Cytoplasmic Processes Research Articles

Lysine succinylome analysis of MRSA reveals critical roles in energy metabolism and virulence.

MRSA's resistance poses a global health challenge. This study investigates lysine succinylation in MRSA using proteomics and bioinformatics approaches to uncover metabolic and virulence mechanisms, with the goal of identifying novel therapeutic targets. Mass spectrometry and bioinformatics analyses mapped the MRSA succinylome, identifying 8 048 succinylation sites on 1 210 proteins. These analyses included Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and protein-protein interaction (PPI) network construction (e.g. using the STRING database), providing a comprehensive functional and interactive landscape of succinylated proteins. The succinylated proteins were predominantly involved in cytoplasmic metabolic processes, with enrichment in glycolysis/gluconeogenesis and the tricarboxylic acid (TCA) cycle. Both of these pathways are critical for MRSA's energy production, growth, and virulence, supplying the necessary metabolic intermediates and energy to support bacterial survival and pathogenicity. Motif analysis revealed 13 conserved motifs, while PPI analysis highlighted FnbA as a central virulence factor. Succinylation significantly influences MRSA's metabolism and virulence, potentially impacting biofilm by modifying key proteins such as FnbA, bifunctional autolysin, and LuxS. These findings provide new avenues for developing antibiofilm strategies and therapeutic interventions against MRSA.

Roles of ROCK/Myosin Pathway in Macrothrombocytopenia in Bernard-Soulier Syndrome.

Megakaryocytes (MK) from Bernard-Soulier syndrome (BSS) induced pluripotent stem cells (iPSCs) yielded reduced numbers but increased sizes of platelets. The molecular mechanisms remain unclear. This study aims to determine roles of signaling molecules involved in this process. Wild-type (WT) iPSCs and iPSCs from BSS patients with GP1BA (BSS-A) or GP1BB (BSS-B) mutations were differentiated into MKs and platelets with or without myosin II inhibitor (blebbistatin), ROCK inhibitor (Y27632), and procaspase-3 activator (PAC-1). Proplatelet and platelet numbers and sizes were characterized. The iPSC lines containing tubulin-green fluorescent protein (GFP) reporters were constructed to observe proplatelet formation under time-lapse microscopy. BSS-derived MKs (BSS-MKs) yielded fewer but larger platelets compared with the WT. In the presence of blebbistatin, ROCK inhibitor, or PAC-1, WT, BSS-A, and BSS-B MKs could generate more platelets with decreased sizes, but PAC-1 caused CD42 loss on WT platelets. The proportions of proplatelet formation from MKs carrying tubulin-GFP were not different between WT and BSS-MKs, as well as among inhibitors. Notably, initially thick cytoplasmic processes were transformed into thin branching proplatelets over the observation time. The proplatelet shafts of BSS-MK became thinner in the presence of blebbistatin or ROCK inhibitor, but not of PAC-1, which displayed uneven F-actin distribution. Inhibition of the ROCK/myosin pathway, downstream of GpIb, could restore normal morphology of proplatelets in BSS-MKs. Procaspase-3 activation could increase platelet yields, but with abnormal proplatelet and platelet structures. Our model can be used for therapeutic drug screening and a disease model for platelet production in the future.

Unveiling the Impact of Allethrin-Related Mosquito Coil Exposure on Testicular Histology: Investigating the Protective Role of Vitamin C and withdrawal dynamics

