Search Results (301)

Ultraviolet B radiation is a major cause of skin aging, cellular senescence, and inflammaging, mediated by the excessive production of reactive oxygen species (ROS) and induction of apoptosis. This study evaluated the photo-protective effects of astaxanthin, one of the strongest natural antioxidants, in UVB-treated keratinocytes. The antioxidant capacity of astaxanthin was evaluated using ABTS, DPPH, and NBT/riboflavin/SOD assays. HaCaT cells were exposed to 30 mJ/cm² of UVB radiation. Photoprotective effects and accumulated ROS were evaluated in UVB-irradiated HaCaT cells by MTT and DCFH-DA assays. Nitric oxide levels were quantified using the Griess reagent. Apoptosis was assessed by dual staining using acridine orange/ethidium bromide, lysosomal integrity by acridine orange uptake, and cell migration by scratch assay. Cell adhesion was assessed on ECM-coated Nunc plates. Finally, we formulated a 0.5% astaxanthin-enriched cream. Astaxanthin mitigated UVB-induced damage by reducing intracellular ROS levels by 3.7-fold, decreasing nitric oxide production to 29.8 ± 7.7% at the highest concentration, and maintaining lysosomal integrity. The carotenoid significantly enhanced cell viability, increasing it from 60.64 ± 8.3% in UV-treated cells to 102.1 ± 3.22% at 40 µM. Moreover, treated cells showed a significant reduction (p < 0.001) in the apoptotic rate (37.7 ± 3.1 vs. 87.7 ± 3.8 in UVB-irradiated cells, as evidenced by reduced chromatin condensation and nuclear fragmentation. Astaxanthin also enhanced tissue repair, as evidenced by increased cell migration and adhesion to several extracellular matrix (ECM) proteins (poly-L-lysine, laminin, fibrinogen, vitronectin and collagen I). In silico molecular docking predicted strong binding affinities between astaxanthin and key cellular targets, including JAK2 (−9.9 kcal/mol, highest affinity), STAT3, FAK, COX-2, NF-k-B, MMP2, and MMP9. The formulated cream demonstrated an in vitro SPF of 7.2 ± 2.5. Astaxanthin acts as a multifunctional photoprotective compound, providing a strong rationale for its incorporation into cosmetic and dermatological formulations, as further supported by the successful formulation and in vitro SPF estimation of an astaxanthin-enriched cream. Full article

The interplay between chromatin structure and phase-separating proteins is an emerging topic in cell biology with implications for understanding disease states. Here, we investigate the functional relationship between bromodomain protein 4 (BRD4) and chromatin architecture. By combining molecular dynamics simulations with live-cell imaging, we demonstrate that BRD4, when mutated at specific N-terminus sites, significantly impacts the organization and dynamics of chromatin nanodomains, known as nucleosome clutches. Our findings reveal that a constitutively phosphorylated mutant of BRD4 condenses nucleosome clutches, while treatment with (+)-JQ1 increases the diffusion dynamics of single nucleosomes and decondenses nucleosome clutches. Simultaneously, we demonstrate that BRD4 mutations can alter localization of BRD4 to chromatin as well as modify single nucleosome dynamics. These results suggest that both chromatin binding and phase separation of BRD4 could co-regulate the nanoscale chromatin architecture and the chromatin microenvironment. Our observations shed light on the nuanced regulation of chromatin structure by BRD4, offering insights into its role in maintaining the nuclear architecture and transcriptional activity. Full article

The buccal micronucleus cytome assay (BMCyt) is a validated, non-invasive biomonitoring method used to detect early genotoxic and cytotoxic changes linked to environmental and occupational exposures. Healthcare workers, especially nurses and dentists, are routinely exposed to genotoxic agents such as anesthetic gases, cytotoxic drugs, ionizing radiation, and heavy metals. This study compared seven cytological biomarkers in exfoliated buccal cells from female nurses, dentists, and teachers to assess multivariate cytogenetic differences and potential occupational influences. Samples were collected from 32 nurses, 41 dentists, and 47 teachers, and 3000 cells per participant were evaluated for micronuclei (MN) and six additional nuclear abnormalities. Group differences were examined using MANOVA and permutation MANOVA, followed by pairwise tests, and visualized with Principal Component Analysis (PCA). Significant multivariate differences were found between nurses and both dentists and teachers (p = 0.003), supported by permutation tests, while dentists and teachers did not differ. PCA explained 56% of the variance and showed apparent clustering of nurses. Chromatin condensation and MN were the main contributors to group separation. Nurses had significantly higher MN (p ≤ 0.001) and karyorrhexis (p ≤ 0.0004) than dentist and teachers. Overall, nurses showed a distinct cytogenetic profile consistent with greater genotoxic susceptibility. Full article

