Search Results (618)

Background: The combination of conventional drugs and inhibitors of signaling molecules is an effective strategy to increase cancer treatment efficacy and reduce drug doses to protect against their cytotoxic effects. Our research has shown the cisplatin concentration-dependent shift in the role of MAP kinase JNK from antiapoptotic to proapoptotic in non-small cell lung cancer A549 cells. Cell death/survival signaling molecules, tumor suppressor p53 and pro-survival protein kinase AKT were detected to be differently regulated by JNK inhibition at low vs. high cisplatin concentrations. Here, we further investigated the phenomenon and potential mechanisms of combined JNK inhibition and cisplatin treatment. Methods: Cell death in vitro was evaluated by MTT and Western blot assays after combined cisplatin and specific inhibitor treatment; two-way ANOVA was used for analysis. Results: JNK is differently involved in determining cellular sensitivity to different DNA-damaging drugs. There is no universal cell death induction mechanism originating from DNA damage through the involvement of JNK. The outcome of JNK inhibition also depends on the cell type. We found that there is an unusual reciprocal interaction between p53 and AKT in cisplatin-treated A549 cells, where p53 inhibits AKT, while AKT activates p53. In the case of cisplatin + JNK inhibitor SP600125, DNA damage and reactive oxygen species (ROS) contribute to cell death regulation in different ways. ROS exert opposite roles on cell fate-determining molecules p53 and AKT, and ROS act on p53 and AKT in opposite directions at low vs. high concentrations of cisplatin, combined or not with JNK inhibition. The differentially activated p53 in response to ROS (at low versus high concentrations of cisplatin, combined with JNK inhibitor) may be a molecular switch in the role of JNK from antiapoptotic to neutral/proapoptotic, and an executor of cell death. ROS is a possible threshold regulator that, together with an as-yet-unidentified factor, can differentially regulate p53. As a result, AKT phosphorylation and function are altered. The findings emphasize the importance of assessing the role of drug concentration when combining them with JNK inhibition when monitoring therapeutic efficacy and toxicity issues in personalized cancer treatment. Full article

The role of platelet-derived growth factor D (PDGFD) in mesenchymal cells is well-established, but its specific function in skeletal muscle generation remains unknown. This study reveals for the first time PDGFD’s dual regulatory role in myogenesis: it acts both as a “guardian” maintaining the myoblast pool and as an “initiator” driving myogenic differentiation. Through single-cell RNA sequencing analysis of skeletal muscle from Jiangquan Black pigs, we identified PDGFD as a common candidate gene for both muscle and fat development. In the C2C12 cell model, PDGFD knockdown significantly inhibited cell proliferation and promoted apoptosis, while overexpression enhanced viability and inhibited apoptosis, indicating its critical role in maintaining myoprogenic precursor cell homeostasis. Further studies revealed that PDGFD interference downregulated key myogenic differentiation markers MyoD and MyoG, inhibiting differentiation. Its expression peaked during mid-differentiation (D5), suggesting temporal regulation of differentiation. Interestingly, although PDGFD primarily acts through the PI3K/Akt pathway downstream of PDGFR-β, PDGFD knockdown did not show significant synergistic effects with PI3K/Akt pathway activation in inhibiting differentiation. This suggests PDGFD may specifically regulate myogenic differentiation via an independent or parallel signaling axis. This study not only expands the known functions of PDGFD in muscle biology but also provides new insights into the mechanisms by which growth factors coordinate cell fate decisions. Full article

Background: The principal glial cells of the retina, Müller glia, play a central role in retinal regeneration in teleost fish and have recently attracted attention as potential sources of neuronal regeneration in mammals. Objectives: In this study, we examined whether SV40-immortalized rat Müller glia could be directed toward neuronal differentiation using a non-genetic approach with defined culture conditions. Methods: Comprehensive transcriptomic profiling by RNA sequencing indicated that changes in culture medium alone could induce transcriptional reprogramming toward a neuronal lineage. Results: Specifically, expression of Müller glia-related genes decreased, while a subset of photoreceptor-related transcription factors and specific genes showed altered expression, suggesting early-stage induction toward a photoreceptor-like fate. This finding suggests that even immortalized cells may exhibit activation of neuronal genes through non-genetic culture interventions. Gene set enrichment analysis further revealed upregulation of pathways related to the synaptic vesicle cycle, metabolic activation, oxidative stress defense, and lysosomal function, consistent with initiation of neuronal differentiation. Conversely, pathways associated with cell cycle regulation and stemness signaling were downregulated, reflecting a transition from a proliferative to a differentiation-prone state. Collectively, these results provide preliminary molecular markers for early neuronal induction and potential targets for chemical screening. Conclusions: Importantly, this strategy enables neuronal-like differentiation of Müller glia without genetic manipulation, offering a safe and cost-effective platform. Overall, our findings may support the development of in vitro models for retinal neuroregeneration and facilitate research toward regenerative therapies for retinal disorders. Full article