Introduction: Allethrin is a common pyrethroid, one of the major component of mosquito coils that is noxious. The aim of the current study is to see the protective effect of Vitamin C on an induced testicular damage by Allethrin as well as comparing it to withdrawal prognosis. Material and method: The Wistar rats comprised of following groups: Group 1-control group , Groups II, III, and IV- exposure groups. Each group consisted of 12 rats. These were subjected to mosquito coil fumes continuously overnight for eight hours every day for a duration of twelve weeks. To demonstrate the effects of withdrawal, Wistar rats from group III were kept in an environment free from additional exposure for eight weeks after the 12-week exposure period. In addition, Group IV received Vitamin C. Result: Group II exhibited significant alterations in the testicular architecture, including conspicuous shrinkage of seminiferous tubules, an increase in intertubular space, thickening and disruption of the basement membrane, decreased thickness of the germinal epithelium, sloughing of germinal cells into the lumen, reduced numbers and size of spermatogenic cells, retracted cytoplasmic processes of Sertoli cells, interstitial edema, lipid vacuolation, and deformation of Leydig cells. Withdrawal in group III showed some histopathological improvements, while group IV, treated with Vitamin C, demonstrated even more remarkable enhancements. Conclusion: Exposure of Wistar Albino rats to mosquito coils containing allethrin led to notable histopathological changes. However, these adverse effects can be ameliorated by incorporating daily antioxidant intake, such as Vitamin C supplementation. KEY WORDS: Mosquito Coil, Allethrin, Testicular, Seminiferous Tubules, Vitamin C, Antioxidant.

Microarray analysis of microRNA profiles for assessing the therapeutic effects of sodium thiosulfate on end-stage renal disease combined with coronary artery calcification.

Coronary artery calcification (CAC) is a common complication in patients with end-stage renal disease (ESRD), which causes of increased cardiovascular mortality in maintenance hemodialysis patients. This study examined how sodium thiosulfate (STS) treatment affects the microRNA (miRNA) expression profiles of ESRD patients combined with CAC. A total of 18 patients with ESRD complicated with CAC were assigned to a control group that received conservative treatment or a test group that received STS treatment. The 2 groups were then sub-divided into a CGBT group (control group before treatment), TGBT group (test group before treatment), CGAT group (control group after treatment), and TGAT group (test group after treatment). Samples of peripheral venous blood were collected for analysis of biochemical indexes (hs-CRP, ALB, CHO, TG, Ca, P, BUN, Cr, bALP, iPTH, and FGF23) and used to screen for differentially expressed miRNAs that were displayed by hierarchical clustering and in a volcano plot. The functional roles of miRNA target genes were analyzed by Gene Ontology and Kyoto Encycolopedia of Genes and Genomes pathway analyses. Several miRNAs in serum samples were identified using quantitative real time PCR. STS treatment did not significantly change the biochemical indexes. A microarray analysis identified 67 miRNAs that were differentially expressed in the TGAT group vs. the TGBT group, and 28 -miRNAs that were differentially expressed in the CGAT group vs. the CGBT group. The miRNA target genes were associated with signal transduction, transcriptional regulation, cytoplasm and protein binding processes, the MAPK signaling pathway, PI3K-Akt signaling pathway, and various pathways in cancer. Validation experiments confirmed the suppressive effect of STS treatment on miR-337-5p/miR-409-5p expression and the promotive effect of STS on miR-376a-3p expression. MiR-337-5p/miR-409-5p/miR-376a-3p might be key regulators involved with the therapeutic effects of STS treatment in ESRD patients associated with arterial calcification.

The efficacy of plasma exosomal miRNAs as predictive biomarkers for PD-1 blockade plus chemotherapy in gastric cancer.

The response of gastric cancer (GC) patients to first-line programmed cell death 1 (PD-1) blockade and S-1 plus oxaliplatin (SOX) chemotherapy varies considerably, and the underlying mechanisms driving this variability remain elusive. Exosomal microRNAs (miRNAs or miRs) have emerged as potential biomarkers for efficacy prediction due to their roles in GC biology and stable expression in serum. In this study, we aimed to identify biomarkers to predict patients' response to anti-PD-1 therapy and further elucidate the potential mechanisms by which these exosomal miRNAs modulate the immune response in GC. Serum exosomes were extracted from 11 GC patients (five in the primary cohort and six in the validation cohort) treated with SOX and camrelizumab (a PD-1 inhibitor). High-throughput sequencing was performed to identify miRNA expression profiles, after which hierarchical clustering and a differential expression analysis were conducted. Functional enrichment analyses of the target genes for the significantly upregulated miRNAs were performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The validation of the candidate miRNAs was carried out by quantitative polymerase chain reaction (qPCR) in an independent cohort. MiRNA sequencing identified 3,083 miRNAs, of which 74 (42 upregulated and 32 downregulated) were differentially expressed between the responders and non-responders. The GO and KEGG pathway analyses of the top 20 upregulated miRNAs indicated that the target genes were significantly involved in transcription regulation, cytoplasmic processes, and protein binding, and that key pathways included the PI3K-AKT, MAPK, RAP1, and RAS signaling pathways. Consistent with the sequencing findings, the qPCR validation results showed significant differences in the expression levels of miRNA451a and miRNA142-5p between the responders and non-responders. This study identified specific plasma exosomal miRNAs in GC patients that differ between responders and non-responders to PD-1 monoclonal antibody therapy combined with chemotherapy. These miRNAs could serve as predictive biomarkers, paving the way for precision medicine and personalized therapy in the treatment of GC.

