Search Results (379)

Retinal neurovascular unit (RNVU) dysfunction underlies major blinding and neurodegenerative conditions including glaucoma, diabetic retinopathy (DR), age-related macular degeneration (AMD), retinal ischemia–reperfusion (RIR) injury, and Alzheimer’s disease (AD)-associated retinopathy. Within the RNVU, calcium ions coordinate neurotransmission, glial activation, vascular tone, and blood–retinal barrier maintenance, and calcium dysregulation is emerging as a unifying pathogenic hub across these conditions. Although upstream triggers differ, including mechanical stress in glaucoma, hyperglycemia in DR, oxidative damage in AMD, ischemic energy failure in RIR, and amyloid-β–driven endoplasmic reticulum stress in AD, all converge on disruption of intracellular calcium homeostasis, producing shared downstream consequences including excitotoxic injury of retinal ganglion cells (RGCs), Müller cell reactive gliosis, and pericyte hypercontraction. Broad-spectrum calcium channel blockade has shown limited clinical success, underscoring the need for cell-type-specific and pathway-selective approaches. This review therefore catalogs key interventional nodes, including transient receptor potential (TRP) channel antagonists, T-type calcium channel inhibitors, calcium/calmodulin-dependent protein kinase II (CaMKII) suppressors, and mitochondrial permeability transition pore (mPTP) inhibitors, and discusses how precision targeting of these pathways may restore RNVU homeostasis and open a therapeutic window into central nervous system (CNS) degenerative disorders. Full article

Pregabalin (PGB) exerts its therapeutic effects by binding to the α₂δ auxiliary subunits of voltage-gated calcium channels and modulates synaptic transmission in the brain. However, its influence on cerebellar parallel fiber–Purkinje cell (PF–PC) synaptic transmission remains unclear. In the present study, we investigated the effects of PGB on PF–PC synaptic transmission using whole-cell patch-clamp recording, glutamate fluorescence imaging, immunohistochemistry, co-immunoprecipitation, Western blotting, and pharmacological approaches. Micro-application of PGB to the cerebellar molecular layer induced a concentration-dependent inhibition of PF–PC excitatory postsynaptic currents (EPSCs), accompanied by an increased paired-pulse ratio. The inhibitory effect of PGB on PF–PC EPSCs was abolished by extracellular blockade of N-methyl-D-aspartate receptors (NMDAR) or their GluN2A subtype, as well as by disruption of α₂δ-1–NMDAR complexes, but not by intracellular NMDAR inhibition. Glutamate sensor imaging further showed that PGB markedly reduced the fluorescence intensity of glutamate release evoked by PF stimulation. In the presence of tetrodotoxin (TTX) and a gamma-aminobutyric acid type A (GABAA) receptor antagonist, PGB reduced the frequency of miniature excitatory postsynaptic currents (mEPSCs) without affecting their amplitude. The PGB-induced reduction in mEPSC frequency was fully abolished by extracellular blockade of GluN2A-containing NMDARs or disruption of α₂δ-1–NMDAR complexes. Similarly, the inhibitory effects of PGB on PF–PC EPSCs and mEPSCs were eliminated by extracellular PKA inhibition, but not by intracellular protein kinase A (PKA) inhibition. Western blot analysis showed that PGB significantly increased PKA phosphorylation in the molecular layer of the cerebellar cortex. Immunoreactivity for GluN2A and α₂δ-1 subunits was colocalized within the molecular layer and abundantly distributed around the dendrites and somata of PCs. Co-immunoprecipitation further verified that α₂δ-1 was co-precipitated with GluN1 in cerebellar molecular layer tissue samples. The results indicate that PGB depresses glutamate release from parallel-fiber terminals in the mouse cerebellar cortex through the presynaptic α₂δ-1-coupled GluN2A-containing NMDAR/PKA signaling pathway, thereby attenuating PF–PC synaptic transmission. Full article

