Telomerase RNA Research Articles

Canonical and extra-telomeric functions of telomerase: Implications for healthy ageing conferred by endurance training.

Telomerase preserves genomic integrity by maintaining and protecting the telomeres. Seminal findings from 1985 revealed the canonical role of telomerase and motivated investigations into potential therapeutic strategies to combat one of the hallmarks of ageing-telomere attrition. Since then, the field of telomere biology has rapidly expanded, with telomerase serving essential roles in cancer and cell development through its canonical function. However, telomerase also exerts critical extra-telomeric functions through its protein (telomerase reverse transcriptase, TERT) and RNA components (telomerase RNA component, TERC). Telomerase re-activation or ectopic expression promotes survival and permits unlimited proliferation in tumours and healthy non-malignant cells. TERT gene therapies improve health and lifespan in ageing mice and mouse models of age-related diseases. The extra-telomeric functions of telomerase are critical to ageing. These include protection against oxidative stress, orchestration of chromatin modifications and transcription, and regulation of angiogenesis and metabolism (e.g. mitochondrial function and glucose control). Given these biological functions are key adaptations to endurance training and the recent meta-analytical findings that indicate exercise up-regulates TERT and telomerase, a comprehensive discussion on the implications of the canonical and extra-telomeric roles of telomerase is warranted. This review highlights the therapeutic benefits of telomerase-based treatments for idiopathic and chronic diseases that are linked to ageing. Discussion on the canonical and extra-telomeric roles of telomerase are presented, followed by a detailed summary of the evidence on how exercise influences telomerase. Finally, the potential cell signalling underpinning the exercise-induced modulation of telomerase are discussed with directions for future research.

Abstract 3785: Telomerase RNA component lncRNA regulates hsa-miR-320 family and promotes prostate cancer metastasis

Abstract Telomerase RNA component (TERC) is a long non-coding (lncRNA) associated with prostate cancer progression and has novel prognostic biomarker potential. Differential methylation patterns of lncRNAs affect their expression levels, leading to cancer. This study aimed to profile and elucidate differential lncRNA expression patterns in prostate cancer (PCa). A 384-well plate of PCa associated lncRNA gene array panel was used in castration resistant PC-3 PCa cells vs androgen-sensitive PCa LNCaP cells. Annotation and enrichment analysis of lncRNA differential gene expression was performed using a human lncRNA sets database, LncSEA. Furthermore, digital droplet PCR (ddPCR) was used to verify the PCR array results. Up or down-regulation of ±2 and p <0.05 were considered significant. Decreased hsa-miR-320 gene family expression has been reported in various tumors including PCa. However, the precise mechanisms of hsa-miR-320 gene family in PCa remain to be elucidated. Thirty six of 84 lncRNAs were shown to be upregulated, while 14% of the lncRNA genes were downregulated. Notably, TERC lncRNA was upregulated in high metastatic PC-3 cells. Hypermethylation patterns of this lncRNA in high metastatic PC-3 cells was also shown by enrichment analysis. Furthermore, TERC lncRNA was demonstrated to regulate the hsa-miR-320 family, suggesting a correlation between TERC hypermethylation and downregulation of hsa-miR-320 gene family expression in PCa, as revealed by bioinformatics analysis. TERC lncRNA promotes PCa cell proliferation, migration, invasion and metastasis by sponging hsa-miR-320 family. This TERC/hsa-miR-320 interaction holds potential to understanding PCa prognostic mechanisms by lncRNAs and may also be targeted for novel therapeutics. Citation Format: Mandisa Mbeje, Jeyalakshmi Kandhavelu, Clement Penny, Zodwa Dlamini, Rahaba Marima. Telomerase RNA component lncRNA regulates hsa-miR-320 family and promotes prostate cancer metastasis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3785.

POP1 promotes the progression of breast cancer through maintaining telomere integrity.