Regenerative endodontic therapy in immature teeth using photobiomodulation and photodynamic therapy; a histomorphological study in canine model

BackgroundRegenerative endodontic therapy (RET) is still coming up short to demonstrate histological evidence for true regeneration with clinically feasible protocol of cell homing in single visit approach.AimThe aim of the present study is to evaluate the regenerative potential of photobiomodulation (PBM) on RET in immature roots when photodynamic therapy (PDT) protocol is implemented for root canal disinfection in canine model.Materials and methodsSeventy-two root canals were recruited, with sixty assigned to experimental groups and twelve to positive and negative controls. Following the induction of pulp necrosis and apical periodontitis, the roots were divided into two experimental groups: Group I received RET followed by PBM (seven sessions with an 808 nm diode laser at 300 mW for 90 s), and Group II received RET without PBM. Follow-ups were conducted at 1, 2, and 3 months (subgroups A, B, and C respectively). Qualitative and quantitative assessment was carried out histologically. All data were statistically analyzed with the Mann-Whitney U test and Bonferroni’s adjustment, as well as Chi square test.ResultsThe newly formed hard tissue highly resembled true dentine where the dentinal tubules looked well organized lined by poly layers palisading pattern of rounded odontoblast-like cells with cytoplasmic processes extending through the predentine layer. GI exhibited statistically significantly higher scores of vital tissue infiltration and hard tissue deposition in subgroups A and B (P ≤ 0.05). The inflammatory cells scores were significantly lower in GI than in GII at all time intervals. However, no significance could be detected regarding apical closure.ConclusionThe disinfection protocol of PDT and subsequent irradiation with low power laser in PBM protocol pose a promising potential for regenerative endodontics in immature teeth.

The study of Alzheimer's disease risk diagnosis based on natural killer cell marker genes in the multi-omics data.

Alzheimer's disease (AD) is a common neurodegenerative disorder, currently lacking effective early diagnostic methods. However, natural killer (NK) cells may play a potential role in AD pathogenesis. This study aims to identify AD-related feature genes from NK cell markers to construct a diagnostic model and explore their potential biological mechanisms in AD. Single-cell RNA sequencing data was used to identify NK cell markers. A novel feature selection algorithm, adaptive dynamic graph convolutional network (ADGCN), was proposed to extract AD-related feature genes and construct a diagnostic model. Differential, correlation and enrichment analyses were performed to understand the biological mechanisms of these genes. Immune infiltration analysis compared the immune microenvironment between AD and controls. Two regulatory networks explored interactions between feature genes, transcription factors and microRNAs. The association between SNPs and feature genes' expression was examined through expression quantitative trait loci analysis. Differential CpG sites were identified to analyze their association with the NK cell markers' expression. We developed an optimal diagnostic model (ADGCN-XGBoost) with 17 feature genes, demonstrating high diagnostic effectiveness across datasets. These genes were primarily related to macromolecule biosynthesis, cytoplasmic translation biological processes and ribosome pathway, and potentially modulated immune infiltration of AD patients. We predicted 27 target miRNAs and 21 transcription factors influencing these genes. Multimodal analysis identified 57 significant SNP-gene associations and seven CpG-gene pairs. This study proposed a novel feature selection algorithm and developed a diagnostic model based on 17 feature genes, providing new potential biomarkers for AD diagnosis.

