Search Results (1,380)

The small heat shock protein HSPB1 is a ubiquitously expressed mechanoresponsive chaperone essential for cytoskeletal remodeling under mechanical load. Mutations in HSPB1, including S135F, cause Charcot-Marie-Tooth (CMT) peripheral neuropathy, yet the mechanisms underlying the selective vulnerability of peripheral nerves remain enigmatic. Here we demonstrate that substrate stiffness is a critical determinant of HSPB1^S135F-mediated neurodegeneration. Using stiffness-tunable polydimethylsiloxane (PDMS) substrates (1 kPa, 10 kPa, 2 MPa) and uniaxial cyclic stretch, we show that primary dorsal root ganglia (DRG) neurons and SH-SY5Y cells expressing HSPB1^S135F exhibit profound deficits in mechanoadaptation. On compliant substrates (10 kPa), HSPB1^S135F causes stretch-induced axon fragmentation and neuronal death, whereas HSPB1^WT confers robust neuroprotection. HSPB1^S135F also disrupts stiffness-directed neuritogenesis in differentiated SH-SY5Y cells: HSPB1^WT-expressing cells show optimal axonal outgrowth and βIII-tubulin expression on 10 kPa substrates mimicking muscle tissue stiffness, while HSPB1^S135F mutants display disorganized focal adhesions and complete differentiation failure. Mechanistically, we uncover that HSPB1^S135F dysregulates stage-specific transglutaminase (TGase) expression—insufficient TGase during early neuritogenesis impairs filopodia stabilization, whereas aberrant TGase persistence at late stages constrains axon extension. Our findings establish HSPB1 as a biomechanical sensor that integrates ECM stiffness signals to coordinate peripheral nerve regeneration, and identify defective mechanoadaptation as a previously unrecognized pathomechanism in CMT. These results open new avenues for stiffness-targeted therapeutic strategies in peripheral neuropathy. Full article

Species of Talaromyces affect human societies in many different ways. Infrageneric classifications of the genus at series level had been established in only two sections, Subinflati and Trachyspermi. In this study, phylogenies of Talaromyces were reconstructed section by section based on separate or concatenated multi-locus datasets: beta-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second-largest subunit (RPB2). Fifty series belonging to nine sections were accordingly recognized, i.e., one in sections Brunneospori and Tenues, two in sections Bacillispori and Helici, three in sect. Subinflati, four in sect. Purpurei, five in sections Islandici and Trachyspermi, and 27 in the speciose section Talaromyces. Among them, forty series were newly established. Three new species were determined phylogenetically and morphologically, i.e., T. fujianensis sp. nov. in sect. Islandici, T. heilongjiangensis sp. nov. in sect. Talaromyces and T. tapisciae sp. nov. in sect. Subinflati. Additionally, three new Chinese records were noted: T. angelicae, T. gautengensis and T. rogersiae. The findings of new species and new records reveal the high diversity of the genus in China. The updated taxonomy of Talaromyces at series level will facilitate a more accurate species identification by means of phylogenetic analysis at a smaller scale, and benefit future studies involving this group of fungi. Full article

Beauveria bassiana (Balsamo-Crivelli) Vuillemin can colonize plant tissues as an endophyte, promoting plant growth and defense against pathogens and insect herbivory. Understanding the endophytic behavior of native isolates is important for developing pest management strategies in maize, a crop affected by Spodoptera frugiperda (J. E. Smith). This study aimed to genetically characterize a Mexican B. bassiana isolate (Bb-IIAF1-24) collected in Los Reyes, Michoacán, using the β-tubulin gene. The phylogenetic relationships showed that this isolate formed a well-supported clade with other B. bassiana isolates from different countries; however, a low divergence among them was observed. In a second part of this study, the influence of foliar and soil inoculation (1 × 10⁸ conidia mL⁻¹) of Bb-IIAF1-24 isolate on endophytic colonization in maize plants, as well as the effects on plant growth and herbivory by S. frugiperda were evaluated. This fungus was detected in roots, stems, and leaves, but no significant differences were found between root and stem colonization or between foliar and soil inoculation methods. Beauveria bassiana treatment resulted in increased stem diameter in plants when applied to soil compared to foliar application and the control. In contrast, plants subjected to foliar application were significantly taller than those receiving soil application or the control plants. Plants from both application methods experienced lower leaf damage compared to the control. These findings demonstrate the potential of the Bb-IIAF1-24 isolate as an endophytic fungus to promote maize growth and reduce herbivory by S. frugiperda. Full article

