Search Results (287)

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

Background/Objectives: Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, remains a major neglected tropical disease, with over six million cases concentrated, primarily in Latin America. Despite decades of research, treatment continues to rely on two outdated drugs—benznidazole and nifurtimox—both of which exhibit limited efficacy and are associated with severe side effects. In this context, drug repurposing presents a promising strategy to accelerate the development of safer and more effective therapies. Nitroxoline, a hydroxyquinoline compound widely used in Europe to treat bacterial urinary tract infections, has recently garnered attention for its broad-spectrum antimicrobial and anticancer activities. This study evaluated the antitrypanosomal potential of nitroxoline against both epimastigote and intracellular amastigote forms of T. cruzi, demonstrating significantly greater efficacy than benznidazole. Methods: In addition to its antiparasitic activity, we investigated the mechanism of parasite death and found that nitroxoline induces hallmarks of programmed cell death, including chromatin condensation, mitochondrial membrane depolarization, ATP depletion, reactive oxygen species accumulation, and increased membrane permeability. These cellular events are critical for minimizing host tissue inflammation and suggest a safer therapeutic profile. Results: The nitroxoline was shown to induce greater activity than the reference treatment, benznidazole, in addition to triggering events related to apoptotic or silent cell death. Conclusions: Given its established clinical use and favorable safety data, nitroxoline emerges as a strong candidate for further investigation as a repurposed treatment for Chagas disease. Future work should focus on in vivo efficacy, pharmacokinetics, and drug delivery strategies to enhance systemic bioavailability. Full article

Advanced renal cell carcinoma (RCC) has a poor prognosis; this drives the exploration of alternative systemic therapies to identify more effective treatment options. Recent research has revealed that crebanine, an alkaloid derivative of the Stephania genus, induces apoptotic effects in various cancers; however, a thorough investigation of the role of crebanine in RCC has not been conducted thus far. For this study, we evaluated tumor cell viability, clonogenicity, cell-cycle distributions, morphological changes, and cell mortality with the aim of exploring the antitumor effects of crebanine in RCC. Furthermore, we compared gene and protein expressions using RNA sequencing analysis and Western blotting. The findings indicated that crebanine significantly inhibited RCC colonies and caused G1-phase cell-cycle arrest with sub-G1-phase accumulation, thus leading to suppressed cell proliferation and cell death. In addition, Hoechst 33342 staining was used to observe apoptotic cells, which revealed chromatin condensation and a reduction in the nuclear volume associated with apoptosis. Further, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that differentially expressed genes are involved in the initiation of DNA replication, centrosome duplication, chromosome congression, and mitotic processes in the cell cycle along with signaling pathways, such as I-kappaB kinase/NF-kappaB signaling, Hippo signaling, and intrinsic apoptotic pathways. Consistent with GO and KEGG analyses, increased levels of cleaved caspase-3, cleaved caspase-7, and cleaved PARP, and decreased levels of cIAP1, BCL2, survivin, and claspin were observed. Finally, the expressions of G1/S phase transition cyclin D1, cyclin E/CDK2, and cyclin A2/CDK2 complexes were downregulated. Overall, these findings supported the potential of crebanine as an adjuvant therapy in RCC. Full article

Alzheimer’s disease (AD), the most prevalent form of neurodegenerative dementia, is characterized by progressive cognitive decline and neuronal loss. Despite advances in pharmacological treatments, current therapies remain limited in efficacy and often induce adverse effects. Increasing evidence highlights oxidative stress, mitochondrial dysfunction, and disrupted neurotrophic signaling as key contributors to AD pathogenesis. Pulsed electromagnetic fields (PEMFs) are emerging as a non-invasive, multifactorial approach with promising biological effects. In this study, we investigated the neuroprotective potential of PEMFs in NGF-differentiated PC12 cells exposed to hydrogen peroxide (H₂O₂) or amyloid-β peptide (Aβ), both of which model pathological features of AD. PEMF treatment significantly counteracted H₂O₂- and Aβ-induced cytotoxicity by restoring cell viability, reducing reactive oxygen species production, and improving catalase activity. Furthermore, PEMFs preserved the mitochondrial membrane potential and decreased caspase-3 activation and chromatin condensation. Mechanistically, PEMFs inhibited ERK phosphorylation and enhanced cAMP levels, CREB phosphorylation, and BDNF expression, pathways known to support neuronal survival and plasticity. In conclusion, these findings suggest that PEMFs modulate multiple stress response systems, promoting neuroprotection under oxidative and amyloidogenic conditions. Full article

