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Results for “Telomerase”

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PubMed2026

Progress on the telomere-telomerase system in planarian neoblasts homeostasis and regeneration.

Planarians are flatworms with remarkable regenerative abilities, and their adult pluripotent stem cells, known as neoblasts, serve as the foundation for this regeneration. Neoblasts can rapidly migrate, proliferate, and undergo directed differentiation following tissue injury to complete regeneration. Telomeres are located at the ends of eukaryotic chromosomes and play a core role in maintaining chromosomal integrity. With each cell division, telomeres shorten. Telomerase is a reverse transcriptase that compensates for telomere loss during cell division by extending telomeric repeats. The telomere-telomerase system is one of the important mechanisms for maintaining stem cell homeostasis. As adult pluripotent stem cells of planarians, neoblasts are required to maintain a dynamic balance between high-frequency cell division and multilineage differentiation. The maintenance of their long-term proliferative capacity and genomic stability may depend on the precise regulation of the telomere-telomerase system. Thus, this system represents a critical entry point for understanding the remarkable regenerative ability of planarians. Integrating recent progress in regeneration, neoblast regulation, and the telomere-telomerase system, we systematically summarize the emerging evidence for telomere- telomerase involvement in neoblast homeostasis and regeneration. We aim to provide insights for research in regenerative medicine, stem cell regulation, and neural injury repair.

Animals↗

PubMed2026

MYDGF as a telomerase activator and therapeutic target for osteoarthritis.

Osteoarthritis (OA) involves progressive cartilage breakdown. This is driven by impaired chondrocyte function and an imbalance in the extracellular matrix homeostasis. However, the key upstream regulators that maintain healthy chondrocytes are still not fully known. Here, we report that myeloid-derived growth factor (MYDGF) is a novel regulator of telomerase activity and is critical for cartilage health. Using a genome-wide CRISPR-Cas9 screen with a TERT reporter system, MYDGF was identified as a strong positive regulator of telomerase. Functional studies confirmed that MYDGF positively regulates TERT expression and telomerase activity in both HeLa and ATDC5 cells. In a mouse surgical destabilization of the medial meniscus (DMM) OA model, MYDGF knockout (KO) mice exhibited more severe cartilage damage. Conversely, delivering MYDGF into the knee joint using AAV virus partially alleviated cartilage injury. Transcriptome profiling revealed that MYDGF-deficient chondrocytes exhibit downregulated key pathways involved in matrix building and upregulated inflammatory signals, indicating a shift in cell state. In summary, our work establishes MYDGF as a key upstream factor for both telomerase and cartilage matrix homeostasis remodeling. It connects telomerase function to chondrocyte health. These findings also highlight MYDGF as a promising new target for treating osteoarthritis.

Cartilage degeneration↗

PubMed2025

Epitalon increases telomere length in human cell lines through telomerase upregulation or ALT activity.

Epitalon, a naturally occurring tetrapeptide, is known for its anti-aging effects on mammalian cells. This happens through the induction of telomerase enzyme activity, resulting in the extension of telomere length. A strong link exists between telomere length and aging-related diseases. Therefore, telomeres are considered to be one of the biomarkers of aging, and increasing or maintaining telomere length may contribute to healthy aging and longevity. Epitalon has been the subject of several anti-aging studies however, quantitative data on the biomolecular pathway leading to telomere length increase, hTERT mRNA expression, telomerase enzyme activity, and ALT activation have not been extensively studied in different cell types. In this article, the breast cancer cell lines 21NT, BT474, and normal epithelial and fibroblast cells were treated with epitalon then DNA, RNA, and proteins were extracted. qPCR and Immunofluorescence analysis demonstrated dose-dependent telomere length extension in normal cells through hTERT and telomerase upregulation. In cancer cells, significant telomere length extension also occurred through ALT (Alternative Lengthening of Telomeres) activation. Only a minor increase in ALT activity was observed in Normal cells, thereby showing that it was specific to cancer cells. Our data suggests that epitalon can extend telomere length in normal healthy mammalian cells through the upregulation of hTERT mRNA expression and telomerase enzyme activity.

Humans↗

PubMed2025

Subtelomeric elements provide stability to short telomeres in telomerase-negative cells of the budding yeast Naumovozyma castellii.