Microtubules contain ordered aromatic amino acid networks whose optical excitations have been proposed to support non-trivial energy-transfer dynamics. Here, we examined whether bound tryptamine ligands can perturb the excitonic structure of the tubulin tryptophan network. A virtual screen of 294 tryptamines was performed across seven known binding regions of the tubulin heterodimer using AutoDock Vina 1.2.6. From this screen, top-ranked tryptamine ligands were carried forward for excited-state analysis. Geometry optimization and time-dependent density functional theory (TD-DFT) calculations were used to obtain vertical excitation energies and transition dipole moments for the ligand-bound states in the ultraviolet range. These ligand properties were then incorporated into a tight-binding Hamiltonian describing the tubulin tryptophan excitation network in order to evaluate changes in exciton energies and eigenvector delocalization. The calculations indicate that tryptamine binding can modify the excitonic landscape of tubulin in a ligand-dependent manner, with the magnitude of the perturbation governed by excitation wavelength, transition dipole strength, and spatial orientation relative to the intrinsic tryptophan network. These results show that substituted tryptamines differ in how they perturb the modeled tubulin tryptophan excitonic manifold, but they do not by themselves establish experimentally resolvable modulation of tubulin or microtubule photophysics. The present work should therefore be interpreted as a first-pass computational screening framework for prioritizing ligands and defining future experimental tests. Full article

The voltage-dependent anion channel (VDAC) is the primary conduit for ion and metabolite transport across the mitochondrial outer membrane. Positioned at the interface between the cytosol and the mitochondrial compartment, VDAC is uniquely accessible to proteins on both sides of the membrane, making it an interaction hub whose biophysical properties and signaling functions are shaped by protein complexation in addition to its intrinsic pore specialization. Mammals express three isoforms—VDAC1, VDAC2, and VDAC3—sharing a conserved β-barrel scaffold with about 70% identity. However, minor differences in the sequence lead to drastic changes in VDAC isoform affinity with other proteins. Here, we review the molecular mechanisms and physiological consequences of VDAC complexation with a set of well-characterized partners: hexokinase, dimeric tubulin, α-synuclein, mitochondria-associated membrane proteins, B-cell lymphoma 2 (BCL-2) family proteins, and the translocase of the outer membrane (TOM) protein import complex. For each complex, we evaluate the available structural, biophysical, and genetic evidence for isoform specificity, highlight where mechanistic understanding is most advanced, and identify open questions. A consistent principle emerges across all complexes: functionally nonredundant isoform contributions are primarily governed by differential partner affinity and complexation, rather than by differences in pore architecture alone. This framework has direct implications for mitochondria-associated pathologies, including cancer, cardiovascular disease, and neurodegeneration, as well as for the rational design of VDAC-targeting therapeutics. Full article