Breast cancer is one of the most common and disastrous neoplasm for women worldwide, especially triple negative breast cancer (TNBC). Emerging evidences have demonstrated that RNase subunits are closely related to the occurrence and development of malignant tumors. However, the functions and underlying molecular mechanisms of Processing of Precursor 1 (POP1), a core component of RNase subunits, in breast cancer development have not been fully defined. Our study identified the POP1was upregulated in breast cancer cell lines and tissues and patients with higher POP1 expression were associated with poor outcomes. Overexpression of POP1 promoted cell progression in breast cancer cells, whereas silencing of POP1 induced cell cycle arrest. Moreover, Xenograft model reproduced its growth regulatory roles in breast cancer in vivo. Mechanistically, POP1 interacted and activated the telomerase complex by stabilizing the telomerase RNA component (TERC), thus protecting telomeres from shortening during division. Collectively, our findings demonstrate POP1 may as a novel prognostic marker and a therapeutic target for the management of breast cancer.

Overexpression of the telomerase holoenzyme induces EMT and tumorigenesis of HPV-immortalized keratinocytes.

Cervical cancer is the most frequent malignancy of the female genital tract and is associated with persistent infection of the uterine cervix with high-risk human papillomaviruses (HPV). The two HPV oncoproteins, E6 and E7, cooperatively immortalize cervical cells and are essential but insufficient for inducing tumorigenicity. During the progression of HPV-associated cervical dysplasia to carcinoma, the cellular telomerase reverse transcriptase (TERT) gene is activated and the TERC gene amplified. We questioned whether these increases in telomerase components might mediate the acquisition of the tumorigenic phenotype. We therefore transduced the TERT and TERC genes into E6/E7 immortalized keratinocytes that were anchorage-dependent and nontumorigenic. The resultant cells showed a profound morphological change characteristic of epithelial-mesenchymal transitionas well as a corresponding increase in expression of vimentin, N-cadherin, Zinc finger E-Box binding homeobox 1, snail family transcriptional repressor 1and matrix Metallopeptidase 2 and decrease in keratin and E-cadherin. More important, the transduced cells were now anchorage-independent and formed tumors in immunodeficient mice. Our findings indicate that overexpression of the telomerase holoenzyme in HPV-immortalized cells is sufficient to induce the complete transformed phenotype.

Triple signal amplification strategy for ultrasensitive in situ imaging of intracellular telomerase RNA

Abnormal upregulation of telomerase RNA (TR) is a hallmark event at various stages of tumor progression, providing a universal marker for early diagnosis of cancer. Here, we have developed a triple signal amplification strategy for in situ visualization of TR in living cells, which sequentially incorporated the target-initiated strand displacement circuit, multidirectional rolling circle amplification (RCA), and Mg2+ DNAzyme-mediated amplification. All oligonucleotide probes and cofactors were transfected into cells in one go, and then escaped from lysosomes successfully. Owing to the specific base pairing, the amplification cascades could only be triggered by TR and performed as programmed, resulting in a satisfactory signal-to-background ratio. Especially, the netlike DNA structure generated by RCA encapsulated high concentrations of DNAzyme and substrates (FQS) in a local region, thereby improving the reaction efficiency and kinetics of the third amplification cycle. Under optimal conditions, the proposed method exhibited ultrasensitive detection of TR mimic with a detection limit at pM level. Most importantly, after transfection with the proposed sensing platform, tumor cells can be easily distinguished from normal cells based on TR abundance-related fluorescence signal, providing a new insight into initial cancer screening.

Telomerase RNA plays a major role in the completion of the life cycle in Ustilago maydis and shares conserved domains with other Ustilaginales.