Telomerase plays an important role in sustaining eukaryotic linear chromosomes, as elongation of telomeres is needed to counterbalance the shortening occurring in each replication round. Nevertheless, in telomerase-deficient cells, Alternative Lengthening of Telomeres (ALT) pathways can maintain telomeres by employing recombination-based mechanisms. In the budding yeast Naumovozyma castellii, effective activation of the ALT pathway leads to bypass of senescence and supports long-term growth. We found that telomere structures in N. castellii ALT cells are stably maintained at a shortened uniform length over extensive numbers of generations. This is correlated to the spreading of a subtelomeric sequence, TelKO element, to all telomeres. Genome sequencing of the wild-type strain revealed variants of the TelKO element, differing in their lengths, and separate ALT strains are maintained by spreading of distinct TelKO element variants. Although short uniform telomere structures are predominant, sporadic telomere lengthening events occur by addition of long repeated arrays of TelKO elements. The telomere-binding protein Rap1 can bind to TelKO sequences in vitro, indicating a functional role of TelKO elements in providing stability to shortened ALT telomeres. Our results suggest that stable maintenance and telomere functionality may be achieved by incorporating the distal subtelomeric TelKO sequences into the telomeric chromatin cap.

Telomerase↗

PubMed2025

Non-canonical functions of DNMT3A in hematopoietic stem cells regulate telomerase activity and genome integrity.

DNMT3A is a critical regulator of hematopoietic stem cell (HSC) fate decisions and the most recurrently mutated gene in human clonal hematopoiesis (CH). DNMT3A is described as a DNA methyltransferase enzyme, but cells with DNMT3A loss of function show minor changes in DNA methylation that do not correlate with altered gene expression. To explore the possibility that Dnmt3a has DNA-methylation-independent functions in HSCs, we created an allelic series of mice with varying levels of DNA-methylation-impaired Dnmt3a. Clonal expansion of Dnmt3a-deficient HSCs was rescued by Dnmt3a proteins lacking DNA methylation capacity, suggesting that Dnmt3a has important non-canonical functions in HSCs. Dnmt3a-null HSCs can be transplanted indefinitely, implying the ability to circumvent mechanisms that limit the replicative lifespan of HSCs, such as telomere shortening. Dnmt3a-null HSCs show increased telomerase activity and sustain telomere length over serial transplantation, revealing a previously unidentified role for DNMT3A mutations in regulating HSC longevity that is unrelated to DNA methylation function.

Animals↗

PubMed2025

PUMA-induced apoptosis drives bone marrow failure and genomic instability in telomerase-deficient mice.

Bone marrow failure is a severe complication of human telomere biology disorders and predisposes individuals to secondary leukemia. A deeper understanding of this process could offer significant clinical benefits. Using a preclinical mouse model deficient in the RNA component of the telomerase (mTerc), we demonstrate that bone marrow failure results from excessive apoptosis, predominantly mediated by the pro-apoptotic p53 target PUMA. Genetic ablation of Puma alleviates hematological phenotypes and reduces the risk of lethal bone marrow failure while preserving genomic stability. Mechanistically, PUMA deficiency decreases the sensitivity of hematopoietic cells to lethal stressors, including critically short telomeres. As a consequence, reduced compensatory turnover of hematopoietic progenitors slows down telomere shortening at the population level, delays stem cell exhaustion, and diminishes the acquisition of somatic mutations - ultimately preventing neoplastic transformation. Elevated expression of both p53 and PUMA is also observed in the bone marrow from patients with telomere biology disorders. While apoptosis resistance is traditionally associated with malignant transformation, our findings provide evidence that selective inhibition of PUMA-mediated apoptosis may represent a viable therapeutic strategy to prevent or delay leukemic transformation in this patient population.

Animals↗

PubMed2026

Spinal low-grade ependymal tumors harboring telomerase reverse transcriptase promoter mutation and chromosome 7 gain with methylation profile of spinal subependymoma.