Transcriptional regulation is pivotal for developmental processes and cell fate specification in homeostasis. One particularly relevant group of transcription factors is the sine oculis homeobox (SIX) family, which is involved in a wide range of molecular processes from development to tissue maintenance. Within this family, distinct subfamilies exhibit specific DNA-binding preferences and can function as transcriptional activators or repressors. In this review, we focus on the Optix/SIX3–SIX6 subfamily and discuss their roles as transcriptional regulators, as well as the consequences of their deregulation for neuronal and ocular development and for the maintenance of tissue homeostasis. We further examine how SIX3 can act either as a tumour suppressor or as a marker of poor prognosis in different cancer types. Moreover, we summarize recent findings on the role of SIX3 in pancreatic β cells and highlight emerging evidence that SIX2 also contributes to β-cell identity and regulatory stability. Downregulation of SIX2 and SIX3 alters gene regulatory programs associated with β-cell homeostasis and contributes to type 2 diabetes. As accumulating evidence links members of the SIX family to cancer and metabolic disease, it is crucial to characterize how these transcription factors regulate cell identity, with important implications for disease mechanisms and therapeutic strategies. Full article

Type I interferons (IFN-I) are pleiotropic cytokines best known for their antiviral impacts. However, they are known to also impact immune responses outside of viral infection through directly signaling many populations of innate and adaptive immune cells. Here, we focus on the complex body of findings from viral, bacterial, and parasitic infection models, cancer and autoimmunity studies, as well as in vitro experiments using human and murine T cells, demonstrating that IFN-I can be directly sensed by CD4 T cells. Such signaling has been shown to influence many central aspects of antigen-specific CD4 T cell responses, including proliferation, apoptosis, effector subset differentiation, and memory formation. These effects are frequently divergent and sometimes opposing, likely reflecting how differences in variables related to the IFN-I signal, overall inflammatory milieu, and the CD4 T cell integrate to shape outcomes. Indeed, we discuss findings supporting a framework in which dynamic engagement of canonical and non-canonical signaling pathways downstream of IFN-I, which are contingent on a cell’s activation state, play a key role in determining whether and how IFN-I promotes, restrains, or otherwise reprograms CD4 T cell fates. Together, these observations highlight the impressive scope of regulation that IFN-I signals to CD4 T cells can exert, parallel to its actions on other immune and non-immune cell types. They also suggest that harnessing such signaling could offer powerful therapeutic strategies to shape CD4 T cell immunity in diverse context-dependent situations. Full article

Dysregulation of iron and copper homeostasis is a pivotal driver of regulated cell death through two distinct yet interconnected modalities: ferroptosis and cuproptosis. This comprehensive review evaluates the therapeutic modulation of these metal-driven pathways within a dual paradigm: their deployment as a cytotoxic weapon in oncology and their inhibition for neuroprotection. We synthesize evidence ranging from small-molecule synergy to advanced nanomedicine, examining how the interplay between iron and copper governs cellular fate in resistant malignancies and neurodegenerative diseases such as Parkinson’s disease and Multiple Sclerosis. In oncology, bimetallic nanoplatforms and CRISPR-Cas9 nano-ionophores exploit “iron addiction” and metabolic vulnerabilities to induce fatal lipid peroxidation and FDX1-mediated proteotoxic stress, often by circumventing efflux transporters like ATP7A/B. Conversely, neuroprotective strategies focus on site-specific chelation, utilizing brain-penetrant molecules like SK4 (targeting the LAT1 transporter) and radical trapping antioxidants like Cu^II(atsm). Importantly, we elucidate the “iron trap” mechanism, where copper deficiency inactivates multicopper ferroxidases—including ceruloplasmin and hephaestin—thereby triggering iron-dependent ferroptosis. Our analysis reveals a self-amplifying cycle of oxidative damage driven by metal-induced ATP depletion and glutathione exhaustion. By delineating the molecular machinery of iron and copper metabolism, this article provides a roadmap for leveraging regulated cell death to overcome apoptosis resistance in cancer and preserve neural integrity in chronic degeneration. Full article