We have previously demonstrated the ability of inhibitors of LSD1 and HDAC1 to block rod degeneration, preserve vision, maintain transcription of rod photoreceptor genes, and downregulate transcripts involved in cell death, gliosis, and inflammation in the mouse model of Retinitis Pigmentosa (RP), rd10. To extend our findings, we tested the hypothesis that this effect was due to altered chromatin structure by using a range of inhibitors of chromatin condensation to prevent photoreceptor degeneration in the rd10 mouse model. We used inhibitors for both G9A/GLP, which catalyzes methylation of H3K9, and EZH2, which catalyzes trimethylation of H3K27, and compared them to the actions of inhibitors of LSD1 and HDAC. All the inhibitors are likely to decondense chromatin and all preserve, to different extents, retinas from degeneration in rd10 mice, but they act through different metabolic pathways. One group of inhibitors, modifiers for LSD1 and EZH2, demonstrate a high level of maintenance of rod-specific transcripts, activation of Ca²⁺ and Wnt signaling pathways with the inhibition of antigen processing and presentation, immune response, and microglia phagocytosis. Another group of inhibitors, modifiers for HDAC and G9A/GLP, work through upregulation of NGF-stimulated transcription, while downregulating genes belong to immune response, extracellular matrix, cholesterol signaling, and programmed cell death. Our results provide robust support for our hypothesis that inhibition of chromatin condensation can be sufficient to prevent rod death in rd10 mice. Full article

Understanding how the genome is organized into multi-level chromatin structures within cells and how these chromatin structures regulate gene transcription influencing animal development and human diseases has long been a major goal in genetics and cell biology. Recent evidence suggests that chromatin structure formation and remodeling is regulated not only by chromatin loop extrusion but also by phase-separated condensates. Here, we discuss recent findings on the mechanisms of chromatin organization mediated by phase separation, with a focus on the roles of phase-separated condensates in chromatin structural dysregulation in human diseases. Indeed, these mechanistic revelations herald promising therapeutic strategies targeting phase-separated condensates—leveraging their intrinsic biophysical susceptibilities to restore chromatin structure dysregulated by aberrant phase separation. Full article

Background: The pathogenesis of neuropsychiatric lupus erythematosus (NPSLE) is very complex and is associated with neuroinflammation and blood–brain barrier compromise. Experimental investigations of NPSLE have classically relied on spontaneous models. Recently, TLR7 agonist-induced lupus has been shown to exhibit similar neuropsychiatric manifestations to spontaneous ones. Cinnamon is a widespread spice and natural flavoring agent. It has been proven to modulate vascular endothelial tight junctions, neuroinflammation, and autoimmunity pathways, but it has never been tested in relation to lupus. Hypothesis/Purpose: In this pilot study, we aimed to explore the disease-modifying effect of Cinnamomum cassia on NPSLE in a TLR7 agonist-induced model. Study Design: An experimental design was followed in this study. Methods: Lupus was induced in C57BL/6J female mice via the direct application of imiquimod, a TLR7 agonist (5% imiquimod cream, 1.25 mg three times weekly), to the skin. Mice were divided into five groups (n = 8 per group): a sham group (S), a sham group supplemented with cinnamon (SC), an imiquimod-treated group (L), an imiquimod-treated group supplemented with cinnamon starting from induction (LC), and an imiquimod-treated group supplemented with cinnamon beginning two weeks prior to induction (CLC). This protocol was followed for six consecutive weeks. Cinnamomum cassia powder was administered orally at 200 mg/kg, 5 days per week. Results: Behavioral alterations were significantly ameliorated in the CLC group compared to lupus mice. Neuronal shrinkage and nuclear chromatin condensation were visible in the hippocampal cornu ammonis and dentate gyrus zones of lupus mice, with an increased expression of TLR7 and NLRP3, versus significantly less neurodegeneration and TLR7 and NLRP3 expression in the CLC group. In addition, the expression of the blood–brain barrier endothelial cell tight junction proteins claudin-1, occludin, and ZO-1 was abnormally modified in lupus mice and was restored in the CLC group. Moreover, while the cell–cell border delocalization of claudin-1 was documented in cultured blood–brain barrier endothelial cells treated with the plasma of lupus mice to a punctate intracytoplasmic fluorescence pattern, only cells treated with the plasma of the CLC group exhibited a complete reversal of this redistribution of claudin-1. Finally, cinnamaldehyde seemed to interact with TLR7 at multiple sites. Conclusions:Cinnamomum cassia seems to alleviate the pathogenesis of NPSLE. Supplementation with Cinnamomum cassia could be of great interest to modulate the activity and severity of the disease. Full article