Spinal intramedullary tumors comprise a heterogeneous group of entities with diverse histopathological features, making their diagnosis particularly challenging. With the introduction of DNA methylation profiling, the underlying biological diversity of these tumors has been increasingly clarified and systematized; however, owing to the rarity of these tumors, case accumulation remains limited, and significant challenges persist. In this study, we identified two cases of spinal ependymal tumors exhibiting a methylation profile of spinal (SP-) subependymoma (SEPN). Both cases occurred in elderly patients and demonstrated circumscribed growth consistent with low-grade ependymal tumors; however, these tumors did not exhibit the typical histopathological features required for a diagnosis of SEPN in the 2021 WHO classification of central nervous system (CNS) tumors, showing indistinct cluster formation, an astrocytic immunohistochemical profile suggested by Olig2 expression, and relatively elevated Ki-67 labeling indices of 4.5% and 3.1%. At the molecular level, both cases harbored telomerase reverse transcriptase promoter mutations and whole chromosome 7 gain. On two-dimensional t-distributed stochastic neighbor embedding analysis, both clustered within the SP-SEPN methylation class at its periphery, with low classifier calibration scores (0.70 and 0.69). According to the current WHO classification, these cases are designated as low-grade ependymal tumors (CNS WHO grade 2) with methylation profile of SP-SEPN because they do not meet the essential WHO histopathological criteria. Ependymal tumors exhibiting a methylation profile consistent with SEPN, but discordant histopathological features have been increasingly recognized, and the appropriate classification of such tumors remains a subject of ongoing debate. These cases provide important insights into the histopathological diversity of ependymal tumors and contribute to establishing a more comprehensive and systematic classification of ependymal tumors.

Aged↗

PubMed2025

Predicting telomerase reverse transcriptase promoter mutation status in glioblastoma by whole-tumor multi-sequence magnetic resonance texture analysis.

OBJECTIVE: This study aimed to determine the feasibility of preoperative multi-sequence magnetic resonance texture analysis (MRTA) for predicting TERT promoter mutation status in IDH-wildtype glioblastoma (IDHwt GB). METHODS: The clinical and imaging data of 111 patients with IDHwt GB at our hospital between November 2018 and June 2023 were retrospectively analyzed as the training set, and those of 23 patients with IDHwt GB between July 2023 and November 2023 were interpreted as the validation set. We used molecular sequencing results to classify the training set into TERT promoter mutation and wildtype groups. Textural features of the whole-tumor volume were extracted, including T2-weighted imaging (T2WI), T2-fluid-attenuated inversion recovery, apparent diffusion coefficient (ADC) map, and contrast-enhanced T1-weighted imaging (CE-T1). All textural features were obtained using open-source pyradiomics. After feature selection, logistic regression was used to build prediction models, and a nomogram was generated. Finally, the model was validated using validation cohort. RESULTS: The CE-T1_Model (AUC 0.704) had a better predictive ability than the T2_Model (AUC 0.684) and ADC_Model (AUC 0.624). The MRI_Combined_Model (CE-T1, T2, and ADC texture features) (AUC 0.780) had a better predictive ability than the Clinical_Model (AUC 0.758). The Combined_Model (CE-T1, T2, ADC texture features, and clinical features) had the best predictive performance (AUC 0.871), with a sensitivity, specificity, and accuracy of 82.60 %, 83.30 %, and 80.18 %, respectively. The AUC, sensitivity, specificity, and accuracy in the validation cohort were 0.775, 86.70 %, 75.00 %, and 69.57 %, respectively. CONCLUSIONS: Whole-tumor multi-sequence MRTA can be used as non-invasive quantitative parameters to assist in the preoperative clinical prediction of TERT promoter mutation status in IDHwt GB.

Humans↗

PubMed2026

Twisting the End Game: How Telomere Chromatin Modifications Shape Telomere Maintenance.

Cell division inevitably shortens telomeric DNA owing to the end-replication problem. Eukaryotic chromosomes possess specialized telomere structures to maintain genomic stability. In most proliferative cells, telomerase adds telomeric repeats during S-phase. In differentiated cells where telomerase is silenced, telomeres shorten progressively, thereby compromising genomic integrity. Consequently, cancer cells universally activate alternative telomere maintenance mechanisms during malignant transformation: ~80% reactivate telomerase, while a portion of the rest rely on BIR (break-induced replication)-mediated homologous recombination-based ALT (alternative lengthening of telomeres). Although these mechanisms are stable once established, the initial determinants influencing a cancer cell's choice remain poorly understood. This review discusses recent molecular insights into how telomeric chromatin properties profoundly impact this choice. After briefly introducing telomere chromatin characteristics and key players in its maintenance and dynamics, we discuss the mechanisms by which cancer cells acquire distinct telomere replication capabilities. In particular, we present an in-depth analysis linking telomere heterochromatin status to ALT. Furthermore, based on recent advances, we propose a coupled feedforward loop model explaining how the ALT state becomes "locked in" once initiated. Finally, we offer novel perspectives on rational, telomere-centric therapeutic interventions for ALT-positive cancers, focusing on strategies designed to disrupt such feedforward loops by manipulating telomeric chromatin structure.