The RNA subunit of telomerase is an essential component whose primary sequence and length are poorly conserved among eukaryotic organisms. The phytopathogen Ustilago maydis is a dimorphic fungus of the order Ustilaginales. We analyzed several species of Ustilaginales to computationally identify the TElomere RNA (TER) gene ter1. To confirm the identity of the TER gene, we disrupted the gene and characterized telomerase-negative mutants. Similar to catalytic TERT mutants, ter1Δ mutants exhibit phenotypes of growth delay, telomere shortening and low replicative potential. ter1-disrupted mutants were unable to infect maize seedlings in heterozygous crosses and showed defects such as cell cycle arrest and segregation failure. We concluded that ter1, which encodes the TER subunit of the telomerase of U. maydis, have similar and perhaps more extensive functions than trt1.

Proteomic analysis defines the interactome of telomerase in the protozoan parasite, Trypanosoma brucei.

Telomerase is a ribonucleoprotein enzyme responsible for maintaining the telomeric end of the chromosome. The telomerase enzyme requires two main components to function: the telomerase reverse transcriptase (TERT) and the telomerase RNA (TR), which provides the template for telomeric DNA synthesis. TR is a long non-coding RNA, which forms the basis of a large structural scaffold upon which many accessory proteins can bind and form the complete telomerase holoenzyme. These accessory protein interactions are required for telomerase activity and regulation inside cells. The interacting partners of TERT have been well studied in yeast, human, and Tetrahymena models, but not in parasitic protozoa, including clinically relevant human parasites. Here, using the protozoan parasite, Trypanosoma brucei (T. brucei) as a model, we have identified the interactome of T. brucei TERT (TbTERT) using a mass spectrometry-based approach. We identified previously known and unknown interacting factors of TbTERT, highlighting unique features of T. brucei telomerase biology. These unique interactions with TbTERT, suggest mechanistic differences in telomere maintenance between T. brucei and other eukaryotes.

Long non-coding RNA telomerase RNA elements improve glucocorticoid-induced osteoporosis by EZH2 to regulate DKK1.

Glucocorticoid-induced osteoporosis is the most common secondary cause of osteoporosis, which increases the risk of fracture. Long non-coding RNA telomerase RNA elements (TERC) has been proven to be closely related to osteoporosis. However, the role of TERC in glucocorticoid-induced osteoporosis and its underlying molecular mechanism remains unclear. The in vitro model of osteoporosis was established after bone marrow mesenchymal stem cells (BMSCs) were exposed to dexamethasone (DEX). The cell viability, alkaline phosphatase (ALP) activity and mineralized nodules of BMSCs were evaluated. The messenger RNA and protein levels were detected by quantitative real-time polymerase chain reaction and Western blot. The interaction between TERC, enhancer of zeste homolog 2 (EZH2) and dickkopf-1 (DKK1) was confirmed by chromatin immunoprecipitation and RNA immunoprecipitation assays. Bone marrow mesenchymal stem cells were isolated, identified and induced osteogenic differentiation. The findings showed that the levels of osteogenic marker genes, including ALP, Runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN) in BMSCs were increased dependent on the osteogenic induction time. Similarly, TERC was significantly increased, but DKK1 was significantly decreased during BMSC osteogenic differentiation. Functional research showed that TERC overexpression promoted cell viability, ALP activity and mineralized nodules of BMSCs and increased the levels of osteogenic differentiation-related genes (ALP, RUNX2 and OCN), and TERC overexpression increased EZH2 protein level. Moreover, the decrease of cell viability, ALP activity and mineralized nodules induced by DEX was reversed by TERC overexpression. Furthermore, TERC inhibited DKK1 expression by promoting the histone modification of DKK1, and TERC overexpression alleviated DEX suppressed osteogenic differentiation of BMSCs by interaction with EZH2 to regulate DKK1. Our findings illustrated that TERC overexpression alleviated DEX-induced osteoporosis by recruiting EZH2 to regulate DKK1. Our research provided a novel direction for the treatment of glucocorticoid-induced osteoporosis.

Inhibition of TERC inhibits neural apoptosis and inflammation in spinal cord injury through Akt activation and p-38 inhibition via the miR-34a-5p/XBP-1 axis.

