Search Results (7,172)

Chronic liver injury is characterized by sustained activation of transforming growth factor-β (TGF-β) signaling within the fibrotic microenvironment, yet the contribution of TGF-β-associated metabolic remodeling to hepatic stellate cell (HSC) activation remains incompletely understood. Here, we investigated whether TGF-β signaling is associated with lipid metabolic remodeling in HSCs and whether pirfenidone (PFD) interferes with this process. We found that TGF-β1 was spatially associated with lipid accumulation in fibrotic liver tissue and that TGF-β1/2 promoted HSC proliferation. In vitro, TGF-β1/2 coordinately upregulated sterol regulatory element-binding protein 1 (SREBP1) and fatty acid synthase (FASN), accompanied by increased intracellular lipid accumulation and enhanced oleic acid (OA)-associated lipid responses. Low-dose OA further activated AKT/ERK/p70 S6K signaling in HSCs, whereas PFD attenuated these signaling events. In parallel, PFD suppressed TGF-β-associated lipid accumulation in vitro, reduced SREBP1/FASN expression in activated HSC-rich regions in vivo, and alleviated CCl₄-induced liver fibrosis. Together, these findings support a model in which TGF-β-associated lipogenic remodeling contributes to HSC activation and suggest that interference with this metabolic state may represent one component of the antifibrotic action of pirfenidone. Full article

Chlamydia trachomatis has evolved sophisticated mechanisms to manipulate key host cell signaling pathways to facilitate its intracellular reproduction. N6-methyladenosine (m6A) in RNA is known to regulate various physiological and disease processes, and is also involved in the regulation of pathogenic and developmental processes in many pathogens. However, the specific impact of m6A modification on the intracellular growth of C. trachomatis remains poorly understood. In this study, our analysis of the m6A methylation profiles of host cell mRNAs following C. trachomatis infection revealed significant alterations in the distribution of m6A modifications, methylation motifs, and m6A-modified host target genes. We further demonstrate that chlamydial intracellular reproduction is mediated by the host methyltransferase-like (METTL) enzyme METTL14. Silencing METTL14 significantly reduced the reproduction efficiency of C. trachomatis. Mechanistically, C. trachomatis activates the Mitogen-Activated Protein Kinase (MAPK) and Phosphatidylinositol 3-kinase/Protein Kinase B (PI3K/AKT) signaling pathways through METTL14, thereby inhibiting host cell apoptosis and promoting intracellular bacterial reproduction. Collectively, these findings identify METTL14 as a key host factor for chlamydial intracellular reproduction, providing new mechanistic insights and potential targets for therapeutic intervention. Full article

Cadmium (Cd) is a pervasive environmental contaminant with potent cytotoxic effects in a wide range of organisms. Although autophagy and apoptosis are recognized as major cellular responses to heavy metal stress, the molecular basis of Cd-induced cell death in insects remains insufficiently understood. In this study, we used fifth-instar day-4 (5L4D) larvae of Bombyx mori and the silkworm-derived Bm-12 cell line to investigate the involvement of three core autophagy-related proteins, Bombyx mori Autophagy-related protein 5(BmATG5), Bombyx mori Autophagy-related protein 6(BmATG6), and Autophagy-related protein 8(BmATG8), in Cd-induced autophagy and apoptosis. Exposure to CdCl₂ markedly induced autophagic and apoptotic responses in both larval midgut tissue and Bm-12 cells, as demonstrated by monodansylcadaverine(MDC) staining, Lyso-Tracker Red staining, DAPI and Hoechst 33258 staining, and DNA fragmentation assays. qPCR and Western blot analyses showed significant upregulation of BmATG5, BmATG6, and BmATG8 following Cd exposure. Notably, the cleaved forms tBmATG5-N (24 kDa) and tBmATG6-C (35 and 37 kDa), as well as the lipidated form BmATG8-PE (12 kDa), accumulated substantially under Cd stress. In parallel, intracellular Ca²⁺ levels and calpain activity were significantly increased, suggesting activation of a calcium-dependent regulatory pathway. Pharmacological inhibition experiments further indicated that autophagy and apoptosis are functionally interconnected during the Cd response. Collectively, these findings demonstrate that BmATG5, BmATG6, and BmATG8, together with their processed forms, play central roles in coordinating autophagy–apoptosis crosstalk during Cd-induced cytotoxicity in Bombyx mori. This study provides new mechanistic insight into heavy metal toxicity in insects and expands our understanding of stress-induced programmed cell death during silkworm metamorphosis. Full article

