Search Results (662)

Telomeres are terminal regions of chromosomes that protect and stabilize chromosome structures. Telomeres are usually composed of specific DNA repeats (motifs) that are maintained by telomerase and a complex of specific proteins. Telomeric DNA sequences are generally highly conserved throughout the evolution of different groups of eukaryotes. The most common motif in insects is TTAGG, but it is not universal, including in the large order Hemiptera. In particular, several derived telomeric motifs were identified in this order by analyzing chromosome-level genome assemblies or by FISH screening the chromosomes of target species. Here, we analyzed chromosome-level genome assemblies of 16 species from three hemipteran suborders, including Sternorrhyncha (Coccoidea: Planococcus citri, Acanthococcus lagerstroemiae, and Trionymus diminutus; Aphidoidea: Tuberolachnus salignus, Metopolophium dirhodum, Rhopalosiphum padi, and Schizaphis graminum), Auhenorrhyncha (Cicadomorpha: Allygus modestus, Arthaldeus pascuellus, Aphrophora alni, Cicadella viridis, Empoasca decipiens, and Ribautiana ulmi), and Heteroptera (Gerromorpha: Gerris lacustris; Pentatomomorpha: Aradus depressus and A. truncatus). In addition, scaffold-level genome assemblies of three more species of Heteroptera (Gerromorpha: Gerris buenoi, Microvelia longipes, and Hermatobates lingyangjiaoensis) were examined. The presumably ancestral insect motif TTAGG was found at the ends of chromosomes of all species studied using chromosome-level genome assembly analysis, with four exceptions. In Aphrophora alni, we detected sequences of 4 bp repeats of TGAC, which were tentatively identified as a telomeric motif. In Gerris lacustris, from the basal true bug infraorder Gerromorpha, we found a 10 bp motif TTAGAGGTGG, previously unknown not only in Heteroptera or Hemiptera but also in Arthropoda in general. Blast screening of the scaffold-level assemblies showed that TTAGAGGTGG is also likely to be a telomeric motif in G. buenoi and Microvelia. longipes, while the results obtained for H. lingyangjiaoensis were inconclusive. In A. depressus and A. truncatus from the basal for Pentatomomorpha family Aradidae, we found a 10 bp motif TTAGGGATGG. While the available data allowed us to present two alternative hypotheses about the evolution of telomeric motifs in Heteroptera, further data are needed to verify them, especially for the yet unstudied basal infraorders Enicocephalomorpha, Dipsocoromorpha, and Leptopodomorpha. Full article

Gingival inflammation compromises the integrity of the gingival epithelium and the underlying tissues, highlighting the need for adjuvant therapies with immunomodulatory and healing properties. Casearia sylvestris, a medicinal plant known as guaçatonga, is traditionally used to treat inflammatory lesions. This study aimed to investigate the effects of C. sylvestris on the synthesis of pro- and anti-inflammatory, proteolytic, and antioxidant molecules and on wound healing in epithelial cells. A human telomerase-immortalized gingival keratinocyte cell line (TIGKs) was used, and cells were exposed to Escherichia coli lipopolysaccharide (LPS) in the presence and absence of C. sylvestris extract, its diterpene-concentrated fraction, and its clerodane diterpene casearin J for 24 h and 48 h. Gene expression and protein synthesis were analyzed by RT-qPCR and ELISA, respectively. Nitric oxide (NO) and NF-κB activation were analyzed by Griess reaction and immunofluorescence, respectively. Additionally, cell viability was evaluated by alamarBlue^® assay, and an automated scratch assay was used for wound healing. LPS significantly increased the expression of cytokines (TNF-α, IL-1β, IL-6, IL-8, IL-10, IL-17), proteases (MMP-1 and MMP-13), iNOS as well as NO synthesis, and triggered NF-κB nuclear translocation. It also reduced IL-4 expression, cell viability, and cellular wound repopulation. Treatment with C. sylvestris derivatives significantly abrogated all aforementioned LPS-induced effects by 80–100%. Furthermore, even at higher concentrations, C. sylvestris did not affect cell viability, thus proving the safety of its derivatives. C. sylvestris exerts anti-inflammatory, antiproteolytic, and antioxidant effects on gingival keratinocytes, highlighting its potential as a valuable adjunct in the prevention and treatment of periodontal diseases. Full article