Immunohistochemical and ultrastructural identification of telocytes in the infantile hemangioma

ABSTRACT Telocytes (TCs) are a distinctive cell entity of the stromal microenvironment of multiple tumors; to date, their existence in infantile hemangioma (IH) remains almost unexplored. This study was therefore undertaken to characterize the immunophenotype, location, morphology, and ultrastructure of telocytes in the IH by means of immunohistochemistry, immunofluorescence confocal microscopy, and transmission electron microscopy. Telocytes were initially identified by CD34, PDGFR-α, Vimentin, and AQP-1 immunostaining. Analyzing the spatial relationship among telocytes, stem cells, endothelial cells, pericytes in the IH with AQP-1/CD31, AQP-1/Glut-1, AQP-1/α-SMA, AQP-1/CD146 and AQP-1/CD133 double immunofluorescence. TCs were immunonegative for CD31, Glut-1, CD146, α-SMA, CD133, and C-kit in the IH. The ultrastructural examination confirmed the presence of TCs, namely stromal cells with characteristic cytoplasmic processes (i.e. telopodes) forming labyrinthine networks around microvessels and releasing extracellular vesicles. Our study provides evidence that telocytes are present and PDGFR-α and AQP-1 are specific antigenic markers in the IH.

Immunohistochemical analysis and distribution of epithelial mast cells in the rat larynx and trachea.

Mast cells (MCs) in rat airways have been classified into two subtypes: epithelial MCs and connective tissue MCs (CTMCs). However, the immunohistochemical characteristics, cellular morphology, and distribution of epithelial MCs in the upper airways remain unclear. The present study investigated the morphological characteristics and distribution of epithelial MCs using 5-hydroxytryptamine (5-HT) and other immunohistochemical markers in sectioned or whole-mount preparations of the rat larynx and trachea. A double immunofluorescence analysis revealed the colocalization of 5-HT immunoreactivity with c-kit, a stem cell factor receptor commonly used as a MC marker, in both epithelial MCs and CTMCs. Dopa decarboxylase, an enzyme involved in 5-HT synthesis, was detected in both subtypes, suggesting their ability to synthesize and release 5-HT. Tryptase and histidine decarboxylase (a biosynthetic enzyme of histamine), which are well-known mediators of MCs, were exclusive to CTMCs. Epithelial MCs were pleomorphic with long cytoplasmic processes, whereas CTMCs were round and lacked cytoplasmic processes. The density of epithelial MCs was significantly higher in the glottis and cranial part of the trachea than in the epiglottis and other parts of the trachea. The present results showed that the morphology and immunohistochemical characteristics of epithelial MCs were different from those of CTMCs in the rat larynx and trachea, and variform epithelial MCs were predominantly located at the entrance of the upper airways. Epithelial MCs may release 5-HT to regulate innate immune responses by modulating epithelial cell functions at the entrance gate of the upper airways.

Nucleo-cytoplasmic distribution of SAP18 reveals its dual function in splicing regulation and heat-stress response in Arabidopsis

Dynamic shuttling of proteins between the nucleus and cytoplasm orchestrates vital functions in eukaryotes. Here, we reveal the multifaceted functions of Arabidopsis Sin3-associated protein 18 kDa (SAP18) in the regulation of development and heat-stress tolerance. Proteomic analysis demonstrated that SAP18 is a core component of the nuclear apoptosis- and splicing-associated protein (ASAP) complex in Arabidopsis, contributing to the precise splicing of genes associated with leaf development. Genetic analysis further confirmed the critical role of SAP18 in different developmental processes as part of the ASAP complex, including leaf morphogenesis and flowering time. Interestingly, upon heat shock, SAP18 translocates from the nucleus to cytoplasmic stress granules and processing bodies. The heat-sensitive phenotype of a SAP18 loss-of-function mutant revealed a novel role for SAP18 in plant thermoprotection. These findings significantly expand our understanding of the relevance of SAP18 for plant growth, linking nuclear splicing with cytoplasmic stress responses and providing new perspectives for future exploration of plant thermotolerance mechanisms.

Nuclear Type I Myosins are Essential for Life and Genome Organization.