Many cellular processes, including gene expression regulation, DNA replication and repair, as well as proper condensation and segregation of chromosomes, require highly coordinated remodeling of chromatin. Cohesin and condensins, the structural maintenance of chromosomes (SMC) protein complexes that function as ATP-powered loop extrusion motors, are key determinants of chromatin structure. The genetic loss of their function is lethal, whereas inducible degradation approaches enable rapid, robust analysis of the depletion phenotype. In this review, we discuss new insights into chromatin folding through each cell cycle phase from the auxin-inducible degradation (AID) system. We review the mechanisms by which condensins and cohesins contribute to the helical organization of mitotic chromosomes and to the maintenance of chromosome territories in interphase. Additionally, we discuss studies examining the roles of TOP2A, KIF4A, and SRBD during mitosis using the AID system. We then outline emerging principles of the mitotic-to-interphase transition and how targeted degradation of chromatin proteins reshapes this process. Finally, we highlight and discuss new advances in understanding interphase chromatin organization revealed by AID-based studies. Full article

Cadmium (Cd) induces oxidative stress and disrupts nuclear organization and chromatin-associated metabolic processes in plant cells. Therefore, identifying natural, biodegradable, non-bioaccumulative compounds that enhance plant tolerance to heavy metals is crucial. We hypothesized that Cd exposure (175 µM CdCl₂, 24 h) activates mitogen-activated protein kinases (MAPKs), triggering defined epigenetic modifications that lead to transcriptional repression, and that thyme oil (TO; 0.03% (v/v), emulsified) mitigates these effects by stabilizing chromatin organization. We analyzed nuclear MAPK (p44/42) activation, global DNA methylation (5-methylcytosine; 5-mC), and selected histone modifications as key components of early stress signaling and epigenetic regulation. We found that Cd exposure doubled global 5-mC levels and caused pronounced alterations in histone marks, including decreases in H3K4Me2 (~34%), H3T45Ph (~48%), and H4K5Ac, accompanied by strong increases in H3K9Ac (~57%) and H3K56Ac (~148%). These changes were associated with chromatin condensation and reduced transcriptional activity. In contrast, co-treatment with TO maintained MAPK activity and epigenetic parameters close to control levels, preventing chromatin compaction and transcriptional repression. Together, these findings indicate that TO stabilizes the nuclear signaling–epigenetic interface under Cd stress and represents a promising bioprotective strategy. This work provides the first demonstration that TO modulates both MAPK activation and Cd-induced histone modifications in plants. Full article

Background: Male infertility is a common reproductive disorder, affecting about 7% of men in the general population. Despite its prevalence, the cause of infertility is often unknown. This case report presents the results of a comprehensive evaluation of a patient with severe oligoasthenoteratozoospermia and primary infertility. Methods: The patient underwent clinical, andrological, and genetic examinations, including semen analysis, transmission electron microscopy, cytogenetic examination, molecular analysis of the AZF locus and the CFTR gene, whole-exome sequencing, and Sanger sequencing. Results: Semen analysis revealed severe oligoasthenoteratozoospermia. Transmission electron microscopy showed acrosome detachment from the nucleus in 49% of the spermatozoa. A high percentage (54%) of spermatozoa with insufficiently condensed (“immature”) chromatin was also observed. No chromosomal abnormalities, Y chromosome microdeletions, or pathogenic CFTR gene variants were identified. Whole-exome sequencing revealed a novel c.821G>C variant (chrX:127185365G>C; NM_138289.4) in the ACTRT1 gene (Xq25). This variant was hemizygous in the patient and heterozygous in his mother, as determined by Sanger sequencing. According to the ACMG guidelines (PM2, PP3), this missense variant in the ACTRT1 gene was classified as a variant of uncertain clinical significance (VUS). Amino acid conservation and 3D protein modeling predict that the identified variant has a deleterious effect on the protein. Conclusions: This study suggests a potential link between a novel ACTRT1 variant and a specific teratozoospermia phenotype. Further functional studies are needed to confirm this association and determine the role of the gene in X-linked male infertility. Full article