Humans↗

PubMed2025

Aberrant TERT expression: linking chronic inflammation to hepatocellular carcinoma†.

Telomerase reverse transcriptase (TERT), the catalytic enzyme component of telomerase, plays multiple roles in cellular biology. Its canonical function is primarily associated with telomere maintenance and genomic stability. In addition, several studies revealed critical non-canonical extra-telomeric functions of TERT in various cellular processes, including cell proliferation and survival, DNA damage response, transcription, signal transduction, and metabolic regulation, both in normal and in cancer cells. Notably, TERT is aberrantly upregulated in more than 80% of hepatocellular carcinoma (HCC) cases, making it an important target in liver cancer research. However, due to the diversity and complexity of TERT's functions in vivo, the precise mechanisms by which TERT contributes to the initiation and progression of HCC remain unclear. A recent study published in The Journal of Pathology using the Alb-Cre;TertTg mouse model and clinical HCC samples addresses the role of TERT in hepatocarcinogenesis. The study demonstrates that TERT promotes cell cycle progression and hepatocarcinogenesis by enhancing NF-κB promoter activity and facilitating the ubiquitination of p21. Notably, absence of functional p53 accelerates liver tumor development in TERT transgenic mice. These findings further underscore the critical role of TERT in inflammation-driven hepatocarcinogenesis and provide new insights into its underlying mechanisms. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Telomerase↗

PubMed2026

Non-telomeric function deficiency of TERT enhances pressure overload-induced mouse cardiac remodeling by activation of CNBP-mediated THBS3/ITGB1 pathway.

Recent studies show that telomerase reverse transcriptase (TERT) possesses important new biological functions in gene transcription regulation, signal transduction, tumorigenesis, vascular development and mitochondrial DNA protection independent of the maintenance of telomere length. In this study we investigated the role and mechanisms of TERT in regulating the gene expression and signal transduction during pressure overload-induced cardiac remodeling. The first-generation TERT knockout (Tert-/-) and wild-type littermate control (Tert+/+) male mice were subjected to transverse aortic constriction (TAC) surgery to establish a pressure overload-induced cardiac remodeling model. We showed that pressure overload significantly increased TERT expression in the hearts at 8 weeks after TAC, whereas TERT deficiency remarkably exacerbated pressure overload-induced cardiac dysfunction, cardiac hypertrophy and fibrosis, and reduced the survival rate of the mice. In contrast, TERT overexpression reversed phenylephrine (PE)-stimulated cardiomyocyte hypertrophy and fibrosis in neonatal rat ventricular myocytes (NRVMs). Ttranscriptomic and proteomic analyses revealed that extracellular matrix (ECM)-receptor interaction was a key Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway regulated by TERT in hemodynamic overload-induced cardiac remodeling. TERT knockdown greatly enhanced, while TERT overexpression inhibited the activation of the THBS3/ITGB1 signaling pathway, in which transcription factor cellular nucleic acid-binding protein (CNBP) played a pivotal mediating role by interacting with TERT. In conclusion, the non-telomeric function of TERT in gene transcription regulation and signaling transduction plays an important role during pressure overload-induced myocardial remodeling via modulating CNBP-mediated THBS3/ITGB1 signaling pathway, which provides new targets and strategies for the prevention and treatment of pressure overload-induced cardiac remodeling.

Animals↗

PubMed2024

Human PC4 supports telomere stability and viability in cells utilizing the alternative lengthening of telomeres mechanism.

Cancer cells with an activated Alternative Lengthening of Telomeres (ALT) mechanism elongate telomeres via homology-directed repair. Sustained telomeric replication stress is an essential trigger of ALT activity; however, it can lead to cell death if not properly restricted. By analyzing publicly available data from genome-wide CRISPR KO screenings, we have identified the multifunctional protein PC4 as a novel factor essential for ALT cell viability. Depletion of PC4 results in rapid ALT cell death, while telomerase-positive cells show minimal effects. PC4 depletion induces replication stress and telomere fragility primarily in ALT cells, and increases ALT activity. PC4 binds to telomeric DNA in cells, and its binding can be enhanced by telomeric replication stress. Finally, a mutant PC4 with partly impaired single stranded DNA binding activity is capable to localize to telomeres and suppress ALT activity and telomeric replication stress. We propose that PC4 supports ALT cell viability, at least partly, by averting telomere dysfunction. Further studies of PC4 interactions at ALT telomeres may hold promise for innovative therapies to eradicate ALT cancers.