The active transport of large biomolecules within a cell is critical for homeostasis. While the cytoplasmic process is well-studied, how the spacing of nucleoplasmic cargo is coordinated is poorly understood. We investigated the impact of myosin motors in the nucleus of budding yeast. We found that life requires a nuclear type I myosin whereas the essential type II or V myosins were not requisite in the nucleus. Nuclear depletion of type I myosins triggered 3D genome disorganization, nucleolar disruption, broad gene expression changes, and nuclear membrane morphology collapse. Genome disorganization occurred first supporting a model where type I myosins actively maintain genome architecture that scaffolds nuclear membrane and nucleolar morphologies. Overall, nuclear myosin is critical for the form and function of the nucleus.

Distribution and morphology of serotonin transporter-immunoreactive type I cells in the rat carotid body.

The present study reexamined the immunolocalization of membranous serotonin transporter (SERT) in the rat carotid body, and demonstrated SERT-immunoreactive cells of unreported morphology. SERT was immunohistochemically localized in a very small population of cell clusters or single type I cells (2.8%) immunoreactive for synaptophysin, the marker of these cells. Intense SERT immunoreactivity outlined the perinuclear cytoplasm and multiple cytoplasmic processes of type I cells. Of SERT-immunoreactive type I cells, 14.6% and 32.6% were immunoreactive for tyrosine hydroxylase (TH) and dopamine beta-hydroxylase, respectively, while 75.9% were immunoreactive for serotonin (5-HT). 5-HT-immunoreactive products were localized in cell bodies rather than cytoplasmic processes. SERT-immunoreactive type I cells were composed of an oval cell body with multiple threads and spherical or elongated cytoplasmic processes. Clusters or single SERT-immunoreactive type I cells were localized between or attached to other TH-immunoreactive type I cells by cell bodies or variform cytoplasmic processes. SERT-immunoreactive type I cells mainly contained bassoon-immunoreactive products in their cell bodies rather than their variform cytoplasmic processes. These results demonstrated the characteristic morphology of SERT-immunoreactive type I cells, which extend multiple cytoplasmic processes with variform terminal parts. Their morphology might be suitable for uptake of 5-HT to control the serotonergic modulation in the carotid body.

Protein-Sequence-Based Search of Nonreceptor ITAM-Like Regions to Identify Cytosolic Syk-Recruiting Proteins.

The recruitment of the protein spleen tyrosine kinase (Syk) to membrane-bound immune receptors is an essential step in initiating an immune response mediated through the activated receptors. Syk recognizes intracellular phosphorylated regions of membrane receptors known as immunoreceptor tyrosine-based activation motifs (ITAMs) defined by a sequence with two tyrosine (Y) amino acids separated by a certain spacing of six to eight residues: YXX(I/L)X6-8YXX(I/L). Syk with doubly phosphorylated ITAM is high-affinity and negatively regulated when Syk itself becomes phosphorylated. While the role of Syk in immune signaling is well characterized, recent information affords new functionality to Syk related to cytoplasmic processes, including the clearance of stress granules and P-bodies, both formed by liquid-liquid phase separation. Little to nothing is known about the molecular interactions involving Syk in these cytoplasmic processes. Given the essential role of receptor ITAMs in recruiting and localizing Syk for immune signaling, we explore here the possibility of a similar localization mechanism occurring for cytoplasmic processes by searching sequences of proteins related to Syk cytoplasmic function for regions that resemble receptor ITAMs. Protein sequence databases were generated from a Syk-dependent phosphoproteome and from genes related to P-bodies. A search of these databases for ITAM-like sequences yielded 102 unique hits, and 33 of these were synthesized and tested experimentally for binding to Syk tandem SH2 domains. The equilibrium dissociation constants were 0.1-50 μM for 28 peptides, and binding was negatively regulated by phosphorylation for many peptides. These results identify cytoplasmic proteins with potential for regulating the localization of Syk in a phosphorylation-dependent manner to nonmembrane cellular regions.

Murine glial protrusion transcripts predict localized Drosophila glial mRNAs involved in plasticity.

