Search Results (1,215)

Non-small cell lung cancers (NSCLCs), most notably adenocarcinoma and large cell carcinoma, have been the most frequently diagnosed lung cancer and continue to represent a leading cause of cancer-related mortality worldwide, largely due to its aggressive growth and limited therapeutic responsiveness. Natural products derived from traditional medicinal plants remain a valuable source for the discovery of novel anti-cancer agents. In this study, the anti-cancer potential of Angiopteris evecta (G. Forst.) Hoffm., a medicinal fern widely used in Thai traditional medicine, was investigated in human NSCLC, A549 and H1299 cells. Subsequential solvent extraction yielded hexane, ethyl acetate, and ethanol fractions, among which the ethyl acetate extract (AE-EA) exhibited the strongest growth inhibitory activity. Bioactivity-guided fractionation of AE-EA by thin-layer chromatography generated an (-)-epi-osmundalactone-rich fraction (OLRF), which contained three closely related lactone/furanone derivatives, with (-)-epi-osmundalactone as the predominant constituent, as determined by NMR analysis. AE-EA and OLRF significantly suppressed NSCLC cell viability and clonogenic survival and induced G0/G1 cell cycle arrest, accompanied by downregulation of cyclin D1, cyclin E1, CDK-2, and CDK-4 (p < 0.05). Both treatments also triggered intrinsic apoptosis, as evidenced by mitochondrial membrane depolarization, reduced expression of Bcl-2, and Bcl-xL, and survivin, and activation of cleaved caspase-9 and caspase-3. Mechanistically, AE-EA and OLRF significantly suppressed mitogen-activated protein kinase (MAPK) signaling through inhibition of ERK1/2, JNK1/2, and p38 phosphorylation in both NSCLC cells (p < 0.05). Collectively, these findings demonstrate that AE-EA and OLRF exert pronounced anti-cancer effects in both NSCLC cells through coordinated inhibition of MAPK signaling, induction of cell-cycle arrest, and activation of intrinsic apoptosis, supporting their potential for further development as plant-derived anti-cancer agents. Full article

Laminar separation bubbles (LSBs) on low-Reynolds-number airfoils are sustained by intrinsic unsteadiness driven by Kelvin–Helmholtz (K-H) growth in the separated shear layer. Using incompressible 2D URANS with the SA-$\gamma$ transition model for a NACA 0012 airfoil at $Re=5.3\times {10}^4$, we reveal that numerical dissipation behaves as a critical bifurcation parameter. Validated against the recent Jardin (2025) experimental benchmark, the physical state correctly resolves the LSB-induced pressure plateau ($C_p$) and local negative skin friction ($C_f<0$). However, when numerical dissipation exceeds the K-H instability growth rate, the physical limit-cycle oscillation collapses into a spurious fixed-point attractor—a phenomenon defined as numerical quenching. This pseudo-convergence triggers a catastrophic ∼30% deficit in mean lift ($C_l$). Furthermore, at $\alpha =6^{\circ }$, a drag-mechanism inversion is identified: while the physical branch is dominated by LSB-induced pressure (form) drag, the quenched branch exhibits a non-physical drag surge that exceeds the fully turbulent baseline. Phase portraits and power spectral densities ($St\approx 0.2$) provide objective diagnostics, demonstrating that standard residual convergence is a deceptive indicator of physical fidelity in transitional separated aerodynamics. Full article