Background/Objectives: Bone marrow adipose tissue (BMAT) serves multiple physiological roles but accumulates with age, compromising skeletal health. This expansion is largely driven by an adipogenic drift of bone marrow mesenchymal stromal cells (BMSCs), shifting attention toward stromal cell fate regulation as a target to preserve bone marrow homeostasis. Preventing adipogenic commitment may be as relevant as directly inducing osteogenesis for maintaining a bone-permissive marrow microenvironment. Here, we investigated whether olive leaf extract (OLE) and its purified secoiridoid components, oleacin (OC) and oleuropein aglycone (OA), modulate the adipogenic differentiation and proliferative capacity of human BMSCs. Methods: Human BMSCs were induced to undergo adipogenic differentiation and treated with OLE, OC, or OA. Intracellular lipid accumulation and the expression of key adipogenic regulators were assessed. Proliferative capacity was evaluated under both maintenance and adipogenic conditions. Results: Under adipogenic conditions, OLE markedly reduced intracellular lipid accumulation and induced a coordinated downregulation of PPARγ, PLIN1, FABP4, ADIPOQ, LEP and the adipogenesis-associated miR-422a. In contrast, OC and OA exerted more selective and specific effects on biomarkers, indicating the partial and complementary modulation of adipogenic programs. Notably, OLE also increased BMSC proliferation under both maintenance and adipogenic conditions, suggesting the preservation of a less committed stromal cell pool. Although the relative contribution of enhanced proliferation versus the direct inhibition of adipogenic pathways cannot be fully disentangled, the combined molecular and functional data support a dual action of OLE on stromal cell fate. Conclusions: OLE limits adipogenic commitment while maintaining stromal cell proliferative competence, processes that are critically involved in BMAT expansion and bone marrow dysfunction. OC and OA contribute to OLE bioactivity deserving further investigation, particularly in combination, as potential modulators of BMAT expansion. Full article

Periodontal disease is a chronic inflammatory condition that destroys tooth-supporting tissues, particularly the alveolar bone and the periodontal ligament, and effective regenerative therapies remain limited. While the role of metabolic–epigenomic crosstalk in determining cell fate is well established, the specific mechanism by which a tricarboxylic acid (TCA) cycle metabolite can modulate chromatin regulation to promote periodontal regeneration remains to be elucidated. The impact of one TCA cycle metabolite, alpha-ketoglutarate (α-KG), was examined in human periodontal ligament fibroblasts cultured under osteogenic induction and profiled by ALP assays, RT-qPCR, analyses of multiple histone modifications, ATAC-seq, and RNA-seq. α-KG increased ALP activity and upregulated genes associated with osteogenesis and the extracellular matrix (ECM). ATAC-seq revealed minimal genome-wide accessibility changes, whereas histone analyses showed reduced H3K27me3, consistent with an epigenetic mechanism that does not require extensive chromatin opening. The RNA-seq identified 14 upregulated α-KG-induced genes, including multiple components of the OGN-OMD-PLAP1/ASPN-ECM2 loci, supporting an osteogenic/ECM transcriptional program. In a mouse periodontal regeneration model, oral administration of α-KG enhanced alveolar bone regeneration and reduced H3K27me3 signals and collagen-rich tissue organization within the periodontal ligament space. These findings identify α-KG as a metabolite-driven epigenetic modulator that alleviates H3K27me3-mediated repression and supports periodontal regeneration. Full article

Breast cancer is the leading cause of cancer-related death in women, and despite advances in preventive screening as well as in molecular classification, many patients still do not benefit from existing therapies, highlighting the importance of identifying new molecular determinants of treatment resistance. The Paired-box (PAX) family of developmental transcription factors are central regulators of tissue morphogenesis and lineage specification, yet their reactivation in tumors and contribution to breast cancer progression remain only partially defined. Here, a multi-level analysis integrating RNA sequencing and protein profiling in twenty-one primary breast carcinomas shows that distinct PAX members are directly correlated to distinct fundamental cancer hallmarks, including proliferation, cell death, epithelial–mesenchymal transition, immune evasion, and genomic instability. Specifically, PAX1 and PAX9 correlates with both cell death and proliferative markers, indicating dual roles in the regulation of cell fate. PAX1 and PAX9 correlate with both proliferative and apoptotic markers, indicating dual roles in cell fate regulation. PAX3, PAX5, and PAX8 are mainly associated with immune checkpoint expression, including PD-L1 and TIGIT, while PAX6 is linked to microsatellite instability and tumor mutational burden, implicating it in genomic dysregulation. Therefore, PAX-based molecular signatures identify that accurately predict lymph node metastasis at transcriptomic (PAX2–PAX7) levels. These findings establish PAX transcription factors as key modulators of breast cancer biology and support their potential as clinically relevant biomarkers for prognostic refinement and therapeutic stratification. Full article