The polarization of cells often involves the transport of specific mRNAs and their localized translation in distal projections. Neurons and glia are both known to contain long cytoplasmic processes, while localized transcripts have only been studied extensively in neurons, not glia, especially in intact nervous systems. Here, we predict 1,740 localized Drosophila glial transcripts by extrapolating from our meta-analysis of seven existing studies characterizing the localized transcriptomes and translatomes of synaptically associated mammalian glia. We demonstrate that the localization of mRNAs in mammalian glial projections strongly predicts the localization of their high-confidence Drosophila homologs in larval motor neuron-associated glial projections and are highly statistically enriched for genes associated with neurological diseases. We further show that some of these localized glial transcripts are specifically required in glia for structural plasticity at the nearby neuromuscular junction synapses. We conclude that peripheral glial mRNA localization is a common and conserved phenomenon and propose that it is likely to be functionally important in disease.

The Biological Effect of Platelet-Rich Plasma on Rotator Cuff Tears: A Prospective Randomized In Vivo Study.

The positive effect of platelet-rich plasma (PRP) on tendon metabolism has been extensively investigated and proven in vitro. Additionally, in vivo animal studies have correlated the application of PRP with the enhancement of tenocyte anabolic activity in the setting of tendon degeneration. However, less is known about its in vivo effect on human tendon biology. The purpose of the current prospective randomized comparative study was to evaluate the effect of PRP on torn human supraspinatus tendon. Twenty consecutive eligible patients with painful and magnetic resonance imaging (MRI)-confirmed degenerative supraspinatus tendon tears were randomized in a one-to-one ratio into two groups. The patients in the experimental group (n = 10) underwent an ultrasound-guided autologous PRP injection in the subacromial space 6 weeks before the scheduled operation. In the control group (n = 10), no injection was made prior to surgery. Supraspinatus tendon specimens were harvested from the lateral end of the torn tendon during shoulder arthroscopy and were evaluated under optical and electron microscopy. In the control group, a mixed cell population of oval and rounded tenocytes within disorganized collagen and sites of accumulated inflammatory cells was detected. In contrast, the experimental group yielded abundant oval-shaped cells with multiple cytoplasmic processes within mainly parallel collagen fibers and less marked inflammation, simulating the intact tendon structure. These findings indicate that PRP can induce microscopic changes in the ruptured tendon by stimulating the healing process and can facilitate a more effective recovery.

Three-Dimensional Ultrastructure of Flower-Spray Nerve Endings in the Rat Carotid Sinus.

The flower-spray nerve endings are afferent nerve terminals in the carotid sinus that arise from carotid sinus nerve of glossopharyngeal nerve. However, the three-dimensional ultrastructural characteristics of flower-spray nerve endings and spatial relationships between the terminal parts and other cellular elements have not been fully understood. To elucidate their detailed relationship, backscattered electron imaging of serial sections was performed with a scanning electron microscope to produce a three-dimensional reconstruction of the flower-spray endings. The terminal parts of flower-spray endings were distributed horizontally approximately 5µm outside the external elastic membrane in the tunica adventitia of the internal carotid artery. The three-dimensional reconstruction showed that the terminal parts of flower-spray endings were flat with irregular contours and were partially covered by the thin cytoplasmic processes of Schwann cells. The complex consisting of the nerve terminals and associated Schwann cells was surrounded by a multilayered basement membrane. The terminal parts of the endings were also surrounded by fibroblasts with elastic fibers and collagen fibrils. Secretory vesicles without an electron-dense core were observed in the terminal parts of the endings. The accumulation of vesicles just below the axonal membrane was observed in terminal parts not covered by Schwann cell cytoplasmic processes on both the luminal and basal sides. Swollen mitochondria, concentric membranous structures, and glycogen granule-like electron-dense materials were often noted in some of the terminal parts of the endings and the parent axon. Collectively, the present results suggest that flower-spray endings are baroreceptors because their morphology was similar to other mechanoreceptors. Furthermore, flower-spray endings may be affected by glutamate secreted in an autocrine manner.

Dentin Collagen versus Er:YAG Laser as Surface Biomodifiers for Intact Root Slices Simulating Delayed Replanted Roots.