During carcinogenesis, cells must acquire a telomere maintenance mechanism in order to avoid telomere shortening-induced replicative senescence. While most tumors activate telomerase, a minority of them employ a recombinational mechanism called Alternative Lengthening of Telomeres (ALT). One of the most investigated features is the association between ALT and ATRX mutations, since this has been shown to be the gene with the highest rate of mutations among ALT tumors. However, most of these studies, and in particular, mechanistic studies in vitro, have been carried out on mesenchymal tumors (sarcomas). In the present study, using genomic and expression data from the DepMap portal, we identified several non-mesenchymal ALT cell lines, and we compared the incidence of ATRX and other gene mutations between ALT cell lines of different origins (mesenchymal, neural, epithelial, hematopoietic). We confirmed that ATRX is frequently mutated in mesenchymal and neural ALT cell lines but not in epithelial ones. Our results showed that mutations of ATRX or other proteins involved in the maintenance of telomere integrity are needed for ALT activation in all cell types, and ATRX is preferentially mutated in mesenchymal ALT cells. Besides a more precise interpretation of the role of ATRX loss in ALT establishment, we proposed a model in which mutation of this gene impairs differentiation in mesenchymal and neural cells (but not in epithelial ones). Therefore, we explained the high incidence of ATRX mutations in mesenchymal and neural tumors with the fact that they both trigger ALT and impair differentiation, thus promoting two steps at once in the process of carcinogenesis. Full article

Nerve tissue damage is an unsolved problem in modern neurology and neurosurgery, which prompts the need to search for approaches to stimulate neuroprotection and regeneration of neural tissue. Earlier we have shown that the secretome of human mesenchymal stromal cells (MSCs) stimulates rat survival, reduces the severity of neurological deficits, and decreases the volume of brain damage in a hemorrhagic stroke model. A significant disadvantage of using the MSC secretome is the need to concentrate it (at least 5–10 fold) to achieve appreciable pharmacological activity. This increases the cost of obtaining clinically applicable amounts of secretome and slows down the clinical translation of this technology. Here, we created a number of genetically modified human MSC cultures, including immortalized MSCs and those with hyperexpression of brain-derived neurotrophic factor (BDNF) and urokinase-type plasminogen activator (uPA) and with suppressed expression of Von Hippel–Lindau tumor suppressor (VHL), and we evaluated the pharmacological activity of their secretomes in a model of intracerebral hemorrhage (ICH) in rats. The secretome of MSCs immortalized by hyperexpression of the catalytic subunit of human telomerase (hTERT) revealed neuroprotective activity indistinguishable from that of primary MSC cultures, yet it still required 10-fold concentration to achieve neuroprotective efficacy. The secretome of MSC culture with combined hyperexpression of BDNF and uPA and suppressed expression of Von Hippel–Lindau tumor suppressor even without additional concentration reduced the severity of neurological disorders and decreased brain lesion volume in the ICH model. The secretomes of MSCs with separate overexpression of BDNF and uPA or suppression of VHL had no such effect or, on the contrary, revealed a toxic effect in the ICH model. Presumably, this may be due to an imbalance in the representation of individual growth factors in the secretome of genetically modified MSCs, which individually may lead to undesirable effects in damaged nervous tissue, such as increased permeability of the blood–brain barrier (under the influence of pro-angiogenic factors) or neural cell apoptosis (due to an excess of neurotrophic factors). The obtained data show that genetic modification of MSC cultures can enhance or alter the therapeutic activity of their secretomes, which can be used in the creation of promising sources of biopharmaceutical substances. Full article

Telomeres are repetitive DNA sequences at the ends of chromosomes that protect against genomic instability and prevent unwanted DNA damage responses. In most somatic cells, telomeres progressively shorten with each division, limiting cellular lifespan. However, cancer cells bypass this limitation by activating telomerase or the alternative lengthening of telomeres, enabling unchecked proliferation and tumor progression. This review examines the molecular mechanisms underlying telomere maintenance and their intricate relationship with DNA repair pathways. We discuss how telomere-associated proteins regulate genomic stability and explore therapeutic strategies targeting telomerase and alternative lengthening of telomeres. Challenges such as resistance mechanisms and off-target effects are also considered, highlighting the need for precision approaches in telomere-based cancer therapies. Full article