Epigenetic mechanisms, including DNA methylation and hydroxymethylation, contribute to inflammation, cardiac remodelling and progression of heart failure. Ten–Eleven Translocation (TET) dioxygenases are key regulators of these processes, but the impact of statins on TET proteins in human heart failure is not well characterised. We investigated how statin therapy relates to TET1, TET2 and TET3 expression in circulating immune cells in heart failure with reduced ejection fraction (HFrEF). In this cross-sectional study, 106 patients with HFrEF were enrolled; 84 were receiving statins and 22 were not. Intracellular TET1/2/3 protein levels were measured by multiparameter flow cytometry in granulocytes, monocytes and lymphocytes, and clinical and laboratory characteristics were compared between groups. Statin-treated patients had lower NT-proBNP concentrations and lower neutrophil, lymphocyte and monocyte counts, and more often received guideline-directed medical therapy. Statin therapy was associated with a distinct TET expression profile, characterised by higher TET1 and TET3 indices in monocytes and lymphocytes and lower TET2 indices in granulocytes and monocytes. This pattern is compatible with a distinct immune-cell TET expression profile aligned with the anti-inflammatory and reparative profile attributed to statins, and the course of disease. These associations do not establish causality and require prospective validation. TET proteins may form part of an epigenetic signature associated with statin treatment in heart failure and warrant further study as potential biomarkers in larger, prospective cohorts. Full article

Latrophilin 1 (LPHN1/ADGRL1), an adhesion G-protein-coupled receptor (GPCR), is the principal receptor for α-latrotoxin (αLTX), a toxin that triggers massive neurotransmitter release. However, its endogenous signaling mechanism remains elusive. Here, we dissect the LPHN1 signaling pathway at the vertebrate neuromuscular junction, using the pore-deficient αLTX mutant LTX^N4C as a selective agonist. Combining electrophysiological recordings from LPHN1 knockout mice with pharmacological inhibitors, calcium imaging, and biochemical assays, we delineate the cascade from receptor activation to spontaneous quantal acetylcholine release. We demonstrate that LPHN1 is specifically localized to the presynaptic membrane and mediates LTX^N4C-evoked release. Upon activation, LPHN1 engages the G_αq–phospholipase C pathway to generate inositol 1,4,5-trisphosphate (IP₃), triggering Ca²⁺ release from intracellular stores via IP₃ receptors. This store depletion activates store-operated Ca²⁺ entry (SOCE), providing sustained Ca²⁺ required for LTX^N4C-induced burst-like exocytosis. We uncover distinct roles for Ca_V2.1 and Ca_V1 channels in initiating and sustaining this response. These findings establish LPHN1 as a GPCR that harnesses intracellular stores and SOCE to drive spontaneous neurotransmission, revealing a novel signaling paradigm for adhesion GPCRs in presynaptic function. Full article

Arachidonic acid (AA) is an emerging regulator of fibroblast activity in pulmonary fibrosis; however, the underlying intracellular mechanisms remain unclear. This study investigated the effects of AA on the free intracellular calcium concentration ([Ca²⁺]_i), nitric oxide (NO), and reactive oxygen species (ROS) in human WI-38 lung fibroblasts. Using fluorescent imaging and pharmacological tools, we demonstrate that AA evokes a robust, concentration-dependent increase in [Ca²⁺]_i. This response is initiated by G protein-coupled receptor 40 (GPR40), which leads to endoplasmic reticulum Ca²⁺ release through inositol 1,4,5-trisphosphate receptors (IP₃Rs) and lysosomal Ca²⁺ mobilisation through two-pore channels (TPCs). Sustained Ca²⁺ elevation is primarily mediated by influx through transient receptor potential vanilloid 4 (TRPV4) channels, with a minor contribution from store-operated Ca²⁺ entry. The AA-induced Ca²⁺ signal stimulates endothelial NO synthase-dependent NO production, which in turn triggers ROS generation, revealing a tightly coupled Ca²⁺–NO–ROS signalling network. Our findings identify AA as a potent modulator of Ca²⁺ and redox signalling in lung fibroblasts, and highlight GPR40, TRPV4, IP₃Rs and lysosomal TPCs as potential therapeutic targets for intervening in pulmonary fibrosis. Full article