This study investigated the function of telomerase RNA component (TERC) in spinal cord injury (SCI). SCI models were established in rats via laminectomy and PC-12 cells were treated with lipopolysaccharide (LPS). TERC and miR-34a-5p expressions in cells and rat spinal cords were detected by quantitative reverse transcription polymerase chain reaction, followed by overexpression/knockdown of TERC/miR-34a-5p. Spinal cord histopathological changes were examined via hematoxylin-eosin staining. miR-34a-5p' relation with TERC and XBP-1 was predicted by TargetScan and checked by dual-luciferase reporter/RNA immunoprecipitation assays. Cell biological behaviors were assessed by Cell counting kit-8, wound healing, Transwell, and flow cytometry assays. XBP-1 and inflammation/apoptosis-related protein expressions were analyzed by western blot. TERC was upregulated and miR-34a-5p was low-expressed in SCI tissues and LPS-induced PC-12 cells. TERC-knockdown alleviated histopathological abnormalities yet upregulated miR-34a-5p in SCI tissues. In LPS-induced PC-12 cells, TERC knockdown promoted cell viability, migration, invasion, and inhibited apoptosis, while TERC overexpression ran oppositely. TERC knockdown downregulated the XBP-1, IL-6, TNF-α, Bax, p-p38/t-p38, and cleaved caspase-9/-3, but upregulated Bcl-2 and p-Akt/t-Akt. TERC targeted miR-34a-5p, which further targeted XBP-1. miR-34a-5p downregulation exerted effects opposite to and offset TERC knockdown-induced effects. TERC knockdown facilitated the regeneration of neuron tissues yet inhibited inflammation in SCI through Akt activation and p-38 inhibition via the miR-34a-5p/XBP-1 axis.

Features of molecular genetic diagnosis of verrucous leukoplakia

To evaluate the initial molecular genetic signs of malignancy of verrucous leukoplakia (VL). The study of VL was carried out on biopsies of 21 patients with the diagnoses of verrucous hyperplasia (VH) (15 cases - 71.4%) and verrucous carcinoma (VC) (6 cases - 28.5%). Tissue antigens were determined using mouse monoclonal antibodies to the Ki-67 protein (MM1, Diagnostic Biosystems). Telomerase activity was determined using rabbit immunoglobulin (TRT, Abbiotec). The amplification of the TERC (Telomerase RNA Component) portion of the RNA of the third chromosome was studied by the FISH method. In the studied groups, high cell proliferation and significant differences between HC and VC were revealed. The amplification of TERC by the FISH method made it possible to carry out differential diagnostics between VG and VC. According to the results of the study, the amplification of the TERC gene was detected in 100% in VC and in 20% in VG. The FISH method makes it possible to detect VL malignancy at an early stage. Amplification of the TERC gene is characteristic of malignant transformation of epithelial cells in VC. In IG, as a rule, there was no amplification, which can serve as evidence of the benign nature of the pathology of COP.

Молекулярно-генетические критерии малигнизации эпителия слизистой оболочки рта

Introduction. When examining the oral mucosa (OM) in the presence of an inflammatory process, the initial signs of malignancy are not always visible. Amid an inflammatory infiltrate, benign changes such as epithelial hyperplasia (EH), epithelial dysplasia (ED) of varying severity, and squamous cell carcinoma (SCC) can be hidden. The aim of the paper was to study the proliferative activity of epithelial cells of the OM, TERT expression, and amplification of telomerase TERC gene in the development of epithelial hyperplasia, dysplasia, and SCC. Materials and methods. We divided 60 patients into four groups: Group 1 with EH (n=16, 26.6%); Group 2 with low-grade epithelial dysplasia (LGED) [n=16, 26.6%]; Group 3 with high-grade epithelial dysplasia (HGED) [n=13, 21.6%]; and Group 4 with SCC (n=15, 25%). IHC and histological studies were carried out using standard methods; expression to Ki-67 protein and telomerase activity were evaluated. The FISH method was used with LSP TERC and CCP3 DNA probes. Results. High-cell proliferation and telomerase activity were revealed by IHC study in all groups. Amplification of TERC RNA site in chromosome 3 by FISH in Group 1 was almost absent and showed a 2:2 signal ratio in 1.3% of cases; in other groups, the amplification of TERC gene was positive: in groups 2, 3, and 4 it was in 83.9%, 97.3%, and 89.8% of cases, respectively. Conclusion. Amplification of TERC site signals in chromosome 3 is detected during malignization which may be the main criterion for early diagnosis of malignization of OM epithelium. Keywords: squamous cell carcinoma, epithelial dysplasia, TERC amplification, telomerase