Cervical cancer remains a significant global health concern, causing more than 300,000 deaths annually. Erythrina velutina, a tree native to north-eastern Brazil, contains bioactive alkaloids with potential anticancer properties. This study aimed to characterize the alkaloid-enriched fraction of Erythrina velutina leaves and investigate the effects of the alkaloid erythraline on apoptosis and cell cycle in SiHa cervical cancer cells. Using Gas Chromatography–Mass Spectrometry (GC-MS), six alkaloids, including erythraline, were identified. Cytotoxicity was assessed through proliferation assays on SiHa cells and peripheral blood mononuclear cells (PBMCs). Apoptosis and cell cycle analyses were performed using flow cytometry, and in silico virtual screening identified potential protein targets of erythraline. Erythraline showed time- and concentration-dependent inhibitory effects on SiHa cell proliferation, with significant cytotoxicity observed at 50 µg/mL. Morphological changes, chromatin condensation, and increased apoptotic cell percentages confirmed the induction of caspase-independent apoptosis. Erythraline also induced G2/M cell cycle arrest, with 22% of cells in the G2/M phase compared with 7.25% in the untreated controls. In silico analysis identified polyamine oxidase, pyruvate kinase M2, and tankyrase as potential targets that contribute to the antitumor activity of erythraline. These findings suggest that erythraline is a promising candidate for anticancer therapy, warranting further investigation. Full article

The carnivorous plant Sarracenia purpurea has been traditionally used in various ethnobotanical applications, including treatments for type 2 diabetes and tuberculosis-like symptoms. This study investigates the cytotoxic effects of S. purpurea root extract (Sp-R) on human non-small-cell lung cancer (NSCLC) cell lines, including H1975, H838, and A549, focusing on its impact on cell survival, apoptosis, proliferation, and migration. Additionally, its ability to inhibit the single-stranded DNA-binding activity of human RPA32 (huRPA32), a key protein in DNA replication, was evaluated. Extracts from different plant parts (leaf, stem, and root) were prepared using various solvents (water, methanol, ethanol, and acetone) and screened for apoptosis-inducing potential using the chromatin condensation assay. Among these, the acetone-extracted root fraction (Sp-R-A) exhibited the most potent pro-apoptotic effects. The MTT assay demonstrated a dose-dependent cytotoxic effect on NSCLC cells, with IC₅₀ values of 33.74 μg/mL for H1975, 60.79 μg/mL for H838, and 66.52 μg/mL for A549. Migration and clonogenic assays further revealed that Sp-R-A significantly inhibited cancer cell migration and colony formation in a dose-dependent manner. Moreover, Sp-R-A enhanced apoptosis when combined with the EGFR inhibitor afatinib, suggesting a potential synergistic effect. The electrophoretic mobility shift assay confirmed that Sp-R-A significantly inhibited the DNA-binding activity of huRPA32, with an IC₅₀ of 13.6 μg/mL. AlphaFold structural prediction and molecular docking studies indicated that major bioactive compounds in S. purpurea, including α-amyrin, ursolic acid, and betulinaldehyde, strongly interact with the DNA-binding domain of huRPA32, potentially contributing to its inhibitory effect. Overall, these findings suggest that huRPA32 is a potential molecular target of Sp-R-A and the anticancer potential of S. purpurea root extract against NSCLC is highlighted, supporting further investigation into its therapeutic applications. Full article