Toxoplasmosis, caused by the obligate intracellular parasite T. gondii, is one of the most prevalent parasitic infections worldwide, affecting approximately one-third of the global population. Despite decades of intensive research, no effective human vaccine exists. The only commercially available vaccine, Toxovax, is restricted to veterinary use in sheep and is unsuitable for human application due to safety concerns. Beyond summarizing the literature, this review offers a critical appraisal of why translation has stalled and where the field should focus next. Live-attenuated vaccines remain the most immunogenic in preclinical models but face significant translational barriers for human use. Key antigenic targets include surface antigens (SAG), dense granule antigens (GRA), rhoptry proteins (ROP), and microneme proteins (MIC). Protective immunity relies critically on Th1-type immune responses characterized by interferon-gamma production. Major obstacles include the parasite’s complex life cycle, strain diversity, and difficulty achieving sterile immunity. Subunit and mRNA-based platforms offer more favorable safety profiles and established clinical precedents, representing the most viable pathway toward a human vaccine. Recent advances in CRISPR/Cas9 gene editing and emerging mRNA vaccine platforms offer promising new directions. This review advances the field in three ways. (i) It prioritizes mRNA and adjuvanted subunit formulations targeting multistage conserved antigens as the most realistic near-term human candidates. (ii) It identifies the limited targeting of bradyzoite-stage biology as a principal, under-addressed gap. (iii) It argues that future development must be differentiated into three complementary One Health goals—prevention of congenital disease in humans, reduction in tissue-cyst burden in livestock, and interruption of environmental transmission by vaccinating cats. In practice, a veterinary-first deployment strategy is the most immediate and impactful pathway to reducing the human and zoonotic burden of toxoplasmosis. Full article

Air pollution is a growing hazard to global health. Epidemiological studies have reported a potential role of air pollutant exposure in the development or aggravation of neurodegenerative diseases. However, the underlying mechanisms are ill-defined. Ferroptosis is an iron- and reactive oxygen species (ROS)-dependent form of cell death that drives neuronal loss in neurodegenerative diseases. Our previous studies reported the involvement of adenosine 3′,5′-cyclic monophosphate (cAMP) and EPAC (exchange protein directly activated by cAMP) in ferroptotic cell death. Here, we investigated the effects of diesel exhaust particles (DEP) in mouse hippocampal (HT22) neuronal cells. Our data showed that toxicity induced by RSL3 (50–75 nM), a ferroptosis inducer, was significantly increased by the addition of DEP (100 μg/mL). Pharmacological inhibition of EPAC1 (CE3F4 30 μM or AM-001 30 μM) and soluble adenylyl cyclase (sAC; TDI-10229 1 μM or TDI-11861 0.1 μM) prevented enhanced ferroptotic HT22 cell death caused by DEP, while pharmacological modulation of EPAC2, protein kinase A (PKA), phosphodiesterases (PDEs), or transmembrane AC did not. DEP in combination with RSL3 exposure increased intracellular calcium levels and induced lysosomal de-acidification. Furthermore, inhibition of EPAC1 prevented mitochondrial ROS (MitoSOX) and lipid peroxidation (BODIPY C11 and MDA levels) after DEP and RSL3 co-exposure. Collectively, EPAC1 may serve as a novel target for the treatment or prevention of neurodegenerative diseases accelerated by air pollution. Full article