Objective: To evaluate effects of dentin collagen versus Er:YAG laser application through enhancing human periodontal ligament fibroblast (PDLF) cells to attach to intact root surfaces imitating delayed replanted roots. Background Data: Accidental traumatic injuries with teeth avulsion are managed by replantation. Root resorption, poor conditioning, and non-viable fibroblasts are factors responsible for failure. Methods: Thirty six human healthy single-rooted premolars were collected. Six teeth were used for PDLF, six teeth used for dentin collagen, whereas the remaining 24 teeth (48 root slices) were used for PDLF cell density and morphology. Each root was soaked in 5.25% NaOCl. Three groups (n = 16 slices/each) were planned as follows: I: Control (untreated); II: dentin collagen application; III: Er:YAG laser irradiation (4 mm distance, 40 mJ/pulse, under coolant). Following incubation, cell density and morphology of PDLF were investigated under SEM. Statistical analysis was performed using analysis of variance with Scheffé's test, and p < 0.05 was considered significant. Results: All groups showed increased cultured PDLF following incubation. Regarding cell density, attached PDLFs were significantly lower in untreated controls (36.5 ± 6.36) (p < 0.00001 i.e., <0.05) in negative empty and/or light cellular areas, compared with dentin collagen (65 ± 6) and laser-irradiated (66.75 ± 5.77) groups that did not show significant differences (p = 0.940 i.e., >0.05) and showed intermediate and/or heavy cellular areas. Regarding cell morphology, controls showed round and/or oval appearance with less lamellipodia, whereas dentin collagen and laser groups showed flat morphology with cytoplasmic processes. Conclusions: Both dentin collagen and Er:YAG laser showed comparable effectiveness as biomodification tools with good biocompatibility for human PDLF cell attachment on intact root slices imitating delayed replantation. Dentin collagen as a natural bioactive material is considered an alternative to Er:YAG laser to enhance the regenerative effects.

Cellular Distribution and Ultrastructural Changes in HaCaT Cells, Induced by Podophyllotoxin and Its Novel Fluorescent Derivative, Supported by the Molecular Docking Studies.

Podophyllotoxin (PPT) is an active pharmaceutical ingredient (API) with established antitumor potential. However, due to its systemic toxicity, its use is restricted to topical treatment of anogenital warts. Less toxic PPT derivatives (e.g., etoposide and teniposide) are used intravenously as anticancer agents. PPT has been exploited as a scaffold of new potential therapeutic agents; however, fewer studies have been conducted on the parent molecule than on its derivatives. We have undertaken a study of ultrastructural changes induced by PPT on HaCaT keratinocytes. We have also tracked the intracellular localization of PPT using its fluorescent derivative (PPT-FL). Moreover, we performed molecular docking of both PPT and PPT-FL to compare their affinity to various binding sites of tubulin. Using the Presto blue viability assay, we established working concentrations of PPT in HaCaT cells. Subsequently, we have used selected concentrations to determine PPT effects at the ultrastructural level. Dynamics of PPT distribution by confocal microscopy was performed using PPT-FL. Molecular docking calculations were conducted using Glide. PPT induces a time-dependent cytotoxic effect on HaCaT cells. Within 24 h, we observed the elongation of cytoplasmic processes, formation of cytoplasmic vacuoles, progressive ER stress, and shortening of the mitochondrial long axis. After 48 h, we noticed disintegration of the cell membrane, progressive vacuolization, apoptotic/necrotic vesicles, and a change in the cell nucleus's appearance. PPT-FL was detected within HaCaT cells after ~10 min of incubation and remained within cells in the following measurements. Molecular docking confirmed the formation of a stable complex between tubulin and both PPT and PPT-FL. However, it was formed at different binding sites. PPT is highly toxic to normal human keratinocytes, even at low concentrations. It promptly enters the cells, probably via endocytosis. At lower concentrations, PPT causes disruptions in both ER and mitochondria, while at higher concentrations, it leads to massive vacuolization with subsequent cell death. The novel derivative of PPT, PPT-FL, forms a stable complex with tubulin, and therefore, it is a useful tracker of intracellular PPT binding and trafficking.