Humans↗

PubMed2026

TERT promoter mutations and recurrence patterns in differentiated thyroid carcinoma.

Telomerase reverse transcriptase promoter mutations (TERT) are known prognostic factors associated with poor outcomes in differentiated thyroid carcinoma (DTC). We analyzed differences in DTC recurrence patterns over time according to TERT. A retrospective review was conducted on DTC patients who achieved remission after total thyroidectomy and/or radioactive iodine treatment at Samsung Medical Center between 1994 and 2004. The sites and patterns by time of recurrence in the patients were reviewed. In total, 367 patients with a median follow-up of 14 years (interquartile range, 12-17 years) were included. Recurrence occurred in 91 patients, wherein 56 had lymph node recurrence and 35 had either local or distant recurrence. TE RT and tumor size <2 cm were independent factors for recurrence in the Cox proportional hazards analysis. In cases of TERT-wild type (WT), the recurrence rate decreased significantly over time after diagnosis, whereas in TERT-mutant type (MT), a consistently high recurrence rate was observed. In the Kaplan-Meier analysis, TERT-MT exhibited a significantly poorer disease-free survival, with continuous recurrence over time, whereas in TERT-WT, the curve showed a gradual decline. Further analysis of the overall survival among the 91 patients revealed that TERT-MT was significantly associated with a higher risk of mortality, whereas TERT-WT exhibited a slowly decreasing curve. In conclusion, TERT-MT was a significant adverse prognostic factor wherein continuous recurrence necessitates long-term follow-up. For TERT-WT, the recurrence rate decreased compared to TERT-MT, and even in cases of recurrence, the treatment outcomes are favorable.

Humans↗

PubMed2026

Value of TERT promoter mutations for early outcomes in papillary thyroid cancer.

Telomerase reverse transcriptase (TERT) promoter mutations are associated with aggressive clinicopathological features of papillary thyroid cancer (PTC). However, their independent prognostic value remains unclear. This study aimed to evaluate the prognostic significance of TERT promoter mutations (TPMs) in predicting early treatment outcomes and event-free survival (EFS) in patients with PTC. We retrospectively analyzed a prospective cohort; patients underwent surgery at a single tertiary referral center between 2019 and 2022. Patients underwent thyroidectomy, selective postoperative radioactive iodine ablation, and levothyroxine suppression therapy. Propensity score matching (PSM, 1:1) was applied to adjust for baseline clinicopathological differences. Of 10,642 patients with available molecular data, 115 (1.1%) harbored TPMs. After PSM, 90 matched pairs of patients with TERT-wild-type and TERT-mutant tumors were analyzed. Early treatment responses at 1 and 2 years post-treatment and EFS were evaluated. Early treatment responses did not differ significantly between groups at 1 year (P = 0.212) and 2 years (P = 0.571). However, patients with TERT-mutant tumors had fewer excellent responses and higher rates of structural incomplete response. During follow-up, the TERT-mutant group experienced more recurrences and one disease-specific death. Cumulative EFS was significantly poorer in the TERT-mutant group than in the TERT-wild-type group (P = 0.022). Despite their low prevalence, TPMs were independently associated with adverse oncological outcomes, including higher rates of recurrence and mortality. TPMs may serve as valuable prognostic markers for early risk stratification in PTC.

Humans↗

PubMed2026

Machine Learning-Based Preoperative Predicting TERT Promoter Mutation and EGFR Gene Amplification Phenotype in IDH Wild-Type Glioblastoma Using Advanced MR Habitat Imaging.