The RCC1 gene is active in ensuring many cellular functions related to cell division in Drosophila melanogaster and Homo sapiens. A detailed comparison of the structure and functions of the RCC1 gene in Drosophila melanogaster and Homo sapiens was carried out using different analytical techniques (bioinformatics, immunofluorescence and confocal microscopy, FISH, and molecular genetic methods). The Drosophila RCC1 gene belongs to the family of housekeeping genes, since it resides in the interbands and gray bands of polytene chromosomes within aquamarine/lazurite chromatin in D. melanogaster. Furthermore, the databases demonstrate that RCC1 in D. melanogaster is expressed in all the tissues at all the developmental stages. According to The Human Protein Atlas, RCC1 in humans also exhibits low tissue specificity for 29 tissues. Immunostaining of polytene chromosomes with RCC1 antibodies revealed approximately 260 sites of RCC1 protein localization exclusively in black bands (sites of developmental genes) and in heterochromatin. The size of the coding gene portions is almost identical for D. melanogaster and H. sapiens, being ~2 kb. The group of Drosophila proteins related to condensed chromatin, RCC1 being a member of this group, has homologs forming similar interaction networks in humans. The conserved nature of the RCC1 gene has been confirmed by cell cycle studies in both species. It was found that expression of the RCC1 gene is upregulated in glioblastoma; the RCC1 protein predominantly resides on centrioles during metaphase. Full article

The RNAs present in spermatozoa play a crucial role in reproduction and embryonic development. They represent a promising diagnostic tool for assessing male infertility. However, their extraction is challenging due to their low concentration and highly condensed chromatin structure, as well as the presence of numerous cellular contaminants. These challenges vary across species and require the development of an optimized and reliable isolation method to obtain high-quality RNAs, which is essential for further molecular analyses regarding the roles played by these RNAs. This study evaluated two RNA extraction methods for spermatozoa in humans and other mammals (dogs, stallions, and bulls): a standard method using the NucleoSpin RNA^® II kit (Macherey-Nagel) and an optimized method that combined this kit with dithiothreitol and TRIzol™ pretreatment. In addition, the samples underwent pre-purification to eliminate somatic cells. The optimized method produced a significantly higher total RNA yield along with better purity, which was confirmed by the absence of the 18S and 28S ribosomal RNA peaks, indicating the absence of somatic cell contamination. Additionally, RT-PCR was performed to validate the presence of sperm-specific markers. The quality of the extracted RNAs was assessed by sequencing the mRNA encoding the human olfactory receptor OR1D2 and observing the resulting band on an agarose slab gel with a size corresponding to its entire open reading frame. By addressing long-standing challenges in sperm RNA isolation, our method provides an easy and standardized technique for research in reproductive biology and for advancing our understanding of paternal contributions to transgenerational inheritance. Full article

Infertility is a major health problem affecting about 15% of couples worldwide. Male etiology is found in almost one-third of cases. This study identified the nature of the relationship between sperm DNA fragmentation (SDF), sperm chromatin condensation (SCC) and sperm parameters. In this study, 80 samples were analyzed using two methods: the TUNEL technique to assess sperm DNA quality and aniline blue coloration to determine the level of chromatic condensation of spermatozoa. In addition, to specify the standard sperm parameters, the spermogram and the spermocytogram were analyzed. The main results revealed a significant difference between SDF and motility and, similarly, between SCC, motility, and teratozoospermia macrocephaly types (p < 0.0001, p < 0.0001, respectively), but no differences between SCC, SDF, and the other sperm parameters (p > 0.99). Full article