Over the years, caloric intake has remained a subject of profound scrutiny. Within the scientific community, there has been rigorous debate to ascertain which path is most ideal for enhancing quality of life and extending the human lifespan. Caloric restriction has been shown to be a promising contributor towards longevity and delaying the onset of age-related diseases. This diet consists of a reduction in caloric intake while maintaining essential energy and nutritional requirements to achieve optimal health while avoiding malnutrition. However, the effects of this nutritional regimen on male reproductive health have not yet been comprehensively studied. Nevertheless, such a complex process will certainly be regulated by a variety of metabolic sensors, likely sirtuins. Evidence has been gathered regarding this group of enzymes, and their ability to regulate processes such as chromatin condensation, the cell cycle, insulin signaling, and glucose and lipid metabolism, among many others. Concerning testicular function and male fertility, sirtuins can modulate certain metabolic processes through their interaction with the hypothalamic–pituitary–gonadal axis and mitochondrial dynamics, among many others, which remain largely unexplored. This review explores the impact of caloric restriction on male fertility, highlighting the emerging role of sirtuins as key regulators of male reproductive health through their influence on cellular metabolism. Full article

Human papillomavirus (HPV) 16 is transported in a retrograde fashion from the cell surface to the Golgi apparatus. Prior to mitosis, the virus loses association with the Golgi and, following nuclear envelope breakdown, is found associated with the condensed mitotic chromatin. The intervening steps have not been well defined. It was previously demonstrated that the virus is transported to the mitotic chromosomes in vesicles. Here, we describe the role of the endoplasmic reticulum (ER) in the post-Golgi trafficking and the importance of the ER-generated coat protein complex II (COPII) anterograde trafficking pathway in HPV infection. HPV pseudovirus (PsV) colocalized with COPII components and silencing of this pathway inhibited HPV infection. Additionally, the inner COPII coat protein, Sec24b, could be biochemically isolated in association with HPV capsid proteins. This study provides insight into the mechanism of post-Golgi HPV trafficking. Full article

Genomic sequences that form three-stranded triplexes (TPXs) under physiological conditions (called T-flipons) play an important role in defining DNA nucleosome-free regions (NFRs). Within these NFRs, other flipon types can cycle conformations to actuate gene expression. The transcripts read from the NFR form condensates that engage proteins and small RNAs. The helicases bound then trigger RNA polymerase release by dissociating the 7SK ribonucleoprotein. The TPXs formed usually incorporate RNA as the third strand. TPXs made only from DNA arise mostly during DNA replication. Many small RNA types (sRNAs) and long noncoding (lncRNA) can direct TPX formation. TPXs made with circular RNAs have greater stability and specificity than those formed with linear RNAs. LncRNAs can affect local gene expression through TPX formation and transcriptional interference. The condensates seeded by lncRNAs are updated by feedback loops involving proteins and noncoding RNAs from the genes they regulate. Some lncRNAs also target distant loci in a sequence-specific manner. Overall, lncRNAs can rapidly evolve by adding or subtracting sequence motifs that modify the condensates they nucleate. LncRNAs show less sequence conservation than protein-coding sequences. TPXs formed by lncRNAs and sRNAs help place nucleosomes to restrict endogenous retroelement (ERE) expression. The silencing of EREs starts early in embryogenesis and is essential for bootstrapping development. Once the system is set, EREs play a different role, with a notable enrichment of Short Interspersed Nuclear Repeats (SINEs) in Enhancer–Promoter condensates. The highly programmable TPX-dependent processes create a chromaverse capable of many complexities. Full article