Grapevine black-foot disease is a destructive trunk disease with a complex pathogen composition that often involves mixed and latent infections, making timely field diagnosis challenging. To improve rapid field detection, we developed a rapid, sensitive, and low instrument-dependent nucleic acid assay. The assay integrates recombinase polymerase amplification (RPA) and clustered regularly interspaced short palindromic repeats (CRISPR)–Cas12a for the detection of Ilyonectria and Dactylonectria, two genera associated with grapevine black-foot disease. Conserved regions of the histone H3 and β-tubulin genes were selected for the design of specific RPA primers and corresponding CRISPR RNAs (crRNAs) for Ilyonectria and Dactylonectria, respectively. A workflow integrating RPA, Cas12a-mediated recognition, and lateral flow assay (LFA)-based visualization was established. The reaction conditions were optimized to enhance amplification efficiency and Cas12a recognition stability. Specificity was evaluated using DNA from target and non-target fungi, and sensitivity was determined using serially diluted templates. Under optimized conditions, the assay detected Ilyonectria DNA at concentrations as low as 3.6 ng/μL within 1 h at 39 °C. For Dactylonectria, the detection limit reached 80 fg/μL within 50 min at 41 °C. No cross-reactivity was observed. The LFA strips exhibited positive and negative bands within minutes, enabling rapid visual interpretation. This RPA-CRISPR/Cas12a-LFA system provides a rapid, visually interpretable approach for detecting selected grapevine black-foot disease-associated species in China. The workflow reduces the requirement for specialized thermocycling and fluorescence detection equipment during amplification and readout, following DNA extraction. Full article

Background: Benzimidazole (BZ) resistance in the gastrointestinal nematode Haemonchus contortus is a major constraint to sheep production worldwide. However, data on the prevalence and molecular mechanisms of resistance in Yili Prefecture, Xinjiang—a key livestock region in Northwestern China—remain limited. This study aimed to determine the frequency of BZ resistance-associated single nucleotide polymorphisms (SNPs) in H. contortus populations from Zhaosu and Tekesi counties. Methods: Adult male worms (n = 150) were collected from naturally infected sheep at local abattoirs. Species identity was confirmed morphologically by sequencing the internal transcribed spacer 2 (ITS-2) region. A 385 bp fragment of the isotype-1 β-tubulin gene was amplified and sequenced to detect SNPs at codons 167 (F167Y), 198 (E198A), and 200 (F200Y). Results: The F167Y mutation was absent in all individuals. In contrast, the E198A mutation occurred at exceptionally high frequencies, with resistant allele frequencies (RAF) of 64.7% in Zhaosu and 52.7% in Tekesi. The F200Y mutation showed clear geographical variation: it remained low in Zhaosu (RAF = 9.3%) but was substantially higher in Tekesi (RAF = 33.3%). Haplotype analysis revealed that resistance in Zhaosu was driven primarily by the E198A mutation, whereas the Tekesi population exhibited complex patterns of co-selection of both E198A and F200Y, with a high proportion of double-heterozygous individuals (29.3%). Conclusions: This study provides comprehensive molecular evidence of severe BZ resistance in H. contortus populations from Zhaosu and Tekesi counties, Yili Prefecture. The marked predominance of the E198A mutation, together with the emergence of multi-locus resistance in Tekesi, indicates a rapid escalation of resistance beyond historical levels. These findings suggest that benzimidazoles are likely ineffective in this region and highlight the urgent need to revise local parasite control strategies. Full article

B cell activation requires the formation of an immune synapse (IS), where coordinated cytoskeletal remodeling and organelle dynamics enable antigen extraction and presentation. While mitochondria are known to regulate cellular metabolism during activation, their role in IS function remains poorly understood. Here, we investigated how mitochondrial dynamics influence antigen processing and presentation in B cells. We show that B cell receptor (BCR) engagement induces rapid phosphorylation of the mitochondrial fission GTPase Drp1 at Ser616. Treatment with mdivi-1, a compound used to perturb Drp1-associated mitochondrial fission that can also affect mitochondrial complex I activity, altered mitochondrial morphology, reduced mitochondrial activity, and decreased their stable accumulation at the synapse. This was accompanied by increased tubulin acetylation, lysosome retention near the MTOC, and reduced delivery to the synaptic membrane. Accordingly, lysosome fusion, antigen extraction, and presentation to T cells were significantly diminished in mdivi-1-treated B cells. Together, our findings suggest that mdivi-1-sensitive mitochondrial fission and activity are associated with mitochondrial positioning, lysosomal trafficking, and exocytosis at the B cell immune synapse, supporting a model in which mitochondrial dynamics contribute to efficient antigen extraction and presentation. Full article