Autophagy and apoptosis are two evolutionarily conserved catabolic processes that play important roles in maintaining cellular homeostasis and in determining cell fate when cells are exposed to various stresses in vivo. The interaction between autophagy and apoptosis has been studied extensively in cancer research, and it has been shown to affect cancer initiation and tumor formation, disease progression, therapeutic resistance, and overall survival. Autophagy typically functions as a cytoprotective mechanism in cancer cells subjected to metabolic, hypoxic, or therapeutic stress, whereas apoptosis primarily functions as an intrinsic programmed cell death pathway. While apoptosis and autophagy function as distinct pathways, there is significant molecular crosstalk, allowing cells to modulate their behavior from survival to death depending on the severity and duration of exposure to a given stressor and the cellular environment. This review examines the molecular landscape of the autophagy–apoptosis interplay in cancers, with special attention paid to the major signaling pathways involved and their biological outcomes in oncology. We examine the molecular mechanisms and signal transduction pathways involved in the crosstalk between autophagy and apoptosis in cancer. In particular, we focus on several key proteins that regulate this crosstalk, including kinases, caspases, heat shock proteins and transcription factors. Furthermore, we describe the major signal transduction pathways that regulate this crosstalk, including the PI3K/Akt/mTOR, MAPK, unfolded protein response, oxidative stress, and calcium signaling pathways. Additionally, we discussed how dysregulation of these pathways contributes to cancer progression and treatment resistance. Finally, we summarized the use of currently available therapeutic agents targeting the crosstalk between autophagy and apoptosis, including FDA-approved drugs and natural products, with the potential to enhance the effectiveness of anticancer treatments. A better understanding of this complex process will allow the development of new, precision-based, combination cancer therapies. Full article

Intracellular calcium (Ca²⁺) signaling is a central regulator of corticogenesis, governing haveneural stem cell behavior, fate transitions, neuronal migration, and circuit assembly. Beyond its canonical role as a second messenger, Ca²⁺ shapes cytoskeletal organization by modulating microtubule dynamics essential for mitotic spindle function, radial glial scaffold, nucleokinesis, and neurite extension. This review synthesizes evidence from in vivo, ex vivo, and in vitro studies to delineate Ca²⁺-dependent pathways and Ca²⁺-binding proteins that couple, within restricted Ca²⁺ microdomains in space and time, to microtubule regulation during mammalian cortical development. We highlight mechanistic nodes involving calmodulin, Ca²⁺/calmodulin-dependent kinases (CaMKs), S100 proteins, cadherins/protocadherins, centrins (CENs), and Ca²⁺ sensors such as STIM1 and calneurons, which collectively coordinate spindle orientation, progenitor division modes, radial migration, and neurite outgrowth. Finally, we discuss how perturbations in Ca²⁺-controlled cytoskeletal programs may contribute to abnormal cortical cytoarchitecture and neurodevelopmental disease. By integrating Ca²⁺ microdomain transients with microtubule control modules, this review provides a unified framework for understanding how Ca²⁺ orchestrates key cellular events during mammalian corticogenesis and propose that Ca²⁺ oscillatory codes are translated into direct or indirect microtubule/cytoskeletal remodeling transitions that determine neural stem cell fate, migration, and maturation, to accurately establish cortical architecture and function. Full article

Cadmium (Cd) is a typical heavy metal pollutant in aquatic environments. It enters fish through the gills, digestive tract, and body surface, and accumulates mainly in the liver and kidneys, with species- and tissue-specific distribution. Cadmium triggers apoptosis by inducing oxidative stress, calcium imbalance, and DNA damage. These signals are integrated and amplified by the mitogen-activated protein kinase (MAPK), nuclear factor kappa B (NF-κB), phosphatidylinositol 3-kinase (PI3K)/AKT, and nuclear factor erythroid 2-related factor 2 (Nrf2) pathways, ultimately activating three downstream apoptotic execution pathways: the death receptor, mitochondrial, and endoplasmic reticulum stress pathways. These three pathways form an interactive network through molecular nodes such as BH3 interacting domain death agonist (Bid), Ca²⁺, c-Jun N-terminal kinase (JNK), and C/EBP homologous protein (CHOP), synergistically amplifying the apoptotic effect, with the mitochondrial pathway playing a central role. Cadmium-induced apoptosis is dose-dependent: low concentrations activate protective responses, whereas high concentrations strongly promote apoptosis. Current research gaps remain regarding dynamic pathway crosstalk, chronic low-dose effects, species differences, and fish-specific apoptotic molecules (e.g., caspase-12 homologs). Future studies should focus on constructing multidimensional response maps, clarifying pathway activation thresholds and interaction contributions, and developing composite protective strategies based on Nrf2 activators, metal chelators, and antioxidants, thereby promoting translation into ecological risk assessment and aquaculture pollution control. 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