Neurodegenerative diseases, characterized by progressive neuronal loss and functional decline, impose a substantial global health burden. Autophagy, the principal intracellular degradative pathway for clearing misfolded proteins and damaged organelles, is vital for neuronal homeostasis, whereas maladaptive neuroinflammation is increasingly being recognized as a central driver of disease progression. A growing body of evidence indicates a bidirectional, tightly coupled relationship between autophagy and neuroinflammation: impaired autophagic flux promotes accumulation of damage-associated molecules that activate innate immune responses, while sustained inflammatory signaling further disrupts autophagy, together forming a self-reinforcing cycle that accelerates neurodegeneration. This interplay is regulated by diverse genetic, molecular, cellular, and environmental factors and manifests in cell-type-specific ways across microglia, astrocytes. Therapeutic strategies emerging from these insights include modulation of autophagic pathways (e.g., mTOR, AMPK, TFEB), targeted inhibition of inflammasome and pro-inflammatory mediators (notably NLRP3-related signaling), and delivery platforms for small molecules or nucleic acids, with increasing interest in multi-target and stage-specific interventions. This review integrates mechanistic evidence and translational advances, highlights gaps in cell-type and stage-specific understanding, and outlines priorities for developing safe, effective therapies that target the autophagy–neuroinflammation axis in neurodegenerative disorders. Full article

Infectious diseases remain a major global health challenge, driven by antimicrobial resistance, pathogen persistence, and the limited integration of mechanistically innovative therapeutic approaches. Emerging evidence indicates that epigenetic regulation is fundamental to host–pathogen interactions, influencing transcriptional programmes associated with virulence, immune evasion, stress adaptation, and phenotypic plasticity. In organisms such as bacteria, parasites, and intracellular pathogens, including Mycobacterium tuberculosis and Plasmodium falciparum, chromatin-associated regulators and DNA-modifying enzymes have been identified as dosage-sensitive determinants of infection outcomes. Traditional strategies focus primarily on occupancy-driven enzymatic inhibition. In contrast, targeted protein degradation (TPD) introduces an event-driven pharmacological paradigm in which transient ligand engagement triggers sustained depletion of regulatory proteins. Platforms such as proteolysis-targeting chimeras (PROTACs) and BacPROTACs exemplify the ability to exploit host and pathogen proteolytic systems, thereby expanding the druggable proteome beyond conventional small-molecule targets. This review examines the relationship between epigenetic regulation and pathogen survival, highlights recent advances in degradation technologies, and discusses conceptual and translational challenges in implementing TPD in antimicrobial and antiparasitic drug discovery. Full article