Activity of the telomerase complex before and after CPAP therapy in patients with obstructive sleep apnea syndrome

To evaluate changes in the activity of the telomerase complex in patients with obstructive sleep apnea (OSA) before and after continuous positive airway pressure (CPAP) therapy. In accordance with the objectives of the stages of the study of telomers-telomerase relationships, we maintained the unified design of the study described earlier. The main group 1 (MG1), n=35, consisted of men, aged 53.4 [45.5-60.1] years with characteristic complaints indicating of OSA. The main group 2 (MG2) included the same patients before and after 6 months of CPAP therapy. Blood sampling was performed after the first diagnostic polysomnography (PSG) and after 6 months of CPAP in the morning after the second PSG. The control group (CG) consisted of 26 men, comparable in age and the presence of chronic diseases. Questionnaire, PSG and blood sampling were conducted in CG as well. All participants signed an informed consent. As a result of the STOP-BANG questionnaire conducted before PSG, all patients in the MG1 had scores from 5 to 8. The scores on the Epworth scale were more than 5 points. In the MG2 apnea-hypopnea index decreased from 20.1 to 6.4 ev/hour, the desaturation index decreased from 15.6 to 7.1 ev/hour after 6 months of CPAP. Statistically significant differences in changes in the activity of the telomerase complex were revealed, which after treatment significantly exceed the values of these indicators before treatment. So, telomerase reverse transcriptase value was 0.04 (0.009; 0.06) in the MG1, after treatment it was 0.07 (0.06; 0.09) in the MG2 and 0.134 (0.009; 0.18) in the CG. Telomerase RNA subunit TER1 values were 0.06 (0.03; 0.09), 0.07 (0.05; 0.09) and 0.136 (0.04; 0.17), respectively. However, despite the activation of the telomerase complex during CPAP therapy in patients with OSA, in the CG its activity is significantly higher in comparison with the MG1 and MG2. In OSA accompanied by intermittent hypoxia, a decrease in the activity of the telomerase complex was shown. Elimination of nocturnal hypoxia and improvement of breathing during sleep is accompanied by an increase in the activity of the components of the telomerase complex.

Molecular and genetic studies of polymorphic adenocarcinoma of the salivary gland: literature review and description of a clinical case

The article summarizes the literature data on the results of clinical, histological and molecular genetic studies of polymorphic adenocarcinoma. It is shown that the diagnosis of polymorphic adenocarcinoma presents difficulties due to the variety of morphological structure of its various components, which may correspond to the characteristics of other tumors of the salivary glands, such as pleomorphic adenoma and adenoid cystic carcinoma. Immunohistochemical markers characteristic of this pathology of the salivary glands are described. The article presents a rare clinical case of a male patient with polymorphic adenocarcinoma. Histological examination revealed perineural invasion and a characteristic immunohistochemical profile of tumor cells: low cell proliferative activity for the Ki-67 protein, a positive reaction to antigens: S100, SOX10, P63 and reverse transcriptase TERT. A study conducted by the FISH method revealed the amplification of the TERC gene, which indicates the malignant nature of this neoplasm. Conducting molecular genetic studies is of paramount importance for the diagnosis of polymorphic adenocarcinoma.

