent splicing mechanism that modulates monocyte activation through differential CLK1 isoform expression and suggest a potential therapeutic avenue by targeting splicing regulators in immune-related disease with an established role of activated monocytes. Full article

Ibrutinib (IB), a Bruton’s tyrosine kinase (BTK) inhibitor, is widely used against B-cell malignancies. However, its adverse effects on stem cell-dependent processes and tissue homeostasis remain incompletely understood. Freshwater planarians possess pluripotent stem cells (neoblasts), which enable remarkable regeneration of various tissues, including the central nervous system. This makes them ideal in vivo models for studying chemical toxicity within a whole-organism context. Here, we utilized planarian Dugesia constrictiva to assess IB toxicity and elucidate its mechanisms, focusing on its impact on stem cell dynamics and regeneration. Our results demonstrated that exposure to IB at concentrations as low as 0.9 mg/L, far below clinical plasma levels, led to severe morphological and regenerative impairments, including disrupted neural regeneration. Mechanistically, IB disrupted stem cell dynamics by suppressing proliferation and differentiation and by inducing oxidative stress via ROS overproduction. Notably, IB exposure significantly downregulated BTK expression. Crucially, BTK RNAi caused the key toxic effects of IB exposure, including morphological and regenerative defects, suppression of stem cell proliferation and differentiation, and increased apoptosis. Therefore, we conclude that IB may exert its toxicity in planarians primarily through BTK inhibition. This finding provides direct functional evidence linking BTK inhibition to stem cell dysfunction and regenerative defects in a novel in vivo context, offering critical insights for refining the clinical safety profile of IB. Full article

MicroRNA-221 (miR-221), a conserved small non-coding RNA, acts as a pivotal modulator of biological processes across multiple organ systems, the dysregulation of which is closely linked to the pathogenesis of various human diseases. This review systematically summarizes its multifaceted roles in cancer, cardiovascular diseases (CVDs), neurological disorders, digestive system diseases, respiratory conditions, and adipose-endocrine dysfunction. In cancer, miR-221 exerts context-dependent oncogenic/tumor-suppressive effects by targeting phosphatase and tensin homolog (PTEN), cyclin-dependent kinase inhibitor 1c (CDKN1C/p57), and BCL2 modifying factor (Bmf), thereby regulating cell proliferation, invasion, stemness, and resistance to cancer therapy; it also serves as a non-invasive biomarker for glioma, papillary thyroid carcinoma, and colorectal cancer. In the cardiovascular system, it balances antiviral defense in viral myocarditis, modulates ventricular fibrotic remodeling in heart failure, and regulates endothelial function in atherosclerosis, with cell-type/ventricle-specific effects. In neurological disorders, it protects dopaminergic neurons in Parkinson’s disease and modulates microglial activation in epilepsy. It also regulates hepatic pathogen defense and intestinal mucosal immunity. Mechanistically, miR-221 alters cellular phenotypes by targeting tumor suppressors or signaling components (e.g., PI3K/AKT, TGF-β/suppressor of mothers against decapentaplegic homolog(SMAD), Wnt/β-catenin). Therapeutically, miR-221-targeting strategies show preclinical promise in cancer and CVDs. Despite this progress, further studies are needed to resolve context-dependent functional discrepancies, validate biomarker utility, and develop cell-specific delivery systems. This review provides a framework to understand its pathophysiologcial roles and potential application as a biomarker and therapeutic target. Full article

Cyclin-dependent kinase 5 (Cdk5) is an atypical serine/threonine kinase distinct from classical cell cycle regulators. Its activity is highest in the nervous system and essential for development, but its functions in other tissues, particularly in cancer, are increasingly being elucidated. This review explores the functional duality of Cdk5 by comparing its constructive role in neurodevelopment with its repurposed oncogenic function in cancer. In neurodevelopment, Cdk5 orchestrates nearly every stage of brain construction, including neuronal differentiation, migration, and synaptic plasticity. However, in many cancers, this neurodevelopmental toolkit is repurposed, and aberrantly activated Cdk5 promotes proliferation, metastasis, and therapeutic resistance in diverse solid tumors. Cdk5 also actively shapes the tumor microenvironment by promoting angiogenesis and modulating immunity. Notably, this oncogenic function is not universal, as Cdk5 exhibits its duality even within the context of cancer; it acts as a tumor suppressor in gastric cancer upon nuclear localization. Taken together, these lines of evidence underscore that Cdk5 is a context-dependent kinase whose output is determined by upstream regulation, subcellular localization, and the cellular environment. This review discusses the molecular basis of its dual role and highlights both the potential and complexity of Cdk5 as a therapeutic target in oncology. Full article

Background/Objectives: Protein kinase C-δ (PKC-δ) is a pivotal regulator of cellular signalling, and its dysregulation contributes to oncogenesis. While certain isolated PKC-δ domains have been crystallised, the full-length architecture and interdomain interactions remain largely unresolved, limiting mechanistic insight and the design of selective modulators. We aimed to define the full-length, inactive conformation of PKC-δ and identify accessible, functionally relevant binding sites for ligand discovery. Methods: We generated a consensus structural model of full-length inactive PKC-δ using multi-template comparative modelling guided by established inactivity markers. Molecular docking was used to predict ligands targeting the C2 domain, which were subsequently validated in breast cancer cell models, including wild-type and C2 domain-overexpressing lines. Results: Analysis of the model revealed the architecture of the C2/V5 interdomain space, providing a structural rationale for regulation of the nuclear localisation signal (NLS). Docking identified two ligand classes: ligand 1 engaged a C2 domain surface oriented toward the C2/V5 pocket, while ligand 2 targeted the C2 domain phosphotyrosine-binding domain (PTD). Experimental validation in breast cancer cell models demonstrated that both ligands reduced cell viability; ligand 1 showed enhanced effects in C2-overexpressing cells, consistent with predicted accessibility, whereas ligand 2 partially counteracted the C2 domain-induced viability phenotype, likely via interference with PTD-mediated interactions. Conclusions: Full-length structural context is essential for identifying accessible, functionally relevant binding sites and understanding context-dependent kinase regulation. Integrating computational modelling with phenotypic validation establishes a framework for selective PKC-δ modulation, offering insights to guide ligand discovery, improve isoform selectivity, and inform strategies to mitigate kinase inhibitor resistance in precision oncology. Full article

Calcium/calmodulin-dependent protein kinase II (CaMKII) comprises multiple isoforms with distinct nuclear variants that exert transcriptional control in a context-dependent manner. Among them, CaMKIIδB and δ9 in the heart, and CaMKIIγ in the nervous system, have emerged as regulators of chromatin dynamics, transcription factor activity, and developmental gene programs. Nuclear localization is driven by splice-dependent nuclear localization sequences, with phosphorylation at defined serine residues modulating import and retention. Evidence supports CaMKII-dependent phosphorylation of class IIa HDACs (Ser467/Ser632 in HDAC4), linking CaMKII to MEF2 activation in cardiac hypertrophy, and interactions with NF-κB and HSF1 further expand its nuclear repertoire. In the nervous system, CaMKIIγ contributes to kinase-dependent gene expression, potentially influencing plasticity and disease susceptibility. While these mechanisms highlight nuclear CaMKII as an isoform-specific regulator of transcription, direct evidence remains elusive, and several CaMKII putative substrates require further validation. This review synthesizes current knowledge on nuclear CaMKII isoforms, emphasizes established mechanistic pathways, and outlines unsolved questions critical for understanding their roles in development, disease progression, and therapeutic targeting. Full article