Background: Terahertz (THz) waves exhibit both photon-like and electron-like properties, showing emerging potential in biomedical applications. Cutaneous squamous cell carcinoma (CSCC) is one of the most common skin tumors. Studies have reported that THz waves can induce apoptosis in cancer cells or ablate tumor tissues. Our previous studies also confirmed that 0.1 THz radiation could significantly promote apoptosis in cutaneous melanoma cells, while it had no apparent effect on fibroblast viability, proliferation, migration, and apoptosis. However, the effects of 0.1 THz radiation on CSCC cells have not yet been explored. Furthermore, there remains a lack of investigation into the structural and functional effects on fibroblasts. Therefore, it is necessary to conduct a systematic study to evaluate the influence of 0.1 THz radiation on both CSCC cells and fibroblasts in order to better understand its potential therapeutic applications in the treatment of skin cancer. Purpose: This study aims to explore the biological effects of 0.1 THz radiation on SCC-7 cells and to uncover the molecular mechanisms underlying THz-induced apoptosis, as well as its potential effect on L-929 cells. Methods: Cell viability was evaluated through the CCK-8 assay, while cell cycle distribution was analyzed with the DNA content detection kit. Wound healing assays were performed to assess cell migration, and Annexin V-FITC staining was used to detect apoptosis. Caspase-3 activity was measured using the caspase-3 activity assay kit. Cell morphology was observed using the Atomic Force Microscope (AFM) and the Transmission Electron Microscopy (TEM). Alterations in membrane potential were detected with the M09 membrane potential probe kit, and intracellular Ca²⁺ levels were quantified using the Fluo-8 AM fluorescent probe. Mitochondrial permeability transition pore (mPTP) opening was assessed with the MPTP detection kit, mitochondrial membrane potential changes were measured using the JC-1 probe kit, and cellular ATP levels were measured with the enhanced ATP assay kit. Subsequently, proteomic analysis was performed. Intracellular reactive oxygen species (ROS) levels were quantified with the ROS detection kit, and cytochrome c (Cyt c) release was quantified using the mouse Cyt c ELISA kit. Apoptosis-inducing factor (AIF) expression was analyzed at both mRNA and protein levels by quantitative real-time PCR (qPCR) and Western blot. AIF expression in CSCC tissues was further evaluated based on the GSE42677 and GSE45164 databases. Finally, cyclosporin A (CsA) was used to inhibit mPTP, and in combination with the iMAC inhibitor, the Aifm1 expression and Cyt c release were examined. Results: Our results showed that THz waves significantly disrupted the membrane integrity of SCC-7 cells and induced mitochondrial structural and functional damage. This resulted in a significant increase in ROS levels and the activation of mPTP and the mitochondrial apoptosis channel (MAC). THz radiation promoted the release of Cyt c and AIF from mitochondria, triggering a noncanonical caspase-3-dependent apoptosis pathway. Notably, L-929 cells did not show significant phenotypic or apoptotic changes under the same irradiation conditions. Bioinformatics analysis of the Gene Expression Omnibus (GEO) database revealed that AIF expression was significantly altered in CSCC tissues compared to normal skin tissues. Conclusions: These findings indicated that 0.1 THz radiation effectively induced apoptosis in SCC-7 cells by triggering mitochondrial dysfunction and ROS generation, which led to the release of AIF. Furthermore, the dysregulation of AIF in CSCC tissues suggested its potential as a promising biomarker. These results provided important molecular insights into the therapeutic potential of THz radiation, particularly for the treatment of cutaneous squamous cell carcinoma. Full article

The Mycobacterium tuberculosis bacterium encodes two active potassium (K⁺)-uptake transport systems, the Trk and the Kdp. The Trk is the low-affinity K⁺ transporter, consisting of two TrkA proteins, while the Kdp consists of the high-affinity K⁺ transporter KdpFABC and the two-component system KdpDE. Both transporters are utilised by the bacteria for growth and survival. During growth, the bacteria utilise the constitutively expressed Trk and suppress the Kdp, but upregulate both transporters during survival. In the current study, we investigated the interactive effects of these systems on bacterial growth and survival. This was achieved by first constructing a M. tuberculosis mutant strain in which both the Trk and Kdp systems were inactivated by homologous recombination. The mutant was evaluated for its growth kinetics in planktonic cultures, as well as survival in biofilm and macrophage cultures. The constructed M. tuberculosis mutant showed faster growth rates in planktonic cultures, but was attenuated for both biofilm formation and intracellular survival in isolated human monocyte-derived macrophages. These results illustrate that both K⁺-uptake systems are essential to sustain slow rates of bacterial growth, as well as for bacterial persistence in hostile environments via optimisation of biofilm formation, and intracellular survival in macrophages. (Words: 194) Full article

MicroRNAs (miRNAs) play important roles in the regulation of gene expression and are frequently dysregulated in cancer. Among them, the miR-196 family has been implicated in multiple malignancies, including colorectal cancer (CRC), but the isoform-specific transcriptional effects of miR-196A and miR-196B remain poorly understood. In this study, we generated miR-196A and miR-196B knockout SW48 CRC cell lines using CRISPR-based genome editing and performed RNA sequencing to investigate the transcriptional consequences of individual miR-196 isoform deletion. Transcriptomic analysis revealed widespread gene expression changes in both knockout models and demonstrated distinct clustering patterns between parental SW48 cells and miR-196-deficient cells. Functional enrichment analysis indicated that the altered genes were associated with biological processes related to cytoskeletal organization, intracellular transport, protein folding, and metabolic regulation. Notably, both shared and isoform-specific transcriptional alterations were observed, suggesting that miR-196A and miR-196B contribute to partially overlapping but distinct regulatory networks in CRC cells. Collectively, these findings provide a comprehensive transcriptomic overview of miR-196 isoform deletion in colorectal cancer cells and highlight potential isoform-dependent transcriptional programs that may contribute to CRC biology. Full article