A Brief Overview of Telomeres and Telomerase in Aging and Cancer

Telomere is guanine-rich DNA sequence with a protein complex known as shelterin present at the chromosomal ends to protect it from destruction and is known to play a key role in aging. Telomerase is a telomeric DNA elongating enzyme, which comprises the central key components for telomeric DNA synthesis. The main objective of this review was to explore the structure and function of telomere and telomerase, and their intervention in aging, stem cells, and cancer cells. The induction of various telomeropathies and age-related diseases by Telomerase RNA component (TERC) impairment is well explained. Telomeropathies refer to bone marrow failures such as dyskeratosis congenita, aplastic anemia, etc. Telomere and telomerase have become the targets for age-related therapies, stem cell therapies, and cancer therapies. This article throws light on the telomerase-related therapies with natural compounds in regenerative medicine and cancer treatment. Telomerase inhibitors like nucleoside ligands and G4 ligands are explained in the context of anti-cancer drugs. The association of TERT promoter mutations with cancer is discussed. We conclude that understanding telomerase mechanisms in stem cells and cancer cells paves a way to translate stem cells, cancer cells, and age-related research into effective therapies. The dynamic features of telomerase and telomeres make their structural and biochemical studies difficult. Hence, further meticulous studies can be done on single-molecule approaches to facilitate feasible and effective studies of telomerase and telomere component functioning.

Telomerase RNA in Hymenoptera (Insecta) switched to plant/ciliate-like biogenesis.

In contrast to the catalytic subunit of telomerase, its RNA subunit (TR) is highly divergent in size, sequence and biogenesis pathways across eukaryotes. Current views on TR evolution assume a common origin of TRs transcribed with RNA polymerase II in Opisthokonta (the supergroup including Animalia and Fungi) and Trypanosomida on one hand, and TRs transcribed with RNA polymerase III under the control of type 3 promoter, found in TSAR and Archaeplastida supergroups (including e.g. ciliates and Viridiplantae taxa, respectively). Here, we focus on unknown TRs in one of the largest Animalia order - Hymenoptera (Arthropoda) with more than 300 available representative genomes. Using a combination of bioinformatic and experimental approaches, we identify their TRs. In contrast to the presumed type of TRs (H/ACA box snoRNAs transcribed with RNA Polymerase II) corresponding to their phylogenetic position, we find here short TRs of the snRNA type, likely transcribed with RNA polymerase III under the control of the type 3 promoter. The newly described insect TRs thus question the hitherto assumed monophyletic origin of TRs across Animalia and point to an evolutionary switch in TR type and biogenesis that was associated with the divergence of Arthropods.

Many Functions of Telomerase Components: Certainties, Doubts, and Inconsistencies

A growing number of studies have evidenced non-telomeric functions of "telomerase". Almost all of them, however, investigated the non-canonical effects of the catalytic subunit TERT, and not the telomerase ribonucleoprotein holoenzyme. These functions mainly comprise signal transduction, gene regulation and the increase of anti-oxidative systems. Although less studied, TERC (the RNA component of telomerase) has also been shown to be involved in gene regulation, as well as other functions. All this has led to the publication of many reviews on the subject, which, however, are often disseminating personal interpretations of experimental studies of other researchers as original proofs. Indeed, while some functions such as gene regulation seem ascertained, especially because mechanistic findings have been provided, other ones remain dubious and/or are contradicted by other direct or indirect evidence (e.g., telomerase activity at double-strand break site, RNA polymerase activity of TERT, translation of TERC, mitochondrion-processed TERC). In a critical study of the primary evidence so far obtained, we show those functions for which there is consensus, those showing contradictory results and those needing confirmation. The resulting picture, together with some usually neglected aspects, seems to indicate a link between TERT and TERC functions and cellular stemness and gives possible directions for future research.