The physicochemical controls on gold precipitation in orogenic gold deposits remain poorly constrained, with traditional fluid inclusion and isotopic studies often yielding ambiguous results due to overprinting or incomplete records. This study addresses this challenge using chlorite—a sensitive mineral proxy for fluid conditions—as a quantitative sensor in the Jinshan orogenic gold deposit (>200 t Au) of the Jiangnan orogenic belt, South China. Hosted in Neoproterozoic phyllite within NE–NNE-trending ductile–brittle shear zones, Jinshan features auriferous quartz–polymetallic sulfide veins with prominent chlorite alteration. Integrating high-resolution SEM-EPMA analyses of multi-generational chlorite with thermodynamic modeling, we reconstruct the temporal evolution of temperature, oxygen fugacity (fO₂), pH and sulfur fugacity (fS₂) during ore formation. Four paragenetic stages are identified: Stage 1 (ankerite–quartz), Stage 2 (pyrite–arsenopyrite–quartz), Stage 3 (quartz–gold–polymetallic sulfide), and Stage 4 (chlorite–carbonate–quartz). Electron microprobe analysis reveals that the chlorite composition changes from Fe-rich chamosite (Stage 2) to Mg-rich clinochlore (Stage 3) and then to Fe-rich chamosite (Stage 4). Chlorite from Stage 2 (Chl-1) formed metasomatically at low fluid/rock ratios, while Stage 3 and 4 chlorites (Chl-2 and Chl-3) precipitated directly from higher fluid/rock ratio fluids. Chlorite compositions record a critical Stage 2–3 transition involving cooling from ~ 320 °C to ~ 260 °C, reduction (log fO₂ from –33.6 to –39.7), and alkalinization, and sulfur fugacity remained stable within a narrow range (log fS₂ = –13.6 to –8.0), followed in Stage 4 by minor reheating to ~280 °C, re-acidification, and a slight rebound in oxygen fugacity. Thermodynamic simulations reveal that the destabilization of Au(HS)₂^- complexes, primarily driven by the synergistic effects of cooling, pH increase, and decreasing oxygen fugacity, triggered gold precipitation during the main ore stage. Results demonstrate that abrupt cooling coupled with fluid alkalinization and reduction exerted the dominant control on gold precipitation in Jinshan, resolving long-standing debates on ore-forming mechanisms and highlighting chlorite as a robust quantitative sensor for fluid evolution. Full article

Background: Stimuli-responsive hydrogels (SRHs) are smart polymeric materials that undergo reversible physicochemical changes in response to abiotic cues and externally applied fields, enabling applications in drug delivery, wound healing, and tissue engineering. However, they exhibit limited biological specificity and do not adequately reflect the dynamic, disease-relevant complexity of native tissue microenvironments. Microbe-colonized tissues display distinctive biochemical features driven, shaped by microbial metabolism, including localized pH gradients, short-chain fatty acid production, secretion of quorum-sensing molecules, biofilm formation, and expression of specialized enzymes. These endogenous, spatiotemporally regulated signals are closely linked to host physiology and pathology but remain underutilized in hydrogel design. This review aims to highlight microbiome-responsive hydrogels (MRHs) as a strategy to address this gap. Methods: This study summarizes current engineering approaches, key microbial stimuli, and emerging biomedical applications of MRHs, with emphasis on translational and regulatory challenges. Results: Microbiome-responsive hydrogels (MRHs) address this gap by leveraging microbial metabolic and biochemical cues to induce swelling, degradation, drug release, antibacterial activity, or structural transformation. By directly coupling to microbe-derived stimuli, MRHs offer improved physiological relevance, enhanced local specificity, and new opportunities for precision therapy targeting disease-associated microbial niches. Conclusions: Despite their promise, MRHs remain an early and fragmented field, lacking standardized biological triggers, material design frameworks, and performance evaluation strategies. This review summarizes current engineering approaches, key microbial stimuli, and emerging biomedical applications, with emphasis on translational and regulatory challenges, positioning MRHs as an underexplored platform for next-generation smart biomaterials. Full article

This study investigates the mitochondrial transcriptomic responses of Ramulus phyllodeus (Chen & He, 2008); Phasmatodea: Phasmatidae) to acute exposure to four widely used neurotoxic insecticides: chlorpyrifos, cyfluthrin, emamectin benzoate, and acetamiprid. Using quantitative real-time PCR (qRT-PCR), we quantified transcriptional changes in 10 mitochondrial protein-coding genes, which showed significant transcriptional changes (p < 0.05) when the insect was exposed to four commonly used pesticides (each at a concentration of 5 μg/L) for 24 h. Exposure to chlorpyrifos induced significant upregulation of ND2 (2.08 ± 0.048) and ND5 (1.38 ± 0.15). Cyfluthrin triggered coordinated upregulation across seven genes: ND1 (1.71 ± 0.07), ND2 (2.33 ± 0.38), ND3 (1.74 ± 0.25), ND5 (1.65 ± 0.38), COX1 (2.91 ± 0.40), COX3 (1.69 ± 0.18), and Cytb (2.81 ± 0.53). Emamectin benzoate induced the upregulation of ND1 (1.98 ± 0.21), ND2 (3.04 ± 0.41), ND3 (1.82 ± 0.26), ND4 (2.79 ± 0.64), COX1 (2.36 ± 0.34), ATP6 (3.26 ± 0.61), and Cytb (2.39 ± 0.81). Acetamiprid induced more selective upregulation, affecting only ND1 (1.67 ± 0.18), ND4 (1.43 ± 0.16), and ND5 (1.66 ± 0.10). Critically, each insecticide elicited a distinct, non-overlapping transcriptional signature, defined by both the identity and magnitude of responsive genes, indicating compound-specific modulation of mitochondrial gene expression. Notably, no gene exhibited significant downregulation under any single-compound treatment, and all differentially expressed genes were upregulated exclusively in response to individual pesticides. This absence of transcriptional suppression suggests that these neurotoxicants converge on shared upstream stress-response pathways that preferentially activate mitochondrial biogenesis or compensatory transcription, rather than inducing global transcriptional repression. Collectively, these findings establish mitochondrial protein-coding genes in R. phyllodeus as sensitive, mechanistically grounded molecular sentinels for neurotoxic pesticide exposure. The compound-specific transcriptional profiles further suggest potential utility in multiplex detection strategies for environmental monitoring, enabling discrimination among individual residues. Full article