Neurodegenerative disorders, including Parkinson’s disease (PD), are largely treated with symptomatic therapies, underscoring the need for strategies that target underlying disease mechanisms. Glucagon-like peptide-1 (GLP-1) and its receptor (GLP-1R), a class B G protein-coupled receptor best known for metabolic regulation, have attracted interest due to the increasing evidence of central nervous system (CNS) actions. This review synthesises mechanistic, preclinical, and clinical evidence examining GLP-1R signalling in PD and related neurodegenerative contexts. We integrate findings from cellular and animal models with early-phase clinical studies of GLP-1 receptor agonists (GLP-1RAs). Across experimental systems, GLP-1R activation engages conserved intracellular pathways—cAMP/PKA, PI3K/Akt, and ERK—that regulate mitochondrial function, oxidative stress, autophagy-lysosomal dynamics, and inflammatory signalling. In PD-relevant models, these pathways intersect with key pathogenic features, including α-synuclein accumulation, dopaminergic neuron vulnerability, and glial reactivity. Clinical studies to date demonstrate acceptable safety and tolerability, alongside biomarker evidence of central pathway engagement and variable effects on motor and non-motor outcomes. However, uncertainties remain regarding CNS target engagement, peripheral versus CNS mechanisms, and disease-stage dependence. Overall, the current evidence positions GLP-1R signalling as a biologically plausible therapeutic pathway in PD that warrants further mechanistic clarification and rigorous evaluation in ongoing and future clinical trials. Full article

Background/Objectives: The escalating crisis of antibiotic resistance and the inherent limitations of conventional antibiotics necessitate the development of innovative therapeutic strategies. Targeted drug delivery (TDD) offers a powerful approach to enhance efficacy, minimize systemic toxicity, and circumvent bacterial resistance. This systematic review aims to evaluate the potential of unique bacterial transport systems (BTSs), surface specific receptors and intracellular enzymes as platforms for TDD via the “Trojan Horse” strategy (THS). Methods: A comprehensive literature review was conducted, focusing on studies that investigated the specificity and mechanisms of BTSs responsible for the uptake of metabolites that are essential for and unique to bacteria. This includes an analysis of transport systems for siderophores, bacteria-specific sugars, cell wall components, D-amino acids, and vitamins. We assessed preclinical and clinical examples of drug conjugates utilizing these pathways, as well as emerging platforms such as bacteriophage-derived proteins, antibody–antibiotic conjugates, and bacterial extracellular vesicles (EVs). Results: BTSs demonstrate high specificity for their cognate substrates, providing effective molecular gateways for TDD of drugs photosensitizers and diagnostic probes in form of conjugates. The siderophore–cephalosporin conjugate cefiderocol represents a clinically validated example, having received FDA approval. Preclinical studies further reveal that conjugates utilizing sugars (e.g., maltose, trehalose) and vitamins (e.g., B12) can significantly enhance antibiotic uptake and activity against both Gram-positive and Gram-negative pathogens, including drug-resistant strains. Emerging platforms like bacteriophage endolysins and engineered EVs show promise for overcoming biological barriers such as bacterial outer membranes and intracellular host niches. Conclusions: The THS leveraging BTSs represents a clinically viable and promising avenue for next-generation antibacterial therapies. Advantages of BTS include overcoming bacterial resistance, such as reduced membrane permeability and efflux pumps, enabling the “revival” of antibiotics that are poorly permeable or toxic, increasing their local concentration at the target site and reducing side effects on host cells. While significant progress has been made, a striking disconnect persists between the hundreds of conjugates demonstrating potent in vitro activity and the limited agent that has achieved clinical use. This in vitro–in vivo gap reflects, in large part, the early stage of this field rather than a fundamental failure. Further research is critically needed not only to identify novel BTSs and optimize drug-linker chemistry, but also to systematically address the translational barriers—including poor pharmacokinetics, immunogenicity, and unexpected toxicity—that have prevented most promising candidates from advancing beyond preclinical evaluation. Full article