Short Telomere Syndromes and Inherited Predisposition to Bone Marrow Diseases: The MDACC Experience

Introduction: Telomeres are noncoding nucleotide repeats at chromosomal ends, which provide genomic stability and are maintained and regulated by specific protein complexes. Their length physiologically decreases with age, although it is known that germline mutations in telomeric regulators can accelerate this process, which is related to a wide variety of clinical situations. Herein we report on the experience of patients diagnosed with Short Telomere Syndromes (STS) evaluated in the Hereditary Hematologic Malignancy Clinic (HHMC) of the MD Anderson Cancer Center. Methods: We retrospectively analyzed clinical characteristics and outcomes of patients with a diagnosis of STS referred or diagnosed in the HHMC. Germline mutation origin was confirmed by genetic analysis of cultured skin fibroblasts or blood/saliva in patients without hematologic disease. Telomere length was assessed by Flow-FISH techniques in a clinically validated external laboratory (John Hopkins Medical Laboratories, Baltimore, MD). Individuals with confirmed STS were recommended to follow a specialized cancer surveillance program to achieve early-diagnosis or prevention of potential complications related to STS. A baseline bone marrow evaluation was recommended to evaluate underlying morphology and assess for somatic comutations. Results: A total of 24 patients with STS were identified (13 males, 54%), with a median age of presentation to the clinic of 53 years old (5-78). Although the reasons of referral for STS testing for each individual patient were diverse, they can be summarized in these categories: unexplained cytopenia (n=9), myeloid malignancy with relevant PMH or FH (n=8), affected sibling (n=5), skin lesions (n=1) and multiple cancer diagnosis (n=1). Pathogenic or likely pathogenic germline variants were confirmed in the TERT gene (n=13, 54%), TERC gene (n=7, 29%), RTEL1 (n=2, 8%), while 2 patients had no telomere-related detectable mutations (Figure 1). Telomere flow-FISH confirmed age-predicted telomere length <1st percentile for age in 67(%). All patients underwent a bone marrow biopsy, being described as hypocellullar in 17 patients (71%). With the bone marrow evaluation, eleven patients were diagnosed with myelodysplastic syndrome (MDS, 46%), two patients with acute leukemia (myeloid and mixed phenotype, 8%), two patients with clonal cytopenia of unknown significance (CCUS, 8%), one aplastic anemia (4%) and eight patients (33%) did not have hematologic malignancy. During the follow-up, three patients underwent an allogeneic stem cell transplantation due to their hematologic disease. Solid neoplasms are frequent in patients with STS, and 11 patients (46%) had a PMH of at least one solid tumor with a median age of 54 (33-78 yrs). Squamous cell carcinoma was the most frequent histology (6/11 patients). Sixteen patients (67%) had a positive FH of cancer in one or more first or second-degree sibling. Pulmonary fibrosis (PF) was diagnosed in 4 patients (17%), two with TERT mutations and two with TERC mutations. Moreover, 7 patients (4 diagnosed with PF,30%) had a positive FH of PF in first degree siblings. Liver diseases were also frequent: 3 patients had non-alcoholic hepatic cirrhosis, one patient had chronic hepatitis with periportal fibrosis and one with idiopathic portal hypertension. One patient had received a liver transplantation and one required a lung transplantation prior to presentation to the HHMC. Finally, twelve patients (50%) were reported to have premature grey hair and eight patients were reported to have nail dysplasia and/or skin abnormalities related to STS (such as unexplained reticular rash). A summary of the described patients is depicted in Figure 2. Conclusion: STS are genetic diseases that can go unnoticed until adulthood. Patients with myeloid malignancies (especially MDS) with hypocellular bone marrow and suspicious findings (i.e. FH or PMH of PF, premature grey hair, long standing cytopenias) should be considered for underlying STS. An early diagnosis is essential to start cancer surveillance programs and provide timely genetic counseling to the patient and relatives. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Interstitial lung disease in a patient with premature aging: Suspected Werner syndrome