Diabetic neuropathy is typically diagnosed with distal sensory and nerve conduction abnormalities. These symptoms may reflect earlier disturbances of axonal maintenance. This review examines axonal transport and cytoskeletal failure as convergent cellular mechanisms of diabetic axonopathy. Long peripheral axons are particularly vulnerable to damage because their integrity depends on continuous communication between the neuronal soma and distal terminals. This process involves the continuous renewal of cytoskeletal and functional proteins and the involvement of organelles such as mitochondria. Diabetes in experimental models disrupts this system at several levels. It slows cargo transport. The supply of neurofilaments, tubulin and retrograde signaling is reduced, and regenerative growth after injury is weakened. Carbonyl stress and AGEs cause modifications of neural proteins, the extracellular matrix, vascular barriers, and the excitability of sensory neurons. RAGE ligands, including AGEs and the proteins HMGB1 and S100, link the diabetic tissue environment to redox and inflammatory signaling. This occurs in neural and glial compartments, as well as in vascular tissue and the immune system. RAGE interacts with DIAPH1 to activate GTPase signaling and remodel the cytoskeleton. The RAGE–DIAPH1 interaction provides a plausible route from diabetic ligand accumulation to cytoskeletal remodeling. These observations provide a mechanistic context for axonal transport, although not all represent direct measurements of cargo movement. Direct evidence for transport impairment comes mainly from experimental studies showing altered slow cytoskeletal transport, impaired retrograde signaling, and weakened regenerative responses. This work highlights the possibility of developing therapies that go beyond symptomatic relief. Verifying the effectiveness of interventions in protecting axonal transport and nerve fiber integrity in diabetic neuropathy may be therapeutically beneficial. Full article

Background/Objectives: Microtubule-targeting agents represent a pillar of cancer chemotherapy; however, their clinical utility is constrained by significant toxicity, pharmacokinetic instability, and susceptibility to multidrug resistance transporters. This study aimed to explore the impact of replacing substituted phenyl rings with a naphthalene moiety in sulfonamide-based colchicine-site ligands, with the goal of identifying new antiproliferative candidates with improved profiles. Methods: We designed, synthesized, and evaluated a library of 35 naphthalene sulfonamides bearing varied aryl groups and sulfonamide nitrogen substituents. We assessed the antiproliferative activity against multiple cancer cell lines. Mechanistic studies, including fluorescence microscopy, cell cycle analysis, and cell death assays, were performed to evaluate the effect of these compounds on microtubule polymerization dynamics and cell fate. Molecular docking and in silico pharmacokinetic profiling were carried out to support the proposed binding mode at the colchicine site and to assess drug-likeness. Results: Exclusively, compounds bearing a trimethoxyphenyl group showed antiproliferative activity in the submicromolar range, thus identifying it as a structural requirement. The most potent compound (2) reached double-digit nanomolar IC₅₀ values (67–104 nM) across multiple cancer cell lines. Microscopy confirmed intracellular disruption of microtubule polymerization. Unlike colchicine, these compounds did not induce canonical mitotic arrest but instead triggered apoptotic cell death. In silico analyses supported binding at the colchicine site and revealed favorable predicted pharmacokinetic properties. Conclusions: The naphthalene sulfonamides described herein demonstrate potent antiproliferative activity through a distinct mechanism compared to colchicine, and their favorable in silico profiles position them as promising candidates for further development as antitumor agents. Full article