The endoplasmic reticulum (ER) is a central hub of cellular proteostasis, coordinating protein folding, lipid metabolism, calcium signaling, and inter-organelle communication. Disruptions in ER function activate the unfolded protein response (UPR), an evolutionarily conserved signaling network mediated by PERK, IRE1α, and ATF6. Initially viewed primarily as a stress-mitigating mechanism, the UPR is now recognized as a central coordinator of diverse cellular stress-response pathways. This review focuses on mechanistic insights into UPR signaling, with particular emphasis on its crosstalk with oxidative stress regulation, mitochondrial function and mitochondria–ER contact sites, autophagy, inflammatory signaling, and metabolic sensing. The analysis integrates evidence from biochemical and structural studies, genetic and pharmacological perturbation models, and selected in vivo investigations from PubMed and Google Scholar between 2000 and 2025, focusing on mechanistic, experimental and translational studies addressing UPR signaling and ER stress. Together, these studies demonstrate how transient UPR activation promotes cellular adaptation through coordinated transcriptional, translational, and organelle-specific responses. We further discuss how sustained or unresolved ER stress alters UPR outputs, shifting signaling toward maladaptive outcomes such as mitochondrial dysfunction, dysregulated autophagy, oxidative imbalance, and apoptosis. By placing the UPR within a network of interconnected stress pathways, this work provides a framework for understanding how ER proteostasis is linked to cell fate decisions under stress. Full article

Chromatin dynamics are usually modulated by histone epigenetic post-translational modifications, which rapidly and reversibly govern accessibility and transcriptional responsiveness. During microbial infection, this regulatory layer becomes a highly contested interface where host defense mechanisms and pathogen-driven subversion strategies converge and compete. Many infectious agents exploit chromatin to reprogram gene expression, creating cellular environments that are conducive to infection, proliferation, and persistence. Diverse strategies have been described for viruses, bacteria, fungi, protozoa and nematodes, including the direct secretion of acetyltransferases and methyltransferases, interference with host chromatin-binding proteins, subcellular localization of transcriptional factors or epigenetic regulators, and metabolic availability manipulation. Concurrently, host cells activate immune and stress-response genes to mount rapid, adaptable antimicrobial responses. Recent advances in genome-wide, single-cell, and spatial omics profiling have begun to reveal the temporal and cell-type-specific dynamics of the host genome at the core of infection. This review synthesizes current insights into how chromatin is rewired by the major categories of pathogens during infection, highlighting representative case studies across infective agents and the functional consequences for immunity and cell fate. In addition, we discuss emerging techniques for epigenomic and transcriptomic data collection, and the potential of targeted host-directed therapeutic strategies. Chromatin regulation is thus a promising field of study and a possible target for next-generation interventions. Full article

The endoplasmic reticulum (ER) responds to stimuli that disrupts its homeostasis by activating a signalling network known as unfolded protein response (UPR), that restores cellular balance and determines cell fate through three key sensors: inositol-requiring enzyme 1α (IRE1α), activating transcription factor 6 (ATF6), and protein kinase RNA-like ER kinase (PERK). Emerging evidence suggests that UPR regulates the expression of numerous long non-coding RNAs (lncRNAs), which play critical roles in maintaining ER homeostasis. Here we show that expression of lncRNA H19 is downregulated in response to ER stress in (MCF7, T47D and 293T) cells. Using genetic and pharmacological approaches, we demonstrate that H19 downregulation is primarily mediated by the PERK arm of the UPR. Specifically, knockdown or chemical inhibition of PERK compromised the ER stress-mediated H19 repression, while PERK activation significantly reduced H19 expression. H19 overexpression promotes the optimal activation of ATF6 and PERK pathways, while it attenuates the signalling by IRE1-XBP1 axis of the UPR. Furthermore, in triple-negative breast cancer (TNBC) cells MDA-MB-231, ectopic H19 provided resistance to ER stress-induced apoptosis. Bioinformatic analyses across multiple breast cancer cohorts revealed that high H19 expression was associated with poor prognosis, particularly in basal-like subtypes. Collectively, our findings show that H19 is downregulated during UPR in a PERK-dependent manner, where H19 in turn modulates UPR signalling and cell fate during conditions of ER stress. Full article