Werner syndrome (WS) is a rare inherited autosomal recessive disease that can be diagnosed with cardinal signs without the genetic testing. Some features that are consistent with WS include premature aging, loss, and graying hair, scleroderma-like skin changes. We report a 42-year-old man with cardinal signs of WS who also developed interstitial lung disease (ILD). The patient had past medical history (PMHx) of atypical left femur fracture in his early 30s from unknown causes. Also, he had loss and graying hair, salt-on-pepper skin changes, associated with squeaky voice, muscle wasting, and osteoporosis. He had worsening symptoms of dyspnea on exertion and was found with bilateral diffuse subpleural reticular opacities with slight mid- to lower-lung predominance and mild bronchiectasis without honeycombing or ground-glass airspace opacities on chest computed tomography (CT) scan. Other causes of ILD were excluded as patient routine laboratories and rheumatologic workup was negative. Werner syndrome presents similar features with other telomerase-associated diseases such as mutations of telomerase complexes [telomerase RNA component (TERC) and telomerase reverse transcriptase (TERT)]. Werner syndrome can be difficult to diagnose because it is a rare genetic disease that begins to show symptoms and signs after 10 or 20-year-olds, but the diagnosis is recognized after 30s. Few cases have been reported about the association of WS and ILD, but both diseases are aging diseases. This case might be the first case reported in Puerto Rico of Werner syndrome associated with ILD. Early referral and treatment is important to improve patients’ quality of life and life expectancy by slowing the progression of the disease.

A missense variant in the nuclear localization signal of DKC1 causes Hoyeraal-Hreidarsson syndrome

Hoyeraal-Hreidarsson syndrome (HHS) is the most severe form of dyskeratosis congenita (DC) and is caused by mutations in genes involved in telomere maintenance. Here, we identified male siblings from a family with HHS carrying a hemizygous mutation (c.1345C > G, p.R449G), located in the C-terminal nuclear localization signal (NLS) of the DKC1 gene. These patients exhibit progressive cerebellar hypoplasia, recurrent infections, pancytopenia due to bone marrow failure, and short leukocyte telomere lengths. Single-cell RNA sequencing analysis suggested defects in the NLRP3 inflammasome in monocytes and the activation and maturation of NK cells and B cells. In experiments using induced pluripotent stem cells (iPSCs) from patients, DKC1_R449G iPSCs had short telomere lengths due to reduced levels of human telomerase RNA (hTR) and increased cytosolic proportions of DKC1. Treatment with dihydroquinolizinone RG7834 and 3′deoxyanosine cordycepin rescued telomere length in patient-derived iPSCs. Together, our findings not only provide new insights into immunodeficiency in DC patients but also provide treatment options for telomerase insufficiency disorders.

Posttransplant Complications and Genetic Loci Involved in Telomere Maintenance in Heart Transplant Patients.

Reaching critically short telomeres induces cellular senescence and ultimately cell death. Cellular senescence contributes to the loss of tissue function. We aimed to determine the association between variants within genes involved in telomere length maintenance, posttransplant events, and aortic telomere length in heart transplant patients. DNA was isolated from paired aortic samples of 383 heart recipients (age 50.7 ± 11.9 years) and corresponding donors (age 38.7 ± 12.0 years). Variants within the TERC (rs12696304), TERF2IP (rs3784929 and rs8053257), and OBCF1 (rs4387287) genes were genotyped, and telomere length was measured using qPCR. We identified similar frequencies of genotypes in heart donors and recipients. Antibody-mediated rejection (AMR) was more common (p < 0.05) in carriers of at least one G allele within the TERF2IP locus (rs3784929). Chronic graft dysfunction (CGD) was associated with the TERC (rs12696304) GG donor genotype (p = 0.05). The genetic risk score did not determine posttransplant complication risk prediction. No associations between the analyzed polymorphisms and telomere length were detected in either donor or recipient DNA. In conclusion, possible associations between donor TERF2IP (rs3784929) and AMR and between TERC (rs12696304) and CGD were found. SNPs within the examined genes were not associated with telomere length in transplanted patients.