Aluminum (Al) toxicity is a major constraint on crop growth and productivity in acidic soils, affecting root development, nutrient uptake, and photosynthetic performance. The use of Si is a promising strategy to overcome the adverse effects of Al toxicity on species of agronomic interest. Between 2020 and 2026, 15 studies across nine species consistently demonstrated that silicon mitigated aluminum toxicity, regardless of their classification as silicon accumulators. In plants, Si mitigates Al toxicity through a combination of physical, chemical, and biochemical mechanisms that operate simultaneously. In the rhizosphere, Si interacts directly with Al³⁺ ions, favoring the formation of hydroxyaluminosilicates (HASs), which reduces the bioavailable fraction of Al. Evidence indicates that solution pH is a critical factor governing HAS formation, with minimal attenuation of Al toxicity observed at pH values below 4.5. Within the plant, Si modulates the antioxidant defense system by enhancing the activity of enzymes such as catalase, peroxidase, and ascorbate peroxidase, thereby reducing oxidative stress typically triggered by Al toxicity. Moreover, Si influences the biosynthesis of lignin and phenolic compounds with Al-chelating capacity, contributing to detoxification at the cellular level. In soybean and rice, Si supply substantially reduced Al deposition in the root apical cell wall, with decreases of approximately 52% and 41.3%, respectively. This reduction was consistently associated with improved root elongation, maintenance of root structural integrity, mitigation of cellular deformation, and preservation of root thickness and vascular organization. Although these mechanisms have been described, a comprehensive synthesis of studies published from 2020 to 2026 has been lacking, particularly regarding the integration of in-plant processes and species-specific responses. This review fills this gap by critically examining recent findings, highlighting the multifaceted role of Si in alleviating Al stress, and discussing implications for agronomic applications in acidic soils. Collectively, the evidence underscores Si as an effective tool to enhance plant tolerance to Al; however, most available evidence is derived from early plant developmental stages and hydroponic or highly controlled systems, which limits the direct extrapolation of these findings to soil and field conditions. Future advances will require studies under soil environments, accounting for species-specific responses, soil properties, management systems, and plant developmental stages. Full article

Valsa canker, caused by Valsa pyri (Vp), severely threatens global pear production. The VAMP72 family modulates plant immunity, but its role in Valsa canker resistance remains unclear. In this study, it was found that PbeVAMP724, encoding a membrane-localized SNARE protein, was significantly induced by Vp infection and Abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA) in the resistant pear rootstock Pyrus betulaefolia. Transient overexpression of PbeVAMP724 in ‘Huangguan’ fruits reduced Vp-induced lesions, and the lesion diameter was reduced by 23.1% at 48 h and 20.0% at 72 h compared to the empty vector control (pFGC-5941), whereas VIGS silencing compromised the resistance. Stable overexpression in suspension cells ‘Duli-G03’ (P. betulifolia) enhanced tolerance to Vp metabolites (VpM), alleviated cell death, and induced ROS bursts and defense responses. Weighted gene co-expression network analysis (WGCNA) revealed that phloem/xylem histogenesis-related genes (GWHGAAYT028948, GWHGAAYT039435) are co-expressed with PbeVAMP724. In conclusion, we demonstrate that PbeVAMP724 integrates hormone signaling, triggers ROS bursts, and activates defense responses to positively regulate resistance to Valsa canker in pear, representing a promising candidate for breeding Valsa canker-resistant pear varieties. Full article