BACKGROUND AND PURPOSE: The telomerase reverse transcriptase (TERT) gene promoter mutation is a crucial factor for identifying an isocitrate dehydrogenase (IDH) wild-type glioblastoma with poor prognosis, and the epidermal growth factor receptor (EGFR) amplification may be a potential prognostic factor. The purpose of this study was to investigate the value of the tumor habitats imaging model on advanced MRI in predicting TERT promoter mutation and EGFR gene amplification phenotype of IDH wild-type glioblastoma. MATERIALS AND METHODS: One hundred seventy-nine patients with pretreatment conventional MRI, DWI, and DSC-PWI were included. The data were divided into the training set (n=112), test set (n=29), and time-independent validation set (n=38). Based on the ADC and CBV map, the solid tumor area was split into several habitat subregions using the k-means clustering algorithm (hypovascular hypercellular area, hypervascular area, and hypovascular hypocellular area). In the training set, TERT promoter mutation and EGFR gene amplification phenotype prediction models were constructed using the random forest method. The reliability of prediction models was validated in the test and the time-independent validation sets. Receiver operating characteristic (ROC) curve analysis, calibration curve, and decision curve analysis (DCA) were used. RESULTS: The area under the curve (AUC) of the training, test, and validation sets of the TERT promoter prediction model was 0.877, 0.783, and 0.796, respectively. The accuracy of the TERT promoter prediction model was 82.1%, 75.9%, and 76.3%, respectively. The AUCs of the 3 sets for the EGFR gene amplification status prediction model were 0.877, 0.784, and 0.878, respectively. The accuracy of the EGFR gene amplification status prediction model was 79.5%, 75.9%, and 89.5%, respectively. Moreover, the prediction probability of these models was in good agreement with the actual result. CONCLUSIONS: The tumor habitat imaging model based on advanced MRI was useful for accurately predicting TERT promoter mutation and EGFR amplification status in IDH wild-type glioblastoma.

Humans↗

PubMed2024

Effects of particulate air pollution on BPDE-DNA adducts, telomere length, and mitochondrial DNA copy number in human exhaled breath condensate and BEAS-2B cells.

Traffic-related particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) have been linked to respiratory diseases and cancer risk in humans. Genomic damage, including benzo[a]pyrene diolepoxide (BPDE)-DNA adducts as well as alterations in telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN) are associated with respiratory diseases. This study aimed to investigate the association between exposure to traffic-related particulate pollutants and genomic damage in exhaled breath condensate (EBC) in human subjects and a bronchial epithelial cell line (BEAS-2B). Among the 60 healthy recruited subjects, residents living in high-traffic-congested areas were exposed to higher concentrations of PM2.5 (1.66-fold, p < 0.01), UFPs (1.79-fold, p < 0.01), PM2.5-PAHs (1.50-fold, p < 0.01), and UFPs-PAHs (1.35-fold, p < 0.05), than those in low-traffic-congested areas. In line with increased exposure to particulate air pollution, the high-traffic-exposed group had significantly increased BPDE-DNA adducts (1.40-fold, p < 0.05), TL shortening (1.24-fold, p < 0.05), and lower mtDNA-CN (1.38-fold, p < 0.05) in EBC. The observations in the human study linking exposure to PM2.5, UFPs, PM2.5-PAHs, and UFPs-PAHs with the aforementioned biological effects were confirmed by an in vitro cell-based study, in which BEAS-2B cells were treated with diesel exhaust particulate matter (DEP) containing fine and ultrafine PM and PAHs. Increased BPDE-DNA adducts levels, shortened TL, and decreased mtDNA-CN were also found in treated BEAS-2B cells. The shortened TL and decreased mtDNA-CN were in part mediated by decreased transcript levels of hTERT, and SIRT1, which are involved in telomerase activity and mitochondrial biogenesis, respectively. These results suggest that exposure to traffic-related particulate pollutants can cause genomic instability in respiratory cells, which may increase the health risk of respiratory diseases and the development of cancer.

Humans↗

PubMed2025

Deciphering estrogen receptor alpha-driven transcription in human endometrial stromal cells via transcriptome, cistrome, and integration with chromatin landscape.