Background/Objectives: Cxbladder^® Triage Plus is a multimodal urinary biomarker assay that combines reverse transcription-quantitative analysis of five mRNA targets and droplet-digital polymerase chain reaction (ddPCR) analysis of six DNA single-nucleotide variants (SNVs) from two genes (fibroblast growth factor receptor 3 (FGFR3) and telomerase reverse transcriptase (TERT)) to provide risk stratification for urothelial carcinoma (UC) in patients with hematuria. This study evaluated the analytical validity of Triage Plus. Methods: The development dataset used urine samples from patients with microhematuria or gross hematuria that were previously stabilized with Cxbladder solution. Triage Plus was evaluated for predicted performance, analytical criteria (linearity, sensitivity, specificity, accuracy, and precision), extraction efficiency, and inter-laboratory reproducibility. Results: The development dataset included 987 hematuria samples. Compared with cystoscopy (standard of care), Triage Plus had a predicted sensitivity of 93.6%, specificity of 90.8%, positive predictive value (PPV) of 46.5%, negative predictive value of 99.4%, and test-negative rate of 84.1% (score threshold 0.15); the PPV increased to 74.6% for the 0.54 score threshold. For the individual FGFR3 and TERT SNVs, the limit of detection (analytical sensitivity) was a mutant-to-wild type DNA ratio of 1:440–1:1250 copies/mL. Intra- and inter-assay variance was low, while extraction efficiency was high. All other pre-specified analytical criteria (linearity, specificity, and accuracy) were met. Triage Plus showed good reproducibility (87.9% concordance between laboratories). Conclusions: Cxbladder Triage Plus accurately and reproducibly detected FGFR3 and TERT SNVs and, in combination with mRNA expression, provides a non-invasive, highly sensitive, and reproducible tool that aids in risk stratification of patients with hematuria. Full article

Hepatocellular carcinoma (HCC) is a major cause of cancer-related mortality worldwide, but its molecular drivers remain underexplored in Latin American populations. This study investigated the prevalence, co-occurrence, and tissue distribution of somatic mutations in the TERT promoter (C228T/C250T) and CTNNB1 exon 3, as well as TERT gene expression, in liver tissues from Brazilian patients. A total of 85 samples (42 HCC, 21 cirrhosis, and 22 hepatitis) were analysed using Sanger sequencing and RT-qPCR. TERT promoter mutations were detected in 47.6% of HCC tissues, including C228T (45.2%) and C250T (2.4%), and were also present in 19% of cirrhotic tissues but absent in hepatitis samples, supporting their emergence in early hepatocarcinogenesis. CTNNB1 exon 3 mutations occurred in 17.2% of HCCs and significantly co-occurred with TERTp mutations (66.7%, p = 0.0485), although the number of CTNNB1-mutated cases was limited. TERT expression was significantly upregulated in HCC tissues regardless of mutation status (p < 0.001). This is the first study to characterise these mutations in Brazilian HCC patients, highlighting the C228T mutation as a promising biomarker for early detection and molecular surveillance in cirrhotic individuals. Despite the genetic admixture of the studied population, the mutational patterns were comparable to those reported in more homogeneous populations, reinforcing the global relevance of these molecular alterations. Full article

Aging is a complex biological process characterized by the progressive accumulation of cellular and molecular damage, leading to functional decline and increased susceptibility to age-related diseases. Central to this process is cellular senescence, a state of irreversible cell cycle arrest that acts as both a protective mechanism against tumorigenesis and a contributor to tissue degeneration. Herein, we explore the genetic and molecular mechanisms underlying aging, with a focus on telomere dynamics, the Klotho gene, angiotensin-converting enzyme (ACE), and the NF-κB pathway. Telomeres, which serve as protective caps at chromosome ends, shorten with each cell division, leading to replicative senescence, while the enzyme telomerase plays a pivotal role in maintaining telomere length and cellular longevity. The Klotho gene encoding for an aging suppressor influences insulin/IGF-1 signaling and has antioxidant properties that protect against oxidative stress. ACE, through its dual role in regulating blood pressure and degrading amyloid-beta, impacts longevity and age-related pathologies. The NF-κB pathway drives chronic inflammation or “inflammaging,” contributing to the onset of age-related diseases. Understanding these pathways offers promising avenues for therapeutic interventions to extend health span and lifespan. Targeting mechanisms such as telomerase activation, Klotho supplementation, ACE inhibition, and NF-κB modulation hold potential for combating the detrimental effects of aging and promoting healthier aging in the population. Full article