The escalating consumption of red meat is a potent environmental risk factor for inflammatory bowel disease (IBD), which is characterized by compromised expression of the xenobiotic transporter P-glycoprotein (MDR1/ABCB1). While gut microbiota metabolize dietary tryptophan into diverse indole derivatives that function as aryl hydrocarbon receptor (AhR) ligands, their differential regulation of MDR1 remains an unresolved AhR paradox. Here, we investigated the mechanisms by which two distinct metabolites, indole-3-acetic acid (IAA) and skatole, regulate MDR1 expression in human colonic epithelial Caco-2 cells. We observed that IAA selectively enhances MDR1 protein stability via an AhR-dependent pathway without inducing de novo transcription, suggesting a mechanism we term enhanced proteostasis mediated by the AhR-Hsp90 complex. Conversely, skatole, a toxic dysbiotic metabolite linked to red meat intake, triggered a time-dependent depletion of MDR1 and potently abrogated the protective efficacy of IAA. Our findings are consistent with a model in which skatole acts as a putative structural disruptor, potentially destabilizing the chaperone complex essential for MDR1 integrity. This destruction is facilitated by a key bacterial enzyme, indoleacetate decarboxylase (IAD), which is a pH-dependent metabolic switch in the gut. The modern Western diet, characterized by high protein and low fiber content, elevates colonic pH, thereby activating IAD to convert protective IAA into toxic skatole. These findings provide a molecular framework for the red meat–microbiome–barrier failure axis and highlight the restoration of the IAA/skatole balance through dietary intervention as a promising therapeutic strategy. Full article

Mannosylerythritol lipid-B (MEL-B) is a glycolipid whose biological properties have been widely investigated, especially in the skincare, food, and therapeutic fields. Despite this, few studies have addressed the toxicity of this glycolipid in vivo. Therefore, this work aimed to evaluate the in vivo oxidative stress induced by MEL-B in Swiss mice. MEL-B (50 and 150 mg/kg) was administered intraperitoneally at two exposure times, 24 and 72 h. Biochemical damage was quantified in the gastrocnemius, lungs, kidneys, heart, liver, and spleen. This study assessed the levels of reactive oxygen species, oxidative damage markers, antioxidant defenses, protein concentration, triglycerides, creatine kinase (CK-MB), and lactate dehydrogenase (LDH). DCF (2′,7′-dichlorofluorescein), sulfhydryl, and SOD (superoxide dismutase) levels were used to assess oxidative damage and antioxidant defenses in cells. The results indicate that MEL-B did not trigger acute toxicity in the tested animals in a systemic context. Oxidative stress was observed in the liver samples, likely due to the metabolization of MEL-B. The levels of triglycerides and of CK-MB and LDH enzymes did not present any significant alteration (p < 0.05), indicating that glycolipids do not trigger tissue damage. These findings open new perspectives for the safe use of MEL-B in cosmetic and medicinal products. Full article

Polysaccharide–protein composite hydrogels have demonstrated remarkable potential in targeted gastrointestinal delivery owing to their excellent biocompatibility, adjustable physicochemical characteristics, and intelligent responsiveness. This review provides a comprehensive overview of the underlying mechanisms and diverse applications of these composite hydrogels in gastrointestinal targeted delivery, with a particular emphasis on their stimuli-responsive release behaviors triggered by internal and external factors such as pH, enzymes, magnetic fields. Special attention is also given to their advantages in protecting sensitive bioactive ingredients, including curcumin, EGCG, probiotics. Furthermore, this review highlights their capabilities in achieving high encapsulation efficiency, smart controlled release and targeted delivery, while also presenting current challenges associated with material stability, targeting precision, large-scale production, and clinical translation. Finally, future perspectives are discussed, focusing on the development of multi-response system design, innovative biomaterials, advanced manufacturing technology applications, and AI-assisted optimization. These directions aim to provide theoretical foundations and technical strategies for advanced research and practical applications of polysaccharide–protein composite hydrogels in a targeted gastrointestinal delivery system. Overall, this review underscores the significant promise of polysaccharide–protein composite hydrogels as intelligent gastrointestinal delivery platforms and provides a systematic reference for their rational design and future translational development. Full article