OBJECTIVE: To investigate estrogen receptor gene 1 (ESR1) and estrogen-driven transcription in human endometrial stromal cells. DESIGN: RNA sequencing (RNA-seq) and Cleavage Under Targets and Release Using Nuclease (Cut&Run) were performed on telomerase-immortalized human endometrial stromal cells with Clustered Regularly Interspaced Short Palindromic Repeats-mediated ESR1 activation. Hi-C-based chromatin architecture analysis (H3K27ac HiChIP) was conducted in primary endometrial stromal cells. SUBJECTS: Biopsies from two healthy, reproductive-aged volunteers with regular menstrual cycles and no history of gynecological malignancies. EXPOSURE: The ESR1-activated and control endometrial stromal cells were treated with estradiol (E2) or vehicle. Primary endometrial stromal cells were treated with vehicle or a decidualization cocktail. MAIN OUTCOME MEASURES: Differential gene expression analysis (RNA-seq) identified ligand-independent and -dependent ESR1 activity. Cut&Run profiled ESR1 genomic binding in ESR1-activated cells. H3K27ac HiChIP mapped hormone-induced changes in chromatin looping in primary cells. RESULTS: Among seven tested guide RNAs (gRNA), the ESR1-3 gRNA induced robust ESR1 activation and restored E2 responsiveness. Bulk RNA-seq revealed both ligand-dependent and -independent ESR1 transcriptional programs regulating inflammation, proliferation, and cancer-related pathways. Notably, 72% of differentially expressed genes overlapped with genes active in human endometrial tissue during the proliferative estrogen-dominant phase, supporting their physiological relevance. The Cut&Run-seq identified genome-wide ESR1 binding sites, with most binding sites located at distal regulatory elements. Integration of Cut&Run data with H3K27ac HiChIP chromatin loops linked distal ESR1 binding sites to gene promoters, including genes involved in decidualization (e.g., FOXO1) and endometrial cancer (e.g., ERRFI1, NRIP1, and EPAS1). Functional assays showed that ESR1 promotes cell viability and, in the presence of E2, enhances migration. CONCLUSION: The CRISPR-mediated ESR1 activation restores estrogen responsiveness in endometrial stromal cells. Combined transcriptomic, cistromic, and chromatin architecture analyses reveal ESR1's role in regulating decidualization and inflammation-related gene networks, with relevance to endometrial pathologies including endometrial cancer. This model serves as a powerful tool to study estrogen signaling in endometrial stromal cell biology and related pathologies.

Humans↗

PubMed2025

Progesterone receptor isoform modulation via enhancer activation regulates progesterone signaling in endometrial stromal cells.

OBJECTIVE: To investigate enhancer-mediated regulation of progesterone receptor (PGR) isoforms, PGR-A and PGR-B, in human endometrial stromal cells, and to determine how isoform modulation shapes the progesterone-responsive transcriptome and cistrome relevant to endometrial function. DESIGN: A clustered regularly interspaced short palindromic repeats-based functional genomic screen was used to identify distal enhancers in telomerase-immortalized human endometrial stromal cells. Subsequent clustered regularly interspaced short palindromic repeats targeting of identified enhancers and the PGR promoter was used to modulate PGR isoform balance and assess functional consequences. SUBJECTS: None. EXPOSURE: Engineered endometrial stromal cells were treated with medroxyprogesterone acetate or vehicle. MAIN OUTCOME MEASURES: PGR isoform expression was assessed by western blot, the progesterone-responsive transcriptome was characterized by bulk ribonucleic acid sequencing, and the PGR cistrome was characterized by Cut&Run. RESULTS: Two distal PGR enhancers were identified in endometrial stromal cells located approximately 60 and 220 kb upstream of the PGR transcription start site. Clustered regularly interspaced short palindromic repeats-based activation of these enhancers upregulated both PGR-A and PGR-B, whereas promoter activation primarily upregulated PGR-B. Bulk ribonucleic acid sequencing revealed that shifting the PGR isoform balance altered the progesterone-regulated transcriptome: PGR-A/B-equivalent cells exhibited proinflammatory gene signatures, whereas PGR-B-dominant cells demonstrated suppression of inflammatory signaling and altered cell cycle programs. The PGR Cut&Run profiling revealed distinct genomic binding patterns associated with each isoform profile. Integration of the PGR cistrome with chromatin interaction maps suggested that these isoforms directly regulate distinct gene subsets involved in inflammation and fibrosis. Mechanistically, estrogen receptor alpha (ESR1) indirectly activated PGR-A expression, potentially through recruitment of Forkhead box protein O1 (FOXO1) at the distal enhancer, suggesting a noncanonical, enhancer-mediated mechanism of PGR regulation. CONCLUSIONS: Distal enhancers regulate the PGR isoform balance and shape the progesterone-responsive transcriptome in human endometrial stromal cells. This enhancer-mediated mechanism expands current models of PGR regulation beyond promoter-level control and may offer potential therapeutic targets to restore normal progesterone responsiveness in conditions marked by PGR isoform imbalance.

Humans↗