Neurogranin (Ng) is a postsynaptic calmodulin-binding protein highly enriched in forebrain neurons and widely implicated in synaptic plasticity. However, whether Ng contributes more broadly to neuronal network maturation and cellular homeostasis remains unclear. Here, we examined the consequences of silencing or restoring Ng to adult physiological levels in primary hippocampal neurons. Ng expression promoted dendritic expansion, increased synaptic number, and shifted the axon initial segment toward the soma, consistent with structural adaptations to enhanced connectivity. Calcium (Ca²⁺) imaging revealed a marked increase in spontaneous neuronal activity and network synchronization, which was confirmed by electrophysiological recordings showing enhanced burst firing and spike synchrony. At the molecular level, Ng altered Ca²⁺/calmodulin (CaM) signaling by increasing total CaM levels, reducing Ca²⁺/CaM-dependent protein kinase II (CaMKII) abundance while increasing its relative autophosphorylation, and downscaling specific ionotropic glutamate receptors. Despite elevated network activity, Ng expression enhanced neuronal metabolic competence and viability, reduced cellular stress signaling and induced modest caspase-3 activation without engagement of apoptotic pathways. Together, these results indicate that Ng promotes neuronal maturation and coordinated network activity while engaging compensatory mechanisms that preserve excitatory balance and neuronal resilience. Our findings identify Ng as a molecular integrator linking Ca²⁺/CaM signaling with the structural and functional maturation of neuronal networks. Full article

Background: We investigated whether a water extract of Lilii bulbus (Lilium lancifolium Thunberg; WELB) could modulate inhibitory synaptic organization in a mouse model of pentylenetetrazol (PTZ)-induced kindling. Methods: Starting 14 days prior to the initial PTZ challenge, WELB (500 mg/kg) was delivered via oral gavage once daily. This treatment regimen was maintained for a total of 40 days, spanning the entire period until the animals reached the fully kindled state. Results: Behavioral assessments revealed that WELB treatment significantly reduced seizure severity and Racine scores, prolonged the latency to clonic seizures, and shortened seizure duration, demonstrating potent anticonvulsant activity. Two-photon calcium imaging further showed that WELB markedly suppressed PTZ-induced neuronal hyperexcitability in the posterior parietal cortex, accompanied by decreased expression of neuronal activation markers, including c-fos, phosphorylated-calcium/calmodulin-dependent protein kinase IIα (p-CaMKIIα), and N-methyl-D-aspartate receptor 1 (NR1). In the hippocampus, WELB modulated the expression of GABAergic interneuron markers [glutamate decarboxylase 67 (GAD67), vesicular GABA transporter (VGAT), parvalbumin (PV), somatostatin (SOM)] and upregulated GABAergic gene transcripts [GABA-A receptor α1 subunit (Gabra1), GABA-A receptor α2 subunit (Gabra2), GABA transporter 1 (Gat1), GABA transporter 3 (Gat3), PV, SOM, cholecystokinin (CCK)] that were downregulated by PTZ kindling. Moreover, WELB enhanced the expression of GABAergic synaptic organization-related proteins (gephyrin, collybistin, neurexin-1β, neuroligin-2, and neuropilin-2), indicating its regulatory effect on inhibitory synaptic integrity. Conclusions: Collectively, these findings suggest that WELB may exert its anticonvulsant effects by functionally remodeling GABAergic synaptic organization-related factors, thereby restoring inhibitory circuit integrity and providing a mechanism-based therapeutic strategy for epilepsy and seizure-related neurological disorders. Full article

Bumped kinase inhibitors (BKIs) have demonstrated safety and promising efficacy against various apicomplexan pathogens both in vitro and in vivo, but do not act parasiticidal in vitro. In the closely related cyst-forming coccidians Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti, treatments with BKI-1708 induce the conversion of intracellular tachyzoites into atypical multinucleated complexes named “baryzoites”. In this study, we comparatively assessed tachyzoites and baryzoites of all three species with respect to ultrastructure, differential antigen expression by immunofluorescence, and overall differential protein expression by MS-proteomics. TEM demonstrated common, but also distinguishing, structural features in baryzoites of the three species. They contained newly formed zoites, unable to complete cytokinesis, and thus they were trapped intracellularly. An electron-dense cyst wall-like structure was found only in T. gondii baryzoites. Species-specific differences in antigen expression were observed by immunofluorescence. Comparative proteomic analysis of baryzoites versus tachyzoites revealed a downregulation of ribosomal proteins, proteins associated with secretory organelles, as well as of transcription and translation factors in baryzoites across all species. Bradyzoite-specific markers were upregulated only in T. gondii baryzoites. Two alveolin-domain filament proteins and a hypothetical protein (TGME49_236950, NCLIV_050850, BESB_060040) were detected at higher abundance in all three species. Thus, baryzoites exhibit distinct phenotypic and proteomic profiles, with ambiguous expression of tachyzoite and bradyzoite antigens, suggesting a reversible response to stress rather than progression into a fully differentiated form. Full article