Background: This study investigates the effects of a tocotrienol-enriched drink on oxidative damage and genomic stability in older adults over a 6-month period. Methods: A total of 67 participants (27 males and 40 females, mean age 60.45 ± 5.75 years) were enrolled in this double-blinded, two-arm, parallel randomized controlled trial. Baseline, mid-point, and end-point assessments were conducted to monitor various health parameters. Significant Group × Time interaction effects were observed for several key outcomes. Results: Group A demonstrated significantly better improvements in QOL-Psychological (p = 0.014, Partial Eta Squared = 0.153), suggesting a beneficial impact of tocotrienol supplementation on mental well-being. Additionally, Group A showed more favorable trends in TNF-α (p = 0.04), T-SOD (p = 0.04), catalase (p = 0.02), and telomerase (p = 0.02), suggesting potential antioxidant and genomic stability improvements over time. Conclusions: In a nutshell, tocotrienol supplementation may exert beneficial effects on psychological well-being, oxidative stress modulation, and genomic stability in aging populations. Full article

Background: Telomerase activity is a cancer hallmark, and hTERT is the rate-limiting catalytic subunit of telomerase. In human papillomavirus type 16 E6 (16E6)-expressing epithelial cells, NFX1-123 augments and is required for full hTERT expression, leading to a growth advantage. However, no studies have investigated the role of NFX1-123 in telomerase activity regulation in HPV-associated cancers. Methods: We knocked out NFX1-123 in CaSki cells (CaSki KO) and performed single-cell RNA sequencing to determine mRNA alterations affected by reduced NFX1-123. Results: In CaSki KO cells, there were three cell clusters based on gene expression, each associated with different enriched biological processes. When pooled and compared with control cells, CaSki KO cells had 1661 decreased and 565 increased mRNAs involving RNA regulation, cell cycle and division, chromatin regulation, and carcinogenesis processes and pathways. CENP-F, a cell cycle and chromosome segregation gene increased in cervical cancers, was among 10 genes with the greatest decrease in mRNA expression in CaSki KO cells. CaSki and SiHa cells with either reduced NFX1-123 or knocked down HPV 16 E6 and E7, demonstrated reduced hTERT, CENP-F, and telomerase activity, and when both NFX1-123 and HPV 16 E6 and E7 were decreased, hTERT and telomerase activity fell further. Finally, hTERT and CENP-F were increased in cervical cancer primary tumors and in HPV-positive head and neck cancer primary tumors in the TCGA database. Conclusions: These findings highlight the shared role that NFX1-123 has with HPV 16 oncogenes in driving and maintaining RNA, cell cycle, and carcinogenesis pathways, and specifically regulating hTERT, telomerase, and CENP-F. Full article

Telomere attrition is a hallmark of cellular aging, influenced by oxidative stress, chronic inflammation, and metabolic dysregulation. Emerging evidence suggests that dietary patterns rich in plant-based, minimally processed foods may influence telomere dynamics, potentially extending healthspan. This narrative review synthesizes current literature on the molecular mechanisms by which specific nutrients—such as antioxidants, polyphenols, omega-3 fatty acids, and methyl donors—affect telomere length and telomerase activity. Conversely, high consumption of ultra-processed foods (UPFs) has been associated with accelerated telomere shortening and dysfunction, likely due to increased oxidative stress, inflammation, and nutrient deficiencies. We propose a tiered dietary intervention model including preventive, therapeutic, and regenerative phases, tailored to individual aging trajectories and physiological statuses. This model emphasizes the consumption of whole plant foods, functional bioactives, and the reduction of UPFs to preserve telomere integrity. Implementing such dietary strategies may offer a viable approach to mitigate age-related cellular decline and promote healthy aging. Full article

Objectives: A randomized, double-blind, placebo-controlled intervention study aimed to evaluate whether hawthorn fruit (HF) supplementation can influence facial skin phenotypes and leukocyte telomere length (TL) and whether these effects differ by genetic polymorphisms related to TL. Participants/Methods: Among 41 male and female adults aged 25–75 years who participated in the study, 36 completed initial and follow-up examinations over 6 months. The HF supplementation group (n = 17) was instructed to take a powdered HF supplement (900 mg/day), while controls (n = 19) were to take a cornstarch placebo (900 mg/day). Facial skin phenotypes, including pigmentation, pores, hydration, wrinkles, and elasticity, were measured before and after the intervention, and changes in these phenotype scores were calculated. Sequencing of telomerase reverse transcriptase (TERT) polymorphisms, such as rs7705526 (C>A) and rs2853669 (A>G), was conducted. Results: The HF supplementation group exhibited significantly improved hydration scores compared to the control group; the mean changes (follow-up measure—baseline measure) [standard deviation] in hydration scores over 6 months were 1.71 [8.18] and −3.00 [8.42] for the supplementation group and control group, respectively (p < 0.05) (Cohen’s d = 0.57). However, changes in other phenotypes and leukocyte TL were similar between groups. The genotype-specific analysis revealed that the improvement of hydration state was most noticeable among carriers with the CC genotype of rs7705526 (p < 0.05) (Cohen’s d = 1.50) and that the HF supplementation group exhibited reduced wrinkle scores while the control group showed increased scores among carriers of the AA genotype of rs2853669 (p < 0.05) (Cohen’s d = 1.40). In correlation analysis for all participants, hydration scores were positively correlated with leukocyte TL (Spearman correlation coefficient: 0.36; p < 0.05). Conclusions: These findings suggest that HF consumption may have potential anti-skin-aging effects. Future studies may need to elucidate the biological mechanisms underlying these effects. Full article