The DNA Damage Response (DDR) network is an essential machinery for maintaining genomic integrity, with DDR defects being implicated in cancer initiation, progression, and treatment resistance. Moreover, oxidative stress, an imbalance between reactive oxygen species production and antioxidant defense, can significantly impact cell viability, leading to cell death or survival. Herein, we tested the hypothesis that DDR-related signals and redox status measured in multiple myeloma (MM) cell lines correlate with the sensitivity to genotoxic insults. At baseline and following irradiation with Ultraviolet C (UVC; 50 J/m²) or treatment with melphalan (100 μg/mL for 5 min) DDR-related parameters, redox status expressed as GSH/GSSG ratio and apurinic/apyrimidinic sites were evaluated in a panel of eleven human MM cell lines and one healthy B lymphoblastoid cell line. We found that MM cell lines with increased apoptosis rates displayed significantly higher levels of endogenous/baseline DNA damage, reduced GSH/GSSG ratio, augmented apurinic/apyrimidinic lesions, decreased nucleotide excision repair and interstrand crosslinks repair capacities, and highly condensed chromatin structure. Taken together, these findings demonstrate that DDR-related parameters and redox status correlate with the sensitivity of MM cells to DNA-damaging agents, specifically melphalan, and, if further validated, may be exploited as novel sensitive/effective biomarkers. Full article

This study’s objective was to evaluate genotoxic effects on automotive paint workers who are exposed to a complex mixture of VOCs, heavy metals, and solvents. Biological samples, including blood, urine, and buccal epithelial cells, were collected from 80 exposed workers and 80 demographically matched control subjects. DNA damage was assessed using the alkaline COMET assay in lymphocytes and whole blood. The Buccal Micronucleus Cytome (BMCyt) assay was also employed to identify cytogenetic abnormalities. Additionally, trichloroacetic acid (TCA), hippuric acid (HA), phenol, and lead (Pb) levels were measured as biomarkers of exposure. A significant increase in DNA damage was observed in the lymphocytes and whole blood of exposed workers (p < 0.05) BMCyt analysis also revealed higher frequencies of micronuclei (MN), binucleated cells, condensed chromatin (CC), and karyorrhectic (KHC) and pyknotic cells (PYC) in buccal cells (p < 0.05). Elevated levels of urinary HA, phenol, TCA, and blood lead indicated systemic chemical exposure. DNA damage positively correlated with these biomarkers, supporting a strong link between chronic occupational exposure and genotoxicity. The findings from this study highlight the critical importance of implementing effective safety measures and consistent biomonitoring for paint workers to prevent adverse health effects. Full article

Essential oils are increasingly recognized as promising agents for sustainable weed control due to their selectivity and complex modes of action. This study evaluated the effects of Acorus calamus essential oil (SEO) on mitosis in two Fabaceae species (Vicia faba, Lupinus luteus) and two Brassicaceae species (Brassica napus, Arabidopsis thaliana) treated with species-specific IC₅₀ concentrations (0.03%, 0.025%, 0.01%, and 0.005%, respectively). Previous research showed that SEO induces oxidative stress and S-phase delay via genome instability. Here, SEO consistently disrupted mitosis across all species, reducing mitotic index by 50–60%, decreasing Cdc2 (CDKA homolog) levels, and causing chromosomal aberrations, including uneven chromatin condensation, sticky chromosomes, bridges, and micronuclei. Cells accumulated in metaphase and exhibited abnormal karyokinetic and cytokinetic spindles. Immunolabeling revealed thick, tightly packed microtubules and actin filaments, indicating excessive stabilization and impaired reorganization. Epigenetic regulation was also affected: H3T3 phosphorylation was abnormally strong, widely distributed, and persistent into anaphase/telophase, while H3S10Ph intensity was weakened. These results suggest that SEO targets multiple components of mitotic machinery and epigenetic control, regardless of species. The observed selectivity depends on dosage, not mechanism. This multi-targeted action may limit the development of plant resistance, supporting the potential of SEO as a bioherbicide in sustainable agriculture. Full article