Differentiation of the structure of dentinal tubules and dentinal canaliculi in human teeth of different ages

The dentinal tubules are designed to protect the odontoblast processes, which leave behind a cytoplasmic process during tooth development. Around the cytoplasmic process, a dentin matrix is deposited, which eventually mineralizes. However, the question of the role and structure of the cytoplasmic process of the odontoblast in each dentinal tubule after dentin has completely finished the formation process remains an unresolved issue. We investigated the dentinal tubules of 20 permanent teeth (premolars and molars) of people of different ages using a scanning electron microscope. The occlusal surfaces and longitudinal fracture planes of both decalcified and non-decalcified native tooth preparations were examined. In longitudinally split teeth at the periphery of the pulp chamber of a young human premolar, odontoblasts can be seen forming a continuous layer adjacent to the parapulpal dentin. Each of the odontoblasts has a separate process that penetrates into the dentinal tubule. More peripheral parts of the dentinal tubules were either empty or contained cylindrical structures that were better visualized after acid etching on longitudinally split samples. Etched split dentinal tubules in the outer dentin more often contained cylindroid tubular structures. In each individual dentinal tubule, the odontoblast processes are arranged in the form of thin-walled tubules, which, with the help of a supporting fibrillar framework, occupy a central position. On the occlusal surface of a mature human molar, the intertubular dentin has the appearance of a smooth-surfaced structure. Practically all dentinal tubules contain more or less preserved dentinal canaliculi, indicating their fairly pronounced resistance to adverse factors. Inside the lumen of the dentinal tubules, three different types of structures are observed: odontoblast processes, cylindrical structures, and collagen fibers. Odontoblast processes are visualized both along the entire length of the dentinal tubules and only in the parapulpal parts of the dentinal tubules. Their peripheral parts were either empty or contained cylindrical structures that likely correspond to the laminae limitantes. Collagen fibers often form a fibrillar network that on one side intertwines into the dentinal canaliculus, and on the other side is connected to the walls of the dentinal tubules due to perpendicular microtubules for anchoring fibrils. Collagen fibers are most numerous in the parapulpal parts of the dentinal tubules. This study only partially explained certain aspects of the dentin microstructure, but further in-depth studies of dentin ultrastructure are necessary to more fully understand the pathology of hard tooth tissues in people of different ages and the possibilities for its treatment and prevention.

VCP regulates early tau seed amplification via specific cofactors.

Neurodegenerative tauopathies may progress based on seeding by pathological tau assemblies, whereby an aggregate is released from one cell, gains entry to an adjacent or connected cell, and serves as a specific template for its own replication in the cytoplasm. In vitro seeding reactions typically take days, yet seeding into the complex cytoplasmic milieu happens within hours, implicating a machinery with unknown players that controls this process in the acute phase. We used proximity labeling to identify factors that control seed amplification within 5h of seed exposure. We fused split-APEX2 to the C-terminus of tau repeat domain (RD) to reconstitute peroxidase activity 5h after seeded intracellular tau aggregation. Valosin containing protein (VCP/p97) was the top hit. VCP harbors dominant mutations that underlie two neurodegenerative diseases, multisystem proteinopathy and vacuolar tauopathy, but its mechanistic role is unclear. We used immortalized cells and human neurons to study the effects of VCP on tau seeding. We exposed cells to fibrils or brain homogenates in cell culture media and measured effects on uptake and induction of intracellular tau aggregation following various genetic and chemical manipulations of VCP. VCP knockdown reduced tau seeding. Chemical inhibitors had opposing effects on aggregation in HEK293T tau biosensor cells and human neurons alike: ML-240 increased seeding efficiency, whereas NMS-873 decreased it. The inhibitors were effective only when administered within 8h of seed exposure, indicating a role for VCP early in seed processing. We screened 30 VCP co-factors in HEK293T biosensor cells by genetic knockout or knockdown. Reduction of ATXN3, NSFL1C, UBE4B, NGLY1, and OTUB1 decreased tau seeding, as did NPLOC4, which also uniquely increased soluble tau levels. By contrast, reduction of FAF2 increased tau seeding. Divergent effects on tau seeding of chemical inhibitors and cofactor reduction indicate that VCP regulates this process. This is consistent with a dedicated cytoplasmic processing complex based on VCP that directs seeds acutely towards degradation vs. amplification.