Intervertebral disc degeneration is characterized by inflammation, extracellular matrix breakdown, and neurovascular ingrowth, processes that contribute to discogenic, chronic back pain. The transient receptor potential canonical 6 (TRPC6) channel is a calcium-permeable ion channel implicated in inflammation and pain signaling in multiple tissues; however, its functional role in human disc cells remain unknown. Here, we investigated the expression, activation, and downstream consequences of TRPC6 activation using Hyp9, a pharmacological activator of TRPC6. TRPC6 transcripts were consistently detected across all donors examined (n = 17). Functional TRPC6 activation induced a rapid, dose-dependent calcium (Ca²⁺) influx across 0.5–100 µM Hyp9. TRPC6 activation did not reduce metabolic activity or increase cytotoxicity at concentrations commonly used for in vitro TRPC6 activation. Mechanistically, TRPC6 activation induced mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) pathways, as demonstrated by increased phosphorylation of p38 and extracellular signal-regulated kinase (ERK), degradation of the inhibitor of κB-alpha (IκB-α), and increased nuclear translocation of the NF-κB p65 subunit. Downstream of these early signaling events, TRPC6 activation elicited a robust inflammatory and catabolic response with upregulation of IL-6, IL-8, COX-2, MMP-1, MMP-3, NGF, and VEGF, with corresponding increases in protein secretion. These findings identify TRPC6 as an important signaling node linking calcium influx to inflammatory, catabolic, and neuro- and angiogenesis-associated pathways in disc cells, highlighting TRPC6 as a potential therapeutic target in degenerative disc disease. Full article

Background/Objectives: Humans have at least 26 bitter taste receptors (T2Rs), and among these, bitter taste receptor 14 (T2R14) is highly expressed in both oral and extraoral tissues. Over 100 bitter ligands can activate T2R14, including hormones, vitamins, plant compounds, and peptides. Previous studies suggest that bitter tastants such as quinine and caffeine can inhibit G protein-coupled receptor kinases (GRKs) and delay T2R signal termination. Our earlier research showed that peptides from alcalase and chymotrypsin hydrolysates of beef proteins inhibited quinine-dependent calcium release through T2R4, with AGDDAPRAVF and ETSARHL showing the greatest effectiveness. However, the effect of these antagonistic peptides on other T2Rs, such as T2R14 signaling, remains unknown. This study aimed to evaluate the ability of these beef protein-derived peptides to activate or inhibit T2R14 signaling and the involvement of GRK2 in signal termination. Methods and Results: Our results indicate that the above two antagonist peptides significantly inhibit T2R14 activity. Furthermore, GRK2 knockout in HEK cells stably expressing T2R14 decreases intracellular calcium release, as measured by the area under the curve (AUC), and also delays the fall time (indication of desensitization) of the calcium response when exposed to the T2R14 agonist diphenhydramine (DPH) or beef protein-derived agonist peptide TMTL. Next, we measured the effects of these ligands on cAMP accumulation, and our results suggest no significant change in cAMP levels upon treatment with beef protein-derived peptides. Conclusions: Thus, this study showed that beef protein-derived peptides can function as both T2R inhibitors and mediate T2R14 desensitization through GRK2 signaling. These antagonistic food protein-derived peptides inform strategies to enhance nutrition, such as promoting healthier food choices by reducing bitterness and thereby improving the palatability of health-promoting bitter foods, such as fruit and vegetable extracts, as well as bitter medications. Full article

Myocardial ischemia–reperfusion injury remains a major unresolved challenge in cardiovascular medicine. Although timely restoration of blood flow is essential to limit ischemic damage, reperfusion triggers a complex network of maladaptive biological responses, including oxidative stress, calcium overload, mitochondrial dysfunction, metabolic impairment, and sterile inflammation. These processes converge on cardiomyocyte death, adverse ventricular remodeling, and long-term functional deterioration. Mesenchymal stem cells have been widely investigated as cardioprotective agents; however, accumulating evidence indicates that their beneficial effects are predominantly mediated by paracrine mechanisms. Among these, extracellular vesicles released by mesenchymal stem cells have emerged as key biological effectors. Experimental studies demonstrate that mesenchymal stem cell–derived extracellular vesicles modulate multiple signaling pathways involved in ischemia–reperfusion injury, including activation of the phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB) axis, regulation of signal transducer and activator of transcription 3 (STAT3) signaling in a cell-specific manner, suppression of nuclear factor kappa B (NF-κB)-driven inflammatory responses, and stabilization of hypoxia-inducible factor-1α (HIF-1α)–dependent adaptive programs. At the subcellular level, these vesicles preserve mitochondrial structure and function, support energy metabolism, regulate mitophagy, and limit oxidative damage. Their molecular cargo, comprising regulatory microRNAs, metabolic enzymes, and stress-response proteins, enables coordinated modulation of survival, inflammatory, and reparative pathways rather than single-target effects. This review synthesizes current experimental evidence on the mechanistic basis of mesenchymal stem cell–derived extracellular vesicle–mediated cardioprotection and discusses their potential as cell-free, mechanism-based therapeutic strategies to limit myocardial ischemia–reperfusion injury. Full article