Background: When tumors are surgically removed, an immediate rise in circulating tumor cells is often observed, accompanied by several postoperative changes that can enable these cells to evade immune detection and metastasize. The perioperative period following tumor resection can often promote the formation of new distant micrometastatic foci triggered by upregulation of distinct molecules. Our lab previously reported an increase in distinct inflammatory cytokine molecules following surgical resection in prostate, breast, and colorectal cancer patients, and the secretion of these signals begins as early as 2–24 h after surgery. Here, we investigated whether these distinct cytokines could orchestrate the formation of tunneling nanotube (TNT) conduits to enhance cancer cell migration. Methods and Results: Here, we provide supporting evidence that specific pro-inflammatory cytokines upregulated following cancer surgery may be potential triggers of disease recurrence and migration through TNT formation. In the tumor microenvironment, TNTs act as conduits between cancer and normal cells, facilitating the transfer of organelles that contribute to cancer cell survival and metastasis. Here, The effects of TGF-β1, IL-6, and HGF cytokines on the development of TNT conduits between adjacent cancer cells, as well as the effects of oseltamivir phosphate (OP) treatment, were measured using fluorescent microscopy and image analysis software. In PANC-1 pancreatic cancer cells, the addition of these cytokines significantly increased (p < 0.009) the quantity and extent of TNTs compared with untreated control cells. MCF-7 breast cancer cells yielded comparable results, with a significant increase in TNT observed in cells treated with TGFβ-1, IL-6, and HGF. In contrast, SW620 colorectal cancer cells did not express TNTs in response to any of the three cytokines tested. OP treatment with cytokines significantly reduced TNT formation in pancreatic and breast cancer cells, with no effect on the colorectal SW620 cancer cell line. Cell migration in response to cytokines was assessed using the scratch wound assay. Out of the three cell lines analyzed, the PANC-1 cells fully closed after 12 h of the wound gap. In contrast, the SW620 and MCF-7 cells had no significant change in wound closure rate following cytokine treatment. The SW620 cells exhibited a slight but insignificant increase in the wound closure rate with TGFβ-1 and HGF treatment, while IL-6 in the SW620 cells and all three cytokines in the MCF-7 cells were comparable to the control. OP significantly reduced the scratch wound closure rate on PANC-1, SW620, and MCF-7 cells treated with these cytokines. Conclusions: These findings further support the link between perioperative cytokine activity and increased metastatic potential by promoting the formation of intercellular tunneling nanotube conduits. OP, a specific inhibitor of the mammalian neuraminidase-1 (NEU-1) enzyme, disrupts this process. Full article

Thymosin β4 (Tβ4) is a highly acidic, intrinsically disordered 43-amino-acid peptide with diverse biological functions, yet its interactions with metal ions remain poorly understood. In this study, we provide the first experimental demonstration that Tβ4 forms discrete Zn²⁺-bound adducts and undergoes Zn²⁺-induced aggregation under physiological pH conditions. Combining zeta potential analysis, dynamic light scattering (DLS), electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy with elemental mapping (SEM/EDS), we show that Zn(II) binding progressively neutralizes Tβ4’s negative surface charge and triggers a sharp aggregation transition. ESI-MS unambiguously identifies Tβ4/Zn(II) complexes of peptide-to-zinc molar ratio 1:3, while DLS and SEM reveal the formation of compact, low-solubility supramolecular assemblies. NMR measurements support a metal-induced aggregation, confirming the absence of folding upon Zn(II) binding. By quantitatively comparing the experimentally determined critical aggregation concentration with physiologically observed extracellular Zn(II) ranges, we demonstrate that aggregation is unlikely in plasma or basal interstitial environments but may become feasible in Zn-rich microdomains, such as the synaptic cleft, where transient Zn(II) levels can exceed 1 μM. These findings introduce a previously unrecognized dimension of Tβ4 chemistry and suggest that a Zn(II)-mediated supramolecular assembly of Tβ4 could influence peptide behavior in neurological or inflammatory conditions characterized by elevated extracellular Zn(II). This work establishes a foundational biochemical framework for future studies aimed at elucidating the biological implications of Tβ4/Zn(II) complexation and aggregation in vivo. Full article