Long noncoding RNAs (lncRNAs) have emerged as key regulators of gene expression during seed development and physiology. This review examines the diverse roles of lncRNAs in key stages of seed development, including embryogenesis, maturation, dormancy, germination, and aging. It integrates the current understanding of the biogenesis and classification of lncRNAs, emphasizing their functional mechanisms in seeds, particularly those acting in cis and trans. These mechanisms include the scaffolding of polycomb and SWI/SNF chromatin remodeling complexes, the guidance of RNA-directed DNA methylation, the ability to function as molecular decoys, and the modulation of small RNA pathways via competitive endogenous RNA activity. This review highlights the regulatory influence of lncRNAs on abscisic acid (ABA) and gibberellin (GA) signaling pathways, as well as light-responsive circuits that control dormancy and embryonic root formation. Endosperm imprinting processes that link parental origin to seed size and storage are also discussed. Emerging evidence for epitranscriptomic modifications, such as m6A methylation, and the formation of LncRNA–RNA-binding protein condensates that maintain resting states and coordinate reserve biosynthesis are also reviewed. Advances in methodologies, including single-cell and spatial transcriptomics, nascent transcription, direct RNA sequencing, and RNA–chromatin interaction mapping, are expanding the comprehensive lncRNA landscape during seed development and germination. These advances facilitate functional annotation. Finally, possible translational research applications are explored, with a focus on developing lncRNA-based biomarkers for seed vigor and longevity. Full article

Background/Objectives: Ferroptosis is a regulated form of cell death that occurs in the state of oxidative–antioxidative imbalance of an organism. The main components of ferroptosis are lipid peroxidation and iron accumulation. Cells experiencing ferroptosis show swelling, shrunken mitochondria with an abnormal structure, atrophic cristae, dense mitochondrial membranes, and ruptured outer membrane. Ferroptotic cells demonstrate a normal nucleus size without nuclear concentration, and neither condensation nor chromatin margination. Ferroptosis is regulated by multiple protein, genetic, and metabolic factors. The aim of this article is to present ferroptosis as a model of cell death occurring in various conditions and diseases. Methods: A literature search of PubMed, Web of Science was performed. Search terms included “ferroptosis”, “lipid peroxidation”, “iron”, and “cell death”. Results: Ferroptosis affects the onset, course, progression, and treatment of diseases, including neurodegenerative diseases, cancer diseases, autoimmune diseases, and hemorrhages. By using appropriate ferroptosis moderators, it is possible to influence the course of the disease in patients. Conclusions: By understanding the ferroptosis phenomenon well, it is possible to regulate its occurrence by considering the action of oxidative and antioxidant factors. A comprehensive understanding of ferroptosis and the factors regulating this process should be the goal in therapy for many diseases. Full article

Background: Often, neoadjuvant therapy, which relies on the induction of double-strand breaks (DSBs), is used prior to surgery to shrink tumors by inducing cancer cell apoptosis. However, recent studies have suggested that this treatment may also induce a fluctuating state between senescence and stemness in PA-1 embryonal carcinoma cells, potentially affecting therapeutic outcomes. Thus, the respective epigenetic pathways are up or downregulated over a time period of days. These fluctuations go hand in hand with changes in spatial DNA organization. Methods: By means of Single-Molecule Localization Microscopy in combination with mathematical evaluation tools for pointillist data sets, we investigated the organization of euchromatin and heterochromatin at the nanoscale on the third and fifth day after etoposide treatment. Results: Using fluorescently labeled antibodies against H3K9me3 (heterochromatin tri-methylation sites) and H3K4me3 (euchromatin tri-methylation sites), we found that the induction of DSBs led to the de-condensation of heterochromatin and compaction of euchromatin, with a peak effect on day 3 after the treatment. On day 3, we also observed the co-localization of euchromatin and heterochromatin, which have marks that usually occur in exclusive low-overlapping network-like compartments. The evaluation of the SMLM data using topological tools (persistent homology and persistent imaging) and principal component analysis, as well as the confocal microscopy analysis of H3K9me3- and H3K4me3-stained PA-1 cells, supported the findings that distinct shifts in euchromatin and heterochromatin organization took place in a subpopulation of these cells during the days after the treatment. Furthermore, by means of flow cytometry, it was shown that the rearrangements in chromatin organization coincided with the simultaneous upregulation of the stemness promotors OCT4A and SOX2 and senescence promotors p21Cip1 and p27. Conclusions: Our findings suggest potential applications to improve cancer therapy by inhibiting chromatin remodeling and preventing therapy-induced senescence. Full article