(1) Background: The increasing environmental concentration of polystyrene nanoplastics (PS-NPs) may pose a risk of human exposure and health threats. Previous studies have demonstrated that exposure to PS-NPs poses a threat to neural synaptic plasticity, yet the underlying mechanisms remain unclear. (2) Methods: Hippocampal astrocytes and neurons were co-cultured, exposed to PS-NPs at concentrations of 10, 50, and 100 μg/mL, and cytotoxicity was assessed. We investigated PS-NP-induced impairment of synaptic plasticity by regulating the brain-derived neurotrophic factor (BDNF). (3) Results: Calmodulin-dependent protein kinase II (CaMKII) is a central molecular organizer of synaptic plasticity, learning, and memory, and its activity is intrinsically linked to intracellular calcium ion concentration. Our research indicates that PS-NPs may interfere with calcium ion signaling and CaMKIIα activity, thereby reducing CaMKIIα activity. This subsequently downregulates the expression of cAMP response element-binding protein (CREB), modulates BDNF expression, and impacts synaptic plasticity. (4) Conclusions: In summary, this study primarily focused on the effects of PS-NPs exposure on hippocampal synaptic plasticity. Full article

Calcium-dependent protein kinases (CDPKs) are crucial calcium sensors in plants that perceive transient calcium fluctuations. Structurally, CDPKs contain an integrated serine/threonine protein kinase domain, which enables them to function as protein kinases. Through phosphorylation of downstream target proteins, CDPKs transduce specific calcium-encoded signals to regulate diverse physiological processes. As pivotal signaling molecules, CDPKs function as critical regulators in plant growth, development, and stress responses. This review comprehensively summarizes the structure of CDPKs and their signal transduction mechanisms. It further elaborates on the multifaceted functions of CDPKs across diverse plant species, encompassing their regulatory roles in developmental processes, responses to abiotic and biotic stresses, and intricate interactions with phytohormone signaling pathways. Full article

Bitter gourd (Momordica charantia L.) is widely consumed worldwide due to its unique flavor and medicinal value. In subtropical regions, low spring temperatures limit bitter gourd growth, leading to plant mortality and yield loss. Thus, elucidating the mechanisms of cold tolerance in bitter gourd could facilitate the development of cold-resistant cultivars via genetic engineering or molecular breeding. In this study, a cold-tolerant (CT) and a cold-sensitive (CS) inbred line of bitter gourd were used to investigate proteomic differences under cold stress. Before cold stress, 504 differentially accumulated proteins (DAPs) were identified, with 123 up-accumulated in CT plants compared to CS plants. Upon exposure to cold stress, these numbers changed to 388 DAPs (259 up-accumulated in CT) at 6 h and further to 649 DAPs (415 up-accumulated in CT) at 24 h. K-means cluster analysis identified 65 cold-stress response proteins that may contribute to cold tolerance in CT plants, including evm.TU.chr4.3733 (Proline dehydrogenase 1), evm.TU.chr10.115 (Delta(1)-pyrroline-2-carboxylate reductase), and evm.TU.chr10.815 (Calcium-dependent protein kinase 3). Glucose and starch levels remained stable in both CS and CT plants during cold stress, and the baseline concentration of glucose was consistently and significantly higher in CT plants than in CS plants. Before cold stress, proline content was similar in both CT and CS plants. Following 6 h of cold stress, CS plants accumulated significantly higher proline levels than CT plants. This trend, however, reversed after 24 h, with proline content becoming significantly lower in CS plants. Differential protein accumulation between CT and CS plants under cold stress reflects their distinct responses, with core DAPs serving as key functional determinants of enhanced cold tolerance in the CT genotype. This study revealed important proteomic data underlying the cold stress response in bitter gourd. Full article