Background: To evaluate the effects of a motion-triggered neuromuscular electrical stimulation (NMES) shoulder strengthening program on rotational shoulder strength and throwing velocity in healthy, elite-level handball players. Methods: Fourteen male handball players were randomly allocated (1:1) to either the NMES or control group. Participants were assessed by a blinded investigator at baseline and after 6 weeks for clinical status, isometric dynamometer-based external (ER) and internal rotational (IR) maximal shoulder strength, and handball endurance and maximal throwing velocity (7 m free throw). Between time points, NMES subjects completed a standardized motion-triggered NMES shoulder strengthening program (3 sessions/week, 30 min for 6 weeks), whereas controls performed a conventional standardized strength program. Results: After completion of the motion-triggered NMES program, all NMES participants (100%) demonstrated significant gains in isometric ER strength (+1.4 ± 1.1 kg, p = 0.016) compared with 43% of controls, who demonstrated no overall improvement (−0.2 ± 1.8 kg, p = 0.740). Similarly, a significantly greater proportion of NMES participants improved endurance throwing velocity compared with controls (100% vs. 29%, p = 0.004), with a mean increase of +2.9 ± 2.8 km·h⁻¹ (p = 0.0.56). Maximum throwing velocity showed no between-group differences in the proportion of athletes with improved results (p = 0.899). Conclusions: A six-week motion-triggered NMES shoulder strengthening program improved external rotation strength and increased the proportion of athletes demonstrating enhanced endurance throwing velocity under fatigued conditions. However, when compared with conventional exercise alone, NMES did not confer additional benefits for maximal throwing velocity in this study. Therefore, NMES should be regarded as a complementary modality rather than a substitute for established shoulder strengthening exercises. Full article

The oral delivery of polyphenolic compounds such as rosmarinic acid (Ros) is limited by poor gastrointestinal stability and early release, resulting in low bioaccessibility. Herein, carboxymethylated guar gum (cmGG)-based nanoparticles were developed as a pH-responsive colloidal delivery system to enhance Ros stability, prevent early release, and improve intestinal bioaccessibility. In this context, pH-responsiveness refers to pH-dependent modulation of degradation, and stabilization along the gastrointestinal tract, rather than an abrupt pH-triggered burst release. Guar gum was chemically modified to different degrees of carboxymethylation to enhance its colloidal stability under gastrointestinal conditions, reduce polymer degradation, and enable a more controlled release of the phenolic compound Ros. Comparative evaluation of cmGG systems with varying degrees of carboxymethylation revealed that nanoparticles prepared from highly substituted cmGG exhibited superior colloidal stability and acid resistance, contributing to effective protection of Ros under gastric conditions. Ros-loaded guar gum nanoparticles effectively suppressed release at acidic pH while enabling controlled and sustained release at intestinal pH. Simulated gastrointestinal digestion studies demonstrated that Ros-loaded carboxymethylated guar gum nanoparticles significantly enhanced the gastrointestinal stability and bioaccessibility of Ros compared with non-carboxymethylated guar gum nanoparticles. Overall, these findings indicate that the degree of carboxymethylation is a critical design parameter for tuning colloidal behavior and release performance under the varying pH conditions encountered throughout the gastrointestinal tract in guar gum-based nanoparticle systems. Full article

Connexins (Cxs) and pannexin1 (Panx1) form hemichannels (HCs) that enable the exchange of ions and small molecules between the intracellular and extracellular compartments. Since an elevated cytoplasmic Ca²⁺ concentration promotes cell death and elevated HC activity has been implicated in pathological conditions, we investigated whether high HC activity contributes to Ca²⁺ influx and cell death. HeLa parental cells and HeLa cells expressing Cx39, Cx43, Cx45, or Panx1 were exposed to an alkaline extracellular solution (pH 8.5) to increase HC activity. Under these conditions, dye uptake assays revealed high HC activity in all transfected cells but not in parental control cells. Previous studies have shown that Cx43 HCs, but not Cx39 and Panx1 HCs, allow the influx of extracellular Ca²⁺. Here, we also found that exposure of Cx45 transfectants to pH 8.5 activated HCs and allowed the influx of extracellular Ca²⁺. Only in cells expressing functional HCs permeable to Ca²⁺ did the elevated HC activity heighten the cytosolic Ca²⁺ concentration, which promoted lipid peroxidation and reduced cell viability. The effects were also abolished by the removal of extracellular divalent cations, suggesting that a Ca²⁺ influx that triggers downstream deleterious effects is required. Our findings identify Cx45 as a novel Ca²⁺-permeable HC, and they reveal that alkaline stress promotes Ca²⁺ entry via Cx43 and Cx45 HCs, which in turn leads to oxidative stress and cell death. Full article