Precise control of keratinocyte proliferation and differentiation is critical for oral epithelial regeneration, yet the mechanobiological cues guiding these processes remain incompletely defined. Here, we systematically evaluated how electrospun polycaprolactone (PCL) scaffolds with defined fiber orientations (aligned vs. random) and diameters (600–800 nm, 1.2–1.7 µm, 2.0–2.5 µm) direct gingival keratinocyte fate. Using immortalized human gingival keratinocytes, we assessed cell and nuclear morphology, proliferation dynamics, differentiation marker expression, and the effects of basal keratin (KRT5/KRT14) knockdown. Quantitative morphological analysis revealed scaffold-dependent changes in cell shape: aligned medium-diameter fibers (with fiber diameters of 1.2–1.7 µm) induced pronounced cell and nuclear elongation, whereas random fibers (600–800 nm) promoted larger, more rounded cell and nuclear shapes. Time-resolved EdU assays indicated that aligned scaffolds supported sustained proliferation, whereas random scaffolds elicited a transient proliferative burst followed by a decline. Gene expression analysis (ddPCR) demonstrated that random scaffolds (especially 600–800 nm fibers) upregulated basal keratins (KRT5, KRT14) and early differentiation markers (KRT1, KRT10, KRT4, KRT13) relative to aligned scaffolds. At the protein level, differentiation markers involucrin (IVL) and filaggrin (FLG) were likewise elevated on random scaffolds, corroborating the mRNA findings. Functional KRT5/KRT14 knockdown experiments revealed scaffold-specific dependencies: cells on random scaffolds required these keratins for viability, whereas aligned cultures remained viable upon KRT5/14 loss. Furthermore, KRT5/14 depletion differentially altered downstream differentiation markers (IVL, KRT1) and mechanotransduction markers (LMNB1, YAP1) in a scaffold-dependent manner. Collectively, these findings establish fiber orientation and diameter as key design parameters for controlling keratinocyte fate. As a translational concept, layered scaffolds combining aligned and random fibers may enable spatially controlled proliferation and differentiation in engineered oral epithelia. Full article

Nonsense-mediated mRNA decay (NMD) is a highly conserved RNA quality and quantity surveillance machinery in eukaryotic cells, serving as an important node in the post-transcriptional gene expression. Previous studies using the complete knockout of individual NMD factors in cells or animals reveal that NMD deficiency causes developmental defects and compromises tissue homeostasis. However, because most NMD factors participate in multiple molecular functions, a direct link between NMD and cell fate determination is missing. SMG6 is a core NMD effector and the only endoribonuclease among all NMD factors. The NMD function of SMG6 is exclusively mediated by its PIN (PilT N-terminus) domain. In this study, we engineered a mouse model with the capability of specifically deactivating the SMG6’s PIN domain/endoribonuclease activity (Smg6-PIN^F/F), but not knocking out the complete SMG6 protein. We found that SMG6’s PIN domain is essential for NMD activity in embryonic stem cells (ESCs) and various tissues of adult mice. Furthermore, loss of SMG6’s PIN domain is dispensable for the mouse ESC self-renewal, but severely compromises the differentiation, which consequently causes the mutant mice to die during the process of organogenesis. Through the induced deletion of SMG6’s PIN domain in adult mice, we found that loss of SMG6’s NMD function affects the homeostasis of several mouse tissues, including the testis and the intestine. In sum, our study establishes a mechanistic link between NMD per se and cell fate determination of mouse ESCs, as well as in the tissues of adult mice, where cell fate transitions are actively ongoing. The Smg6-PIN^F/F mouse line could be a valuable strain for elucidating the biology of NMD per se. Full article

Singlet oxygen (¹O₂), the excitation stage of the ground-state molecular oxygen, is a fundamental reactive oxygen species (ROS) with important functions in plant growth, development, and stress responses. In plant cells, ¹O₂ is mainly generated in the chloroplast due to photosensitizing activity of tetrapyrroles. Moreover, ¹O₂ can be generated in non-photosynthetic tissues when plants suffer environmental stresses. Although ¹O₂ was initially considered as a cytotoxin—causing merely photooxidative damages, more recent work suggests that ¹O₂ also acts as a signal that either triggers a programmed cell death response or promotes acclimation. The ¹O₂ signaling pathway is distinct and operates independently of other ROS signaling cascades. In Arabidopsis, EXECUTER1 (EX1) protein has been identified as a crucial signaling component that perceives and relays ¹O₂ signals to the nucleus, thereby initiating extensive transcriptional reprogramming. Additionally, oxidative products of carotenoids, such as β-cyclocitral, are also recognized as ¹O₂-derived signaling molecules. Through specific chloroplast-to-nucleus signaling and cross talk with hormone signaling networks—including jasmonic acid (JA) and salicylic acid (SA)—¹O₂ helps finely coordinate plant growth, defense responses, and cell fate decisions under fluctuating environmental conditions. This review aims to summarize current knowledge on ¹O₂ generation and signaling, ¹O₂-induced chloroplast changes under diverse stress conditions, and cross talk between ¹O₂ and phytohormone signaling. Full article