Background: Splenic B-cell lymphomas and leukaemias include hairy cell leukaemia, splenic marginal zone lymphoma, splenic diffuse red pulp small B-cell lymphoma, and splenic B-cell lymphoma/leukaemia with prominent nucleoli. The main diagnostic challenge is to differentiate between splenic B-cell lymphomas and leukaemias due to highly overlapping clinical, morphologic, and phenotypic features in the absence of splenectomies for diagnostic purposes. Case presentation: We describe a case of a 78-year-old woman who presented with weight loss and was subsequently found to have pancytopenia, lymphocytosis, and splenomegaly. Peripheral blood smear showed a homogenous population of small- to medium-sized lymphocytes having oval nuclei, condensed chromatin, and villous cytoplasmic projections. Bone marrow showed B-cell infiltrate in a predominantly intrasinusoidal pattern. Except for cyclin D1 and BRAF, the immunophenotype was similar to that of hairy cell leukaemia. This was further supported by the lack of BRAF p.V600E mutation by polymerase chain reaction. A diagnosis of splenic diffuse red pulp small B-cell lymphoma was thus favored based on the lack of cyclin D1 expression and pattern of infiltration in the bone marrow biopsy. Conclusions: Awareness of this infrequent clinical presentation and immunophenotype of splenic diffuse red pulp small B-cell lymphoma is crucial for diagnosis and devising appropriate therapeutic strategies for the patient. Full article

Mitochondria are the powerhouses of cells, also involved in ROS (reactive oxygen species) generation and cellular death regulation. Thus, several diseases are associated with mitochondrial impairment, including cardiovascular disorders (CVDs). Since CVDs are currently the leading cause of death worldwide, it is very important to evaluate targeting mitochondrial effectors in clinical treatment protocols. Hence, in the present study, antimycin A and rotenone, established inhibitors of the mitochondrial electron transfer chain, were shown to halt apoptotic death induced by curcumin (50 μM) and sorbitol (0.5 M), in H9c2 cardiac cells. In particular, immunoblotting analysis revealed that they totally abolished PARP [poly(ADP-ribose) polymerase] proteolysis, under these conditions. This finding was accompanied by an enhancement of cell viability, recovery of mitochondria networks’ integrity, suppression of cytochrome c release into the cytoplasm, and reversal of chromatin condensation. Chelating extracellular calcium (with EGTA) further enhanced the beneficial impact of antimycin A and rotenone on curcumin- or sorbitol-treated H9c2 cells viability. Of interest, the phosphorylation of eIF2α, indicative of the onset of the pro-survival Integrated Stress Response (IRS), was sustained under these conditions. Overall, our data highlight the anti-apoptotic effect of these compounds, unmasking their potential as mediators in novel therapeutic interventions against mitochondria-associated cardiac dysfunction. Full article

A20/Tnfaip3, an early NF-κB response gene and key negative regulator of NF-κB signaling, suppresses proinflammatory responses. Its ubiquitinase and deubiquitinase activities mediate proteasomal degradation within the NF-κB pathway. This study investigated the involvement of A20 signaling alterations in podocytes in the development of kidney injury. The phenotypes of A20Δpodocyte (podocyte-specific knockout of A20) mice were compared with those of control mice at 6 months of age to identify spontaneous changes in kidney function. A20Δpodocyte mice presented elevated serum urea nitrogen and creatinine levels, along with increased accumulation of inflammatory cells—neutrophils and macrophages—within the glomeruli. Additionally, A20Δpodocyte mice displayed significant podocyte loss. Ultrastructural analysis of A20 podocyte-knockout mouse glomeruli revealed hypocellularity of the glomerular tuft, expansion of the extracellular matrix, podocytopenia associated with foot process effacement, karyopyknosis, micronuclei, and podocyte detachment. In addition to podocyte death, we also observed damage to intracapillary endothelial cells with vacuolation of the cytoplasm and condensation of nuclear chromatin. A20 expression downregulation and CRISPR-Cas9 genome editing targeting A20 in a podocyte cell line confirmed these findings in vitro, highlighting the significant contribution of A20 activity in podocytes to glomerular injury pathogenesis. Finally, we analyzed TNFAIP3 transcription levels alongside genes involved in apoptosis, anoikis, NF-κB regulation, and cell attachment in glomerular and tubular compartments of kidney biopsies of patients with various renal diseases. Full article