Background/Objectives: Chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with epithelial remodeling, impaired mucociliary clearance, and altered nitric oxide (NO) metabolism. However, cell type-specific mechanisms underlying epithelial NO signaling remain poorly understood. This study investigated NO-related signaling in differentiated human sinonasal epithelial cells. Methods: Human sinonasal tissues were obtained from patients with CRSwNP (n = 20) and control subjects (n = 20). Air–liquid interface (ALI) cultures were established from donor-derived epithelial cells. Ciliated and non-ciliated cells were identified by immunostaining for acetylated α-tubulin and BCAM. Expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) was analyzed by quantitative RT-PCR. Intracellular NO-related fluorescence signals were evaluated using DAF-FM fluorescence imaging. Results: CRSwNP tissues exhibited significantly increased iNOS expression and elevated iNOS/eNOS ratios, whereas eNOS expression did not differ significantly from that in controls. ALI cultures reproduced differentiated sinonasal epithelium containing both ciliated and non-ciliated cell populations. DAF-FM fluorescence signals were significantly higher in ciliated cells than in non-ciliated cells (80.3 ± 25.3 vs. 49.3 ± 21.1). Non-selective NOS inhibition markedly reduced fluorescence signals in both cell types, whereas selective iNOS inhibition reduced but did not abolish signals in ciliated cells. Conclusions: NO-related signaling appears to differ among epithelial cell subtypes. Persistence of fluorescence signals after selective iNOS inhibition suggests a contribution of constitutive NOS activity in ciliated cells, whereas non-ciliated cells appear to rely more heavily on iNOS-dependent pathways. These findings support the hypothesis that altered epithelial NO signaling contributes to epithelial dysfunction and impaired mucociliary homeostasis in CRSwNP. Full article

Aspergillus spp. are common environmental molds worldwide and mostly cause infections in immunocompromised individuals. We have previously shown that black aspergilli (Aspergillus section Nigri) isolates are the most common aspergilli in indoor and outdoor hospital environments in Kuwait. This study reports on the relative prevalence of different Aspergillus section Nigri complex species among clinical isolates and their susceptibility to antifungal drugs. Black aspergilli isolated from clinical (n = 34) and environmental (n = 2) sources were studied. The isolates were initially identified as Aspergillus section Nigri complex members based on morphological characteristics. Species-specific identification was carried out by PCR-sequencing of the β-tubulin gene fragment and sequence comparisons with the GenBank database. The phylogenetic analysis was performed by using the Maximum Likelihood method in MEGA (version 11) software. Antifungal susceptibility testing was performed by Etest. The phylogenetic analysis based on β-tubulin gene sequences identified only three species: A. niger sensu stricto (A. niger) (n = 26), A. tubingensis (n = 7), and A. luchuensis (n = 1) among 34 clinical Aspergillus section Nigri isolates in Kuwait. All seven otomycoses cases were due to A. niger. The two environmental isolates were identified as A. niger and A. tubingensis. All isolates appeared susceptible to all five (amphotericin B, itraconazole, voriconazole, posaconazole, and caspofungin) antifungal drugs tested. In conclusion, our study shows that A. niger predominates among phenotypically identified clinical isolates of the Aspergillus section Nigri complex, and that A. niger is also the main agent in otomycosis cases in Kuwait. The detection of only three species within the Aspergillus section Nigri complex in Kuwait could be due to the limited number (n = 34) of clinical isolates analyzed in this study. Full article

Background: Actinic keratoses are common keratinocytic precursor lesions arising within chronically ultraviolet-damaged skin and are associated with an increased risk of progression to cutaneous squamous cell carcinoma. The concept of field cancerization has shifted therapeutic strategies from the treatment of isolated visible lesions toward broader field-directed approaches targeting both clinical and subclinical disease. Methods: This narrative review summarizes the rationale, mechanisms of action, efficacy profile, tolerability, and practical limitations of currently available field-directed therapies for actinic keratosis, including 5-fluorouracil, imiquimod, diclofenac, photodynamic therapy, and tirbanibulin. Based on their distinct biological targets, we propose a mechanism-based framework for sequential treatment strategies. Results: Available therapies act through partially non-overlapping mechanisms, including cytotoxic activity, immune activation, cyclooxygenase-2 inhibition, photodynamic oxidative damage, and tubulin/Src pathway inhibition. These complementary effects provide a biological rationale for sequential regimens aimed at addressing the heterogeneity of field cancerization. However, direct clinical evidence supporting specific treatment sequences remains limited, and proposed regimens should be interpreted as hypothesis-generating rather than as validated therapeutic protocols. Conclusions: Mechanism-based sequential field therapy may represent a rational strategy to optimize long-term control of actinic keratosis and field cancerization. Prospective comparative studies are needed to define optimal sequences, treatment intervals, patient selection criteria, and clinically meaningful endpoints, including sustained field clearance, recurrence reduction, tolerability, adherence, and prevention of progression to invasive cutaneous squamous cell carcinoma. Full article