The nucleoprotein structures known as telomeres provide genomic integrity by protecting the ends of chromosomes. Tumorigenesis is associated with alterations in telomere function and stability. This narrative review provides evidence of the potential prognostic value of telomere length and telomerase in leukemias. On the one hand, oxidative stress and mitochondrial dysfunction can accelerate telomere shortening, leading to higher susceptibility and the progression of leukemia. On the other hand, cytogenetic alterations (such as gene fusions and chromosomal abnormalities) and genomic complexity can result from checkpoint dysregulation, the induction of the DNA damage response (DDR), and defective repair signaling at telomeres. This review thoroughly outlines the ways by which telomere dysfunction can play a key role in the development and progression of four primary leukemias, including chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), and acute leukemias of myeloid or lymphoid origin, highlighting the potential prognostic value of telomere length in this field. However, telomerase, which is highly active in leukemias, can prevent the rate of telomere attrition. In line with this, leukemia cells can proliferate, suggesting telomerase as a promising therapeutic target in leukemias. For this reason, telomerase-based immunotherapy is analyzed in the fight against leukemias, leveraging the immune system to eliminate leukemia cells with uncontrolled proliferation. Full article

Background/Objectives: The methylation of the hypermethylated oncological region (THOR) of human telomerase reverse transcriptase (hTERT) may forecast tumour aggressiveness. This pilot study aimed to evaluate THOR methylation as a potential biomarker for recurrence/malignant transformation in salivary gland pleomorphic adenomas (PA). Methods: THOR methylation was assessed by quantitative pyrosequencing in 96 parotid tissue samples (benign and malignant), including non-neoplastic parotid tissue, PA, recurrent PA (rPA), and carcinomas, along with their adjacent tissues. TERT promoter mutations (TPMs) were analysed by Sanger sequencing. Results: THOR methylation significantly differed across the seven groups. Malignant tissues showed higher THOR methylation than non-neoplastic tissues, whereas benign tumours showed no significant difference from non-neoplastic tissue. THOR methylation in rPA was closer to carcinoma than to normal tissue, similar in rPA and tissues adjacent to rPA, and higher in tissues adjacent to carcinomas than in non-neoplastic tissues. A subset of PA-adjacent tissues showed epigenetic alterations, suggesting an increased risk of recurrence or malignant transformation (5–15%). No TPMs were detected. Conclusions: THOR methylation may add information to differentiate normal from carcinogenic tissues and, as such, may be included in a biomarkers panel. Epigenetic alterations in PA-adjacent tissues with normal histology highlight the need for improved diagnostic markers. Full article

The conserved and essential Cdc13/CTC1-Stn1-Ten1 telomeric complex (CST) ensures chromosome stability by protecting telomere ends and regulating telomerase accessibility. In a recent study, we uncovered mutants of the S. cerevisiae CST, in which damage was sensed by the two major G2/M spindle checkpoints (one is Bub2-dependent and the other one Mad2-dependent), as well as the major G2/M DNA damage checkpoint (Mec1-dependent). In this study, we found, by fluorescence microscopy, that the stability of the mitotic tubulin spindle was profoundly affected in the best-studied of these mutants, stn1-sz2. Additional data from genetic analyses suggested the potential involvement of Stu1 and Stu2, as well as Slk19, in these defects. Throughout this study, we compared the phenotypes of stn1-sz2 with those of cdc13-1, the best-studied CST mutant, which also serves as a prototype of telomere-damage-characterized CST mutants. We propose that stn1-sz2 represents the prototype of cst mutants characterized by tubulin spindle damage. These newly described phenotypes potentially represent the basis for identifying new functions of the CST telomeric complex. These functions might consist of ensuring correct chromosome segregation through the stabilization of the mitotic spindle. Full article