Alzheimer’s disease (AD) and metabolic syndrome often occur together, sharing characteristics such as insulin resistance, dyslipidemia, and chronic inflammation. Metabolic dysfunction frequently precedes cognitive decline, indicating that early intervention might alter the disease’s progression. We investigated whether the GLP-1 receptor agonist semaglutide (SMGL) influences metabolic impairment and AD pathology in an AD mouse model. Male and female 5xFAD and wild-type (WT) mice on regular (RD) or high-fat diets (HFD) were administered SMGL for 13 weeks. SMGL-treated groups exhibited significant, context-dependent effects. In metabolically challenged 5xFAD HFD mice, treatment led to reduced body weight, improved glucose tolerance, normalized cholesterol levels, and a restored balance of adiponectin and leptin. These improvements were associated with reduced Aβ40 and Aβ42 levels, restored GLP-1 receptor expression, increased synaptophysin and βIII-tubulin levels, and enhanced spatial memory. SMGL also decreased Iba1 and CD68 immunoreactivity in the hippocampus and cortex, reduced macrophage infiltration, and lowered CD36 expression in visceral adipose tissue (VAT), indicating coordinated anti-inflammatory effects. WT RD mice showed minimal metabolic responses and a modest decline in Y-maze performance, suggesting that excessive GLP-1 receptor activation may disrupt neuronal homeostasis when metabolic status is normal. SMGL acts as a context-specific metabolic and neuroprotective agent, offering the greatest benefits under conditions of metabolic dysfunction. These findings in a preclinical model suggest that targeting early metabolic disturbances provides a testable hypothesis for attenuating AD-related neurodegeneration, though further translational studies are required. Full article

Melanoma is a highly aggressive and invasive form of skin cancer that arises from the uncontrolled growth of melanocytes. It is characterized by early spread through the lymphatic system and metastasis. The success of metastasis is linked to the ability of melanoma and other cancer cells to resist anoikis, a type of cell death that occurs when cells lose their adhesion to the extracellular matrix. Redox signaling plays an essential role in anoikis resistance. The balance between intracellular levels of nitric oxide (NO) and the reactive oxygen species (ROS) O₂⁻ and H₂O₂ stimulate signaling pathways related to proliferation and survival or cell death. A375 and SK-MEL-28 human melanomas cell lines, representing primary melanoma and lymph node metastatic melanoma cells, respectively, under suspension and adherent culture conditions were used to investigate the redox regulation of anoikis resistance. Both cell lines express the three isoforms of nitric oxide synthases (NOS) and NADPH oxidase 4 (NOX4) as endogenous sources of NO and ROS, respectively. When A375 cells in suspension were treated with the pan-NOS inhibitor L-NAME, their viability decreased. The treatment resulted in a decrease in FAK phosphorylation at Tyr397 and in ERK 1/2 phosphorylation. The expression of FAK, ERK 1/2, β-actin, and α-tubulin were significantly reduced. Treatment with L-NAME led to an increase in the expression of the metalloprotease MMP-9. SK-MEL-28 cells in suspension and treated with the NOX4 inhibitor, GKT36901, exhibited reduced viability. This was accompanied by the inhibition of FAK phosphorylation at Tyr397, ERK 1/2 phosphorylation, and a reduction in the expression of FAK, ERK 1/2, β-actin, and α-tubulin, with a slight elevation in the expression of MMP-9. Migration and invasion were strongly inhibited in A375 cells upon treatment with L-NAME, while treatment with GKT36901 had a marginal effect on the migration and invasion capacities of SK-MEL-28 cells. In summary, melanoma cells employ nitrosative and oxidative stress to shield themselves from anoikis. Nitric oxide was essential for melanoma cells at the primary site for resisting anoikis, while H₂O₂ contributed to anoikis resistance in metastatic melanoma cells. Full article